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541.
Arthur H. Johnson 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1049-1054
Red spruce have died in abnormal numbers in the high elevation forests of New York and New England during the past two decades while spruce in the southern Appalachians remain healthy. Investigations of insect damage, fungal pathogens, successional dynamics, competitive status, climate and weather patterns and possible pollutant effects indicate that the decline was triggered by abiotic stress during the dry years of the 1960s. Tree response, as recorded in the pattern of annual rings, and the wide range of soil conditions in which spruce are declining, suggest drought or dry summers as key factors. Hypotheses regarding the role of acid deposition induced stress have been offered, but at present there is not evidence which clearly links acid deposition to spruce decline. Indirect effects of acid deposition on soils, direct effects of acid deposition on foliage, and interactions of acid deposition and drought stress are possible but unproven pathways by which acid deposition could be involved. 相似文献
542.
Johnson AC Keller V Williams RJ Young A 《Environmental pollution (Barking, Essex : 1987)》2007,146(1):155-165
An existing GIS hydrology water quality model, LF2000-WQX, was applied to predict the concentrations of the pharmaceuticals diclofenac and propranalol in catchments. As a practical exercise the predominantly rural Tamar (UK) catchment was chosen. Consumption, excretion, and fate data were used to estimate the pharmaceutical input load for the model. The predicted concentrations throughout most of the catchment were 1 ng/L or less under low flow (90th percentile) conditions. However, at a few locations, downstream of small sewage treatment plants, concentrations above 25 ng/L were predicted. This exercise shows that it is relatively straightforward to predict the concentrations of new and emerging organic microcontaminants in real catchments using existing GIS hydrology water quality models. Further testing will be required to establish their accuracy. 相似文献
543.
The introduction of anthropogenic sounds into the marine environment can impact some marine mammals. Impacts can be greatly
reduced if appropriate mitigation measures and monitoring are implemented. This paper concerns such measures undertaken by
Exxon Neftegas Limited, as operator of the Sakhalin-1 Consortium, during the Odoptu 3-D seismic survey conducted during 17
August–9 September 2001. The key environmental issue was protection of the critically endangered western gray whale (Eschrichtius robustus), which feeds in summer and fall primarily in the Piltun feeding area off northeast Sakhalin Island. Existing mitigation
and monitoring practices for seismic surveys in other jurisdictions were evaluated to identify best practices for reducing
impacts on feeding activity by western gray whales. Two buffer zones were established to protect whales from physical injury
or undue disturbance during feeding. A 1 km buffer protected all whales from exposure to levels of sound energy potentially
capable of producing physical injury. A 4–5 km buffer was established to avoid displacing western gray whales from feeding
areas. Trained Marine Mammal Observers (MMOs) on the seismic ship Nordic Explorer had the authority to shut down the air guns if whales were sighted within these buffers.
Additional mitigation measures were also incorporated: Temporal mitigation was provided by rescheduling the program from June–August
to August–September to avoid interference with spring arrival of migrating gray whales. The survey area was reduced by 19%
to avoid certain waters <20 m deep where feeding whales concentrated and where seismic acquisition was a lower priority. The
number of air guns and total volume of the air guns were reduced by about half (from 28 to 14 air guns and from 3,390 in3 to 1,640 in3) relative to initial plans. “Ramp-up” (=“soft-start”) procedures were implemented.
Monitoring activities were conducted as needed to implement some mitigation measures, and to assess residual impacts. Aerial
and vessel-based surveys determined the distribution of whales before, during and after the seismic survey. Daily aerial reconnaissance
helped verify whale-free areas and select the sequence of seismic lines to be surveyed. A scout vessel with MMOs aboard was
positioned 4 km shoreward of the active seismic vessel to provide better visual coverage of the 4–5 km buffer and to help
define the inshore edge of the 4–5 km buffer. A second scout vessel remained near the seismic vessel. Shore-based observers
determined whale numbers, distribution, and behavior during and after the seismic survey. Acoustic monitoring documented received
sound levels near and in the main whale feeding area.
Statistical analyses of aerial survey data indicated that about 5–10 gray whales moved away from waters near (inshore of)
the seismic survey during seismic operations. They shifted into the core gray whale feeding area farther south, and the proportion
of gray whales observed feeding did not change over the study period.
Five shutdowns of the air guns were invoked for gray whales seen within or near the buffer. A previously unknown gray whale
feeding area (the Offshore feeding area) was discovered south and offshore from the nearshore Piltun feeding area. The Offshore
area has subsequently been shown to be used by feeding gray whales during several years when no anthropogenic activity occurred
near the Piltun feeding area.
Shore-based counts indicated that whales continued to feed inshore of the Odoptu block throughout the seismic survey, with
no significant correlation between gray whale abundance and seismic activity. Average values of most behavioral parameters
were similar to those without seismic surveys. Univariate analysis showed no correlation between seismic sound levels and
any behavioral parameter. Multiple regression analyses indicated that, after allowance for environmental covariates, 5 of
11 behavioral parameters were statistically correlated with estimated seismic survey-related variables; 6 of 11 behavioral
parameters were not statistically correlated with seismic survey-related variables. Behavioral parameters that were correlated
with seismic variables were transient and within the range of variation attributable to environmental effects.
Acoustic monitoring determined that the 4–5 km buffer zone, in conjunction with reduction of the air gun array to 14 guns
and 1,640 in3, was effective in limiting sound exposure. Within the Piltun feeding area, these mitigation measures were designed to insure
that western gray whales were not exposed to received levels exceeding the 163 dB re 1 μPa (rms) threshold.
This was among the most complex and intensive mitigation programs ever conducted for any marine mammal. It provided valuable
new information about underwater sounds and gray whale responses during a nearshore seismic program that will be useful in
planning future work. Overall, the efforts in 2001 were successful in reducing impacts to levels tolerable by western gray
whales. Research in 2002–2005 suggested no biologically significant or population-level impacts of the 2001 seismic survey.
M. W. Newcomer is deceased. 相似文献
544.
Kahl JS Nelson SJ Fernandez I Haines T Norton S Wiersma GB Jacobson G Amirbahman A Johnson K Schauffler M Rustad L Tonnessen K Lent R Bank M Elvir J Eckhoff J Caron H Ruck P Parker J Campbell J Manski D Breen R Sheehan K Grygo A 《Environmental monitoring and assessment》2007,126(1-3):9-25
This paper is an overview of this special issue devoted to watershed research in Acadia National Park (Acadia NP). The papers
address components of an integrated research program on two upland watersheds at Acadia NP, USA (44° 20′ N latitude; 68° 15′
E longitude). These watersheds were instrumented in 1998 to provide a long-term foundation for regional ecological and watershed
research. The research was initiated as part of EPA/NPS PRIMENet (Park Research and Intensive Monitoring of Ecosystems Network),
a system of UV-monitoring stations and long-term watershed research sites located in US national parks. The initial goals
at Acadia NP were to address research questions about mercury, acid rain, and nitrogen saturation developed from prior research.
The project design was based on natural differences in forests and soils induced by an intense wildfire in one watershed in
1947. There is no evidence of fire in the reference watershed for several hundred years. We are testing hypotheses about controls
on surface water chemistry, and bioavailability of contaminants in the contrasting watersheds. The unburned 47-ha Hadlock
Brook watershed is 70% spruce-fir mature conifer forest. In contrast, burned 32-ha Cadillac Brook watershed, 4 km northeast
of the Hadlock watershed, is 20% regenerating mixed northern hardwoods and 60% shrub/rocky balds. Differences in atmospheric
deposition are controlled primarily by forest stand composition and age. The watersheds are gauged and have water chemistry
stations at 122 m (Cadillac) and 137 m (Hadlock); watershed maximum elevations are 468 and 380 m, respectively. The stream
water chemistry patterns reflect, in part, the legacy of the intense fire, which, in turn, controls differences in forest
vegetation and soil characteristics. These factors result in higher nitrogen and mercury flux from the unburned watershed,
reflecting differences in atmospheric deposition, contrasting ecosystem pools of nitrogen and mercury, and inferred differences
in internal cycling and bioavailabilty. 相似文献
545.
Schauffler M Nelson SJ Kahl JS Jacobson GL Haines TA Patterson WA Johnson KB 《Environmental monitoring and assessment》2007,126(1-3):39-53
Paleoecological reconstructions of forest stand histories for two upland watersheds at Acadia National Park in Maine were
completed to support related watershed chemistry studies. The project hypothesis was that forest type and fire history influence
long-term cycling and storage of atmospheric mercury and nitrogen within watersheds. The reconstructions document differences
in major vegetation composition and disturbance between the burned and unburned watersheds during the past several centuries.
Pollen and charcoal stratigraphies from organic sediment accumulations in forested wet depressions indicate that the present
experimental design of contrasting disturbance and forest histories has persisted during recent centuries. The unburned watershed
has been dominated by spruce (Picea rubens) and fir (Abies balsamea) for 500 years or more and has not recently burned or been substantially cleared. The burned watershed is dominated by a
heterogeneous forest of patchy hardwood, mixed wood, and softwood stands. A large portion of this watershed burned severely
in 1947 and probably more than once in the 1800s, and has supported heterogeneous successional forests for 200 years or longer.
Overall, these results support the underlying premise that the experimental design of this watershed research can be used
to infer landscape controls on biogeochemical processes. 相似文献
546.
Economic Development and Conservation of Biological and Cultural Diversity in Yunnan Province, China
Rey C. Stendell Richard L. Johnson John P. Mosesso Xia Zhang 《Environment, Development and Sustainability》2000,2(3-4):333-345
Chinese and American scientists are co-operating to develop concepts, strategies, agreements, and proposals in support of an economic development and sustainable ecosystems project in Yunnan Province, People's Republic of China. Yunnan's Provincial Government has initiated a major programme to develop and further utilise its biological resources to help improve economic conditions for its citizens. They are co-operating with the US Geological Survey (USGS) on evaluation and management of biological resources so economic development will be compatible with sustainable ecological systems. Scientists from the USGS and co-operating universities will provide expertise on synthesising biological data, conducting a Gap Analysis for the Province, evaluating innovative economic opportunities, and designing an effective education, training, and outreach programme. 相似文献
547.
Cynthia Armendáriz-Arnez Rufus D. Edwards Michael Johnson Irma A. Rosas F. Espinosa Omar R. Masera 《Atmospheric environment (Oxford, England : 1994)》2010,44(24):2881-2886
Particulate pollution has been clearly linked with adverse health impacts from open fire cookstoves, and indoor air concentrations are frequently used as a proxy for exposures in health studies. Implicit are the assumptions that the size distributions for the open fire and improved stove are not significantly different, and that the relationship between indoor concentrations and personal exposures is the same between stoves. To evaluate the impact of these assumptions size distributions of particulate matter in indoor air were measured with the Sioutas cascade impactor in homes using open fires and improved Patsari stoves in a rural Purepecha community in Michoacan, Mexico. On average indoor concentrations of particles less than 0.25 μm were 72% reduced in homes with improved Patsari stoves, reflecting a reduced contribution of this size fraction to PM2.5 mass concentrations from 68% to 48%. As a result the mass median diameter of indoor PM2.5 particulate matter was increased by 29% with the Patsari improved stove compared to the open fire (from 0.42 μm to 0.59 μm, respectively). Personal PM2.5 exposure concentrations for women in homes using open fires were approximately 61% of indoor concentration levels (156 μg m?3 and 257 μg m?3 respectively). In contrast personal exposure concentrations were 77% times indoor air concentration levels for women in homes using improved Patsari stoves (78 μg m?3and 101 μg m?3 respectively). Thus, if indoor air concentrations are used in health and epidemiologic studies significant bias may result if the shift in size distribution and the change in relationship between indoor air concentrations and personal exposure concentrations are not accounted for between different stove types. 相似文献
548.
549.
We present a comprehensive set of Se concentration and isotope ratio data collected over a 3-yr period from dissolved, sediment-hosted, and organically bound Se in a Se-contaminated lake and littoral wetland. Median isotope ratios of these various pools of Se spanned a narrow isotopic range (delta80/76Se(SRM-3149)) = 1.14-2.40 per thousand). Selenium (VI) reduction in the sediments is an important process in this system, but its isotopic impact is muted by the lack of direct contact between surface waters and reduction sites within sediments. This indicates that using Se isotope data as an indicator of microbial or abiotic Se oxyanion reduction is not effective in this or other similar systems. Isotopic data suggest that most Se(IV) in the lake originates from oxidation of organically bound Se rather than directly through Se(VI) reduction. Mobilization of Se(VI) from bedrock involves only a slight isotopic shift. Temporally constant isotopic differences observed in Se(VI) from two catchment areas suggest the potential for tracing Se(VI) from different source areas. Phytoplankton isotope ratios are close to those of the water, with a small depletion in heavy isotopes (0.56 per thousand). Fish tissues nearly match the phytoplankton, being only slightly depleted in the heavier isotopes. This suggests the potential for Se isotopes as migration indicators. Volatile, presumably methylated Se was isotopically very close to median values for phytoplankton and macrophytes, indicating a lack of isotopic fractionation during methylation. 相似文献
550.
John H. Rodgers Jr. Brenda M. Johnson West M. Bishop 《Journal of the American Water Resources Association》2010,46(1):153-160
Rodgers, John H., Jr., Brenda M. Johnson, and West M. Bishop, 2010. Comparison of Three Algaecides for Controlling the Density of Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):153-160. DOI: 10.1111/j.1752-1688.2009.00399.x Abstract: Prymnesium parvum has become more prevalent in water resources of the southern United States. As the potential impacts of P. parvum are relatively well known, especially its capability to severely affect fish, managers have sought efficacious, environmentally sound, and socially acceptable strategies for mitigating this noxious species. Laboratory testing was used to identify an effective algaecide for control of P. parvum from Texas, Arizona, Florida, North Carolina, and South Carolina. Cutrine®-Plus at 0.2 mg Cu/l significantly decreased the density of P. parvum in samples from all of these locations. Both copper sulfate and Phycomycin® were less effective for controlling the population growth of P. parvum. The predicted response from the laboratory study was confirmed in the field at the Arizona site. Strategic use of Cutrine®-Plus in larger water resources could provide toxin-free refugia to allow some fish to survive and repopulate the water resource when the golden alga infestation abates. 相似文献