A NEW CHALLENGE FOR CLIMATE STUDIES IN GEOGRAPHY     

Brent Yarnal  Robert G. Crane  Andrew M. Carleton  Laurence S. Kalkstein 《The Professional geographer》1987,39(4):465-473

Greater emphasis is being placed on large-scale (synoptic and dynamic) climatology in geography. Concurrently, climatological research as a whole has evolved to view climate as a complex, integrated and interactive global system. In this context, we review new directions in large-scale climate studies in geography. We conclude that no matter at which climatic scale geographers are working, the new challenge is to integrate their research and teaching activities into a more holistic, global-systems approach while maintaining and improving their traditional strengths.  相似文献   

Vertical distribution of first stage larvae of the blue crab,Callinectes sapidus,at the mouth of Chesapeake Bay     

Anthony J. Provenzano  John R. McConaugha  Kathleen B. Philips  David F. Johnson  John Clark 《Estuarine, Coastal and Shelf Science》1983,16(5):489-499

The vertical distribution of stage I blue crab larvae, near the mouth of Chesapeake Bay, was examined over four diurnal cycles. Each of two stations was occupied for 30 hours twice during the summer of 1979.On each of the four cruises, peak larval abundance occurred after a night time high slack tide, suggesting a synchronized hatch of blue crab larvae. 90–99% of all larvae collected were taken in the neuston layer. The apparent timing of the hatches to coincide with the beginning of an ebb tide and the concentration of larvae in the neuston layer strongly suggests seaward transport of these early stage larvae and the probability of offshore development.  相似文献   

PILOT: a balloon-borne experiment to measure the polarized FIR emission of dust grains in the interstellar medium     

J-Ph. Bernard  P. Ade  Y. André  J. Aumont  L. Bautista  N. Bray  P. de Bernardis  O. Boulade  F. Bousquet  M. Bouzit  V. Buttice  A. Caillat  M. Charra  M. Chaigneau  B. Crane  J.-P. Crussaire  F. Douchin  E. Doumayrou  J.-P. Dubois  C. Engel  P. Etcheto  P. Gélot  M. Griffin  G. Foenard  S. Grabarnik  P. Hargrave  A. Hughes  R. Laureijs  Y. Lepennec  B. Leriche  Y. Longval  S. Maestre  B. Maffei  J. Martignac  C. Marty  W. Marty  S. Masi  F. Mirc  R. Misawa  J. Montel  L. Montier  B. Mot  J. Narbonne  J-M. Nicot  F. Pajot  G. Parot  E. Pérot  J. Pimentao  G. Pisano  N. Ponthieu  I. Ristorcelli  L. Rodriguez  G. Roudil  M. Salatino  G. Savini  O. Simonella  M. Saccoccio  P. Tapie  J. Tauber  J.-P. Torre  C. Tucker 《Experimental Astronomy》2016,42(2):199-227

Future cosmology space missions will concentrate on measuring the polarization of the Cosmic Microwave Background, which potentially carries invaluable information about the earliest phases of the evolution of our universe. Such ambitious projects will ultimately be limited by the sensitivity of the instrument and by the accuracy at which polarized foreground emission from our own Galaxy can be subtracted out. We present the PILOT balloon project, which aims at characterizing one of these foreground sources, the polarized continuum emission by dust in the diffuse interstellar medium. The PILOT experiment also constitutes a test-bed for using multiplexed bolometer arrays for polarization measurements. This paper presents the instrument and its expected performances. Performance measured during ground calibrations of the instrument and in flight will be described in a forthcoming paper.  相似文献   

Human Influence at the Coast: Upland and Shoreline Stressors Affect Coastal Macrofauna and Are Mediated by Salinity     

Rochelle D. Seitz  Kathleen E. Knick  Theresa M. Davenport  Gabrielle G. Saluta 《Estuaries and Coasts》2018,41(1):114-127

Observations and predictions regarding oceanic intrusions at the entrance to Puget Sound, WA (USA), are presented. Four years of seabed observations at Admiralty Inlet show episodic periods high salinity, coincident with landward residual currents near the seabed. The observed residual currents are consistent with an estuarine exchange flow during minimal tidal mixing, coincident with neap currents and maximum diurnal inequalities. These subtidal intrusions can carry dense water into Puget Sound and, thereby, renew the bottom water that is trapped landward of the sill. The oxygen concentration levels of these intrusions are often low, though not hypoxic, and may influence the oxygen levels in Puget Sound. The water mass properties of these intrusions are influenced strongly by regional dynamics, because the entrance to Puget Sound is connected to the open ocean via the Strait of Juan de Fuca. Coastal upwelling and discharge from the Fraser River discharge control the exchange flow in the Strait of Juan de Fuca and thus control the availability of dense water at the entrance to Puget Sound. The net effect of the tidal and regional dynamics is for intrusions with low oxygen levels to prevail in the late summer months. To predict intrusions in future years, an empirical method is developed and validated for daily application. The prediction method is based on publicly available operational data products and does not require in situ observations. In verification, 98% of intrusion events with dissolved oxygen less than 4.0 mg/L are successfully identified in a hindcast prediction for the 4-year observational record.  相似文献   

Strontium Isotopic Signatures of Streams from Taylor Valley, Antarctica, Revisited: The Role of Carbonate Mineral Dissolution     

Carolyn B. Dowling  W. B. Lyons  Kathleen A. Welch 《Aquatic Geochemistry》2013,19(3):231-240

We have collected and analyzed a larger set of stream waters for major ions and strontium isotopes in Taylor Valley, McMurdo Dry Valleys, Antarctica. These new data substantiate the concept that the dissolution of carbonate minerals is a significant source of strontium, even in polar desert environments where liquid water is primarily limited to stream channels. In Taylor Valley, most of the carbonate minerals present are the result of secondary processes, such as mineral precipitation and/or eolian deposition, and not through primary geologic sources, such as bedrock or till sources. In Von Guerard Stream (Lake Fryxell basin) and Andersen Creek (Lake Hoare basin), water samples were collected during the austral summer to determine short-term ⁸⁷Sr/⁸⁶Sr patterns. The observed variability in both time and space may be dependent on the relative amounts of primary and secondary carbonates present in the streambeds and hyporheic zone as well as contingent on the relative proportions of carbonate and aluminosilicate weathering.  相似文献   

Can saltwater toxicity be predicted from freshwater data?   总被引：3，自引：0，他引：3  

K M Leung  D Morritt  J R Wheeler  P Whitehouse  N Sorokin  R Toy  M Holt  M Crane 《Marine pollution bulletin》2001,42(11):1007-1013

The regulation of substances discharged to estuarine and coastal environments relies upon data derived from ecotoxicity tests. Most such data are generated for freshwater rather than saltwater species. If freshwater toxicity data are related to saltwater toxic effects in a systematic and predictable way, the former can be used to predict the latter. This would have economic advantages due to a reduction in toxicity testing of saltwater species. If toxicity data are plotted as species sensitivity distributions, four theoretical relationships between freshwater and saltwater can be envisaged. Examples show that each one of these relationships is supported by empirical data. These examples show that although there is considerable potential for freshwater to saltwater prediction, species parity and representativeness need to be examined for each chemical substance to avoid bias.  相似文献   

Using DNA‐Stable Isotope Probing to Identify MTBE‐ and TBA‐Degrading Microorganisms in Contaminated Groundwater     

Katherine C. Key  Kerry L. Sublette  Kathleen Duncan  Douglas M. Mackay  Kate M. Scow  Dora Ogles 《Ground Water Monitoring & Remediation》2013,33(4):57-68

Although the anaerobic biodegradation of methyl tert‐butyl ether (MTBE) and tert‐butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA‐stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate‐reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio‐Sep® beads amended with ¹³C₅‐MTBE, ¹³C₁‐MTBE (only methoxy carbon labeled), or ¹³C₄‐TBA. ¹³C‐DNA and ¹²C‐DNA extracted from the Bio‐Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the tert‐butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading ¹³C‐labeled MTBE and TBA in situ and the ¹³C was incorporated into their DNA. Several sequences related to known MTBE‐ and TBA‐degraders in the Burkholderiales and the Sphingomonadales orders were detected in all three ¹³C clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate‐reducing bacteria and iron‐reducers, such as Geobacter and Geothrix, were only detected in the clone libraries where MTBE and TBA were fully labeled with ¹³C, suggesting that they were involved in processing carbon from the tert‐butyl group. Sequences similar to the Pseudomonas genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with ¹³C. It is likely that members of this genus were secondary degraders cross‐feeding on ¹³C‐labeled metabolites such as acetate.  相似文献   

Global change revealed by palaeolimnological records from remote lakes: a review   总被引：1，自引：0，他引：1  

Jordi Catalan  Sergi Pla-Rabés  Alexander P. Wolfe  John P. Smol  Kathleen M. Rühland  N. John Anderson  Jiři Kopáček  Evžen Stuchlík  Roland Schmidt  Karin A. Koinig  Lluís Camarero  Roger J. Flower  Oliver Heiri  Christian Kamenik  Atte Korhola  Peter R. Leavitt  Roland Psenner  Ingemar Renberg 《Journal of Paleolimnology》2013,49(3):513-535

Over recent decades, palaeolimnological records from remote sites have provided convincing evidence for the onset and development of several facets of global environmental change. Remote lakes, defined here as those occurring in high latitude or high altitude regions, have the advantage of not being overprinted by local anthropogenic processes. As such, many of these sites record broad-scale environmental changes, frequently driven by regime shifts in the Earth system. Here, we review a selection of studies from North America and Europe and discuss their broader implications. The history of investigation has evolved synchronously with the scope and awareness of environmental problems. An initial focus on acid deposition switched to metal and other types of pollutants, then climate change and eventually to atmospheric deposition-fertilising effects. However, none of these topics is independent of the other, and all of them affect ecosystem function and biodiversity in profound ways. Currently, remote lake palaeolimnology is developing unique datasets for each region investigated that benchmark current trends with respect to past, purely natural variability in lake systems. Fostering conceptual and methodological bridges with other environmental disciplines will upturn contribution of remote lake palaeolimnology in solving existing and emerging questions in global change science and planetary stewardship.  相似文献   

Barrier dynamics for GIS: a design pattern for geospatial barriers     

Emily White  Kathleen Stewart 《International journal of geographical information science》2013,27(6):1007-1022

When separation between geospatial features is desired, an obstacle or barrier is used to maintain distance between the features. Barriers are used in a wide variety of domains, such as hazards, transportation, and public safety. Floodwalls, for example, prevent flooding rivers or lakes from inundating buildings. This work presents an ontology design pattern for barriers and barring events useful for GIS. In this ontology design pattern, active features (e.g., the water-body that is causing flooding) and target features (e.g., buildings requiring flood protection) are defined. Along with these key features, the ontology design pattern also captures certain barring events. These are the dynamics that arise from the placement of barriers and include Blocking, Enclosing, KeepingIn and KeepingOut, involving interactions among barriers, and active and target features. The set of classes that model these features and events as well as the relations between them are presented and formalized. This design pattern is ready for integration in a GIS to allow queries on barriers and barring events that do not currently have explicit support in most GIS.  相似文献   

Hybrid drinking water governance: Community participation and ongoing neoliberal reforms in rural Rajasthan,India     

Kathleen O’Reilly  Richa Dhanju 《Geoforum》2012,43(3):623-633

This paper examines a Rajasthan (India) drinking water supply project that relied on hybrid governance reforms in its original design. Decentralization and marketization, combined with a participatory approach, were intended to facilitate an empowering shift in state-citizen relationships. Paying citizens were expected to make quantity and quality demands of the state as consumers, not welfare beneficiaries. Research on the project 3 years after its completion revealed that although payment for water and community participation were intended to compel the state to provide clean water, they failed in this regard. The problem of an unreliable state supply was solved through small scale privatization, a decision ‘independently’ reached at the local scale, but one that served to further undermine the state’s ability to provide clean water.In this paper, we trace the shifts in regulation that evolved in the post-project phase at both the state and village scale that resulted in the delivery of contaminated water. Ethnographic research indicates that community participation was introduced as a set of institutions that would govern how villagers interacted with the state and its water supply, but villagers altered community participation by introducing reforms in water governance as a way of coping with an unresponsive state and increased work burden. Community participation evolved in contradictory ways as the impacts of neoliberal environmental governance were felt. The paper contributes to understandings of neoliberalization processes’ local impacts by analyzing their ongoing hybridization at multiple scales. It further calls into question foundational notions that community participation in resource governance is the appropriate solution to drinking water supply.  相似文献