The last two decades have brought a major technological advancement in collection of water quality and biogeochemical data in rivers, lakes and engineered systems using automated in situ wet-chemistry analysers, optical sensors and lab-on-a-chip instruments. Furthermore, our ability to characterise different fractions of natural organic matter has increased thanks to a range of analytical methods e.g. fluorescence and absorbance spectroscopy, mass spectrometry and chromatography combined with new data mining tools (Self-organising maps, PARAFAC analysis). Matching the water quality measurement interval with the timescales of hydrological responses (from minutes to hours) led to discovery of new hydrochemical and biogeochemical patterns in streams along with improved understanding of the underlying processes e.g. concentration-discharge hysteresis and diurnal cycling. We are now at the frontier of further advancing this understanding for a wide range of solutes and particulates in streams, rivers and lakes using rapidly developing technology of wet-chemistry analysers, optical sensors and lab-on-the-chip instruments. We need to understand better how organic matter links with other biogeochemical cycles (e.g. phosphorus, nitrogen, sulphur and iron) and processes in aquatic systems. In particular there is a growing need to monitor the advances in application of novel organic matter characterisation tools, understanding the origins, pathways, transformations and environmental fate of organic matter in aquatic environments and identification of robust numerical and statistical tools for data processing and modelling. This is an exciting opportunity to gain new knowledge of hydrochemical and ecological functioning of freshwater and engineered systems.

Previously in this session:
EGU 2018:
https://meetingorganizer.copernicus.org/EGU2018/session/26401

EGU 2017:
http://meetingorganizer.copernicus.org/EGU2017/session/24958

EGU 2016:
http://meetingorganizer.copernicus.org/EGU2016/session/20013

EGU 2015:
http://meetingorganizer.copernicus.org/EGU2015/session/17101
Keynote lecture: Diane McKnight

EGU 2014:
http://meetingorganizer.copernicus.org/EGU2014/session/15261
Keynote lecture: Darren Reynolds

According to the Stockholm Convention on persistent organic pollutants (POPs), these compounds are resistant to chemical, biological, and photolytic environmental degradation. POPs are stable and persistent, long-distance transportable, bioaccumulative, biomagnifiable in the food chain, and could pose significant impact on human health and the environment. Currently, there is a rising concern about the presence of new organic synthetic compounds in the environment, the so-called new or emerging contaminants, which include the emerging POPs (ePOPs) that are either, very recently or not yet regulated.
Research about the source, occurrence, distribution, fate and toxicity of ePOPs is pivotal for understanding their impact and environmental behavior. The final destiny of most of ePOPs is water or aquatic ecosystems, which can be reached in different ways: improper disposal, release through domestic wastewater systems, through agriculture and industry or after passing through wastewater treatment plants that do not effectively eliminate them. Once ePOPs are released into waterbodies, they may also come into contact with solid particulate matter (suspended or deposited in sediment, which is considered as a sink of many POPs) or they can be bioaccumulated in aquatic organisms, and finally in humans.
In 2009, polybrominated diphenyl ethers (PBDEs) and perfluorooctane sulfonyl fluoride/perfluorooctane sulfonate (POSF/PFOS) were added to the list of Stockholm Convention and hexabromocyclododecanes (HBCDs) listed as candidate. The ePOPs include these substances as well as several others widely used in industrial processes and consumer products, such as perfluoroalkyl substances (PFASs), non-PBDEs or novel brominated flame retardants (NBFRs), organophosphate flame retardants (PFRs), dechlorane plus and related compounds, short-chain chlorinated paraffin and GenX that have been proposed as a replacement alternative for banned formulations.
It is a vital scientific challenge to disentangle the impact of human development and its relationship with the presence of ePOPs in aquatic ecosystems, as well as their possible effects on populations that source their waters or organisms that inhabit them. This session aims at giving an overview of the current research and state of knowledge on contamination of these ecosystems with ePOPs and identifying the factors affecting their distribution and fate, as well as examples of sustainable mitigation/remediation practices, and research needs, that help to regulate and control ePOPs contamination of aquatic ecosystems. Contributions from all areas of biogeosciences: biology, ecology, chemistry (analytical, bio, environmental, …), toxicology, etc. are invited to contribute to this multidisciplinary session.

Inland waters and wetlands (both brackish and fresh) form networks that represent vital conduits through the landscape; receiving, transporting, transforming and emitting carbon. To better constrain the role of freshwater networks within the global carbon cycle, it is pivotal to study the exchange and transformation processes that take place at interfaces, both between the network’s aquatic compartments (as e.g., between anoxic and oxic waters) but also conterminous to the terrestrial and atmospheric realm (e.g., sediment-water, water-air). Such interfaces feature distinct physical and biogeochemical gradients and often represent biogeochemical “hot spots” in the landscape.

In this session, we will address the biological, biogeochemical and physical processes that control the cycling of carbon at aquatic interfaces, especially with regard to the formation and emission of the greenhouse gases CO2 and CH4, and associated redox driven processes.

We invite presentations on recent empirical and conceptual advancements at the forefront of carbon cycling along the land to ocean aquatic continuum, with a focus on processes that occur at aquatic interfaces. We encourage contributions that employ novel biogeochemical, molecular biological and modeling approaches directed towards obtaining a fundamental and mechanistic understanding of the active controls on carbon processing and storage across freshwater ecosystems.

Groundwater-surface water interfaces (e.g., hyporheic and benthic zones and riparian corridors) are integral components of the aquifer-river or aquifer-lake continuum. Interactions between groundwater and surface water lead to strong bi-directional influences between surface waters, aquifers and interconnecting hyporheic zones. A rapidly expanding number of research projects are now investigating the implications of hyporheic exchange on the transport and transformation of nutrients and contaminants within river networks, and on controls to heat, oxygen, and organic matter budgets available to microorganisms and macroinvertebrates in streambed sediments. However, there is still a need to better understand the links between physical, biogeochemical, and ecological process dynamics in groundwater-surface water interfaces and their implications for fluvial ecology or limnology, respectively. Furthermore, it is important to consider the response of hyporheic exchange fluxes to environmental and climatic controls at different spatial and temporal scales (e.g. river channel, alluvial aquifer, regional groundwater flow). We consider up- and downscaling and the development of a general conceptual framework and improved process understanding for groundwater-surface water interfaces as among the most urgent challenges of hyporheic zone research. Consequently, we particularly welcome contributions that aim to close these knowledge gaps and solicit both experimental and modelling studies with a focus on:

- The development and application of novel experimental methods to investigate physical, biogeochemical and ecological conditions at the groundwater-surface water interface in rivers, lakes, riparian corridors, and wetlands;

- Investigations of the role of hyporheic processes for the retention and natural attenuation of nutrients and pollutants, particularly with respect to impacts on surface water and groundwater quality;

- Hydrological, biogeochemical and ecological modelling approaches (e.g. transient storage models, coupled groundwater-surface water models etc.);

- Investigations of the implications of groundwater-surface water interactions for management and risk assessment frameworks with regard to the European Water Framework Directive.

In recent years there has been a growing emergence of interdisciplinary research areas concerned with investigating the dynamic and multifaceted interactions between biotic and abiotic components of aquatic ecosystems. Such is the acknowledged importance of these interactions, that quantifying and understanding the two-way feedbacks of interacting abiotic and biotic components is recognised as a key contemporary research challenge. However, the different terminology used by various disciplines highlights the separation rather than the overlap between disciplines. Further, in many instances the creation of new sub-disciplines (or research areas) is not developing the study field, but arguably is leading to the ‘reinvention of the wheel’ in parallel disciplines. Changing the traditional perspectives by bridging the gaps between disciplines is therefore key to bring considerable advances in aquatic research.
This session focuses on bringing together scientists from different backgrounds dealing with the effects of environmental (both biotic and abiotic) stressors on the aquatic biosphere, from individual organisms through to whole ecosystems with the aim of simulating truly interdisciplinary research. Several temporal scales ranging from a single event (e.g. response to hydropeaking, predatory attacks) to long term evolution (e.g. adaptation to climate change, ecosystem modification) may be considered. We expect strong contributions from researchers transcending a variety of disciplines such as geomorphology, engineering, ecology and environmental sciences. Emphasis is given to studies dealing with stressors driven by climate change or anthropogenic activities. In this context we particularly welcome contributions on consolidated or novel measurement techniques and modelling tools to assess the effects of environmental stressors (e.g. flow modifications, habitat alterations) on biota, such as vegetation, macroinvertebrates and fish, that cross disciplinary boundaries.

The session will include an invited keynote by Prof. Markus Holzner from ETH Zürich.

This session provides a scientific platform for exchange of findings from research that addresses the entire continuum of river and sea. We invite studies across geographical borders, along the freshwater-marine water continuum, and interdisciplinary studies that integrate physical, chemical, biological, geological observations/experiments, and modelling, and those that span the traditional silos of natural and social sciences.
River-Sea-Systems comprise river catchments, estuaries/deltas, lagoons and the coastal seas. They are dynamic products of interacting environmental and socio-economic processes. River-Sea-Systems provide natural capital and related ecosystem services that are fundamental to societal wellbeing. These systems, however, face compounding pressures from natural forces such as climate change and natural hazards, and from anthropogenic forces like urbanisation, shipping, energy generation, industrial development, water abstraction and damming, operating at local, national and global scales. The resulting pressures contribute to societal challenges such as eutrophication, hypoxia, pollution, change in hydrodynamics and morphodynamics (including disturbed sediment balances), loss of biodiversity, habitat depletion, sea level rise, and ultimately loss of ecosystem services. This impacts not only on the ‘planet’ but also on ‘people’ and ‘profit’. These pressures are likely to increase in the future with implications throughout the river-sea continuum with uncertain consequences for the resilience of the socio-ecological system.
We need to fully understand how River-Sea-Systems function. How are River-Sea-Systems changing due to human pressures? What is the impact of processes in the catchment on marine systems function, and vice versa? How can we discern between human-induced changes or those driven by natural processes from climate-induced variability? What will the tipping points of socio-ecologic system states be and what will they look like? How can we better characterise river-sea systems from the latest generation Earth observation to citizen science based observatories. How can we predict short and long term changes in River-Sea-Systems to manage them sustainably? What is the limit to which it is possible to predict the natural and human-influenced evolution of River-Sea-Systems?
Which policy responses would be desirable from a scientific perspective and how will the gaps between the existing European environmental policies be bridged (e.g. Water Framework Directive 2000, Marine Strategy Framework Directive 2008 and EU biodiversity policies)? How will links be made to the UN 2030 Agenda’s Sustainable Development Goals 6 (Clean Water & Sanitation) and 14 (Life below Water)?
The increasing demand to jointly enable intensive human use and environmental protection in river-sea systems requires holistic and integrative research approaches with the ultimate goal of enhanced system understanding. It is becoming widely recognised that there is a need to study River-Sea-Systems as an entire continuum, to provide scientifically underpinned information to enable better-informed and holistically engaged environmental protection of River-Sea systems, to maintain their ecosystem functioning and thus their capacity to provide ecosystem services.

Coastal wetland ecosystems, such as salt marshes, mangroves, seagrasses and tidal flats, are under increasing pressure and threat from natural and anthropogenic processes such as land claim, altered sediment regimes, increased storm magnitude and frequency, and relative sea level rise. Consequently, these ecosystems are declining globally, with evidence of degradation and isolation across the full variety of coastal wetland habitats. These environments provide numerous ecosystem services, including flood risk mediation, biodiversity provision and climate change mitigation through carbon storage. There is, therefore, a need to understand current processes and interactions in these environments, and how these may change in the future due to both natural and anthropogenic influences. This is particularly the case in ‘managed’ and restored wetlands, where tidal and/or riverine regimes are re-introduced and coastal wetlands allowed to migrate inland in response to sea level rise for the provision of the desired ecosystem services to be preserved and/or restored.
This session will bring together studies of coastal wetland ecosystems within open coast, estuarine, lagoon and delta environments, to enhance the understanding of the services provided, interactions between hydrodynamic conditions, sediment and ecology, and best future management practices. Studies of all processes occurring within coastal wetlands are invited. This includes, but is not exclusive to, sediment dynamics, hydrology, hydrodynamics, morphological characterisation, geotechnical analysis, ecological change and evolution, impact of climate change, sea level rise, anthropogenic and management implications. Multidisciplinary approaches and studies of wetland restoration and habitat loss compensation schemes are particularly encouraged, along with global to regional assessments of wetland migratory potential; studies on wetland migration dynamics and the characteristics and functions of restored wetlands; and governance and policy contexts for wetland migration. This session aims to enhance our understanding of wetland management, processes, interactions and the wetlands’ ability to migrate inland, allowing for improvement of our ability to quantify the responses of coastal wetlands and their ecosystem services to future sea level rise and anthropogenic activity.