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N iphargus – T hiothrix associations may be widespread in sulphidic groundwater ecosystems: evidence from southeastern R omania
Author(s) -
Flot JeanFrançois,
Bauermeister Jan,
Brad Traian,
HillebrandVoiculescu Alexandra,
Sarbu Serban M.,
Dattagupta Sharmishtha
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12461
Subject(s) - biology , cave , ecology , ecosystem , clade , habitat , zoology , phylogenetics , biochemistry , gene
Niphargus is a speciose amphipod genus found in groundwater habitats across E urope. Three N iphargus species living in the sulphidic Frasassi caves in Italy harbour sulphur‐oxidizing T hiothrix bacterial ectosymbionts. These three species are distantly related, implying that the ability to form ectosymbioses with T hiothrix may be common among N iphargus . Therefore, N iphargus – T hiothrix associations may also be found in sulphidic aquifers other than Frasassi. In this study, we examined this possibility by analysing niphargids of the genera N iphargus and P ontoniphargus collected from the partly sulphidic aquifers of the Southern Dobrogea region of R omania, which are accessible through springs, wells and Movile Cave. Molecular and morphological analyses revealed seven niphargid species in this region. Five of these species occurred occasionally or exclusively in sulphidic locations, whereas the remaining two were restricted to nonsulphidic areas. T hiothrix were detected by PCR on all seven Dobrogean niphargid species and observed using microscopy to be predominantly attached to their hosts' appendages. 16S rRNA gene sequences of the T hiothrix epibionts fell into two main clades, one of which (herein named T4) occurred solely on niphargids collected in sulphidic locations. The other T hiothrix clade was present on niphargids from both sulphidic and nonsulphidic areas and indistinguishable from the T3 ectosymbiont clade previously identified on Frasassi‐dwelling N iphargus . Although niphargids from Frasassi and Southern Dobrogea are not closely related, the patterns of their association with T hiothrix are remarkably alike. The finding of similar N iphargus – T hiothrix associations in aquifers located 1200 km apart suggests that they may be widespread in E uropean groundwater ecosystems.