Changes in gross oxygen production, net oxygen production, and air-water gas exchange during seasonal ice melt in Whycocomagh Bay, a Canadian estuary in the Bras d'Or Lake system

Cara C. Manning, Rachel H.R. Stanley, David P. Nicholson, Brice Loose, Ann Lovely, Peter Schlosser, Bruce G. Hatcher

Research output: Contribution to journalArticle

Abstract

Sea ice is an important control on gas exchange and primary production in polar regions. We measured net oxygen production (NOP) and gross oxygen production (GOP) using near-continuous measurements of the O2/Ar gas ratio and discrete measurements of the triple isotopic composition of O2, during the transition from ice-covered to ice-free conditions, in Whycocomagh Bay, an estuary in the Bras d'Or Lake system in Nova Scotia, Canada. The volumetric gross oxygen production was 5.4+2.8-1.6 mmol O2 m-3 d-1, similar at the beginning and end of the time series, and likely peaked at the end of the ice melt period. Net oxygen production displayed more temporal variability and the system was on average net autotrophic during ice melt and net heterotrophic following the ice melt. We performed the first field-based dual tracer release experiment in icecovered water to quantify air-water gas exchange. The gas transfer velocity at > 90% ice cover was 6% of the rate for nearly ice-free conditions. Published studies have shown a wide range of results for gas transfer velocity in the presence of ice, and this study indicates that gas transfer through ice is much slower than the rate of gas transfer through open water. The results also indicate that both primary producers and heterotrophs are active in Whycocomagh Bay during spring while it is covered in ice.

Original languageEnglish (US)
Pages (from-to)3351-3376
Number of pages26
JournalBiogeosciences
Volume16
Issue number17
DOIs
StatePublished - Sep 5 2019

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gas exchange
ice
estuaries
estuary
melt
lakes
air
oxygen
lake
water
gases
gas
oxygen production
Polar Regions
polar region
ice cover
open water
heterotrophs
Nova Scotia
primary production

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes

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Changes in gross oxygen production, net oxygen production, and air-water gas exchange during seasonal ice melt in Whycocomagh Bay, a Canadian estuary in the Bras d'Or Lake system. / Manning, Cara C.; Stanley, Rachel H.R.; Nicholson, David P.; Loose, Brice; Lovely, Ann; Schlosser, Peter; Hatcher, Bruce G.

In: Biogeosciences, Vol. 16, No. 17, 05.09.2019, p. 3351-3376.

Research output: Contribution to journalArticle

Manning, Cara C. ; Stanley, Rachel H.R. ; Nicholson, David P. ; Loose, Brice ; Lovely, Ann ; Schlosser, Peter ; Hatcher, Bruce G. / Changes in gross oxygen production, net oxygen production, and air-water gas exchange during seasonal ice melt in Whycocomagh Bay, a Canadian estuary in the Bras d'Or Lake system. In: Biogeosciences. 2019 ; Vol. 16, No. 17. pp. 3351-3376.
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