内蒙古岱海水体营养状况分析

岱海是我国半干旱区的一个典型内陆湖。近年来,由于受到流域人类活动的强烈干预,湖泊水位持续下降,湖面不断萎缩。与此同时,湖泊水质也呈现出明显的恶化趋势,2004年水质监测结果显示,湖水中TN、TP和CODMn均出现超标,全湖水质达到劣Ⅴ类。采用综合营养状态指数法进行评价,岱海水体已处于中度富营养化水平,但受湖周生产布局的影响,营养状况空间分布有所差异,自湖西向湖东,营养状态指数逐渐减小,富营养化程度也相应降低。在时间变化上,岱海已由1996年的中营养化过渡到2004年的中度富营养化,上升了两个营养级别。引起岱海水质恶化的原因主要是农田地表径流及城镇所产生的生活污水,另外,湖泊的不断萎缩也是一个不容忽视的影响因素。为防止岱海水环境继续恶化,根据流域特点提出了一些具体的防治对策和建议。     

Reconstructing past eutrophication trends from diatoms and biogenic silica in the sediment and the pelagic zone of Lake Constance, Germany

In Lake Constance, phosphorus concentrations and the seasonal development of phytoplankton communities in water samples from the pelagic zone were regularly recorded since the 1950's. Before the 1950's, there were occasional investigations of plankton communities since 1896. We compared these data with the sedimentary record in two sediment cores. Then, the eutrophication history of Lake Constance was inferred from diatoms. The record of biogenic silica in the cores is discussed with respect to diatom biomass increase.Diatom assemblages in the sediment cores precisely reflected the pelagic diatom development for the period 1971--1992. Both sediment cores and the water samples have a high interannual variability of diatom assemblages. Below a sediment depth of 27 cm (AD 1920), more than 50% of the diatoms were partly corroded, and we limited the reconstruction of trophic state changes to the interval of 1920--1993. Oligotrophic conditions of Lake Constance were indicated by the dominance of various Cyclotella taxa from 1920 to 1940. Since 1939/1940, increasing abundance of it Tabellaria fenestrata showed oligotrophic to mesotrophic conditions. Between 1953 and 1956, increasing Stephanodiscus hantzschii and disappearing Cyclotella indicated advanced eutrophication and total phosphorus values ranged between 8--10 mg m-3 during turnover in late winter. Further eutrophication was shown by disappearing T. fenestrata and increasing S. minutulus in 1963. Maximum TP concentrations of 87 mg m-3 occurred in 1979/80 and was accompanied by increasing abundances of Aulacoseira granulata. From 1986 to 1992, reoccurrence of Tabellaria fenestrata and Cyclotella indicate some recovery of Lake Constance.Biogenic silica and diatom abundances were similar among cores but indicate a 3--4 fold increase of diatom biomass only. This was far below the estimate of biomass increase from sedimentary pigment data (25 fold) and the estimate of phytoplankton data from the literature (70 fold).     

Basic limnological characteristics of the shallow eutrophic lake Grimnitzsee (Brandenburg, Germany)

The medium shallow lake Grimnitzsee (maximum depth: 9.9 m; mean depth: 4.6 m; area: 7.7 · 10⁶ m²) which is situated in the biosphere reserve “Schorfheide-Chorin” in northern Brandenburg (Germany) was studied in 1994 and 1995. A bathymetric map of Grimnitzsee is given for the first time. The lake is usually polymictic although in 1994 and 1995 relatively long summer stratification was observed due to very high global radiation input. Nutrient concentration, light climate, oxygen status, phytoplankton biomass and the species composition of littoral diatoms characterize the lake as eutrophic. Special features deducible from the lake's polymictic character were the multiple development of aerobic or anaerobic strata above the sediment, the fast recovery of silicon concentration in the water column after diatom sedimentation, the importance of resuspension for the success of planktonic diatom populations, and an only moderate correlation between chlorophyll a concentration and light attenuation as well as seston dry weight probably due to the influence of suspended particles.     

应用氮稳定同位素技术对雷州湾海域主要鱼类营养级的研究

1引言海洋食物网是维系海洋生态系统发展的基础,也是海洋生态学基础理论研究的主要内容之一。海洋食物网研究是通过对多种海洋鱼类食物关系的综合分析,了解其种间关系,阐明营养级的能流途径,可为海洋生态系统修复、改善海洋生态环境、保护海洋生物多样性和进一步合理开发利用海洋生物资源提供科学依据。     

类生物量锥体

对北海鱼类营养级和生物量进行了综合分析,北海鱼类群落中,浮游生物食性、底栖生物食性和游泳生物食性鱼类的平均营养级分别为3.5,3.9和4.5,依次递增,而它们的生物量之比为1∶0.8∶0.4,依次递减,由此发现了一种与生物量锥体相似而又不同的现象,即捕食者与捕食者之间横向的营养级与生物量的负相关关系,作者称之为类生物量锥体。北海的生物量锥体其底部与顶部营养级之比为1∶4,生物量之比为1333∶1;类生物量锥体其底部与顶部营养级之比为3.5∶4.5,生物量之比只有2.36∶1,由此看出类生物量锥体相似于生物量锥体,但又不同于Odum提出的被食者与捕食者之间的纵向关系的生物量锥体,其生物量的变化幅度较生物量锥体为小。类生物量锥体的意义在于可以从鱼类生态类群营养级的高低来推测其生物量的状况。     

广东沿海红树林区水质变化特征与富营养状态评估

调查了广东红树林区水质的时空变化, 分别采集了红树林区表层水体水样旱季30个样点(2017年10月至2018年1月)和湿季20个样点(2018年7月至8月)进行分析。利用单一营养状态指数(TSI Chl a)评价红树林水质特征和营养状态, 评价标准: 050为富营养, >70为高营养。红树林区环境参数的时空变化为: 盐度(2.15‰~27.14‰)、pH (6.18~8.65)、电导率(10.87~90.52µs·cm^-1)、浊度(0.0975~21.61FTU)、硝酸盐(0~127.2mg·L^-1)、亚硝酸盐(0~12.0mg·L^-1)、磷酸盐(0~34.5mg·L^-1)、硅酸盐(1.22~2.88mg·L^-1)和叶绿素a (0.19~38.08mg·m^-3)。聚类分析表明, 丰水期横跨雷州半岛右侧至广东沿海东部的水质相对较好, 而左侧则处于中营养化状态。同时, 在枯水期, 红树林区水质较差, 从雷州半岛周围的高中营养化状态, 到广东沿海东部的富营养化状态。主成分分析表明, 营养盐、盐度、pH、电导率(electrical conductivity, EC)和浊度对红树林区水质状况贡献显著, 进而影响红树林生态系统中藻类群落的变化。     

黄淮海平原封丘试区水体营养状态的综合评价

选择封丘试区内有代表性的7类水体,对其营养状态进行综合评价和聚类分析,初步提出了用于水体营养状态评价的方法和标准。结果表明:各水体营养状态可依其植物组成而明显分成挺水植物、沉水植物和浮游植物型等,而且草型水体的营养指数均高于藻型水体。总的看来,该试区各类水体营养状态较为相似,营养指数均很高,属富营养—重富营养型,渔业发展潜力较大。     

Effect of temperature on an alga‐grazer trophic transfer: A dual stable isotope (13C, 15N) labeling experiment

In this study, we examined the impact of temperature on the carbon and nitrogen trophic transfers from a macroalga to a macro‐grazer by the use of dual ¹³C‐ and ¹⁵N‐labeling. Using an experimental approach in mesocosms, individuals of the urchin Psammechinus miliaris were maintained for 1 month at 17°C (mean summer temperature in the Bay of Brest) and at 20°C (maximum summer temperature) and fed with ¹³C‐ and ¹⁵N‐labeled Solieria chordalis. The results showed that the urchins’ ¹³C uptake was 0.30 µg¹³C g dry weight (DW)^?1 at 17°C and 0.14 µg¹³C g DW^?1 at 20°C at the end of the experiment. The lower uptake at the higher temperature may be attributed to a decrease in metabolic activity at 20°C, involving lower feeding and/or respiration rates. Conversely, no significant effect of temperature was detected on ¹⁵N uptake. At the end of the experiment, the urchins’ ¹⁵N uptake was 0.04 µg¹⁵N g DW^?1 at 17°C and 0.03 µg¹⁵N g DW^?1 at 20°C. This suggests that temperature may affect carbon and nitrogen trophic fluxes differently. The use of dual isotope labeling offers interesting prospects and needs to be further extended in order to better understand trophic interactions in marine communities and the consequences of current environmental changes, such as global warming.     

Annual pattern of zooplankton communities and their environmental response in a subtropical maritime channel system in the northern Bay of Bengal, Bangladesh

Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environmental drivers were studied in the Kohelia channel, Bangladesh from summer 2014 to spring 2015. Samples were collected using net at a depth of 1 m. A total of 32 species belonged to 18 orders, 27 families and 15 taxonomic groups were identified. Of these species, 22 distributed in all four seasons of which 8 were dominant and highly contributing to the total communities. Species number peaked in summer next to winter and fall in spring while maximum abundance was in summer and minimum in spring. Multivariate analyses showed that there was a clear annual pattern in the zooplankton communities. Species diversity and evenness peaked in spring but fall in autumn while the high value of species richness was found in winter. Biological-environmental best matching (BIO-ENV) analyses conformed that community pattern of zooplankton was mainly driven by transparency salinity, and temperature individually or combined with water nutrients. These results demonstrate that annual pattern of the zooplankton community shaped by channel environmental factors in subtropical channel ecosystems, thus might be used for community-based subtropical coastal water bioassessment.     

九龙江口红树林保护区水体浮游植物群落结构及营养状态评价

于2016年1月(冬季)、4月(春季)、7月(夏季)以及10月(秋季)对九龙江口红树林保护区的浮游植物多样性组成及其时空变化进行研究.结果表明,福建九龙江口红树林保护区共采集到浮游植物5门91属138种,其中硅藻占50.00%、绿藻占31.16%、蓝藻占8.70%、甲藻和裸藻各占5.07%.主要优势种为具槽直链藻(Melosira sulcata)、中肋骨条藻(Skeletonema costatum)、条纹小环藻(Cyclotella stratia)、舟形藻(Navicula sp.)、粗针杆藻(Synedra robusta)和菱形藻(Nitzschia sp.);浮游植物细胞数量在0.82×105~4.55×105个/dm3之间,年平均数量为1.97×105个/dm3.浮游植物种类时空变化明显,而数量的空间变化较大,季节变化不太明显.Shanno-Wiener指数、Margalef丰富度指数和Pielou均匀度指数变化范围分别为2.10~3.55、1.05~3.61、0.78~0.95.多样性指数及浮游植物生物量评价结果显示,九龙江口红树林保护区的水体为中营养状态,水质较好,但仍应加强对陆源径流和养殖废水排放进入红树林的控制和管理.