The isotope hydrology of the Muskoka River Watershed,Ontario, Canada     

April L. James  Emily Dusome  Tim Field  Huaxia Yao  Chris McConnell  Andy Beaton  Arghavan Tafvizi 《水文研究》2020,34(4):914-926

Stable isotope tracers of δ¹⁸O and δ²H are increasingly being applied in the study of water cycling in regional-scale watersheds in which human activities, like river regulation, are important influences. In 2015, δ¹⁸O and δ²H were integrated into a water quality survey in the Muskoka River Watershed with the aim to provide new regional-scale characterization of isotope hydrology in the 5,100-km² watershed located on the Canadian Shield in central Ontario, Canada. The forest dominated region includes ~78,000 ha of lakes, 42 water control structures, and 11 generating stations, categorized as “run of river.” Within the watershed, stable isotope tracers have long been integrated into hydrologic process studies of both headwater catchments and lakes. Here, monthly surveys of δ¹⁸O and δ²H in river flow were conducted in the watershed between April 2015 and November 2016 (173 surface water samples from 10 river stations). Temporal patterns of stable isotopes in river water reflect seasonal influences of snowmelt and summer-time evaporative fractionation. Spatial patterns, including differences observed during extreme flood levels experienced in the spring of 2016, reflect variation in source contributions to river flow (e.g., snowmelt or groundwater versus evaporatively enriched lake storage), suggesting more local influences (e.g., glacial outwash deposits). Evidence of combined influences of source mixing and evaporative fractionation could, in future, support application of tracer-enabled hydrological modelling, estimation of mean transit times and, as such, contribute to studies of water quality and water resources in the region.  相似文献   

Merging perspectives in the catchment sciences: the US–Japan Joint Seminar on catchment hydrology and forest biogeochemistry          下载免费PDF全文

Kevin J. McGuire  Stephen D. Sebestyen  Nobuhito Ohte  Emily M. Elliott  Takashi Gomi  Mark B. Green  Brian L. McGlynn  Naoko Tokuchi 《水文研究》2014,28(5):2878-2880

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Extratropical cyclones and the projected decline of winter Mediterranean precipitation in the CMIP5 models     

Giuseppe Zappa  Matthew K. Hawcroft  Len Shaffrey  Emily Black  David J. Brayshaw 《Climate Dynamics》2015,45(7-8):1727-1738

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Redacted in Nebraska: the noises of conspiracy around nuclear power problems     

John Eyles  Jana Fried  Emily Catherine Eyles 《GeoJournal》2014,79(3):329-342

This paper investigates a ‘small story’, the problems around the Fort Calhoun nuclear power plant (Nebraska) in the wet summer of 2011. Relying on materials from digital media, it presents the official and an alternative version of events. Utilizing a constructionist approach, it identifies the search for moral certainty, as well as the importance of blame and conspiracy theories, from which emerges the ‘big story’. Highlighting the important role of on-line media and digital communication, we document not only the official story but also an opposing version based on a coherent worldview emphasising the problems of big government, liberal views and denial of American individual rights—all framed as a conspiracy covering-up a threatening, human-made technology failure. We suggest why this worldview occurs, stressing a widespread emphasis on American values and history, ‘failed journalism’, public uncertainty, the complexity of nuclear technology, and the specific uses of digital communication.  相似文献   

Long-term biological effects of petroleum residues on fiddler crabs in salt marshes   总被引：1，自引：1，他引：0  

Culbertson JB  Valiela I  Peacock EE  Reddy CM  Carter A  VanderKruik R 《Marine pollution bulletin》2007,54(7):955-962

In September 1969, the Florida barge spilled 700,000L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor (Buzzards Bay, MA). Today the aboveground environment appears unaffected, but a substantial amount of moderately degraded petroleum still remains 8-20cm below the surface. The salt marsh fiddler crabs, Uca pugnax, burrow into the sediments at depths of 5-25cm, and are chronically exposed to the spilled oil. Behavioral studies conducted with U. pugnax from Wild Harbor and a control site, Great Sippewissett marsh, found that crabs exposed to the oil avoided burrowing into oiled layers, suffered delayed escape responses, lowered feeding rates, and achieved lower densities. The oil residues are therefore biologically active and affect U. pugnax populations. Our results add new knowledge about long-term consequences of spilled oil, a dimension that should be included when assessing oil-impacted areas and developing management plans designed to restore, rehabilitate, or replace impacted areas.  相似文献   

The preservation of fossil biomarkers during meteorite impact events: Experimental evidence from biomarker‐rich projectiles and target rocks     

John PARNELL  Stephen BOWDEN  Paula LINDGREN  Mark BURCHELL  Daniel MILNER  Mark PRICE  Emily C. BALDWIN  Ian A. CRAWFORD 《Meteoritics & planetary science》2010,45(8):1340-1358

Abstract– A Devonian siltstone from Orkney, Scotland, shows survival of biomarkers in high‐velocity impact experiments. The biomarkers were detected in ejecta fragments from experiments involving normal incidence of steel projectiles at 5–6 km s^?1, and in projectile fragments from impact experiments into sand and water at 2–5 km s^?1. The associated peak shock pressures were calculated to be in the range of 110–147 GPa for impacts of the steel projectiles into the siltstone target, and hydrocode simulations are used to show the variation of peak pressure with depth in the target and throughout the finite volume projectiles. Thermally sensitive biomarker ratios, including ratios of hopanoids and steranes, and the methylphenanthrene ratio, showed an increase in thermal maturity in the ejecta, and especially the projectile, fragments. Measurement of absolute concentrations of selected biomarkers indicates that changes in biomarker ratios reflect synthesis of new material rather than selective destruction. Their presence in ejecta and projectile fragments suggests that fossil biomarkers may survive hypervelocity impacts, and that experiments using biomarker‐rich rock have high potential for testing survival of organic matter in a range of impact scenarios.  相似文献   

The impact of the MJO on clusters of wintertime circulation anomalies over the North American region   总被引：3，自引：2，他引：1  

Emily E. Riddle  Marshall B. Stoner  Nathaniel C. Johnson  Michelle L. L’Heureux  Dan C. Collins  Steven B. Feldstein 《Climate Dynamics》2013,40(7-8):1749-1766

Recent studies have shown that the Madden–Julian Oscillation (MJO) impacts the leading modes of intraseasonal variability in the northern hemisphere extratropics, providing a possible source of predictive skill over North America at intraseasonal timescales. We find that a k-means cluster analysis of mid-level geopotential height anomalies over the North American region identifies several wintertime cluster patterns whose probabilities are strongly modulated during and after MJO events, particularly during certain phases of the El Niño-Southern Oscillation (ENSO). We use a simple new optimization method for determining the number of clusters, k, and show that it results in a set of clusters which are robust to changes in the domain or time period examined. Several of the resulting cluster patterns resemble linear combinations of the Arctic Oscillation (AO) and the Pacific/North American (PNA) teleconnection pattern, but show even stronger responses to the MJO and ENSO than clusters based on the AO and PNA alone. A cluster resembling the positive (negative) PNA has elevated probabilities approximately 8–14 days following phase 6 (phase 3) of the MJO, while a negative AO-like cluster has elevated probabilities 10–20 days following phase 7 of the MJO. The observed relationships are relatively well reproduced in the 11-year daily reforecast dataset from the National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2). This study statistically links MJO activity in the tropics to common intraseasonal circulation anomalies over the North American sector, establishing a framework that may be useful for improving extended range forecasts over this region.  相似文献   

Lessons from co-impacts assessment under the Mitigation Action Plans and Scenarios (MAPS) Programme     

Brett Cohen  Emily Tyler  Marta Torres Gunfaus 《Climate Policy》2013,13(8):1065-1075

The MAPS Programme has been active in Brazil, Chile, Colombia and Peru in supporting the development of an evidence base to inform the processes involved in climate mitigation policy-making. The programme combines detailed quantitative analysis with an extensive stakeholder engagement process to provide policy and decision makers with the information required for long-term climate mitigation planning.

In recognition of the critical need to consider the developmental context and agenda in climate policy-making, the projects undertaken in these countries have experimented with various types of assessments of developmental impacts at both the macro and micro levels. These impacts have been collectively termed co-impacts to reflect the fact that these may be either positive or negative. In this article the value and challenges associated with co-impacts work for climate mitigation policy are considered. The value of including co-impacts analysis in the MAPS processes included increased stakeholder buy-in, making the case for mitigation action, informing INDCs and the prioritization of particular mitigation actions. Challenges include those associated with obtaining locally relevant data, the selection and operation of appropriate macro-economic models and analytical approaches and working with multidisciplinary teams.

The article concludes by making some suggestions to optimize co-impacts work, through reference to other bodies of literature. The authors highlight that this article is situated within a dominant approach to climate mitigation policy work in developing countries, which implicitly places the non-climate benefits of any action as secondary to the primary benefit of climate change mitigation and constructs an artificial separation of policy formulation and implementation. Practitioners are encouraged to reflect on the implications of these considerations in future efforts.

Policy relevance

One of the primary challenges to advancing climate mitigation policy in developing countries is that of perceived relevance: near-term development priorities are overwhelming. Identifying, understanding and engaging with the co-impacts of mitigation actions has emerged as one way of addressing this challenge. Although still at an experimental phase, experience with co-impacts analysis in the MAPS countries provides some useful lessons in how to develop this area of work.  相似文献   

Combining price and quantity instruments: insights from South Africa     

Emily Tyler  Brent Cloete 《Climate Policy》2013,13(3):374-387

A carbon tax will form the central carbon pricing instrument in South Africa. The country, however, is also in the process of setting specific short-term emissions limits at a subnational level. Additional mitigation policy instruments will thus be required to meet these targets. Although it is possible to combine sector-level quantity targets with a broad-based carbon tax, this article finds that this greatly complicates mitigation policy design, increasing both the information requirements and the likelihood of unintended consequences. The trade-offs between economic efficiency (optimized by the use of a broad-based price set by a carbon tax) and environmental effectiveness (optimized by using instruments that ensure emissions reduction targets are met) are ever present. A clear understanding of subnational quantity targets and an appreciation of the characteristics of the instruments to achieve such targets (quantity-based instruments, QBIs), the framework through which the instruments are combined, and their possible interactions, are required for effective policy making. Three possible frameworks for combining instruments are identified in the article, and some specific implications of interaction between particular QBIs and a carbon tax are suggested.

Policy relevance

This article explores the interaction of a carbon tax with mitigation policy instruments to meet subnational emissions targets in the South African context (where both a carbon tax and subnational emissions targets are currently being developed). As international negotiations progress towards countries accepting binding GHG emissions restrictions, quantity-based mitigation policy approaches become more important. In countries where a broad-based emissions trading scheme (ETS) is not feasible in the short to medium term, combining a broad-based carbon tax with subnational emission targets provides an alternative mechanism for achieving the economic efficiency and emissions certainty benefits derived from an ETS. This paper considers the mechanisms through which such a combination of instruments can be achieved. Three possible frameworks for combining instruments are identified, some specific implications of interaction between particular QBIs and a carbon tax are suggested, and guidelines and concept tools are presented to assist policy-makers in designing efficient and coherent mitigation policy.  相似文献   

The Kwakshua Watersheds Observatory,central coast of British Columbia,Canada     

Ian J. W. Giesbrecht  William C. Floyd  Suzanne E. Tank  Ken P. Lertzman  Brian P. V. Hunt  Maartje C. Korver  Allison A. Oliver  Ray Brunsting  Paul Sanborn  Santiago G. Gonzalez Arriola  Gordon W. Frazer  Kyra A. St. Pierre  Shawn Hateley  James McPhail  Colby Owen  Stewart Butler  Bryn Fedje  Emma Myers  Lucy Quayle  Emily Haughton  Isabelle Desmarais  Rob White  David J. Levy-Booth  Colleen T. E. Kellogg  Jennifer M. Jackson  William W. Mohn  Steven J. Hallam  Justin Del Bel Belluz 《水文研究》2021,35(6):e14198

The Kwakshua Watersheds Observatory (KWO) is an integrative watersheds observatory on the coastal margin of a rain-dominated bog-forest landscape in British Columbia (BC), Canada. Established in 2013, the goal of the KWO is to understand and model the flux of terrestrial materials from land to sea – the origins, pathways, processes and ecosystem consequences – in the context of long-term environmental change. The KWO consists of seven gauged watersheds and a network of observation sites spanning from land to sea and along drainage gradients within catchments. Time-series datasets include year-round measurements of weather, soil hydrology, streamflow, aquatic biogeochemistry, microbial ecology and nearshore oceanographic conditions. Sensor measurements are recorded every 5 min and water samples are collected approximately monthly. Additional observations are made during high-flow conditions. We used remote sensing to map watershed terrain, drainage networks, soils and terrestrial ecosystems. The watersheds range in size from 3.2 to 12.8 km², with varying catchment characteristics that influence hydrological and biogeochemical responses. Despite local variation, the overall study area is a global hotspot for yields of dissolved organic carbon, dissolved organic nitrogen and dissolved iron at the coastal margin. This observatory helps fill an important gap in the global network of observatories, in terms of spatial location (central coast of BC), climate (temperate oceanic), hydrology (very high runoff, pluvial regime), geology (igneous intrusive, glacially scoured), vegetation (bog rainforest) and soils (large stores of organic carbon).  相似文献