Biomarkers of early Aptian sediments of the Shatsky Rise

This study investigates organic-rich sedimentary sequences deposited during the early Aptian Oceanic Anoxic Event (OAE1a) at Sites 1207 and 1213 on Shatsky Rise (ODP Leg 198) in the west-central Pacific. Biomarker analyses provide evidence of the algal and bacterial origin of organic matter (OM) in these sediments where the abundance of steroidal components, particularly sterenes and sterones, suggests that the OM includes major contributions from eukaryotic sources in an environment characterized by high phytoplankton productivity. The presence of alkenones at Site 1213B is diagnostic of OM derived from representatives of haptophyte algae among the calcareous nannoplankton and their d13C values (average -31.6 per mil) are consistent with those expected during elevated pCO2. The occurrence and prominence of 2b-methylhopanes and 2b-methylhopanones indicates significant contributions to the OM from cyanobacteria, which are also likely contributors of hopanoids based on their d13C compositions. These biomarker data suggest that oceanic conditions, perhaps nitrate- or iron-limited, were conducive to cyanobacteria production during OAE1a, which appears to distinguish this event from other Cretaceous OAE.

Planktonic foraminiferal abundances and stable isotope ratios in middle Miocene sediments of the North Atlantic and the southwestern Pacific

A three-fold expansion of the Antarctic ice sheet at 13.60, 12.82, and 11.60 Ma has been inferred from delta18O maxima analyzed in planktonic and benthic foraminiferal tests, although accompanying changes in sea surface temperature have not been detailed. We present estimated changes in middle Miocene surface-water temperatures based on analysis of delta18O in planktonic foraminifera collected at mid-latitude Deep Sea Drilling Project sites in the North Atlantic and South Pacific oceans. We also identify periods of ice-sheet growth based on comparisons of benthic and planktonic foraminiferal delta18O values. Our results indicate: (1) a distinct cooling of the sea surface from 13.6 to 13.5 Ma immediately following a peak in ice volume at 13.6 Ma, (2) a cooling of the sea surface during a period of increasing ice volume from 13.2 to 13.0 Ma, and (3) a development of the Antarctic ice sheet during a period of cooling of the sea surface centered at 11.6 Ma.

Pacific Neogene carbonate accumulation rates

I have compiled CaCO3 mass accumulation rates (MARs) for the period 0-25 Ma for 144 Deep Sea Drilling Project and Ocean Drilling Program drill sites in the Pacific in order to investigate the history of CaCO3 burial in the world's largest ocean basin. This is the first synthesis of data since the beginning of the Ocean Drilling Program. Sedimentation rates, CaCO3 contents, and bulk density were estimated for 0.5 Myr time intervals from 0 to 14 Ma and for 1 Myr time intervals from 14 to 25 Ma using mostly data from Initial Reports volumes. There is surprisingly little coherence between CaCO3 MAR time series from different Pacific regions, although regional patterns exist. A transition from high to low CaCO3 MAR from 23-20 Ma is the only event common to the entire Pacific Ocean. This event is found worldwide. The most likely cause of lowered pelagic carbonate burial is a rising sea-level trend in the early Miocene. The central and eastern equatorial Pacific is the only region with adequate drill site coverage to study carbonate compensation depth (CCD) changes in detail for the entire Neogene. The latitude-dependent decrease in CaCO3 production away from the equator is an important defining factor of the regional CCD, which shallows away from the equatorial region. Examination of latitudinal transects across the equatorial region is a useful way to separate the effects of changes in carbonate production ('productivity') from changes in bottom water chemistry ('dissolution') upon carbonate burial.

Chemical composition and age of magmatic rocks from the underwater Hokkaido Rise

Geological and geophysical investigations carried out within the Hokkaido Rise showed that intrusives composing outcrops of the crystalline basement on the ocean floor form a continuous series from monzonites and diorite-monzonites to granites with prevalence of granodiorites with stable mineralogical association: biotite - hornblende - K-feldspar. Acidic volcanic rocks are characterized by a similar mineralogical association with almost complete absence of plagioclase-pyroxene species. It seems that the Hokkaido Rise, as well as the marginal oceanic Zenkevich swell as a whole are not primary oceanic structural formations and have undergone a complex and long history of geological development with intense orogenic movements that occurred in Middle Cretaceous and preceded subalkaline basalt outpouring during postorogenic subsidence of the Earth crust.

Raw-data to morphometric investigations about the Neogene planktonic foraminifer Globorotalia menardii and related forms from ODP Hole 154-925B (Céara Rise, western tropical Atlantic)

Evolutionary prospection is the study of morphological evolution and speciation in calcareous plankton from selected time-slices and key sites in the world oceans. In this context, the Neogene menardiform globorotalids serve as study objects for morphological speciation in planktic foraminifera. A downcore investigation of test morphology of the lineage of G. menardii-limbata-multicamerata during the past 8 million years was carried out in the western tropical Atlantic ODP Hole 925B. A total of 4669 specimens were measured and analyzed from 38 stratigraphic levels and compared to previous studies from DSDP Sites 502 and 503. Collection of digital images and morphometric measurements from digitized outlines were achieved using a microfossil orientation and imaging robot called AMOR and software, which was especially developed for this purpose. Most attention was given to the evolution of spiral height versus axial length of tests in keel view, but other parameters were investigated as well. The variability of morphological parameters in G. menardii, G. limbata, and G. multicamerata through time are visualized by volume density diagrams. At Hole 925B results show gradual test size increase in G. menardii until about 3.2 Ma. The combination of taxonomic determination in the light microscope with morphometric investigations shows strong morphological overlap and evolutionary continuity from ancestral to extant G. menardii (4-6 chambers in the final whorl) to the descendent but extinct G. limbata (seven chambers in the final whorl) and to G. multicamerata (>=8 chambers in the final whorl). In the morphospace defined by spiral height (dX) and axial length (dY) Globorotalia limbata and G. multicamerata strongly overlap with G. menardii. Distinction of G. limbata from G. menardii is only possible by slight differences in the number of chambers of the final whorl, nuances in spiral convexity, upper keel angles, radii of osculating circles, or by differences in reflectance of their tests. Globorotalia multicamerata can be distinguished from the other two forms by more than eight chambers in the final whorl. It appeared as two stratigraphically separate clusters during the Pliocene. Between 2.88 and 2.3 Ma G. menardii was severely restricted in size and abundance. Thereafter, it showed a rapid and prominent expansion of the upper test size extremes between 2.3 and 1.95 Ma persisting until present. The size-frequency distributions at Hole 925B are surprisingly similar to trends of menardiform globorotalids from Caribbean DSDP Site 502. There, the observations were explained as an adaptation to changes in the upper water column due to the emergence of the Isthmus of Panama. In light of more recent paleontological and geological investigations about the completion of the permanent land connection between North and South America since about 3 Ma the present study gives reason to suspect the sudden test size increase of G. menardii to reflect immigration of extra-large G. menardii from the Indian Ocean or the Pacific. It is hypothesized that during the Late Pliocene dispersal of large G. menardii into the southern to tropical Atlantic occurred during an intermittent episode of intense Agulhas Current leakage around the Cape of Good Hope and from there via warm eddy transport to the tropical Atlantic (Agulhas dispersal hypothesis).

Indo-Pacific sea shells; a guide to the common marine snails from East Africa to Polynesia.

Cover title.

A short history of the Middle East, from the rise of Islam to modern times.

Bibliography: p. [283]-286.

A short history of the Middle East, from the rise of Islam to modern times.

Bibliography: p. [283]-286.

Famine relief for East Timor : hearing before the Subcommittee on Asian and Pacific Affairs of the Committee on Foreigh Affairs, House of Representatives, Ninety-sixth Congress, first session, December 4, 1979.

Mode of access: Internet.

Voyages from Montreal through the continent of North America to the frozen and Pacific oceans in 1789 and 1793; with an account of the rise and state of the fur trade.

Introduction signed: Robert Waite.

Supplement to An analysis of the constitution of the East-India company: and of the laws passed by Parliament for the government of their affairs, athome and abroad. To which is prefixed, a brief history of the company, and of the rise and progress of the British power in India /

Mode of access: Internet.

Statistics of petroleum exploration in the Caribbean, Latin America, Western Europe, the Middle East, Africa, non-communist Asia, and the southwestern Pacific /

Mode of access: Internet.

United States security strategy for the East Asia-Pacific Region

Mode of access: Internet.

Neuroprotectant effects of iso-osmolar D-mannitol to prevent Pacific ciguatoxin-1 induced alterations in neuronal excitability: A comparison with other osmotic agents and free radical scavengers

The basis for the neuroprotectant effect of D-mannitol in reducing the sensory neurological disturbances seen in ciguatera poisoning, is unclear. Pacific ciguatoxin-1 (P-CTX-1), at a concentration 10 nM, caused a statistically significant swelling of rat sensory dorsal root ganglia (DRG) neurons that was reversed by hyperosmolar 50 MM D-mannitol. However, using electron paramagnetic resonance (EPR) spectroscopy, it was found that P-CTX-1 failed to generate hydroxyl free radicals at concentrations of toxin that caused profound effects on neuronal excitability. Whole-cell patch-clamp recordings from DRG neurons revealed that both hyper- and iso-osmolar 50 MM D-mannitol prevented the membrane depolarisation and repetitive firing of action potentials induced by P-CTX-1. In addition, both hyper- and iso-osmolar 50 MM D-mannitol prevented the hyperpolarising shift in steady-state inactivation and the rise in leakage current through tetrodotoxin (TTX)-sensitive Na-v channels, as well as the increased rate of recovery from inactivation of TTX-resistant Nav channels induced by P-CTX-1. D-Mannitol also reduced, but did not prevent, the inhibition of peak TTX-sensitive and TTX-resistant I-Na amplitude by P-CTX-1. Additional experiments using hyper- and isoosmolar D-sorbitol, hyperosmolar sucrose and the free radical scavenging agents Trolox (R) and L-ascorbic acid showed that these agents, unlike D-mannitol, failed to prevent the effects of P-CTX-1 on spike electrogenesis and Na-v channel gating. These selective actions of D-mannitol indicate that it does not act purely as an osmotic agent to reduce swelling of nerves, but involves a more complex action dependent on the Nav channel subtype, possibly to alter or reduce toxin association. (c) 2005 Elsevier Ltd. All rights reserved.

The fraction of ischaemic heart disease and stroke attributable to smoking in the WHO Pacific and South-East Asian regions

Background: Tobacco will soon be the biggest cause of death worldwide, with the greatest burden being borne by low and middle-income countries where 8/10 smokers now live. Objective: This study aimed to quantify the direct burden of smoking for cardiovascular diseases (CVD) by calculating the population attributable fractions (PAF) for fatal ischaemic heart disease (IHD) and stroke (haemorrhagic and ischaemic) for all 38 countries in the World Health Organization Western Pacific and South East Asian regions. Design and subjects: Sex-specific prevalence of smoking was obtained from existing data. Estimates of the hazard ratio (HR) for IHD and stroke with smoking as an independent risk factor were obtained from the,600 000 adult subjects in the Asia Pacific Cohort Studies Collaboration (APCSC). HR estimates and prevalence were then used to calculate sex-specific PAF for IHD and stroke by country. Results: The prevalence of smoking in the 33 countries, for which relevant data could be obtained, ranged from 28-82% in males and from 1-65% in females. The fraction of IHD attributable to smoking ranged from 13-33% in males and from < 1-28% in females. The percentage of haemorrhagic stroke attributable to smoking ranged from 4-12% in males and from < 1-9% in females. Corresponding figures for ischaemic stroke were 11-27% in males and < 1-22% in females. Conclusions: Up to 30% of some cardiovascular fatalities can be attributed to smoking. This is likely an underestimate of the current burden of smoking on CVD, given that the smoking epidemic has developed further since many of the studies were conducted.