The Effect of Agulhas Eddies on Absorption and Transport of Anthropogenic Carbon in the South Atlantic Ocean

Orselli, Iole B.M.; Goyet, Catherine; Kerr, Rodrigo; Azevedo, José de; Araújo, Moacyr; Galdino, Felippe; Touratier, Franck; Garcia, Carlos Alberto Eiras; Azevedo, José Luiz Lima de

doi:10.3390/cli7060084

Cited by 10 publications

(11 citation statements)

References 67 publications

(117 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mesoscale eddies, characterised by radii on the order of 100 km and lifetimes of weeks to years, are ubiquitous in the global oceans (Chelton et al, 2011;Pegliasco et al, 2022). Eddies modify the physical (Laxenaire et al, 2019;Nencioli et al, 2018), biological (Carvalho et al, 2019;Dufois et al, 2016;Lehahn et al, 2011;Roughan et al, 2017), and chemical (Arhan et al, 2011;Chen et al, 2007;Orselli, Goyet, et al, 2019; characteristics of the ocean compared to the surrounding waters and can be advected far away from their origin.…”

Section: Introductionmentioning

confidence: 99%

Mesoscale eddies enhance the air-sea CO2 sink in the South Atlantic Ocean

Ford

Tilstone

Shutler

et al. 2022

Preprint

View full text Add to dashboard Cite

Mesoscale eddies are abundant in the global oceans and known to affect marine biogeochemistry. Understanding their cumulative impact on the air-sea carbon dioxide (CO2) flux is likely important for quantifying the ocean carbon sink. Here, observations and Lagrangian tracking are used to estimate the air-sea CO2 flux of 67 long lived (i.e. > 1 year) mesoscale eddies in the South Atlantic Ocean over a 16 year period. We find that anticyclonic eddies originating from the Agulhas retroflection and cyclonic eddies originating from the Benguela upwelling act as net CO2 sinks over their lifetimes. In combination, the eddies significantly enhanced the CO2 sink into the South Atlantic Ocean by 0.08 ± 0.01%. Although this modification appears small, long lived eddies account for just ~0.4% of global ocean eddies and eddy activity is increasing; therefore, explicitly resolving eddy processes within all models used to assess the ocean carbon sink would appear critical.

show abstract

Section: Introductionmentioning

confidence: 99%

Mesoscale eddies enhance the air-sea CO2 sink in the South Atlantic Ocean

Ford

Tilstone

Shutler

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…A decay of the Agulhas rings toward the west was evident from SLA (Carvalho et al, 2019;Orselli et al, 2019). Each eddy proved to be different, with different physical and chemical characteristics and different species' presence.…”

Section: Discussionmentioning

confidence: 92%

“…The youngest eddy, E1, was the most discrepant, having the highest vorticity, more nutrients, and a greater density of organisms, and was the only eddy with STMW14. Orselli et al (2019) represented the formation of the eddies of the present study in a video, in which it is possible to observe the start of the formation of E1 with a high SLA. Carvalho et al (2019) suggested that E1, located in the South Atlantic Ocean's eastern basin, represented a younger and stronger structure and a more diverse phytoplankton community (HPLC pigments analysis) than E3 and E5.…”

Section: Discussionmentioning

confidence: 96%

“…In the first effort to evaluate the microplankton functional diversity within Agulhas rings of different ages, this study sampled during the FORSA cruise in the South Atlantic Ocean. Previous studies have investigated plankton diversity, ecology, and dynamics in oligotrophic waters of the South Atlantic subtropical gyre (Lee and Williams, 2000;Oschlies, 2002;Lévy, 2003); and Agulhas rings (Villar et al, 2015;Carvalho et al, 2019;Orselli et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…During the FORSA cruise, six Agulhas rings were sampled, but plankton samples were collected in three eddies of different ages (E1, 7 months; E3, 11 months; E5, 24 months). The eddies ages were determined through satellite images (AVISO) of the moment of their formation in the retroflection area (Guerra et al, 2018;Orselli et al, 2019).…”

Section: The Forsa Cruisementioning

confidence: 99%

See 2 more Smart Citations

Is Oligotrophy an Equalizing Factor Driving Microplankton Species Functional Diversity Within Agulhas Rings?

et al. 2020

View full text Add to dashboard Cite

From the southwestern termination of the Agulhas current, anticyclonic eddies are emitted and drift across the South Atlantic Ocean. This study is based on a FORSA (Following Ocean Rings in the South Atlantic) oceanographic cruise, from Cape Town (South AFRica) to Arraial do Cabo (Brazil) in June 2015, during which three eddies of different ages (E1, 7 months; E3, 11 months; E5, 24 months) from the Agulhas current were sampled for microplankton identification and determination of functional traits. The stations where sampling occurred at each eddy included a control outside the eddy and three stations inside the eddy—border, midway (between the border and center), and center (identified through satellite images of sea level anomaly—SLA). Functional traits were determined based on microscopic observations and consultation of the literature. An evident decay in the Agulhas eddies toward the west was observed, and each eddy proved to be different. E1 represented a younger and more robust structure. At the same time, the other eddies, E3 and E5, were more alike with similar physical, chemical, and ecological characteristics and almost the same indices values of functional diversity, demonstrating that although their species compositions were different, the strategies used by the species were the same. The most crucial ecological trait for microplankton was nutrition mode. The microplankton contained mainly mixotrophic dinoflagellates and cyanobacteria adapted to oligotrophic conditions. The functional strategy of microplankton did not differ among the eddies and stations, with mixotrophy being the most striking trait. Therefore, the older eddies’ microplankton community fits the neutrality theory, whereby species perform similar ecological functions, and the younger eddy fits in the niche complementarity. Even with the species composition being different in each eddy and/or within the same eddy, the functional strategy was the same, with scarce resources and species selected that best use any source of nutrients or use evolutionary advantages to live in an oligotrophic environment.

show abstract