Assessment of a Sr isotope vital effect (87Sr/86Sr) in marine taxa from Lee Stocking Island, Bahamas     

E. G. Reinhardt  J. Blenkinsop  R. T. Patterson 《Geo-Marine Letters》1998,18(3):241-246

Data from Lee Stocking Island, Bahamas, confirms the hypothesis that there are no vital effects with the uptake of Sr isotopes (⁸⁷Sr/⁸⁶Sr) at the present mass spectrometer resolution [±2×10^?5 (2σ)]. Our data set contains analyses of 40 samples derived from 37 different calcareous taxa inhabiting a wide range of carbonate subenvironments (i.e., reefal, intertidal, supratidal, mangrove). The mean value of our analyses was 0.709179 with a standard deviation of 2.4×10^?5 (2σ) which was very close to the long-term uncertainty of the strontium isotope methodology [±2.0×10^?5 (2σ)] and to the widely reported ⁸⁷Sr/⁸⁶Sr value of seawater, which clusters around 0.709175.  相似文献   

Comparison of granulometric methods and sampling strategies used in marine habitat classification and Ecological Status assessment     

Forde J  Collins PC  Patterson A  Kennedy R 《Marine pollution bulletin》2012,64(5):1018-1028

Sediment particle size analysis (PSA) is routinely used to support benthic macrofaunal community distribution data in habitat mapping and Ecological Status (ES) assessment. No optimal PSA Method to explain variability in multivariate macrofaunal distribution has been identified nor have the effects of changing sampling strategy been examined. Here, we use benthic macrofaunal and PSA grabs from two embayments in the south of Ireland. Four frequently used PSA Methods and two common sampling strategies are applied. A combination of laser particle sizing and wet/dry sieving without peroxide pre-treatment to remove organics was identified as the optimal Method for explaining macrofaunal distributions. ES classifications and EUNIS sediment classification were robust to changes in PSA Method. Fauna and PSA samples returned from the same grab sample significantly decreased macrofaunal variance explained by PSA and caused ES to be classified as lower. Employing the optimal PSA Method and sampling strategy will improve benthic monitoring.  相似文献   

Survey of stable isotope values in Irish surface waters     

Aaron?F.?Diefendorf Email author  William?P.?Patterson 《Journal of Paleolimnology》2005,34(2):257-269

We present a study of the spatial distribution of δ¹⁸O and δD values of lake and river waters from 144 locations in Ireland. Before we can gain a better understanding of paleoclimate records derived from lacustrine carbonate minerals we must understand mechanisms that produce variation in isotope values of modern surface waters. The focus of this study is to provide insight into the behavior of lakes and rivers in Ireland, including source, recycling and loss through evapotranspiration. The short duration of sampling in this project provides a snapshot of modern isotope variability to be applied towards long-term climate change in Ireland and provides a basis of comparison for other proxy records.Electronic supplementary material to this article is available at and accessible for authorized users.  相似文献   

Discriminant analysis applied to aerial radiometric data and its application to Uranium favorability in South Texas     

David A. Patterson  Fredric L. Pirkle  Mark E. Johnson  Thomas R. Bement  Newton K. Stablein  C. Kay Jackson 《Mathematical Geology》1981,13(6):535-568

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PENSION FUND INVESTMENTS: AN INITIAL GEOGRAPHIC ASSESSMENT*     

Howard A. Botts  John G. Patterson 《The Professional geographer》1987,39(4):416-427

Despite the importance of interregional shifts of capital in contributing to patterns of regional development, pension funds, a large and growing source of capital in the world, have received limited empirical investigation by geographers. An initial assessment of the geographic impact of selected pension fund investments controlled by the State of Wisconsin Investment Board (SWIB) is presented. A simple investment allocation model is employed to address several research questions. Findings indicate changes in investment categories over time and suggest interregional investment shifts that fail to fall neatly along Sunbelt/Snowbelt lines. Recent SWIB investments may be undercutting the state's competitive position with other – and in some cases Sunbelt – states.  相似文献   

Arcellaceans (thecamoebians): new tools for monitoring long- and short-term changes in lake bottom acidity   总被引：6，自引：0，他引：6  

A. Kumar  R. T. Patterson 《Environmental Geology》2000,39(6):689-697

 James Lake, northeastern Ontario, Canada, has been impacted by the dumping of waste rock from a pyrite mine. High levels of Fe, Al and SO₄, and low pH (2.0–5.5) are recorded in the lake. Lake configuration and current direction result in contaminated areas being restricted to the southwestern portion of the lake. Near neutral pH and low metal levels are recorded elsewhere. Analysis of arcellacean faunas from the lake indicate that one species, Arcella vulgaris, is able to thrive in even the most hostile areas of the lake. The absence of other arcellaceans indicative of contaminated substrates in higher pH lakes, such as centropyxids and Difflugia protaeiformis strains, suggests that pH is the dominant control on the distribution of this assemblage. Analysis of arcellaceans from a core at the site indicates that contamination and acidification (pH values <5.5) problems in James Lake have existed for at least 1300 years, clearly predating mining activity. Prior to that time high proportions of centropyxid species indicate less acid conditions (pH>5.5) prevailed, but a stressed environment existed for several thousand years. The recognition that Arcellacean faunas can now be used to characterize industrially, and naturally contaminated environments of both low and high pH, provides an important new paleolimnological tool. Received: 6 October 1998 · Accepted: 23 February 1999  相似文献   

The effects of disproportional load contributions on quantifying vegetated filter strip sediment trapping efficiencies     

Heather?E.?GallEmail authorView author&#;s OrcID profile  Daniel?Schultz  Tamie L.?Veith  Sarah C.?Goslee  Alfonso?Mejia  Ciaran J.?Harman  Cibin?Raj  Paul?H.?Patterson 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(8):2369-2380

Vegetated filter strips (VFSs) are a best management practice (BMP) commonly implemented adjacent to row-cropped fields to trap overland transport of sediment and other constituents present in agricultural runoff. Although they have been widely adopted, insufficient data exist to understand their short and long-term effectiveness. High inter-event variability in performance has been observed, yet the majority of studies report average removal efficiencies over observed or simulated events, ignoring the disproportional effects of loads into and out of VFSs over longer periods of time. We argue that due to positively correlated sediment concentration-discharge relationships, disproportional contribution of runoff events transporting sediment over the course of a year (i.e., temporal inequality), decreased performance with increasing flow rates, and effects of antecedent moisture condition, VFS removal efficiencies over annual time scales may be significantly lower than reported per-event averages. By applying a stochastic approach, we investigated the extent of disparity between reporting average efficiencies from each runoff event over the course of 1 year versus the total annual load reduction. Additionally, we examined the effects of soil texture, concentration-discharge relationship, and VFS slope in contributing to this disparity, with the goal of revealing potential errors that may be incurred by ignoring the effects of temporal inequality in quantifying VFS performance. Simulation results suggest that ignoring temporal inequality can lead to overestimation of annual performance by as little as < 2% and to as much as > 20%, with the greatest disparities observed for soils with high clay content.  相似文献