Soil organic C (SOC) levels were determined to a depth of 100 cm for the nine units designated on a 1957 1:20000 soil map of Barrow, AK prepared by J.V. Drew. The legend was updated by converting Drew's map units into the recently adopted Gelisol order in U.S. soil taxonomy and field verified. The SOC varied from 2.5 kg m−3 in modern beach sediments to >73 kg m−3 in Typic Sapristels in high‐centered, ice‐wedge polygons developed in reworked organic‐rich lake sediments. The SOC averaged 50 kg m−3 for the entire 64‐km2 area (excluding open water). Considerable variability in SOC exists within individual soil map units. For example, SOC levels in a Typic Aquiturbel (formerly classified as a Meadow Tundra, Normal Phase soil) ranged from 24 to 109 kg m−3 Substantial variation in SOC occurs within individual patterned‐ground units. For a high‐centered, ice‐wedge polygon with a diameter of 15 m, SOC levels are 24, 32, and 64 kg m−3 for the wedge trough, rim, and center, respectively. In a low‐centered, ice‐wedge polygon, SOC levels are 28 and 83 kg m−3 for the trough and center. The variation in SOC within soil map units and individual patterned‐ground units is due primarily to differences in the amount of ground ice. Active‐layer thickness varies within and between soil map units, ranging from 31 cm in Typic Sapristels to >100 cm in modern beach sediments. About 47% of the SOC in the upper meter of soil was in the active layer at the time of sampling; the remainder occurring in frozen ground, much of it meeting the definition of permafrost. Some of the SOC originates from past reworking of organic‐rich lake sediments. Carbon stocks in near‐surface permafrost may be of global significance and should be inventoried in other tundra regions.
Douglas and Tedrow (1960) were the first to report calcareous tundra soils in northern Alaska. Soils adjacent to the Sagavanirktok River were consistently alkaline. Calcareous soils derived from loess and lacustrine materials occur throughout the Prudhoe Bay region (Everett, 1975; Everett and Parkinson, 1977; Parkinson, 1978). Walker and Everett (1991) collected soil samples along a 20-km loess gradient downwind of the Sagavanirktok River, showing the effects of loess deposition on particlesize distribution, pH, and other soil properties. They proposed that early minerotrophic stages of tundra succession in northern Alaska are maintained by loess blown off the Sagavarnirktok, Canning, and other large braided rivers. The mechanism for soil acidification on loess-derived soils in the arctic foothills is not completely understood. Past studies suggest that plant succession plays a large role in the distribution of moist nonacidic and moist acidic tundra (Walker et al., 1995; Walker and Walker, 1996). This study compares and contrasts silt-rich soils under moist nonacidic tundra and moist acidic tundra over a much larger area than previous studies and illustrates the importance of cryoturbation in maintaining moist nonacidic tundra. The contribution is part of the Arctic Flux Study, an investigation into land-atmosphere-ice interactions in arctic Alaska (Weller et al., 1995).
Pain continues to be a well-known complication of cardiac surgery in the postoperative period and intravenous opioid analgesia has traditionally been employed to manage cardiac surgical pain. However, both components have contributed to a multitude of undesirable adverse effects which can further exacerbate delays in recovery. Often overlooked in the analgesic plan, chest tube pain contributes significantly to the overall postoperative pain from cardiac surgery. Novel regional anesthetic blocks have shown great promise as analgesic adjuncts for cardiothoracic anesthesia but preliminary investigations focus primarily on management of sternotomy pain. Reduction of chest tube pain should be considered while implementing regional blocks to control surgical pain. This study presents a case where the rectus sheath block minimized chest tube pain after aortic valve replacement in conjunction with intercostal nerve blocks and a multimodal analgesic plan.
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