Trophic state, ecosystem efficiency and biodiversity of transitional aquatic ecosystems: analysis of environmental quality based on different benthic indicators

The present study aims to assess the environmental quality of six estuaries in north-eastern Brazil, using biochemical composition and quantity of organic matter in tropical sediments. Samples were collected monthly during spring low tide from August 2011 to July 2012, in the mid-littoral. Concentrations of organic matter and its biochemical composition reflected the degree of anthropogenic pressure. Although total concentrations of proteins and carbohydrates were similar among estuaries with contrasting levels of anthropogenic pressure, the protein to carbohydrates (PRT : CHO) ratio effectively reflected the trophic state of these areas. PRT : CHO ratios >1 were observed in all studied areas suggesting eutrophic conditions or an initial stage of eutrophication in all of them. Low Chl-a/Phaeo ratios may be associated with the level of eutrophication of each area, however it may also reflect the natural productivity or the presence of mangrove debris. These results were compared with those obtained in previous environmental assessments of the same estuarine areas using the AZTI Marine Biotic Index and monitoring reports showing good agreement. The present study confirmed for the first time in tropical estuarine areas that the biochemical approach can be successfully used to assess the trophic state of the benthic compartment.

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Mercury cycling in aquatic ecosystems and trophic state-related variables — Implications from structural equation modeling

The Science of The Total Environment ◽

10.1016/j.scitotenv.2014.08.036 ◽

2014 ◽

Vol 499 ◽

pp. 62-73 ◽

Cited By ~ 18

Author(s):

Curtis D. Pollman

Keyword(s):

Structural Equation Modeling ◽

Aquatic Ecosystems ◽

Structural Equation ◽

Trophic State ◽

Equation Modeling ◽

Mercury Cycling

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Effects of Sewage Discharge on Trophic State and Water Quality in a Coastal Ecosystem of the Gulf of California

The Scientific World JOURNAL ◽

10.1155/2014/618054 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 10

Author(s):

Héctor Hugo Vargas-González ◽

José Alfredo Arreola-Lizárraga ◽

Renato Arturo Mendoza-Salgado ◽

Lía Celina Méndez-Rodríguez ◽

Carlos Hernando Lechuga-Deveze ◽

...

Keyword(s):

Water Quality ◽

Coastal Water ◽

Environmental Quality ◽

Water Body ◽

Gulf Of California ◽

Trophic State ◽

Coastal Ecosystem ◽

Urban Wastewater ◽

Receiving Water

This paper provides evidence of the effects of urban wastewater discharges on the trophic state and environmental quality of a coastal water body in a semiarid subtropical region in the Gulf of California. The concentrations of dissolved inorganic nutrients and organic matter from urban wastewater primary treatment were estimated. La Salada Cove was the receiving water body and parameters measured during an annual cycle were temperature, salinity, dissolved oxygen, nitrite, nitrate, ammonia, orthophosphate, and chlorophylla. The effects of sewage inputs were determined by using Trophic State Index (TRIX) and the Arid Zone Coastal Water Quality Index (AZCI). It was observed that urban wastewater of the city of Guaymas provided 1,237 ton Nyr−1and 811 ton Pyr−1and TRIX indicated that the receiving water body showed symptoms of eutrophication from an oligotrophic state to a mesotrophic state; AZCI also indicated that the environmental quality of the water body was poor. The effects of urban wastewater supply with insufficient treatment resulted in symptoms of eutrophication and loss of ecological functions and services of the coastal ecosystem in La Salada Cove.

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Combined Effects of Chemicals: An Essential Element in Risk Extrapolation for Aquatic Ecosystems

Water Science & Technology ◽

10.2166/wst.1992.0324 ◽

1992 ◽

Vol 25 (11) ◽

pp. 441-447 ◽

Cited By ~ 6

Author(s):

M. A. van der Gaag

Keyword(s):

Environmental Quality ◽

Aquatic Ecosystems ◽

Scientific Evidence ◽

Essential Element ◽

Quality Criteria ◽

Toxic Action ◽

Toxic Effects ◽

Combined Effects ◽

Environmental Criteria ◽

Low Concentrations

Joint toxic action of compounds in aquatic ecosystems is a factor that should be taken into consideration when environmental quality criteria are derived from the outcomes of toxicological tests in the laboratory. Many risk-extrapolation procedures calculate so-called ‘safe' environmental criteria for single compounds, regardless of possible interactions. However, additivity of toxic effects of different compounds, even at very low concentrations has been demonstrated by many different researchers. The possibility to integrate the aspect of joint toxic action into risk-extrapolation protocols is discussed against the background of the available scientific evidence.

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