Abstract |
Distribution patterns of planktic foraminifera, collected from Eastern North Atlantic surface waters during August and September 1986, are related to measured hydrographical parameters. Three main water masses, Subpolar Water (SW), the North Atlantic Current (NAC), and the Azores Current (AC) are all characterized by distinct faunal assemblages. A fourth, distinct water mass is here referred to as North Atlantic Transitional Water (NATW). The distinction, based on species clusters, between the NATW and the southern AC, is less evident than between the NATW and the northern SW and the NAC. This is the combined result of low absolute frequencies, a high number of species and a superimposed complex hydrography in the southern water masses. The oceanic frontal zones between the NAC, NATW and the AC coincide with faunal boundaries. Along the boundaries, broad mixing zones can be recognized by their highly diverse foraminiferal assemblages of relatively low equitability. |