Effects of bottom trawling on linked ecological-biogeochemical processes: regional implications for marine management and climate mitigation

Marine sediments are increasingly recognised as carbon (C) sinks, potentially important to preserve in mitigating climate change, and essential in nutrient (N,P) cycling.

However, bottom trawling, a fishing method that disturbs the seabed and suspends sediment, is widespread in these habitats. The potential for release of greenhouse gases and disruption of nutrient cycling poorly understood.

Spatial heterogeneity (in sedimentary setting, faunal communities) and time since the last trawling event likely affect the net impact on CNP storage and O2 consumption. Little is known about these impacts, despite more than a century of intense trawling.

Our multidisciplinary team will use field experiments and measurements to answer key scientific questions about how trawling impacts turbidity, O2 and CNP cycles, and benthic recovery at different spatial and temporal scales. This will provide essential data for scaling up and modelling the consequences of trawling on a regional scale.

Such data is lacking globally, but is also needed for the specific conditions and ecosystems in Swedish waters, e.g. the unique brackish conditions and low biodiversity of the Baltic Sea and the interaction with environmental factors such as hypoxia and eutrophication. The results will support climate, environment and fisheries management.