The effect of dust on phytoplankton communities of Nuevo Gulf

ANTONELLA DE CIAN; AUGUSTO C. CRESPI-ABRIL; ELENA S. BARBIERI; JOANNA M. PACZKOWSKA; SONIA BRUGEL; AGNETA ANDERSSON; GASPAR SORIA; RODRIGO D. HERNÁNDEZ MORESINO; FLAVIO E. PAPARAZZO; LOURDES BARKI; LUCÍA EPHERRA; ANTONELA MARTELLI; LEANDRO GETINO MAMET; RODRIGO J. GONÇALVES

Bremen (Alemania)

Conferencia; International conference for YOUNG marine researchers 2019; 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 planktoncommunities to dust input have not yet been studied. The aim of our study is todetermine the effect of Patagonian dust on coastal phytoplankton communities infield and experimental studies. Biweekly sampling was performed at a fixed stationlocated in front of Puerto Madryn city in Nuevo Gulf to study the dynamics ofphytoplankton communities influenced by atmospheric and oceanographicconditions of this coastal system. Additionally, a microcosm incubation was carriedout in situ next to the sampling station during the summer period. The aim of theexperiment was to determine the response of a natural phytoplankton community tothe addition of dust collected during spring of 2018. It was run for 5 days with threetreatments (in triplicates): control (without dust addition), low dust concentration(DustL, 0.2 mg/L) and high dust concentration (DustH, 1 mg/L). Changes in variablesof nutrients (dissolved inorganic phosphorus, dissolved inorganic nitrogen andsilicate), chlorophyll a and dissolved organic carbon (DOC) were measured overtime. As preliminary results, highest concentrations of nitrate+nitrite and DOC werefound in DustH treatment, while DustL treatment did not significantly differ from thecontrol. Dust L showed higher concentrations of chlorophyll a than DustH and thecontrol treatment. As a brief discussion we estimate that atmospheric Patagoniandust adds dissolved macronutrients to the seawater, and there may be otherprocesses as toxicity or grazing that could be negatively affecting the physiology ofthe phytoplankton community.