Catastrophic shifts in the aquatic primary production revealed by a small low-flow section of tropical downstream after dredging

Marotta, H. (author): University of Federal Fluminense, Brazil; University of Federal Fluminense, Brazil; University of Federal Fluminense, Brazil

Enrich Prast, Alex (author): Linköpings universitet,Tema Miljöförändring,Filosofiska fakulteten,University of Federal Rio de Janeiro, Brazil

(creator_code:org_t)

2015-11-24
2015
English.
In: Brazilian Journal of Biology. - : INT INST ECOLOGY. - 1519-6984 .- 1678-4375. ; 75:4, s. 804-811

Related links:: https://liu.diva-por... (primary) (Raw object); show more...; http://www.scielo.br...; https://urn.kb.se/re...; https://doi.org/10.1...; show less...

Abstract Subject headings

Dredging is a catastrophic disturbance that directly affects key biological processes in aquatic ecosystems, especially in those small and shallow. In the tropics, metabolic responses could still be enhanced by the high temperatures and solar incidence. Here, we assessed changes in the aquatic primary production along a small section of low-flow tropical downstream (Imboassica Stream, Brazil) after dredging. Our results suggested that these ecosystems may show catastrophic shifts between net heterotrophy and autotrophy in waters based on three short-term stages following the dredging: (I) a strongly heterotrophic net primary production -NPP- coupled to an intense respiration -R- likely supported by high resuspended organic sediments and nutrients from the bottom; (II) a strongly autotrophic NPP coupled to an intense gross primary production -GPP- favored by the high nutrient levels and low solar light attenuation from suspended solids or aquatic macrophytes; and (III) a NPP near to the equilibrium coupled to low GPP and R rates following, respectively, the shading by aquatic macrophytes and high particulate sedimentation. In conclusion, changes in aquatic primary production could be an important threshold for controlling drastic shifts in the organic matter cycling and the subsequent silting up of small tropical streams after dredging events.

About the subject

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.