Cross-frontal distribution of inorganic nutrients and chlorophyll-a on the Patagonian Continental Shelf of Argentina during summer and fall

Paparazzo, Flavio Emiliano; Bianucci, Laura; Schloss, Irene R; Almandoz, Gastón O.; Solis, Miriam Edith; Esteves, José Luís

doi:10.4067/s0718-19572010000100010

Cited by 28 publications

(25 citation statements)

References 23 publications

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“…Stronger water column stratification in summer as compared to spring in the southern Patagonian shelf was also reported for the austral spring/summer season of 2005(Dogliotti et al, 2014. The range of nutrient concentrations observed in this study agrees with previous reports for the region (Paparazzo et al, 2010;Paparazzo, 2011;Balch et al, 2014;Valiadi et al, 2014). Even considering our relatively restricted study area, a subtle spatial variation in DIN distribution was observed at surface during the spring season.…”

Section: Taxonomic Groups Spring Summersupporting

confidence: 92%

Seasonal change of phytoplankton (spring vs. summer) in the southern Patagonian shelf

Gonçalves-Araujo

Souza

Mendes

et al. 2016

Continental Shelf Research

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a b s t r a c tAs part of the Patagonian Experiment (PATEX) project two sequential seasons (spring/summer 2007-2008) were sampled in the southern Patagonian shelf, when physical-chemical-biological (phytoplankton) data were collected. Phytoplankton biomass and community composition were assessed through both microscopic and high-performance liquid chromatography/chemical taxonomy (HPLC/ CHEMTAX) techniques and related to both in situ and satellite data at spatial and seasonal scales. Phytoplankton seasonal variation was clearly modulated by water column thermohaline structure and nutrient dynamics [mainly dissolved inorganic nitrogen (DIN) and silicate]. The spring phytoplankton community showed elevated biomass and was dominated by diatoms [mainly Corethron pennatum and small ( o20 mm) cells of Thalassiosira spp.], associated with a deeper and more weakly stratified upper mixed layer depth (UMLD) and relatively low nutrient concentrations, which were probably a result of consumption by the diatom bloom. In contrast, the phytoplankton community in summer presented lower biomass and was mainly dominated by haptophytes (primarily Emiliania huxleyi and Phaeocystis antarctica) and dinoflagellates, associated with shallower and well-stratified upper mixed layers with higher nutrient concentrations, likely due to lateral advection of nutrient-rich waters from the Malvinas Current. The gradual establishment of a strongly stratified and shallow UMLD as season progressed, was an important factor leading to the replacement of the spring diatom community by a dominance of calcifying organisms, as shown in remote sensing imagery and confirmed by microscopic examination. Furthermore, in spring, phaeopigments a (degradation products of chlorophyll a) relative to chlorophyll a, were twice that of summer, indicating the diatom bloom was under higher grazing pressure.

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Section: Taxonomic Groups Spring Summersupporting

confidence: 92%

Seasonal change of phytoplankton (spring vs. summer) in the southern Patagonian shelf

Gonçalves-Araujo

Souza

Mendes

et al. 2016

Continental Shelf Research

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“…This would be the opposite under dominance of other groups and lower phytoplankton biomass [ Schloss et al , 2007]. A relatively low [ chl ] was observed associated to the coccolithophorid bloom found in this cruise, as compared to high concentrations measured in other bloom periods in the Patagonian shelf [ Carreto et al , 1995; Papparazzo et al , 2010] and shelf‐break [ Garcia et al , 2008; Ferreira et al , 2009]. However, even at lower biomass levels, organisms with calcium carbonate shells are known to modify CO 2 levels in the water column [ Zondervan , 2007], supporting the idea that the biological role in controlling gas concentration levels in the Patagonian region depends on the time of the year and the phytoplankton community.…”

Section: Discussionmentioning

confidence: 90%

Environmental conditions and bio-optical signature of a coccolithophorid bloom in the Patagonian shelf

et al. 2011

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[1] In January 2008, a patch of high reflectance detected by ocean color satellite images was sampled during a cruise over the southern Argentinean continental shelf. High calcite concentrations (particulate inorganic carbon (PIC)) found at the patch were associated with dominance of the coccolithophorid Emiliania huxleyi. Relatively low chlorophyll concentrations (0.29 to 1.48 mg m −3 ) were found, but both particulate attenuation (0.27 to 1.15 m −1 ) and backscattering coefficients at 660 nm (0.003 to 0.042 m −1 ) were noticeably high. Particulate inorganic to organic carbon (POC) ratio (PIC:POC) was highly variable (0.02 to 1.1), but mostly high, showing a significant correlation with particulate backscattering coefficient at 660 nm (r = 0.83, p < 0.005). The spectral dependency of the backscattering coefficient followed Gordon et al. (2009). Both the time evolution analyses of normalized water leaving radiance at 551 nm (nLw551) and the high PIC:POC ratios suggested an advanced stage of the coccolithophorid bloom, therefore with high detached coccoliths:cell ratios. Moreover, this was supported by a strong correlation between PIC and both particulate backscattering (r = 0.81, p < 0.005) and particulate beam attenuation coefficient (r = 0.7, p < 0.05). Remote sensing reflectance data were strongly related to particle backscattering and backscattering ratio, but not to absorption. NASA operational algorithms overestimated chlorophyll by a factor of ∼2 and estimated PIC with a relatively high root-mean-square (RMS) error (RMS = 97.9 mg PIC L ) were achieved when we used the original PIC-specific backscattering coefficient (Balch et al., 2005).

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“…8) (Romero et al, 2006;Paparazzo et al, 2010). Moreover, palaeobiogeographical studies have shown colder than present waters of higher productivity during the Late Pleistocene along Patagonia, especially in the southern sector.…”

Section: Accepted Manuscriptmentioning

confidence: 96%

Bioerosion structures in Crepidula (Mollusca, Gastropoda) as indicators of latitudinal palaeoenvironmental changes: Example from the marine Quaternary of Argentina

Richiano

Aguirre

Ester

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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Cross-frontal distribution of inorganic nutrients and chlorophyll-a on the Patagonian Continental Shelf of Argentina during summer and fall

Cited by 28 publications

References 23 publications

Seasonal change of phytoplankton (spring vs. summer) in the southern Patagonian shelf

Seasonal change of phytoplankton (spring vs. summer) in the southern Patagonian shelf

Environmental conditions and bio-optical signature of a coccolithophorid bloom in the Patagonian shelf

Bioerosion structures in Crepidula (Mollusca, Gastropoda) as indicators of latitudinal palaeoenvironmental changes: Example from the marine Quaternary of Argentina

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