Publications

Phytoplankton chemotaxonomy within contiguous optical layers across the western North Atlantic Ocean and its relationship to environmental parameters

Faculty Author(s): Vaillancourt, Robert D.
Student Author(s): -
Department: ESCI
Publication: Deep-Sea Research. Part I, Oceanographic Research Papers
Year: 2018
Abstract: To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1016/j.dsr.2018.05.007 Byline: Robert D. Vaillancourt [robert.vaillancourt@millersville.edu] (a,*), Veronica P. Lance [veronica.lance@noaa.gov] (b,c), John F. Marra [jfm7780@brooklyn.cuny.edu] (d,e) Keywords Phytoplankton; Redundancy analysis; CHEMTAX; Community composition; Environmental control; Northwest Atlantic Ocean Highlights * CHEMTAX analysis was done within optical layers to avoid problems related to photo-acclimation. * Haptophyes were the dominant CHEMTAX class. * Eukaryotes had positive correlations to one another, and weak or zero correlations to cyanobacteria. * Eukaryotes strongly associated with colder, fresher waters with high macronutrients. * Salinity correlated negatively to Synechococcus and eukaryotes, and positively to Prochlorococcus. Abstract A CHEMTAX analysis of the phytoplankton community composition is presented for the summertime northwest Atlantic Ocean from the Sargasso Sea to the New England continental shelf. To minimize the confounding influence of light intensity-related changes in internal pigment concentration (photo-acclimation), we compared CHEMTAX community composition within (but not between) five discrete optical depth layers (OL1 -5) arranged vertically throughout and beneath the euphotic zone, and extending horizontally from the oligotrophic to mesotrophic regions. CHEMTAX model results revealed a gradient of increasing proportions of eukaryotes to prokaryotes in the landward direction. The oligotrophic oceanic waters were dominated about equally by Prochlorococcus and haptophytes with Synechococcus and prasinophytes being secondarily important, while the mesotrophic slope and shelf waters were dominated by haptophytes and prasinophytes, with Prochlorococcus undetectable in shelf waters. Redundancy analysis revealed strong and significant niche separations between eukaryotic and prokaryotic phytoplankton, with the cyanobacteria more common in warmer, saltier waters, and eukaryotic species more common in fresher, colder waters. Salinity was the strongest predictor of the phytoplankton community composition in OLs 2 through 5, but in the surface OL1 temperature was the strongest predictor. There were positive significant correlations between salinity and Prochlorococcus, and negative significant correlations between salinity and all eukaryote groups: pelagophytes, chlorophytes, haptophytes, diatoms, prasinophytes, cryptophytes, and dinoflagellates, in most cases the strength of the correlation increased with depth. Other environmental variables, PO.sub.4.sup.3-, NO.sub.3.sup.-+NO.sub.2.sup.-, and vertical density stratification were all weak predictors of phytoplankton community composition. Author Affiliation: (a) Department of Earth Sciences, Millersville University of Pennsylvania, Millersville, PA 17551, United States (b) National Oceanic and Atmospheric Administration, National Environmental Satellite Data and Information Service, Center for Satellite Applications and Research, College Park, MD 20740, United States (c) Global Science and Technology, Inc., Greenbelt, MD 20770, United States (d) Department of Earth and Environmental Sciences, Brooklyn College (CUNY), Brooklyn, NY 11210, United States (e) Earth and Environmental Sciences Program, CUNY Graduate Center, New York, NY 10016, United States * Corresponding author. Article History: Received 17 March 2017; Revised 6 April 2018; Accepted 18 May 2018
Link: Phytoplankton chemotaxonomy within contiguous optical layers across the western North Atlantic Ocean and its relationship to environmental parameters