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Role of nutrient supply in grazer-periphyton interactions: Reciprocal influences of periphyton and grazer nutrient stoichiometry
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
2006 (English)In: Journal of The North American Benthological Society, ISSN 0887-3593, Vol. 25, no 3, 632-642 p.Article in journal (Refereed) Published
Abstract [en]

Grazer-periphyton interactions are shaped, in part, by indirect effects of nutrient regeneration. They are an important model system with which to test predictions of ecological stoichiometry and the Growth Rate Hypothesis. We conducted a laboratory experiment to test how nutrient enrichment and grazer identity interact to regulate the nutrient content and stoichiometry of both periphyton and consumers. We considered a situation in which P concentration in the water column was high, in contrast to previous experiments in which P was the limiting nutrient. We added N and P, alone and in combination, to the water in experimental aquaria that contained periphyton communities on clay tiles and grazers (1 of 3 snail species) or no grazers (ungrazed control). Benthic algae incorporated nutrients in close proportion to their availability in each nutrient treatment. Algal biomass increased significantly with +N+P enrichment, but not with +N or +P enrichment alone. Grazers had no effect on periphyton C:N ratios and positive effects on periphyton C:P and N:P ratios. P content of grazers (% dry mass) increased and C:P and N:P molar ratios of grazers decreased in response to N enrichment of the water. Grazer P content increased in response to N enrichment, probably because of increased grazer growth rates. We hypothesize that the addition of N under N-limiting conditions led to increased P uptake or retention by grazers because of high growth rates and RNA production, consistent with the Growth Rate Hypothesis.

Place, publisher, year, edition, pages
2006. Vol. 25, no 3, 632-642 p.
Keyword [en]
nutrient cycling, benthos, food web, C : N : P stoichiometry, gastropods, Growth Rate Hypothesis
National Category
URN: urn:nbn:se:uu:diva-94625DOI: 10.1899/0887-3593(2006)25[632:RONSIG]2.0.CO;2ISI: 000239769000009OAI: oai:DiVA.org:uu-94625DiVA: diva2:168531
Available from: 2006-05-24 Created: 2006-05-24 Last updated: 2013-09-25Bibliographically approved
In thesis
1. Nutrient Stoichiometry in Benthic Food Webs – Interactions Between Algae, Herbivores and Fish
Open this publication in new window or tab >>Nutrient Stoichiometry in Benthic Food Webs – Interactions Between Algae, Herbivores and Fish
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this thesis was to identify general structuring mechanisms in benthic food webs within the framework of ecological stoichiometry theory. Ecological stoichiometry is defined as the balance of multiple chemical substances in ecological interactions and explicitly considers the combined dynamics of key elements such as carbon (C), nitrogen (N) and phosphorus (P). Ecological stoichiometry theory was developed for pelagic environments, thus it must be tested whether the same mechanisms are applicable to benthic environments.

In this thesis, ecological stoichiometry theory was used as a framework to investigate nutrient pathways in benthic littoral ecosystems. I conducted one invertebrate field sampling and six experiments. In the experiments, factors such as grazing, light, nutrients and fish presence were manipulated.

The results showed that stoichiometric variability in consumers could mostly be explained by taxa. However, there was some stoichiometric variability due to sampling season, site, and nutrient enrichment.

Grazing mostly increased periphyton N and P content, although nutrient recycling effects were dependent on grazer stoichiometry. Grazing changed benthic algal community composition by increasing the proportion of grazing resistant algae species. Additionally, grazing decreased algal diversity, especially under nutrient poor conditions. The manipulation of fish presence revealed that fish affected primary producer biomass and stoichiometry through nutrient recycling.

The manipulation of abiotic factors, such as light and nutrient addition could affect periphyton nutrient content, biomass and benthic algal chlorophyll a content. The separate addition of N or P led to an increase of the added nutrient in the periphyton. Increased light intensities led to a decreased cellular chlorophyll a content and increased C:nutrient ratios.

This thesis arrives at the conclusion that periphyton-grazer-predator interactions in the benthic are bound by stoichiometric constraints. Nutrient recycling by benthic invertebrates and fish are important mechanism in benthic littoral ecosystems.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 44 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 197
Ecology, ecologial stoichiometry, periphyton, grazer, benthos, trophic interactions, nutrient, algae, Ekologi
urn:nbn:se:uu:diva-6933 (URN)91-554-6592-7 (ISBN)
Public defence
2006-09-08, Friessalen, Kärnhuset, EBC, Norbyvägen 18, 752 36 Uppsala, 10:00
Available from: 2006-05-24 Created: 2006-05-24 Last updated: 2011-06-28Bibliographically approved

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