The use of steroid markers to assess sewage contamination of the Black Sea     

Readman JW  Fillmann G  Tolosa I  Bartocci J  Mee LD 《Marine pollution bulletin》2005,50(3):310-318

Analyses of faecal steroids in coastal sediments taken from throughout the Black Sea indicate chronic sewage contamination at some locations. These include Sochi, where concentrations of coprostanol up to 5400 ng g(-1) (dry wt) were recorded, and in the coastal areas adjacent to the Danube delta (2600 ng g(-1) dry wt). Comparatively high values of 5beta/(5beta+5alpha) isomeric ratios of cholestan-3-ol and cholestan-3-one are reported at these locations and are characteristic of sediments contaminated with sewage. Lower concentrations of coprostanol are reported for Bosphorus sediments (12-440 ng g(-1) dry wt) and in the region of Odessa (130-290 ng g(-1) dry wt). Isomeric ratios at these locations also confirm sewage as a significant contributor to steroids in the Bosphorus, but lower values of the ratios indicate only minor sewage inputs in Odessa. In contrast, steroid concentrations and compositions from most Ukrainian sites are characteristic of uncontaminated environments. To place these results into perspective, the range in levels of coprostanol in the Black Sea sediments compares to the lower to mid-range of concentrations reported for coastal sediments on a world-wide basis, with Black Sea sedimentary levels substantially below those previously reported for heavily impacted sites.  相似文献   

A demographic approach to monitoring the health of coral reefs     

Smith LD  Devlin M  Haynes D  Gilmour JP 《Marine pollution bulletin》2005,51(1-4):399-407

Inshore coral reefs adjacent to the wet tropics in North Queensland, Australia, are regularly exposed to flood plumes from coastal river systems. Changes in the nature of these plumes have been linked to the declining health of coral reefs in the region. The effect of flood plumes on the health of inshore corals was investigated by quantifying aspects of the demography of populations of corymbose and digitate Acropora at three groups of Island reefs along a gradient of exposure and decreasing water quality (High Island >Frankland's >Fitzroy). The size-structures of colonies, the rates of sexual recruitment, and the growth and survival of juveniles, all varied among the Island reefs. Juvenile and adult sized colonies were far more abundant at the Fitzroy Island reefs, than at the High or Frankland Island reefs that were more exposed to flood plumes. Additionally, there were up to eight times as many sexual recruits at the Fitzroy Island reefs, compared with the High Island reefs. However, the rates of growth and survival of the juvenile sized corals at the Fitzroy Island reefs were lower than at the more exposed reefs. The comparatively low abundance of adult corals at the exposed reefs is most likely due to their histories of disturbance from crown-of-thorns and coral bleaching, but the lack of subsequent recovery due to their low levels of larval recruitment. If a stock-recruitment relationship is typical for these groups of reefs, then the low rates of recruitment may be linked to the low density of adult colonies. Alternately, direct or indirect effects of chronic exposure to poor water quality may have resulted in less suitable substrata for larval settlement. We discuss these results and provide examples of how information about population structure and dynamics can be used in simple matrix models to quantify the current and future health of populations of corals under various scenarios.  相似文献   

Hepatic 7-ethoxyresorufin O-deethylase activity in eel (Anguilla anguilla) from the Thames Estuary and comparisons with other United Kingdom Estuaries     

Doyotte A  Mitchelmore CL  Ronisz D  McEvoy J  Livingstone DR  Peters LD 《Marine pollution bulletin》2001,42(12):1313-1322

Hepatic microsomal 7-ethoxyresorufin O-deethylase (EROD) activities (indicative of exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs)) were measured in eel Anguilla anguilla from the Thames Estuary. Fish were collected from up to 13 sites during November 1997, May and August 1998 and October 1999. Throughout this period no clear seasonal variation could be identified at every site along the Thames. However, during the summer months, fish sampled from sites in the middle to the upper estuary (Woolwich, Greenhithe and West Thurrock) reported up to 3-fold higher EROD activities compared to sites either at the upper reaches (Richmond and Brentford) at the same time of the year, or fish sampled in winter, along the entire length of the estuary. A laboratory exposure experiment demonstrated a 3-fold elevation of EROD activity 2 days after injection with β-naphthoflavone (β-NF). However, higher levels of activity could be determined in fish sampled from the Weston canal near the Merseyside. The lowest levels of A. anguilla EROD activity were observed in fish sampled from the upper reaches of the River Tamar, Devon, and were comparable to activities determined in fish from the Wear and Humber estuaries. A. anguilla sampled along the Thames, Tyne and Tees estuaries reported between 2.5- and 7-fold higher EROD activities compared to fish collected from the Tamar. These results indicate that a low to moderate induction of A. anguilla CYP1A had occurred (indicative of low to moderate exposure to PAHs and planar PCBs) in fish collected from the Thames, Tyne, Wear, Tees, Humber and Tamar estuaries. However, the highest level of EROD activity was observed in fish from the Weston Canal (Merseyside).  相似文献   

氢化物发生直流等离子体原子发射光谱法测定微量锡：L—胱氨酸减少干扰     

Brin.  LD 漆亮 《地质地球化学》1991,(1):64-68

  相似文献   

FGCC对Ashtech XⅡ—LDGPS卫星测定系统及其处理软件...     

Hoth.  LD 郑国忠 《测绘译丛》1992,(2):13-18

  相似文献   

Homochirality as the signature of life: the SETH Cigar     

MacDermott AJ  Barron LD  Brack A  Buhse T  Drake AF  Emery R  Gottarelli G  Greenberg JM  Haberle R  Hegstrom RA  Hobbs K  Kondepudi DK  McKay C  Moorbath S  Raulin F  Sandford M  Schwartzman DW  Thiemann WH  Tranter GE  Zarnecki JC 《Planetary and Space Science》1996,44(11):1441-1446

A characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. It is therefore suggested that a search for extra-terrestrial life can be approached as a Search for Extra-Terrestrial Homochirality (SETH). A novel miniaturized space polarimeter, called the SETH Cigar, is described which could he used to detect optical rotation as the homochiral signature of life on other planets. Moving parts are avoided by replacing the normal rotating polarizer by multiple fixed polarizers at different angles as in the eye of the bee. It is believed that homochirality will be found in the subsurface layers on Mars as a relic of extinct life.  相似文献   

Anaerobic biodegradation of TCE in laboratory columns of fractured saprolite     

Lenczewski ME  McKay LD  Layton A 《Ground water》2004,42(4):534-541

An experiment was conducted to determine if biodegradation of trichloroethylene (TCE) can occur in previously uncontaminated ground water in saturated fractured saprolite (highly weathered material derived from sedimentary rocks). Two undisturbed columns (0.23 m diameter by 0.25 m long) of fractured saprolite were collected from approximately 2 m depth at an uncontaminated site on the Oak Ridge Reservation, Oak Ridge, Tennessee. Natural, uncontaminated ground water from the site, which was degassed and spiked with dissolved phase TCE, was continuously pumped through one column containing the natural microbial communities (the biotic column). In a second column, the microorganisms were inhibited and the dissolved phase TCE was added under aerobic conditions (dissolved oxygen conditions > 2 ppm). In effluent from the biotic column, reducing conditions rapidly developed and evidence of anaerobic biodegradation of TCE, by the production of cDCE, first appeared approximately 31 days after addition of TCE. Reductive dechlorination of TCE occurred after iron-reducing conditions were established and about the same time that sulfate reduction began. There was no evidence of methanogenesis. Analyses using polymerase chain reaction with specific primers sets detected the bacteria Geothrix, Geobacter, and Desulfococcus-Desulfonema-Desulfosarcina in the effluent of the biotic column, but no methanogens. The presence of these bacteria is consistent with iron- and sulfate-reducing conditions. In the inhibited column, there were no indicators of TCE degradation. Natural organic matter that occurs in the saprolite and ground water at the site is the most likely primary electron donor for supporting reductive dechlorination of TCE. The relatively rapid appearance of indicators of TCE dechlorination suggests that these processes may occur even in settings where low oxygen conditions occur seasonally due to changes in the water table.  相似文献   

In vitro mechanistic differences in benzo[a]pyrene-DNA adduct formation using fish liver and mussel digestive gland microsomal activating systems   总被引：2，自引：0，他引：2  

Peters LD  Telli-Karakoç F  Hewer A  Phillips DH 《Marine environmental research》2002,54(3-5):499-503

Turbot (Scophthalmus maximus) and mussel (Mytilus edulis) microsomes were incubated with DNA to examine if microsomal in vitro metabolism of BaP could result in DNA adducts detected by 32P-postlabelling. Turbot DNA was incubated with benzo[a]pyrene (BaP), NADPH and microsomal activating systems prepared from either livers of unexposed turbot, turbot exposed to BaP or beta-naphthoflavone (beta-NF) or digestive glands from mussels. The beta-NF activating system generated the highest levels of DNA adducts detected in this study (451.7 adducts per 10(8) nucleotides) and were distributed in three discrete adduct TLC spots, one of which (97% of the total adducts) co-migrated with the 32P-postlabelled BaP 7,8-diol, 9,10-epoxide-N2-guanine adduct. Fewer adducts (P < 0.05) were generated by BaP-induced microsomes (9.4-30.6 adducts per 108 nucleotides) but levels were higher (P <0.05) than those generated from untreated fish (3.5 adducts per 10(8) nucleotides). Co-incubation with 500 microM alpha-naphthoflavone (alpha-NF) resulted in 97-99% inhibition in adduct formation implicating cytochrome P450-dependent (CYP) bioactivation however there was some evidence for carry over of BaP in the liver microsomal preparations from BaP injected fish. In contrast to the fish activating systems, no DNA adducts were observed when mussel microsomes were incubated with BaP, DNA and NADPH.  相似文献   

碎波带和海滩地貌动力变化性综述     

Wrig.  LD 陈子Shen 《南海研究与开发》1993,(2):65-72

  相似文献   

北大西洋（DSDP552A站位）的火山灰层是一种地层工具吗？     

Haas.  LD 石海元 《海洋地质译丛》1989,(6):62-65,81

  相似文献