CESIMAR - CENPAT   25625
CENTRO PARA EL ESTUDIO DE SISTEMAS MARINOS
Unidad Ejecutora - UE
artículos
Título:
Major differences in dissolved organic matter characteristics and bacterial processing over an extensive brackish water gradient, the Baltic Sea
Autor/es:
PACZKOWSKA, JOANNA; ANDERSSON, AGNETA; ROWE, OWEN F.; FIGUEROA, DANIELA; DINASQUET, JULIE; RIEMANN, LASSE
Revista:
MARINE CHEMISTRY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2018
ISSN:
0304-4203
Resumen:
Dissolved organic matter (DOM) in marine waters is a complex mixture ofcompounds and elements that contribute substantially to the global carbon cycle. Thelarge reservoir of dissolved organic carbon (DOC) represents a vital resource forheterotrophic bacteria. Bacteria can utilise, produce, recycle and transformcomponents of the DOM pool, and the physicochemical characteristics of this poolcan directly influence bacterial activity; with consequences for nutrient cycling andprimary productivity. In the present study we explored bacterial transformation ofnaturally occurring DOM across an extensive brackish water gradient in the BalticSea. Highest DOC utilisation (indicated by decreased DOC concentration) wasrecorded in the more saline southerly region where waters are characterised by moreautochthonous DOM. These sites expressed the lowest bacterial growth efficiency(BGE), whereas in northerly regions, characterised by higher terrestrial andallochthonous DOM, the DOC utilisation was low and BGE was highest. Bacterialprocessing of the DOM pool in the south resulted in larger molecular weightcompounds and compounds associated with secondary terrestrial humic matter beingdegraded, and a processed DOM pool that was more aromatic in nature andcontributed more strongly to water colour; while the opposite was true in the north.Nutrient concentration and stoichiometry and DOM characteristics affected bacterialsctivity, including metabolic status (BGE), which influenced DOM transformations.Our study highlights dramatic differences in DOM characteristics and microbialcarbon cycling in sub-basins of the Baltic Sea. These findings are critical for ourunderstanding of carbon and nutrient biogeochemistry, particularly in light of climatechange scenarios.