Algal Growth Potential and the limiting nutrient in Mikawa Bay

Abstract

The Algal Growth Potential (AGP) of water samples collected off Gamagori in Mikawa Bay was measured from May 1978 through February 1979, and the limiting nutrient was determined using regression analysis and enrichment bioassays. The surface and bottom water samples had AGP that produced increments of chemical oxygen demand (ACOD) of 2.1mg1-1 and 3.1mg1-1, respectively, on average. These values o{ ACOD correspond to 46 o.~ and 97 % of the average COD values of the raw water samples at the surface and bottom, respectively. Seasonal changes of AGP showed a close correlation with those of dissolved inorganic nitrogen (DIN)concentration. Enrichment bioassays showed that DIN was the most deficient nutrient. The DIN:phosphate-phosphorus (PO~3--P) ratios and DIN: dissolved phosphorus (DP) ratios in the water samples were below the cellular N:P ratios of the natural algal populations. These results suggest that AGP was mainly limited by DIN concentration.

ASM Sci. J., Vol. 4, No. 1, 2010

“…According to Kondol et al (1984), algal assay is a useful method for identifying growth limiting nutrient. Estimation of AGP is of interest to estimate the maximum growth of useful species.…”