Water supply and sanitation of Costa Rica     

Kathleen M. Bower 《Environmental Earth Sciences》2014,71(1):107-123

Costa Rica is a developing country whose citizens pride themselves on care for the environment. Environmental care is only slowly spreading to include safe and reliable water supplies. Plentiful water resources are used for energy production, industry, municipal water supply, and agriculture. The amount and quality of water resources must be understood and protected for future sustainable use. Based on interviews and conversations, some Costarricense are aware of the need for protection of natural water resources through preservation of forests; other steps toward sustainable water use are not universally valued. Streams are not the preferred source of domestic water supply due to potential water contamination; mostly from untreated sewage, sediment and agricultural chemicals. Quantity and quality of ground water supplies, the current main source of domestic water, are being investigated by scientists of Costa Rica. While 99 % of the population has access to a known supply of domestic water, only 82 % of the population has consistent access to potable drinking water. The potable water supply is smaller in rural areas. Three percent of sewage in Costa Rica is treated before release to the environment. The Río Tárcoles water basin, underlying the largest urban area of Costa Rica, is probably the most polluted in Central America. More is spent for treatment of water-borne diseases than on water supply and sewage treatment. Other potential sources of water contamination are examined.  相似文献   

Verification of mid-ocean ballast water exchange using naturally occurring coastal tracers   总被引：2，自引：0，他引：2  

Murphy K  Boehme J  Coble P  Cullen J  Field P  Moore W  Perry E  Sherrell R  Ruiz G 《Marine pollution bulletin》2004,48(7-8):711-730

We examined methods for verifying whether or not ships have performed mid-ocean ballast water exchange (BWE) on four commercial vessels operating in the Pacific and Atlantic Oceans. During BWE, a ship replaces the coastal water in its ballast tanks with water drawn from the open ocean, which is considered to harbor fewer organisms capable of establishing in coastal environments. We measured concentrations of several naturally occurring chemical tracers (salinity, six trace elements, colored dissolved organic matter fluorescence and radium isotopes) along ocean transects and in ballast tanks subjected to varying degrees of BWE (0-99%). Many coastal tracers showed significant concentration changes due to BWE, and our ability to detect differences between exchanged and unexchanged ballast tanks was greatest under multivariate analysis. An expanded dataset, which includes additional geographic regions, is now needed to test the generality of our results.  相似文献   

The effect of global warming on mortality     

Jean Calleja-Agius  Kathleen England  Neville Calleja 《Chemie der Erde / Geochemistry》2013

There is a significant relationship between ambient temperature and mortality. In healthy individuals with no underlying co-morbid conditions, there is an efficient heat regulation system which enables the body to effectively handle thermal stress. However, in vulnerable groups, especially in elderly over the age of 65 years, infants and individuals with co-morbid cardiovascular and/or respiratory conditions, there is a deficiency in thermoregulation. When temperatures exceed a certain limit, being cold winter spells or heat waves, there is an increase in the number of deaths. In particular, it has been shown that at temperatures above 27 °C, the daily mortality rate increases more rapidly per degree rise compared to when it drops below 27 °C.This is especially of relevance with the current emergency of global warming. Besides the direct effect of temperature rises on human health, global warming will have a negative impact on primary producers and livestock, leading to malnutrition, which will in turn lead to a myriad of health related issues. This is further exacerbated by environmental pollution.Public health measures that countries should follow should include not only health-related information strategies aiming to reduce the exposure to heat for vulnerable individuals and the community, but improved urban planning and reduction in energy consumption, among many others. This will reduce the carbon footprint and help avert global warming, thus reducing mortality.  相似文献   

Stability of orbits near large mass ratio binary systems     

Natasha Bosanac  Kathleen C. Howell  Ephraim Fischbach 《Celestial Mechanics and Dynamical Astronomy》2015,122(1):27-52

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Cassini RADAR observations of Enceladus, Tethys, Dione, Rhea, Iapetus, Hyperion, and Phoebe     

Steven J. Ostro  Richard D. West  Ralph D. Lorenz  Gregory J. Black  Lauren C. Wye  Stephen D. Wall  Laci Roth  Kathleen Kelleher  Yonggyu Gim  Rudy A. Boehmer  the Cassini RADAR Team 《Icarus》2006,183(2):479-490

Cassini 2.2-cm radar and radiometric observations of seven of Saturn's icy satellites yield properties that apparently are dominated by subsurface volume scattering and are similar to those of the icy Galilean satellites. Average radar albedos decrease in the order Enceladus/Tethys, Hyperion, Rhea, Dione, Iapetus, and Phoebe. This sequence most likely corresponds to increasing contamination of near-surface water ice, which is intrinsically very transparent at radio wavelengths. Plausible candidates for contaminants include ammonia, silicates, metallic oxides, and polar organics (ranging from nitriles like HCN to complex tholins). There is correlation of our targets' radar and optical albedos, probably due to variations in the concentration of optically dark contaminants in near-surface water ice and the resulting variable attenuation of the high-order multiple scattering responsible for high radar albedos. Our highest radar albedos, for Enceladus and Tethys, probably require that at least the uppermost one to several decimeters of the surface be extremely clean water ice regolith that is structurally complex (i.e., mature) enough for there to be high-order multiple scattering within it. At the other extreme, Phoebe has an asteroidal radar reflectivity that may be due to a combination of single and volume scattering. Iapetus' 2.2-cm radar albedo is dramatically higher on the optically bright trailing side than the optically dark leading side, whereas 13-cm results reported by Black et al. [Black, G.J., Campbell, D.B., Carter, L.M., Ostro, S.J., 2004. Science 304, 553] show hardly any hemispheric asymmetry and give a mean radar reflectivity several times lower than the reflectivity measured at 2.2 cm. These Iapetus results are understandable if ammonia is much less abundant on both sides within the upper one to several decimeters than at greater depths, and if the leading side's optically dark contaminant is present to depths of at least one to several decimeters. As argued by Lanzerotti et al. [Lanzerotti, L.J., Brown, W.L., Marcantonio, K.J., Johnson, R.E., 1984. Nature 312, 139-140], a combination of ion erosion and micrometeoroid gardening may have depleted ammonia from the surfaces of Saturn's icy satellites. Given the hypersensitivity of water ice's absorption length to ammonia concentration, an increase in ammonia with depth could allow efficient 2.2-cm scattering from within the top one to several decimeters while attenuating 13-cm echoes, which would require a six-fold thicker scattering layer. If so, we would expect each of the icy satellites' average radar albedos to be higher at 2.2 cm than at 13 cm, as is the case so far with Rhea [Black, G., Campbell, D., 2004. Bull. Am. Astron. Soc. 36, 1123] as well as Iapetus.  相似文献   

TERRESTRIAL VERTEBRATES AND VEGETATION STRUCTURE IN THE WESTERN UNITED STATES     

Thomas R. Vale  Kathleen C. Parker  Albert J. Parker 《The Professional geographer》1989,41(4):450-464

Terrestrial vertebrates in the western United States are functionally linked to environmental settings, as revealed by principal components analyses. Species number in five major vertebrate feeding guilds increases as vegetation structure becomes more complex and environmental conditions become more varied, and as evolutionary history has promoted species richness. Two other major vertebrate feeding guilds increase with temperature and evolutionary factors. Results support the view of animals as adapted parts of deterministic environmental systems, although complete explanations of species distributions require consideration of evolutionary history and stochastic processes.  相似文献   

Trace element and major ion concentrations and dynamics in glacier snow and melt: Eliot Glacier,Oregon Cascades     

Sarah K. Fortner  W. Berry Lyons  Andrew G. Fountain  Kathleen A. Welch  Natalie M. Kehrwald 《水文研究》2009,23(21):2987-2996

We present concentrations of environmentally available (unfiltered acidified 2% v/v HNO₃) As, Cu, Cd, Pb, V, Sr, and major ions including Ca²⁺, Cl^?, and SO₄^2? in a July 2005 and a March 2006 shallow snow profile from the lower Eliot Glacier, Mount Hood, Oregon, and its proglacial stream, Eliot Creek. Low enrichment factors (EF) with respect to crustal averages suggests that in fresh March 2006 snow environmentally available elements are derived primarily from lithogenic sources. Soluble salts occurred in lower and less variable concentrations in July 2005 snow than March 2006. Conversely, environmentally available trace elements occurred in greater and more variable concentrations in July 2005 than March 2006 snow. Unlike major solutes, particulate‐associated trace elements are not readily eluted during the melt season. Additionally, elevated surface concentrations suggest that they are likely added throughout the year via dry deposition. In a 1‐h stream sampling, ratios of dissolved (<0·45 µm) V:Cl^?, Sr:Cl^?, and Cu:Cl^? are enriched in the Eliot Stream with respect to their environmentally available trace element to Cl^? ratios in Eliot Glacier snow, suggesting chemical weathering additions in the stream waters. Dissolved Pb:Cl^? is depleted in the Eliot Stream with respect to the ratio of environmentally available Pb to Cl^? in snow, corresponding to greater adsorption onto particles at greater pH values. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

The Climate Connection – Climate Change and Modern Human Evolution. Renée Hetherington and Robert G. B. Reid, 2010, Cambridge University Press,New York. 440 pp., ISBN‐13: 978‐0‐521‐14723‐1 $44.00 (paperback).     

Kathleen Nicoll 《Geoarchaeology》2012,27(6):542-544

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Pacific Salmon Fisheries: Climate, Information and Adaptation in a Conflict-Ridden Context     

Kathleen A. Miller 《Climatic change》2000,45(1):37-61

Pacific Salmon are anadromous fish that cross state and international boundaries in their oceanic migrations. Fish spawned in the rivers of one jurisdiction are vulnerable to harvest in other jurisdictions. The rocky history of attempts by the United States and Canada to cooperatively manage their respective salmon harvests suggests that such shared resources may present difficult challenges for effective adaptation to climate change. On June 30, 1999, the two nations signed an agreement which, if successfully implemented, may end several years of rancorous conflict. For the previous six years, they had been unable to agree on a full set of salmon "fishing regimes" under the terms of the Pacific Salmon Treaty. This conflict was sparked by strongly divergent trends in the abundance of northern and southern salmon stocks, and a consequent change in the balance of each nation's interceptions of salmon spawned in the other nation's rivers. The trends are attributable, in part, to the effects of large-scale climatic fluctuations. This case demonstrates that it may not be a simple matter to respond effectively to a climate change. Adaptation is difficult when a resource is exploited by multiple competing users who possess incomplete information. If, in addition, their incentives to cooperate are disrupted by the impacts of the climatic variation, dysfunctional breakdowns in management rather than efficient adaptation may ensue. Institutional factors will determine the extent to which the management of such resources can adapt effectively to climate variability or long-term climate change.  相似文献   

Benthic changes during 10 years of organic enrichment by McMurdo Station, Antarctica     

Conlan KE  Kim SL  Lenihan HS  Oliver JS 《Marine pollution bulletin》2004,49(1-2):43-60

A benthic habitat along the coast of McMurdo Station in the Ross Sea, Antarctica is enriched by sewage from the station and altered by hydrocarbons and heavy metals in an adjacent historic dumpsite. We report on 10 years of change in the benthic communities from 1988 to 1998 and compare enrichment effects at Australia's Casey Station, East Antarctica. Despite being 14 km apart, reference communities upcurrent and downcurrent of McMurdo Station remained closely similar over time, dominated in all years by a tube building polychaete, Spiophanes tcherniae. The community bordering McMurdo Station was generally a third as abundant as communities at the reference sites over the decade of sampling, although diversity was as high or higher, except in the most contaminated areas. In 1992, organic enrichment of the outfall community intensified and within the year, the opportunistic polychaetes Aphelochaeta sp., Ophryotrocha notialis, Capitella perarmata, and Leitoscoloplos kerguelensis became dominant. Since 1996, two of the three enriched communities have increased in resemblance to the reference communities. Given the observed responsiveness of the benthos to the outfall so far, further changes are anticipated within the year following implementation of sewage treatment in 2003. Organic enrichment by McMurdo Station has had a greater impact on benthic community structure than at Australia's Casey Station.  相似文献