Nutrients Variation in Reclaimed Island of Southern Peninsular Malaysia

All living organisms required the nutrients phosphorus and nitrogen for their metabolism, growth and reproduction including seagrass ecosystem. Seagrass required dissolved inorganic nitrogen (N) and phosphorus (P) to maintain growth, where ammonium is considered as the main source of nitrogen, while the main phosphorus sources is phosphate. However, the nutrient cycling process was disturbed by anthropogenic activities. Reclaimed island near to seagrass bed affected the sedimentation and indirectly impacted the nutrient cycling. The purpose of this study is to investigate the nutrient variation in seawater from seagrass meadow. The study was conducted at Merambong seagrass meadow located between the Causeway second link and the Pulau Merambong, Southwest of Johor. Samples were well collected bimonthly from August 2016 until June 2017 and from 10 sampling points. The nutrients studied were including total ammonium nitrogen (TAN), nitrate nitrogen, nitrite nitrogen and soluble reactive phosphorus (SRP). All the nutrients results were compared with Malaysia Marine Water Quality Criteria and Standard (IMWQS). The lowest concentration (2.3 ppb) of nitrite was observed in South area in June 2017 whereas the highest concentration (40.8 ppb). The highest concentration was 32.5 ppb (North) in April 2017 and the lowest concentration was 4.7 ppb in August 2016. In April 2017, low ammonium concentration was 3.5 ppb in North. The highest concentration (57.8 ppb) was detected in North area in October 2016. The highest concentration was detected in North area with 321.8 ppb whereas exceeded the limit (75 ppb) and the lowest concentration was 16.1 ppb in August 2016 of South area. In general, the results of this study show the nutrients concentration in all sampling duration are below the limit lined by IMWQS except for phosphorus concentration detected in June 2017

Effect of Mixing on the Density and Chlorophyll A Content on Botryococcus Sp.

Optimization of the growth of microalgae is essential due to demand for high biomass yields. In addition, the methods to estimate the growth (as cell density or biomass) of microalgae are tedious. The normal methods include cell counts, optical density, chlorophyll a and ash free dry weight. However, at least two of these methods were done together for every growth experiment to get a better result. Therefore, this study investigates the effect of mixing as one of the many factors that determines the growth of microalgae, Botryococcus sp. In addition, three different methods to estimate the growth (in terms of cell density or biomass) will be utilized.  Three different treatments on the effect of mixing were employed (T1 using aeration; T2 manual hand shake two times daily; T3 no aeration and shaking) for these experiments. The experiment was carried out under outdoor conditions with temperature ranging from 25.8°C to 35.5°C, light intensity from from 200 Lux to 18000 Lux and pH of 7 to 8 units for 24 days using Bold basal medium (BBM) as growth media. Microalgae biomass was estimated by optical density, chlorophyll a and cell count using haemocytometer. The highest density of Botryococcus sp. was achieved (10.74 x 106 cell ml-1day-1; OD of 3.246 at 680nm; 0.7843 mg L-1day-1 chlorophyll a) with aeration. Whereas, the lowest (2.78 x 106 cell ml-1day-1; od 1.007 (680nm); chlorophyll a 0.1586 mg L-1day-1) and (3.07 x 106 cell ml-1day-1; od 0.999 (680nm); chlorophyll a 0.1545 mg L-1day-1)  with shaking and no aeration, respectively. There exist a positive linear relationship between cell counting and optical density (R2=0.96); cell count and chlorophyll a (R2=0.95); and optical density and chlorophyll a (R2= 0.98) were observed. The result of this study suggested that constant aeration is required by the microalgae, Botryococcus sp. for growth in terms of cell density and biomass