On the use of IPCC-class models to assess the impact of climate on Living Marine Resources

The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent years with the availability of climate model simulations contributed to the assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Collaboration between climate and LMR scientists and shared understanding of critical challenges for such applications are essential for developing robust projections of climate impacts on LMRs. This paper assesses present approaches for generating projections of climate impacts on LMRs using IPCC-class climate models, recommends practices that should be followed for these applications, and identifies priority developments that could improve current projections. Understanding of the climate system and its representation within climate models has progressed to a point where many climate model outputs can now be used effectively to make LMR projections. However, uncertainty in climate model projections (particularly biases and inter-model spread at regional to local scales), coarse climate model resolution, and the uncertainty and potential complexity of the mechanisms underlying the response of LMRs to climate limit the robustness and precision of LMR projections. A variety of techniques including the analysis of multi-model ensembles, bias corrections, and statistical and dynamical downscaling can ameliorate some limitations, though the assumptions underlying these approaches and the sensitivity of results to their application must be assessed for each application. Developments in LMR science that could improve current projections of climate impacts on LMRs include improved understanding of the multi-scale mechanisms that link climate and LMRs and better representations of these mechanisms within more holistic LMR models. These developments require a strong baseline of field and laboratory observations including long time series and measurements over the broad range of spatial and temporal scales over which LMRs and climate interact. Priority developments for IPCC-class climate models include improved model accuracy (particularly at regional and local scales), inter-annual to decadal-scale predictions, and the continued development of earth system models capable of simulating the evolution of both the physical climate system and biosphere. Efforts to address these issues should occur in parallel and be informed by the continued application of existing climate and LMR models.     

Experimental study on reduction of U (Ⅵ) by an anaerobic bacterium, Shewanella putrefaciens: Application to sandstone-hosted interlayer oxidation-zone type uranium deposits, China

An experimental study on reduction of U (Ⅵ) by anaerobic bacteria, Shewane//a putrefaciens, is first reported here in China. The experimental conditions were: 35℃ and pH =7.0-7.4, corresponding to a physicochemical environments in which the sandstone-hosted interlayer oxidation-zone type uranium deposit formed in Northwest China's Xinjiang. Bacteria adopted in the present experiment, Shewanella putrefaciens, occur extensively in natural environment. Our study shows that nano-crystal precipitates of uraninite quickly occurred on the surface of the cells within one week. It was found that the pitchblende was characterized by a random arrangement of uraninite nanocrystals (2-4 nm) in it, significantly different from natural pitchblende in which uraninite nanocrystals are arranged in order. Finally, a possible mechanism of uranium biomineralization by microorganisms in the deposits is discussed. Our investigation may supply a technical train of thoughts for bioremediation of nuclear-contaminated water environments and for underground dissolving extraction of the sandstone-hosted uranium ores.     

Fracture induced emission of alkali atoms from feldspar

Emission of neutral atoms (K and Na) and molecules (H₂O and KOH) observed during fracture of K-feldspar have been accounted for by two independent mechanisms. H₂O and KOH emissions are attributed to the venting of fluid-filled inclusions, while emission of atomic K is due to surface effects accompanying cleavage of crystalline feldspar. The intensity of emitted potassium, at least 6 × 10¹⁴ atoms/cm² of surface area, is sufficient to affect K activities in solution during microbrecciation in the presence of rock-dominated fluids.     

Sampling for Purgeable Organic Compounds Using Positive-Displacement Piston and Centrifugal Submersible Pumps: A Comparative Study

Positive-displacement piston pumps that minimize sample agitation have no apparent advantage over centrifugal submersible pumps when used to collect ground water samples for analysis of low concentrations of purge-able organic compounds. Analytical uncertainties inherent in laboratory environments appear to influence analytical results of low-concentration purgeable organic compound samples more than either pump type or sampling team. Centrifugal submersible pumps are at least equally efficient as positive-displacement piston pumps in the recovery of carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, and chloroform after sampling and analytical influences are made constant.     

Equatorial ionospheric response to isolated auroral substorms over a solar cycle (1980-85): evidence of longitudinal anomaly

The equatorial ionospheric response to 228 isolated, rapid-onset auroral substorms (as defined from the auroral electrojet index AE) was found from enhancements of the virtual (minimum) height of the F-region (h′F) in the declining phase of a solar cycle (1980-85). The responses, found for three longitudinal sectors at the equator: Africa (Ouagadougou and Dakar), Asia (Manila) and America (Huancayo), were compared with the response close to the auroral source region at Yakutsk (northern Siberia). The auroral substorm onsets were centered at 17 and 15 UT at sunspot maximum (1980-82) and minimum (1983-85), preceding by 3–5 h the period of post-sunset height rise in the African sector whereas other sectors were in the early afternoon (Huancayo) and morning (Manila). The African response, particularly at Ouagadougou, was distinctly different from other sectors. In the sunspot maximum years (1980-81) the auroral surges were followed after about 3 h by a sharp depression (h′F<0) in the post-sunset height rise, with a period of little or no response (h′F=0) in 1982. A response polarity reversal (h′F>0) was noted in this sector for sunspot minimum (1983-85) when large h′F enhancements were observed at the sunset region. The responses in the Asian and American sector were positive except for a case in Huancayo when response was negative, following an auroral surge before the sunset at this station. It appears that the aurorally generated large-scale travelling ionospheric disturbances (LSTIDs), which first cause positive height enhancements in a sub-auroral location (Yakutsk), subsequently affect the unstable post-sunset ionosphere in the equatorial Africa.     

国际古植物学1989年研究进展

古植物学是一个日新月异发展着的学科。每年,都有一些新的方法问世,它们结合地质学和生物学方法来研究地史时期植物的生活。其研究广度可以从1989年7月在美国首都华盛顿召开的第28届国际地质大会上明显看出。古植物学家们报告了他们关于“古气候”、“前寒武纪/寒武纪的过渡”、“泥炭和煤的来源”、“适应辐射”、“埋藏过程”、“特异埋藏”及南极地质等方面的研究成果;关于晚石炭世植物群的生物地理方面的文章也很多。 由Gastaldo(1989)编辑的《植物埋藏学——有机沉积过程》论文专辑是将更多的地质