Recent Trends in SST, Chl‐a, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre

Probably not a substantial claim: may not pass S3 (load-bearing).

Decreasing Chl-a concentrations have been recently reported in all five subtropical gyres.

“Decreasing Chl-a concentrations have been recently reported in all five subtropical gyres (Martinez et al., 2020;Signorini et al., 2015;Vantrepotte & Mélin, 2009).”

• cites Martinez et al., 2020 sourcePartly supported

  The 'Reconstruction of Satellite Chl Interannual to Decadal Variability and Trends' section reports generally negative chlorophyll-a trends in the centers of gyres over 1998–2010 and identifies declines in Atlantic and Pacific oligotrophic gyres. It does not establish a decrease in each of the five subtropical gyres, so 'all five' is more specific than the evidence supports. The supplied copy gives no page number for these passages. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites Signorini et al., 2015 sourceDisputed

  The Abstract reports significant downward Chl-a trends in four subtropical gyres, but a weak, statistically insignificant upward trend in the South Pacific gyre. The Summary and Conclusions likewise identifies the South Pacific as the exception, so the paper does not report decreasing Chl-a in all five. (LLM, conf=0.92)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured
• cites Vantrepotte & Mélin, 2009 sourcePartly supported

  The Trend analysis section reports decreasing Chl-a in most subtropical gyre areas, supporting the general pattern. It does not establish a decrease across all five gyres: it also reports an increase in the northern South Atlantic Gyre and opposite trends within some gyre provinces. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

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).”

• cites Betancort et al., 2020 sourcePartly supported

  The Results and Discussion report a long-term decrease in Trade Wind intensity north of the Canary Islands, which supports a narrower wind-decline claim. They also report that intensity increased during the last decade, rather than showing a recent decrease. The paper studies wind at one location and does not establish decreasing Chl-a or NPP across large areas. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites Demarcq, 2009 sourceNot checked — no full text of the source
• cites Gómez-Letona et al., 2017 sourcePartly supported

  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)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

During the last decades, the four major upwelling systems (California, Benguela, Peru, and Canary) have shown an increase in SST.

“During the last decades, the four major upwelling systems (California, Benguela, Peru, and Canary) have shown an increase in SST (Demarcq, 2009;Seabra et al., 2019).”

• cites Demarcq, 2009 sourceNot checked — no full text of the source
• cites Seabra et al., 2019 sourcePartly supported

  The Results report warming in the California, Canary, and Benguela systems over the study period. But the Discussion says Humboldt—the Peru upwelling system—consistently showed a negative SST trend over the last 37 years, so the claim that all four warmed is not supported. (LLM, conf=0.91)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Warming of the surface ocean is expected to increase stratification, resulting in limited vertical exchange with lower layers, reduced nutrient availability in the photic layer, and low primary production rates.

“In general, the warming of the surface ocean is expected to increase stratification resulting in limited vertical exchange with lower layers of the ocean and reduced nutrient availability in the photic layer which, in turn, results in low primary production rates (Behrenfeld et al., 2006;Bonino et al., 2019).”

• cites Behrenfeld et al., 2006 sourceNot checked — no full text of the source
• cites Bonino et al., 2019 sourcePartly supported

  The Introduction (page unavailable) says coastal warming increases stratification and can limit upwelling of nutrient-rich deep water into the euphotic zone. It also says those nutrients sustain phytoplankton blooms. The paper frames this as a possible effect in coastal upwelling systems, not an established ocean-wide reduction in primary production; it notes that changing winds may mitigate or amplify the effect. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Oligotrophic areas in the subtropical gyres are expanding with an accelerating rate.

“Moreover, it has been reported that the oligotrophic areas in the subtropical gyres are expanding with an accelerating rate (Irwin & Oliver, 2009;Meng et al., 2021;Polovina & et al., 2008).”

• cites Irwin & Oliver, 2009 sourceNot checked — no full text of the source
• cites Meng et al., 2021 sourcePartly supported

  Section 3.1 reports that the North Pacific ocean desert expanded from 1998 to 2018 at an average rate of 0.9% per year. It does not report an accelerating expansion rate, and its result concerns the North Pacific rather than subtropical gyres generally. The faster and slower periods discussed in that section refer to oligotrophication, not expansion. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites Polovina & et al., 2008 sourceNot checked — no full text of the source

May combine two claims.

The global upper ocean has warmed during recent decades, and this warming is accompanied by a decrease in chlorophyll-a and productivity.

“The global upper ocean has been warming during the last decades accompanied with a chlorophyll-a (Chl-a) and productivity decrease.”

• Also stated in: § Abstract · plain

  “The global ocean warming signal is accompanied with a decreasing trend in chlorophyll-a (Chl-a) during the last decades (Behrenfeld et al., 2006;Boyce et al., 2010;Signorini et al., 2015;Steinacher et al., 2010).”

• cites Behrenfeld et al., 2006 sourceNot checked — no full text of the source
• cites Boyce et al., 2010 sourceNot checked — no full text of the source
• cites Signorini et al., 2015 sourcePartly supported

  The Abstract and Summary and Conclusions report warming and declining net primary production across five subtropical gyres over 1998–2013. Chlorophyll-a declined in four gyres, but the South Pacific gyre had a weak, statistically insignificant increase. The paper studies these gyres, not the global upper ocean as a whole. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Warming rates of +0.21°C and +0.22°C were found for periods 1970-2009 and 1982-2006, respectively.

“Warming rates of +0.21°C and +0.22°C were found for periods between 1970between -2009between and 1982between -2006between , respectively (Belkin, 2009;;Pardo et al., 2011).”

• cites Belkin, 2009 sourceNot checked — no full text of the source
• cites Pardo et al., 2011 sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Tropicalization of the environment might cause the displacement or substitution of species adapted to the relatively colder waters along the African shelf.

“As a consequence, the tropicalization of the environment might also cause the displacement or substitution of species that are adapted to the relatively colder waters along the African shelf (Verges et al., 2014).”

• cites Verges et al., 2014 sourcePartly supported

  The Introduction (page unavailable) identifies South Africa as a region where tropical fishes have entered temperate waters and proposes that expanding tropical herbivores may cause declines in temperate algae and seagrass. The Conclusion (page unavailable) likewise suggests a broader shift in temperate communities. Our copy does not specifically predict displacement or replacement of cold-water species along the African shelf; the proposed losses concern temperate habitat-forming plants, and the clearest documented impacts are elsewhere. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Pardo et al. (2011) found a higher warming rate from 1970 to 2009 of +0.3°C dec^-1 for the SU.

“On the contrary, Pardo et al. (2011) found a higher warming rate from 1970 to 2009 of +0.3°C dec -1 for the SU.”

• cites Pardo et al. (2011) sourcePartly supported

  Section 2.3 defines the last-four-decades period as 1970–2009. Section 3.2 reports stronger warming in the NW African region during that period, with rates ranging from 0.16 to 0.36°C per decade. This supports warming of roughly the claimed magnitude, but the cited passages do not establish a single +0.3°C-per-decade rate for the SU specifically. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Distribution limits of tropical marine species are believed to shift poleward induced by future warming of the ocean.

“Distribution limits of tropical marine species are believed to shift poleward induced by future warming of the ocean (Verges et al., 2014).”

• cites Verges et al., 2014 sourceSupported

May combine two claims.

Cropper et al. computed the Trade Wind Index, which suggests an intensification of winds since 1973.

“Moreover, they computed the Trade Wind Index (difference of sea level pressure from Azores and Cape Verde) which also suggests an intensification of winds since 1973.”

• cites Cropper et al. (2014) sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Barton et al. conclude no intensification in winds off Northwest Africa.

“They therefore conclude no intensification in winds off Northwest Africa.”

• cites Barton et al. (2013) sourcePartly supported

  The Introduction (p. 3) says evidence that wind velocity is increasing across the Northwest African upwelling region has many uncertainties, and concludes there is no evidence for increasing upwelling intensity. That supports the general direction of the claim, but the stated conclusion concerns upwelling, not specifically an absence of wind intensification. (LLM, conf=0.79)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Barton et al. (2013) underline variations in different data sets and locations, even positive and negative trends for the same location.

“Barton et al. (2013) support this discussion by underlining the variations in different data sets and locations (even positive and negative trends for the same location).”

• cites Barton et al. (2013) sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Betancort et al. (2020) detected a net decrease of up to 1 m s^-1 in wind intensity north of the Canary Islands from 1948 to 2017.

“Similarly, Betancort et al. (2020) detected a net decrease of up to 1 m s -1 in wind intensity north of the Canary Islands from 1948 to 2017 using the same data set.”

• cites Betancort et al. (2020) sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Bonino et al. (2019) pointed out that both wind stress and stratification should be considered in order to evaluate future changes in coastal upwelling.

“Bonino et al. (2019) pointed out that both the wind stress and the stratification should be considered in order to evaluate future changes in coastal upwelling.”

• cites Bonino et al. (2019) sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Pardo et al. (2011) found a wind decrease in Iberia and Northwest Africa which is most prominent from 1970 to 2009.

“Pardo et al. (2011) used the NCEP/NCAR data set and found a wind decrease in Iberia and Northwest Africa which is most prominent from 1970 to 2009.”

• cites Pardo et al. (2011) sourceSupported

May combine two claims.

Warming in coastal areas increases stratification and inhibits vertical nutrient exchange, limiting productivity.

“Warming in coastal areas increases the stratification and inhibits the vertical nutrient exchange limiting the productivity (Brady et al., 2019;Di Lorenzo et al., 2005;Garcia-Reyes et al., 2015).”

• cites Brady et al., 2019 sourcePartly supported

  The Introduction says upwelling brings nutrients to the surface and fuels primary production. The Discussion and conclusions says changes in upper-ocean stratification will affect upwelling, but it does not establish that coastal warming increases stratification or that the resulting changes necessarily inhibit nutrient exchange and limit productivity. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites Di Lorenzo et al., 2005 sourceNot checked — no full text of the source
• cites Garcia-Reyes et al., 2015 sourcePartly supported

  The ‘Water Temperatures and the Counteracting Roles of Upwelling and Stratification’ section says surface warming increases stratification, which can reduce the nutrients brought into the euphotic zone and thereby affect productivity. But the paper discusses this mechanism in eastern boundary upwelling systems and says its productivity effects depend on upwelling winds; it does not establish the claim as an unqualified outcome across coastal areas. No page number is supplied in our copy. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

May combine two claims.

Cropper et al. (2014) and Taboada and Anadón (2012) reported general SST increases in the North Atlantic, with open ocean warming rates in the range of +0.1 to +0.3 °C dec-1.

“Cropper et al. (2014) and Taboada and Anadón (2012) reported general SST increases in the North Atlantic, where warming rates in the open ocean lie in the range of +0.1-0.3°Cdec -1 .”

• cites Cropper et al. (2014) sourcePartly supported

  The ΔSST section reports statistically significant open-ocean warming around parts of the northwest African coast. It does not establish general SST increases across the North Atlantic or give the claimed open-ocean warming range of +0.1 to +0.3 °C per decade. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites Taboada and Anadón (2012) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Changes in wind stress and stratification might be complementary or competitive for upwelling intensity in a global warming scenario.

“Consequently, changes in wind stress and stratification might be complementary or competitive for the upwelling intensity in a global warming scenario (Bachèlery et al., 2016;Pietri et al., 2014).”

• cites Bachèlery et al., 2016 sourceNot checked — no full text of the source
• cites Pietri et al., 2014 sourcePartly supported

  The Discussion and Conclusions (page not provided) link a short-term increase in alongshore wind stress off Peru to changes consistent with wind-driven upwelling. The passages do not address how changes in stratification might complement or compete with wind-stress changes for upwelling intensity under global warming. (LLM, conf=0.79)

  Experimental — accuracy not yet measured

May combine two claims.

Open ocean areas (CI and OA1-3) showed significant NPP trends, generally not as steep as weak permanent upwelling areas, ranging from approximately -30 to -52 mg C m-2 day-1 dec-1 (p<0.05).

“The open ocean areas (CI and OA1-3) show significant trends but generally not as steep as those in the weak permanent upwelling areas, ranging from approximately -30 mg C m -2 day -1 dec -1 to -52 mg C m -2 day -1 dec -1 (p-value < 0.05).”

May combine two claims.

OA1 showed a strong increase in unproductive days at 42 days dec-1, meaning it became unproductive for 84 more days over the last two decades.

“The results for the open ocean areas closely follow the previous findings and highlight the strong increase in unproductive days for OA1 with an increasing rate of 42 days dec -1 .In other words, during the last 2 decades the area OA1 has become unproductive for 84 more days (almost a full season) as compared to 1998.”

• Also stated in: § Abstract · hedged

  “Our results also highlight a significant expansion of the oceanic desert area of 10% with an increase in unproductive days of up to 84 days in the last 20 years.”

May combine two claims.

All upwelling areas show increases in the number of days of upwelling-favorable wind direction in the range of 10-14 days dec^-1, with a larger effect in CJWPU and CGWPU.

“All upwelling areas show increases in the number of days of upwelling-favorable wind direction in the range of 10-14 days dec -1 with a larger effect in the weak permanent upwelling areas (CJWPU and CGWPU).”

May combine two claims.

OA3 decreased in unproductive days in each season, with the most intense decrease in summer at -0.9242 days yr-1 (19 days over 21 years).

“Conversely, OA3 was decreasing in unproductive days (hence increasing in productivity) in each season.The most intense decrease was detected during summer with a yearly rate of -0.9242 days (decrease of 19 days in 21 years).”

May combine two claims.

The productive area in the permanent upwelling areas (PU, CJWPU, and CGWPU) decreased, while the seasonal upwelling area (SU) increased in productive area.

“As seen in the Chl-a trends, the productive area in the permanent upwelling areas (PU, CJWPU, and CGWPU) decreased while in the seasonal upwelling (SU) there was an increase in the area with higher productivity.”

May combine two claims.

All four upwelling areas (PU, CJWPU, CGWPU, and SU) show similar temporal variabilities with positive trends of different intensities.

“All four upwelling areas (PU, CJWPU, CGWPU, and SU) show similar temporal variabilities with positive trends of different intensities.”

May combine two claims.

For the shorter period 1992-2018, warming rates were less intense than over the longer period, but the pattern of more intense warming in the open ocean (OA2 maximum +0.162°C dec-1) and less intense warming in upwelling areas remained.

“The warming rates from 1992 to 2018 are less intense compared to the warming rates evaluated over the longer time period.However, the general feature of more intense warming in the open ocean, with OA2 having the maximum SST increase of 0.162°C dec -1 and less intense warming rates in upwelling areas is still present.”

May combine two claims.

Unproductive days increased in each season in OA1 and OA2, with strongest increases in spring followed by summer.

“The unproductive days were increasing during each season in OA1 and OA2.For both areas we found the strongest increases during spring followed by summer.”

May combine two claims.

Among the upwelling areas, SU showed the fastest warming rate (+0.139°C dec-1), followed by CJWPU (+0.114°C dec-1), while PU and CGWPU had lower warming rates, with CGWPU lowest (+0.066°C dec-1).

“Among the upwelling areas, SU showed the fastest warming ratio, +0.139°C dec -1 , followed by CJWPU with a value of +0.114°C dec -1 .Relatively lower warming rates were found in PU and CGWPU, the latter presenting the lowest SST increase with +0.066°C dec -1 .”

May combine two claims.

The number of days per year when SST rose above the seasonal mean increased in all areas, by 4-10 days dec-1, corresponding to 16-40 more warm days over the last 40 years.

“As expected, all areas exhibited positive rates indicating that the number of days per year when SST values rose above the mean has increased (Table SI1).In fact, all areas show increases in the range of 4-10 days dec -1 meaning that those areas have become warmer for 16-40 days over the last 40 years.”

May combine two claims.

Chl-a trends were statistically significant in the open ocean areas (OA1-3) and in the permanent upwelling areas (PU, CJWPU, and CGWPU).

“Trends were statistically significant (p < 0.05) both in the open ocean areas (OA1-3) and in the permanent upwelling areas (PU, CJW-PU, and CGWPU).”

May combine two claims.

In upwelling areas, the strongest NPP decrease was in CJWPU (-91.99 mg C m-2 day-1 dec-1; p<0.05), followed by CGWPU (-84.38 mg C m-2 day-1 dec-1; p<0.05).

“The strongest trend (-91.99 mg C m -2 day -1 dec -1 ; p-value < 0.05) was detected in CJWPU followed by a slightly less intense decrease in CGWPU (-84.38 mg C m -2 dec -1 ; p-value < 0.05).”

May combine two claims.

In the NASE from 1992 to 2018, positive meridional wind stress trends predominate, especially in coastal areas, although both increases and decreases are present.

“Although both increases and decreases in wind stress are present in the whole NASE, positive trends predominate, especially in coastal areas.”

May combine two claims.

PU productive days decreased in every season, with the most intense decrease in summer at -1.157 days yr-1 (24 days over 21 years).

“Although PU productive days were decreasing during every single season along the time series, the most intense decrease was detected during summer with a yearly rate of -1.157 days (24 days in 21 years).”

May combine two claims.

OA2 exhibits an average warming rate of +0.27°C dec^-1, higher than the trends of the cited authors.

“Although the trends of these authors are generally higher than our results, one of the open ocean areas analyzed in the present study, OA2, exhibits an even higher average warming rate (+0.27°C dec -1 ).”

May combine two claims.

The unproductive areas in CI, OA1, and OA2 were expanding, while OA3 became more productive.

“In close agreement with the evolution of Chl-a concentrations, the unproductive areas in CI, OA1, and OA2 were expanding while OA3 became more productive.”

May combine two claims.

The increase in days above the seasonal mean was lower in upwelling areas (4-6 days dec-1) and higher in open ocean areas (up to 10 days dec-1), and the trends in upwelling areas were statistically non-significant.

“In general, values calculated from this approach reflect the SST warming rates having lower increases in upwelling areas (4-6 days dec -1 ) and higher increases in open ocean areas (up to 10 days dec -1 ).It should be noted that trends in the upwelling areas are statistically non-significant.”

May combine two claims.

The NPP trend in PU was statistically non-significant (p>0.05), while SU and PU showed high p-values compared to other areas.

“It is noteworthy that both SU and PU show high p-values as compared to other areas and the trend of PU is statistically non-significant (p > 0.05).”

May combine two claims.

Open ocean areas OA1-3 presented relatively slower Chl-a trends compared to upwelling areas; Chl-a in OA1 and OA2 slightly declined, while OA3 had a small but significant increase.

“The open ocean areas OA1-3 presented relatively slower trends as compared to the upwelling areas.Whereas Chl-a in OA1 and OA2 is slightly declining, a small but significant increase in photosynthetic biomass was detected in OA3.”

May combine two claims.

OA2 (Azores) showed the maximum SST increase in the NASE, with a rate of +0.269°C dec-1, doubling that observed in CI, OA1, and OA3.

“OA2 showed the maximum SST increase with a rate of +0.269°C dec -1 , doubling that observed in CI, OA1, and OA3 which showed comparable warming rates.”

• Also stated in: § Abstract · plain

  “Our results show significant warming in the area with a maximum of 2.7°C per century for the Azores.”

May combine two claims.

In the upwelling areas, only PU showed a statistically significant trend, with a decrease in productive days of up to 28 days dec-1.

“In the upwelling areas, only the PU shows a trend with statistical significance with a decrease in productive days up to 28 days dec -1 .”

May combine two claims.

Chl-a rates of change in the entire NASE were mostly negative, with a mean value of -0.009 mg m-3 dec-1.

“Chl-a rates of change in the entire NASE were mostly negative and relatively small when observed over the whole analyzed area with a mean value of -0.009 mg m -3 dec -1 .”

May combine two claims.

CJWPU and SU show relatively lower increases, and PU presents the smallest change in wind speed (1.82 mN m^-2 dec^-1).

“CJWPU and SU show relatively lower increases, and PU presents the smallest change in wind speed (1.82 mN m -2 dec -1 ).”

May combine two claims.

Negative Chl-a rates were also detected in CJWPU and CGWPU, though with less intensity than PU.

“Negative rates were also detected in the weak permanent upwelling areas (CJWPU and CGW-PU), though with less intensity.”

May combine two claims.

Most of the studied NASE area presents a decrease in NPP, with a mean average of 37.163 mg C m-2 day-1 dec-1.

“Most of the studied area presents a decrease in NPP, with a mean average of 37.163 mg C m -2 day -1 dec -1 .Still, some pixels with increasing values are present.”

May combine two claims.

The PU has lost about two months of high productivity over the last 21 years and its productive area decreased by 10%.

“Indeed, our results show that the PU has lost about two months of high productivity over the last 21 years and the productive area decreased by 10%.”

• Also stated in: § 5. Conclusions · plain

  “Besides, the permanent upwelling area (PU) has become 60 days more unproductive and the productive area has shrunken by 10% from 1998 to 2018.”

May combine two claims.

The productive area and productive days in the permanent upwelling area are decreasing.

“Similarly, the productive area and productive days in the permanent upwelling area are decreasing.”

May combine two claims.

The results show a general decrease in Chl-a and productivity and an increase in meridional wind.

“Nevertheless, our results show a general decrease in Chl-a and productivity and an increase in meridional wind.”

May combine two claims.

The results indicate meridional wind stress increases and increases in the days when the wind direction was upwelling favorable.

“Our results indicate meridional wind stress increases and increases in the days when the wind direction was upwelling favorable.”

May combine two claims.

OA1 has become up to 87 days more unproductive than in 1998 and its unproductive area has expanded by up to 10%.

“The area has become up to 87 days more unproductive than in 1998 and the unproductive areas has expanded by up to 10%.”

May combine two claims.

Some specific locations in the permanent upwelling areas exhibit cooling trends of up to -1.4°C per century, coinciding with locations where upwelling filaments are characteristic features.

“Interestingly, there are some specific locations in the permanent upwelling areas that exhibit cooling trends of up to -1.4°C per century coinciding with locations where upwelling filaments are characteristic features.”

May combine two claims.

OA3 exhibited a Chl-a increase (+0.04 mg m^-3 dec^-1) accompanied with an increase of productive days up to 22 days during the last 21 years and an expansion of the productive area by +7%.

“Conversely, the open ocean area around Madeira (OA3) exhibited a Chl-a increase (+0.04 mg m -3 dec -1 ) accompanied with an increase of the productive days up to 22 days during the last 21 years together with an expansion of the productive area by a +7%.”

May combine two claims.

OA2 has become 17 days more unproductive and its unproductive area has expanded by approximately 5%.

“The oceanic area around the Azores (OA2) has become 17 days more unproductive and the unproductive area has expanded by approximately 5%.”

May combine two claims.

The overall spatial variability in the NASE from 1982 to 2019 is marked by positive values, with a general warming of +0.201°C dec^-1 (p < 0.05).

“Although the overall spatial variability is clearly marked by positive values in the whole study area (general warming of +0.201°C dec -1 ; p < 0.05), some zones in the permanent upwelling areas (PU and CG-WPU) show remarkable negative trends.”

May combine two claims. The quote only partly states this claim.

The NOAA satellite SST record used in this study was validated against independent in-situ data, with statistically significant slope coefficients of 0.8412 for open ocean and 0.6186 for upwelling areas.

“The slope coefficients of the linear regression of both areas are statistically significative (0.8412 and 0.6186, respectively), allowing us to proceed using satellite data on the analysis (Figures SI1 and SI2).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Chl-a satellite data could not be validated with in situ data from the RaProCan cruise because no Chl-a samples were available.

“Chl-a satellite data could not be validated with in situ-data of the RaProCan cruise since no Chl-a samples were available.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The difference in warming intensity is probably due to the different length in time periods.

“This difference in intensity is probably due to the different length in time periods.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The wind direction was almost exclusively equatorward around the whole year in the permanent upwelling areas and from April to October in the seasonal upwelling area.

“The wind direction was almost exclusively equatorward around the whole year in the permanent upwelling areas and from April to October in the seasonal upwelling area (Wooster et al., 1976).”

• cites Wooster et al., 1976Not checked — no full text of the source

May combine two claims.

Natural interannual and interdecadal climate variability plays an important role in the magnitude of trends and can influence the signal of relatively short time periods.

“Natural interannual and interdecadal climate variability (e.g., induced by oscillations such as the Atlantic-Multidecadal Oscillation (AMO) or the North Atlantic Oscillation (NAO)) play an important role in the magnitude of trends and can influence the signal of relatively short time periods (Polonsky & Serebrennikov, 2018).”

• cites Polonsky & Serebrennikov, 2018Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Sambe et al. (2016) found a net warming of the Canary upwelling system and that the SST increase in the Canary upwelling system is the strongest among the four EBUS.

“Sambe et al. (2016) found a net warming of the Canary upwelling system and highlight that out of all four EBUS the SST increase in the Canary upwelling system is the strongest one.”

• cites Sambe et al. (2016) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

The Polonsky and Serebrennikov result reflects the findings of this study.

“This result reflects the findings of our study.”

Classified as probably not a substantial claim.

If the time period selected for the data set is too short, a false signal may be evidenced.

“If the time period selected for the data set is too short, a false signal may be evidenced.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The Chl-a and NPP data sets are independent and extracted from two different sources.

“It should also be noted that although Chl-a and NPP trends are discussed in one section, both data sets are independent and extracted from two different sources.”

May combine two claims.

The SST increases in the three permanent upwelling areas vary slightly from the rate Polonsky and Serebrennikov found but are in good agreement with their trend as an average value.

“The SST increases in the three permanent upwelling areas vary slightly from the rate they found but are in good agreement with their trend as an average value.”

May combine two claims.

The values of NPP and Chl-a from Signorini et al. are 2-3 times lower than this study's findings but are still consistent with the decreases in NPP and Chl-a found for the open ocean.

“Although the values of NPP and Chl-a are 2-3 times lower than our findings, they are still consistent with the decreases in both NPP and Chl-a that we found for the open ocean.”

May combine two claims.

The results imply that these changes are already occurring, leading to decreases in both Chl-a and NPP and the expansion of the most oligotrophic areas.

“Our results imply that these changes are already occurring leading to the decreases in both Chl-a and NPP and the expansion of the most oligotrophic areas.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Behrenfeld et al. suggested that enhanced stratification in a warming context suppresses nutrient exchange and productivity due to reduced vertical mixing.

“These authors suggested that enhanced stratification in a warming context suppresses nutrient exchange and productivity due to reduced vertical mixing.”

• cites Behrenfeld et al. (2006) sourceNot checked — no full text of the source

May combine two claims.

The SST increase in the Macaronesian Islands has resulted in the arrival of thermophilic species of tropical origin and the geographic expansion of endemic thermophilic species around several islands.

“The SST increase in the region of the Macaronesian Islands has already resulted both in the arrival of thermophilic species of tropical origin and the geographic expansion of endemic thermophilic species around several islands (Afonso et al., 2013;Brito et al., 2014Brito et al., , 2017)).”

• cites Afonso et al., 2013 sourceNot checked — no full text of the source
• cites Brito et al., 2014Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Brito et al., 2017Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Polovina et al. (2008) found supporting evidence of decreasing Chl-a concentrations and an expansion of oligotrophic waters.

“Polovina et al. (2008) analyzed the temporal and spatial evolution of the most oligotrophic areas in the subtropical gyres and found supporting evidence of decreasing Chl-a concentrations and an expansion of oligotrophic waters.”

• cites Polovina et al. (2008) sourceNot checked — no full text of the source

May combine two claims.

Santos et al. (2012) found a warming trend in the permanent upwelling area from 1982 to 2010 that increases southward, with some specific areas showing surface cooling.

“Santos et al. (2012) analyzed SST from 1982 to 2010 in the permanent upwelling area and found a warming trend which is increasing southward, noting that some specific areas show surface cooling.”

• cites Santos et al. (2012) sourceNot checked — no full text of the source

May combine two claims.

The decreases found for Chl-a are more intense than those in the literature, although the negative trends are generally in good agreement with this study's results.

“Although the negative trends are generally in good agreement with our results, the decreases we found for Chl-a are more intense.”

May combine two claims.

Vantrepotte and Mélin (2009, 2011) found a global increase in Chl-a for different time periods but Chl-a decreases in all five gyres during the time period they analyzed.

“Vantrepotte and Mélin (2009, 2011) found a global increase in Chl-a for different time periods but Chl-a decreases in all five gyres during the time period Vantrepotte and Mélin (2009, 2011) analyzed.”

• cites Vantrepotte and Mélin (2009, 2011)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Gregg and Conkright (2002) identified that global Chl-a means were decreasing.

“Gregg and Conkright (2002) compared global Chl-a variation from 1979to 1986 (CZCS) and from 1997 to 2000 (SeaWiFS).They identified that global Chl-a means were decreasing.”

• cites Gregg and Conkright (2002) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

The differences in warming rates in open ocean and upwelling areas and localized cooling trends might indicate an upwelling intensification.

“The differences in warming rates in open ocean and upwelling areas and localized cooling trends might indicate an upwelling intensification as the coastal waters are less warmed due to the cooler upwelled waters (Polonsky & Serebrennikov, 2018).”

• cites Polonsky & Serebrennikov, 2018Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Polovina et al. and Signorini et al. analyzed the oligotrophic area in the whole subtropical gyre whereas this study focused on the eastern part.

“It should be noted however, that Polovina et al. (2008) and Signorini et al. (2015) analyzed the oligotrophic area in the whole subtropical gyre whereas we focused on the eastern part.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Ould-Dedah et al. (1999) observed cooling trends in the permanent upwelling area, though they analyzed a different time period.

“Such cooling trends in the permanent upwelling area had already been observed in 1999 by Ould-Dedah et al. (1999), though it has to be noted that they analyzed a different time period .”

• cites Ould-Dedah et al. (1999) sourceNot checked — no full text of the source

May combine two claims.

If the SST trend continues, it might facilitate future tropicalization and enable the arrival of other tropical species and the population increase of native thermophilic species.

“If the SST trend continues it might facilitate future tropicalization and enable the arrival of other tropical species and the population increase of native thermophilic species (Brito et al., 2017).”

• cites Brito et al., 2017Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The NPP trends from Gómez-Letona et al. were exclusively negative as in this study's results, although this study's values are generally smaller.

“The NPP (CbPm, MODIS) trends, however, were exclusively negative as in our results, although our values are generally smaller.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Polovina et al. detected that the oligotrophic area in the North Atlantic subtropical gyre appeared to be expanding most rapidly (4.3% yr^-1).

“Indeed, the authors detected that the oligotrophic area in the North Atlantic subtropical gyre appeared to be expanding most rapidly (4.3% yr -1 ).”

• cites Polovina et al. (2008) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S4 (based).

An upwelling intensification would result in an increase in productivity and surface Chl-a.

“An upwelling intensification would also result in an increase in productivity and surface Chl-a.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The most oligotrophic areas of the North Atlantic subtropical gyre are located rather in the western part of the North Atlantic due to its asymmetry.

“In fact, the most oligotrophic areas of the North Atlantic subtropical gyre are located rather in the western part of the North Atlantic due to its asymmetry (Munk & Carrier, 1950).”

• cites Munk & Carrier, 1950 sourceNot checked — no full text of the source

May combine two claims.

Baptista et al. (2017) found a positive SST trend in the range of +0.1-0.2°C dec^-1 off Iberia over the last 60 years, in good agreement with this study.

“Baptista et al. (2017) analyzed SST variability off Iberia over the last 60 years.The authors found a positive trend in the range of +0.1-0.2°Cdec -1 which is in good agreement with the results from our study.”

• cites Baptista et al. (2017)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

These increases are in alignment with previously published studies and especially the upwelling intensification hypothesis.

“These increases are in alignment with previously published studies and especially the upwelling intensification hypothesis (Table 4).”

• cites Table 4Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing). May combine two claims.

Consequently, the temperature difference at land and sea would cause greater pressure gradients leading to intensified alongshore winds and enhanced upwelling.

“Consequently, the temperature difference at land and sea would cause greater pressure gradients leading to intensified alongshore winds and enhanced upwelling.”

• cites Bakun (1990) sourceNot checked — no full text of the source

May combine two claims.

The general warming in upwelling areas contrasts with Bakun's hypothesis but is consistent with the decreasing productivity.

“Furthermore, the general warming in upwelling areas contrasts with Bakun's hypothesis but is consistent with the decreasing productivity.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Narayan et al. argue that the less reliable results derive from the NCEP/NCAR data.

“In addition, they argue that the less reliable results derive from the NCEP/NCAR data.”

• cites Narayan et al. (2010) sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Santos et al. (2005) detected decadal shifts in upwelling intensity in the Canary upwelling system from 1982 to 2001.

“Santos et al. (2005) analyzed the Canary upwelling system from 1982 to 2001 and detected decadal shifts in the upwelling intensity.”

• cites Santos et al. (2005) sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Bakun (1990) hypothesized that upwelling favorable winds would intensify under global warming.

“In 1990, Bakun (1990) hypothesized that the upwelling favorable winds would intensify under global warming.”

• cites Bakun (1990) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Bakun hypothesized that a global warming scenario with increased CO2 concentrations would reduce night-time cooling and increase daytime warming.

“In fact, the author hypothesized that a global warming scenario with increased CO 2 concentrations would reduce night-time cooling and increase daytime warming.”

• cites Bakun (1990) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

It was proposed that upwelling in EBUS will be increasing during future global warming scenarios.

“It was therefore proposed that upwelling in EBUS will be increasing during future global warming scenarios.”

• cites Bakun (1990) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

As suggested by Santos et al. (2005), one would expect a productivity increase in relation to strengthened upwelling-favorable wind stress intensity.

“As suggested by Santos et al. (2005) we would expect a productivity increase in relation to strengthened upwelling-favorable wind stress intensity.”

• cites Santos et al. (2005) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Some authors have evidenced negative wind trends for similar time periods, in contrast to this study's results.

“In contrast to our results, some authors have also evidenced negative wind trends for similar time periods.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The Bakun hypothesis initiated from the fact that trade winds in all four EBUS had increased from the mid-1900s to the 1980s.

“Briefly, the Bakun hypothesis initiated from the fact that trade winds in all four EBUS (Canary, California, Peru, and Benguela) had increased from the mid-1900s to the 1980s.”

• cites Bakun (1990) sourceNot checked — no full text of the source

May combine two claims.

In the last decades, pelagic fish stocks have been observed to be declining, which might be associated with the decreasing Chl-a and productivity trends.

“In the last decades, pelagic fish stocks have already been observed to be declining (Sardine, Sardinella) which might be associated to the decreasing Chl-a and productivity trends (Sambe et al., 2016).”

• cites Sambe et al., 2016 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Narayan et al. (2010) concluded that COADS data provided the most reliable results of significant increases in meridional wind stress in all four EBUS.

“Narayan et al. (2010) detected differences between data sets and concluded that COADS data provided the most reliable results of significant increases in meridional wind stress in all four EBUS (in CCU from 28.5 to 33.5°N).”

• cites Narayan et al. (2010) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Santos et al. found that variability in wind forcing provides reasonable explanations for the shifts in upwelling intensity and their timing.

“They found that the variability in wind forcing provides reasonable explanations for the shifts in upwelling intensity and their timing.”

• cites Santos et al. (2005) sourceNot checked — no full text of the source

May combine two claims.

The findings both support and contradict Bakun's hypothesis.

“Moreover, our findings both support and contradict Bakun's hypothesis.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Smith et al. (2001) showed that the NCEP/NCAR reanalysis data underestimate the global wind intensity.

“Smith et al. (2001) showed that the NCEP/NCAR reanalysis data underestimate the global wind intensity.”

• cites Smith et al. (2001)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Narayan et al. suggested that the underestimation of the wind strength might be the reason for the negative trends.

“Narayan et al. (2010) consequently suggested that the underestimation of the wind strength might be the reason for the negative trends.”

• cites Narayan et al. (2010) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

The Canary upwelling system is a highly valuable large marine ecosystem providing ecosystem services with an estimated amount of US$ 11.7 billion.

“The Canary upwelling system is a highly valuable large marine ecosystem providing ecosystem services with an estimated amount of US$ 11.7 billion (Interwies & Görlitz, 2013).”

• cites Interwies & Görlitz, 2013Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Several authors have found increases in the meridional wind stress in agreement with this study's results.

“Several authors have indeed found increases in the meridional wind stress in agreement with our results.”

May combine two claims.

The results add more evidence to the forecasted decline in pelagic fish stocks that might affect the resources of millions of people depending on fisheries in the Canary upwelling system.

“Our results add more evidence to the forecasted decline in pelagic fish stocks that eventually might affect the resources of millions of people that depend on the fisheries activities in the Canary upwelling system.”

• AssumptionRests on an assumption: Pelagic fish species are sensitive to changes in environmental forcing and the state of the environment.

The quote only partly states this claim.

The pattern of meridional wind trends and the intensity of the trends (up to 0.5 m s-1 dec-1) from MERRA, 20CR, CFSR, NCEP-DOE II, and ERA-I reanalysis from 1981 to 2012 are consistent with our results.

“The pattern of meridional wind trends and the intensity of the trends (up to 0.5 m s -1 dec -1 ) are consistent with our results.”

• cites MERRANot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites 20CRNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites CFSRNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

These results support Bakun's hypothesis as enhanced upwelling forced by increasing winds would lead to a cooling of surface waters and an increase in productivity.

“These results would support Bakun's hypothesis as enhanced upwelling forced by increasing winds would lead to a cooling of surface waters and an increase in productivity.”

May combine two claims.

The increase in meridional wind stress agrees with Bakun's upwelling intensification hypothesis but contrasts with decreases in Chl-a and NPP in upwelling areas.

“Although the increase in meridional wind stress is in agreement with Bakun's upwelling intensification hypothesis, it contrasts with decreases in Chl-a and NPP in upwelling areas.”

May combine two claims.

Both stratification and coastal trapped waves may reduce productivity by limiting vertical exchange of nutrients to the surface.

“Both stratification and coastal trapped waves may reduce the productivity by limiting vertical exchange of nutrients to the surface.”

May combine two claims.

These results emphasize the complex interplay of wind stress and stratification in upwelling areas and their competitive or complementary consequences, which will be especially important in future climate change conditions.

“These results emphasize even more the complex interplay of wind stress and stratification in upwelling areas and their competitive or complementary consequences which will be especially important in future climate change conditions.”

May combine two claims.

Polonsky and Serebrennikov (2018) examined wind intensity (modulus and both zonal and meridional wind components) in Northwest Africa during the last 30 years and showed an increase in wind intensity for the modulus and both the meridional and zonal components.

“Polonsky and Serebrennikov (2018) examined the wind intensity (modulus and both zonal and meridional wind components) in Northwest Africa during the last 30 years, also showing an increase in wind intensity for the modulus and both the meridional and zonal components.”

• cites Polonsky and Serebrennikov (2018)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Increasing trends in meridional wind stress intensity and upwelling favorable wind direction lead to contradictory conclusions.

“Increasing trends in the meridional wind stress intensity and the upwelling favorable wind direction (around 40 days more upwelling favorable from 1992 to 2018) lead to contradictory conclusions.”

May combine two claims.

Warming appears better aligned with decreases in Chl-a, productivity, expansion of unproductive areas, and decrease of productive area than with increases in meridional wind stress and upwelling favorable wind direction days.

“The warming in the open ocean and upwelling areas, however, appears to be in better alignment with the decreases in Chl-a, productivity, the expansion of unproductive areas in the open ocean and the decrease of productive area in the upwelling region than the increases in meridional wind stress and upwelling favorable wind direction days.”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

This relationship may be either complementary or competitive.

“This relationship may be either complementary or competitive.”