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201.
The authors present stratigraphic data from Los Buchillones, a now submerged Taino village on the north coast of central Cuba that was occupied from some time prior to A.D. 1220 until 1640 or later. Los Buchillones is one of the best‐preserved sites in the Caribbean, with material culture remains that include palm thatch and wooden structural elements from some of the more than 40 collapsed structures. The purpose of this study was to investigate the environment and site‐formation processes of the Taino settlement. Sediment cores were sampled from the site and its vicinity to permit integration of the geological and archaeological stratigraphies. The cores were analyzed for color, texture, mollusk content, elemental geochemistry, and mineralogy. The results of the stratigraphic work are consistent with regional sealevel data that shows relative sea level has risen gradually during the late Holocene, but has remained relatively stable since the time the Taino first occupied Los Buchillones. Of the two structures partially cleared, at least one appears to have been built over the water, supported on pilings. Site selection is likely to have resulted from a consideration of environmental factors, such as access to marine, terrestrial, and lagoonal resources, and proximity to freshwater springs. © 2006 Wiley Periodicals, Inc. 相似文献
202.
Paul W. Richardson Jayme E. Seehafer Elizabeth T. Keppeler Diane G. Sutherland Joseph W. Wagenbrenner Kevin D. Bladon Salli F. Dymond Ryan P. Cole 《水文研究》2021,35(6):e14207
The Caspar Creek Experimental Watersheds are the site of a long-term paired watershed study in the northern Coast Ranges of California. The watersheds are predominately forested with coast redwood and Douglas-fir. Old-growth forest was logged between 1860 and 1904. Two harvesting experiments have been completed since then and a third experiment is currently underway. Caspar Creek data are split into three phases corresponding to three experiments: Phase 1 (1962–1985) reports on a selection harvest (1971–1973) and initial recovery in the South Fork watershed; Phase 2 (1985–2017) includes clearcut harvesting of ~50% of the North Fork watershed (1985–1992) and recovery; and Phase 3 (2017 onward) corresponds to a second selection harvest in the South Fork watershed with a range of subwatershed harvest intensities (2017–2019) and recovery. All three experiments included harvest-related road-building and relied primarily on measurements of streamflow and sediment delivery from both treated and reference watersheds. Major findings include modest increases in post-harvest peak flows and cumulative flow volumes, post-harvest low flows that initially increased and then decreased 12 to 15 years after harvesting, and the consequences of different yarding techniques and road design on sediment yields. Some of the data for Phase 1 and Phase 2 are available in a USDA Forest Service online archive. The archived data include precipitation, streamflow, suspended sediment concentrations, turbidity, accumulated weir pond sediment volumes, bedload transport rates, water stable isotope data, and geospatial data. Archiving activities are ongoing. Phase 3 data are currently being collected and will be archived after a post-harvest monitoring period. 相似文献
203.
Late Mesoproterozoic rifting in Arctic Canada during Rodinia assembly: impactogens,trans‐continental far‐field stress and zinc mineralisation
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Elizabeth C. Turner Darrel G. F. Long Robert H. Rainbird Joseph A. Petrus Nicole M. Rayner 《地学学报》2016,28(3):188-194
This paper challenges the conventional interpretation of a major, economically important Mesoproterozoic intracratonic rift system as a group of aulacogens, proposing instead that they are rifts that developed in response to far‐field stress caused by continent–continent collision (impactogens) during supercontinent assembly. The tectonostratigraphic evolution of the Bylot basins (Arctic Canada) records dramatic alternations between extensional and compressional stress regimes, precluding an aulacogen interpretation and favouring an impactogen interpretation. New geochronological data (U–Th–Pb whole‐rock depositional age; detrital zircon signatures) provide a record of impactogens that developed in Laurentia's interior as a result of Grenvillian (~1.1 Ga) far‐field stress during assembly of the supercontinent Rodinia. Formation of the world‐class Nanisivik zinc deposit in one of the rifts is temporally associated with the Grenvillian orogeny, and consequently represents both (i) a rare exception to the global pattern of few ore deposits forming during supercontinent episodes, and (ii) a hitherto unrecognised tectonic setting for carbonate‐hosted zinc deposits. 相似文献
204.
Liang Zhang Edom Moges James W. Kirchner Elizabeth Coda Tianchi Liu Adam S. Wymore Zexuan Xu Laurel G. Larsen 《水文研究》2021,35(11):e14429
Comparative hydrology has been hampered by limited availability of geographically extensive, intercompatible monitoring data on comprehensive water balance stores and fluxes. These limitations have, for example, restricted comprehensive assessment of multiple dimensions of wetting and drying related to climate change and hampered understanding of why widespread changes in precipitation extremes are uncorrelated with changes in streamflow extremes. Here, we address this knowledge gap and underlying data gap by developing a new data synthesis product and using that product to detect trends in the frequencies and magnitudes of a comprehensive set of hydroclimatic and hydrologic extremes. CHOSEN (Comprehensive Hydrologic Observatory Sensor Network) is a database of streamflow, soil moisture, and other hydroclimatic and hydrologic variables from 30 study areas across the United States. An accompanying data pipeline provides a reproducible, semi-automated approach for assimilating data from multiple sources, performing quality assurance and control, gap-filling and writing to a standard format. Based on the analysis of extreme events in the CHOSEN dataset, we detected hotspots, characterized by unusually large proportions of monitored variables exhibiting trends, in the Pacific Northwest, New England, Florida and Alaska. Extreme streamflow wetting and drying trends exhibited regional coherence. Drying trends in the Pacific Northwest and Southeast were often associated with trends in soil moisture and precipitation (Pacific Northwest) and evapotranspiration-related variables (Southeast). In contrast, wetting trends in the upper Midwest and the Rocky Mountains showed few univariate associations with other hydroclimatic extremes, but their latitudes and elevations suggested the importance of changing snowmelt characteristics. On the whole, observed trends are incompatible with a ‘drying-in-dry, wetting-in-wet’ paradigm for climate-induced hydrologic changes over land. Our analysis underscores the need for more extensive, longer-term observational data for soil moisture, snow and evapotranspiration. 相似文献
205.
Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory
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Lidiia Iavorivska Elizabeth W. Boyer Jeffrey W. Grimm Matthew P. Miller David R. DeWalle Kenneth J. Davis Margot W. Kaye 《水文研究》2017,31(16):2935-2950
Organic compounds are removed from the atmosphere and deposited to the Earth's surface via precipitation. In this study, we quantified variations of dissolved organic carbon (DOC) in precipitation during storm events at the Shale Hills Critical Zone Observatory, a forested watershed in central Pennsylvania (USA). Precipitation samples were collected consecutively throughout the storm during 13 events, which spanned a range of seasons and synoptic meteorological conditions, including a hurricane. Further, we explored factors that affect the temporal variability by considering relationships of DOC in precipitation with atmospheric and storm characteristics. Concentrations and chemical composition of DOC changed considerably during storms, with the magnitude of change within individual events being comparable or higher than the range of variation in average event composition among events. Although some previous studies observed that concentrations of other elements in precipitation typically decrease over the course of individual storm events, results of this study show that DOC concentrations in precipitation are highly variable. During most storm events, concentrations decreased over time, possibly as a result of washing out of the below‐cloud atmosphere. However, increasing concentrations that were observed in the later stages of some storm events highlight that DOC removal with precipitation is not merely a dilution response. Increases in DOC during events could result from advection of air masses, local emissions during breaks in precipitation, or chemical transformations in the atmosphere that enhance solubility of organic carbon compounds. This work advances understanding of processes occurring during storms that are relevant to studies of atmospheric chemistry, carbon cycling, and ecosystem responses. 相似文献
206.
As tools for collecting data continue to evolve and improve, the information available for research is expanding rapidly. Increasingly, this information is of a spatio‐temporal nature, which enables tracking of phenomena through both space and time. Despite the increasing availability of spatio‐temporal data, however, the methods for processing and analyzing these data are lacking. Existing geocoding techniques are no exception. Geocoding enables the geographic location of people and events to be known and tracked. However, geocoded information is highly generalized and subject to various interpolation errors. In addition, geocoding for spatio‐temporal data is especially challenging because of the inherent dynamism of associated data. This article presents a methodology for geocoding spatio‐temporal data in ArcGIS that utilizes several additional supporting procedures to enhance spatial accuracy, including the use of supplementary land use information, aerial photographs and local knowledge. This hybrid methodology allows for the tracking of phenomenon through space and over time. It is also able to account for reporting inconsistencies, which is a common feature of spatio‐temporal data. The utility of this methodology is demonstrated using an application to spatio‐temporal address records for a highly mobile group of convicted felons in Hamilton County, Ohio. 相似文献
207.
Avellaneda PM Englehardt JD Olascoaga J Babcock EA Brand L Lirman D Rogge WF Solo-Gabriele H Tchobanoglous G 《Marine pollution bulletin》2011,62(10):2157-2169
A relative risk assessment of biosolids disposal alternatives for cruise ships is presented in this paper. The area of study encompasses islands and marine waters of the Caribbean Sea. The objective was to evaluate relative human health and ecological risks of (a) dewatering/incineration, (b) landing the solids for disposal, considering that in some countries land-disposed solids might be discharged in the near-shore environment untreated, and (c) deep ocean disposal. Input to the Bayesian assessment consisted of professional judgment based on available literature and modeling information, data on constituent concentrations in cruise ship biosolids, and simulations of constituent concentrations in Caribbean waters assuming ocean disposal. Results indicate that human health and ecological risks associated with land disposal and shallow ocean disposal are higher than those of the deep ocean disposal and incineration. For incineration, predicted ecological impacts were lower relative to deep ocean disposal before considering potential impacts of carbon emissions. 相似文献
208.
Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp
Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study. 相似文献
209.
Ferretti JA Tran HV Cosgrove E Protonentis J Loftin V Conklin CS Grant RN 《Marine pollution bulletin》2011,62(5):1066-1072
Currently, densities of Enterococcus in marine bathing beach samples are performed using conventional methods which require 24 h to obtain results. Real-time PCR methods are available which can measure results in as little as 3 h. The purpose of this study was to evaluate a more rapid test method for the determination of bacterial contamination in marine bathing beaches to better protect human health. The geometric mean of Enterococcus densities using Enterolert® defined substrate testing and membrane filtration ranged from 5.2 to 150 MPN or CFU/100 mL and corresponding qPCR results ranged from 6.6 to 1785 CCE/100 mL. The regression analysis of these results showed a positive correlation between qPCR and conventional tests with an overall correlation (r) of 0.71. qPCR was found to provide accurate and sensitive estimate of Enterococcus densities and has the potential to be used as a rapid test method for the quantification of Enterococcus in marine waters. 相似文献
210.
We evaluated microbiological water quality in the Pettaquamscutt River (Rhode Island, USA), an estuarine river. Fecal coliform (FC) and enterococci (FE) bacteria, presence of Bifidobacterium adolescentis DNA (indicating human fecal contamination), and optical brightener (OB) fluorescence (associated with laundry detergents) were determined for 14 stations from May to September 2010. Six stations had high counts of FE and FC, and the presence of B. adolescentis DNA and high OB fluorescence indicated human fecal contamination - four had septic systems as likely sources of contamination; the others were in sewered areas. The ability of FC and FE to indicate human fecal contamination was assessed against a positive B. adolescentis test. FC and FE had false positive rates of 25% and 17%, respectively, and false negatives of 44% for FC and 63% for FE. Inclusion of molecular and chemical indicators should improve tracking of human fecal contamination sources in the river. 相似文献