Human activities in the ocean often interact and overlap in space and time. As a result, their impact on the ecosystem can be synergistic, where their combined effect is greater than the sum of their individual effects. As part of the MGF-Nordsee project, we investigated the occurrence of six different human activities inside and outside the German EEZ Natura 2000 sites using EMODnet open source data. We found that a large proportion of the activities still take place inside the MPAs, with an even higher proportion of cables and pipelines inside the MPAs than outside.

We use DNA sequencing to characterize microbial communities from the North Sea and utilize  spatial models to understand how microbiota vary taxonomically and functionally throughout space and time. For this, we have established a monitoring program to collect samples across the German North Sea. Since 2019 over 350 stations were repeatedly sampled. This large dataset is preserved and maintained at the ICBM and will grow over the coming years.

Preliminary results suggest that sediment microbiota vary in response to sediment characteristics, temperature and organic content but also to bottom trawling activity and natural bottom disturbance.

The benthic fish and invertebrate communities were studied in two marine protected areas of the German North Sea using baited underwater video stations (BRUVs). In contrast to the traditional biodiversity monitoring using trawling, BRUVs are a low-impact method to describe species communities. In addition, the comparison of the two methods shows that they record different species, but also overlap. Therefore, a complementary combination of both methods provides the most comprehensive results on the status of marine protected areas. After the exclusion of bottom-contact fisheries, an adapted, non-invasive monitoring plan can be developed based on these studies.

Large stones are rare in the North Sea, but form stone reefs in some places. These provide a special habitat for sessile organisms such as soft corals and sea anemones. Since conventional survey methods are unsuitable for these reefs, video transects were recorded by research divers. The recordings allow an investigation of the species that are present and how they are influenced by factors such as fishing, depth, current and sediment composition.

One Method to analyze benthic communities are Autonomous Reef Monitoring Structures (ARMS). These standardized 3D structures mimic the complex structure of sea bottom habitats (e.g. reefs). The stacked PVC plates offer an attachment substrate for larvae, incrusting invertebrates and hiding spaces for small animals. We deploy the ARMS while diving and attach them with steel rods to the seafloor next to reef structures to evaluate the response of cryptic, often overlooked reef communities  to the different management practices (e.g differences in fishing pressure). In 2021, we deployed 49 ARMS at 10 different stations at the Sylt Outer Reef and Borkum Reef Ground. We will fetch the first ARMS in June 2022 from the seabed and investigate which organisms settled on the individual PVC plates.