The symposium took place in the Fengyu Karst Resort in Lipu county, 120km south of Guilin,Guangxi Province. The site is characterized by picturesque tower karst developed on Upper Devonian limestone, which is backed by allogenic water from Yaoshan Mt., a Lower Paleozoic noncarbonate basement of Caledonian Orogeny. A 5 km long underground stream cave system is developed under the stone peaks. 79 people from Japan, Russia, USA, Vietnam and China attended the meeting. The 5 days symposium included two days paper presentation, half day general discussion, and two and half days field excursion. In the opening ceremony,Sat. April 26 morning, Mr.Mo Yanping, the Governor of Lipli County made a warm welcome speech. Prof. Yuan Daoxian, the IGCP 379 project leader summarized the new development of the Project in the later part of 1996 and early 1997. Prof. Hu Haitao, member of Chinese Engineering Academy gave a lecture on the modern trend of environmental geology.The 125 pages IGCP 379 Newsletter 1997 was given to every participant. 47 papers were presented in 6 sessions as follows:

1. carbon cycle in karst processes : 10 papers

2. paleoclimate reconstruction with karst records : 5 papers

3. biogenic processes in karst soil, and carbon cycle in oil-gas reservoirs : 7 papers

4. regional karst correlation : 10 papers

5. environmental problems in karst (including reservoir building,cave Radon and

CO₂, and speleotherapy): 6 papers

6. foundation engineering in karst ( pile, grouting and etc.) : 9 papers

CARBON CYCLE IN EPIGENIC KARST PROCESSES.

Prof. Kazuhisa Yoshimura of Kyushu University, Japan gave a paper entitled" the geochemical cycle of carbon dioxide in a carbonate rock area, Akiyoshi-dai plateau, Yamaguchi, southwest Japan". He found a 1-2 months time lag of calcium concentration peak in karst water from the relevant soil CO₂ concentration peak (Fig. 1. in Attachment). The Chinese people get the similar results from their monitoring data (Fig.2 in Attachment). Moreover, based on the data from Akiyoshi-dai, Kazuhisa estimates the annual global removal of CO₂ from the atmosphere by carbonate rock dissolution as 8.9£E 10e8 t/a. During the excursion of April 30,1997 at Yaji Karst Experimental Site, 9km east of Guilin, field facilities to monitor the carbon cycle in a CO₂-H₂O-CaCO₃ karstdynamic system were shown.

THE DEEP SOURCE CO₂

Dr.Do Tuyet(The Inst. of Geology and Mineral Resources of Vietnam) reported that there are many geothermal springs in Vietnam along the northwest oriented plate margin zone. 'I'he hotest one is at Bang, Le Chuy district of Guang Pinh province. It is 105 degree in Centigrade, with many calcareous tufa, showing CO₂ outgassing. 'I'here are also many geothermal springs at the eastern side of Taiwan Island, China. Prof. Kazuhisa Yoshimura , Dr.Ching-Nan Liu (Taroko National Park Headquarter, Taiwan, China) and others reported one of the systems along Liwi Hsi River, north of Hualien county. A 20m high tufa cascade is found along a karst spring, outflowing from metamorphosed limestone near Changchun Temple. Dr. A. V.Petukhov (Industrial Institute, Ukhta,Komi Republic, Russia) put forward some new ideas of karst processes and carbon cycle in a carbonate rock oil-gas reservoir, which are related to the reduction of sulphates by hydrocarbons under the high pressure of tectonic movement. The reduction of sulphates by hydrocarbons will produce both H₂S and CO₂ , and thus intensify karst processes in the overlying carbonate strata. The ideas come from the occurrence of abundant H₂S in many oil-gas field in the world, and are testified by laboratory experiments.

PALEOCLIMATE RECONS'I'RUC'I'ION WITH KARST RECORDS

Dr.Hong-Chun Li (Department of Earth Sciences, University of Southern California, USA) presented a paper entitled "speleothem as high resolution paleoclimate and paleoenvironment records". He considers the ¹³C value of speleothem is mainly controlled by the isotopic composition of soil CO₂ coming from C3 or C4 plants. When the ¹⁸O and ¹³C shift to more negative value, it means a high C3/C4 ratio, and indicates wet climate, increased precipitation, and development of forest, and vice versa. With this ideas, he analysed the isotopic data of a 13cm stalagmite taken from Shihua Cave, western Beijing, and got 6 apparently climate cycles during the last 3,000 yr in Beijing. The wet period were peaked at 2860, 2350, 1850, 1480, 690 and 150 yr BP respectively, with a cycle time of about 500 years ( Fig.3 in Atachment). The heavier trend of ¹³C after 600 yr BP is considered to be the result of deforestation influenced by human activity around Beijing area, and thus reduced the C3/C4 ratio. The results are in good agreement with historic records, and tree ring data. Dr. Tan Ming(The Inst. of Geology, CAS) reported his investigation on the transparent microbanding and stable isotopes data from the same stalagmite of the Shihua Cave in western Beijing, with which he got annual variation of precipitation during the past 1200 years. In south China, Dr.Li Bin(The Inst. of Karst Geology, CAGS) analysed the 32,000- 1 1,000 yr BP interval of No. 1 stalagmite from Panlong Cave, 37 km south of Guilin with luminescene spectra and AMS C¹⁴ dating. He claimed that the Heinrich 1,2,3 and the Younger Dryas events are identifiable . In the excursion of April 30,1997, the sampling sites in Panlong Cave were visited.

REGIONAL KARST CORRELATION

Dr. Do Tuyet presented a paper "overview on karst of Vietnam". A map showing karst areas of Vietnam, and the geological, climatic, and biogenic origin of karst formation in Vietnam were given. The specific features of 5 major karst regions in Vietnam characterized by tropical karst were described with a series of colour slides. Participants was attracted by the unique coastal tower karst of Halong Bay. Many new findings in karst of both south China and north China were also exchanged.

PRACTICAL PROBLEMS IN KARS'I'

A special session dealt with various practical problems in karst such as leakage from reservoir, protection of karst sceneries, environmental problems in cave, karst ecological problems, and foundation problems in karst. Thc session was highlighted by the discussion on the experiences of serious surface karst collapse caused by dewatering in Fankou Pb-Zn Mine, Guangdong province and its remedy measures.

EXCURSION IN THE FENGYU UNDERGROUND STREAM CAVE SYSTEM

On April 28, a full day excursion was made in the underground world. The cave system is characterized by big halls and long underground stream. Participants were attracted by a 9m high rod-like stalagmite with an uniform diameter of only 10cm, and many big palm tree shaped stalagmites, with the length of a single "palm leaf" up to half meter. The hydrodynamic origin of such unique speleothem was one of the topics of enthusiastic discussion in the excursion. Some bilateral cooperation were initiated (Fig.4 in Attachment) . The excursion was ended with a 3.3 km long boat trip on the underground stream, which Prof. D.Ford of McMaster University, Canada, the former president of UIS regarded as "the longest boat ride that I have encountered in a tourist cave".

IGCP 379 BUSINESS MEETING

The meeting was held on Sun. April 27 afternoon, and chaired by the Project leader Prof. Yuan Daoxian. 12 participants from Japan, Russia, USA, Vietnam and China were at the event. The achievements of IGCP 379 and many good papers in the symposium were appreciated. Prof. Kazuhisa Yoshimura reported the works of Japanese National Working Group of IGCP 379, and suggested the Project to have a meeting in Japan. Dr.Hong-Chun Li (USC, USA) expressed his willingness in helping the organization of the Project’1998 meeting in Las Vegas, and will make 3-4 contributions for the Project in the next 3 years. Dr.DoTuyet reported the works of Vietnamese National Working Group of IGCP 379. He said the water resources in the karst region of northwest Vietnam is a big problem, and invited karst experts coming to Vietnam to give advice. Prof. Pan Genxin (Nanjing University of Agriculture) emphasized the importance of field monitoring in the Project’s future work. Participants fully supported the ideas to cooperate with IHP, as in many cases the carbon cycling and karst processes will not take place without water. There are already projects in some countries that make good integration between hydrogeology, geochemistry and carbon cycle. Some foreign friends appreciated the geological advantages in China for the Project's implementation, and future bilateral cooperations were discussed.

Figure1     (a)Daily data of the calcium concentration and discharge of the groundwater
Issuing from Akiyoshido Cave (1985-1986) [8]. : at baseflow; ·9 :at storm flow.
(b) Seasonal change of the soil CO₂ concentration in the grassland in Akiyoshidai Plateau (1995-1996; Depth: 40cm) [9]. ( by Kazuhisa Yoshimura )

Figure 2     Seasonal variation and relationship between soil CO₂, water Ph, HCO₃,
and monthly mean precipitation at Yudong underground stream, Zhenan country, Shanxi Province, China

Figure 3     d ¹⁸O and d ¹³C profiles of stalagmite S312 from Shihua Cave, Beijing,
China and their interpretation of paleoclimate ( by Hong-Chun Li, USC )

Figure 4     Dr.Hong-Chun Li of USC was collecting water samples with his Chinese
partners during the excursion in Fengyu Cave, Lipu.

REPORT ON IGCP379 ACTIVITY 1997

Researchers of the Karst Research Institute were active in IGCP-UNESCO Project No. 379: Karst Processes and the Carbon Cycle (World correlation of karst processes and their relevance with the carbon cycle) as followed:

-to observe the CO₂ content in different depth of the soil, perforated tubes were put into the ground above the Postojnska jama caves;

-the CO₂ content in tile air of Postojnska Jama and Škocjanske jame caves were observed too;

-by the means of physical and chemical analyses the rate of solution of carbonate rocks and the rate of flowstone deposition in the vadose zone were measured on the Slovene karst;

- the dynamics of tufa deposition was observed along one surface stream in Slovenia;

- the results obtained on the karst of Slovenia were compared by those from the Yunnan karst, in the Lunan region;

- the new group of researchers (of Jozef Stefan institute of physics) was included into the project, their research consists of observing CO₂ changes from the surface to the karst underground, using galleries of Postojnska jama caves.

Andrej Kranic(Karst Research Inst. of Slovenia)

The followed is a list of publications made by the Spanish group of the 379 project which are already accepted to publish and printing (when we have the off-print, we will send you a copy):

- ANDREO B. & CARRASCO F (in press): Application of the geochemistry and the radioactivity in the hydrogeological investigation of carbonate aquifers (Sierras Blanca and Mijas, southern Spain). Applied Geoclietnistry

- CARRASCO, F., ANDREO B., DuR°E N J.J., VADILLO I. & LINAN C. (in press):

Human influence on the karst water of the Nerja cave (Malaga, southern Spain). In: Karst Hydrogeology,Human Activities (D. Drew & H. Hotzl, eds.) International Contributions to Hydrogeology, vol. 20.

-ANDREO B., CARRASCO F., CUENCA J.,TÉWLLEZ A. & VADILLO I. (in press)El karst en los máWrmoles alpujáWrrides de las Sierras Blanca y Mijas (provincia de MáWlaga). In: El karst en Andalucia (J.J. DuráWn & J. LóWpez-MartíWnez, eds.)

-CARRASCO F.,DUR°E N J.J. & ANDREO B. (in press): Consideraciones sobre el karst de Nerja. In: El karst en AndalucíWa, (J.J. DuráWn & J. lóWpez-MartíWnez, eds.)

Currently, we continue working and we have 2 paper prepared for publishing

File: L:\IHEP)\Receive\9.D 6/26/98, 11:46:50PM

impact on the Nerja cave system (Malaga, southern Spain) (subbmitet to Hydrogeology Journal)

- ANDREO B., MARTIN-MARTIN M. & MARTIN-ALGARRA:

Hydrochemistry of the spring associated to travertines.Example of the Sierra Alfaguara (Granada, Southern Spain), It will be sent to Comptes Rendues Academie Sciences. Paris.

Sincerely yours

Bartolome Andreo & Francisco Carrasco

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Bartolotme Andreo-Navarro
Departamento de Geologia
FAcultd de Ciencias
Universidad de Malaga
29071 Malaga

SPAIN

TeléWfono 34-5-21,32004
Fax 34-5-2132000

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Boris Mijatovic (Yugoslavia)

In spite of the devotedness to the consideration of mostly inorganic species for a net source or sink of atmospheric CO₂, some further considerations are given to the transformation of organic substances. The cycle of carbon in natural waters is especially important because it is interrelated with the cycles of all other elements. In figure 1 are presented the all possible; rates of turnovers of the carbon in 10¹⁵ moles/year, what is the quantity of carbon on the earth's surface.

Figure 1.     The circulation of Carbon dioxide in natural conditions
(Stumm and Morgan, 1970.)

The circulation of carbon in natural conditions is determined primarily by biochemical reactions. In 1993. Goldshmidt made quantitative estimates on the amount of carbon in the different parts of the cycle. ³⁴s data have been revised by various workers. Although the estimates given for the annual turnover are quite uncertain, they clearly illustrate that most of the carbon in the earth's surface has been cycled through organisms. (Stumm and Morgan, 1970.).

The organic material produced in the world coastal zones (oceans), furthermore, constitutes one of man's most significant marine environment resources.

Discussion of the organic chemistry of natural waters is appropriate because of its thermodynamic instability under aquatic conditions, and may be considered as intermediates in the continuous and complicated circuit of redox reactions. Despite its importance, the chemistry of aqueous organic matter is one of the least well-know domain in the chemistry of natural waters.

Experimental demonstration that certain organic substances can markedly modify grouwth rates of microorganism has emphasized the importance of organic constituents. Progressive concern with pollution has also stimulated research on this domain.

Despite many years of research, it is still not possible to satisfactorily balance the disturbed global carbon cycle. The global ocean is recognised as one of the major skins for fossil and biogenic carbon released to the atmospheric by human action. Several mechanisms (or exchange) are involved in the uptake of CO₂ by the ocean (Figure 2). One is the net CO₂ uptake in the mixed surface layer by thermodynamic equilibration in response to the rising CO₂ partial pressure (P_CO2) in the atmoshpere (the chemical exchange). A second mechanism involves the organic fixation of inorganic dissolved carbon by hpytoplankton through the process of photosynthesis and the export of new primary production to sediments or abyssal water (the biological exchange). This exchange may be enhanced by antropogenic autrophication of coastal seas. The third mechanism involves the sinking of cold surface waters equilibrated to the recent high P_CO2 in polar regions (the physical exchange). Both the chemical and the biological exchanges can operate in coastal seas as well as in the open ocean. An important question to address is whether coastal seas, which constitute about 7,6% of the surface area of the world ocean, are a net source or sink of atmospheric CO₂ .

At present, the question of whether coastal seas are net sinks or sources of atmospheric CO₂ , cannot be answered. Like all other natural systems, coasts seas are governed by numerous physical, chemical, biological and geological processes which respond to external change on various spatial and temporal scales. Therefore, a certain region of the coastal sea may be a sink for CO₂ under some conditions (for example during the daytime, summer months,anthropogenic era, etc.) but not under others (for example during the night-time, winter months, undisturbed conditions,etc.). Similarly,a particular coastal sea may be subjected to anthropogenic impacts such as enhanced inputs of nutrients, altering its capacity as a source of sink of carbon. (Kempe, 1995.)

It is therefore necessary to investigate the role of the coastal seas in the global carbon cycle more thoroughly if we want to know what happens regionally and on anthropogenically relevant time scales. This is reflected in the reasearch recommended in the LOICZ Implementation Plan (Pernetta and Milliman, 1995.).

Figure 2.   - Schematic presentation of the exchanges involved in CO₂ by the coastal sea (Kempe, 1995.)

REFERENCES

- Stumm W. and Morgan J.J. (1970) - Aquatic Chemistry, p.p. 338-342.

Wiley-Interscience, New York.

-Kempe S. (1995) - Coastal Seas: a net source or sink of atmospheric carbon dioxide. Loicz reports and Studies No I.,p.p. 1-3, Den Burg - Texel.

-Pernetta J. and J.Milliman,1995. Land-Ocean Interactions in the Coastal Zone: Implementation Plan. IGBP Report No. 33., IGBP, Stockholm, Sweden, 215 pp.

PROPOSITION FOR EXPERIMENTAL RESEARCH IN SITU MONITORING:

Gulf of Kotor in southern part of Adriatic coast.

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