Effects of ambient flow and injury on the morphology of a fluid transport system in a bryozoan.
Many organisms use fluid transport systems that are open to the external environment for suspension feeding or gas exchange. How do factors related to the environment, such as injuries and ambient currents, affect remodeling of these systems? In the bryozoan Membranipora membranacea, the lophophores (crowns of ciliated tentacles) form a canopy over the colony. The lophophores pump seawater from above the colony through themselves to capture food particles. The seawater then flows under the canopy to exit the colony at chimneys (openings in the canopy) or at the canopy edge. To test whether either ambient flow speed or injury affects remodeling of this system, I measured changes in chimney size and spacing in colonies grown in flow tanks at different ambient flow speeds, and in colonies in which I killed patches of zooids. There was no effect of either ambient flow speed or injury size on chimney remodeling. Injury did not induce chimney formation. In addition, chimneys formed at the canopy edge, indicating that high pressure under the canopy did not induce chimney formation. These results suggest that ambient flow, injury, and the pressure under the canopy may have little effect on the remodeling of this fluid transport system.
von Dassow
Michelangelo
M
Integrative Biology Department, 3060 VLSB #3140, Berkeley, California 94720-3140, USA. mvondass@socrates.berkeley.edu
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002013:Bryozoa / Q000033:anatomy & histology* / Q000502:physiology*; D014743:Videotape Recording