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141.
Bruno Takahashi Kanni Huang Frederick Fico David Poulson 《Environmental Communication: A Journal of Nature and Culture》2017,11(1):106-121
This study focuses on the use of science sources as experts in news stories about climate change coverage in the Great Lakes region of the US and Canada. We examine, using the hierarchy of influences model, whether the use of scientific sources in climate change coverage may be related to factors such as geographic location, reporting frequency, and authorship, in the prestige press as well as regional and local media. The study found that as many or more non-scientists than scientists are selected as sources regardless of geographic location, reporting frequency, or authorship. However, the study also found that the more stories reporters produce on this topic, the more likely their stories are to use and give prominence to science sources. In addition, the articles included few denier sources, but denier views are more likely to appear in a more prominent location in the articles than supporters when stories are framed as conflict over global warming. These results highlight the need for additional research examining the expertise of climate scientists in news stories to better understand news decision-making in the context of complex scientific reporting. 相似文献
142.
Hemlock Woolly Adelgid (Adelges tsugae) is spreading across forests in eastern North America, causing mortality of eastern hemlock (Tsuga canadensis [L.] Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.). The loss of hemlock from riparian forests in Great Smoky Mountains National Park (GSMNP) may result in significant
physical, chemical, and biological alterations to stream environments. To assess the influence of riparian hemlock stands
on stream conditions and estimate possible impacts from hemlock loss in GSMNP, we paired hardwood- and hemlock-dominated streams
to examine differences in water temperature, nitrate concentrations, pH, discharge, and available photosynthetic light. We
used a Geographic Information System (GIS) to identify stream pairs that were similar in topography, geology, land use, and
disturbance history in order to isolate forest type as a variable. Differences between hemlock- and hardwood-dominated streams
could not be explained by dominant forest type alone as forest type yields no consistent signal on measured conditions of
headwater streams in GSMNP. The variability in the results indicate that other landscape variables, such as the influence
of understory Rhododendron species, may exert more control on stream conditions than canopy composition. The results of this study suggest that the
replacement of hemlock overstory with hardwood species will have minimal impact on long-term stream conditions, however disturbance
during the transition is likely to have significant impacts. Management of riparian forests undergoing hemlock decline should,
therefore, focus on facilitating a faster transition to hardwood-dominated stands to minimize long-term effects on water quality. 相似文献
143.
Wendy A. Kellogg 《Journal of Environmental Planning and Management》2009,52(4):549-570
This paper describes the collaborative planning process for a new landscape planning programme in Ohio that seeks to influence land urbanisation patterns through joint local land use decision making on a watershed basis. The programme was developed through a collaborative process by a state agency-appointed task force that included agency staff and a wide range of stakeholders. The paper describes the process in terms of the collaborative mechanisms, the participants, the programmatic outputs, and the social and organisational outcomes that set the foundation for enhanced watershed quality through better land use decision-making practices. Key collaborations formed during the process were inter-agency collaborations, a non-profit organisation that partnered with the agencies, and that of state agencies with local governments to develop watershed-based land use plans. A most critical outcome was creation of a learning community, through an exploratory research process that used multiple methods of data gathering and consensus-building deliberation. The paper is based on a review of published documents and plans, meeting minutes, participant observation of committee and workgroup meetings and interactive research. 相似文献
144.
Li A Rockne KJ Sturchio N Song W Ford JC Wei H 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):141-147
A region-wide data analysis on polychlorinated biphenyls (PCBs) in the sediment of the Great Lakes reveals a total accumulation of approximately 300 ± 50 tonnes, representing a >30% reduction from the 1980s. Evidence of in situ degradation of sediment PCB was found, with estimated t1/2 of 11 and 17 years, at two open water locations in Lake Ontario. The relative abundance of heavy homologs as well as para-chlorines decreases with increasing depth, while the opposite is true for medium and light homologs and ortho-chlorines. In Lake Michigan, the vertical pattern features enrichment of heavier congeners and reduction of ortho-chlorines in deeper sediment layers, opposite to the trend in Lake Ontario. PCBs decrease log-linearly with increasing latitude and longitude. Air deposition of PCBs to lake sediment decreases at about 0.077 ng cm−2 yr−1 per degree latitude (N) for the geographic region extending from the Great Lakes to within the Arctic Circle. 相似文献
145.
Investigations of place have often focused on either place meaning (utilizing interpretive designs) or place attachment (using quantitative measures). Rarely have researchers explored the association between place meaning and place attachment. Hence, this investigation was designed to explore how individuals' attachment to a natural environment is reflected in their depictions of why the resource is meaningful. 相似文献
146.
Bartrons M Grimalt JO Catalan J 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1816-1822
The present study shows the occurrence of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes. 相似文献
147.
Leat EH Bourgeon S Borgå K Strøm H Hanssen SA Gabrielsen GW Petersen A Olafsdottir K Magnusdottir E Fisk AT Ellis S Bustnes JO Furness RW 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1222-1228
Concentrations of POPs in Great skua eggs from Shetland are among the highest in North Atlantic seabirds, with up to 11,600 μg/kg (ww) DDE and up to 17,900 μg/kg ww ∑PCB. Concentrations of legacy POPs were significantly lower in 2008 than 1980. Decreases were greatest for least persistent compounds. Median ∑PBDEs increased from 99 μg/kg ww in 1980 to 173 μg/kg ww in 2008. There were changes in Great skua breeding season diet, with more adult Herring and Mackerel and less Sandeel. These changes increase exposure to POPs, since Herring and Mackerel accumulate more POPs than Sandeels. In both years, eggs with higher δ15N had higher POP concentrations. In 1980, birds feeding more on demersal discard fish from trawl fisheries and less on Sandeels, had higher POP levels in eggs. In 2008, individuals feeding more on Herring and Mackerel, and less on discards, had higher POP levels in eggs. 相似文献
148.
Ecotechnological methods have been employed by developed countries like the United States of America, Europe, Australia and
Japan in the restoration of their degraded freshwater ecosystems. These methods according to literature sources, in many cases
have produced the desired results in these countries where they have been implemented. This article is aimed at providing
an overview on aspects of available ecotechnological methods employed in the reduction of eutrophication and acidification
and in Lake Ecosystem restoration in general. Ecotechnological methods offer great opportunities for developing countries
with tropical or subtropical climates due to their cost-effectiveness. The efficacy and potential limitations of the various
methods in their respective restorative approach is also reported in this article. 相似文献
149.
Many government agencies and other organizations sample natural alpine and subalpine surface waters using varying protocols
for sample storage and filtration. Simplification of protocols would be beneficial if it could be shown that sample quality
is unaffected. In this study, samples collected from low ionic strength waters in alpine and subalpine lake inlets and outlets
in the western United States were used to evaluate (1) effects of refrigerated storage time on the chemistry of unfiltered
samples, and (2) differences in sample filtration protocols. No analytes exhibited significant changes when stored less than
48 h. Six analytes (pH, sodium, ammonium, potassium, chloride, sulfate) exhibited statistically significant (but small) changes
when storage time exceeded 48 h. Two analytes (calcium, nitrate) were significantly higher when samples were field filtered
than when filtered in the laboratory, but the differences were also small. For waters similar to those in this test, unfiltered
refrigerated samples may be stored up to 48 h without compromising sample quality. The small differences between field and
lab filtration do not justify the expense, training, and contamination risk of field filtration. 相似文献
150.
Climate change is likely to impact terrestrial and aquatic ecosystems via numerous physical and biological mechanisms. This study outlines a framework for projecting potential impacts of climate change on lakes using linked environmental models. Impacts of climate drivers on catchment hydrology and thermal balance in Onondaga Lake (New York State) are simulated using mechanistic models HSPF and UFILS4. Outputs from these models are fed into a lake ecosystem model, developed in AQUATOX. Watershed simulations project increases in the magnitude of peak flows and consequent increases in catchment nutrient export as the magnitude of extreme precipitation events increases. This occurs concurrently with a decrease in annual stream discharge as a result of increased evapotranspiration. Simulated lake water temperatures increase by as much as 5 °C during the 2040-2069 time period, accompanied by a prolonging of the duration of summer stratification. Projected changes include shifts in the timing of nutrient cycling between lake sediments and water column. Plankton taxa projected to thrive under climate change include green algae and Bosmina longirostris. Responses for species at higher trophic levels are mixed. Benthic macroinvertebrates may either prosper (zebra mussels) or decline (chironomids), while fish (e.g., gizzard shad) exhibit high seasonal variability without any clear trend. 相似文献