title: Evolution of microbial "streamer" growths in an acidic, metal-contaminated stream draining an abandoned underground copper mine.
abstract: A nine year study was carried out on the evolution of macroscopic "acid streamer" growths in acidic, metal-rich mine water from the point of construction of a new channel to drain an abandoned underground copper mine. The new channel became rapidly colonized by acidophilic bacteria: two species of autotrophic iron-oxidizers (Acidithiobacillus ferrivorans and "Ferrovum myxofaciens") and a heterotrophic iron-oxidizer (a novel genus/species with the proposed name "Acidithrix ferrooxidans"). The same bacteria dominated the acid streamer communities for the entire nine year period, with the autotrophic species accounting for ~80% of the micro-organisms in the streamer growths (as determined by terminal restriction enzyme fragment length polymorphism (T-RFLP) analysis). Biodiversity of the acid streamers became somewhat greater in time, and included species of heterotrophic acidophiles that reduce ferric iron (Acidiphilium, Acidobacterium, Acidocella and gammaproteobacterium WJ2) and other autotrophic iron-oxidizers (Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans). The diversity of archaea in the acid streamers was far more limited; relatively few clones were obtained, all of which were very distantly related to known species of euryarchaeotes. Some differences were apparent between the acid streamer community and planktonic-phase bacteria. This study has provided unique insights into the evolution of an extremophilic microbial community, and identified several novel species of acidophilic prokaryotes.
authors.affiliation: College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK. c.kay@bangor.ac.uk.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Kay
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden. owen.rowe@emg.umu.se.
authors.forename: Owen F
authors.initials: OF
authors.lastname: Rowe
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Rocchetti
authors.affiliation: College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK. kcoupland@hotmail.co.uk.
authors.forename: Kris
authors.initials: K
authors.lastname: Coupland
authors.affiliation: College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK. kevinhallberg@sky.com.
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Hallberg
authors.affiliation: College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK. d.b.johnson@bangor.ac.uk.
authors.forename: D Barrie
authors.initials: DB
authors.lastname: Johnson