Sediment as a Cause of MACROCYSIS Gametophyte Non-Survival

Survival of Macrocystis spp. gametophytes is a function of sediment depth on the surface to which they attach. Relative survival varies as an exponential function of calculated mean depth in all cases. If spores attach to a surface prior to sediment settlement, no survival is noted after four days at depths above 500 microns. If spore inoculation occurs after settlement, no survival is noted for calculated mean depths above 40 microns. Microscopic examination of silt dispersal patterns showed that below 40 micron depths the percentage of non-occluded surface was also an inverse exponential function of mean sediment depth. We infer that motile zoospores cannot pass through even the finest silt particles. Comparatively better survival is noted with attachment prior to deposition.