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Terrestrial support of zooplankton biomass in northern rivers

Author:
  • M. Berggren
  • P. Bengtson
  • A. R.A. Soares
  • J. Karlsson
Publishing year: 2018-11-05
Language: English
Pages: 2479-2492
Publication/Series: Limnology and Oceanography
Volume: 63
Issue: 6
Document type: Journal article
Publisher: ASLO

Abstract english

The contribution of terrestrially derived carbon to micro-crustacean zooplankton biomass (i.e., allochthony) has been previously studied in lakes, reservoirs, and estuaries, but little is known about zooplankton allochthony in rivers. In lacustrine environments, allochthony is regulated by distinct selective feeding behavior of different taxa. However, we hypothesized that restricted possibility for selective grazing in turbulent environments such as rivers would decouple zooplankton from specific microbial and algal food resources, such that their allochthony would mirror the terrestrial contribution to the surrounding bulk particle pool. We tested this idea by analyzing allochthony in 13 widely distributed Swedish rivers, using a dual-isotope mixing model. Zooplankton biomasses were generally low, and allochthony in different micro-crustacean groups (Cladocera, Cyclopoida, Calanoida) varied from 2% to 77%. As predicted, there were no correlations between allochthony and variables indicating the supply of algal and microbial food resources, such as chlorophyll a and bacterial production. Instead, the allochthony was generally similar to the share allochthonous contribution in bulk particulate organic matter, with relationships close to the 1: 1 line. The zooplankton community allochthony was strongly regulated by the ecosystem metabolic balance between production and respiration, which in turn was dependent upon the ratio between total autochthonous organic carbon concentrations and water color. Our study for the first time shows that micro-crustacean allochthony is regulated differently in rivers compared to in lacustrine systems, and points to inefficient support of zooplankton biomass by algal resources in turbulent waters.

Keywords

  • Ecology

Other

Published
  • ISSN: 1939-5590
Per Bengtson
E-mail: per [dot] bengtson [at] biol [dot] lu [dot] se

Researcher

MEMEG

+46 46 222 37 60

E-F212

Sölvegatan 37, Lund

50

Research group

Microbial Ecology

Projects

Doctoral students and postdocs

PhD students, main supervisor

 

PhD students, assistant supervisor

Jian Li

Experimental setup