0 1978, by the American Society of Limnology and Oceanography, Inc. Consumption of dissolved methane in the deep ocean1
Oceanic dissolved methane concentrations are normally in excess of atmospheric equilib-rium values in surface waters but show a rapid decrease with depth. Deep North Atlantic waters have only ca. 30 % of their atmospheric equilibrium values of methane and deep North Pacific waters have only ca. 10%....
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.586.3354 http://www.aslo.org/lo/toc/vol_23/issue_6/1207.pdf |
| Summary: | Oceanic dissolved methane concentrations are normally in excess of atmospheric equilib-rium values in surface waters but show a rapid decrease with depth. Deep North Atlantic waters have only ca. 30 % of their atmospheric equilibrium values of methane and deep North Pacific waters have only ca. 10%. Methane consumption rates calculated from methane anal-yses and water mass ages derived from published data on SII/3He ages, r4C ages, and model calculations show that both methane and oxygen are rapidly consumed in “young ” water but, while oxygen consumption continues at a low rate throughout the deep ocean, methane consumption virtually ceases within about 100 years of isolation from the surface ocean. One of the most interesting features in the oceanic distribution of methane is the presence of marked methane depletions at depth throughout the world’s oceans. Depletions relative to mixed layer con-centrations are also observed for other organic compounds, such as sterols (Ga-gosian 1976) and dissolved combined amino acids (Lee and Bada 1977), and for other dissolved gases, e.g. oxygen and carbon monoxide, possibly N20 (Seiler and Schmidt 1974), and ethylene (Swin-nerton and Linnenbom 1967). Oceanic deep waters are initially formed from surface water. Thus, the presence of lower concentrations of a chemical species in deep waters than in the mixed layer suggests that consump-tion of that species has occurred. The sources for the deep waters of the North Pacific and North Indian Oceans are the |
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