title: Impacts of fish farm pollution on ecosystem structure and function of tropical headwater streams.
abstract: We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics.
authors.affiliation: Graduate Program of Bioengineering, Federal University of São João del-Rei, Praça Dom Helvécio 74, 36301-160 São João del Rei, MG, Brazil.
authors.forename: Rodrigo dos Santos
authors.initials: Rdos S
authors.lastname: Rosa
authors.forename: Anna Carolina Fornero
authors.initials: AC
authors.lastname: Aguiar
authors.forename: Iola Gonçalves
authors.initials: IG
authors.lastname: Boëchat
authors.forename: Björn
authors.initials: B
authors.lastname: Gücker
mesh_terms: D000818:Animals; D017756:Aquaculture; D059001:Aquatic Organisms / Q000145:classification / Q000254:growth & development; D044822:Biodiversity; D001938:Brazil; D017753:Ecosystem; D004784:Environmental Monitoring; D005399:Fishes; D007448:Invertebrates / Q000145:classification / Q000254:growth & development; D045483:Rivers / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution / Q000706:statistics & numerical data
chemical_list: D014873:Water Pollutants