Abstract
Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.
Highlights
As a consequence of the input of nutrients, inorganic and organic material, relative shallowness, high penetration of solar radiation, and frequent water column mixing, coastal lagoons usually present high rates of primary and secondary productivities (Kjerfve, 1994; Castel et al, 1996)
Ammonium and orthophosphate showed a reduction from the first day to the following day and N:P values presented an increase
Chlorophyll-a concentrations in the enriched treatment showed a positive relationship with the phosphorus forms, supporting the possibility of phosphorus limitation
Summary
As a consequence of the input of nutrients, inorganic and organic material, relative shallowness, high penetration of solar radiation, and frequent water column mixing, coastal lagoons usually present high rates of primary and secondary productivities (Kjerfve, 1994; Castel et al, 1996) Such ecosystems cover approximately 13% of coastal areas worldwide and in Brazil they occur almost all along the coastline from the State of Rio Grande do Sul to the State of Maranhão (Schäfer, 1992). Non-treated sewage disposal is usually the most important disturbance This provides the environment with excess nutrients (especially phosphorus and nitrogen), which may enhance the eutrophication process, in several cases leading to massive phytoplanktonic development and the occurrence of distrophic crises (Faria, 1993; Suzuki, 1997). This causes a temporary disappearance of aquatic organisms (Faria, 1993)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Brazilian journal of biology = Revista brasleira de biologia
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
