Biochemical and microbiological tools for the evaluation of environmental quality of a coastal lagoon system in Southern Brazil

Abstract

This study aimed to evaluate the environmental quality of surface water of the Maricá Lagoon System through physicochemical, biochemical and microbiological parameters, in order to assess its environmental quality. Marine influence over the system was evidenced by the salinity and temperature gradients, where the most distant point, in Maricá Lagoon, presented the largest protein, lipid and biopolymeric carbon concentrations. Biopolymers, with predominance of lipids, presented a pattern that differs from the literature for coastal sediments. The concentration of thermotolerant coliforms characterised Maricá Lagoon and Boqueirão Channel as unfit for bathing (60.0 and 66.3 cells x mL(-1), respectively). The bacterioplankton in the system proved to be predominantly heterotrophic, a consumer of organic matter, with fermentative, denitrifying and sulfate-reducing metabolism. No esterase enzyme activity was detected, despite the presence of active metabolism, measured by the electron transport system (average of 0.025 µg O2 x h(-1) x mL(-1)). The bacterial biomass (autotrophic, heterotrophic and coliforms), bacterial respiratory activity and biopolymer parameters evinced a spatial degradation pattern in the Maricá Lagoon System, where the points with less water renewal are the most impacted.

Assessment of the Trophic State of Saquarema Lagoonal System, Rio De Janeiro (Brazil)

“…Values of dissolved oxygen recorded in SLS were higher than that found in other Rio de Janeiro lagoons such as Maricá (Oliveira et al, 1955;Guerra et al, 2011;Silva et al, 2014), Araruama (Debenay et al, 2001) and Itaipu lagoons . The values obtained in SLS indicated a favorable environment to the establishment of aerobic organisms of several trophic levels, since they require oxygen for their functions.…”

Organic Compounds as Proxies of the Sedimentary Environmental Quality of the Maricá-Guarapina Lagoon System (Se, Brazil)

“…The recorded physical-chemical parameters vary gradually depending on the proximity to Ponta Negra Channel (Fig. 1), where the MGLS connects the sea, as described by several authors (Kjerfve and Knoppers, 1999;Bomfim et al, 2010;Guerra et al, 2011). The current mean salinity value recorded in Guarapina Lagoon (16.5) falls within the range documented in the literature (7.0-19.0) (Kjerfve and Knoppers, 1999;Guerra et al, 2011).…”

“…However, in the MGLS, depending on the station, it can be found larger ranges of water temperature. Guerra et al (2011), for instance, recorded mean temperatures 6°C lower than that found, in this work, in Guarapina Lagoon.…”

“…1), where the MGLS connects the sea, as described by several authors (Kjerfve and Knoppers, 1999;Bomfim et al, 2010;Guerra et al, 2011). The current mean salinity value recorded in Guarapina Lagoon (16.5) falls within the range documented in the literature (7.0-19.0) (Kjerfve and Knoppers, 1999;Guerra et al, 2011). In Barra Lagoon, the mean salinity value recorded in this work (2.3) is also in the range of the previously noticed values of 1.0 (Kjerfve and Knoppers, 1999) and 5.5 (Guerra et al, 2011).…”

Protists and bacteria interactions in the presence of oil

“…Dissolved inorganic and organic substrates can be metabolized with high substrate affinity and specificity. Particulate organic matter can be decomposed in close contact with the substrate by using hydrolytic enzymes (Silva et al 2010, Guerra et al 2011. Other than oxygen, microorganisms use alternative electron acceptors (nitrate, manganese, iron, sulfate, and carbon dioxide) for the assimilation of organic material (Edwards et al 2005).…”