What controls biological production in coastal upwelling systems? Insights from a comparative modeling study

Verfasser / Beitragende:
[Zouhair Lachkar, Nicolas; id_orcid 0000-0002-2085-2310 Gruber]
Ort, Verlag, Jahr:
2011
Enthalten in:
Biogeosciences, 8 (10), pp. 2961-2976
Format:
Artikel (online)
ID: 528787667
LEADER caa a22 4500
001 528787667
005 20190104030322.0
007 cr unu---uuuuu
008 180924s2011 xx s 000 0 eng
024 7 0 |a 10.3929/ethz-b-000041095  |2 doi 
024 7 0 |a 10.5194/bg-8-2961-2011  |2 doi 
035 |a (ETHRESEARCH)oai:www.research-collecti.ethz.ch:20.500.11850/41095 
100 1 |a Lachkar  |D Zouhair 
245 1 0 |a What controls biological production in coastal upwelling systems? Insights from a comparative modeling study  |h [Elektronische Daten]  |c [Zouhair Lachkar, Nicolas; id_orcid 0000-0002-2085-2310 Gruber] 
506 |a Open access  |2 ethresearch 
520 3 |a The magnitude of net primary production (NPP) in Eastern Boundary Upwelling Systems (EBUS) is traditionally viewed as directly reflecting the wind-driven upwelling intensity. Yet, different EBUS show different sensitivities of NPP to upwelling-favorable winds (Carr and Kearns, 2003). Here, using a comparative modeling study of the California Current System (California CS) and Canary Current System (Canary CS), we show how physical and environmental factors, such as light, temperature and cross-shore circulation modulate the response of NPP to upwelling strength. To this end, we made a series of eddy-resolving simulations of the two upwelling systems using the Regional Oceanic Modeling System (ROMS), coupled to a nitrogen-based Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model. Using identical ecological/biogeochemical parameters, our coupled model simulates a level of NPP in the California CS that is 50 % smaller than that in the Canary CS, in agreement with observationally based estimates. We find this much lower NPP in the California CS despite phytoplankton in this system having nearly 20 % higher nutrient concentrations available to fuel their growth. This conundrum can be explained by: (1) phytoplankton having a faster nutrient-replete growth in the Canary CS relative to the California CS; a consequence of more favorable light and temperature conditions in the Canary CS, and (2) the longer nearshore water residence times in the Canary CS, which permit a larger buildup of biomass in the upwelling zone, thereby enhancing NPP. The longer residence times in the Canary CS appear to be a result of the wider continental shelves and the lower mesoscale activity characterizing this upwelling system. This results in a weaker offshore export of nutrients and organic matter, thereby increasing local nutrient recycling and reducing the spatial decoupling between new and export production in the Canary CS. Our results suggest that climate change-induced perturbations such as upwelling favorable wind intensification might lead to contrasting biological responses in the California CS and the Canary CS, with major implications for the biogeochemical cycles and fisheries in these two ecosystems. 
540 |a Creative Commons Attribution 3.0 Unported  |u http://creativecommons.org/licenses/by/3.0  |2 ethresearch 
700 1 |a Gruber  |D Nicolas; id_orcid 0000-0002-2085-2310  |e joint author 
773 0 |t Biogeosciences  |d Göttingen : Copernicus  |g 8 (10), pp. 2961-2976 
856 4 0 |u http://hdl.handle.net/20.500.11850/41095  |q text/html  |z WWW-Backlink auf das Repository (Open access) 
908 |D 1  |a Journal Article  |2 ethresearch 
950 |B ETHRESEARCH  |P 856  |E 40  |u http://hdl.handle.net/20.500.11850/41095  |q text/html  |z WWW-Backlink auf das Repository (Open access) 
950 |B ETHRESEARCH  |P 100  |E 1-  |a Lachkar  |D Zouhair 
950 |B ETHRESEARCH  |P 700  |E 1-  |a Gruber  |D Nicolas; id_orcid 0000-0002-2085-2310  |e joint author 
950 |B ETHRESEARCH  |P 773  |E 0-  |t Biogeosciences  |d Göttingen : Copernicus  |g 8 (10), pp. 2961-2976 
898 |a BK010053  |b XK010053  |c XK010000 
949 |B ETHRESEARCH  |F ETHRESEARCH  |b ETHRESEARCH  |j Journal Article  |c Open access