The North Sea is a world-leading area in Offshore Wind Farms (OWFs) energy production. The presence of OWF turbines affects the local marine ecosystem structure and its functioning. The turbines provide new artificial hard substrates, rapidly colonized by epifaunal organisms, mainly consisting of suspension-feeding communities dominated by blue mussel (Mytilus edulis), tube-building amphipods (Jassa herdmani), and plumose anemones (Metridium senile). They feed by removing suspended particate matter, zooplankton, and phytoplankton from the water column, and return faecal pellets (FP) to the water column. These FP are thought to play a crucial role in the local organic matter (OM) dynamics and carbon sequestration in the sediment surrounding the turbines. To quantify their importance within the pelagic and benthic OM pools of OWFs ecosystems, it is essential to develop tracers for FP of the dominant species and other contributors (phyto-, zooplankton, and bacteria-degraded OM). We incubated the three species of interest in controlled lab conditions to harvest species-specific FP. We then analyzed the δ¹⁵N signal of the individual AA in these FP, and the other components of the marine OM pool, to develop a Compound-Specific Stable Isotope Analysis of amino acids (CSSIA–AA) fingerprint. Through multivariate techniques, the AAs with the strongest discriminating power between the potential sources are identified. These AAs will subsequently be used in a Bayesian Mixing Model, to finally estimate the proportional contribution of FP to the OM pool of the OWF environment.

Primary Presenter: Esther Cepeda Gamella, Royal Belgium Institute of Natural Sciences (ecepedagamella@naturalsciences.be)

Authors:

Esther Cepeda Gamella, Royal Belgium Institute of Natural Sciences  (ecepedagamella@naturalsciences.be)

Pascal Boeckx, Gent University  (Pascal.Boeckx@UGent.be)

Samuel Bodé, Gent University  (Samuel.Bode@UGent.be)

Ulrike Braeckman, Gent University  (ulrike.braeckman@ugent.be)

Steven Degraer, Royal Belgium Institute of Natural Sciences  (sdegraer@naturalsciences.be)

Tom Moens, Gent University  (Tom.Moens@UGent.be)

Jan Vanaverbeke, Royal Belgian Institute of Natural Sciences  (jvanaverbeke@naturalsciences.be)