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Cited by 57Marine and coastal ecosystemsOceanographic and Atmospheric ProcessesMarine and fisheries research

Trends in Primary Production in the Canary Current Upwelling System—A Regional Perspective Comparing Remote Sensing Models

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Gómez-Letona, Markel, Ramos, Antonio G., Coca, Josep, Arístegui, Javier·2017·Frontiers in Marine Science
DOI 10.3389/fmars.2017.00370
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Abstract

After Andrew (Bakun, 1990) formulated his hypothesis of upwelling intensification caused by increasing global warming, contradictory results have been published on whether primary productivity is increasing or decreasing in Eastern Boundary Upwelling Ecosystems (EBUE). The present work is focused in comparing three net primary production (NPP) models -the VGPM (Vertically Generalized Production Model), the Eppley-VGPM and the CbPM (Carbon-based Production Model)- in the Canary Current (CanC) EBUE during the 1998-2015 period, making use of both SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MODIS (MODerate-resolution Imaging Spectroradiometer) derived data. We looked for the first time for seasonal to interannual trends of NPP under a regional perspective, with the aim of searching for temporal patterns that could support or reject the intensification hypothesis. According to previous studies based on the seasonality of the upwelling regime, the CanC EBUE was divided into three subregions: a seasonal upwelling zone (SUZ; 13-20ºN), a permanent upwelling zone (PUZ; 20-26ºN) and a weak permanent upwelling zone (WPUZ; 26-33ºN). Our analyses do not show significant increasing trends in NPP with any of the productivity models used, challenging Bakun’s hypothesis. Nevertheless, differences in the output of the models are important, both at regional and subregional scales, questioning the accuracy of the models. The comparison made in this work clearly shows the disagreements between some of the best-known NPP models and calls for a validation effort in this region. Contrary to the open-ocean, temperature trends show significant decreases in certain areas over the shelf waters, which might indicate an increase of cool, upwelled waters in those regions. Seasonal to decadal anomalies of NPP and sea-surface temperature (SST) are estimated and analyzed in relation to selected climate indices, yielding only significant correlations between SST and the North Atlantic Oscillation (NAO) indices.

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  • MODIS CbPm provided NPP trends with the highest statistical significance in the Canary upwelling system.

    “For this work, MODIS data were used since according to Gomez-Letona et al. (2017) MODIS CbPm provided NPP trends with the highest statistical significance in the Canary upwelling system.”

    From Recent Trends in SST, Chl‐<i>a</i>, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre (2021) · cites this paper as Gomez-Letona et al. (2017)

    The Trends in NPP and Chl-a section says the MODIS dataset shows very weak trends, while SeaWiFS CbPM shows marked, statistically significant decreases. It also says CbPM trends become gentler with MODIS, contrary to the claim that MODIS CbPM provided the trends with the highest statistical significance. Page numbers are not available in our copy. (LLM, conf=0.88)

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  • Subtropical gyres and Eastern Boundary Upwelling Systems exhibit different spatial and temporal trends in SST, Chl-a, NPP, and meridional wind.

    “Specific oceanographic areas such as the subtropical gyres and the Eastern Boundary Upwelling Systems (EBUS) exhibit different spatial and temporal trends in SST, Chl-a, NPP, and meridional wind (Demarcq, 2009;Gómez-Letona et al., 2017;Polonsky & Serebrennikov, 2018;Polovina et al., 2008).”

    From Recent Trends in SST, Chl‐<i>a</i>, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre (2021) · cites this paper as Gómez-Letona et al., 2017

    The Trends in SST and Trends in NPP and Chl-a sections report spatial and temporal differences within the Canary Current upwelling system. The paper also discusses meridional-wind findings from other studies, but it does not establish the claimed comparison between subtropical gyres and Eastern Boundary Upwelling Systems across all four variables. Page numbers are unavailable in our copy. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • While increasing Chl-a concentrations have been observed in most EBUS, large areas in the Canary upwelling system showed recent decreasing trends in Chl-a, NPP, and meridional wind.

    “However, while increasing concentrations of Chl-a have been observed in most EBUS, large areas in the Canary upwelling system showed recent decreasing trends in Chl-a, NPP (based on ocean color models) and meridional wind (Betancort et al., 2020;Demarcq, 2009;Gómez-Letona et al., 2017).”

    From Recent Trends in SST, Chl‐<i>a</i>, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre (2021) · cites this paper as Gómez-Letona et al., 2017

    The ‘Trends in NPP and Chl-a’ section reports decreasing Chl-a and model-derived NPP in substantial parts of the Canary system, but emphasizes that the trends vary by dataset, model, and subregion. The paper describes Canary upwelling winds as weakened or not intensified, but does not establish the claimed recent decrease in meridional wind across large areas. Its Introduction also describes evidence across upwelling systems as contradictory, rather than establishing increasing Chl-a in most of them. The indexed passages provide section labels but no page numbers. (LLM, conf=0.86)

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  • Gómez-Letona et al. demonstrate that the areas of cooling are situated at coastal locations where upwelling filaments are common features.

    “They further demonstrate that these areas of cooling are situated at coastal locations where upwelling filaments are common features.”

    From Recent Trends in SST, Chl‐<i>a</i>, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre (2021) · cites this paper as Gómez-Letona et al. (2017)

    The Trends in SST section (page unavailable) places slightly negative temperature trends at coastal upwelling cores, including Cape Ghir. The Study Area section (page unavailable) identifies Cape Ghir as a cape where recurrent filaments form. The copy does not establish that filaments are common at every cooling location the paper identifies. (LLM, conf=0.81)

    Experimental — accuracy not yet measured

  • Several authors found that the Canary upwelling system has decreased in productivity and Chl-a over the last 20 years.

    “Several authors found that the Canary upwelling system has decreased in productivity and Chl-a over the last 20 years (Aristegui et al., 2009;Demarcq, 2009;Gomez-Letona et al., 2017;Sambe et al., 2016).”

    From Recent Trends in SST, Chl‐<i>a</i>, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre (2021) · cites this paper as Gomez-Letona et al., 2017

    The Introduction reports a decrease in chlorophyll over the last two decades. But the Trends in NPP and Chl-a section and Conclusions describe heterogeneous results: depending on the dataset, model and upwelling zone, productivity and Chl-a showed significant decreases or no significant change. They do not establish a system-wide decline in both measures over that period. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

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Cites

  • Global surface temperature change

    Hansen, J., Ruedy, R., Sato, M., & Lo, K. (2010) · Reviews of Geophysics · doi:10.1029/2010rg000345 · Cited by 3,081 · cited 2× · see citing works

    “Over recent decades increasing trends in global warming have been evident in most oceanic regions, both at surface and deep layers (Levitus et al., 2000, 2005; Gille, 2002; Ihara et al., 2008; Hansen et al., 2010; Gouretski et al., 2012; Nieves et al., 2015).”
    Background

  • Canary current upwelling: More or less?

    Barton, E. D., Field, D. B., & Roy, C. (2013) · Progress in Oceanography · doi:10.1016/j.pocean.2013.07.007 · Cited by 134 · cited 11× · see citing works

    “The present work aims to shed some light on this controversy by analyzing spatiotemporal trends on physical and biological variables in the Canary Current (CanC) upwelling region, which is located along the northwestern African coast (Figure 1) and constitutes one of the four major EBUEs in the planet, along with the…”
    BackgroundResultInfluential

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Cited by

Sorted by citations

Authors
Gómez-Letona, M., Ramos, A. G., Coca, J., & Arístegui, J.
Affiliations
Universidad de Las Palmas de Gran Canaria (ES)
ORCID
Venue
Frontiers in Marine Science
Publisher
Frontiers Media SA
Published
2017-11-14
Volume
4
ISSN
2296-7745 (ISSN-L)
DOI
10.3389/fmars.2017.00370
OpenAlex
W2769779142
Cited by
57
References
2
Citations by year
2026: 2 · 2025: 9 · 2024: 7 · 2023: 6 · 2022: 6 · 2021: 13 · 2020: 10 · 2019: 4
FWCI
2.54
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Frontiers in Marine Science (publishedVersion, cc-by)
  • Acceda (Universidad de Las Palmas de Gran Canaria) (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Marine and coastal ecosystems
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Oceanographic and Atmospheric Processes
  • Physical Sciences › Environmental Science › Global and Planetary Change › Marine and fisheries research
Keywords
net primary productivity, Canary Current, SeaWiFS, MODIS, interannual variability, sea surface temperature, North Atlantic Oscillation, shelf waters

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