PARTICLE TRANSPORT AND INCORPORATION DURING SKELETON FORMATION IN A KERATOSE SPONGE: DYSIDEA ETHERIA

¹ Department of Zoology, Duke University, Durham, North Carolina 27706

The mechanism and significance of sand particle incorporation into skeletal fibers were investigated in the sponge, Dysidea etheria. Time lapse cinemicrography of the sponge surface showed that this species actively transported particles at an average rate of 7.5 µm/min to areas where skeletal fibers were formed. Transport was associated with specific structures of the sponge's dermal membrane. Sand particles applied to sponge explants for five weeks increased skeletal fiber growth over growth in explants experiencing ambient particle loads. Explants deprived of particles had significantly less fiber growth. The location of applied particles influenced the direction of fiber growth. The results indicate that particles enhance skeletal fiber growth by acting as a filler material in the construction of fibers and may influence the overall direction of growth and shape of the skeleton.