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2017 Vol. 36, No. 2

Display Method:
The relationship between δ18O characteristics of the precipitation(heavy rainfall or rainstorm) and its water vapor sources in Guilin, China
ZHU Xiaoyan, ZHANG Meiliang, WU Xia, PAN Moucheng
2017, 36(2): 139-161. doi: 10.11932/karst20170201
Abstract:
It is significant to use stable isotopic of modern meteoric precipitation for the global or regional water cycle research, which is also important component in reconstructing paleoclimate in the studies of ice cores, lake sediments, stalagmites and the others. Oxygen and hydrogen stable isotopes (δ18O andδD) in the meteoric precipitation collected from each heavy rain event from January to December in 2012 in Guilin,are studied in this paper. The overall correlation between δ18O and δD is obtained as δD = 8.8 δ18O +17.96 from 132 stable hydrogen and oxygen isotope components. During the monitoring period, δ18O values of the meteoric precipitation varied -13.56 ‰ to +1.07 ‰ with an averageδ18O value of -5.78 ‰ (VSMOW) and theδD values of the meteoric precipitation are between -101.52 ‰ and +16.02 ‰ with an average of -41.03‰ (VSMOW).Using Backward Trajectory technology of the HYSPLIT model and the data of precipitation isotopes in Guilin, it was found that the water vapor sources of the meteoric precipitation in the summer time (May to October) is mainly controlled by the water vapor of the marine airmasses from the Indian Ocean or Gulf of Bengal and the South China Sea, secondly from the West Pacific Ocean. The δ18O value of the meteoric precipitation is more negative with average δ18O value of -8.02 ‰ (average of 64 groups) and accounts for 53.3% of the total meteoric precipitation. And the water vapor sources of the meteoric precipitation in the winter monsoon (November to the next April) are mainly affected by the warm-moist airmasses of the West Pacific Ocean and the continental cold air mass flow carried by the westerly wind zone (or the winter monsoon) and sometimes superposed by the part of the local evaporation moisture circulation. In this period, theδ18O value of the meteoric precipitation is more positive with average of -2.86 ‰ (average of 68 groups) and accounts for 46.7% of the total meteoric precipitation.The research results show that the stable isotopic composition of modern meteoric precipitation in Guilin is related to the monsoon type and source of the meteoric precipitation cloud and property of the meteoric precipitation. Theδ18O value of the meteoric precipitation from far transmission of water vapor of the marine air masses carried by the summer monsoon is more negative. In contrast, the δ18O value is more positive while the meteoric precipitation is controlled by the continental cold air mass flow carried by the westerly wind zone, or by the overlay of winter monsoon with localised air moisture circulation. These results indicate that the different sources of water vapor have significant influences on the δ18O variation of the meteoric precipitation. Therefore, analysis ofδ18O in the meteoric precipitation, especially its seasonal variation characteristics in turn reveals the water moisture sources of local meteoric precipitation.
Variation of the Asian summer monsoon during the MIS 5a/5b period inferred from a new high-resolution stalagmite record
ZHANG Taotao, LI Tingyong, HAN Liyin, CHENG Hai, LI Junyun, ZHAO Xin, ZHOU Jingli
2017, 36(2): 162-170. doi: 10.11932/karst20170202
Abstract:
Due to the paucity of the high-resolution records of the Asian summer monsoon (ASM) during the marine isotope stage (MIS) 5, our understanding about the ASM in this period is limited. In this study, a 38-yr resolution stalagmite oxygen isotope record from the Yangkou Cave, Chongqing, southwestern China, is used to reconstruct the detailed evolution of the ASM during the period of MIS 5a/5b. The Yangkou record exhibits a close correlation between the ASM and the climate of the North Atlantic at a centennial-millennial-scale. In terms of the precise 230Th dating with error less than 0.4%, the onset and termination of Chinese Interstadial (CIS) 22 are constrained to 91.2±0.3 ka BP and 88.9±0.3 ka BP, respectively, and the beginning of the CIS 21 is defined at 84.6±0.3 ka BP. In addition, the evolution pattern of CIS 22 and CIS 21 recorded in the stalagmite from the Yangkou Cave is slightly different from those recorded in NGRIP,which is anti-phased with the trend of temperature change in the Antarctica. We speculate that the ASM during MIS 5a/5b may be affected by climate variation in the southern hemisphere.
Climatic implications of stalagmite grey scale sequence during the Early Holocene from the Yangkou cave, Chongqing
CUI Guyue, YANG Xunlin, FANG Moqin, SUN Xili, SHI Zhichao, WANG Baoyan
2017, 36(2): 171-178. doi: 10.11932/karst20170203
Abstract:
One stalagmite (YK719) from the Yangkou cave at the Jinfo Mountains, Nanchuan in Chongqing is used as the research object in this article. The purpose is to reconstruct the climate change in the early Holocene with accurate 230Th dating results, δ18O and grey scale data. Comparison of the grey scale sequence and δ18O suggests that δ18O value was heavier during the weak monsoon period. Accordingly, the grey scale sequence shows a “trough-shaped” pattern. However, it showed “a crest” pattern when the monsoon was powerful. Furthermore, the grey scale value has a good correlation with the tree ring Δ14C data and the sunspot number, suggesting the solar activity is an important factor in controlling the variation of grey scale values. Solar activity might affect the grey scale value variation via temperature and monsoon precipitation,(1) The increase of temperature leads to the rise of soil microbial activity and a large amount of decomposed organic matter. Meanwhile, rock would be dissolved faster for the rise in the dissolved organic carbon and soil CO2. Thus, the relatively pure calcite would be deposited with darkish and transparent appearance. Otherwise, it would be opaque and milky; (2) Solar activity-induced changes in the North Atlantic floating ice may indirectly affect the Asian monsoon precipitation variation through the coupling of the monsoon and Eurasian snow cap in the early Holocene, so as to affect the change of grey scale values of stalagmites.
Flora and species diversity of epilithic mosses on rock desertification in the Puding karst area
CONG Chunlei, LIU Tianlei, KONG Xiangyuan, ZHANG Xianqiang
2017, 36(2): 179-186. doi: 10.11932/karst20170204
Abstract:
This work studied the flora and species diversity of epilithic mosses in karst rock desertification area in Puding,Guizhou Province. The results show that there are 8 families,24 genera and 54 species of epilithic mosses. Among them, the pottiaceae and hypnacea are the dominant families. Barbula, btyum, campylopus, pseudosymblepharis broth and rhynchostegiella are dominant genera. There is significant change in richness index of species,ranging 0.471 to -0.297.The evenness index is inconspicuous,which ranges from 0.671 to 0.566; and the abundance of the epilithic mosses in the ecologically damaged area is significantly lower than long-term observation of samples(E) of soil and water conservation. There are 4 types of life forms, including cluster pattern (53.8%), wefts (26.9%), mats (11.5%) and pendants (7.7%),in which the cluster pattern is absolutely dominant. The result of PCA shows that through quadrat analysis, the ecology and distribution of the epilithic mosses are different.
Carbonic anhydrase activity of six epilithic mosses and their underlying soil in the Puding karst area,Guizhou Province
LIU Tianlei, CONG Chunlei, HU Dan, WANG Shijie, ZHANG Xianqiang
2017, 36(2): 187-192. doi: 10.11932/karst20170205
Abstract:
The samples of six moss plants include B.argenteum, B.unguiculata, E.julaceum, E.leptothollum, R japonicum and T vermicularia were collected from the karst rock desertification area in Puding of Guizhou, as the objects of this study. The carbonic anhydrase (CA) activity of the epilithic plants and the matrix of soil was studied, from which the analyses of bio-karst mechanism and governance of ecological environments in karst rocky desertification areas can be performed.The results show that there are some differences in carbonic anhydrase activity of six epilithic plants.The E. leptothollum is highest, reaching 272.99 U·g-1(FW), while the minimum is 33.45 U·g-1(FW) in R. japonicum. The B.argenteum base soil CA activity(101.81 U·g-1(dry soil) is the highest. The E. leptothollum is 15.95 U·g-1 (dry soils) as the lowest. It could be concluded that CA activity has positive correlations with plant and soil carbonic anhydrase content of total phosphorus, kalium, gravel and soil moisture, respectively.
Archaeal community structure and diversity of the carbonate rocks in karst regions, Guizhou:A case study of the Nanjiang canyon
TANG Yuan, LIAN Bin, CHENG Jianzhong
2017, 36(2): 193-201. doi: 10.11932/karst20170206
Abstract:
Guizhou is one of the three largest karst regions in the world where vast expanses of karst develop well. The carbonate rock area is 13×104 km2, covering 73% of total land surface area of the province. Carbonate rock is very challenging for organisms to live in it owing to its features, such as arid environment, nutritional deficiency, and great temperature fluctuations. However, there are various microorganisms on its surface and in its cracks, which play a crucial role in biogeochemical cycle. The Nanjiang canyon is a typical karst canyon, which is praised as "Karst Ecosystem Museum". It is located in Kaiyang County of Guizhou Province, southwestern China. And there are a lot of exposed carbonate rocks in this area. In order to study the archaeal diversity of carbonate rocks in Guizhou karst areas, we investigated the archaeal community structure in dolomite and limestone rocks from Nanjiang canyon using 16S rDNA gene clone libraries combined with Restriction Fragment Length Polymorphism (RFLP) analysis. Genomic DNA of rock samples were collected using the UltraCleanTMSoil DNA Isolation Kit. PCR amplification of the archaeal 16S rRNA gene was performed using universal primers 27F and 958R. The PCR products were ligated into the pGEM-T Easy Vector SystemⅠand transformed into competent E.coli JM109 cells and then constructed the dolomite and limestone clone libraries. Randomly selected 300 positive clones from each clone library were identified by RFLP with restriction endonuclease Msp I. In total, 14 and 13 genotypes were obtained from dolomite and limestone clone libraries, respectively. The rarefaction curves indicate that the major part of the diversity in the clone libraries was covered. The coverage C values of dolomite and limestone clone libraries are 95.4% and 91.3%, and Shannon-Wiener indexes are 2.14 and 1.93, respectively. The diversity of indexes shows that the diversity of archaea is much lower than the bacterial and fungal diversity, and the archaeal diversity of dolomite is slightly higher than that of limestone. The phylogenetic analysis reveals that all clones from the two clone libraries are affiliated to the phylum Crenarchaeota. The similarities between the representative clone sequences from carbonate rocks and their closest sequences deposited in GenBank range from 96% to 100% and all of the matches are from uncultured archaeal clones. Meanwhile, most of the archaeal sequences are closely related to environmental clones from soil and rock environments.
Spatiotemporal variations of soil physical characteristics in rocky desertification areas of Guizhou karst-cluster depression
LI Anding, GUO Chunyan, FU Yuhong, LONG Xiuqin
2017, 36(2): 202-206,241. doi: 10.11932/karst20170207
Abstract:
The karst peak cluster depression is ranked as the second place of eight rocky desertification control areas in our country, which is of 3.1 million hm2. Guizhou province is the region with most serious rocky desertification nationwide. In combination of field investigation with laboratory analysis and using SPSS19.0 statistics method, this work focused on the change of soil physical characteristics in different seasons and different landform parts of this region. The results show that,(1) There is big spatial and temporal differentiations. Besides a few loci with weak variation, others are characterized by medium degrees of variation related to complex and varied habitat types and heterogeneity of habitat height. (2) Soil physical characteristics do not change significantly with slopes, while showing prominent variations in different landforms (upper, middle and lower slopes) and different seasons (spring, summer, autumn, winter). (3) For different vegetation types, in addition to the non-capillary porosity, soil physical characteristics such as natural water content change significantly. In the areas with shrubbery and secondary woodland (economic fruit woods), the soil is relatively loose and the permeability is good, while in the coniferous forests or grassland areas, the soil is viscous and heavy, and the permeability is relatively poor.
Variation of hydrochemical characteristics and the ion source in the upstream of Guijiang river:A case study in Guilin section
DU Wenyue, HE Ruoxue, HE Shiyi, SUN Ping’an, MO Jianying, Qin Xinxing, Yu Shi
2017, 36(2): 207-214. doi: 10.11932/karst20170208
Abstract:
In order to discuss the hydrochemical composition variation and the source of dissolved ions in the upper stream Guijiang river, observations and sampling were undertaken in October 2013 to April 2015. The results show that the hydrochemistry type of Guilin section is of HCO3-Ca type. Ca2+ and HCO3- are the main cations and anions, which are mainly from the weathering of carbonate rocks in the basin. The concentration of ions is controlled by the river flow, which is higher in the winter while low in the summer. Meanwhile, the sulfate also takes part in the carbonate weathering in the basin.The hydrochemistry of Guijiang upstream is controlled by carbonate as well as silicate rocks, even though there is much limited carbonate rocks occur in the basin. Analysis of principal compositions shows that the contribution ratio of the first factor is 38.8%, well correlated with K+, Na+, Mg2+, Cl-, SO42- and NO3-, representing the influence of human activity and precipitation on the water. And the contribution ratio of the second factor is 28.2%, including HCO3-and Ca2+, which indicates the solution of carbonate rocks. In addition, there is no significantly effective load indicator of the third factor.
Hydrogeochemical characterization of groundwater and surface water and their influencing factors based on principal component analysis: An example in the Shuicheng basin of Guizhou
YE Huijun, ZHANG Ruixue, WU Pan, LI Xuexian, QIN Yingji, ZHA Xuefang, HAN Zhiwei
2017, 36(2): 215-225. doi: 10.11932/karst20170209
Abstract:
As the major water resources for most of the settlements in karst regions, karst water could be more easily polluted in a shorter time by human activity than water in non-karst aquifers. Assessing current hydrochemical status and understanding the mineralization process in karst water are of significance to analyze the influence factors from natural evolution and human activities. The Shuicheng basin, a tectonic basin with well-developed karst topography, is located at the center of the Yunnan-Guizhou Plateau, southwestern China. The NW-SE oriented basin is an area of approximately 22.5 km long, 5.5 km to 9 km wide and 208 km2 in size, with the elevation ranging from 1,700 m to 1,800 m above mean sea level. Climatically, it falls in the north subtropical monsoon zone with plentiful precipitation which is a major source recharging the karst water. Average annual precipitation in this area is 1,200 mm/year to 1,500 mm/year. Geologically, the basin predominantly consists of the Permian and Carboniferous carbonate rocks, accounting for nearly 90% of the total rock exposure.This work investigated the hydrogeochemical characteristics and influence factors of groundwater and surface water in different regions of the Shuicheng basin, with the intension of providing references for helping to significantly improve the quality of the aquifer. Sampling campaigns were carried out in September 2015. Variable parameters of the sampled water were measured using a portable instrument and HCO3- was titrated with 0.01 mol/L HCl in the field. All water samples were filtered through 0.45 μm cellulose acetate membrane filters and then collected into 50 mL high-density polyethylene bottles. The samples for cation analysis were immediately acidified with pure HNO3 to a pH lower than 2. The cations and anions of the samples were analyzed by the methods of atomic absorption spectrometry and ion chromatography, respectively, with the test accuracy of less than 5%.The interpretation of hydrochemical data was performed by using various methods, i.e. Piper diagram, correlation analysis, multivariate principal component analysis, and saturation mapping. The results show two hydrochemical types (HCO3-Ca and SO4-Ca) that characterize the groundwater and surface water. Natural dissolution of carbonate rock (water-rock interaction) is the primary source of Ca2+and HCO3- in groundwater and surface water. Domestic sewage and the wastewater from livestock and poultry industry may be the main contribution of Cl-,NO3-and Na+ to surface water. The main factor affecting on the quality of groundwater is the water-rock reaction. The urban sewage water from Zhongshan district and coal industrial wastewater from Shuicheng County and discharge from the groundwater are the main sources affecting the surface water quality of the basin. In conclusion, the evolution of water quality is determined by the lithology of the aquifer (dissolution and base exchanges) and by anthropogenic processes (urbanization, coal mining activities and agriculture).
Tracer tests on distribution and structural characteristics of karst channels in Nandong underground river drainage
ZHAO Yi, LI Yanqing, QIN Xingming, HONG Tao, CHENG Ruirui, LAN Funing
2017, 36(2): 226-233. doi: 10.11932/karst20170210
Abstract:
The high precision tracer tests were carried out to delineate the distribution of part karst channels in the Nandong underground river drainage and to analyze their structural characteristics. The results show that the No.1 underground stream has an independent water system, with its recharge area around Wabaibai. The chief channels of No.2 underground stream are overall towards to Yongning and Shidong. The channels of No.3 underground stream lead to Chenghongzai. The channels of No.2 and No.3 underground streams meet each other nearby Nandong outlets where the No.2 stream supplies No.3 stream during dry seasons. In addition, No.1 and No.2 underground streams present morphology of old and adult ages, respectively, and their courses are relatively fluent. Whereas, the No.3 underground stream developed later and has some cracks nearby its outlet. Finally, this paper infers and maps the general distribution of karst channels based on the existing data and the hydrogeological conditions in the drainage, providing a theoretical basis for the future karst hydrogeology surveys, geophysical prospecting, drilling and groundwater exploitation and utilization in this region.
Study on the regional evapotranspiration over different surface conditions of the Longzici spring drainage
SHEN Haoyong, LIANG Yongping, CHENG Yang, HUANG Chunling
2017, 36(2): 234-241. doi: 10.11932/karst20170211
Abstract:
The Longzici spring system, one of the largest karst spring in North China, is located in the western margin of the Linfen basin, covering an area of 2,250 km2. The springs discharge at an annually average rate of 4.81 m3/s derived from the records from 1955 to 2013. The karst water has been an important source for local water supply. But now the spring flow dramatically degrades because of climate change and human activities. Precipitation is the main source of the spring water recharge. This recharge occurs in two ways, namely the infiltration of precipitation over the carbonate rock areas and linear leakage of stream and river water. So it is very important to evaluate the recharge of karst water through an afforestation project. Based on NOAA/AVHRR data, the daily and monthly evapotranspiration (ET) of the Longzici spring are estimated during the period of 2014.4-2014.10, using surface energy balance system (SEBS) and the data of meteorological stations in Linfen. The ET has a monthly average value of 99.21 mm, with the maximum monthly value of 197.26 mm in June and the minimum one of 40.49 mm in April. In addition, the regional ET over different lithology and vegetation coverage rates are analyzed through spatial overlay. The results indicate that the ET increases with the increasing vegetation coverage rates in the carbonate rock outcrop regions, while it is the lowest in the medium vegetation coverage rate of clastic rock regions. Overall, the ET in the clastic rock regions is higher than that in the carbonate rock outcrop regions. If only ET is taken into consideration, keeping the medium vegetation coverage rate in clastic rocks will be favorable to increasing of recharge of karst water and afforestation in carbonate rock areas will enhance ET but not favorable to recharge from rainfall infiltration.
Leakage mechanism and comprehensive prevention control technology of tailing pond in karst areas
CHENG Feng, SU Xiazheng, ZHOU Jiejun, GUO Shangqi
2017, 36(2): 242-247. doi: 10.11932/karst20170212
Abstract:
The tailing pond leakage in karst area is one of the main reasons which cause environment pollution by mining. Because the impact mechanisms are complex and the governance is difficult, it has become a major hidden danger in mining development. This work took the tailing pond of the Beishan lead-zinc mine as the research area. The formation and failure mechanisms of deep and shallow leakage were studied through investigating and analyzing the geological structure of tailings, karst development characteristic, engineering geologic conditions, hydrogeological conditions and other factors in the karst area. The results show that the main reason of tailing pond leakage is the bottom rock-soil mass penetrated by high voltage. The leakage areas are harnessed by bolt plugged technique,leak paths sealed by organic filling materials, groundwater diverted, slope surfaces protected, among other measures. After engineering treatment, it proves that the anti-seepage result of the leakage area is good.
Pollution characteristics of heavy metals in soil of lead-zinc mining in karst areas
DENG Qin, WU Di, QIN Fanxin, YANG Zhen, JIA Yaqi, CHENG Zhifei, LIU Pinzhen
2017, 36(2): 248-254. doi: 10.11932/karst20170213
Abstract:
This study focused on the heavy metals in soil in DX and DW lead-zinc areas. By using the methods of atomic absorption spectrometry (AA800), atomic fluorescence spectrometry(AF-640) and other instruments, we measured the contents of heavy metals,including zinc(as Zn), mercury(as Hg), chromium (as Cr),cadmium (as Cd),copper (Cu), nickel (Ni), lead (Pb)and arsenic (As).By means of the single-factor pollution index and Nemerow index methods,we compared the pollution characteristics in the soil.PPC statistics were used to analyze the correlation of heavy metal pollution in the soil.The results indicate that heavy metals in soil have caused single or complex pollution and the soil was heavily polluted by Cd in the two areas. The Nemerow indexes in these two areaare 27.61 and 63.54, respectively, implying that the soil was highly polluted and such contamination in the DW area was more serious than the DX area.Except for Ni, the other seven heavy metals in the DX are correlated with each other,which is likely related to polymetallic accompanying and symbiotic deposits in the mining area.The total content of heavy metals and the pH have no significant correlation in the soil. The established models show high fitting precision and the research results can provide evidence for rehabilitating the polluted land in mine areas and setting corresponding management measures.
Comparison between the Xingwen karst area and South China karst region on tourism resources
WANG Xinggui, SHUI Wei, CHEN Yiping, LAN Xiaoxiong
2017, 36(2): 255-263. doi: 10.11932/karst20170214
Abstract:
The most representative karst topography and landform in China is concentrated in the South China karst, and the Xinwen County which is located in the South China karst region has the intact karst landscapes rarely seen throughout the country. Its rich and unique karst landscapes were defined by professor Zhu Xuewen, a member of Chinese Academy of Geological Sciences, as "Xingwen-type karst". In order to summarize its comparative advantages, the comparative research methods and Delphi method combined with AHP methods are employed to compare Xinwen karst, World Natural Heritage South China Karst projects and their typical karst tourism resources,including tiankengs, caves and stone forests. The results show that there are karst resources of many types, abundant features, high quality, good combination and concentrated distribution as well as unique karst ecological Bo and Miao cultures in the karst basins of Xinwen County. And the "Xingwen-type karst" has the same representation as the seven representative sites of World Natural Heritage South China Karst, which makes its resource conditions that entry the world heritage to further improve World Natural Heritage South China Karst.
Statistical analysis of show cave scenic areas (spots) in China
CAO Xiang, YANG Xiaoxia, LI Xi, XIANG Xu, SUN Xiaobei
2017, 36(2): 264-274. doi: 10.11932/karst20170215
Abstract:
China has rich show cave resources. Show cave scenic areas (spots) develop fast, but basic data of show caves updates slowly. It is difficult using the old data of show caves (analysis in 2005) to serve the academic research and development management of cave tourism. In order to solve this problem, this paper makes a statistical analysis on the basic data of Chinese show caves. The geographical scope of the statistics involves 31 provincial administrative regions in mainland China, excluding Taiwan, Hong Kong Special Administrative Region and Macao Special Administrative Region. Cave tourism columns have been searched over to find out numbers, quality, opening time and spatial distribution, development themes, and ticket prices of show caves in China through Chinese karst cave database, scenic spot lists of Chinese provinces and cities, Tong Cheng web site (www.17u.net), Xin Xin travel web site (www.cncn.com), and other related websites and newspapers. Analyzing these data by Excel and ArcGIS10.3 leads to the conclusions as follows,until July 2016, there are 364 show cave scenic areas and 344 show cave scenic spots (708 in total) in mainland China, including 177 A-grade show cave areas. And the distribution of them is across the nation,including 29 provincial administrative regions, except Shanghai and Ningxia. Show cave scenic areas play an important role in tourism. They include 2 parts in world natural heritage, 6 parts in world geological park, 24 parts in national geological park and 26 parts in national scenic area. The opening of show cave areas (spots) began in the 1970s and has a history of more than 40 years. From 1980 to 2008, many show cave areas (spots) have been developed, with fragmented time distribution. Regional karst geological backgrounds and economic development levels are different. The spatial distribution of show cave scenic areas (spots) has a trend of condensation, especially in the southwest, middlesouth, southern and eastern part of China. The developing themes of show cave scenic areas can be summarized as geological tourism, historic sites, religious activities, health care, under-ground river rafting, science education, and other creative types. Ticket prices of 5A-, 4A-, 3A-, and 2A-grade show cave scenic areas are 129, 86.16, 53.09, and 37.19 yuan RMB, respectively, and are higher than other ordinary scenic areas with same grades.
Temporal and spatial characteristics of network attention to show cave:A case study of five beautiful show caves
HE Xiaoqian, ZHANG Yanrong, LIU Yu
2017, 36(2): 275-282. doi: 10.11932/karst20170216
Abstract:
Cave tourism is an important form of tourist activities, which refers to the natural karst cave as the basis, through the transformation and utilization of caves, to carry out sightseeing, adventure, entertainment, medical and other tourist activities. Tourism resources of karst caves are very rich in China, where more than four hundred karst caves have been developed for tourism purpose. They are the most representative show caves in China which are selected in the most-beautiful-show-cave activity in 2005. Network attention rate of tourists is an intuitive measurement of their demand conditions and behavior habit on the Internet. Analyzing the spatial and temporal characteristics of network attention to show caves and their causes facilitates to delineate current development of show caves and the diversity of tourism demands, which can provide scientific guidance for the development of karst cave tourism. Based on the methods of Baidu index, statistical variation coefficients and Gini coefficient, this paper analyzes temporal and spatial characteristics of network attention rate to show cave in China. Time dimension analysis includes two levels, year and month. Spatial dimension analysis is on a provincial basis, to explore the inter-provincial differences of the attention. The results show that the network attention to show cave is of a high degree and shows a tendency of growth. The monthly changes exhibit a double M-shaped curve. The provincial differences of network attention are obvious. The provinces with higher attention concentrate in native places, neighboring provinces and economically developed eastern areas. This research also indicates that there is strong coherence between the fluctuation of network attention to show cave and seasonal differences of tourism activities. The attraction and attraction scope of karst cave resources are provincially different. The research provides some enlightenment for the development of cave tourism, for which more attention should be paid to the role of internet in the marketing of karst caves, take the network attention rate as an important measure for the management of show cave, and strengthen the cooperation with surrounding scenic spots.