Effects of temperature, algae biomass and ambient nutrient on the absorption of dissolved nitrogen and phosphate by Rhodophyte Gracilaria asiatica

Gracilaria asiatica,being highly efficient in nutrient absorption,is cultivated in sea cucumber ponds to remove nutrients such as nitrogen and phosphate.It was cultured in a laboratory simulating field conditions,and its nutrient absorption was measured to evaluate effects of environmental conditions.Ammonia nitrogen(AN),nitrate nitrogen(NN),total inorganic nitrogen(TIN),and soluble reactive phosphorus(SRP) uptake rate and removal efficiency were determined in a 4×2 factorial design experiment in water temperatures(T) at 15℃ and 25℃,algae biomass(AB) at 0.5 g/L and 1.0 g/L,total inorganic nitrogen(TIN) at 30 μmol/L and 60 μmol/L,and soluble reactive phosphorus(SRP) at 3 and 6 μmol/L.AB and ambient TIN or SRP levels significantly affected uptake rate and removal efficiency of AN,NN,TIN,and SRP(P<0.001).G.asiatica in AB of 0.5 g/L showed higher uptake rate and lower removal efficiency relative to that with AB of 1.0 g/L.Nitrogen and phosphorus uptake rate rose with increasing ambient nutrient concentrations;nutrient removal efficiency decreased at higher environmental nutrient concentrations.The algae preferred to absorb AN to NN.Uptake rates of AN,NN,and SRP were significantly affected by temperature(P<0.001);uptake rate was higher for the 25℃ group than for the 15℃ group at the initial experiment stage.Only the removal efficiency of AN and SRP showed a significant difference between the two temperature groups(P<0.01).The four factors had significant interactive effects on absorption of N and P,implying that G.asiatica has great bioremedial potential in sea cucumber culture ponds.     

Impact of water source dynamics on dissolved reactive phosphorus loadings in heterogenous karst agroecosystems with phosphatic limestones

Karst landscapes underlain with phosphatic limestones are now recognized to be an important contributor of fluvial phosphorus (P) to coastal waters. Specifically, karst agroecosystems may be a hotspot for dissolved reactive P (DRP) due to chronic over-application of organic and inorganic fertilizers that create legacy P accumulation in surface soils. Nevertheless, few studies have assessed the hydrologic controls on DRP transport in these systems at the watershed scale, which is the focus of this study. We analysed soil moisture, soil water extractable P, and storm event hydrologic and water quality data from a small heterogenous karst watershed (10.7 km²) in the Inner-Bluegrass Region of Central Kentucky, USA. Four storm events were sampled in winter, 2020 and were analysed for flow pathways using hydrograph recession analysis and water source connectivity using a tracer-based unmixing model. Based on hydrograph separation results, multiple linear regression analysis was performed to assess drivers of DRP concentrations and loadings. Soil water extractable P results showed stark vertical gradients with greater concentrations at both the surface and deeper soil zones, and minimum concentrations in the root zone. Results for the storm event analysis showed that water source connectivity provided superior prediction of DRP concentrations over the flow pathway analysis, which reflected the heterogeneity of karst maturity masking intermediate flow pathways. Findings from the MLR and loading analysis suggest waters sourced from the soil/epikarst produced significantly higher loadings compared with phreatic and precipitation water source in the three largest events, although concentrations fell between the phreatic (low) and precipitation (high) sources. Findings highlight variable activation of matrix-macropore exchange at different depths throughout the event. Collectively these results suggest existing models and approaches to assess karst hydrology need revision to improve management strategies in this critical landscape.     

感应测井的复视电导率响应特性

感应测井的实部视电导率 (也叫R信号 )与虚部视电导率 (也叫X信号 )构成复视电导率。在给出这两种视电导率定义之后 ,利用解析解和数值模式匹配法计算了几种地层的感应测井的两种视电导率响应曲线。得出的主要结论有 :虚部视电导率对实部视电导率起一定的趋肤效应补偿作用 ;虚部视电导率的探测深度大于实部视电导率 ;井眼对实部视电导率的影响较大 ;实部视电导率的纵向分辨率优于虚部视电导率 ;当线圈系穿过的地层磁导率有变化时 ,虚部视电导率将有较大的波动。     

Burial Records of Reactive Iron in Cretaceous Black Shales and Oceanic Red Beds from Southern Tibet

One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides （largely hematite）, which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.     

陕南勉宁略地区铜厂铜矿找矿标志探讨

本文对铜矿铜矿中石英包裹体特征、黄铁矿热电性和卤素分布特征进行了研究,结果表明,在矿区Ｆ的高度富集区是铜成矿的有利地段,且越靠近矿体,其中黄铁的热电系数负值越大,石英中包裹体数量越多、含盐度越高,矿化越好,因此,该矿区可以加强包裹体、黄铁生和卤素分布特征研究并指导找矿对矿化评价。     

Antioxidant efficacy of extracts from a variety of seaweeds in a cellular system

As a part of an ongoing search for antioxidants frodm marine sources, antioxidant activities of 24 kinds of seaweeds (4 green algae, 8 brown algae, and 12 red algae) were investigated. The seaweeds were extracted by acetone/ dichloromethane and methanol, respectively. The antioxidant properties of both extracts were evaluated using four different activity tests, including degree of occurrence of intracellular reactive oxygen species (ROS), NO, lipid peroxidation, and GSH (glutathione) in mouse macrophage Raw 264.7 cells. The levels of intracellular reactive oxygen species (ROS) and GSH were measured using 2’,7’-dichlorofluorescin diacetate (DCF-DA) and monobromobimane as fluorescence probe, respectively. Moreover, the generation of NO and lipid peroxidation products were determined by each method based on the Griess reaction and TBARS assay. Solvent extracts from seaweeds such asScytosiphon lomentaria, Prionitis cornea, Laruencia okamurae,Callophyllis japonica, Sargassum horneri, Dictyopteris divaricat a,Lomentaria catenata, Corallina confuse, Ishige okamurae, andAhnfeltiopsis flabelliformi exhibited high antioxidant activities in cellular oxidizing systems.     

改性粘土絮凝法对小球藻(Chlorella vulgaris)生理生化性质的影响

改性粘土治理赤潮生物的主要原理是絮凝作用,但水体中未被去除的微藻对改性粘土有怎样的生理生化响应尚不清楚。本文以小球藻(Chlorella vulgaris)为模式生物,考察了改性粘土絮凝后水体中残余小球藻生理生化性质的变化情况。研究发现,经改性粘土或原土絮凝后,残余小球藻的生长受到了明显抑制,其丙二醛(malondialdehyde,MDA)含量迅速上升,改性粘土组的MDA含量高于原土组。除了原土组过氧化氢酶(catalase,CAT)活性相比对照组没有明显变化外,改性粘土组和原土组超氧化物歧化酶(superoxide dismutase,SOD)、CAT、抗坏血酸过氧化物酶(ascorbate peroxidase,APX)和谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-PX)等酶活,均呈现先上升后下降、并稳定在较高水平的变化趋势。原土组各酶活普遍低于改性粘土组,但GSH-PX活性则相反。结果表明,改性粘土不仅能高效去除水体中的小球藻,而且能够刺激残余的藻细胞积累较多的O2-·和H2O2,从而对藻细胞造成过氧化伤害,抑制未被去除部分海洋微藻的正常生长。     

脱落酸介导的逆境响应信号传导机制及在藻类中的分布与功能研究

植物激素是一类由植物合成的痕量有机物质,调控着植物的生长发育及对环境的适应。藻类属低级植物类群,且具有与高等植物类似的大多数激素类型,相对而言,藻类激素含量更少,却发挥着更高效的生理活性。无论在藻类,还是高等陆地植物,胁迫响应一直是研究十分活跃的领域。其中脱落酸(ABA)作为应激激素,所起的调节作用已得到人们的共识。本文总结了近些年关于ABA在藻类中的分布,ABA对抗氧化酶系的调控,ABA信号传导路径在陆地植物中的发现与代谢机制,以及利用蛋白质分子系统学对ABA信号传导途径的起源与进化的分析。在此基础上,提出未来藻类ABA参与的抗逆代谢调控研究应着重从潮间带海藻出发,参考陆地植物研究的成果,应用生物信息学结合生物化学等的手段,进行相关机制的探索。     

Plume Behavior for Petroleum Hydrocarbon in a Tropical Sand Tank: Laboratory Experiments and Scenario-Specific Modelling

Numerical simulations were performed to assess the reactive transport and natural attenuation of gasoline fuel components in a 3-D sand tank model. The conceptual model includes a residual gasoline source that dissolves into the 3-D aquifer. The analysis reveals high to very high correlation between the observed and simulated values (average R² = 0.97). A retardation factor R = 1.5, and first-order decay rate of 0.0002/day were obtained from the model calibration for BTEX.

The results are highly relevant in the light of the increasing awareness of the precarious trend of lack of monitoring and remedial feasibility data for the subsoil environment in the thousands of gasoline fuel stations, and petroleum storage/distribution underground infrastructure and the riverbeds of inland waterways in Nigeria.

The biodegradation rate was the most sensitive model parameter, with about 82% increase in BTEX maximum plume concentration, for the zero biodegradation scenario.     

流式细胞术检测虾类血细胞活性氧含量方法的建立

建立和优化了流式细胞术检测虾类血细胞活性氧含量的方法。以2′,7′-二氢二氯荧光黄双乙酸钠(DCFH-DA)为ROS特异探针,以斑节对虾(Penaeus monodon)血细胞为材料,用流式细胞仪检测不同染料浓度和不同染料孵育时间下血细胞的荧光强度、细胞形态特征和细胞活性的变化。结果表明,利用FCM检测虾类血细胞ROS含量的适宜的染料浓度和最佳的孵育时间分别为10μmol/L和30 min。