東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

The molecular composition of soil or...

Feng, Xiaojuan.

Linked to FindBook

Google Book

Amazon

博客來

The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide./
Author:	Feng, Xiaojuan.
Description:	239 p.
Notes:	Source: Dissertation Abstracts International, Volume: 72-07, Section: B, page: .
Contained By:	Dissertation Abstracts International72-07B.
Subject:	Climate Change. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR73181
ISBN:	9780494731819

The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide.
Feng, Xiaojuan.

The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide. - 239 p.

Source: Dissertation Abstracts International, Volume: 72-07, Section: B, page: .

Thesis (Ph.D.)--University of Toronto (Canada), 2009.

Soil organic matter (SOM) contains about twice the amount of carbon in the atmosphere. With global changes, the potential shifts in SOM quantity and quality are a major concern. Due to its heterogeneity, SOM remains largely unknown in terms of its molecular composition and responses to climatic events. Traditional bulk soil analysis cannot depict the structural changes in SOM. This thesis applies two complementary molecular-level methods, i.e., SOM biomarker gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance (NMR) spectroscopy, to examine the origin and degradation of various SOM components in grassland and temperate forest soils, and to investigate the shifts in microbial community and SOM composition with both laboratory- and field-simulated global changes, such as increasing soil temperatures, frequent freeze-thaw cycles, elevated atmospheric CO2 levels, and nitrogen (N) deposition.

ISBN: 9780494731819Subjects--Topical Terms:

894284
Climate Change.

The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide.
LDR:03392nam 2200265 4500 001 1398988
005 20110915090329.5
008 130515s2009 ||||||||||||||||| ||eng d
020 $a 9780494731819
035 $a (UMI)AAINR73181
035 $a AAINR73181
040 $a UMI $c UMI
100 1 $a Feng, Xiaojuan. $3 1677915
245 1 4 $a The molecular composition of soil organic matter (SOM) and potential responses to global warming and elevated carbon dioxide.
300 $a 239 p.
500 $a Source: Dissertation Abstracts International, Volume: 72-07, Section: B, page: .
502 $a Thesis (Ph.D.)--University of Toronto (Canada), 2009.
520 $a Soil organic matter (SOM) contains about twice the amount of carbon in the atmosphere. With global changes, the potential shifts in SOM quantity and quality are a major concern. Due to its heterogeneity, SOM remains largely unknown in terms of its molecular composition and responses to climatic events. Traditional bulk soil analysis cannot depict the structural changes in SOM. This thesis applies two complementary molecular-level methods, i.e., SOM biomarker gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance (NMR) spectroscopy, to examine the origin and degradation of various SOM components in grassland and temperate forest soils, and to investigate the shifts in microbial community and SOM composition with both laboratory- and field-simulated global changes, such as increasing soil temperatures, frequent freeze-thaw cycles, elevated atmospheric CO2 levels, and nitrogen (N) deposition.
520 $a This thesis has several major findings. First, as the most active component in soil, microbial communities were sensitive to substrate availability changes resulting from prolonged soil incubation, freeze-thaw-induced cell lyses, N fertilization and increased plant inputs under elevated CO2 or soil warming. Microbial community shifts have direct impacts on SOM decomposition patterns. For instance, an increased fungal community was believed to contribute to the enhanced lignin oxidation in an in situ soil warming experiment as the primary degrader of lignin in terrestrial environments. Second, contrast to the conventional belief that aromatic structure was recalcitrant and stable in SOM, ester-bond aliphatic lipids primarily originating from plant cutin and suberin were preferentially preserved in the Canadian Prairie grassland soil profiles as compared with lignin-derived phenols. Cutin- and suberin-derived compounds also demonstrated higher stability during soil incubation. With an increased litter production under elevated CO2 or global warming, an enrichment of alkyl structures that had strong contributions from leaf cuticles was observed in the Duke Forest Free Air CO2 Enrichment (FACE) and soil warming experiments, suggesting an accumulation of plant-derived recalcitrant carbon in the soil. These results have significant implications for carbon sequestration and terrestrial biogeochemistry. Overall, this thesis represents the first of its kind to employ comprehensive molecular-level techniques in the investigation of SOM structural alterations under global changes.
590 $a School code: 0779.
650 4 $a Climate Change. $3 894284
650 4 $a Biogeochemistry. $3 545717
690 $a 0404
690 $a 0425
710 2 $a University of Toronto (Canada). $3 1017674
773 0 $t Dissertation Abstracts International $g 72-07B.
790 $a 0779
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR73181