Net Production and Consumption of Fluorescent Colored Dissolved Organic Matter by Natural Bacterial Assemblages Growing on Marine Phytoplankton Exudates
- 1 November 2011
- journal article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 77 (21), 7490-7498
- https://doi.org/10.1128/aem.00200-11
Abstract
An understanding of the distribution of colored dissolved organic matter (CDOM) in the oceans and its role in the global carbon cycle requires a better knowledge of the colored materials produced and consumed by marine phytoplankton and bacteria. In this work, we examined the net uptake and release of CDOM by a natural bacterial community growing on DOM derived from four phytoplankton species cultured under axenic conditions. Fluorescent humic-like substances exuded by phytoplankton (excitation/emission [Ex/Em] wavelength, 310 nm/392 nm; Coble's peak M) were utilized by bacteria in different proportions depending on the phytoplankton species of origin. Furthermore, bacteria produced humic-like substances that fluoresce at an Ex/Em wavelength of 340 nm/440 nm (Coble's peak C). Differences were also observed in the Ex/Em wavelengths of the protein-like materials (Coble's peak T) produced by phytoplankton and bacteria. The induced fluorescent emission of CDOM produced by prokaryotes was an order of magnitude higher than that of CDOM produced by eukaryotes. We have also examined the final compositions of the bacterial communities growing on the exudates, which differed markedly depending on the phytoplankton species of origin. Alteromonas and Roseobacter were dominant during all the incubations on Chaetoceros sp. and Prorocentrum minimum exudates, respectively. Alteromonas was the dominant group growing on Skeletonema costatum exudates during the exponential growth phase, but it was replaced by Roseobacter afterwards. On Micromonas pusilla exudates, Roseobacter was replaced by Bacteroidetes after the exponential growth phase. Our work shows that fluorescence excitation-emission matrices of CDOM can be a helpful tool for the identification of microbial sources of DOM in the marine environment, but further studies are necessary to explore the association of particular bacterial groups with specific fluorophores.Keywords
This publication has 56 references indexed in Scilit:
- Biogeneration of chromophoric dissolved organic matter by bacteria and krill in the Southern OceanLimnology and Oceanography, 2009
- Physiological Structure and Single‐Cell Activity in Marine BacterioplanktonPublished by Wiley ,2008
- Bacterial and Archaeal Community Structure and its PatternsPublished by Wiley ,2008
- Solar ultraviolet radiation-induced DNA damage in aquatic organisms: potential environmental impactMutation Research - Reviews in Mutation Research, 2005
- Global distribution and dynamics of colored dissolved and detrital organic materialsJournal of Geophysical Research: Oceans, 2002
- Genetic diversity of ‘satellite’ bacteria present in cultures of marine diatomsFEMS Microbiology Ecology, 2002
- Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communitiesScientia Marina, 2000
- Distribution and optical properties of CDOM in the Arabian Sea during the 1995 Southwest MonsoonDeep Sea Research Part II: Topical Studies in Oceanography, 1998
- Characterization of marine and terrestrial DOM in seawater using excitation-emission matrix spectroscopyMarine Chemistry, 1996
- Use of dissolved combined and free amino acids by planktonic bacteria in Lake ConstanceLimnology and Oceanography, 1993