Studies on the Oceanographic and Planktological Characteristics of the Bay of Ômura (IV). The Relation of Water Masses and Plankton Flora

摘要

Present paper refers to the relation of water masses and plankton flora, mainly diatoms, of the Bay of Ômura in August 1956.As shown in Figs.3&4, the line of st.1 to st.2 divides the waters into 2 portions,i.e.the outer (chlorinity: 18.00% ) and the inner (chlorintiy: 18.00%) We analyzed the plankton flora from a viewpoint how influence the differences of the water masses upon the quality, the quantity and the morphology.The results obtained are as follows: 1.The specific compositions were similar both in the outer and in the inner (Tab.2). 2.The concentric distribution is shown in Fig.5.It doesn't depend presumably on the water masses. 3.Figs.6, 7 & 8 show the frequencies of valve-width (in a broad girdle view) of Chaetoceros didymus var. protuberans, Ch. didymus var. anglica and Ch. lorenzianus at each station on the A-line (Fig.1).It is evident from them that Ch. lorenzianus shows the variations between the outer and the inner, ranging in the former 24-42μ and in the latter 7-14μ, though there are no morphological differences in two varieties of Ch. didymus. From viewpoints above mentioned, finally, the relation of water masses and plankton flora is very complex and doesn't lead us to any conclusion.