Lost Foraging Opportunities for East Asian Hunter‐Gatherers Due to Rising Sea Level Since the Last Glacial Maximum     

Jade d'Alpoim Guedes  Jacqueline Austermann  Jerry X. Mitrovica 《Geoarchaeology》2016,31(4):255-266

This paper explores how changes in sea level and biome distribution may have affected the habitats occupied by hunter‐gatherers in East Asia. Using a model‐based reconstruction of changing sea level from the Last Glacial Maximum (LGM) to present day, our analysis reveals that the exposure of a large continental shelf during the LGM sea level lowstand created a wealth of wooded, estuarine, and coastal biomes that could have been exploited intensively by Late Pleistocene hunter‐gatherers. Models explaining hunter‐gatherer subsistence changes and migrations in this period should take into account the large area that has been lost to rising sea level since the LGM.  相似文献   

A NUMERICAL EVALUATION OF SOME FLORIDA SPODOSOLS     

A. Goldin  J. Edmonds 《自然地理学》2013,34(3):242-252

The POD Index, a numerical index of soil classification developed by Schaetzl and Mokma (1988) in the mesic to cryic temperature regimes of northern North America, was applied to 425 pedons in Florida to test its utility for soils in thermic and hyperthermic temperature regimes. One purpose of the POD Index is to permit approximate classification of Spodosols and similar soils in the field using soil color and morphology (horizonation) alone, without resorting to chemical analysis. In this study, a POD Index threshold value of 7 separated Florida Spodosols from non-Spodosols about 88% of the time. This study, therefore, extends the utility of the POD Index for differentiating Spodosols from non-Spodosols into the hyperthermic temperature regimes. [Key words: soils, spodic horizon, color, hyperthermic temperature regime, thermic temperature regime, POD Index.]  相似文献   

Centennial records of lead contamination in northern Atlantic bivalves (Arctica islandica)     

Krause-Nehring J  Brey T  Thorrold SR 《Marine pollution bulletin》2012,64(2):233-240

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.  相似文献   

Geochronology of Quaternary glaciations from the tropical Cordillera Huayhuash, Peru     

Sarah R. Hall  Daniel L. Farber  Joan M. Ramage  Donald T. Rodbell  Robert C. Finkel  Jacqueline A. Smith  Bryan G. Mark  Christopher Kassel 《Quaternary Science Reviews》2009,28(25-26):2991-3009

The Cordillera Huayhuash in the central Peruvian Andes (10.3°S, 76.9°W) is an ideal mountain range in which to study regional climate through variations in paleoglacier extents. The range trends nearly north-south with modern glaciers confined to peaks >4800 m a.s.l. Geomorphology and geochronology in the nearby Cordillera Blanca and Junin Plain reveal that the Peruvian Andes preserve a detailed record of tropical glaciation. Here, we use ASTER imagery, aerial photographs, and GPS to map and date glacial features in both the western and eastern drainages of the Cordillera Huayhuash. We have used in situ produced cosmogenic ¹⁰Be concentrations in quartz bearing erratics on moraine crests and ice-polished bedrock surfaces to develop an exposure age chronology for Pleistocene glaciation within the range. We have also collected sediment cores from moraine-dammed lakes and bogs to provide limiting ¹⁴C ages for glacial deposits. In contrast to the ranges to the north and south, most glacial features within the Cordillera Huayhuash are Lateglacial in age, however we have identified features with ages that span 0.2 to 38 ka with moraine sets marking the onset of glacier retreat at 0.3 ka, 9–10 ka, 13–14 ka, 20–22 ka, and >26 ka. The range displays a pronounced east-west variation in maximum down-valley distance from the headwall of moraine crests with considerably longer paleoglaciers in the eastern drainages. Importantly, Lateglacial paleoglaciers reached a terminal elevation of 4000 m a.s.l. on both sides of the Cordillera Huayhuash; suggesting that temperature may have been a dominant factor in controlling the maximum glacier extent. We suggest that valley morphology, specifically valley slope, strongly influences down-valley distance to the maximum glacier extent and potential for moraine preservation. While regionally there is an extensive record of older (>50 ka) advances to the north (Cordillera Blanca) and to the south (Junin region), the apparent lack of old moraines in this locality may be explained by the confined morphology of the Cordillera Huayhuash valleys that has inhibited the preservation of older glacial geomorphic features.  相似文献   

FracKfinder: A MATLAB Toolbox for Computing Three-Dimensional Hydraulic Conductivity Tensors for Fractured Porous Media     

Nathan L. Young  Jacqueline E. Reber  William W. Simpkins 《Ground water》2019,57(1):75-80

Fractures in porous media have been documented extensively. However, they are often omitted from groundwater flow and mass transport models due to a lack of data on fracture hydraulic properties and the computational burden of simulating fractures explicitly in large model domains. We present a MATLAB toolbox, FracKfinder, that automates HydroGeoSphere (HGS), a variably saturated, control volume finite-element model, to simulate an ensemble of discrete fracture network (DFN) flow experiments on a single cubic model mesh containing a stochastically generated fracture network. Because DFN simulations in HGS can simulate flow in both a porous media and a fracture domain, this toolbox computes tensors for both the matrix and fractures of a porous medium. Each model in the ensemble represents a different orientation of the hydraulic gradient, thus minimizing the likelihood that a single hydraulic gradient orientation will dominate the tensor computation. Linear regression on matrices containing the computed three-dimensional hydraulic conductivity (K) values from each rotation of the hydraulic gradient is used to compute the K tensors. This approach shows that the hydraulic behavior of fracture networks can be simulated where fracture hydraulic data are limited. Simulation of a bromide tracer experiment using K tensors computed with FracKfinder in HGS demonstrates good agreement with a previous large-column, laboratory study. The toolbox provides a potential pathway to upscale groundwater flow and mass transport processes in fractured media to larger scales.  相似文献   

Impacts of seawater desalination on the giant Australian cuttlefish Sepia apama in the upper Spencer Gulf, South Australia     

Jacqueline L. Dupavillon  Bronwyn M. Gillanders   《Marine environmental research》2009,67(4-5):207-218

With seawater desalination expanding rapidly, it is important that ecological studies are undertaken to determine the effects of brine discharge on the marine species in the area. The abundance of giant Australian cuttlefish (Sepia apama, Gray 1849) eggs and environmental data were recorded at nine sites near Point Lowly, Spencer Gulf, South Australia, an area where the largest desalination plant in the Southern hemisphere is proposed. In addition, the effects of different concentrations of desalination brine on the growth, survival and condition of cuttlefish embryos were investigated. The primary egg-laying sites for the cuttlefish were in the vicinity of Stony Point (sites 4 and 3) and the area with the least egg abundance was on the eastern and western areas around Point Lowly (sites 9 and 7) where no eggs were found. The survival of embryos decreased with an increase in salinity, with no embryos surviving to full term in salinities greater than 50‰. Mean weight and mantle length also decreased with increasing salinity. Besides elevated salinity, the brine also had increased concentrations of Ba, Ca, K, Sr and Mg relative to water near Point Lowly. Brine discharge from seawater desalination poses a potential threat to the unique spawning aggregation of the giant Australian cuttlefish, in the upper Spencer Gulf, South Australia.  相似文献   

Aggregate performance in managing marine ecosystems of 53 maritime countries     

Jacqueline Alder  Sarika Cullis-Suzuki  Vasiliki Karpouzi  Kristin Kaschner  Suzanne Mondoux  Wilf Swartz  Pablo Trujillo  Reg Watson  Daniel Pauly 《Marine Policy》2010

Fourteen indicators of marine living resource management performance by country, reflecting both their intention to sustainably use the resource within their Exclusive Economic Zones and the effectiveness of their policies, were developed and the performances of 53 maritime countries were assessed. Four rankings of the countries, which jointly account for over 95 percent of the world's marine fisheries landings, are presented here as aggregated scores of the fourteen indicators, using different schemes for weighting the indicators, each reflective of the management preferences identified by the Global Environment Outlook 4 (GEO4) future development scenarios: Market First; Policy First; Security First; and Sustainability First. The resulting rankings differed substantially between the weighting schemes for the top performing countries but less so for the countries performing poorly.  相似文献   

Long-term benthic responses to sustained disturbance by aggregate extraction in an area off the east coast of the United Kingdom     

Christopher R.S. Barrio Froján  Siân E. BoydKeith M. Cooper  Jacqueline D. EggletonSuzanne Ware 《Estuarine, Coastal and Shelf Science》2008

The temporal variability of benthic assemblages inhabiting offshore gravel deposits in the North Sea is poorly known, as purpose-collected long-term data sets have until recently been non-existent. It has therefore proved difficult to understand the stability and resilience of these benthic ecosystems after disturbance caused by the extraction of aggregates on an industrial scale. The present investigation examines an 8-year time series of data collected in and around an active commercial aggregate extraction site off the east coast of the United Kingdom. Both physical and biological data sets suggest a distinct yet localised effect after sustained gravel extraction, with impacted sediments generally appearing more physically homogeneous and faunistically impoverished than undisturbed sediments. Although inter-annual variability of selected assemblage metrics was reduced in disturbed sediments, differences in some assemblage metrics became significant between years. Despite such observations, significant impacts to the benthos in any given year were not sustained for long. However, the magnitude of impact in almost every year would be enough to merit remedial intervention based on an existing model of measuring acceptable levels of disturbance as a result of organic enrichment. Caution must be exercised in making any such recommendations, especially as there are presently no models specifically designed to assess the degree of acceptable disturbance from aggregate extraction. This study not only highlights the importance of and need for long-term data sets in order to better understand the difference between natural and human-induced variability in benthic assemblages, but also emphasises the need to develop more relevant monitoring tools to better manage the activities of the marine aggregate extraction industry.  相似文献   

Effects of Olestra on Organic and Solids Removal in Septic Tanks     

Drew C. McAvoy  Jacqueline A. Greff  D. Ronald Webb  Greg S. Allgood 《Ground Water Monitoring & Remediation》1998,18(4):131-138

A field study was conducted to examine the fate and potential effects of olestra, a non-caloric fat replacer, in septic tanks. The study compared the performance of parallel septic tanks, which were led domestic waste water with liquid and solid forms of olestra, against a control tank receiving waste water without olestra. Results showed that 36 g/d of olestra dosed to the tanks (a three-fold exaggeration of expected loadings) had no adverse effect on system operation (based on visual observations and sludge accumulation) or performance (based on removal of organic content and solids) over a six-month period. Removal efficiencies for total suspended solids (TSS), carbonaceous biochemical oxygen demand (CBOD), and chemical oxygen demand (COD) were not significantly different (p<0.05) in the olestra tanks when compared to the control tank. In addition, a relatively small amount of the total olestra added (3 to 6%) was recovered in the septic tank effluents over the course of the study. Accumulation of tank solids was not affected as measured sludge levels in the tank at the middle and end of the study showed no difference between the olestra dosed tanks and the control tank.  相似文献   

CALCULATION OF AIR-MASS FACTORS FOR O₃          下载免费PDF全文

Chen Hongbin  Wang Pucai  Jacqueline Lenoble 《Acta Meteorologica Sinica》1998,12(4):425-428

In conversion of the integrated slant column amount of atmospheric ozone(O₃) measured by the ground-based spectrometer technique during twilight to the vertical quantity,the air-mass factor(AMF) is an important parameter.In this work,calculations of AMF for ozone were performed for different atmospheres.It is shown that the O₃ AMF has seasonal variations with the minimum at the beginning of spring and the maximum in summer due to the seasonal change in the vertical distributions of O₃.A parameterization relation is obtained between O₃ AMF and optical thickness of stratospheric volcanic aerosols based on the Monte-Carlo radiative transfer simulations.  相似文献