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1.
Little Salt Spring in southwest Florida, consisting of a shallow, water-filled basin above a deep, vertical underwater cavern, was a freshwater cenote in the peninsula's drier past. It collected and preserved perishable organic artifacts and other evidence of Paleo-Indian and Archaic Indian origin ranging in age from 12,000 to 9000 and from 6800 to 5200 years ago. An Archaic Period cemetery containing an estimated 1000 burials occupies an adjoining muck-filled slough and presently drowned portions of the basin of the spring. Artifacts and the nature of interment suggest a cultural link between the Archaic people and the much later Glades Tradition of southern Florida.  相似文献   

2.
Whole rock potassium-argon ages for samples of subsurface basalt recovered near Charleston, South Carolina, are interpreted to indicate a Triassic or Jurassic age for the basalt and underlying sedimentary red beds. This age is consistent with existing evidence indicating that an early Mesozoic basin is present in the subsurface of a large part of the coastal plain of South Carolina, Georgia, Florida, and Alabama.  相似文献   

3.
Annual and interannual variations in the Florida Current, Caribbean, and subtropical Atlantic are investigated with the use of historical sea level differences and wind field data. Observational and model evidence suggests that the seasonal transport cycle of the Florida Current is locally forced, either upstream in the Caribbean or downstream over topography. Although at seasonal and shorter periods sea level or bottom pressure fluctuations on the left side of the Florida Current contribute almost all of the variance of sea level difference across the Florida Straits and hence transport, this relation does not seem to apply at interannual time scales. Using results from the Subtropical Atlantic Climate Studies, it is estimated from historical sea level data that interannual transport fluctuations of the Florida Current are only of order 1 x 10(6) cubic meters per second. Interannual fluctuations in the 2- to 3-year period range in the Florida Straits seem to be correlated with sea level differences across the Caribbean and the subtropical Atlantic but not with Sverdrup transport fluctuations in the subtropical Atlantic.  相似文献   

4.
不同果草模式下土壤理化性状分析   总被引:3,自引:0,他引:3  
程斯  何丙辉  王侨  苏锋 《安徽农业科学》2009,37(10):4575-4577
[目的]寻求适合三峡库区的“果—草”模式。[方法]在重庆三峡库区万州区内,设3种果—草模式处理:佛罗橙—紫花苜蓿,套种1年(T1)、佛罗橙—北海道牧草,套种2年(T2)、佛罗橙—白三叶,套种1年(T3),系统地研究了不同果草模式对土壤理化性状的影响。[结果]3种果草套种模式均能有效改善土壤养分状况,增加土壤肥力,其中以T1和T2模式的养分含量最优;能增加土壤中大孔隙的含量,提高土壤渗透速度,其中以T2模式最大,达到8.03 mm/min;能够提高土壤中较大颗粒的含量,有利于土壤养分的富集,其中以T1和T2模式的效果最显著。[结论]佛罗橙—北海道牧草模式和佛罗橙—紫花苜蓿模式是适合三峡库区的较为理想的果—草模式。  相似文献   

5.
The high cumulative incidence of AIDS and the large percentage of AIDS patients with no identified risks in Belle Glade, Florida, were evaluated through case interviews and neighborhood-based seroepidemiologic studies. It was found that of 93 AIDS patients reported between July 1982 and 1 August 1987, 34 could be directly linked to at least one other AIDS patient or to a person with AIDS-related complex by sexual contact, sharing of needles during intravenous drug abuse (or both), or perinatal exposure; of 877 randomly selected adults, 28 had antibodies to HIV; no person over age 60 and none of 138 children aged 2 to 10 years had antibodies to HIV; no clustering of infected persons within households occurred, except in sex partners; and HIV-seropositive adults were more likely than HIV-seronegative adults to be from Haiti, have a lower income, report sex with intravenous drug abusers, and have a history of previous treatment for sexually transmitted diseases. The presence of antibodies to five arboviruses prevalent in South Florida or the Caribbean did not correlate significantly with HIV infection. The high cumulative rate of AIDS in Belle Glade appears to be the result of HIV transmission through sexual contact and intravenous drug abuse; the evidence does not suggest transmission of HIV through insects.  相似文献   

6.
Six sympatric species of 5-million-year-old (late Hemphillian) horses from Florida existed during a time of major global change and extinction in terrestrial ecosystems. Traditionally, these horses were interpreted to have fed on abrasive grasses because of their high-crowned teeth. However, carbon isotopic and tooth microwear data indicate that these horses were not all C4 grazers but also included mixed feeders and C3 browsers. The late Hemphillian Florida sister species of the modern genus Equus was principally a browser, unlike the grazing diet of modern equids. Late Hemphillian horse extinctions in Florida involved two grazing and one browsing species.  相似文献   

7.
Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination ofr(2) = 0.93, and Miami sea level, when adjusted for weather effects, had r(2) = 0.74; the standard errors of estimating transports were +/- 1.2 x 10(6) and +/- 1.9 x 10(6) cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r(2) = 0.94 with a standard error of estimating transport of +/- 1.1 x 10(6) cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequatelv monitor the daily volume transport fluctuations of the Florida Current.  相似文献   

8.
张红星 《现代农业科技》2010,(10):326-328,331
在我国黄河中游流域自然水域中已发现了鳄龟、佛罗里达鳖,这是一个危险且值得高度警惕的信号。针对鳄龟、佛罗里达鳖、乌龟和中华鳖的有关生物学习性进行对比,指出当鳄鱼、佛罗里达鳖达到一定数量时,流域内原生的乌龟和中华鳖的生态位将会受到严重威胁,建议相关领域学者重视对两栖爬行动物等外来物种在中国的入侵状况与控制策略的研究。  相似文献   

9.
A deposit of fossil seabirds from the late Pliocene of Florida includes more than 130 skeletons of an extinct cormorant that is related phylogenetically to Recent species currently restricted to the eastern north Pacific. Evidence suggests the birds died in a single catastrophic event, perhaps a red tide. The fossil cormorant, along with other extinct seabirds and marine mammals, supports molluscan evidence for cold-water upwelling along the Florida Gulf Coast during the Pliocene. A decline in species richness of marine vertebrates throughout the Pliocene of Florida coincides with cessation of upwelling after emergences of the Panamanian Land Bridge.  相似文献   

10.
Samples of natural fine-grained carbonate sediment from Florida Bay, Florida, undergo mole-for-mole cation exchange with aqueous solutions of MgCl(2) and CaCl(2) in the laboratory. The exchange reaction, which involves the surface of the grains of sediment, can be essentially described by a simple mass action-law equation. Enrichment of Mg++ beyond the amounts found within particle interiors should take place on the surface of CaCo(3) sediments immersed in sea water; it may be on both exchangeable and unexchangeable sites.  相似文献   

11.
Two whales were observed closely for an hour off Sarasota, Florida, by residents who provided observations of structural details which identify only the right whale, Eubalaena glacialis, a temperate and subpolar species previously known to range to the Florida east coast, but not to enter the Gulf of Mexico.  相似文献   

12.
Average species durations were estimated for 131 commonly occurring modern species. The duration of species occurring at depths of less than 200 meters is 16 million years, while for those at greater than 200 meters and at all depths it is 25 to 26 million years. Species (less than 200 meters) distributed from Florida to Newfoundland and from Florida to Cape Hatteras have about the same durations (18 to 20 million years). The duration for species restricted to north of Cape Hatteras is only 7 million years. The data suggest that evolutionary rates are greater in shallower than in deeper depths and greatest in the shallower northern area.  相似文献   

13.
Rehm A  Humm HJ 《Science (New York, N.Y.)》1973,182(4108):173-174
Sphaeroma terebrans, a wood-boring isopod, is destroying the prop roots of red mangroves along the southwestern coast of Florida to such an extent that the Ten Thousand Islands and mangrove fringes of the mainland are steadily shrinking. Mangroves of the Florida Keys apparently are free of this wood borer.  相似文献   

14.
43种园林树木引种研究   总被引:5,自引:0,他引:5  
43种园林树木分属 18科 30属,共 2 78株。原产地分布于中国、朝鲜、日本。大部分树种已能初步适应本地环境条件,以原产地在我国东北、华北地区的树种引种表现较好。其中红王子绵带、花叶锦带等观赏树种具有更为广阔的应用前景  相似文献   

15.
Carbon and oxygen isotope analysis through a 30-year (1944 to 1974) growth of Montastrea annularis from Hen and Chickens Reef (Florida Keys) shows a strong yearly variation in the abundances of both carbon-13 and oxygen-18 and a broad inverse relationship between the two isotopes. Normal annual dense bands are formed during the summer and are characterized by heavy carbon and light oxygen. "Stress bands" are formed during particularly severe winters and are characterized by heavy carbon and heavy oxygen. The isotopic effect of Zooxanthellae metabolism dominates the temperature effect on the oxygen-18/oxygen-16 ratio. The isotopic results on the deep-sea solitary coral Bathypsammia tintinnabulum, where Zooxanthellae are nonexistent, indicates that the abundance of the heavy isotopes carbon-13 and oxygen-18 is inversely related to the growth rate, with both carbon and oxygen approaching equilibrium values with increasing skeletal age.  相似文献   

16.
Absolute velocity and temperature profiles are used to estimate the volume transport through the Straits of Florida and, in combination with historical midbasin data, to estimate the total meridional heat flux through a section at 27 degrees N. The mean annual volume transport of the Florida Current from April 1982 through August 1983 is 30.5 (+/- 1)x 10(6) cubic meters per second. The net northward heat flux through the 27 degrees N section is 1.2 (+/- 0.1)x 10(15) watts. The volume transport is characterized by high values in the late spring and early summer and low values in the late fall and early winter. There is a similar cycle in total heat flux.  相似文献   

17.
本文论述了美国东南部(佛罗里达州)园林的类型,并对其中重要的类型如专类园林、专类游乐性园林、游乐园林及综合性园林,从规划设计的角度探讨了它们的特点。  相似文献   

18.
The rediscovery of remnant Florida panthers (Puma concolor coryi) in southern Florida swamplands prompted a program to protect and stabilize the population. In 1995, conservation managers translocated eight female pumas (P. c. stanleyana) from Texas to increase depleted genetic diversity, improve population numbers, and reverse indications of inbreeding depression. We have assessed the demographic, population-genetic, and biomedical consequences of this restoration experiment and show that panther numbers increased threefold, genetic heterozygosity doubled, survival and fitness measures improved, and inbreeding correlates declined significantly. Although these results are encouraging, continued habitat loss, persistent inbreeding, infectious agents, and possible habitat saturation pose new dilemmas. This intensive management program illustrates the challenges of maintaining populations of large predators worldwide.  相似文献   

19.
Dense biological communities of large epifaunal taxa similar to those found along ridge crest vents at the East Pacific Rise were discovered in the abyssal Gulf of Mexico. These assemblages occur on a passive continental margin at the base of the Florida Escarpment, the interface between the relatively impermeable hemipelagic clays of the distal Mississippi Fan and the jointed Cretaceous limestone of the Florida Platform. The fauna apparently is nourished by sulfide rich hypersaline waters seeping out at near ambient temperatures onto the sea floor.  相似文献   

20.
The acidity of rainfall in Florida has increased markedly in the past 25 years, and the average sulfate and nitrate concentrations have increased by factors of 1.6 and 4.5, respectively, over the period. Annual average pH values below 4.7 now occur over the northern three quarters of the state. Summer rainfall has average pH values 0.2 to 0.3 unit lower than winter rainfall, and sulfate concentrations at most sites are higher in summer. The annual deposition of H(+) (about 300 to 500 equivalents per hectare) in northern Florida is a third to a half of the deposition in the heavily impacted northeastern United States; comparable figures for excess sulfate (derived from sulfur dioxide) are 7 to 11 kilograms of sulfur per hectare or 50 to 90 percent of the sulfate deposition rates at Hubbard Brook, New Hampshire.  相似文献   

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