Climate Change Impacts on the Patagonian Shelf Break Front

Franco, Bárbara Cristie; Ruiz-Etcheverry, Laura A.; Marrari, Marina; Piola, Alberto R.; Matano, Ricardo P.

doi:10.1029/2021gl096513

Cited by 23 publications

(22 citation statements)

References 39 publications

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“…Our results (see R7 and R2 in Table 1) are consistent with recent studies reporting a warming trend of 0.4° decade -1 in the Brazil-Malvinas Confluence and the SBF (e.g. Franco et al, 2020Franco et al, , 2022 as well as in the San Matías and Nuevo Gulfs (Williams and Nocera, 2023). Also, a higher water temperature associated with global warming is predicted over the shelf where the heat exchange between the sea and the atmosphere is strong (Leyba et al, 2019), and this is in agreement with the most pronounced warming trend found in our study.…”

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 92%

“…The depth and properties of the MLD depend on ocean-atmosphere exchanges which are strongly influenced by climate variability (Sallée et al, 2010). Our results indicate consistent shallowing of the MLD (Table 1) and agree with a previous study which address a shoaling trend of the MLD in the Patagonian Shelf (Franco et al, 2023;Williams and Nocera, 2023), with the highest values in the north-western portion of the mid-shelf and the shelf-break (Franco et al, 2022), also in line with the highest trend find in R7 of this study. In the Patagonian shelf the MLD depends mainly on the thermal stratification (Signorini et al, 2006); thus, the increase in SST due to global warming is expected to produce longer periods of shallower MLD (typical of spring and summer), resulting in the negative observed trend.…”

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 92%

“…The significant trends in Chl-a concentration and phenology indexes presented in this study may be influencing the marine system functioning as they describe changes at the base of the food web, and several factors could be leading these strong trends. In line with our results, previous studies addressed the increasing trend of Chl-a concentration covering then entire Patagonian Shelf or the SBF (Marrari et al, 2017;Franco et al, 2022), but none studies of trends of phenological indices was performed before. Franco et al…”

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 86%

“…(2022) suggested an intensification of the SBF results from a cooling of the MC (SST negative trend in R8, Table 1) and a warming of the adjacent shelf (SST positive trend in R7, Table 1). It combines with the intensification of winds parallel to the front (Risaro et al, 2022) that may enhance the turbulent mixing and increase the upwelling on the onshore side of the front (Franco et al, 2022). All these changes combined would benefit phytoplankton and increase their productivity.…”

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...mentioning

confidence: 99%

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Patterns and trends in Chlorophyll-a concentration and phytoplankton phenology in the biogeographical regions of Southwestern Atlantic

Delgado

Hernández‐Carrasco²,

Combes

et al. 2023

Preprint

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The Southwestern Atlantic Ocean (SAO), is considered as one of the most productive areas of the world, with high abundance of ecologically and economical important fish species. Yet, the biological responses of this complex region to climate variability are still uncertain. Here, using 24 years of satellite derived Chl-a datasets, we classified the SAO into coherent regions based on homogeneous temporal variability of Chl-a concentration, as revealed by the SOM (Self-Organizing Maps) analysis. These coherent biogeographical regions were the basis of our regional trend analysis in phytoplankton biomass, regional phenological indices, and environmental forcing variations. A generalized positive trend in phytoplankton concentration is observed, especially in the highly productive areas of the northern shelf-break, where phytoplankton biomass is increasing at an outstanding rate up to 0.42 ± 0.04 mg m-3 per decade associated with the sea surface temperature (SST) warming (0.11 ± 0.02 °C decade-1) and the mixed layer depth shoaling (-3.36 ± 0.13 m decade-1). In addition to the generalized increase in chlorophyll, the most sticking changes in phytoplankton dynamics observed in the SAO are related to the secondary bloom that occurs in most of the regions (15 ± 3 and 24 ± 6 days decade-1) which might be explained by the significant warming trend of SST, which would sustain the water stratification for a longer period, thus delaying the secondary bloom initialization. Consistent with previous studies, our results provided further evidences of the impact of climate change in these highly productive waters.

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Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 92%

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 92%

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...supporting

confidence: 86%

Section: Environmental Phytoplankton Biomass and Phenology Trends In ...mentioning

confidence: 99%

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Patterns and trends in Chlorophyll-a concentration and phytoplankton phenology in the biogeographical regions of Southwestern Atlantic

Delgado

Hernández‐Carrasco²,

Combes

et al. 2023

Preprint

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show abstract

“…Such a diet switch has been recorded in the North Pacific blackfooted albatross Phoebastria nigripes that increased discard consumption during a year of record-high SST (Conners et al, 2018) and also in the Benguela system where Cape gannets Morus capensis increased discard consumption when natural prey were scarce (Tew Kai et al, 2013;Cohen et al, 2014). In light of predicted rising sea surface temperatures as a result of climate change (IPCC, 2019;Franco et al, 2022), this pattern warrants particular attention in the context of conservation. The impact of environmental and fishery effects on prey availability are likely to be highly complex and systemspecific, however (Inchausti et al, 2003;Rolland et al, 2008;Wren et al, 2019).…”

Section: Relationship Between Breeding Success Discards and Foraging ...mentioning

confidence: 88%

Prey-switching to fishery discards does not compensate for poor natural foraging conditions in breeding albatross

Kuepfer

Votier

Sherley

et al. 2022

ICES Journal of Marine Science

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Fishery discards supplement food for many seabirds, but the impacts of declining discards are poorly understood. Discards may be beneficial for some populations but have negative impacts by increasing bycatch risk or because they are junk-food. The Falkland Islands support > 70% of global black-browed albatross Thalassarche melanophris populations, which feed on discards. However, the effect of discards on population demographics, and implications of fishery management changes, are unknown. We analysed stomach contents of black-browed albatross chicks across eight breeding seasons (2004–2020) from New Island, Falkland Islands, to assess variation in discard consumption and how this relates to foraging conditions and breeding success. Across years, 68%–98% of samples contained natural prey, whilst 23%–88% of samples contained fishery discards. Discard consumption was positively related to fishery catches of hoki Macruronus magellanicus and sea surface temperature anomalies SSTA (°C), and negatively related to breeding success. These results suggest a diet-switching behaviour for Falkland Islands albatrosses, whereby birds switch from preferred natural prey to suboptimal discards when environmental conditions, and hence natural feeding opportunities, are unfavourable. Crucially, this study highlights that fishery discards do not compensate for poor natural foraging conditions for breeding albatrosses in the long term.

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Air–sea heat fluxes variations in the Southern Atlantic Ocean: Present‐day and future climate scenarios

Moura,

de Souza,

Casagrande

et al. 2024

Intl Journal of Climatology

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This study investigates the variations in air–sea heat fluxes and temperatures in two ocean front regions, the Southwestern Atlantic Ocean (SWA) and the Drake Passage, widely recognized as hotspot areas with significant influences on South America weather and climate. We analyse means and trends of latent and sensible heat fluxes (LHF and SHF) and their associated air–sea temperatures (SAT and SST), based on monthly ERA5 (1985–2014) and eight CMIP6 models, for historical and long‐term simulations (2015–2099). The ERA5 trend for all parameters was positive over SWA, contrasting with the negative values observed in the Drake Passage, indicating surface warming and cooling, respectively. In the SWA, the ERA5 and CMIP6 multi‐model ensemble (MME) align in SST and SAT values, with a historical trend of 0.1°C·decade−1 and a significantly increasing trend in warming estimated by 0.4°C·decade−1 up to 2099. The ERA5 LHF and SHF trends were 4 and 0.6 W·m−2·decade−1, respectively. The MME shows historical (SSP5‐8.5) trends of 0.2 (1.3) W·m−2·decade−1 for LHF and −0.2 (−0.1) W·m−2·decade−1 for SHF. In the Drake Passage, the models accurately reproduced the air–sea mean temperatures; however, they failed to simulate negative trends observed in SAT and SST. Under the high emissions scenario, all CMIP6 models predict an increasing warming trends of 0.1–0.4°C·decade−1 and ocean heat gain of −0.2 to −1.2 (−1 to −2) W·m−2·decade−1 for LHF (SHF). For both regions, spatial analyses of SST and SAT highlight the coupling between the ocean and the atmosphere, alongside changes in air–sea heat fluxes. Our findings reveal inhomogeneous patterns of SST warming trends by the end of the 21st century, which are approximately 2–4 times greater than historical trends. The results suggest the persistence and enhancement of these regions as hotspots with significant potential to influence oceanic and atmospheric dynamics.

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Climate Change Impacts on the Patagonian Shelf Break Front

Cited by 23 publications

References 39 publications

Patterns and trends in Chlorophyll-a concentration and phytoplankton phenology in the biogeographical regions of Southwestern Atlantic

Patterns and trends in Chlorophyll-a concentration and phytoplankton phenology in the biogeographical regions of Southwestern Atlantic

Prey-switching to fishery discards does not compensate for poor natural foraging conditions in breeding albatross

Air–sea heat fluxes variations in the Southern Atlantic Ocean: Present‐day and future climate scenarios

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