title: Response of an antarctic lake heterotrophic community to high dissolved oxygen.
abstract: The upper waters of Lake Hoare, Antarctica, contain dissolved oxygen at about three times the normal saturation (>/=42 mg liter). The response of the heterotrophic plankton community to this high dissolved oxygen was evaluated by the criteria of CFU and d-[U-C]glucose assimilated-respired. High dissolved oxygen was not inhibitory to d-[U-C]glucose assimilation-respiration compared with normal atmospheric dissolved oxygen in Lake Hoare water. The d-[U-C]glucose was assimilated and respired optimally at 12 degrees C in Lake Hoare. The d-[U-C]glucose assimilated-respired in the upper saturated atmospheric dissolved oxygen waters of Mountain Lake, Va., was inhibited in contrast to Lake Hoare (P < 0.05). CFU formation was inhibited in both lakes. CFU represent <1% of the fluorochrome-stained direct counts in Lake Hoare. Lake Hoare planktobacteria are smaller than the planktobacteria in Mountain Lake. ATP size fractionation revealed that 39% of the ATP biomass was <0.5 mum in Lake Hoare.
authors.affiliation: Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061.
authors.forename: A T
authors.initials: AT
authors.lastname: Mikell
authors.forename: B C
authors.initials: BC
authors.lastname: Parker
authors.forename: G M
authors.initials: GM
authors.lastname: Simmons