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Seasonal variation of CO 2 saturation in the Gulf of Bothnia: Indications of marine net heterotrophy
Author(s) -
Algesten Grete,
Wikner Johan,
Sobek Sebastian,
Tranvik Lars J.,
Jansson Mats
Publication year - 2004
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2004gb002232
Subject(s) - sink (geography) , environmental science , bay , oceanography , new production , bacterioplankton , primary production , seasonality , heterotroph , plankton , atmosphere (unit) , photic zone , pycnocline , water column , phytoplankton , nutrient , geology , biology , ecology , paleontology , physics , cartography , ecosystem , bacteria , geography , thermodynamics
Seasonal variation of p CO 2 and primary and bacterioplankton production were measured in the Gulf of Bothnia during an annual cycle. Surface water was supersaturated with CO 2 on an annual basis, indicating net heterotrophy and a source of CO 2 to the atmosphere. However, the Gulf of Bothnia oscillated between being a sink and a source of CO 2 over the studied period, largely decided by temporal variation in bacterial respiration (BR) and primary production (PP) in the water column above the pycnocline. The calculated annual respiration‐production balance (BR‐PP) was very similar to the estimated CO 2 emission from the Gulf of Bothnia, which indicates that these processes were major determinants of the exchange of CO 2 between water and atmosphere. The southern basin (the Bothnian Sea) had a lower net release of CO 2 to the atmosphere than the northern Bothnian Bay (7.1 and 9.7 mmol C m −2 d −1 , respectively), due to higher primary production, which to a larger extent balanced respiration in this basin.