Dali Lake Research Articles

Carbon and nitrogen signatures of sedimentary organic matter from Dali Lake in Inner Mongolia: Implications for Holocene hydrological and ecological variations in the East Asian summer monsoon margin

Environmental changes in the East Asian summer monsoon (EASM) margin have an important impact on the global climate system. This study presents the results of high-resolution analyses of TOC/TN (C/N) ratio, δ13C and δ15N of sedimentary organic matter extracted from a sediment core from Dali Lake, Inner Mongolia, in order to monitor Holocene hydrological and ecological variations in the EASM margin. Concurrent increases in the values of these proxies are generally interpreted to reflect intensified surface runoff and vegetation development in the lake catchment, elevated lake levels and enhanced lake productivity; however, changes in δ13C and δ15N may also result from within-lake processes due to changes in lake level. These data indicate that Dali Lake experienced gradual rises in water level and primary productivity from 11,500 to 9800 cal yr BP, as documented by increases in TOC and TN concentrations, C/N ratios and δ13C and δ15N values. From 9800 to 7700 cal yr BP, high, stable TOC and TN concentrations and C/N ratios together with low δ13C and δ15N values suggest a status of high stands and high productivity for the lake and a development of terrestrial vegetation in the catchment. Between 7700 and 5900 cal yr BP, TOC and TN were fluctuating at higher concentrations and C/N maintained high ratios, while δ13C increased in its value and δ15N remained at low values, denoting a further rise in lake level and a notable improvement of aquatic and terrestrial ecosystems. Around 5900 cal yr BP, TOC and TN concentrations, C/N ratios and δ13C values decreased abruptly, while δ15N value increased rapidly, implying dramatic drops in lake level and water temperature and drastic declines of aquatic and terrestrial ecosystems. Subsequently all geochemical proxies increased in their values until 4850 cal yr BP, indicating a gradual hydrological and ecological recovery. From 4850 to 750 cal yr BP, decreasing trends of TOC and TN concentrations and C/N ratios and increasing trends of δ13C and δ15N values denote a general decline in the hydrological and ecological conditions. The last 750 cal yrs witnessed the pattern of hydrological and ecological changes occurring from 5900 to 4850 cal yr BP. We suggest that hydrological and ecological changes in the EASM margin during the Holocene were closely related to the combined effects of regional precipitation and temperature which were ultimately controlled by the Northern Hemisphere summer insolation, the boundary conditions and the physical environment of ocean current.

Analysis of muscular nutritional composition in farmed Leuciscus spp. and their hybrids in a low saline-alkaline pond

PDF HTML阅读 XML下载 导出引用 引用提醒 低盐碱池塘养殖雅罗鱼及其杂交种肌肉营养成分分析 DOI: 作者: 作者单位: 1. 淡水鱼类育种国家地方联合工程实验室, 农业部淡水水产生物技术与遗传育种重点实验室, 中国水产科学研究院 特殊生境鱼类种质特性与抗逆育种重点实验室, 中国水产科学研究院 黑龙江水产研究所, 黑龙江 哈尔滨 150070;2. 上海海洋大学 水产与生命学院, 上海 201306 作者简介: 常玉梅(1978-),女,副研究员,专业方向为鱼类分子生物学.E-mail:changyumei@hrfri.ac.cn 通讯作者: 中图分类号: S96 基金项目: 国家自然科学基金项目（31461163004）；黑龙江省科技攻关项目（GCI2B307）. Analysis of muscular nutritional composition in farmed Leuciscus spp. and their hybrids in a low saline-alkaline pond Author: Affiliation: 1. National & Local United Engineering Laboratory of Freshwater Fish Breeding;Key Laboratory of Freshwater Aquatic Biotechnology and Genetic Breeding, Ministry of Agriculture;Key Laboratory of Fish Stress Resistance Breeding and Germplasm Characteristics in Special Habitats, Chinese Academy of Fishery Sciences;Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China;2. College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:本研究旨在为池养雅罗鱼肌肉营养成分的评定和规模化配合饲料的配制提供基础数据。选取达里湖瓦氏雅罗鱼（L. idus，简称GT）以及种内杂交种（达里湖瓦氏雅罗鱼♀×松花江瓦氏雅罗鱼♂，简称DS）和种间杂交种（达里湖瓦氏雅罗鱼♀×高体雅罗鱼♂，简称DG）各15尾，每种鱼等量分成3组，测定其背部肌肉的一般营养成分、氨基酸和脂肪酸含量。结果显示：1）除水分含量无明显差异外，5种养殖雅罗鱼的灰分、粗蛋白和粗脂肪的含量均出现明显差异（<0.05）。其中DS杂交的灰分（1.77%）含量显著高于其他4种雅罗鱼（1.16%~1.22%），粗脂肪含量（7.23%）显著高于其双亲组合（DL 4.31%，SHJ 4.22%）及含量最低的DG杂交（3.32%），表现出超亲的杂种优势；5种养殖雅罗鱼具有较高的蛋白质含量（17.05%~18.80%），其中DG和DL的蛋白质含量明显高于其他3种养殖群体（<0.05），显示出较强的杂种优势；2）5种雅罗鱼肌肉中均测定出18种氨基酸，氨基酸总量（TAA）介于73.058%~79.289%，DG和DL的TAA含量、AAS、CS及EAAI指数均高于其他3种雅罗鱼，与其粗蛋白的测定结果相符，表明母本DL将其高蛋白的遗传特性很好地遗传给了子代，进一步证明了杂种优势；3）5种雅罗鱼肌肉中均检测到23种脂肪酸，饱和脂肪酸（SFA）、单不饱和脂肪酸（MUFA）和多不饱和脂肪酸（PUFA）含量分别为15.03%~19.06%、49.15%~53.92%和27.54%~29.40%，PUFA/SFA比值介于1.53~1.83；SFA和PUFA含量较高的是GT和DL，而MUFA含量较高的是DG和DS两个杂交种。综上所述，5种盐碱池塘养殖雅罗鱼的肌肉营养成分较均衡，属优质蛋白质；杂交选育可以有效改善杂交种的肌肉营养品质，获得的高脂高蛋白的DS杂交和低脂高蛋白的DG杂交可以满足不同的市场需求。 Abstract:This study was conducted to provide basic information for a comprehensive evaluation of nutritional components in the muscle tissues of five cultured fish species and to guide commercial-scale manufacturing of fish feed. Four-year-old originally from Dali Lake (DL) and Songhuajiang River progeny (SHJ), from the Ertix River (GT), and two hybrids, such as hybrids DS (DL♀×SHJ♂) and DG (DL♀×GT♂), were held in a low saline-alkaline pond. Fifteen fish from each genetic group were divided into three replicates, and their nutrient components and muscle amino acid and fatty acid contents were measured and analyzed. The results showed significant differences in ash, crude protein, and crude fat contents among the five genetic groups except that of water (<0.05). Ash content (1.77%) was significantly higher in DS than that in the other four genetic groups (1.16%-1.22%), and crude fat content (7.23%) was significantly higher than that of DL (4.31%), SHJ (4.22%), and the hybrid DG (3.32%). Eighteen amino acids were detected in the five genetic groups, and total amino acid contents were 73.06%-79.29%.The total amino acid components were significantly higher in DG and DL than those in the other three species (<0.05). In addition, the DG and DL groups had higher amino acid, chemical, and essential amino acid index scores than those of the others, which coincided with the higher crude protein content in DL, indicating that the higher crude protein in DG was inherited from DL, and was evidence of hybrid vigor. Twenty-three fatty acids were detected in the five genetic groups, and the saturated fatty acid (SFA), mono-unsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) contents were 15.03%-19.06%, 49.15%-53.92%, and 27.54%-29.40%, respectively. The PUFA to SFA ratio was 1.53-1.83. GT and DL had relatively higher SFA and PUFA contents, and the DG and DS hybrids had higher MUFA contents. Taken together, the five cultured genetic groups had balanced nutrient components in muscle and could be excellent protein sources for human consumption. Nutrient quality was improved effectively through hybridization; thus, satisfying market requirements with higher lipid and protein contents from DS and lower lipid but higher protein contents from DG. 参考文献 相似文献 引证文献

Droughts in the East Asian summer monsoon margin during the last 6 kyrs: Link to the North Atlantic cooling events

Abstract Teleconnections to the high latitudes, forcing by the tropical oceans and solar variability have all been suggested as dominant factors in the sub-millennial global climate changes, yet there is little consensus as to the relative importance of these factors for the East Asian summer monsoon (EASM) variability. This study presents the results of high-resolution analyses of Ca and Mg concentrations, Mg/Ca ratio, δ 18 O and δ 13 C values of endogenic calcites from a sediment core from Dali Lake in the EASM margin, in order to investigate the sub-millennial EASM variability and its possible driving forces during the last 6 kyrs. Increases in these chemical proxy data were interpreted as drought events in the region due to the intensive evaporation losses overwhelming the water input to the lake. The chemical proxy data in this study combined with multi-proxy indicators including grain size component and total organic carbon concentrations from the same sediment core imply that declines in the EASM intensity may have played a dominant role in triggering the drought events during the last 6 kyrs. The results indicate that the EASM intensity significantly declined at the intervals of 5.8–4.75, 3.2–2.8, 1.65–1.15 and 0.65–0.2 kyrs BP. Large declines in the EASM intensity during the last 6 kyrs correspond in time to occurrences of ice-rafted debris in the North Atlantic, indicating that millennial-to-centennial scale changes in the EASM intensity were mainly controlled by climatic processes occurring in the northern high latitudes. These data imply that persistent global warming may be favorable for the strengthening of the EASM circulation and for the transportation of more rainfall to the semi-arid regions of northern China on sub-millennial scales.

Comparison of grain-size distributions between nearshore sections and a deep-water sediment core from Dali Lake, North China, and inferred Holocene lake-level changes

The grain-size distribution of the sediments of closed lake basins is sensitive to lake-level changes and thus to changes in regional climate. Deep-water areas of lakes potentially yield high resolution, continuous records of sedimentation and lake-level changes. In contrast, the marginal areas of lake basins accumulate sediment in a wave-dominated, high-energy environment and may be more sensitive to lake-level changes than deep-water environments, but they might also be more affected by sedimentary hiatuses. Here, we present grain-size data from two sections of exposed nearshore sediments of Dali Lake, North China, and compare them with previously published results from a sediment core from the lake center. We used the grain size-standard deviation method to distinguish various grains-size components of the nearshore sediments, and compared the results with those from surface sediments from various depths in order to investigate past lake-level changes. Combining the grain-size results with a radiocarbon chronology, we defined four lake-level stages during the Holocene: (1) An intermediate lake level from early Holocene to 10.0 cal ka BP. (2) A high lake level from 10.0 to 6.6 cal ka BP. (3) A decline to an intermediate lake level from 6.6 to 1.0 cal ka BP. (4) An abrupt fall to a low lake level from 1.0 cal ka BP to the present when the marginal section was covered with eolian sand. Our results indicate that the total amplitude of lake-level variation during the Holocene was greater than 45 m. This record of lake-level change is in good agreement with previous results obtained from the lake center, and it indicates that the grain-size standard deviation method may be well suited for lake-level reconstruction from nearshore sediments. Moreover, the marginal sections provide evidence of an abrupt short-lived lake-level decline more clearly than the deep-water core.

High-resolution enviromagnetic records of the last deglaciation from Dali Lake, Inner Mongolia

Detailed paleoclimate records during the last deglaciation are highly valuable for understanding rapid climatic changes and mechanisms during extremely variable conditions. High-resolution paleoclimate research in the semi-arid East Asian interior is essential due to its sensitivity to climate variability and importance for human inhabitance. A high-resolution environmental magnetic investigation has been performed on a sedimentary sequence from Dali Lake in central Inner Mongolia, which covers the period of 15.90–11.46ka. Variable magnetic mineral sources are identified based on integrated rock magnetic analysis of both core sediments and catchment samples, complemented by scanning electron telescope and transmission electron telescope observation and X-ray diffraction analysis. The studied core is magnetically divided into four units: Magnetic minerals in Unit 1 (11.83–11.5m, 15.90–15.32ka) are mainly sourced from bedrock erosion of basalts in the catchment. This period corresponds to rapid climate fluctuations after the Last Glacial Maximum. In Unit 2 (11.50–9.50m, 15.32–12.67ka) and Unit 3 (9.50–8.59m, 12.67–11.56ka), pseudo-single domain magnetites from erosion of surface soils are the main magnetic carriers. These two units coincide within time error with the Bølling–Allerød warm period and the Younger Dryas cold period, respectively, and can be correlated with stalagmite and ice core records. Our findings reflect contrasting erosion processes during cold and warm periods in the lake catchment, which were ultimately controlled by climate changes during the last deglaciation.

Characteristics and indications of hydrogen and oxygen isotopes distribution in lake ice body.

Stable isotopes have been used to identify the characteristics of precipitation, evaporation, basin hydrology, and residence times. However, lakes in the cold regions are usually covered by ice for 5-6 months. To get a better understanding of stable isotopes characteristics and indications in lake ice bodies, ice and water were sampled during the icebound season in both the ice and water bodies in Dali Lake, and deuterium, oxygen-18 total nitrogen (TN), and the major ions were analyzed. The results showed that deuterium and oxygen-18 compositions (δD-δ¹⁸O) compositions in the ice body were greater than in the water body beneath, scattered on a straight line, and deviating downward from the global meteoric water line in the top right. The ice profile showed that the δD-δ¹⁸O compositions increased from the ice surface downward and decreased near to the bottom. In contrast, the TN and the major ions in the ice decreased from the ice surface downward and increased near to the bottom, meaning that the concentrations of δ¹⁸O had a negative correlation with the concentrations of TN and major ions. These indicated that stable isotopes can be used for tracing the nutriment and ion transport processes in the ice body.

Insolation driven biomagnetic response to the Holocene Warm Period in semi-arid East Asia.

The Holocene Warm Period (HWP) provides valuable insights into the climate system and biotic responses to environmental variability and thus serves as an excellent analogue for future global climate changes. Here we document, for the first time, that warm and wet HWP conditions were highly favourable for magnetofossil proliferation in the semi-arid Asian interior. The pronounced increase of magnetofossil concentrations at ~9.8 ka and decrease at ~5.9 ka in Dali Lake coincided respectively with the onset and termination of the HWP, and are respectively linked to increased nutrient supply due to postglacial warming and poor nutrition due to drying at ~6 ka in the Asian interior. The two-stage transition at ~7.7 ka correlates well with increased organic carbon in middle HWP and suggests that improved climate conditions, leading to high quality nutrient influx, fostered magnetofossil proliferation. Our findings represent an excellent lake record in which magnetofossil abundance is, through nutrient availability, controlled by insolation driven climate changes.

Testing the model for linking grain-size component to lake level status of modern clastic lakes

A model was proposed recently for linking grain-size component to lake level status based on investigations of Daihai Lake in Inner Mongolia. To test this model, grain-size components of the surface sediments of Dali Lake, 500 km northeast of Daihai Lake, were partitioned and their relationships with the lake level status were examined in this study. The data show that modern clastic sediments of Dali Lake contain five distinct grain-size components representing specific depositional processes and sedimentary environments within the lake in common with Daihai Lake. These components are specified as long-term suspension clay, offshore-suspension fine silt, offshore-suspension medium-to-coarse silt, nearshore-suspension fine sand and nearshore-saltation medium sand. In Dali Lake, by contrast, the offshore-suspension components are lacking in more samples from the nearshore zone; the nearshore-suspension and saltation components occur in more samples from the offshore and transitional zone, respectively; and two adjacent components are well separated. These differences would result from higher-energy hydraulics of Dali Lake generated by stronger and more frequent winds occurring in the lake region. Under this hydraulic condition, clastic materials entering the lake and the resultant components would be reworked more seriously during transportation within the lake, leading to further basin-ward transportations of the major components and better separations of two adjacent components. Percentage of the nearshore components is negatively related to water depth, suggesting the grain-size component–lake level status model for the lake. This model was applied to a sediment core from the lake, showing that high percentages of the nearshore components in the core coincide with low precipitations reconstructed on the pollen profile of the same core. The coincidence of two independent proxies demonstrates the wide applicability of the grain-size component–lake level status model to lake's paleohydrological reconstruction.

达里诺尔湖沉积物中无机碳的形态组成

Sediments play an important role in carbon cycle as the important sources and sinks of carbon.The role of sediments in the carbon cycle is closely related to the forms and distribution of inorganic carbon in the sediments.The forms of inorganic carbon have different capacity in the carbon cycle and recycle.Forms and changes of inorganic carbon in the sediments were essential for the fluxes and processes of carbon across the water-sediment interface.The study of inorganic carbon forms is the basis and premise for discussing their contribution to carbon cycling.In this wok,the sequential extraction method was employed to extract inorganic carbon forms in sediments from Dali Lake.The form distribution characters of inorganic carbon in surface sediments and sediment cores were studied.The correlations between inorganic carbon and physical-chemistry characteristics such as total organic carbon(TOC),total nitrogen(TN),total phosphorus(TP) and biogenic silicate(BSi) were discussed in sediment cores.The results showed that the dominant form of inorganic carbon was NH2OH·HCl form both in surface sediment and sediment cores;The content of NH2OH·HCl form in sediments ranges from 6.26 to 17.51 mg/g,with mean content of 14.02 mg/g,accounted for 82.77% of the total inorganic carbon in the sediments.The contents of inorganic carbon forms in surface sediment are rank as: NH2OH·HCl form HCl form NaCl form NH3·H2O form NaOH form.In terms of the horizontal characteristics,the central area was the high value area of inorganic carbon form,the east and north area were the low value area in the lake.Water depth and inorganic carbon present a good positive correlation(R2=0.86,P0.01).The correlationship and the horizontal characteristics of inorganic carbon implied that the terrigenous material which were carried by inflowing rivers have dilute effect on sediments.The supersaturation coefficients of Calcium carbonate in different year in Dali Lake are far greater than 1(31.59IAP/Ksp166.92).The calculation results showed that calcium carbonate was supersaturation in the lake and implied that the aquatic environmental conditions were beneficial to authigenic carbonate precipitation in Dali Lake.In sediment cores,the content of NH2OH·HCl form ranges from 5.29 to 21.72 mg/g,with mean content of 12.90 mg/g,accounted for 82.21% of the total inorganic carbon in the sediments.The contents of NH2OH·HCl form in sediment cores of DLNE-3 and DLNE-5 are obviously higher than DLNE-8 and DLNE-10.The former lied in deep water area are weakly affected by the dilution effect of terrigenous input,which is beneficial to authigenic carbonate precipitation.The latter lied in shallow water area are strongly affected by the dilution effect of terrigenous input,which is not helpful for authigenic carbonate precipitation.The correlations between inorganic carbon and nitrogen,phosphorus,biogenic silicate in the sediments implied that nutrients rising can promote the formation of calcium carbonate supersaturation.In addition,the physical and chemical properties changes in aquatic environment caused by photosynthesis was one of the important factors leading to precipitation of carbonate.

Bacillus daliensis sp. nov., an alkaliphilic, Gram-positive bacterium isolated from a soda lake

A Gram-positive, alkaliphilic bacterium, designated strain DLS13T, was isolated from Dali Lake in Inner Mongolia Autonomous Region, China. The isolate was able to grow at pH 7.5-11.0 (optimum at pH 9), in 0-8 % (w/v) NaCl (optimum at 2 %, w/v) and at 10-45 °C (optimum at 30 °C). Cells of the isolate were facultatively anaerobic, spore-forming rods with peritrichous flagella. The predominant isoprenoid quinone was MK-7 and its cell wall peptidoglycan contained meso-diaminopimelic acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were anteiso-C15:0, anteiso-C17:0 and iso-C15:0. The genomic DNA G+C content of the isolate was 43.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain DLS13T was a member of the genus Bacillus and most closely related to Bacillus saliphilus DSM 15402T (96.9 % similarity). The DNA-DNA relatedness value between strain DLS13T and B. saliphilus DSM 15402T was 38.7±1.9 %. Comparative analysis of genotypic and phenotypic features indicated that strain DLS13T represents a novel species of the genus Bacillus, for which the name Bacillus daliensis sp. nov. is proposed; the type strain is DLS13T (=CGMCC 1.10369T=JCM 17097T=NBRC 107572T).

Similar distribution pattern of different phenotypes of Limnocythere inopinata (Baird) in a brackish-water lake in Inner Mongolia

It has been recognized long ago that Limnocythere inopinata is a widely distributed ostracod and comprises various phenotypes. The taxonomy of the different phenotypes and their ecological differences, however, are still under debate. In this study, we investigated the relationships between ostracod distribution, water depth, and the substrate based on the analyses of species composition, abundance, and age structure of ostracods in 51 surface-sediment samples from Dali Lake in Inner Mongolia in order to reveal the distribution pattern and habitat characteristics of the ostracods. The identification of a total of 32,182 valves indicates that the dominant ostracod in Dali Lake is L. inopinata, which includes unnoded, 1-, 2- and 3-node and 1-carina phenotypes. The distribution of L. inopinata is affected both by the water depth and by the sand content of the substrate, and the phenotypes show their maximum abundances in the intermediate zone of the lake. All the phenotypes of L. inopinata display a similar preference for water depth and substrate, implying that the occurrence of different phenotypes is controlled by other factors. The age structure of L. inopinata is mainly related to the sand content, with the percentage of adults increasing and that of early juveniles decreasing with increasing sand content. Our data suggest that the occurrence of L. inopinata is closely related to water depth and substrate grain size, and different phenotypes of L. inopinata respond in a similar pattern to water depth and substrate.

Partitioning of the grain-size components of Dali Lake core sediments: evidence for lake-level changes during the Holocene

We recovered a sediment core (DL04) from the depocenter of Dali Lake in central-eastern Inner Mongolia. The upper 8.5 m were analyzed at 1-cm intervals for grain-size distribution to partition the grain-size components and provide a high-resolution proxy record of Holocene lake level changes. Partitioning of three to six components, C1, C2, C3 through C6 from fine to coarse modes within the individual polymodal distributions, into overlapping lognormal distributions, was accomplished utilizing the method of lognormal distribution function fitting. Genetic analyses of the grain-size components suggest that two major components, C2 and C3, interpreted as offshore-suspension fine and medium-to-coarse silt, can serve as sediment proxies for past changes in the level of Dali Lake. Lower modal sizes of both C2 and C3 and greater C3 and lower C2 percentages reflect higher lake stands. The proxy data from DL04 core sediments span the last 12,000 years and indicate that Dali Lake experienced five stages during the Holocene. During the interval ca. 11,500–9,800 cal year BP, lake level was unstable, with drastic rises and falls. Following that interval, the lake level was marked by high stands between ca. 9,800 and 7,100 cal year BP. During the period from ca. 7,100 to 3,650 cal year BP, lake level maintained generally low stands, but displayed a slight tendency to rise. Subsequently, the lake level continued rising, but exhibited high-frequency, high-amplitude fluctuations until ca. 1,800 cal years ago. Since ca. 1,800 cal year BP, the lake has displayed a gradual lowering trend with frequent fluctuations.

Hydrology of Dali Lake in central-eastern Inner Mongolia and Holocene East Asian monsoon variability

Lacustrine records from the northern margin of the East Asian monsoon generate a conflicting picture of Holocene monsoonal precipitation change. To seek an integrated view of East Asian monsoon variability during the Holocene, an 8.5-m-long sediment core recovered in the depocenter of Dali Lake in central-eastern Inner Mongolia was analyzed at 1-cm intervals for total organic and inorganic carbon concentrations. The data indicate that Dali Lake reached its highest level during the early Holocene (11,500–7,600 cal yr BP). The middle Holocene (7,600–3,450 cal yr BP) was characterized by dramatic fluctuations in the lake level with three intervals of lower lake stands occurring 6,600–5,850, 5,100–4,850 and 4,450–3,750 cal yr BP, respectively. During the late Holocene (3,450 cal yr BP to present), the lake displayed a general shrinking trend with the lowest levels at three episodes of 3,150–2,650, 1,650–1,150 and 550–200 cal yr BP. We infer that the expansion of the lake during the early Holocene would have resulted from the input of the snow/ice melt, rather than the monsoonal precipitation, in response to the increase in summer solar radiation in the Northern Hemisphere. We also interpret the rise in the lake level since ca. 7,600 cal yr BP as closely related to increased monsoonal precipitation over the lake region resulting from increased temperature and size of the Western Pacific Warm Pool and a westward shifted and strengthened Kuroshio Current in the western Pacific. Moreover, high variability of the East Asian monsoon climate since 7,600 cal yr BP, marked by large fluctuations in the lake level, might have been directly associated with variations in the intensity and frequency of the El Nino-Southern Oscillation (ENSO) events.