Lysosomal and microsomal responses to environmental factors in Littorina littorea from Sullom Voe     

Michael N. Moore  Richard K. Pipe  Suzanne V. Farrar 《Marine pollution bulletin》1982,13(10):340-345

The marine gastropod Littorina littorea from four sites in the vicinity of the Sullom Voe Oil Terminal was found to display reduced cytochemically determined latency of lysosomal arylsulphatase, β-glucuronidase and acid phosphatase in comparison with snails from a nearby ‘clean’ site. This is interpreted as indicating lysosomal destabilization by environmental factors. Elevated total activities of particular lysosomal hydrolases were recorded at three of the sites in Sullom Voe. Animals from a fourth site (Swarta Taing) showed significant depression of arylsulphatase and β-glucuronidase. Cytochemically determined activity of blood cell NADPH-neotetrazolium reductase, which is a component of microsomal detoxication systems, was stimulated in these same sites in comparison with the ‘clean’ reference site. This stimulation or induction is interpreted as a response to the presence of oil-derived polynuclear aromatic hydrocarbons.These results are discussed in the light of previous work on the effects of hydrocarbons on lysosomes and in terms of the possible physiological consequences for the animals.  相似文献   

A comparison of the snowmelt energy budgets in two alpine basins     

Mr. R. D. Moore 《Theoretical and Applied Climatology》1983,33(1-2):1-10

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The thorium isotope content of ocean water   总被引：1，自引：0，他引：1  

Willard S. Moore 《Earth and Planetary Science Letters》1981,53(3):419-426

²³²Th concentrations of surface and deep Pacific Ocean waters are 0.01–0.02 dpm/1000 kg (60 pgm/kg). The²³⁰Th activity is 0.03–0.13 dpm/1000 kg in surface waters and 0.3–2.7 dpm/1000 kg in deep waters. Chemical residence times based on in situ production from parent isotopes are about the same for²³⁰Th and²²⁸Th in surface waters (1–5 years) but are ten times greater for²³⁰Th in deep waters (10–100 years). Apparently there are additional sources of²³⁰Th into deep waters. At MANOP site S manganese nodule tops are enriched in Th isotopes by adsorption of Th from seawater and not by incorporation of Th-rich particulates.  相似文献   

Role of glacial Arctic Ocean ice sheets in Pleistocene oxygen isotope and sea level records     

Douglas F. Williams  Willard S. Moore  Richard H. Fillon 《Earth and Planetary Science Letters》1981

A comparison of the oxygen isotope signal in deep-sea benthic foraminifera with the record of glacio-eustatic sea level for the last 160,000 years reveals that the amplitude of the benthic δ¹⁸O records predicts more continental ice volume than appears to be reflected in lowered sea level stands. These differences between the benthic δ¹⁸O ice volume estimates and radiometrically-dated records of eustatic sea level are consistent with the presence of a large floating Arctic Ocean ice mass during glacial intervals. The presence of an Arctic Ocean ice sheet during glacial intervals may account for the two climatic modes observed in oxygen isotope records which span the entire Pleistocene. The early Pleistocene (1.8 to 0.9 Myr B.P.) interval is characterized by low-amplitude, high-frequency δ¹⁸O fluctuations between glacial and interglacial periods, while the late Pleistocene (0.9 Myr B.P. to present) is characterized by large-amplitude, low-frequency δ¹⁸O changes. These two climatic modes can be explained by the initiation of earth orbital conditions favoring the co-occurrence of glacial period Arctic Ocean ice sheets and large continental ice sheets approximately 900,000 years before present.  相似文献   

The evolution of Pleistocene climate: A time series approach     

N.G. Pisias  T.C. Moore 《Earth and Planetary Science Letters》1981,52(2):450-458

In the later part of the Pleistocene, variations in global ice volume have been dominated by an approximate 100,000-year cycle. Analysis of 2-Myr-long oxygen isotope record from an equatorial Pacific core indicates that this is true only for the last 900,000 years. Prior to this time the amplitude of the 100,000-year cycle is much reduced, as is the variance of all oscillations with periods greater than 60,000 years. Based on results of time series analysis of this 2-Myr-long record, the Pleistocene glacial cycles can be divided into three sections: (1) the late Pleistocene (0–900 kyr B.P.) where the variations in the isotope record are dominated by the 100,000-year cycle; (2) the middle Pleistocene (900–1450 kyr B.P.) in which low-frequency components are not as important as in the later period of the Pleistocene, and (3) the early Pleistocene/late Pliocene (1450–2000 kyr B.P.) where general reductions of importance at all frequencies is seen as compared to the later intervals. Recent modeling efforts which describe variations in global ice volume show that the dominant low-frequency component observed in the late Pleistocene can result from different time constants for the rate of glacial growth and decay in response to variations in the Earth's orbital parameters. It is hypothesized that during the early Pleistocene the rate of growth and decay of glaciers were more similar and that continental erosion by successive glacial advances lowered the land surface in areas of ice-cap formation to below sea level. When the ice caps became marine-based, more rapid decay of the ice became possible.  相似文献   

Metals in seafood organisms near a large California municipal outfall     

D.R. Young  M.D. Moore  T.-K. Jan  R.P. Eganhouse 《Marine pollution bulletin》1981,12(4):134-138

With the possible exception of copper and zinc, eight trace metals in muscle tissue of five popular benthic-feeding sportsfishes caught near the Los Angeles County municipal wastewater outfalls were not concentrated above levels measured in island and coastal control specimens. In contrast, the edible portions of five invertebrate seafood organisms collected from the highly contaminated bottom sediments in this discharge zone did concentrate some of the metals several-fold above control values. The maximum contamination observed was a 10-fold elevation of chromium in abalone and scallop muscle.  相似文献   

On the magnetic structure of the quiet transition region     

James F. Dowdy Jr.  Douglas Rabin  Ronald L. Moore 《Solar physics》1986,105(1):35-45

Existing models of the quiet chromosphere-corona transition region predict a distribution of emission measure over temperature that agrees with observation for T 10⁵ K. These network models assume that all magnetic field lines that emerge from the photosphere extend into and are in thermal contact with the corona. We show that the observed fine-scale structure of the photospheric magnetic network instead suggests a two-component picture in which magnetic funnels that open into the corona emerge from only a fraction of the network. The gas that makes up the hotter transition region is mostly contained within these funnels, as in standard models, but, because the funnels are more constricted in our picture, the heat flowing into the cooler transition region from the corona is reduced by up to an order of magnitude. The remainder of the network is occupied by a population of low-lying loops with lengths 10⁴ km. We propose that the cooler transition region is mainly located within such loops, which are magnetically insulated from the corona and must, therefore, be heated internally. The fine-scale structure of ultraviolet spectroheliograms is consistent with this proposal, and theoretical models of internally heated loops can explain the behavior of the emission measure below T 10⁵ K.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.  相似文献   

East Asia plate tectonics since 15 Ma: constraints from the Taiwan region   总被引：4，自引：0，他引：4  

Jean-Claude Sibuet  Shu-Kun Hsu  Xavier Le Pichon  Jean-Pierre Le Formal  Donald Reed  Greg Moore  Char-Shine Liu   《Tectonophysics》2002,344(1-2)

15 Ma ago, a major plate reorganization occurred in East Asia. Seafloor spreading ceased in the South China Sea, Japan Sea, Taiwan Sea, Sulu Sea, and Shikoku and Parece Vela basins. Simultaneously, shear motions also ceased along the Taiwan–Sinzi zone, the Gagua ridge and the Luzon–Ryukyu transform plate boundary. The complex system of thirteen plates suddenly evolved in a simple three-plate system (EU, PH and PA). Beneath the Manila accretionary prism and in the Huatung basin, we have determined magnetic lineation patterns as well as spreading rates deduced from the identification of magnetic lineations. These two patterns are rotated by 15°. They were formed by seafloor spreading before 15 Ma and belonged to the same ocean named the Taiwan Sea. Half-spreading rate in the Taiwan Sea was 2 cm/year from chron 23 to 20 (51 to 43 Ma) and 1 cm/year from chron 20 (43 Ma) to 5b (15 Ma). Five-plate kinematic reconstructions spanning from 15 Ma to Present show implications concerning the geodynamic evolution of East Asia. Amongst them, the 1000-km-long linear Gagua ridge was a major plate boundary which accommodated the northwestward shear motion of the PH Sea plate; the formation of Taiwan was driven by two simple lithospheric motions: (i) the subduction of the PH Sea plate beneath Eurasia with a relative westward motion of the western end (A) of the Ryukyu subduction zone; (ii) the subduction of Eurasia beneath the Philippine Sea plate with a relative southwestward motion of the northern end (B) of the Manila subduction zone. The Luzon arc only formed south of B. The collision of the Luzon arc with Eurasia occurred between A and B. East of A, the Luzon arc probably accreted against the Ryukyu forearc.  相似文献   

Little Ice Age recorded in summer temperature reconstruction from vared sediments of Donard Lake, Baffin Island, Canada     

J.J. Moore  K.A. Hughen  G.H. Miller  J.T. Overpeck 《Journal of Paleolimnology》2001,25(4):503-517

Clastic varved sediments from Donard Lake, in the Cape Dyer region of Baffin Island, provide a 1250 yr record of decadal-to-centennial scale climate variability. Donard Lake experiences strong seasonal fluctuations in runoff and sediment fluxes due to the summer melting of the Caribou Glacier, which presently dominates its catchment. The seasonal variation in sediment supply results in the annual deposition of laminae couplets. A radiocarbon date measured on moss fragments, with a calibrated age of 860 ± 80 yrs before present (BP), is in close agreement with the age based on paired-layer counts. Together with the fabric of the laminae determined from microscope analysis, the age agreement demonstrates that the laminae couplets are annually deposited varves. Comparisons of varve thickness and average summer temperature from nearby Cape Dyer show a significant positive correlation (r= 0.57 for annual records, r = 0.82 for 3-yr averages), indicating that varve thickness reflects changes in average summer temperature. Varve thickness was used to reconstruct average summer temperatures for the past 1250 yrs, and shows abrupt shifts and large amplitude decadal-to-centennial scale variability throughout the record. The most prominent feature of the record is a period of elevated summer temperatures from 1200-1375 AD, followed by cooler conditions from 1375-1820 AD, coincident with the Little Ice Age.  相似文献   

The use of various interplanetary scintillation indices within geomagnetic forecasts     

E. A. Lucek  T. D. G. Clark  V. Moore 《Annales Geophysicae》1996,14(2):139-148

Interplanetary scintillation (IPS), the twinkling of small angular diameter radio sources, is caused by the interaction of the signal with small-scale plasma irregularities in the solar wind. The technique may be used to sense remotely the near-Earth heliosphere and observations of a sufficiently large number of sources may be used to track large-scale disturbances as they propagate from close to the Sun to the Earth. Therefore, such observations have potential for use within geomagnetic forecasts. We use daily data from the Mullard Radio Astronomy Observatory, made available through the World Data Centre, to test the success of geomagnetic forecasts based on IPS observations. The approach discussed here was based on the reduction of the information in a map to a single number or series of numbers. The advantages of an index of this nature are that it may be produced routinely and that it could ideally forecast both the occurrence and intensity of geomagnetic activity. We start from an index that has already been described in the literature, INDEX35. On the basis of visual examination of the data in a full skymap format modifications were made to the way in which the index was calculated. It was hoped that these would lead to an improvement in its forecasting ability. Here we assess the forecasting potential of the index using the value of the correlation coefficient between daily Ap and the IPS index, with IPS leading by 1 day. We also compare the forecast based on the IPS index with forecasts of Ap currently released by the Space Environment Services Center (SESC). Although we find that the maximum improvement achieved is small, and does not represent a significant advance in forecasting ability, the IPS forecasts at this phase of the solar cycle are of a similar quality to those made by SESC.  相似文献