Network analysis to inform invasive species spread among lakes     

ESCOBAR Luis E.  ROMERO-ALVAREZ Daniel  LARKIN Daniel J.  PHELPS Nicholas B. D. 《海洋湖沼学报（英文）》2019,(3):1037-1041

Often facilitated by human-mediated pathways,aquatic invasive species are a threat to the health and biodiversity of global ecosystems.We present a novel approach incorporating survey data of watercraft movement in a social network analysis to reconstruct potential pathways of aquatic invasive species spread between lakes.As an example,we use the green alga Nitellopsis obtusa,also known as starry stonewort,an aquatic invasive species affecting the Great Lakes region in the United States and Canada.The movement of algal fragments via human-mediated pathways(i.e.,watercraft)has been hypothesized as the primary driver of starry stonewort invasion.We used survey data collected at boat ramps during the 2013 and 2014 openwater seasons to describe the flow of watercraft from Lake Koronis,where N.obtusa was first detected in Minnesota,to other lakes in the state.Our results suggest that the risk of N.obtusa expansion is not highly constrained by geographic proximity and management efforts should consider highly connected lakes.Estimating human movement via network analysis may help to explain past and future routes of aquatic invasive species infestation between lakes and can improve evidence-based prevention and control efforts.  相似文献   

A Raman investigation on the boron form occurring in salt lake brine during evaporation     

彭姣玉  陈婧  王兴鹏  董亚萍  李武 《盐湖研究》2019,27(1)

Boron resources are abundant in Da Qaidam salt lake of Qaidamu Basin. It has been given great attention for the polyborate species present in brine. In this study, the Raman spectroscopy was applied to investigate the existing-form of boron in brine during evaporation. The prepared solutions of MgO·2B2O3-H2O, MgO·2B2O3-MgCl2 -H2O, and MgO·2B2O3-MgSO4-H2O was also evaporated and recorded to study the influence of boron concentration, pH, and electrolytes on the borate speciation in brine. The mononborates of B(OH)3 and B(OH)4- were found to be the only forms present in the original salt lake brine. Brine evaporation promotes the formation of polyborate anions B3O3(OH)4-, B5O6(OH)4-, and B6O7(OH)62- and also disappearance of the B(OH)4- ion in brine with boron concentration of more than 11 g/L in B2O3. The pentaborate ion of B5O6(OH)4- was sensitive to the solution pH and found to be appeared under the pH value of 8.0. While the hexaborate ion of B6O7(OH)62- was observed more dependent on the electrolyte of magnesium chloride due to its special properties, such as promoting boron accumulation, lowering solution pH, and also the strong af?nity for water molecules, which is beneficial to the polymerization of borate ions in brine. The interaction mechanisms among polyborate anions during evaporation had also been proposed.  相似文献   

Spatiotemporal characteristics of Qinghai Lake ice phenology between 2000 and 2016     

Qi  Miaomiao  Yao  Xiaojun  Li  Xiaofeng  Duan  Hongyu  Gao  Yongpeng  Liu  Juan 《地理学报(英文版)》2019,29(1):115-130

Journal of Geographical Sciences - Lake ice phenology is considered a sensitive indicator of regional climate change. We utilized time series information of this kind extracted from a series of...  相似文献   

Lakes of the Jom-Bolok Volcanoes Valley in the East Sayan Mts., Baikal region     

Shchetnikov  Alexander  Bezrukova  Elena V. 《地理学报(英文版)》2019,29(11):1823-1840

Journal of Geographical Sciences - This article describes the lake basins of the Jom-Bolok volcanic region in the East Sayan (the largest manifestation of the Holocene eruptions in Central Asia)....  相似文献   

A geospatial study of the drought impact on surface water reservoirs: study cases from Texas,USA     

Zachary Asbury 《地理信息系统科学与遥感》2019,56(6):894-910

Satellite images have been used historically to measure and monitor fluctuations in the surface water reservoirs. This study integrates remote sensing and Geographic Information System (GIS) technologies to investigate the impact of drought on 10 selected surface water reservoirs in San Angelo and Dallas, Texas. Oscillations in summer and winter months throughout the 2005–2016 period were assessed using multispectral images from Landsat-5, ?7, and ?8, and changes in the reservoirs were characterized and correlated against local climate data of each reservoir. For quantitative comparisons of the time-series measurements, a robust density slicing approach was employed to classify the range of values of the raster cells in the near-infrared band of Landsat images for each lake into three desired classes (deep water, shallow water, and dry area) based on the natural breaks inherent in the dataset. Statistical analysis shows that the overall accuracy of the classification is about 94%, which demonstrates the efficiency of the density slicer to accurately estimate surface water area changes from an individual Landsat band. Shrinkage in the surface water area over the study period reveals the concrete impact that the drought along with other factors have on the 10 selected lakes. The San Angelo lakes located in west central Texas experienced a nearly consistent pattern of change during most of the study period; whereas the Dallas lakes in northeast Texas followed the oscillating pattern of drought and correlated closely to the local conditions. Shockingly, the extreme drought caused complete vanishing of several lakes, and consequently Texas had to remove them from its recreational plans. Our new findings can certainly help with the water resource management in Texas and our study approach can be adapted for monitoring lake oscillations in other areas across the world. This geospatial study demonstrates the societal benefits from incorporating remote sensing and GIS in investigating geo-environmental problems associated with severe climate changes.  相似文献   

腾格里沙漠西北缘湖泊沉积记录的全新世中期气候环境   总被引：4，自引：0，他引：4  

隆浩  马海州  王乃昂  李育  王晨华 《海洋地质与第四纪地质》2007,27(3):105-111

通过腾格里沙漠西北缘青土湖沉积物粒度、有机碳、碳酸盐、碳氮比和有机质稳定同位素等多项沉积学气候代用指标及精确定年的综合分析,建立了该区域全新世中期9.0~3.0 cal.kaBP的古气候演化序列。结果表明,9~7.8 cal.kaBP期间,区域的水分条件和温度逐渐上升,植被状况好转,此阶段属于全新世早期向全新世暖湿期转变的过程;而在7.8~7.5 cal.kaBP期间出现了显著的百年尺度的干旱事件,沉积物主要以砂质沉积为主,此时湖泊生产力显著下降;全新世期间最为暖湿的气候适宜期出现在7.5~5.0 cal.kaBP;5.0 cal.kaBP以来,该区域出现了较为明显的干旱化趋势。  相似文献   

15-20世纪大陆泽与宁晋泊演变的影响因素分析   总被引：1，自引：0，他引：1  

石超艺 《湖泊科学》2007,19(5):522-529

15至20世纪,海河流域南系历史上著名的湖泊--大陆泽和宁晋泊经历了从宽广到干涸的巨大变迁.对于二泊演变的原因,此前学者从未做过专门的分析和研究.本文以明清时期丰富的历史文献为依据,对影响湖泊演变的各大自然和人文因子进行了深入探讨,得出如下基本结论:海河南系水系格局不断变迁导致湖泊水源补给发生迅速改变,是促使湖泊相应发生显著扩张与萎缩,并最终导致湖泊消亡的直接主要动因.此外,来自河流的泥沙淤积,气候的干湿变化,人类拦水筑坝、占垦涸泊等活动加速了湖泊的演变与消涸.  相似文献   

人类活动和气候变化对艾比湖湖泊面积的影响   总被引：11，自引：0，他引：11  

周驰  何隆华  杨娜 《海洋地质与第四纪地质》2010,(2)

新疆艾比湖地处我国西北干旱区,为典型的内陆封闭性湖泊,由于受内陆极端干旱气候及人类活动的影响,导致湖泊面积显著变化。湖泊面积变化所导致的生态环境恶化已成为制约当地社会经济发展的重要因素。以不同年份的多源遥感数据为数据源,分析了1972—2008年湖泊面积变化情况,并分析了特征年内湖泊面积变化的原因。认为气候要素中降水对湖泊面积影响较大,另外,人类活动引起绿洲变化,而绿洲农业灌溉用水对湖泊面积变化影响较大。同时,还分析了湖泊萎缩引起的湖泊水质恶化以及湖滨植被退化和区域沙漠化等环境效应,结果表明,湖泊面积是流域生态保障的重要指标,可作为反应湖泊流域生态情况的重要指标。由此提出了保护艾比湖生态环境的若干建议。  相似文献   

云南程海近500年来湖泊初始生产力的演化   总被引：14，自引：1，他引：14  

吴敬禄  蒋雪中  夏威岚  潘红玺  尹宇 《海洋地质与第四纪地质》2002,22(2):95-98

程海为富营养化封闭湖泊，通过对程海CH01乳沉积物色素分析，定性恢复了近500a来程海湖泊初始生产力演化过程，结果表明，近500a来程海湖泊初始生产力总体上呈现由低到高的上升趋势，其中1700AD前后，1790AD前后是湖泊初始生产力出现变化的界限，另外，色素含量变化揭示研究时期内存在1750AD前后，1930AD前后二次明显暖波动。  相似文献   

新疆罗布泊盐湖卤水资源综合开发研究   总被引：12，自引：3，他引：12  

李浩  唐中凡  刘传福  雷光元 《地球学报》2008,29(4):517-524

罗布泊盐湖赋存有丰富的含钾硫酸镁亚型卤水,现已探明仅罗北凹地区段孔隙度储量2.67×109t(折合KCl),属特大型钾盐卤水矿藏,是生产硫酸钾的理想原料;此外,卤水中含有丰富的钠、镁、锂、硼等资源,综合回收利用价值较大。本文针对罗布泊盐湖卤水资源,在有效利用盐湖钾资源同时,加快其他共生资源的综合开发进程,将新疆罗布泊盐湖资源开发建设推向持续、合理、有效、高值的循环经济发展的道路,为国家西部经济开发做出贡献。  相似文献