The role of the picoeukaryote Aureococcus anophagefferens in cycling of marine high molecular weight dissolved organic nitrogen.

Berg, Gry Mine, Repeta, D. L. and LaRoche, Julie (2003) The role of the picoeukaryote Aureococcus anophagefferens in cycling of marine high molecular weight dissolved organic nitrogen. Limnology and Oceanography, 48 (5). pp. 1825-1830. DOI 10.4319/lo.2003.48.5.1825.

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Abstract

Environmental evidence suggests that Aureococcus anophagefferens (Pelagophyceae), a eukaryotic picoplankton that blooms in coastal seawaters, can outcompete other organisms because of its ability to use abundant dissolved organic nitrogen (DON). To test this hypothesis, we isolated A. anophagefferens in axenic culture and monitored its growth on high-molecular weight (HMW) DON collected from sediment pore waters, a putative source for DON in bays where blooms occur. HMW DON originating from pore water had a substantially higher protein content than surface seawater DON. We found that A. anophagefferens could deplete 25-36% of the available nitrogen in cultures with HMW DON as the sole source of nitrogen and that this corresponded well with the protein fraction in pore-water HMW DON. High rates of cell surface peptide hydrolysis and no detectable N-acetyl polysaccharide hydrolysis, together with the high percentage of hydrolyzable amino acids compared to hydrolyzable aminosugars present in the HMW DON, pointed to the protein fraction as the more likely source of nitrogen used for growth. Whether or not nitrogen scavenging from protein is a common mechanism in phytoplankton is at present unknown but needs to be investigated

Document Type: Article
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BI Biological Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.4319/lo.2003.48.5.1825
ISSN: 0024-3590
Date Deposited: 18 Feb 2008 17:26
Last Modified: 25 Jun 2018 13:51
URI: http://oceanrep.geomar.de/id/eprint/6876

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