Epilithic algae in a glacial stream at Hope Bay (Antarctica)

• Main Authors: Izaguirre, Irina, Pizarro, Haydee Norma
• Language: unknown
• Published: 1998
• Subjects: algae; community composition; cyanobacteria; epilithic algae; glacial stream; meltwater; Antarctica; Hope Bay; Chrysophyceae; Hydrurus foetidus; Phaeogloea mucosa; Phormidium fragile; Prasiola crispa; Antarctic; Argentina; Antarc*
• Online Access: https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07224060_v19_n1_p24_Izaguirre; https://hdl.handle.net/20.500.12110/paper_07224060_v19_n1_p24_Izaguirre

The epilithic algal community of a glacial stream of Hope Bay (Antarctica) was studied during the summer period of 1995. Major hydrological changes, which affected the main physical and chemical features, were observed in the stream according to the meltwater pulses. The enrichment of the stream by seabird inputs was evident from the high nutrient concentrations and their increase downstream. The presence of a snowbank in the middle reach produced a major discontinuity, influencing the main variables analyzed. The stream showed a similar algal composition to other water courses of Hope Bay, with Prasiola crispa, Hydrurus foetidus, Phaeogloea mucosa and Phormidium fragile as the dominant species. Chlorophyll a concentrations taken from natural substrata (stones) ranged from undetectable to 48.4 mg m-2, with the maximum concentrations associated with algal mats dominated by Prasiola crispa. with signs of enrichment by seabirds, and Prasiola crispa as one of the dominant algal species. Other similarities with either continental or maritime Antarctic streams include the presence of filamentous cyanobacteria (Hirano 1979; Broady 1982; Howard-Williams et al. 1986; Hawes 1989; Hawes and Brazier 1991). Nevertheless, the stream also showed the occurrence of an unusual flora of Chrysophyceae, very abundant in some reaches. Later studies carried out in other streams of Hope Bay have revealed a similar algal composition (Pizarro and Vinocur, in press). In the present study the epilithic algal community of one of the most important glacial streams of Hope Bay is described. Some of the most important physical and chemical variables regulating algal growth are discussed. Fil:Izaguirre, I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Pizarro, H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.