Topics & Program

In this session, we will examine the various biogenic impacts at different scales on surface sediments and their influence on sediment-water exchanges. This topic encompasses both the interactions between bacteria and primary producers within their sedimentary environment (such as oxic/anoxic conditions, the impact of plant roots, and the migration of microphytobenthos organisms), as well as the role of animal organisms, particularly through their sediment reworking activities. Moreover, this session will not only focus on the biogenic impacts on sediments but will also consider the reciprocal feedbacks, specifically how the sediment characteristics and their geochemical environment affect the organisms present.

This session will focus on sediment management in freshwater and coastal zones, areas that have been significantly impacted by human activity and changing climatic conditions. These alterations have profound effects on contaminant and nutrient fluxes at the water-sediment interface. The session will also address the issue of contaminants within sediments, considering the potential for sediments to be repurposed and valorised as new materials.

This session will explore the latest advancements in assessing and restoring disturbed catchments, focusing on the ecological, hydrological, and sedimentological impacts of disturbances such as land-use changes, pollution, and climate change. Topics will include innovative techniques for evaluating catchment health, monitoring ecosystem recovery, and understanding the interactions between water quality, sediment dynamics, and biodiversity. Restoration strategies, including natural-based solutions and engineered approaches, will be discussed, with a focus on their effectiveness in promoting resilience and sustainability. Case studies from diverse environments will highlight best practices, challenges, and opportunities in restoring disturbed catchments. The session aims to foster dialogue on emerging tools and interdisciplinary approaches essential for effective catchment management in the face of ongoing environmental pressures.

This session will focus on emerging contaminants (ECs) characterized by limited data on their presence, fate and toxicological effects, as well as limited regulations. They include a wide range of substances from various anthropogenic activities, which have received increased attention in recent years, including pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), microplastics, nanomaterials, pesticides and endocrine-disrupting chemicals. Presentations will focus on sediments as sources and sinks of ECs. This includes the identification of pollution sources, transport dynamics, time series and/or spatial distribution of contaminated sediments. Sediments also play an essential role in the transformation, speciation, sorption and persistence of contaminants. Presentations on these aspects, possibly combined with modeling, are also part of the theme of this session. Finally, this session would welcome work on analytical procedures and methods for assessing ECs in sediment.

This session will focus on the effect of extreme events (floods, wildfires, droughts, heatwaves...) on the environment and the functioning of extreme environments (i.e. environments that differ in one or more aspects from those considered as “normal,” moderate conditions with circumneutral pH, moderate temperatures, pressures, and adequate concentrations of nutrient and saline). The question will be to understand how extreme events lead to changes or decline of environmental functions. Presentations will focus on the potential of extreme events to alter watershed processes and stream response, in terms of sediment transport, soil and water characteristics and chemistry. Topics will refer to the potential impacts of climate-related extreme events on different water quality indicators and the potential impact of cascading extreme events (e.g., drought-flood regimes) on dynamics of water quality behavior, coastal sediment budgets and landscape morphology. Presentations on concentrations, discharge and flux of suspended sediment, major ions, dissolved organic carbon (DOC) and key nutrients (NO3 and PO4) following such extreme events or any process or budget in extreme environments are also part of this session.

Anthropogenic activities and changes in hydrological dynamics have a major impact on surface water quality. From watershed to the coastal environment, organic matter (OM) comes from a wide variety of sources, and its inputs are increasing. Whether in dissolved, colloidal or particulate form, OM plays a major role in the dynamics, transport, potential transformation and fate of contaminants such as trace metals. Photo-biodegradation processes affect dissolved OM quantitatively and qualitatively and thus influence the speciation and bioavailability of contaminants.

In this session, contributions on perturbed biogeochemical processes in aquatic and coastal interface systems are welcome, as well as studies on the spatio-temporal evolution of contaminants induced by OM dynamics.  Observational, experimental and/or modelling approaches will provide a better understanding of the processes influencing water quality along the catchment-river-sea continuum.

This session will delve into the emerging field of rewilding and restoration in coastal areas, addressing the critical need for ecosystem recovery in the face of human impact and climate change. Key topics will include the restoration of critical habitats such as saltmarshes, seagrass beds, and mangroves, and the reintroduction of native species to enhance biodiversity and ecosystem function. We will explore the role of natural processes, such as sediment dynamics and ecological interactions, in fostering long-term resilience. Case studies will highlight innovative rewilding projects and restoration strategies, from local initiatives to large-scale efforts. The session will foster discussion on the challenges, opportunities, and future directions for rewilding coastal environments as a tool for climate change mitigation and biodiversity conservation.

This session will focus on the role of blue carbon ecosystems, such as mangroves, seagrasses, and saltmarshes, in carbon sequestration and their significant contribution to global carbon budgets. We will explore the mechanisms through which these ecosystems capture and store carbon, as well as the factors that influence their carbon storage potential. Key topics will include methodologies for accurately quantifying carbon stocks in blue carbon habitats, the challenges in measuring and monitoring carbon fluxes, and the implications for climate change mitigation strategies. The session will also address the impact of environmental degradation, such as coastal development and pollution, on the carbon sequestration capacity of these ecosystems. Furthermore, we will examine restoration efforts aimed at enhancing blue carbon stocks and the integration of blue carbon into national and international carbon accounting systems. Through case studies, the session will highlight successful projects, as well as the potential for scaling up blue carbon initiatives to support global climate targets. Ultimately, this session will provide a platform for discussing innovative approaches and future research directions in the field of blue carbon and carbon budgeting.

This session will focus on the critical issue of coastal erosion, exploring its drivers, impacts, and the range of solutions available to mitigate and manage this growing challenge. We will examine the various natural and anthropogenic factors contributing to coastal erosion, including climate change, rising sea levels, and human activities such as coastal development and land use changes. The session will highlight cutting-edge research on the processes of coastal erosion, with a particular focus on sediment dynamics and geomorphological changes. A key theme will be the effectiveness of different coastal protection strategies, from hard engineering solutions like sea walls and groynes to softer, nature-based approaches such as beach nourishment and dune restoration. Case studies will demonstrate the success and limitations of these strategies in different coastal environments, providing valuable insights into adaptive management practices. The session will also consider the social and economic implications of coastal erosion, including impacts on communities, infrastructure, and biodiversity. Participants will have the opportunity to discuss innovative approaches, policy frameworks, and future research directions to ensure sustainable and resilient coastal management in the face of ongoing environmental pressures.

This session will delve into the modeling of suspended particles and aquatic sediments, critical components influencing aquatic ecosystems and water quality. Presentations will explore sediment transport processes, particle dynamics, and interactions between sediments and pollutants, including adsorption, deposition, and resuspension. Contributions addressing the physical, chemical, and biological processes affecting sediment behavior in diverse aquatic environments are encouraged. Topics may include hydrodynamic modeling, sediment flux quantification, and the role of sediments in nutrient cycling. The session also invites studies integrating modeling approaches with field or laboratory data, as well as spatio-temporal analyses of sediment processes.

This session will focus on the hyporheic zone, made up of interfaces between surface water and groundwater, the functions and behaviors of which are still poorly understood. Presentations will focus on the fluxes of pollutants (nutrient salts, metals, organic pollutants and associated metabolites, etc.) and organic matter at interfaces (diffusion, convection, bioturbation, etc.) and the degradation and speciation of substances during early diagenesis. This zone also plays an important role in water quality during lateral and transverse hydrological transport. Presentations on these aspects, possibly coupled with modeling, are also part of the theme of this session. Finally, this zone has a complex ecological functioning, with benthic species playing a crucial role in the regulation of this zone in bottom sediments and biofilms. Studies on their behavior and roles within the hyporheic zone are expected. Finally, this session would welcome work on spatio-temporal evolutions.

As a sediment researcher, nutrient (P and N) specialist, or someone studying eutrophication and cyanobacteria proliferation in lakes world-wide, we invite you to participate in this special session.

More and more knowledge has come to light that involves legacy nutrients in lake sediments in the proliferation of cyanobacteria (e.g., www.routledge.com/9781032294407). In conjunction with increased development and climate change (including increases of air temperature, drought, and storm events), sediment-derived nutrients (especially phosphorus, but also nitrogen) may give a boost to cyanobacteria proliferation at important times.

We welcome studies that critically test the whole or parts of the hypothesis that a major contributing factor to the recent increase in cyanobacteria bloom expansion and frequency is internal phosphorus loading as intensified by climate change. Case studies, meta-analyses, and theoretical efforts are welcome.

Session Chairs:

Gertrud Nürnberg, Freshwater Research, Baysville, Ontario, Canada <gkn@fwr.ca>

Olga Tammeorg, University of Helsinki, Finland <olga.tammeorg@helsinki.fi>

Please direct any comments and questions to the chairs directly. (A special issue of attendants’ papers is possible.)

All topics related to water-sediment interactions which do not correspond to any of the themes of the other sessions. Despite numerous themes covering fairly broad themes, if certain subjects are not in line with these themes and are suggested by several proposals, we will group the interventions.