Trends of the Galician upwelling in the context of climate change

Casabella, N.; Lorenzo, Nieves; Taboada, J. J.

doi:10.1016/j.seares.2014.01.013

Cited by 33 publications

(30 citation statements)

References 17 publications

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“…However, several authors recognised a contemporary trend for a decrease in intense upwelling events and increased downwelling periods (Portuguese coast [80], Galicia [81] and California [82]). Such a global decrease in frequency and intensity of coastal upwelling events may have important socio-economic consequences [11] both by the decline of fisheries and by increasing the frequency of HAB.…”

Section: Discussionmentioning

confidence: 99%

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

et al. 2017

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From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceanographic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer- (inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change.

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Section: Discussionmentioning

confidence: 99%

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

et al. 2017

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“…Projections for the Humboldt Goubanova et al, 2011;Echevin et al, 2012;Belmadani et al, 2014;Rykaczewski et al, 2015;Wang et al, 2015), Benguela (Jury and Courtney, 1995;Rykaczewski et al, 2015;Wang et al, 2015), and Iberian Systems suggest future intensification of upwelling winds Casabella et al, 2014;Lopes et al, 2014;Rykaczewski et al, 2015;Wang et al, 2015). In contrast, the California System projections show non-significant or decreasing trends (Mote and Salathé, 2010;Rykaczewski et al, 2015;Wang et al, 2015).…”

Section: Trends In Upwelling-favorable Windsmentioning

confidence: 98%

“…The variability in trends derived from global-scale models may be due either to their relatively coarse resolution, which precludes adequate representation of smaller-scale coastal processes, including upwelling Casabella et al, 2014), or to their failure to adequately incorporate processes relevant to upwelling, e.g., cloud cover, inversion-layer height (Winant et al, 1988), or land-ocean pressure gradients. Downscaling global models to the coastal domain of EBUS is required to address some of these issues.…”

Section: Trends In Upwelling-favorable Windsmentioning

confidence: 99%

Under Pressure: Climate Change, Upwelling, and Eastern Boundary Upwelling Ecosystems

et al. 2015

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The IPCC AR5 provided an overview of the likely effects of climate change on Eastern Boundary Upwelling Systems (EBUS), stimulating increased interest in research examining the issue. We use these recent studies to develop a new synthesis describing climate change impacts on EBUS. We find that model and observational data suggest coastal upwelling-favorable winds in poleward portions of EBUS have intensified and will continue to do so in the future. Although evidence is weak in data that are presently available, future projections show that this pattern might be driven by changes in the positioning of the oceanic high-pressure systems rather than by deepening of the continental low-pressure systems, as previously proposed. There is low confidence regarding the future effects of climate change on coastal temperatures and biogeochemistry due to uncertainty in the countervailing responses to increasing upwelling and coastal warming, the latter of which could increase thermal stratification and render upwelling less effective in lifting nutrient-rich deep waters into the photic zone. Although predictions of ecosystem responses are uncertain, EBUS experience considerable natural variability and may be inherently resilient. However, multi-trophic level, end-to-end (i.e., "winds to whales") studies are needed to resolve the resilience of EBUS to climate change, especially their response to long-term trends or extremes that exceed pre-industrial ranges.

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“…For example, [Bakun (1990), Casabella et al (2014), Lorenzo et al (2005), Ramos et al (2013)] reported an enhancement of favourable conditions for upwelling in recent years but, in contrast, other authors report a weakening in the number and intensity of upwelling events with climate alterations [Alvarez et al (2008), Álvarez Salgado et al (2008), Alves and Miranda (2012), Lemos and Pires (2004), Lemos and Sansó (2006)]. …”

Section: Sagres Regionmentioning

confidence: 99%

Time series analysis of data for sea surface temperature and upwelling components from the southwest coast of Portugal

Goela

Cordeiro

Danchenko

et al. 2016

Journal of Marine Systems

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Time series analysis of data for sea surface temperature and upwelling components from the southwest coast of AbstractThis study relates sea surface temperature (SST) to the upwelling conditions off the southwest coast of Portugal using statistical analyses of publically available data.Optimum Interpolation (OI) daily SST data were extracted from the United States (US) National Oceanic and Atmospheric Administration (NOAA) and data for wind speed and direction were from the US National Climatic Data Center. Time series were extracted at a daily frequency for a time horizon of 26 years. Upwelling indices were estimated using westerly (Q x ) and southerly (Q y ) Ekman transport components.In the first part of the study, time series were inspected for trend and seasonality over the whole period. The seasonally adjusted time series revealed an increasing slope for SST (0.15ºC per decade) and decreasing slopes for Q x (-84.01 m 3 .s -1 .km -1 per decade) and Q y (-25.20 m 3 .s -1 .km -1 per decade), over the time horizon. Structural breaks analysis applied to the time series showed that a statistically significant incremental increase in SST was more pronounced during the last decade. Cross-correlation between upwelling indices and SST revealed a time delay of 5 and 2 days between Q x and SST, and between Q y and SST, respectively. A spectral analysis combined with the previous analysis enabled the identification of four oceanographic seasons. Those seasons were later recognised over a restricted time period of 4 years, between 2008 and 2012; when there was an extensive sampling programme for the validation of ocean colour remote sensing imagery. The seasons were defined as: summer, with intense and regular events of upwelling; autumn, indicating relaxation of upwelling conditions; and spring and winter, showing high interannual variability in terms of number and intensity of upwelling events.

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Trends of the Galician upwelling in the context of climate change

Cited by 33 publications

References 17 publications

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

Under Pressure: Climate Change, Upwelling, and Eastern Boundary Upwelling Ecosystems

Time series analysis of data for sea surface temperature and upwelling components from the southwest coast of Portugal

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