Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica
Abstract of the dissertationMicrobial diversity studies in sediments of perennially ice-covered lakes, McMurdo Dry Valleys, AntarcticabyChao TangDoctor of Philosophy, Graduate Program in MicrobiologyUniversity of California, Riverside, October 2009Dr. Brian Lanoil, Chairperson The primary refuge for...
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ftcdlib:oai:escholarship.org/ark:/13030/qt7nr8t55b 2023-05-15T13:58:20+02:00 Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica Tang, Chao Lanoil, Brian D 2009-01-01 application/pdf https://escholarship.org/uc/item/7nr8t55b en eng eScholarship, University of California qt7nr8t55b https://escholarship.org/uc/item/7nr8t55b public Biology Microbiology Ecology Environmental Sciences Antarctica lake sediments McMurdo Dry Valleys microbial diversity etd 2009 ftcdlib 2020-06-06T07:56:03Z Abstract of the dissertationMicrobial diversity studies in sediments of perennially ice-covered lakes, McMurdo Dry Valleys, AntarcticabyChao TangDoctor of Philosophy, Graduate Program in MicrobiologyUniversity of California, Riverside, October 2009Dr. Brian Lanoil, Chairperson The primary refuge for life in the McMurdo Dry Valleys (MCM), Antarctica, is a suite of perennially ice-covered lakes, which are entirely microbial ecosystems. Compared with the microbiology studies in the ice-cover, water column and microbial mats, microbial communities in sediments, which are important components for nutrient cycling and prokaryotic diversity in lacustrine systems, have received considerably less study in these lakes. This is the first study characterizing detailed overall prokaryotic diversity in sediments of MCM lakes. The two selected lakes are Lake Fryxell and west lobe of Lake Bonney (WLB) from Taylor Valley. These two lakes have very distinct benthic geochemistry. Non-culture molecular techniques including clone library and denaturing gradient gel electrophoresis utilizing 16S rRNA gene marker was used. High bacterial diversity and low archaeal diversity was detected in sediments of both lakes; however, the sediment microbial communities are significantly different. Sequences of major bacterial OTUs from WLB sediments exhibited exclusive relatedness to cold environment sequences, suggesting the adaptation to the coldness. Sediment microbial community in Fryxell seemed to be influenced by neighboring marine system and involved in methane cycling. Interspersed layers of microbial mats and terrigenous particles that penetrated through the ice cover largely represent the sediments stratigraphy in MCM lakes. Sedimentation is very slow. Samples from distant sections of the long sediment core of WLB were used to investigate microbial community change over long geologic period. Different origins of sediments (biogenic or terrigenous) and microbial community's evolution were proposed as explanation for the observed differences in microbial community structure from different sections. A fine scale depth profile of surface sediments from Fryxell was studied. There was clearly microbial population change with depths, likely due to geochemistry transition. Sulfate reduction was found to co-exist with methanogenesis in Fryxell sediments with very low sulfate. Sulfate reducing bacteria (SRB) diversity was studied by characterizing dsrAB gene, which encodes for dissimilatory sulfite reductase, the conserved enzyme in all SRB. Two novel dsrAB lineages were discovered. Adaptation of the two dominant clusters to low sulfate condition was suggested; other clusters seemed to be related to marine SRB. Other/Unknown Material Antarc* Antarctica McMurdo Dry Valleys University of California: eScholarship Bonney ENVELOPE(162.417,162.417,-77.717,-77.717) Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) Lake Bonney ENVELOPE(-25.588,-25.588,-80.361,-80.361) Lake Fryxell ENVELOPE(163.183,163.183,-77.617,-77.617) McMurdo Dry Valleys Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Biology Microbiology Ecology Environmental Sciences Antarctica lake sediments McMurdo Dry Valleys microbial diversity |
spellingShingle |
Biology Microbiology Ecology Environmental Sciences Antarctica lake sediments McMurdo Dry Valleys microbial diversity Tang, Chao Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
topic_facet |
Biology Microbiology Ecology Environmental Sciences Antarctica lake sediments McMurdo Dry Valleys microbial diversity |
description |
Abstract of the dissertationMicrobial diversity studies in sediments of perennially ice-covered lakes, McMurdo Dry Valleys, AntarcticabyChao TangDoctor of Philosophy, Graduate Program in MicrobiologyUniversity of California, Riverside, October 2009Dr. Brian Lanoil, Chairperson The primary refuge for life in the McMurdo Dry Valleys (MCM), Antarctica, is a suite of perennially ice-covered lakes, which are entirely microbial ecosystems. Compared with the microbiology studies in the ice-cover, water column and microbial mats, microbial communities in sediments, which are important components for nutrient cycling and prokaryotic diversity in lacustrine systems, have received considerably less study in these lakes. This is the first study characterizing detailed overall prokaryotic diversity in sediments of MCM lakes. The two selected lakes are Lake Fryxell and west lobe of Lake Bonney (WLB) from Taylor Valley. These two lakes have very distinct benthic geochemistry. Non-culture molecular techniques including clone library and denaturing gradient gel electrophoresis utilizing 16S rRNA gene marker was used. High bacterial diversity and low archaeal diversity was detected in sediments of both lakes; however, the sediment microbial communities are significantly different. Sequences of major bacterial OTUs from WLB sediments exhibited exclusive relatedness to cold environment sequences, suggesting the adaptation to the coldness. Sediment microbial community in Fryxell seemed to be influenced by neighboring marine system and involved in methane cycling. Interspersed layers of microbial mats and terrigenous particles that penetrated through the ice cover largely represent the sediments stratigraphy in MCM lakes. Sedimentation is very slow. Samples from distant sections of the long sediment core of WLB were used to investigate microbial community change over long geologic period. Different origins of sediments (biogenic or terrigenous) and microbial community's evolution were proposed as explanation for the observed differences in microbial community structure from different sections. A fine scale depth profile of surface sediments from Fryxell was studied. There was clearly microbial population change with depths, likely due to geochemistry transition. Sulfate reduction was found to co-exist with methanogenesis in Fryxell sediments with very low sulfate. Sulfate reducing bacteria (SRB) diversity was studied by characterizing dsrAB gene, which encodes for dissimilatory sulfite reductase, the conserved enzyme in all SRB. Two novel dsrAB lineages were discovered. Adaptation of the two dominant clusters to low sulfate condition was suggested; other clusters seemed to be related to marine SRB. |
author2 |
Lanoil, Brian D |
format |
Other/Unknown Material |
author |
Tang, Chao |
author_facet |
Tang, Chao |
author_sort |
Tang, Chao |
title |
Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
title_short |
Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
title_full |
Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
title_fullStr |
Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
title_full_unstemmed |
Microbial Diversity Studies in Sediments of Perennially Ice-covered Lakes, McMurdo Dry Valleys, Antarctica |
title_sort |
microbial diversity studies in sediments of perennially ice-covered lakes, mcmurdo dry valleys, antarctica |
publisher |
eScholarship, University of California |
publishDate |
2009 |
url |
https://escholarship.org/uc/item/7nr8t55b |
long_lat |
ENVELOPE(162.417,162.417,-77.717,-77.717) ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(-25.588,-25.588,-80.361,-80.361) ENVELOPE(163.183,163.183,-77.617,-77.617) ENVELOPE(163.000,163.000,-77.617,-77.617) |
geographic |
Bonney Fryxell Lake Bonney Lake Fryxell McMurdo Dry Valleys Taylor Valley |
geographic_facet |
Bonney Fryxell Lake Bonney Lake Fryxell McMurdo Dry Valleys Taylor Valley |
genre |
Antarc* Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys |
op_relation |
qt7nr8t55b https://escholarship.org/uc/item/7nr8t55b |
op_rights |
public |
_version_ |
1766266571852873728 |