planktonn.浮游生物planktonic foraminifers浮游的有孔虫planktonic foraminifera浮游有孔虫planktonic microorganism浮游微生物plankton volume indicator浮游生物体积测量器plankton counting chamber浮游生物计数框plankton community diversity浮游生物群落多样性plankton community structure浮游生物群落Planktonic foraminifera shell浮游有孔虫壳planktonic foraminiferal zone浮游有孔虫带