岩性和种植年限对火龙果地土壤碳、氮、磷生态化学计量特征的影响     

易芬  邓艳  洪涛  谢运球  吴松  柯静 《地质论评》2022,68(6):2219-2232

以石漠化问题突出区域——广西平果县太平镇耶圩火龙果种植园不同岩性背景(白云岩、碎屑岩)和不同种植年限(1、3、5a)土壤为研究对象,采用相关性分析和冗余分析方法探讨了不同岩性背景和火龙果种植年限下土壤碳、氮、磷生态化学计量特征及其影响因素。结果表明：①白云岩区土壤全磷含量显著高于碎屑岩区,而土壤有机碳含量、生态化学计量比(C/N、C/P和N/P)显著低于碎屑岩区;且白云岩和碎屑岩背景下的生态化学计量比(5. 96、11. 78、1. 96和8. 71、19. 78、2. 28)均远低于全国水平。②随着火龙果种植年限的增加,土壤有机碳、全氮含量和C/N、C/P、N/P呈现出逐渐增加的趋势,而土壤有效氮、全磷和有效磷含量无显著变化规律。随着土层深度增加,土壤有机碳、全氮、有效氮含量和C/N、C/P、N/P均增加,而土壤全磷含量无明显变化规律。③土壤C/N和C/P与有机碳、有效氮均呈显著正相关(P<0. 01),而与土壤水分、容重呈显著负相关,土壤N/P与全磷呈显著负相关。④冗余分析表明不同岩性背景和火龙果种植年限下土壤有效氮含量是土壤碳、氮、磷及其生态化学计量比的重要影响因子,且呈显著正相关关系(P<0. 01)。白云岩背景下火龙果的生长受到氮元素的影响更大,长期火龙果种植有利于碳、氮元素固存,土壤有效氮含量是影响土壤碳、氮、磷及其生态化学计量比的关键因子。  相似文献   

复合解堵技术在天然气水合物开发中的应用可行性分析          下载免费PDF全文

史浩贤  谢文卫  于彦江  钟奕昕  史志习 《探矿工程》2022,49(1):5-15

不同物质如地层颗粒、微生物、注入物等在流固运移、滞留过程中,会造成油气井的堵塞,本文对堵塞区域进行划分,分为地面集输管线堵塞、井筒堵塞、挡砂介质堵塞及地层孔道堵塞4类。阐述造成堵塞的物理、化学、生物等因素及堵塞特征。梳理现阶段海洋油气资源开发过程中常用的解堵工艺技术现状,将解堵技术分为物理、化学、生物、复合4类。同时分析认为复合解堵技术在未来应用于天然气水合物开发中的可能性最大,为今后海域天然气水合物资源开发中解堵技术提供参考。  相似文献   

Effect of groundwater on the ecological water environment of typical inland lakes in the Inner Mongolian Plateau          下载免费PDF全文

Chu Yu  Li-jie Wu  Yi-long Zhang  Xiu-ya Wang  Zhan-chuan Wang  Zhou Zhang 《地下水科学与工程》2022,10(4):353-366

To explore the causes of the ecological environment deterioration of lakes in the Inner Mongolia Plateau, this study took a typical inland lake Daihai as an example, and investigated the groundwater recharge in the process of lake shrinkage and eutrophication. Using the radon isotope (²²²Rn) as the main means of investigation, the ²²²Rn mass balance equation was established to evaluate the groundwater recharge in Daihai. The spatial variability of ²²²Rn activity in lake water and groundwater, the contribution of groundwater recharge to lake water balance and its effect on nitrogen and phosphorus pollution in lake water were discussed. The analysis showed that, mainly controlled by the fault structure, the activity of ²²²Rn in groundwater north and south of Daihai is higher than that in the east and west, and the difference in lithology and hydraulic gradient may also be the influencing factors of this phenomenon. The ²²²Rn activity of the middle and southeast of the underlying lake is greater, indicating that the ²²²Rn flux of groundwater inflow is higher, and the runoff intensity is greater, which is the main groundwater recharge area for the lake. The estimated groundwater recharge in 2021 was 3 017×10⁴ m³, which was 57% of the total recharge to the lake, or 1.6 times and 8.1 times that of precipitation and surface runoff. The TN and TP contents in Daihai have been rising continuously, and the average TN and TP concentrations in the lake water in 2021 were 4.21 mg·L^?1 and 0.12 mg·L^?1, respectively. The TN and TP contents entering the lake with groundwater recharge were 6.8 times and 8.7 times above those of runoff, accounting for 87% and 90% of the total input, respectively. The calculation results showed that groundwater is not only the main source of recharge for Daihai, but also the main source of exogenous nutrients. In recent years, the pressurized exploitation of groundwater in the basin is beneficial in increasing the groundwater recharge to the lake, reducing the water balance difference of the lake, and slowing down the shrinking degree of the lake surface. However, under the action of high evaporation, nitrogen and phosphorus brought by groundwater recharge would become more concentrated in the lake, leading to a continuous increase in the content of nutrients and degree of eutrophication. Therefore, the impact of changes in regional groundwater quantity and quality on Daihai is an important issue that needs further assessment.  相似文献   

基于光谱特征空间的监督分类中包络线去除效能评价          下载免费PDF全文

王霄鹏  张杰  任广波  马毅 《海洋科学进展》2015,33(2):195-206

对覆盖黄河口滨海湿地的PROBA CHRIS高光谱遥感影像进行包络线去除变换,采用6种常用的基于光谱特征空间的监督分类算法对变换前后的影像数据进行滨海湿地典型地物分类,通过目视对比分析和定量分析相结合的方法分析比较变换前后的分类结果,评价包络线去除方法对该类算法影响的效果和能力。结果表明,包络线去除方法能够提高部分监督分类算法针对滨海湿地典型植被类型的区分和识别能力;但由于滨海湿地内具有面积较大的裸滩和浑浊水体,这两类地物在影像中的光谱特征相近,而包络线去除方法并不能解决二者的误分问题,因此并不能提高该类算法针对CHRIS高光谱遥感影像的总体分类精度。  相似文献   

三疣梭子蟹、凡纳滨对虾和菲律宾蛤仔混养系统氮磷收支的研究     

张凯  田相利  董双林  董佳  奉杰  何瑞鹏  闫法军 《中国海洋大学学报(自然科学版)》2015,45(2):44-53

利用海水池塘陆基实验围隔,研究三疣梭子蟹(Portunus trituberculatus)、凡纳滨对虾(Litopenaeus vannamei)和菲律宾蛤仔(Ruditapes philippinarum)不同混养系统的养殖效果以及氮(N)和磷(P)的收支和利用率状况。结果表明:(1)适宜的三疣梭子蟹、凡纳滨对虾和菲律宾蛤仔三元混养,能有效提高三疣梭子蟹养殖的综合效益。(2)投喂的饵料(包括对虾配合饲料与蓝蛤(Aloidis laevis))是系统N、P的主要来源,占N总输入量的84.41%~89.75%和P总输入量的96.64%~98.35%;其次为水层中带入的N、P,占N总输入量的7.14%~11.97%和P总输入量的0.39%~1.11%。N、P的支出主要为底泥积累,占N总支出量的39.88%~57.17%和P总支出量的35.69%~68.45%;其次为养殖生物收获N、P,占总支出的比例分别为16.86%~32.24%和18.72%~33.55%;N的输出渗漏损失较大,水层积累较少,而P的输出水层积累较多,渗漏损失较少。(3)各处理比较,三元混养PLR3组N的利用率显著提高,比其它处理提高了9.95%~15.80%。综合养殖效果和各系统N、P利用率结果,在本研究条件下,蟹、虾、贝混养最优比例为三疣梭子蟹6ind/m2、凡纳滨对虾45ind/m2、菲律宾蛤仔30~60ind/m2。  相似文献   

Use of turbidometry to characterize suspended sediment and phosphorus fluxes in the Lake Tahoe basin,California, USA     

Andrew P. Stubblefield  John E. Reuter  Randy A. Dahlgren  Charles R. Goldman 《水文研究》2007,21(3):281-291

The efficacy of in‐stream nephelometric turbidometry as a surrogate for total suspended solids (TSS) and total phosphorus (TP) concentrations was evaluated for use in low turbidity (<50 NTU) subalpine watersheds at Lake Tahoe, California–Nevada, USA. Continuous turbidity records for the 1999, 2000 and 2001 snowmelt seasons and data from water quality samples (1982–2000) were examined to determine watershed sediment delivery dynamics. Strong correlations were found between turbidity and both TSS and TP concentration. The strong correlation indicates that turbidity can serve as a good surrogate for direct measurement in these watersheds. The watersheds displayed clockwise hysteresis: sediment flushing and depletion, on daily, seasonal and decadal time‐scales. The hysteresis curves had strong concave shapes, indicating a sensitive response to peak flow. A pronounced seasonal trend was observed for the ratio of suspended sediment concentration (SSC)/discharge over time, indicating early season flushing of available sediment. Significant linear relationships (p < 0·05) were found for 12 of 17 years. Comparison of annual sediment rating curve coefficients indicated smaller coefficients during high sediment loading years and in the years following. The smaller coefficients are evidence of sediment depletion during high flow years. The effect of hysteresis on monitoring methods was illustrated by comparing turbidity estimates of TSS load with sediment rating curve estimates of SSC. After accounting for differences in SSC/TSS methods of analysis, daily loads calculated with turbidity methods were 58–98% of rating curve estimates for the spring snowmelt seasons of 1999–2001. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

The effects of different input data and their spatial resolution on the results obtained from a conceptual nutrient emissions model: the River Stör case study     

Markus Venohr  Horst Behrendt  Winfrid Kluge 《水文研究》2005,19(18):3501-3515

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东太湖河流水生植物群落对磷及有机质的生态效应   总被引：1，自引：0，他引：1  

徐德兰  雷泽湘  王晓  韩宝平  刘正文 《海洋湖沼通报》2008,(4)

河流是湖泊生态系统的重要组成部分,也是物质运移的重要通道。沉积物中的TP及其有机质(SOM)含量对湖泊生态系统有着重要影响,也是衡量该系统健康状况重要标志。本文通过对太湖的入湖河流及其与太湖交汇区域不同植物群落沉积物中总磷、有机质含量分析,结果表明:河流沉积物TP含量高于湖泊沉积物,是其1~2倍,SOM远低于其与湖泊交汇处沉积物的含量。而TP与SOM二者相关不显著,河流沉积物及其与太湖交汇区沉积物TP及SOM二者相关不显著,但方差分析表明两者差异性显著(P<0.05)。  相似文献   

Detection of acid rain stress effect on plant using hyperspectral data in Three Gorges region, China   总被引：2，自引：0，他引：2  

Xiaodong Song  Hong Jiang  Shuquan Yu  Guomo Zhou 《中国地理科学(英文版)》2008,18(3):249-254

This paper aims to use hyperspectral data to detect the spectral change caused by acid stress to a native forest type in the Three Gorges region of China. For this purpose, a ground-based hyperspectral experiment was conducted at the Three Gorges region to detect acid deposition that caused Masson pine （Pinus massoniana） forest degradation. Continuum removal method was used to isolate wavebands more responsive to stress in wavelengths 450-750nm. The differences in chlorophyll concentrations and needle thickness caused by acidic stress are found to be explicable to the different spectral reflectance patterns in the visible and near-infrared wavelengths. Two new chlorotic indices were utilized to explain the stress-caused leaf chlorosis. The comparison of simulated vegetation indices and principal component analysis （PCA） results suggests that it would be possible to monitor acid rain stress effect on forest ecosystem from some wider spectral regions.  相似文献   

砖红壤速效磷3种测定方法的比较     

凌大炯  李燕 《广东海洋大学学报》1999,(3)

用Ｏｌｓｅｎ、Ｂｒａｙ－１ 和Ｍｅｈｌｉｃｈ－３ 三种方法对不同植被下的砖红壤进行速效磷的测定比较。结果表明：种植橡胶的土壤磷，Ｂｒａｙ－１ 法和Ｍｅｈｌｉｃｈ－３ 法间有较好的一致性，且呈显著相关；种植甘蔗的土壤磷，三种方法间均呈极显著相关；而种植其它植物的土壤磷，方法间的一致性较差，相关也不显著。一般情况下，建议不要用Ｍｅｈｌｉｃｈ－３ 作为砖红壤速效磷的提取剂。  相似文献