LIFE TRSCA: Visit of Chinese researchers of karst ecosystems on the Cerkniško polje

Figure 1: Field observations of water properties at the spring of Martinjščica river (Photo: M. Blatnik).

A large part of the research within the LIFE Tršca project is dedicated to aquatic ecosystems, which include both research of water characteristics and aquatic vegetation. This is also one of the main research topics of Chinese researchers from Guilin (Institute of Karst Geology CAGS) and Wuhan (Institute of Hydrobiology CAS), who visited the Karst Research Institute ZRC SAZU and the Department of Biology of the Biotechnical Faculty of the University of Ljubljana between 16^th and 24^th November 2024. Besides several meetings where we presented our main research to each other, we carried out several field trips, where we also dedicated a whole day to the Cerkniško polje.

We have been actively cooperating with the Institute of Karst Geology CAGS (Chinese Academy of Geological Sciences) in Guilin for over 40 years. At first, the cooperation was informal through mutual visits, but later this also turned into project cooperation (UNESCO / IUGS IGCP, MOST and bilateral projects). The projects were usually related to the study of the karst surface (geomorphology and geology), the characteristics of hydrological dynamics (water quantity and quality), cave climate and karst soils. We also pay attention to the comparison between karst areas with different climatic conditions – Slovenia has a temperate climate, whereas Guilin has subtropical). We have not yet had active cooperation with the Institute for Hydrobiology CAS (Institute for Hydrobiology Chinese Academy of Sciences), but there are new ideas emerging, focused on joint study of karst ecosystems, especially biodiversity in karst waters and the dynamics of nutrients in water. On November 20, we organized a visit to the Department of Biology of the Biotechnical Faculty of the University of Ljubljana, where we shared information on our previous experiences in the research of karst ecosystems. We also visited the laboratory with the equipment for field sampling of macrophytes and following analyses of samples in the laboratory.

Figure 2: Meeting at the Department of Biology, Biotechnical Faculty UL (Photo: M. Blatnik).

Fieldwork was carried out between 16^th and 24^th November in various parts of Slovenia, covering the Alpine and Dinaric Karst. We spent most of our time in the catchment area of the Ljubljanica river, i.e. in the Pivska basin, Cerkniško polje, as well as downstream located areas such as Rakov Škocjan, Planinsko polje and the springs of the Ljubljanica river. We were especially focused on karst springs, which were the main interest to both groups from China. The group from Guilin (Institute of Karst Geology) carried out hand measurements of water characteristics of springs using a multiparameter probe. The main observed parameters were water temperature, specific electrical conductivity, reaction / pH and oxygen saturation. Additionally, field measurements of alkalinity and carbonate content were performed and several samples for further laboratory analyses were taken. Such observations were already made several times in the past and will be also in the future with the main idea to analyse the regional and temporal changes of the water parameter in different climatic settings and in different hydrological situations. A group from Wuhan (Hydrobiological Institute) checked whether macrophytes occur in the springs and which are the most characteristic species. It turned out that some are the same, while others are completely different species, but with similar physiological adaptations to those in China.

Figure 3: Visit of the laboratory at the Department of Biology, Biotechnical Faculty UL (Photo: M. Blatnik).

For the hydrobiological group from Wuhan, the first impression of the Slovenian karst was very positive, and the winter conditions during the fieldwork made it even greater. We hope that we will successfully apply for more joint projects that would complement the existing research on the Cerkniško polje, maybe already during the ongoing LIFE Tršca project.

Figure 4: Sampling of macrophytes at the Dolenje Jezero hydrological station (Photo: M. Blatnik).

Figure 5: Sampling of macrophytes at the Žerovniščica spring (Photo: M. Blatnik).

Figure 6: Field observations of water properties at the entrance of the Velika Karlovica cave (Photo: M. Blatnik).

Article was prepared by the Karst Research Institute and the Biotechnical Faculty of University of Ljubljana.