Factors shaping microbial community structure and dissolved organic matter composition during spring in the San Jorge Gulf

AUGUSTO C. CRESPI-ABRIL; GABRIELA N. WILLIAMS; AGNETA ANDERSSON; JOANNA M. PACZKOWSKA; ANTONELLA DE CIAN; SONIA BRUGEL; FLAVIO E. PAPARAZZO; REGINA PIERATTINI MARTÍNEZ; RODRIGO J. GONÇALVES

Seminario; VI SEMINARIO GOLFO SAN JORGE; 2019

CCT CONICET-CENPAT

Interactionbetween phytoplankton and bacteria is one of the most importantrelationship in aquatic ecosystems, shaping carbon and nutrientscycling and regulating biological productivity. Phytoplankton are themajor primary producers responsible for almost half of global netprimary production supporting over 95% of marine food web. Duringphotosynthesis, phytoplankton convert atmospheric carbon dioxide(CO2)into organic matter (OM) in the presence of sunlight and dissolvedinorganic nutrients. Bacteria as heterotrophs obtains essentialcarbon for growth by consuming labile organic carbon released by thephytoplankton (autochthonous) or deliver from external sources(allochthonous) via rivers, groundwater or atmospheric deposition.Phytoplankton-produced organic matter contains mainlylow-molecular-weight (LMW) compounds such as amino acids, simplesugars which can be directly assimilated by heterotrophic bacteria,while allochthonous organic matter is characterized by highercontribution of high-molecular-weight (HMW) e.g. proteins which needto be transformed to more simple molecular through various enzymaticand abiotic (e.g., photolysis) processes. The aim of this project wasto study factors governing microbial community structure and examinethe source and composition of the dissolved organic matter in the SanJorge Gulf using absorbance and fluorescence spectroscopy. Sampleswere collected during Pampa Azul campaign in October/November 2017.p { margin-bottom: 0.25cm; direction: ltr; line-height: 115%; text-align: left; background: transparent none repeat scroll 0% 0%; }