【摘要】：湖泊生物及其殼體對(duì)湖泊環(huán)境變化具有響應(yīng)敏感、快速等特征,包含年際或季節(jié)性的氣候變化信息,已成為古環(huán)境學(xué)與古湖泊學(xué)領(lǐng)域的研究熱點(diǎn)之一。生物殼體同位素組成特征作為識(shí)別古環(huán)境、古氣候的有效指標(biāo),已在眾多湖泊研究中的得到了應(yīng)用。選擇同一種生物殼體對(duì)于認(rèn)識(shí)同位素所代表的環(huán)境特征具有重要意義。本文選擇滇中湖泊,如滇池、撫仙湖、星云湖、杞麓湖以及異龍湖,作為研究對(duì)象,通過(guò)對(duì)其湖泊孟氏螺螄殼體及宿生水體的同位素組成測(cè)定,利用多指標(biāo)、多變量分析方法,探討了食物對(duì)生物殼體穩(wěn)定同位素分餾的影響,并分析了現(xiàn)生生物殼體同位素組成與湖泊水質(zhì)參數(shù)之間的關(guān)系,由此討論了孟氏螺螄殼體對(duì)區(qū)域溫度、降水量等氣候環(huán)境指標(biāo)的響應(yīng)機(jī)制。本文得出如下幾點(diǎn)結(jié)論:1湖水氧同位素組成變化一定程度上受降水同位素組成和氣溫的影響;滇中湖泊現(xiàn)生孟氏螺螄殼體δ~(13)C和δ~(18)O的值4月偏正,9月、11月和12月偏負(fù),從生長(zhǎng)層分析可以得出,螺層體螺層殼頂。異龍湖和杞麓湖孟氏螺螄殼體碳穩(wěn)定同位素之間的差異一定程度上受氣候、水環(huán)境、食物等因素的綜合影響。2殼體穩(wěn)定同位素對(duì)其宿生水體的響應(yīng)主要體現(xiàn)在孟氏螺螄殼體碳同位素對(duì)電導(dǎo)率環(huán)境信息的反映,它們之間存在明顯的負(fù)相關(guān)系,而對(duì)水溫、pH水環(huán)境參數(shù)指標(biāo)并沒(méi)有明顯的反映。孟氏螺螄殼體穩(wěn)定氧同位素對(duì)其宿生水體環(huán)境參數(shù)各項(xiàng)指標(biāo)都沒(méi)有發(fā)現(xiàn)良好的反映和錄。3水草對(duì)孟氏螺螄殼體穩(wěn)定同位素的影響主要體現(xiàn)在水草δ~(13)C水草對(duì)孟氏螺螄殼體氧同位素的影響、水草δ~(15)N水草對(duì)孟氏螺螄殼體氧同位素的影響C/N比值對(duì)孟氏螺螄殼體碳氧同位素的影響。水草干濕比值、碳含量和氮含量與孟氏螺螄殼體同位素沒(méi)有明顯的相關(guān)性,表明這些指標(biāo)對(duì)生物殼體沒(méi)有重要影響。4區(qū)域降水量和降水同位素的組成直接影響湖泊水同位素組成與分餾,孟氏螺絲的殼體穩(wěn)定同位素對(duì)水草穩(wěn)定同位素敏感響應(yīng)和高度相關(guān),另一方面,氣溫通過(guò)調(diào)節(jié)湖泊流域內(nèi)的水循環(huán),控制水分的蒸發(fā)平衡以及湖泊水位,氣溫升高時(shí),湖泊水富集重同位素。
[Abstract]:Lacustrine organisms and their shells have the characteristics of sensitive and rapid response to lake environmental change, including interannual or seasonal climate change information, which has become one of the research hotspots in the field of paleoenvironment and paleolacustrine. As an effective index to identify paleoenvironment and paleoclimate, the isotopic composition characteristics of biological shell have been applied in many lake studies. The selection of the same biological shell is of great significance for understanding the environmental characteristics represented by isotopes. In this paper, the central Yunnan lakes, such as Dianchi Lake, Fuxian Lake, Xingyun Lake, Qilu Lake and Yilong Lake, were selected as the research objects. By measuring the isotopic composition of the shell and the persistent water body of the lake, the influence of food on the stable isotopic fractionation of the biological shell was discussed by using the method of multi-index and multivariable analysis, and the relationship between the isotopic composition of the present biological shell and the water quality parameters of the lake was analyzed. The response mechanism of Mencius snail shell to regional temperature, precipitation and other climatic and environmental indexes is discussed. In this paper, the following conclusions are drawn: (1) the change of oxygen isotopic composition in lake water is affected to some extent by precipitation isotopic composition and air temperature, and the values of 未 ~ (13) C and 未 ~ (18) O in the existing Montellodes shell in central Yunnan are positive in April, negative in September, November and December. From the analysis of the growth layer, it can be concluded that the snail shell top of the snail layer can be obtained. To some extent, the difference between carbon stable isotopes of Mongol snail shell in Yilong Lake and Qilu Lake is affected by climate, water environment, food and other factors. 2 the response of shell stable isotopes to the environmental information of conductivity is mainly reflected in the reflection of carbon isotopes in the shell of Mongol snail shell to the environmental information of conductivity, and there is an obvious negative phase relationship between them, but there is no obvious reflection on the water temperature and pH water environment parameters. The stable oxygen isotopes of Mencius mandarin shell were not well reflected and recorded. 3 the effect of water grass on the stable isotopes of Mencius mandarin shell was mainly reflected in the effect of water grass 未 ~ (13) C water grass on oxygen isotopes of Montellostella mongolica shell, and the effect of water grass 未 ~ (15) N water grass on oxygen isotopes of Montellostella mongolica shell. The effect of C 鈮，

本文編號(hào)：2503776