Change search
ReferencesLink to record
Permanent link

Direct link
Light, nutrients and grazing interact to determine stream diatom community composition and functional group structure
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
Show others and affiliations
2011 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 56, no 2, 264-278 p.Article in journal (Refereed) Published
Abstract [en]

P>1. Benthic algal communities are shaped by the availability of nutrients and light and by herbivore consumption. Many studies have examined how one of these factors affects algal communities, but studies simultaneously addressing all three are rare. 2. We investigated the effects of nutrients, light and a herbivore (the snail Potamopyrgus antipodarum) on benthic stream algae in a fully factorial experiment in 128 circular streamside channels. Four nutrient levels (none added to highly enriched), four snail grazing pressures (no snails to 777 individuals m-2) and two light levels (ambient and 65% reduced) were applied. Colonising algae were dominated by diatoms (Bacillariophyta), which were determined to species using acid-cleaned samples and assigned to functional groups according to their physiognomic growth form. 3. Diatom community structure changed considerably in response to our manipulations. Light had the strongest influence (as indicated by manova effect size), whereas nutrients had an intermediate effect and grazing was fairly weak. Relative abundances of six common diatom taxa decreased under reduced light, whereas five others became more prevalent. Eight taxa benefitted from nutrient enrichment, while three became rarer. Grazing affected the relative density of only one common taxon, which increased at higher grazing pressure. 4. Diatom functional groups also responded strongly. 'Low profile' taxa dominated at low resource levels (nutrients and especially light), whereas 'high profile' and 'motile' taxa became markedly more prevalent at higher resource levels. 5. Two-way interactions between experimental factors were quite common. For example, Planothidium lanceolatum and Rossithidium petersenii responded more strongly to nutrient enrichment at reduced than at ambient light, whereas Cocconeis placentula responded more strongly at ambient light. For diatom functional groups, the benefit of nutrient enrichment for 'motile' diatoms was greater at ambient than at reduced light. 6. Our results imply that multifactor experiments are required to determine the main forces driving the composition of benthic algal communities. Further, our findings highlight the considerable potential of using functional algal groups as indicators of changing environmental conditions to complement the traditional taxonomic approach.

Place, publisher, year, edition, pages
Wiley , 2011. Vol. 56, no 2, 264-278 p.
Keyword [en]
benthic algae, diatom physiognomic groups, herbivory, periphyton, resource availability
URN: urn:nbn:se:umu:diva-44166DOI: 10.1111/j.1365-2427.2010.02492.xISI: 000285999100005OAI: diva2:418827
Available from: 2011-05-24 Created: 2011-05-24 Last updated: 2011-06-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Liess, Antonia
By organisation
Department of Ecology and Environmental Sciences
In the same journal
Freshwater Biology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 112 hits
ReferencesLink to record
Permanent link

Direct link