Naslov
Microbial community structure in two anchialine caves on Mljet Island (Adriatic Sea)

Autori
Krstulović, Nada ; Šolić, Mladen ; Šantić, Danijela ; Maršić-Lučić, Jasna ; Ordulj, Marin ; Šestanović, Stefanija

Izvornik
Acta Adriatica (0001-5113) 54 (2013), 2; 183-198

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
anchialine caves ; cyanobacteria ; bacteria ; viruses ; heterotrophic nanoflagellates

Sažetak
The microbial abundances, including bacteria, viruses and heterotrophic nanoflagellates, were determined for two

Izvorni jezik
Engleski

Znanstvena područja
Biologija

Napomena
The microbial abundances, including bacteria, viruses and heterotrophic nanoflagellates (HNF), were determined for two anchialine caves located on the Island of Mljet (Adriatic Sea): Bjejajka Cave and Lenga Pit. Both caves are situated apprx. 100 m from the coast with extensive subterranean connections to the sea, resulting in noticeable marine and terrestrial influences. Because of the shallow settings of the studied caves, they represent habitats with a minimal light or complete darkness where photosynthesis is minimal or not possible. Thus, during the surveys there was no evidence of cyanobacterial cells in either caves, but the presence of bacteria, viruses and HNF was established. Further, bacterial abundance was higher in caves in comparison to surrounding open seawater. In the surrounding seawater the predominance of the LNA group over HNA is determined, whic also indicates the differences in relation to the studied caves. In fact, the dominance of HNA group of bacteria in caves, together with higher total bacterial abundance indicates that the caves are of higher trophic level than surrounding seawater. With regard to bacterial diversity, both caves had a unique makeup of bacterial populations and low diversity, with the chemolithoautotrophic Epsilonproteobacteria representing the most abundant taxonomic group. To examine the mechanisms regulating bacterial abundance in these habitats, we observed the relationship between bacteria and HNF, and between bacteria and viruses. The importance of predation in controlling bacteria (top-down control) and, consequently, the domination of bottom-up control of HNF were pbserved in both caves.

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