Survivorship and growth of Fucus gardneri after transplant to an acid mine drainage-polluted area     

Marsden AD  DeWreede RE  Levings CD 《Marine pollution bulletin》2003,46(1):65-73

Acid mine drainage (AMD) from an abandoned copper mine at Britannia Beach, British Columbia, Canada, enters the marine environment through Britannia Creek. The surrounding intertidal zone is devoid of rockweed, Fucus gardneri Silva, a seaweed that dominates nearby shores. Rockweed plants were transplanted to the intertidal zone near Britannia Creek and monitored for changes in percent cover, survivorship, growth rate and Cu content. Autumn and winter transplants to within 100 m of Britannia Creek resulted in negative growth rates and high mortality within 57 days of exposure to AMD, with Cu levels in rockweed surpassing 2,300 ppm in dry tissue. Summer transplants to sites 300-700 m from Britannia Creek showed no consistent differences between AMD-exposed rockweed and control plants, possibly because the plants were stressed by desiccation. The results are consistent with ecological effects observed in other studies, and provide strong evidence for the role of AMD in excluding rockweed from the shores near Britannia Creek.  相似文献   

The 1.95-2.50 μm Spectrum of J6 Himalia     

Thomas R. GeballeC.M.Dalle Ore  Dale P. CruikshankT.C. Owen 《Icarus》2002,159(2):542-544

The reflectance spectrum of Jupiter's sixth satellite, Himalia, is featureless in the wavelength region 1.95-2.50 μm as seen at a spectral resolution of 0.005 μm, with no absorptions deeper than a few percent. From model calculations we establish an upper limit of 10% by weight of H₂O (30-μm grains) mixed intimately in the soil of Himalia, or alternatively 0.3% of the surface covered by exposures of H₂O ice spatially segregated from the darker soil. For CH₄ and CO₂ ices the upper limits in spatially segregated models are both 0.3%.  相似文献   

Preliminary evidence for human fecal contamination in corals of the Florida Keys,USA   总被引：6，自引：0，他引：6  

Lipp EK  Jarrell JL  Griffin DW  Lukasik J  Jacukiewicz J  Rose JB 《Marine pollution bulletin》2002,44(7):666-670

Corals and reef environments are under increased stress from anthropogenic activities, particularly those in the vicinity of heavily populated areas such as the Florida Keys. The potential adverse impacts of wastewater can affect both the environment and human health; however, because of the high decay rate of bacterial indicators in coral reef waters it has been difficult to document the presence of microbial contaminants and to assign risks in these environments. Here we show initial evidence that microorganisms associated with human feces are concentrated along the surface of coral heads relative to the overlying water column in the Florida Keys. Bacterial indicators (fecal coliform bacteria, enterococci or Clostridium perfringens) were detected in 66.7% of the coral surface microlayer (CSM) samples at levels between five and 1000 CFU/100 ml, but were found infrequently and at low numbers in the overlying water column ( < or = 2.5 CFU/100 ml). Similarly, enterovirus nucleic acid sequences, an indicator of human-specific waste, were detected in 93.3% of the CSM samples and only once in the water column by cell culture. Results show that coral mucus may accumulate enteric microorganisms in reef environments, and may indicate a risk to public and environmental health despite low indicator levels in the surrounding water.  相似文献   

An American Paradox     

Dale Jamieson 《Climatic change》2006,77(1-2):97-102

This paper explores the paradox that while Americans generally identify themselves as environmentalists, they show little willingness to voluntarily restrain their behavior or to support specific fiscal policies that would result in increased levels of environmental protection. I explore the role of values in the explanation of this paradox, and discuss some of the difficulties involved in studying values and their role in human behavior.  相似文献   

The use of ²¹⁰Pb as a heavy metal tracer in the Susquehanna River system     

Dale M Lewis 《Geochimica et cosmochimica acta》1977,41(11):1557-1564

Analysis of soil profiles and shallow ground water in the Susquehanna River basin, northeastern U.S.A., indicates that the atmospheric flux of ²¹⁰Pb is efficiently scavenged by the organic-rich horizons of the soils. This atmospherically supplied ²¹⁰Pb in soil profiles can only be lost from the system by soil erosion. Based on the annual sediment yield of the Susquehanna River and the excess ²¹⁰Pb concentration in particulate matter, a mean residence time of 2000 yr is calculated for metals similar to Pb in soil profiles.The West Branch of the Susquehanna River (WBSR) is strongly affected by acid mine drainage and is low in pH and high in dissolved ( <0.4 μm) ²¹⁰Pb, Fe and Mn. Along its course iron hydroxide is precipitating at a pH of between 4 and 4.5 and the ²¹⁰Pb supplied by the acid mine water is diminished by about 25% as a result of dilution. As the WBSR enters the Valley and Ridge Province of the Appalachians it has a ²¹⁰Pb concentration of ~ 0.2 dpm/l. At this juncture it receives a considerable influx of alkalinity from tributaries draining carbonate terranes, resulting in neutralization of the sulfuric acid and increase of the river pH to around 6.5–7. This pH adjustment is accompanied by the precipitation of Fe and Mn. Due to the slow rate of Mn removal from solution, the Mn precipitation extends a considerable distance down river from the point of acid neutralization. Analyses for ²¹⁰Pb in the river at points in or below the region of Mn precipitation show that ²¹⁰Pb is rapidly scavenged from solution onto suspended particles. From the data it is possible to calculate the removal rate of Pb from water in the presence of Fe and Mn hydroxides and other particles. At a pH of 4–4.5 Pb removal is nonexistent relative to the river flow rate, but at a pH of 6.5–7 the ²¹⁰Pb data indicate a residence time of <0.7 day for dissolved Pb.  相似文献   

The influence of wind-driven currents on the circulation and bay dynamics of a semi-enclosed reefal bay,Wreck Bay,Jamaica     

Ava M. Maxam  Dale F. Webber 《Estuarine, Coastal and Shelf Science》2010

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Variations in 24-μm morphologies among galaxies in the Spitzer Infrared Nearby Galaxies Survey: new insights into the Hubble sequence     

G. J. Bendo  D. Calzetti  C. W. Engelbracht  R. C. Kennicutt Jr    M. J. Meyer  M. D. Thornley  F. Walter  D. A. Dale  A. Li  E. J. Murphy 《Monthly notices of the Royal Astronomical Society》2007,380(4):1313-1334

To study the distribution of star formation and dust emission within nearby galaxies, we measured five morphological parameters in the 3.6- and 24-μm wavebands for 65 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS) and eight galaxies that were serendipitously observed by SINGS. The morphological parameters demonstrate strong variations along the Hubble sequence, including statistically significant differences between S0/a-Sab and Sc-Sd galaxies. Early-type galaxies are generally found to be compact, centralized, symmetric sources in the 24-μm band, while late-type galaxies are generally found to be extended, asymmetric sources. These results suggest that the processes that increase the real or apparent sizes of galaxies' bulges also lead to more centralized 24-μm dust emission. Several phenomena, such as strong nuclear star formation, Seyfert activity, or outer ring structures, may cause galaxies to deviate from the general morphological trends observed at 24 μm. We also note that the 24-μm morphologies of Sdm-Im galaxies are quite varied, with some objects appearing very compact and symmetric but others appearing diffuse and asymmetric. These variations reflect the wide variation in star formation in irregular galaxies as observed at other wavelengths. The variations in the 24-μm morphological parameters across the Hubble sequence mirror many of the morphological trends seen in other tracers of the ISM and in stellar emission. However, the 24-μm morphological parameters for the galaxies in this sample do not match the morphological parameters measured in the stellar wavebands. This implies that the distribution of dust emission is related to but not equivalent to the distribution of stellar emission.  相似文献   

THE FIFTH INTERNATIONAL CONFERENCE ON CARTOGRAPHY     

P. F. Dale 《The Photogrammetric Record》1970,6(36):647-648

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Mangrove expansion and rainfall patterns in Moreton Bay, Southeast Queensland, Australia     

L. Eslami-Andargoli  Per Dale  N. Sipe  J. Chaseling 《Estuarine, Coastal and Shelf Science》2009,85(2):292-298

Changes in rainfall pattern have been suggested as a mechanism for the landward incursion of mangrove into salt marsh. The aim of the research was to assess the relationship between rainfall patterns and the spatial distribution of mangrove forests at study sites in Moreton Bay, Southeast Queensland, Australia, over a 32-year period from 1972 to 2004. To identify periods of relatively consistent rainfall patterns points at which rainfall patterns changed (change-points) were identified using the non-parametric Pettitt–Mann–Whitney-Statistic and the cumulative sum technique. The change-points were then used to define the temporal periods over which changes to mangrove area were assessed. Both mangrove and salt marsh area were measured by digitizing aerial photographs acquired in 1972, 1990 (the year with the most significant change-point), and 2004. The rates of change in mangrove area pre-1990 (a wetter period) and post-1990 (a drier period) were estimated. A significant positive relationship was demonstrated between rainfall variables and landward mangrove expansion, but not for seaward expansion. We concluded that rainfall variability is one of the principal factors influencing the rate of upslope encroachment of mangrove. However, the rate of expansion may vary from site to site due to site-specific geomorphological and hydrological characteristics and the level of disturbance in the catchment.  相似文献   

Secular tidal changes in lunar orbit and Earth rotation     

James?G.?WilliamsEmail authorView author&#;s OrcID profile  Dale?H.?Boggs 《Celestial Mechanics and Dynamical Astronomy》2016,126(1-3):89-129

Small tidal forces in the Earth–Moon system cause detectable changes in the orbit. Tidal energy dissipation causes secular rates in the lunar mean motion n, semimajor axis a, and eccentricity e. Terrestrial dissipation causes most of the tidal change in n and a, but lunar dissipation decreases eccentricity rate. Terrestrial tidal dissipation also slows the rotation of the Earth and increases obliquity. A tidal acceleration model is used for integration of the lunar orbit. Analysis of lunar laser ranging (LLR) data provides two or three terrestrial and two lunar dissipation parameters. Additional parameters come from geophysical knowledge of terrestrial tides. When those parameters are converted to secular rates for orbit elements, one obtains dn/dt = \(-25.97\pm 0.05 ''/\)cent\(^{2}\), da/dt = 38.30 ± 0.08 mm/year, and di/dt = ?0.5 ± 0.1 \(\upmu \)as/year. Solving for two terrestrial time delays and an extra de/dt from unspecified causes gives \(\sim \) \(3\times 10^{-12}\)/year for the latter; solving for three LLR tidal time delays without the extra de/dt gives a larger phase lag of the N2 tide so that total de/dt = \((1.50 \pm 0.10)\times 10^{-11}\)/year. For total dn/dt, there is \(\le \)1 % difference between geophysical models of average tidal dissipation in oceans and solid Earth and LLR results, and most of that difference comes from diurnal tides. The geophysical model predicts that tidal deceleration of Earth rotation is \(-1316 ''\)/cent\(^{2}\) or 87.5 s/cent\(^{2}\) for UT1-AT, a 2.395 ms/cent increase in the length of day, and an obliquity rate of 9 \(\upmu \)as/year. For evolution during past times of slow recession, the eccentricity rate can be negative.  相似文献