The effect of dust on phytoplankton communities of Nuevo Gulf

AUGUSTO CÉSAR CRESPI ABRIL; SONIA BRUGEL; RODRIGO HERNÁNDEZ-MORESINO; LUCIA EPHERRA; RODRIGO GONÇALVES; ANTONELLA DE CIAN; JOANNA PACKOWSKA; GASPAR SORIA; LOURDES BARKI; LEANDRO GETINO MAMET; ELENA BARBIERI; AGNETA ANDERSSON; FLAVIO PAPARAZZO; ANTONELA MARTELLI

Bremen

Conferencia; International Conference for Young Marine Researchers: ICYMARE; 2019

University of Bremen

Atmospheric dust is a source of micro- and macronutrients to the ocean and playsan important role in shaping marine biogeochemical cycles and possibly in globalclimate by promoting CO2 sequestration. Despite Patagonia being the major sourceof aeolian dust in the southern part of the Atlantic Ocean, responses of plankton communities to dust input have not yet been studied. The aim of our study is to determine the effect of Patagonian dust on coastal phytoplankton communities in field and experimental studies. Biweekly sampling was performed at a fixed station located in front of Puerto Madryn city in Nuevo Gulf to study the dynamics of phytoplankton communities influenced by atmospheric and oceanographic conditions of this coastal system. Additionally, a microcosm incubation was carried out in situ next to the sampling station during the summer period. The aim of the experiment was to determine the response of a natural phytoplankton community to the addition of dust collected during spring of 2018. It was run for 5 days with three treatments (in triplicates): control (without dust addition), low dust concentration (DustL , 0.2 mg/L) and high dust concentration (DustH, 1 mg/L). Changes in variables of nutrients (dissolved inorganic phosphorus, dissolved inorganic nitrogen and silicate), chlorophyll a and dissolved organic carbon (DOC) were measured over time. As preliminary results, highest concentrations of nitrate+nitrite and DOC were found in DustH treatment, while DustL treatment did not significantly differ from the control. DustL showed higher concentrations of chlorophyll a than DustH and the control treatment. As a brief discussion we estimate that atmospheric Patagonian dust adds dissolved macronutrients to the seawater, and there may be other processes as toxicity or grazing that could be negatively affecting the physiology of the phytoplankton community.