MODERN CLIMATIC SIGNALS DEDUCED FROM STABLE ISOTOPE IN SHELLS IN XINGCUO LAKE SEDIMENTS,EAST TIBETAN PLATEAU,CHINA

Ｉｔｉｓｏｎｅｏｆｔｈｅｆｒｏｎｔｉｅｒｆｏｃｕｓｅｓｉｎｔｈｅｆｉｅｌｄｏｆｇｌｏｂｌｅｅｎｖｉｒｏｎｍｅｎｔａｌｃｈａｎｇｅｓｔｏｅｘｔｒａｃｔｑｕａｎｔｉｔａｔｉｖｅｌｙｐａｓｔｃｌｉｍａｔｉｃｓｉｇｎａｌｓｆｒｏｍｌａｋｅｓｅｄｉｍｅｎｔｒｅｃｏｒｄｓ．Ｉｎｔｈｅｒｅ-ｃｅｎｔｄｅｃａｄｃｉｏｕｓｙｅａｒｓａｓｅｒｉｅｓｏｆａｃｈｉｅｖｅｍｅｎｔｓｏｎｒｅ-ｂｕｉｌｄｉｎｇｔｈｅｓｅｑｕｅｎｃｅｓｏｆｃｌｉｍａｔｉｃａｎｄｅｎｖｉｒｏｎｍｅｎｔａｌｅｖｏｌｕｔｉｏｎｓａｔｖａｒｉｏｕｓｓ…     

Episodes of volcanic activity and their environmental effects in the Okinawa Trough during the last 150 ka

1 INTRODUCTIONA large-scale volcanic eruption can injectenormous amount of ash and dust into the atmos-phere, leading to local and short cooling due toshielding incoming radiation. During the past 2 to 3decades, accumulated evidence indicated thatlarge-scale volcano eruptions or series of volcanicactivity appears to coincide with climatologicaltransitions. For example, Robock (1979) indicatedthat volcanic eruptions played a role in forcing "Lit-tle Ice Age". Well-dated high-resolution co…     

Relation between δ18O in atmospheric precipitation and temperature and precipitation

The paper analyzes the relation between δ¹⁸O and temperature and precipitation in different regions of the world on the basis of the data from the global observational network set by the International Atomic Energy Agency (I-AEA) and the World Meteorological Organization (WMO). The results show that there is the marked positive correlation between δ¹⁸O and temperature in the mid-high latitude continent regions, and the marked negative correlation between δ¹⁸O and precipitation in the mid-low-latitude ocean and coast stations.     

Variation of d δ18O/dT in precipitation in the Qinghai-Xizang Plateau

The relations between δ¹⁸O and temperature on the different time scales were analysed, according to the data from Tuotuohe (34°13′N, 96°25′E; 4533 m a. s. l.), Delingha (37°22′N, 97°22′E; 2981 m a. s. l.) and Xining (36°37′N, 101°46′E; 2261 m a. s. l.) in the Qinghai-Xizang Plateau. The results show that the significance of d δ¹⁸O/dT on different time scales are different. The d δ¹⁸O/dT on the synoptic scale reflects the interdependent relation between δ¹⁸O and temperature in the short-term synoptic scale process; the d δ¹⁸O/d T on the seasonal scale reflects the relation between them whithin a year; and the d δ¹⁸O/d T on the climatic scale reflects the relation between them in the long-term climatic change. The calculated d δ¹⁸O/dT on climatic scale is very close to the theoretical values on the condition of advection transport for Tuotuohe Station. However, there are great differences between the calculated and the theoretical values for Delingha and Xining stations.     

Compositions of δ18O and δ13C in various carbonates of core RM in the Zoigê Basin and climatic significance

The hole RM, the deepest one fully obtained core in the Qinghai-Xizang Plateau, situated in the depositional center of the Zoige Basin (33°57′N; 102° 21′E) in the northeastern Qinghai-Xizang Plateau with a depth of 310.46 m. From ¹⁴C dating and paleomagnetic stratigraphic study, the core RM can date back to 900 ka B.P.. In this paper we analyzed the compositions of δ¹⁸O and δ¹³C in various carbonates can date (snail, obstrode, chemical carbonate) in core RM and discussed preferably the paleoclimatic record by the proxies of δ¹⁸O and δ¹³C of chemical carbonate (authicarbonate) from core RM in the past 140 ka. The results showed that the values of δ¹⁸O in various carbonates are generally identical, and the values of δ¹³C in it are inconsistent, while there exist better relativity. The studies also demonstrated that there was a negative correlation between δ¹⁸O and δ¹³C of authicarbonate in core RM in the past 140 ka, showing that the changes of δ¹⁸O values were mainly relative to the water temperature. According to above, the climatic evolutionary sequence were rebuilt in the past 140 ka in the region.     

Isotopic evidence for holocene climatic changes in Bosten Lake, Southern Xinjiang, China

Based on the δ¹³C and δ¹⁸O fluctuation of lacustrine carbonate, CaCO₃ content and sporo-pollen data, a palaeoclimatic history of Bosten Lake during the Holocene has been outlined, several stages of climatic changes are divided, and the following result es are obtained: (1) Palaeoclimatic changes revealed by carbonate isotope around Bosten Lake are basically identical with that revealed by other geological records in Xinjiang. Environmental changes presented apparent Westlies Style model: during cold period, relative humidity increased, δ¹⁸O, δ¹³C and CaCO₃ appeared low; but in warm periods, the dry regime aggravated. (2) The temperature reflected by δ¹⁸O exist evident features being increase in the late period during the Holocene. Together with the δ¹³C, pollen and CaCO₃ analyses, several cold and warm phases which are of broad regional significance can be identified. The warm peaks occurred at about 11.0 ka B.P., 9.4 ka B.P., 7.5 ka B.P., 5.0 ka B.P., 3.0 ka B.P. and 2.0 ka B.P.; the cold peaks at 11.5 ka B.P., 10.5 ka B.P., 8.8 ka B.P., 5.5 ka B.P., 3.3 ka B.P., 2.2 ka B.P. and 1.5 ka B.P.. (3) Several climatic events with the nature of “abrupt climatic changes” are revealed in the periods of 11.0 ka B.P. −10.5 ka B.P., 9.4 ka B.P. −8.8 ka B.P., 5.5 ka B.P. −5.0 ka B.P. and 2.0 ka B.P. −1.5 ka B.P.. (4) The results show that carbonate isotopic record of lacustrine sediment in arid area is very sensitive to climatic changes, and may be play a very important role in understanding the features and mechanism of palaeoclimatic changes.     

The contribution of trace elements from seawater to chimneys： a case study of the native sulfur chimneys in the sea area off Kueishantao, northeast of Taiwan Island

Hydrothermal fluid containing abundant matter erupts from seafloor, meets ambient cold seawater and forms chimneys. So the main matter origins of chimneys are seawater and matter which are taken by hydrothermal fluid from deep reservoir. However, because of seawater’s little contribution to the forming of chimneys, it is usually covered by the abundant matter which is taken by hydrothermal fluid. Therefore, chimneys formed in ordinary deep seawater hydrothermal activity, containing complex elements, cannot ...     

Stable isotopes in aquatic food web of an artificial lagoon in the Hangzhou Bay, China

Stable isotope values, δ¹³C and δ¹⁵N, were determined for four primary producers and 19 dominant consumers in a small artificial lagoon located in Hangzhou Bay. Based on these results the major pathways for energy flow and trophic structure of the artificial lagoon ecosystem were characterized. The mean δ¹³C values for the 19 consumers ranged from −22.99‰ to −14.24‰. Apart from so-iny mullet Liza haematocheila, the other 18 consumers had intermediate δ¹³C values between those of epibenthic microalgae and particulate organic matter (POM). The results of a multiple source linear mixing model (IsoSource model) indicated that 50% or more of the organic carbon in the tissues of most consumers was derived from epibenthic microalgae. This indicated that these primary producers were the main food source fueling the lagoon food web. The mean δ¹⁵N values for the 19 consumers varied between 4.93‰ and 12.97‰ and indicated four trophic levels in the lagoon. Four macroinvertebrates and zooplankton represented the primary consumers, whilst the other 14 consumers occupied the secondary and tertiary consumer levels. The 19 consumers were divided into three trophic guilds (detritivores/suspension feeders, omnivores and carnivores).     

Application of transition metal isotope tracers in global change research

High-precision isotope composition determinations using multicollector, magnetic-sector inductively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research.The Mo isotope system may be useful in paleoredox investigations indicating that δ^97 ^95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded in δ^97 ^95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated from δ^97 ^95M0 values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation ( δ^56 ^54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.     

VARIATIONS IN ISOTOPIC COMPOSITIONS OF CHLORINE IN EVAPORATION-CONTROLLED SALT LAKE BRINES OF QAIDAM BASIN，CHINA

ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｌｏｒｉｎｅｈａｓｔｗｏｎａｔｕｒａｌｌｙｏｃｃｕｒｉｎｇｓｔａｂｌｅｉｓｏｔｏｐｅｓ,　35Ｃｌａｎｄ　37Ｃｌ.Ｓｅｖｅｒａｌｓｔｕｄｉｅｓｒｅｐｏｒｔｅｄｔｈｅｖａｒｉａｔｉｏｎｓｉｎｔｈｅｉｓｏｔｏｐｉｃｃｏｍｐｏｓｉｔｉｏｎｏｆｃｈｌｏｒｉｎｅｉｎｎａｔｕｒｅ.Ｈｏｗｅｖｅｒ,ｉｎｔｈｅｅａｒｌｙｙｅａｒｓＯｗｅｎａｎｄＳｃｈａｅｆｆｅｒ(1955)ｒｅｐｏｒｔｅｄｎｏｏｂｓｅｒｖａｂｌｅｄｉｆｆｅｒｅｎｃｅｉｎｔｈｅ　37Ｃｌ35Ｃｌｒａｔｉｏｓｉｎｔｅｎｓａｍｐｌｅｓｅｘ…     

ORIGIN OF CARBONATE MATERIALS IN THE NORTHERN BASIN OF LAKE BAIKAL AND ITS RELATIONSHIP TO HOLOCENE PALEOCLIMATE

Fine-grained disseminated carbonate was found in Holocene sediments in a core taken from the northern basin of Lake Baikal. The core had two distinct facies. a terrigenous blue-clay overlain by a diatomaceous silt. Oxygen and carbon stable isotope analyses, combined with SEM , X-ray diffraction and .palynology, show that the carbonate in the blue-clay layer is pedogenic in origin, rather than biogenic or authigenic . The S C values in the blue clay suggest that the carbonate is derived from a single source , while the carbonate in the diatom-rich layer might be transported by winds from different sources. On the assumption that the carbonate was formed during the post-glacial age and was transported primarily by river runoff, the 18O isotopic values suggest that the annual temperature in the northern Baikal drainage area was about 3℃ warmer during the middle Holocene (8500-7000 a, B. P.) than during the early Holocene (11 000-8 500a, B.P.) when the blue clay was being deposited . This interpretation is     

A 3600 years paleoclimatic change inferred from organic δ13C and TOC/TN of the Gucheng Lake sediments, southeast China

A 6.2 m thick core of Gucheng Lake sediment provided a 3600 years record of climate change. The contents of the TOC in the core changed from 2.63% to 8.48%, and the δ¹³C values of organic matter were from −21.54% to −27.3%. The TOC/TN ratios indicated that the organic materials in sediments were from lake plankton and land-derived plants. The 2.9–22 m core interval with high TOC/TN ratios, low δ¹³C values and low contents of TOC indicated a cold climate stage. The 6.2–5.5 m and 0.4–0.1 m intervals were characterized by low TOC/TN ratios, high δ¹³C values and high contents of TOC, and reflected temperate climate stages. Project 49372129 supported by NSFC.     

STUDY OF OKINAWA TROUGH SEDIMENTATION RATES AND PALEOENVIRONMENT BASED ON URANIUM SERIES ISOTOPE

Spectrometry of ~(238)U, ~(234)U, ~(230)Th and, ~(232)Th in three Okinawa Trough cores showed that, based on the~(230)Th/~(232)Th activity ratio, the sedimentation rates were about 2.5 cm/ka, 2.8 cm/ka and 8.5 cm/ka respectivelyduring the Holocene and about 20.1 cm/ka, 12.29 cm/ka, 8.8 cm/ka and 12.6 cm/ka respectively during theWurm glacial. To examine the past global climatic and oceanographic changes, the stable oxygen isotopesδ~(18)O and CaCO_3 were measured. The Th content and Th/U ratio showed that variations of terrigenous materialinput from the continental shelf were associated with glacial and interglacial changes and sea level     

Climatic Signals Recorded in Shells in Xingcuo Lake,Eastern Tibetan Platedu

ＩＮＴＲＯＤＵＣＴＩＯＮＱｕａｎｔｉｔａｔｉｖｅｅｘｔｒａｃｔｉｏｎｏｆｐａｓｔｃｌｉｍａｔｉｃｅｎｖｉｒｏｎｍｅｎｔｉｎｆｏｒｍａｔｉｏｎｉｓａｎｅｗｆｏｃｕｓｏｆａｔｔｅｎｔｉｏｎｉｎｔｈｅｆｉｅｌｄｏｆｇｌｏｂａｌｅｎｖｉｒｏｎｍｅｎｔａｌｃｈａｎｇｅｓ.Ｉｎｔｈｅｒｅｃｅｎｔ 1 0ｙｅａｒｓ,ａｓｅｒｉｅｓｏｆａｃｈｉｅｖｅｍｅｎｔｓｉｎｒｅ ｂｕｉｌｄｉｎｇｔｈｅｓｅｑｕｅｎｃｅｓｏｆｃｌｉｍａｔｉｃａｎｄｅｎｖｉｒｏｎｍｅｎｔａｌｅｖｏｌｕｔｉｏｎｓｉｎｖａｒｉｏｕｓｓｃａｌｅｓｈａｖｅ…     

New technique for study on isotopic fractionation between sea water and foraminiferal growing processes

The stable isotopic δ¹⁸O and δ¹³C composition of foraminiferal shell calcite varies as a function of many factors including temperature and salinity. In order to understand and interpret the variations in the isotopic composition of foraminiferal shell calcite, research has been recently focused on the role of the “vital effects”. Our examination of the lamella structure of several recent planktonic foraminifera indicates that the secretion of sequential lamellae results in multiple lamillae on earlier chambers and a single lamella on the final chamber. We used a very simple procedure to separate the individual whole test of foraminifera into several chambers and measured the isotopic composition of each growth stage chamber. The results indicate that the stable isotopic composition (carbon and oxygen), particularly that of the last two chambers, of the foraminiferal test varies as a function of the individual growing process. Contribution No. 1847 from the Institute of Oceanology, Academia Sinica.     

PROFESSOR ZHU KEZHEN OPENING UP A PATH FOR RESEARCH ON CLIMATIC CHANGE IN CHINA

ＰＲＯＦＥＳＳＯＲ ＺＨＵ ＫＥＺＨＥＮ ＯＰＥＮＩＮＧ ＵＰ Ａ ＰＡＴＨ ＦＯＲ ＲＥＳＥＡＲＣＨ ＯＮ ＣＬＩＭＡＴＩＣ ＣＨＡＮＧＥ ＩＮ ＣＨＩＮＡ ＳｈｉＹａｆｅｎｇ（施雅风）（ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＧｌａｃｉｏｌｏｇｙａｎ...     

Vegetation dynamics and its relationship with climatic factors in the Changbai Mountain Natural Reserve

This study examined the temporal variation of the Normalized Difference Vegetation Index (NDVI) and its relationship with climatic factors in the Changbai Mountain Natural Reserve (CMNR) during 2000-2009.The results showed as follows.The average NDVI values increased at a rate of 0.0024 year-1.The increase rate differed with vegetation types,such as 0.0034 year-1 for forest and 0.0017 year-1 for tundra.Trend analyses revealed a consistent NDVI increase at the start and end of the growing season but little variation or decrease observed in July during the study period.The NDVI in CMNR showed a stronger correlation with temperature than with precipitation,especially in spring and autumn.A stronger correlation was observed between NDVI and temperature in the tundra zone (2,000-2,600m) than in the coniferous forest (1,100-1,700m) and Korean pine-broadleaved mixed forest (700-1,100m) zones.The results indicate that vegetation at higher elevations is more sensitive to temperature change.NDVI variation had a strong correlation with temperature change (r=0.7311,p<0.01) but less significant correlation with precipitation change.The result indicates that temperature can serve as a main indicator of vegetation sensitivity in the CMNR.     

SEDIMENT DISCHARGE OF THE HUANGHE RIVER AND ITS EFFECT ON SEDIMENTATION OF THE BOHAI SEA AND THE YELLOW SEA

The Huanghe (Yellow) River, with annual sediment discharge about 11 ×108tons, contributes about 17% of the fluvial sediment discharge of world's 21 major rivers to the ocean because its middle reaches flow across the great Loess Plateau of China. Sediment discharge of the Huanghe River has a widespread and profound effect on sedimentation of the sea. The remarkable shift of its outlet in 1128-1855 A.D. to the South Yellow Sea formed a large subaqueous delta and provided the substrate for an extensive submarine ridge field.The shift of its outlet in the modern delta every 10 years is the main reason why with an extremely heavy sediment input and a micro- tidal environment, the Huanghe River has not succeeded in building a birdfoot delta like the Mississippi. The Huanghe River has consistently brought heavy sediment input to sea at least since 0.7 myr.B.P. Paleochannels, paleosols, cheniers and fossils on the sea bottom indicate that the Yellow Sea was exposed during the late Quaternary glacial low-sea l     

Paleoclimatic Change Inferred from Carbon Isotope Composition of Organic Matter in Sediments of Dabusu Lake, Jilin Province, China

Study on the organic compounds and stable isotope composition of a sediment section in Dabusu Lake revealed that the organic materials in the sediments came mainly from terrestrial plants brought into the lake by rtmoff.The δ^13 C of the organic materials had high values during warm-dry climatic stages and decreased in cold-wet stages.Analysis of data on carbonate content and ^14C age showed that the lake basin had experienced several wet-cold and warm-dry climatic cycles since 15000 a BP. Since 6700 a BP, the climate reached a relatively stable warm-dry stage,so that the lake water was gradually condensed and finally a saline lake was formed.     

Phytoplankton distribution and community structure in the East China Sea (ECS) continental shelf

ＩＮＴＲＯＤＵＣＴＩＯＮＰｈｙｔｏｐｌａｋｔｏｎｈａｓａｋｅｙｒｏｌｅｉｎｔｈｅｍａｒｉｎｅｅｃｏｓｙｓｔｅｍａｓｔｈｅｂａｓｉｃｐａｒｔｉｎｔｈｅｆｏｏｄｃｈａｉｎ ,ｗｈｉｃｈｉｓｉｍｐｏｒｔａｎｔｉｎｆｏｒｍａｔｉｏｎｆｏｒａｓｓｅｓｓｉｎｇｐｒｏｄｕｃｔｉｖｉｔｙｐｏｔｅｎｔｉａｌａｎｄｆｉｓｈｅｒｙｒｅｓｏｕｒｃｅｓ.Ｐｈｙｔｏｐｌａｎｋｔｏｎａｌｓｏｈａｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｔｈｅｃａｒｂｏｎｂｉｏｇｅｏｃｈｅｍｉｃａｌｃｙｃｌｅ,ｂｅｃａｕｓｅｉｔｃａｎａｂｓｏｒｂａｌａ…