Pacific Science Volume 45, Number 4, 1991

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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.

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    45: Index - Pacific Science
    (University of Hawai'i Press, 1991)
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    45:4 Table of Contents - Pacific Science
    (University of Hawai'i Press, 1991-10)
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    A Temporal Sequence (Chronosequence) of Soil Carbon and Nitrogen Development after Phosphate Mining on Nauru Island
    (University of Hawai'i Press, 1991-10) Manner, Harley ; Morrison, R.J.
    Ten composite soil samples (0-15 cm depth) were collected from abandoned phosphate-mined sites on Nauru Island (Central Pacific) and analyzed for % organic C and % N. The samples represent a temporal sequence (chronosequence) of soil development spanning < 55 yr. The increase of% C and % N was fairly rapid. In recently mined sites « 1 yr) the values of % C were between 0.41 and 0.48, and those for % N were between 0.03 and 0.04. Fifty-five years after mining, the values of % C and % N were 4.56 and 0.33, respectively, and comparable to the amounts found in undisturbed Lithic Haplustolls, Typic Haplustolls, and Lithic Ustorthents epipedons. These changes in soil properties are considered to be a function of time and the accompanying seral development of vegetation (particularly the fern cover of Nephrolepis biserrata and Polypodium scolopendria) , because parent materials, climate, and other factors of soil formation are considered to be constant. Rate of soil development is faster in the unconsolidated sands and limestone rubble of the pit bottoms and slower on the dolomitic limestone pinnacle surfaces.
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    Natural Interspecific Hybridization in Gunnera (Gunneraceae) of the Juan Fernandez Islands, Chile
    (University of Hawai'i Press, 1991-10) Pacheco, Patricia ; Stuessy, Tod F. ; Crawford, Daniel J.
    Natural interspecific hybridization between Gunnera bracteata and G. peltata (Gunneraceae) in the Juan Fernandez Islands, Chile, is analyzed morphologically and chemically. Parental types from isolated populations were compared with parents and intermediates occurring together in Quebrada Villagra on Masatierra. Two transects were made in that area, one in a relatively undisturbed site, and another along a disturbed path. Hybrid indexes and distance diagrams were used to analyze morphological relationships, and leafflavonoids revealed chemical affinities. Minor flavonoid divergence between parental species precluded detailed analysis of dynamics of hybridization. Morphological analysis revealed intermediacy in both transects,with intergradation back toward both parents. It is suggested that introgressive hybridization is occurring in Quebrada Villagra between these two wind-pollinated species, with more hybridization taking place in disturbed regions. Reduction in surface area and changes in the ecology of Masatierra during the past four million years may have brought the two species into closer contact and aided hybridization.
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    Cyclohelia lamellata, New Genus and Species of Stylasteridae (Cnidaria: Hydrozoa) from the Bering Sea
    (University of Hawai'i Press, 1991-10) Cairns, Stephen D.
    A new genus and species of Stylasteridae is described, Cyclohelia lamellata, based on one specimen from 550 m off the Pribilof Islands, Bering Sea. The species is unusual in having a lamellate growth form and unique in having elliptical dactylopore spines that are rimmed on all sides. The genus is hypothesized to be most closely related to Distichopora and Sporadopora. Cyclochelia lamellata is one of the most northerly records of a stylasterid in the Pacific Ocean.
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