WP 2.1 Primary production
Bentho-pelagic coupling is defined as the exchange of energy and nutrients between benthic and pelagic habitats. This exchange plays an important role in aquatic ecosystems and is crucial for nutrient cycling and energy transfer in food webs. It is expected that the exclusion of mobile bottom-contact fishing will have a positive impact on the benthic macrofauna and thus intensify the bentho-pelagic coupling. Accordingly, we will investigate the structure and functioning of bentho-pelagic food webs before and after the implementation of fishing measures. We will analyze abiotic factors of seawater; phytoplankton, microzooplankton, mesozooplankton biomass and community composition; stoichiometry and stable isotopes of different size fractions and of the most common benthic suspension feeders. Additionally, samples of benthic diatoms will be taken in the sediments. Due to the depth and predominant sediment characteristics in the Natura 2000 areas, the formation of a distinct microphytobenthos biofilm is unlikely. Changes of the microphytobenthos community in the course of the MPAs development are nevertheless possible and will be included in the status description in order to follow later developments. In parallel to these analyses, incubation experiments will be performed to quantify the feeding rates of the most abundant filter feeders. Thus, the actual state of the bentho-pelagic nutrient budget and the trophic connections between plankton and benthic filter feeders will be determined.