Comparison on nutrient levels in Reef Aquaria and coastal waters

Phosphate and nitrate cycles are two of the most important biogeochemical cycles in maintaining coral reef stability. These nutrients are vital for the survival of marine organisms in the ecosystem. In this study, nutrient level variations in a sump tank of an aquarium system were observed over six weeks to determine if nutrient levels mimic those over natural reefs and if nutrients will stabilize over time. Three samplings for six weeks, one sampling every two weeks, were done to monitor the nutrient levels. Nutrient concentrations were determined using ascorbic acid method for phosphate and cadmium reduction method for nitrate. Two-way ANOVA and Post-hoc Tukey tests were used to analyze the results using the p-value \u3c 0.05. The filtration effectivity experiment showed that the sump tank was able to filter nitrate more than phosphate. The former was more evenly distributed and had lower concentrations on the third sampling. There was a significant decrease in nitrate (p-value = 0.015) and significant increase in phosphate (p-value = \u3c0.0001). The comparison experiment showed phosphate concentrations in chamber 1 and chamber 4 had a significant increase over time with p-values of 0.0022 and 0.0215, respectively. The increase in phosphate concentration was mainly due to accumulation of phosphate laden sediments brought by agricultural and urban runoff making the phosphate harder to filter. The phosphate concentration of the reef was significantly lower than that of chamber 1 in sampling 3 (p-value= 0.0514) but there was no significant difference between nitrate concentrations in the reef and in the tank. Thus, the aquarium did not completely mimic the reef because phosphate was increasing while nitrate was still tending towards normal levels