The influence of increased iron concentration on survival and growth of seedlings and young plants of eelgrass Zostera marina

Iron (Fe) is an essential nutrient for plants but toxic at high concentrations. We subjected seedlings and young plants of eelgrass Zostera marina to different seawater iron concentrations (500, 600, 700, 800, 1,000 and 1,500 μg/L) for 30 days under controlled laboratory conditions. Natural seawater without added iron (500 μg/L) was used as reference seawater. No sediments were provided to avoid iron scavenging by particle surfaces in the sediment. We measured plant response in terms of survivorship, morphology, growth rate and productivity. Survival analysis combined with morphological, dynamic and productive assessment suggested that the optimum seawater iron concentration for the establishment of Z. marina seedlings and young plants is 700 μg/L. The no observed effect concentration, lowest observed effect concentration, lethal concentration that caused an increase in mortality to 10% of that of the control, and the effect concentration that caused a decrease in growth to 10% of that of the control values of young plants were significantly lower than those of seedlings, implying an increased sensitivity to high Fe concentrations (>1,000 μg/L). This study further develops our understanding of the physiological ecology of the early life stages of Z. marina and provides data that could prove helpful in the development of successful eelgrass restoration and conservation.     

不同氮、磷浓度及配比对铜藻(Sargassum horneri)幼苗生长的影响

采用铜藻(Sargassum horneri)幼苗为实验对象,分别以Na NO3和Na H2PO4为氮源和磷源,研究了不同氮磷质量浓度及氮磷配比对铜藻幼苗生长的影响。进行了氮、磷单因子实验、双因子实验以及不同氮磷配比实验,实验时间为8d。结果表明:氮和磷对铜藻幼苗生长影响极显著(P0.01),且当氮、磷的质量浓度分别为8mg/L、0.4mg/L时,铜藻幼苗的特定生长率最大;交互作用影响不显著(P0.05),不同质量浓度的氮为主效应;不同氮磷质量浓度比影响极显著(P0.01),且当氮磷比为10:1时,铜藻幼苗的特定生长率最大。研究结果为铜藻幼苗培育过程中营养盐的合理调控提供了理论依据。     

多波束测深海底混响仿真研究

海底混响是海洋混响的重要组成部分,采用模拟仿真进行验证分析,是仿真技术的一项重要应用。采用单元散射模型,研究在单发射阵元下,分布在同一直线上多个接收阵元接收的海底回波,忽略声波传播的相位起伏,只考虑振幅起伏,将传播损失、声吸收系数、海底反射损失、海底沉积层密度等参数带入海底混响仿真数学模型,仿真海底混响,使其更加接近海底的实际情况。     

基于FTIR和MODIS数据估算新疆沙漠宽波段地表比辐射率

基于FTIR和MODIS数据,建立了新疆沙漠宽波段（8～13.5 μm）地表比辐射率的最优估算模型。首先,利用傅立叶变换热红外光谱仪观测的塔克拉玛干沙漠地表比辐射率光谱数据,结合同期MODIS温度/比辐射率产品MOD11A1的29、31和32波段比辐射率值和MOD09A1的第7波段反射率值,建立宽波段地表比辐射率估算模型,并分别采用观测数据和光谱库数据验证了模型的精度,估算结果的均方根误差分别为0.0041和0.0081。其次,选择最优估算模型,利用MODIS数据,估算了新疆4个沙漠的宽波段地表比辐射率,得到了沙漠地表比辐射率的空间分布特征。结果表明：塔克拉玛干沙漠和库鲁克库姆沙漠气候干燥稳定,地表比辐射率分布较为均匀,范围为0.850～0.915;古尔班通古特沙漠受到植被和地表水分的影响,比辐射率空间分布不均匀,范围为0.890～0.915;库木塔格沙漠的地表比辐射率分布与其羽状地表类似,范围为0.860～0.910。     

Experimental study on the vertical deformation of aquifer soils under conditions of withdrawing and recharging of groundwater in Tongchuan region,China

Land subsidence due to aquifer-system compaction accompanying groundwater extraction is a global hazard. Rising urban construction and groundwater demand necessitate increased awareness and better understanding of the geological problem. Motivated by the lack of laboratory-scale studies on this issue, an experimental investigation on the newly developed Tongchuan region, China, is presented. The study addresses the deformation behaviors of three soil samples, with the lithology of silty clay, silt, and fine sand, under the conditions of groundwater withdrawal and recharge using the GDS Consolidation Testing System. Results indicate that all three samples were characterized by elastic–plastic deformation under the conditions of withdrawing and recharging. The vertical deformation of the silty clay in the aquitard above the first confined aquifer was larger than those of the other two samples, and its deformation is a gradual and long process; thus, considerable attention should be paid to deformation in this aquitard due to the apparent creep effect and tiny rebound deformation. However, the settlement of the fine sand in the second confined aquifer cannot be ignored due to the great thickness of the aquifer. For the same soil, as the pore-water pressure declined, the unit rate of vertical deformation decreased gradually, whereas the creep effect of deformation in the later declining stage of pore-water pressure was more apparent than that in the former declining stage. These observations are highly important to the local government, which is developing measures to prevent and control subsidence.     

Is there the Paleoproterozoic komatiite related to mantle plume in the Jifeng area,Northern Great Xing’an Range,NE China?

International Journal of Earth Sciences -     

Discovery of the early Jurassic Gajia mélange in the Bangong–Nujiang suture zone: Southward subduction of the Bangong–Nujiang Ocean?

International Journal of Earth Sciences - Mélange records a series of geological processes associated with oceanic subduction and continental collision. This paper reports for the first time...     

DFT study of the carbonation on mineral aerosol surface models of olivine: effect of water

Mineral aerosols play a significant role in gas–solid interfacial and atmospheric chemistry. Carbonation of olivine aerosol, which takes place in a multiphase reaction processes, can be an effective means to reduce the concentration of atmospheric carbon dioxide. Due to the presence of a huge reserve of silicate minerals in nature, olivine aerosol could be an ideal potential raw material for mineral carbonation for its higher reactivity with H₂O and CO₂. However, quantitative information about the carbonation process on the surface of natural olivine aerosol is not available. In this paper, calculations on the carbonation reaction processes with and without a H₂O molecule using a periodic olivine model has been carried out via the density functional theory. The pathways and their corresponding energies and structures in the carbonation reactions have been established, and the effect of water as means to reduce the energy barriers and stabilize the carbonated structures by forming hydrogen bonds has been confirmed.     

Analysis on variation characteristics of geothermal response in Liaoning Province

Due to energy shortage and increasing environmental awareness, resources in shallow underground space have been rapidly exploited and utilized. So that studying variation characteristics of geothermal response in gneiss is necessary for effective and rational use of underground heat. Based on field test of thermal response in gneiss under hydrogeological survey project carried out in shallow geothermal energy development zone in Liaoning Province, this thesis analyzes mathematical statistics of geothermal response characteristics in main gneiss of Laoning Province. The initial formation temperature ranges from 10.80℃ to 15.80℃ according to field test. The statistical results show that in the condition of natural water content, the average thermal conductivity of Quaternary loose rocks comes as clay silty silty fine sand medium sand coarse sand gravelly sand. This order is consistent with thermal conductivity characteristics of gneiss obtained in the laboratory. Formation temperature recovery in different strata follows as granite medium sand clay. This order is opposite to the absolute value of temperature recovery curve slope of corresponding lithology, which shows that the stratum with higher temperature recovery rate has lower temperature recovery curve slope.     

扬州捺山上新世盾形火山机构地质特征与地质公园建立

扬州仪征捺山上新世盾形火山机构是一套"爆发相—溢流相—次火山相"喷发旋回,伴有多个寄生火山口,其完整程度为江苏唯一,国内罕见。文章系统介绍捺山上新世盾形火山机构,详细论述该火山机构的地质特征及成因。这是对该地质遗迹进行的首创性工作,对进一步的地质科研、科普教育及生态旅游具有重要意义。