Continuous long-term observations of the carbonate system dynamics in the water column of a temperate fjord
Journal article, 2015
A cabled underwater observatory with more than 30 sensors delivering data in real-time was used to study the dynamics of the upper pelagic carbonate system of the Koljo Fjord, western Sweden, from September to April during two consecutive years (2011-2012 and 2012-2013). In the dynamic upper ca 15 m of the water column, salinity and temperature varied by up to 10 and 20 degrees C throughout the recorded periods, respectively. Partial pressure of CO2 (pCO(2)), measured with newly developed optical sensors (optodes) at three water depths (5, 9.6 and 12.6 m), varied between 210-940 mu atm, while O-2 varied between 80-470 mu mol/L. Redfield scaled graphs (Delta O-2:Delta DIC = -1.30), in which DIC was derived from pH or pCO(2) and salinity-derived alkalinity (A(Tsal)), and oxygen was measured by the sensors, were used as a tool to assess timing and occurrence of different processes influencing the dynamics of these parameters. Distinctive short-term variations of pCO(2) and O-2 were induced by either tidal oscillations, wind-driven water mass transport in the mixed layer or occasional transport of deep-basin water from below the thermo/halodine to the surface layer. Intensified air-sea gas exchange during short storm events was usually followed by stabilization of gas-related parameters in the water column, such as O-2 concentration and pCO(2), on longer time-scales characteristic for each parameter. Biological processes including organic matter degradation in late summer/autumn and primary production in early spring were responsible for slower and gradual seasonal changes of pCO(2) and O-2. Net primary production (NPP) rates in the Koljo Fjord were quantified to be 1.79 and 2.10 g C m(-2) during the spring bloom periods in 2012 and 2013, respectively, and ratios of 02 production:DIC consumption during the same periods were estimated to be -1.21 +/- 0.02 (at 5 m depth in 2013), -1.51 +/- 0.02 (at 12.6 m in 2012) and -1.95 +/- 0.05 (at 9.6 m in 2013). These ratios are discussed and compared to previously reported 02:C ratios during primary production. (C) 2015 Elsevier B.V. All rights reserved.
Marine & Freshwater Biology
SEA
PARTIAL-PRESSURE
PROFILING FLOAT
V40
Carbonate system of seawater
TIME-SERIES
TOTAL INORGANIC CARBON
ORGANIC-MATTER
1995
pCO(2)
CORE WAVE-GUIDE
P444
GRANDPRE MD
1991
Long-term in situ measurements
Oceanography
Redfield ratio
LIFETIME-BASED OPTODE
IGEBRANDT A
Multidisciplinary
NPP rates
Geosciences
LIMNOLOGY AND OCEANOGRAPHY
LIMNOLOGY AND OCEANOGRAPHY
V36
P969
DISSOCIATION-CONSTANTS
BALTIC
NORTH-SEA
Author
Dariia Atamanchuk
University of Gothenburg
Mikhail Kononets
University of Gothenburg
P. J. Thomas
J. Hovdenes
Anders Tengberg
University of Gothenburg
Per Hall
University of Gothenburg
Journal of Marine Systems
0924-7963 (ISSN)
Vol. 148 272-284Subject Categories
Oceanography, Hydrology, Water Resources
DOI
10.1016/j.jmarsys.2015.03.002