OBSERVATION OF REGENERATION OF NITRATE, PHOSPHATE AND SILICATE DURINGUPWELLING OFF UBATUBA, BRAZIL, 23-DEGREES-S

Off the Brazilian coast near Ubatuba, an upwelling event of South Atla ntic Central Water (SACW) has been observed that transfer nutrient-ric h water from 300 to 400 m depth onto the continental shelf to depths l ess than 35 m. Earlier work showed that SACW is present on the shelf q uite frequently; however, nutrient data as natural tracers of water ma sses, are largely undocumented so far. During the upwelling process th e water advanced over the shelf increasing its nutrients concentration s and depleting its content of dissolved oxygen due to the regeneratio n process. The ratios of regeneration relative to their open ocean ori gin amount to 4.6 mu M for nitrate, 0.43 mu M for phosphate and 5.7 mu M for silicate on average, while the dissolved oxygen depletes by 114 .9 mu M, (C) 1998 Elsevier Science Ltd. All rights reserved.