Periphyton on artificial substrata from three lakes of different trophic status at Hope Bay (Antarctica)

PIZARRO, H; A. VINOCUR; TELL, G.

POLAR BIOLOGY

SPRINGER

Año: 2002 vol. 25 p. 159 - 169

0722-4060

SUMMARY The nutrient contents of aquatic environments at Hope Bay (Antarctica) depends on different factors, penguin acclivities being one of the most important. In this study we surveyed three water bodies of different morphometry and trophic status: Esperanza  lake (oligotrophic), Boeckella lake (meso-eutrophic), and Pingüi pond (hypereutrophic). This research provides a preliminary characterization of the periphyton colonization on artificial substrata (glass slides) of these water bodies from the end of January to mid March 2000. Qualitative and quantitative analyses of the algae, biomass determinations (chlorophyll a, DW and AFDW), and physical and chemical variables of the lakes were assessed. The Autotrophic Index and the Lakatos system of classification were also applied. All three lakes differed clearly in all the variables considered. The periphyton from Esperanza Lake was first dominated by Bacillariophyceae (Fragilaria ulna), and subsequently by the Chrysophyceae Phaeogloea mucosa. P. mucosa was the dominant species at Boeckella Lake and Chlamydomonas subcaudata was dominant at Pingüi pond. Highest mean maximum density values were reached at Pingüi Pond (1,898,790 ind. cm-2, followed by Boeckella (465,729 ind. cm-2) and Esperanza (305,784 ind. cm-2) lakes. Highest biomass figures were registered with increasing trophic status (in Esperanza lake: mean maxima of 0.17 mg chl. a cm-2, 0.037 mg DW cm-2 and 0.029 mg AFDW cm-2; in Boeckella lake: 0.71 mg chl. a  cm-2 ; 0.42 mg DW cm-2 ; 0.072 mg AFDW cm-2  and in Pingüi Pond: 3.04 mg chl. a cm-2 ; 1.51 mg DW cm-2 ; 0.93 mg AFDW cm-2). According to the Lakatos? index, the periphyton of Esperanza Lake was the least developed and it was mainly organic and heterotrophic;  Boeckella Lake showed intermediate development in periphyton mass, autotrophic and mainly inorganic whereas Pingüi pond showed the highest development in periphytic mass, mainly autotrophic.