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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13209

Response of copepod communities to sea warming in three time-series across the North Atlantic and Mediterranean Sea

Ernesto Villarino (,)*, Xabier Irigoien (, ), Fernando Villate (), Arantza Iriarte (), Ibon Uriarte (), Soultana Zervoudaki (), Jacob Carstensen (), Todd D. O'Brien (), Guillem Chust ()

*Corresponding author:

ABSTRACT: The rapid sea warming experienced across the oceans during the last decades has affected distributional patterns of marine planktonic communities. Here, we analyse links between sea warming and changes in copepod community composition over the last three decades (1980-2012). We used zooplankton time-series data which included 79 species of copepods collected at three sites in the eastern North Atlantic (Bay of Biscay and the Kattegat Sea) and the Mediterranean Sea (Gulf of Saronikos). First, using community β-diversity metrics, we analysed temporal patterns of copepod community composition changes over time and its relation to local environmental conditions. Second, to test whether the changes in copepod community composition correspond to community thermal preferences, we used the Community Temperature Index (CTI), and compared CTI interannual changes with local temperature trends. The β-diversity analysis reveals a high temporal turnover in the copepod community composition at the three sites (30-45%), with a significant similarity decrease over time (“decay”) associated with both niche descriptors and demographic stochastic processes. CTI results reveal that both in Kattegat and Saronikos, where the sea warming velocity was strongest amongst sites, copepod community changes are linked to temperature variability, suggesting that the community is tracking their thermal niche over time. Our findings unveil the fundamental role of abiotic factors structuring copepod biodiversity over time and reveals that the local velocity of sea warming and the species thermal thresholds are key to rearranging copepod community composition in coastal ecosystems.