ment of green technologies, including electric and hybrid vehicles, compact and long-life LED lights, and wind power generation, is required to shift human society toward sustainable growth. Rare-earth elements and yttrium, hereinafter together called REY, are essential elements for products with these advanced and green technologies, because of the magnetic and optical properties of REY that result from the characteristic configurations of electrons in these elements. With rising economic growth in

Samples from three submerged sites (MC, a core obtained in the methane seep area; MR, a reference core obtained at a distance from the methane seep; and HC, a gas-bubbling carbonate sample) at the Kuroshima Knoll in the southern Ryuku arc were analyzed to gain insight into the organisms present and the processes involved in this oxic-anoxic methane seep environment. 16S rRNA gene analyses by quantitative real-time PCR and clone library sequencing revealed that the MC core sediments contained abundant archaea (ϳ34% of the total prokaryotes), including both mesophilic methanogens related to the genus Methanolobus and ANME-2 members of the Methanosarcinales, as well as members of the ␦-Proteobacteria, suggesting that both anaerobic methane oxidation and methanogenesis occurred at this site. In addition, several functional genes connected with methane metabolism were analyzed by quantitative competitive-PCR, including the genes encoding particulate methane monooxygenase (pmoA), soluble methane monooxygenase (mmoX), methanol dehydrogenese (mxaF), and methyl coenzyme M reductase (mcrA). In the MC core sediments, the most abundant gene was mcrA (2.5 ؋ 10 6 copies/g [wet weight]), while the pmoA gene of the type I methanotrophs (5.9 ؋ 10 6 copies/g [wet weight]) was most abundant at the surface of the MC core. These results indicate that there is a very complex environment in which methane production, anaerobic methane oxidation, and aerobic methane oxidation all occur in close proximity. The HC carbonate site was rich in ␥-Proteobacteria and had a high copy number of mxaF (7.1 ؋ 10 6 copies/g [wet weight]) and a much lower copy number of the pmoA gene (3.2 ؋ 10 2 copies/g [wet weight]). The mmoX gene was never detected. In contrast, the reference core contained familiar sequences of marine sedimentary archaeal and bacterial groups but not groups specific to C 1 metabolism. Geochemical characterization of the amounts and isotopic composition of pore water methane and sulfate strongly supported the notion that in this zone both aerobic methane oxidation and anaerobic methane oxidation, as well as methanogenesis, occur.

Coral reefs are tropic to subtropic, coastal ecosystems comprising very diverse organisms. Late Quaternary reef deposits are fossil archives of environmental, tectonic and eustatic variations that can be used to reconstruct the paleoclimatic and paleoceanographic history of the tropic surface oceans. Reefs located at the latitudinal limits of coralreef ecosystems (i.e. those at coral-reef fronts) are particularly sensitive to environmental changes -especially those associated with glacial-interglacial changes in climate and sealevel. We propose a land and ocean scientific drilling campaign in the Ryukyu Islands (the Ryukyus) in the northwestern Pacific Ocean to investigate the dynamic response of the corals and coral-reef ecosystems in this region to Late Quaternary climate and sealevel change. Such a drilling campaign, which we call the COREF (coral-reef front) Project, will allow the following three major questions to be evaluated: (i) What are the nature, magnitude and driving mechanisms of coral-reef front migration in the Ryukyus? (ii) What is the ecosystem response of coral reefs in the Ryukyus to Quaternary climate changes? (iii) What is the role of coral reefs in the global carbon cycle? Subsidiary objectives include (i) the timing of coral-reef initiation in the Ryukyus and its causes; (ii) the position of the Kuroshio current during glacial periods and its effects on coral-reef formation; and (iii) early carbonate diagenetic responses as a function of compounded variations in climate, eustacy and depositional mineralogies (subtropic aragonitic to warm-temperate calcitic). The geographic, climatic and oceanographic settings of the Ryukyu Islands provide an ideal natural laboratory to address each of these research questions.

We report detailed lithological and chemical characteristics of deep-sea sediments, including rare-earth elements and yttrium-rich mud (REY-rich mud), in the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island. Three research cruises obtained fourteen sediment cores collected by piston coring. Based on the visual descriptions and geochemical analysis of the sediment cores, we confirm the presence of REY-rich mud containing more than 400 ppm total REY (ÂREY) in the southern and northwestern areas of the Minamitorishima EEZ. The REY-rich mud layers are characterized by abundant grains of phillipsite, biogenic calcium phosphate, and manganese oxides, and are widely distributed in relatively shallow depths beneath the seafloor. In contrast, relatively thick, non-REY-rich mud lies near the seafloor in the northern areas of the EEZ. In the three cores from the southern part of the EEZ, we also confirm the presence of highly/extremely REY-rich mud layers. Further accumulation of geochemical data from the sediments will be required to constrain the extent of the highly/extremely REY-rich mud layers.

Bryozoan-rich biogenic mounds grew periodically on the prograding carbonate slope of the central Great Australian Bight throughout Pliocene-Pleistocene time. Cores from three ODP Leg 182 drill sites provide a record of mound growth during the last 300,000 years over a stratigraphic thickness of ϳ 150 m. These mounds, the first such structures described from the modern ocean, grew between paleodepths of 100 and 240 m; we infer that the upper limit of growth was established by swell wave base, and the lower boundary was fixed by an oligotrophic water mass. Detailed chronostratigraphy, based on radiometric and U-series dating, benthic foraminifer stable-isotope stratigraphy, and planktonic foraminifer abundance ratios, confirms that buildups flourished during glacial lowstands (even-numbered marine isotope stages) but were largely moribund during interglacial highstands and are not extant today.Mound floatstones are compositionally a mixture of in situ bryozoans comprising 96 genera and characterized by fenestrate, flat robust branching, encrusting, nodular-arborescent, and delicate branching growth forms. The packstone matrix comprises autochthonous and allochthonous sand-size bryozoans, benthic and planktonic foraminifers, serpulids, coralline algae, sponge spicules, peloids, and variable glauconite and quartz grains, together with mud-size ostracods, tunicate spicules, bioeroded sponge chips, and coccoliths. Intermound, allochthonous packstone and local grainstone contain similar particles, but they are conspicuously worn, abraded, blackened, and bioeroded.An integrated model of mound accretion during sea-level lowstands begins with delicate branching bryozoan floatstone that increases in bryozoan abundance and diversity upward over a thickness of 5-10 m, culminating in thin intervals of grainstone characterized by reduced diversity and locally abraded fossils. Mound accumulation was relatively rapid (30-67 cm/ky) and locally punctuated by rudstones and firmgrounds. Intermound highstand deposition was comparatively slow (17-25 cm/ky) and typified by meter-scale, fining-upward packages of packstone and grainstone or burrowed packstone, with local firmgrounds overlain by characteristically abraded particles.Mound growth during glacial periods is interpreted to have resulted from increased nutrient supply and enhanced primary productivity. Such elevated trophic resources were both regional and local, and thought to be focused in this area by cessation of Leeuwin Current flow, together with northward movement of the subtropical convergence and related dynamic mixing.