DSpace at EWHA: A study of Wetland Vegetation and Microbial Communities under Elevated CO₂, Warming, and Drought

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DC Field	Value	Language
dc.contributor.author	김선영	-
dc.creator	김선영	-
dc.date.accessioned	2016-08-25T11:08:14Z	-
dc.date.available	2016-08-25T11:08:14Z	-
dc.date.issued	2007	-
dc.identifier.other	OAK-000000027951	-
dc.identifier.uri	https://dspace.ewha.ac.kr/handle/2015.oak/187607	-
dc.identifier.uri	http://dcollection.ewha.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000027951	-
dc.description.abstract	Anthropogenic activities have increased the concentration of atmospheric CO₂, temperature and the frequency of drought in the earth. Those climate changes can affect wetlands which play a pivotal role in global biogeochemical cycles. The main objective of this thesis is to elucidate the effects of future environmental condition on wetland biogeochemistry. Elevated CO₂ did not affect vegetation growth of all species, but root-derived DOC and phenolics increased in the soil. Higher amount of DOC and phenolics were released under elevated CO₂ with enriched N supply and low N treatments, respectively. Enzyme activities were positively correlated with DOC in soil, but negatively with phenolics or the ratio of phenolics to DOC. Soil respiration either decreased or maintained under elevated CO₂ and had a negative correlation with phenolics in the soil. Elevated CO₂ did not affect biomass under control salinity conditions (25 ppt). However, greater DOC and phenolics concentrations were measured in porewaters under elevated CO₂. In contrast, halophytes grown in higher salinity conditions (35 ppt) showed larger growth stimulation under elevated CO₂ compared to ambient air. The salt marsh harbored microbial communities with differing abundance: bacteria > denitrifiers > methanogens > SRB. Only the abundance of SRB increased with elevated CO₂ and high salinity, respectively. High salinity led to the shift in the composition of SRB and denitrifiers, while elevated CO₂ did not affect the microbial communities. Positive correlations between abundance of SRB and phenolics (or phenolic-C ratio) and between salinity and phenolics were observed. CO₂ emission also increased with phenolics and salinity. The composition and diversity of eubacterial community significantly differed with soil depth, but not abundance. While there were no changes in composition and abundance of methanogens among soil layers, the diversity was highest at the surface soil. Warming caused a shift in eubacterial community at surface and middle layers, while methanogens did not change at all soil layers. Warming led to decline in bacterial and methanogen diversity at middle and surface layers, respectively. The abundance of methanogens and the ratio of methanogens to eubacteria in terms of abundance also decreased with warming at all soil layers. Seasonal variation in composition, diversity, and abundance was observed in the bog peat. In particular, the summer peats supported more diverse and abundant bacterial community. Bacterial community inhabiting the summer peats showed more similar composition, based on distance matrices. As for autumn peats, while diversity and richness linearly increased with rising temperature, the abundance linearly decreased. Within temperature ranges imposed, most soil enzyme activities linearly increased with temperature, Richness and diversity was positively correlated with soil enzyme activities. Those relationships were more distinct in the summer and autumn peats. The bog, fen and riparian wetland examined supported eubacterial communities with differing abundance, composition, and diversity. Drought was responsible for the decline in abundance of all microbial communities in the bog and fen except for methanogens in the fen. However, the abundance of all microbial communities inhabiting the riparian wetland did not change following drought. Development of a distinct eubacterial community was observed in the riparian wetland following drought, but the other communities were not affected. The eubacterial diversity among the 3 wetlands showed differing responses to drought.;대기 중 이산화탄소 농도와 기온 및 가뭄 횟수가 지속적으로 증가하고 있다. 이러한 기후변화는 전지구적 생지화학순환에 있어 중요한 역할을 감당하는 습지 생태계의 기능에 영향을 미칠 것으로 예상된다. 이 논문의 목적은 미래의 기후변화가 습지 생태계에 미칠 영향을 밝히는데 있다. 연구 결과에 따르면, 대기 중 고농도의 이산화탄소는 습지 식물의 생체량에는 영향을 주지 않는 반면, 토양 내 용존 유기탄소 및 피놀릭의 양을 증가시켰다. 이러한 반응은 토양 내 질소 농도에 의해 조절되었다. 피놀릭 양의 증가는 토양효소 활성도의 감소를 초래하였다. 염습지의 경우 토양 내 염도에 따라 대기 중 이산화탄소에 대한 습지 식물의 반응이 상이하게 나타났다. 고염도의 조건에서 자란 염습지 식물의 경우, 고농도의 이산화탄소에 의해 생체량이 유의적으로 증가한 반면, 대조구에서는 용존 유기탄소와 피놀릭의 양이 증가하였다. 다양한 미생물 군집이 염습지에서 검출되었으며, 특히 황산염 환원세균의 양과 군집구조가 대기 중 이산화탄소 농도와 토양 염도에 의해 변화하였다. 황산염 환원세균의 양은 피놀릭의 양과 염도와 양의 상관관계를 나타내었다. 본 연구는 습지 미생물 군집의 구조와 다양도가 토양 깊이, 계절, 습지 종류, 기후 조건에 따라 유의적으로 상이함을 밝혔다. 이탄 습지에서 토양 깊이에 따른 미생물 군집구조를 분석한 결과, 박테리아의 경우 군집 구조와 다양도가 토양 깊이에 따라 상이한 반면, 메탄 생성 세균은 비슷하였다. 대기 중 온도 증가는 표면층과 중간층에 서식하는 박테리아 군집의 구조변화를 초래하였으며, 박테리아의 양이 메탄 생성 세균에 비해 증가하였다. 이탄 습지는 계절에 따라 구조와 다양도가 유의적으로 다른 박테리아 군집을 보유하였다. 특히 여름철 이탄 습지는 봄과 가을 이탄 습지에 비해 더 다양하고 많은 박테리아 군집을 보유하였다. 이탄의 온도를 점차적으로 증가시킨 결과, 박테리아 군집의 양과 다양도가 증가하였다. 그러나 가을철 이탄 습지에 존재하는 박테리아의 양은 감소하였다. 박테리아 군집의 구조와 다양도는 습지 종류 (보그, 팬, 강하변 습지)에 따라 상이하였다. 가뭄 처리는 보그와 팬에 서식하는 박테리아 군집의 양을 감소시킨 반면, 강하변 습지에 서식하는 박테리아의 양에는 영향을 주지 않았다. 대신 가뭄 처리는 강하변 서식 박테리아의 군집 구조를 변화시켰다. 본 연구는 미래의 기후 변화가 습지 생태계의 식물과 미생물 군집의 변화를 초래할 수 있으며, 이러한 변화는 습지 생태계의 생지화학적 기능에 변화를 초래할 수 있음을 밝혔다.	-
dc.description.tableofcontents	Chapter 1. Introduction = 1 1.1. Global Climate Changes = 1 1.1.1. Global atmospheric concentrations of carbon dioxide = 1 1.1.2. Global warming = 2 1.1.3. Drought = 3 1.2. Objectives of the thesis = 5 Chapter 2. Literature Review = 10 2.1. Effects of elevated atmospheric CO₂ on wetlands = 10 2.1.1. Plants = 10 2.1.2. Soil microorganisms = 24 2.2. The effects of climate changes on wetland microbial community and functioning = 36 2.2.1. Elevated CO₂ concentrations = 36 2.2.2. Drought = 39 2.2.3. Warming = 41 2.3. Ecological perspective on microbial community = 43 2.3.1. Microbial diversity = 44 2.3.2. Relationships between diversity and function = 47 2.3.3. Functional microbial communities = 50 2.4. Wetland ecosystem = 55 2.4.1. Peats and peatlands = 55 2.4.2. Salt marshes and halophytes = 61 2.4.3. Freshwater marshes and vegetation = 64 Chapter 3. Effects of Elevated CO₂ and N Availability on Vegetation and Microbes = 68 3.1. Introduction = 68 3.2. Materials and methods = 72 3.2.1. Model ecosystem = 72 3.2.2. Plant growth and physiochemical measurements = 73 3.2.3. Biochemical analysis = 74 3.2.4. Statistical analysis = 74 3.3. Results = 76 3.3.1. Effects of elevated CO₂ = 76 3.3.1.1. Individual responses of plants to elevated CO₂ = 76 3.3.1.2. Soil enzyme activities = 76 3.3.1.3. Soil respiration = 78 3.3.2. Effects of elevated CO₂and N availability = 83 3.3.2.1. Vegetation = 83 3.3.2.2. DOC = 83 3.3.2.3. Phenolics = 85 3.4. Discussion = 88 3.4.1. DOC = 88 3.4.2. Soil enzyme activities and heterotrophic respiration = 89 3.4.3. Implication of phenolics = 90 3.4.4. N availability = 91 3.4.5. Conclusions = 93 Chapter 4. Effects of Elevated CO₂ and Salinity on Halophytes and Microbial Communities in a Salt Marsh = 94 4.1. Introduction = 94 4.2. Materials and methods = 98 4.2.1. Sampling site = 98 4.2.2. Experimental design = 98 4.2.3. Plant growth and physiochemical measurements = 100 4.2.4. Molecular analyses = 101 4.2.4.1. DNA extraction = 101 4.2.4.2. T-RFLP analysis = 102 4.2.4.3. Analysis of T-RFLP fingerprint patterns = 103 4.2.4.4. Real-time PCR = 103 4.2.5. Statistical analysis = 104 4.3. Results = 106 4.3.1. The responses of halophytes to elevated CO₂ under different salinity regimes = 106 4.3.1.1. Growth measurements = 106 4.3.1.2. Interstitial DOC and phenolics = 107 4.3.1.3. Soil DOC, phenolics, and enzyme activities = 110 4.3.1.4. Soil gas emissions = 111 4.3.2. Comparative microbial community analysis = 114 4.3.2.1. Quantification of microbial communities in a salt marsh = 114 4.3.2.2. The structures of eubacterial, SRB and denitrifiers communities = 117 4.3.2.3. Relationships among measurements = 120 4.4. Discussion = 125 4.4.1. The responses of halophytes to elevated CO₂ = 125 4.4.2. The quantification of microbial communities in the salt marsh = 128 4.4.3. Effects of elevated CO₂ and/or salinity on microbial communities = 129 4.4.4. Relationships between microbial community and gas emissions = 132 4.4.5. Conclusions = 133 Chapter 5. Effects of Warming on Bacterial and Methanogen Communities in a Peat Mire = 136 5.1. Introduction = 136 5.2. Materials and methods = 139 5.2.1. Experimental design = 139 5.2.2. Molecualr analyses = 139 5.2.2.1. DNA extraction and PCR amplification = 139 5.2.2.2. T-RFLP analysis = 142 5.2.2.3. Analysis of T-RFLP fingerprint patterns = 142 5.2.2.4. Real-time PCR = 143 5.2.3. Statistical analysis = 143 5.3. Results = 145 5.3.1. The composition of microbial communities with depth and warming = 145 5.3.2. The diversity of microbial communities with depth and warming = 150 5.3.3. The abundance of microbial communities with depth and warming = 155 5.4. Discussion = 157 5.4.1. Eubacterial community along a soil depth profile and warming effects = 157 5.4.2. Warming effects on eubacterial communities = 159 5.4.3. Warming effects on methanogen community = 160 5.4.4. Conclusions = 162 Chapter 6. Effects of Warming on Bacterial Community and Soil Enzyme Activities = 163 6.1. Introduction = 163 6.2. Materials and methods = 166 6.2.1. Experimental design = 166 6.2.2. Soil enzyme activity assays = 168 6.2.3 .Molecualr analyses = 168 6.2.3.1. DNA extraction and PCR amplification = 168 6.2.3.2. T-RFLP analysis = 169 6.2.3.3. Analysis of T-RFLP fingerprint patterns = 169 6.2.3.4. Real-time PCR = 170 6.2.4. Statistical analysis = 171 6.3. Results = 172 6.3.1. Seasonal differences in bacterial communities = 172 6.3.2. Thermal responses of bacterial community = 172 6.3.3. Thermal response of soil enzyme activities = 178 6.3.4. Relationships between microbial functions and structures = 182 6.4. Discussion = 185 6.4.1. Seasonal differences in bacterial community and soil enzyme activity = 185 6.4.2. Thermal responses of diversity, richness and abundance = 186 6.4.3. The thermal responses of enzyme activities = 187 6.4.4. The linkage between bacterial community and enzyme activities = 188 6.4.5. Conclusions = 189 Chapter 7. Effects of Droughts on Microbial Communities in Bog, Fen, and Riparian Wetlands = 190 7.1. Introduction = 190 7.2. Materials and methods = 194 7.2.1. Manipulations = 194 7.2.2. Molecular anayses = 194 7.2.2.1. DNA extraction and PCR amplification = 194 7.2.2.2. T-RFLP analysis = 195 7.2.2.3. Analysis of T-RFLP fingerprint patterns = 195 7.2.2.4. Real-time PCR = 196 7.2.3. Statistical analysis = 197 7.3. Results = 198 7.3.1. Comparative analysis of microbial communities in three wetland types = 198 7.3.2. The abundance and structures of microbial communities following drought = 203 7.4. Discussion = 207 7.4.1. Comparative analysis of microbial communities in three wetland types = 207 7.4.2. The abundance and structures of microbial communities following drought = 210 7.4.3. Implication of diversity to microbial functions = 212 Chapter 8. Conclusions and Recommendation = 215 8.1. Summary and conclusions = 215 8.1.1. Effects of elevated CO₂ on vegetation and microbes = 215 8.1.2. The responses of halophytes to elevated CO₂ under different salinity regimes = 215 8.1.3. Comparative microbial community analysis and implication of phenolics in a salt marsh under elevated CO₂ and different salinity regimes = 216 8.1.4. The vertical distribution and warming-induced alteration in bacterial and methanogen communities in a peat mire = 216 8.1.5. The seasonal responses of bacterial community and soil enzyme activities to temperature gradients in a bog peat = 217 8.1.6. Microbial community structures and their responses to drought in bog, fen, and riparian wetlands = 218 8.2. Further study = 220 REFERENCES = 223 초록 = 282	-
dc.format	application/pdf	-
dc.format.extent	2630488 bytes	-
dc.language	eng	-
dc.publisher	이화여자대학교 대학원	-
dc.subject.ddc	628	-
dc.title	A study of Wetland Vegetation and Microbial Communities under Elevated CO₂, Warming, and Drought	-
dc.type	Doctoral Thesis	-
dc.creator.othername	Kim, Seon Young	-
dc.format.page	xxiv, 283 p.	-
dc.identifier.thesisdegree	Doctor	-
dc.identifier.major	대학원 환경공학과	-
dc.date.awarded	2007. 8	-