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. 148 272-284

Subject Categories

Oceanography, Hydrology, Water Resources

DOI

10.1016/j.jmarsys.2015.03.002