Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency

Abstract
Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous zooplankton is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was <28% of the assimilated carbon. Taken collectively, the incorporation of terrestrial carbon into zooplankton was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton.
Main Authors
Format
Articles Research article
Published
2016
Series
Subjects
Publication in research information system
Publisher
Nature Publishing Group
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-201608153797Käytä tätä linkitykseen.
Review status
Peer reviewed
ISSN
2045-2322
DOI
https://doi.org/10.1038/srep30897
Language
English
Published in
Scientific Reports
Citation
  • Taipale, S. J., Galloway, A. W. E., Aalto, S. L., Kahilainen, K. K., Strandberg, U., & Kankaala, P. (2016). Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency. Scientific Reports, 6, Article 30897. https://doi.org/10.1038/srep30897
License
Open Access
Copyright© the Authors, 2016. This is an open access article published by Nature and distributed under the terms of a Creative Commons License.

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