MEPS 592:77-95 (2018)  -  DOI: https://doi.org/10.3354/meps12481

Production and consumption of extracellular polymeric substances in an intertidal diatom mat

Tanja C. W. Moerdijk-Poortvliet1,2,*, Olivier Beauchard1,3,4, Lucas J. Stal1,5, Henricus T. S. Boschker1

1NIOZ Royal Institute for Sea Research and Utrecht University, PO Box 140, 4401 AC Yerseke, The Netherlands
2HZ University of Applied Sciences, Chemistry Department, PO Box 364, 4380 AJ Vlissingen, the Netherlands
3Flanders Marine Institute (VLIZ), InnovOcean site, Wandelaarkaai 7, 8400 Oostende, Belgium
4University of Antwerp, Department of Biology, Ecosystem Management Research Group (ECOBE), Universiteitsplein 1, 2610 Antwerpen, Belgium
5University of Amsterdam, Department of Freshwater and Marine Ecology, PO Box 94248, 1090 GE Amsterdam, The Netherlands
*Corresponding author:

ABSTRACT: We investigated seasonal changes in the production of extracellular polymeric substances (EPS) and short-chain organic acids (SCOA) exuded by benthic diatoms, and the use of these exudates as a carbon source by heterotrophic bacteria. An in situ 13C pulse-chase method was used to follow the fate of EPS for 5 consecutive days. These experiments were done at 2 mo intervals for 1 yr. The EPS were recovered from the sediment as 2 operationally defined fractions (i.e. water-extractable and EDTA-extractable EPS). Seasonal differences in EPS production correlated to light intensity and temperature. From February until June the biomass and production of diatoms and bacteria were closely coupled. It was concluded that SCOA were the most important substrates for the bacteria. Sulfate-reducing bacteria (SRB) in particular benefited from SCOA released by diatoms. From August on, the coupling of biomass and production of diatoms and bacteria weakened and was almost lost in December. During the period from August to December, EPS produced by diatoms promoted the growth of other bacterial taxa rather than SRB, and the production of SCOA was low. Thus, it appears that the seasonal variation in exudates produced by diatoms plays an important role in shaping community composition and maintaining the diversity of the associated bacteria.


KEY WORDS: Microphytobenthos · In situ 13C-labeling · Extracellular polymeric substances


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Cite this article as: Moerdijk-Poortvliet TCW, Beauchard O, Stal LJ, Boschker HTS (2018) Production and consumption of extracellular polymeric substances in an intertidal diatom mat. Mar Ecol Prog Ser 592:77-95. https://doi.org/10.3354/meps12481

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