A Gulf Stream frontal eddy harbors a distinct microbiome compared to adjacent waters

PLoS One. 2023 Nov 9;18(11):e0293334. doi: 10.1371/journal.pone.0293334. eCollection 2023.

Abstract

Mesoscale oceanographic features, including eddies, have the potential to alter productivity and other biogeochemical rates in the ocean. Here, we examine the microbiome of a cyclonic, Gulf Stream frontal eddy, with a distinct origin and environmental parameters compared to surrounding waters, in order to better understand the processes dominating microbial community assembly in the dynamic coastal ocean. Our microbiome-based approach identified the eddy as distinct from the surround Gulf Stream waters. The eddy-associated microbial community occupied a larger area than identified by temperature and salinity alone, increasing the predicted extent of eddy-associated biogeochemical processes. While the eddy formed on the continental shelf, after two weeks both environmental parameters and microbiome composition of the eddy were most similar to the Gulf Stream, suggesting the effect of environmental filtering on community assembly or physical mixing with adjacent Gulf Stream waters. In spite of the potential for eddy-driven upwelling to introduce nutrients and stimulate primary production, eddy surface waters exhibit lower chlorophyll a along with a distinct and less even microbial community, compared to the Gulf Stream. At the population level, the eddy microbiome exhibited differences among the cyanobacteria (e.g. lower Trichodesmium and higher Prochlorococcus) and in the heterotrophic alpha Proteobacteria (e.g. lower relative abundances of specific SAR11 phylotypes) versus the Gulf Stream. However, better delineation of the relative roles of processes driving eddy community assembly will likely require following the eddy and surrounding waters since inception. Additionally, sampling throughout the water column could better clarify the contribution of these mesoscale features to primary production and carbon export in the oceans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorophyll A
  • Cyanobacteria*
  • Humans
  • Oceans and Seas
  • Seawater* / chemistry
  • Temperature

Substances

  • Chlorophyll A

Grants and funding

R/V Shearwater ship time was supported by Nicholas School of the Environment and Duke University Marine Lab Donors through a student research grant to PCG. This research was supported by US National Science Foundation grants ([http://www.nsf.gov; ICER: 2033934; DEB: 2224819) to DEH and a National Aeronautics and Space Association (NASA; [http://www.nasa.gov)]www.nasa.gov) Future Investigators in Earth and Space Science and Technology (FINESST) grant (80NSSC19K1366) to PCB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.