Compost extract as a nutrient source for Algal cultures

Abstract

Aquaculture is an efficient protein production activity that needs to be encouraged in order to reduce fishing pressure towards native fishes. The use of organic compost extract for algal cultures comes about as an ecological alternative reusing solid organic residuals. The present study tested the influence of culture mediums on the growth and development of the microalgaes Dunaliella marina and Nitzschia closterium on laboratory. Two culture treatments were tested: marine water with Conway medium, marine water with a compost extract medium and only marine water (tested as a without enrichment treatment). Higher densities of D. marina were observed on the Conway medium, but densities above 1.5×106 cells.mL-1 were frequently observed on the compost extract medium. N. closterium showed an initial stage of adaptation on both culture mediums and a higher initial density on the compost extract medium. The compost extract medium is an important source of nutrients that can be further used to cultivate algal masses for aquaculture and other uses, therefore providing framework for the reuse of domestic wastewater residuals and, thus, contributing to environmental conservation. © 2013 de Oliveira FMF, et al.