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Global pressures, specific responses: effects of nutrient enrichment in streams from different biomes


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Title Global pressures, specific responses: effects of nutrient enrichment in streams from different biomes
Title of Series Environmental Research Letters, Volume 8, 2013
Author Artigas, Joan
García-Berthou, Emili
Bauer, Delia E.
Castro, Maria I.
Cochero, Joaquín
Colautti, Darío C.
Cortelezzi, Agustina
Donato, John C.
Elosegi, Arturo
Feijoó, Claudia
Giorgi, Adonis
Gómez, Nora
Leggieri, Leonardo
Muñoz, Isabel
Rodrigues-Capítulo, Alberto
Romaní, Anna M.
Sabater, Sergi
License CC Attribution - NonCommercial - ShareAlike 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license.
DOI 10.5446/39483
Publisher Institute of Physics (IOP)
Release Date 2013
Language English

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Subject Area Physics
Abstract We assessed the effects of nutrient enrichment on three stream ecosystems running through distinct biomes (Mediterranean, Pampean and Andean). We increased the concentrations of N and P in the stream water 1.6–4-fold following a before–after control–impact paired series (BACIPS) design in each stream, and evaluated changes in the biomass of bacteria, primary producers, invertebrates and fish in the enriched (E) versus control (C) reaches after nutrient addition through a predictive-BACIPS approach. The treatment produced variable biomass responses (2–77% of explained variance) among biological communities and streams. The greatest biomass response was observed for algae in the Andean stream (77% of the variance), although fish also showed important biomass responses (about 9–48%). The strongest biomass response to enrichment (77% in all biological compartments) was found in the Andean stream. The magnitude and seasonality of biomass responses to enrichment were highly site specific, often depending on the basal nutrient concentration and on windows of ecological opportunity (periods when environmental constraints other than nutrients do not limit biomass growth). The Pampean stream, with high basal nutrient concentrations, showed a weak response to enrichment (except for invertebrates), whereas the greater responses of Andean stream communities were presumably favored by wider windows of ecological opportunity in comparison to those from the Mediterranean stream. Despite variation among sites, enrichment globally stimulated the algal-based food webs (algae and invertebrate grazers) but not the detritus-based food webs (bacteria and invertebrate shredders). This study shows that nutrient enrichment tends to globally enhance the biomass of stream biological assemblages, but that its magnitude and extent within the food web are complex and are strongly determined by environmental factors and ecosystem structure.
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human activities are resulting in global
environmental change 1 of the most worrying trends is an increasing nutrient
content worldwide you right from
agricultural fertilizers and urban waste water higher nutrient
levels threaten freshwater erectus
systems although the response can depend on climatic and geographic constraints how much this response is
universal research to respond to this
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main biological company and bacteria
algae and invertebrates and face to that
of upstream control switches the
climatic and geographic differences between the sides resulting contrasting windows
of opportunities for the response of organisms to nutrients for
instance temperature changes seasonally
the Mediterranean impact constraints nothing in the end you want on the other hand light
availability in the Mediterranean stream is loud throughout the year except in a
short period in the spring before the leave that during the right area forest as a
consequence the response of to remake
assistance to nutrient enrichment was higher specific the strongest biomass
responses acute in Gandhi's framed as a result of wire windows of opportunity the weakest independently and where the basal nutrient concentrations were already high in the Mediterranean the response was limited to short temporal windows of light availability and the
seasonality of biomass response was also highly specific algae for
instance only responded in areas
bring in the Mediterranean stream whereas in
the end you want responded throughout the year the state variation among
sites enrichment globally
stimulated the algal based food web
but not straight A's based ones the
present study shows that nutrient enrichment tends to globally enhance the by your west of stream geological assemblages but that its magnitude in which within the food web depends on environmental factors on the structure of the existence


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