判別分析からみた赤潮要因について

概要

論文の詳細を見る
For the purpose of explanation of the difference between red tide and non red tide from sea water parameters, discriminant analysis was applied to monthly observed marine data in the Ise bay from 1977 to 1982 (Red tide group: chl-a ≥50μg/l, non red tide group: chl-a ≤5μg/l). The most heavily weighing factor was COD after calculation, but this factor was trivial because of toodirect effect, therefore, discriminant function (Z) and Mahalanobis'distance (D2) were obtained bystepwise increasing method from seven parameters without COD, Z=0.276 sal-1.093 DO-7.450pH-1.49Ó PO4-P (1)D2=7.6403and factors were selected by above method, pH, sal, DO and PO4-P in the order named. Z is interesting formula, for it constructs oceanographical and eutrophic factors. In order to confirm validity obtained discriminant function, Eq. (1) was applied to observed data from 1980 to 1983. As the result of calculation, satisfactory result was obtained, and probability of miss classification was about 0.1-0.05. Moreover, this method was applied to group of diatoms and dinoflagel-late plankton. Obtained discriminant function and D2 wereZ=α•PO4-P(α=const.), D2=0.4098 (2)and this function was valuable according to the F-test. The importance of PO4-P was reaffirmed.
日本水産學會の論文