Survival,duration of larval stages,and size of postlarvae of grass shrimp,Palaemonetes pugio,reared from kepone® contaminated and uncontaminated populations in Chesapeake Bay     

Anthony J. Provenzano  Kathleen B. Schmitz  Mark A. Boston 《Estuaries and Coasts》1978,1(4):239-244

Replicate groups of larvae from each of three female grass shrimp,Palaemonetes pugio, collected at each of six sites within Chesapeake Bay were reared in the laboratory to metamorphosis at 25°C, 25 ppt salinity. They were provided with approximately 300Artemia nauplii/larva/day. Sites were selected to provide both suspected Kepone^® contaminated and non-contamined shrimp populations. A sample of eggs, adult females with and without eggs, and newly hatched larvae from each site were analyzed by Virginia Institute of Marine Science for Kepone as were postlarvae obtained through laboratory rearings. Females and eggs from the James River had highest concentrations of Kepone (0.63 and 0.47 ppm, respectively) with samples from the Lafayette River at the mouth of the James River having the second highest levels (0.04 and 0.4 ppm). Concentrations in ovigerous females and eggs in the populations most distant from the James (mouth of Potomac and upper Potomac River) were at or below the limits of detectability (0.001 to 0.015 ppm). In laboratory reared postlarvae from each site, concentrations of Kepone were undetectable. Despite these apparent differences in Kepone concentrations in the various populations we found no significant differences in larval survival, larval duration, or length of post-larvae attributable to site of origin. Highly significant differences in larval duration and size of post-larvae were attributable to parental variation.  相似文献   

Geochemical approach to estimate the quality of water entering abandoned underground coalmines     

Pradeep?Mugunthan  Kathleen?M.?McDonough  David?A.?DzombakEmail author 《Environmental Geology》2004,45(6):769-780

Geochemical modeling was employed to estimate the chemistry of water infiltrating into abandoned underground flooded and unflooded coalmines of the Uniontown syncline, Fayette County, Pennsylvania. This was done to help evaluate factors governing the long-term evolution of coalmine discharge water quality in the Uniontown syncline area. The subsurface structure and lithology was delineated using borehole, mine shaft, and stratigraphic information. Hydrogeologic analyses indicated that most of the recharge to mine voids occurs in the zones of shallow overburden cover of less than 20 m in thickness. The water–rock contact period in the recharge areas of the overburden was estimated to be 5 days or greater for the flooded mines, and a day or less for the unflooded mines. Flow-through reaction-path models were applied to the topsoil and shale–sandstone lithological units identified in the recharge areas. The model predicted water entering the flooded mines at a pH of 6.65, alkalinity of 6.92 mequiv. l^–1 and a total sulfate concentration of 7.33 mM, and the unflooded mines at a pH of 6.68, alkalinity of 6.99 mequiv. l^–1 and a total sulfate concentration of 3.08 mM. The model predictions for the flooded and unflooded mines are consistent with groundwater data from the study site, indicating the usefulness of this approach in evaluating the contribution of overburden chemistry to the evolution of mine discharge quality.  相似文献   

Halogen geochemistry of the McMurdo dry valleys lakes, Antarctica: Clues to the origin of solutes and lake evolution   总被引：1，自引：0，他引：1  

W. Berry Lyons  Kathleen A. Welch  John Olesik  Giles M. Marion 《Geochimica et cosmochimica acta》2005,69(2):305-323

We have determined the halogen and boron concentrations in the ice-covered lakes of Taylor Valley, Antarctica, to better establish the sources of salts and evolutionary histories of these unusual water bodies. In addition, we report on a series of ¹²⁹I measurements that were compared with previous ³⁶Cl data that also help constrain the source of solutes and histories of the lakes. The new data, when put into context of previous work on these systems over the past forty years, allow us to make the following conclusions. The primary source of solutes to Lake Hoare, the youngest of the lakes, is the dissolution of marine aerosols and aeolian salts and the chemical weathering of dust on the glaciers. The geochemistry of Lake Fryxell, the brackish water lake, is primarily dominated by the diffusion from a halite-saturated brine at the sediment-water interface and the recent infilling of the lake by glacier meltwater. These waters have chemical weathering and marine aerosols components. Lake Bonney has two distinct lobes whose hypersaline hypolimnia have different chemistries. Both of the lobes are remnants of ancient marine waters that have been modified by the input of weathering products. This lake has also been modified by periods of cryogenic concentration when solutes have been lost via mineral precipitation. Thus the geochemistry of Lake Bonney owes its unusual geochemistry, in part, to variations in the climate in the Taylor Valley over at least the past 300kyr. The ¹²⁹I data from the Taylor Valley are similar to those from fracture fluids in crystalline rocks from the Northern Hemisphere.  相似文献   

“Traditional” women, “modern” water: Linking gender and commodification in Rajasthan, India     

Kathleen O&#x;Reilly 《Geoforum》2006,37(6):958-972

In this paper, I analyze the connections made between women and water in a Rajasthani drinking water supply project as a significant part of drinking water’s commodification. For development policy makers, water progressing from something free to something valued by price is inevitable when moving economies toward modernity and development. My findings indicate that water is not commodified simply by charging money for it, but through a series of discourses and acts that link it to other “modern” objects and give it value. One of these objects is “women”. I argue that through women’s participation activities that link gender and modernity to new responsibilities and increased mobility for village women involving the clean water supply, a “traditional” Rajasthani woman becomes “modern”. Water, in parallel, becomes “new”, “improved” and worth paying for. Women and water resources are further connected through project staff’s efforts to promote latrines by targeting women as their primary users. The research shows that villagers applied their own meanings to latrines, some of which precluded women using them. This paper fills a gap in feminist political ecology, which often overlooks how gender is created through natural resource interventions, by concerning itself with how new meanings of “water” and “women” are mutually constructed through struggles over water use and its commodification. It contributes to critical development geography literatures by demonstrating that women’s participation approaches to natural resource development act as both constraints and opportunities for village constituents. It examines an under-explored area of gender and water research by tracing village-level struggles over meanings of latrines.  相似文献   

A diatom-based reconstruction of drought intensity, duration, and frequency from Moon Lake, North Dakota: a sub-decadal record of the last 2300 years   总被引：2，自引：0，他引：2  

Kathleen R. Laird  Sherilyn C. Fritz  Brian F. Cumming 《Journal of Paleolimnology》1998,19(2):161-179

Diatom assemblages preserved in sediment cores from closed-basin lakes can provide high-resolution records of past hydrologic and climatic conditions, including long-term patterns in the intensity, duration, and frequency of droughts. At Moon Lake, a closed-basin lake in eastern North Dakota, a comparison of diatom-inferred salinity and the precipitation-based Bhalme-Mooley Drought Index (BMDI) over the last 100 years was highly significant, suggesting that the diatom record contains a sensitive archive of past climatic conditions. A sub-decadal record of inferred salinity for the past 2300 years indicates that extreme droughts of greater intensity than those during the 1930s 'Dust Bowl' were more frequent prior to A.D. 1200. This high frequency of extreme droughts persisted for centuries and was most pronounced from A.D. 200–370, A.D. 700–850 and A.D. 1000–1200. A pronounced shift to generally wetter conditions with less severe droughts of shorter duration occured at A.D. 1200. This abrupt change coincided with the end of the 'Medieval Warm Period' (A.D. 1000–1200) and the onset of the 'Little Ice Age' (A.D. 1300–1850).  相似文献   

Decomposition of saltmeadow cordgrass (Spartina patens) in Louisiana coastal marshes     

A. Lee Foote  Kathleen A. Reynolds 《Estuaries and Coasts》1997,20(3):579-588

In Louisiana, plant production rates and associated decomposition rates may be important in offsetting high rates of land loss and subsidence in organic marsh soils. Decomposition ofSpartina patens shoot and leaf material was studied by using litter bags in mesohaline marshes in the Barataria and Terrebonne basins of coastal Louisiana.Spartina patens decomposed very slowly with an average decay constant of 0.0007, and approximately 50% of the material remained after 2 years in the field. Material at the Barataria site decomposed faster than did Terrebonne material with trend differences apparent during the first 150 days. This difference might be explained by the higher content of phosphorus in the Barataria material or a flooding period experienced by the Barataria bags during their first 10 days of deployment. Nitrogen and carbon content of the plant material studied did not differ between the two basins. We detected no consistent significant differences in decomposition above, at, or below sediment/water level. BecauseS. patens is the dominant plant in these marshes, and because it is so slow to decompose, we believe thatS. patens shoots are an important addition to vertical accretion and, therefore, marsh elevation.  相似文献   

Mercury-binding proteins in the slipper limpet,Crepidula fornicata,exposed to increased soluble mercury     

Florence L. Harrison  Kathleen Watness  David A. Nelson  James E. Miller  Anthony Calabrese 《Estuaries and Coasts》1987,10(1):78-83

Crepidula fornicata were held in a flow-through bioassay system and exposed to sand-filtered seawater to which no soluble mercury (control) was added or to which either 5, 25, or 50 μg 1^?1 soluble Hg was added. At specific intervals during the 16-week experiment, a group of limpets was removed from each tank; one subgroup was exposed for 48 h to high concentrations of Hg, and another was analyzed for Hg-binding proteins by gelpermeation chromatography and spectrometry. Mortality from exposure to Hg in the 48-h acute toxicity tests was related to concentrations of Hg experienced both during the long-term exposure period and the 48-h exposure period. Chronic exposure to low levels of Hg resulted in increased amounts of total Hg in the whole body and in the low-molecular-weight Hg-binding proteins. No evidence was found for increased tolerance to Hg with preexposure.  相似文献   

Isotopic composition of surface-correlated chromium in Apollo 16 lunar soils     

B.Kathleen Kitts  Frank A. Podosek  Joyce C. Brannon  Randy L. Korotev 《Geochimica et cosmochimica acta》2003,67(24):4881-4893

We have analyzed by thermal ionization mass spectrometry (TIMS) the isotopic composition of Cr in five progressive etches of size-sorted plagioclase grains separated from lunar soils 60601 and 62281. Aliquots of the etch solutions were spiked for isotopic dilution (ID) analysis of Cr and Ca. The Ca ID data indicate that the initial etch steps represent dissolution of an average 0.1 to 0.2 μm depth from the grain surfaces, the approximate depth expected for implanted solar wind. The Cr/Ca ratio in the initial etches is several fold higher than that expected for bulk plagioclase composition, but in subsequent etches decreases to approach the bulk value. This indicates a source of Cr extrinsic to the plagioclase grains, surface-correlated and resident in the outermost fraction of a μm, which we provisionally identify as solar wind Cr. The surface-correlated Cr is isotopically anomalous and by conventional TIMS data reduction has approximately 1 permil excess ⁵⁴Cr and half as great excess ⁵³Cr. In successive etches, as the Cr/Ca ratio decreases and approaches the bulk plagioclase value, the magnitude of the apparent anomalies decreases approaching normal composition. If these results do indeed characterize the solar wind, then either the solar wind is enriched in Cr due to spallation in the solar atmosphere, or the Earth and the various parent bodies of the meteorites are isotopically distinct from the Sun and must have formed from slightly different mixes of presolar materials. Alternative interpretations include the possibility that the anomalous Cr is meteoritic rather than solar or that the observed (solar) Cr is normal except for a small admixture of spallation Cr generated on the Moon. We consider these latter possibilities less likely than the solar wind interpretation. However, they cannot be eliminated and remain working hypotheses.  相似文献   

Strontium Isotopic Signatures of the Streams and Lakes of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering in a Polar Climate     

W. B. Lyons  Carmen A. Nezat  Larry V. Benson  Thomas D. Bullen  Elizabeth Y. Graham  Jesicca Kidd  Kathleen A. Welch  James M. Thomas 《Aquatic Geochemistry》2002,8(2):75-95

We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different ⁸⁷Sr/⁸⁶Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system could be either the Cenozoic volcanic rocks that make up a small portion of the till deposited in the valley during the Last Glacial Maximum or from marble derived from the local basement rocks. The more radiogenic ratios from Lake Bonney originate from ancient salt deposits that flow into the lake from Taylor Glacier and the weathering of minerals with more radiogenic Sr isotopic ratios within the tills. The Sr isotopic data from the streams and lakes of Taylor Valley strongly support the notion documented by previous investigators that chemical weathering has been, and is currently, a major process in determining the overall aquatic chemistry of these lakes in this polar desert environment.  相似文献   

Interaction of wind and cold-season hydrologic processes on erosion from complex topography following wildfire in sagebrush steppe     

Samantha P. Vega  C. Jason Williams  Erin S. Brooks  Frederick B. Pierson  Eva K. Strand  Peter R. Robichaud  Robert E. Brown  Mark S. Seyfried  Kathleen A. Lohse  Kayla Glossner  Jennifer L. Pierce  Clay Roehner 《地球表面变化过程与地形》2020,45(4):841-861

Wildfire is a natural component of sagebrush (Artemisia spp.) steppe rangelands that induces temporal shifts in plant community physiognomy, ground surface conditions, and erosion rates. Fire alteration of the vegetation structure and ground cover in these ecosystems commonly amplifies soil losses by wind- and water-driven erosion. Much of the fire-related erosion research for sagebrush steppe has focused on either erosion by wind over gentle terrain or water-driven erosion under high-intensity rainfall on complex topography. However, many sagebrush rangelands are geographically positioned in snow-dominated uplands with complex terrain in which runoff and sediment delivery occur primarily in winter months associated with cold-season hydrology. Current understanding is limited regarding fire effects on the interaction of wind- and cold-season hydrologic-driven erosion processes for these ecosystems. In this study, we evaluated fire impacts on vegetation, ground cover, soils, and erosion across spatial scales at a snow-dominated mountainous sagebrush site over a 2-year period post-fire. Vegetation, ground cover, and soil conditions were assessed at various plot scales (8 m² to 3.42 ha) through standard field measures. Erosion was quantified through a network of silt fences (n = 24) spanning hillslope and side channel or swale areas, ranging from 0.003 to 3.42 ha in size. Sediment delivery at the watershed scale (129 ha) was assessed by suspended sediment samples of streamflow through a drop-box v-notch weir. Wildfire consumed nearly all above-ground live vegetation at the site and resulted in more than 60% bare ground (bare soil, ash, and rock) in the immediate post-fire period. Widespread wind-driven sediment loading of swales was observed over the first month post-fire and extensive snow drifts were formed in these swales each winter season during the study. In the first year, sediment yields from north- and south-facing aspects averaged 0.99–8.62 t ha⁻¹ at the short-hillslope scale (~0.004 ha), 0.02–1.65 t ha⁻¹ at the long-hillslope scale (0.02–0.46 ha), and 0.24–0.71 t ha⁻¹ at the swale scale (0.65–3.42 ha), and watershed scale sediment yield was 2.47 t ha⁻¹. By the second year post fire, foliar cover exceeded 120% across the site, but bare ground remained more than 60%. Sediment yield in the second year was greatly reduced across short- to long-hillslope scales (0.02–0.04 t ha⁻¹), but was similar to first-year measures for swale plots (0.24–0.61 t ha⁻¹) and at the watershed scale (3.05 t ha⁻¹). Nearly all the sediment collected across all spatial scales was delivered during runoff events associated with cold-season hydrologic processes, including rain-on-snow, rain-on-frozen soils, and snowmelt runoff. Approximately 85–99% of annual sediment collected across all silt fence plots each year was from swales. The high levels of sediment delivered across hillslope to watershed scales in this study are attributed to observed preferential loading of fine sediments into swale channels by aeolian processes in the immediate post-fire period and subsequent flushing of these sediments by runoff from cold-season hydrologic processes. Our results suggest that the interaction of aeolian and cold-season hydrologic-driven erosion processes is an important component for consideration in post-fire erosion assessment and prediction and can have profound implications for soil loss from these ecosystems. © 2019 John Wiley & Sons, Ltd.  相似文献