222 research outputs found
Distribution of the Fishes of The Great Smoky Mountains National Park
Over 200 collections of fishes have been made within the boundaries of the Great Smoky Mountains National Park, revealing a Park ichthyofauna of 74 native and 5 introduced fish species. Abrams Creek, containing the most diverse ichthyofauna in the park, currently contains only 35 of its historical 67 fish species. This loss of species resulted from intentional poisoning of eh creek to improve habitat for rainbow trout and impoundment of the lowest 2.6 miles by Chilhowee Reservoir.
Abrams Creek also contains a very unusual ichthyofauna in its upper portion. Several species found above its 25-foot waterfall have not been found below it, and some are rare elsewhere in the Little Tennessee River system. A possible drainage history, supported by both ichthyological and geological data is theorized. Outlets for some of the streams now in the upper Abrams Creek system may have existed toward Little River and Parsons Branch or Tabcat Creek.
Possible environmental problems which might be faced by the Park\u27s fishes are discussed. Although the streams in the Park are not subjected to problems such as waste water treatment or agricultural runoff, they are effected by such problems as acid rain and the possibility of global warming
Carbon Capture and Storage
Emissions of carbon dioxide, the most important long-lived anthropogenic greenhouse gas, can be reduced
by Carbon Capture and Storage (CCS). CCS involves the integration of four elements: CO 2 capture, compression of the CO2 from a gas to a liquid or a denser gas, transportation of pressurized CO 2 from the point of capture to the storage location, and isolation from the atmosphere by storage in deep underground rock formations. Considering full life-cycle emissions, CCS technology can reduce 65–85% of CO2 emissions from fossil fuel combustion from stationary sources, although greater reductions may be possible if low emission technologies are applied to activities beyond the plant boundary, such as fuel transportation.
CCS is applicable to many stationary CO2 sources, including the power generation, refining, building
materials, and the industrial sector. The recent emphasis on the use of CCS primarily to reduce emissions from coal-fired electricity production is too narrow a vision for CCS.
Interest in CCS is growing rapidly around the world. Over the past decade there has been a remarkable increase in interest and investment in CCS. Whereas a decade ago, there was only one operating CCS project and little industry or government investment in R&D, and no financial incentives to promote CCS. In 2010, numerous projects of various sizes are active, including at least five large-scale full CCS projects. In 2015, it is expected that 15 large-scale, full-chain CCS projects will be running. Governments and industry have committed over USD 26 billion for R&D, scale-up and deployment.
The technology for CCS is available today, but significant improvements are needed to support widespread
deployment. Technology advances are needed primarily to reduce the cost of capture and increase confidence in storage security. Demonstration projects are needed to address issues of process integration between CO2 capture and product generation, for instance in power, cement and steel production, obtain cost and performance data, and for industry where capture is more mature to gain needed operational experience. Large-scale storage projects in saline aquifers are needed to address issues of site characterization and site selection, capacity assessment, risk management and monitoring.
Successful experiences from five ongoing projects demonstrate that, at least on this limited scale, CCS can
be safe and effective for reducing emissions. Five commercial-scale CCS projects are operational today with over 35 million tonnes of CO2 captured and stored since 1996. Observations from commercial storage projects, commercial enhanced oil recovery projects, engineered and natural analogues as well as theoretical considerations, models, and laboratory experiments suggest that appropriately selected and managed geological storage reservoirs are very likely to retain nearly all the injected CO2 for very long times, more than long enough to provide benefits for the intended purpose of CCS.
Significant scale-up compared to existing CCS activities will be needed to achieve large reductions in CO2
emissions. A 5- to 10-fold scale-up in the size of individual projects is needed to capture and store emissions from a typical coal-fired power plant (500 to 1000 MW). A thousand fold scale-up in size of today’s CCS enterprise would be needed to reduce emissions by billions of tonnes per year (Gt/yr).
The technical potential of CCS on a global level is promising, but on a regional level is differentiated. The
primary technical limitation for CCS is storage capacity. Much more work needs to be done to realistically assess storage capacity on a worldwide, regional basis and sub-regional basis.
Worldwide storage capacity estimation is improving but more experience is needed. Estimates for oil and gas reservoirs are about 1000 GtCO2, saline aquifers are estimated to have a capacity ranging from about 4000 to 23,000 GtCO2. However, there is still considerable debate about how much storage capacity actually exists, particularly in saline aquifers. Research, geological assessments and, most importantly, commercial-scale demonstration projects will be needed to improve confidence in capacity estimates.
Costs and energy requirements for capture are high. Estimated costs for CCS vary widely, depending on the application (e.g. gas clean-up vs. electricity generation), the type of fuel, capture technology, and assumptions about the baseline technology. For example, with today’s technology, CCS would increase cost of generating electricity by 50–100%. In this case, capital costs and parasitic energy requirements of 15–30% are the major cost drivers. Research is underway to lower costs and energy requirements. Early demonstration projects are likely to cost more.
The combination of high cost and low or absent incentives for large-scale deployment are a major factor
limiting the widespread use of CCS. Due to high costs, CCS will not take place without strong incentives to limit CO2 emissions. Certainty about the policy and regulatory regimes will be crucial for obtaining access to capital to build these multi-billion dollar projects.
Environmental risks of CCS appear manageable, but regulations are needed. Regulation needs to ensure due diligence over the lifecycle of the project, but should, most importantly, also govern site selection, operating guidelines, monitoring and closure of a storage facility.
Experience so far has shown that local resistance to CO2 storage projects may appear and can lead to
cancellation of planned CCS projects. Inhabitants of the areas around geological storage sites often have concerns about the safety and effectiveness of CCS. More CCS projects are needed to establish a convincing safety record. Early engagement of communities in project design and site selection as well as credible communication can help ease resistance. Environmental organisations sometimes see CCS as a distraction from a sustainable energy future.
Social, economic, policy and political factors may limit deployment of CCS if not adequately addressed.
Critical issues include ownership of underground pore space (primarily an issue in the US); long-term liability and stewardship; GHG accounting approaches and ve rification; and regulatory oversight regimes. Governments and the private sector are making significant progress on all of these issues. Government support to lower barriers for early deployments is needed to encourage private sector adoption. Developing countries will need support for technology access, lowering the cost of CCS, developing workforce capacity and training regulators for permitting, monitoring and oversight.
CCS combined with biomass can lead to negative emissions . Such technologies are likely to be needed to achieve atmospheric stabilization of CO2 and may provide an additional incentive for CCS adoption
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Anodonta imbecillis copper sulfate reference toxicant/food test, Clinch River - Environmental Restoration Program (CR-ERP)
Reference toxicant testing using juvenile freshwater mussels was conducted as part of the CR-ERP biomonitoring study of Clinch River sediments to assess the sensitivity of test organisms and the overall performance of the test. Tests were conducted using moderately hard synthetic water spiked with known concentrations of copper as copper sulfate. Two different foods, phytoplankton and YCT-Selenastrum (YCT-S), were tested in side by side tests to compare food quality. Toxicity testing of copper sulfate reference toxicant was conducted from July 6-15, 1993. The organisms used for testing were juvenile fresh-water mussels (Anodonta imbecillis). Results from this test showed LC{sub 50} values of 0.97 and 0.84 mg Cu/L for phytoplankton and YCT-S, respectively. Previously obtained values for phytoplankton tests are 2.02 and 1.12 mg Cu/L. Too few tests have been conducted with copper as the toxicant to determine a normal range of values. Although significant reduction in growth, compared to the phytoplankton control, was seen in all treatments, including the YCT-S Control, the consequence of this observation has not been established. Ninety-day testing of juvenile mussels exhibited large variations in growth within treatment and replicate groups
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Anodonta imbecillis QA Test 1, Clinch River - Environmental Restoration Program (CR-ERP)
Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA and CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments to provide a quality assurance mechanism for test organism quality and overall performance of the test. In addition, testing included procedures comparing daily renewal versus non-renewal of test sediments. Testing of sediment samples collected July 15 from Poplar Creek Miles 6.0 and 5.1 was conducted from July 21-30, 1993. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Side by side testing of sediments with daily sediment renewal and no sediment renewal showed no differences between methods. This may be due to the absence of toxicity in both samples and may not reflect true differences between the two methods for toxic sediment
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Clinch River - Environmental Restoration Program (CR-ERP) study, Ambient water toxicity
Clinch River - Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of January 25-February 1, 1994, as described in the Statement of Work (SOW) document. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field Engineering personnel from Clinch River Mile 9.0, Poplar Creek Mile 1.0, and Poplar Creek Mile 2.9 on January 24, 26, and 28. Samples were partitioned (split) and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival or growth) to fathead minnows; however, toxicity to daphnids (significantly reduced reproduction) was demonstrated in undiluted samples from Poplar Creek Mile 1.0 in testing conducted by TVA based on hypothesis testing of data. Point estimation (IC{sub 25}) analysis of the data, however, showed no toxicity in PCM 1.0 samples
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Anodonta imbecillis QA Test 4, Clinch River - Environmental restoration program (CR-ERP)
Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected September 8 from Poplar Creek Miles 6.0 and 1.0 was conducted September 13-22, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments
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Anodonta imbecillis copper sulfate reference toxicant test, Clinch River - Environmental Restoration Program (CR-ERP)
Reference toxicant testing using juvenile freshwater mussels was conducted as part of the CR-ERP biomonitoring study of Clinch River sediments to assess the sensitivity of test organisms and the overall performance of the test. Tests were conducted using moderately hard synthetic water spiked with known concentrations of copper as copper sulfate. Toxicity testing of copper sulfate reference toxicant was conducted from May 12-21, 1993. The organisms used for testing were juvenile fresh-water mussels (Anodonta imbecillis). Results from this test showed an LC{sub 50} value of 1.12 mg Cu/L which is lower than the value of 2.02 mg Cu/L obtained in a previous test. Too few tests have been conducted with copper as the toxicant to determine a normal range of values
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Anodonta imbecillis QA Test 3, Clinch River - Environmental Restoration Program (CR-ERP)
Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected May 5 from Poplar Creek Miles 6.0 and 2.9 was conducted from May 10-19, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments
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Clinch River - Environmental Restoration Program (CR-ERP) pilot study, ambient water toxicity
Clinch River - Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a pilot study during the week of April 22-29, 1993, prior to initiation of CR-ERP Phase II Sampling and Analysis activities as described in the Statement of Work (SOW) document. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field Engineering personnel from Clinch River Mile 9.0 and Poplar Creek Kilometer 1.6 on April 21, 23, and 26. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival, growth, or reproduction) to either species in testing conducted by TVA
Highly Accurate, But Still Discriminatory
The study aims to identify whether algorithmic decision making leads to unfair (i.e., unequal) treatment of certain protected groups in the recruitment context. Firms increasingly implement algorithmic decision making to save costs and increase efficiency. Moreover, algorithmic decision making is considered to be fairer than human decisions due to social prejudices. Recent publications, however, imply that the fairness of algorithmic decision making is not necessarily given. Therefore, to investigate this further, highly accurate algorithms were used to analyze a pre-existing data set of 10,000 video clips of individuals in self-presentation settings. The analysis shows that the under-representation concerning gender and ethnicity in the training data set leads to an unpredictable overestimation and/or underestimation of the likelihood of inviting representatives of these groups to a job interview. Furthermore, algorithms replicate the existing inequalities in the data set. Firms have to be careful when implementing algorithmic video analysis during recruitment as biases occur if the underlying training data set is unbalanced
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