Estuarine and Coastal Habitat Use of Gulf Sturgeon (<Emphasis Type="Italic">Acipenser oxyrinchus desotoi</Emphasis>) in the North-Central Gulf of Mexico

Gulf sturgeon are anadromous, spawning in freshwater and returning to the marine environment to feed. Herein, we document the marine distribution and timing of movement in and out of the marine environment of Gulf sturgeon natal to the Pascagoula and Pearl rivers (MS and LA). From 1999 to 2004, we attached sonic transmitters to 194 fish averaging 151 (MS) to 160 (LA) cm in fork length. We located 56 different Gulf sturgeon in the estuarine or marine environments, some multiple times. Fish were distributed nonrandomly, being found primarily in shallow water (mean = 3.9 m) in barrier island passes. Benthic samples taken at Gulf sturgeon telemetry location sites were dominated by Florida lancelets, sand dollars, annelids, haustoriid amphipods, and mollusks—all documented prey of Gulf sturgeon. Movement into salt water consistently occurred in October and November; movement back into rivers or low salinity estuaries was complete by the end of March.     

Land use and the spatial distribution of perfluoroalkyl compounds as measured in the plasma of bottlenose dolphins (Tursiops truncatus)

The distribution of perfluoroalkyl compounds (PFCs) in the environment is well documented with higher concentrations observed in wildlife located in industrial and urban areas. This study examined the distribution of PFCs in relation to land use using blood samples collected from bottlenose dolphins during capture-release health assessment surveys conducted in Charleston, SC. The study area was partitioned into three subareas (ACW, CHS, and SRE) based upon habitat and land use characteristics. The ACW and CHS subareas are characterized by high degrees of industrial and urban land uses, while the SRE subarea is more residential and characterized by a lower degree of developed land use. Long-term monitoring data from photo-identification surveys were used to group bottlenose dolphins based on their proportions of sightings in the different subareas. Dolphins affiliated with both the ACW and CHS subareas were observed to have significantly higher mean plasma concentrations of perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) than those affiliated with the SRE subarea. Dolphins affiliated with the ACW subarea were found to have a significantly higher mean plasma concentration of PFUnA than those affiliated with the CHS subarea. Further examination of the distribution of the PFCs revealed positive correlations with developed land uses and negative correlations with wetland/marsh land cover. A positive correlation was also observed between PFUnA and agricultural land use. The variability and scale of the observed contaminant burdens have important implications for the conservation and management of living marine resources and illustrates the importance of long-term monitoring of free-ranging wildlife species.     

吐哈盆地煤成烃研究新进展

运用生物标记物及碳同位素等地化参数对吐鲁番 -哈密盆地的原油及其源岩进行了油源对比 |结果将该区原油分为三类 :第一类原油 |根据生标特征分析其具有显著的淡水环境、藻含量低、细菌影响大、C₂₉甾烷含量高、C₃₀4_α- 甲基甾烷低、C₂₄ 四环烷和C₁₉三环烷含量高和碳同位素偏重 (δ13C为 - 25‰~ - 27‰ )的特点 |初步对比结果 |本区西山窑组的煤是该类原油的主要源岩;第二类原油 |富含藻类物质(C₂₇甾烷与C₃₀4_α-甲基甾烷含量较高 ) |该类原油可能来自侏罗系的富藻湖相泥岩;第三类原油 |全油碳同位素δ13C为 - 30‰~ - 32‰ |这类原油的生标反映出其源岩相的特征为缺氧、咸水、中等含藻的湖相沉积 (高含量的伽玛蜡烷和 β_-胡萝卜烷|C₃₅/C₃₄藿烷比值大等 )。     

Epibiont shadowing: a hitherto unrecognized way of preserving soft-bodied fossils

Outlines of soft-bodied sessile epibionts that grew attached to the surfaces of calcareous shells in ancient seas are sometimes preserved by a process termed ‘Epibiont Shadowing’. Processes that altered the surface of the shell were prevented from happening immediately beneath the attached epibiont, leaving a shadow of its attachment site following its death and decay. Microboring around the perimeter of the epibiont by presumed endolithic cyanobacteria gave rise to Endolithic Shadows, and dissolution of the calcareous substrate, maybe beneath larger smothering organisms, produced Solution Shadows of smaller organisms that protected their sites of attachment from such etching effects. Recognition of this type of preservation allows the stratigraphic range of certain soft-bodied groups to be extended. Details of the shadows may yield information about the morphological construction of the groups in question.     

Molecular band variations as a probe of the vertical structure of a Jovian atmosphere

A variational technique is used to compute synthetic spectra for models of cloudy Jovian planetary atmospheres which incorporate abrupt changes in their vertical structure. The dependence of the center-to-limb variations in equivalent widths of molecular bands upon the properties of the various scattering layers in the model is examined. A range of theoretical models are delineated on the basis of their ability to reproduce observational results for the specific case of Jupiter.     

Identifying connections in a fractured rock aquifer using ADFTs

Fractured rock aquifers are difficult to characterize because of their extremely heterogeneous nature. Developing an understanding of fracture network hydraulic properties in these aquifers is difficult and time consuming, and field testing techniques for determining the location and connectivity of fractures in these aquifers are limited. In the Clare Valley, South Australia, well interference is an important issue for a major viticultural area that uses a fractured aquifer. Five fracture sets exist in the aquifer, all dipping > 25 degrees . In this setting, we evaluate the ability of steady-state asymmetric dipole-flow tests (ADFTs) to determine the connections between a test well and a set of piezometers. The procedure involves dividing a test well into two chambers using a single packer and pumping fluid from the upper chamber to the lower chamber. By conducting a series of tests at different packer elevations, an "input" signal is generated in fracture zones connected to the test well. By monitoring the "output" response of the hydraulic dipole field at piezometers, the connectivity of the fractures between the test well and piezometers can be determined. Results indicate the test well used in this study is connected in a complex three-dimensional geometry, with drawdown occurring above and below areas of potentiometric buildup. The ADFT method demonstrates that the aquifer evaluated in this study cannot be modeled effectively on the well scale using continuum flow models.