Respostas a distúrbios ambientais: o uso de esponjas marinhas como modelo biológico

Abstract

Sponges are important components of tropical marine ecosystems and are considered to be good ecological indicators and producers of bioactive compounds. In this context, the objectives of this study were: to present gaps in the review studies on the responses of sponges to certain environmental disturbances; to perform aapplied study correlating an environmental impact relative index (EIRI) to the metabolic responses of two sponges in Ilha Grande Bay, Desmapsamma anchorata Carter, 1882 and Mycale angulosa (Duchassaing e Michelotti, 1864), also observing if this index can be considered a predictive variable to other factors commonly tested in environmental assessments; to evaluate the responses of the D. anchorata sponge to environmental disturbances: exclusion of predators, nutrient enrichment (top-down and bottom-up), shading through growth and production of secondary metabolites; and to evaluate the existence of a trade-off between growth and chemical production of D. anchorata. In situ Raman spectroscopy analysis of the manipulated tissues of D. anchorata revealed differences in their chemical composition between the environments with the highest and lowest IRIA, but the same was not observed for the metabolite composition of M. angulosa.The review chapter found that, to date, studies are geographically concentrated, and that responses are very restricted to sponge growth and abundance. This shows the importance of integrating these results into the dynamics of production of chemical defenses. There was a positive relationship between nutrient concentration and EIRI. In situ Raman spectroscopy analysis of the manipulated tissues of D. anchorata revealed differences in their chemical composition between the environments with the highest and lowest EIRI, but the same was not observed for the metabolite composition of of M. angulosa. A temporal variation was observed in the growth rates in the 131-day bioassay period.The sterols (3,22E)-colest-5,22-dien-3-ol,(3)-colest-5-en-3-ol,(3)-ergost-5-en-3-ol, (3,24Z)-24-propylidene-colesta-5-en-3-ol, (3,22E)-ergost-5,22-dien-3-ol, (3)-colest-5,24-dien-3-ol, (3,22E)-stigmast-5,22-dien-3-ol), e (3,24E)-stigmast-5,24(28)-dien-3-ol, (3,24Z)-stigmast-5,24(28)-dien-3-ol, colesta-5-en-3-one were shown to be efficient as stress biomarkers for nutrient enrichment, exclusion of predators and by shading. Desmapsamma anchorata showed no significant relationship between metabolic production and growth. The results indicate the use of D. anchorata as a biological model to detect changes in benthic marine communities.