Presentation 1: Modelling the Impact of Bottom Trawling on Air-Sea CO₂ Flux in the North Sea
Pooja Tiwari, Helmholtz-Zentrum Hereon, Germany
Abstract: The dynamic drivers of the marine carbon cycle are essential for predicting how human activities shape ocean-atmosphere CO₂ fluxes in a changing climate. Bottom trawling disrupts natural carbon flows through sediment resuspension, but reliable estimates of this effect have proven difficult to compile due to the complexity of the processes involved. We utilize the three-dimensional coupled physical-biological model SCHISM-ECOSMO-CARBON, which includes a carbonate chemistry module, to explain the physical-biogeochemical impacts of bottom trawling on the North Sea's carbon cycle. We examined the impact of bottom trawling for the period 2000-2005 using two model simulations. The first simulation includes only natural resuspension, while the second experiment considers a parametrization for bottom trawling-induced resuspension. We utilized detailed fishing activity data—including vessel position, size, and engine power—alongside estimated resuspension rates for various fishing gear to generate daily forcings for trawling-induced resuspension. Scenario simulations shown that bottom trawling influences particulate organic carbon, dissolved inorganic carbon, and air-sea CO₂ exchange. The results show spatially heterogeneous variability in air-sea flux changes, resulting from changes in remineralization and ecosystem productivity. Our findings provide critical insights into the impact of ongoing bottom trawling on the North Sea carbon distribution.
Keywords: Carbonate, Air-sea flux, North Sea, Bottom trawling, Remineralization
Bio: I am a final-year PhD student researching the impacts of bottom trawling in the North Sea using a high-resolution 3D numerical ocean model. My work focuses on understanding sediment transport caused by trawling activities and its impact on the intersection of marine ecosystem dynamics.
Presentation 2: Bridging the gap: integrating EBSA criteria into cumulative impact assessments for ecosystem-based marine spatial planning
Kars Hüsken, Wageningen Marine Research, Netherlands
Abstract: Marine spatial planning (MSP) balances conservation with sustainable use of marine ecosystems. The Convention on Biological Diversity (CBD) introduced Ecologically or Biologically Significant Marine Areas (EBSAs) to identify key biodiversity areas, but integrating them into MSP remains challenging due to subjective weighting of criteria. Meanwhile, cumulative impact assessments (CIAs) increasingly support ecosystem-based MSP (EB-MSP) and can play a key role integrating conservation frameworks such as EBSAs. This study interprets EBSA criteria to align them with the SCAIRM (Spatial Cumulative Assessment of Impact Risk for Management) parametrisation and provide EBSA-compliant guidance for EB-MSP. Applying this approach in the North Sea, we demonstrate how this CIA quantifies EBSA criteria such as vulnerability based on stressor-receptor interactions, ecosystem resilience, and biodiversity values. Additionally, this approach supports the generation of EBSA-compliant maps, including an MPA-Guide protection level classification of Marine Protected Areas (MPAs) and Other Effective Area-Based Conservation Measures (OECMs). Our findings demonstrate how the application of a CIA avoids the haphazard and often implicitly subjective weighting of EBSA criteria, thus incorporating conservation into EB-MSP decision-making to enhance marine biodiversity protection. By integrating CIAs into EB-MSP, a clear, data-driven framework is established, ensuring that conservation measures support long-term ecosystem resilience and biodiversity conservation.
Keywords: MSP, EBSA, CIA, North Sea, Decision Support System
Bio: I’m a marine ecologist at Wageningen Marine Research, focusing on spatial analyses of human pressures and ecological impacts in the marine environment. With a broad background in ecology, I work on translating complex models into clear insights to support policy and management. In my work, I bring together ecological knowledge, data and tools to support informed decision-making.
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