The North Sea is changing rapidly, driven by modifications in human activities and impacts of climate change. The reduction of nutrient loads from river discharges and the rising water temperatures act in synergy resulting in modifications on the phenology of marine organisms. Phenological changes have been described for several zooplankton species, but the full extension of their response has been only partially assessed, often ignoring the less abundant but ecologically and/or economically important species. This is particularly true for meroplankton organisms, for which the asynchrony between seasonal cycles of these larvae and their food might ultimately affect the recruitment of the adult benthic populations. Here we used a 46-years time series of meroplankton species (decapod larvae and gelatinous zooplankton), monitored at Helgoland Roads, to describe their long-term changes in phenology associated with modifications in the ecosystem.  We used a combination of linear and non-linear statistical models to uncover (a)synchronous changes in the phenology of species and their environment, its drivers, and what impact they might have on the ecosystem. The results highlight that changes in phenology differed depending on the taxa, stressing the importance of considering species-specific ecology to understand interspecific relationships. This might have important implications for the benthic-pelagic coupling of meroplankton taxa, regulating the recruitment and, therefore, the composition of benthic communities, with possible significant ecological and socioeconomic effects.

Primary Presenter: Raquel Marques, Senckenberg am Meer (raquel.marques@senkenberg.de)

Authors:

Raquel Marques, Senckenberg am Meer, DZMB  (raquel.marques@senkenberg.de)

Saskia Otto, Institute of Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg  (saskia.otto@uni-hamburg.de)

Maarten Boersma, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Shelf Sea System Ecology  (maarten.boersma@awi.de)

Karen Wiltshire, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Shelf Sea System Ecology  (karen.wiltshire@awi.de)

Jasmin Renz, Senckenberg am Meer, DZMB  (jasmin.renz@senckenberg.de)