. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering "04 < 12 16 20 24 TIME (hrs) STA Ebb 37. 12 16 20 24 28 32 36 TIME (hrs) Figure 27-4. Short-term variability of dissolved methane at stations 46 (a) and Ebb 37 (b) in 1975. tion of methane. In the absence of significant micro- bial oxidative processes, methane dissolved in the shallow brackish waters of the lagoon would be transported through the entrance by tidal pumping (Barsdate et al. 1974). Because the air-sea exchange of methane is relati
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering "04 < 12 16 20 24 TIME (hrs) STA Ebb 37. 12 16 20 24 28 32 36 TIME (hrs) Figure 27-4. Short-term variability of dissolved methane at stations 46 (a) and Ebb 37 (b) in 1975. tion of methane. In the absence of significant micro- bial oxidative processes, methane dissolved in the shallow brackish waters of the lagoon would be transported through the entrance by tidal pumping (Barsdate et al. 1974). Because the air-sea exchange of methane is relative- ly slow, advection of methane-rich water could be traced east along the Alaska Peninsula for nearly 200 km. Although a cyclonic mean flow in the coastal water does not appear to dominate the shelf salt budget (Coachman and Charnell 1979), a weak coastal current exists along the peninsula (Kinder and Schumacher, Chapter 5, this volume). The surface distribution of methane in July, not unlike temperature, delineates quite sharply the hy- drographic domains over the shelf. Near the shore in water depths less than about 50 m, the concentra- tions of methane were everywhere greater than 100 nl/1 and reflected increased production relative to the previous fall. The source of the methane is not known precisely, but would include coastal sources as well as in-situ production from both bottom sedi- ments and the water column. The Kuskokwim River may also be a significant source of methane as suggested by the high concen- trations (> 400 nl/1) found near Cape Newenham. The Kuskokwim River was not sampled for dissolved hydrocarbons, but the Yukon River plume was sam- pled in July 1979 and found to contain concentra- tions of methane in excess of 2,000 nl/1. We would expect the lower reaches of the two rivers to be similar in dissolved methane content, since their lower drainage basins are similar. As mentioned. Please note that these images are extracted from scanned page images th
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