Methane and carbon dioxide fluxes from a shallow hypereutrophic subtropical Lake in China

Up to now, there have been few studies in the annual fluxes of greenhouse gases in lakes of subtropical regions. The fluxes of methane (CH4) and carbon dioxide (CO2) across air-water interface were measured in a shallow, hypereutrophic, subtropical Lake Donghu (China) over a year cycle, using a static chamber technique. During the year, Lake Donghu emitted CH4 and CO2; the average flux of CH4 and CO2 was 23.3 +/- 18.6 and 332.3 +/- 160.1 mg m(-2) d(-1), respectively. The fluxes of CH4 and CO2 showed strong seasonal dynamics: CH4 emission rate was highest in summer, remaining low in other seasons, whereas CO2 was adsorbed from the atmosphere in spring and summer, but exhibited a large emission in winter. Annual carbon (C) budget across air-water interface in Lake Donghu was estimated to be 7.52 +/- 4.07 x 10(8) g. CH4 emission was correlated positively with net primary production (NPP) and temperature, whereas CO2 flux correlated negatively with NPP and temperature; however, there were no significant relationships between the fluxes of CH4 and CO2 and dissolved organic carbon, a significant difference from boreal lakes, indicating that phytoplankton rather than allochthonous matter regulated C dynamics across air-water interface of subtropical lake enriched nutrient content. (c) 2005 Elsevier Ltd. All rights reserved.

Isolation and characterization of six microsatellite markers in the large yellow croaker (Pseudosciaena crocea Richardson)

Six polymorphic microsatellite markers were isolated and characterized using an enriched library technique in the large yellow croaker (Pseudosciaena crocea Richardson, 1864), a commercially important marine fish in China. They showed PIC (polymorphism information content) ranging from 0.064 to 0.885 (average of 0.580) and allele numbers ranging from two to 13 (average of 7.5), which were useful for the studies on population genetics and selective breeding of the large yellow croaker.

Discharges and sediments as sources of extracellular alkaline phosphatase in a shallow Chinese eutrophic lake

Total alkaline phosphatase activity (APA) and soluble reactive phosphorus (SRP) concentrations were measured in municipal wastewater, and a shallow Chinese freshwater lake receiving it. Activities of Dissolved alkaline phosphatase ( ADAP) in overlying and interstitial water were also analyzed monthly at three sites for several years. The lake was enriched with SRP and alkaline phosphatase by discharge of the wastewater, indicating that the inclusion of APA for estimating water pollution was reasonable. Annual data showed that APA in coarser fraction was significantly higher at the site receiving more wastewaters, both in surface and overlying water, suggesting that resuspension of enzyme most likely occurred in the basin heavily discharged. ADAP was an order of magnitude higher in the wastewater than those in lake waters, and was generally higher in interstitial water, a feature more striking at the site receiving more discharges. Besides, it was irrespectively inhibited by Na2WO4, L-cysteine and EDTA-Na, but stimulated by Cu2+, Zn2+, CTAB and Triton X-100 in interstitial, overlying and surface waters. This similarity of responding patterns to the stressors indicated an analogy between dissolved alkaline phosphatase in water column and that in interstitial water, supporting the hypothesis that the polluted sediments act as source of dissolved alkaline phosphatase in eutrophic lakes.

Effects of CO2 concentrations on the freshwater microalgae, Chlamydomonas reinhardtii, Chlorella pyrenoidosa and Scenedesmus obliquus (Chlorophyta)

In order to investigate the possible impacts of increased atmospheric CO2 levels on algal growth and photosynthesis, the influence of CO2 concentration was tested on three planktonic algae (Chlamydomonas reinhardtii, Chlorella pyrenoidosa, and Scenedesmus obliquus). Increased CO2 concentration enhanced significantly the growth rate of all three species. Specific growth rates reached maximal values at 30, 100, and 60 muM CO2 in C. reinhardtii, C pyrenoidosa, and S. obliquus, respectively. Such significant enhancement of growth rate with enriched CO2 was also confirmed at different levels of inorganic N and P, being more profound at limiting levels of N in C pyrenoidosa and P in S. obliquus. The maximal rates of net photosynthesis, photosynthetic efficiency and light-saturating point increased significantly (p<0.05) in high-CO2-grown cells. Elevation of the CO2 levels in cultures enhanced the photoinhibition of C. reinhardtii, but reduced that of C pyrenoidosa and S. obliquus when exposed to high photon flux density. The photo-inhibited cells recovered to some extent (from 71% to 99%) when placed under dim light or in darkness, with better recovery in high-CO2-grown C. pyrenoidosa and S. obliquus. Although pH and pCO(2) effects cannot be distinguished from this study, it can be concluded that increased CO2 concentrations with decreased pH could affect the growth rate and photosynthetic physiology of C. reinhardtii, C. pyrenoidosa, and S. obliquus.

Detection of hepatotoxic Microcystis strains by PCR with intact cells from both culture and environmental samples

Microcystins are small hepatotoxic peptides produced by a number of cyanobacteria. They are synthesized non-ribosomally by multifunctional enzyme complex synthetases encoded by the mcy genes. Primers deduced from mcy genes were designed to discriminate between toxic microcystin-producing strains and non-toxic strains. Thus, PCR-mediated detection of mcy genes could be a simple and efficient means to identify potentially harmful genotypes among cyanobacterial populations in bodies of water. We surveyed the distribution of the mcyB gene in different Microcystis strains isolated from Chinese bodies of water and confirmed that PCR can be reliably used to identify toxic strains. By omitting any DNA purification steps, the modified PCR protocol can greatly simplify the process. Cyanobacterial cells enriched from cultures, field samples, or even sediment samples could be used in the PCR assay. This method proved sensitive enough to detect mcyB genes in samples with less than 2,000 Microcystis cells per ml. Its accuracy, specificity and applicability were confirmed by sequencing selected DNA amplicons, as well as by HPLC, ELISA and mouse bioassay as controls for toxin production of every strain used.

Daily production and photosynthetic characteristics of Nostoc flagelliforme grown under ambient and elevated CO2 conditions

Diurnal photosynthesis of Nostoc flagelliforme was investigated at varied levels of CO2 concentrations and desiccation in order to estimate the effects of enriched CO2 and watering on its daily production. Photosynthetic activity was closely correlated with the desiccated status of the algal mats, increased immediately after watering, reached a maximum at moderate water loss, and then declined with further desiccation. Increased CO2 concentration enhanced the diurnal photosynthesis and raised the daily production. Watering twice per day enhanced the daily production due to prolonged period of active photosynthesis. The values of daily net production were 1321280 mumol CO2 g (d. wt)(-1) d(-1), corresponding to about 0.6-6.1% daily increase in dry weight. High-CO2-grown mats required higher levels of photon flux density to saturate the alga's photosynthesis in air. Air-grown mats showed higher photosynthetic affinity for CO2 and higher levels of dark respiration compared with high-CO2-grown samples.

Effects of CO2 enrichment on microstructure and ultrastructure of two species of freshwater green algae

order to investigate the morphological response of freshwater green algae to elevated CO2 concentration, Chlamydomonas reinhardtii Dang and Scenedesmus obliquus Kutz were cultured with enriched CO2, and their microstructure and ultrastructure were examined by microscopy and electron microscopy. The effect of CO2 enrichment to 186 mumol/L, was insignificant on the shape and size of C. reinhardtii, but significant in reducing the volume of S. obliquus. High-CO2 increased the amount of chloroplast. The pyrenoids occurred in low-CO2-grown cells but not in high-CO2-grown ones and more starch granules were observed in the former.

Vertical variations in kinetics of alkaline phosphatase and P species in sediments of a shallow Chinese eutrophic lake (Lake Donghu)

The vertical distribution of the variables relevant to P forms in sediments were studied in a shallow Chinese freshwater lake (Lake Donghu) in 1997, 1998, 1999 and 2000, to assess the contribution of enzyme to P availability in sediment cores. Sediment P was fractionationd into iron-bound P, calcium-bound P, acid soluble organic P (ASOP) and hot NaOH extractable residual organic P. The former two species made the largest contribution to the sediment P pool. All P species exhibited significantly higher concentrations in different depths at Station I, compared with those found at Station II, except for ASOP. Coupled with these lower ASOP concentrations, the V-max data of alkaline phosphatase, measured on the same samples, were significantly higher at station I. Taken together, ASOP were probably important in supplying the enzymatic substrate (Phosphatase Hydrolyzable Phosphorus, PHP) into interstitial water. Dissolved orthophosphate and PHP concentrations were highly heterogeneous , but peaked in subsurface, paralleled by higher V-max and lower K-m values of alkaline phosphatase, throughout the sediment core. Sediment in the eutrophic lake is not only enriched in available P (iron-bound P), or stores residual P, but also tends to release PHP, thereby inducing the production of alkaline phosphatase and releasing o-P into water column by enzymatic hydrolysis. The latter process may also occur in relatively deep sediment layers.

Growth of Potamageton maackianus under low-light stress in eutrophic water

Decline of submersed macrophytes in Lake Donghu of China with the progress of eutrophication is assumedly due to low light stress by algae blooming. I conducted a laboratory experiment to study the impact of low-light stress on the growth of Potamogeton maackianus A. Been, a dominant submersed macrophyte of the lake before the 1970s. Plants were grown for six weeks in aquaria with Lake Donghu sediment and enriched water. Light delivered to aquaria was adjusted to simulate the typical Lake Donghu light intensities that exist at several water depths from 0.6m to 1.7m. Biomass growth of the plant was inversely related to light intensity at the simulated depths of greater than or equal to 1.0m (r = 0.96, p < 0.05, n=6) and was negative at the depths of greater than or equal to 1.4m. These results indicate that photosynthetic light saturation and compensation points of the plant in Lake Donghu should be ca. 0,9m and ca. 1.5m depths, respectively. Chlorophyll content, growth of main shoot, total shoot lengths and density of the plant all peaked at 1.2-1.3m simulated depths. These results indicate that P. maackianus responds to low light stress primarily by elongation of shoots, and increase of density. Its biomass growth and nutrient uptake rate did not correlate with the accelerated shoot growth. Below the light intensities of water deeper than 1.2-1.3m, shoot growth rate decreased. The flexible tolerant strategy of P. maackianus to low-light stress suggests that the disappearance of this plant from the lake was not mainly due to eutrophication-induced low-light stress.

Influence of CO2, light and watering on growth of Nostoc flagelliforme mats

The terrestrial blue-green alga (cyanobacterium), Nostoc flagelliforme, was cultured in air at various levels of CO2, light and watering to see their effects on its growth. The alga showed the highest relative growth rate at the conditions of high CO2 (1500 ppm), high light regime (219-414 mu mol m(-2)s(-1)) and twice daily watering, but the lowest rate at the conditions of low light (58-114 mu mol m(-2)s(-1)) and daily twice watering. Increased watering had little effect on growth rate at 350 ppm CO2, but increased by about 70% at 1500ppm CO2 under high light conditions. It was concluded that enriched CO2 could enhance the growth of N. flagelliforme when sufficient light and water was supplied.

Species transformation of trace elements and their distribution prediction in dyestuff residue incineration

The release of heavy metals from the combustion of hazardous wastes is an environmental issue of increasing concern. The species transformation characteristics of toxic heavy metals and their distribution are considered to be a complex problem of mechanism. The behavior of hazardous dyestuff residue is investigated in a tubular furnace under the general condition of hazardous waste pyrolysis and gasfication. Data interpretation has been aided by parallel theoretical study based on a thermodynamic equilibrium model based on the principle of Gibbs free energy minimization. The results show that Ni, Zn, Mn, and Cr are more enriched in dyestuff residue incineration than other heavy metals (Hg, As, and Se) subjected to volatilization. The thermodynamic model calculation is used for explaining the experiment data at 800 degrees C and analyzing species transformation of heavy metals. These results of species transformation are used to predict the distribution and emission characteristics of trace elements. Although most trace element predictions are validated by the measurements, cautions are in order due to the complexity of incineration systems.

Density Gradient Ultracentrifugation of Nanotubes: Interplay of Bundling and Surfactants Encapsulation

Density gradient ultracentrifugation (DGU) has emerged as a promising tool to prepare chirality enriched nanotube samples. Here, we assess the performance of different surfactants for DGU. Bile salts (e.g., sodium cholate (SC), sodium deoxycholate (SDC), and sodium taurodeoxycholate (TDC)) are more effective in individualizing Single Wall Carbon Nanotubes (SWNTs) compared to linear chain surfactants (e.g., sodium dodecylbenzene sulfonate (SDBS) and sodium dodecylsulfate (SDS)) and better suited for DGU. Using SC, a narrower diameter distribution (0.69-0.81 nm) is achieved through a single DGU step on CoMoCAT tubes, when compared to SDC and TDC (0.69-0.89 nm). No selectivity is obtained using SDBS. due to its ineffectiveness in debundling. We assign the reduce selectivity of dihydroxy bile salts (S DC and TDC) in comparison with trihydroxy SC to the formation of secondary micelles. This is determined by the number and position of hydroxyl ( OH) groups on the a-side of the steroid backbone. We also enrich CoMoCAT SWNT in the 0.84-0.92 nm range using the Pluronic F98 triblock copolymer. Mixtures of bile salts (SC) and linear chain surfactants (SOS) are used to enrich metallic and semiconducting laser-ablation grown SWNTs. We demonstrate enrichment of a single chirality, (6,5), combining diameter and metallic versus semiconductillg separation on CoMoCAT samples.

大熊猫“盛林1号”放归监测

大熊猫(Ailuropoda melanoleuca)是我国特有的珍稀濒危物种，国家Ⅰ级重点保护野生动物，被称为“国宝”。目前，大熊猫被局限在我国中西部的岷山、邛崃、大相岭、小相岭、凉山和秦岭6大山系中。对大熊猫的保护和研究，我国政府、保护生物学科研人员、社会各界及国际保护组织都做了大量的工作。根据全国三次大熊猫调查结果显示，大熊猫栖息地片段化现象依然存在，形成多个隔离的大熊猫小种群。尤其在小相岭、大相岭、岷山B和岷山C种群，大熊猫数量较少，且栖息地破碎，面临较大威胁。有的山系大熊猫种群数量些已低于最小可存活大熊猫种群的数量，如果不采取人工措施，这些种群的大熊猫存在灭绝的危险。 将圈养大熊猫放归野外，以补充野外大熊猫种群数量，增加其遗传多样性，复壮和扩大野生大熊猫种群，是大熊猫人工繁育的最终目标。为降低放归的风险性，在放归人工繁育大熊猫前，将救护存活的野生大熊猫先有计划放归野外，并对其进行跟踪监测，对积累大熊猫放归经验，进一步研究大熊猫野外生物学习性，丰富放归地大熊猫种群遗传多样性，为人工繁育大熊猫放归野外夯实基础，具有十分重要的意义。2005年8月8日，国家林业局和四川省人民政府联合将救护野生大熊猫“盛林1号”放归于龙溪－虹口国家级自然保护区内岷山B大熊猫种群栖息地，并进行系统监测研究。成功的积累了一些放归经验和放归大熊猫的生物学资料，为人工繁育大熊猫的放归奠定了一定基础。 2005年8月至2007年6月期间，我们采用GPS无线电项圈、粪便DNA检测和红外线自动触发相机陷阱的方法，对大熊猫“盛林１号”进行了追踪监测，获得了以下成果： 1.通过分析“盛林1号”放归后了活动趋势和采用两种贝叶斯方法，利用目前五大山系的已有微卫星遗传数据，检测“盛林１号”与五大山系的遗传关系的远近，推测其来源于邛崃山系的可能性较大。 2.收集了大量“盛林1号”野外生境选择数据。我们认为“盛林1号”放归后经历了应急期、初步稳定期、长途迁徙期三个阶段（这可能是今后放归大熊猫都必经的三个时期），并与当地大熊猫种群已发生交流。目前“盛林１号”仍在寻找适合的巢域。 3.结合过去监测数据分析，在放归区域大熊猫和羚牛尽管同域分布，但由于食性不同，对微生境选择还是有着很大差异，因此保护管理对策要有针对性。 4.“盛林1号”的放归是成功的。救护大熊猫异地放归工作应继续开展，但要改进放归后的监测技术。要改进现有对人工饲养大熊猫野化培训方法和放归方式，才能真正将人工繁殖个体放归野外。 Giant Panda (Ailuropoda melanoleuca) is an endangered species endemic to China. It was listed as National Protected I Class Species and is crowned as “National treasure” of China. The populations of Giant Panda are limited in 6 mountain system in Center-West of China, i.e. Mingshan, Mt. Qionglai, Mt. Daxiangling，Mt. Xiaoxiangling, Mt. Liangshan and Mt. Qinling. The results of the Third National Survey on Giant Panda showed that the habitats of Giant Panda is still fracted and Giant Panda population is divided into several isolated small populations. Population B from Mt. Daxiangling, Mt. Xiaoxiangling and Mt. Mingshan and Population C from Mt. Mingshan are very small with very fracted habitat and are more endangered. Several populations in those mountain systems are smaller than Minimum Viable Population of Giant Panda. It is very possible that those populations will be extinct without artificial help. The ultimate Goal of Reintroduction caged Giant Panda to wild is to increase wild population size and genetics diversity and rebuild and expand wild Giant Panda population. It is of significant to return rescued wild Giant Panda to wild and monitor their behavior before reintroduction artificial reproduced Giant Panda. It will increase our knowledge on reintroduction of Giant Panda. Aug 8th, 2005, “Shenglin 1”, a rescued wild Giant Panda was returned to Longxi-Hongkou National Nature Reservoir, which is habitat of Giant Panda Population B of Mt. Mingshan. A systematic monitor was carried out on “Shenglin 1”, and the successful return enriched our biological knowledge on Giant Panda reintroduction. It will be very help for future conservation work on reintroduce artificial reproduced Giant Panda. “Shenglin 1” was tracked with GPS collar, DNA in feces and infrared-trigged camera from Aug 2005 to Jun 2007. 1. Locomotion behavior and microsatellites comparison with Giant Panda from the 5 mountain systems indicated that “Shenglin 1” is possibly from Mt. Qionglai. 2. Habitat usage of “Shenglin 1” was studied. It was suggested that there were 3 phases after return, i.e. emergency response, preliminary stable phase and long distance locomotion, which could be a general process for other returned Giant Panda. It was indicated that there was some interaction between “Shenglin 1” and local population. “Shenglin 1” is seeking for suitable home range now. 3. Monitor data also indicated that microhabitat preference of Giant Panda and takin (Budorcas taxicolor) are different because of different diet, though they are sympatric. It was suggested that conservation management for the two species should be plan in particular. 4. The reintroduction of “Shenglin 1” is a successful case. The program of return rescued Giant Panda to other habitats is of value and should be continued. However, more improvement is needed for the monitor technique. More improvement is need for feralization and returning before we return artificial reproduced Giant Panda to wild.

Gamma decay of the lowly excited states of 189Re

189W activities were produced via the 192Os(n, α) reaction using irradiation of isotopically enriched 192Os metallic powder of ～100 mg/cm2 with 14 MeV neutrons. The X-γ and γ-γ coincidence measurements were made so as to obtain γ rays from 189W decay and its coincidence relations. A new simple decay scheme of 189W including three γ rays of 210.2, 229.6 and 260.2 keV is proposed. Two new levels of 189Re at 470.4 and 489.8 keV are assigned.

2.6 s isomer of Nd-129

Nd-129 was produced by irradiation of an enriched target of Ru-96 with a Ar-36 beam and studied by using a helium-jet fast tape transport system in combination with X-gamma and gamma-gamma coincidence measurements. A 2.6s isomer of Nd-129 was observed for the first time and tentatively proposed to be the configuration of 1/2[411].