Zooplankton of the south-western Atlantic

BOLTOVSKOY DEMETRIO

Johannesburgh and Cape Town, South Africa

Congreso; Fourth National Oceanographic Symposium; 1978

SA

The southern half of the Atlantic Ocean, between the equator and approximately 50° to 55 oS, is one of the most poorly studied ocean areas for several reasons: 1) Most of the older and traditionally more active marine research centres are located far from the South Atlantic. 2) Until a few years ago the area was not considered important from the point of view of its natural resources. However, partly as a result of recent investigations, and partly because of the overexploitation of the richer waters of the northern hemisphere, more and more countries are paying increasing attention to these more oligotrophic but less harvested regions. 3) Much of the information on the biology of the oceans has been gained from studies based on material collected by major oceanographic expeditions, starting with the Challenger. However, very few of these crossed the South-western Atlantic, and the ones that did (e.g. the Challenger, Gazelle, Valdivia, Deutsche Siidpolar and Galathea) collected very few samples in the area. Only the German Meteor expedition collected extensive samples in the South Atlantic, although these included few planktonic taxa. In the mid-fifties, Argentina and, somewhat later, Brazil began organized efforts to explore the South-western Atlantic. Between 1954 and 1974, Argentina carried out more than one hundred cruises in the waters between southern Brazil and Antarctica, which collected thousands of plankton samples. In addition, during the last 15 to 20 years the Soviet Union and, to a lesser extent, the U.S.A. have studied material collected by ships on their way to and from Antarctica.