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Avoidance response is a well-known mechanism for escaping environmental stress. For organisms with reduced active movement, such as benthic microalgae, drifting could be a specifically selected mean of avoiding less favorable environments. To test this hypothesis, a system was developed to assess if hypo-saline stress triggers drift in the estuarine benthic diatom Cylindrotheca closterium. Concurrently, the effects of salinity on growth inhibition were also investigated in order to compare the sensitivity of this endpoint with the drift response, and to estimate the immediate population decline caused by both drift and population growth responses. It was verified that the salinity value that inhibited the algal population growth by 50% (IGS50) was 19, while the salinity value that triggered the drift response by 50% of the population (TDS50) was 15. These results indicate that drift is an identifiable response triggered to escape stressful environments. The combination of the two responses (population growth and drift) showed that population decline based exclusively on the inhibition of population growth may result in an underestimation of the risk, compared with the decline when drifting to avoid stress is also taken into account.

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Poor soil management and intensive use of pesticides causes serious damage to soil and water quality in Brazil. To confirm this, two studies were conducted in an area with intensive farming in Southern Brazil with objectives to evaluate the level of pesticides in the river adjacent to the

Peatlands are a transitional environment between terrestrial and aquatic ecosystems that provide essential hydrological, ecological, and biogeochemical. Peatlands have been recognized as important environmental matrices in the storage of organic carbon and water. However, little is known in the literature about the influence of peatlands on the quality of surface water. Therefore, this study aims to evaluate the water quality from peatlands in the spring of the Rio Campo Belo, in Itatiaia National Park, Itatiaia-Brazil. The spring water quality from peat profiles was based on the determinations of the temperature, dissolved oxygen (DO), electrical conductivity, pH, turbidity, dissolved organic carbon (DOC), total organic carbon (TOC), silica, ions, and trace elements (Al, Sb, As, Cd, Co, Cu, Cr, Sn, Fe, Mn, Mo, Ni, V, Ga, Rb, Sr, and Zn) on spring water and peat core samples. The highest DO values ​​observed in the spring waters that leachate water and may be related to the lower water temperature, as well as the movement of water. The DOC values were relatively low suggesting no difference between the spring water and the water leached (1.6 and 1.7 mg l-1, respectively). Higher values of ions and trace elements in the leaching water from core peat demonstrate a greater contribution of the peatland to the concentration of these ions in spring water. An increase in TOC peatland did not cause an increase in pH, however, the removal of organic matter promoted an increase in pH.

Peatlands are a transitional environment between terrestrial and aquatic ecosystems that provide essential hydrological, ecological, and biogeochemical. Peatlands have been recognized as important environmental matrices in the storage of organic carbon and water. However, little is known in the literature about the in uence of peatlands on the quality of surface water. Therefore, this study aims to evaluate the water quality from peatlands in the spring of the Rio Campo Belo, in Itatiaia National Park, Itatiaia-Brazil. The spring water quality from peat pro les was based on the determinations of the temperature, dissolved oxygen (DO), electrical conductivity, pH, turbidity, dissolved organic carbon (DOC), total organic carbon (TOC), silica, ions, and trace elements (Al,