Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Systematic and Applied Microbiology 30 (2007): 531-546, doi:10.1016/j.syapm.2007.05.003.
Description:
The eukaryotic community of Río Tinto (SW, Spain) was surveyed fall, winter,
and spring through the combined use of traditional microscopy and molecular
approaches including Denaturing Gradient Gel Electrophoresis (DGGE) and sequence
analysis of 18S rRNA gene fragments. We compared eukaryotic assemblages of surface
sediment biofilms collected in January, May and September 2002 from 13 sampling
stations along the river. Physicochemical data revealed extremely acidic conditions (pH
ranged from 0.9 to 2.5) with high concentrations of heavy metals including up to 20 g l-1
Fe, 317 mg l-1 Zn, 47 mg l-1 As, 42 mg l-1 Cd, and 4 mg l-1 Ni. In total, 20 taxa were
identified, including members of the Bacillariophyta, Chlorophyta, and Euglenophyta
phyla as well as ciliates, cercomonads, amoebae, stramenopiles, fungi, heliozoan and
rotifers. In general, total cell abundances were highest in fall and spring decreasing
drastically in winter and the sampling stations with the most extreme conditions showed
the lowest number of cells as well as the lowest diversity. Species diversity does not
vary much during the year. Only the filamentous algae showed a dramatic seasonal
change almost disappearing in winter and reaching the highest biomass during the
summer. PCA showed a high inverse correlation between pH and most of the heavy
metals analyzed as well as Dunaliella sp., while Chlamydomonas sp. is directly related
to pH during May and September. Three heavy metals (Zn, Cu and Ni) remained
separate from the rest and showed an inverse correlation with most of the species
analyzed except for Dunaliella sp.
Description:
A.A was supported by the Spanish Ministry of Education and Science through the
Ramón y Cajal program. This work has been supported by grant CGL2005-05470/BOS
and grants to the Centro de Astrobiología at the Instituto National de Técnica
Aeroespacial.
Keywords:
Acidophilic organisms
;
Protists
;
Acidic environment
;
pH
;
Phytobenthos
;
Water chemistry
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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