[eng] In the current study the microbial diversity from the Cova des Pas de Vallgornera
located in the southeast coast of Mallorca was analyzed. The samples were taken in
“Galeria d’en Pau” situated in the center of the endokarstic system and about 2 km
from the entrance. Samples were taken from drip-water falling from speleothems, water
from gours and phreatic lakes in semi-submerged galleries. Microbial diversity was
evaluated by a metagenomic approach. Drip-water and gours showed lower diversity
and shared a major number of taxonomic units than the brackish waters. Moreover, the
binned Metagenome Assembled Genomes (MAGs) from the most abundant
populations allowed performing phylogenetic studies. From a total of 14 MAGs
recovered from drip-water and gours, the most abundant were associated to the
Acinetobacter genus, Sphingomonadaceae family and the class
Gammaproteobacteria. Members of the genus Acinetobacter represented 2 different
species, associated to bio-mineralization processes contributing to calcareous
structures formation. Additionally, related to Archaea domain, 5 MAGs recovered were
associated to the family Nitrososphaeraceae and Nitrosopumilaceae, whose
chemolithoauthotroph and ammonia-oxidizing metabolism could be linked to part of the
primary production in the cave. On the other hand, samples from phreatic lakes
showed higher diversity and it was possible to recover 27 MAGs. The most abundant
MAGs affiliated with the family Comamonadaceae and Nitrospiraceae. Additionally, 3
MAGs affiliated with the archaeal domain: i.e. Candidatus Nitrosoarchaeum,
Nitrososphaera and Thaumarchaeota archeon of the phylum Thaumarchaeota, also
indicating that in these systems the primary production can be associated by ammoniaoxidizing microorganisms as in the other samples.