Fire is the main terrestrial ecosystem disturbance globally and a critical Earth system process. Fire research is rapidly expanding across disciplines, highlighting the need to advance our understanding of how fire interacts with land, atmosphere and society. This need is growing as fire activity increases in many world regions. This session invites contributions that investigate the role of fire within the Earth system across any spatiotemporal scale, using statistical (including AI) and process-based models, field and laboratory observations, proxy records, remote sensing, and data-model fusion techniques. We strongly encourage abstracts on fire's interactions with: (1) weather, climate, atmospheric chemistry, and circulation, (2) land physical properties, (3) vegetation composition and structure and biogeochemical cycle, (4) cryosphere elements and processes (such as permafrost, sea ice), and (5) human health, land management, conservation, and livelihoods. Moreover, we welcome submissions that address: (6) spatiotemporal changes in fire in the past, present, and future, 7) fire products and models, and their validation, error/bias assessment and correction, as well as (8) analytical tools designed to enhance situational awareness for fire practitioners and to improve fire early warning systems.

The Paris Agreement on Climate sets the international objective of reducing greenhouse gas (GHG) emissions to keep climate warming well below two degrees. However, quantifying past and present GHG emissions and sinks and predicting their future remains a substantial challenge. This challenge is primarily due to the high level of uncertainties in observing and modeling these GHG fluxes at regional to global scales. Thus, achieving climate and emission reduction targets requires a substantial improvement in our scientific ability to estimate the budgets and trends of these key major greenhouse gases (CO2, CH4 and N2O).

This session aims to bring together studies that seek to quantify past, present, and future global and regional budgets, trends and variability of major GHGs, as well as studies that contribute to understanding the key drivers and processes controlling their variations. We welcome contributions using a variety of approaches, such as emissions inventories, field and remotely sensed observations, terrestrial and ocean biogeochemical modeling, earth system modeling, and atmospheric inverse modeling. We encourage contributions integrating different datasets and approaches at multiple spatial (regional to global) and temporal scales (from past over the present and to the future) that provide new insights on processes influencing GHG budgets and trends in the past and future.

Anthropogenic disturbance of the global nitrogen (N) cycle has more than doubled the amount of reactive N circulating in the terrestrial biosphere alone. Exchange of reactive/non-reactive nitrogen gases between land and atmosphere including reactive N deposition on ecosystems are strongly affecting Earth’s atmospheric composition, air quality, global warming, climate change, human health and biodiversity. This session seeks to improve our understanding of a) how intensification of reactive N use, land management and climate change affects the pools and fluxes of nitrogen in terrestrial and aquatic ecosystems, b) and how reactive N enrichment of land and water will affect the future carbon sink of natural ecosystems as well as atmospheric exchanges of reactive (NO, N2O, NH3, HONO, NO2 and non-reactive N (N2) gases with implications for global warming, climate change and air quality, and c) how fluxes, in particular N deposition, can be quantified with the necessary accuracy to be used in nature protection policies as well as emission regulation and mitigation strategies. We welcome contributions covering a wide range of experimental and modelling studies, which covers microbes-mediated and physico-chemical transformations and transport of nitrogen across the land-water-air continuum in natural ecosystems from local to regional and global scales. Furthermore, the interactions of nitrogen with other elemental cycles (e.g. phosphorus, carbon) and the impacts of these interactive feedbacks for soil health, biodiversity and water and air quality will be explored in this session. Latest developments in methodological innovations and observational and experimental approaches for unravelling the complexities of nitrogen transformations and transport will also be of interest. This session will be celebrating its 10th anniversary for nitrogen science and cycling at the EGU2025.

In recent decades, extreme fire events have become increasingly common, exemplified by the recent fire seasons in Greece, Canada, Hawaii, California, Australia, Amazonia, the Arctic and the Pantanal. While these extremes and megafires have an exponential impact on society and all aspects of the Earth system, there is much to learn about their characteristics, drivers, links to climate change, and how to quantify their impacts, as well as mitigation and prevention strategies and tools.

One area of attention is how extreme fires are currently represented by different fire models. Due to their stochastic nature, uncertainty in observations, and the challenge of representing local processes within global models, extreme fires and their impacts still present a challenge to coupled modelling. The big data science models and machine learning approaches show promise in representing extremes but are weak in coupling feedbacks to vegetation, soils and the wider Earth System.

We also welcome case studies of regional extreme wildfire events, their impacts, and prevention and mitigation strategy experiences worldwide. We encourage contributions from a wide range of disciplines, including global, regional, and landscape modelling, statistical and process-based modelling, observations and field studies, science and social science studies on all temporal scales. In this session, we aim to share knowledge across multiple disciplines, from science to decision-makers and practitioners, to help overcome the challenges that wildfires pose to our models and our society.

We aim to explore the significance and interactions of extreme wildfires and their impacts on society and the earth system and identify the current gaps in our understanding to help us prepare for and mitigate future extreme wildfire events.

Dissolved and particulate organic carbon (DOM, POM) are key components of the global carbon cycle and are important as potential sources of CO2 and CH4, and for the long-term preservation of carbon stabilized in subsoils and sediments. DOM and POM are important sources of energy for microbial metabolism within terrestrial ecosystems, the aquatic continuum, and, ultimately, the ocean. Despite recent evidence showing this lateral transport of carbon is linked to anthropogenic perturbations, efforts to integrate DOM and POM fluxes across the terrestrial-aquatic continuum are just emerging. A comprehensive understanding of the dynamics of DOM and POM, and their interactions, in terrestrial and aquatic ecosystems remains challenging due to complex interactions of biogeochemical and hydrological processes at different scales, i.e. from the molecular to the landscape scale.
This session aims to improve our understanding of organic matter processing at the interface of terrestrial and aquatic ecosystems. We solicit contributions dealing with amounts, composition, reactivity, and fate of DOM and POM and the stoichiometry of its constituents (i.e., C, N, P, S) in soils, lakes, rivers, and the ocean as well as the impact of land use change and climatic change on these processes. For example, when assessing carbon dynamics across the terrestrial-aquatic continuum, it is important to recognize the key role of peatlands and peat restoration efforts as sources of organic matter for streams and rivers, as well as the contribution of mineral soil horizons to C fluxes at the catchment scale. Contributions addressing lateral fluxes of sediment and carbon induced by soil erosion or permafrost thaw are also welcome. We aim to bring together scientists from various backgrounds, but all devoted to the study of dissolved and/or particulate organic matter using a broad spectrum of methodological approaches (e.g. molecular, spectroscopic, isotopic, 14C, other tracers, and modeling).

Phosphorus (P) is an essential element for life on Earth and is tightly cycled within the biosphere. Throughout geological history, P availability has regulated biological productivity with impacts on the global carbon cycle. Today, human activities are significantly changing the natural cycling of P. Phosphate mining threatens P reserves, while increased inputs of P to terrestrial ecosystems have enhanced fluxes of P to lakes and the oceans.

Direct anthropogenic perturbations of the P cycle, coupled with other human-induced stresses, have impacted numerous environments. Forest ecosystems may be losing their ability to recycle P efficiently, due to excessive N input, extensive biomass removal, and climatic stress. Soils, which serve as the biogeochemical fulcrum of the terrestrial P cycle, have been greatly altered by fertilizer use in recent decades. Changes in the P cycle on land impact the magnitude and timing of P fluxes into aquatic ecosystems, influencing their trophic state. Burial in sediments returns P to the geological reservoir, eventually forming economically viable P deposits. Throughout the P cycle, redox conditions play a key role in transformations and mobility of P. Climate change and its mitigation affect and will further disrupt global P cycles. For example, the removal of CO2 from the atmosphere through an increase in global soil organic carbon stocks implies P sequestration.

This interdisciplinary session invites contributions to the study of P from all disciplines, and aims to foster collaborations links between researchers working on different aspects of the P cycle. We target a balanced session giving equal weight across the continuum of environments in the P cycle, from agriculture, forests, soils and groundwater, through lakes, rivers and estuaries, to oceans, marine sediments and geological P deposits. We welcome both empirical and modeling studies.

Mercury (Hg) pollution, stemming from both intentional use and unintentional emissions, poses a global threat to human health and wildlife. The urgency of this issue has led 149 countries to join the Minamata Convention on Mercury, which has been in effect since 2017 and is currently undergoing its first effectiveness evaluation. Research into Hg biogeochemical cycling has revealed its ubiquity and complex transformations across various environmental compartments, including the atmosphere, oceans, cryosphere, soils, vegetation, biota, and the anthroposphere. Understanding the future trajectory of Hg pollution and its environmental impacts requires an in-depth knowledge of the processes occurring within and between these compartments. This session invites studies that investigate Hg cycling within individual compartments, as well as studies that explore inter-compartmental interactions and their influence on the Hg cycle. Topics of interest include, but are not limited to, air-surface exchanges of Hg compounds, Hg (de)-methylation and bioaccumulation, sea ice processing, and climate/global change impacts on Hg cycling. We welcome presentations utilizing diverse methodologies, including laboratory experiments, field studies, mechanistic or statistical modelling, paleoenvironmental records, genomics, Hg stable isotopes, and emissions projections. Additionally, this session encourages contributions that aim to inform policy, including those associated with the Multi-Compartment Hg Modeling and Analysis Project (MCHgMAP).

Phenological changes induced by ongoing climate change are affecting species, ecosystems, and even the global climate by altering species performance, species interactions (potential mismatches and new opportunities in the food web), and water and carbon cycles. Observations of plant and animal phenology as well as remote sensing and modeling studies document complex interactions and raise many open questions about the future sustainability of species and ecosystems. In this session we invite all contributions that address seasonality changes based on plant and animal phenological observations, pollen monitoring, historical documentary sources, or seasonality measurements using climate data, remote sensing, flux measurements, modeling studies or experiments. We also welcome contributions addressing cross-disciplinary perspectives and international collaborations and program-building initiatives including citizen science networks and data analyses from these networks.
This session is organized by a consortium representing the International Society of Biometeorology (Phenology Commission), the Pan-European Phenology Network - PEP725, the Swiss Academy of Science SCNAT, the TEMPO French Phenology Network and the USA National Phenology Network.

The interactions between aerosols, climate, weather, and society are among the large uncertainties of current atmospheric research. Mineral dust is an important natural source of aerosol with significant implications on radiation, cloud microphysics, atmospheric chemistry, and the carbon cycle via the fertilization of marine and terrestrial ecosystems. Together with other light-absorbing particles, dust impacts snow and ice albedo and can accelerate glacier melt. In addition, properties of dust deposited in sediments and ice cores are important (paleo-)climate indicators.

This interdivisional session -- building bridges between the EGU divisions AS, CL, CR, SSP, BG and GM -- had its first edition in 2004 and it is open to contributions dealing with:

(1) measurements of all aspects of the dust cycle (emission, transport, deposition, size distribution, particle characteristics) with in situ and remote sensing techniques,
(2) numerical simulations of dust on global, regional, and local scales,
(3) meteorological conditions for dust storms, dust transport and deposition,
(4) interactions of dust with clouds and radiation,
(5) influence of dust on atmospheric chemistry,
(6) fertilization of ecosystems through dust deposition,
(7) interactions with the cryosphere, including also aerosols other than dust,
(8) any study using dust as a (paleo-)climate indicator, including sediment archives in loess, ice cores, lake sediments, ocean sediments and dunes,
(9) impacts of dust on climate and climate change, and associated feedbacks and uncertainties,
(10) implications of dust for health, transport, energy systems, agriculture, infrastructure, etc.

We especially encourage the submission of papers that integrate different disciplines and/or address the modelling of past, present, and future climates.

We are delighted to announce that in the 22nd edition of the dust session, Dr Patricia Castellanos (NASA) will provide a solicited talk about her work on airborne observations of dust.

Following the success of previous years, this session will explore reasons for the under-representation of different groups (gender identities, sexual orientations, racial and cultural backgrounds, abilities, religions, nationality or geography, socioeconomic status, ages, career stages, etc.) by welcoming debate among scientists, decision-makers and policy analysts in the geosciences.

The session will focus on both obstacles that contribute to under-representation and on best practices and innovative ideas to remove those obstacles. Contributions are solicited on the following topics:

- Role models to inspire and further motivate others (life experience and/or their contributions to promote equality)
- Imbalanced representation, preferably supported by data, for awards, medals, grants, high-level positions, invited talks and papers
- Perceived and real barriers to inclusion (personally, institutionally, culturally)
- Recommendations for new and innovative strategies to identify and overcome barriers
- Gender Equality Plans (GEP) in European host institutions: the good, the bad, and the ugly
- Best practices and strategies to move beyond barriers, including:
• successful mentoring programmes;
• networks that work;
• specific funding schemes;
• examples of host institutions initiatives;

Report on situations that you may have experienced in light of recent socio-political changes.

This session is co-organised with the support of the European Research Council (ERC).

Sitting under a tree, you feel the spark of an idea, and suddenly everything falls into place. The following days and tests confirm: you have made a magnificent discovery — so the classical story of scientific genius goes…

But science as a human activity is error-prone, and might be more adequately described as "trial and error", or as a process of successful "tinkering" (Knorr, 1979). Thus we want to turn the story around, and ask you to share 1) those ideas that seemed magnificent but turned out not to be, and 2) the errors, bugs, and mistakes in your work that made the scientific road bumpy. What ideas were torn down or did not work, and what concepts survived in the ashes or were robust despite errors? We explicitly solicit Blunders, Unexpected Glitches, and Surprises (BUGS) from modeling and field or lab experiments and from all disciplines of the Geosciences.

Handling mistakes and setbacks is a key skill of scientists. Yet, we publish only those parts of our research that did work. That is also because a study may have better chances to be accepted for publication in the scientific literature if it confirms an accepted theory or if it reaches a positive result (publication bias). Conversely, the cases that fail in their test of a new method or idea often end up in a drawer (which is why publication bias is also sometimes called the "file drawer effect"). This is potentially a waste of time and resources within our community as other scientists may set about testing the same idea or model setup without being aware of previous failed attempts.

In the spirit of open science, we want to bring the BUGS out of the drawers and into the spotlight. In a friendly atmosphere, we will learn from each others' mistakes, understand the impact of errors and abandoned paths onto our work, and generate new insights for our science or scientific practice.

Here are some ideas for contributions that we would love to see:
- Ideas that sounded good at first, but turned out to not work.
- Results that presented themselves as great in the first place but turned out to be caused by a bug or measurement error.
- Errors and slip-ups that resulted in insights.
- Failed experiments and negative results.
- Obstacles and dead ends you found and would like to warn others about.

--
Knorr, Karin D. “Tinkering toward Success: Prelude to a Theory of Scientific Practice.” Theory and Society 8, no. 3 (1979): 347–76.

Join us for an interdisciplinary session, where we will explore how cutting-edge omics technologies are transforming our understanding of ecosystems and their resilience in response to climatic change across all scales. Over billions of years, spatial and temporal shifts in environmental conditions have driven the evolution of diverse microbial, fungal, plant and animal species, shaping the ecosystems, atmosphere, and climate of Earth. Gaining insights into how these organisms and biomes function, adapt, and interact requires a deep understanding of their components and the complex feedback systems they form.

Technological innovations in measuring and interpreting “meta-omics” datasets are now providing unprecedented mechanistic insights across diverse organisms, scales, and environmental spheres. These advances also drive the development of next-generation models to predict ecosystem function. In this session, we bring together ecologists, geochemists, and evolutionary biologists to examine the available omics toolkits for studying organisms and communities and to discuss ongoing efforts to integrate this knowledge across biological and temporal scales to address pressing Earth system science questions.

By combining eco-evolutionary insights with ecosystem-level concepts like community traits and resilience, we aim to foster future ITS sessions that apply integrated omics approaches alongside geoscience techniques for a deeper, mechanistic understanding of ecosystems.

We welcome contributions studying all Earth’s spheres (Biosphere, Atmosphere, Hydrosphere, Cryosphere, Geosphere), using a wide range of omics datasets (metagenomics, metatranscriptomics, metabolomics, proteomics, lipidomics, spectranomics, ionomics, elementomics, and isotopomics) as well as other large datasets such as trait, phenotype, inventory, pollen, and fossil records. We are particularly interested in studies involving control experiments, long-term ecological surveys, or flux networks, as well as research that provides mechanistic insights and employs big data in Earth system models or machine learning to scale patterns across space and time.

Advances in forest system modelling and monitoring techniques are crucial for deepening our understanding of forest ecosystems and their dynamic responses to environmental stresses and disturbances. These advancements are instrumental in addressing global environmental challenges by improving predictions and adapting management strategies accordingly. This session aims to bring together scientists and researchers focused on the latest advancements in forest systems modelling, observational techniques, and analytical methodologies to enhance our understanding of forest structural dynamics, soil carbon (C) dynamics, and the impacts of natural disturbances such as wildfires, insect’s outbreaks, pathogens/disease, droughts, and windstorms. Specifically, this session covers the following topics:

• Advancements in Forest System Modelling: Presentations on new models or significant improvements in existing models, that help predict and analyse forest growth, structural dynamics, C sequestration in biomass and soils, and ecosystem resilience. This includes models that integrate hydrological, meteorological, and biological processes.

• Innovative Monitoring Techniques: Studies showcasing novel observational technologies or methodologies, including remote sensing, isotopic tracing, or ground-based monitoring systems that provide new insights into forest mortality, growth patterns, and C cycling.

• Impact of Natural Disturbances: Research on how wildfires, insect’s outbreaks, pathogens/disease, droughts, and severe wind events alter forest structure, soil C stocks, and overall ecosystem functions. Contributions may include forward-looking information, post-disturbance recovery processes, disturbance modelling, and strategies for disturbance mitigation and adaptation.

• Cross-Scale Integration: Contributions that demonstrate the integration of innovative integrations of data and models across different spatial and temporal scales to understand forest biomass and soil dynamics comprehensively.

• Implications for future Management Strategies: Insights into how advanced modelling and monitoring approaches can shape policy development, offer a range of adaptation strategies, and inform management practices to enhance forest resilience and C retention.

Disturbances, such as extreme weather events, play a key role in shaping ecosystems. Under climate change, extreme weather hazards undergo changes in frequency, intensity and seasonality. While ecosystem-based adaptation and nature-based solutions are gaining traction, it is crucial to elucidate the diverse interactions between extreme weather risk, ecosystems, and their services.

This session seeks to highlight research on the nexus of extreme weather events and ecosystems. This includes: 1) investigations into the key attributes and patterns of extreme weather events which affect ecosystem composition, structure and functioning. 2) studies on how ecosystems respond to and recover from extreme weather events across past, present, and future climates are of interest. 3) Implications of extreme weather impacts on ecosystems for biodiversity and ecosystem service provision. We welcome a diverse array of contributions, including theoretical analyses, modeling approaches, field studies, experimental designs, and remote sensing analysis.

Key topics include:
- Ecosystem (terrestrial, coastal or marine) responses to extreme weather
- Role of extreme weather in shaping ecosystem composition, biodiversity, structure and functioning
- Vulnerability assessments of ecosystems
- Natural hazard risk to ecosystems in past, present and future climates
- Changes in ecosystems service provisions due to extreme weather events
- Resilience and recovery dynamics
- Impact and efficacy of Nature-Based Solutions (NBS) under extreme conditions, risk of maladaptation or disservices
- Regime shift / tipping points in ecosystems due to extreme weather events
- Extreme weather disturbance regimes affecting ecosystems across time
- Identification of extreme weather risk hotspots
- Interactions of natural hazard and anthropogenic disturbances to ecosystems

The session aims to explore the intricate relationships between living organisms and the Earth system from different angles. It highlights research on the influence of biodiversity, and animals, on ecosystem functioning and resilience. While biological diversity is vital for natural ecosystems such as forests and wetlands, and crucial for maintaining healthy freshwater ecosystems, soil systems, and oceans, it is also a factor that affects an ecosystem’s response to disturbances, in turn affecting notions such as (ecosystem) integrity, health and resilience. Animals, on the other hand, are an integral part of the biosphere within the Earth system, and a growing body of evidence suggests that, despite their small biomass compared to plants and microbes, the animals in terrestrial and aquatic biomes are important geoengineers of both the physical and chemical environment.
Adopting an interdisciplinary approach, the session invites contributions from fields such as geosciences, ecology and modelling, recognizing the interplay between biological and physical processes in controlling key planetary processes such as water, carbon and nutrient cycling, as well as geomorphic processes. This comprehensive, broader approach helps highlight several distant topics, such as: how biodiversity affects ecosystem integrity, health, and response to disturbances; how it influences processes such as restoration, and rewilding, including reintroduction of large animals to restore ecosystem functioning. The session also focuses on the specific contributions of animals to Earth system processes, as the emerging discipline of zoogeoscience including biogeochemical cycles and physical displacement of soils and sediments and bioturbation. Finally, the session also addresses and it underscores the importance of scientific evidence in informing political decisions, such as the EU Nature Restoration Law.
In sum, in this session we aim to recognize the wide range of biogeoscience, and the broader Earth system science research projects with an aim to understand the functional role of biodiversity in the Earth system, and highlight the need for interdisciplinary research and the importance of studying these processes at various spatial and temporal scales. This session is combined from sessions ITS3.7/BG0.6 Biodiversity from a Geoscience perspective and BG1.9 Animals in the Earth System.

Global change drivers on ecosystems, such as land/sea use change, direct exploitation, climate change, pollution, and invasive alien species are the major contributors to the accelerating biodiversity crisis and shifts in biome boundaries. Mounting evidence has demonstrated the link between these drivers and changes in biodiversity, such as the loss of species, declines in functional and genetic diversity, and reduction in geodiversity. However, our understanding of the impacts of these drivers on biodiversity across local to global scales remains limited. In this session, we warmly invite contributions related but not limited to studies on 1) the current state or patterns of biodiversity and main drivers; 2) changes in biodiversity and ecosystem functioning; 3) trends and future scenarios of biodiversity change; 4) species migrations and links to environmental and anthropogenic influences, and 5) changes in biodiversity resulting from conservation, restoration, management and policy.

We aim to bring together excellent research about past, present, and future biodiversity, using data from field sampling, and airborne or space-based remote sensing observations. We welcome studies ranging from local-scale field experiments to large-scale theoretical modeling, including both individual-ecosystem (i.e. terrestrial, marine and freshwater systems) and cross-ecosystem studies. We explicitly welcome novel conceptual ideas, large-scale observations, field experiments, earth system modeling, or data synthesis related to biodiversity change across spatial and temporal scales, and from various data sources toward a better understanding of global change impacts on biodiversity.

BG3.20 Borealization of tundra ecosystems

Arctic and alpine tundra ecosystems are changing fast in response to ongoing climate change and increased human pressures linked to land use changes. One observed phenomenon in response to these changes is the northward and upward shift in the distribution of temperate or boreal species from southerly latitudes or lower elevations, a process known as borealization. Examples of tundra borealization include the encroachment of woody species, the spread of non-native species, and changes in the composition of plant, animal and microbial communities. Borealization also alters the trophic and functional structure of ecosystems, changes landscape structure and impacts ecosystem processes such as the strength of carbon sink and sources.

This session is open to all contributions in biogeochemistry and ecology where stable isotope techniques are used as analytical tools, with foci both on stable isotopes of light elements (C, H, O, N, S, …) and new systems (clumped and metal isotopes). We welcome studies from both terrestrial and aquatic (including marine) environments as well as methodological, experimental and theoretical studies that introduce new approaches or techniques (including natural abundance work, labelling studies, modeling).
Results from the successful EGU sessions on the ‘Application of Stable Isotopes in Biogeosciences’ that took place earlier have been published in several special issues of Organic Geochemistry and Isotopes in Environmental & Health Studies.

We welcome contributions involving the use of stable isotopes of light elements (C, H, O, N, S) or novel tracers (such as COS) in field and laboratory experiments, the latest instrument developments, as well as theoretical and modelling activities, which advance our understanding of biogeochemical and atmospheric processes. We are particularly interested in the latest findings and insights from research involving:

- Isotopologues of carbon dioxide (CO2), water (H2O), methane (CH4), carbon monoxide (CO), oxygen (O2), carbonyl sulfide (COS), and nitrous oxide (N2O)

- Novel tracers and biological analogues

- Polyisotopocules including "clumped isotopes"

- Non-mass-dependent isotopic fractionation and related isotope anomalies

- Intramolecular stable isotope distributions ("isotopomer abundances")

- Quantification of isotope effects

- Analytical, methodological, and modelling developments

- Flux measurements

Lipid biomarkers are valuable tools for reconstructing a variety of environmental processes in modern and (geological) past settings. Application of lipid biomarkers includes analyzing the distribution and stable isotopic composition of core lipids (e.g., n-alkanes, fatty acids, alkenones, sterols, hopanoids, HBIs, HGs, and GDGTs) and intact polar lipids in the environment. Given complex relationships between biogenic organic compounds and environmental conditions, it is crucial to understand the mechanisms that influence their molecular distribution and isotopic composition in diverse depositional environments. This includes identifying biogenic sources, physiological effects, evidence of transport, post-depositional processes, and diagenesis.
We seek studies that develop new lipid biomarkers and methods for applying biomarkers to modern settings and the geologic past in order to reconstruct environmental parameters such as temperature, precipitation, biogeochemical cycles, anthropogenic activities, and vegetation. These can be studies on the biosynthesis and phylogeny of source organisms, transport and diagenesis, calibrations to environmental parameters, proxy interpretation and applications to reconstruct past environmental conditions.

The interplay between natural organic matter (NOM) including organic contaminants and decomposer communities at the nexus of solids, solutes and volatiles regulates a C reservoir larger than all living biomass on Earth, making it a keystone in the global carbon cycle. Despite its ubiquitousness, NOM remains a black box due to its astonishing molecular complexity. Advances in ultrahigh resolution mass spectrometry (FT-ICR-MS, Orbitrap, TOF-MS) have enabled researchers to analyze NOM and contaminants in all forms - solid, soluble and volatile - on the molecular-level. Ultimately, this allows to resolve the molecular complexity of NOM, and to elucidate its mediating role in various processes essential for life on Earth, such as energy flow, nutrient retention and resupply, or climate stability.

The challenge ahead of us is to synthesize the gained knowledge from various research communities (biogeochemistry, soil sciences, atmospheric sciences, aquatic sciences, analytical chemistry, geomicrobiology), ultimately providing useful data and process understanding to integrate in C cycle models that represent its molecular complexity in a more realistic way. To achieve this, it is also required to develop computational methods to align FT-ICR-MS data with complementary spectroscopic and mass spectrometric techniques (NMR, FT-IR, XPS, py-GC-MS, EEMs-PARAFAC, PTR-MS, etc.) and allow for a community-driven effort to share, curate and compare global molecular-level datasets.

In this session we therefore welcome proceedings in the following domains:
- Experimental, e.g. focusing on single or combined processes of natural and anthropogenic organic matter biogeochemistry or its links with other drivers such as microbial communities,
- Field-scale, e.g. studying the behavior of NOM across environmental gradients or interfaces,
- Modeling and simulation, e.g. integrating molecular-level data to improve the prediction of environmental processes or simulate ecosystem functioning,
- Computational, e.g. bioinformatic approaches to facilitate the analysis of molecular-level NOM data, or allowing its integration with complementary data streams,
- Analytical, e.g. improving or expanding the measurement of NOM on the molecular level, or providing novel tools to reveal its properties, responses or effects

We are looking forward to bringing together researchers from a wide range of disciplines to share their perspectives on studying NOM at EGU25!

The increased attention of society to climate change, drought and flood early warning systems, ecosystem monitoring and biodiversity conservation has led to a large demand for estimating, modelling, mapping, and forecasting evapotranspiration (ET) as a key water flux at the soil-vegetation-atmosphere interface. Cutting-edge techniques such as artificial intelligence (AI), data fusion, sharpening algorithms, and the integration of physical- and process-based models with empirical/statistical methods and machine learning are essential for bridging different scales while addressing and communicating method-specific uncertainties.

This session will focus on various ET estimation methods, including sap flow or soil heat pulse sensors, lysimeters, eddy covariance stations, scintillometers, and remote sensing. We will also explore new techniques like AI, data fusion, sharpening algorithms, machine learning, and cloud computing. Additionally, we will cover detailed evaluations of scale dependencies, strategies to handle uncertainties, systematic biases, and the representativity of estimates.

We welcome contributions that (1) assess and compare various in-situ and remote sensing methods, (2) analyse trends and spatio-temporal patterns in ET data, including error sources and uncertainty, (3) bridge scales between different in-situ measurements, modelled and remotely sensed ET, including validation and calibration challenges, (4) evaluate challenges and opportunities of applying AI methods, cloud computing and new technologies.

Stable and radiogenic isotopic records have been successfully used for investigating various terrestrial and marine sequences, fossils, evaporative rocks, palaeosols, lacustrine, loess, caves, peatlands. In this session we are looking for contributions using isotopes along with sedimentological, biological, paleontological, mineralogical, chemical records in order to unravel past and present climate and environmental changes or as tracers for determining the source of phases involved. Novel directions using triple isotopes, clumped isotopes, biomarkers are welcomed.
The session invites contributions presenting an applied as well as a theoretical approach. We welcome papers related to reconstructions (at various time and space scales), fractionation factors, measurement methods, proxy calibration, and verification.

INTIMATE (INTegrating Ice core, Marine and TErrestrial records) is a large, diverse, international scientific network interested in better understanding abrupt and extreme climate changes in the Northern Hemisphere during the Quaternary. INTIMATE’s fundamental approach is the synchronisation and comparison of high resolution palaeoclimate and environmental records based on their independent timescales.

While the need for global cooperation in the face of global trends is obvious, funding mechanisms for environmental research and monitoring are still largely organised on a national and regional basis. Despite declared intentions to improve cooperation and thematic coordination in the formulation of related research and infrastructure programmes, concrete cooperation is hampered by a lack of resources and time for consultation, even in the case of thematically appropriate calls. This affects not only collaborative projects but also the improvement of interoperability and, ultimately, the concerted development and sustainable operation of services. Initiatives such as the G8 Group of Senior Officials (GSO) with its Recommendations for Global Research Infrastructures (GRI) have not led to a structural improvement of the situation. Still, Environmental Research Infrastructures (ENVRIs), have become a key instrument in environmental science and science-driven environmental politics.
Contributions to this session should present successful examples, experienced constraints and derived recommendations for action. They might address the value chain from open standardised observations and experiments data via scientific analysis towards societal impact through actionable knowledge, but also refer to,basic ENVRI activities like access to long-term operated in-situ facilities. An Impact Lecture will introduce the Global Ecosystem Research Infrastructures Initiative, in which SAEON/South Africa, TERN/Australia, CERN/China, NEON/USA, ICOS/Europe and eLTER/Europe will present their work on harmonised data systems, training and development, and collaboration in the use case 'ecological drought'.

Agrogeophysics harnesses geophysical methods such as ground-penetrating radar, electrical imaging, seismic,... from hand-held over drone to satellite-borne, to characterize patterns or processes in the soil-plant continuum of interest for agronomic management. These methods help develop sustainable agricultural practices by providing minimally-invasive, spatially consistent, multi-scale, and temporally-resolved information of processes in agro- ecosystems that is inaccessible by traditional monitoring techniques. The aim of this session is to feature applications of geophysical methods in agricultural research and/or show methodologies to overcome their inherent limitations and challenges. We welcome contributions monitoring soil or plant properties and states revealing information relevant for agricultural management; studies developing and using proximal or remote sensing techniques for mapping or monitoring soil-water-plant interactions; work focused on bridging the scale gap between these multiple techniques; or work investigating pedophysical relationships to better understand laboratory-scale links between sensed properties and soil variables of interest. Submissions profiting on data fusion, utilizing innovative modeling tools for interpretation, and demonstrating novel acquisition or processing techniques are encouraged.

The terrestrial vegetation carbon balance is controlled not just by photosynthesis, but by respiration, carbon allocation, turnover (comprising litterfall, background mortality and disturbances) and wider vegetation dynamics. Recently observed changes in vegetation structure and functioning are the result of these processes and their interactions with atmospheric carbon dioxide concentration, nutrient availability, climate, and human activities. The quantification and assessment of such changes has proven extremely challenging because of a lack of observations at spatio-temporal scales appropriate for evaluating trends and projecting them into the future.

This limited observation base gives rise to high uncertainty regarding the future terrestrial carbon sink. Many questions need answer to determine if it will be sustained under future environmental changes, or whether increases in autotrophic respiration or carbon turnover might counteract this negative feedback to climate change. For instance, will accelerated background tree mortality or more frequent and more severe disturbance events (e.g. drought, fire, insect outbreaks) turn vegetation into carbon sources? How will shifts in dynamics of plant mortality, establishment, and growth influence forest composition?

Uncertainties and/or data gaps in large-scale empirical products of vegetation dynamics, carbon fluxes and stocks may be overcome by extensive collections of field data and new satellite retrievals of forest biomass and other vegetation properties. Such novel datasets may be used to evaluate, develop and parametrize global vegetation models and hence to constrain present and future simulations of vegetation dynamics. Where no observations exist, exploratory modelling can investigate realistic responses and identify necessary measurements. We welcome contributions that make use of observational approaches, vegetation models, or model-data integration techniques to advance understanding of the effects of environmental change on vegetation dynamics, tree mortality as well as carbon stocks and fluxes at local, regional or global scales and/or over long periods.

Human activities on land (LULCC) shape climate by altering land-atmosphere fluxes of carbon, water, energy, and momentum. An increasing focus on land-based climate mitigation and adaptation strategies to meet more stringent targets has expanded the range of land management practices considered specifically for their potential to alter terrestrial carbon cycling or mediate favorable environmental conditions. This focus has also called attention to potential tradeoffs between climate-centric aspects of LULCC and its influences on biodiversity, hydrology and other environmental factors. Advancements in modeling and measurement techniques are opening new possibilities to better describe LULCC and its effects on the Earth system at multiple temporal and spatial scales.

This session welcomes all contributions aimed at furthering our understanding of LULCC in the Earth system, including those addressing LULCC effects on carbon, climate, hydrology, and/or biodiversity, and aims to present studies that can inform adoption of appropriate land-based strategies for climate mitigation, adaptation, and ecosystem restoration.

Plant traits extend the range of earth observations to the level of individual organisms, providing a link to ecosystem function and modelling in the context of rapid global changes. However, overcoming the differences in temporal and spatial scales between plant trait data and biogeochemical cycles remains challenging.

This session will address the role of plant traits, biodiversity, acclimation, and adaptation in the biogeochemical cycles of water, carbon, nitrogen, and phosphorus. We welcome conceptual, observational, experimental and modelling approaches and studies from the local to the global scale, including in-situ or remote sensing observations.

Although climate change is a natural process, it is significantly stimulated by anthropogenic activities. The acceleration of climate change is directly connected with ecological stability, soil degradation, and hydrological extremes, which are considered as the main consequences of climate change. As climate change intensifies, extreme and unexpected weather events are becoming more frequent.
The aim of this session is to highlight a broad range of research methods and results related to climate change. This interdisciplinary session should reflect, discuss, and share scientific knowledge on a local and regional scale with the aim to increase innovative knowledge on climate change and its impacts, ecosystem response and new techniques to prevent and reduce the negative consequences.

This session encourages contributions from several fields related to:
- climate change impacts (biodiversity loss, rising temperatures, hydrological extremes, soil degradation, ecosystem response to climate change);
- droughts and floods; precipitation deficiency or extreme precipitation with solutions aimed at reducing the negative impacts;
- ecological stability and climate change; changes of ecological stability, deforestation, human interactions with the environment and evaluation of restoration success;
- green cities to increase the ecological stability of the urban landscape;
- techniques and methods to prevent and reduce the negative impacts of climate change (such as soil degradation, carbon sequestration, changes in natural, agricultural, and forest ecosystems, reduction of overall ecological stability and character of the landscape);
In addition, attention will be given to the sustainability of management practices, the importance of appropriate land use management as the main tool for preventing the degradation processes, the distribution and vitality of ecosystems, and improving the condition of forest ecosystems in order to increase the overall character of the landscape.

Human activities are altering a range of environmental conditions, including atmospheric CO2 concentration, climate, and nutrient inputs. Understanding and predicting their combined impacts on biogeochemical cycles, ecosystem structure and functioning is a major challenge. Divergent future projections of terrestrial ecosystem models reveal uncertainties about fundamental processes and missing observational constraints. Models are routinely tested and calibrated against data from ecosystem flux measurements, remote sensing, atmospheric inversions and ecosystem inventories. However, it remains challenging to use available observations to constrain process representations and parameterizations in models simulating the response of ecophysiological, biogeochemical, and hydrological processes to environmental changes.

This session focuses on the influence of CO2, temperature, water stress, and nutrients on ecosystem functioning and structure. A focus is set on learning from manipulative experiments and novel uses of continuous ecosystem monitoring and Earth observation data for informing theory and ecosystem models. Contributions may cover a range of scales and scopes, including plant ecophysiology, soil organic matter dynamics, soil microbial activity, nutrient cycling, plant-soil interactions, or ecosystem dynamics.

The need to predict ecosystem responses to anthropogenic change, including but not limited to changes in climate and increased atmospheric CO2 concentrations, is more pressing than ever. Global change is inherently multi-factorial and as the terrestrial biosphere moves into states without a present climate analogue, mechanistic understanding of ecosystem processes and their linkages with vegetation diversity and ecosystem function is vital to enable predictive capacity in future forecast tools.

This session is about process understanding of scalable ecophysiology and ecosystem function relevant to carbon and water cycles, above- and below-ground. We facilitate dialogue across scales and techniques, from mesocosm experiments to field experiments, remote sensing and modelling.

A robust representation of terrestrial carbon, nitrogen, and water cycles requires a fundamental understanding of biosphere-atmosphere interactions, particularly in the context of a rapidly changing climate. However, a significant challenge arises from the mismatch that occurs when carbon, water, or nitrogen fluxes are measured or modelled at different spatio-temporal scales. Multiple processes determine how mass and energy exchanges scale from the leaf, to the whole plant, to the ecosystem, and eventually to the globe. Despite the evolution of Earth system models to incorporate increasingly complex processes across these scales, uncertainties persist due to these mismatches. The unprecedented rate of climate change, along with the increasing frequency and intensity of extreme events, further complicates our ability to robustly formulate mechanistic underpinnings of biogeochemical processes across scales.
The increasing volume of data at multiple scales—from leaf-level measurements (e.g., gas exchange), tree-level measurements (e.g., sap flow and dendroecology), ecosystem-level measurements (e.g., eddy covariance towers, UAVs, aircraft), to Earth observation from space—presents new opportunities to address these challenges. This session invites studies that improve our overall understanding of biosphere-atmosphere interactions by addressing the mismatches across different temporal and spatial scales and integrating these insights into modeling strategies. We particularly encourage contributions that explore the effects of climate extremes (e.g., drought, heatwaves, excess rainfall, winter warming) on carbon, nitrogen, and water fluxes. In addition to empirical multi-scale observations, we welcome research that delves into data-driven diagnostics and constraints for model evaluation, data-driven parameterisations in mechanistic models, and the development of data-driven/hybrid modelling strategies (i.e., seamless fusion of data-driven approaches and mechanistic models) for an integrated understanding of carbon, nitrogen, and water fluxes across scales.

This session aims to bring together scientists actively engaged in ecosystem modelling and monitoring to discuss recent advancements in understanding ecological and microclimatic processes within terrestrial ecosystems. As climate change continues to impact terrestrial ecosystems worldwide, improving the presentation of process interactions and climate response is crucial for accurately predicting future changes and gaining insights into terrestrial feedback on the atmosphere and climate.

We invite abstracts that address, but are not limited to, the following themes:
(1) Advances in representing responses of terrestrial ecosystem processes to climate variability and extremes;
(2) Advances in representing microclimatic conditions in terrestrial ecosystem models;
(3) Advances in accounting for species dynamics, biodiversity, changes in ecosystem composition and interactions;
(4) Methods for improving the understanding of ecological processes and interactions in different terrestrial ecosystems;
(5) site, regional and global studies taking advantage of in-situ measurements, Earth observing systems (EOS) or laboratory experiments to improve ecosystem model processes and microclimate conditions.

Extremes in temperature, vapor pressure deficit, and soil moisture severely endanger critical functions and services provided by terrestrial ecosystems. Both increasingly extreme long-term trends in environmental conditions and extreme events such as heatwaves, droughts, floods, and unseasonal freezes directly impact key physiological processes such as carbon uptake, transpiration, growth, and mortality. An abundance or scarcity of water, atmospheric dryness, heat, and cold can operate separately or in tandem to cause reductions in terrestrial gross and net primary productivity and elevated risks of plant mortality. However, due to the complexity of these interactions and the scarcity of continuous time series, it is difficult to quantify the magnitude and timing of temperature and water stress-related impacts on ecosystem function. As climate change accelerates the occurrence and severity of climatic extremes with consequences for terrestrial ecosystems, we must harmonize our efforts to characterize plant and ecosystem functions and develop frameworks for monitoring and prediction.

In this session, we broadly explore the roles of temperature extremes, evaporative demand, and soil moisture in carbon, water, and energy relations, along with plant mortality across various spatial and temporal scales. We encourage submissions dealing with novel approaches for measuring and modeling plant and soil water status, responses to extreme conditions, and their impacts on ecosystem function. We invite contributions on these topics at scales ranging from individual plant tissues to entire ecosystems, applying experimental, observational, or modeling approaches and dealing with diverse disciplines such as plant physiology, community ecology, ecosystem ecology, land management, and biogeochemistry.

Tropical ecosystems are biomes of global significance due to their large biodiversity, carbon storage capacity, and their role in the hydrological cycle. Historical and recent human activities have, however, resulted in an intensive transformation of the tropical ecosystems in the Amazon, Central America, Central Africa and South East Asia, impacting the cycling of nutrients, carbon, water, and energy. Understanding their current functioning at process up to biome level in its pristine and transformed state is elemental for predicting their response to changing climate and land use and the impact this will have on local up to global scale.
The purpose of this session is to unite scientists investigating the dynamics of tropical ecosystems, employing a range of remote and on-site observational, experimental, modelling, and theoretical approaches. We are particularly interested in studies evidencing/documenting how tropical biomes, at the local or regional scale, respond to human-induced disturbances and climate change. In particular, spatial gradients and temporal scales that mirror global changes. Moreover, we encourage the presentation of innovative interdisciplinary methodologies and techniques that have the potential to reshape existing paradigms, thereby paving the way for exciting new avenues of exploration.

Forest disturbance regimes (i.e. size, frequency and severity) are expected to change as global warming intensifies, thus affecting the productivity, growth and vitality of vegetation. For instance, hotter droughts are leading to widespread canopy dieback episodes rising tree mortality rates. Understanding and quantifying forest vulnerability to such disturbances and the underlying driving mechanisms is crucial to assess climate impacts and develop effective adaptation strategies.
This session will cover aspects ranging from observed and projected climate change to consequences for forest ecosystems and their assessment, spanning a range of scales, biomes and conditions. In particular, we welcome submissions on the following subjects:

• Evaluation of the effects of natural and anthropogenic disturbances on forest productivity, health and growth.
• Multidisciplinary approaches for monitoring tree vulnerability at the local, regional and global scales.
• Mapping and forecasting forest mortality and dieback phenomena under different climate and land-use scenarios.
• Modelling climate and environmental influences on forest and tree vigor and growth at different scales and considering different methods or processes (e.g., wood formation, leaf phenology, shoot growth, canopy greenness).
• Vulnerability of old-growth and mountain forests and also old trees to climate change.
• Assessing forest resilience to drought and other extreme climate events (e.g., frosts).
• Using adaptive management to buffer forest vulnerability.
• Methods and tools for decision support and adaptation support in the forestry sector considering multiple stakeholders and multifunctional perspectives.

Mycorrhizal fungi are central to the functioning of forest ecosystems, playing a critical role in ecological processes such as nutrient cycling and carbon storage. Mycorrhizal fungi enhance nutrient uptake by trees, forest productivity, influence decomposition, and they contribute to organic matter accumulation. This session aims to bring together research investigating the diverse roles and functions of mycorrhizal fungi in forest ecosystems, with a focus on ectomycorrhizal, arbuscular, and ericoid mycorrhizal associations. We will explore how mycorrhizal fungi drive ecosystem functioning in its broadest sense, and how these processes respond to environmental changes, from climate change to forest management. We welcome contributions from research conducted across various forest biomes and scales, ranging from the global to petri dish scale, encompassing observational, experimental, and modeling approaches. By fostering discussion and sharing cutting-edge research, this session aims to deepen our understanding of mycorrhizal fungi in forest ecosystems, clarify their ecological importance, and highlight the need for continued exploration in this rapidly evolving field.

Permafrost soils are one of the largest and most vulnerable terrestrial carbon and nitrogen pools. Right now, we observe that global warming is leading to drastic landscape changes and widespread permafrost thaw. Coastal erosion is aggravating, the boreal tree line is shifting northwards and tundra fires are becoming more frequent. In addition, model projections indicate that permafrost peatlands are likely to undergo rapid hydrological changes with complete permafrost losses in southernmost regions. The ongoing increase of temperature will not only enhance microbial decomposition of long-term stored soil organic matter what enhances the release of greenhouse gases, but also affect ecosystem services like the provision of traditional medicines, food, and drinking water for indigenous and local communities. Goal of this session is to understand how permafrost thaw and anthropogenic influences are affecting soil biogeochemistry and ecosystem services. We encourage submissions focusing on organic and inorganic carbon as well as on other elements such as nitrogen, phosphorus, silica, iron, mercury and others, from all parts of the global permafrost area including peatlands, mountain, inland, coastal and subsea permafrost, on all spatial scales, in the contemporary system but also in the past and future, based on field, laboratory, remote sensing and modelling work.

The last two decades have seen unprecedented progress in our understanding of the plant-soil-microbe continuum in the Arctic, however some aspects remain understudied. In recent years, it has become clear that non-growing season processes are critical in understanding year-round ecosystem and soil functioning, biogeochemical feedbacks and greenhouse gas budgets. Likewise, biotic interactions across and among various groups of soil organisms may play an underestimated role in ecosystem functioning. Both winter processes and soil biotic interactions are strongly affected by climate warming, with wide-reaching changes in the amount and phase of winter precipitation or northwards migration of hitherto absent soil ecosystem engineers. Understanding these ongoing changes is crucial to predict their future impacts on Arctic ecosystems and global biogeochemical cycles.

In this interdisciplinary session, focused on Arctic and boreal environments, we gather the latest developments in understanding the atmosphere-snow-plant-soil-microbe continuum. Our selected contributions explore how changes in the snowpack and increasing temperatures affect plants and soil organisms with a focus on resulting effects on biogeochemical cycling. This is approached across spatial scales, from earth system models to plot-level measurements, from field experiments to in vitro incubations, and even down to cells and genomes. Traditional plant and soil ecology methods as well as innovative stable isotope approaches provide insights into the mechanisms and seasonality of plant and microbial activity, priming effects, carbon exchange and nutrient cycling. Molecular methods, including environmental DNA, propose to document distribution and seasonal patterns of bacteria, micro-eukaryotes or soil fauna, and envision the modalities and impacts of their future changes. Bringing together cross-season and cross-taxa perspectives, this session will engage interdisciplinary discussions to jointly explore unknowns of Arctic terrestrial ecosystem functioning.

Peatlands contain large reservoirs of carbon and water, and are targets for both protection and restoration, serving as critical buffers against environmental change. We seek to understand responses of peatlands to natural and anthropogenic stressors and disturbances, and how these stressors could potentially shift ecosystem structure and function,. Studies are solicited involving mechanistic processes, stocks, functions, and fluxes. We welcome submissions involving experimental manipulations, anthropogenic modifications, gradient studies, and other short- and long-term environmental changes in both natural and restored peatland ecosystems. We welcome modelling studies that use theoretical approaches and observational data to understand current processes and predict future peatland trajectories. Studies are solicited which investigate any combination of overall carbon, chemical, and hydrological balance, by observing total ecosystem and soil fluxes, net ecosystem exchange and respiration, moss and vegetation turnover and succession, microbial community composition and function, and porewater and nutrient chemistry.

Drainage of peatlands both causes the loss of biodiversity and high greenhouse gas emissions. Peatland restoration for conservation purposes has been implemented for decades now, but recently the focus has been shifting towards a reconciliation of the production of biomass with ecological goals, especially the reduction of greenhouse gas (GHG) emissions, while peatland management in conservation-focussed projects increasingly has to be adapted to climate change. Management measures include, but are not limited to, productive use of wet peatlands (paludiculture), improved water management in conventional agriculture and innovative approaches in conservation-focused rewetting projects.

The human impact on peatlands is not limited to the direct effects of drainage. For centuries peatlands have been recording humanity's toxic legacy. Pollutants, such as toxic metals and metalloids, hydrocarbons, or emerging contaminants, often accumulate in peatlands, resulting in elevated pollutant levels relative to mineral soil ecosystems. This might impact both critical peatland functions, such as carbon cycling, ecohydrology, or vegetation/microbial communities and the wider landscape the peatlands are situated within. Thus, our session will feature a special section on polluted peatlands, including their management.

We invite studies addressing all types of peatland management and their impacts on GHG exchange, ecosystem services and biodiversity. Work on all spatial scales from laboratory to national level addressing biogeochemical and biological aspects as well as experimental and modelling studies are welcome. Furthermore, we invite contributions addressing policy coherence and identifying policy instruments for initiating and implementing new management practices on organic soils. Implementation and efficiency of management practices depends not only on hydrogeology and climate but also on other regional factors. Therefore, we hope to host contributions from different geographical regions where peatlands are important including boreal, temperate and tropical peatlands.

Across the globe, peatlands serve as crucial carbon (C) reservoirs and archives of past environmental changes. Deep peat deposits enable peatland palaeoecological studies to provide a long-term view of peatland evolution and resilience across all climatic zones. However, climatic change and anthropogenic pressures, for example logging, agricultural conversion, peat harvesting, drainage, forestry and resource exploration, threaten these unique ecosystems. These disturbances affect peatlands' hydrology, biodiversity, and C balance, resulting in high C loss, reduced C storage, increased greenhouse gas (GHG) emissions, loss of hydrological integrity, peat subsidence and increased wildfire risk. Recent global climate warming and shifting precipitation patterns are likely to intensify and reduce the benefits peatlands provide to people. This session welcomes contributions which explore questions related to climate, disturbance, and human impact on peatlands across different geographical regions and timescales. We strongly encourage abstracts that deepen the knowledge of all aspects of peatland ecology, evolution, and functioning, including (1) peat initiation, and peat and C accumulation and dynamics, (2) biodiversity and hydrological changes through time, (3) identification of tipping points or resilience in peatland development, (4) evidence of direct anthropogenic pressure such as peat extraction, drainage, afforestation or pollution, (5) new proxy development and calibration studies, (6) tropical peatland mapping and monitoring, (7) GHG and nutrient flux dynamics, (8) management strategies for GHG emissions mitigation, (9) valuing ancestral knowledge of peatlands, as well as other related topics. Presentations elucidating these complex relationships will contribute to understanding how peatlands responded to previous global changes and how they may develop after restoration. We look forward to insightful contributions and engaging discussions that will enrich our knowledge of peatlands in the modern era and their future trajectories.

Soils sustain complex patterns of life and act as biogeochemical reactors that produce and consume large quantity of gases, including greenhouse gases, biogenic volatile organic compounds, nitrous acid etc. Interactions with primary producer activity add further complexity to the ongoing gas exchange between soils, ecosystems and the atmosphere. Measurements of gas exchange are not only relevant for deriving emission factors for GHG accounting, for example for agricultural systems, which are central for climate mitigation actions. Such measurements are also important for understanding the underlying processes and their drivers. New technologies including automated chamber systems are developing fast and produce large, high-frequency datasets consisting of thousands of flux measurements of greenhouse gas (GHG) fluxes, carbon dioxide (CO2), methane (CH4) , and nitrous oxide (N2O), in terrestrial and aquatic ecosystems. They enable new insights into key biogeochemical cycles and their temporal and spatial regulation. However, the increased amount of data also creates a need for new methodologies for raw data processing, data curation, and data analysis to harness the complexity in these data sets. We are looking for abstracts on innovative analyses of the drivers of the gases production/consumption and transport in the ecosystems including field and laboratory studies utilising automated systems for measuring surface-atmosphere GHG exchange, novel processing and analytical approaches and modelling studies based on automated chamber data. In addition to mechanisms related to CO2, CH4 and N2O, abstracts about volatile carbon compounds produced by plants and microbes, or phenomena including noble gases such as Helium and Radon are highly welcome as well as studies on plant mediated gas transport.

Managed agricultural ecosystems, including grasslands and croplands, play a critical role in the global carbon and nitrogen cycles. They are an important source and/or sink for greenhouse gases (GHG) as well as reactive trace gases. Intensified land use and poor management have contributed to soil carbon depletion and increased GHG emissions. In contrast, sustainable management strategies offer promising pathways for enhancing carbon sequestration and mitigating nitrogen losses, as well as GHG emissions. These practices also influence the release of reactive trace gases, including ammonia, nitrogen oxides, and volatile organic compounds highlighting the need for holistic approaches that balance trade-offs and manage interactions between carbon, nitrogen, and gas fluxes.
This session, specifically focusing on grasslands and croplands, addresses experimental and modelling studies on carbon and nitrogen cycling processes and related gas fluxes at the mesocosm, field, or landscape scale. It is open to a wide range of topics including the development and application of new devices, methods, and modelling approaches, as well as field observations and process studies. Findings on comprehensive carbon, nitrogen, or GHG budgets are particularly welcome. We also encourage contributions on the applicability and overall potential of mitigation options that can inform policy recommendations for climate-smart agriculture.

Methane (CH4) and nitrous oxide (N2O) are among the most important greenhouse gases (GHG) after carbon dioxide (CO2) in accelerating global warming and deserve special attention as their concentrations increase. Forest ecosystems play an important role in the exchange of GHGs with the atmosphere. It has been shown that not only soils but also trees play a significant role in the net exchange of CH4 and N2O in forests. Trees can contribute to ecosystem exchange by uptake and transport of soil-produced CH4 and N2O to the atmosphere, by in situ production and consumption of both gases in plant tissues, and by modifying carbon and nitrogen turnover in adjacent soils. However, the contribution of these individual processes to the net ecosystem GHG exchange is still unclear and appears to depend on many aspects such as tree species (tree traits), forest ecosystem type, environmental parameters and seasonal dynamics. Soil-tree-atmosphere interactions play a crucial role in controlling the global budget of these gases.

This session aims to bring together scientists working on CH4 and N2O cycles in forest ecosystems across different climatic and hydrological ranges and scales, which is crucial for improving our understanding of CH4 and N2O exchange in forest ecosystems. We welcome contributions on production and consumption processes and mechanisms in soils and plant tissues, as well as on gas transport processes in the soil-tree-atmosphere continuum. Gas flux measurements from forest soils, cryptogams, tree stems, leaves or canopies with chamber systems or integrated ecosystem approaches (flux tower with eddy covariance, satellite or modelling) would be highly appreciated. Methodological studies closely related to the investigation of CH4 and N2O exchange in forest ecosystems are also welcome.

Solicited author:
Prof. Daniel Epron (University of Kyoto, Japan)

The study of nitrogen (N) processes in soils has a long and distinguished history. Recent research efforts have targeted the direct quantification of N turnover in the soil plant atmosphere system across scales. Nevertheless, methodological constraints, the high spatial and temporal variability of soil N transformation, and the multitude of interacting factors determining N availability and loss from soils presents significant challenges that make accurate quantification difficult, thereby limiting our quantitative understanding of the N turnover.
Although the factors controlling N turnover in soils are relatively well established under laboratory conditions, transposing these relationships to the field and landscape scales remains a significant challenge. The absence of data-sets collected in-situ impedes the validation of N processes, such as mineralization and denitrification simulated via process-based models, thereby rendering their results at field and regional scales highly uncertain. However, current ecosystem management challenges require accurate predictions of N fate to enable sustainable management that minimizes environmental losses.

We invite contributions from the following fields:
• Methodological advances in measuring and modelling of soil N processes, spanning from the micro- to the landscape scale;
• Measurements of N fluxes including specific loss pathways under field or field-like conditions with a focus on identifying controlling factors;
• Comparative studies demonstrating/evaluating novel approaches to constrain N turnover such as incubation under He/O2 atmosphere, 15N-tracer technique, N2O isotopologue approaches or other innovative methods;
• Process-based modelling of soil N processes at various scales;
• Linking nitrogen transformation rates to the function and structure of the soil microbial community.

Environmental change affects the dynamic feedbacks among plants, soil, and microbial communities, and thus strongly influences terrestrial biogeochemical cycling. In this session we address the question: What is the impact of changing environmental conditions on the plant-microbe-soil system, and what are the resulting effects on soil biogeochemistry?

We invite contributions from manipulative field experiments, observations in natural environmental gradients, and modeling studies that explore the environmental change impacts on plant-soil interactions, biogeochemical cycling of C, N, P, microbial diversity and decomposition processes, and deep-soil biogeochemistry. Submissions that adopt novel approaches, e.g. molecular, isotopic, or synthesize outputs from large-scale, field experiments focusing on plant-soil-microbe feedbacks to warming, wetting, drying and thawing are very welcome.

This is the continuation of our 2023 and 2024 successful session on the same topic and focus. We would like to continue bringing people together with this session in order to learn from each other’s studies on soils and environmental change from a global range of pedogenic and environmental settings.

Soil microbial communities are central drivers of carbon and nutrient cycling, shaping biogeochemical processes and influencing terrestrial ecosystems’ responses to Global change. However, the integration of microbial functions into biogeochemical processes often relies on simplified assumptions of cell physiology, lacking insights into actual growth dynamics and interactions within microbial groups. Building a better understanding of how microbial communities, activity and physiology respond to diverse aspects of Global change (e.g., warming, drought, land management) is crucial to predict biogeochemical processes across temporal and spatial scales.

In this session we present research exploring microbial dynamics from individuals to complex communities with a focus on their impact on soil carbon and nutrient cycling. Contributions provide a broad overview on latest developments in the field of soil microbial ecology, ranging from studies under controlled conditions with microbial isolates, to assessments of soils from various ecosystems using advanced analytical tools (e.g. -omics, microscopy, spectroscopy or isotope labeling). We present empirical and theoretical studies that investigate the resistance, resilience, and adaptation of soil microbial community structure, activity, and function, in response to single and multi-factorial climatic disturbances and research on the interactions between soil microorganisms, plants and fauna.

Stable isotopes are powerful tools for tracing water fluxes and associated nutrients in the soil-plant-atmosphere continuum. Given the complex interactions between subsurface water fluxes, plant water uptake and atmospheric drivers, new field- and laboratory-based methods should enable observations of ecohydrological processes at a high temporal and spatial resolution and with high precision and accuracy. At the same time, ecohydrological models shed new light on water and nutrient fluxes in the soil-plant-atmosphere continuum. We welcome experimental and modelling studies that present methodological developments and applications of isotope tracers to improve our process knowledge of water and nutrient fluxes between the subsurface, plants and the atmosphere, across different scales (from plant and forest stand up to the catchment scale). In our session, we aim to discuss i) innovative process-based interpretations from stable isotope data, ii) novel methods of model applications and data analysis, as well as iii) current methodological developments. We aim to foster interdisciplinary exchange between the various fields assessing ecohydrological processes using natural tracers, including research in groundwater and vadose zone hydrology, plant physiology, and ecology.

Peatlands develop in specific hydrological settings and are highly sensitive to changes in hydrological conditions and climate. For example, both peat hydrological properties and peatland greenhouse gas balance can change drastically after disturbances such as drainage, permafrost thaw, or mechanical compaction. Hydrological conditions are also a key control for a number of the ecosystem services offered or regulated by peatlands, including biodiversity, carbon storage, and nutrient retention. In addition, the role of pristine and disturbed peatlands in flood retention, support of low flows and regional climate remains debated. As hydrological and biotic processes in peatlands are strongly coupled, predicting the eco-hydrological effects of climate change, degradation, and restoration on peatland ecosystem responses—including greenhouse gas emissions—is a demanding task for the peatland community.

This session addresses peatland hydrology and its interaction with ecosystem processes in all latitudes. We especially encourage papers on permafrost and tropical peatlands for which field studies are scarce and inclusion into Earth system models is largely pending. We invite submissions on: (1) hydrological processes operating in all types of peatlands (pristine, disturbed, degraded, drained, managed, rehabilitated or re-wetted) in boreal, temperate, and tropical latitudes; and (2) the first-order control of peatland hydrology on all kinds of peatland functions.

We aim to advance the transfer of knowledge and methods and welcome laboratory, field, remote sensing, and modeling studies on hydrological, hydrochemical, biogeochemical, ecohydrological or geophysical topics, as well as ecosystem service assessments.

Tree rings are one of nature’s most versatile archives, providing insight into past environmental conditions at annual and intra-annual resolution and from local to global scales. Besides being valued proxies for historical climate, tree rings are also important indicators of plant physiological responses to changing environments and of long-term ecological processes. In this broad context we welcome contributions using one or more of the following approaches to either study the impact of environmental change on the growth and physiology of trees and forest ecosystems, or to assess and reconstruct past environmental change: (i) dendrochronological methods including studies based on tree-ring width, MXD or Blue Intensity, (ii) stable isotopes in tree rings and related plant compounds, (iii) dendrochemistry, (iv) quantitative wood anatomy, (v) ecophysiological data analyses, and (vi) mechanistic modeling, all across temporal and spatial scales.

The interaction between the soil-plant-atmosphere compartments and human activities is of paramount importance for the sustainable management and preservation of ecosystem functions and services. The functionality and services of terrestrial ecosystems are threatened by global climate change and human activities. The complexity and comprehensiveness of the impacts have so far proven challenging to assess due to the limitations of simplified experimental approaches and long-term observations, which often focus on a limited number of response variables.
Experimental systems such as lysimeters or ecotrons provide continuous, high-resolution and high-quality observations of detailed time series, which are crucial for a more accurate determination of the Earth's ecosystem services and functions and for promoting interdisciplinary ecosystem research.
This session will mainly focus on the diversity of ecosystem research using research platforms of lysimeters and ecotrons. We would also like to address the challenges of modelling ecosystem processes, comparison of metrics with other in situ instruments, upscaling approaches from such platforms to larger scales, validation studies (e.g. remote sensing), but also new developments in the field of lysimetry and further development of processing algorithms for interpretation of high temporal resolution lysimeter/ecotron weight data. We welcome contributions that (1) present novelties in the field of lysimeters, (2) assess and compare the functioning and services of terrestrial ecosystems, particularly in relation to climate change, (3) focus on water and nutrient transport processes (4) and greenhouse gases within the soil-plant-atmosphere continuum, (5) develop new techniques for the analysis of lysimeter and ecotron observations, (6) include ecosystem or hydrological modelling approaches using in situ observations from lysimeters or ecotrons.

The session invites experimentalists and modelers working on air-land interactions from local to regional scales, in vegetated and/or urban systems. The program is open to a wide range of innovative studies in micrometeorology and related atmospheric and remote sensing disciplines. The topics may include the development of new observational devices, measurement techniques, experimental designs, data analysis methods, as well as novel findings on surface layer theory and parametrization, including local and non-local processes. Theory-based contributions may encompass soil-vegetation-atmosphere transport, internal boundary-layer theories, and flux footprint analyses. Of particular interest are synergistic studies employing experimental data, parametrizations, and models addressing energy and trace gas fluxes (of inert and reactive species) as well as water, carbon dioxide and other GHG fluxes. We focus on addressing outstanding problems in land surface boundary layer descriptions such as complex terrain, effects of horizontal heterogeneity on sub-meso-scale transport processes, energy balance closure, coupling/decoupling, stable stratification and night time fluxes, dynamic interactions with atmosphere, and plants (in canopy and above canopy) and soils.

The forest floor is the most reactive part of forest soils with much faster biogeochemical turnover than the mineral soil. Owing to its high reactivity and to its position as interface between the aboveground and belowground parts of the ecosystem, it is more responsive to climatic or management changes of forest ecosystems than the mineral soil. Currently, temperate European forests undergo significant changes, mainly induced by climate change, eutrophication, species composition and management. Negative consequences for forest floor functioning are documented, potentially impacting forest soils as a whole. Yet, forest floors are often not considered adequately and therefore, we are neither in a position to assess the current state of functioning or predict future developments, nor can we estimate consequences for mineral soils and forest ecosystem health.
With this session we encourage interdisciplinary exchange addressing the causal links between controls, properties, and functioning of forest floors. We aim to elucidate forest floor vulnerability to climate change and to identify biological, chemical, morphological and physical forest floor properties, serving as indicators for forest soil health. We encourage contributions that integrate multiple scientific disciplines and approaches to draw a holistic picture of forest floor functioning at different levels from micro, to soil profile to the landscape scale.

Coastal vegetated environments are among the most carbon-dense ecosystems on Earth and are often collectively referred to as Blue Carbon habitats. These habitats include salt marshes, mangrove forests, and seagrass meadows. They play a variety of important roles such as biodiversity support and coastal protection, while also providing nature-based solutions contributing to the mitigation of anthropogenic carbon dioxide emissions.

Coastal vegetated ecosystems are under increasing pressure globally due to climate and sea-level change, as well as local anthropogenic activities, which can disrupt their resilience and their carbon balance. There is a pressing need to understand and address these global change impacts and pressures upon carbon cycling in these ecosystems, as well as the disruption to their overall ecosystem dynamics. A better understanding of the feedback loops between sediment carbon and vegetation, the intricate exchanges of different forms of carbon between the atmosphere, sediment, and water

BG4.2 | Session description

The coastal ocean has been increasingly recognized as a dynamic component for many biogeochemical cycles such as nutrients, oxygen, and the global carbon cycle. This session aims at fostering our understanding of the roles of coastal environments and of exchange and transport processes, both natural or perturbed, along the terrestrial / coastal sea / open ocean continuum in global biogeochemical cycles. During the session recent advancements in the field of coastal, shelf and estuarine biogeochemistry will be discussed. Contributions focusing on carbon and nutrient and all other natural and anthropogenically impacted element's cycles in coastal, shelf, shelf break and estuarine environments, both pelagic and sedimentary, are invited.

This session is multidisciplinary and is open to observational, experimental, modelling and theoretical studies in order to promote the dialogue. The session will comprise subsections on coastal carbon storage, on benthic biogeochemical processes, microplastics and suspended particulate matter dynamics and on biological and ecological experimental approaches in marine and estuarine biogeosciences.

Our ability to understand biogeochemical cycles of carbon, nitrogen and phosphorus and other elements in aquatic ecosystems as well as biotic evolution and ecosystem functioning has evolved enormously thanks to advancements in in situ sensor measurements, laboratory techniques and predictive models. The aim of this session is to demonstrate how this methodological advancement improves our understanding of coupled hydrological, biogeochemical and ecological processes in aquatic environments and how it decodes faunal and ecosystem functional responses. In particular, our session focuses on improving the identification and quantification of the sources, delivery pathways, transformations and environmental fate of carbon and organic matter, nutrients, sediments and emerging contaminants in aquatic environments. Additional emphasis will be placed on biogeochemical interactions affecting aquatic organisms. In this multidisciplinary session, we welcome presentations on applications of novel techniques to improve our understanding of aquatic environments, , their biotic evolution, and robust data-driven and modelling approaches for advanced processing of aquatic biogeochemical data. As hydrological, biogeochemical, and ecological processes undergo accelerated change, this session welcomes also studies presenting approaches and tools to monitor, model, and predict water quality and sensitivity of aquatic ecosystems to global change and human disturbance.

The session is co-sponsored by JpGU.

Our capacity to estimate regional and global budgets of greenhouse gases (GHG, including CO2, CH4 and N2O) from aquatic ecosystems has been significantly improved during the past decade, thanks to the substantial increase in field measurements. However, global estimates of these fluxes remain highly uncertain. Moreover, compared with terrestrial ecosystems, the field of aquatic GHG research is still young and the mechanisms behind the spatiotemporal patterns and variability of GHG concentrations and fluxes in aquatic ecosystems are not sufficiently understood, constraining model development. Therefore, to improve our estimations and understanding of regional and global GHG budgets from aquatic ecosystems, this session welcomes contributions on e.g.:
1) Field observations of GHG dynamics and fluxes in aquatic ecosystems, both freshwater and marine systems.
2) Experiments revealing physicochemical or biological processes or factors of relevance for GHG production, consumption, transport, emission, or uptake.
3) Model development or simulation efforts to estimate GHG dynamics and fluxes across different spatial and temporal scales along the aquatic continuum.
Contributions providing additional perspectives of relevance for aquatic GHG cycling and fluxes are also of interest.

Wetland ecosystems provide essential services for the subsistence of life on Earth; however, these ecosystems face constant external threats that affect and change their natural processes and dynamics.

Significant knowledge gaps exist on multiple aspects, components, and interactions of wetlands worldwide. Multitemporal Earth observations offer an excellent opportunity to address these knowledge gaps and are sometimes the only source of information in remote and non-instrumented areas.

This session focuses on studies using Earth observation data (from passive and active sensors) to explore and understand wetland dynamics, processes, and services, as well as their broader connections with other elements of the landscape. It encompasses investigations into various components and processes of wetland ecosystems, such as (but not limited to) water dynamics, vegetation changes, disturbances, soil moisture, biodiversity, across a range of wetland types (e.g., marshes, swamps, fens, bogs, peatlands, lakes, ponds, coastal wetlands).

The session also encourages studies utilizing multi-sensor approaches, as well as machine learning, deep learning, and artificial intelligence technologies, to develop innovative solutions for wetland monitoring, conservation, and restoration.

Continental shelf sea sediments play a crucial role in the global carbon cycle due to their vast spatial extent, yet their relative importance in storing organic carbon and the possible impacts of human activities on their carbon storage potential remain subjects of debate. Organic carbon storage in these sediments is highly spatially variable, driven by a complex interplay of physical, chemical, and biological processes. In addition, marine sediments are under increasing pressure from anthropogenic activities and climate forcing.
Despite advancements in sedimentary Blue Carbon research, knowledge gaps persist regarding the spatial variability of organic carbon accumulation rates, long-term accumulation and burial processes, the role of organic carbon sources or reactivity in forming stocks within continental shelf sediments, and the influence of human activities on these parameters. Human impacts include, but are not limited to: bottom-contacting fisheries, marine aggregate mining, offshore construction, material dumping, and coastal protection.
The proposed session aims to bring together a diverse group of researchers to explore factors influencing sedimentary Blue Carbon accumulation and storage in continental shelf seas, informing policy and management strategies for carbon sequestration and climate change mitigation.

This session invites researchers working on:
(i) Processes that influence organic carbon accumulation, such as sedimentation rate, post-depositional degradation, and human activities. We particularly welcome talks that address knowledge gaps regarding organic carbon burial and the link to biological processing and biodiversity.
(ii) The source and composition of stored organic carbon, including the differentiation between labile and refractory fractions.
(iii) The availability and spatial coverage of data supporting organic carbon stock assessments and estimates of transfer efficiency.
(iv) The mechanisms of organic carbon deposition are an important consideration, and we welcome discussion on how hydrodynamic conditions affect the deposition of fine, organic carbon-rich material on the seabed.
(v) The use of advanced techniques for mapping sedimentary Blue Carbon stocks, with an emphasis on the importance of remote sensing, modelling, and machine learning.
(vi) The response of stored organic carbon to human pressures such as trawling, infrastructure life cycles and climate change itself, using observational or modelling approaches.

The ocean has stored vast amounts of carbon and heat due to anthropogenic CO2 emissions and climate change. We need to understand the processes driving this storage, that is uptake from the atmosphere, transfer to the ocean interior, redistribution within the ocean, and return to the ocean surface and the atmosphere. Also, ocean storage of carbon and heat are not independent: oceanic CO2 storage affects atmospheric CO2 levels, thereby atmospheric and oceanic warming. Ocean warming importantly, besides others changes ocean circulation and mixing which influences further uptake of both anthropogenic heat and carbon, and also perturbs the preindustrial ocean-atmosphere exchange of both, heat and carbon.

This session invites observational, numerical modeling and analytical studies that enhance the process understanding of ocean storage of carbon and/or heat under various climate scenarios: the contemporary situation of net-positive CO2 emissions and global warming, as well as future scenarios involving the gradual phasing out of CO2 emissions or a warming overshoot followed by net-negative emissions and global cooling. We also seek studies that explore the similarities and differences between ocean storage of carbon and heat, and how ocean uptake —and potential future release— affect climate.

Solicited author: Roland Séférian

Covering 70% of the Earth's surface, the sea surface microlayer (SML) is recognized as a critical boundary between the ocean and atmosphere. Its unique position places the SML at the center of various global processes in biogeochemistry and climate science. This session welcomes recent advancements in understanding the SML's distinctive chemical, biological, and physical characteristics, with a focus on understanding the underlying mechanisms of processes. Particular emphasis is given to the SML's function in modulating air-sea exchanges of heat, freshwater, gases, particles, and biota, but also exchange processes between the SML and the underlying bulk water, which are crucial for a more comprehensive understanding.. The concept of the SML as a biogeochemical reactor is also a central theme in the session to highlight the roles of environmental interfaces in marine biogeochemistry. Of further interest is the accumulation of pollutants such as hydrocarbons, microplastics, soot and pharmaceuticals, but also pathogenic microorganisms and viruses. In this context, the formation of (bio)aerosols as well as deposition processes play a role. To advance future studies, new observational, experimental and genomic approaches to the study of SML are particularly welcome. This multidisciplinary session welcomes participants from all research fields interested in the SML and its impact on surrounding environments. The session aims to bring together insights and findings from field observations, laboratory experiments, and models. By exploring the interplay between physical, chemical, and microbiological processes at the ocean-atmosphere interface, we seek to further develop a holistic perspective and foster new collaborations across research disciplines.

Ocean-atmosphere chemical flux exchanges have significant impacts on global biogeochemistry and climate. This session focuses on new research in the following areas: air-sea fluxes of greenhouse gases (e.g., CO2, CH4, N2O), atmospheric deposition of nutrients (e.g., nitrogen, phosphorus, iron) and its impact on ocean biological systems, the influence of ocean emissions of reactive gases and aerosols on atmospheric chemistry and climate (e.g., dimethyl-sulfide (DMS), marine organic compounds, halogenated species), and on the important biogeochemistry-climate feedback loops in the ocean-atmosphere system as well as future changes in these fluxes in response to anthropogenic and climate stressors. The session has long-standing links to the Surface Ocean Lower Atmosphere Study (SOLAS; https://www.solas-int.org/) and GESAMP Working Group 38 on atmospheric input of chemicals to the ocean (http://www.gesamp.org/work/groups/38). We welcome submissions from all remit areas of these programs, and from a range of analysis approaches: field measurements, remote sensing, laboratory studies, and atmospheric and oceanic numerical models.

This year we particularly welcome contributions on the following specialist themes:
(a) greenhouse gas emissions and cycling from coastal zones, with particular focus on the impacts of nutrient and pollutant transport across the land-ocean continuum (e.g. via riverine input, glacier meltwater runoff, submarine groundwater discharge), as well as benthic-pelagic coupling for greenhouse gas budgets in regional and global scales; and
(b) the role of the Sea-Surface Microlayer (SML) as a biofilm environment and direct air-sea- interface, and its influence on deposition and emission fluxes of gases, aerosols, and particulates between the ocean and atmosphere.

This session aims to bring together a diverse group of scientists who are interested in how life and planetary processes have co-evolved over geological time. This includes studies of how paleoenvironments have contributed to biological evolution and vice versa, linking fossil records to paleo-Earth processes and the influence of tectonic and magmatic processes on the evolution of climate and life. As an inherently multi-disciplinary subject, we aspire to better understand the complex coupling of biogeochemical cycles and life, the links between mass extinctions and their causal geological events, how fossil records shed light on ecosystem drivers over deep time, and how tectono-geomorphic processes impact biodiversity patterns at global or local scales. We aim to understand our planet and its biosphere through both observation- and modelling-based studies. We also invite contributions on general exoplanet-life co-evolution.

This session is co-organized by COST Action CA23150 - pan-EUROpean BIoGeodynamics network (EUROBIG)

Quaternary climate variability is characterised by changes in the carbon cycle on all timescales from seasonal to orbital (glacial-interglacial cycles), manifesting in large variations in the atmospheric CO2 concentrations. Studying the natural carbon cycle variability is essential to address the current challenges of climate change. However, interpreting past changes remains difficult due to the complex and poorly understood interactions between the different reservoirs of the climate system (ocean, atmosphere, biosphere, lithosphere, cryosphere) and their impacts on the carbon cycle. Among these are impacts of changes in oceanic circulation and productivity, and interactions between vegetation composition, wildfire regimes and atmospheric conditions. Paleo-environmental proxy records and Earth system models provide insights into natural variations in atmosphere-carbon exchange, ocean carbon storage, and vegetation-fire-climate interactions. In particular, they can inform on changed dynamics due to major climatic transitions during the Quaternary, and on changes due to anthropogenic climate change and human land management.

We invite contributions that focus on vegetation, wildfire and ocean dynamics during the Quaternary and their interactions with climate to understand changes in the continental and oceanic carbon cycle. This includes: (a) regional and global-scale reconstructions of fire regimes and vegetation cover from paleo-environmental data, (b) multi-tracer analyses (e.g., micropaleontology, geochemistry) of marine sediment cores to reconstruct variations in carbon stocks and fluxes between the atmosphere and the ocean, (c) the development and application of innovative proxies and archives, (d) Earth system model simulations and comparisons with proxy records, and (e) studies that can inform future land management policies.

Speleothems are key terrestrial archives of regional to global paleoclimatic and paleoenvironmental changes on sub-seasonal to orbital scales. They provide high temporally resolved records which can be accurately and precisely dated using a variety of proxies such as stable O and C isotopes and trace elements. Recent efforts have seen the rise in more non-traditional proxies such as fluid inclusion water isotopes, organic biomarkers, pollen, dead carbon fraction etc.. This advancement towards quantitative reconstructions of past precipitation, temperature, or other environmental variables and climate patterns, are key variables for data-model comparisons and evaluation. Beyond this, caves and karst areas additionally host an enormous suite of other valuable archives such as cave ice, cryogenic carbonates, clastic sediments, tufa, or travertine sequences which complement the terrestrial palaeorecord, and are often associated with important fossils or archaeological findings.
This session aims to integrate recent developments in the field, and invites submissions from a broad range of cave- and karst-related studies from orbital to sub-seasonal timescales.
In particular we welcome contributions from:
(1) (quantitative) reconstructions of past climatic and environmental variables to reconstruct precipitation, vegetation, fire frequency, temperature etc. across different climate zones,
(2) field- and lab-based developments of process-based methods to improve our application of proxy variables,
(3) process and proxy-system model studies as well as integrated research developing and using databases such as SISAL (Speleothem Isotope Synthesis and AnaLysis).
We further welcome advancements in related and/or interdisciplinary areas, which pave the way towards robust (quantitative) interpretations of proxy time series, improve the understanding of proxy-relevant processes, or enable regional-to-global and seasonal-to-orbital scale analyses of the relationships between proxies and environmental parameters. In addition, research contributing to current international co-ordinated activities, such as the PAGES working group on Speleothem Isotopes Synthesis and AnaLysis (SISAL) and others are welcome.

Sedimentary archives can be found across diverse environments worldwide, allowing investigation and disentanglement of past environmental processes over different setting. However, one key limitation in the investigation of such records is deciphering the complexity of how the different forcings acting in a natural system are manifested in the environment and consequently propagated into the studied archives. Interpretations derived from any sedimentary archive thus depend on a our understanding of the surrounding natural system itself and its web of feedbacks, the investigated sedimentary record, and the utilized proxies. Such interpretations often call for the integration of different disciplines, the development of new tools for sampling, novel laboratory methodologies and modelling. These studies need to integrate both modern and recent observations as well as reconciling these with numerical models to improve our predictions of coastal evolution in the future. Combining vast datasets from remote sensing, habitat mapping, geophysical surveys, and in situ monitoring, with advanced analytics and numerical models, provides a holistic view of coastal evolution.

For this session we welcome any contribution that integrates sedimentological, geochemical, biological, and geochronological methods, as well as modelling approaches, novel laboratory experiments and monitoring, for the interpretation of sedimentary systems, with a special focus on mechanism-oriented interpretation. Contributions that either focus on the development and calibration of novel proxies, analytical approaches (either destructive or non-destructive) and data analysis (statistics, machine learning, AI), or present interesting case studies, are welcome as well.

Minerals formed under surface and burial conditions serve as invaluable archives of Earth’s environmental and geological history. This session explores the field of mineralization and diagenesis, from surface conditions to deep burial, emphasizing the integration of biological, chemical, and physical mechanisms. We invite contributions from a wide range of research topics, including studies on the effects of diagenesis on mineralogy, fluid composition, and mechanical properties, geochemical and isotopic records as environmental archives, and biotic and abiotic mineral formation.

Micropaleontological data, such as assemblage composition, morphology, and evolutionary patterns, provide unique insights into the dynamics and tipping points of past environments and climate through changes in the fossil record. Micropaleontology lies at the heart of biostratigraphy and provides a fundamental tool for reconstructing and stratigraphically constraining past changes in the Earth system. Our session aims to gather a broad spectrum of micropaleontologists to showcase recent advances in applying micropaleontological data in paleoenvironmental, paleoclimatological, and stratigraphic research in both marine and terrestrial settings.
We invite contributions from the field of micropaleontology that focus on the development and application of microfossils (including, but not limited to, coccolithophores, diatoms, dinoflagellates, foraminifera, ostracods, radiolarians, pollen) as proxies for paleoenvironmental and paleoclimatological reconstructions and tools for stratigraphic correlation. We particularly encourage the submission of multi-proxy approaches, merging micropaleontological information with geochemical and paleobiological information. The application of microfossils as stratigraphic markers and advancing multivariate statistical techniques with a focus on microfossil assemblages is encouraged.

The Quaternary Period (last 2.6 million years) is characterized by frequent and abrupt climate swings and rapid environmental change. Studying these changes requires accurate and precise dating methods that can be effectively applied to environmental archives. Different methods or a combination of various dating techniques can be used depending on the archive, time range, and research question. Varve counting and dendrochronology allow for the construction of high-resolution chronologies. In contrast, radiometric methods (radiocarbon, cosmogenic in-situ, U-Th) and luminescence dating provide independent anchors for chronologies that span longer timescales. We particularly welcome contributions that aim to (1) reduce, quantify, and express dating uncertainties in any dating method, including high-resolution radiocarbon approaches; (2) use established geochronological methods to answer new questions; (3) use new methods to address longstanding issues, or; (4) combine different chronometric techniques for improved results, including the analysis of chronological datasets with novel methods, e.g., Bayesian age-depth modeling. Applications may aim to understand long-term landscape evolution, quantify rates of geomorphological processes, or provide chronologies for records of climate change and anthropogenic effects on Earth's system.

The geological record provides insight into how climate processes operate and evolve in response to different than modern boundary conditions and forcings. Understanding deep-time climate evolution is paramount to progressing on understanding fundamental questions of Earth System feedbacks and sensitivity to perturbations, such as the behaviour of the climate system and carbon cycle under elevated atmospheric CO2 levels—relative to the Quaternary—, or the existence of climatic tipping points and thresholds. In recent years, geochemical techniques and Earth System Models complexity have been greatly improved and several international projects on deep-time climates (DeepMIP, MioMIP, PlioMIP) have been initiated, helping to bridge the gap between palaeoclimate modelling and data communities. This session invites work on deep-time climate, Earth System model simulations and proxy-based reconstructions from the Cambrian to the Pliocene. We especially encourage submissions featuring palaeoenvironmental reconstructions, palaeoclimate and carbon cycle modelling, and the integration of CO2 and (hydro)climate proxies and models of any complexity.

Marine and terrestrial ecosystems have been affected by anthropogenic stressors (e.g., biological invasions, eutrophication, climate change, land use change, and overexploitation) for centuries to millennia. By covering only recent decades, scientific surveys and monitoring are insufficient to fully assess human impacts and the long-term ecosystem status. Predicting future changes and effectively restoring degraded communities without knowing past species and ecosystem responses and historical baselines is thus challenging. The fossil record and other palaeoecological archives (e.g., biogeochemical or isotopic signatures of sediment cores and/or archaeological middens) provide long-term data that document past environmental disturbances and their effects on organisms and ecosystem structure (e.g., body size changes, taxonomic and functional composition, diversity patterns). In addition, deep-time palaeoecological records provide analogue scenarios for present-day environmental and climate perturbations, capturing extirpations and recovery dynamics of ecosystems on evolutionary timescales.
Therefore, this session will explore how interdisciplinary approaches to palaeoecological records can enhance the interpretation of the temporal dynamics of past (deep-time and Quaternary) ecosystems and thus provide context and guidance for the near-future dynamics of modern ecosystems. We will address major challenges of interpreting palaeontological and palaeoecological records. For example, a proper understanding of the spatial and temporal resolution of palaeo-archives is needed to reconstruct long-term ecosystem dynamics and historical baselines. It is also crucial to know how the ecological and environmental information preserved in the fossil record is affected by taphonomic biases. Despite these challenges, palaeoecological records are highly useful for conservation and reconstruction efforts. This will be demonstrated by case studies using a wide range of tools and analytical approaches from palaeontology, palaeoecology, stratigraphy, geochemistry, historical ecology, and archaeology.

Environmental DNA (eDNA) metabarcoding is a noninvasive method to detect biodiversity in a variety of environments that has many exciting applications for geosciences. In this short course, we introduce eDNA metabarcoding to a geoscience audience and present potential research applications.

Soil organisms are the principal actors in key soil functions that underlie ecosystem services such as primary productivity, nutrient cycling, and carbon transformations. Linking soil community characteristics to soil and ecosystem functioning holds great promise for guiding conservation efforts in natural systems and supporting sustainable agriculture. Characterizing soil microbial communities requires a wide focus: growth and anabolism rely on carbon, energy and nutrients (e.g., N and P) in appropriate stoichiometric relationships, but also depend on who is where (biodiversity), who does what (activity and function), and how microbial death processes create necromass for subsequent transformation (elemental cycles). Various sources of organic matter provide raw materials, which are converted into new cellular growth, microbial storage compounds, microbial products or greenhouse gases such as CO2. This session integrates empirical and modelling insights to elucidate the energy and matter flows driven by soil microbial metabolism and biodiversity reflected in functional ecological processes in both natural and agricultural studies.

We aim to stimulate interdisciplinary discussions to advance our understanding of soil biology at different scales, from the mechanistic understanding of biogeochemical processes to ecosystem functioning.

We are excited to have Stefano Manzoni (Stockholm University) as an invited speaker for the session.

Across our planet, microorganisms - including bacteria, archaea, viruses, microalgae, and fungi - play vital roles in nutrient cycling and ecological balance. Airborne microbial cells that were emitted from marine and terrestrial surfaces are transported and redistributed in the atmosphere on various temporal and spatial scales.
While extensive research has been dedicated to understand microbial communities in the cryo-, litho-, hydro-, and phyllo-spheres, studies on atmospheric microorganisms have been limited to describing their abundance, diversity, and potential climatic and sanitary implications. However, the atmosphere hosts living cells that take part in and are affected by biological, chemical, and physical processes while airborne, contributing to the intricate web of life on our planet.
The continuous exchange of microorganisms between surface habitats and the air makes the atmosphere an important, highly dynamic component of the microbial life cycle that effects biogeochemical cycles and chemical composition.
Thus, to gain a more complete understanding of the planet’s microbiome, it is important to identify atmospheric chemical, physical and biological factors that shape and modulate airborne microbial populations, diversity, and functioning. Such factors include, e.g., emission/deposition and transport processes, exposure to stress factors (e.g., oxidative or osmotic stress) and other intrinsic biological traits of airborne microorganisms which may contribute to their survival and activity.
This session will provide an interdisciplinary platform for atmospheric scientists, biogeoscientists, microbial ecologists and other researchers which are concerned with (i) the transport processes of living microorganisms, (ii) microbial processes in the atmosphere and their feedbacks on the Earth surface (water, soil, vegetation, ice), and (iii) atmospheric factors, processes and conditions that affect atmospheric microbial diversity, concentrations, survival, and functioning. We particularly encourage contributions that lead to a more comprehensive characterization of the microbiome and its interactions with the atmosphere and Earth’ surfaces.

Methane is of utmost importance as a trace gas in the atmosphere and we know that most of the environmental methane is produced - and also consumed in sediments and the water column of marine and lacustrine systems.
But…, understanding methane dynamics in the aquatic realm is still a major scientific challenge because it is governed by a vast diversity of geological, oceanographic/limnological, biological factors and anthropogenic causes.
In this session we will discuss controls on methane dynamics in marine and freshwater systems at present, in the geological past, and in future scenarios. Within this overarching theme we welcome contributions related to the following topics:

- methane formation: from water-rock interactions to petroleum systems and microbial methanogenesis
- methane transport: from subsurface fluid flow to bubble and diffusive transport mechanisms and fluxes.
- methane seepage and mud volcanoes
- anthropogenic factors: from hydrocarbon exploitation to energy infrastructure and hydraulic structures
- methane sinks: from microbes, biogeochemical pathways and kinetics to physicochemical processes and gas hydrate formation
- timescales: variations on diel, seasonal, and geological time scales
- methane-derived carbonates, microbe-mineral interactions, and molecular/micro/macro fossils
- methane releases in the geological past, consequences and climate change

The first half of Earth’s history (Hadean to Paleoproterozoic) laid the foundations for the planet we know today. But how and why it differed and how and why it evolved remain enduring questions.
In this session, we encourage the presentation of new approaches that improve our understanding on the formation, structure, and evolution of the early Earth ranging from the mantle and lithosphere to the atmosphere, oceans and biosphere, and interactions between these reservoirs.
This session aims to bring together scientists from a large range of disciplines to provide an interdisciplinary and comprehensive overview of the field. This includes, but is not limited to, fields such as early mantle dynamics, the formation, evolution and destruction of the early crust and lithosphere, early surface environments and the evolution of the early biosphere, mineral deposits, and how possible tectonic regimes impacted across the early Earth system.

A variety of geophysical and geological observational techniques are now mature enough to provide valuable insights into the influence that mantle convection has on Earth' surface and its core. Current challenges include the need to reconcile different spatial resolutions between models and observations, uneven data coverage and the determination of appropriate sampling and simulation scales. This session will provide a holistic view of the influence of mantle convection on core dynamics and surface expressions from geodetic to geological time scales using multi-disciplinary methods, including (but not limited to): geodetic, geophysical, geological, long-term evolution of the geomagnetic field, Earth's core dynamics magnetism and the seismic imaging of mantle convective processes, as well as numerical modeling.

Our session will provide rich opportunities for presenters and attendees from a range of disciplines, demographics, and stages of their scientific career to engage in this exciting and multidisciplinary problem in Earth science.

Mid-oceanic ridges (MORs) provide the unique opportunity to study two of the three plate boundaries: divergent plate boundaries along and across the ridge axis and tectonically dominated movements (e.g., transform faults). Our understanding of the active processes building and modifying the oceanic lithosphere has increased over the past 20 years due to advances in deep-sea research technologies and analytical and numerical modeling techniques. Increasingly, the processes inferred from the present oceanic lithosphere are also transferred into those operating in the Proterozoic and Archean. Yet, the relative role of magmatic, tectonic, and hydrothermal processes and their interaction in the formation and accretion of the oceanic lithosphere at the ridge, especially at slow and ultra-slow spreading ridges and along transform faults, remains poorly constrained. Transform faults and their extension into fracture zones have previously been considered as relatively cold and magmatically inactive; however, evidence for magmatism has recently emerged. The complex network of faults associated provide ideal pathways for hydrothermal percolation into the Earth’s lithosphere and may therefore play a significant role in the chemical and the thermal budget of the planet, as well as in the chemical exchange with the ocean (e.g., nutrients). Yet, little is known about fluid circulation in the lithosphere in these ultraslow settings.
This session objective is to favor scientific exchange across all disciplines and to share recent knowledge acquired along mid-oceanic ridge axes, transform faults, and fracture zones. We particularly welcome studies using modern deep-sea high-resolution techniques. The session also welcome contributions dealing with recent discoveries in hydrothermal systems, and which integrate geophysical, geochemical, petrological and geological data with numerical modeling tools.