Abstract
Corals from the western and equatorial Pacific Ocean have been
extensively studied for the purposes of generating paleoclimate
reconstructions spanning the last several hundred years. However,
in the central subtropical North Pacific, there are currently few
published coral records extending beyond 10 to 20 years. The
hermatypic coral species Porites lobata and Porites lutea have
proven to be useful indicators of paleoclimate and past sea
surface conditions at other locations. Here I have analyzed two
Porites lobata coral cores collected from colonies from opposite
sides of Oahu, Hawaii to assess their utility for developing
multi-decadal length climatic reconstructions in this region.
The two coral records are from Punalu'u Beach (157.881607°W,
21.576752°N) and Waikiki Beach (157.881607° W, 21.576752° N) and
presented here are isotopic (δ18O and δ13C) and trace metal data
(Sr/Ca, Pb, and other metals) from these two corals. An absolute
increase in sea surface temperatures of 1°C over the last 40 years
is clear in the instrumental SST data, along with a clear bias
towards the times of maximum SST during a negative phase of the
Pacific Decadal Oscillation (PDO). Lead (Pb) concentration for one
of the corals also coincides with the change in the PDO seen in
1976, with Pb concentrations decreasing from ~4-6ppm to between
0.5-1ppm. However, I infer this decline in concentration is more
probably due to the elimination of lead in gasoline. Other trace
metal data trends show increased concentrations of specific metals
during times of known Kona storm events. Presented here is the
longest sub-annual resolution paleoclimate record derived from
Hawaiian corals along with a comprehensive analysis of their
usefulness as a paleoclimate and environmental change indicator.
MacDonald, J., 2004. Stable isotopic and trace metal analyses of
two Porites Lobata colonies - Oahu, Hawaii: implications for past
seasonal variation and sea surface temperatures and anthropogenic
effects on the reef environment.
Unpublished MSc. thesis, State University of New York at Albany.
91 pp., +ii;
University at Albany Science Library call number: SCIENCE
Oversize (*) QC 869 Z899 2004 M33
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