Biological and ecological features of inland saline waters in North Hebei, China

During May and June 1991, the biological and ecological features of sixteen aquatic localities in Zhanjiakou region, Hebei, northern China, were investigated. Their salinity ranged from 0.98 to 175.2 g L⁻¹. Fish and benthic macroinvertebrates were depauperate. 116 samples were collected. 91 species (or genera) of phytoplankton and 94 species of zooplankton were recorded. In most of the saline lakes, Cl⁻ and Na⁺ were dominant, and alkalinity and pH values were higher. For phytoplankton, major species wereChroococcus minutus, Oscillatoria tenuis [blue-green algae];Chlamydomonas spp.,Chlorococcus spp.,Chlorella vulgaris, Crucigenia quadrata, Dunaliella salina, Kirchneriella contorta, Oocystis lacustris, Scenedesmus acuminatus [green algae]; andCyclotella meneghiniana, Navicula spp.,Nitzschia spp. [diatoms]. Other phytoplankton taxa present included:Cryptomonas erosa, Chroomonas acuta, Chromulina pascheri, Euglena viridis. For zooplankton, major species included:Vorticella campanula, Epistylis breviramosa, Euplotes terricola [protozoa];Brachionus plicatilis, Hexarthra fennica, Keratella quadrata, Notholca acuminata quadrata [Rotifera];Daphnia magna, D.longispina [‘Cladocera’];Artemia spp. [Anostraca];Arctodiaptomus rectispinosus andCyclops vicinus [Copepoda]. The species composition, distribution, salinity tolerance of planktonic forms in inland saline waters are discussed and their relationship with certain environmental factors.     

Characteristics of coastal phytoplankton near Cape Tastubec (northern Aral Sea), September 1993

The species composition, population density, biomass and main functional characteristics of the phytoplankton community near Cape Tastubec, northern Aral Sea in September 1993 were investigated. The characteristics investigated were daily primary production, decomposition, and photosynthetic intensity. The data indicate that certain changes in the structure and function of the phytoplankton have recently taken place.     

有限水域近水面气流演化特征试验研究

气流作为湖泊、湿地等有限水域的主要驱动力之一,其演化特征是研究水-气间能量与物质传递的基础,决定了水域水环境与水生态格局,具有重要研究意义.采用室内风洞水槽,通过设置不同试验风速,研究近水面气流与风速和吹程的响应关系与演化特征,并将光滑壁面条件下的气流特征作为试验对照组,分析时间域内风速垂向分布形式、摩阻风速、特征粗糙...     

确定深淡水湖泊的位温与密度

As a rule, the hydrodynamic modeling of processes in fresh waters is performed with the use of potential temperature θ and potential density ρ^*. However, the formulae of potential temperature for natural waters given by Phillips (1977), Gill (1982) and others take into account only adiabatic correction. They do not consider such important characteristics of natural waters as temperature of maximal density T_md (S,P) remoting of real temperatures T(S,P) in situ from T_md (T -T_md), changes of Tmd with decreasing of pressure P (depth Z), and the equation of water state. T_md=T_md(P) is the property of molecular structures of water (Horne, 1969). It is determined by the equation of water state:for example, for lacustrine waters in the form of Chen, Millero, (1986) ρ=ρ(S,T,P), where ρ,S are density and salinity natural water. There is given and discussed a new formula for the calculation of potential temperature. It is established that potential densities calculated according to the new formula suggested by us show the entire thermodynamic similarity of characteristics within T in situ. It is not observed while using the old formulae.     

冰藻对南大洋大西洋扇区南极磷虾越冬期间碳源的贡献

南极磷虾是南大洋生态系统的关键物种, 种群聚集在南大洋的大西洋扇区。海冰在南极磷虾生活史中起着重要作用, 海冰及其冰下环境为磷虾越冬提供了避难场所, 但海冰是否为磷虾越冬提供了重要的饵料存在一定的争议, 对此问题的解决需要量化源于海冰的冰藻对南极磷虾越冬期间饵料及碳源的贡献。基于2020年冬季(3~8月)于南大洋大西洋扇区48.1亚区(布兰斯菲尔德海峡周边区域)和48.3亚区(南乔治亚岛周边海域)采集的磷虾样品, 通过两种高支链类异戊二烯化合物(IPSO₂₅和HBI III)分别作为源于海冰的冰藻和源于水体浮游植物的生物标志物, 对两个区域冬季磷虾对冰藻和浮游植物的依赖进行研究。结果显示, 处于较高纬度、海冰密集度较高的48.1亚区的南极磷虾体内含有更高的IPSO₂₅, 而处于开阔水域48.3亚区的磷虾体内有更高比例的HBI III, 另外48.3亚区磷虾的δ¹³C和δ¹⁵N稳定同位素显著高于48.1亚区的磷虾。48.1亚区南极磷虾越冬期间对浮游植物和冰藻的依赖与体长相关, 其中体长相对较短的早期成体呈现更高的依赖性, 同时该区域磷虾对冰藻的摄食提高了其营养级地位。48.3区南极磷虾越冬期间两种类异戊二烯含量与δ¹⁵N稳定同位素数值呈负相关关系, 表明该区域南极磷虾在初级生产匮乏时会摄食动物性饵料。若未来南大洋大西洋扇区海冰持续减少, 这将对整个磷虾种群、磷虾渔业的可持续发展和区域生态系统的稳定性产生威胁。     

南疆近60年来风灾天气及灾度时空变化特征

利用新疆南疆各地州1949～2008年间发生的大风天气所造成的死亡人口、受灾农田面积、经济损失和死亡牲畜资料,评估南疆风灾的灾度及其时空变化特征进行深入分析。分析得出:(1)阿克苏、喀什和巴州重大风灾天气发生次数多,强度大,是风灾防范和灾后救助的重点地区;和田和克州重大风灾天气发生次数少,强度弱,是风灾防范和灾后救助的次重点地区;在4～5月份重大风灾天气发生次数多,持续时间长,而且4～5月份是作物播种和出苗期,大风容易成灾,为此4～5月份是风灾防范和灾后救助的重点季节。(2)重大风灾天气发生次数由20世纪50年代至90年代逐年增长,自21世纪开始略有减少;重大风灾天气在巴州发生次数最多,在60a间为84次,其次喀什75次,阿克苏67次,和田和克州较少。(3)风灾经济损失随着工农业生产总值的增长而增加,而且增长速度比经济增长速度快,建议增加防治风灾投入,改善生态环境,加快退耕还林还草进程,建立减灾系统,加强风灾防治。     

福建兴化湾表层沉积物中重矿物组分及其分布特征

对兴化湾17个站位表层沉积物中63～125μm粒级重矿物组分、含量、组合及分布特征进行了分析研究,并探讨了泥沙物质来源及重矿物与沉积环境的关系.结果表明,兴化湾重矿物平均含量(质量分数)为12.08%,高出其邻近的湄州湾(5.67%)6个百分点;重矿物共计37种,以磁铁矿、角闪石、绿帘石、钛铁矿、赤铁矿、褐铁矿、锆石为主.矿物种类揭示该海湾的泥沙主要来源于湾顶河流输入和周边陆域及湾内岛屿基岩风化侵蚀产物,而湾口以外海域的输入物质较少;依据主要重矿物含量和分布特征,将兴化湾划分为4个矿物组合区,各区重矿物组合类型不仅与物质来源有关,而且受水动力条件和沉积环境制约.     

福建省永定县樟坑-张岩下铜多金属矿化异常区的地质与矿化特征

闽西南坳陷带矿产资源丰富,是福建省铁、铜、金、煤、石灰岩等金属、非金属矿产的重要产地.永定樟坑-张岩下位于该带的西南部,通过对该区的地质、地球物理等方面的工作,对已发现的主要矿体进行系统的研究,发现了新的矿产地.文章论述了樟坑-张岩下铜多金属矿床的地质与地球物理特征,初步认为是复成因层控型矿床,是由于石炭系与早二叠系碳酸盐岩地层受到中、中酸性岩浆侵入而发生较大规模的夕卡岩化,成矿热液沿断裂面和层间滑脱构造面进一步对碳酸盐岩进行改造、交代而成.     

Structural Control to the Genesis of Sediment-hosted Disseminated Jinlongshan Gold Orebelt, China

Abstract. Jinlongshan gold orebelt is a newly discovered sediment-hosted gold orebelt in Southeastern Qinling Mountains hosted by Late Devonian to Early Carboniferous sedimentary rocks. The location of the belt is regionally controlled by E-W striking Zhenan-Banyan and Ningshan Faults, which were formed during the Indo-Sinian Orogeny. Circular patterns on TM images indicate that intrusive rocks occur at shallow depths in the Jinlongshan orebelt. Two basic types of disseminated and vein-type mineralization have been recognized. Calcareous siltstone is the most favorable host for disseminated mineralization. Vein-type mineralization is mostly hosted by limestone. Locally vein-type mineralization has envelop of disseminated mineralization.
Gold deposits are distributed north and south of the Zhenan-Banyan Fault zone, and the zone is considered to be the feeder zone and pathway for mineralizing fluids. During the Indo-Sinian Orogeny, magmatic and orogenic fluids may have extracted gold and other elements from underlying Proterozoic rocks and Paleozoic sedimentary rocks. The ore solutions evolved continuously with sedimentary rocks until gold was precipitated in appropriate structural sites. Exploration needs to be expanded along the Jinlongshan gold orebelt, focusing on inferred concealed intrusions and calcareous host rocks close to the Zhenan-Banyan Fault.     

福建湄州岛镁铁质岩墙群与寄主花岗岩的形成时差、地球化学及成因

福建湄洲岛的镁铁质岩墙群侵入于花岗岩中。镁铁质岩墙主要由斜长石(An=45~55,中-拉长石)、普通角闪石及少量辉石和石英等组成,锆石SHRIMP U-Pb年龄为(95±2)Ma。寄主花岗岩主要由石英、钾长石、斜长石(An=22~25,更长石)及少量的黑云母组成,锆石SHRIMP U-Pb年龄为(105±3)Ma。它们的形成时差约10 Ma。在岩石地球化学上,镁铁质岩墙群具有低CaO、MgO、TiO2而高Al2O3、轻稀土元素和大离子亲石元素富集、高场强元素亏损等特点,(87Sr/86Sr)i=0.705 2~0.705 4,εNd(t)=-0.03~1.57,与福建沿海同时代镁铁质岩墙群相似。寄主花岗岩与沿海高钾钙碱性花岗岩基本相同,都具有高硅、富碱的特点,它们的w(SiO2)>75%,A/CNK=1.05~1.12,w(K2O+Na2O)=7.68%~8.12%,w(K2O)>w(Na2O),(87Sr/86Sr)i=0.705 5,εNd(t)=-3.92。综合研究表明:湄洲岛寄主花岗岩是由受消减作用影响的岩石圈地幔部分熔融而产生的玄武岩浆底侵,并熔融中下地壳所产生的花岗岩浆形成;而镁铁质岩墙是底侵、滞留并经过结晶分异的玄武质岩浆,因地壳再次伸展,而沿花岗岩体中节理侵入形成。湄洲岛花岗岩与镁铁质岩墙群形成于伸展构造环境,对应福建沿海2次地壳伸展事件。湄洲岛花岗岩和镁铁质岩墙群的研究为沿海晚中生代构造-岩浆活动提供了一个新例证,同时为福建沿海晚中生代岩石圈伸展时限提供了制约。