【摘要】：通過測(cè)定撫仙湖沉積物全有機(jī)樣品的穩(wěn)定碳同位素組成(δ~(13)C_(org))、總氮、總有機(jī)碳含量指標(biāo)并計(jì)算碳氮比值,對(duì)過去5000 a以來(lái)?yè)嵯珊练e物有機(jī)質(zhì)來(lái)源、δ~(13)C_(org)的影響因素及其所指示的古環(huán)境意義進(jìn)行分析.結(jié)果表明:在過去的5000 cal a BP里,撫仙湖沉積物有機(jī)質(zhì)主要來(lái)源發(fā)生明顯變化,沉積物有機(jī)質(zhì)輸入由內(nèi)源水生生物和陸生C_3植物共同輸入(5000-2300 cal a BP階段)轉(zhuǎn)變?yōu)橐詢?nèi)源沉水植物、浮游植物和藻類等輸入為主(2000 cal a BP至今階段);有機(jī)質(zhì)來(lái)源發(fā)生變化是造成撫仙湖沉積物δ~(13)C_(org)值變化的主要原因;2000 cal a BP以來(lái),陸源有機(jī)質(zhì)輸入的銳減與人類活動(dòng)的影響密切相關(guān);在2300-2000 cal a BP階段,撫仙湖沉積物δ~(13)C_(org)值的快速變化可能指示了撫仙湖流域的古環(huán)境在這一時(shí)期經(jīng)歷了快速變化的氣候事件.
[Abstract]:The source of organic matter in Fuxian Lake sediments since the past 5000 years was studied by measuring the stable carbon isotopic composition (未 ~ (13) C _ (org), total nitrogen and total organic carbon content index and calculating the ratio of carbon to nitrogen) of the total organic samples of Fuxian Lake sediment. The influencing factors of 未 ~ (13) C _ (org) and their paleoenvironmental significance were analyzed. The results show that in the past 5000 cal a BP, the main source of organic matter in Fuxian Lake sediment has changed obviously. The organic matter input of sediment changed from endogenous aquatic organisms and terrestrial C _ 3 plants (5000-2300 cal a BP) to endophyte, phytoplankton and algae (2000 cal a BP to now). The change of organic matter source is the main reason for the change of 未 ~ (13) C _ (org) value in the sediments of Fuxian Lake, and the sharp decrease of terrestrial organic matter input is closely related to the influence of human activities since 2000 cal a BP. During the period of 2300-2000 cal a BP, the rapid change of 未 ~ (13) C _ (org) in the sediment of Fuxian Lake may indicate that the paleoenvironment of Fuxian Lake basin experienced a rapidly changing climatic event in this period.
【作者單位】： 云南師范大學(xué)旅游與地理科學(xué)學(xué)院;云南師范大學(xué)高原湖泊生態(tài)與全球變化重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家自然科學(xué)基金項(xiàng)目(41201203) 云南省高端人才引進(jìn)項(xiàng)目(2010CI111) 湖泊沉積與環(huán)境變化云南省創(chuàng)新團(tuán)隊(duì)項(xiàng)目(2010CI)聯(lián)合資助
【分類號(hào)】：P532;P597

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