Physical-biological drivers modulating phytoplankton seasonal succession along the Northern Antarctic Peninsula

Costa, Raul Rodrigo; Ferreira, Afonso; Souza, Márcio Silva de; Tavano, Virgínia Maria; Kerr, Rodrigo; Secchi, Eduardo R.; Brotas, Vanda; Dotto, Tiago S.; Brito, Ana C.; Mendes, Carlos

doi:10.1016/j.envres.2023.116273

Cited by 3 publications

(1 citation statement)

References 46 publications

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“…Therefore, we assumed that summer macronutrient concentrations below the upper mixed layer depth (below 50 m) were representative of macronutrient concentrations at the sea surface (above 50 m) in the previous winter, as has been shown in other studies in adjacent regions (Henley et al 2018). Although the upper mixed layer depth is expected to vary both spatially and temporally, the choice of the 50-m threshold is consistent with in situ measurements over the long time series at Palmer Station (Kim et al 2016) and spatially along the northern Antarctic Peninsula (Costa et al 2020(Costa et al , 2023. Moreover, the range (À1.96 C to 1.10 C) and average (À0.74 AE 0.44 C) of minimum temperature between 50 and 100 m in summer are in reasonable agreement with the range (À1.97 C to À0.76 C) and average (À1.54 AE 0.23 C) of minimum temperature between 0 and 50 m in winter from the northern Antarctic Peninsula seasonal hydrographic climatology (Dotto et al 2021).…”

Section: Seasonal Macronutrient Drawdownsupporting

confidence: 85%

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

Monteiro,

Henley,

Pollery

et al. 2023

Limnology & Oceanography

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The northern Antarctic Peninsula is a key region of the Southern Ocean due to its complex ocean dynamics, distinct water mass sources, and the climate‐driven changes taking place in the region. Despite the importance of macronutrients in supporting strong biological carbon uptake and storage, little is known about their spatiotemporal variability along the northern Antarctic Peninsula. Hence, we explored for the first time a 24‐year time series (1996–2019) in this region to understand the processes involved in the spatial and interannual variability of macronutrients. We found high macronutrient concentrations, even in surface waters and during strong phytoplankton blooms. Minimum concentrations of dissolved inorganic nitrogen (DIN; 16 μmol kg−1), phosphate (0.7 μmol kg−1), and silicic acid (40 μmol kg−1) in surface waters are higher than those recorded in surrounding regions. The main source of macronutrients is the intrusions of Circumpolar Deep Water and its modified variety, while local sources (organic matter remineralization, water mass mixing, and mesoscale structures) can enhance their spatiotemporal variability. However, we identified a depletion in silicic acid due to the influence of Dense Shelf Water from the Weddell Sea. Macronutrient concentrations show substantial interannual variability driven by the balance between the intrusions of modified Circumpolar Deep Water and advection of Dense Shelf Water, which is largely modulated by the Southern Annular Mode (SAM) and to some extent by El Niño‐Southern Oscillation (ENSO). These findings are critical to improving our understanding of the natural variability of this Southern Ocean ecosystem and how it is responding to climate changes.

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Section: Seasonal Macronutrient Drawdownsupporting

confidence: 85%

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

Monteiro,

Henley,

Pollery

et al. 2023

Limnology & Oceanography

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Particulate Organic Matter in the Northern Antarctic Peninsula: Distribution, Composition, and Drivers

Rocha,

Machado,

Camargo

et al. 2024

Preprint

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Biophysical coupling of seasonal chlorophyll-a bloom variations and phytoplankton assemblages across the Peninsula Front in the Bransfield Strait

Veny,

Aguiar-González,

Marrero-Díaz

et al. 2024

Ocean Sci.

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Abstract. This study investigates the spatio-temporal variations in the chlorophyll-a (chl-a) blooms in the Bransfield Strait (BS) at a climatological scale (1998–2018). We propose that suitable monitoring of these blooms can be achieved through remotely sensed observations only if the BS is divided following the Peninsula Front (PF), which ultimately influences the phytoplankton assemblage. Our analysis is based on characterizing climatological fields of sea surface temperature (SST), air temperature, sea ice coverage, chl-a concentrations and wind stress, guided by synoptic novel and historical in situ observations which reveal two niches for phytoplankton assemblage: the Transitional Bellingshausen Water (TBW) and Transitional Weddell Water (TWW) pools. The TBW pool features stratified, less saline, warmer waters with shallow mixed layers, while the TWW pool features well-mixed, saltier, and colder waters. We identify that the 0.6 °C isotherm corresponds to the summertime climatological PF location, effectively dividing the BS into two different scenarios. Furthermore, the 0.5 mg m−3 chl-a isoline aligns well with the 0.6 °C isotherm, serving as a threshold for chl-a blooms of the highest concentrations around the South Shetland Islands. For the first time, these thresholds enable the monthly climatological descriptions of the two blooms developing in the BS on both sides of the PF. We think this approach underscores the potential of combining SST and chl-a data to monitor the year-to-year interplay of the chl-a blooms occurring in the TBW and TWW pools contoured by the PF.

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Physical-biological drivers modulating phytoplankton seasonal succession along the Northern Antarctic Peninsula

Cited by 3 publications

References 46 publications

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

Particulate Organic Matter in the Northern Antarctic Peninsula: Distribution, Composition, and Drivers

Biophysical coupling of seasonal chlorophyll-a bloom variations and phytoplankton assemblages across the Peninsula Front in the Bransfield Strait

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