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11.
Mapping ambivalence: Exploring the geographies of community change and rails-to-trails development using photo-based Q method and PPGIS 总被引:5,自引:0,他引:5
As the literature on trail development suggests, recreational trail projects can generate conflicts and controversies, particularly when built on abandoned rail corridors through developed areas. These conflicts are often understood as “not in my back yard” (NIMBY) reactions, suggesting a spatial proximity to conflict which increases as one draws closer to the proposed trail. This research seeks to understand local residents’ perceptions and reactions to recreational trail development in the City of Delaware (Ohio, USA). It addresses two spatially infused questions: Does the potential for conflict related to trail development increase as people live closer to a potential trail (the NIMBY factor)? Can important qualitative factors about favorable and unfavorable land uses including potential recreational trail sites be defined using a participatory methodology and then represented in GIS? The study used a mixed-method approach to collect and analyze qualitative data from a group of local residents. Each participant was interviewed and asked to sort 19 pictures related to trail development. After each of the sorts, participants were asked to explain why they ranked the pictures the way they did. Results of the picture sorts were then analyzed using Q method and mapped with GIS. The results show that spatial proximity matters in the context of trail development and potential NIMBY reactions to trails. Significant differences were found in the picture sorts that reveal the importance of proximity and location, although in a manner contrary to the assumptions in the writings on rails-to-trails. Through combining qualitative methods, Q analysis and PPGIS analysis, the research shows that qualitative place-based studies are capable of generating insights about the complexities of situated geographic change such as recreational trail development. 相似文献
12.
Tilapia is a common fish species inhabiting inland waters and estuarine regions in Hong Kong and Southeast Asia, and useful for bio-monitoring of metal pollution. Metallothionein (MT) gene expression in fish tissues has been useful to sub-lethal risk assessment as biomarker of exposure to metal ions in fishes inhabiting metal contaminated area. To investigate metal inductions of Tilapia MT gene expression in vivo, Tilapias were injected with different concentrations of heavy metals and tissues were then removed for quantitative PCR assay using mimic PCR methods. All of the metal ions tested (Cu(2+), Cd(2+), Hg(2+), Ni(2+), Pb(2+) and Zn(2+)) were able to induce hepatic MT mRNA levels. Renal MT mRNA levels of Cd(2+) and Zn(2+) treated fish was not induced with significant fold induction, however MT mRNA levels in gills were sensitive to the administrations of these metal ions. These data indicated that Tilapia MT mRNA levels in gills and liver are sensitive biomarker of exposure to various metal ions. 相似文献
13.
Louis I. Gordon P. Kilho Park Stephen W. Hager Timothy R. Parsons 《Journal of Oceanography》1971,27(3):81-90
Observations were made of time variations of the carbon dioxide partial pressures (Pco2) of the atmosphere and surface sea waters in the Pacific subarctic region. Data were obtained on a cruise of the USC & GSSSURVEYOR in October, 1968 and on the TRANSPAC expedition of the CNAVENDEAVOUR in March–April, 1969. A rise in surface water Pco2 of 18×10–6 atm occurred in a period of 30–45 days in March–April due principally to spring warming of surface waters. An average increase of 60×10–6 atm occurred between October, 1968 and March, 1969 as a result mainly of cessation of summer phytoplankton production and the onset of winter-storm-driven vertical mixing. Because the air-sea Pco2 gradient not only changed appreciably in magnitude but also changed sign, there are important implications for calculations of air-sea exchange of carbon dioxide on the ocean wide scale.Data contained in this paper comprise part of a dissertation to be submitted by Louis I. Gordon in partial fulfillment of the requirements for the Ph. D. at Oregon State University. 相似文献
14.
Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates 总被引:1,自引:0,他引:1
Sedimentary records of naturally occurring and fallout-derived radionuclides are widely used as tools for estimating both the ages of recent sediments and rates of sedimentation and bioturbation. Developing these records to the point of data interpretation requires careful sample collection, processing, analysis and data modeling. In this work, we document a number of potential pitfalls that can impact sediment core records and their interpretation. This paper is not intended as an exhaustive treatment of these potential problems. Rather, the emphasis is on potential problems that are not well documented in the literature, as follows: (1) the mere sampling of sediment cores at a resolution that is too coarse can result in an apparent diffusive mixing of the sedimentary record at rates comparable to diffusive bioturbation rates observed in many locations; (2) 210Pb profiles in slowly accumulating sediments can easily be misinterpreted to be driven by sedimentation, when in fact bioturbation is the dominant control. Multiple isotopes of different half lives and/or origin may help to distinguish between these two possible interpretations; (3) apparent mixing can occur due simply to numerical artifacts inherent in the finite difference approximations of the advection diffusion equation used to model sedimentation and bioturbation. Model users need to be aware of this potential problem. Solutions to each of these potential pitfalls are offered to ensure the best possible sediment age estimates and/or sedimentation and bioturbation rates can be obtained. 相似文献
15.
Brent L. Lewis Brian T. Glazer Paul J. Montbriand George W. Luther III Donald B. Nuzzio Timothy Deering Shufen Ma Stephen Theberge 《Marine Chemistry》2007,105(3-4):296-308
A combination of CTD casts, discrete bottle sampling and in situ voltammetric microelectrode profiling was used to examine changing redox conditions in the water column at a single station south of the Bay Bridge in the upper Chesapeake Bay in late July/early August, 2002–2005. Short-term (2–4 h) fluctuations in the oxic/suboxic/anoxic interface were documented using in situ voltammetric solid-state electrodes. Profiles of dissolved oxygen and sulfide revealed tidally-driven vertical fluctuations of several meters in the depth and thickness of the suboxic zone. Bottom water concentrations of sulfide, Mn2+ and Fe2+ also varied over the tidal cycle by approximately an order of magnitude. These data indicate that redox species concentrations at this site varied more due to physical processes than biogeochemical processes. Based on analysis of ADCP data, tidal currents at this station were strongly polarized, with the principal axis of tidal currents aligned with the mainstem channel. Together with the chemical data, the ADCP analysis suggests tidal flushing of anoxic bottom waters with suboxic water from north of the site. The present study is thus unique because while most previous studies have focused on processes across relatively stable redox interfaces, our data clearly demonstrate the influence of rapidly changing physical mixing processes on water column redox chemistry.Also noted during the study were interannual differences in maximum bottom water concentrations of sulfide, Mn2+ and Fe2+. In 2003, for example, heavy spring rains resulted in severe hypoxia/anoxia in June and early July. While reported storm-induced mixing in late July/early August 2003 partially alleviated the low-oxygen conditions, bottom water concentrations of sulfide, Mn2+ and Fe2+ were still much higher than in the previous year. The latter implies that the response time of the microbial community inhabiting the suboxic/anoxic bottom waters to changing redox conditions is slow compared to the time scale of episodic mixing events. Bottom water concentrations of the redox-sensitive chemical species should thus be useful as a tracer to infer prior hypoxic/anoxic conditions not apparent from ambient oxygen levels at the time of sampling. 相似文献
16.
Timothy M. Dellapenna Mead A. Allison Gary A. Gill Ronald D. Lehman Kent W. Warnken 《Estuarine, Coastal and Shelf Science》2006,69(3-4):519
To address the relative importance of shrimp trawling on seabed resuspension and bottom characteristics in shallow estuaries, a series of disturbance and monitoring experiments were conducted at a bay bottom mud site (2.5 m depth) in Galveston Bay, Texas in July 1998 and May 1999. Based on pre- and post-trawl sediment profiles of 7Be; pore water dissolved oxygen and sulfide concentration; and bulk sediment properties, it was estimated that the trawl rig, including the net, trawl doors, and “tickler chain,” excavate the seabed to a maximum depth of approximately 1.5 cm, with most areas displaying considerably less disturbance. Water column profile data in the turbid plume left by the trawl in these underconsolidated muds (85–90% porosity; <0.25 kPa undrained shear strength) demonstrate that suspended sediment inventories of up to 85–90 mg/cm2 are produced immediately behind the trawl net; an order of magnitude higher than pre-trawl inventories and comparable to those observed during a 9–10 m/s wind event at the study site. Plume settling and dispersion caused suspended sediment inventories to return to pre-trawl values about 14 min after trawl passage in two separate experiments, indicating particles re-settle primarily as flocs before they can be widely dispersed by local currents. As a result of the passage of the trawl rig across the seabed, shear strength of the sediment surface showed no significant increase, suggesting that bed armoring is not taking place and the trawled areas will not show an increase in critical shear stress. 相似文献
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19.
Progress in Scatterometer Application 总被引:10,自引:0,他引:10
W. Timothy Liu 《Journal of Oceanography》2002,58(1):121-136
Progress in the scientific application of space-based scatterometer data over the past two decades is reviewed. There has
been continuous improvement in coverage, resolution, and accuracy. Besides the traditional applications in weather and ocean-atmosphere
interaction, which are based on ocean surface wind vectors, emerging applications over land and ice are also described. Future
missions and new technology are introduced.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
Timothy R. Parsons 《Journal of Oceanography》1988,44(2):94-101
It is a great honour to be awarded the Oceanographical Society of Japan Prize for 1988 and to be provided with this opportunity
to review our work on trophic relations in the pelagic environment of the sea. Many Japanese colleagues have participated
in Canada on our experiments. These persons include Drs. H. Seki, M. Takahashi, A. Hattori, T. Ikeda, I. Koike, M. Ohtsu,
S. Ichimura, K. Iseki, E. Matsumoto, N. Handa, Y. Maita, and others without whom our work on marine ecosystems would have
assumed much less importance. In addition, the visit of Professor M. Uda to Nanaimo in 1959, and his lectures on fisheries
oceanography, have always been an inspiration to me in the practical application of oceanography.
For me, work on trophodynamic relationships grew out of my early association with Dr. J.D.H. Strickland who initiated some
ecosystem studies using large plastic bags in the 1960s (Strickland and Terhune, 1961; Strickland, 1967). The CEPEX program
(e.g. Parsons, 1978), which was started about a decade later, gave us the first real opportunity to break away from laboratory
studies, where only species which generally grew best were studied, and to perform studies under near natural conditions on
multiorganism communities. The purpose of this program was to provide some answers to practical problems as well as to gain
a fundamental understanding of biological oceanographic processes. This program was started at a time when a large number
of stories were circulating (e.g. Heyerdahl, 1975) that man was about to kill life in the oceans through pollution. In a practical sense what I believe that
the CEPEX program showed was that the oceans were much more resilient than had been supposed. The effect of many kinds of
pollutants tested during this program was to change the course of ecosystem interactions but not to cause the elimination
of life. The scientific value of these experiments went much further in giving us time series data about how the physical/chemical
environment interacts with different trophic levels. For the first time, the biological oceanographer was liberated from the
hopeless entanglement of time and space in the sea, and it was now possible to follow population dynamics of planktonic organisms
(Mullin, 1982).
Presented at the annual meeting, Tokyo, 4 April 1988. 相似文献