Algal pigment patterns and phytoplankton assemblages in different water masses of the Río de la Plata maritime front

Carreto, José I.; Montoya, Nora G.; Akselman, Rut; Carignan, Mario O.; Silva, Ricardo I.; Colleoni, Daniel A. Cucchi

doi:10.1016/j.csr.2007.02.012

Cited by 61 publications

(44 citation statements)

References 54 publications

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“…Chlorophyll values were in the same range as in other turbid estuaries (ALPINE; CLOERN, 1988) and in previous research in the Río de la Plata (NAGY et al, 2002;CARRETO et al, 2003;CALLIARI et al, 2005;CARRETO et al, 2008). Higher values were found in spring in accordance with the annual cycle proposed for other temperate water bodies (PARSONS et al, 1977).…”

Section: Discussionsupporting

confidence: 86%

“…Combined with turbidity, the water column mixing due to the scarce depth could cause the phytoplankton to stay most of the time in darkness, thus experiencing a loss in biomass (COLE et al, 1992). Although several oceanographic research projects have been undertaken in the Río de la Plata , NAGY et al, 2002, CALLIARI et al, 2005CARRETO et al, 2008), most of them have analyzed large scale processes involving the whole estuary. Our goal is to differentiate domains by means of hydrological and biological variables involving mesoscale processes, and areas with greater or lesser phytoplankton biomass and different species composition in this part of the estuary and review their biological importance.…”

Section: Introductionmentioning

confidence: 99%

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Delimitation of domains in the external Río de la Plata estuary, involving phytoplanktonic and hydrographic variables

Martínez

Ortega

2015

Braz. j. oceanogr.

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Autumn and spring hydrological (temperature and salinity) and biological (chlorophyll, phaeopigments and phytoplankton species) variables were analysed. Phytoplankton biomass, expressed as chlorophyll a reach a maximum of 6.1 µg L-1in autumn and 22.8 µg L-1 during spring. Maxima were found in the frontal zone and marine adjacent area. Four domains were identified through multivariate analysis: Riverine, Estuarine, Frontal and Oceanic; mainly due to salinity and depth in autumn and due to salinity and chlorophyll in spring. The Riverine and Oceanic domains (West and East boundaries) matched in location in both seasons, while in spring an additional domain was discerned in the Canal Oriental (Channel domain). Salinity and chlorophyll concentration increased from the Riverine to the Frontal domain, being positively correlated for salinities 14, indicating that chlorophyll concentration was modulated mainly by the oceanic influence that improved light availability. While salinity maintains an increasing trend toward the Oceanic domain, phytoplankton biomass decreases. Though in this zone the chlorophyll concentration must be regulated by a combination of light availability and grazing, further investigation is needed.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Delimitation of domains in the external Río de la Plata estuary, involving phytoplanktonic and hydrographic variables

Martínez

Ortega

2015

Braz. j. oceanogr.

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“…These diatom species are also found in Antarctic waters (Gonçalves-Araujo et al, 2015), indicating that Antarctic and subantarctic communities have an important influence on the southern Patagonian region, through advection of subantactic water from the shelf-break region (Olguín et al, 2006;Olguín and Alder, 2011;Gonçalves-Araujo et al, 2012;Olguín Salinas et al, 2015). Such predominance of diatoms in spring has been described for other domains across the Argentine Sea such as the northern shelf, in the La Plata outflow region (Carreto et al, 2008), shelfbreak (Olguín et al, 2006;Garcia et al, 2008;Segura et al, 2013), farther offshore (Olguín et al, 2006;Olguín Salinas et al, 2015) and in subantarctic waters at the Brazil-Malvinas Confluence (Gonçalves-Araujo et al, 2012). Moreover, it is a tenet of phytoplankton ecology that the dominance of fast growing diatoms in temperate latitudes is mainly related to water column structure, through the establishment of sunlit surface waters containing winter-accumulated nutrients, which triggers massive spring phytoplankton blooms (Sverdrup, 1953).…”

Section: Phytoplankton Seasonal Changementioning

confidence: 75%

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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“…Thus, a need exists to define ratios and especially their variability in ways that will allow reliable/verifiable estimates of chl a contributions for each taxon (Peeken 1997, Jeffrey et al 1999 or 'plankton functional group' (PFG; Paerl et al 2003), as summarized in this quote: 'The biggest problem remaining for all such techniques is the paucity of data available for pigment ratios of major species over a wide range of light and nutrient regimes' (Jeffrey et al 1999, p. 890). This is especially critical since past studies (Carreto et al 2008) have shown a logarithmic decrease in pigments (e.g. chl a per cell) and decreasing chl a:marker pigment ratios with increasing irradiance.…”

Section: Introductionmentioning

confidence: 99%

Microalgal pigment ratios in relation to light intensity: implications for chemotaxonomy

Grant¹,

Louda²

2010

Aquat. Biol.

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Pigment-based chemotaxonomy relies upon the assertion that the pigment arrays of mixed microalgal communities (phytoplankton, periphyton, microphytobenthos) can be deconvoluted in ways to provide an estimate of taxon-specific chlorophyll a (chl a) as a proxy for biomass. This relies on having valid chl a:biomarker pigment ratios. However, pigment ratios change for a variety of reasons. We examined the effects of only light intensity (photon flux density, PFD) on the pigment ratios of 10 species in the phyla Cyanobacteria, Chlorophyta, Chromophyta (Bacillariophyceae), Haptophyta, and Pyrrophyta. Chl a:marker pigment versus PFD (30-45 through 1800 µmol quanta m -2 s -1 ) data revealed distinct trends for photosynthetic accessory pigments (PAP) versus photoprotective pigments (PPP). Chl a:PAP class pigments (chl b, fucoxanthin, peridinin, echinenone) exhibited relative stability (possibly stoichiometry) with increasing PFD, while chl a:PPP class pigment trends revealed large increases in the relative amounts of the PPP pigments (zeaxanthin, myxoxanthophyll, canthaxanthin, scytonemins). Total chl a cell -1 often decreases in concert with increasing PFD and partially or totally explains the decrease in chl a:PPP ratios. We verified that all 'xanthophyll cycle' pigments expressed large and erratic ratios and therefore did not predict chl a levels. We conclude that light (400 to 700 nm) measurements taken in the field can offer valuable ancillary data for adjusting pigment-based chemotaxonomic formulae for the study of microalgal communities. Pigments that have a light-harvesting function (photosynthetic accessory pigments; PAP) in photosynthesis tend to covary with chl a (Green & Durnford 1996), while those that appear to have a photoprotective function (photoprotective pigments; PPP) can be expected to increase in high light intensities (Goericke & Montoya 1998).Xanthophyll cycle pigments change rapidly in concert with photic flux and light:dark cycles. These include carotenoid ↔ carotenoid epoxide conversions in chlorophytes (zeaxanthin, ZEA ↔ antheraxanthin, ANTH ↔ violaxanthin, VIOLA; Demmig-Adams 1990) and chromophytes (diatoxanthin, DX ↔ diadinoxanthin, DD; Hager 1980). Given the rapid changes in these series, it can then be argued that none of these pigments can exist in reliable or useable quantitative relationships with chl a. However, the sum of xanthophyll cycle pigments (ZEA+ANTH+VIOLA or DD + DX) may yield meaningful information as to the chemotaxonomic and/or light history of microalgal communities and indicate specific biomarker ratio values to be used when a certain photic history is inferred. The 'epoxidation state' (EPS) of the xanthophylls cycle (EPS = [VIOLA + 0.5 ANTH] / [VIOLA + ANTH + ZEA]; Thayer & Bjorkman 1992) may also provide insight as to light history over the short (~ hours to days) term.Additional complications in pigment interpretations arise if senescent, dead, or grazed materials are present in the natural seston, periphyton, or microphytobenthos being analyzed. In these ca...

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Algal pigment patterns and phytoplankton assemblages in different water masses of the Río de la Plata maritime front

Cited by 61 publications

References 54 publications

Delimitation of domains in the external Río de la Plata estuary, involving phytoplanktonic and hydrographic variables

Delimitation of domains in the external Río de la Plata estuary, involving phytoplanktonic and hydrographic variables

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

Microalgal pigment ratios in relation to light intensity: implications for chemotaxonomy

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