Blue-Green Algal Mats from Acidified Adirondack Lakes: Mat Structure and pH Response of Algal Isolates

Abstract

Seven acidified lakes in the Adirondack mountains of New York, USA were sampled for benthic algae during the summer of 1982. Benthic cyanophyte mats, dominated by Schizothrix spp. were found in three of the seven lakes sampled (Big Moose, pH 4.00-4.40; Limekiln, pH 4.60-5.30; Wolf, pH 3.45-3.70). The blue-green algal mats found were structurally similar to living stromatolite analogs found in other extreme environments. Under controlled laboratory conditions, unialgal isolates of Schizothrix calcicola (Ag.) Gom., grew best at or near neutrality but could survive and grow slowly at low pH (4.0, 5.0). Increased nutrient levels appeared to have little effect on growth or survival in buffered low pH (4.0) media. Cultures of S.calcicola were able to raise the pH of unbuffered media three pH units in less than 72 hours. Clumping and aggregation of filaments was enhanced by lowering the pH (to pH 3.5 in 5.5 hours) of actively growing cultures.