Bioremediation efficiency of indigenous seaweeds of Chennai coast in brackishwater system

Abstract

The accelerated development of high-density brackishwater shrimp farming necessitates the importance of bioremediation. Seaweeds have the potential to reduce nutrients from aquaculture systems and provide extra income when species of economic importance are used. Identification of suitable seaweed species which is locally available in abundance with bioremediation capacity in brackishwater system is paramount, and the present study addresses this issue. An exploratory monthly survey was undertaken in three brackishwater systems in Chennai coast viz. Muttukadu lagoon, Vennangupattu Lake and Pulicat Lake from March 2018 to February 2019 which led to a focus on species of the family Gracilariaceae. Identification of the species through taxonomical and molecular observations confirmed that seaweed from Muttukadu lagoon and Vennangupattu Lake is Agarophyton tenuistipitatum and that from Pulicat Lake is Hydropuntia edulis. Evaluation of the bioremediation potential of these two species indicated that they were similar with respect to ammonia and phosphate reduction efficiency whereas the specific growth rate of A. tenuistipitatum was significantly higher than H. edulis. Furthermore, the nutrient reduction efficiency and specific growth rate was significantly higher at biomass density of 3.5 and 4.5 g L−1 compared to 1.5 and 2.5 g L−1. It could therefore be concluded that A. tenuistipitatum could be utilised for bioremediation as well as culture in brackishwater system at a biomass density ranging from 3.5 to 4.5 g L−1Not Available