Year: 2010
Type: article
Abstract: Encounters with greater bacteria PRELUDE C roatia is today proud of its National Parks, which cover about 7.5 % of its territory.They are today superb tourist attractions and economic assets.That development was not always understood or appreciated.Within the economic recovery following World War 2 in what was then Yugoslavia, the options to preserve carbonate depositing waterfall of the river Krka in Dalmatia (today a National Park), or use them for energy generation, were seriously and vigorously debated and -the conservationists lost.It was then clear how little was known about the processes of carbonate dissolution and precipitation in the karstic region, or globally as a part of the carbon cycle.A modest research program was subsequently organized by Vale Vouk, professor at the University of Zagreb and member of the Yugoslav Academy of Sciences and Arts, to study this unique phenomenon and, as students, we had a chance to participate.The project to elevate the travertine barrier at Skradinski Buk and increase the capacity of the reservoir lake behind it for hydroelectric exploitation was later abandoned, probably after realization about the hidden hazards because of the porous and cavernous nature of the travertine deposit.The organisms that most prominently contributed and modified carbonate deposition, which made the Krka River famous were the aquatic mosses as it has been documented earlier for the Plitvice lakes and waterfalls (also a National Park and a UNESCO-registered World Heritage site of Croatia) (1).However, the detailed work has been performed by microorganisms associated with mosses but invisible to the plain eye.Each of the aquatic mosses, Cratoneuron (Palustriella) commutatum, Didymodon tophaceus, Cynclidotus aquaticus was covered by cyanobacteria (2) and microscopic algae, especially stalked diatoms and an unusual desmid Oocardium stratum (3, 4).Many of these microorganisms contributed to the process of carbonate deposition in specific ways and left imprints on the precipitate that has formed (5).However, under the most severe environmental conditions, in places under the impact of falling water, on sites of maximum carbonate precipitation or in the shade of the surrounding caves, the dominant microorganisms were always cyanobacteria (then called blue-green algae, cyanophyceae, myxophyceae or schizophyceae).This was my first encounter with blue-green algae that were not really algae and often not blue--green either.They were then considered a primitive group of phototrophic microorganisms marginal to cryptogamic botanists and completely ignored by bacteriologists, although their kinship to bacteria has been noticed brilliantly by Ferdinand Cohn more than hundred years earlier (6, 7).
Author: Stjepko Golubić
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W1584480506