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1.
太湖蓝藻爆发与水温的关系的MODIS遥感 总被引：15，自引：4，他引：11
利用MODIS高光谱遥感数据动态监测太湖地区蓝藻水华发展过程,并结合水温环境因子,探讨蓝藻爆发的环境条件.首先,通过简单的比值植被指数,实现蓝藻生物量的遥感估算;根据六期遥感估算结果,监测太湖蓝藻动态发展过程.然后,利用MODIS热红外波段(31和32),采用分裂窗算法,同步反演出的太湖表面水体温度,探讨蓝藻爆发的水温条件,及蓝藻生长与水-温度之间的关系.研究结果表明,在水体富营养化前提下,水体温度是影响蓝藻生长的重要环境因子;合适的水体温度(24-30℃)是蓝藻爆发的必要条件;大于30℃的高温,对蓝藻的生长有明显的抑制作用. 相似文献
2.
附着生物对太湖常见的两种沉水植物快速光曲线的影响 总被引：5，自引：2，他引：3
在水草生长比较旺盛的季节(7-8月),以水草较丰富的贡湖湾作为采样区域,野外采样结合室内分析研究太湖常见的两种沉水植物马来眼子菜(Potamogeton malaianus)及穗花狐尾藻(Myriophyllum spicatum)叶上的附着生物的生物量;利用脉冲振幅调制叶绿素荧光仪研究去除附着生物前后两种沉水植物的光合作用的变化.结果表明,马来眼子菜和穗花狐尾藻两种沉水植物上的附着生物的现存量存在显著的差异,附着生物群落中自养生物与异养生物的比值没有显著差异;两种沉水植物在去除附着生物前后的光合参数有显著的变化,光合作用效率、半饱和光强、最大电子传递速率增加.这表明附着生物降低了沉水植物光合作用. 相似文献
3.
以洞庭湖典型湿地植物辣蓼为目标植物,短尖苔草为邻近植物,通过控制实验研究不同水位(30、0和-30 cm)和竞争(无竞争、全部竞争、地上竞争和地下竞争)模式下目标植物生长及生态化学计量特征的变化.结果表明:水位处理显著影响不同竞争模式下的生物量积累,辣蓼生物量随水位增加显著降低;-30 cm水位无竞争模式下生物量最大,为10.84±1.52 g.在30 cm和0 cm水位梯度下,不同竞争模式下的生物量间无显著差异.但-30 cm水位下,地下竞争模式下的辣蓼生物量积累较全竞争模式和地上竞争模式下显著增多,说明非胁迫条件下,辣蓼和苔草的竞争以地上竞争为主.水位处理对辣蓼叶片、茎和根的氮、磷含量影响显著,30 cm水位下,叶片氮、磷含量显著高于其他水位下的含量.在-30cm水位下,叶片C∶N和C∶P显著高于其他水位下的比值,分别为48.08±3.85、590.3±43.4.相比于对照处理(无竞争),竞争作用下的辣蓼总氮含量降低,而C∶N值增加,N∶P值降低,这可能是因为竞争作用导致辣蓼对氮的吸收减少所致. 相似文献
4.
为研究不同水位上升速度对黑藻生长的影响,本研究采用吊盆悬挂方式模拟不同水位上升速度,将栽种黑藻的吊盆以不同的速度(10、30、50和70 cm/5 d)往下降,分别记为T1、T2、T3、T4实验组.实验共进行80 d.结果表明:不同水位上升速度对黑藻株高影响极显著,各组株高排序为T3组>T2组>T1组>T4组.T2、T3组株高与稳定组差异不显著;T3组株高生长速率达3.7 cm/d;而T4组在实验第49 d完全死亡.水位上升对黑藻分枝数影响显著,分枝数随水位上升速度增大呈递减趋势,且明显少于稳定组.不同水位上升组茎节数、叶片数和节间距均差异显著.随着水位上升速度增加,黑藻茎节数先增后减,叶片数变少,而节间距不断延长;与稳定组相比,茎节数和叶片数减少,而节间距显著延长.水位上升速率增加,黑藻生物量呈递减趋势且差异极显著,水位上升降低了黑藻生物量.黑藻有较强的应对水位上升的能力,其通过改变植株形态,以最大限度地获取光照;但在适应水位上升过程中消耗了一部分光合作用形成的物质,从而使生物量下降.黑藻对水位上升有一定的耐受范围.当水位上升达到70 cm/5 d时,黑藻因无法适应低光照胁迫而死亡. 相似文献
5.
淹水对菖蒲萌发及幼苗生长的影响 总被引：2，自引：0，他引：2
应用盆栽试验方法,研究了菖蒲在不同淹水深度下的萌发和幼苗生长.试验共设20、40、60、80、100和120 cm等6个处理,处理时间为86 d.结果表明:(1)不同淹水深度对菖蒲萌发和幼苗有不同程度的影响,在持续完全淹水条件下,菖蒲幼苗的萌发率仅为淹水20 cm条件下的1/3,幼苗的平均高度为淹水20 cm条件下的1/3左右;(2)菖蒲幼苗叶片长度、宽度、叶片面积和基茎随淹水深度增加而减小,叶片数量和叶片含水率随淹水深度增加而增大;(3)在试验的27 d、54 d、86 d,各淹水深度植物的根、茎、叶及总生物量都比淹水20 cm有不同程度的降低,并随淹水时间的延长,各淹水深度条件下的生物量差别增大.在不同淹水深度条件下,根、茎和叶生物量增量均表现为茎的最多,叶的次之,根的最少;(4)菖蒲幼苗在水深为100-120 cm的逆境条件下时,叶片细胞膜脂过氧化加剧,细胞质膜透性增加;(5)菖蒲幼苗叶片的叶绿素a、b含量和类胡萝卜素(Car)含量随淹水深度的增加而下降;(6)Fv/Fm、ETR、qP随淹水深度的增加而下降,长时间(54-86 d)完全淹水(水深100-120 cm)对菖蒲幼苗光合系统PSⅡ有显著影响,影响菖蒲幼苗PSⅡ的非循环光合电子传递速率,天线色素吸收的光能用于光化学电子传递的份额减少,参与CO2固定的电子减少;qN在54 d、86 d的都有不同程度的增加,菖蒲叶片PSⅡ系统没有遭到破坏. 相似文献
6.
通过室内纯培养,分别设定不同温度梯度(14、16、18℃)和光照梯度(100、250、360 μmol/(m2·s)),以模拟全球气候变化条件下,温带湖泊春季温度升高与光照减弱交互作用对铜绿微囊藻和蛋白核小球藻生长和光合活性的影响.通过流式细胞计数测定其生长曲线,观测其变化趋势,并利用叶绿素荧光仪PHYTO-PAM测定藻类光合活性.结果表明,当温度为18℃,光强为100μmol/(m2·s)时,铜绿微囊藻生长速率最大,细胞密度达到2.99×106cells/ml.在该温度和光照强度下,其光合活性也远高于其他实验组,其Fv/Fm值达到最大值0.39.蛋白核小球藻在温度为16和18℃时,其生长速率差异不大,但明显高于在温度为14℃时的生长速率,其光合活性处于波动状态.与蛋白核小球藻相比,温度升高和光照减弱对铜绿微囊藻生长和光合活性的促进作用更为明显,而且随着温度的升高,铜绿微囊藻生长对低光的偏好更为显著.因此,全球变暖所导致的高温低光环境可能有利于确立铜绿微囊藻在湖泊中的优势地位. 相似文献
7.
水草腐烂引发的黑臭水体应急处置技术研究 总被引：3，自引：0，他引：3
水草腐烂加速水体耗氧和水体还原性物质的溶出进程,在夏、秋季高温条件下极易引发局部水体黑臭.以太湖沉水植物优势种马来眼子菜(Potamogeton malaianus)、苦草(Vallisneria natans)及浮叶植物优势种莕菜(Nymphoides peltatum)为受试材料,利用太湖原位底泥培养模拟水草腐烂形成的黑臭水体,考察不同的环境材料处置方式(壳聚糖(CTS)、聚合氯化铝(PAC)、聚丙烯酰胺(PAM)、CTS+PAC和PAC+PAM)对黑臭水体浊度、溶解氧浓度、挥发性硫化物等黑臭水体特征污染物的絮凝沉降规律及去除机理.结果表明:(1)絮凝处理24 h后,CTS+PAC组合对黑臭水体的浊度去除效果最佳,浊度去除率达70.3%,上覆水溶解氧浓度明显提高,增加率为261.5%;(2)加石英砂悬浊液加速絮体沉淀,形成絮体之后加石英砂使水体浊度稳步下降,4 h之后,浊度去除率达74.9%,显著高于与絮凝剂一起加入的处理组(29.8%);(3)植物腐烂释放的含硫特征嗅味物质主要为硫化氢(H_2S)、甲硫醚和二甲基三硫醚.不同植物体腐烂释放的含硫挥发性有机物浓度差异显著,马来眼子菜释放的4种含硫有机物总和分别为莕菜和苦草释放的319.8%和252.2%;(4)CTS+PAC处理后苦草及马来眼子菜腐烂水体中挥发性有机硫化物浓度较对照组分别降低了18.6%和44.5%.PAC+PAM组合絮凝处理组对莕菜腐烂水体中H2S有较好的去除效果,去除率达到52.4%.CTS+PAC絮凝剂组合处理的H2S浓度均低于对照组,苦草、马来眼子菜和莕菜腐烂后黑臭水体中H2S浓度分别降低了27.4%、41.0%和28.6%.CTS+PAC组合对H2S和二甲基硫醚类物质等致臭物释放的抑制效果优于PAC+PAM组合絮凝处理. 相似文献
8.
蓖齿眼子菜的光合速率及影响因素 总被引：10，自引：2，他引：8
本文研究了蓖齿眼子菜(Potamogeon pectinatus L)在滇池的光合速率、体内叶绿素季节变化及光和水温对其光合速率影响,并根据实验,计算出了蓖齿眼子菜生长的光补偿点,研究结果表明,蓖齿眼子菜1～3月份的净光合产氧量最大,为1.82～1.83mg/(g·h),6月份最低,为0.63 mg/(g·h);植物体内Chl.a和Chl.b平均含量分别为0.25～1.15mg/(g·h)和0.28～0.85mg/(g·h),蓖齿眼子菜可以通过调节体内Chl.a/Chl.b值来适应不同季节生长;蓖齿眼子菜有较宽的水温适应范围,10℃时的净光合产氧量可达0.88mg/(g·h),最高值出现在水温25℃,为1.16mg/(g·h),而30℃以上的水温已表现出对其生长的不利影响;蓖齿跟子菜生长的光补偿点为358～1256Lx,并随温度上升而逐渐增加. 相似文献
9.
环境胁迫对水生植物根系分泌小分子量有机酸(LMWOAs)的影响特征 总被引：1，自引：0，他引：1
本文首次对马来眼子菜(Potamogeton malaianus)、苦草(Vallisneria natans)、芦苇(Phragmites australis)、菖蒲(Acorus calamus)、荇菜(Nymphoides peltatum)和菱角(Trapa incisa) 6种水生植物根系小分子量有机酸(Low Molecular Weight Organic Acids,LMWOAs)分泌差异性及其对环境胁迫(温度、缺磷和高铵态氮)响应特征进行研究结果证实6种受试植物根系分泌LMWOAs组成和含量具有明显的物种差异性;其中,甲酸、乳酸和草酸为主要有机酸温度可显著影响水生植物根系LMWOAs分泌量而对种类影响不大,高温(30℃)刺激莕菜根系LMWOAs分泌量增加,但却明显抑制苦草和菖蒲根系LMWOAs分泌; 25℃时马来眼子菜、芦苇和菱角根系LMWOAs分泌量最多缺磷和高铵态氮胁迫均会显著影响水生植物根系LMWOAs分泌量和种类缺磷胁迫促进苦草、菖蒲和莕菜根系LMWOAs分泌量增加68.68%、55.30%和257.82%,并刺激乙酸和苹果酸等有机酸分泌;而缺磷胁迫可导致马来眼子菜、芦苇和菱角根系LMWOAs分泌量降低38.72%、13.79%和58.99%,且乳酸、甲酸和丁二酸分泌完全被抑制;这表明苦草、菖蒲和莕菜三者能较好的适应缺磷环境高铵态氮胁迫下苦草根系LMWOAs分泌量和种类增加明显;而其余5种受试植物在高铵态氮胁迫下根系LMWOAs分泌量被明显抑制,尤其是乳酸、苹果酸和酒石酸含量显著降低综上所述,水生植物分泌LMWOAs特征差异性显著,可在一定程度上反映其耐逆境胁迫能力,本文结果将为水生植物生态修复机理和实践提供重要理论依据. 相似文献
10.
太湖沉积物-水界面生源要素迁移机制及定量化——1.铵态氮释放速率的空间差异及源-汇通量 总被引：33，自引：0，他引：33
采集柱状芯样,室内静态模拟不同温度下太湖沉积物铵态氮释放.结果表明,经面积加权,5℃、15℃和25℃下氮的交换速率分别为-16.0±17.6mg/穴m2·d雪、12.6±6.9mg/穴m2·d雪和34.1±20.8mg/穴m2·d雪,不同湖区其释放速率差异极大.受外源污染影响较大的水域,氮释放量随温度的升高而增加;受死亡残体沉降和分解影响明显的草藻型湖区,氮的年释放通量较大.全太湖沉积物-水界面NH4 -N的年净通量为9960.3±4960.0t,其中成汇的通量值约为-911±637.9t/a,大部分泥区在一年中至少经过了一次的源-汇转换过程. 相似文献
11.
Yogui GT Santos MC Bertozzi CP Sericano JL Montone RC 《Marine pollution bulletin》2011,62(12):2666-2670
Limited information is available in the literature on the levels of brominated flame retardants in the southern hemisphere. This study presents concentrations of polybrominated diphenyl ethers (PBDEs) in the blubber of small cetaceans from the coast of São Paulo (Brazil), southwestern Atlantic. PBDE levels were highest in Stenellafrontalis (770 ng g−1 lipid) followed by Stenobredanensis (475 ng g−1 lipid), Sotaliaguianensis (65.6 ng g−1 lipid), Tursiopstruncatus (64.2 ng g−1 lipid) and Pontoporiablainvillei (60.3 ng g−1 lipid). In general, continental shelf individuals exhibited higher contamination than inshore animals. This might be related to larger prey items consumed by continental shelf dolphins. The pattern of contamination indicates that Penta-BDE commercial mixtures are a major source of PBDEs to top predators in the southwestern Atlantic. Congeners found in Octa-BDE formulations were not detected in the investigated animals. 相似文献
12.
Floristic surveys, vegetation mapping, and detailed transect analyses rendered a macrophyte flora of 14 native and five alien taxa of flowering plants in the River Erft, a contributory of the River Rhine in Northrhine-Westphalia. Water temperatures of this river do not fall below 10 °C all the year round, for reasons of geothermically heated water discharged from nearby opencast mining areas. Macrophyte stand structures, composed of the neophytes Azolla filiculoides and Lemna minuta (floating) and Myriophyllum aquaticum, Egeria densa, and Vallisneria spiralis (rooted in the muddy or sandy ground of the river) are described and the ecological requirements of these taxa are characterized. The alien species can be seen as elements that increase the α-diversity of the aquatic vegetation of the River Erft. They do not replace any of the native species, even if shifts in the competition dynamics occur. The colonization by neophytes of the abnormally warmed River Erft can be appreciated as paradigmatic for trends in the macrophyte vegetation of medium-sized rivers in Central Europe when climate-related or discharge-based heating of the waterbody occurs and propagules of alien plants imported by waterfowl or – more important – plants from aquarium waste will find suitable places of existence and spread. 相似文献
13.
Burša Milan Raděj Karel Šima Zdislav True Scott A. Vatrt Viliam 《Studia Geophysica et Geodaetica》1997,41(3):203-216
The geopotential scale factor R
o
= GM/W
o
(the GM geocentric gravitational constant adopted) and/or geoidal potential Wo have been determined on the basis of the first year's (Oct 92 – Dec 93) ERS-1/TOPEX/POSEIDON altimeter data and of the POCM 4B sea surface topography model: R
o
°=(6 363 672.58°±0.05) m, W
o
°=(62 636 855.8°±0.05)m
2
s
–2
. The 2°–°3 cm uncertainty in the altimeter calibration limits the actual accuracy of the solution. Monitoring dW
o
/dt has been projected. 相似文献
14.
外来种福寿螺(Pomacea canaliculata)相较我国本土螺类其牧食量更大且繁殖速度更快,对栖息地水生植物的现存量和实施水生植被恢复的生态治理工程的成功性可能构成威胁,目前对福寿螺影响浅水湖泊沉水植物的重建缺乏足够的研究.本文通过设置不同沉水植物种类组合系统,研究福寿螺对3种常用于浅水富营养化湖泊治理的沉水植物密刺苦草(Vallisneria denseserrulata)、轮叶黑藻(Hydrilla verticillata)、穗花狐尾藻(Myriophyllum spicatum)的牧食偏好以及不同植物配置系统理化因子的响应变化,结果表明福寿螺对沉水植物植株附着偏好为密刺苦草轮叶黑藻穗花狐尾藻,而牧食破坏强度为轮叶黑藻穗花狐尾藻密刺苦草,轮叶黑藻最容易受到福寿螺牧食影响而快速消亡,穗花狐尾藻叶片也会被全部牧食仅剩下茎,而苦草存活受到的影响较小.福寿螺会导致轮叶黑藻+密刺苦草组合系统中总氮、氨氮、总磷、正磷酸盐浓度显著升高,而密刺苦草+穗花狐尾藻组合中总磷、正磷酸盐浓度显著升高,但是在轮叶黑藻+穗花狐尾藻组合中仅总氮浓度显著升高.研究表明福寿螺能够影响沉水植物间的竞争关系,但是3种沉水植物均不能阻止福寿螺的牧食;福寿螺牧食会显著降低沉水植物生物量,最终会影响草型清水态系统的稳定性. 相似文献
15.
Species differences in stomatal control of water loss at the canopy scale in a mature bottomland deciduous forest 总被引：2，自引：0，他引：2
In order to evaluate factors controlling transpiration of six common eastern deciduous species in North America, a model describing responses of canopy stomatal conductance (GS) to net radiation (RN), vapor pressure deficit (D) and relative extractable soil water (REW) was parameterized from sap flux data. Sap flux was measured in 24 mature trees consisting of the species Carya tomentosa, Quercus alba, Q. rubra, Fraxinus americana, Liriodendron tulipifera, and Liquidambar styraciflua in a bottomland oak-hickory forest in the Duke Forest, NC. Species differences in model coefficients were found during the 1997 growing season. All species showed a reduction in GS with increasing D. RN influenced GS in the overstory shade intolerant L. styraciflua to a larger extent than the other species measured. In addition, despite a severe drought during the study period, only L. tulipifera showed a decline in GS with decreasing REW. The primary effect of the drought for the other species appeared to be early autumn leaf senescence and abscission. As a result, despite the drought in this bottomland forest accustomed to ample water supply, maximum daily transpiration (1.6 mm) and growing season transpiration (264 mm) were similar to a nearby upland forest measured during a year of above average precipitation. These results may aid in assessing differences in water use and the ability of bottomland deciduous species to tolerate alterations in the frequency or amount of precipitation. Results also suggest little variation in water use among forests of similar composition and structure growing in different positions in the landscape and subjected to large interannual variation in water supply. 相似文献
16.
Nga Yu Ho Vincent Wai Tsun Li Wing Lin Poon Shuk Han Cheng 《Marine pollution bulletin》2008,57(6-12):425
kif7 is a member of the kinesin superfamily members which are molecular motor proteins that move along microtubules in a highly regulated manner through ATP hydrolysis. In this paper, we report on the cloning of the Oryzias melastigma kif7 (omkif7) using primers designed according to the Japanese medaka (Oryzias latipes) database. The cloned omkif7 has an open reading frame of 3762bp and is deduced to encode a polypeptide of 1254 amino acids that possesses the putative ATP-binding and microtubule-binding motifs in its motor domain at the N-terminal region. We characterized the cloned omkif7 by comparison with the zebrafish kif7. Both omkif7 and zebrafish kif7 are shown to be expressed in all embryonic stages and adult tissues examined with higher expression level in the testis and ovary. Whole-mount in situ hybridization revealed that the expression of omkif7 is ubiquitous during the early stages of embryonic development, but became more restrictive and localized to the brain, fin bud and eye at later development. This study suggested that the brackish O.melastigma can serve as a good seawater model organism for developmental studies by utilizing the resources developed from its close relative of the Japanese medaka. 相似文献
17.
An Aphanomyces sp. (Oomycetes) was found to be an important egg parasite of Eudiaptomus gracilis (Copepoda) in Lake Mondsee (Austria). The infection is evidenced by densely packed infection hyphae, attached with holdfasts and wrapped around the female's abdomen. The infection hyphae give rise to hyphae which penetrate the egg sac, and subsequently kill all eggs. The infection obviously has no pathogenetic effects on the egg-carrying female. Infected females appear during summer and fall, mainly in warm water layers. Infected egg clutches are found at all seasons of the year, indicating considerable birth control of the Eudiaptomus population by parasite infection. It seems possible that the actual Aphanomyces sp. is not the only parasite involved. 相似文献
18.
城市河道黑臭底泥对挺水植物光合荧光特性的影响 总被引：4，自引：1，他引：3
城市河道黑臭现象日益严重,探讨常见湿地植物在黑臭底泥中的生长,有利于为河道修复物种选择提供科学依据.研究黑臭底泥对3种常见湿地植物——菖蒲(Acorus calamus)、美人蕉(Canna indica)及慈姑(Sagittaria sagittifolia)生长状况和叶片叶绿素荧光参数的影响.结果表明:菖蒲和美人蕉在第30~40 d时生物量增量明显降低,慈姑的生物量增量在整个实验中持续增加;通过比较3种湿地植物的荧光参数可知,菖蒲和美人蕉的光化学淬灭系数(q P)、相对光合电子传递速率(r ETR)值在第10 d时达到最大,分别为41.33μmol/(m2·s)和68.60μmol/(m2·s),后30 d一直下降;慈姑q P、r ETR值在第30 d时增加;在第40 d时,美人蕉q P值下降,非光化学淬灭系数(q N)值上升,叶片有较强的热耗散能力,而菖蒲的q P、q N值同时下降,黑臭底泥对菖蒲叶片的光合系统PSⅡ造成伤害.这说明黑臭底泥对菖蒲和美人蕉的光合能力产生较长期抑制,而慈姑可较快适应黑臭底泥的胁迫.因此利用湿地植物修复黑臭河道时,可优先选择慈姑,其次是美人蕉,最后是菖蒲. 相似文献
19.
The effects of a mixture of heavy metals (Pb, Zn and Cu) on growth, radial oxygen loss (ROL) and the spatial pattern of ROL were investigated in mangrove seedlings of three species: Aegiceras corniculatum, Avicennia marina and Bruguiera gymnorrhiza. Heavy metals inhibited the growth of seedlings and led to decreased ROL and changes in the “tight” barrier spatial pattern of ROL. There was a significant positive correlation between the amount of ROL from the roots of seedlings and metal tolerance. The species with the highest ROL amount, B. gymnorrhiza, were also the most tolerant to heavy metals. The “tight” barrier spatial ROL pattern was also related to metal tolerance in the seedlings. Therefore, we conclude that both ROL amount and “tight” barrier spatial ROL pattern in the roots of the mangrove seedlings play an important role in resistance to heavy metal toxicity. 相似文献
20.
The present paper analyses predation patterns, of Percichthys trucha and salmonid fish upon Galaxias maculatus in five lakes of northern Patagonia with differing community and environmental characteristics. Tank experiments were performed to evaluate relative efficiency of native and exotic predators of G. maculatus under treatments with and without cover (aquatic vegetation). Important differences were found between predators with regards to distribution and consumption of G. maculatus. Salmonids are more efficient than P. trucha in consuming G. maculatus in deep environments with scarcely vegetation; in contrast to native species they frequently use the pelagic environment. Although pelagic habitat might have served in the past as a refuge from native predators in the past, G maculatus now experiences intense predation in the pelagic zone by exotic salmonids. It is suggested that the widespread distribution of G. maculatus in Patagonian lakes may have facilitated the success of salmonids throughout Patagonia. 相似文献