Sunlight Effects on the Osmotrophic Uptake of DMSP-Sulfur and Leucine by Polar Phytoplankton

Author(s)
Clara Ruiz-González, Martí Galí, Eva Sintes Elvelin, Gerhard J. Herndl, Josep M. Gasol, Rafel Simó
Abstract

Even though the uptake and assimilation of organic compounds by phytoplankton has been long recognized, very little is still known about its potential ecological role in natural marine communities and whether it varies depending on the light regimes the algae experience. We combined measurements of size-fractionated assimilation of trace additions of H-3-leucine and S-35-dimethylsulfoniopropionate (DMSP) with microautoradiography to assess the extent and relevance of osmoheterotrophy in summer phytoplankton assemblages from Arctic and Antarctic waters, and the role of solar radiation on it was further investigated by exposing samples to different radiation spectra. Significant assimilation of both substrates occurred in the size fraction containing most phytoplankton (>5 mu m), sunlight exposure generally increasing S-35-DMSP-sulfur assimilation and decreasing H-3-leucine assimilation. Microautoradiography revealed that the capacity to take up both organic substrates seemed widespread among different polar algal phyla, particularly in pennate and centric diatoms, and photosynthetic dinoflagellates. Image analysis of the microautoradiograms showed for the first time interspecific variability in the uptakes of S-35-DMSP and H-3-leucine by phytoplankton depending on the solar spectrum. Overall, these results suggest that the role of polar phytoplankton in the utilization of labile dissolved organic matter may be significant under certain conditions and further confirm the relevance of solar radiation in regulating heterotrophy in the pelagic ocean.

Organisation(s)
External organisation(s)
Spanish National Research Council (CSIC)
Journal
PLoS ONE
Volume
7
ISSN
1932-6203
DOI
https://doi.org/10.1371/journal.pone.0045545
Publication date
09-2012
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
ASJC Scopus subject areas
General Agricultural and Biological Sciences, General Biochemistry,Genetics and Molecular Biology, General Medicine
Sustainable Development Goals
SDG 14 - Life Below Water
Portal url
https://ucrisportal.univie.ac.at/en/publications/fb67d275-8479-4f76-b751-a4ce4e19cf87