Dynamics of pCO2 and related air-ice CO2 fluxes in the Arctic coastal zone (Amundsen Gulf, Beaufort Sea)

in Journal of Geophysical Research. Oceans (2012), 117(C00G10),

We present an Arctic seasonal survey of carbon dioxide partial pressure (pCO2) dynamics within sea ice brine and related air-ice CO2 fluxes. The survey was carried out from early spring to the beginning ... [more ▼]

We present an Arctic seasonal survey of carbon dioxide partial pressure (pCO2) dynamics within sea ice brine and related air-ice CO2 fluxes. The survey was carried out from early spring to the beginning of summer in the Arctic coastal waters of the Amundsen Gulf. High concentrations of pCO2 (up to 1834 matm) were observed in the sea ice in early April as a consequence of concentration of solutes in brines, CaCO3 precipitation and microbial respiration. CaCO3 precipitation was detected through anomalies in total alkalinity (TA) and dissolved inorganic carbon (DIC). This precipitation seems to have occurred in highly saline brine in the upper part of the ice cover and in bulk ice. As summer draws near, the ice temperature increases and brine pCO2 shifts from a large supersaturation (1834 matm) to a marked undersaturation (down to almost 0 matm). This decrease was ascribed to brine dilution by ice meltwater, dissolution of CaCO3 and photosynthesis during the sympagic algal bloom. The magnitude of the CO2 fluxes was controlled by ice temperature (through its control on brine volume and brine channels connectivity) and the concentration gradient between brine and the atmosphere. However, the state of the ice-interface clearly affects air-ice CO2 fluxes. [less ▲]

Sea ice contribution to the air-sea CO2 exchange in the Arctic and Southern Oceans

in Tellus : Series B (2011), 63(5), 823-830

Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO2 and the subsequent effect on air–sea CO2 exchange have received little ... [more ▼]

Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO2 and the subsequent effect on air–sea CO2 exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air–sea CO2 exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO2 uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO2 uptake in ice-free polar seas. This sea-ice driven CO2 uptake has not been considered so far in estimates of global oceanic CO2 uptake. Net CO2 uptake in sea-ice–covered oceans can be driven by; (1) rejection during sea–ice formation and sinking of CO2-rich brine into intermediate and abyssal oceanic water masses, (2) blocking of air–sea CO2 exchange during winter, and (3) release of CO2-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO2 drawdown during primary production in sea ice and surface oceanic waters. [less ▲]

Temporal evolution of biogeochemical properties of landfast sea ice at Barrow (Alaska)

Poster (2011, March)

Sea ice and snow cover characteristics during the winter-spring transition in the Bellingshausen Sea: an overview of SIMBA 2007

in Deep-Sea Research Part II, Topical Studies in Oceanography (2011), 58(9-10), 10191038

The Sea Ice Mass Balance in the Antarctic (SIMBA) experiment was conducted from the RVIB N.B. Palmer in September and October 2007 in the Bellingshausen Sea in an area recently experiencing considerable ... [more ▼]

The Sea Ice Mass Balance in the Antarctic (SIMBA) experiment was conducted from the RVIB N.B. Palmer in September and October 2007 in the Bellingshausen Sea in an area recently experiencing considerable changes in both climate and sea ice cover. Snow and ice properties were observed at 3 short-term stations and a 27-day drift station (Ice Station Belgica, ISB) during the winter-spring transition. Repeat measurements were performed on sea ice and snow cover at 5 ISB sites, each having different physical characteristics, with mean ice (snow) thicknesses varying from 0.6m (0.1m) to 2.3m (0.7m). Ice cores retrieved every five days from 2 sites and measured for physical, biological, and chemical properties. Three ice mass-balance buoys (IMBs) provided continuous records of snow and ice thickness and temperature. Meteorological conditions changed from warm fronts with high winds and precipitation followed by cold and calm periods through four cycles during ISB. The snow cover regulated temperature flux and controlled the physical regime in which sea ice morphology changed. Level thin ice areas had little snow accumulation and experienced greater thermal fluctuations resulting in brine salinity and volume changes, and winter maximum thermodynamic growth of ~0.6m in this region. Flooding and snow-ice formation occurred during cold spells in ice and snow of intermediate instead nearly isothermal, highly permeable ice persisted. In spring, short-lived cold air episodes did not effectively penetrate the sea ice nor overcome the effect of ocean heat flux, thus favoring net ice thinning from bottom melt over ice thickening from snow-ice growth, in all cases. These warm ice conditions were consistent with regional remote sensing observations of earlier ice breakup and a shorter sea ice season, more recently observed in the Bellingshausen Sea. [less ▲]

Belgian IPY Symposium 'The contribution of Belgian research to the achievements of the International Polar Year 2007-9

Book published by Universa Press (2010)

Air-sea ice CO2 fluxes measurement with eddy-covariance micrometeorological technique

Conference (2010)

Iron study during a time series in the western Weddell pack ice

in Marine Chemistry (2008), 108(1-2), 85-95

Samples of sea ice, snow, brine and underlying seawater were collected in the western Weddell pack ice at the ISPOL drifting station (Ice Station POLarstern, 68 degrees S/55 degrees W) in spring-summer ... [more ▼]

Samples of sea ice, snow, brine and underlying seawater were collected in the western Weddell pack ice at the ISPOL drifting station (Ice Station POLarstern, 68 degrees S/55 degrees W) in spring-summer period (November 2004-January 2005). Total-dissolvable, dissolved and particulate Fe concentrations in the sea ice environment were determined every 5 days during the time series, together with relevant physical, chemical and biological parameters. From 29 November to 30 December, a decrease in all forms of Fe measured was observed, likely to be the result of enhanced ice permeability as summer proceeds. At the beginning of the time series, melting of the upper ice layer took place together with brine drainage process. This would enable the seeding of Fe from the ice matrix towards the upper water column below. 70% of this Fe was supplied during the first 10 days of the survey, while the ice cover is still present. Flux estimates from the sampled area furthermore highlight the relevant role of the pack ice in the biogeochemical cycle of Fe in the western Weddell Sea. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]