Regional ground-water mixing and the origin of saline fluids: midcontinent, United States

Ground waters in three adjacent regional flow systems in the midcontinent exhibit extreme chemical and isotopic variations that delineate large-scale fluid flow and mixing processes and two distinct mechanisms for the generation of saline fluids. Systematic spatial variations of major ion concentrations, H, O, and Sr isotopic compositions, and ground-water migration pathways indicate that each flow system contains water of markedly different origin. Mixing of the three separate ground waters exerts a fundamental control on ground-water composition. The three ground waters are: (i) dilute meteoric water recharged in southern Missouri; (ii) saline Na-Ca-Cl water in southeastern Kansas of far-traveled meteoric origin that acquired its salinity by halite dissolution; and (iii) Na-Ca-Cl brines in north-central Oklahoma that may have originated as Paleozoic seawater.     

Mars: an evolving atmosphere

Photochemical reactions in the martian exosphere produce fast atoms of oxygen, carbon, and nitrogen and provide large escape fluxes of these elements. They appear to play a crucial role in the evolution of the martian atmosphere. The relative outgassing rates of H(2)O and CO(2) on Mars are comparable with terrestrial values, although absolute rates for Mars are lower by a factor of 10(3). Nitrogen is a trace constituent, less than 1 percent, of the present martian atmosphere.     

Recent planktonic foraminifera: dominance and diversity in north atlantic surface sediments

Foraminferal dominance values above 50 percent and associated diversity minimums in surface sediments of the North Atlantic coincide with past extremes of temperature, productivity, or salinity in overlying surface waters. These parameters delimit a cold PolarSubpolar water mass and an impoverished, saline Southern Sargasso Central water mass for the late Recent. Anticipated pole-to-equator diversity and dominance gradients in the open ocean are virtually eliminated by the stronger trends of the vigorous subtropical North Atlantic gyre.     

Water on Mars: Clues from Deuterium/Hydrogen and Water Contents of Hydrous Phases in SNC Meteorites

Ion microprobe studies of hydrous amphibole, biotite, and apatite in shergottite-nakhlite-chassignite (SNC) meteorites, probable igneous rocks from Mars, indicate high deuterium/hydrogen (D/H) ratios relative to terrestrial values. The amphiboles contain roughly one-tentn as much water as expected, suggesting that SNC magmas were less hydrous than previously proposed. The high but variable D/H values of these minerals are best explained by postcrystallization D enrichment of initially D-poor phases by martian crustal fluids with near atmospheric D/H (about five times the terrestrial value). These igneous phases do not directly reflect the D/H ratios of martian "magmatic" water but provide evidence for a D-enriched martian crustal water reservoir.     

中国北方内陆盐水水域鱼类的种类和多样性

根据中国北方内陆盐水水域生物资源的调研材料，结合国内已有的报道，试对中国北方内陆盐水水域鱼类种类和分布做初步分析，在已掌握的60多个水域资料中，有鱼生存的21个盐水湖，盐度为1．24－13．00，碱度为3．0－44．5mmol/L,pH8.20-9.45，共见到鱼类74种，隶属8目16科，其中许多是北方区，宁蒙区和华西区鱼类的指示种，也有华东区和华南区的代表种，各湖的鱼类种数在1－27种之间，北方区和宁蒙区各水域鱼类区系的相似系数较高，新疆盐水湖针类种类组成较有特点，作者还讨论了盐度、碱度，pH等生态因子对鱼类的种类和多样性的影响，以及对盐水水域鱼类资源和多样性的保护利用方式。     

Stochastic late accretion to Earth, the Moon, and Mars

Core formation should have stripped the terrestrial, lunar, and martian mantles of highly siderophile elements (HSEs). Instead, each world has disparate, yet elevated HSE abundances. Late accretion may offer a solution, provided that ≥0.5% Earth masses of broadly chondritic planetesimals reach Earth's mantle and that ~10 and ~1200 times less mass goes to Mars and the Moon, respectively. We show that leftover planetesimal populations dominated by massive projectiles can explain these additions, with our inferred size distribution matching those derived from the inner asteroid belt, ancient martian impact basins, and planetary accretion models. The largest late terrestrial impactors, at 2500 to 3000 kilometers in diameter, potentially modified Earth's obliquity by ~10°, whereas those for the Moon, at ~250 to 300 kilometers, may have delivered water to its mantle.     

苏打盐渍土理化性质的微域特征及其对水盐运移的影响

    通过野外定位观测和室内分析,探讨微域尺度(32 m长的横截面)苏打盐渍土壤的性质以及水盐运移规律.结果表明:盐渍土地区在微域尺度上呈现盐化草甸土-浅位柱状碱土-白盖苏打碱土-中位柱状碱土的格局.苏打碱土分布在微坡地和高平地,其质地剖面结构为粉砂质亚黏土-黏土-粉砂-砂砾;盐化草甸土分布在相对低洼的部位,其质地以粉砂和砂砾结构为主.土壤理化性质的差异和微地貌特征影响盐渍土壤的水分-地下水之间的迁移转化.浅埋地下水的波动与大气降水在盐化草甸土水分的迁移转化密切相关,洼地(盐化草甸土)成为地表径流迁移汇集区.冻融积盐是松嫩平原土壤积盐的重要原因.冻融季节,盐化草甸土成为潜水迁移的汇集区.大量的潜水迁移并贮存在盐化草甸土冻层(10～30 cm土层的含水率高达50%以上),这可能是冬季地下水位急剧下降的一个重要原因.受冻结作用的影响,盐分自下而上在苏打碱土的冻层积聚,在消融期盐分迅速表聚使土壤表层的盐渍化程度加重.     

基于Landsat影像的崇明岛东滩土壤盐分遥感反演技术

目前我国土地资源面临着严重的盐碱退化问题。以上海市崇明岛东滩盐碱土为研究对象,基于野外实地调查土壤盐分数据以及Landsat遥感影像数据计算获取的各波段反射率、盐分指数（salinity index, SI)、盐分指数1（salinity index 1, SI1）、归一化差分植被指数（normalized difference vegetation index, NDVI）、冠层盐分响应指数（canopy response salinity index, CRSI）和陆地表面水分指数（land surface water index, LSWI）,采用多元样条自回归模型（multivariate adaptive regression splines, MARS）与偏最小二乘回归方法（partial least squares regression, PLSR）分别建立土壤盐分的回归模型,并对区域盐碱土的空间格局进行探究。结果表明:①滨海土壤盐分在近红外波段有明显的吸收作用,与近红外波段、短波红外波段和NDVI相关系数较高;②MARS模型较PLSR模型对于样点土壤盐分反演有更好的效果（R2分别为0.74和0.70）;③崇明东滩滨海土壤盐分在空间上具有较高的异质性,水体附近和滩涂土壤盐分较高,林地和农田土壤盐分较低。该结果为滨海地区区域尺度上的土壤盐碱化监测提供范例,为滨海土壤盐渍化的治理及岛屿的生态建设提供参考依据。     

黄海北部仿刺参养殖池塘关键环境因子的周年变化与管理研究

研究了黄海北部非投喂型仿刺参Apostichopus japonicus养殖池塘的温度、溶氧、盐度、pH和大型生物等环境因子的周年变化特点,以及春季化冰期池塘的温度、盐度、pH的日变化规律,同时对池塘的纳潮换水、水位管理以及敌害生物的控制等技术环节进行了探讨,分析了环境因子与仿刺参养殖的关系。结果表明：（1）池塘周年水温变化在-1．2～30．4℃,最高在8月,最低在1月;溶解氧值波动于3．5—21．3mg／L,冬季高,夏季低;溶解氧与温度之间的回归关系为Do=0．018T^2-0．818T＋15．805;pH值波动于7．印～8．72,冬、夏季高,春、秋季低;盐度波动于22．5～33．5,夏季偏低。（2）冬季水温下降到-1．0℃时,池塘表层开始结冰并逐渐封冰;春季在化冰时存在温度和盐度跃层,可采用将表层水排放掉的方法消除跃层。（3）池塘的大型植物主要包括缘管浒苔、刚毛藻、沟草等,大型动物主要有矛尾缎虎鱼、石鲽、花鲈、蓝点马鲛、鲮、斑鲦、鳐等鱼类,太平洋牡蛎、菲律宾蛤仔、黑荞麦蛤等贝类以及脊尾白虾、口虾蛄等。（4）在化冰期注意池塘盐度变化,化冰前池塘冰下水位应控制在120～130cm以上,化冰后池塘水深应控制在150—170cm以上。（5）在夏季高温期应注意监测溶解氧的变化,防止因藻类死亡腐败、溶解氧含量下降而导致仿刺参发生缺氧死亡的现象。     

Evidence that the reactivity of the martian soil is due to superoxide ions

The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.     

不同矿化度咸水灌溉对小麦和玉米产量及土壤盐分运移的影响

2006~2008年在河北省农林科学院旱作节水试验站,研究了黑龙港地区利用不同矿化度咸水灌溉的小麦和玉米产量以及土壤盐分运移累积的影响。结果表明：作物产量随着灌溉水矿化度的升高而逐渐降低,4 g/L咸水灌溉的小麦和玉米产量分别较淡水灌溉减产8.87%和7.16%;在0~40 cm作物主要根层,矿化度〉4 g/L的咸水灌溉土壤盐分增加幅度较大,增加值为2.13~2.56 g/kg,而〈4 g/L的咸水灌溉土壤盐分一直都〈2 g/kg。在黑龙港地区利用微咸水直接灌溉时,咸水矿化度一般不宜超过4 g/L。     

三北地区内陆盐水生物资源及其渔业利用

报道了1981－2001年对中国三北地区内陆盐水生物资源调研的结果，总计对大约50个水体进行了采样调查，其中盐度为0．8－286．0，碱度1．75－67．00mmol/L，pH7.3-10.6，离子系数0．45－67．00，共见到浮游植物132种和变种，浮游动物193种，底栖动物31种，鱼类37种，根据出现率和平均生物量，有33种浮游植物，34种浮游动物和6种底栖动物为三北地区内陆盐水的主要种类，此外，还讨论了浮游生物对盐度，碱度和pH的适应性，内陆盐水生物资源的渔业利用以及利用盐水或耐盐性淡水枝角类作为海水鱼苗活饵料的前景。     

三北地区内陆盐水的轮虫

1990～1991年间在三北地区盐度0.5～214 g/L的28个内陆水体采集了浮游轮虫水样。共检出59种轮虫。根据出现率和平均密度,下列13种是所调查盐水轮虫区系的主要种类:褶皱臂尾轮虫、角突臂尾轮虫、壶状臂尾轮虫、变异臂尾轮虫、盖氏晶囊轮虫、矩形龟甲轮虫、螺形甲龟轮虫、爱德里亚狭甲轮虫、方尖削叶轮虫、一种单趾轮虫、针簇多肢轮虫、长三肢轮虫和环顶巨腕轮虫。文中讨论了内陆盐水轮虫的种类组成、分布和盐度耐性,以及盐度、碱度、pH、离子系数与种类多样性之间的关系等问题。     

秸秆覆盖对盐渍土水分状况的影响

在３种质地（砂壤、轻壤、中壤）、３种盐化程度（中度盐化、重度盐化、盐土）的土壤上进行了秸秆覆盖条件下的水分运动的模拟试验,结果表明秸秆覆盖可明显降低土壤水分蒸发,与不覆盖相比,覆盖１．５ｔ／ｈｍ２土壤水分蒸发减少量,砂壤中度盐化土为２６．８７％,砂壤重度盐化上为３９．２４％,轻壤重度盐化土为３９．３１％,轻壤盐土为４０．２０％,中壤重度盐化土为４０．２４％,中壤盐上为５５．５６％。覆盖６．７５ｔ／ｈｍ２土壤水分蒸发减少量,砂壤中度盐化土为６９．０９％,砂壤重度盐化土为７１．１８％,轻壤重度盐化土为７５．９４％,轻壤盐土为７３．８６％,中壤重度盐化土为７４．２５％,中壤盐土为８８．１３％,并且覆盖量在１．５～６．７５ｔ／ｈｍ２的范围内,土壤水分蒸发量随着覆盖量的增加而逐渐减少。     

Martian atmospheric erosion rates

Mars was once wet but is now dry, and the fate of its ancient carbon dioxide atmosphere is one of the biggest puzzles in martian planetology. We have measured the current loss rate due to the solar wind interaction for different species: Q(O+) = 1.6.10(23) per second = 4 grams per second (g s(-1)), Q(O+2) = 1.5.10(23) s(-1) = 8 g s(-1), and Q(CO+2) = 8.10(22) s(-1) = 6 g s(-1) in the energy range of 30 to 30,000 electron volts per charge. These rates can be propagated backward over a period of 3.5 billion years, resulting in the total removal of 0.2 to 4 millibar of carbon dioxide and a few centimeters of water. The escape rate is low, and thus one has to continue searching for water reservoirs and carbon dioxide stores on or beneath the planetary surface and investigate other escape channels.     

新型复合功能菌群的构建及其在近海养殖水体BOD微生物传感器中的应用

生化需氧量(BOD)是监测水体中可生物降解的有机物含量的一个重要参数,是目前最常用的水体有机污染综合评价指标之一。随着环境污染问题日益严重,建立和发展快速测定生化需氧量的体系尤其重要。适用于淡水的BOD测定仪已经成型,海水盐度高,BOD浓度低,测定仪样品传输及测量的精度和微生物传感器菌种的耐盐性给构建海水BOD自动测定体系带来困难。从三亚近海养殖水体污染严重的三亚海宝近海养殖专业合作社养殖场水样中分离得到3株能高效降解蛋白质、淀粉和油脂的菌株Bacillus HXY-10、As-pergillus sp.HXY-3和Methylobacterium sp.HXY-7,通过共培养构建能高效去除养殖水体中氨氮和亚硝酸盐氮的固定化复合功能菌群,采用夹膜法制作BOD生物传感器微生物膜。传感器响应电流与水样的BOD含量在2～60 mg/L之间呈线性关系,相关系数为0.992 3。对含有已知BOD含量的水样8次测量,RSD为3.34%,表明BOD传感器检测体系重现性良好,为该复合功能菌群进一步应用于近海养殖水体BOD传感器奠定基础。     

Evidence for recent groundwater seepage and surface runoff on Mars

Relatively young landforms on Mars, seen in high-resolution images acquired by the Mars Global Surveyor Mars Orbiter Camera since March 1999, suggest the presence of sources of liquid water at shallow depths beneath the martian surface. Found at middle and high martian latitudes (particularly in the southern hemisphere), gullies within the walls of a very small number of impact craters, south polar pits, and two of the larger martian valleys display geomorphic features that can be explained by processes associated with groundwater seepage and surface runoff. The relative youth of the landforms is indicated by the superposition of the gullies on otherwise geologically young surfaces and by the absence of superimposed landforms or cross-cutting features, including impact craters, small polygons, and eolian dunes. The limited size and geographic distribution of the features argue for constrained source reservoirs.     

A wetter, younger Mars emerging

Most researchers have believed that the days were long gone when water splashed on the surface of Mars or even near it. Now continuing analyses of martian meteorites and stunning images from the Mars Global Surveyor (MGS), which has been in orbit since 1997, are breathing new life into the Red Planet. Last month's announcement that the camera aboard MGS had spied signs of geologically recent--possibly even ongoing--water seeps has caught everyone's attention. Other, perhaps more persuasive, signs also suggest that water may even now flow on or beneath the frigid surface.     

咸水滴灌条件下棉花生长和氮素吸收对水氮的响应

[目的]研究咸水滴灌条件下棉花生长和氮素吸收对水氮的响应.[方法]试验设置了3种灌溉水盐度0.35(S1)、4.61(S2)和8.04(S3)dS/m,2个灌水量405(L1)和540(L2)mm以及2个施氮量240(N1)和360(N2) kg/hm2.[结果]棉花的株高在生长前期主要受灌溉水盐度、灌水量及二者的交互作用和盐度、灌水量和施氮量三者的交互作用影响显著,生长后期主要受灌水量的影响显著.高灌水量L2(540 mm)各处理株高为S2＞S1＞S3,施氮量对株高的生长差异影响不显著.棉花茎和叶的干物质积累量受灌溉水盐度、灌水量和施氮量其中二者的交互作用影响显著,而棉铃和总的干物质积累量受交互作用不显著.[结论]棉花的氮素吸收量受灌溉水盐度、灌水量和施氮量三因素及其两者或三者的影响显著;随着灌溉水盐度的增加,棉花的氮素吸收量呈下降的趋势;而氮素吸收量随着灌水量的增大显著增加,表明增加灌水量可促进氮素吸收.