西北太平洋黑潮主轴区浮游有孔虫的垂直分布及其古海洋学意义

我们对位于西北太平洋黑潮主轴区ＭＴＤ－０２站的１１个不同深度进行水平浮游拖网,并将采集到的活体浮游有孔虫(＞１２５μｍ)进行定量分析。结果表明,绝大多数活体浮游有孔虫生存于１００～２００ｍ以上的水体中,并集中分布于７５ｍ以上的水体。本站位８月份的最主要属种为：Ｇｌｏｂｉｇｅｒｉｎｏｉｄｅｓｒｕｂｅｒ,Ｇ．ｓａｃｃｕｌｉｆｅｒ,Ｎｅｏｇｌｏｂｏｑｕａｄｒｔｎａｄｕｔｅｒｔｒｅｉ和Ｇｌｏｂｉｇｅｒｉｎｉｔａｇｌｕｔｉｎａｔａ。次主要属种为Ｇｌｏｂｉｇｅｒｉｎｅｌｌａ　ａｅｑｕｉｌａｔｅｒａｌｉｓ,　ｇｌｏｂｉｇｅｒｉｎａｂｕｌｌｏｉｄｅｓ,Ｐｕｌｌｅｎｉａｔｉｎａｏｂｌｉｑｕｉｌｏｃｕｌａｔａ,Ｇｌｏｂｏｒｏｔａｌｉａｔｒｕｎｃａｔｕｌｉｎｏｉｄｅｓ,Ｏｒｂｕｌｉｎａｕｎｉｖｅｒｓａ和Ｇ．ｃｏｎｇｌｏｂａｔｕａ。这些种在不同的深度其产出量大不相同,但绝大多数均在叶绿素最为丰富的２５ｍ处显示出最大值。这表明食物来源是控制浮游有孔虫在ＭＴＤ－０２站垂直分布的最主要因素。另外,Ｇｌｏｂｉｇｅｒｉｎｅｌｌａａｅｑｕｉｌａｔｅｒａｌｉｓ和Ｐｕｌｌｅｎｉａｔｉｎａｏｂｌｉｑｕｉｌｏｃｕｌａｔａ两个种在温跃层的底部５０ｍ处显

VERTICAL DISTRIBUTION OF PLANKTONIC FORAMINIFERS INKUROSHIO AREA OF NW PACIFIC AND ITS PALEOCEANO GRAPHIC IMPLICATIONS

Plankton net samples were obtained in August from 11 different water depthsbetween Om and 500m at station MTD-02 in the kuroshio area, western North Pacific.Our result shows that most Planktic foraminifera （> 125μm） lives in the upper100～200m water column, particularly in the above 75 meters. The most dominantspecies are composed of Globigerinoides ruber, G. sacculifer, Neogloboquadrinadutertrei and Globigerinita glutiaata. Secondly dominant species are Globigerinellaaequilateralis, Globigerina bulloides, Pulleniartina obliquiloculata, Globorotaliatruncatulinoides, Orbulina universa and Globigerinoides conglobatus. The samplescollected from different water depths show different standing stocks of these species,but indicating a preferred depth habitat of most species at 25m warer depth where thechlorophyll maximum zone develops. We suggest that food availability is among allthe most important factor controlling vertical distribution of planktic foraminifera instation MTD-02 in August. In addition, Globigerinella aequilateralis and Pulleniatinaobliquiloculata show their Peak occurrence at 50m depth, corresponding to the bottomof the thermocline and a secondary high value of chlorophyll concentration. Fourspecies belonging to the genus Globorotalia show high standing stocks in waterdepths between 75m and 500m, far below the thermocline. These results are ofpaticular significance in reconstructing vertical structure of the paleo-Kuroshio.