Growth dynamics of the seagrass <Emphasis Type="Italic">Halophila nipponica</Emphasis>, recently discovered in temperate coastal waters of the Korean peninsula

Seagrass species in the genus Halophila are usually distributed in tropical or subtropical areas, but a Halophila species identified as H. nipponica was first observed in temperate coastal regions of Korea in 2007. Since this species mainly occurs in warm temperate regions influenced by warm currents, we hypothesized that H. nipponica may exhibit different growth patterns from those of other temperate seagrass species in Korea, instead showing similar growth dynamics to tropical/subtropical species. The growth and morphology of H. nipponica in relation to coincident measurements of environmental factors were investigated from July 2008 to September 2009 to examine the growth dynamics of this species. Water temperature at the study site ranged from 9.7°C in January to 25.1°C in August. Shoot density, biomass, and productivity exhibited significant seasonal variation, increasing during summer and decreasing during winter. Productivity was severely restricted to nearly ceasing at water temperatures less than 15°C, and winter minimum growth lasted until May. The optimal temperature for H. nipponica growth was approximately 25°C, which was the maximum water temperature at the study site, and no growth reduction in high summer water temperature was observed. Thus, H. nipponica on the temperate coast of Korea exhibited a distinctly different growth pattern from those of temperate seagrass species in Korea, which have shown great reductions in growth at water temperatures higher than 20°C. Higher below- to above-ground ratio and leaf burial into sediments with shorter leaf petioles during winter might be overwintering strategies in this species. The growth patterns of H. nipponica at the study site imply that this species still possess the tropical characteristics of the genus Halophila.     

基于离散元法的能源管传热过程模拟

采用自主研发的离散元软件MatDEM,依据能源管桩的现场热响应试验,提出了能源桩离散元数值模拟的建模方法,对能源管桩的热响应试验过程进行了模拟研究,得到了桩周土体的位移分布,桩芯和桩周土体的温度分布,通过与现场实测数据的对比,验证了利用离散元法研究能源桩换热性能的有效性,该方法在研究能源桩与土体的热-力学行为特征方面具有广阔的应用前景。     

Feasibility of weeds-based compost-cultivated Agaricus bisporus北大核心CSCD

Making full use of local weed resources to produce Agaricus bisporus is of great importance in reducing production costs and protecting the environment. In this paper, three trial experiments were conducted on the basis of weed diversity investigation around the Miyun Reservoir and the adjustment of formulation and technology in the industrial production of A. bisporus. Compost samples from different phases of the composting process and at various cultivation stages were collected for the determination of their physical-chemical properties, lignocellulose content, lignocellulolytic enzyme activities, and bacterial communities enrichment by 16S rRNA gene sequencing. The yield of mushrooms in each different trial was also calculated. The results showed several types of reservoir weeds with high, thick and hard stems. The saturated moisture of weeds was 76.78% after baling. The water content, carbon content, and C/N ratio of the samples decreased gradually during composting, but had little change during cultivation. The nitrogen content decreased at the end of phase I and increased at the end of phase II. During composting, the loss rates of hemicellulose and cellulose were both between 40% and 60%, and the loss rate of lignin was between 20% and 30%. During cultivation, instead, the loss rate of lignin was between 16% and 21%. The changes in the content of cellulose and hemicellulose of compost were consistent with that of the activity of the related degradation enzymes. A total of 432 595 valid sequences were obtained by Illumina sequencing for the samples derived from the three composting trials, and the average length of the sequences was 441 bp. Taxonomic analysis showed that the dominant bacteria were Prevotella (phylum Bacteroidetes), Bacillus (phylum Firmicutes), Thermus, Truepera, and Caldicoprobacter (phylum Deinococcus-Thermus), Thermopolyspora (phylum Actinobacteria), and Pseudoxanthomonas (phylum Proteobacteria). The yield of the three trials was in the range of 17.1-19.7 kg/m2. It is thus feasible to use reservoir weeds compost instead of wheat straw compost for the cultivation of A. bisporus. © 2018 Science Press. All rights reserved.     

矿化垃圾生物反应床处理印染废水的工艺参数优化及优势菌群

为了探讨矿化垃圾再利用于印染废水处理的可行性,研究了矿化垃圾生化反应床处理模拟印染废水的工艺参数,进行了优势菌群的镜检和提取、培养,实验结果表明,适宜的工艺运行参数如下为水力停留时间12~24 h,水力负荷100~140 L/(m3·d),COD污染负荷240~360 g/(m3·d),布水周期为24 h条件下的进水历时为6 h;适宜的工艺运行参数条件下,矿化垃圾生化反应床对模拟印染废水的COD去除率97%以上,总磷去除率95%以上,氨氮的去除率在98%以上;处理模拟印染废水的矿化垃圾生化反应床内的微生物群落以球菌为主,该菌体对模拟印染废水具有良好的专性降解作用。研究结果将对矿化垃圾的再利用和印染废水的处理提供一定的技术参考。     

饮用水生物处理中微生物量和活性的测定方法

微生物量和微生物活性是饮用水生物处理工艺设计与运行的重要参数。总结论述了适用于表示饮用水生物处理过程生物膜中微生物数量和活性的几种主要指标的测定方法。     

Production dynamics of the eelgrass, <Emphasis Type="Italic">Zostera marina</Emphasis> in two bay systems on the south coast of the Korean peninsula

Production dynamics of eelgrass, Zostera marina was examined in two bay systems (Koje Bay and Kosung Bay) on the south coast of the Korean peninsula, where few seagrass studies have been conducted. Dramatically reduced eelgrass biomass and growth have been observed during summer period on the coast of Korea, and we hypothesized that the summer growth reduction is due to increased water temperature and/or reduced light and nutrient availabilities. Shoot density, biomass, morphological characteristics, leaf productivities, and tissue nutrient content of eelgrass were measured monthly from June 2001 to April 2003. Water column and sediment nutrient concentrations were also measured monthly, and water temperature and underwater irradiance were monitored continuously at seagrass canopy level. Eelgrass shoot density, biomass, and leaf productivities exhibited clear seasonal variations, which were strongly correlated with water temperature. Optimal water temperature for eelgrass growth in the present study sites was about 15–20°C during spring period, and eelgrass growths were inhibited at the water temperature above 20°C during summer. Daily maximum underwater photon flux density in the study sites was usually much higher than the light saturation point of Z. marina previously reported. Densities of each terminal, lateral, and reproductive shoot showed their unique seasonal peak. Seasonal trends of shoot densities suggest that new eelgrass shoots were created through formation of lateral shoots during spring and a part of the vegetative shoots was transformed into flowering shoots from March. Senescent reproductive shoots were detached around June, and contributed to reductions of shoot density and biomass during summer period. Ambient nutrient level appeared to provide an adequate reserve of nutrient for eelgrass growth throughout the experimental period. The relationships between eelgrass growth and water temperature suggested that rapid reductions of eelgrass biomass and growth during summer period on the south coast of the Korean peninsula were caused by high temperature inhibition effects on eelgrass growth during this season.     

Antibiotic exposure and potential risk of depression in the Chinese elderly: a biomonitoring-based population study

Environmental Science and Pollution Research - To examine the associations between urinary antibiotics from various sources and depression in the elderly using the biomonitoring method. In the...     

Nutritional and related experiments on laboratory maintenance of three species of symbiont-bearing,large foraminifera

Factors were examined that affect survival and growth of two common species of large foraminifera from the Red Sea,Amphisorus hemprichii Ehrenberg andAmphistegina lobifera Larsen, 1976. The former is host for dinoflagellate and the latter for diatom zooxanthellae. Experimental conditions were modeled on conditions at 25 m during spring at Wadi Taba, Gulf of Elat, Israel, the season and site where the experimental organisms were collected between 1983 and 1988. The two species responded quite differently in nutritional experiments.A. hemprichii grew, on average, 0.270 mm in diameter in 3 mo on a diet ofNitzschia subcommunis Hustedt,Chlorella sp. (clone AT) orCylindrotheca closterium Rabenhorst isolated from their native habitat. Unfed controls did not grow. In contrast, unfed populations ofA. lobifera grew as well or better than those that were fed unialgal diets. Growth of both species was enhanced on particular mixed algal diets. Both species required photosynthetically active symbionts. Even when fed weekly and supplied with nutrients, neither species survived in the dark. All individuals ofA. hemprichii died after 8 wk incubation in the dark;A. lobifera survived longer, but all were dead by 13 wk. The highest growth rate ofA. hemprichii (0.037 mm wk^–1) was obtained when they were fed, the medium was enriched, and the medium was changed weekly. All other conditions being the same, growth rate dropped to 0.009 mm wk^–1 when the medium was changed every 3 wk. In contrast,A. lobifera grew fastest when the medium was changed every 3 wk. Food or enrichment with nitrate or phosphate did not stimulate growth (0.03 mm wk^–1) over that of the controls. Specimens ofMarginopora kudakajimensis Gudmundsson from Japan, another dinoflagellate-bearing species, were also tested. They grew best (0.02 mm wk^–1) when cultured in light, in media enriched with nitrate and phosphate changed weekly, and fed. All three species withdrew nitrate and phosphate from the medium in chemostat experiments.     

Degradation of trichloroethylene by photocatalysis in an internally circulating slurry bubble column reactor

The effects of initial trichloroethylene (TCE) concentration, recirculating liquid flow rate and gas velocity on photodegradation of TCE have been determined in an internally circulating slurry bubble column reactor (0.15m-ID x 0.85 m-high). Titanium dioxide (TiO2) powder was employed as a photocatalyst and the optimum loading of TiO2 in the present system is found to be approximately 0.2 wt%. The stripping fraction of TCE by air flow increases but photodegradation fraction of TCE decreases with increasing the initial TCE concentration, recirculating liquid flow rate and gas velocity. The average removal efficiency of TCE is found to be approximately 97% in an internally circulating slurry bubble column reactor.     

Echocardiographic diagnosis of fetal marfan syndrome at 34 weeks' gestation

Fetal echocardiography was performed during the third trimester in a normal primigravida. The fetal heart was severely affected with the typical cardiac manifestations of Marfan syndrome. The medical history of the father was investigated and a mild form of the syndrome was diagnosed. The neonate died at 2 months of age of congestive heart failure.