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Organic matter availability structures microbial biomass and activity in a Mediterranean stream

1. We compared microbial biomass (bacteria, fungi, algae) and the activity of extracellular enzymes used in the decomposition of organic matter (OM) among different benthic substrata (leaves, coarse and fine substrata) over one hydrological year in a Mediterranean stream. 2. Microbial heterotrophic biomass (bacteria plus fungi) was generally higher than autotrophic biomass (algae), except during short periods of high light availability in the spring and winter. During these periods, sources of OM shifted towards autochthonous sources derived mainly from algae, which was demonstrated by high algal biomass and peptidase activity in benthic communities. 3. Heterotrophic activity peaked in the autumn. Bacterial and fungal biomass increased with the decomposition of cellulose and hemicellulose compounds from leaf material. Later, lignin decomposition was stimulated in fine (sand, gravel) and coarse (rocks, boulders and cobbles) substrata by the accumulation of fine detritus. 4. The Mediterranean summer drought provoked an earlier leaf fall. The resumption of the water flow caused the weathering of riparian soils and subsequently a large increase in dissolved organic carbon and nitrate, which led to growth of bacteria and fungi

This study was funded by the projects CGL2005-06739-C02-01 ⁄02 of the Spanish Science Ministry. Additional funding was provided by the Fundación Banco Bilbao Vizcaya Argentaria (Project GLOBRIO).

© Freshwater Biology, 2009, vol. 54, núm. 10, p. 2025-2036

Elsevier

Author: Artigas Alejo, Joan
Romaní i Cornet, Anna M.
Gaudes, Ainhoa
Muñoz Gràcia, Isabel
Sabater, Sergi
Date: 2009 October 1
Abstract: 1. We compared microbial biomass (bacteria, fungi, algae) and the activity of extracellular enzymes used in the decomposition of organic matter (OM) among different benthic substrata (leaves, coarse and fine substrata) over one hydrological year in a Mediterranean stream. 2. Microbial heterotrophic biomass (bacteria plus fungi) was generally higher than autotrophic biomass (algae), except during short periods of high light availability in the spring and winter. During these periods, sources of OM shifted towards autochthonous sources derived mainly from algae, which was demonstrated by high algal biomass and peptidase activity in benthic communities. 3. Heterotrophic activity peaked in the autumn. Bacterial and fungal biomass increased with the decomposition of cellulose and hemicellulose compounds from leaf material. Later, lignin decomposition was stimulated in fine (sand, gravel) and coarse (rocks, boulders and cobbles) substrata by the accumulation of fine detritus. 4. The Mediterranean summer drought provoked an earlier leaf fall. The resumption of the water flow caused the weathering of riparian soils and subsequently a large increase in dissolved organic carbon and nitrate, which led to growth of bacteria and fungi
This study was funded by the projects CGL2005-06739-C02-01 ⁄02 of the Spanish Science Ministry. Additional funding was provided by the Fundación Banco Bilbao Vizcaya Argentaria (Project GLOBRIO).
Format: application/pdf
ISSN: 0046-5070 (versió paper)
1365-2427 (versió electrònica)
Document access: http://hdl.handle.net/10256/12730
Language: eng
Publisher: Elsevier
Collection: MEC/PN 2005-2008/CGL2005-06739-C02-02
Reproducció digital del document publicat a: http://dx.doi.org/10.1111/j.1365-2427.2008.02140.x
Articles publicats (D-CCAA)
Is part of: © Freshwater Biology, 2009, vol. 54, núm. 10, p. 2025-2036
Rights: Tots els drets reservats
Subject: Enzims extracel·lulars
Extracellular enzymes
Biofilms -- Mediterrània, Regió
Biofilms -- Mediterranean Region
Ecologia fluvial -- Mediterrània, Regió
Stream ecology -- Mediterranean Region
Ecologia microbiana -- Mediterrània, Regió
Microbial ecology -- Mediterranean Region
Title: Organic matter availability structures microbial biomass and activity in a Mediterranean stream
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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