Fire is the primary terrestrial ecosystem disturbance globally and a critical Earth system process. Fire-related research is rapidly expanding across disciplines and sectors, reflecting the pressing need to deepen our understanding of fire phenomena. This need will likely grow as future fire activity increases. This session invites contributions that investigate the role of fire within the Earth system across any temporal and spatial 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 that deepen our comprehension of 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) spatial and temporal 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 to keep climate warming well below two degrees. This extraordinary challenge requires a dramatic improvement of current scientific capabilities to estimate the budgets and their trends of greenhouse gases (GHG) at regional scale, and how they link up to the global growth rates of the major GHGs (N2O, CH4 and CO2).
This session aims to bring together studies that seek to quantify global and regional budgets, trends and variability of major GHG (N2O, CH4 and CO2), as well as to understand 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, and atmospheric inverse modeling. We encourage contributions from the REgional Carbon Cycle Assessment and Processes phase 2 (RECCAP2), as well as studies 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.

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 has depleted geological 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 on the magnitude and timing of P fluxes into aquatic ecosystems, influencing their trophic state. Burial in sediments returns P to the geological sink, eventually forming economically viable P deposits. Throughout the P cycle, redox conditions play a key role in transformations and mobility of P.

This interdisciplinary session, now celebrating its 10th anniversary at EGU, invites contributions to the study of P from across the geosciences, and aims to continue fostering 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 forests, soils and groundwater, through lakes, rivers and estuaries, to oceans, marine sediments and geological P deposits. We welcome studies of both past and present P cycling, with a focus on novel techniques and approaches.

Spatial and temporal changes in environmental conditions over billions of years have driven the evolution of diverse microbial, fungal and plant species that have shaped the ecosystems, atmosphere and climate of our Earth system. Understanding the function and resilience of organisms and our biomes in response to climatic change and their complex feedbacks requires knowledge of its component parts and their interactions. Technological innovations in the measurement and interpretation of expansive and detailed ‘meta-omics’ datasets are poised to reveal mechanistic understanding across diverse organisms, scales and ‘spheres’ as well as facilitating a new generation of modelling tools to predict ecosystem function. In this special thematic BG session we gather ecologists, biogeochemists and evolutionary biologists together to examine the -omic tool-boxes now available to examine and interpret the form and function of organisms and communities, and the efforts now being made to integrate this knowledge across biological and temporal scales. By combining eco-evolutionary knowledge with ecosystem-level concepts of community traits and resilience we hope to develop and encourage future BG sessions that use integrated ‘omics’ and ‘meta-omics’ approaches with other biogeoscience techniques to provide a deeper mechanistic understanding.

Solicited Speakers Information:

Scott Saleska is Professor of Ecology and Evolutionary Biology at the University of Arizona and where he is co-Director of BRIDGES, an NSF-funded graduate training program to Build Resources for InterDisciplinary training in Genomic and Ecosystem Sciences; and Science Director of the Landscape Evolution Observatory at Biosphere 2.

Chris Bowler is research director at the CNRS and director of the Plant and Algae Genomics Laboratory at the Institut de biologie de l'École normale supérieure in Paris.

Linnea Honeker is a postdoctoral researcher at Lawrence Livermore National Laboratory, specializing in soil microbiome bioinformatics.

Abraham Nqabutho Dabengwa is a Postdoctoral Researcher at the Evolutionary Studies Institute, University of the Witwatersrand, South Africa.

Anna Mankowski is a marine microbiologist and bioinformatician working as a postdoctoral fellow at the European Molecular Biology Laboratory in Heidelberg, Germany.

Luciana Chavez Rodriguez is a soil modeler working as a Postdoctoral Scholar at the University of California, Irvine, in the Department of Ecology and Evolutionary Biology.

Kristen Kuesel is a Full Professor of Aquatic Geomicrobiology at the Friedrich Schiller University in Jena, Germany, and one of the founding directors of the German Centre for Integrative Biodiversity Research (iDiv).

Jenni Hultman is a senior scientist at the Natural Resources Institute Finland (LUKE).

Alex Chase is a member of faculty at the Southern Methodist University in the Department of Earth Sciences, Texas, USA.

Thomas Dussarrat is a postdoctoral researcher at the Bielefeld University, Germany.

Laura Meredith is an Associate Professor of Ecosystem Genomics at the University of Arizona, USA.

Pierre Amato is a researcher at the CNRS, Clermont-Ferrand, France.

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 are strongly affecting Earth’s atmospheric composition, air quality, global warming, climate change and human health. 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. 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.

Tropical ecosystems are biomes of global significance due to their large biodiversity, carbon storage capacity, and their role in the hydrological cycle. Historic 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.

Understanding the partitioning of carbon in different reservoirs on Earth, and the sensitivity of these reservoirs to climatic and anthropogenic factors, remains a key challenge in predicting future responses to global warming. A lot of this uncertainty stems from the inherent complexity of the carbon cycle, where physical, chemical, and biological processes interact on different temporal and spatial scales. Thus, a wide variety of tracers are needed to unravel individual processes and assess their sensitivity to climatic and anthropogenic influences.

Natural Organic matter (OM) is globally ubiquitous and a keystone interactive medium in environmental ecosystem functioning. The vast molecular diversity of natural OM may be both a symptom or a cause of its mediating role in various processes essential for life on Earth, such as nutrient retention and resupply, or climate stability. Dissolved organic matter (DOM) forms the main carbon and energy source for microbial life, still it accumulates in the oceans to one of the biggest carbon reservoirs on Earth. Pyrogenic organic matter (PyOM) is an important component of OM and is characterized by its condensed aromatic composition. It originates from natural (e.g., wildfires) and anthropogenic sources (e.g., biochar) and despite the importance of PyOM in the environment, its processing and fate remain largely unknown.

In this session, we aim to bring together the latest insights into the partitioning and size of all reservoirs of the global carbon cycle and the processes governing fluxes of carbon between these reservoirs. We invite contributions from process- to field-scale approaches and method development for a detailed understanding of isotopic and molecular composition of individual carbon reservoirs, as well as their active role within ecosystem functioning. We are interested in studies showing new field data, laboratory experiments and modeling that use geochemical tracers (e.g., 14C, biomarkers, stable and non-traditional isotopes, trace elements) combined with geomorphic and hydrological tools to unravel controls on the carbon cycle from the local to the global scale. Modern analytical tools and their combination are crucial in advancing this research field, encompassing a variety of spectroscopic and mass spectrometric techniques (AMS, NIR, MIR, NMR, XPS, py-GC-MS, HR-MS, LC-MS-MS, EEMs-PARAFAC, PTR-MS, etc.) as well as new computational approaches.

Marine, freshwater and soil systems are interconnected components in the environment, that play crucial roles in the overall functioning of the planet's ecosystems and regulating the global climate. In the face of rapidly changing environmental conditions, understanding the response of organisms to changing parameters, including the fate, transport, and impacts of contaminants, is of paramount importance for understanding ecosystem evolution and safeguarding terrestrial and aquatic ecosystems. Today, special attention must be focused on emergent contaminants, including pharmaceuticals, microplastics, and other anthropogenic compounds, which pose novel challenges in the field of environmental sciences.
The session will explore intricate biogeochemical interactions within aquatic and soil environments, elucidating the influence of microbial communities, nutrient cycles, and physical factors on faunal and ecosystem functional responses and contaminant behaviour. The session is multidisciplinary and is open to observational, experimental, and modelling studies in order to promote the dialogue. The session will comprise subsections on 1) biological and ecological experimental biogeosciences and 2) on pollution dynamics.

The session is co-sponsored by JpGU.

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.

Solicited speaker: Keri Nicoll, University of Reading, "Recent developments in dust electrification research"

Climate change and widespread biodiversity loss are urgent challenges facing humanity, whose effects threaten human wellbeing, economies and planetary stability. There is increasing evidence that these two crises are strongly interconnected and might even be mutually reinforcing. However, climate- and biodiversity change are typically investigated through siloed approaches. This limits our ability to assess the feedbacks between these two major trends and to ultimately/eventually design policy solutions that fully take into account the trade-offs and synergies between climate change mitigation, adaptation, and biodiversity conservation.

In this session, we invite scientists from all disciplines working at the interface of these fields, and in particular on the linked relationships and processes between climate (change, variability, extremes) and biodiversity (taxonomic, functional, structural). We are especially interested in studies that investigate feedbacks mechanisms between biodiversity and the climate system at different spatial and temporal scales, from experimental, observational, data-science, and/or modelling perspectives, as well as on how human activities, such as land cover conversion or nature conservation, might influence these interactions.

This session aims to (re)introduce biodiversity, an essential component of many aspects of life on Earth, as a notion that offers a wide array of multidisciplinary work from numerous fields of research, including but not limited to the geosciences and ecology. 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 ecosystems response to disturbances, affecting notions such as (ecosystem) integrity, health and resilience. Biodiversity is also intrinsically linked with the Earth’s processes, geomorphology, formation, and development. United Nation’s definition of biodiversity, or biological diversity, is: the variety of life on Earth and the natural patterns it forms. A wide range of studies on biological diversity also encompass ecological diversity, and ecosystem diversity, since the diversity of ecosystems also affects the diversity of organisms that inhabit them. Earth Science recognizes the role of biotic factors in governing geophysical processes across a wide range of spatial and temporal scales. Studies show that the control of biota might be part of a longer-term cycle, in which the dominance of biotic and abiotic processes not only switch, but depend on each other. Biota and abiotic processes may have co-evolved over both longer and shorter timescales. Scientific evidence from the geoscience community is therefore valuable in many political decisions for restoration, or rewilding, including the recent EU Nature Restoration Law. Also, research in these fields may contribute to policy on preparation for and/or prevention from natural hazards, including those that may be triggered by climate change. However, to be able to contribute to these processes, we need to be able to recognize the range of areas where our expertise is relevant and useful.

This session aims to recognize the wide range of geoscience research projects that focus on or highlight aspects of biodiversity, while welcoming those that favor inter- and/or transdisciplinary approaches. Through these presentations, we hope to demonstrate the broad spectrum of biodiversity-related areas in which the geosciences contribute and where more geoscience research is needed.

Geoscience has a long history, wound up with the history of science itself, and thus with colonialism and colonial thinking. We see the manifestation of this colonial history in practices such as “parachute science”, where international scientists, usually from higher-income countries, conduct field work or collect data and samples in another country, usually of lower income countries, and then elaborate the data and publish scientific papers without involving local scientists and/or local communities from that nation. This is an example of scientific neo-colonialism. We see this in the exploitation of local people whose lands are visited for field work and in the exclusion or partial extractive collaboration with in-country geoscientists. Part of this disparity between researchers is also reflected in the difference in experience of access to funding, ease of mobility, issues of visa and fear of speaking out against the status quo.
Building on an EGU2023 short course and Great Debate, here we propose a more informal session to provide participants with an introduction to the colonial background of geosciences, defining the terminology and outlining efforts to decolonize geosciences. Our goal is to raise awareness among the EGU members who may unintentionally be part of neo-colonial research practices and open up a space to discuss solutions. We also aim to open up the discussion for geoscientists on the receiving end of such practices to share stories, ideas and experiences to build a more inclusive, responsive community of practice.

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
- Best practices and strategies to move beyond barriers, including:
• successful mentoring programmes
• networks that work
• specific funding schemes
• examples of host institutions initiatives
- COVID-related data, discussions and initiatives

This session is co-organised with the EGU early career scientists (ECS) and the European Research Council (ERC).

This session is a merger of three sessions from Cryospheric Sciences (CR) and Biogeosciences (BG).

The original sessions were:
- Disturbance processes in permafrost regions
- Permafrost dynamics, interactions, and feedbacks: past, present, and future
- High latitude biogeochemistry: Addressing challenges in GHG, from in situ to remote sensing

This merged session collects abstracts focussing on permafrost regions and other high latitude landscapes which have experienced the highest levels of warming in the world. Permafrost shapes Arctic ecosystems and interacts with the global climate system in manifold ways. It affects the cycling of water, energy, and carbon in high latitudes and impacts climate patterns at local to global scales. Furthermore, anthropogenic activities such as the construction of roads, mining, oil and gas extraction, and agricultural expansion are increasing in these regions. Permafrost regions are highly sensitive to disturbance due to their dependence on a thermal threshold for stability and as a result they are impacted by a wide range of disturbances including wildfire, infrastructure development, the arrival of invasive species, and ongoing atmospheric warming. This can result in a myriad of geomorphological processes including thermokarst formation, mass-movement initiation, coastal erosion, and lake drainage events; all of which impact a wide range of ecosystem processes, as well as the built environment. The interplay of atmospheric warming and anthropogenic activities have likely increased the frequency and magnitude of these disturbances and altered their spatiotemporal occurrence.

This session is a forum for scientists involved in the state-of-the-art research on permafrost dynamics, disturbance processes and impacts in permafrost environments, and the mechanisms and changes in greenhouse gas cycles in these highly dynamic regions.

This session covers observations and modelling of permafrost dynamics, interactions, and feedbacks with the hydrological cycle, seasonal snow cover, biogeochemical and biogeophysical processes, and landscape processes (e.g. thermokarst, wildfires) across spatial scales.

Solar Radiation Management (SRM, also known as solar geoengineering or solar climate intervention) proposes to temporarily modify Earth's radiation budget to reduce the effects of climate change in the near term alongside decarbonization. Commonly proposed SRM methods include stratospheric aerosol injection, marine cloud brightening, cirrus cloud thinning, and surface albedo modification. The governance of proposed climate interventions must be grounded in a solid basis of natural science and engineering research which quantifies the feasibility, risks, and benefits of each proposal. Since clouds and aerosols remain large sources of uncertainty in our understanding of the drivers of climate change, accurately describing these climate forcings and their properties will help reduce uncertainties in climate projections, inform local to regional air quality control policies, and better constrain the impacts of SRM strategies.

This session focuses on advancements in the natural science of climate interventions, including climate modelling studies, ecological impacts, experimental results, and observations of natural analogues (e.g., volcanoes, ship tracks). We welcome submissions looking at the mechanisms and quantifying the impacts of cloud- or aerosol-induced changes on the biosphere, where we all live, as well as their feedback to the climate system to better constrain SRM impacts. We also encourage broader scope studies that connect the climatic and ecological impacts with the economic, social, political, or ethical implications of SRM. In particular, we strongly encourage abstracts concerning the impacts on regions that are largely vulnerable to climate change, and underrepresented communities who may be disproportionately affected.

This session is open to all contributions in biogeochemistry, ecology, and climate studies, 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 (triple oxygen, 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, multi-isotope approaches).

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

This session aims to bring together scientists from different fields applying oxygen, hydrogen, and radiogenic isotope measurements of environmentally derived compounds to unravel environmental processes and the complex interconnections existing between anthropogenic activities and the lithosphere, atmosphere, biosphere, and hydrosphere. We invite researchers working on different compounds (e.g., lipids, (hemi-) cellulose, lignin, non-structural carbohydrates, human and animal tissues, biominerals) from aquatic and terrestrial sources across all spatiotemporal scales and archives (e.g., herbarium, peat, sediments, loess, and tree rings). We also encourage researchers working with diverse techniques to present advances in methods, as well as researchers focusing on improving oxygen and hydrogen isotope-based models to discuss their approaches. In summary, the session will offer an overview of applications of oxygen and hydrogen isotopes across different ecosystems, as well as center on novel mineralogical and geochemical studies using radiogenic isotopes for improving our understanding of environmental issues related to human activities.

Recent advances in image collection, e.g. using unoccupied aerial vehicles (UAVs), and topographic measurements, e.g. using terrestrial or airborne LiDAR, are providing an unprecedented insight into landscape and process characterization in geosciences. In parallel, historical data including terrestrial, aerial, and satellite photos as well as historical digital elevation models (DEMs), can extend high-resolution time series and offer exciting potential to distinguish anthropogenic from natural causes of environmental change and to reconstruct the long-term evolution of the surface from local to regional scale.
For both historic and contemporary scenarios, the rise of techniques with ‘structure from motion’ (SfM) processing has democratized data processing and offers a new measurement paradigm to geoscientists. Photogrammetric and remote sensing data are now available on spatial scales from millimetres to kilometres and over durations of single events to lasting time series (e.g. from sub-second to decadal-duration time-lapse), allowing the evaluation of event magnitude and frequency interrelationships.
The session welcomes contributions from a broad range of geoscience disciplines such as geomorphology, cryosphere, volcanology, hydrology, bio-geosciences, and geology, addressing methodological and applied studies. Our goal is to create a diversified and interdisciplinary session to explore the potential, limitations, and challenges of topographic and orthoimage datasets for the reconstruction and interpretation of past and present 2D and 3D changes in different environments and processes. We further encourage contributions describing workflows that optimize data acquisition and processing to guarantee acceptable accuracies and to automate data application (e.g. geomorphic feature detection and tracking), and field-based experimental studies using novel multi-instrument and multi-scale methodologies. This session invites contributions on the state of the art and the latest developments in i) modern photogrammetric and topographic measurements, ii) remote sensing techniques as well as applications, iii) time-series processing and analysis, and iv) modelling and data processing tools, for instance, using machine learning approaches.

In the last decades, the use of environmental magnetism in geophysical and geological sciences has increased. Environmental magnetism provides indispensable information about sedimentary and tectonic processes, environmental redox conditions during sedimentation, diagenesis, and biological activity among others. The purpose of this session is to integrate diverse applications of environmental magnetism in the domain of geosciences

Joint topics
Topic 1. Stable and radiogenic isotopic records have been successfully used for
investigating various settings, such as palaeosols, lacustrine, loess, caves, peatlands, bogs, arid, evaporative and marine environments. We are
looking for contributions using isotopes along with mineralogical, sedimentological, biological, paleontological and chemical records in
order to unravel the past and present climate and environmental changes.
The session invites contributions presenting an applied as well as a
theoretical approach. We welcome papers related to both reconstructions
(at various timescales) as well as on fractionation factors, measurement, methods, proxy calibration, and verification.

Topic 2
Sedimentary records preserve information on their environments at the time of deposition. Such information can be accessed using a growing number of isotopic proxies. Modern sediments are crucial to calibrate such proxies and allow the sedimentary rock record to be deciphered, providing important clues to better understand the future response of the Earth system under climate change.

The sediments deposited along the transitional zone (fluvial system, continental shelf, and continental slope) to the final sink in the deep-marine basin accumulate chemical information on changes in the atmosphere, on land, and in the oceans. Specifically, changes in climate and environmental conditions, such as weathering, oxygenation, bio-productivity, and ocean circulation, can lead to variable element accumulation, isotope mixing, and isotopic fractionation.

We welcome contributions that reconstruct changes in climate and environmental conditions using sediments and sedimentary rocks from the recent to the ancient past (e.g., Last Glacial Maximum, Paleocene Eocene Thermal Maximum, Great Oxidation Event), using traditional, non-traditional, stable, and radiogenic isotope systems (e.g., Li, Mg, Cr, Fe, Sr, Mo, Nd, Pb, U). To account for the diversity of sedimentary archives, contributions on all types of archives are welcome, from carbonates to siliciclastic muds, and from biogenic to abiotic. We also encourage submissions relating to field or laboratory calibrations of these isotopic proxies.

Understanding the complex interactions between soil-plant-atmosphere compartments and human activities is critical for ensuring the sustainable management and preservation of ecosystem functions and services. Global climate change and human activities threaten the functions and services of our terrestrial ecosystems. The complexity and holistic nature of the consequences have been difficult to assess so far, as simplified experimental approaches and long-term observations have methodological constraints and often focus on a very limited set of response variables.
Larger and more realistic experimental systems such as in situ lysimeters or ecotrons can supply a wide range of high quality continuous and high-resolution data sets on ecosystem services and functions in the Earths critical zone. Individual facilities and larger networks such as TERENO-SOILCan (lysimeter) or ANAEE’s ecotron experimental infrastructures provide a unique platform for a variety of interdisciplinary research to better understand the dynamic of ecosystems.
The session will focus on ecosystem research based on lysimeters and ecotron experiments, including model application. Additionally, we want to address upscaling approaches from lysimeter to landscape scale or between several types of ecosystem experimental infrastructures (e.g., lab, field, or control environments), uncertainty assessments, representativeness of lysimeter-scale observations, and comparability of water, and greenhouse gases flux to in situ measurements. We welcome contributions that (1) assess and compare terrestrial ecosystems functioning and services, (2) focus on water and solute transport processes, as well as greenhouse gases within the soil-plant-atmosphere continuum, including processes such as non-rainfall water inputs (i.e., dew, fog, soil water vapor adsorption), (4) develop new techniques for analyzing lysimeter and ecotron observations, (5) including ecosystem or hydrological modelling approaches that use in-situ observations from lysimeters or ecotrons.

The Quaternary Period (last 2.6 million years) is characterized by frequent and abrupt climate swings that were accompanied by rapid environmental change. Studying these changes requires accurate and precise dating methods that can be effectively applied to environmental archives. A range of 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, whereas radiometric methods (radiocarbon, cosmogenic in-situ, U-Th) and luminescence dating provide independent anchors for chronologies that span over 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.

Time series are a very common type of data sets generated by observational and modeling efforts across all fields of Earth, environmental and space sciences. The characteristics of such time series may however vastly differ from one another between different applications – short vs. long, linear vs. nonlinear, univariate vs. multivariate, single- vs. multi-scale, etc., equally calling for specifically tailored methodologies as well as generalist approaches. Similarly, also the specific task of time series analysis may span a vast body of problems, including
- dimensionality/complexity reduction and identification of statistically and/or dynamically meaningful modes of (co-)variability,
- statistical and/or dynamical modeling of time series using stochastic or deterministic time series models or empirical components derived from the data,
- characterization of variability patterns in time and/or frequency domain,
- quantification various aspects of time series complexity and predictability,
- identification and quantification of different flavors of statistical interdependencies within and between time series, and
- discrimination between mere correlation and true causality among two or more time series.
According to this broad range of potential analysis goals, there exists a continuously expanding plethora of time series analysis concepts, many of which are only known to domain experts and have hardly found applications beyond narrow fields despite being potentially relevant for others, too.

Given the broad relevance and rather heterogeneous application of time series analysis methods across disciplines, this session shall serve as a knowledge incubator fostering cross-disciplinary knowledge transfer and corresponding cross-fertilization among the different disciplines gathering at the EGU General Assembly. We equally solicit contributions on methodological developments and theoretical studies of different methodologies as well as applications and case studies highlighting the potentials as well as limitations of different techniques across all fields of Earth, environmental and space sciences and beyond.

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.

In recent periods, carbon sequestration by forests has attracted much interest as a mitigation approach and as a valuable nature-based option to address climate change mitigation challenges, to protect forest ecosystems, and to support socioeconomic and environmental services. The technological advancements and the constant focus of the scientific community have boosted the implementation of forest management practices that support the multiple functions of various forest types, soil and biodiversity conservation, the prevention of major disturbances (large droughts, wildfires, impacts of hurricanes, heavy snowfalls and floods, etc.) and the increase of forest carbon stock capacity in the short-, medium-, and even to long-term. This session aims to contribute to a better understanding and to shed light on the forests’ capacities to mitigate climate change, bringing together the latest advances from multi- and interdisciplinary studies (e.g. advanced ICTs, modeling, climatology, hydrology, soil science, or ecology), while considering the broad range of other forest values and ecosystem services in the context of bioeconomy and rural development. We invite forest scientists and experts working in other related disciplines, such as climatology, biophysical, and socio-economic modeling, to share their findings within this session, and improve the science-based knowledge on the environmental benefits, the social acceptability and the economic value of forest-based mitigation actions.

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. Observed, and likely future, changes in vegetation structure and functioning are the result of interactions of these processes 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 large scales and over the long time periods required to evaluate trends.

This limited observation base gives rise to high uncertainty as to whether the terrestrial vegetation will continue to act as a carbon sink 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 and carbon stocks and fluxes at local, regional or global scales and/or at long time scales.

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.

Natural disturbances are one of the most important factors that shape the structure and composition of forests. Climate and land use changes are deeply altering forest disturbance regimes, potentially impacting ecosystems balance and structure, increasing hazard and risk for human health and threatening the provision of many ecosystem services (ES). Given the multitude of functions and services required from forests, it is crucial to understand the impact of recent natural disturbances on forests, especially with the alterations introduced by different global change drivers. Such modifications in the environmental conditions trigger new interactions among biotic, abiotic, and anthropogenic disturbances, which in turn can lead to increased severity and significant alterations of post-disturbance environment. Compound disturbances and cascading processes are increasing in frequency and raising their importance as limiting factors in the provision of forest ES. Therefore, higher attention is needed to analyze these phenomena. Despite the increasing awareness of the fundamental ecological role of natural disturbances, scientifically sound practices for increasing the resistance and resilience of forests and promoting natural regeneration are still lacking. A focus on post-disturbance management is needed to choose the more appropriate intervention, in terms of intensity and timing, that promotes effective forest recovery. Moreover, first place must be given to forest restoration and regeneration strategies, to reduce the loss of ES provisioning and re-establish the targeted forest function. This complex scenario requires solid scientific input, calling for multidisciplinary and multiscale analytical approaches. Remote sensing, in-field surveys, statistical and mechanistic models are some of the tools required for the detection, quantification, and management of forest disturbances and their effects on forest functions, ecosystem dynamics, and ecosystem services provisioning. In this session, we invite contributions from all the fields to promote knowledge and new methodologies to assess forest disturbances, from detection and mapping to the investigation of ecological processes and post-disturbance management, also through the use of numerical models. Particular attention will be paid to multiscale and multidisciplinary analysis dealing with the spatiotemporal characteristics of the processes and their interaction with climate, land use, and ES provisioning.

This is the new edition of 2023's 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 climate change from a global range of pedogenic and environmental settings.
Climate change is affecting the dynamic feedbacks between plant, 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-soil system, and what are the resulting effects on soil biogeochemistry? Given the positive and negative feedbacks with the climate system, dynamics of soil organic matter across terrestrial ecosystems are a key focus of this session.
We invite contributions from manipulative field experiments, observations in natural-climate gradients, and modelling studies that explore the climate 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 year's invited speakers are: Dr. Kaizad Patel (Pacific Northwest National Lab) and Dr. Melanie Brunn (Koblenz University)

The present context of accelerated changes in both climate and land use imposes an unprecedent pressure on global ecosystems. The influences of landform and land use on soil-plant relationships and related subsoil processes are crucial for ecosystem service maintenance and restoration. This understanding is necessary to develop management practices to improve climate change adaptation, food security as well as providing habitats for soil biodiversity. In particular we focus on the role of different ecosystem components such as subsoil and roots that are often neglected.
The purpose of this session is to understand soil-plant interaction across landforms, including distribution of vegetation and coevolving soils and landforms, as well as related subsoil processes and root growths. In particular, theoretical, modelling, and empirical studies are welcome on subsoil functions, investigating root traits and rhizosphere processes on ecosystem services, degradation and biogeochemical cycling in different ecosystems and land uses. We also include studies on the implications of spatial patterns of soil-plant systems for the resilience and stability of ecosystems The session will have a particular interest on global changes effects on those processes and dynamics.

Soil fauna perform many ecological functions that control ecosystem nutrient dynamics, regulate primary productivity, develop and maintain soil structure, and contribute to the quality of the atmosphere and water supply. Over recent decades, research has revealed interesting facts about soil fauna such as their contribution to ecosystem stability, pesticide remediation, multitrophic interactions that link above and belowground energy fluxes, etc. The proposed session encourages submissions from all aspects of research dealing with the effects of soil fauna on biogeochemical cycles, such as (1) the regulation of soil organic matter decomposition, (2) nutrient cycling and soil fertility, (3) soil carbon storage, (4) greenhouse gas emissions, (5) soil hydrology and nutrient leaching, (6) ecosystem energy fluxes, (etc.). The organizers are hoping to attract participants with diverse backgrounds, with the intended purpose of fostering scientific interactions and collaborations among individuals and established research networks. We welcome submissions from students, early-career and well-established researchers.

Peatland restoration for conservation purposes can solve many problems related to drained peatlands and has been implemented for decades now. However, innovative management measures that sustain economically viable biomass production while reducing negative environmental impacts including greenhouse gas (GHG) emissions, fire risk and supporting ecosystem services of organic soils are only currently studied. Those 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. We invite studies addressing all types of peatland management, i.e. agriculture, forestry and “classical” restoration, their integration into GHG inventories and their impacts on ecosystem services and biodiversity regionally and nationally as well as their integration into GHG inventories. Work on all spatial scales from laboratory to national level addressing biogeochemical and biological aspects and 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.

Northern peatlands contain large reservoirs of carbon and are targets for both protection and restoration, serving as critical buffers against climate change. We seek to understand responses of northern peatlands to natural and anthropogenic stressors and disturbances, and how these stressors could potentially shift these systems between functioning as sinks and sources of greenhouse gasses. Changes in the overall ecosystem structure and function are also of interest. We welcome submissions involving experimental manipulations, anthropogenic modifications, gradient studies, and other short- and long-term climate or environmental changes in both natural and restored peatland ecosystems. 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. We particularly welcome modelling studies that use theoretical approaches and observational data to understand current functions and predict future peatland carbon trajectories.

The importance of peatlands and their crucial role in the global carbon cycle has come to the fore in the last decade. They provide many of Natures Contributions to People. However, the extent and status of peatlands at national, regional and global scales is not clear. This is due to numerous issues including land use change and conversion, remote locations, lack of data, and differing definitions. This has led to estimates of the global extent of peatlands between 423 to 500 million hectares, and therefore a critical uncertainty in the C stocks stored in peatlands. While there have been advancements in the mapping of peatlands, there needs to be much more focus on identifying these high organic carbon soils. Progress in mapping peatland land use, peat thickness and drainage conditions will also help to fill this knowledge gap. Our knowledge of tropical peatlands remains particularly uncertain due to inadequate data. In a natural condition, tropical peatlands are long-term C stores and support livelihoods, but anthropogenic disturbances (logging, drainage, degradation, agricultural conversion, fire, resource exploration) are increasing in extent. These transformations result in high C loss, reduced C storage, increased greenhouse gas (GHG) emissions, loss of hydrological integrity, peat subsidence and loss, increased risk of fire. For agricultural peatlands, changes in nutrient storage and cycling necessitate fertilizer use, with enhanced emissions of N2O. Under a warming climate, these impacts are likely to intensify and reduce not only the extent of peatlands, but also the benefits to rural communities.

This session addresses all aspects of peatland mapping and tropical peatland science, including top-down and bottom-up peatland mapping and monitoring, the application of new remote sensing techniques and integration of old maps into peatland inventories. For tropical peatlands, we consider not only mapping and monitoring needs, but also the impact of climate on past, present and future peatland formation, accumulation and C dynamics; GHG and nutrient flux dynamics; and management strategies for GHG emissions mitigation and the maintenance or restoration of C sequestration.

Grasslands cover about 40% of the Earth’s ice-free land surface, and their soils play a key role in climate regulation by storing about 20% of global carbon (C) stocks. These ecosystems are also characterized by its potential to sequester C as well as by emitting greenhouse gases (GHGs) such as CO2, N2O and CH4. In the last decades, intensified grassland management has resulted in a grassland deterioration and subsequent soil C loss and enhanced GHG emissions. Reverting this trend offers huge opportunities for climate change mitigation with the potential to sequester up to 150 Tg of soil C per year (CO2 eq) through adequate management practices such as improved grazing management or the introduction of silvopastoral systems (SPS). In addition, the promotion of legumes or organic fertilizers can reduce the use of synthetic N fertilizers limiting the negative impacts of fertilization. Making this C sequestration and GHG mitigation potential become reality will require both, joint action and thorough understanding of the mechanisms underlying C sequestration and GHG mitigation across different environmental conditions and grassland systems. Although several restoration strategies and improved management practices have been tested, there is still a lack of evidence of the mechanisms driving the C sequestration potential and GHGs mitigation by these management strategies at across the globe.
This session will focus on studies aiming to evaluate the impact of different grassland restoration- and management practices on soil nutrient C and N cycling emphasizing on soil C sequestration and GHG emission and mitigation. These grassland management practices encompass different grazing management strategies, grazing exclusion, fertilization optimization, organic farming, promotion of legumes and silvopastoral systems, use of improved forages or soil liming. Field and modelling studies are encouraged, although mesocosms studies testing hypothesis related to C and N cycling of grassland soils are also welcome.

Climate change is one of the most critical challenges facing humanity. Microorganisms play a pivotal role in both production and consumption of the major greenhouse gases (GHG): carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). To mitigate the emissions of these GHGs and the escalating impact of global warming, a better understanding of the microbes, their processes and environmental drivers and their effect on the GHG balance is needed. Depending on the environmental conditions, terrestrial microbes can change landscapes to significant sources or sinks of GHG.
This session aims to bring together scientists in microbiology, biogeochemistry, and soil and GHG sciences to advance our understanding of the carbon and nitrogen cycling in the soil-plant-atmosphere continuum affecting GHG emissions.
One important focus of this session is on microbial processes such as decomposition, respiration, methanogenesis, methanotrophy, nitrification, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) are directly responsible for the microbial GHG fluxes, and their rates differ in organic and mineral soils and in temperate and tropical ecosystems. These processes and the microbes can be studied in lab and field experiments using different methods, for example, quantifying functional marker genes, omics-based approaches (including sequencing and metagenomics), culturing, isotopic analyses, and GHG measurements and modelling.
Another important focus is on the environmental drivers and key factors, including physical soil structure (porosity, texture, structure), soil chemical properties (pH, Redox) and soil conditions (temperature, water content). Understanding the interplay between these factors and the main transport mechanisms in the liquid and gas phases is also essential to understand microbial interactions and their effect on GHG turnover in soils, as well as non-microbial geogenic or technical GHG fluxes.
In this session, we encourage submissions containing small to large spatial and temporal scales, new methodologies, mechanistic studies in model organisms, and studies in different terrestrial ecosystems locally and globally, aiming to tackle the aforementioned challenges by studying the processes and microbial communities underpinning net GHG fluxes and other emissions such as volatile organic compounds (VOC).

The majority of world forest ecosystems are subject to a number of natural and anthropogenic disturbances (e.g. drought and adverse weather events, wildfires, pests, diseases). These can severely affect their health and vitality by causing tree mortality or by reducing their ability to provide the full range of goods and services. 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 forest assessment, spanning a range of scales and conditions. In particular, we welcome submissions on the following subjects:

• Mapping and predicting forest mortality and die-back phenomena under global warming.
• Evaluation of the effects of natural and anthropogenic disturbances on forest health and growth.
•Estimation of genetic factors and molecular mechanisms that regulate tree growth and cambial development.
• Vulnerability of old-growth forests and mountainous forest ecosystems to climate change.
• Multidisciplinary approaches towards monitoring and modelling tree vulnerability at the local, regional and global scale.
• Estimation of resistance, resilience and recovery of forests in drought-prone areas.
• Interdisciplinary forestry research covering not only ecological but also economic and social aspects.
• Effects of forest adaptive management on forest health and vulnerability.
• Methods and tools for decision support and adaptation support in the forestry sector.
• Modelling growth at different scales: wood, tree, forest.

The microclimate within terrestrial ecosystems is highly heterogeneous as it responds to a multitude of local and landscape-scale factors such as foliage density, micro-topography, distance to a forest edge or a water body. This diversity of microclimates, and the potential buffering of climate extremes in the landscape, are key to understand terrestrial biodiversity and ecosystem functioning (notably carbon, water and nutrient cycling), but also ecosystem resilience and feedback onto regional climate. Despite our good understanding of the biophysical processes driving microclimate, it is still very challenging to describe and predict how microclimate varies across the landscape, and anticipate the impact of changes in climate, land use or ecosystem management.
In this session, we welcome observational, experimental and modelling studies on terrestrial microclimate, its role on biodiversity, biogeochemical cycles, ecosystem resilience and its response to climate and land use change.

Treeline ecotones are transition zones between closed forest and climatically tree-less areas. Due to their climate sensitivity they are considered sentinels of global-change effects on terrestrial ecosystems. Vegetation patterns in treeline ecotones are constrained by multiple factors acting at different spatial and temporal scales. Climatic treeline positions are strongly influenced by global- and regional-scale climatic patterns, but other factors such as soil, meso-topography, and natural and anthropogenic disturbances dominate patterns at the landscape scale. Moreover, species competition/facilitation and micro-topographic heterogeneity are key factors for vegetation dynamics at finer scales. A current trend in vegetation dynamics both at latitudinal and altitudinal treelines is the accelerated encroachment of trees and shrubs, caused by interactions between climate and land-use changes. This encroachment can have far-reaching consequences for the biodiversity and functioning of mountain and subarctic ecosystems. Spatial vegetation patterns likely hold important information about the factors and processes (e.g. seed dispersal, safe-site characteristics, biotic interactions) that control this encroachment, yet few of treeline research deals with the spatial component of patterns and processes. For this reason, it is crucial to improve our understanding of spatial processes and the spatial signals of global change impacts in treeline ecotones and there is a need for a multiscale and multidisciplinary approach, to plan better adaptation strategies and monitor biodiversity trends in such sensitive ecosystems and to better link treeline metrics to ecological questions. Specifically, remote sensing can be combined with field data and modeling to capture the heterogeneity and variability of ecological conditions in treeline ecotones and couple observed spatial patterns to ecological processes. In this session, we invite contributions from all fields of research related to either the detection and description of treeline spatial and temporal patterns or the processes that may be relevant for these patterns.

The need to predict ecosystem responses to anthropogenic change, including but not limited to changes in climate and increased atmospheric CO2 concentrations, and the interlinked carbon and water cycles 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 across scales with vegetation diversity and ecosystem function is vital to enable predictive capacity in our forecast tools.
This session aims to bring together scientists interested in advancing our fundamental understanding of vegetation and whole-ecosystem processes, with a special focus on the complex relationship between the carbon cycle and ecohydrology in natural and managed ecosystems under a changing climate.
We are interested in contributions focused on advancing process- and hypothesis-driven understanding of plant ecophysiology, biodiversity and ecosystem function, particularly of interlinks between carbon and water cycles. We welcome studies on a range of scales from greenhouse and mesocosm experiments to large field manipulative experiments, remote sensing studies and process-based modelling, including basic research and management aspects. We encourage contributions of novel ideas and hypotheses in particular those from early stage researchers and hope the session can create an environment where such ideas can be discussed freely.

Carbon dynamics are an essential feature of ecosystem functioning. They are highly sensitive to environmental changes and play an important role in ecosystem – climate feedbacks. Carbon allocation is a key process underlying carbon dynamics: it is coupled with plant growth, fuels metabolism and affects carbon sequestration in standing biomass and soil organic matter. This session will explore carbon dynamics and the particular role of carbon allocation across temporal and spatial scales. It consists of three parts:

Part 1 will address questions at the core of carbon allocation, including 1) what drives carbon allocation in plants and ecosystems?; 2) what is the fate of newly assimilated carbon?; 3) what determines the allocation of nonstructural carbon to growth, metabolism, exudation and storage?, 4) how does carbon allocation affect nutrient and water relations in plants and ecosystems?; and 5) how do allocation patterns change under changing environmental conditions and what are the consequences for biogeochemical cycles?

Part 2 will address the broader relationships between photosynthesis and respiration, carbon allocation to different tissues, woody biomass production, and long-term storage in ecosystems. It will focus on the variability of carbon allocation to biomass formation across seasons and years, and how disturbances and decomposition processes influence carbon persistence in ecosystems. It will address unresolved issues in carbon cycling in woody ecosystems and explore the connections between climate, carbon sequestration, allocation, and storage in woody ecosystems such as vineyards, orchards, tree plantations, and forests.

Part 3 will focus on carbon dynamics in the context of post-disturbance forest dynamics, including a.o. carbon losses due to post-disturbance mortality and carbon gains due to forest recovery on abandoned, deforested or degraded forest landscapes. By delving deeper into the spatial and temporal dynamics of forest regrowth and recovery, we will explore the potential for carbon removal with respect to unresolved scientific questions and policy implications, e.g. in the context of the jurisdictional systems of REDD+ (Reduction of Emissions from Deforestation and Forest Degradation) and of regional to global carbon cycle assessments.

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 and 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.

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 uptaking and transporting 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, forest ecosystem type, environmental parameters and seasonal dynamics. Soil - vegetation - 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 measured with chamber systems, or integrated ecosystem approaches (flux tower with Eddy covariance, satellite or modelling) would be very appreciated.

A robust representation of the biosphere-atmosphere interactions requires fundamental understanding of carbon, energy and water fluxes, particularly in a changing climate. Multiple processes determine how mass and energy exchanges scale from the leaf, to the whole plant, to the ecosystem, and eventually to the globe. Earth system models continue to evolve and incorporate increasingly complex processes across these scales, however, with that also the spread across models is increasing without reducing the uncertainties. In addition, climate is changing at an unprecedented rate and the frequency and intensity of extreme conditions is increasing globally, challenging our ability to robustly formulate the mechanistic underpinnings of biogeochemical processes across scales. The increasing amount of data at multiple scales, ranging from leaf-level measurements (e.g., gas exchange), tree-level measurements (e.g., sap flow and tree growth, dendroecology), ecosystem-level measurements (e.g., eddy covariance towers, lidar, UAVs, aircrafts) to Earth observation from space (e.g., solar-induced fluorescence, land surface temperature, vegetation optical depth), are opening new opportunities to tackle these challenges.
This session invites studies that improve our overall understanding of biosphere-atmosphere interactions by combining observations at different temporal and spatial scales as well as their integration into modeling strategies. We also invite studies that explore the effect of climate extremes (e.g., drought, heatwaves, excess rainfall, winter warming) on carbon and water fluxes across different scales (from the tree to the ecosystem to the continental scales) and biomes (forests, grasslands, wetlands, …). In addition to empirical multi-scale observations, we invite research that explore data-driven diagnostics and constraints for model evaluation, data-driven parameterizations in mechanistic models and other developments of data-driven/hybrid modeling strategies (i.e., seamless fusion of data-driven approaches and mechanistic models) for an integrated understanding of carbon and water fluxes across scales.

Managed agricultural ecosystems (grassland and cropland) are an important source and/or sink for greenhouse gases (GHG) as well as for reactive trace gases. Representative measurements and modelling under typical conditions as well as for potential mitigation options are necessary as a basis for recommendations to policy makers and farmers.
Due to the simultaneous influence of various environmental drivers and management activities (e.g. fertilizer application, harvest, grazing) the flux patterns are often complex and difficult to attribute to individual drivers. Moreover, management related mitigation options may often result in trade-offs between different GHG or between emission of GHG and reactive gases like NH3, NOx, or VOCs. To investigate these interactions, the session addresses experimentalists and modelers working on carbon and nitrogen cycling processes and related fluxes on plot, field, landscape, and regional scale. It is open to a wide range of studies including the development and application of new devices, methods, and model approaches as well as field observations and process studies. Particularly welcome are studies on multiple gases and on the full carbon, nitrogen or GHG budgets. We also encourage contributions about the applicability and overall potential of mitigation options.

Rising temperatures, vapor pressure deficit, and the exacerbation of soil droughts severely endanger functions and services provided by terrestrial ecosystems. Ecosystem water status directly impacts key physiological processes such as carbon uptake, transpiration, growth, and mortality. Even when soil moisture is not low, increased atmospheric dryness can accelerate drought development as evapotranspiration increases albeit a decrease in stomatal conductance, which reduces terrestrial gross and net primary productivity, and elevates risks of plant mortality. However, due to the complexity of these interactions and the scarcity of continuous timeseries, the magnitude and timing of heat and water stress impacts on ecosystem function have proven difficult to quantify. As climate change accelerates the constraints of heat, soil, and atmospheric droughts on ecosystems, we must harmonize our efforts to characterize plant and ecosystem functions and develop frameworks for monitoring and prediction.

In this PSInet sponsored session, we broadly explore high temperature, evaporative demand and soil moisture’s role in terrestrial ecosystem carbon, water, and energy relations across various spatial and temporal scales. We encourage submission dealing with novel approaches for measuring and modeling plant and soil water status, their interaction with physiological traits, 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 modelling approaches, and dealing with diverse disciplines such as plant physiology, community ecology, ecosystem ecology, land management, and biogeochemistry.

Gross photosynthetic CO2 uptake is the single largest component of the global carbon cycle and a crucial variable for monitoring and understanding global biogeochemical cycles and fundamental ecosystem services. Nowadays routine measurements of the net biosphere-atmosphere CO2 exchange are conducted at the ecosystem scale in a large variety of ecosystem types across the globe. Gross photosynthetic and ecosystem respiratory fluxes are then typically inferred from the net CO2 exchange and used for benchmarking of terrestrial biosphere models or as backbones for upscaling exercises. Uncertainty in the responses of photosynthesis and respiration to the climate and environmental conditions is a major source of uncertainty in predictions of ecosystem-atmosphere feedbacks under climate change. On the other hand, transpiration estimates both at ecosystem to global scales are highly uncertain with estimates ranging from 20 to 90 % of total evapotranspiration. The most important bottleneck to narrow down the uncertainty in transpiration estimates is the fact that direct measurements of transpiration are uncertain and techniques like eddy covariance measure only the total evapotranspiration.
During the last decade, technological developments in field spectroscopy, including remote and proximal sensing of sun-induced fluorescence, as well as in isotope flux measurements and quantum cascade lasers have enabled alternative approaches for constraining ecosystem-scale photosynthesis, respiration and transpiration. On the other hand, a variety of approaches have been developed to directly assess the gross fluxes of CO2 and transpiration by using both process based and empirical models, and machine learning techniques.
In this session, we aim at reviewing recent progress made with novel approaches of constraining ecosystem gross photosynthesis, respiration and transpiration and at discussing their weaknesses and future steps required to reduce the uncertainty of present-day estimates. To this end, we are seeking contributions that use emerging constrains to improve the ability to quantify respiration and photosynthesis processes, transpiration and water use efficiency, at scales from leaf to ecosystem and global. Particularly welcome are studies reporting advancements and new developments in CO2 and evapotranspiration flux partitioning from eddy covariance data, the use of carbonyl sulfide, stable isotopes approaches and sun-induced fluorescence.

The terrestrial water and carbon cycles are tightly coupled through gas diffusion in plant stomata (physiological effect) and the greenhouse gas (GHG) forcing of CO2 on climate (GHG effect). Those two effects (physiological and GHG) simultaneously affect the terrestrial energy, water, and carbon cycles. Facing a continuous increase in atmospheric CO2 concentrations, the interaction between the global carbon and water cycles has emerged as a critical topic in hydrological science, and it has profound implications for water resources. This session invites submissions addressing (1) coupled modeling of carbon and water fluxes, including crop yields, and/or biomass and mineral carbon sequestration, (2) observation-based assessments of interactions between the terrestrial water and carbon cycles across different scales, including their sensitivity to climatic extremes such as droughts and heat waves, (3) impact of climate change on the interactions between water and carbon cycles, (4) theory linking transpiration and photosynthesis, such as optimality hypotheses, and (5) sustainable land management practices preserving/enhancing water resources and carbon stocks. Submissions introducing promising, new observation techniques, modeling approaches, or novel theories are particularly welcomed.

The Critical Zone (CZ) – the permeable near-surface layer of the Earth where the lithosphere, hydrosphere, atmosphere, and biosphere interact – is the place where cycles of carbon, nutrients, water and other biogeochemical processes intersect with ecosystems and society. Investigating the form and functioning of the CZ requires that insights from geology, hydrology, ecology, geochemistry, atmospheric science and other disciplines are integrated in a transdisciplinary manner. One successful approach to CZ research has been the development of intensively instrumented study areas, known as CZ observatories. Networks of observatories and interlinked thematically-focused projects have evolved to capitalize on advances possible through multifaceted collaborations across larger spatial scales. Processes that shape the critical zone also span wide ranges of temporal scales, from vegetation on seasonal timescales, to soil development and landscape evolution over thousands to millions of years. Because all of these processes together shape the critical zone and affect how it functions, bridging gaps between short term processes and longer-term environmental change is essential for understanding landscapes and maintaining their ability to sustain life.

This session will highlight the cutting edge of CZ science across spatial and administrative scales, from project, to observatory, to network levels. Submissions may also explore coupling across temporal scales, integrating relatively rapid processes with the longer-term evolution of the critical zone. Submissions are solicited that focus on integration of observations and modeling; hydrologic dynamics; geoecological interactions; biogeomorphology, mineral weathering and nutrient cycling; the rhizosphere; the societal relevance of CZ science; and other examples of how CZ research is evolving with new knowledge to face the challenges of our changing world. Contributions from early-career scientists are particularly encouraged.

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 session is addressed to experimentalists and modelers working on air-land interactions from local to regional scales including urban and natural terrestrial ecosystems. The programme is open to a wide range of new studies in micrometeorology and related atmospheric and remote sensing disciplines. The topics include the development of new devices, measurement techniques, experimental design, data analysis methods, as well as novel findings on surface layer theory and parametrization, including local and non-local processes. The theoretical parts encompass soil-vegetation-atmosphere transport, internal boundary-layer theories and flux footprint analyses. Of special interest are synergistic studies employing experimental data, parametrizations and models. This includes energy and trace gas fluxes (inert and reactive) as well as water, carbon dioxide and other GHG fluxes, and processes related to fog, dew, and water vapour adsorption. Specific focus is given to 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, stable stratification and night time fluxes, dynamic interactions with atmosphere, plants (in canopy and above canopy) and soils, and biophysical effects.

Land use and land cover change (LULCC), including land management, has the capacity to alter the climate by disrupting land-atmosphere fluxes of carbon, water and energy. Thus, there is a particular interest in understanding the role of LULCC as it relates to climate mitigation (e.g., CO2 removal from the atmosphere) and adaptation (e.g., shifts in land use or management) strategies. Recent work has highlighted tradeoffs between the biogeophysical (e.g. changes in surface properties such as albedo, roughness and evapotranspiration) and biogeochemical effects (e.g., carbon and nitrogen emissions) of land management and change on weather and climate. However, characterizing the relationship between these effects with respect to their extents and the effective net outcome remains challenging due to the overall complexity of the Earth system. Recent advances exploiting Earth system modelling and Earth observation tools are opening new possibilities to better describe LULCC and its effects at multiple temporal and spatial scales. An increasing focus on land-based mitigation and adaptation strategies to meet more stringent emissions targets has expanded the range of land management practices considered specifically for their potential to alter biogeophysical and biogeochemical cycles. This session invites studies that improve our understanding of LULCC-related climate and weather perturbations from biogeophysical and biogeochemical standpoints, either separately or focused on the intersection between these two factors. This includes studies focusing on LULCC that can inform land-based climate mitigation and adaptation policies. Observation-based and model-based analyses at local to global scales are welcome, including those that incorporate both modeling and observational approaches.

Soil microbial communities exert control over carbon and nutrient cycling and they are playing a central role in shaping the impacts of anthropogenic greenhouse gas emissions on the global climate. These communities are also susceptible to both gradual shifts in climate and abrupt weather events, which can trigger substantial feedback loops in biogeochemical cycling. Therefore, understanding the impacts of climate and environmental stressors on soil microbial communities and their functioning is essential for forecasting the future trajectory of ecosystem-level biogeochemical cycling of carbon and nutrients.

This session aims to shed light on the effects of diverse climate scenarios on soil microbial communities, biogeochemical cycling, and their feedback to climate change. Our focus spans over diverse aspects of climate change, ranging from gradual shifts such as increasing temperature or atmospheric CO2 levels, to the influence of extreme weather events like drying-rewetting cycles, heatwaves, or floods. We invite studies that investigate the resilience and associated recovery dynamics of soil biota to environmental disturbances, as well as investigations on their resistance or adaptation mechanisms. We also welcome research on the interactions between soil microorganisms, plants and fauna. With this session, we aim to foster connections among researchers from diverse disciplines, establishing a discussion platform to review the current state of the-art, identify knowledge gaps, exchange ideas, and address emerging challenges within the field.

Soil systems harbor a highly diverse spatial organization of its functions shaping biogeochemical cycles. From microbial microenvironments via physical soil structure and various chemical differentiation by pedogenetic or anthropogenic processes up to the landscape scale. In this session, we invite diverse studies that open our views on the spatial heterogeneity in soils from biological, physical, and chemical perspectives related to organic matter dynamics and other biogeochemical cycles.

We look forward to discuss insights across different scales and structures. Zooming in provides the opportunity to observe microbial habitats and processes, probe highly active spheres around roots or detritus, and follow the interactions of organic matter with mineral phases. Aggregated structures and a network of soil pores provides a dynamic scaffolding, which can protect soil components and influence local water retention and elemental distribution. Pedogenetic soil processes drive the differentiation at pedon scale and can result from a combination of small-scale processes determining soil ecosystem fluxes up to the landscape scale.

This session is of interest to soil scientists with complementary biogeochemical and physical backgrounds working at different scales. We especially encourage contributions that address the importance of spatial heterogeneity and architecture for ecosystem-relevant soil functions, such as the occlusion of organic residues, microbial colonization, provision of water and nutrients, the fate of soil contaminants, and many more. Different experimental imaging approaches, analytical techniques and data-driven modelling works are invited. We aim to discuss recent achievements, current obstacles, and future research directions to strengthen our conceptual understanding of the linkage of spatial heterogeneity with soil functions, biogeochemical cycling, and organic matter dynamics across scales.

Soil is the largest carbon (C) reservoir in terrestrial ecosystems and soil organic carbon (SOC) is the basis for soil’s biodiversity, health and fertility. The sustainable management of ecosystems to enhance both, soil and subsoil organic C storage is one strategy to mitigate climate change and to provide soil-related ecosystem services. However, long-term C sequestration is critically dependent on short-term and long management, including the input of other nutrients, soil intrinsic characteristics and land use.
Investing in productive, highly resilient and sustainable ecosystems, based on appropriate land and soil management requires the knowledge base on drivers and processes controlling soil C storage and cycling.
Thus, this session will provide knowledge about the key mechanisms and proxies controlling physico-chemical and microbial dynamics of soil Carbon-Nitrogen-Phosphorus (CNP) (both organic and inorganic) to foster higher soil C sequestration and enhance the sustainability of agricultural and (semi-)natural systems.
Studies, opinions and other contributions in this session will aim to a wide range of topics related to SOC and soil inorganic carbon (SIC) and the relationship between them. These topics may also include soil fertility, provision of ecosystem services, and their changes. Ultimately, approaches informing management strategies in agricultural and natural systems will be summarised to help the translation of scientific knowledge into policy frameworks.
Types of contribution appreciated include, but are not limited to, definitive and intermediate results; project outcomes; proposal of methods or sampling and modelling strategies, and the assessment of their effectiveness; projection of previous results at the light of climate change and climatic extremes; literature surveys, reviews, meta-analysis; and opinions. These works will be evaluated at the light of the organization of a special issue in an impacted journal.

Microbial metabolism is the engine of key soil functions (e.g. nutrient cycling, carbon transformation, clean water provision) with this engine’s performance determined by energy and matter fluxes that follow the laws of thermodynamics. For growth and anabolism, microbes require not only C and energy, delivered chiefly by the oxidation of soil organic matter (SOM), but various nutrients (e.g., N and P) in stoichiometric relationships. Soil microorganisms therefore couple energy and element flows via complex mechanisms whereby organic matter may be mineralized, invested in cellular reproduction or transformed into a diversity of storage compounds and microbial products. Microbial death processes close the loop to return biomass to non-living SOM as necromass, changing its original quality. This coupled, dynamic system can be investigated from diverse perspectives, such as carbon or energy use efficiency, microbial ecophysiology, bioenergetics, and ecological stoichiometry. Knowledge of the drivers and regulators of microbial energy and matter fluxes is needed to understand the balance between SOM mineralization and accumulation as well as associated C, energy and nutrient budgets. This session integrates experimental, conceptual and modelling insights to elucidate the energy and matter flows governed by soil microbial metabolism and bioenergetics, their dependency on environmental conditions, and the implications for soil functioning.

The session seeks to understand how, when and where soil microorganisms transform OM and energy through their metabolism, growth and death and how bioenergetics regulates these processes. Topics of interest include characterization of microbial turnover and SOM using advanced methods (e.g., isotopic labelling, calorimetry), alongside approaches revealing the effect of microbial community composition and activity on soil functions, and functional responses to environmental change. The session will stimulate innovative and interdisciplinary discussions to advance the field of soil biology at scales from the mechanistic understanding of biogeochemical processes to global change.

Blue carbon ecosystems are coastal vegetated environments that are among the most carbon-dense ecosystems on Earth. They include salt marshes, mangroves, seagrasses and, more recently, macro-algae. These ecosystems provide nature-based solutions essential to mitigate residual anthropogenic carbon emissions, while also delivering co-benefits such as biodiversity support or coastal protection. Yet, coastal vegetated ecosystems are increasingly under pressure from climate change and local anthropogenic activities that are already affecting their carbon dynamics. There is a pressing need to better address those global changes impacts by better understanding the carbon cycle in these ecosystems. In particular, this requires to better understand the feedback loops between soil carbon and plants, the intricate exchanges of carbon between the atmosphere, soil, and water, and the interplay between human activities and carbon dynamics in vegetated coastal ecosystems.
The purpose of this session is to foster a convergence of scientists from multiple disciplines, including biogeochemists, ecologists, geographers, geologists, social scientists, biologists, and also environmental managers. The session aims to highlight pioneering studies that i) advance our comprehension of all processes related to carbon in salt marshes, mangroves, seagrasses and macro-algae under current and future environmental conditions; and ii) spotlight successful management, conservation, and restoration practices to keep or enhance the carbon sequestration service with delivery of co-benefits. This session will contribute to the United Nations Decade for Ocean Sciences, with co-convenorship by the Decade Programme for Blue Carbon in the Global Ocean.

Coastal and marine sedimentary systems are crucial components of the global carbon cycle and potentially play an important role in global climate regulation over varying timescales. Coastal vegetated habitats (classical Blue Carbon) such as seagrass, saltmarsh and mangroves, alongside marine sedimentary environments are estimated to trap and store globally significant quantities of carbon and potentially provide an important climate regulation service. Though these environments are clearly valuable both for carbon storage and climate change mitigation, these ecosystems are under growing natural and anthropogenic pressure with seagrass and saltmarsh extent decreasing annually and marine sediments being regularly disturbed (e.g., trawling, dredging).

These anthropogenic activities can modify sedimentary alkalinity generation and the burial efficiency of carbon, either through direct disturbance of the seafloor or indirectly by changing carbon supply, physical fields and/or ecosystem functions. These activities, their connection to the global carbon cycle, and implications for marine spatial management strategies are clearly significant. However, the magnitude of C release from such disturbance and what effect this has on the climate remains poorly quantified, hindering the development of policy and management.

To tackle the science questions and fill the policy needs in the field of Blue Carbon, we seek to bring together expertise from across the geosciences (e.g., ecology, biogeochemistry, sedimentology, minerology, spatial modelling). In this multidisciplinary session, we invite presentations from across these disciplines, scales (local, national, and/or global) and across study types (observational, experimental, modelling, and/or theoretical) to discuss recent advances in coastal and marine sedimentary carbon research.

Our ability to understand biogeochemical cycles of carbon, nitrogen and phosphorus and other elements in aquatic ecosystems has evolved enormously thanks to advancements in in situ sensor and 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 freshwater aquatic environments, streams, rivers, lakes, wetlands and estuaries, controlling the fate of organic matter, nutrients, sediments and other chemical substances. In particular, our session focuses on improving the characterisation of the origins, delivery pathways, transformations and environmental fate of organic matter, nutrients and sediments in aquatic environments along with identification of robust numerical tools for advanced processing and modelling of 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 disturbances.

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.

Understanding the carbon cycle and ocean biogeochemistry, and how they relate to each other, is important for our understanding of the Earth’s environment in the past, present, and future. This session will discuss these interactions through different timescales and processes, from the ‘short-term’ biological pump to the ‘long-term’ burial in marine carbonates.
The ocean biological pump stores enough CO2 in the ocean interior to keep atmospheric pCO2 200ppm lower than it would otherwise be, with the depth at which this storage occurs being a key determinant of the size of this effect. This storage results from the surface production and interior respiration of organic matter, however, the transfer between surface and interior, and hence the depth at which remineralization occurs is driven by a wide array of processes including sinking, active fluxes, packaging of material by grazing, egestion and likely affected by plankton community composition and temperature. Understanding the relative importance of these processes is key to predicting the response of ocean biological C storage to climate change and human exploitation. The current intensification of human exploitation impacts on the ocean coupled with climate change is driving multiple projects (e.g. Ocean ICU, BioCarbon, Apero and Exports) to address these issues with the general objective of better predicting the evolution of future ocean C storage.
Ocean chemistry is linked to both short- and long-term C cycles via alkalinity input, saturation of carbonate minerals, and transfer of organic and inorganic C from the surface to the deep ocean. The sources and sinks of different elements and isotopes dictate their concentrations and isotope ratios in the ocean. Weathering and transport in rivers and reactions at mid-ocean ridges are major sources of elements to the ocean, while reactions with seafloor basalt, precipitation, scavenging, and adsorption onto particles are major sinks. These processes have also an important role in the C cycle. For example, silicate weathering removes CO2 and volcanism provides CO2 to the atmosphere over the long-term, and elements, such as Fe and Cd, are scavenged by the biological pump. Thus, studying oceanic geochemical budgets constrained by multiple isotope systems (e.g., δ11B, δ26Mg, δ30Si, δ88/86Sr) and concentrations (e.g., Fe, Sr, Ba, Li, S), and their variation over time, provides a useful tool in constraining the carbon cycle.

Marine heatwaves (MHWs) are discrete and prolonged warm ocean extremes that can cause substantial ecological and socio-economic impacts. Warming ocean temperatures due to climate change can be expected to exacerbate the severity of MHWs through the 21st century. Understanding of the physical mechanisms that generate MHWs is important to improving our capacity to forecast them. Meanwhile, gaining a better understanding of the impacts of MHWs on ecosystems is significant for promoting sustainable development in the face of climate change. We welcome abstract submissions across all aspects of marine heatwave research and particularly encourage submissions in the following areas:
• Processes and drivers of MHWs at the surface and subsurface: The role of local drivers and remote forcing in MHW generation and evolution.
• Methods for MHW detection and characterization: Discussion of MHW definition and ecologically based indices.
• MHWs in a changing climate: Projections of MHWs in the future under different scenarios.
• Historical analyses of MHWs: Process understanding of past pronounced MHW events and their impacts.
• MHWs and compound events: Interactions between MHWs and other systems (e.g., cyclonic storms, monsoons, and atmospheric heatwaves) or biogeochemical extremes.
• Ecological, socioeconomic, and biological impacts of MHWs.
• MHW predictability and prediction: Insights from advanced statistical methods, climate models, machine learning, etc.

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 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 and how fossil records shed light on ecosystem drivers over deep time. We aim to understand our planet and its biosphere through both observation- and modelling-based studies.

As the Earth's climate continues to change, rising temperatures and prolonged (seasonal) dry conditions are impacting vegetation and wildfire dynamics. Recent decades have witnessed an increase in the intensity, extent, and frequency of wildfires in fire-adapted regions and areas historically less prone to fires are now experiencing such events. Our understanding of vegetation and fire dynamics from in-situ observations and remote sensing is primarily limited to the past few decades. Palaeoclimate research gives insights into a wide range of interactions between climate, vegetation, and wildfires predating human land management. Documenting past vegetation and wildfire changes and inferring drivers and dynamics is of utmost importance for understanding ongoing and future changes of climate and continental ecosystems. Recent years have seen an increasing number of detailed reconstructions and significant improvement in model performance that allow fresh insights into spatio-temporal dynamics of ecosystems in response to climatic perturbations. Earth system models are increasingly used to understand the complex interactions between the biosphere and physical and biogeochemical components of the Earth system.

This session invites contributions on modern approaches to understand vegetation and wildfire dynamics during the Quaternary and their interactions with climate on seasonal to orbital timescales. These include but are not limited to (a) regional and global-scale reconstructions of vegetation cover and composition from paleontological and geochemical data, (b) the development and application of innovative proxies and archives, (c) Earth system model simulations of various time intervals, (d) studies combining data and models, and (e) proxy system modeling and novel statistical methods to constrain vegetation and wildfire dynamics and their drivers. We also welcome contributions related to technical and analytical advancements in organic and inorganic geochemical analyses, and in-situ calibration studies. Special attention is given to studies focusing on currently understudied regions and time intervals, and research that has the potential to inform future land management policies.

The planet is warming due to human-made greenhouse gas emissions, which have increased drastically since the industrial revolution. To grasp potential pathways for future climate, we need to understand what the impacts of elevated greenhouse gas emissions are on the global heat budget and how the climate system functions in conditions warmer than today. Geological archives and model simulations of past climate states are the key to better understanding climate dynamics in different, warmer-than-today climate conditions. Past warm climates also help to benchmark climate model simulations used to predict future climate and have contributed increasingly to successive IPCC reports.

In this session, we welcome contributions ranging from proxy data to model results aimed at reconstructing and understanding Earth’s climate state and its dynamics over the past 100 million years. We welcome submissions across a wide range of time scales, including those investigating long-term change, Milankovitch cyclicity and/or short-lived events, from the Cretaceous to the Present. Submissions working on chronological or stratigraphic fundamentals underpinning this interval are also encouraged. We invite contributions seeking to better assess Earth system sensitivity in past climate states by reconstructing atmospheric CO2 concentrations and global or regional temperatures. As analogues of biodiversity in a warmer world can only be found in the past, we encourage submissions on marine and terrestrial ecosystem dynamics and disruptions in warmer worlds.

The session intends to bring together the diverse community studying the nature of the warm climate states found in the Cretaceous and Cenozoic. This session also aims to bring together the paleoclimate data and modelling communities to evaluate lessons learned from the Deep-time Model Intercomparison Project (https://www.deepmip.org/) and explore future directions moving forward. We consciously welcome a broad range of approaches to facilitate synergies to learn from past warm climate conditions to navigate into the future warmer world.

Everywhere on Earth, microorganisms comprising bacteria, archaea, viruses, microalgae, and fungi, play vital roles in nutrient cycling and ecological balance. Microbial cells from surfaces are recurrently aerosolized, with the atmosphere playing a major role in their transport and redistribution on different temporal and spatial scales.
While extensive research has been dedicated to characterizing the cryo-, litho-, hydro-, and phyllo-spheres as microbial habitats, studies on atmospheric microorganisms have been limited to describing their abundance, diversity, and potential climatic and sanitary implications. However, the atmosphere is not merely an inert medium. Instead, it 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.
Describing microbial life in the atmosphere is crucial for comprehending drivers behind the atmospheric composition, processes and biogeochemical cycles. Furthermore, atmospheric microorganisms are closely interlinked with surface habitats, and can shape local, regional, and global processes impacting microbial biodiversity and biogeography. Thus, to gain a more complete understanding of the planet’s microbiome, it is important to identify chemical, physical and biological factors that shape and modulate atmospheric microbial populations, diversity, and functioning. Such factors include, e.g. emission/deposition from/to surfaces, exposure and response to stress factors such as concentration of atmospheric oxidants and the availability of water and nutrients, and the intrinsic biological traits of microorganisms.
This session will provide an interdisciplinary platform for all atmospheric scientists, biogeoscientists, and others that are concerned with transport processes of living microorganisms, microbial processes in the atmosphere and feedbacks on the Earth surface (water, soil, vegetation, ice). Contributions are encouraged that lead to a more comprehensive characterization of the microbiome and its interactions with the atmosphere and Earth’ surfaces. Studies are welcome that explore the atmospheric factors, processes and conditions that can affect atmospheric microbial diversity, concentrations, survival, and functioning.

In the last decades, the use of environmental magnetism in geophysical and geological sciences has increased. Environmental magnetism provides indispensable information about sedimentary and tectonic processes, environmental redox conditions during sedimentation, diagenesis, and biological activity among others. The purpose of this session is to integrate diverse applications of environmental magnetism in the domain of geosciences

Methane is of utmost importance as a greenhouse gas in the atmosphere, and we know that the majority of environmental methane is produced — and consumed — in sediments and the water column of marine and lacustrine systems. Nevertheless, 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 and biological factors.
In this session we will discuss controls on methane dynamics in marine and lacustrine 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 diffusive transport mechanisms to advective fluxes and bubble releases
- methane sinks: from microbes and biogeochemical pathways and kinetics to physicochemical processes
- methane and element cycling: from interactions with the carbon-, sulphur-, and nitrogen cycle to trace metals and involved biota
- methane ecosystems: from symbioses to methane-fuelled food webs
- methane timescales: variations on diel, seasonal, and geological time scales
- methane geobiology: methane-derived carbonates, microbe-mineral interactions, and molecular/micro/macro fossils.
- methane in silico: modelling methane dynamics from molecular to planetary scales and deep time to the far future.

Water is the defining feature of the habitable Earth; it is essential for all life as we know it. Evolution and maintenance of life in extremely water limited environments, which cover significant portions of the Earth, is not well understood. Akin to life, water-driven processes leave unique marks on the Earth’s surface. Mars is the only other planet currently known to bear the marks of water-driven surface processes, albeit fossil and of great age. The slow biotic and abiotic surface processes that may operate even in the virtual absence of liquid water are still essentially unknown. What is evident is that transient episodes of increased water availability can leave long lasting traces in extremely water limited environments. Intriguingly, those traces of bursts in Earth surface evolution have rarely been related to bursts in biological colonization/evolution, and vice versa, although both relate to the same trigger: water.
The objective of this session is to showcase research on the mutual evolutionary relationships between Earth surface processes and biota in arid to hyper-arid systems, where both biota and Earth surface process are severely and predominantly limited by the availability of water (rather than by extreme temperatures). As the robust quantification of rates and fluxes in desert landscapes is one of the key challenges related to research at the Earth´s dry limit we highly welcome cutting-edge contributions from geochemistry, biogeosciences, geology, geomorphology and geochronology. We especially encourage contributions from early career scientists who work at the intersection of Earth surface processes and biological evolution.

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.

Geoscience knowledge and practices are essential for effectively navigating the complexities of the modern world. They play a critical role in addressing urgent global challenges on a planetary scale (including, climate change and its social, humanitarian, and health impacts), informing decision-making processes and guiding education at all levels. However, the response to these challenges remains largely inadequate across the board.
By equipping both citizens and the wider societal stakeholders with the necessary knowledge background, geosciences empower them to engage in meaningful discussions, shape policies, contribute to reduce inequities and injustice, and implement solutions for local, regional, and global social-environmental problems. Within this broad scope, geoethics strives to establish a shared ethical framework that guides geoscientists’ engagement with sensitive and significant issues concerning the interaction between geoscience and society.
This session will cover a variety of topics, including theoretical and practical aspects of geoethics, ethical issues in professional practice, climate and ocean education, geoscience communication, and strategies for bridging the gap between geosciences and society.
This session is co-sponsored by the International Association for Promoting Geoethics, the Commission on Geoethics of the International Union of Geological Sciences and the Chair on Geoethics of the International Council for Philosophy and Human Sciences (www.geoethics.org).