Factors Affecting Epithecal Growth Lines in Four Coral Species, with Paleontological Implications

<p>The number of epithecal (external) growth lines was surveyed over 124 days for Montastrea annularis growing at different depths (3.5 m to 61 m). There was a significant (P< .01) decrease in the number of lines with depth. Although the linear regression is significant, there is evidence for a logarithmic or quadratic relationship, and more data from greater depths are needed to determine which of these gives a better fit.</p> <p>The number of growth lines formed during light-dark cycles of 16, 24 and 32 hours were compared for M. annularis, M. cavernosa, Porites astreoides and Tubastrea aurea. The variability among colonies from the same species was in many cases more significant than that among light treatments. This is a serious problem for anyone counting lines in corals, especially from a few specimens; therefore conclusions based on such counts seem hazardous on fossil corals for which the environmental factors are unknown.</p> <p>For M. annularis, the number of lines increased with the frequency of the light cycle.</p> <p>When tested under bright and dim light conditions, linear growth was depended on the amount of light, but unaffected by light-dark periodicity. Results for the other species were not conclusive, possibly due to smaller sample size.</p> <p>Opening and closing of the polyps was related to the light vs. dark phase of the light cycle, but appeared unaffected by a change in length of the cycle.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year

1986

Author dc:creator

• Liénard, Jean-Luc

Contributors dc:contributor

• Ariel A. Roth
• Leonard R. Bullas
• Conrad D. Clausen
• Elwood S. McCluskey
• Paul Y. Yahiku

• Biology
• Geology
• Corals -- Growth; Corals; Fossil; Geological time

Statement dc:rights

• This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/1080

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-1594