Response of a natural Antarctic phytoplankton assemblage to changes in temperature and salinity

ALMANDOZ, GASTÓN O.; VARELA, DIANA E.; PAPARAZZO, FLAVIO E.; FERRARIO, MARTHA E.; ROZEMA, PATRICK D.; SCHLOSS, IRENE R.; ANTONI, JULIETA S.; HERNANDO, MARCELO P.; BUMA, ANITA G.J.

JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY

ELSEVIER SCIENCE BV

Año: 2020 vol. 532

0022-0981

The climate around the Western Antarctic Peninsula (WAP) is rapidly changing and dramatically affecting marine coastal waters. Increases in air and seawater temperatures, not matter how small, can alter coastal biological communities due to both temperature increases as well as salinity reduction from glacier melting. The aim of this study was to evaluate the individual and combined effects of elevated sea surface temperature (+4 °C) and decreased salinity (−4) on growth and assemblage composition of natural summer phytoplankton from Potter Cove (King George Island, South Shetlands, northern WAP), using an outdoor microcosm experiment. Pigment composition was analyzed by high performance liquid chromatography (HPLC/Chemtax) and species composition by light and electron microscopy. Increases in phytoplankton biomass during the first 3 days at elevated-temperatures coincided with an increase in the abundance and the specific growth rate of small centric diatoms (Chaetoceros socialis and Shionodiscus gaarderae, mostly observed in temperate waters) and unidentified small phytoflagellates