ABSTRACT
Fewer studies have assessed the outdoor cultivation of Spirulina maxima compared with S. platensis, although the protein content of S. maxima is higher than S. platensis. Spirulina growth medium requires an increased amount of NaHCO3, Na2CO3, and NaNO3, which increases the production cost. Therefore, the current study used a low-cost but high-efficiency biomass production medium (Medium M-19) after testing 33 different media. The medium depth of 25 cm (group A) was sub-divided into A1 (50% cover with a black curtain (PolyMax, 12 oz ultra-blackout), A2 (25% cover), and A3 (no cover). Similarly the medium depths of 30 and 35 cm were categorized as groups B (B1, B2, and B3) and C (C1, C2, and C3), respectively, and the effects of depth and surface light availability on growth and biomass production were assessed. The highest biomass production was 2.05 g L-1 in group A2, which was significantly higher (p < 0.05) than that in all other groups and sub-groups. Spirulina maxima died in B1 and C1 on the fifth day of culture. The biochemical composition of the biomass obtained from A2 cultures, including protein, carbohydrate, lipid, moisture, and ash, was 56.59%, 14.42%, 0.94%, 5.03%, and 23.02%, respectively. Therefore, S. maxima could be grown outdoors with the highest efficiency in urea-enriched medium at a 25-cm medium depth with 25% surface cover or uncovered.
Subject(s)
Biomass/analysis , Biomass/chemistry , Biomass/growth & development , Biomass/instrumentation , Biomass/metabolism , Biomass/methods , Culture Media/analysis , Culture Media/chemistry , Culture Media/growth & development , Culture Media/instrumentation , Culture Media/metabolism , Culture Media/methods , Culture Techniques/analysis , Culture Techniques/chemistry , Culture Techniques/growth & development , Culture Techniques/instrumentation , Culture Techniques/metabolism , Culture Techniques/methods , Spirulina/analysis , Spirulina/chemistry , Spirulina/growth & development , Spirulina/instrumentation , Spirulina/metabolism , Spirulina/methods , Urea/analysis , Urea/chemistry , Urea/growth & development , Urea/instrumentation , Urea/metabolism , Urea/methodsABSTRACT
Changes in soft-bottom macrobenthic communities and the effects of anthropogenic disturbances were studied. We compared biological and environmental samples during and after bridge construction (DBC and ABC). Significant differences were detected in sediment composition at three stations, although hydrographic conditions were similar for DBC and ABC samples. From DBC to ABC, the number of species and density of macrobenthic fauna tended to decrease, whereas biomass increased. Non-metric multidimensional scaling (MDS) analysis identified two sampling period groups from eight temporal samples, plus three station groups and one station from 12 spatial samples, which corresponded to macrobenthic faunal assemblages and theircharacteristic species. In addition, contributions of variables to similarity showed that the DBC and ABC samples differed significantly in the distribution of characteristic species and proportion of polychaete trophic groups, suggesting that the macrobenthic community structure was a factor affecting sediment disturbance caused by bridge construction.