Marco Valério Jansen Cutrim

Using a toxicity test with Ruppia maritima (Linnaeus) to assess the effects of Roundup.

Glyphosate, the active ingredient in Monsantos broad-spectrum herbicide Roundup, consists of one of the most used pesticides worldwide, but its effects on the marine flora are still not well understood. Were examined Roundup toxic effects on Ruppia maritima specimens collected from Jansen Lagoon (São Luís, MA, Brazil) and acclimatized under laboratory conditions. The numbers of new and dead leaves, the root and leaf length, the chlorophyll a content, and the weight of R. maritima branches were determined before and after exposure to different Roundup concentrations for seven days. High concentrations caused a significant lethal effect. In addition, significant changes were observed in the wet and dry weights, the number and length of the leaves, and the chlorophyll a content. Leaf elongation was observed in the branches exposed to low concentrations, and this change was likely activated as a compensatory mechanism. The results indicate that high concentrations of this herbicide may compromise estuarine flora.

Aquatic life protection index of an urban river Bacanga basin in northern Brazil, São Luís - MA

Bacanga River Basin faces environmental problems related to urbanization and discharge of untreated domestic sewage, which compromise its ecosystem health. Due to the small number of studies that assessed its water quality, the present study aimed to assess the current status of this ecosystem based on the aquatic life protection index. Samples were carried out every two months, in a total of six events, in six sites along the basin, where the water samples were collected to assess physicochemical parameters and calculate the trophic state index and the index of minimum parameters for the protection of aquatic communities. The data were also compared with values determined by the resolution National Environment Council - CONAMA 357/05. Our results reveal significant changes in the water quality of Bacanga River Basin. An increase in nutrients and chlorophyll-a concentration led it to eutrophication. The surfactant values were high and put in danger the aquatic biota. Dissolved oxygen rates were below the values allowed by the resolution in most sites sampled. The current water quality is terrible for the protection of aquatic life in 61.92% of the sites sampled.

COMUNIDADE ICTIOPLANCTÔNICA DA BACIA HIDROGRÁFICA DO RIO BACANGA NA CIDADE DE SÃO LUÍS, BRASIL

This work was developed in the Bacanga river basin, from April 2012 to February 2013, with six established collection points, with the aim of characterizing the environment and the ichthyoplankton community. Therefore, measurements were made of physical-chemical parameters of the water. Ichthyoplankton samples were collected in horizontal hauls with the aid of a plankton net conical-cylindrical mesh of 300 micrometers. Specific gravity was calculated for fish larvae and biotic and abiotic data were statistically interrelated. The eggs and larvae were present in all months of sampling. Fish larvae in the basin study showed a spatial pattern of marine influence, and the collection points near the mouth of the river are important environments used as spawning and early development, working as a nursery for some species of marine fish.