University of Tasmania
Browse

File(s) under permanent embargo

pCO2 distributions and air-water CO2 fluxes in the Columbia River estuary

journal contribution
posted on 2023-05-17, 22:56 authored by Evans, W, Hales, B, Peter StruttonPeter Strutton
Sources of time and space variability in the distributions of surface water carbon dioxide partial pressure (pCO2) and airewater CO2 flux were quantified in the Columbia River estuary (CRE) during five cruises in spring, summer and autumn 2007/08. The CRE is an upwelling margin river-dominated mesotidal system that is an estuary class not represented in global flux compilations. Data from the CRE show instances of pCO2 under and oversaturation with respect to the atmosphere during every season in association with tidal, wind, biological and storm-driven sources of variability. On average the CRE is a sink for atmo- spheric CO2 during spring and a source during summer and autumn, with large positive airewater CO2 fluxes during the snowmelt freshet coinciding with the functional transition in the estuary. It is hypothesized here that interannual variability in size of the snowmelt freshet largely influences the extent of springtime CO2 uptake in the CRE, and subsequently the magnitude of net annual CO2 emission from the estuary. Data collected during an autumn storm show that large fluxes can drop quickly, even in the presence of high gas transfer velocities, because of rapid CO2 exchange with the atmosphere in this weakly buffered system. Combining seasonal observations of CO2 exchange with an assumption of winter conditions, we estimate that the net annual emission from the CRE is approximately 1 mol C m-2 yr-1. The airewater CO2 fluxes reported here are the first from an upwelling margin river-dominated meso- tidal estuary, and the estimate of net annual exchange is substantially lower than those from other tidal and/or large river systems represented in global flux compilations.

History

Publication title

Estuarine, Coastal and Shelf Science

Volume

117

Pagination

260-272

ISSN

0272-7714

Department/School

Institute for Marine and Antarctic Studies

Publisher

Academic Press Ltd Elsevier Science Ltd

Place of publication

24-28 Oval Rd, London, England, Nw1 7Dx

Rights statement

Copyright 2012 Elsevier

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC