Stabilisation/solidification and bioaugmentation treatment of petroleum drill cuttings

Petroleum drill cuttings are usually treated by techniques suitable for particular contaminant groups. The significance of this study consists in the development of a treatment technology that can simultaneously handle the hydrocarbon and metal constituents of drill cuttings. Bioaugmentation is combined with stabilisation/solidification (S/S), within S/S monoliths and in granulated S/S monoliths. Portland cement was used for S/S treatment at 30% binder dosage. Bioaugmentation treatment involved two bacterial densities of a mixed culture bio-preparation. The effects of inclusion of compost, fertiliser and activated carbon were also evaluated. After 28 days, the combined S/S and bioaugmentation treatments recorded up to 15% higher total petroleum hydrocarbon (TPH) loss than control S/S treatment without bioaugmentation. Embedding fertiliser, activated carbon and higher bacterial density within S/S monoliths resulted in the highest (99%) TPH reduction but higher concentrations of metals. The addition of compost and lower bacterial density to granulated S/S monoliths led to similar (98%) TPH degradation and lower amounts of metals. The results suggest that with better mixture optimisation, combining S/S and bioaugmentation could engender more sustainable treatment of drill cuttings.     

Closely related thyasirid bivalves associate with multiple symbiont phylotypes

Species of thyasirid bivalves are considered to be representative of early stages of chemosymbiosis, given that bacterial symbionts occur outside gill epithelial cells, vary among species in their abundance and nutritional importance, and are environmentally acquired. For these reasons, assessing the extent of host–symbiont specificity in thyasirids could provide valuable information on the evolution of chemosymbiosis. We show that individuals of two closely related and sympatric Thyasira cf. gouldi operational taxonomic units collected from three sites in a fjord in Newfoundland, Canada, associate with one of three distinct, closely related symbiont phylotypes. While associations show some site‐specificity, there is flexibility in host–symbiont pairings within the fjord, further supporting an early and relatively unspecific stage of chemosymbiosis in this family. Morphologic differences observed both within and among symbiont phylotypes suggest physiologic variation, possibly induced by small‐scale differences in sedimentary conditions.     

A seasonal comparison of prokaryote numbers,biomass and heterotrophic productivity in waters of the KwaZulu-Natal Bight,South Africa

The KwaZulu-Natal Bight is a shallow indentation of the eastern seaboard of South Africa, characterised by a narrow (45 km wide) extension of the continental shelf, with a shelf break at about 100 m. It has a complex hydrography: the waters of the bight are derived from the fast-flowing, southward-trending Agulhas Current, which is fed mostly by the tropical and subtropical surface waters of the South-West Indian Ocean subgyre, which are generally oligotrophic in nature, notably depleted in reduced nitrogen and phosphate except at river mouths and during periodic upwelling of deeper nutrient-rich water. Despite this, the bight is believed to be relatively productive, and it is suggested that efficient nutrient recycling by prokaryotes may sustain primary productivity efficiently, even in the absence of new nutrient inputs. Here we have measured bacterial numbers, biomass and heterotrophic productivity during summer and winter in conjunction with phytoplankton standing stock and factors that influence it. Bacterial distribution closely matched phytoplankton distribution in surface waters, and was highest close to the coast. Bacterial standing stocks were similar to those of oligotrophic systems elsewhere (0.5–5.0 × 10⁵ cells ml^–1; 1 × 10^–8 to 1.25 × 10^–7 g C ml^–1) and increased in association with the development of phytoplankton blooms offshore and with inputs of allochthonous material by rivers at the coast. Heterotrophic productivity in summer was lowest in the far south and north of the bight (0.5 × 10^–10 g C ml^–1 h^–1) but higher close to the shore, over shallow banks, and in association with increased phytoplankton abundance over the midshelf (1.0–3.5 × 10^–9 g C ml^–1 h^–1). There were marked seasonal differences with lower bacterial standing stocks (5 × 10⁴ to 2 × 10⁵ cells ml^–1; 4–5 × 10^–9 to 1–2 × 10^–8 g C ml^–1) and very low bacterial productivity (4 × 10^–11 to 1 × 10^–10 g C ml^–1 h^–1) in winter, probably resulting from lowered rates of primary productivity and dissolved organic matter release as well as reduced riverine allochthonous inputs during the winter drought.     

季节性低温胁迫下陇东黄土高原油污土壤环境因子对耐冷混合菌场地生态修复的响应

为了揭示季节性低温胁迫下陇东黄土高原油污土壤环境因子对耐冷混合菌场地生态修复的响应机制,利用自主筛选构建的耐冷石油降解混合菌在甘肃省庆阳市庆城县马岭镇长庆油田陇东油泥处理站开展了为期7个月的场地修复实验,采用常规方法测定了不同季节土壤理化特性、酶活性和微生物群落特性等环境指标。结果表明：（1）在季节性低温胁迫下（9-11月）M2组（耐冷混合菌处理组）月平均降解率明显增加（P<0.01）,JZJ+M1组（金盏菊联合常温混合菌处理组）和M2组累计TPH降解率分别为15.37%±3.51%和28.64%±4.12%。（2）M2组土壤脱氢酶和多酚氧化酶在低温季节（LT）活性最高,且温度和处理存在显著交互作用（P<0.01）。在土壤营养元素方面,无论何种处理方式（JZJ+M1和M2）二者含量均为RT（常温季节）高于LT（P<0.05）,同时明显高于CK组（P<0.05）。（3）M2组土壤微生物群落Shannon-Wiener指数和均匀度指数在LT高于RT（P<0.05）。（4）NMDS和Pearson相关性分析结果显示,M2组在低温季节具有较高TPH降解率主要与土壤多酚氧化酶、脱氢酶、单月TPH降解率（μ2）和Shannon-Wiener指数有关,且均呈极显著正相关关系。通过分析环境因子的季节响应,优化场地修复在低温环境的降解条件、加速低温期石油烃降解速率,以期为陇东地区低温耐冷混合菌场地生态修复技术的推广应用提供参考和基础数据资料。     

硫介导细菌还原载砷铁矿对砷迁移转化的影响

硫在铁和砷的生物地球化学循环中发挥着重要作用,但地下水系统中硫循环的中间产物S(0)对细菌转化铁和砷的影响尚不清楚.采用室内模拟实验,研究硫参与下细菌D2201对液相和载砷针铁矿中Fe(III)和As(V)的还原作用.结果表明:细菌D2201具有很强的铁还原能力,可以将液相中74%的Fe(III)还原;加入硫后,细菌还原S(0)产生的S(-II)使铁还原率提高到94%.但是,硫没有明显影响细菌对砷的还原.在实验初期,细菌明显加速了载砷针铁矿的还原,最终还原释放到液相中的Fe(II)浓度为32.12 μmol/L;硫的加入增强了细菌对载砷针铁矿的还原,还原溶解的Fe(II)增加至284.13 μmol/L,同时,砷的释放量也增加了1.6倍.这些结果表明硫显著促进了细菌对针铁矿的还原溶解并加速砷的释放.XRD和SEM-EDS结果显示,细菌还原针铁矿但不改变其矿相,而硫的加入也仅使矿物发生一定程度的团聚,并没有使其转变为其他矿物,也未导致砷的再吸附.      

Molecular phylogenetic analysis of sulfate-reducing bacteria from deep sediment layers of the tropical West Pacific warm pool

1IntroductionThe tropical West Pacific warm pool(TWP-WP),which spans an area roughly between10°Nto10°S of the equator from Indonesia to the dateline,has the world’s warmest sea surface temperature ofbeing greater than29℃.With the increase of recog-niz…     

毛乌素沙地锦鸡儿（Caragana）根系微域细菌群落多样性特征

基于16S rRNA高通量基因测序技术,对毛乌素沙地小叶锦鸡儿（Caragana microphylla)、柠条锦鸡儿（Caragana korshinskii）根系微域（即根系、根际土、根区土、灌丛间空白土）间的细菌群落多样性和结构差异性进行表征。本研究对各根系微域间细菌群落的Alpha多样性指数进行了单因素方差分析以及基于OTU水平的PCA分析,探究其在根系微域间Alpha和Beta多样性的层级变化,证实了有关植物根系微域生态位分化的报道,并发现锦鸡儿属植物根系微域间细菌群落的多样性和结构组成随着4个微域类型由外及内呈现出显著的层级差异性（P<0.05）。通过对优势细菌群组的结构组成分析,发现锦鸡儿属植物对特定细菌群组具有显著的向根系内筛选富集的作用（P<0.05）。这种植物通过根系微域对特定细菌群组的逐级筛选富集作用,是导致锦鸡儿属植物灌丛下不同生态位间细菌群落结构和组成发生层级变异的主要原因。     

平端深海偏顶蛤(Gigantidas platifrons)实验室蓄养过程鳃部含菌上皮细胞超微结构动态变化研究

平端深海偏顶蛤(Gigantidasplatifrons)是南海台西南冷泉区的典型优势物种,鳃丝上皮细胞内共生大量甲烷氧化菌,通过甲烷有氧氧化合成有机物为共生体系提供物质能量,是平端深海偏顶蛤赖以生存的重要能量来源器官,溶酶体在共生体系的营养互作和稳态维持中可能发挥重要作用,本研究使用电镜技术观测了常压培养过程中(0d,30d,90d)平端深海偏顶蛤共生体系中共生菌和溶酶体的动态变化,通过鳃上皮含菌细胞超显微结构的变化研究常压培养对深海共生体系的影响,并探讨溶酶体在宿主—共生菌营养传递和共生菌群稳态维持中的关键作用。研究发现,在原位状态样品中(0d)共生菌和溶酶体呈极化分布,细胞结构完整清晰;蓄养30d后,含菌细胞出现明显破碎,共生菌数量大幅降低,溶酶体数量、范围和消化程度大幅增加,对细胞顶端的甲烷氧化菌进行分解;而90d后,共生菌在溶酶体的作用下消失殆尽,鳃部有明显细胞脱落后留下的坑洞,细胞呈现空泡状,无法明确区分各种细胞组分。上述结果展示了长期常压蓄养过程中鳃上皮含菌细胞中溶酶体与甲烷氧化菌的动态变化,推测当共生菌丢失后溶酶体也同步降低活跃度,平端深海偏顶蛤在共生互作中通过溶酶体主导消化和调控共生菌。     

用于海洋沉积物中厌氧氨氧化细菌分子生态学研究的引物比较

为比较厌氧氨氧化细菌16SrRNA基因的2对特异性引物(Amx368F/Amx820R、Brod541F/Amx820R)在其分子生态学研究方面的优点与不足,本研究采用高通量测序和qPCR技术对长江口及其邻近海域沉积物中厌氧氨氧化细菌细菌的群落组成、多样性和丰度进行比较分析,结果表明,引物Amx368F/Amx820R特异性较高,能够较为完整地反映沉积物中厌氧氨氧化细菌的多样性信息,且其覆盖的厌氧氨氧化细菌丰度与功能基因hzo丰度正相关(P<0.01);而引物Brod541F/Amx820R特异性较低,覆盖部分厌氧氨氧化细菌及其他多个门的细菌,其量化的厌氧氨氧化细菌与功能基因hzo丰度无明显相关关系(P>0.05)。因此,引物Amx368F/Amx820R能够更加真实地反映厌氧氨氧化细菌在海洋沉积物中的群落特征,在其分子生态学研究中更具优势。     

Contribution of trimethylamine N-oxide on the growth and pressure tolerance of deep-sea bacteria

Trimethylamine N-oxide(TMAO) is widely dispersed in marine environments and plays an important role in the biogeochemical cycle of nitrogen. Diverse marine bacteria utilize TMAO as carbon and nitrogen sources or as electron acceptor in anaerobic respiration. Alteration of respiratory component according to the pressure is a common trait of deep-sea bacteria. Deep-sea bacteria from dif ferent genera harbor high hydrostatic pressure(HHP) inducible TMAO reductases that are assumed to be constitutively expressed in the deep-sea piezosphere and facilitating quick reaction to TMAO released from ?sh which is a potential nutrient for bacterial growth. However, whether deep-sea bacteria universally employ this strategy remains unknown. In this study, 237 bacterial strains affliated to 23 genera of Proteobacteria,Bacteroidetes, Firmicutes and Actinobacteria were isolated from seawater, sediment or amphipods collected at dif ferent depths. The pressure tolerance and the utilization of TMAO were examined in 74 strains. The results demonstrated no apparent correlation between the depth where the bacteria inhabit and their pressure tolerance, regarding to our samples. Several deep-sea strains from the genera of Alteromonas, Halomonas,Marinobacter, Photobacterium, and Vibrio showed capacity of TMAO utilization, but none of the isolated Acinebacter, Bacillus, Brevundimonas, Muricauda, Novosphingobium, Rheinheimera, Sphingobium and Stenotrophomonas did, indicating the utilization of TMAO is a species-speci?c feature. Furthermore, we noticed that the ability of TMAO utilization varied among strains of the same species. TMAO has greater impact on the growth of deep-sea isolates of Vibrio neocaledonicus than shallow-water isolates. Taken together, the results describe for the ?rst time the TMAO utilization in deep-sea bacterial strains, and expand our understanding of the physiological characteristic of marine bacteria.