气候变化领域集成服务门户(CCPortal): 云南星云湖现代盘星藻与湖泊水深关系及其化石记录的探讨

CCPortal

	云南星云湖现代盘星藻与湖泊水深关系及其化石记录的探讨
其他题名	A preliminary investigation of relationship between modern Pediastrum and the level of Xingyun Lake, central Yunnan, and its implications for the interpretation of the fossil record
	陈雪梅; 黄小忠; 唐领余; 陈发虎
发表日期	2016
ISSN	0023-074X
卷号	61 期号:21 页码:2395-2408
中文摘要	盘星藻化石在我国第四纪湖相地层中频繁出现, 但其在第四纪古环境研究中的指示意义存在较大的争议. 一些研究认为盘星藻大量的出现代表了湖泊变浅, 一些研究则认为盘星藻主要集中在湖泊水深较大的区域.本文对位于云南中部的星云湖现代水样和湖床表层沉积物样品中盘星藻的分布状态进行调查研究, 结果显示湖面水体中盘星藻浓度在水平方向上随水深基本没有变化, 在垂直方向上盘星藻在湖水底部浓度最大, 推测可能与盘星藻重力沉降及波浪扰动底泥产生的再沉积作用有关; 湖床表层沉积物中盘星藻含量与水深无明显关系. 初步认为, 在一些较大湖泊的沉积物中, 盘星藻的分布与水深的关系可能是沉积过程造成的, 较大湖泊中风浪的作用使得盘星藻趋中沉积非常明显; 而湖水中是否有大量盘星藻生长可能与河流输入、水体营养化状态、水温、pH、盐度等水环境状态有关. 不同区域、不同类型的湖泊可能机制并不一样, 没有统一的规律. 因此, 在第四纪古环境研究中将盘星藻含量作为水深的指标需结合其他指标综合分析. 星云湖过去3000年化石盘星藻含量的变化与沉积物粒度和磁化率指示的区域人类活动强度变化趋势一致, 且更敏感地响应了人类活动导致的湖泊水体富营养化过程.
英文摘要	Fossil Pediastrum is frequently found in Quaternary lacustrine deposits and has attracted much attention because it can be well preserved and easily identified. However its palaeoenvironmental significance is unclear. Several studies suggest that the occurrence of a large amount of Pediastrum indicates a gradually decreasing lake-level, while others point out that Pediastrum mainly occurs in the deep areas of lakes. Thus clarifying the relationship between Pediastrum and lake levels is of great importance for improving the reliability of palaeoenviromental reconstruction. In this study, we investigated the occurrence of Pediastrum in Xingyun Lake, a semi-enclosed shallow fault and eutrophic lake located in central Yunnan Province, southwest China. We obtained 4 lake surface water samples at water depths of 4, 4.5, 5.2 and 6.5 m; 16 water samples collected at various depths within the water column at the deepest part of the lake; and 10 lake surface sediment samples taken at different water depths from the lake shore to the deepest part using a Grab sampler. We present the results of Pediastrum analysis of samples of both the lake water and surface sediments of Xingyun Lake and discuss the relationship between the Pediastrum distribution and the lake-level/water depth. The variation of the fossil records during the past 3000 years is also reported. The results show that two types of Pediastrum were identified in the water and lake sediment samples, including Pediastrum boryanum and Pediastrum simplex. The concentration of Pediastrum in the water samples is extremely low, varying from 2 to 6 grains mL~(-1). Spatially, the concentrations of Pediastrum in the surface lake water samples exhibit little change with increasing water depth. In terms of the depth variation within the water column in the deepest part of the lake, the Pediastrum concentration of the bottom sample is the highest, which may be related to the effects of resuspension and redeposition of lake sediments caused by wind-induced turbulence in shallow water. With respect to the lake surface sediment samples, the Pediastrum content is relatively high. The concentration of Pediastrum varies from 60700 to 104000 grains g~(-1), with an average of 81000 grains g~(-1); and the relative percentage abundance ranges from 66%-80%, averaging around 76%. Interestingly, both the concentration and percentage content of Pediastrum in these samples exhibit no significant relationship with water depth. Based on comparison of the results from Xingyun Lake with those of other workers, we conclude that the relationship between the Pediastrum distribution and water depth inferred from the lake sediments of several relatively larger lakes mentioned in previous studies may be caused by depositional processes: turbulence resulting from wave activity in these larger lakes could result in the resuspension of Pediastrum in shallow water and its focusing into deeper areas. However, whether or not there is a large quantity of Pediastrum living in the lake water may be related to the physicochemical status of the lake water, determined by factors such as the river input, nutrient level, temperature, pH and salinity. In addition, these factors may vary between different lakes in different regions.
关键词	盘星藻水环境指标水位变化营养变化星云湖
英文关键词	Pediastrum;water environment indicator;lake levels;nutritional change;Xingyun Lake
语种	中文
WOS研究方向	Paleontology
WOS类目	PALEONTOLOGY
CSCD记录号	CSCD:5757880
来源期刊	科学通报
来源机构	兰州大学 ; 中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/1577
推荐引用方式 GB/T 7714	陈雪梅,黄小忠,唐领余,等. 云南星云湖现代盘星藻与湖泊水深关系及其化石记录的探讨[J]. 兰州大学, 中国科学院青藏高原研究所,2016,61(21):2395-2408.
APA	陈雪梅,黄小忠,唐领余,&陈发虎.(2016).云南星云湖现代盘星藻与湖泊水深关系及其化石记录的探讨.科学通报,61(21),2395-2408.
MLA	陈雪梅,et al."云南星云湖现代盘星藻与湖泊水深关系及其化石记录的探讨".科学通报 61.21(2016):2395-2408.