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More microbes with warming? Analysis of planktonic time-series in the southern Bay of Biscay continental shelf. Xosé Anxelu G. Morán 1 , Laura Díaz-Pérez 1 , Enrique Nogueira 1 and Antonio Bode 2 1 Instituto Español de Oceanografía (IEO), Xixón, Spain
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More microbes with warming? Analysis of planktonic time-series in the southern Bay of Biscay continental shelf Xosé Anxelu G. Morán1, Laura Díaz-Pérez1, Enrique Nogueira1 and Antonio Bode2 1 Instituto Español de Oceanografía (IEO), Xixón, Spain 2 Instituto Español de Oceanografía (IEO), A Coruña, Spain
Ocean plankton and temperature Richardson and Schoeman (2004) Li et al. (2006) Rodríguez (1994)
~2.0 µm ~1.5 µm ~1.0 µm ~0.7 µm FL3 SSC ~0.5 µm FL1 ~0.4 µm SSC What are microbes? Heterotrophicbacteria Picophytoplankton Large picoeukaryotes Beads Small picoeukaryotes HNA bacteria Synechococcus Vaulot 2004 Prochlorococcus LNA bacteria
Study site Bay of Biscay Approx. monthly samplings since 2002 and 2003 Xixón A Coruña
Seasonalpatterns Structure Abundance Picophytoplankton Cyanobacteria (%) Cells ml-1 Heterotrophic bacteria HNA bacteria (%) Month
Seasonalpatterns Coherent temporal and vertical patterns in the contribution of HNA bacteria (the ones more dependent on phytoplankton) Xixón Depth HNA bacteria (%) Month Morán et al. (2011)
Long-termvariability – Picophytoplankton Abundance Structure Xixón Cyanobacteria (%) Log abundance (cells ml-1) A Coruña Date
Long-termvariability – Heterotrophic bacteria Abundance Structure Xixón HNA cells (%) Log abundance (cells ml-1) A Coruña Date
Long-termvariability – Integratedbiomass Xixón Biomass (mg C m-2) picophytoplankton bacteria
More microbeswithwarming? NW r2 = 0.39, p <0.0001, n=152 & NE Atlantic NW r2 = 0.66, p <0.0001, n=154 & NE Atlantic NW r2 = 0.73, p <0.0001, n=152 & NE Atlantic Morán et al. (2010)
Conclusions Marked seasonal patterns in picoplankton abundance and structure were observed at both sites, more marked in Xixón, presumably linked to lower nutrient load. Heterotrophic bacterial abundance showed contrasting long-term trends, decreasing in A Coruña and increasing in Xixón. Time-series data suggest an association of the smallest components of plankton with ocean warming. Thanks!