2006 Fiscal Year Final Research Report Summary
Elucidation of changes in long-term environments and biological systems in the northeast Asia by the use of lake sediments in the Lake Baikal basin
| Project/Area Number |
16310012
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Otsuma Women's University |
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Principal Investigator |
INOUE Genki (松本 源喜) Otsuma Women's University, School of Social Information Studies, Professor (80245357)
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| Co-Investigator(Kenkyū-buntansha) |
TANI Yukinori University of Shizuoka, Institute for Environmental Sciences, Research Associate (10285190)
HASE Yoshitaka Kumamoto University, Faculty of Science, Professor (40040109)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Lake Baikal basin / Lone-term environmental change / Sediment core / Biomarker / Fossol pollen |
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| Research Abstract |
We studied changes in long-term paleoenvironment for 1.03 million years and biological systems in the northeast Asia by the use of biomarkers including plant pigments, and fossil pollens in sediment cores from Lake Hovsgol in the Lake Baikal basin. Direct pyrolysis and methylation of sediment samples combined with gas chromatography-mass spectrometry (PyMeGCMS) were, in addition, carried out to develop rapid analysis of biomarkers in the sediment cores.
Gravity cores (X106, HV05ST2, HV05ST3) have detailed information on changes in paleoenvironment and biological systems during the last glacial period to the present. AMS dating (conventional age) of the cores showed sediment ages were less than 24,000 years. Biological production in the glacial period based on total organic carbon (TOC) contents was very low, increased to Bolling-Allerod (ca. 12,000 yBP), decreased to Younger Dryas event (ca. 11,000 yBP) and then increased again to the post glacial period. Scarce herbaceous plant vegetat
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ion such as Altemisia spp. on the land and small amount of plankton were distributed under perennial ice cover in the glacial period. Woody plant vegetation increased in the warm post glacial period, along with increase of lake plankton.
Sedimentation ages of HDP04 sediment core (80.0 m) were determined 1.03 million years by paleomagnetism (Brunhes-Matuyama, Jaramillo Chron). Pattern of TOC contents of the core was well not correlated with that of marine isotope stages, reflects largely local climatic changes in the drainage basin rather than global climatic changes. Biological production in Lake Hovsgol was relatively low for the last 1.03 million years except for Holocene, and was somewhat lower than that of Lake Baikal. Contribution of allocthonous organic matter in Lake Hovsgol was much higher than that of Lake Baikal, reflecting probably small drainage basin of Lake Hovsgol. The presence of bacteriochlorophyls specific to brown-Chlorobium in the depths between 19-21 m of the core suggests strongly that lake bottom was anoxic due to the stagnant of the lake water.
A series of fatty acids and phenolcarboxylic acid were detected in HV05ST2 sediment core by PyMeGCMS. The pattern of these compounds were similar to that of those compounds found in ethyl acetate extracts of the core, revealed that PyMeGCMS was useful for the rapid determination of biomarkers in the sediment core. Less
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Research Products
(38 results)
