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Chromophoric dissolved organic matter (CDOM) spectral absorption, dissolved organic carbon (DOC) concentration, and the particulate fraction of inorganic (PIM) and organic matter (POM) were measured in Louisiana coastal waters at Vermilion, Atchafalaya, Terrebonne, Barataria, and Mississippi River locations, in 2007-2008. The range of CDOM was 0.092 m−1 at Barataria in June 2008 to 11.225 m−1 at Mississippi in February 2008. An indicator of organic matter quality was predicted by the spectral slope of absorption coefficients from 350 to 412 nm which was between 0.0087 m−1 at Mississippi in May 2008 and 0.0261 m−1 at Barataria in June 2008. CDOM was the dominant component of light attenuation at Terrebonne and Barataria. Detritus and CDOM were the primary components of light attenuation at Vermilion, Atchafalaya, and Mississippi. DOC ranged between 65 and 1235 μM. PIM ranged between 1.1 and 426.3 mg L−1 and POM was between 0.3 and 49.6 mg L−1. 相似文献
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Keogh SM Cournane S León Vintró L McGee EJ Mitchell PI 《Marine pollution bulletin》2011,62(4):696-700
Radiocarbon levels were recorded in Fucus vesiculosus samples collected on a monthly basis over a three-year period at a site on the east coast of Ireland. The resulting data was analysed using a numerical model which estimates the transit times from the Sellafield plant to the sampling location, and the mean availability time of 14C in seaweed. With the inclusion of a model parameter allowing for seasonal variability in uptake by the Fucus, good correlation was observed between the predicted and measured concentrations. Future temporal trends of 14C Fucus concentrations along the eastern Irish coastline were modelled with the application of three possible prospective discharge scenarios, predicting 14C Fucus concentrations to reduce to ambient background levels within 2.5-years of discharges being set to zero. Such projections may prove helpful in assessing the consequences of discharge management and policy making in the context of the OSPAR convention. 相似文献
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Expression of superoxide dismutase (SOD) genes from the copper-exposed polychaete, Neanthes succinea
To evaluate the superoxide dismutase (SOD) genes as a potential indicator of environmental stress, we cloned and sequenced the full-length cDNA of a Cu/Zn-SOD and Mn-SOD genes from the marine polychaete, Neanthes succinea. Ns-Cu/Zn- and Mn-SOD expression was measured using quantitative real-time RT-PCR in response to the oxidative stress induced by copper in the form of CuCl2. Ns-Cu/Zn-SOD expression increased in a dose dependent manner but the increase of Mn-SOD expression was evident only at a high concentration of copper. Particularly, Ns-Mn-SOD dramatically increased in the 72 μg/L CuCl2-exposed groups, indicating that both Ns-SOD genes were induced by copper exposure. These results suggest that Ns-Cu/Zn- and Ns-Mn-SOD would play important roles in the detoxification of cellular oxidative stresses in the polychaete, N. succinea. Furthermore, as part of field work, the marine polychaete, N. succineaCu/Zn-SOD mRNA collected from the polluted area was accordingly upregulated in expression but not for NS-Mn-SOD. 相似文献
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Cultivable magnetotactic bacteria (MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic
studies. However, a cold-stored MTB strain, such as Magnetospirillum magneticum AMB-1, often loses its ability to synthesize magnetosomes and consequently fails to sense the external magnetic field. It
is therefore important to quickly recover vigorous bacteria cells that highly capable of magnetosome producing. In this study,
a modified capillary magnetic separation system was designed to recover a deteriorating strain of Magnetospirillum magneticum AMB-1 that long-term cold-stored in a refrigerator. The results show that all cells obtained after a 3-cycle treatment were
vigorous and had the ability to produce magnetosomes. Moreover, the 3rd-cycle recovered cells were able to form more magnetosome crystals. Compared with the colony formation method, this new method
is time-saving, easily operated, and more efficient for recovering vigorous MTB cells. 相似文献
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Polychaetes are suitable organisms for evaluation of impact of sediment pollution. We evaluated toxicity of cadmium and copper and measured metallothionein-like proteins (MTLPs) in the polychaete Perinereis nuntia. At the same concentration ranges copper was unexpectedly more toxic than cadmium. Copper also caused no significant increase in MTLPs in the polychaetes. When P. nuntia and another polychaete species, Cirratulus cirratus were cultured in the contaminated sediments collected from Lake Sihwa (Korea), a high mortality of 80% was observed on day 6 in P. nuntia in the sediment with the highest metal concentration. However, no mortality was observed up to 35 days in C. cirratus in any sediment. MTLP contents between two species also varied. These findings suggest that MTLP induction response in the polychaetes varies with the metal type and species and it may be used as a biomarker of sediment pollution in the polychaetes after further validation and field trials. 相似文献
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黄铁矿热转化矿物相变过程的岩石磁学研究 总被引:2,自引:0,他引:2
对天然黄铁矿样品在氩气和空气环境中受热发生的矿物相变过程进行了系统的岩石磁学研究,结果表明:氩气环境(还原环境)下,黄铁矿受热分解转化的产物是磁黄铁矿,其粒度为单畴,矫顽力和剩磁矫顽力分别约为20和30mT,它在还原环境中是稳定的.而空气环境(氧化环境)中黄铁矿受热分解、转化后的最终产物为单畴赤铁矿,FORC图显示其矫顽力高达1400mT,相应的热转化序列为:黄铁矿→磁黄铁矿→磁铁矿→赤铁矿.上述结果对于理解还原环境沉积物的磁性、岩石次生化学剩磁和陨石磁学性质都具有重要参考意义. 相似文献