Primary production cycle in an upwelling center

MacIsaac, J.J.; Dugdale, Richard C.; Barber, Richard T.; Blasco, Dolors; Packard, Theodore T.

doi:10.1016/0198-0149(85)90042-1

Cited by 140 publications

(83 citation statements)

References 15 publications

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“…Therefore, the low PP rates in Cabo Frio must be mostly due to the lower temperatures. Upwelling systems are generally characterized by cycles of nutrient enrichment and productivity: following the surface increase in nutrients and the water column stabilization by solar heating, an increase in photosynthetic activity and nutrient uptake and, consequently, phytoplankton biomass, occurs (MacIsaac et al 1985, Wilkerson & Dugdale 1987. In Cabo Frio, however, the maximum PP rates registered in the present and previous studies (e.g.…”

Section: Discussioncontrasting

confidence: 54%

Bacterial and Phytoplankton Production in Two Coastal Systems Influenced by Distinct Eutrophication Processes

Guenther¹,

Valentin²

2008

Oeco. Bras.

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Evaluating the relationships between bacterial (BP) and phytoplankton production (PP) is a fi rst step to understand carbon fl uxes through pelagic food webs. In the present study, BP and PP were compared at two tropical coastal systems infl uenced by distinct eutrophication processes in order to assess the main regulating factors of particulate organic carbon (POC) production rates. The waters of Cabo Frio region (23 o 00'S; 42 o 00'W) present high nitrate (N-NO 3 ) levels and low temperatures resulting from the upwelling of deep water masses -thus, a natural eutrophication process -while the waters in Guanabara Bay (22 o 54'S; 43 o 09'W) present high temperatures and levels of dissolved organic carbon (DOC), nitrogen (DON) and nutrients (other than nitrate), resulting from anthropogenic eutrophication, mainly because of sewage wastes. Dissolved organic matter (DOM) elemental composition indicates lower autochthonous contribution in Cabo Frio (C:N ~ 42), probably due to lower phytoplankton production. The elevated temperatures in Guanabara Bay yielded higher PP rates, increasing the phytoplankton contribution to the DOM pool which improved BP. No coupling between BP and PP was observed, and POC production was mainly due to phytoplankton in both systems. Keywords: Guanabara Bay, Cabo Frio, upwelling, carbon cycling. RESUMO PRODUÇÃO BACTERIANA E FITOPLANCTÔNICA EM DOIS SISTEMAS COSTEIROS INFLUENCIADOS POR PROCESSOS DISTINTOS DE EUTROFIZAÇÃO.A avaliação das relações entre produção bacteriana (PB) e fi toplanctônica (PF) consiste em um primeiro passo para o entendimento dos fl uxos de carbono através das teias trófi cas pelágicas. No presente estudo, PB e PF foram comparadas em dois sistemas costeiros tropicais infl uenciados por processos distintos de eutrofi zação a fi m de se estimar os principais fatores reguladores das taxas de produção de carbono orgânico particulado (COP). A região de Cabo Frio (23 o 00'S; 42 o 00'W) apresenta altos teores de nitrato (N-NO 3 ) e baixas temperaturas devido à ressurgência de massas de água profundas -um processo de eutrofi zação natural, enquanto que a Baía de Guanabara (22 o 54'S; 43 o 09'W) apresenta altas temperaturas e altos teores de nutrientes (com exceção do nitrato), carbono e nitrogênio orgânicos dissolvidos (COD e NOD) resultantes de um avançado processo de eutrofi zação antrópica, principalmente através do lançamento de esgotos. A composição elementar da matéria orgânica dissolvida (MOD) indica menor contribuição de fontes autóctones em Cabo Frio (C:N ~ 42), provavelmente devido à menor produção fi toplanctônica. As altas temperaturas na Baía de Guanabara proporcionaram maiores taxas de PF, aumentando a contribuição do fi toplâncton para a MOD como um todo, o que resultou em um incremento da PB. Não foi observado acoplamento entre PB e PF e a produção de COP dos dois sistemas deveu-se principalmente ao fi toplâncton. Palavras-chave: Baía de Guanabara, Cabo Frio, ressurgência, ciclagem de carbono

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Section: Discussioncontrasting

confidence: 54%

Bacterial and Phytoplankton Production in Two Coastal Systems Influenced by Distinct Eutrophication Processes

Guenther¹,

Valentin²

2008

Oeco. Bras.

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“…This is consistent with observations by Abbott et al (1990) in the California upwelling system, who described how the phytoplankton assemblage became progressively dominated by large slow-growing centric diatoms as their drifter moved offshore. In fact, this is the time development of a typical coastal upwelling system (Jones et al, 1993;MacIsaac et al, 1985;Dugdale & Wilkerson, 1989). In contrast, in the filament study NO 3 Ϫ was already depleted in surface waters, phytoplankton numbers were low and were dominated by cells Ͻ2µm, and there was at the deep chlorophyll maximum (DCM).…”

Section: Discussionmentioning

confidence: 69%

“…The small numbers of phytoplankton cells brought to the surface initially have to adapt to the higher light and nutrient conditions (e.g. MacIsaac, Dugdale, Barber, Blasco, & Packard, 1985;Dugdale & Wilkerson, 1989). Covariation between high NO 3 Ϫ and low temperature was still persisting at the intermediate state at which we began the observations, when chlorophyll levels were relatively high, Ͼ0.5mg.m Ϫ3 .…”

Section: Discussionmentioning

confidence: 98%

Off-shelf fluxes of labile materials by an upwelling filament in the NW Iberian Upwelling System

Álvarez-Salgado

Doval

Borges

et al. 2001

Progress in Oceanography

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Daily changes in the concentrations of carbon and nitrogen species were monitored during the course of a Lagrangian drifter experiment in a recurrent upwelling filament south of Cape Finisterre (NW Iberian Upwelling System). A drifting buoy released at the southern edge of the upwelling centre generated by the Cape moved 60km southwestwards from 3 to 7 August 1998. Organic matter in the 50m deep study water mass (average 77±2 µM C) consisted of: 57µM C of dissolved organic matter (DOM) with a C/N molar ratio of 19±2; 6µM C of DOM with a C/N ratio of 9±2, and 14µM C of 50% DOM and 50% suspended organic matter (POM susp ) with a C/N ratio of 6.0±0.4.Net conversion of consumed inorganic salts into accumulated TOM=POM susp +DOM was ෂ40% for nitrogen and ෂ30% for carbon. Since the parcel of water crossed the shelf-edge, these conversion efficiencies are equivalent to net horizontal export-ratio of 0.4 and 0.3 respectively. A second drifter was deployed in the offshore-end of the filament, and was displaced 20km west between 14 and 17 August 1998. Nitrate was exhausted in the surface water and no significant changes were observed in the variables measured during the course of the second experiment. Low C/N ratios (6.5±0.4) and rapid POM susp /DOM inter-conversion in the 20 µM C excess observed in the study volume points to the persistence of the labile materials formed on the shelf during transport to the ocean. Our data demonstrate a) the key role of upwelling filaments in off-shelf export of organic materials and b) the major contribution of DOM to this horizontal export, a previously unaccounted amount.The high nitrogen content of the materials exported make them attractive organic substrates for use by microbial populations in the adjacent oligotrophic ocean. 

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“…During the next 2 months, September-October, after unusually intense and continuous upwelling, recruitment rebounded to values higher than average except for the two stations in the extreme south and north of the measurement region. Barnacles and mussels often show different recruitment patterns (8). Early in the season (May-July), barnacle (Balanus glandula) recruitment was lower than normal at a number of, but not all, sites ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Decreased upwelling can have two effects: reduced nutrient supply to phytoplankton (8) and reduced offshore transport of phytoplankton and planktonic fish and invertebrate larvae that are crucial for replenishing coastal populations (9). Nutrient and phytoplankton reductions may decrease zooplankton (including larvae) survival, and thus decrease recruitment rates of planktotrophic larvae.…”

mentioning

confidence: 99%

Delayed upwelling alters nearshore coastal ocean ecosystems in the northern California current

Barth

Menge

Lubchenco

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

300

267

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Wind-driven coastal ocean upwelling supplies nutrients to the euphotic zone near the coast. Nutrients fuel the growth of phytoplankton, the base of a very productive coastal marine ecosystem [Pauly D, Christensen V (1995) Nature 374:255-257]. Because nutrient supply and phytoplankton biomass in shelf waters are highly sensitive to variation in upwelling-driven circulation, shifts in the timing and strength of upwelling may alter basic nutrient and carbon fluxes through marine food webs. We show how a 1-month delay in the 2005 spring transition to upwelling-favorable wind stress in the northern California Current Large Marine Ecosystem resulted in numerous anomalies: warm water, low nutrient levels, low primary productivity, and an unprecedented low recruitment of rocky intertidal organisms. The delay was associated with 20-to 40-day wind oscillations accompanying a southward shift of the jet stream. Early in the upwelling season (May-July) off Oregon, the cumulative upwelling-favorable wind stress was the lowest in 20 years, nearshore surface waters averaged 2°C warmer than normal, surf-zone chlorophyll-a and nutrients were 50% and 30% less than normal, respectively, and densities of recruits of mussels and barnacles were reduced by 83% and 66%, respectively. Delayed early-season upwelling and stronger late-season upwelling are consistent with predictions of the influence of global warming on coastal upwelling regions.climate variability ͉ coastal marine ecosystems ͉ coastal ocean upwelling ͉ marine ecology E quatorward winds along the eastern boundaries of the world's oceans drive offshore surface Ekman transport and the upwelling of cold, nutrient-rich water into the euphotic zone near the coast. These nutrient pulses stimulate high phytoplankton production, which, in turn, supports a rich coastal marine ecosystem and productive fisheries (1). Examples of such dynamics include the California Current, the Humboldt Current, the Benguela Current, and the Canary Current (2).The strength and extent of the seasonal cycle in upwellingfavorable winds varies along the U.S. west coast. In the northern California Current Large Marine Ecosystem (CCLME), there is a strong seasonal cycle with upwelling-favorable winds, the appearance of cold, saline, nutrient-rich water near the coast, and equatorward currents over the shelf occurring after a spring transition (3). Alongshore winds in the northern CCLME are more variable than those farther south because they are more frequently influenced by eastward-traveling Gulf of Alaska low-pressure systems. The intermittent cessation of upwelling-favorable winds is called relaxation and plays an important role in coastal circulation and the recruitment of marine organisms † † . The timing of the spring transition and the total amount of upwelling-favorable winds during the spring-summer upwelling season have a considerable impact on coastal ecosystem responses. Farther south in the CCLME, winds are more persistently upwelling-favorable and the transition to a more productive spring-su...

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Primary production cycle in an upwelling center

Cited by 140 publications

References 15 publications

Bacterial and Phytoplankton Production in Two Coastal Systems Influenced by Distinct Eutrophication Processes

Bacterial and Phytoplankton Production in Two Coastal Systems Influenced by Distinct Eutrophication Processes

Off-shelf fluxes of labile materials by an upwelling filament in the NW Iberian Upwelling System

Delayed upwelling alters nearshore coastal ocean ecosystems in the northern California current

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