Naslov
Moonmilk in Postojna cave, Slovenia

Autori
Mandić, Magda ; Mihevc, Andrej ; Zubin Ferri, Tea ; Ćetković, Helena ; Pleše, Bruna ; Krajcar Bronić, Ines

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Karst and microorganisms / Mulec, Janez - Postojna : Karst Research Institute - ZRC SAZU, 2014, 38-38

ISBN
978-961-254-705-9

Skup
22nd International Karstological School "Classical Karst"

Mjesto i datum
Postojna, Slovenija, 16.06.2014. - 20.06.2014

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
moonmilk ; bacteria ; petrography ; SEM micrographs ; DNA sequencing

Sažetak
A comprehensive multidisciplinary study of Postojna Cave, the largest known cave in Europe and most visited cave in Slovenia, related to modern speleothem formation conditions that included one year monitoring of environmental conditions in the Cave and stable isotope analyses resulted in finding locations and samples which are promising candidates for paleoclimate investigations (Mandić, 2013). One of such samples is moonmilk from location Zgornji Tartar. Monitored environmental parameters of location microclimate and requirements for carbonate deposition under isotopic equilibrium on this location are fulfilled. Mean air temperature at location Zgornji Tartar is 10.7 ± 0.9 ºC and mean water temperature is 10.9 ± 1.0 ºC. Mean values of conductivity, pH, and pCO2 are 313 ± 123 µS/cm, 7.8 ± 0.3, and 937 ± 325 ppmv, respectively. Mean values of magnesium, calcium and bicarbonate concentrations are 0.8 ± 0.2 mg/L, 76 ± 4 mg/L, and 215 ± 24 mg/L, respectively. Because this is the first time that moonmilk is described in Postojna Cave, additional investigations helped its better characterization. Petrographicaly, the moonmilk is composed of calcite needles approximately 100 µm long, and 10 µm wide. SEM micrographs of moonmilk show evidence of microbial biomediation or bioprecipitation Also used Fourier transform infrared (FTIR) analysis indicate presence of organic compounds. Since Postojna Cave is touristic cave the question arose whether the organic compounds found in moonmilk sample are results of native cave microorganisms or if they are allochthonous species. Therefore, bacterial isolate DNA sequences were analyzed using BLAST, which identified sequence homologies with previously identified isolates. Sequences showing greater than 97% identity across the amplified region were considered to belong to the same operational taxonomic unit (OTU). Most of the sequences (68.4 %) were affiliated with the phylum Actinobacteria (species Streptomycetes). Uncultured bacteria from environmental samples were presented with 11.6% followed by Proteobacteria (1%) showing the highest identity with Klebsiella sp. thus indicating that microorganisms in moonmilk at the studied location are native. Mandić M., 2013. Determination of equilibrium conditions of carbonate precipitation in Postojna Cave with possible application to paleoclimatology. Ph.D. Thesis, Zagreb, University of Zagreb, 205 p.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Geologija, Biologija

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