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1.
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:3,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   

2.
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   

3.
肖茜  杨昆  洪亮 《湖泊科学》2018,30(4):1083-1096
以云贵高原湖泊近30 a来的TM、ETM~+和OLI遥感影像为数据源,采用归一化水体指数(NDWI)、改进归一化水体指数(MNDWI)、新型水体指数(NWI)、增强型水体指数(EWI)和自动水体提取指数5种水体指数提取了1985—2015年云贵高原10个湖泊表面水体面积,并对各种算法进行精度对比分析.针对湖泊各自特点采用不同的水体指数提取其表面水体面积,并进行水体面积变化时空分析.结果表明:云贵高原湖泊表面水体面积总体呈现先增加后缩减趋势,1985—1995年湖泊表面水体面积增加了30.86 km~2,1995—2015年湖泊水体表面面积减少了48.12 km~2,其中,面积变化最大的是杞麓湖与异龙湖.对云贵高原湖泊表面水体面积变化与该区域的年降水量、蒸发量、平均气温、流域植被覆盖面积和人类活动时空进行相关分析,结果表明:1)高原湖泊对区域气候变化的响应具有明显的空间差异性,云贵高原湖泊的表面水体面积与气候相关性较显著,气温升高引起蒸发加速,降水量下降,湖面不断缩小,与逐年上升的气温呈负相关,与逐年波动上升的蒸发量呈负相关,与逐年减少的降水量呈正相关;2)云贵高原湖泊各流域的植被覆盖面积与湖泊面积变化相关性较弱;3)人类活动是影响湖泊面积变化的重要因素,大肆围湖造田、围湖养殖以及旅游开发等人类活动直接导致云贵高原湖泊面积的锐减,并对湖泊生态环境产生重要影响.  相似文献   

4.
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   

5.
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   

6.
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   

7.
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   

8.
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   

9.
通过野外调查并结合历史数据对洪湖沉水植被进行长时间序列变化研究,构建自1950s以来洪湖主要优势沉水植物群落穗状狐尾藻(Myriophyllum spicatum)、微齿眼子菜(Potamogeton maackianus)、金鱼藻(Ceratophyllum demersum)和轮叶黑藻(Hydrilla verticillata)的群落分布图并计算其面积.结果表明:穗状狐尾藻群落面积从1950s占全湖的6%增加至1990s的65%,而后急剧下降至2010年的2%,然后又恢复至2014年的15%;微齿眼子菜群落面积从1950s的10%增至1990s的65%,然后下降至2014年的38%;金鱼藻群落面积从1980s的6%增至1990s的39%,2010年以后则稳定在25%;轮叶黑藻群落面积1950s占全湖的32%,随后急剧下降至1980s的6%,2000年以后逐步增加,至2014年为15%.1950s1990s,穗状狐尾藻、微齿眼子菜和金鱼藻群落分布范围从周边向湖心扩展,而轮叶黑藻群落从湖中心消失;2000年以后洪湖沉水植物群落分布破碎化明显.分析认为,1950s 1990s的围垦和水文过程变化,1990s 2005年的围网养殖、水生植物过度利用以及由此导致的水质恶化等,以及2006年至今开展的拆围和生态修复是导致这些变化的主要因素.建议取缔围网,控制入湖水质,提高水体透明度,促进水生植被恢复,但同时增加水位变幅,促进植物资源合理利用,避免沼泽化重演.  相似文献   

10.
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   

11.
12.
长江流域是我国刀鲚(Coilia nasus)分布的重要水域传统意义上认为,刀鲚存在长颌鲚和短颌鲚2种表现型,其上颌骨的长或短是区分刀鲚溯河洄游、淡水陆封(湖鲚)和淡水定居3种生态型的关键外形指标然而这种主观分型经验尚需要野外调查数据验证本研究基于以往研究所获溯河洄游和淡水栖息刀鲚不同的耳石微化学图谱技术,首先对采集自长江中下游及附属湖泊的刀鲚群体共566尾个体有无溯河洄游"履历"进行了分析确认;再对其上颌骨长、头长、全长进行方差分析和回归分析结果发现长颌鲚、短颌鲚在早期发育阶段,长、短颌特征分化并不明显当发育至幼鱼阶段时,前者上颌骨长会长于头长;而后者全生活史过程中上颌骨长均短于头长发育至幼鱼阶段可能是刀鲚长、短颌鲚分型的临界生活史阶段此外,长颌鲚中同时存在溯河洄游和淡水定居两种生态型个体,其上颌骨长/头长比值(S/H)分别为1.170±0.075和1.165±0.064,两者S/H比值与形态上同为长颌的湖鲚比值(1.178±0.087)无显著性差异短颌鲚亦同时存在溯河洄游和淡水定居两种生态型个体,两者的S/H比值分别为0.922和0.918±0.062,与上述3类长颌鲚的S/H比值均差异极显著因此,建议把长江干流及太湖、鄱阳湖、洞庭湖等水域内3种传统生态型的刀鲚细分为溯河洄游型、淡水定居型长颌鲚,溯河洄游型、淡水定居型短颌鲚以及陆封型湖鲚5种生态表型.  相似文献   

13.
不同藻类对温度与磷叠加作用的响应模式   总被引:1,自引:1,他引:0  
气候变暖对富营养化引起的蓝藻水华扩张具有叠加作用,为探索不同藻类对气候变暖与富营养化叠加作用的响应模式,选用富营养化水体常见藻类铜绿微囊藻(Microcystis aeruginosa)、水华鱼腥藻(Anabaena flos-aquae)和斜生栅藻(Scenedesmus obliquus)作为材料,采用室内培养方法,模拟春末不同升温幅度(20+3、23+3和20+6℃),5个磷浓度水平(0、0.05、0.15、0.30和0.50 mg/L),通过生长速率、光化学参数等的测定,分析不同藻类对温度升高和营养盐添加的生长与光化学响应.结果表明:3种藻的生长速率对温度和磷的叠加作用呈现不同的响应模式:随着磷浓度的升高,铜绿微囊藻的生长速率受温度的叠加作用不断增加,26℃时差异最大;水华鱼腥藻生长速率除在0.30 mg/L磷浓度时受温度叠加作用比较明显外,其他磷浓度水平均没有显著的叠加效应;斜生栅藻在不同磷浓度水平下受温度叠加作用影响有较大波动,但无明显差异.铜绿微囊藻对温度的叠加作用随着磷浓度的增加呈现逻辑斯蒂模式增长,而水华鱼腥藻和斜生栅藻均是在特定温度或特定营养盐浓度时呈现最大的叠加作用,叠加作用的趋势不明显.从Fv/Fm结果可知,铜绿微囊藻下降幅度明显高于水华鱼腥藻和斜生栅藻,随温度升高,磷浓度越高,铜绿微囊藻的Fv/Fm下降幅度越大,这可能是铜绿微囊藻在高生长速率下色素无法积累所致;水华鱼腥藻的Fv/Fm基本保持稳定,各组间差异较小;斜生栅藻的Fv/Fm在低磷浓度组明显低于高磷浓度组,并且随温度升高下降趋势增加,3种藻的光学特性响应反映了藻类在叠加作用下生长的变化.综上所述,铜绿微囊藻对温度上升与磷浓度的升高有更强的响应,导致其产生更高的生长速率,从而促进了蓝藻水华的扩张.  相似文献   

14.
We compared three methods for calculating the standing stock biomass ofDaphnia hyalina galeata population in Lago Maggiore during a single year. We applied body length/carbon regression equations (LCR) obtained under controlled laboratory conditions and directly from field data on carbon and body length to field data on length-specific abundance. Laboratory-derived equations satisfactorily described our field estimates of length-specific carbon content in spring. As the length-standardized carbon content decreased exponentially along the season, we included time of the year as an auxiliary variable, and tested whether it affected slope, intercept or both. The decrease had no effect on slope but reduced the intercept of the LCR. We also calculated biomass, using a single mean value from the literature. By comparing the results with those obtained by simple conversion of individuals number into carbon we might discriminate between the effect of changes in the size frequency distribution of the population and the decrease with time of the length-standardized carbon content. Although we tested the different models for non-ovigerous females, the results did not change when we included also data on females with eggs in the first three developmental stages, whereas they changed substantially when we included females with embryos. We formulate two hypotheses to explain this result and discuss possible implications for the calculation of the standing stock biomass ofDaphnia population.  相似文献   

15.
The influence of parasites on the breeding biology of the European minnow (Phoxinus phoxinus) was studied by examining 268 adult and 59 young-of-the-year minnows from an artificial Swiss Alpine lake for parasites during the breeding seasons in 1990 and 1991. Two trematode parasites;Diplostomum phoxini, in their brains, andMacrolecithus papilliger, in their guts, were found. The prevalence ofD. phoxini was 100% in both years. The mean abundance was 231 in 1990 and 448 in 1991; the difference was significant. Prevalence (and abundance) ofM. papilliger was 37.5% (1.04±0.39) in 1990 and 59.5% (2.68±0.55) in 1991; also significantly higher in 1991 than in 1990. No differences in prevalence or abundance between males and females were found. Numbers of both parasites were significantly correlated with fish length. There was seasonal variation in the abundance ofD. phoxini metacercariae, with a peak in June/July in both years. The prevalence ofM. papiller decreased after July in both years. Distribution of the two trematodes was overdispersed as indicated by the variance to mean (abundance) ratio. The observed seasonal variation inD. phoxini abundance also suggests that sublethal parasites could influence the population dynamics of their hosts.  相似文献   

16.
放养河蚌,提高水体透明度以促进沉水植物生长,是湖泊生态修复中的常用手段之一.而小型杂食性鱼类鳑鲏依赖河蚌繁殖,河蚌放养可能会促进鳑鲏种群的发展;而鳑鲏与河蚌交互作用对水生态系统的影响仍研究较少.于2018年11-12月通过原位受控实验,设置对照组、河蚌组、鳑鲏组和河蚌+鳑鲏组,研究了鳑鲏(大鳍鱊Acheilognath...  相似文献   

17.
温度波动对浮游藻类生长及多糖组成的影响   总被引:4,自引:1,他引:3  
覃宝利  杨州  张民 《湖泊科学》2014,26(3):432-440
以铜绿微囊藻、蛋白核小球藻及梅尼小环藻为研究对象,分析了春季藻类演替期间主要门类藻对温度波动的响应,实验在恒温(20℃)和昼夜波动(20±5℃)2种温度模式下测定了3种藻的生长和不同形态多糖含量的变化.结果表明,蛋白核小球藻的生长曲线在不同处理条件下没有显著性差异,铜绿微囊藻和梅尼小环藻的生长曲线在波动温度组显著低于恒定温度组,而且温度波动对梅尼小环藻的生长抑制明显强于铜绿微囊藻.随着实验的进行,3种藻在2个温度处理组中的生长速率逐渐趋近,无显著差异,但是在实验中段3种藻的生长速率对2个温度处理的响应差异显著,其中温度波动对蛋白核小球藻的生长速率起到了显著的抑制作用,对梅尼小环藻起到短暂的显著抑制作用,而对铜绿微囊藻的生长速率无显著性影响,表明铜绿微囊藻对短期(3~6 d)的温度波动表现出较强的适应能力.铜绿微囊藻的游离多糖含量在温度波动条件下显著增加,而固着多糖和总多糖的含量显著减少;蛋白核小球藻和梅尼小环藻多糖的含量没有显著性变化,表明温度波动可能不利于铜绿微囊藻固着多糖的积累.因此,相对短期的温度波动有利于铜绿微囊藻生长优势的确立与维持,而相对长期的温度波动可能会通过影响铜绿微囊藻固着多糖的积累而影响其生长优势的维持.  相似文献   

18.
由于严重的水体富营养化,太湖长期暴发蓝藻水华,这些蓝藻在代谢及消亡过程中大量释放包括腐植酸在内的有机物,不仅影响供水水质,并且进一步加重了水华程度.以太湖水华优势藻种——水华微囊藻(Microcystis flos-aquae T34)为研究对象,对藻株生长周期中的藻细胞、浮游细菌进行计数,并使用TOC仪与三维荧光光谱对培养液中提取的腐殖酸进行定量与定性分析,探究水华微囊藻在生长过程中藻细胞密度、浮游细菌密度与腐殖酸浓度的变化规律.结果表明,培养液中腐殖酸浓度的变化趋势与细菌数量变化趋势一致,但与细菌数量曲线拐点相比,腐殖酸浓度曲线拐点出现两周的延迟.腐殖酸产量在藻细胞对数期较低,当水华微囊藻进入稳定期与衰亡期后,腐殖酸大量产生,其浓度迅速增加,最高可达到28.6 mg/L.根据三维荧光光谱分析,水华微囊藻所产生的腐殖酸特征峰出现在(235~245 nm)/(380~425 nm),属于类富里酸荧光峰.本研究初步探究蓝藻与水体腐殖酸之间的关系,为水体腐殖酸来源的研究提供了新的思路.  相似文献   

19.
沉水植物在湖泊生态系统中具有重要作用,它不仅是湖泊生态系统食物链中重要的生产者,同时还对湖泊的营养物沉积和循环有着重要的意义,并由此影响着湖泊的富营养化进程.本文以黄河内蒙古段河套灌区湖泊中常见的3种沉水植物篦齿眼子菜(Potamogeton pectinatus)、穿叶眼子菜(Potamogeton perfoliatus)和狐尾藻(Myriophyllum verticillatum)为研究对象,对其种子休眠及萌发特性进行了初步研究.结果表明:狐尾藻种子休眠率较高但休眠易破除,通过切破种皮、低温层积、硝酸钾和赤霉素处理均可显著提高萌发率;篦齿眼子菜种子休眠性较强,低温层积及赤霉素浸泡处理能够显著提高其萌发率;穿叶眼子菜有较深的休眠特性,破除硬实、硝酸钾、赤霉素及低温层积处理均不能有效解除其休眠.  相似文献   

20.
拟柱孢藻(Cylindrospermopsis raciborskii)和角星鼓藻(Staurastrum spp.)是热带亚热带浮游植物群落中的常见优势种类,为了解铁对2种浮游植物季节动态和生长的影响,本文通过对典型热带水库的野外调查,分析铁与2种藻生物量和相对生物量的季节动态的关系,并通过室内实验分别以无机磷(KH2PO4)和有机磷(C6H13O9P)为磷源,比较3种铁浓度(0.029、0.29和0.689 mg/L)下拟柱孢藻(C.raciborskii,N8)和角星鼓藻(Staurastrum sp.,FACHB-1449)的比生长速率、铁载体产量和碱性磷酸酶活性的差异.结果显示,拟柱孢藻和角星鼓藻是浮游植物群落的主要优势种类,两者的生物量最大占到总生物量的82%以上;两者对环境变量响应的区别主要体现在对溶解性铁浓度变化的响应差异上,拟柱孢藻生物量与溶解性铁有显著的线性回归关系,但角星鼓藻的生物量与铁没有显著线性回归关系.室内实验中,拟柱孢藻N8的比生长速率在无机磷源铁浓度为0.689 mg/L条件下最大,为0.098±0.01 d-1,2种磷源条件下比生长速率均随铁浓度降低而显著降低,6个实验组均检到铁载体:6个实验组角星鼓藻FACHB-1449的比生长速率没有明显差异,平均为0.079±0.001 d-1,均未检出铁载体,磷源和铁浓度对其比生长速率的影响不显著;有机磷源条件下,拟柱孢藻N8实验组碱性磷酸酶活性均显著高于角星鼓藻FACHB-1449实验组,拟柱孢藻N8实验组酶活性随铁浓度降低而显著降低,但角星鼓藻FACHB-1449各实验组的碱性磷酸酶活性无明显差异.以上结果表明,水体中溶解性铁的供应对拟柱孢藻的种群动态和优势有重要作用,与角星鼓藻相比,拟柱孢藻的生长更易受到铁的限制,尤其在无机磷缺乏、磷源主要以有机磷形式供应时,铁对拟柱孢藻生长的限制作用增强.  相似文献   

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