应用草型塘模型生态系统研究化学品的整体生态效应

本文叙述草型塘模型生态系统的结构、功能及应用于评价化学品引起生态效应的可能性。模型塘由８个３ｍ×１ｍ×１ｍ（Ｖ＝３ｍ￣３）的玻璃钢水槽组成。每个槽的底部铺设１０ｃｍ厚的带有水生生物种子、孢子和卵子的河泥,灌注自来水,添加一定量的ＫＮＯ＿３和ＮａＨ＿２ＰＯ＿４．使起始氮、磷含量达到中－富营养水平。在室外自然光照条件下培养,实验历时４个多月。经１个多月的培养,各槽即形成结构复杂的沉水植物群落,除各种常见的沉水植物外,尚有多种藻类、浮游动物、底栖动物及微生物。各群落之间的相似性较好,藻类、浮游甲壳类及底栖动物多样性指数变异系数分别为１７．７％、１８．０％和３６．０％。群落功能稳定,９月中旬各槽群落总产氧量平均为５．７５±０．３０ｇ／ｍ￣２·ｄ’Ｐ／Ｒ比值平均为１．２６±０．０７,二者的变异系数分别为５．２％和５．６％。经单甲脒农药污染影响实验,本模型生态系统中的群落结构及功能产生一系列明显反应。说明草型塘模型生态系统结构、功能比较复杂,稳定,可比性较强,对药物污染反应灵敏,是生态系统水平上生态效应评价的良好工具。     

Hydroperiods of created and natural vernal pools in central Ohio: A comparison of depth and duration of inundation

Water levels were recorded weekly from six natural vernal pools and 10 created vernal pools at two forested wetland complexes in central Ohio. Vernal pool median water depth and duration of inundation were significantly greater at the created vernal pools than at the natural vernal pools (α = 0.05, P < 0.05). The average period of inundation for created pools was 309 ± 32 days, compared with 250 ± 16 days for natural pools. The created pools produced a range of inundation times, from 163 to 365 days in length, with three pools permanently inundated.     

Benthic resources are the key to Daphnia middendorffiana survival in a high arctic pond

1. Shallow arctic lakes and ponds have simple and short food webs, but large uncertainties remain about benthic–pelagic links in these systems. We tested whether organic matter of benthic origin supports zooplankton biomass in a pond in NE Greenland, using stable isotope analysis of carbon and nitrogen in the pond itself and in a ¹³C‐enrichment enclosure experiment. In the latter, we manipulated the carbon isotope signature of benthic algae to enhance its isotopic discrimination from other potential food sources for zooplankton. 2. The cladoceran Daphnia middendorffiana responded to the ¹³C‐enrichment of benthic mats with progressively increasing δ¹³C values, suggesting benthic feeding. Stable isotope analysis also pointed towards a negligible contribution of terrestrial carbon to the diet of D. middendorffiana. This agreed with the apparent dominance of autochthonous dissolved organic matter in the pond revealed by analysis of coloured dissolved organic matter. 3. Daily net production by phytoplankton in the pond (18 mg C m^?2 day^?1) could satisfy only up to half of the calculated minimum energy requirements of D. middendorffiana (35 mg C m^?2 day^?1), whereas benthic primary production alone (145 mg C m^?2 day^?1) was more than sufficient. 4. Our findings highlight benthic primary production as a major dietary source for D. middendorffiana in this system and suggest that benthic organic matter may play a key role in sustaining pelagic secondary production in such nutrient‐limited high arctic ponds.     

A study on distribution of natural radionuclide polonium-210 in a pond ecosystem

This paper presents the results of an investigation on the distribution of²¹⁰Po in Mutharasanallur pond ecosystem. It has been demonstrated that²¹⁰Po is non-uniformly distributed within the ecosystem. The results of the study show a dissolved²¹⁰Po concentration in pond water of 1 4mBq 1₋₁. The sediment samplso recorded a²¹⁰Po activity of 59 9 Bq kg₋₁. The aquatic organisms showed differential accumulation of the radionuclide with enhanced bioaccumulation in soft tissues and muscle. The²¹⁰Po activity in the biota fell within the range of 1·2–53 3 Bq kg₋₁ (wet wt). The bivalve mussel,Lamellidens marginalis was identified to accumulate higher concentration of²¹⁰Poin soft tissues, suggesting that these organisms could serve as a bio-monitor of²¹⁰Po radionuclide in a freshwater system. The concentration factors of²¹⁰Po for the biotic components ranged from ∼10²–∼10⁴. Analyses of the results indicate that prawn and fish represent an important source of supply of²¹⁰Po to humans via dietary intake. Results of²¹⁰Po activity in the abiotic and biotic components of the pond ecosystem were higher when compared with those of Cauvery river system, the primary water source of the pond.     

温度对黄喉拟水龟性别决定的影响

研究了不同孵育温度对黄喉拟水龟(MauremysmuticaCantor)性别决定的影响,同时分析了孵育温度对胚胎发育及成活率的影响。实验设置的3个孵化温度为(25±0.5)℃,(29±0.5)℃和(33±0.5)℃。每一温度指标下设置40枚受精卵。在实验温度内,胚胎的发育速度随着孵化温度的升高而加快,所用的孵育时间也越来越短。孵化累积温度CTUs在25℃时最高,在29℃时最低,而33℃时则居中,在25℃和29℃时,孵化成活率较高,均达到97.5%。在33℃时孵化成活率只有67.5%,而在孵出的稚龟中亦有一定数量的畸形龟,累积孵化温度也高于29℃时的CTUs,说明33℃的孵育温度对胚胎发育有不利影响,预示33℃已临近其胚胎发育的存活阈(Survivalthreshold)。在25℃时,雄性子代占优势,雌性率为23.7%;在33℃时,雌性子代占绝对优势,雌性率为94.7%;在29℃时,性比达到平衡,雌性率为50%。经X2检验,在25℃及33℃时的性比与依赖概率估计的性比(1∶1)有极显著的差异(p<0.005),这种显著的偏离说明黄喉拟水龟的性别决定属于TSD机制,而且可能属于其中的TSDⅠ型,即高温产生雌性子代,低温产生雄性子代。而29℃可能是黄喉拟水龟性别决定的临界温度。     

Degradation of softwood [14C lignin] lignocelluloses and its relation to the formation of humic substances in river and pond environments

The fate of lignin in water and sediment of the Garonne river (France) and of a pond in its floodplain was examined using specifically labeled [¹⁴C-lignin] lignocelluloses. No significant differences appeared in the mineralization rate of alder, poplar or willow [¹⁴C-lignin] in running water samples. Conversion of total radioactivity to ¹⁴CO₂ ranged between 18.7% and 24.4% after 120 days of incubation. Degree of ¹⁴C-labeled lignin mineralization in standing water and sediments was clearly lower, especially in submerged sediments, and was correlated with oxygen supply. After 60 days of incubation 3.3% to 7.9% of the ¹⁴C-labeled lignin was recovered in water samples as dissolved organic carbon originating from microbial metabolism. In water extracts from sediment the percentage of dissolved organic ¹⁴C was only 0.4% to 1.3% of the applied activity. In the humic fraction extracted from sediments it did not exceed 4.4% which was much lower than in soils. No significant difference appeared between river and pond conditions for humic substances formation.     

产油微藻的筛选及大规模培养的研究进展

产油微藻具有生长速度快、油脂含量高和抗逆性强等特点,是极具生产潜力的生物柴油的原料.微藻生物柴油技术包括微藻藻种的筛选、大量培养和采收、油脂的提取和生物柴油的制备.该文对近些年产油微藻藻种的筛选和规模化培养的研究进展进行综述.     

Elaboration of an algae‐to‐energy system and recovery of water and nutrients from municipal sewage

Increasing pressure is being exerted on the peri‐urban space that has elevated the demand for electricity, affects the global water resource, and impacts the potential to produce food, fiber, and commodity products. Algae‐based technologies and in particular algae‐based sewage treatment provides an opportunity for recovery of water for recycle and re‐use, sequestration of greenhouse gases, and generation of biomass. Successful coupling of municipal sewage treatment to an algae‐to‐energy facility depends largely on location, solar irradiance, and temperature to achieve meaningful value recovery. In this paper, an algae‐to‐energy sewage treatment system for implementation in southern Africa is elaborated. Using results from the continued operation of an integrated algal pond system (IAPS), it is shown that this 500‐person equivalent system generates 75 kL per day water for recycle and re‐use and, ～9 kg per day biomass that can be converted to methane with a net energy yield of ～150 MJ per day, and ～0.5 kL per day of high nitrogen‐containing liquid effluent (>1 g/L) with potential for use as organic fertilizer. It is this opportunity that IAPS‐based algae‐to‐energy sewage treatment provides for meaningful energy and co‐product recovery within the peri‐urban space and, which can alleviate pressure on an already strained water–energy–food nexus.     

轮虫培育池生态系统各有机碳库储量及其日变化

2001年5～6月对辽宁省盘锦光合水产有限公司的两种模式轮虫培育池有机碳库储量及动态进行了研究.结果表明,静水池溶解有机碳（DOC）和颗粒有机碳（POC）库储量平均值分别为5.69±2.90 mg·L^-1和24.56 ± 2.12 mg·L^-1;流水池DOC和POC分别为9.61±3.17 mg·L^-1和24.13 ±2.91 mg·L^-1.流水池和静水池TOC、DOC和POC的比例分别为 1∶0.75∶0.25和1∶0.82∶0.18.POC含量高的池塘DOC含量也较高.流水池的POC、DOC周日变动幅度大,静水池昼夜变动幅度小.流水池POC含量白天(5:00～17:00)升高,静水池降低,夜间(15:00～23:00)两池POC含量均降低.从23:00至次日5:00上升,两池分别在17:00和5:00达到高峰.白天(5:00～17:00) 流水池DOC/POC升高,静水池降低;夜间(17:00～23:00)两池均上升,23:00 至次日5:00则呈下降趋势.