Microbial Diversity and Activity of Biofilms from Geothermal Springs in Croatia

Kostešić, Ema; Mitrović, Maja; Kajan, Katarina; Marković, Tamara; Hausmann, Bela; Orlić, Sandi; Pjevac, Petra (2023) Microbial Diversity and Activity of Biofilms from Geothermal Springs in Croatia. Microbial Ecology, 86 (4). pp. 2305-2319. ISSN 0095-3628

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Abstract

Hot spring biofilms are stable, highly complex microbial structures. They form at dynamic redox and light gradients and are composed of microorganisms adapted to the extreme temperatures and fluctuating geochemical conditions of geothermal environments. In Croatia, a large number of poorly investigated geothermal springs host biofilm communities. Here, we investigated the microbial community composition of biofilms collected over several seasons at 12 geothermal springs and wells. We found biofilm microbial communities to be temporally stable and highly dominated by Cyanobacteria in all but one high-temperature sampling site (Bizovac well). Of the physiochemical parameters recorded, temperature had the strongest influence on biofilm microbial community composition. Besides Cyanobacteria, the biofilms were mainly inhabited by Chloroflexota, Gammaproteobacteria, and Bacteroidota. In a series of incubations with Cyanobacteria-dominated biofilms from Tuhelj spring and Chloroflexota- and Pseudomonadota-dominated biofilms from Bizovac well, we stimulated either chemoorganotrophic or chemolithotrophic community members, to determine the fraction of microorganisms dependent on organic carbon (in situ predominantly produced via photosynthesis) versus energy derived from geochemical redox gradients (here simulated by addition of thiosulfate). We found surprisingly similar levels of activity in response to all substrates in these two distinct biofilm communities, and observed microbial community composition and hot spring geochemistry to be poor predictors of microbial activity in the study systems.

Item Type:	Article
Uncontrolled Keywords:	Hot spring; Biofilm; 16S rRNA gene amplicon analysis; BONCAT; CARD-FISH
Subjects:	NATURAL SCIENCES > Geology NATURAL SCIENCES > Biology BIOTECHNICAL SCIENCES
Divisions:	Division of Materials Chemistry
Projects:	Project title Project leader Project code Project type Višefazni pristup za dešifriranje mikrobne ekologije i biotehnološkog potencijala geotermalnih izvora u Hrvatskoj-MAMEBio Sandi Orlić; Petra Pjevac; Marija Vuković Domanovac; Martina Sudar PZS-2019-02-7373 HRZZ
Depositing User:	Josipa Karadžole
Date Deposited:	15 Apr 2026 11:04
URI:	http://fulir.irb.hr/id/eprint/11718
DOI:	10.1007/s00248-023-02239-1

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