Studies of glucosidase activities from surface sediments in mangrove swamp

Abstract

Four transects including sixteen stations were established in the Fugong mangrove (117 degrees 54'-117 degrees 55'E, 24 degrees 22'24 degrees 24'N) of the Jiulong River Estuary, Fujian, China. Besides geochemical characterization and estimation of bacterial abundances, the distribution of alpha- and beta-glucosidase activity was studied to explore the degradation of carbohydrates which can be expected to occur in high quantities in mangrove systems. The distribution pattern of microbial alpha-glucosidase and beta-glucosidase activities was investigated using a fluorogenic model substrate (FMS) technique in order to allow better understanding of in situ enzyme activities, as well as their relation to bacterial biomass, metabolic activity and environmental factors in mangrove sediments. The results showed that the enzyme activities of alpha-glucosidase (10.839 similar to 100.86 mu mol g(-1) h(-1)) and beta-glucosidase (39.60 similar to 222.75 mu mol g(-1) h(-1)) varied among the different stations, and the enzyme activities of beta-glucosidase were higher than those of alpha-glucosidase at all stations. The extracellular enzyme activities were positively related to organic C, organic matter and bacterial abundance. In addition, the use of the FMS technique to measure extracellular enzyme activities of mangrove sediments could help us to evaluate their catabolic behavior in situ and so lead to a better understanding of the bacterial role in material cycle of mangrove swamp ecosystems. (C) 2008 Elsevier B.V. All rights reserved.