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引用本文:朱云,陈光杰,孔令阳,李静,陈小林,李平,马欠,周起,黄林培,任雁.青藏高原东南缘高山湖泊藻类响应气候变化和大气沉降的长期特征.湖泊科学,2023,35(6):2155-2169. DOI:10.18307/2023.0651
Zhu Yun,Chen Guangjie,Kong Lingyang,Li Jing,Chen Xiaolin,Li Ping,Ma Qian,Zhou Qi,Huang Lingpei,Ren Yan.Long-term patterns of algal changes in response to climate change and atmospheric deposition in alpine lakes along the southeastern margin of Tibetan Plateau. J. Lake Sci.2023,35(6):2155-2169. DOI:10.18307/2023.0651
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青藏高原东南缘高山湖泊藻类响应气候变化和大气沉降的长期特征
朱云, 陈光杰, 孔令阳, 李静, 陈小林, 李平, 马欠, 周起, 黄林培, 任雁
云南师范大学地理学部, 云南省高原地理过程与环境变化重点实验室, 昆明 650500
摘要:
高山湖泊远离人类活动直接影响,通常具有面积小、寡营养、食物网单一等特点,对气候变化和营养输入具有较高的敏感性。我国青藏高原东南缘地区氮沉降通量较高、增温幅度显著,已有研究显示该地区可能受湖泊类型、流域特征等影响存在差异性的湖泊响应模式。本研究选择该区域位于树线以下、具有不同水深的3个小型湖泊(盖公错纳、沃迪错、碧沽天池)开展沉积物调查和对比研究,通过钻孔样品测年、理化特征和藻类(硅藻群落、藻类色素)等多指标分析,结合区域气候定量重建和氮沉降等数据收集,评价了过去300年来藻类演替模式的异同特征及湖泊水深的调节作用。结果显示,3个湖泊中硅藻的优势物种与群落组成差异明显。深水型湖泊盖公错纳(最大水深39.4 m)的硅藻群落以浮游种为主(占比达82%),优势种为眼斑小环藻(Pantocsekiella ocellata)、科曼小环藻(Pantocsekiella comensis);深水型湖泊沃迪错(最大水深20.7 m)的硅藻群落中浮游种和底栖种约各占50%,优势种为眼斑小环藻(Pantocsekiella ocellata)、连结脆杆藻(Staurosira construens);浅水湖泊碧沽天池(最大水深1.7 m)的硅藻群落以底栖种为主(约99%),优势种为极细微曲壳藻(Achnanthidium minutissimum)、小头桥弯藻(Encyonopsis microcephala)。近300年来,2个深水型湖泊(盖公错纳和沃迪错)中硅藻群落变化没有显著的阶段性特征,但初级生产力呈持续上升的趋势;而浅水湖泊(碧沽天池)的硅藻群落出现了明显转变,自1968年开始极细微曲壳藻相对丰度上升且成为优势种,而其沉积物色素浓度呈总体下降趋势。进一步分析发现,驱动3个湖泊硅藻群落变化的环境因子存在差异,盖公错纳主要受到水文波动影响、沃迪错和碧沽天池主要与总氮(TN)有关;与深水湖泊相比,TN对浅水湖泊硅藻群落的驱动作用有所增强。湖泊初级生产力的驱动因子上,盖公错纳中水文和气温变化的影响明显,沃迪错主要受到TN和气温控制,而碧沽天池中水文波动和TN的影响显著。由此可见,位于树线下的高山湖泊藻类演替特征与水深等湖泊类型显著相关,出现了区域增温、大气沉降等相同背景下藻类响应模式的湖泊差异。
关键词:  青藏高原  高山湖泊  气候变化  大气沉降  沉积物  藻类色素  硅藻
DOI:10.18307/2023.0651
分类号:
基金项目:国家自然科学基金项目(42171072)、云南省重点研发计划(202203AC100002-02)、云南省John P. Smol 院士工作站(202005AF150005)和异龙湖高原浅水湖泊云南省野外科学观测研究站(202305AM070002)联合资助。
Long-term patterns of algal changes in response to climate change and atmospheric deposition in alpine lakes along the southeastern margin of Tibetan Plateau
Zhu Yun, Chen Guangjie, Kong Lingyang, Li Jing, Chen Xiaolin, Li Ping, Ma Qian, Zhou Qi, Huang Lingpei, Ren Yan
Yunnan Key Laboratory of Plateau Geographical Processes and Environmental Change, Faculty of Geography, Yunnan Normal University, Kunming 650500, P.R. China
Abstract:
Alpine lakes are often located remotely without the direct impacts of human activities, and usually characterized by small size, low nutrient level, and simple trophic structure, and thus being highly sensitive to climate change and nutrient inputs. Along the southeastern margin of Qinghai-Tibet Plateau, there exists a high flux in nitrogen deposition and a significant increase in temperature. Previous studies had shown that there might exist regional heterogeneity in lake responses in this area that can be linked with lake types and landscape features. In this study, three small-sized lakes (Gaigong Cuona, Wodi Co and Bigu Tianchi) with different water depths, all of which are slightly alkaline and located below the tree line, were selected for sediment surveys and comparative analyses. Multi-proxy analyses, including sample dating, physio-chemical and algal indicators (e.g., diatom assemblage and algal pigments), were carried out in combination with data collation on quantitative reconstruction of regional climate and nitrogen deposition, aiming to evaluate the degree of concordance in algal changes over the last three centuries and the mediating effect of lake depth among lakes. The results showed that there were significant differences in the dominant diatom species and composition of diatom community across lakes. The diatom community was dominated by plankton species (~ 82%) in Gaigong Cuona (maximum depth=39.4 m), including Pantocsekiella ocellata and P. comensis. In Wodi Co (maximum depth=20.7 m), planktonic and benthic taxa accounted for about 50% of the community, respectively, and the dominant species were Pantocsekiella ocellata and Staurosira construens. In contrast, benthic diatoms (~ 99%) was highly dominant in the shallowest lake of Bigu Tianchi (maximum depth=1.7 m), including Achnanthidium minutissimum and Encyonopsis microcephala. In both deep-water lakes (Gaigong Cuona and Wodi Co), the diatom composition showed no significant shift but the primary production (i.e., pigments) displayed a continous increase over the past 300 years. Meanwhile, the diatom community in the shallow lake (Bigu Tianchi) showed obvious changes while the pigment concentration showed a general trend of declining. Specifically, the relative abundance of Achnanthidium minutissimum increased and became the dominant species since ~1968. It was further shown that environmental factors may differ strongly in driving diatom assemblages across lakes. The diatom community was mainly affected by hydrological fluctuations in Gaigong Cuona, but was mainly related to total nitrogen (TN) in both Wodi Co and Bigu Tianchi. Along the depth gradient, TN had a stronger effect on diatom community in shallower lakes. Regarding the driving factors of lake primary production, the hydrological and temperature changes were significant in Gaigong Cuona, TN and temperature factors were obvious in Wodi Co, and the hydrological and TN fluctuations were important in Bigu Tianchi. In conclusion, the algae succession in alpine lakes was found to be significantly linked with lake typology such as water depth, and there may exist a higher degree of sensitivity in algal changes in shallow-water lakes in response to regional warming and atmospheric deposition in Southeast Tibet Plateau.
Key words:  Tibetan Plateau  alpine lakes  climate change  atmospheric deposition  sediment  algal pigment  diatoms
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