Show simple item record Garcia, Virginia Maria Tavano Garcia, Carlos Alberto Eiras Mata, Mauricio Magalhães Pollery, Ricardo Cesar Gonçalves Piola, Alberto Ricardo Signorini, Sérgio McClain, Charles Ray Iglesias-Rodriguez, Débora 2012-03-23T23:28:22Z 2012-03-23T23:28:22Z 2008
dc.identifier.citation GARCIA, Virginia Maria Tavano et al. Environmental factors controlling the phytoplankton blooms at the Patagonia shelf-break in spring. Oceanographic Research Papers, v. 55, p. 1150-1166, 2008. Disponível em:<>. Acesso em: 20 mar. 2012. pt_BR
dc.description.abstract The shelf-break front formed between Argentinean shelf waters and the Malvinas Current(MC)flow shows a conspicuous band of high phytoplankton biomass throughout spring and summer, detected by ocean color sensors. That area is the feeding and spawning ground of several commercial species of fish and squid and is thought to play an important role in CO2 sequestration by the ocean. Phytoplankton blooms in this area have been attributed mainly to coccolithophorids, a group of calcite-producing phytoplankton. Here we present the environmental factors associated with the spring bloom at the Patagonian shelf-break (401–481S) in the austral spring 2004. A remarkable bloom of diatoms and dinoflagellates (approximately 1200 km long) was observed along the front, where integrated chlorophyll values ranged from 90.3 to 1074mgm 2. It is suggested that supply of macro-nutrients by upwelling and probably iron by both upwelling and shelf transport contribute to maintaining the spring bloom. Strong water column stability along the front allowed the accumulation of algal cells mainly in the top 50m and their maintenance in the euphotic layer. East of the shelf-break front, macronutrient levels were high (surface nitrate ¼ 16.6 mM, phosphate ¼ 0.35 mM, silicate ¼ 4.0 mM), associated with low phytoplankton biomass (o2mgm 3). This was due to mixing and advection associated with the MC flow and to grazing pressure at a transitional site between the MC and the high chlorophyll patch. Primary production rates (determined by the 14C technique) ranged between 1.9 and 7.8 g Cm 2 d 1. Primary production was highest near 421S partly because of the elevated phytoplankton biomass, which consumed most of the nitrate and phosphate in surface waters in this region. These high primary production rates are comparable with maximal seasonal productivity at eastern boundary currents. The large bloom extent at the Patagonian shelf-break (approximately 55,000km2 patch of 42mgm 3 chlorophyll), the associated primary production rates and diatom dominance indicate a potentially significant biological control of gases such as O2 and CO2 in surface layers. The main factors favoring the development and maintenance of these blooms are nutrient supply from MC upwelling and water column stability. Other processes such as mixing or grazing play an important role in biomass modulation in the region. pt_BR
dc.language.iso eng pt_BR
dc.rights restrict access pt_BR
dc.subject Phytoplankton bloom pt_BR
dc.subject Nutrients pt_BR
dc.subject Primary production pt_BR
dc.subject Patagonia shelf-break pt_BR
dc.subject Malvinas Current pt_BR
dc.title Environmental factors controlling the phytoplankton blooms at the Patagonia shelf-break in spring pt_BR
dc.type article pt_BR
dc.identifier.doi 10.1016/j.dsr.2008.04.011 pt_BR

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