2001-2008年我国湿地公园研究的文献学分析   总被引：3，自引：2，他引：1  

吴后建  但新球  王隆富  舒勇 《湿地科学与管理》2009,5(4):40-43

通过对2001-2008年我国国内出版发行的有关湿地公园的著作、学位论文和期刊论文的统计分析,揭示我国湿地公园研究的主题和内容、研究者的分布地区、部门分布状况,确定我国湿地公园研究的合作度、合著率、核心作者和活跃作者群,并确定我国湿地公园研究的热点区域,希望为我国湿地公园研究者和建设者了解和把握中国湿地公园研究现状和发展趋势提供依据。  相似文献   

Benthic recovery during open sea fish farming abatement in Western Mediterranean, Spain   总被引：1，自引：0，他引：1  

Sanz-Lázaro C  Marin A 《Marine environmental research》2006,62(5):374-387

Fish farming is an important source of organic matter input in coastal waters, which contributes to eutrophication. In this study, the macrofaunal benthic community was studied after the cessation of fish farming with the aim of improving our understanding of benthic succession and sediment recovery in a marine ecosystem. The results showed that the best environmental variables for assessing organic pollution were acid-volatile sulfides (AVS) and redox potential. Succession and recovery was best explained by macrofaunal analysis based on community composition as well as on trophic groups. The patterns of recovery differed between each impacted station. For this reason, succession could not be accurately predicted due to the unique environmental parameters and the singular community functional structure of each location. The Azti Marine Benthic Index (AMBI) proved its validity for assessing pollution but did not distinguish between successional stages.  相似文献   

中国大陆7级地震活动状态分析   总被引：2，自引：0，他引：2  

马宏生  邵志刚  周龙泉  蒋长胜 《地震》2008,28(3):8-13

在前人研究中国大陆地震活动的时间非平稳性认识的基础上, 将中国大陆7级以上地震活动状态划分为三类, 分别为少发时段(平静期)、 增多时段、 丛发时段(活跃期), 将这三类时段简称为: Ⅰ类时段、 Ⅱ类时段和Ⅲ类时段。 并利用显著性检验对相应划分结果进行了初步分析, 认为中国大陆可能以Ⅱ类时段为其基本状态, Ⅲ类时段和Ⅰ类时段均是在Ⅱ类时段状态上的上下偏离; 中国大陆自1901年以来的前后50余年的强震活动基本状态并没有发生显著改变, 今后一段时期内的7级以上强震活动可能仍将重复20世纪的活动规律; 1901年以来的百年资料显示, 每一个Ⅲ类时段前都存在一个Ⅱ类时段, 强震活动增强需要一个过程, 没有Ⅰ类时段直接进入Ⅲ类时段的先例; 2008年3月21日新疆于田7.3级地震的发生, 可能意味着中国大陆已进入Ⅱ类时段。  相似文献   

Trophic status of the Iranian Caspian Sea based on water quality parameters and phytoplankton diversity     

Hasan Saravi Nasrollahzadeh  Zubir Bin Din  Swee Yeok Foong  Asieh Makhlough 《Continental Shelf Research》2008

The present study attempted to test the applicability of the trophic index (TRIX) for assessing trophic status along the Iranian coast of the Caspian Sea (CS). In order to increase the sensitivity of the TRIX for this area, we defined the range (lower and upper limits) from data collected between 1994 and 2005 which have been used as a reference. Several biological and chemical water quality parameters were determined and compared with the TRIX in order to describe the water quality status of the area. Comparisons were also made on two temporarily and spatially varied trophic status at the study site. Sampling was carried out at 36 stations during Phase I (1996–1997: before the introduction of an alien species Mnemiopsis leidyi, as a background data) while 24 stations were sampled during Phase II in 2005 (after the introduction of the alien species). A Parallel Study (as supplementary data) from 16 smaller scale sampling at shallower sites was also included in the discussion (1994–2005 on 18 transects). The results show that nutrient concentration (DIN, DIP compounds), oxygen (as absolute %) deviation from saturation (aD%O), chlorophyll a and also the Caspian Sea Trophic Index (TRIXCS) increase significantly after the introduction of an alien species (p<0.01). During Phase I and the Parallel Study, the phytoplankton community was dominated (based on important species index) by Thalassionema nitzschioides, Skeletonema costatum (Chrysophyta) year round but during Phase II, Spirulina laxissma (Cyanophyta) dominated annually and in autumn, coinciding with the minimum Shannon–Weaver diversity and Evenness indices recorded. Several trophic status indices and indicators were applied and an overall analysis suggested that the area has low trophic level during Phase I and high trophic level during Phase II. During the Parallel Study, low trophic level was recorded during the pre-invasion period and high trophic level for the post-invasion period.  相似文献   

不同营养水平湖泊浮游植物吸收和比吸收系数变化特征   总被引：5，自引：0，他引：5  

王明珠  张运林  刘笑菡  朱广伟  汤祥明  周永强 《湖泊科学》2013,25(4):505-513

利用太湖和博斯腾湖8月份、天目湖6 8月份的采样数据,开展不同营养状态下浮游植物吸收和比吸收系数的变化规律研究,并探讨其影响因素.利用综合营养指数法,太湖8月42个采样点中20个点为重度富营养,标记为太湖TⅠ,22个点为中度富营养,标记为太湖TⅡ,天目湖夏季、博斯腾湖8月的富营养水平分别为轻度富营养和中营养.440 nm处浮游植物吸收系数a_ph(440)按照营养水平从高到低由重度富营养到中营养分别为1.02±0.51、0.69±0.40、0.78±0.24和0.20±0.04 m^-1,相应地675 nm处浮游植物吸收系数a_ph(675)分别为0.59±0.32、0.38±0.23、0.41±0.13和0.08±0.02 m^-1.统计检验显示,重、中度富营养的太湖以及轻度富营养的天目湖浮游植物吸收系数显著高于中营养的博斯腾湖.440 nm处浮游植物比吸收系数a_ph^*(440)分别为0.013±0.006、0.012±0.004、0.038±0.008和0.051±0.013 m²/mg Chl.a.统计检验显示,重度、中度富营养的太湖浮游植物比吸收系数显著小于轻度富营养的天目湖,而天目湖浮游植物比吸收系数又显著小于中营养的博斯腾湖.另由400~700 nm浮游植物的光谱曲线可以明显看出不同营养状态浮游植物吸收系数的变化情况,表现为:重度富营养太湖TⅠ>轻度富营养的天目湖>中度富营养的太湖TⅡ>中营养的博斯腾湖.太湖和天目湖属于富营养化湖泊,浮游植物吸收系数明显高于中营养的博斯腾湖,这充分反映了随营养程度增加,浮游植物吸收逐渐增加.天目湖浮游植物略高于太湖TⅡ是因为太湖非藻类悬浮颗粒物含量高,所以吸收系数偏小.比吸收系数的变化情况与吸收系数的变化情况恰好相反,随着营养程度的增加依次递减.随营养程度增加浮游植物吸收逐渐增加是由于水体营养盐增加促进浮游植物生长,浮游植物生物量逐渐增加所致,而比吸收系数逐渐降低则由于色素包裹效应所致.  相似文献   

Changes in diet and niche breadth of a small fish species in response to the flood pulse in a Neotropical floodplain lake     

《Limnologica》2017

This study tested the hypothesis that the flood pulse affects the diet composition and the niche breadth of Moenkhausia forestii, a small characid fish inhabiting the littoral zone of lakes. To this end, we compared the diet composition (at the population and individual levels) between hydrological periods (high and low water phases) in a floodplain lake of the Upper Paraná River. PERMANOVA revealed differences in the diet between periods (pseudoF_1,38 = 8.5; p < 0.001), with predominant consumption of chironomid larvae and Ephemeroptera (aquatic resources) in the low-water period and an increase in the contribution of terrestrial resources (Hymenoptera, Coleoptera, and Orthoptera) during the high-water period. Based on the PERMDISP results, inter-individual variability in M. forestii diet also differed between periods (F_1,38 = 5.80; p = 0.02), with higher values during the high-water period resulting in a dietary niche expansion. During the low-water period, we observed the dominance of chironomid larvae in the diets of most individuals, resulting in lower inter-individual variability and thus narrower niche breadth. The diet of M. forestii was affected by the flood pulse at both the population and individual levels. The most important difference was found in the origin of food items; during the low-water period, the diet consisted mainly of aquatic resources, and during the high-water period, there was a large contribution of terrestrial resources. This variation is related to the increased availability of allochthonous resources in the high period, when terrestrial areas are flooded by the overflow of the river, thereby increasing the input of resources into the aquatic environment. The increased availability of food resources during this period allowed the expansion of the trophic niche of M. forestii, accompanied by the highest richness (19 items) and the highest evenness of food items. Our findings demonstrated that the flood pulse affected the composition of the M. forestii diet at both the population and individual levels. These results support the importance of the flood pulse, which connects aquatic and terrestrial ecosystems, in providing food resources for fish.  相似文献   

Effects of fish and macrophytes on phytoplankton and zooplankton community structure in a subtropical freshwater reservoir     

《Limnologica》2017

Excessive macrophyte biomass and cyanobacterial blooms associated with eutrophication and possibly exotic fish frequently compromise freshwater systems. In this study, 20 large (∼3.2 m³), replicated enclosures were used to investigate the effects of piscivorous Australian bass (Macquaria novemaculeata), planktivorous gambusia (Gambusia holbrooki (Girard)), benthivorous carp (Cyprinus carpio), and macrophyte removal on water quality, as well as trophic interactions within the enclosures. Fish effects on reservoir water quality were carp > gambusia > bass. Cryptomonads spp. (54,083 cells/mL) and Anabaena spp. (47,983 cells/mL) increased significantly (63 and 23 fold, respectively) in carp enclosures, possibly because of physiological adaptation to low light, high turbidity, total phosphorus concentrations (TP) and low TN: TP ratios (N-limitation); a consequence of carp benthic grazing. Carp and gambusia caused an unconventional shift from smaller to medium sized zooplankton (e.g. Boeckella sp., Bosmina meridionalis), possibly a result of copepod nauplius grazing. In the subtropical system studied, fish-induced nutrient recycling appears more important to the outcome of bio-manipulation than grazing impacts. Macrophyte harvesting unexpectedly decreased phytoplankton biomass linked to declines in Euglenophyta and diatoms (Asterionella spp.). Cyanophyta (Oscillatoriales spp./Anabaena spp.) increased in response to macrophyte harvesting and was consistent with findings on European lakes that Cyanophyta abundance tends to be higher in the absence of macrophytes. Results indicate exotic fish removal, nutrient loading control and macrophyte conservation is important in these aquatic systems to maintain high water quality.  相似文献   

The dynamics of Chaoborus americanus in an Adirondack lake following the reintroduction of fish     

《Limnologica》2017

Acid deposition during the 20th century led to the gradual elimination of fish in Brooktrout Lake (Adirondack Mountains, New York State). Thereafter, the lake was colonized by Chaoborus americanus, a dipteran with an aquatic larval stage that typically resides in the pelagic zone in fishless lakes. During subsequent chemical recovery from acidification, the lake was stocked with Brook Trout (Salvelinus fontinalis). For seven years following this reintroduction we examined the re-adaptation of the food chain. The C. americanus abundance and distribution was quantified utilizing a combination of hydroacoustics, traditional vertical net tows and Schindler-Patalas trap collections. Hydroacoustic backscattering signals were repeatable and correlated (r = 0.86, p = 0.003) with C. americanus abundance. Backscattering, depth, month and year were used to develop a random forest model that predicted the C. americanus density (r² = 0.67,  p< 0.05). The hydroacoustic signal revealed a clear but limited diurnal vertical migration of C. americanus. The signal continued in the presence of the fish population beginning with reintroduction in 2005 and extending through 2011. In 2012, the hydroacoustic signal no longer was present in the lake, suggesting that the fish had eliminated the C. americanus population, which was verified with net tows. Using novel and traditional survey methods, we demonstrate that the reintroduction of fish can alter the lake community structure significantly through the extirpation of the major component of the pelagic zone.  相似文献   

Can UV radiation affect benthic deposit-feeders through biochemical alteration of food resources? An experimental study with juveniles of the benthic polychaete Eupolymnia nebulosa     

Nahon S  Pruski AM  Duchêne JC  Méjanelle L  Vétion G  Desmalades M  Charles F 《Marine environmental research》2011,71(4):266-274

The growth, tentacle development and feeding activity of the benthic polychaete Eupolymnia nebulosa were examined to determine whether UV might affect marine deposit-feeders indirectly through the modification of the nutritional quality of their resources. Since marine invertebrates have higher nutritional requirements during the period following settlement, we tested the effect of UV-altered phytodetritus on freshly settled juveniles of E. nebulosa. Phytodetritus was prepared from cultures of the diatom Skeletonema costatum either grown under or sheltered from UVB radiation. Sterol content of phytodetritus was unmodified by UV radiation. Conversely, phytodetritus was noticeably depleted in polyunsaturated fatty acids. Growth and tentacle development of juveniles fed on altered phytodetritus were reduced by 35% and 15% respectively, suggesting potential deficiencies in essential nutrients. In response to the lower quality of the phytodetritus, juveniles explored a wider area as they search for food, a strategy that could compensate for low food quality.  相似文献   

北京市地质环境监测现状及对策研究     

张金玲 《城市地质》2015,(2):5-11

分析了北京市开展地质环境监测的必要性,介绍了北京市地勘局对北京市地质环境监测工作战略:"首都地质资源环境承载能力监测预警平台建设工程",总结了北京市地质环境监测现状及存在的不足,对未来北京市地质环境监测工作提出了编制北京市地质环境监测规划、做好监测网络技术支撑工作、逐步建设和完善北京市地质环境监测体系的对策。  相似文献