Defining and detecting undesirable disturbance in the context of marine eutrophication   总被引：1，自引：0，他引：1  

Tett P  Gowen R  Mills D  Fernandes T  Gilpin L  Huxham M  Kennington K  Read P  Service M  Wilkinson M  Malcolm S 《Marine pollution bulletin》2007,55(1-6):282-297

An understanding of undesirable disturbance to the balance of organisms is needed to diagnose marine eutrophication as defined by EU Directives and OSPAR. This review summarizes the findings of the UK Defra-funded Undesirable Disturbance Study Team, which concluded that 'an undesirable disturbance is a perturbation of a marine ecosystem that appreciably degrades the health or threatens the sustainable human use of that ecosystem'. A methodology is proposed for detecting disturbance of temperate salt-water communities dominated by phytoplanktonic or phytobenthic primary producers. It relies on monitoring indicators of ecosystem structure and vigour, which are components of health. Undesirable disturbance can be diagnosed by accumulating evidence of ecohydrodynamic type-specific changes in: (i) bulk indicators; (ii) frequency statistics; (iii) flux measurements; (iv) structural indicators; and (v) indicator species. These are exemplified by (i) chlorophyll, transparency, dissolved oxygen, and opportunistic seaweed cover; (ii) HABs frequency; (iii) primary production; (iv) benthic and planktonic 'trophic indices'; (v) seagrasses and Nephrops norvegicus. Ecological Quality Objectives are proposed for some of these. Linking the diagnosis to eutrophication requires correlation of changes with nutrient enrichment. The methodology, which requires the development of a plankton community index and emphasizes the importance of primary production as an indicator of vigour, can be harmonized with the EU Water Framework Directive and OSPAR's Strategy to Combat Eutrophication.  相似文献   

Desert heat island study in winter by mobile transect and remote sensing techniques   总被引：1，自引：0，他引：1  

Chen-Yi Sun  Anthony J. Brazel  Winston T. L. Chow  Brent C. Hedquist  Lela Prashad 《Theoretical and Applied Climatology》2009,98(3-4):323-335

A familiar problem in urban environments is the urban heat island (UHI), which potentially increases air conditioning demands, raise pollution levels, and could modify precipitation patterns. The magnitude and pattern of UHI effects have been major concerns of a lot of urban environment studies. Typically, research on UHI magnitudes in arid regions (such as Phoenix, AZ, USA) focuses on summer. UHI magnitudes in Phoenix (more than three million population) attain values in excess of 5°C. This study investigated the early winter period—a time when summer potential evapotranspiration >250 mm has diminished to <90 mm. An analysis of the winter magnitude of the heat island in Phoenix has been studied very little, and therefore with the aid of automobile transects, fixed stations, and remote sensing techniques, we investigated a portion of the large Phoenix metropolitan area known as the East Valley. The eastern fringes of the metropolitan area abut against breaks in sloping terrain. The highest UHI intensity observed was >8.0°C, comparable to summertime UHI conditions. Through analysis of the Oke (1998) weather factor Φ_W, it was determined thermally induced nighttime cool drainage winds could account for inflating the UHI magnitude in winter.  相似文献   

Carbon offsets, reversal risk and US climate policy     

Bryan K Mignone  Matthew D Hurteau  Yihsu Chen  Brent Sohngen 《Carbon balance and management》2009,4(1):3-6

Background  

One controversial issue in the larger cap-and-trade debate is the proper use and certification of carbon offsets related to changes in land management. Advocates of an expanded offset supply claim that inclusion of such activities would expand the scope of the program and lower overall compliance costs, while opponents claim that it would weaken the environmental integrity of the program by crediting activities that yield either nonexistent or merely temporary carbon sequestration benefits. Our study starts from the premise that offsets are neither perfect mitigation instruments nor useless "hot air."  相似文献   

Digital imaging and public engagement in palaeontology     

Karl T. Bates  Peter L. Falkingham  David Hodgetts  James O. Farlow  Brent H. Breithaupt  Mike O'Brien  Neffra Matthews  William I. Sellers  & Phillip L. Manning 《Geology Today》2009,25(4):134-139

Public engagement and the promotion of science to a wider non-academic audience form an integral role of the professional scientist in the twenty-first century. The high level of public interest in palaeontology means that the Earth's prehistoric past can provide an important medium through which to communicate information concerning contemporary scientific issues. Here we explain how modern computer techniques can be used to enhance public understanding of complex palaeontological issues.  相似文献   

Comment on Zhang Y., Ye S., and Wu J. 2011. A modified global model for predicting the tritium distribution in precipitation, 1960–2005. Hydrological Processes 25:2379–2392     

Brent D. Newman  Luis J. Araguás‐Araguás  Pradeep K. Aggarwal 《水文研究》2013,27(8):1286-1287

  相似文献   

Advance,deglacial and sea‐level chronology for Foxe Peninsula,Baffin Island,Nunavut          下载免费PDF全文

Daniel J. Utting  John C. Gosse  Samuel E. Kelley  Kayla J. Vickers  Brent C. Ward  Michelle S. Trommelen 《Boreas: An International Journal of Quaternary Research》2016,45(3):439-454

The impact of the Laurentide Ice Sheet (LIS) deglaciation on Northern Hemisphere early Holocene climate can be evaluated only once a detailed chronology of ice history and sea‐level change is established. Foxe Peninsula is ideally situated on the northern boundary of Hudson Strait, and preserves a chronostratigraphy that provides important glaciological insights regarding changes in ice‐sheet position and relative sea level before and after the 8.2 ka cooling event. We utilized a combination of radiocarbon ages, adjusted with a new locally derived ΔR, and terrestrial in‐situ cosmogenic nuclide (TCN) exposure ages to develop a chronology for early‐Holocene events in the northern Hudson Strait. A marine limit at 192 m a.s.l., dated at 8.1–7.9 cal. ka BP, provides the timing of deglaciation following the 8.2 ka event, confirming that ice persisted at least north of Hudson Bay until then. A moraine complex and esker morphosequence, the Foxe Moraine, relates to glaciomarine outwash deltas and beaches at 160 m a.s.l., and is tightly dated at 7.6 cal. ka BP with a combination of shell dates and exposure ages on boulders. The final rapid collapse of Foxe Peninsula ice occurred by 7.1–6.9 cal. ka BP (radiocarbon dates and TCN depth profile age on an outwash delta), which supports the hypothesis that LIS melting contributed to the contemporaneous global sea‐level rise known as the Catastrophic Rise Event 3 (CRE‐3).  相似文献   

Participatory methods of incorporating scientific with traditional knowledge for volcanic hazard management on Ambae Island,Vanuatu   总被引：6，自引：1，他引：5  

Shane?J.?CroninEmail author  David?R.?Gaylord  Douglas?Charley  Brent?V.?Alloway  Sandrine?Wallez  Job?W.?Esau 《Bulletin of Volcanology》2004,66(7):652-668

Ambae Island is the largest of Vanuatus active volcanoes. It is also one of the nations potentially most dangerous, with 60 million m³ of lake-water perched at over 1340 m in the summit caldera and over the active vent. In 1995, small phreatic explosions, earthquake swarms and heightened gas release led to calls for evacuation preparation and community volcanic hazard awareness programs for the ~9500 inhabitants. Differences in perspective or world-view between the island dwellers adhering to traditional beliefs (Kastom) and external scientists and emergency managers led to a climate of distrust following this crisis. In an attempt to address these issues, rebuild dialogue and respect between communities, outside scientists and administrators, and move forward in volcanic hazard education and planning for Ambae, we adapted and applied Participatory Rural Appraisal (PRA) approaches. Initial gender-segregated PRA exercises from two representative communities provided a mechanism for cataloguing local traditional viewpoints and hazard perceptions. Ultimately, by combining elements of these viewpoints and perceptions with science-based management structures, we derived volcanic hazard management guidelines, supported by an alert system and map that were more readily accepted by the test communities than the earlier top-down plans imposed by outside governmental and scientific agencies. The strength of PRA approaches is that they permit scientists to understand important local perspective issues, including visualisations of volcanic hazards, weaknesses in internal and external communication systems, and gender and hierarchy conflicts, all of which can hinder community emergency management. The approach we describe has much to offer both developing and industrialised communities that wish to improve their awareness programs and mitigative planning. This approach should also enhance communication and understanding between volcanologists and the communities they serve.  相似文献   

Economy, Politics and Institutions: From Adaptation to Adaptive Management in Climate Change     

Alexander Thompson  Paul Robbins  Brent Sohngen  Joseph Arvai  Tomas Koontz 《Climatic change》2006,78(1):1-5

  相似文献   

The use of²³⁴Th/²³⁸ disequilibrium to examine the fate of particle-reactive species on the Yangtze continental shelf     

Brent A. McKee  David J. DeMaster  Charles A. Nittrouer 《Earth and Planetary Science Letters》1984,68(3):431-442

  相似文献   

Chemical and isotopic evaluation of water sources to the fens of South Park,Colorado   总被引：1，自引：0，他引：1  

Jenny B. Chapman  Brent Lewis  Greg Litus 《Environmental Geology》2003,43(5):533-545

  相似文献