Diversity of aerophytic cyanobacteria and algae in biofilm from selected caves in Serbia

Abstract

Predmet ove doktorste disertacije je analiza zajednice aerofitskih cijanobakterija i algi iz biofilma sa stenovitog supstrata ulaza petnaest odabranih pećina iz Srbije kao i nekoliko tačaka u blizini veštačkog osvetljenja. Akcenat istraživanja bio je na fototrofnim mikroorganizmima iz biofilma, dok su kao dodatak endolitski predstavnici identifikovani iz nekoliko uzoraka stene. Analizirana je i morfologija, stepen razvijenosti biofilma, kao i udeo sadržaja vode, organske i neorganske materije u biofilmu. U svim pećinama, mereni su ekološki parametri i određene su primarna produkcija (preko koncentracije hlorofila a) i petrografska analiza stenovitog supstrata. Na odabranim uzorcima rađena je kvantitativna i sezonska analiza cijanobakterija i algi. Statističke analize su poslužile kao alat za sagledavanje odnosa zabeleženih fototrofnih mikroorganizama i različitih ekoloških i opisnih parametara. Zabeleženo je prisustvo ukupno 290 taksona cijanobakterija i algi koje su svrstane u 4 razdela: Cyanobacteria (134 taksona, od kojih 82 taksona pripada kokoidnim formama), Bacillariophyta (129 taksona), Chlorophyta (26 taksona) i Xanthophyta (1 takson). Najveći broj taksona Cyanobacteria zabeležen je u rodovima Gloeocapsa, Chroococcus, Gloeothece, Leptolyngbya i Scytonema. U razdelu Bacillariophyta se izdvajaju rodovi Luticola i Humidophila, a u razdelu Chlorophyta rod Cosmarium. Iz biofilma Božanine pećine opisana je nova vrsta cijanobakterije za nauku, Nephrococcus serbicus S. Popović, G. Subakov Simić i J. Komárek, sp. nov. pri čemu je sam rod po prvi put zabeležen na teritoriji Evrope. Cyanobacteria po broju taksona dominiraju na svim lokalitetima, osim Rćanske i Bogovinske pećine. Najveći broj pripadnika Bacillariophyta i Chlorophyta zabeležen je u Rćanskoj (usled prisustva vode na biofilmu) i pećini Samar (zbog sezonskog uzorkovanja). Upravo se značaj sezonskog uzorkovanja biofilma u pećinama Samar i Jezava pre svega ogleda kroz znatno veći diverzitet aerofitskih cijanobakterija i algi u odnosu na druge pećine. Predstavnici Cyanobacteria dominirali su u pećinama čiji je supstrat rekristalisali i organogeni krečnjak, a Bacillariophyta na klastičnom i mikritskom krečnjaku...The aim of this PhD thesis is the analysis of the aerophytic cyanobacterial and algal community from biofilm developed on stone substrate at the entrance of fifteen selected caves from Serbia and several sites near the artificial light in caves. The focus of the study was on phototrophic microorganisms from the biofilm, while endolithic representatives were additionaly identified from several stone samples. Morphology, degree of biofilm development, as well as the content of water, organic and inorganic matter in biofilm were also observed. At all sampling sites, ecological parameters, primary production (through concentration of chlorophyll a), as well as petrographic analysis of rocky substrates were measured and determined. Quantitative and seasonal analyzes of cyanobacteria and algae were assessed in selected samples. Statistical analyzes have served as a tool for examining the relationship between recorded phototrophic microorganisms and various ecological and descriptive parameters. A total of 290 cyanobacterial and algal taxa were recorded and classified into 4 divisions: Cyanobacteria (134 taxa, of which 82 taxa belong to the coccoid forms), Bacillariophyta (129 taxa), Chlorophyta (26 taxa) and Xanthophyta (1 taxon). The highest number of cyanobacterial taxa was documented within the following genera: Gloeocapsa, Chroococcus, Gloeothece, Leptolyngbya and Scytonema. Luticola and Humidophila were the most diverse genera within Bacillariophyta division, while in Chlorophyta Cosmarium had the highest number of species. A new cyanobacterial taxon, Nephrococcus serbicus S. Popović, G. Subakov Simić & J. Komárek, sp. nov., was described from a biofilm sample of Božana Cave. This also represents the first record of the genus Nephrococcus in Europe. Cyanobacteria were dominant in all caves, except Rćanska and Bogovinska cave. The largest number of Bacillariophyta and Chlorophyta was recorded in the Rćanska cave (due to the presence of water on samplins sites) and in the Samar Cave (due to seasonal sampling). The significance of the seasonal biofilm sampling in Samar and Jezava caves is primarily reflected through the higher diversity of aerophytic cyanobacteria and algae in comparison to other caves..