HR: 0800h
AN: B41C-0213    [Abstracts]
TI: Effects of Climate Change on Autotrophic Microbial Communities in Lake Qinghai on the Tibetan Plateau, China
AU: * Wang, Y
EM: wang@srel.edu
AF: Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802 United States
AU: Huang, Z
EM: huang@srel.edu
AF: Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802 United States
AU: Schadt, C W
EM: schadtcw@ornl.gov
AF: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 United States
AU: Zhou, J
EM: zhouj@ornl.gov
AF: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 United States
AU: Dong, H
EM: dongh@muohio.edu
AF: Department of Geology, Miami University, Oxford, OH 45056 United States
AU: Yao, S
EM: spyao@nju.edu.cn
AF: Department of Earth Sciences, Nanjing University, Nanjing, 210029 China
AU: Zhang, C
EM: zhang@srel.edu
AF: Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802 United States
AB: Lake Qinghai is located at the northeastern corner of the Tibetan Plateau and at the confluence of the East Asian monsoon, the Winter Monsoon, and the West Indian Monsoon. The goal of this study was to determine how climate change might have affected the microbial communities in the lake ecosystem. A sediment core was taken from the lake at a water depth of about 15 meters. A top sample (0-6 cm depth) and a bottom sample (36-40 cm depth) were studied using a functional-gene microarry method to determine the microbial community patterns that may be influenced by paleoclimatic variations. Based on a mineralogical study, the top sample was deposited within the past 100 years under a humid climate condition and the bottom sample was deposited around 700 years BP under a little ice age climate condition. In both samples, the Calvin-cycle genes were predominant accounting for greater than 90% of total CO2 fixation genes in each sample. Acetyl CoA genes were about the same (4-5%) in the two samples; whereas, the rTCA-cycle genes were twice as high in the top sample (3.6%) as in the bottom sample (1.6%). Rhodobacter sphaeroides and Synechococcus elongatus PCC 6301, two photoautotrophic organisms, were only found in the bottom sample. Other RubisCO genes were found in both samples but had different hybridization intensities; some of them were related to Rhodopseudomonas palustris, Rhodospirillum rubrum, and Rhodobacter capsulatus. The presence of photoautotrophic DNA in the bottom sediment suggests that fossil microorganisms for primary production might have been preserved for the past 700 years in Lake Qinghai sediments. The distinct patterns of gene distribution between these two samples indicate that climate change might have contributed to variation in functional diversity for CO2 fixation in the past 700 years.
DE: 0400 BIOGEOSCIENCES
DE: 0410 Biodiversity
DE: 0428 Carbon cycling (4806)
DE: 0465 Microbiology: ecology, physiology and genomics (4840)
SC: Biogeosciences [B]
MN: Fall Meeting 2005