Gradients of physical disturbance are central to
theories of community organization yet rarely are studies
performed in which physical factors are experimentally
manipulated. Pothole tidepool algal communities exhibit
distinct zonation patterns from top to bottom that result
from scouring by rocks and other debris in the pools.
Scouring is easily manipulated by removing or adding rocks
to tidepools. Thus, the gradient of physical disturbance
potentially causing community patterns can be manipulated
to test theories of community organization.
I documented the distribution pattern of algae
inhabiting pothole tidepools and measured a number of
physical factors which were hypothesized to be responsible
for the observed zonation patterns. Then, I experimentally
evaluated the roles of physical disturbance, herbivory, and
competition in these tidepool communities. I found that
scouring by rocks was primarily responsible for the
observed zonation patterns in pothole tidepools. However,
not all pools are potholes. Evaluation of the physical
properties effecting the cobble-retaining ability of
tidepools enabled prediction over a broad geographic range
of pools likely to have cobbles and thus show typical
pothole algal zonation patterns.
Coralline algae (Rhodophyta, Corallinaceae) are a
dominant feature of tidepools as well as many low
intertidal and subtidal habitats. I evaluated the relative
resistance of coralline algae (both articulated and
crustose forms) and other common tidepool algae to scouring
by rocks. Coralline crusts were highly resistant to
scouring while articulated coralline algae are very
susceptible to scouring. Erect fleshy algal species showed
intermediate resistance to scouring. This corresponds well
to observed algal zonation patterns in intertidal potholes.
Based on this information, I proposed that wave-induced
scouring may have been the selective force for the initial
incorporation of calcium carbonate into algal thalli. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36347 |
| Date | 17 March 1992 |
| Creators | van Tamelen, Peter G. |
| Contributors | Menge, Bruce A, |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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