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青藏高原地区分布的湖泊数量众多、面积较大、分布范围广泛.受制于恶劣的自然条件,对该地区湖泊的光学吸收特性以及光合有效辐射衰减系数(Kd(PAR))的研究鲜有成果.本文依据2014和2015年间采集的13个典型高海拔、湖泊面积较大的湖库的现场实测数据和实验室测定数据,分析了采样湖库各个采样点的Kd(PAR)特征以及有色可溶性有机物(CDOM)、藻类颗粒物吸收及非色素颗粒物吸收特性,计算并分析了Kd(PAR)与透明度以及光学活性物质的关系.研究结果表明:青藏高原地区各湖库平均各项颗粒物吸收系数均较低,总颗粒物吸收系数在400~700 nm波段内不超过0.14 m~(-1)、CDOM吸收系数在355 nm波长处最高,为1.23 m~(-1)、最低接近于0、藻类颗粒物吸收特性不明显;实验数据完整的巴木错、格仁错和班公错的主导吸收组分各异,其中巴木错为CDOM吸收主导,格仁错与班公错为非色素颗粒物吸收主导;青藏高原采样湖泊总体Kd(PAR)平均值较小,仅为0.26 m~(-1),样点最大值出现在可鲁克湖(1.17 m~(-1)),最小值出现在普莫雍错(0.10 m~(-1));在采样湖泊中Kd(PAR)与透明度呈显著相关;Kd(PAR)与CDOM的相关性最强,叶绿素a浓度次之,与总悬浮颗粒物浓度的相关性最不显著. 相似文献
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蓝藻水华是湖泊水体富营养化的重要特征之一,不同水华蓝藻类群形成的水华特征、危害及其治理方法差异显著.因此,如何快速、准确地掌握不同蓝藻类群的时空分布特征成为实施富营养化湖泊污染治理与生态恢复、蓝藻生态灾害预测预警中一个亟待解决的科学问题.本研究基于纯藻种实验室培养和室内光学控制实验,在微囊藻(Microcystis)、鱼腥藻(Dolichospermum)、束丝藻(Aphanizomenon)3种主要水华蓝藻固有光学特性的基础上,通过甄别不同水华蓝藻的吸收、散射和后向散射光谱的特征波段,构建了基于吸收和散射特性的5种水华蓝藻类群的非线性最优化定量识别模型,其中,基于440、620和675 nm 3个波段吸收的a-CIM 440,620,675具有较为稳定的定量识别能力;并基于野外实测光学特性数据,实现了巢湖主要水华蓝藻类群的定量监测,初步分析了巢湖主要水华蓝藻类群的时空分布特性.研究表明,巢湖的水华蓝藻以鱼腥藻、微囊藻为主,束丝藻较少,鱼腥藻主要出现在温度较低的季节,微囊藻在夏季的西部湖区占优势;巢湖水华主要为微囊藻藻华和鱼腥藻藻华,且浓度较高的蓝藻主要存在于水体表面以下20 cm范围内;微囊藻和鱼腥藻在非藻华断面垂向上均匀分布.本研究可为富营养化湖泊蓝藻水华预测预警以及相关管理部门决策提供重要的理论依据和科学支撑. 相似文献
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富营养化湖泊典型水华蓝藻的固有光学特性 总被引：2，自引：2，他引：0
固有光学特性是水体光学特性的重要内容，掌握富营养化湖泊水体内典型水华蓝藻的固有光学特性，是开展不同水华蓝藻遥感识别的理论基础.利用AC-S吸收衰减仪、BB9后向散射仪，通过实验室纯藻培养，研究微囊藻（Microcystis）、鱼腥藻（Dolichospermum）和束丝藻（Aphanizomenon）3种典型水华蓝藻的固有光学特性，并探讨色素浓度、色素占比以及藻类等效粒径对不同水华蓝藻固有光学特性的影响.结果表明，3种典型水华蓝藻的吸收光谱曲线均具有440、620和675 nm吸收峰，微囊藻620和675 nm的比吸收系数最大，鱼腥藻440 nm处的比吸收系数最大；束丝藻单位色素浓度的散射和后向散射能力最高，鱼腥藻次之，微囊藻最低；固有光学特性影响因子分析表明，色素浓度和藻蓝素占比是影响3种水华蓝藻固有光学特性的主要因素.3种蓝藻的吸收系数、散射系数以及鱼腥藻、束丝藻的后向散射系数均随着色素浓度（叶绿素a或藻蓝素）的增加而增大；当蓝藻中藻蓝素占比增加时，3种蓝藻的单位色素浓度的后向散射系数逐渐下降；而藻细胞粒径与固有光学特性之间并未表现出很好的相关性.因此，3种水华蓝藻单位色素浓度的固有光学特性将为典型水华蓝藻的遥感识别提供重要的理论基础和数据支持. 相似文献
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太湖水体3种典型水质参数的高光谱遥感反演 总被引：7，自引：3，他引：4
以富营养化污染严重的太湖为研究区,设计并实施了2次太湖航空遥感综合实验,获取了太湖7条航带、冬夏两个时相的航空高光谱遥感图像;通过6次太湖地面试验,采集了多时相的太湖水体固有光学量和表观光学量数据,分析了它们的空间分布规律,建立了单化固有光学量数据库;面向叶绿素、悬浮物和黄色物质3种典型水质参数,发展了基于生物光学模型和单位固有光学量数据库的水质参数反演分析方法;利用航空高光谱遥感器Will图像和航天高光谱遥感器CHRIS图像对这些方法进行了检验,获得了较好的水质参数图像反演结果. 相似文献
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世界咸水湖的物理与化学特性 总被引：3，自引：0，他引：3
本文根据近年来有关咸水湖的研究文献,介绍了咸水湖的概念、地理分布和湖盆的成因。进而从咸水湖的光学特性和热学特性两个方面阐述了湖泊的物理特性;从湖水盐度、蒸发和盐度、盐分来源,湖水的化学成分和类型以及盐湖的演化等方面说明咸水湖的化学特点;最后,从盐类沉积和古气候古环境关系的角度出发,指出咸水湖的古湖沼学研究在过去全球变化历史的重建中具有巨大的潜力,是全球研究体系中不可缺少的部分。 相似文献
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生物操纵与非经典生物操纵的应用分析及对策探讨 总被引：8，自引：2，他引：6
分析了生物操纵(biomanipulation)和非经典生物操纵(non-traditional biomanipulation)理论的原理、应用条件及局限性,提出了在局部水体治理湖泊富营养化的对策.分析认为:生物操纵的核心内容是利用浮游动物控制藻类;但浮游动物不能有效控制丝状藻类和形成群体的蓝藻水华;我国的大型浅水湖泊浮游动物数量一般并不多,对浮游植物摄食压力不大;在浅水湖泊,浮游动物摄食藻类后很快分解、释放又进入物质循环,因此不能治理湖泊富营养化;浮游动物是浮游植物和鱼类等经济水生动物之间重要的营养通道,过分追求保护浮游动物是值得思考和研究的问题.而非经典生物操纵的核心内容是利用鱼类直接控制蓝藻水华;当鲢、鳙鱼达到阈值密度可以控制蓝藻水华,但很难控制所有藻类和降低N、P治理湖泊富营养化.在局部水体治理湖泊富营养化的对策是:把鱼类控藻、水生植被恢复和局部水域生态系统重建相结合,形成具有利用与控制蓝藻生产鱼类、吸收氮磷净化水质功能的"水质生物调控单元". 相似文献
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湖泊水质遥感的几个关键问题 总被引：7，自引：4，他引：3
我国目前约有面积大于1km2的湖泊有3000个,绝大部分属高叶绿素和高悬浮物浓度水体,属于典型的Ⅱ类水体,物质组成多样,水体的光学辐射传输复杂,且有大范围的光学浅水.我国的湖泊水质/水色遥感虽然取得了一定进展,但借鉴海洋水色遥感的相关理论和经验,还需要解决以下四个关键问题:1)兼顾海洋沿海水质遥感,发展专用的静止卫星湖泊水质遥感器;2)在当前多光谱遥感资料基础上研发高光谱湖泊水质因子提取的遥感定量化模型,提高反演精度;3)深化湖底底质对湖泊水质/水质遥感影响研究,发展湖底水质遥感反射率精确计算模型;4)发展适用于湖泊水体区域性Ⅱ类水体大气校正方法,并集成反演、遥感产品制作、分发等技术,构建湖泊水体水质/水色业务化运行体系. 相似文献
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Zhi-Ping Mei François J. Saucier Vincent Le Fouest Bruno Zakardjian Simon Sennville Huixiang Xie Michel Starr 《Continental Shelf Research》2010
The effects of colored dissolved organic matter (CDOM) from freshwater runoff and seasonal cycle of temperature on the dynamic of phytoplankton and zooplankton biomass and production in the Gulf of St. Lawrence (GSL) are studied using a 3-D coupled physical-plankton ecosystem model. Three simulations are conducted: (1) the reference simulation based on Le Fouest et al. (2005), in which light attenuation by CDOM is not considered and maximum growth rate (μmax) of phytoplankton and zooplankton are not temperature-dependent (REF simulation); (2) light attenuation by CDOM is added to REF simulation (CDOM simulation); and (3) in addition to CDOM, the μmax of phytoplankton and zooplankton are regulated by temperature (CDOM+TEMP simulation). CDOM simulation shows that CDOM substantially reduces phytoplankton biomass and production in the Lower St. Lawrence Estuary (LSLE), but slightly reduces overall primary production in the GSL. In the LSLE, the spring phytoplankton bloom is delayed from mid-March to mid-April, resulted from light attenuation by CDOM. The CDOM+TEMP simulation shows that the spring phytoplankton bloom in the LSLE is further delayed to July, which is more consistent with observations. Annual primary production is reduced by 33% in CDOM+TEMP simulation from REF and CDOM simulations. Zooplankton production is the same in all three simulations, and export of organic matter to depth is reduced in CDOM+TEMP simulation, suggesting that temperature controlled growth of phytoplankton and zooplankton enhances the coupling between primary production and zooplankton production under the seasonal temperature cycle of the GSL. 相似文献
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太湖秋季真光层深度空间分布及浮游植物初级生产力的估算 总被引：10，自引：5，他引：5
基于2004年10月对全湖67个采样点水下光合有效辐射(photosynthetically active radiation:PAR)和各光学活性物质浓度的测定,分析了真光层深度的空间分布及其影响因素.利用实测的叶绿素a浓度,真光层深度,PAR强度,由水温计算得到的最佳固碳速率以及由经纬度计算的日照周期等,在垂向归纳模型(vertically generalized production model:VGPM)的支持下估算了全湖秋季浮游植物初级生产力.真光层深度的变化范围为0.37-5.27m(均值为1.52±1.06m),高值出现在东太湖、胥口湾、东西山之间等水生植物分布茂盛的草型湖区,而在梅梁湾、湖心区以及西南面的开阔湖区真光层深度均较小.回归分析显示,真光层深度主要受制于非色素颗粒物浓度,浮游植物和溶解性有机物的贡献相对要小得多.叶绿素a浓度和VGPM模型估算的浮游植物初级生产力变化范围分别1.21-53.59μg/L、77.4-2484.9mg/(m2·d),其时空分布基本一致,高值出现在富营养化的藻型湖区梅梁湾,低值出现在胥口湾和西南开阔湖区.VGPM模型和经验模式对比结果显示两者值比较接近并存在显著相关(r2=0.79.P<0.0001).两类模型全湖的均值分别为694.5±492.0、719±84±315.4mg/(m2·d),但由于VGPM模型考虑到真光层深度、温度、PAR强度以及日照周期对初级生产力的影响,其变化范围明显大于经验模型,也更能反映初级生产力的空间变化. 相似文献
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Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance 总被引：5，自引：0，他引：5
ZHANG Yunlin QIN Boqiang HU Weiping WANG Sumin CHEN Yuwei CHEN Weimin 《中国科学D辑(英文版)》2006,49(4):431-442
Euphotic depth can be defined as the portion of wa- ter column that supports the net primary productivity. Its lower end is the critical depth, namely, the depth measured when the daily net primary productivity is zero[1]. In the ecosystems of oceans, lakes and rivers, phytoplankton live in the euphotic depth and euphotic depth is usually taken as the lower boundary, when studying the primary productivity and biomass of phytoplankton; therefore the corresponding depth is sometimes called the t… 相似文献
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Variations in light absorption properties during a phytoplankton bloom in the Pearl River estuary 总被引：1，自引：0，他引：1
From 15 to 28 August in 2007, a Chaetoceros socialis bloom was detected in the Pearl River Estuary water with chlorophyll a concentration (Chl a) up to 30 mg m−3 and cell density up to 106 cells L−1. Time series of bio-optical measurements was obtained at a single site (114.29°E, 22.06°N) with the mooring of marine optical buoy. Light absorption properties of seawater experienced large variability throughout the algal bloom. Absorption by colored dissolved organic matter (CDOM) was one of the dominant optical components of the light absorption (30–70%) especially for pre- and post-bloom waters, and it tended to decrease with Chl a during the algal bloom. Absorption by phytoplankton was another dominant optical component (18–50%) and increased rapidly with Chl a. Phytoplankton and accompanying material played dominant roles in light absorption as indicated by the relationship between absorption coefficient and Chl a. At high pigment concentrations, water samples showed significantly lower specific phytoplankton absorption, compared with pre- and post-bloom conditions, with the specific phytoplankton concentration at 443 nm varied between 0.011 and 0.022 m2 mg−1 and that at 676 nm between 0.007 and 0.018 m2 mg−1; small values of blue-to-red ratio of phytoplankton were also observed. These lower values were associated with variations in phytoplankton size structure. Spectral variability of phytoplankton absorption and total absorption (not including the fixed background absorption by pure water itself) could be expressed as simple linear functions linking absorption at one wavelength to the absorption at the other wavelengths, with the slope of the relationship changing with wavelength. The absorption coefficients by non-algal particles and CDOM follow the general exponential functions with remarkably limited variability in the exponent with means of 0.0105 and 0.0166 nm−1, respectively. These spectral dependencies of absorption coefficients provide useful information for retrieving inherent optical properties from reflectance data in a remote-sensing context. 相似文献
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Based on three continuous in situ underwater light field measurement under different wind waves conditions in Longgan Lake, Meiliang Bay of Taihu Lake in July 2003 and littoral zone near TLLER in July 2004, respectively, the effects of sediment resuspension caused by wind waves on PAR diffuse attenuation, absorption coefficients and euphotic depths are analyzed. In Longgan Lake, PAR diffuse attenuation coefficients during small, middle and large wind waves were 1.74, 2.02 and 2.45 m-1, respectively, and the corresponding PAR spectral diffuse attenuations ranged from 0.98 to 2.97, 1.34 to 3.95 and 1.80 to 5.40 m-1, respectively. In Meiliang Bay, PAR diffuse attenuation coefficients were 2.63, 3.72, 4.37 m-1 during small, middle and large wind waves. PAR diffuse attenuation coefficients increased by 41% and 66% from small to middle, large wind waves, respectively. Absorption coefficients integrated over the range of PAR of CDOM, phytoplankton were 0.26, 0.28 m-1; 0.76, 0.49 m-1, respectively during middle and large wind waves. Absorption coefficients integrated over the range of PAR of non-algal particulate matter and total suspended particulate matter increased from 0.94 to 1.73 m-1, and from 1.70 to 2.22 m-1, respectively during middle and large wind waves. Relative contributions of absorption coefficients of non-algal particulate matter to total absorption coefficient integrated over the range of PAR were 44.14%, 65.05%, respectively, during middle and large wind waves. PAR euphotic depths decreased by 0.40, 0.19, 0.20 m from middle to large wind waves in Longganhu Lake, Meliang Bay and littoral zone near TLLER. Significant correlations were found between transparency, PAR diffuse attenuation coefficients, euphotic depths and total suspended paniculate matter, wind velocity, wave height. Most significant correlations were found between transparency, PAR diffuse attenuation coefficients, euphotic depths and inorganic suspended paniculate matter but low correlations for chlorophyll a, dissolved organic carbon. Increase of total suspended paniculate matter, especially inorganic suspended paniculate matter caused by wind waves was the dominant factor affecting underwater light field in shallow lakes in the middle and lower reaches of the Yangtze River based on observations at three stations. 相似文献
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This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication. 相似文献
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This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled “The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River”. All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication.
相似文献