山东半岛南北两侧海域真核浮游生物群落特征及与环境因子的相关性分析   总被引：1，自引：0，他引：1  

刘朋超  王卫军  骆启豪  李彬  孙国华  赵强  张金浩  杨建敏 《海洋与湖沼》2019,50(4):876-885

为了解山东半岛南北两侧的烟台崆峒岛(KTD)海域和日照东港(DG)海域真核浮游生物群落特征,采用高通量测序技术,以18S rDNA V4区为目标基因,对2017年10月至2018年7月两海域的真核浮游生物多样性进行了检测;同期测定两海域的环境因子(溶解氧、氨氮含量等10个理化指标),并与真核浮游生物丰富度做相关性分析。实验结果表明:通过高通量测序技术共鉴定出浮游生物455种,其中,KTD海域共检测出真核浮游生物36个门类424种;DG海域共检测出真核浮游生物34个门类365种。绿藻门(Chlorophyta)、硅藻门(Diatomea)是两海域浮游植物中整体丰度最高的门类。KTD海域,绿藻门各月丰度在3.0%—21.3%之间,其中2018年7月(K1807)最高,达到了21.3%;硅藻门各月丰度在2.0%—16.59%之间,其中2018年2月(K1802)最高,达到了16.59%。DG海域,绿藻门各月丰度在2.0%—12.3%之间,其中2017年11月份(D1711)最高,达到了12.3%;硅藻门各月丰度在2.0%—47.0%之间,其中1月(D1801)最高,达到了47.0%。占优势地位的浮游动物主要是节肢动物门类的物种,其每月丰度分别在6.0%—38.9%和7.6%—48.6%之间。环境因子相关性分析表明水温、DO、pH、硅酸盐、硝酸盐氮等环境因子为影响该海域浮游生物群落结构的主要因子。研究结果对了解双壳经济贝类养殖区饵料组成及其在时空的变化,对海岸带食物网、生态基础管理和海洋经济贝类养殖生产等方面提供数据支撑。  相似文献   

Local meteoric water lines describe extratropical precipitation     

Devin F. Smith  Elsa Saelens  Deborah L. Leslie  Anne E. Carey 《水文研究》2021,35(2):e14059

Stable water isotopes δ¹⁸O and δ²H are used to investigate precipitation trends and storm dynamics to advance knowledge of precipitation patterns in a warming world. Herein, δ¹⁸O and δ²H were used to determine the relationship between extratropical cyclonic precipitation and local meteoric water lines (LMWLs) in the eastern Ohio Valley and the eastern United States. Precipitation volume weighted and unweighted central Ohio LMWLs, created with samples collected during 2012–2018, showed that temperature had the greatest effect on precipitation isotopic composition. HYSPLIT back trajectory modelling showed that precipitation was primarily derived from a mid-continental moisture source. Remnants of major hurricanes were collected as extratropical precipitation during the 2012–2018 sampling period in central Ohio. Extratropical precipitation samples were not significantly different from the samples that created the central Ohio LMWL. Six additional LMWLs were derived from United States Geological Survey (USGS) Atmospheric Integrated Research Monitoring Network (AIRMoN) samples collected in Pennsylvania, Delaware, Tennessee, Vermont, New Hampshire, and Oxford, Ohio. Meteoric water lines describing published samples from Superstorm Sandy, plotted with these AIRMoN LMWLs, showed isotopic composition of Superstorm Sandy precipitation was commonly more depleted than the average isotopic composition at the mid-latitude locations. Meteoric water lines describing the Superstorm Sandy precipitation were not significantly different in slope from LMWLs generated within 300 km of the USGS AIRMoN site. This finding, which was observed across the eastern Ohio Valley and eastern United States, demonstrated a consistent precipitation δ²H–δ¹⁸O relationship for extratropical cyclonic and non-cyclonic events. This work also facilitates the analysis of storm development based on the relationship between extratropical event signature and the LMWL. Analysis of extratropical precipitation in relation to LMWLs along storm tracks allows for stronger development of precipitation models and understanding of which climatic and atmospheric factors determine the isotopic composition of precipitation.  相似文献   

The role of fog,orography, and seasonality on precipitation in a semiarid,tropical island          下载免费PDF全文

Sarah R. Schmitt  Diego A. Riveros‐Iregui  Jia Hu 《水文研究》2018,32(18):2792-2805

Isotopes of water (²H/¹H and ¹⁸O/¹⁶O) are commonly used to trace hydrological processes such as moisture recycling, evaporation loss, and moisture source region and often vary temporally in a given region. This study provides a first‐ever characterization of temporally variable precipitation mechanisms of San Cristóbal Island, Galápagos. We collected fog, rain, and throughfall samples over three field seasons to understand the mechanisms driving seasonal‐ and event‐based variability in the isotopic composition of precipitation in Galápagos. We establish that fog is a common phenomenon in San Cristóbal, especially during the dry season, and we found that fog, compared with cocollected rainfall, is consistently enriched. We further suggest that the relative contribution of fog formed via different mechanisms (orographic, advective, radiation) varied seasonally. We found that the source region is the most dominant control of the isotopic composition of rainfall in the Galápagos at both the seasonal and event scales, but subcloud evaporative processes (the nontraditional manifestation of the amount effect) became a dominant control on the isotopic composition of rainfall during the dry season. Overall, our findings suggest that understanding seasonally variable water‐generating mechanisms is required for effective water resource management in San Cristóbal Island and other semiarid island ecosystems under current and future regimes of climate change.  相似文献   

Streamwater ages in nested,seasonally cold Canadian watersheds     

Samuel Bansah  Genevieve Ali 《水文研究》2019,33(4):495-511

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Snowpack disrupts relationship between young water fraction and isotope amplitude ratio; approximately one fifth of mountain streamflow less than one year old     

Éowyn M. S. Campbell  Igor Pavlovskii  M. Cathryn Ryan 《水文研究》2020,34(25):4762-4775

Previous “fraction of young water” (F_yw) estimates based on relative annual isotopic amplitudes in precipitation (A_p) and streamflow (A_s) produced low F_yw values in mountain catchments, which is contrary to extensive research that reports rapid water transmission in mountains. This study investigated this discrepancy by testing the effect of snow accumulation on the model that underpins the F_yw method. A Monte-Carlo analysis of simulations for 20,000 randomly-generated catchment model configurations used 10 years of precipitation inputs for the Upper Elbow River catchment in the Rocky Mountains (Alberta, Canada) to model discharge with and without snowpack storage of winter precipitation. Neither direct nor modified precipitation input produced a 1:1 relationship between A_s/A_p and F_yw, undermining the applicability of the original F_yw method in mountain watersheds with large seasonal snow accumulation. With snowpack-modified input a given A_s/A_p ratio corresponds to a range of F_yw values, which can still provide semi-quantitative information. In the small (435 km²) Elbow River catchment a F_yw range of 7–23% supports previous findings of rapid transmission in mountain catchments. Further analysis showed that the improved discharge prediction (Nash–Sutcliffe efficiency > 0.9) correlates with higher F_yw values and demonstrated that the interannual shifts in δ¹⁸O can be used to estimate of new water (<1 year) fraction in winter streamflow, and the estimate of 20% for the Elbow River further supports rapid transmission in mountain catchments.  相似文献   

DFT对Rb⁺水合团簇及其相关性质的分析          下载免费PDF全文

张文倩  葛蒲  房春晖  周永全  朱发岩  刘红艳  李武 《盐湖研究》2019,27(3):81-92

运用密度泛函理论(DFT)在ωB97XD/gen (O、H元素Aug-cc-PVDZ; Rb元素Lanl2DZ)基组水平上研究了[Rb(H_2O)_n]~+(n=1～12)水合团簇的结构和光谱学性质。研究结果表明,通过分析气相和液相中的稳定能以及水合团簇可知,稳定构型出现在8配位的团簇中。第一配位层水分子数为8时形成Rb~+第一近似饱和水合层。此外,拉曼光谱显示[Rb(H_2O)_n]~+(n=1～12)水合团簇中O-H伸缩振动峰随着水分子数增加发生移动和加宽,Rb~+发生水合时,O-H对称和非对称伸缩振动发生红移,随着水合数的增多,频率蓝移。此外,文中对拉曼光谱中O-H振动的频率位置结合团簇结构进行了说明。  相似文献   

利用徕卡GS18仪器进行高精度RTK定位试验与分析     

伍吉仓  李玉婷 《测绘通报》2019,(4):155-158

目前，GNSS和IMU（惯性测量单元）传感器融合领域的快速发展，给高精度RTK定位带来了新的机遇。传统倾斜补偿的解决方案大多是使用磁力计和INS（惯性导航系统），对电磁干扰十分敏感并且需要现场校准，倾斜补偿的角度范围通常限制在15°；以内。为了克服上述的缺点，徕卡GS18 GPS倾斜机使用基于工业级别微电子机械传感器MEMS的IMU来补偿测杆倾斜情况的位置改正。本文通过试验检验了徕卡GS18仪器在大角度倾斜和不同复杂环境下的定位精度，结果表明GS18倾斜机能较好实现倾斜补偿，在有信号遮挡等场景下仍能获得厘米级定位精度。  相似文献   

青藏高原西部阿汝冰芯记录的近100 a气温变化研究   总被引：2，自引：2，他引：0  

杨丹丹  姚檀栋  邬光剑  朱美林  德吉 《冰川冻土》2021,43(1):124-134

以2017年9月钻取自青藏高原西部阿汝冰崩区长度55.29 m的阿汝冰芯为研究对象,通过冰芯δ¹⁸O记录与Nye模型重建了冰芯上部17.87 m的时间序列是1917—2016年。结合冰芯邻近的改则、狮泉河气象站1973—2016年夏季平均气温数据,通过相关性分析及线性回归法、Mann-Kendall（M-K）检验分析,发现冰芯与气象站记录的过去44年气温显著升高;根据M-K突变检验得出,20世纪80年代是气温变化由高—低—高的转折时期,且阿汝冰芯记录的突变年份1981年前后气温上升约1.97 ℃。同样地,采用线性回归法、M-K检验分析阿汝冰芯与邻近的古里雅冰芯共同记录的1917—1991年气温变化情况,发现两支冰芯记录的75年间气温变化总体呈上升趋势;根据M-K突变检验得出,升温始于20世纪30年代中后期并于50年代达到显著升温的趋势,且阿汝冰芯记录的突变年份1949年前后气温上升了约1.1 ℃。阿汝冰芯与气象站和古里雅冰芯记录的气温变化具有一致的升温趋势,但阿汝冰芯记录的增温幅度比气象站记录高,同时比古里雅冰芯记录的增温幅度小。  相似文献   

运用H、O同位素分析石阡地区地热水来源     

李永康  陈正山  王甘露 《水文》2021,41(1):28-34

通过对贵州省石阡地区地热水、冷泉及河流的地热地质条件、水化学成分及氢氧同位素分析,对该地区的地热水、冷泉及河流的水化学特征、来源及石阡地区的补给模式进行了研究。温泉水属于低中矿化度的弱碱性水;温泉群中阳离子以Ca^2+、Mg^2+为主,阴离子以SO4^2-和HCO3^-为主,研究区水化学类型主要为HCO3-Ca和SO4.HCO3-Ca型。区域内地热水中δ18O值为-9.32‰~-6.81‰,δD为-64.4‰~-44.9‰;冷泉及河流中δ18O值为-7.51‰~-6.00‰,δD为-50.7‰~-38.2‰,均分布在我国大气降水线及当地大气降水线附近,表明该地区主要是大气降水成因。通过H、O同位素计算补给区温度,地热水补给高程,以及冷泉及河流补给高程,推测出补给区可能为袍木寨背斜一带及红石走滑断裂及其断裂束附近的碳酸盐岩裸露地区。氚盈余参数d表明石阡地区大多数地热水埋深较浅,循环径流时间较短,地质环境处于开放与半开放之间,水-岩反应作用相对较弱。  相似文献   

承德市臭氧污染气象条件预报方法研究   总被引：1，自引：0，他引：1  

陆倩  王国辉  付娇  周士茹 《气象与环境学报》2019,35(6):67-76

利用2014-2016年承德市环境监测站和气象站的数据,分析了气象条件对承德市O₃-8h浓度的影响,探讨了臭氧污染气象条件的预报方法。结果表明：4-7月是承德市O₃-8h浓度较高的月份,O₃浓度的日变化特征为午后浓度高而夜间浓度低;O₃污染的天气形势为500 hPa受高压脊和偏西气流影响,850 hPa有强暖平流和20℃以上的高温,地面受低压前部和高压后部之间的偏南气流影响;有利于O₃-8h出现高浓度的气象因子为日平均气温大于23℃、日最高气温大于28℃、日平均海平面气压995-1007 hPa、日平均水汽压18-28 hPa、偏南风大于1 m·s^-1。利用气象因子综合评分建立臭氧污染指数,与O₃-8h浓度的相关系数高达0.7553,说明臭氧污染指数能较好地预报臭氧污染天气。  相似文献