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The Effects of Ultraviolet Radiation on Reef Corals and the Sun-Screening Role of Mycosporine-like Amino Acids

Shallow-dwelling scleractinian corals live in high irradiance environments where
they are exposed to large fluxes of ultraviolet radiation (UVR, 280 - 400 nm). A suite of
UV-aborbing compounds, know as mycosporine-like amino acids, is found within the
tissues of coral-algal symbioses and may perform a sun-screening role. The seasonal
variation in MAA concentration was investigated for two corals in Kaneohe Bay,
Hawai'i, Porites compressa and Montipora verrucosa. Regressions of MAA
concentration and the amount of UVR measured prior to collection date were not
significant for total MAA concentration of either species. However, individual MAAs,
shinorine in P. compressa and palythene in M. verrucosa, did show significant
correlation with UVR.
The effects of UVR and water motion on Porites compressa were investigated in
a flume and in the field. Exposure to ambient UVR was the most important factor tested
in determining the concentration of MAAs in the tissues of P. compressa. Water motion
also positively affected the concentration of MAAs, but only in the presence of UVR.
When UVR was screened from the corals' environment, the tissue concentration of
MAAs slowly decreased over time (approximately 2.5 to 5% per week) regardless of
water motion.
The effect of UVR on coral planulae was investigated in field experiments with
Pocillopora damicornis. Larvae were taken from four different source adults: those from
<0.5 m, those from 3 m, those incubated in the absence of UVR for two months, and
those incubated in ambient UVR for two months. Deep larvae and larvae from adults incubated in the absence of UVR had roughly half the amount ofMAAs found in the
shallow larvae and the larvae from adults in ambient UVR. Origin of larvae was not a
significant factor in determining larval survival or recruitment success. UVR, however,
was important in determining recruitment rate. Larvae were less likely to recruit to the
settlement tile in the presence of ambient UVR than in treatments where the UVR was
screened out. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1999.
Includes bibliographical references (leaves 151-164).

Identiferoai:union.ndltd.org:UHAWAII/oai:scholarspace.manoa.hawaii.edu:10125/15319
Date01 December 1999
CreatorsKuffner, Ilsa Boysen
PublisherUniversity of Hawai'i, Honolulu
Source SetsUniversity of Hawaii at Manoa Libraries
Languageen-US
Detected LanguageEnglish
TypeThesis, Text
Format175 pages
RightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.

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