Annual hydrographic variability in Antarctic coastal waters infused with glacial inflow

Abstract

Abstract. During the 38 months between December 2018 and January 2022, multiparameter hydrographic measurements were taken at 31 sites within Admiralty Bay, King George Island, Antarctica. These records consisted of water column measurements (down to 100 m) of temperature, conductivity, turbidity, and pH as well as the dissolved oxygen, dissolved organic matter, chlorophyll-a and phycoerythrin contents. The sites were chosen due to their variable distances from glacial fronts and open ocean waters. Fifteen sites were localized within smaller glacial coves, with waters highly impacted by glacial infusions; seven sites were located in the open waters of the main body of Admiralty Bay; and nine sites were located in the intermediate conditions of the Ezcurra Inlet. The final dataset consists of measurements carried out over 142 separate days, with an average of 3.74 measurements per month. However, data were not collected regularly throughout the year and were collected less frequently during winter, although data were gathered for all but 2 winter months. On average, each site was investigated 98.2 times. Due to calibration issues, absolute values of optically measured properties occasionally show unrealistic negative values, but the relative distributions of these values remain valid. Variabilities in the measured properties each season and throughout the whole duration of the project reveal regular oscillations as well as possible long-term trends. The described dataset is freely available at PANGAEA: https://doi.org/10.1594/PANGAEA.947909 (Osińska et al., 2022).

Influence of glacial influx on the hydrodynamics of Admiralty Bay, Antarctica - a case study based on combined hydrographic measurements and numerical modeling

“…No evidence of fresher water plumes in subsurface layers was detected (Fig. 2 h and more details in Osińska et al, 2023). Hence, the GMW continuously exhibits the highest buoyancy among the water masses in the AB region, a finding that has been corroborated by prior investigations conducted in the area (Meredith et al, 2018;Monien et al, 2017;Osińska et al, 2021).…”

“…The typical density anomaly of water entering through the open boundary and that of the meltwater is σ=27.4 kg/m 3 (at S=34.1 PSU and T=0.2 ˚C) and σ=0 kg/m 3 (at S=0 PSU and manuscript submitted to JGR Oceans T=0˚C), respectively. The highest recorded value of surface water temperature observed in AB in the summer was 3.54 ˚C, which was exceptionally high (Osińska et al, 2023); the corresponding density anomaly at S=32.56 PSU is σ=26.0 kg/m 3 . Therefore, the contribution of temperature to the net variability of water density in AB is minor.…”

“…The openly accessible data up until January 2022 can be found in the PANGAEA repository (Osińska et al 2022). Detailed information regarding the scope and methodology of data collection is described in Osińska et al (2023). Measurements conducted using an unaltered methodology have continued up until February 2023, and their findings have been analyzed in this study.…”

“…S2) with seasonal mean temperature and salinity variations of -1.23-0.51˚C and 34.22 -34.27 PSU. The in situ measurement results from Osińska et al (2023) were used to determine initial values of water salinity and temperature inside AB, which were uniformly set throughout the domain. It has been found during preliminary model testing that after less than three days of simulations, the salinity stratification in the whole bay was predominantly influenced by the open boundary input, therefore no variation in the initial conditions setting was necessary.…”

Influencia glaciar en la composición y diversidad de la comunidad del fitoplancton marino en la Bahía Almirantazgo, Isla Rey Jorge, Antártida

“…Asimismo, se tomaron registros en Estrecho de Bransfield con el perfilador CTD. Adicionalmente, se descargaron y procesaron los datos fisicoquímicos de Bahía Almirantazgo recolectados durante enero de 2020 en las 3 profundidades disponibles en el repositorio de PANGEA (https://doi.org/10.1594/PANGAEA.947909) obtenidos por Osińska et al (2023).…”