Seasonal DOC accumulation in the Black Sea: a regional explanation for a general mechanism

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Oui
Statut de publication : Publié
Année de publication : 2002
Auteurs (10) : CAUWET G DELIAT G KRASTEV A SHTEREVA G BECQUEVORT S LANCELOT C MOMZIKOFF A SALIOT A COCIASU A POPA L
Revue scientifique : Marine Chemistry
Volume : 79
Fascicule :
Pages : 193-205
DOI : 10.1016/S0304-4203(02)00064-6
URL : -
Abstract : During three cruises in the Black Sea, organised in July 1995 and
April-May 1997, biological and chemical parameters that can influence
the carbon budget were measured in the water column on the NW shelf,
particularly in the mixing zone with Danube River waters. We observed in
early spring (end of April-May) conditions an important input of
freshwater organisms that enhanced the microbial activity in the low
salinity range. High bacterial activity regenerates nitrogen in the form
of nitrates, but is also responsible for an important consumption of
ammonium and phosphate, leading to a high N/P ratio and a strong deficit
in phosphorus. The consequence is a limitation of phytoplankton
development but also a production of carbohydrates that accumulate all
along the salinity gradient. These mechanisms are responsible for a
seasonal accumulation of dissolved organic carbon (DOC) that increases
from 210 muM in winter to about 280 muM in summer. All this excess DOC
disappears during winter, probably degraded by bacterial activity. The
degradation of carbon-rich organic matter increases the phosphorus
demand by bacteria bringing limitation to phytoplankton primary
production. (C) 2002 Published by Elsevier Science B.V.
Mots-clés : dissolved organic carbon; carbon cycling; accumulation; productivity; microbial loop; nutrients consumption; carbohydrates; Black Sea; Danube; mixing zone
Commentaire : 6th Model Estuary Symposium: Large Deltas and their Impact on Coastal
Zones, ISPRA, ITALY, JUL 05-07, 2000
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Citation :
Cauwet G, Deliat G, Krastev A, Shtereva G, Becquevort S, Lancelot C, Momzikoff A, Saliot A, Cociasu A, Popa L (2002) Seasonal DOC accumulation in the Black Sea: a regional explanation for a general mechanism. Mar Chem 79: 193-205 | doi: 10.1016/S0304-4203(02)00064-6