Pacific Science Volume 36, Number 2, 1982

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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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    36:2 Table of Contents - Pacific Science
    (University of Hawai'i Press, 1982-04)
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    Distribution, Morphology, and Geochemistry of Manganese Nodules from the Valivia 13/2 Area, Equatorial North Pacific
    (University of Hawai'i Press, 1982-04) Glasby, G.P. ; Friedrich, G. ; Thijssen, T. ; Pluger, W.L. ; Kunzendorf, H. ; Ghosh, A.K. ; Roonwal, G.S.
    Manganese nodules were collected during cruise 13/2 of R.V. Valdivia in 1976 in a small area of the equatorial north Pacific characterized by abyssal hill topography. The sediments are dominantly siliceous oozes in which extensive dissolution ofsiliceous material has taken place. Three principal nodule morphologies were recovered: polynucleate nodules, mononucleate nodules, and manganese crusts. Polynucleate nodules occur throughout the entire depth range studied whereas mononucleate nodules are found principally below 5000 m; manganese crusts are restricted to the abyssal hill environments. Nodule density remains on average roughly constant (> 7 kg/m2) with water depth (although varying considerably, 0-27 kg/m2, throughout the area), but the form in which the nodules occur changes with water depth. Nodule composition was investigated as a function of water depth, nodule size, and nodule morphology and shown to be related principally to nodule morphology. Mononucleate nodules have higher contents of Mn, Ni, Cu, and Zn and lower contents of Fe and Co than polynucleate nodules. The lithogenous fraction in the nodules is similar in both morphologies, although it varies considerably with nodule size. Both morphologies contain todorokite andJ-Mn02as the principal manganese oxide phases, but todorokite is relatively more abundant in the mononucleate nodules. The data are best interpreted in terms of the diagenetic supply of the transition elements Mn, Ni, Cu, and Zn to the nodules resulting from the in situ dissolution of siliceous tests in the sediment column. This process is more pronounced in the abyssal regions than on the flanks of the abyssal hills and leads to the enrichment of these elements in the larger mononucleate nodules embedded at the sediment -water interface there. This enhanced supply of transition elements also leads to the stabilization of todorokite in these nodules. Polynucleate nodules appear to be preferentially formed under conditions of higher sedimentation rate on the flanks of abyssal hills in an environment where abundant seeds are available. Mononucleate nodules are formed in abyssal environments characterized by lower sedimentation rate where enhanced rates of supply of biogenically derived elements can take place.
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    New Habitat Report for Maldivia trunguiculata (Borradaile) (Brachyura, Xanthidae), a Facultative Symbiont of Porites lobata Dana in Hawaii
    (University of Hawai'i Press, 1982-04) Coles, Stephen L.
    Maldivia triunguiculata (Borradaile), a xanthid crab, lives within chambers in the skeletons oflive Porites lobata corals. The chamber openings are readily recognizable on the live surfaces of P. lobata heads, and chambers penetrate into coral skeletons up to 5.5 cm. Crabs inhabited an average of 85 percent of the chambers investigated. Occupied chambers contained males or females, but never more than one crab per chamber. Areal density of M. triunguiculata on P. lobata increased with increasing coverage of the reef by the live coral, indicating a strong association between the two species. Although M. triunguiculata may occur on dead coral reef, this study indicates that it is more frequently found in live P. lobata.
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    Larval Ascaridoid Nematodes from Fishes near the Hawaiian Islands, with Comments on Pathgenicity Experiments
    (University of Hawai'i Press, 1982-04) Deardorff, Thomas L. ; Kliks, Michael M. ; Rosenfeld, Mitchel E. ; Rychlinski, Robert A. ; Desowitz, Robert S.
    A total of 134 species of finfishes and 8 species of invertebrates, which were caught near the Hawaiian Islands over a 26-month period, were examined for larval nematodes. A total of 21,746 ascaridoid larvae were recovered. Larval nematodes of the genera Anisakis (two types), Hysterothylacium (three types), Raphidascaris (one type), and Terranova (two types) were identified. Descriptions and illustrations are provided for most larvae. A key is included. No anisakine larvae were found in the invertebrates. Inoculations of laboratory rats with various larvae demonstrated that at least Anisakis type II and Terranova type HA harm the host.
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