Abstract
Algal assay procedure and algal growth potential test (AGP test) are adopted as the method to evaluate the state of eutrophication. Then, it is necessary to examine the precision of these procedures. The precision and reproducibility of these procedures that use the most general phytoplankton (Skeletonema costatum and Heterosigma akashiwo) in the coastal area of our country were checked. The determination of growth limiting nutrient of algae by multiple-nutrient tests was checked.
The results are following.
1) Coefficients of variation of the maximum standing crop were less than 10% at the repeat test.
2) The reproducibility of proliferation was not influenced by an addition of various nutrition on multiple-nutrient tests.
3) Age of the phytoplankton that was used as a source of inoculum did not exert an influence to the result of tests.
4) Proliferation of phytoplankton complied with Liebig's “Law of the Minimum” and the maximum standing crops were proportional to the amount of limiting nutrient available.
These results showed that it was possible to evaluate the progress of eutrophication and determine the growth limiting nutrient of algae with AGP test.
