UV-B effects on microplankton communities in Kongsfjord, Svalbard - A mesocosm experiment

Author(s)
Sten-Ake Wangberg, Kristin I. M. Andreasson, Kim Gustavson, Thomas Reinthaler, Peter Henriksen
Abstract

The effect of ambient ultraviolet radiation on microplankton communities in an Arctic fjord was measured in mesocosms incubated for 9 days at 2 or 5 meters depth. The mesocosms were either shielded from UV-B radiation by Mylar foil or received full radiation. The parameters measured were: microscopic counts of phytoplankton and micro-zooplankton, photosynthetic capacity, the wave length-dependent inhibition of photosynthesis, and bacterial biomass and production. The results showed that UV-B radiation increased the photosynthetic capacity of the community but that the overall biomass of the plankton community was reduced. This indicates that UV-B exposure results in a net impairment of the plankton community in that it reduces the potential to allocate the photosynthetic product into new biomass or that the grazing pressure is higher in the UV-B exposed mesocosms. There were no differences in the wavelength dependence between communities exposed to UV-B versus not, but we observed a significantly lower dependence in communities from 2 m depth compared to those from 5 m, indicating that an acclimation of the photosynthetic apparatus to high radiation also reduces the wavelength dependence. A general effect was an increase in nanoflagellate and choarroflagellate biomass and a decreased in the biomass of ciliates and bacteria. The increase nanoflagellates was significantly larger in mesocosms shielded from UV-B, while choanoflagellates increased more in UV-B exposed mesocosms. (C) 2008 Elsevier B.V. All rights reserved.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
Royal Netherlands Institute for Sea Research, University of Gothenburg, DHI Water & Environm, Aarhus University
Journal
Journal of Experimental Marine Biology and Ecology
Volume
365
Pages
156-163
No. of pages
8
ISSN
0022-0981
DOI
https://doi.org/10.1016/j.jembe.2008.08.010
Publication date
10-2008
Peer reviewed
Yes
Austrian Fields of Science 2012
Marine biology
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/uvb-effects-on-microplankton-communities-in-kongsfjord-svalbard--a-mesocosm-experiment(27e79b5d-46d5-4725-a706-cd973385cda9).html