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The microbiome of the habitat‐forming brown alga Fucus vesiculosus (Phaeophyceae) has similar cross‐Atlantic structure that reflects past and present drivers 1

Publication . Capistrant‐Fossa, Kyle A.; Morrison, Hilary G.; Engelen, Aschwin; Quigley, Charlotte T.C.; Morozov, Aleksey; Serrao, Ester; Brodie, Juliet; Gachon, Claire M.M.; Badis, Yacine; Johnson, Ladd E.; Hoarau, Galice; Abreu, Maria Helena; Tester, Patricia A.; Stearns, Leigh A.; Brawley, Susan H.

Latitudinal diversity gradients have provided many insights into species differentiation and community processes. In the well-studied intertidal zone, however, little is known about latitudinal diversity in microbiomes associated with habitat-forming hosts. We investigated microbiomes of Fucus vesiculosus because of deep understanding of this model system and its latitudinally large, cross-Atlantic range. Given multiple effects of photoperiod, we predicted that cross-Atlantic microbiomes of the Fucus microbiome would be similar at similar latitudes and correlate with environmental factors. We found that community structure and individual amplicon sequencing variants (ASVs) showed distinctive latitudinal distributions, but alpha diversity did not. Latitudinal differentiation was mostly driven by ASVs that were more abundant in cold temperate to subarctic (e.g., Granulosicoccus_t3260, Burkholderia/Caballeronia/Paraburkholderia_t8371) or warm temperate (Pleurocapsa_t10392) latitudes. Their latitudinal distributions correlated with different humidity, tidal heights, and air/sea temperatures, but rarely with irradiance or photoperiod. Many ASVs in potentially symbiotic genera displayed novel phylogenetic biodiversity with differential distributions among tissues and regions, including closely related ASVs with differing north-south distributions that correlated with Fucus phylogeography. An apparent southern range contraction of F. vesiculosus in the NW Atlantic on the North Carolina coast mimics that recently observed in the NE Atlantic. We suggest cross-Atlantic microbial structure of F. vesiculosus is related to a combination of past (glacial-cycle) and contemporary environmental drivers.

2021Journal article

Restricted access

Contrasting drivers and trends of ocean acidification in the subarctic Atlantic

Publication . Pérez, Fiz F.; Olafsson, Jon; Ólafsdóttir, Solveig R.; Fontela, Marcos; Takahashi, Taro

The processes of warming, anthropogenic CO2 (Canth) accumulation, decreasing pHT (increasing [H+]T; concentration in total scale) and calcium carbonate saturation in the subarctic zone of the North Atlantic are unequivocal in the time-series measurements of the Iceland (IS-TS, 1985–2003) and Irminger Sea (IRM-TS, 1983–2013) stations. Both stations show high rates of Canth accumulation with diferent rates of warming, salinifcation and stratifcation linked to regional circulation and dynamics. At the IS-TS, advected and stratifed waters of Arctic origin drive a strong increase in [H+]T, in the surface layer, which is nearly halved in the deep layer (44.7± 3.6 and 25.5 ± 1.0 pmol kg−1 yr−1, respectively). In contrast, the weak stratifcation at the IRM-TS allows warming, salinifcation and Canth uptake to reach the deep layer. The acidifcation trends are even stronger in the deep layer than in the surface layer (44.2± 1.0 pmol kg−1 yr−1 and 32.6 ± 3.4 pmol kg−1 yr−1 of [H+]T, respectively). The driver analysis detects that warming contributes up to 50% to the increase in [H+]T at the IRM-TS but has a small positive efect on calcium carbonate saturation. The Canth increase is the main driver of the observed acidifcation, but it is partially dampened by the northward advection of water with a relatively low natural CO2 content.

2021-07Journal article

Open access