Climate change impacts on U.S. Coastal and Marine Ecosystems   总被引：1，自引：0，他引：1  

Donald Scavia  John C. Field  Donald F. Boesch  Robert W. Buddemeier  Virginia Burkett  Daniel R. Cayan  Michael Fogarty  Mark A. Harwell  Robert W. Howarth  Curt Mason  Denise J. Reed  Thomas C. Royer  Asbury H. Sallenger  James G. Titus 《Estuaries and Coasts》2002,25(2):149-164

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO₂. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO₂ levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.  相似文献   

North African Lakes, Edited by R. J. Flower (Book Review)     

J. Curt Stager 《Journal of Paleolimnology》2002,28(4):491-492

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Holocene climate variability   总被引：17，自引：0，他引：17  

Paul A. Mayewski  Eelco E. Rohling  J. Curt Stager  Wibjrn Karln  Kirk A. Maasch  L. David Meeker  Eric A. Meyerson  Francoise Gasse  Shirley van Kreveld  Karin Holmgren  Julia Lee-Thorp  Gunhild Rosqvist  Frank Rack  Michael Staubwasser  Ralph R. Schneider  Eric J. Steig 《Quaternary Research》2004,62(3):243-255

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Atmospheric and oceanic heat transport: Simulations versus observations     

Curt Covey 《Climatic change》1988,13(2):149-159

Poleward transport of heat by the atmosphere as simulated by a recently developed general circulation model (GCM) is consistent with earlier GCM studies in being significantly greater than indicated from radiosonde (weather balloon) observations. However, total heat transport by the combined ocean-atmosphere system appears to be approximately the same in the models and in satellite observations of irradiances at the top of the atmosphere: in the models most of this transport takes place in the atmosphere whereas the combined satellite and radiosonde observations indicate that half or more of the transport takes place in the oceans. It is argued here that the atmospheric model results are generally closer to the truth than the radiosonde observations. If this is true, then the oceans transport less heat than often supposed, and conventional ideas about the genesis of climatic change through alterations in oceanic heat transport must be reexamined.  相似文献   

Book reviews     

Melinda Meade  Curt Covey  J. Salinger  T. Rabb  Peter Timmerman 《Climatic change》1983,5(2):193-200

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Simple gravity corer suitable for educators     

J. Curt Stager 《Journal of Paleolimnology》1992,7(3):253-255

Instructions for construction and use of a simple and inexpensive sediment coring device are presented. The sampler is suitable for use in high school and undergraduate science courses.  相似文献   

Australia and Gondwanaland   总被引：2，自引：0，他引：2  

Curt Teichert 《International Journal of Earth Sciences》1959,47(2):562-590

Along the western margin of the Australian continent there exist four major sedimentary basins, filled with predominantly marine rocks from Cambrian to Tertiary in age, and up to 40,000 feet thick. Seaward these basins continue into depressions recognizable in the continental shelf and even the continental slope. Their very presence, the nature of their sediments and the composition and relationships of their fossil faunas indicate the existence of an open ocean to the west of Australia since early Paleozoic time. Composition of the Australian fossil land vertebrate faunas suggests isolation of the Australian continent since at least Permian time.A condensed version of this paper was presented at the XX International Geological Congress in Mexico, September 1956. Publication authorized by the Director, U. S. Geological Survey.The writer is greatly indebted to B. E.Balme, B. F.Glenister, A. W.Lindner, J. R. H.McWhae, and P. E.Playford for brief summaries of important new stratigraphic and paleontological studies. These were communicated to the writer by B. F.Glenister and are, in their proper places, acknowledged asMcWhae et al., ms. In the meantime this work appeared under the title Stratigraphy of Western Australia in Jour. Geol. Soc. Australia, vol. 4, pt. 2, 1958, p. 1–161, after the present paper had gone to press. For stratigraphical details the reader is referred to this authoritative publication.  相似文献   

Quantifying anthropogenic influence on recent near-surface temperature change   总被引：2，自引：0，他引：2  

M. R. Allen  N. P. Gillett  J. A. Kettleborough  G. Hegerl  R. Schnur  P. A. Stott  G. Boer  C. Covey  T. L. Delworth  G. S. Jones  J. F. B. Mitchell  T. P. Barnett 《Surveys in Geophysics》2006,27(5):491-544

We assess the extent to which observed large-scale changes in near-surface temperatures over the latter half of the twentieth century can be attributed to anthropogenic climate change as simulated by a range of climate models. The hypothesis that observed changes are entirely due to internal climate variability is rejected at a high confidence level independent of the climate model used to simulate either the anthropogenic signal or the internal variability. Where the relevant simulations are available, we also consider the alternative hypothesis that observed changes are due entirely to natural external influences, including solar variability and explosive volcanic activity. We allow for the possibility that feedback processes, other than those simulated by the models considered, may be amplifying the observed response to these natural influences by an unknown amount. Even allowing for this possibility, the hypothesis of no anthropogenic influence can be rejected at the 5% level in almost all cases. The influence of anthropogenic greenhouse gases emerges as a substantial contributor to recent observed climate change, with the estimated trend attributable to greenhouse forcing similar in magnitude to the total observed warming over the 20th century. Much greater uncertainty remains in the response to other external influences on climate, particularly the response to anthropogenic sulphate aerosols and to solar and volcanic forcing. Our results remain dependent on model-simulated signal patterns and internal variability, and would benefit considerably from a wider range of simulations, particularly of the responses to natural external forcing.  相似文献   

Beware the Elegance of the Number Zero     

Curt Covey 《Climatic change》2000,44(4):409-411

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Diurnal variability in turbidity and coral fluorescence on a fringing reef flat: Southern Molokai,Hawaii     

Gregory A. Piniak  Curt D. Storlazzi 《Estuarine, Coastal and Shelf Science》2008

Terrigenous sediment in the nearshore environment can pose both acute and chronic stresses to coral reefs. The reef flat off southern Molokai, Hawaii, typically experiences daily turbidity events, in which trade winds and tides combine to resuspend terrigenous sediment and transport it alongshore. These chronic turbidity events could play a role in restricting coral distribution on the reef flat by reducing the light available for photosynthesis. This study describes the effects of these turbidity events on the Hawaiian reef coral Montipora capitata using in situ diurnal measurements of turbidity, light levels, and chlorophyll fluorescence yield via pulse-amplitude-modulated (PAM) fluorometry. Average surface irradiance was similar in the morning and the afternoon, while increased afternoon turbidity resulted in lower subsurface irradiance, higher fluorescence yield (ΔF/F_m^′), and lower relative electron transport rates (rETR). Model calculations based on observed light extinction coeffecients suggest that in the absence of turbidity events, afternoon subsurface irradiances would be 1.43 times higher than observed, resulting in rETR for M. capitata that are 1.40 times higher.  相似文献