0 1994, by the American Society of Limnology and Oceanography, Inc. Sediment oxygen profiles in a super-oxygenated antarctic lake

• Main Authors: Robert A. Wharton, Michael A. Meyer, Christopher P. Mckay, Rocco L. Mancinelli, George M. Simmons
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Arctic; Hoare; Lake Hoare; McMurdo Dry Valleys; Taylor Valley; The Antarctic; Victoria Land; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.508.337; http://www.aslo.org/lo/toc/vol_39/issue_4/0839.pdf

Perennially ice-covered lakes arc found in the McMurdo Dry Valleys of southern Victoria Land, Antarctica. In contrast to tcmperatc lakes that have diurnal photic periods, antarctic (and arctic) lakes have a yearly photic period. An unusual feature of the antarctic lakes is the occurrence of 0, at super-saturated levels in certain portions of the water column. Here we report the first sediment 0, profiles obtained using a microelectrode from a perennially ice-covered antarctic lake. Sediment cores collected in January and October 1987 from Lake Hoare in Taylor Valley show oxygenation down to 15, and in some cases, 25 cm. The oxygenation of sediments several centimeters below the sediment-water interface is atypical for lake sediments and may be characteristic of perennially ice-covered lakes. There is a significant difference between the observed January and October sediment 0, profiles. Several explanations may account for the difference, including seasonality. A time-dependent model is presented which tests the feasibility of a seasonal cycle resulting from the long photopcriod and benthic primary production in sediments overlain by a highly oxygenated water column. The McMurdo Dry Valleys of southern Vic-toria Land, Antarctica (76”30’-78”3O’S, 160-