WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2015 35 (CONTINUED ON PAGE 36) The varied microhabitats of Wanggu River and Kendari Bay that receive high nutrient input from wastewater may therefore harbor a wide variety of warmwater tropical microalgal species. Further, this local diversity suggests that the region can be a source for a potentially wide variety of microalgal strains that might grow easily under various controlled conditions in the laboratory. Thus, the purpose of our study was to isolate and characterize the growth of local strains of microalgae from Kendari Bay that may be used in shrimp hatcheries and for other applications. In the long term, this research will be the basis for establishing a bank of microalgae in Indonesia to provide the scientific and commercial industry communities with varied local tropical strains of microalgae for various purposes. What We Did Sampling and Isolation. We collected water samples from the Wanggu River near the Talia Bridge and in the estuary in Kendari Bay (Fig. 2) in June and August 2013. June samples were denoted as Kb1 and the August samples were Kb2. Samples was filtered using plankton net (25-μm mesh diameter) and transported to the US in 25-mL Falcon tubes after being kept overnight at the Faculty of Fisheries and Marine Science Laboratory of Halu Oleo University in Kendari. We isolated the microalgae at the NOAA Milford Laboratory and Ocean Institute Laboratory, University of Rhode Island using flow cytometry and micropipet isolation techniques. Microalgal Culture. The Kendari Bay strains of microalgae were cultured in 50-mL culture tubes containing 20 mL of Guillard’s F/2 medium in four replicates (Fig. 3) at four salinity levels (20, 25, 30 and 35 psu). Tisochrysis lutea, Chaetoceros neogracile and Thalassiosira weissflogii were also cultured under similar conditions for comparison. Cultures were maintained in incubators at 28-30 C, under a 12:12 h light: dark cycle for 18 days. Identification and Growth Experiment. Scanning Electron Microscopy was used to obtain images of the microalgae and as a tool in identifying isolated strains. Cell size was analyzed using image analysis software (Nikon Imaging Software) to measure length, width and diameter of 50 representative microalgal cells. Cell densities of four replicates of cultured microalgae was measured every other day using a fluorometer (Model 10 AU Turner Designs Sunnyvale California, USA) and experimental FIGURE 3. Diagram of microalgae culture protocol representing one strain with four salinity levels (20, 25, 30 and 35 psu) tested.
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