A PRELIMINARY ACCOUNT OF ENDOLITHIC ALGAE OF LIMESTONE CLIFFS OF THE NIAGARA ESCARPMENT

This paper reports the discovery of endolithic algae from vertical lim estone cliffs associated with the Niagara Escarpment, southern Ontario , Canada. The endolithic habitat forms a distinctive dark green layer 1-3 mm below the surface of the porous dolomitic limestone. Samples of the algal layer were isolated from freshly cleaved rock samples using sterile probes and grown on a solid (agarized) standard algal mineral medium supplemented with soil extract. A diverse assemblage of organi sms grew on the agar plates, including bacteria, fungi, blue-green alg ae (cyanobacteria), green algae, yellow-green algae, and occasionally the protonemata of mosses. Isolated algae belong to unicellular, colon ial, and filamentous morphological types. Algal genera that have been identified include seven blue-green algae (Cyanophyta or Cyanobacteria ), six green algae (Chlorophyta), and one yellow-green alga (Xanthophy ceae). Six of the algal genera found in Ontario rocks also occur insid e rocks of the Colorado plateau in northern Arizona, and one genus als o occurs inside Antarctic rocks.