Biomass accumulations and nutrient uptake of plants cultivated on artificial floating beds in China's rural area

Focused on water pollution in China's rural area, taking Oenanthe javanica (Oj), Gypsophila sp. (Gy), Rohdea japonica (Rj), Dracaena sanderiana (Ds), Gardenia jasminoides Var. grandiflora (Gg), Gardenia jasminoides Var. prostrata (Gp), and Salix babylonica (Sb) as research objects, this paper investigated the growth characteristics and nutrient uptake of these seven species cultivated on artificial floating beds. The results indicated that after about 130 days’ acclimation, these seven species had different growth characteristics. The survival rates of each species were close to 100%. Dry matter biomass ranged from 33.7 to 307.1 g m⁻² in the following order: Sb > Gy > Oj > Ds > Gg > Gp > Rj. There were significant linear relationships between above-water and under-water biomass (R > 0.875); thus, the above-water biomass could best reflect the under-water biomass. N and P concentrations and distribution in the root, stem and leaf were quite different both within and between the species. N and P concentrations in plant body ranged from 15.31 to 23.15 g kg⁻¹ in the relationship Oj > Ds > Gy > Gp > Sb > Rj > Gg, and from 1.07 to 1.89 g kg⁻¹ in the relationship Rj > Gp > Oj > Gg > Gy > Sb > Ds, respectively. N and P accumulations ranged from 0.51 to 4.48 g m⁻² and from 0.062 to 0.331 g m⁻², respectively, in which plant nutrient uptake ability could be placed as follows: Sb > Gy > Oj > Ds > Gp/Gg > Rj. The outcomes also indicated that there were positive and significant linear relationships between N and P accumulations and plant biomass (R > 0.964), respectively; thus, plant harvest could be a means of taking N and P out of wastewater. Seven species, especially Sb, Gy, and Oj, had an ideal effect on TN and TP removal and could be widely utilized for the treatment of wastewater in rural areas.     

Nitrogen removal in moving bed sequencing batch reactor using polyurethane foam cubes of various sizes as carrier materials

The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal.     

Selection of prey from a seagrass/mangrove environment by golden lined whiting, Sillago analis (Whitley)

Most previous studies of food selection by fishes have been conducted on visually-feeding species in relatively unstructured environments. The food selection behaviour of Sillago analis (Whitley), feeding nocturnally in a complex seagrass/mangrove environment, was assessed. Crustacean prey were relatively accessible and displayed the highest electivity values. Annelids were usually buried at least 30 mm below the substrate surface and, like potential fish prey, were either not taken or showed consistently negative electivities. Although many mollusc species were accessible, only the siphon tips of the bivalve Glauconome virens (Linnaeus) were positively selected. Results from both field and laboratory indicated that S. analis is not a strongly size-selective predator. However, in contrast to the field study, the laboratory results showed that S. analis had a strong preference for annelids [ Marphysa sanguinea (Montague)] as well as crustaceans. The food selection patterns of S. analis could not be clearly described in terms of single parameters such as prey size, prey abundance or prey energy content, which have been used in the context of optimal foraging theory and are often described as strong determinants of food selection in visual predators. Instead, this nocturnally-feeding species takes a variety of the more vulnerable prey (i.e. those which are spatially accessible, weakly motile or thinly shelled) in an apparently opportunistic fashion.     

流沙湾海草床重金属富集特征

海草床是一种重要的海洋湿地生态系统,首次研究了流沙湾海草床重金属(铜、铅、镉、锌)的富集特征,并评价其潜在生态危害.研究表明:水体和沉积物环境中的重金属含量很低,潜在生态危害轻微,但是海草床大型底栖生物(绿藻、海草、双壳类和腹足类)对这4种重金属具有富集作用,其中对镉的富集最显著.绿藻对铜、铅和锌的富集效应明显大于海草,腹足类对铜、铅和锌的富集效应明显大于双壳类;而对镉的富集效应,情况正好相反.双壳类生物体内铅和镉含量普遍超一类标准,超标程度较高.     

Toxicants inhibiting anaerobic digestion: A review

Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.     

甲烷氧化菌吸附膜反应器中环氧丙烷的连续生物转化

以流化床作为固定化体系 ,在硅藻土颗粒表面构建了混合培养的甲烷氧化细菌的吸附膜。研究发现延迟期后固定化细胞的甲烷单加氧酶活性明显增加。流化床中 90 %以上的甲烷氧化细菌以吸附形式存在。吸附膜浓度为 3.3～3.7 mgdryweightcell gDS。通过批式反应考察了丙烯 甲烷共氧化过程合成环氧丙烷的可能性。研究了甲烷对丙烯环氧化以及丙烯对甲烷氧化细菌生长的影响。通过最佳配比的混合反应气体 (methane :35 % ;propene :20% ;oxygen :45 % )连续循环通入流化床反应器中抽提产物环氧丙烷 ,克服了产物抑制。该生物反应器最初产生环氧丙烷的日产量为 110～ 150μmol d ,连续操作25d ,未观察到环氧丙烷生产能力的明显减小.     

Cell immobilization using PVA crosslinked with boric acid

A new cell immobilization technique is described in which polyvinyl alcohol is crosslinked with boric acid, with the addition of a small amount of calcium alginate. The presence of the calcium alginate improves the surface properties of the beads, preventing agglomeration. A pure culture of phenol-degrading Pseudomonas was immobilized in the PVA-alginate beads. Phenol was successfully degraded in a fluidized bed of the beads, indicating that cell viability was maintained following the immobilization procedure. The PVA-alginate beads proved to be very strong and durable, with no noticeable degradation of the beads after 2 weeks of continuous operation of the fluidized bed.     

黄渤海海草分布区日本鳗草根际微生物群落结构特征及其功能分析

日本鳗草(Zostera japonica)是亚洲特有的海草种类,具有重要生态价值。近年来,黄渤海海草分布区中的日本鳗草海草床持续退化,引起了研究人员的广泛关注。【目的】基于根际微生物的分布与日本鳗草的健康生长密切相关的设想,本文旨在探究黄渤海海草分布区日本鳗草根际细菌群落结构多样性并分析其与海草健康生长的内在联系。【方法】选取黄渤海海草分布区中东营、威海、大连3个地点的日本鳗草根际与非草区表层沉积物,采用高通量测序技术(Illumina HiSeq PE300)解析根际微生物群落特征,并结合相关环境参数分析其环境功能。【结果】日本鳗草根际表层沉积物中主要存在的细菌类群有:变形菌门(Proteobacteria)所占比例为41.1%,蓝细菌门(Cyanobacteria)占15.4%,拟杆菌门(Bacteroidetes)占12.6%,放线菌门(Actinobacteria)占9.3%。不同地点之间以及样品类型(海草床根际与非根际)之间的微生物群落存在显著差异,主要表现为根际富含硫酸盐还原菌和固氮菌。环境因素:TN (total nitrogen)、TC (total carbon)、TOC (total organic carbon)、黏土(Clay)、砷(As)与根际群落组成与分布显著相关。【结论】从功能的角度来看,不同地点、不同样品类型之间的差异物种多与硫、氮代谢相关,硫酸盐还原菌对维持日本鳗草的生态健康起关键作用;日本鳗草根际微生物群落分布与环境因子、空间分布有一定相关性。     

海草生态学研究进展

海草床生态系统是生物圈中最具生产力的水生生态系统之一,具有重要的生态系统服务功能。作者根据海草生态学及相关领域的最新研究进展,对世界范围内海草床的空间分布、海草床的生态系统服务功能以及外界因素对海草床的影响等研究进展进行了综述。海草床生态系统服务功能主要包括净化水质、护堤减灾、提供栖息地和生态系统营养循环等。对海草床影响较大的外界环境因素包括盐度、温度、营养盐、光照、其他动物摄食、人类活动和气候变化等。海草普查、海草生态功能研究,影响海草床的主要环境因素,海草修复研究等将是我国海草研究的主要方向。     

微生物参与海草床元素循环及其生态修复功能

海草是分布在全球海岸带的沉水被子植物,与周围环境共同形成的海草床生态系统是三大典型海洋生态系统之一,具有十分重要的生态功能。20世纪以来,全球海草床衰退严重,研究海草床的生态修复迫在眉睫,现有修复方法未能足够重视微生物在海草床中的重要作用。本文综合阐述了微生物在海草床生态系统有机物矿化和营养流动过程中起到的作用,分析了微生物驱动下的海草床水体与沉积物之间的元素循环,提出了人类活动引起海草床退化的原因,总结了海草床微生物的系统研究方法,并在此基础上提出从微生物生态的角度修复海草床的新思路。