廖梦娜^1,,
黄汇豪¹,
毛欣^2,3
1. 浙江师范大学化学与生命科学学院, 浙江 金华 321004
2. 中国地质科学院水文地质环境地质研究所, 河北 石家庄 050061
3. 中国地质调查局第四纪年代学与水文环境演变重点实验室, 河北 石家庄 050061

基金项目: 河北省自然科学基金项目(批准号: D2018504013)、中国地质科学院基本科研业务费专项项目(批准号: SK202007)和中国地质调查项目(批准号: G201801-7)共同资助


详细信息

作者简介: 廖梦娜, 女, 33岁, 讲师, 湖泊沉积与环境演化研究, E-mail: mnliao@zjnu.edu.cn

中图分类号: P941.78;Q949.27⁺1

收稿日期:2020-11-09
修回日期:2021-04-20
刊出日期:2021-09-30

A diatom record for eco-environmental change in Baiyangdian Lake over the recent 80 years

LIAO Mengna^1,,
HUANG Huihao¹,
MAO Xin^2,3
1. College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, Zhejiang
2. Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, Hebei
3. Key Laboratory of Quaternary Chronology and Hydro-Environmental Evolution, China Geological Survey, Shijiazhuang 050061, Hebei


MSC: P941.78;Q949.27⁺1

--> Received Date: 09 November 2020
Revised Date: 20 April 2021
Publish Date: 30 September 2021


摘要
摘要:白洋淀是雄安新区实现"以水定城"理念的关键，了解其生态变化轨迹及特征有望为白洋淀的治理提供科学参考依据。本文基于取自白洋淀东南部湖区的一根长79 cm的沉积岩芯，分析该岩芯的硅藻记录并结合沉积物地球物理和化学指标、气象监测数据及人类活动指标，重建了该湖区近80年的硅藻属种组合及多样性变化过程和特征并探讨其变化机制。研究结果表明，Achnanthidium minutissimum、Amphora copulata、Puncticulata praetermissa、Pantocsekiella ocellata和Cyclotella distinguenda是沉积硅藻群落的优势种。本研究分析的物种多样性指数包括物种丰富度、均匀度和β多样性指数（β_sor）。其中，物种丰富度和均匀度呈总体上升趋势，β_sor呈总体下降趋势，说明过去80年硅藻属种数量净获得量增加，但硅藻群落结构变化趋于均匀化。冗余分析（RDA）和变差分解（VPA）显示气候和人类活动因子对硅藻属种组合和多样性变化产生了不同程度的影响，其中年均温、湖水位和沉积物P元素含量的贡献较大。年均温对硅藻属种组合变化的独立解释百分比最大，说明未来气候持续变暖的条件下，气温对白洋淀生态系统的影响可能会增强。湖水位对硅藻多样性变化的贡献最大，说明维持生态需水量对保护白洋淀生物多样性的重要性。基于普通最小二乘法残差的累积和（OLS-CUSUM）未检测出硅藻属种组合和多样性存在突变点，说明过去几十年人类活动和气候变化尚未造成该湖区生态系统稳态的转化。因此，减轻环境压力有望保持该湖区生态系统的恢复力和稳定性。但对于重污染湖区，其硅藻优势种和属种组合变化与本研究湖区存在很大差异，需进一步研究以获得更具针对性的水环境治理对策。
关键词: 硅藻属种组合/
生物多样性/
湖泊沉积/
白洋淀/
人类活动/
气候变化

Abstract:Baiyangdian Lake (38°44'~38°59'N, 115°45'~116°07'E) is the key to realizing the concept of "Setting the City by Water" for Xiong'an New Area. Understanding the process and characteristics of the eco-environmental change in Baiyangdian Lake will provide scientific data for water and environmental management. This study reconstructed the history of diatom compositional and diversity changes based on a 79-cm long sediment record(CPT) (38.83°N, 116.04°E) extracted from the southeast part of the Baiyangdian Lake at a water depth about 3 m, and discussed the mechanisms behind the changes by combining physical and geochemical proxies from the same core, regional meteorological data and indices reflecting human activities. In this study, a total of 40 samples collected from the core at 2-cm intervals were measured for ²¹⁰Pb and ¹³⁷Cs activities. According to the ²¹⁰Pb/¹³⁷Cs-based age-depth model, the basal sediment at 79-cm depth was deposited around 1938 A.D. The average sedimentary rate throughout the core was estimated ca. 0.984 cm/a. 71 samples from different depths were collected for grain-size analysis and 40 samples were taken at 2-cm intervals for diatom analysis. The results show that the dominate species in the core include Achnanthidium minutissimum, Amphora copulata, Puncticulata praetermissa, Pantocsekiella ocellata and Cyclotella distinguenda. The major diatom compositional shifts occurred around 1955 A.D., 1973 A.D., 1993 A.D. and 2002 A.D. Redundancy analysis(RDA) and variance partitioning analysis(VPA) show that climatic variables and human activities exerted different amounts of influence on diatom compositional and diversity changes, for which annual mean temperature, lake level and P content contributed more compared to other variables. Annual mean temperature has the largest independent explanation for the variations of diatom compositional change, indicating that temperature will probably exert stronger impact on the lake ecosystem if the climate keep warming. Three species diversity indices, including species richness, species evenness and β diversity(β_sor), were calculated for the diatom data from the core. Among these indices, species richness and evenness show overall increasing trends while β_sor reveals a decreasing trend over the past 80 years. This implies a net diatom species gain in the southeast part of the Baiyangdian Lake during this period, but meanwhile, the diatom community structure became homogenized. Ordinary least square cumulative sum(OLS-CUSUM) failed to detect catastrophe point from diatom composition(PC1) and diatom diversity(species richness, species evenness and β_sor), which indicates that human activities and climate change over the recent decades have not yet caused remarkable shift in the lake ecological regime. Therefore, we believed that reducing environmental pressure is expected to maintain the resilience and stability of the aquatic ecosystem in the southeast part of Baiyangdian Lake. For the heavily polluted lake area like the Shaochedian in the north part of the lake, the dominant species in the lake sediments and the trajectory of diatom compositional change are completely different from the present study. Further analyses are required to detect whether ecological regime had shifted or not in such lake area. In view of the great spatial difference of the water environment in Baiyangdian Lake, we suggested that strategies for water environmental protection should be developed according to site-specific conditions.
Key words:diatom composition/
biodiversity/
lake sediment/
Baiyangdian Lake/
human activities/
climate change



PDF全文下载地址:

http://www.dsjyj.com.cn/data/article/export-pdf?id=fa5b45cc-f44a-4a82-a04b-5907ac7a8b9e