Science. 1976 Oct 22;194(4263):422-4. doi: 10.1126/science.194.4263.422.
Multivariate cluster analysis of various morphologic indices of Orbulina universa populations from the Indian Ocean indicate the existence of two major groups whose geographic distribution corresponds to the equatorial and central water masses. An abrupt change in shell porosity between populations of this planktonic foraminiferal species in plankton as well as sediment samples occurs within or near the 10 degrees S Hydrochemical Front. Orbulina universa is an excellent indicator of oceanographic conditions in the Indian Ocean today, and may be used as an independent check on shifts in water masses during the last glaciation.
印度洋中具核虫种群的各种形态指数的多元聚类分析表明，存在两个主要群体，其地理分布与赤道和中央水体相对应。在浮游生物和沉积物样本中，这种浮游有孔虫种群的壳孔隙率在南纬 10 度附近或之内发生了急剧变化，该变化位于海洋水化学锋面附近。如今，具核虫是印度洋海洋条件的一个极好指标，并且可以作为对末次冰期期间水团变化的独立检验。
