Abstract

DONATO-RONDON, Jhon Ch.. Diversity of diatoms in an Andean fluvial system: nutrients and conductivity as explanation factors. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2019, vol.43, n.169, pp.728-736. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.939.

This study assessed the diversity and structure of the diatom communities using mature benthic algae communities that grew on artificial substrates for one month. Samples were collected for nine (9) months between October 2007 and January 2009 in a 50 m reach in the middle sector of the Tota River (Boyacá - Colombia) at an altitude of 2,540 m. Changes in the composition were evaluated using taxonomic determinations, as well as Shannon-Wiener [H '] and Simpson diversity indices [S]. These indices showed a significant correlation (p=<0.05) with phosphates (P-PO4 3-), nitrates (N-NO3-) and flow (L s-1) suggesting that these local factors not only shape diversity but also the structure of the diatoms in the reach. The redundancy analysis (RDA) showed that conductivity (28%), phosphates (27.5%), flow rate (11.4%), and nitrates (8.0%) contributed to the variance. Melosira varians, Navicula rynchocephala, and Navicula capitatoradiata were associated with high phosphate concentrations, while Achnanthidium minutissimum and Nitzschia sp2 with low phosphates. Eunotia minor, Nitzschia sp1, and Reimeria sinuata were associated with high nitrates and caudal, and Epithemia sorex and Gomphonema parvulum, with high conductivity waters and low caudal. The Andean rivers are immersed in a network of diverse environmental and physical patterns and, in such context, the knowledge of biodiversity is the basis for the environmental management of the basins and the elaboration of regional management plans for the conservation of biodiversity.

Keywords : Colombia; Andes; benthic algae; stream; phosphates; nitrates; Tota.

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