The impact of mesoscale eddies on the phytoplankton community in the South Atlantic Ocean: HPLC-CHEMTAX approach

Carvalho, Andréa da Consolação de Oliveira; Mendes, Carlos; Kerr, Rodrigo; Azevedo, José Luiz Lima de; Galdino, Felippe; Tavano, Virgínia Maria

doi:10.1016/j.marenvres.2018.12.003

Cited by 15 publications

(18 citation statements)

References 71 publications

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“…CHEMTAX uses a factor analysis and steepest descent algorithm to best fit the data onto an initial matrix of pigment ratios (the ratios between the respective accessory pigments and Chl a). This software package has been extensively and successfully used in many worldwide investigations (Mendes et al 2011;Schlüter et al 2011;Araujo et al 2017;Carvalho et al 2019;Lima et al 2019), including in the Southern Ocean (e.g., Rodríguez et al 2002;Wright et al 2010;Mendes et al 2012Mendes et al , 2015, to determine the distribution and Chl a biomass of phytoplankton functional groups. This approach provides valuable information about the whole phytoplankton community, including small-size species, which are normally difficult to identify by light microscopy.…”

Section: Chemical Taxonomy Analysis Of Pigment Datamentioning

confidence: 99%

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Costa

Mendes

Tavano

et al. 2020

Limnology & Oceanography

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Diatoms are considered the main base of the Southern Ocean food web as they are responsible for more than 85% of its annual primary production and play a crucial role in the Antarctic trophic structure and in the biogeochemical cycles. Within this context, an intense diatom bloom reaching > 45 mg m−3 of chlorophyll a was registered in the Northern Antarctic Peninsula (NAP) during a late summer study in February 2016. Given that nutrient concentrations and grazing activities were not identified here as limiting factors on the bloom development, the aim of this study was to evaluate the effect of water column structure (stability and upper mixed layer depth) on the phytoplankton biomass and composition in the NAP. The diatom bloom, mainly composed by the large centric Odontella weissflogii (mostly > 70 μm in length), was associated with a local ocean carbon dioxide uptake that reached values greater than −60 mmol m−2 d−1. We hypothesize that the presence of a vertically large water column stability barrier, just below the pycnocline, was the main driver allowing for the development of the intense diatom bloom, particularly in the Gerlache Strait. Contrarily, a shift from diatoms to dinoflagellates (mainly Gymnodiniales < 20 μm) was observed associated with conditions of a highly stable thin layer. The results suggest that a large fraction of this intense diatom bloom is in fast sinking process, associated with low grazing pressure, showing a crucial role of diatoms for the efficiency of the biological carbon pump in this region.

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Section: Chemical Taxonomy Analysis Of Pigment Datamentioning

confidence: 99%

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Costa

Mendes

Tavano

et al. 2020

Limnology & Oceanography

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“…After being shed from the Agulhas Current retroflection offshore of the southern tip of AFRica, between longitudes 16 • E and 20 • E, the eddies drift initially embedded in the Benguela Current, overcome the Walvis Ridge, and then follow W-NW through the South Atlantic with some even reaching the western boundary (Lutjeharms and Van Ballegooyen, 1988;Gordon and Haxby, 1990;Byrne et al, 1995;Guerra et al, 2018). As recently discussed, such rings can also transport plankton over long distances from the source region (Villar et al, 2015;Carvalho et al, 2019). The environment within Agulhas rings may create a selective mechanism, with higher nutrient concentrations than the oligotrophic surface water of the Atlantic Ocean, and associated phytoplankton blooms dominated by opportunistic species nitrate-metabolizing Synechococcus spp.…”

Section: Introductionmentioning

confidence: 84%

“…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%

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

et al. 2020

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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.

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“…The first leg (TAII_01) was conducted from October 24th to November 25th along 35 • S (from Rio Grande, Brazil, to Cape Town, South Africa) [38], and the second leg (TAII_02) was conducted from December 2nd to December 22nd in a Southwestern-Northeastern section (from Cape Town, South Africa, to Rio de Janeiro, Brazil). The FORSA cruise occurred in 2015 on board the Brazilian Navy RV, NPqHo Vital de Oliveira from June 27th to July 15th in a Southwestern-Northeastern section (from Cape Town, to South Africa to Arraial do Cabo, to Brazil) [34,39]. Along these cruise tracks, hydrographic conductivity-temperature-depth (CTD) stations were sampled: 93 in 2011 during the TAII and 12 in 2015 during the FORSA cruise.…”

Section: Cruises Surveysmentioning

confidence: 99%

“…During the FORSA cruise, eddy identification was conducted by analyzing the daily Sea Level Anomaly (SLA) data in conjunction with the temperature profiles obtained by high-resolution spatially distributed XBT deployments. Once the eddies were found, water sampling was performed inside and outside of them (see Carvalho et al [39] for details). The FORSA cruise was the only one previously planned to sample the Agulhas eddies, and, therefore, we needed to identify the eddies sampled in all of the other cruises, as well as their positions.…”

Section: Identification Of the Agulhas Eddiesmentioning

confidence: 99%

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

Orselli

Goyet²,

Kerr

et al. 2019

Climate

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The South Atlantic Ocean is currently undergoing significant alterations due to climate change. This region is important to the global carbon cycle, but marine carbon data are scarce in this basin. Additionally, this region is influenced by Agulhas eddies. However, their effects on ocean biogeochemistry are not yet fully understood. Thus, we aimed to model the carbonate parameters in this region and investigate the anthropogenic carbon (Cant) content in 13 eddies shed by the Agulhas retroflection. We used in situ data from the CLIVAR/WOCE/A10 section to elaborate total dissolved inorganic carbon (CT) and total alkalinity (AT) models and reconstruct those parameters using in situ data from two other Brazilian initiatives. Furthermore, we applied the Tracer combining Oxygen, inorganic Carbon, and total Alkalinity (TrOCA) method to calculate the Cant, focusing on the 13 identified Agulhas eddies. The CT and AT models presented root mean square errors less than 1.66 and 2.19 μmol kg−1, indicating Global Ocean Acidification Observing Network climate precision. The Cant content in the Agulhas eddies was 23% higher than that at the same depths of the surrounding waters. We observed that Agulhas eddies can play a role in the faster acidification of the South Atlantic Central Water.

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The impact of mesoscale eddies on the phytoplankton community in the South Atlantic Ocean: HPLC-CHEMTAX approach

Cited by 15 publications

References 71 publications

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

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

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

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