Análise temporal e espacial de nutrientes na Praia do Futuro, Fortaleza CE, Brasil

Abstract

In the marine environment nutrients perform an important function; they are assimilated by phytoplankton which is the base of the food chain of the entire environment. The main nutrients found in oceans are inorganic nitrogen: ammonium, nitrite, nitrate, besides phosphate and reactive silica. The objectives of this study were to assess the temporal and spatial variation of nutrients in “Praia do Futuro, Fortaleza-CE” and the relationship of the concentration of nutrients with the appearance of accumulations of diatomaceous. They were collected monthly from July 2011 to June 2012, at low tide and high tide at two different points Beach, point 1 (3 ° 43'27, 05 "S 38 ° 27'34", 46W) and point 2 (3 ° 45'19, 77 "S 38 ° 26'37, 12" W). They were made in laboratory determination of nitrite, nitrate, ammonia and orthophosphate. In field were determined: air temperature, water and oxygen (saturated and dissolved) in Aquaculture oximeter Bernauer, YSI F-1550 and salinity in a refractometer hydrometer ATAGO. The method utilized to determine the ammonia hardly detected that nutrient concentrations in water collected, found orthophosphate and nitrite concentrations consistent with that expected for this environment, but the nitrate was smaller, including that the nitrite. The nitrate concentrations were lower in the months in which appeared the accumulation of diatomaceous, however, nitrite concentrations were higher which shows that the phytoplankton have possible preference in assimilate nitrate. In the month that occurred the accumulation of diatomaceous with maximum biomass, the orthophosphate concentrations were higher.