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1.
Nylon bags containing yellow leaves of Rhizophora apiculata and Avicennia marina, were immersed for 80 days from August to October, 1996. the decomposing leaves were collected every 10 days and analysed for dry weight loss and six biochemical parameters: tannins, total amino acids, total sugars, total nitrogen, total lipids and fatty acid profile. the leaf weight initially decreased very rapidly by about 50% of the start in two species of mangroves within 10 days. Similar changes were observed with tannins, total amino acids and sugars. However, the concentration of nitrogen increased significantly with decomposition. There was no significant change in total lipid and fatty acid profile. the highest concentration of fatty acid in the decomposing leaves was palmitic acid (16:0). Unsaturated fatty acids such as, 18:1 w7c and 18:1 w9c were found to be present in decomposing leaves of both species. 相似文献
2.
运用完全分解模型详细研究了2000-2007年间滨海新区能源消费总量变化的过程。结果表明,2000-2007年期间,经济规模扩张因素所产生的增长效应对滨海新区能源消费总量的持续增长起主导作用。与此同时,产业结构的变动对能源消费的减量作用为负面的,技术进步因素产生的能源强度效应则是推动滨海新区能源消费减量的主要因素。笔者认为,推动产业结构的跨越式演进以及在未来城市规划中增加能源消费总量约束性的发展指标是滨海新区实现能源消费总量降低的重要途径和手段。 相似文献
3.
根据定位系统观测资料,阐述了南亚热带山地常绿森林区、丘陵旱作区和平原水稻区多种土壤的温度变化与气温的关系。观测研究结果表明:低山常绿森林区温度的三维空间差异比丘陵区、平原区大,丘陵区又比平原区大;南亚热带林区的气温、地表温、30cm土温比中亚热带的高,比热带的低:南亚热带林区的谷地气温高于针叶林、混交林和阔叶林,谷地地表温低于针叶林而高于混交林和阔叶林,谷地20m土温低于针叶林、混交林而高于阔叶林;在气温一致的丘陵区栽植植物不同,其地表温、土温略有差异;在平原水稻土区,年气温、地表温、20cm土温差异不大,但30cm以下土温渐显差异;不同地貌单元的气温、地表温和土温的年际差异、年平均温度、各月及0~12~24时的温度动态变化各具特征。根据气温与植物生长的关系,拟把气温>22℃的4~10月称热季、气温<22℃的1~3月及11~12月称作凉季。可因地制宜,根据气温和土温的变化特征与土壤水分和作物生长的关系,采取措施调节温度,以利于作物生长。 相似文献
4.
The decomposition of leaf litter is controlled by several factors. One factor that may play an important role is the content
of condensed tannins (proanthocyanidins). Here we designed a combined method to isolate proanthocyanidins from leaf extracts,
to convert them to anthocyanidins, and to quantify individual anthocyanidins exactly with a new, simple, but sensitive high-performance
liquid chromatography method. We used this method to show composition of proanthocyanidins and to monitor degradation of proanthocyanidins
and individual constituents in leaf litter in an aquatic environment over time. Despite the rapid decrease in the initial
concentrations, a fraction of the proanthocyanidins remained detectable for several weeks. 相似文献
5.
亚热带小区域水平上土壤质量时空变化的定量化评价 总被引:4,自引:0,他引:4
亚热带小区域水平上土壤质量时空变化的定量化评价王效举,龚子同(中国科学院南京土壤研究所,南京210008)QuantitativeEvaluationofSoilQualityChangesinTimeandSpaceataSmallAreaLeve... 相似文献
6.
The variations of the biochemical composition of Tetraselmis suecica and Isochrysis galbana during growth and decay were determined. the content of chlorophyll a (Chl-a) of the cultures, as expected, slowly degraded into phaeopigments during decay, confirming that chlorophyll measurements do not always provide an accurate estimate of phytoplanktonic biomass and, consequently, may fail if used to measure the food availability of particulate matter for consumers. Measurements of total amounts of proteins, carbohydrates and lipids, related to the nutritional value of particles in terms of caloric content, are shown to provide information on the readily available food for consumers, particularly during the blooms. the protein/carbohydrate, C/N and POC/Chl-a ratios were used to evaluate the differences between these two species during the growth and the decomposition processes. A comparison between experimental and field conditions was undertaken to implement our understanding of the growth and degradation processes of particulate organic matter of phytoplanktonic origin in the sea and its role on natural systems, during and after phytoplankton blooms. 相似文献
7.
铁浓度诱导的三角褐指藻生长和生化组分变化 总被引:1,自引:1,他引:1
采用试验生态学方法,以海洋硅藻三角褐指藻(Phaeodactylum tricornutum)为研究材料,设置一系列铁浓度处理(3.15mg·L-1、6.30 mg·L-1、9.45 mg·L-1、18.90 mg·L-1和34.65 mg·L-1),着重测定藻液光密度(OD450)、比生长率、藻细胞密度、藻生物量、叶绿素含量和蛋白质含量等生理生化指标,探讨铁浓度对海洋微藻生长特性和生化组分的影响.结果表明,铁浓度对三角褐指藻的生长状况产生了显著的影响.三角褐指藻经培养48 h后,不同铁浓度下的藻液光密度(OD450)存在显著的差异,6.30 mg·L-1铁浓度下的藻液光密度值(OD450)最高,而随着铁浓度的进一步升高,藻液光密度值(OD450)却明显降低;比生长率和藻细胞密度在3.15 mg·L-1到9.45 mg·L-1铁浓度范围内随着铁浓度升高而增大(最大值分别约为0.609 d-1和1200×104 cell·mL-1),但高于9.45 mg·L-1的铁浓度显著降低了比生长率和藻细胞密度;在试验所设置的铁浓度范围内,藻生物最表现出随铁浓度的升高而增大的趋势,34.65 mg·L-1铁浓度下的藻生物量高达0.460 mg·ML-1.同样地,微藻叶绿素a含量和蛋白质含量也明显地受到铁浓度的影响.在3.15 mg·L-1到18.90 mg·L-1铁浓度范围内,叶绿素a含量逐渐增高(最大值为2.41 mg·L-1);同样地,蛋白质含量在9.45 mg·L-1.铁浓度下达到最大值(0.153 mg·mL-1),而随着铁浓度的逐渐升高,叶绿素和蛋白质含量却明显降低.研究结果表明.铁浓度诱导海洋微藻的生长及代谢发生变化.一定较高浓度的铁显著地促进了藻细胞的生长繁殖和藻细胞化学组分的转化和积累.这些发现将有利于加深认识铁浓度在海洋生态系统中扮演的角色,进一步明确赤潮爆发的生理生态机制,从而有助于人们采取有效的预测、预防和管理措施以降低赤潮的危害. 相似文献
8.
能源足迹变化的多因素影响效应研究——以吉林省为例 总被引:2,自引:0,他引:2
采用对数平均迪氏指数法构建能源足迹因素分解模型,定量分析1994—2008年吉林省能源足迹变化的主要影响因素及其效应特征。结果表明,1994—2008年,吉林省人均能源足迹从0.228 hm2增至0.524 hm2。在能源足迹增长的抑制因素中,能源强度效应占84.54%,排放因子效应占15.46%;在能源足迹增长的促进因素中,经济产出效应占91.39%,能源结构效应占4.30%,人口规模效应占3.73%,土地固碳效应占0.57%。以经济产出因素为主导的正效应明显大于以能源强度因素为主导的负效应,两者之比为1.73∶1,叠加表现为对能源足迹增长的促进作用,导致其总体呈递增趋势。此外,在正、负效应的双变量格局下,能源足迹呈复合曲面分布。目前减缓吉林省能源足迹增长的重点在于通过技术进步促进能源强度下降,同时需调整能源结构以发挥其应有的抑制作用。 相似文献
9.
PAOLO GUIDETTI 《Conservation biology》2007,21(2):540-545
Abstract: Fishing and other human activities can alter the abundances, size structure, and behavior of species playing key roles in shaping marine communities (e.g., keystone predators), which may in turn cause ecosystem shifts. Despite extensive evidence that cascading trophic interactions can underlie community-wide recovery inside no-take marine reserves by protecting high-level predators, the spatial extent of these effects into adjacent fished areas is unknown. I examined the potential for community-wide changes (i.e., the transition from overgrazed coralline barrens to macroalgal beds) in temperate rocky reefs within and around a no-take marine reserve. For this purpose I assessed distribution patterns of predatory fishes, sea urchins, and barrens across the reserve boundaries. Predatory fishes were significantly more abundant within the reserve than in adjacent locations, with moderate spillover across the reserve edges. In contrast, community-wide changes of benthic assemblages were apparent well beyond the reserve boundaries, which is consistent with temporary movements of predatory fishes (e.g., foraging migration) from the reserve to surrounding areas. My results suggest that no-take marine reserves can promote community-wide changes beyond their boundaries. 相似文献
10.
Lara Rubén Szlafsztein Claudio Cohen Marcelo Berger Uta Glaser Marion 《Journal of Coastal Conservation》2002,8(1):97-102
This work analyses effects of recent variations in the tidal inundation frequency in a mangrove ecosystem in the Bragança peninsula, North Brazil, and its implications for land occupation and use. Field data, time series of remote sensing images and local legislation were analysed focusing on the potential socio-economic impact of a changing environmental setting due to a rise in relative sea level. In the investigated period (1972–1997), vegetation changes along the coastline indicate net losses of mangrove coverage. In the central part of the peninsula, a topographically higher herbaceous plain constituting part of a farm presents an active progression of mangrove forest into an area previously dominated by grasses and herbs. This area measured 8.8 km2 in 1972 but was gradually reduced to 5.6 km2 in 1997, while progressively replaced by a monospecific stand of the black mangrove,Avicennia germinans. A linear extrapolation indicates that the elevated plain may be completely covered by mangrove by 2035. Current Brazilian legislation prohibits the extraction of mangrove trees without an officially approved management plan. Thus, the usable area of the farm has suffered a reduction by ca. 36% over 25 yr and we predict that is could be entirely replaced by mangroves in the next 35 yr. In this case study, legislation and ecosystem characteristics are analysed and a management plan discussed which could represent income alternatives for affected resource users at the local and regional level. 相似文献
11.
水位是影响滨海湿地生态系统蓝碳功能的重要因素。气候变化引起的海平面上升以及极端气候事件的频发,可能加快水位的变化,从而改变生态系统碳交换的过程。然而,滨海湿地碳汇功能响应水位变化的机制尚不清楚。为了评估水位对滨海湿地净生态系统CO2交换(NEE)特征的影响,以及验证DNDC(denitrification-decomposition)模型对模拟预测滨海湿地生态系统碳交换的适用性,该研究设计了野外水位控制试验(自然水位,地下20 cm水位、地表10 cm水位),并利用DNDC模型模拟和预测水位变化对滨海湿地NEE的影响。结果表明:(1)不同水位处理之间NEE差异显著,地表10 cm水位处理促进CO2吸收,地下20 cm水位则抑制CO2吸收;(2)经过校准和验证的DNDC模型可以准确模拟水位变化对黄河三角洲湿地NEE的影响,NEE模拟值的日动态与田间观测结果显著相关(R2>0.6);(3)通过改变气候、土壤和田间管理等输入参数对DNDC模型进行灵敏度检验,生态系统碳交换过程对日均温、降雨和水位改变的响应最为显著,其中,水位对NEE的影响主要作用于土壤呼吸(Rs)。未来气候情境下,不同水位变化下的生态系统碳交换过程随年份增长呈现不同的规律,因此未来的模拟研究应关注DNDC中水文模块和植被演替过程的完善。该研究可为预测水文变化情境下滨海湿地碳汇功能的未来发展以及政策制定提供参考。 相似文献
12.
Shinya Hosokawa 《Ecological modelling》2011,222(1):105-111
A new model for determining leaf growth in vegetative shoots of the seagrass Zostera marina (eelgrass) is described. This model requires the weights of individual mature and immature whole leaves and leaf plastochrone interval (PL) as parameters, differing from the conventional leaf marking technique (CLM) that requires cutting and separation between new and old tissue of leaves. The techniques required for the model are the same as for the plastochrone method, but the parameters differ between both methods in use of the weight of individual immature leaves. In a mesocosm study, eelgrass growth was examined, and parameters for the new model and plastochrone method (the weights of individual mature and immature leaves and PL) were measured. Leaf growth rate was measured using the CLM and determined by the new method and the plastochrone method. The results were then compared between the CLM, the new model, and the plastochrone method. The results obtained with the new model were similar to those obtained with the CLM. However, the results of the plastochrone method differed from those of the CLM, while the weight of immature leaves varied seasonally. The new model was also used to determine leaf growth in a natural eelgrass bed in Mikawa Bay, Japan, and revealed the growth rates in all shoots and those of different ages. This method would be advantageous as an accurate means of direct measurement in fieldwork, and should therefore be a useful tool for monitoring seagrass growth. 相似文献
13.
Leila T. Hatch Christopher W. Clark Sofie M. Van Parijs Adam S. Frankel Dimitri W. Ponirakis 《Conservation biology》2012,26(6):983-994
The effects of chronic exposure to increasing levels of human‐induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human‐induced sound on contact‐calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (~10,000 km2) and time period (peak feeding time). We used an array of temporary, bottom‐mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel‐tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal‐to‐noise ratio and the assumed recognition differential) for contact‐calling right whales was negative (?1 dB) under current ambient noise levels and was further reduced (?2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10‐min period. These results highlight the limitations of exposure‐threshold (i.e., dose‐response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide‐ranging noise effects in emerging ocean‐planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A. 相似文献
14.
Carlos Palacín Juan C. Alonso Carlos A. Martín Javier A. Alonso 《Conservation biology》2017,31(1):106-115
Many bird populations have recently changed their migratory behavior in response to alterations of the environment. We collected data over 16 years on male Great Bustards (Otis tarda), a species showing a partial migratory pattern (sedentary and migratory birds coexisting in the same breeding groups). We conducted population counts and radio tracked 180 individuals to examine differences in survival rates between migratory and sedentary individuals and evaluate possible effects of these differences on the migratory pattern of the population. Overall, 65% of individuals migrated and 35% did not. The average distance between breeding and postbreeding areas of migrant individuals was 89.9 km, and the longest average movement of sedentary males was 3.8 km. Breeding group and migration distance had no effect on survival. However, mortality of migrants was 2.4 to 3.5 times higher than mortality of sedentary birds. For marked males, collision with power lines was the main cause of death from unnatural causes (37.6% of all deaths), and migratory birds died in collisions with power lines more frequently than sedentary birds (21.3% vs 6.3%). The percentage of sedentary individuals increased from 17% in 1997 to 45% in 2012. These results were consistent with data collected from radio‐tracked individuals: The proportion of migratory individuals decreased from 86% in 1997–1999 to 44% in 2006–2010. The observed decrease in the migratory tendency was not related to climatic changes (temperatures did not change over the study period) or improvements in habitat quality (dry cereal farmland area decreased in the main study area). Our findings suggest that human‐induced mortality during migration may be an important factor shaping the migration patterns of species inhabiting humanized landscapes. 相似文献
15.
茶园土壤的有机质含量、腐殖质组成、有机碳的循环与平衡特点、酶活性及其在施肥条件下的变化情况与土壤肥力密切相关.试验结果表明:亚热带茶园土壤有机质含量水平较低,腐殖质组成中以富里酸为主,HA/FA比、酶活性均比起源土壤略低;高产茶园土壤有机碳库的循环水平较高,在不施有机肥的情况下仍能保持平衡;低产茶园土壤有机碳库的循环水平较低,输出大于输入,施用有机肥可以较快地提高茶园土壤有机质含量和酶活性水平.增施有机肥和实行茶林复合是培肥茶园土壤、提高茶园生产力的有效措施. 相似文献
16.
盐胁迫条件下三角滨藜叶片中盐分的积累与分配 总被引:9,自引:0,他引:9
用扫描电镜和能谱仪测定不同浓度NaCl胁迫2wk后的三角滨藜幼叶和成熟叶中Na 在细胞外和细胞内的分布情况,并利用原子吸收分光光度计测定叶片中Na 的积累量,同时还观测了盐囊泡及其与盐的积累、分泌之间的关系.结果表明,在盐胁迫下,三角滨藜叶片中的Na 积累量随根外溶液盐浓度的升高而增加,而盐囊泡的含盐量并无显著变化.同时发现,叶片中的Na 主要积累在细胞内.因此,可以认为,三角滨藜主要靠吸收并在细胞内积累Na 来降低渗透势,保证植株的水分吸收,而三角滨藜的盐囊泡在盐分分泌与抗盐中并无实质性作用.图2表3参12 相似文献
17.
基于遥感技术的松辽平原盐渍化动态研究 总被引:3,自引:0,他引:3
运用.RS、GIS手段,以航天遥感MSS/TM/ETM为主要信息源,运用参数构造法、空间叠加分析法和网格等值线追踪法.对松辽平原盐渍化进行多时相遥感动态监测.研究结果表明.近30年来松辽平原盐渍化面积持续增加.强度持续增强.盐渍化面积变化总动态度为-1.03%,其中,1975-1989年为-1.67%,1989-2003年为-0.31%.盐渍化强度中心位于大安与乾安之间,1975-1989年,强度中心向北东方向移动22.81 km;1989-2003年,强度中心向西南方向移动16.50 km.松辽平原盐渍化是自然因素和不合理人类活动共同作用造成的. 相似文献
18.
以神农架林区木鱼镇茶山上生长的8种不同类型植物为试验材料,于晴天选择其植株上东南朝向的顶部成长叶,采用LI-COR6400便携式光合测定系统、调制叶绿素荧光成像系统(IMAGING-PAM M-Series)及双通道PAM-100测量系统(Dual-PAM-100)和常规方法研究了其叶片特征、光合性能及相互间的关系,将有助于了解神农架植物的光合生产力及其植被管理。结果表明,不同类型植物叶片的叶片特征和光合性能存在明显的物种差异。比叶重(SLW)为乔木灌木草本;气孔参数以气孔导度(Cond)差异最大;草本植物的光合能力明显高于灌木和乔木,而灌木和乔木间的差异不大;叶绿素含量(Chl)及其组分的差异较小,类胡萝卜素(Car)和花青素含量(Ant)及其与Chl的比值差异极大。不同类型植物叶片特征和光合性能指标的变异系数在7.3%~73.0%间,Chla/Chlb最小,Car/Ant最大;Chla/Chlb、基于叶温的蒸汽压亏缺(VpdL)和胞间CO2浓度(Ci)小于15%,Cond、单位鲜重Car、PSII实际量子产量和PSI非光化学能量耗散的量子产量为40%~50%,单位干重Car、Ant、Chl/Ant和Car/Ant则大于60%,其他指标在20%~40%。相关分析显示,Pn受Cond、叶片含水量和单位干重Chl的正向调控,Ant和Car对Pn无决定性作用;PSII和PSI的实际量子产量依赖于Ci和Chl,Car过高导致其降低;PSI的光保护受SLW的负调控及单位鲜重Chl和单位干重Car的正调控;光合机构的光损伤受Ci的负调控和Chl/Car的正调控。 相似文献
19.
以神农架林区木鱼镇茶山上生长的8种不同类型植物为试验材料,于晴天选择其植株上东南朝向的顶部成长叶,采用LI—COR6400便携式光合测定系统、调制叶绿素荧光成像系统(IMAGING-PAMM-Series)及双通道PAM—100测量系统(Dual-PAM-100)和常规方法研究了其叶片特征、光合性能及相互间的关系,将有助于了解神农架植物的光合生产力及其植被管理。结果表明,不同类型植物叶片的叶片特征和光合性能存在明显的物种差异。比叶重(SLW)为乔木〉灌木〉草本;气孔参数以气孔导度(Cond)差异最大;草本植物的光合能力明显高于灌木和乔木,而灌木和乔木间的差异不大;叶绿素含量(Chl)及其组分的差异较小,类胡萝卜素(Car)和花青素含量(Ant)及其与Chl的比值差异极大。不同类型植物叶片特征和光合性能指标的变异系数在7.3%~73.0%间,Chla/Chlb最小,Car/Ant最大;Chla/Chlb、基于叶温的蒸汽压亏缺(VpdL)和胞间C02浓度(Ci)dx于15%,Cond、单位鲜重Car、PSII实际量子产量和PsI非光化学能量耗散的量子产量为40%~50%,单位干重Car、Ant、Chl/Ant和Car/Ant则大于60%,其他指标在20%-40%。相关分析显示,Jpn受Cond、叶片含水量和单位干重Chl的正向调控,Ant和Car对两无决定性作用;PSII和PSI的实际量子产量依赖于ci和Chl,Car过高导致其降低;PSI的光保护受SLW的负调控及单位鲜重Chl和单位干重Car的正调控;光合机构的光损伤受Ci的负调控和Chl/Car的正调控。 相似文献
20.
广州市区植物叶片重金属元素含量及其大气污染评价 总被引:39,自引:0,他引:39
文章通过对广州市区植物叶片中重金属元素含量的分析,研究了植物大气环境污染指数,探讨了植物叶片重金属元素含量与城市大气环境污染之间的关系。结果表明,植物叶片中Cu,Pb,Cd,Cr元素污染都较严重,在重污染区这些元素的含量明显高于清洁对照区;用植物污染指数可以综合评价大气环境质量状况;利用植物叶片内的重金属含量变化,为大气污染生物监测和环境质量评价提供了科学依据。 相似文献