The effects of Cyclina sinensis bioturbation on alkaline phosphatase (APA) and total microbial hydrolytic activities (MBA) in marine clam-shrimp integrated ponds.

Abstract

This study investigated the influence of Venus clam Cyclina sinensis bioturbation activities on the total benthic microbial and phosphatase activities and selected sediment properties: total phosphorous TP, total organic nitrogen-TON and total organic carbon-TOC. Sediments samples from clam-shrimp integrated-pond and non-clam integrated-pond were sampled for the study in which microbial activity (MBA) and alkaline phosphatase activity (APA), sediment organic contents: TP, TON, TOC, TOM and water quality parameter (dissolved oxygen, temperature, pH and moisture content were analyzed. The p-nitrophenyl phosphate disodium (p-NPP) and Fluorescein diacetate-(FDA) were adopted to measure APA and MBA respectively. Results indicated that microbial activity-MBA and alkaline-phosphatase activity-APA in sediments significantly increased in the pond cultured with clam/shrimp compared to non-clam cultured pond. Phosphate concentration increased significantly and varied among months (p<0.05) implying increased nitrogen concentration in the sediments. The concentrations of total organic nitrogen and total organic carbon didn't differ significantly among months and with the treatments (p>0.05), implying increased TON mineralization. Correlation analyses showed that there was positive correlation with the total microbial activity, alkaline-phosphatase activity, phosphorous concentration and organic matter content within the sediments bioturbated by the Venus clam. The results suggest that, the Venus clam sediment reworking mechanisms in sediment influenced the sediment microbial and APA activities and mineralization thereby affecting the pond alkaline phosphatase enzyme related activities.