SMAW, SHERCODA*, LAFAYETTE FREDERICK, and RAYMOND L. PETERSEN. Biology Department, Howard University, Washington, DC 20059. - The urban moss Bryum capillare Hedw.: cyanobacterial and agal assoicates as biogenic crusts.
Bryum capillare Hedw. is a cosmopolitan moss ubiquitous in
cities, where it occurs as a dense-green velvet growths between the
cracks in sidewalks. We report on the cyanobacterial and algal
associates of B. capillare and the role they have in building
biogenic crusts. Individual plantlets of B. capillare are
cultured on 1/5 strength Hoagland’s 1% agar medium. After five days a
variety of cyanobacteria and algae are observed growing out from B.
capillare implants. Some of the more abundant cyanobacterial taxa
observed are: Lyngbya sp., Calothrix sp.,
Osillatoria sp. Phormidium sp., Hyrocoleum
homeotrichum, Anabaena sp. Anabeana circinalis,
Synechocysitis aquatilis, Shizothrix sp. Among the
eukaryotic algae present are: Klebsomium sp. Ulothrix
sp. and an unidentified diatom. Most of these cyanobacteria and algae
are filamentous. This morphology probably adds a textile-like
resiliency to the biogenic crust. Based on these observations it is
hypothesized that the laying down of a cyanobacterial/algal mat is a
prerequisite for B. capillare colony growth. This suggestion is
supported by the field observation of a biogenic crust of
cyanobacteria and algae subtending B. capillare colonies. This
study is ongoing and should have applications to moss ecology and
processes of primary succession.
Key words: algae, biodiversity, biogenic crusts, Bryum capillare, cyanobacteria, primary succession