EFFECTS OF WATER VELOCITY ON THE ARCHITECTURE AND EPIPHYTES OF CLADOPHORA GLOMERATA (CHLOROPHYTA)1

Authors

  • Elizabeth A. Bergey,

    Corresponding author
    1. Department of Fisheries and Wildlife, Utah State University, Logan, Utah 84322, and Department of Entomological Sciences, University of California, Berkeley, California 94720
      Address for reprint requests: Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706.
    Search for more papers by this author
  • Charlotte A. Boettiger,

    1. Department of Entomological Sciences, University of California, Berkeley, California 94720
    Search for more papers by this author
  • Vincent H. Resh

    1. Department of Entomological Sciences, University of California, Berkeley, California 94720
    Search for more papers by this author

  • 1

    Received 10 August 1994. Accepted 12 January 1995.

Address for reprint requests: Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706.

ABSTRACT

The architecture of the filamentous green alga Cladophora glomerata (L.) Kütz. and the composition of this alga's epiphytes [primarily the diatoms Epithemia turgida (Ehrenb.) Kütz., Epithemia sorex Kütz., and Cocconeis pediculus Ehrenb.] were examined in different velocity regimes. After transferring algal-bearing cobbles among velocities, the effects of changes in velocity were also examined. Cladophora branching pattern did not initially differ among slow, medium, and fast velocities, indicating that stable water velocities did not affect branching pattern. Two weeks after cobble transfer, Cladophora in fast velocity had fragmented more (i.e. had fewer filaments and fewer branch points per length of filament and had a higher percentage of unbranched filaments) than Cladophora in slow velocity. Fragmentation was greatest in tufts moved from slow velocity, suggesting velocity-associated differences in susceptibility to breakage. Epiphytic assemblage composition differed among slow, medium, and fast velocities and between locations on the filament (base and apex). Cocconeis pediculus dominated where exposure to high velocity was greater (filament apices in medium and fast velocities), whereas the Epithemia spp. dominated where lower velocities occurred (filament bases in all velocities and apices in slow velocity). Two weeks after the cobble transfer, the translocated diatom assemblages had changed and the original pattern of diatom distribution was restored.

Ancillary