scholarly journals DOM fluorescence, a tracer for biogeochemical processes in a coastal upwelling system (NW Iberian Peninsula)

2005 ◽  
Vol 297 ◽  
pp. 33-50 ◽  
Author(s):  
M Nieto-Cid ◽  
XA Álvarez-Salgado ◽  
J Gago ◽  
FF Pérez
Keyword(s):  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Biogeochemical Processes ◽  
Upwelling System

scholarly journals Cycling of dissolved and particulate carbohydrates in a coastal upwelling system (NW Iberian Peninsula)

2004 ◽  
Vol 283 ◽  
pp. 39-54 ◽  
Author(s):  
M Nieto-Cid ◽  
XA Álvarez-Salgado ◽  
S Brea ◽  
FF Pérez
Keyword(s):  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Upwelling System

scholarly journals Life strategies of cephalopod paralarvae in a coastal upwelling system (NW Iberian Peninsula): insights from zooplankton community and spatio-temporal analyses

2016 ◽  
Vol 25 (3) ◽  
pp. 241-258 ◽  
Author(s):  
Álvaro Roura ◽  
X. Antón Álvarez-Salgado ◽  
Ángel F. González ◽  
María Gregori ◽  
Gabriel Rosón ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Zooplankton Community ◽  
Life Strategies ◽  
Upwelling System ◽  
Spatio Temporal

scholarly journals Factors controlling plankton community production, export flux, and particulate matter stoichiometry in the coastal upwelling system off Peru

2020 ◽  
Vol 17 (19) ◽  
pp. 4831-4852
Author(s):  
Lennart Thomas Bach ◽  
Allanah Joy Paul ◽  
Tim Boxhammer ◽  
Elisabeth von der Esch ◽  
Michelle Graco ◽  
...  
Keyword(s):  
Organic Matter ◽  
Coastal Upwelling ◽  
Inorganic Nitrogen ◽  
Abiotic Factors ◽  
Plankton Community ◽  
Light Limitation ◽  
Biogeochemical Processes ◽  
Upwelling System ◽  
Phytoplankton Communities ◽  
Surface Production

Abstract. Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can modify surface production and related biogeochemical processes. Determining these factors is important because EBUS are considered hotspots of climate change, and reliable predictions of their future functioning requires understanding of the mechanisms driving the biogeochemical cycles therein. In this field experiment, we used in situ mesocosms as tools to improve our mechanistic understanding of processes controlling organic matter cycling in the coastal Peruvian upwelling system. Eight mesocosms, each with a volume of ∼55 m3, were deployed for 50 d ∼6 km off Callao (12∘ S) during austral summer 2017, coinciding with a coastal El Niño phase. After mesocosm deployment, we collected subsurface waters at two different locations in the regional oxygen minimum zone (OMZ) and injected these into four mesocosms (mixing ratio ≈1.5 : 1 mesocosm: OMZ water). The focus of this paper is on temporal developments of organic matter production, export, and stoichiometry in the individual mesocosms. The mesocosm phytoplankton communities were initially dominated by diatoms but shifted towards a pronounced dominance of the mixotrophic dinoflagellate (Akashiwo sanguinea) when inorganic nitrogen was exhausted in surface layers. The community shift coincided with a short-term increase in production during the A. sanguinea bloom, which left a pronounced imprint on organic matter C : N : P stoichiometry. However, C, N, and P export fluxes did not increase because A. sanguinea persisted in the water column and did not sink out during the experiment. Accordingly, export fluxes during the study were decoupled from surface production and sustained by the remaining plankton community. Overall, biogeochemical pools and fluxes were surprisingly constant for most of the experiment. We explain this constancy by light limitation through self-shading by phytoplankton and by inorganic nitrogen limitation which constrained phytoplankton growth. Thus, gain and loss processes remained balanced and there were few opportunities for blooms, which represents an event where the system becomes unbalanced. Overall, our mesocosm study revealed some key links between ecological and biogeochemical processes for one of the most economically important regions in the oceans.

Bloom dynamics and life cycle strategies of two toxic dinoflagellates in a coastal upwelling system (NW Iberian Peninsula)

2010 ◽  
Vol 57 (3-4) ◽  
pp. 222-234 ◽  
Author(s):  
Isabel Bravo ◽  
Santiago Fraga ◽  
Rosa Isabel Figueroa ◽  
Yolanda Pazos ◽  
Ana Massanet ◽  
...  
Keyword(s):  
Life Cycle ◽  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Upwelling System ◽  
Toxic Dinoflagellates

scholarly journals Effects of upwelling duration and phytoplankton growth regime on dissolved oxygen levels in an idealized Iberian Peninsula upwelling system

2019 ◽  
Author(s):  
João H. Bettencourt ◽  
Vincent Rossi ◽  
Lionel Renault ◽  
Peter Haynes ◽  
Yves Morel ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Coastal Region ◽  
Phytoplankton Growth ◽  
Biogeochemical Model ◽  
Nutrient Inputs ◽  
Upwelling System ◽  
Growth Regime

Abstract. We apply a coupled modelling system composed of a state-of-the-art hydrodynamical model and a low complexity biogeochemical model to an idealized Iberian Peninsula upwelling system to identify the main drivers of dissolved oxygen variability and to study its response to changes in the duration of the upwelling season and in phytoplankton growth regime. We find that the export of oxygenated waters by upwelling front turbulence is a major sink for nearshore dissolved oxygen. In our simulations of summer upwelling, when phytoplankton population is generally dominated by diatoms whose growth is largely enhanced by nutrient input, net primary production and air-sea exchange compensate dissolved oxygen depletion by offshore export over the shelf. A shorter upwelling duration causes relaxation of upwelling winds and a decrease in offshore export, resulting in a slight increase of net dissolved oxygen enrichment in the coastal region as compared to longer upwelling durations. When phytoplankton is dominated by groups less sensitive to nutrient inputs, growth rates decrease and the coastal region becomes net heterotrophic. Together with the physical sink, this lowers the net oxygenation rate of coastal waters, that remains positive only because of air-sea exchanges. These findings help disentangling the physical and biogeochemical controls of dissolved oxygen in upwelling systems and, together with projections of increased duration of upwelling seasons and phytoplankton community changes, suggest that the Iberian coastal upwelling region may become more vulnerable to hypoxia and deoxygenation.

scholarly journals Effects of upwelling duration and phytoplankton growth regime on dissolved-oxygen levels in an idealized Iberian Peninsula upwelling system

2020 ◽  
Vol 27 (2) ◽  
pp. 277-294
Author(s):  
João H. Bettencourt ◽  
Vincent Rossi ◽  
Lionel Renault ◽  
Peter Haynes ◽  
Yves Morel ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Coastal Region ◽  
Phytoplankton Growth ◽  
Biogeochemical Model ◽  
Nutrient Inputs ◽  
Upwelling System ◽  
Growth Regime

Abstract. We apply a coupled modelling system composed of a state-of-the-art hydrodynamical model and a low-complexity biogeochemical model to an idealized Iberian Peninsula upwelling system to identify the main drivers of dissolved-oxygen variability and to study its response to changes in the duration of the upwelling season and in the phytoplankton growth regime. We find that the export of oxygenated waters by upwelling front turbulence is a major sink for nearshore dissolved oxygen. In our simulations of summer upwelling, when the phytoplankton population is generally dominated by diatoms whose growth is boosted by nutrient input, net primary production and air–sea exchange compensate dissolved-oxygen depletion by offshore export over the shelf. A shorter upwelling duration causes a relaxation of upwelling winds and a decrease in offshore export, resulting in a slight increase of net dissolved-oxygen enrichment in the coastal region as compared to longer upwelling durations. When phytoplankton is dominated by groups less sensitive to nutrient inputs, growth rates decrease, and the coastal region becomes net heterotrophic. Together with the physical sink, this lowers the net oxygenation rate of coastal waters, which remains positive only because of air–sea exchange. These findings help in disentangling the physical and biogeochemical controls of dissolved oxygen in upwelling systems and, together with projections of increased duration of upwelling seasons and phytoplankton community changes, suggest that the Iberian coastal upwelling region may become more vulnerable to hypoxia and deoxygenation.

scholarly journals Particle Fluxes and Bulk Geochemical Characterization of the Cabo Frio Upwelling System in Southeastern Brazil: Sediment Trap Experiments between Spring 2010 and Summer 2012

2014 ◽  
Vol 86 (2) ◽  
pp. 601-620 ◽  
Author(s):  
ANA LUIZA S. ALBUQUERQUE ◽  
ANDRÉ L. BELÉM ◽  
FRANCISCO J.B. ZULUAGA ◽  
LIVIA G.M. CORDEIRO ◽  
URSULA MENDOZA ◽  
...  
Keyword(s):  
Coastal Upwelling ◽  
Cold Water ◽  
Ocean Dynamics ◽  
Southeastern Brazil ◽  
Western Boundary ◽  
Shelf Area ◽  
Biogeochemical Processes ◽  
Upwelling System ◽  
Brazil Current ◽  
Cabo Frio

Physical and biogeochemical processes in continental shelves act synergistically in both transporting and transforming suspended material, and ocean dynamics control the dispersion of particles by the coastal zone and their subsequent mixing and dilution within the shelf area constrained by oceanic boundary currents, followed by their gradual settling in a complex sedimentary scenario. One of these regions is the Cabo Frio Upwelling System located in a significantly productive area of Southeastern Brazil, under the control of the nutrient-poor western boundary Brazil Current but also with a wind-driven coastal upwelling zone, inducing cold-water intrusions of South Atlantic Central Water on the shelf. To understand these synergic interactions among physical and biogeochemical processes in the Cabo Frio shelf, a series of four experiments with a total of 98 discrete samples using sediment traps was performed from November 2010 to March 2012, located on the 145 m isobath on the edge of the continental shelf. The results showed that lateral transport might be relevant in some cases, especially in deep layers, although no clear seasonal cycle was detected. Two main physical-geochemical coupling scenarios were identified: singular downwelling events that can enhance particles fluxes and are potentially related to the Brazil Current oscillations; and events of significant fluxes related to the intrusion of the 18°C isotherm in the euphotic zone. The particulate matter settling in the Cabo Frio shelf area seems to belong to multiple marine and terrestrial sources, in which both Paraiba do Sul River and Guanabara Bay could be potential land-sources, although the particulate material might subject intense transformation (diagenesis) during its trajectory to the shelf edge.

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