Control of microbenthic communities by grazing and nutrient supply.

Hillebrand, Helmut, Kahlert, M., Haglund, A. L., Berninger, U. G., Nagel, S. and Wickham, S. (2002) Control of microbenthic communities by grazing and nutrient supply. Ecology, 83 (8). pp. 2205-2219. DOI 10.1890/0012-9658(2002)083[2205:COMCBG]2.0.CO;2.

[thumbnail of ecy20028382205.pdf] Text
ecy20028382205.pdf - Published Version
Restricted to Registered users only

Download (945kB) | Contact

Supplementary data:

Abstract

In periphyton communities, autotrophic algae and prokaryotes live in close spatial proximity to heterotrophic components such as bacteria and micro- and meiofauna. In factorial field experiments, we manipulated grazer access and nutrient supply to periphyton communities and measured the effects on algal, ciliate, meiofaunal, and bacterial biomass. We tested whether grazing macrozoobenthos affects all periphytic components (generalist consumption), whether nutrient effects propagate through the community, and whether interactions between the different periphyton groups allow for indirect feedback mechanisms. The experiments were conducted during three different seasons in a meso-eutrophic lake in Sweden (Lake Erken) and at an adjacent coastal marine site (Väddö) of similar productivity, but with contrasting grazer fauna. We found strong direct effects of nutrients and grazing on algae at both sites. Algal biomass increased in fertilized treatments and was significantly reduced when grazers were present. The algae clearly dominated the system quantitatively and were positively correlated to the biomass of ciliates and meiofauna. The effects of grazing and nutrients were more complex for heterotrophs than for algae. Generally, the presence of grazers tended to increase the biomass of bacteria, ciliates, and meiofauna. Thus, macrograzers were not generalist consumers of the entire community, but mainly reduced algae. Furthermore, the results suggested strong indirect effects of grazing, presumably through changes in nutrient supply and algal size structure. Nutrient enrichment had weak and inconsistent effects on bacterial, ciliate, and meiofaunal biomass. There was thus no complete propagation of bottom-up effects through the community, and strong internal feedback mechanisms within the periphyton mediated the effects of macroconsumers and nutrient enrichment.

Document Type: Article
Keywords: algae; bacteria; bottom-up mechanisms; ciliates; grazing; indirect effects; macroinvertebrates; meiofauna; nutrient regeneration; periphyton; protozoa; top-down mechanisms
Refereed: Yes
Open Access Journal?: No
Publisher: Wiley
Date Deposited: 06 Feb 2009 13:52
Last Modified: 17 Feb 2017 11:34
URI: https://oceanrep.geomar.de/id/eprint/7752

Actions (login required)

View Item View Item