El plancton del Atlantico suroeste: dinamica y ecologia

Abstract

Plankton MIaS collected in Nov.·Dec. 1972, during the Cato-6 Expedition (R/V Melvil/e). Distribution 01 SiphQnophores and Medu.§!Jp a'lJi ecologzcal implicatlons pointea out by these organisms are discussea. D sp(U;-!'es vf Siphonopnorae were obtained co"esponding to tropical. temperate, and AntarcticSubantarctic categories. 5 species of Medu sae appeared, showing the peculiar e"atic distribution typical of these organisms.Faunistic data are presented in tables and maps.Effects of Brazil, Falkland Cu"ents and upwelling, c~nters appear well defined by .he distribution of the siphonophores. Cosmopolitan siphonophores, typical of tempera te and warm waters inhabited a band (zone of Rio Crande rise) beJween the $Outhernmost and north(rnmost progressions of Brazil anti Falkland Cu"ents. These populations are C(]TTied to· ward South4merican coasts tJy the anticyclonic circulation of the Central South Atlantic, forming a convergence; anti a divergence towards tlle nprth is responsible for development of upwelling systems