Microartrópodes do solo em um agroecossistema irrigado com água da exploração de petróleo no semiárido

Abstract

In arid and semiarid lands with continental oil fields, the water obtained with oil, known as "produced water" (PW), has been suggested as an alternative source for irrigation. Because the relevance of microarthropods assemblage for the soil, in this study was evaluated the disturbances promoted by the PW on those edaphic organisms. In Chapter I, was assessed whether the irrigation with PW filtered and PW filtered and then treated by reverse osmosis, comparing with groundwater from Açu aquifer, changes the mesofauna in sunflower and castor bean crops during dry and rainy seasons. PW and seasonality changed the abundance and richness in castor bean. In the sunflower crop, the assemblage structure was different from the aquifer in PW treated by reverse osmosis during the rainy season, while in castor bean that difference occurred in both seasons. Disturbances promoted by PW on mesofauna can be used for environmental monitoring of irrigation. In Chapter II the effects of PW filtered, PW filtered and then treated by reverse osmosis and the glutaraldehyde, commonly used in treatment of PW by reverse osmosis, on microarthropods taxa was assessed in an ornamental pineapple crop. Ecotoxicological tests evaluated the survival and reproduction of Folsomia candida and Enchytraeus crypticus on soil samples collected in the treatments after a year of irrigation and in soil contaminated with glutaraldehyde. PW influenced Hymenoptera, Cosmochthonius sp. and Entomobryomorpha. The PW treated by reverse osmosis reduced reproduction of F. candida and E. crypticus and the PW filtered affected the reproduction of E. crypticus. Glutaraldehyde reduced the reproduction of F. candida. Our study reveals that AP and glutaraldehyde affect the mesofauna taxa reducing their reproduction. In chapter III the environmental responses of total microarthropod and Mesostigmata mites were compared. Microarthropods were assessed in irrigated plots under castor bean and sunflower cultivation, and native vegetation during the dry and rainy seasons. The response of the two assemblages to irrigation and seasonality was similar. Mites were affected by seasonality in the sunflower and by irrigation in castor bean crops, while the total microarthropod have been affected by both factors. Mesostigmata mites or total microarthropd assemblages can be assessed to monitor seasonality and land use.