Wednesday 24th September 2025
Coupling Components
Session 1: Integrating Ecological Models with Physical and Biogeochemical Processes
This session focuses on modelling approaches for marine and coastal higher trophic levels, their use of ocean and biogeochemical model output, and advancing the integration of ecological processes into coastal models. Key themes include trophic feedbacks, habitat–species interactions and environmental driving of biological dynamics, and assessing anthropogenic impacts through fisheries and climate change. It examines the integration of ecological models with physical and biogeochemical components, with special attention to cross-scale interactions (e.g. larval dispersal to living marine resource productivity), ecological thresholds, and the calibration of models to empirical data and their projection into the future. These models provide important decision support in resource and ecosystem-based governance and societal adaptation to climate change. Guiding question: Which ecological drivers and resolutions are most critical for linking coastal ecosystems with large scale processes, and how can such coupled models best be validated against empirical data?
Chair: Kenny Rose (University of Maryland, USA)
09:00–09:30 – Keynote: Edward Gross (GEI Consultants, USA)
Estimating rate parameters in ecological models utilizing novel representations of transport processes
Ecological models and biogeochemical models use a variety of methods to represent transport processes. I will present two novel and computationally efficient approaches to infer parameters in ecological models driven by information on hydrodynamic transport in the San Francisco Estuary. First, movement information from a particle-tracking model was utilized for Bayesian inference of hatching distributions of the endangered longfin smelt Spirinchus thaleichthys in the estuary. This understanding informs management actions intended to minimize entrainment of larvae by water diversions. Second, rates in an offline biogeochemical model were inferred using scalar concentration and age distributions computed by a hydrodynamic model. The analysis revealed that uptake of nutrients by aquatic vegetation was a key biogeochemical process that had been overlooked by previous models. The examples demonstrate that simplified representations of transport processes are useful to infer unknown ecological rates. These rates can be used in more complex coupled hydrodynamic-ecological models.
09:30–09:45 – Alonso Del Solar Escardó (ZMT)
Co-designing Adaptation Pathways for Peru’s Coastal Systems under Compound Drivers: Linking Ecological Modelling, Climate Projections, and Stakeholder Insights
Peru’s rich, interconnected coastal systems face compound pressures from climate variability and human use. Combining trophic modelling (EwE) with stakeholder insights, this talk explores ecosystem drivers – from ecological responses and masked heatwave feedbacks to market forces and trade-offs – and the emerging challenges and adaptation strategies for local actors. We updated models for two bays (Sechura, Independencia) and the offshore pelagic–demersal system, grounding testable scenarios with historical time series, downscaled ocean–biogeochemical projections, and stakeholder engagement. This enables cross-ecosystem comparisons and supports co-designed scenarios under shared socio-economic pathways. In Sechura, exposure to El Niño, hypoxia, and scallop over-stocking reveals tensions between resilience and human needs. Next steps are to pinpoint the key ecological and socio-economic drivers and system responses, refine and validate scenarios using targeted indicators and broader stakeholder input, and translate results into decision-support tools at appropriate scales to co-design adaptation pathways that balance ecosystem health with livelihoods.
09:45–10:00 – Kenny Rose (University of Maryland, USA)
Some Issues Related to Coupling Physical/Biogeochemical and Upper Trophic Level Models: Fallacy of Averaged Values, Incompatible Spatial Resolutions, and Nervous Skill Assessment
I will discuss three issues related to coupling physical and biogeochemical models (lower trophic level, LTL) to upper trophic levels. These issues are: (1) transferring more than the average values from ESM to LTL to upper trophic level models should be considered, (2) matching of the spatial resolutions of the ESM, LTL and upper trophic models should start by considering the dynamics of the upper trophic levels (i.e., top down), and (3) challenges to skill assessment posed by the different scales and expectations of LTL and upper tropic level models, especially under novel conditions. These issues will be discussed in general terms and illustrated with examples, including coupled LTL-upper trophic models of sardine and anchovy population dynamics in the California Current and anchovy recruitment in the Humboldt Current off Peru. Possible solutions to these issues will be discussed.
10:00–10:15 – Ken Andersen (Technical University of Denmark)
How can size-spectrum and trait-based models advance the integration of marine ecosystem dynamics into Earth System Models? Towards a broader perspective on ecological modelling across scales
We are currently challenged to model how climate change affects higher trophic levels, such as fish. Traditional fish models are food-web models that describe all species in a region and their predator-prey interactions. These models work well for describing the impacts of fishing on the community, but struggle with climate change impacts because they do not resolve the crucial effect of species invasions and their reliance on stock-recruitment relationships. Here I present the “FEISTY” size- and trait- based fish community model that explicitly resolves the dependence of fish on pelagic and benthic energy pathways that can be provided by standard lower-trophic-level models. The model framework predicts emergent food-web structure, potential fisheries production, and carbon sequestration under climate change scenarios on a global scale. I discuss pros and cons of different strategies for coupling the lower-trophic-level models to higher trophic level models.
10:15–10:30 – ZMT’s Senior Scientists (~2 min each)
TropEcS Topics in a Nutshell: Speed Talks about Posters on Display
TropEcS brings together expertise from the natural and social sciences to improve the model representation of tropical coastal ecosystems under global change. This session features a series of speed talks that introduce the diverse research topics and model components addressed within TropEcS. The talks provide a preview of posters on display during the session breaks, where the individual contributions can be explored in greater detail and discussed directly with the researchers.
Esteban Acevedo-Trejos (ZMT)
Earth Surface and Eco-Evolutionary Dynamics Group
Life, climate, and landforms interact to shape the patterns of biodiversity we observe on the Earth’s surface. Models serve as valuable tools for testing our intuitions of how these complex systems form and function. While advances have been made in modelling these system components, the focus is typically on just one – either the landscape, climate, or eco-evolutionary part. Hence, to continue investigating how these components interact, there is a need to develop coupled numerical tools. In my contribution, I outline the research focus of the recently established Earth Surface and Eco-Evolutionary Dynamics Group at ZMT, which aims to develop coupled numerical models to explore how geophysical processes influence functional diversity and how trait variability impacts biogeomorphic systems. The proposed modelling approach is illustrated with potential applications in two research foci. The first focus looks into long-term dynamics, such as mountain-building processes (i.e. surface uplift and erosion), and how such processes affect the morphology of volcanic islands and biodiversity. The second centres on short-term dynamics such as river delta formation, emphasising how trait variability and the unresolved role of organic sediments affect the morphology and sediment composition of deltas. Future directions involve establishing a dedicated modelling group at ZMT, where the development of coupled numerical tools to capture feedbacks between Earth system components at local/short-term and regional/long-term scales will be central. This interdisciplinary approach ultimately aims to advance knowledge of Earth system components’ interactions and their influence on biodiversity, thus contributing to a deeper understanding of the dynamic relationships between life and the physical environment.
Carbon and Nitrogen Dynamics in Rivers: Modelling Oceanic Yields and Atmospheric Emissions
Tropical coastal ecosystems are shaped by complex interactions between terrestrial, aquatic, and socio-economic processes. Understanding carbon and nutrient fluxes across the land–ocean continuum is essential for assessing greenhouse gas emissions, ecosystem functioning, and the impacts of land-use change. This poster presents planned research within the TropEcS framework at ZMT, focusing on carbon and nitrogen dynamics in tropical peat-draining rivers and wetlands. I aim to improve their representation in the ORCHIDEE land surface model by integrating process understanding from field studies in Southeast Asia, which showed how peat extent and pH regulate riverine carbon dioxide and oxygen dynamics. This work will be implemented in a model version with river routing, with extensions planned to include peatland methane processes and nitrogen fluxes.
Land–Ocean Fluxes and Transformations
Current Earth System Models treat land and ocean as largely disconnected systems, with freshwater discharge as the most explicitly represented link. Their coarse spatial resolution overlooks key coastal features such as tidal rivers, estuaries, wetlands, submarine groundwater discharge, and subterranean estuaries, and limits the representation of subsurface and biogeochemical processes at the land–sea interface. To address this, we are developing a physically based model that will couple surface and subsurface water flow with reactive transport of carbon and nutrients. The goal is to more accurately quantify material fluxes across land–ocean boundaries, incorporating both flow pathways and transformation processes. Scenario-based simulations will be used to explore how these fluxes respond to socio-economic drivers.
Understanding the Biogeography of the Cyanobacterial N2 fixer UCYN-A
Biological nitrogen (N₂) fixation is essential for sustaining marine productivity, yet most ocean surface waters are depleted in bioavailable nitrogen. Among marine diazotrophs, the unicellular cyanobacterium UCYN-A is one of the most widespread and ecologically important contributors to oceanic nitrogen input. UCYN-A was long considered an obligate symbiont of the haptophyte Braarudosphaera bigelowii, but recent work suggests that the UCYN-A2 sublineage exhibits traits of an early-stage organelle. Despite its ecological importance, UCYN-A is difficult to culture in the laboratory, leaving its physiology and global distribution poorly understood. Here, we integrate new experimental data with a cell-based mathematical model to explore how intracellular regulation of carbon and nitrogen exchange governs N₂ fixation in the UCYN-A/haptophyte association. The model explains its persistence under low light and across a broad thermal range, supporting activity across depths and latitudes. Our simulations predict high fixation in the Atlantic and Indian Oceans, patchy distributions in the Pacific, and strong seasonal patterns at high latitudes driven by temperature, with iron emerging as the dominant control in the tropics. Together, these results provide a mechanistic framework linking UCYN-A cell physiology to its global biogeography.
Stefan Koenigstein (ZMT)
The devil’s in the details when linking marine fish to ocean environments
Marine fisheries provide food and livelihoods to about one billion people globally. Earth system and ocean-biogeochemical (BGC) models can be used to drive ecological models of marine fish populations, to support sustainable fisheries governance, global food security and climate change adaptation. However, the characteristics of biological systems and some technical challenges complicate the coupling of ocean and fish models: For instance, high spatial and temporal resolution is needed to model fish habitats shaped by fine-scale ocean and coastal features such as fronts, eddies, and river plumes. Linking phyto- and zooplankton productivity and mortality in BGC models to fish consumption currently constitutes a major uncertainty. Migration and behavioral adaptation, distinct environmental preferences among life stages, food-web interactions, and evolutionary adaptation further complicate fish responses to the environment. Furthermore, especially in many tropical areas, fish observational data is typically patchy and uncertain, and fisheries landings are strongly influenced by socio-economic drivers. To overcome the challenges, coupled models need to consider biological detail and bridge among disciplines, to advance understanding of marine fish productivity, spatial distribution, and sensitivity to fisheries, and robustly project the impacts of global change.
Camilla Novaglio (ZMT)
Modelling Ocean Futures for Fisheries and Food Security
Marine ecosystems and fisheries are increasingly threatened by climate change and resource exploitation, with profound implications for food security and livelihoods, particularly in the tropics. Although these regions are highly dependent on fisheries, they remain underrepresented in modelling efforts that are essential for understanding ecosystem dynamics and anticipating ecological shifts. The Ocean Futures and Fisheries Modelling working group applies marine ecosystem models to investigate how tropical ecosystems and fisheries may respond to alternative climate and resource use scenarios. By integrating ecological and human dimensions, we assess strategies that balance environmental sustainability with socio-economic resilience. In addition, model outputs are combined with aquaculture and agriculture projections, as well as socio-economic data, to evaluate climate risks to integrated food systems, identify cross-sectoral trade-offs, and inform policy. Through collaborations with initiatives such as the Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP) and FAO the group advances modelling capacity in the Global South and provides science-based guidance for sustainable, climate-ready food systems.
Michael Kriegl, Annette Breckwoldt (ZMT)
Participatory Modelling of Social-Ecological Systems
Millions of people in tropical coastal regions depend on healthy marine ecosystems for their livelihoods. Yet the models that inform environmental management and policy rarely reflect the perspectives of coastal communities. Including local voices into modelling efforts is essential to co-produce knowledge that is not only scientifically robust but also contextually relevant. Within TropEcS, integrated participatory modelling will be advanced across Peru, Colombia and Indonesia, using three complementary approaches: 1) Co-developing interdisciplinary qualitative network models with local actors to identify drivers, feedbacks, and leverage points in social-ecological systems (fisheries, aquaculture, tourism and conservation). 2) Facilitating scenario-building through drawing workshops to elicit visual narratives of desired futures. 3) Applying Bayesian Belief Networks to integrate diverse knowledge systems and TropEcS model results into accessible decision-making tools for data-limited contexts. Embedding local perspectives throughout TropEcS seeks to ensure that its outputs have a positive impact on both communities and the ecosystems they rely on.
Poster by our partners: Heidi Retnoningtyas, Irfan Yulianto (Rekam, Indonesia)
Implementing Ecosystem-Based Fisheries Management (EBFM) in Indonesia: A case study from Saleh Bay
Ecosystem-based approaches to fishery management examine how fisheries integrate with ecological and human considerations to achieve acceptable sustainability. Implementing Ecosystem-Based Fisheries Management (EBFM) in tropical small-scale fisheries presents significant challenges, particularly in multispecies and multigear contexts such as those found throughout Asia. Indonesia’s fisheries (as well as those of many other Asian countries) rely on multi-species resources, all of which interact within the ecosystem. Climate change, habitat degradation, and overfishing leave fisheries vulnerable to sudden declines or unexpected shifts in population dynamics. There is a pressing need for a more holistic management approach that examines how fishing, food webs, habitat conditions, and environmental changes influence fished species. This study documents the application of EBFM in the grouper–snapper fishery of Saleh Bay, Sumbawa Island, eastern Indonesia. The goal is to apply the recently developed Lenfest tools for EBFM to better align Indonesian fisheries with the principles of EBFM by integrating indicators of ecosystem structure and function into the management of small-scale fisheries in Saleh Bay, Indonesia. Key challenges included the diversity of demersal fish stocks (over 80 species recorded in landings and 12 indicator species for management) and fishing methods (8 fishing gears and three main ones for serranids (grouper) and lutjanids (snapper)), limited ecological and fisheries data, and difficulties in balancing complex ecosystem models. Ecopath with Ecosim (EwE) is used to develop the model, which provides tools to develop a flexible, customized, and multi-species fisheries management approach for Saleh Bay that aligns with EBFM.
☕ 10:30–11:00 – Morning Coffee Break
Session 2: Forces, Fluxes, and Exchange at the Land–Sea Interface
This session addresses the physical and biogeochemical linkages between terrestrial and marine systems in tropical coastal zones. It explores how sediment, freshwater, nutrient, and pollutant fluxes shape nearshore oceanography and coastal state and exchange, and how these dynamics are influenced by anthropogenic alterations such as land-use change, deforestation, and coastal development. It emphasises empirical approaches, including observational networks and remote sensing, and their integration into regional and coupled process modelling frameworks. A central aim is to assess the representation of coastal–terrestrial coupling in existing physical–biogeochemical models and to identify strategies for better capturing these fluxes and exchanges across scales and data regimes. Guiding question: How do land–sea and air–sea exchanges shape tropical coasts, and which improvements at these interfaces would most reduce uncertainties from coastal to basin scales?
Chair: Joke Lübbecke (University of Bremen, Germany)
11:00–11:30 – Keynote: Moninya Roughan (UNSW, Australia)
Measuring, Monitoring, and Modelling the East Australian Current System: Closing Observational Gaps and Reducing Uncertainty at the Coastal–Shelf–Bluewater Interface
Knowledge of the three-dimensional structure and variability of the (tropical) coastal – shelf seas is critical for understanding ocean hydrodynamics and circulation, ocean heat uptake and sea level rise (with climate change) as well as for quantification and detection of marine extremes; all of which have significant ecological impacts on the abundance and distribution of marine life, with far-reaching socio-economic consequences.
However, while satellite technology offers near-global coverage of some variables (e.g. sea surface temperature, salinity, ocean colour and sea surface height), and Argo and XBT programs provide sparse subsurface observations, substantial gaps remain, particularly in coastal regions where fisheries are most productive and where humans interact most heavily with the coastal ocean. Additionally, accurate submesoscale representation in ocean models remains a challenge due to rapidly evolving flow and the lack of observations at suitable scales in highly dynamic coastal oceans. Yet, ocean state estimates that represent mesoscale and submesoscale dynamics are crucial for both operational ocean forecasting and climate projections.
Here, I will demonstrate some of the recent efforts in the East Australian Current System to measure, monitor, and model the ocean across a range of time and space scales in an effort to reduce uncertainty at the coastal – shelf – bluewater interface. These initiatives include long-term, sustained, research-quality, ocean monitoring using moorings, HF radar, hydrographic sampling and ocean gliders, as well as a novel crowd-sourced citizen science initiative for real-time operational data delivery. These data are integrated into a data-assimilating ocean model, along with new inputs such as data from the high resolution SWOT satellite, to improve state estimates. We show enhanced representation of ocean processes across scales, essential for improved ocean forecasts and projections, and for reducing uncertainty. Together, these initiatives provide a comprehensive view of an oceanic region undergoing rapid environmental change and are a valuable resource for ocean managers.
11:30–11:45 – Lívia Sancho (Universidade Federal do Rio de Janeiro, Brazil)
From Global Oceans to Regional Extremes: Towards Better Earth System Models
Earth System Models (ESMs) still struggle to represent regional and coastal processes, as their coarse resolution limits the simulation of land–sea exchanges and hydrological extremes. These shortcomings hinder our ability to capture freshwater, sediment, and nutrient fluxes and contribute to large uncertainties in future projections. A range of approaches – such as artificial intelligence, downscaling, and statistical frameworks based on teleconnections – can help bridge this gap. In this talk, I present our recent work on multi-ocean teleconnections and synoptic drivers, including atmospheric blocking events and the South Atlantic Convergence Zone, and their influence on droughts, floods, and heatwaves in South America. By quantifying these links, we propose methodologies that can be integrated into ESMs to improve the representation of regional processes. This multiscale perspective offers a pathway to reduce uncertainties from regional to basin scales.
11:45–12:00 – Kirsten Thonicke, Sabine Mathesius (PIK, Germany), Georg Feulner
Modelling Land-Ocean linkages in Earth System Models, a roadmap to consider coastal ecosystems
Large rivers are a substantial source of freshwater, sediments, nutrients and carbon that influence coastal ecosystems and their biodiversity. They also contribute substantially to marine biogeochemical cycles and coastal deoxygenation. Modelling approaches exist to quantify carbon export to and biogeochemical modification in large river systems, such as the Amazon river (Langerwisch et al. ESD 2016). Embedding such approaches in the hydrological modules and river routing schemes that run inside Dynamic Global Vegetation Models such as LPJmL (Schaphoff et al. 2018) allows to quantify changes in vegetation and cycling of terrestrial carbon and nitrogen under changing environmental conditions, including climate and large-scale deforestation. Such a process-based approach becomes very important when studying land-ocean linkages inside Earth System Models. The LPJmL DGVM is coupled to the Potsdam Earth Model (POEM, Drueke et al. GMD 2021) and provides the ideal modelling platform to study the described effects and changes. However, the modulation of biogeochemical processes in coastal ecosystems is largely missing from such Earth System Models. We provide a model concept on how such analyses can be conducted in Earth System Models, based on coupling land and ocean through a coastal box model that simulates conditions for coastal ecosystems at a finer spatial resolution than captured by the ocean model component.
12:00–12:15 – Sabine Mathesius (PIK, Germany)
Land-Ocean Coupling in POEM: Exploring new ways to simulate climate impacts on coastal ecosystems in an Earth System Model
Coastal marine ecosystems play a key role in global carbon sequestration, but many are increasingly degraded by climate change and other anthropogenic stressors, reducing their capacity for carbon uptake and storage. The Earth system model POEM (Drüke et al. 2021) has been applied to simulate global impacts of rising atmospheric CO₂ (Drüke et al. 2024), but rarely to assess marine ecosystem impacts. We aim to further develop POEM to investigate climate-change effects on the marine biosphere, including coastal ecosystems such as mangroves, seagrass meadows, and kelp forests. Within the Planetary Boundaries framework (Richardson et al. 2023), coastal ecosystems are expected to gain increasing relevance as additional marine processes will likely be incorporated, possibly including biological carbon sequestration (in open-ocean and coastal systems), ocean deoxygenation, and the deterioration of the marine biosphere. Building on POEM’s current marine biogeochemical module (BLINGv2, Dunne et al. 2020), we consider developing a coastal box model that could resolve coastal biological processes, carbon sequestration, and deoxygenation. This box model would account for riverine nutrient and freshwater inflow as well as exchange with open-ocean waters, and it would resolve key biogeochemical variables such as net primary production (NPP), remineralization, phosphorus and nitrogen concentrations, detritus, and burial of organic matter. Marine plant functional types could be implemented and parameterized to represent ecosystems, for example mangroves and kelp. Such an extension of POEM would enable us to better quantify the role of coastal ecosystems in the Earth system, to simulate their future under climate change, and to investigate potential marine planetary boundaries.
References:
Drüke, M., Lucht, W., von Bloh, W., Petri, S., Sakschewski, B., Tobian, A., Loriani, S., Schaphoff, S., Feulner, G., & Thonicke, K. (2024). The long-term impact of transgressing planetary boundaries on biophysical atmosphere–land interactions. Earth System Dynamics, 15, 467–483. https://doi.org/10.5194/esd-15-467-2024
Drüke, M., von Bloh, W., Petri, S., Sakschewski, B., Schaphoff, S., Forkel, M., Huiskamp, W., Feulner, G., & Thonicke, K. (2021). CM2Mc-LPJmL v1.0: Biophysical coupling of a process-based dynamic vegetation model with managed land to a general circulation model. Geoscientific Model Development, 14, 4117–4141. https://doi.org/10.5194/gmd-14-4117-2021
Dunne, J. P., Bociu, I., Bronselaer, B., Guo, H., John, J. G., Krasting, J. P., et al. (2020). Simple global ocean biogeochemistry with Light, Iron, Nutrients and Gas version 2 (BLINGv2): Model description and simulation characteristics in GFDL’s CM4.0. Journal of Advances in Modeling Earth Systems, 12, e2019MS002008. https://doi.org/10.1029/2019MS002008
Richardson, K., Steffen, W., Lucht, W., Bendtsen, J., Cornell, S. E., Donges, J. F., & Rockström, J. (2023). Earth beyond six of nine planetary boundaries. Science Advances, 9(37), eadh2458. https://doi.org/10.1126/sciadv.adh2458
🍽 12:15–13:30 – Lunch Break (lunch provided on site)
13:30–13:45 – Marie-Christin Wimmler (TU Dresden, Germany), Ronny Peters, Guanzhen Liu, Uta Berger
Advancing Ecological Modeling with pyMANGA: Modularity and Reusability for Robust and Reproducible Research
Individual-based vegetation models are essential for understanding and predicting ecosystem responses to environmental change. While these models rely on well-established processes—such as vegetation establishment, growth, and mortality—models of mangroves and other coastal vegetation are often developed from scratch, despite including similar processes. We present pyMANGA, an open-source, modular platform that streamlines model development and enables systematic hypothesis testing. Researchers can combine, modify, and extend concepts of plant growth, competition, and resource dynamics, supporting flexible, reproducible modelling. The platform is particularly suited to the study of ecohydrological interactions, including plant-soil feedback loops in tropical coastal ecosystems. Defined interfaces make it straightforward to compare models of varying complexity, while open access, version control, and automated benchmarking ensure transparency and collaboration. pyMANGA provides opportunities to link vegetation dynamics with observational networks, remote sensing, and coupled physical–biogeochemical models in the future, supporting improved representation of coastal–terrestrial coupling.
13:45–14:00 – Andrés Fernando Osorio Arias (UNAL, Colombia)
Multiscale numerical approaches for evaluating the protective role of coral reefs and mangrove forests
Tropical coastal ecosystems like coral reefs and mangrove forests protect shorelines by reducing flooding, erosion, and wave damage. However, human pressures and climate change threaten their survival, making it vital to quantify their protective role. Numerical modeling offers powerful tools for this purpose. At large scales, process-based models such as XBeach and Delft3D simulate nearshore hydrodynamics, sediment transport, and wave energy dissipation. For example, XBeach has shown how coral reefs reduce flooding by dissipating waves during storms, while Delft3D represents mangroves with vegetation modules that incorporate drag from roots and trunks to capture their wave attenuation capacity. At finer scales, Computational Fluid Dynamics (CFD) models like OpenFOAM analyze fluid–structure interactions. In corals, CFD reveals how colony geometry affects drag, inertia, and turbulence, while for mangroves it resolves root effects on flow and sediment stability. Together, these approaches link ecosystem structure with coastal processes, supporting conservation, management, and adaptation strategies.
14:00–14:15 – Sinikka Lennartz (University of Oldenburg, Germany)
Bridging Scales in Coastal Biogeochemistry from Microbes to Climate
Coastal areas are dynamic hotspots for biogeochemical processes but face increasing anthropogenic pressures from nutrient inputs, pollution, and intensive fishing. Numerical models are essential tools for projecting ecosystem responses, yet they often struggle to bridge critical scales, i.e. from microbial and molecular processes that underpin carbon storage and food web dynamics, to regional impacts of human activities and global climate feedbacks. In this talk, I will present two topical examples that demonstrate approaches to address this issue of scale transitioning in numerical, spatially resolved models. The first example examines the production and emission of climate-relevant trace gases, in particular photochemically produced compounds like carbonyl sulfide. I will highlight how parameterizations based on high-resolution field data can enhance our understanding, with a focus on tropical regions. The second example provides a system-level view of the marine carbon cycle, emphasizing dissolved organic carbon (DOC), a key carbon pool historically overlooked in management strategies. Here, I apply the concept of emergent properties, that is, features of the system that arise only at larger scales. Based on this principle, microbial-scale processes can be scaled up to basin-level patterns using an integrated approach that combines theory, network science, and biogeochemistry. Together, these examples underline key research directions relevant to the TropECs project, particularly the connections between coastal biogeochemistry and the climate system. They also showcase generalizable strategies for advancing coastal ecosystem modeling, in particular scale-aware parameterizations and leveraging emergent properties.
14:15–14:30 – Siny Ndoye (Université Amadou Mahtar Mbow, Senegal)
Physical Modelling of Southern Canary Upwelling System: results, applications, perspectives and needs in terms of in situ data and future perspectives
The dynamics and circulation in the Southern Canary Upwelling System (SCUS) have been investigated for over 10 years with regional CROCO simulations using a grid nest focusing on the Senegal coastal ocean (Δx ≈ 2 km). Hydrographic measurements during UPSEN2-ECOAO survey (4-week intensive field campaign), satellite images datasets (SST and SSH), data from SOLAB low-cost field surveys and Melax observatory buoy are used to evaluate the model skills. Our studies have shed light on the climatological functioning of the senegalese upwelling, offered new perspectives on the connections between the SSUS physics and its ecosystems, and provided insight into the future consequences of climate change on the senegalese coastal ocean. Further model improvements including the operational delivery of short-term forecast would require enhanced in situ data collection. Low-cost field surveys and mooring deployment strategies based on partnerships with artisanal fishermen can potentially help remedy data scarcity for the benefit of model developments and more generally monitoring of the Senegalese marine environment.
14:30–14:45 – Joke Lübbecke (University of Bremen, Germany)
Importance of Large-Scale Climate Modes for Eastern Tropical Atlantic Coastal Conditions
Ocean mean state and variability in tropical-subtropical coastal regions are governed by both local conditions but are also connected to large scale climate modes. This presentation will focus on the role of remote drivers for sea surface temperature (SST) variations in the Mauritanian upwelling and the Angola-Benguela region. SST variations in the Northeastern Tropical Atlantic Upwelling region are related to local wind stress variability that is partly affected by teleconnections from the El Niño – Southern Oscillation in the Pacific. Recent findings also point to a role of thermocline depth variations driven from the equatorial Atlantic. As for the Angola Benguela area, the link to the Atlantic Niño via the propagation of equatorial and coastal trapped waves is well established. A newly discovered link also exists to the Indian Ocean Dipole via the impact on precipitation over the Congo basin and subsequent river runoff.
☕ 14:45–15:15 – Afternoon Coffee Break