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Emerging Tools for Continuous Nutrient Monitoring Networks: Sensors Advancing Science and Water Resources Protection 下载免费PDF全文
Brian A. Pellerin Beth A. Stauffer Dwane A. Young Daniel J. Sullivan Suzanne B. Bricker Mark R. Walbridge Gerard A. Clyde Jr. Denice M. Shaw 《Journal of the American Water Resources Association》2016,52(4):993-1008
Sensors and enabling technologies are becoming increasingly important tools for water quality monitoring and associated water resource management decisions. In particular, nutrient sensors are of interest because of the well‐known adverse effects of nutrient enrichment on coastal hypoxia, harmful algal blooms, and impacts to human health. Accurate and timely information on nutrient concentrations and loads is integral to strategies designed to minimize risk to humans and manage the underlying drivers of water quality impairment. Using nitrate sensors as the primary example, we highlight the types of applications in freshwater and coastal environments that are likely to benefit from continuous, real‐time nutrient data. The concurrent emergence of new tools to integrate, manage, and share large datasets is critical to the successful use of nutrient sensors and has made it possible for the field of continuous monitoring to rapidly move forward. We highlight several near‐term opportunities for federal agencies, as well as the broader scientific and management community, that will help accelerate sensor development, build and leverage sites within a national network, and develop open data standards and data management protocols that are key to realizing the benefits of a large‐scale, integrated monitoring network. Investing in these opportunities will provide new information to guide management and policies designed to protect and restore our nation's water resources. 相似文献
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Assessment of Eutrophication in Estuaries: Pressure–State–Response and Nitrogen Source Apportionment 总被引:1,自引:0,他引:1
Whitall D Bricker S Ferreira J Nobre AM Simas T Silva M 《Environmental management》2007,40(4):678-690
A eutrophication assessment method was developed as part of the National Estuarine Eutrophication Assessment (NEEA) Program.
The program is designed to improve monitoring and assessment of eutrophication in the estuaries and coastal bays of the United
States with the intent to guide management plans and develop analytical and research models and tools for managers. These
tools will help guide and improve management success for estuaries and coastal resources. The assessment method, a Pressure-State-Response
approach, uses a simple model to determine Pressure and statistical criteria for indicator variables (where applicable) to
determine State. The Response determination is mostly heuristic, although research models are being developed to improve that
component. The three components are determined individually and then combined into a single rating. Application to several
systems in the European Union (E.U.), specifically in Portugal, shows that the method is transferable, and thus is useful
for development of management measures in both the Unites States and E.U. This approach identifies and quantifies the key
anthropogenic nutrient input sources to estuaries so that management measures can target inputs for maximum effect. Because
nitrogen is often the limiting nutrient in estuarine systems, examples of source identification and quantification for nitrogen
have been developed for 11 coastal watersheds on the U.S. east coast using the WATERSN model. In general, estuaries in the
Northeastern United States receive most of their nitrogen from human sewage, followed by atmospheric deposition. This is in
contrast to some watersheds in the Mid-Atlantic (Chesapeake Bay) and South Atlantic (Pamlico Sound), which receive most of
their nitrogen from agricultural runoff. Source identification is important for implementing effective management measures
that should be monitored for success using assessment methods, as described herein. For instance, these results suggest that
Northeastern estuaries would likely benefit most from improved sewage treatment, where as the Mid and South Atlantic systems
would benefit most from agricultural runoff reductions. 相似文献
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We carried out a field study of the plume discharged by a near-shore wastewater outfall near the Akashi Strait, Japan. Using
an Acoustic Doppler Current Profiler and a tow-body CTD, we measured the near-surface salinity and temperature fields in the
region throughout an M2 tidal cycle. We filtered the data in T–S space to remove water masses other than the wastewater, and then used the adiabatic
mixing assumption to calculate the concentration of wastewater in the far field of this plume. Averaging the T–S fields of
repeated surveys over a time period during which the tidal regime did not change substantially, allowed comparison of the
time-averaged plume with the analytical solution for a plume diffusing in both the horizontal and vertical dimensions. The
resulting vertical turbulent diffusion coefficients agreed well with those resulting from Thorpe scales determined via a vertically-profiling
CTD, as well as with the canonical value for open channel flow of D
z
= 0.067hu
*. The corresponding horizontal turbulent diffusion coefficients, however, were two orders of magnitude larger than those typically
observed in straight channels, and an order of magnitude larger than those observed in meandering rivers. This is likely a
result of enhanced horizontal mixing due to barotropic eddies generated by the interaction of strong tidal flow with headlands
and levees, as well as due to the time-varying nature of tidal flow, and baroclinic spreading of the buoyant wastewater plume. 相似文献
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Reaction of CO2 with LiOH requires the presence of water in an amount sufficient to produce monohydrate thium hydroxide (LiOH · H2O) prior to or simultaneously with the CO2 reaction. For a given CO2 content in the air stream at any given temperature, there is a corresponding humidity of the feed stream which results in maximum CO2 absorption efficiency. Two commercially available LiOH granules with different porosities and water contents were studied. The combined effects of temperature and humidity on CO2 absorption patterns and CO2 absorption capacities were observed. Results showed that temperature and water content of the air stream did change the CO2 absorption pattern and the CO2 absorption capacity for LiOH absorbent.When the relative humidity in the air stream is below 14%, anhydrous LiOH has a higher CO2 absorption capacity at higher temperatures. However, above 40% relative, lower temperatures are favored. Partially hydrated LiOH granules have a higher CO2 absorptions capacity at lower temperatures at all relative humidities in the air stream except 14%. 相似文献
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We carried out a field study of a small river plume emptying into Osaka Bay near the Akashi Strait in western Japan, to understand
the fate of its urban-runoff-laden waters. As the river is weak compared to tidal currents, we find that the behavior of the
plume is strongly influenced by phasing between tidal stage and currents (a westward-traveling progressive tidal wave). When
the tidal stage rises, sea water floods up the river, and concentrated river effluent cannot be seen in Osaka Bay. During
most of the river’s ebb, a topographic eddy transports river effluent towards the energetic Akashi Strait, while strong vertical
shear in the tidal flow mixes the effluent with seawater. However, there is a short interval of time during which the direction
of tidal flow in the Strait changes direction and the magnitude of the current is weak. At this time, shear is weak enough
to allow a stratified plume of concentrated river water to form, and this plume is driven offshore, and into Osaka Bay, by
baroclinic circulation. A sewage outfall, which is located very close to the river mouth, is subjected to these same conditions
and therefore exhibits similar behavior. Understanding the relation between tidal phase and plume behavior will be useful
to Kobe City, as well as other cities in a similar environment, for minimizing the environmental effects of their wastewater
and non-point-source runoff. 相似文献
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Loss of seeds to consumers is common in plant communities, but the degree to which these losses influence plant abundance or population growth is often unclear. This is particularly the case for postdispersal seed predation by rodents, as most studies of rodent seed predation have focused on the sources of spatiotemporal variation in seed loss but not quantified the population consequences of this loss. In previous work we showed that seed predation by deer mice (Peromyscus maniculatus) substantially reduced seedling recruitment and establishment of Lithospermum ruderale (Boraginaceae), a long-lived perennial forb. To shed light on how rodent seed predation and the near-term effects on plant recruitment might influence longer-term patterns of L. ruderale population growth, we combined experimental results with demographic data in stage-based population models. Model outputs revealed that rodent seed predation had a significant impact on L. ruderale population growth rate (lambda). With the removal of postdispersal seed predation, the projected population growth rates increased between 0.06 and 0.12, depending on site (mean deltalambda across sites = 0.08). Seed predation shifted the projected stable stage distribution of populations from one with a high proportion of young plants to one in which larger adult size classes dominate. Elasticities of vital rates also changed, with germination and growth of seedlings and young plants becoming more important with the removal of seed predation. Simulations varying the magnitude of seed predation pressure while holding other vital rates constant showed that seed predation could lower lambda even if only 40% of available seeds were consumed. These results demonstrate that rodent granivory can be a potent force limiting the abundance of a long-lived perennial forb. 相似文献
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Application and sensitivity testing of a eutrophication assessment method on coastal systems in the United States and European Union 总被引:5,自引:0,他引:5
The Assessment of Estuarine Trophic Status (ASSETS) screening model has been extended to allow its application to both estuarine and coastal systems. The model, which combines elements of pressure, state and response, was tested on four systems: Maryland Coastal Bays and Long Island Sound in the United States and The Firth of Clyde (Scotland) and Tagus Estuary (Portugal) in the European Union. The overall scores were: Maryland Coastal Bays: Bad; Firth of Clyde: Poor; Tagus Estuary: Good. Long Island Sound was modelled along a timeline, using 1991 data (score: Bad) and 2002 data (score: Moderate). The improvement registered for Long Island Sound is a consequence of the reduction in nutrient loading, and the ASSETS score changed accordingly. The two main areas where developments are needed are (a) In the definition of type-specific ranges for eutrophication parameters, due to the recognition that natural or pristine conditions may vary widely, and the use of a uniform set of thresholds artificially penalizes some systems and potentially leads to misclassification; (b) In the definition and quantification of measures which will result in an improved state through a change in pressures, as well as in the definition of appropriate metrics through which response may be assessed. One possibility is the use of detailed research models where different response scenarios potentially produce changes in pressure and state. These outputs may be used to drive screening models and analyze the suitability of candidate metrics for evaluating management options. 相似文献
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