The
intertidal zones of Bermuda are a beautiful
site to see. The marine snails that inhabit them are exposed to extreme desiccation
in times of low rain fall. Two species, found in close proximity to each
other, have different tolerances for desiccation. Cenchritis muricatus (Beaded Periwinkle) can survive days or weeks
with out water. Another species, Batillaria
minima, can only survive days [Lang
et. Al, 1998]. Because of the vitality of water do these organisms
seize every opportunity to acquire it? Do events such as high rainfall or
flooding provide the same relief has storms and high tides? The purpose of
this study was to determine if intertidal snails utilized each source of water
in their environment, salt and fresh. I collected these two species, , from a large tide pool at
Spittal Pond, Bermuda. I
collected eight individual C. muricatus
and 52 B. minima. All individuals were dried, if not already
dry. I used tide pool water and filtered rain water as the two treatments.
In lined petri dishes I subjected the samples to fresh water and then salt water,
in separate dishes. The reactions and behaviors of the snails were recorded
using notes, pictures and video clips. I observed each treatment for at least 15
minutes. In both species the results were the same. There
was no movement from the samples when exposed to freshwater. Almost all
individuals moved when exposed to salt water. A chi2 test yielded a p-value of 0.0004 (C. muricatus) and 0.0000
(B. minima) when I compared movement
to treatment. C. muricatus and B. minima are well adapted to
there environment. Based on the results of this experiment these gastropods do
not respond to freshwater.