Co-Production of Lipids,Eicosapentaenoic Acid,Fucoxanthin, and Chrysolaminarin by Phaeodactylum tricornutum Cultured in a Flat-Plate Photobioreactor Under Varying Nitrogen Conditions

The marine diatom Phaeodactylum tricornutum is a polymorphological, ecologically significant, and well-studied model of unicellular microalga. This diatom can accumulate diverse important metabolites. Herein, we cultured P. tricornutum in an internally installed tie-piece flat-plate photobioreactor under 14.5 m mol L~(-1)(high nitrogen, HN) and 2.9 m mol L~(-1)(low nitrogen, LN) of KNO_3 and assessed its time-resolved changes in biochemical compositions. The results showed that HN was inductive to accumulate high biomass(4.1 g L~(-1)). However, the LN condition could accelerate lipid accumulation in P. tricornutum. The maximum total lipid(TL) content under LN was up to 42.5% of biomass on day 12. Finally, neutral lipids(NLs) were 63.8% and 75.7% of TLs under HN and LN, respectively. The content of EPA ranged from 2.3% to 1.5% of dry weight during the growth period under the two culture conditions. Peak volumetric lipid productivity of 128.4 mg L~(-1)d~(-1) was achieved in the HN group(on day 9). The highest volumetric productivity values of EPA, chrysolaminarin, and fucoxanthin were obtained in the exponential phase(on day 6) under HN, which were 9.6, 93.6, and 4.7 mg L~(-1)d~(-1), respectively. In conclusion, extractable amounts of lipids, EPA, fucoxanthin, and chrysolaminarin could be obtained from P. tricornutum by regulating the culture conditions.     

方斑东风螺两种养殖模式的比较

在室内水泥池,利用沙层自净养殖模式和直接铺沙养殖模式对不同规格的方斑东风螺(Babylonia areolataLink)进行了高密度养殖的研究。结果表明,沙层自净养殖模式养殖小螺、中螺、大螺组日均增重分别为0.031、0.088、0.098 g/d,沙层NH4+-N最高含量w分别为1.3、2.1、3.1 mg/L,H2S最高含量w分别为0.03、0.07、0.14mg/L,各规格组东风螺保持正常生长和活动,成活率92.9%以上;直接铺沙养殖模式养殖小螺、中螺、大螺日均增重分别为:0.023、0.051、0.068 g/d,成活率分别为95.2%、86.7%、84.9%,沙层NH4+-N最高含量w达到13.7mg/L,H2S最高含量w达到0.47 mg/L,沙层底质恶化,东风螺活动异常、不摄食。可见,沙层自净养殖模式对方斑东风螺的生长、成活率、沙层水质控制效果显著,在一定程度上克服了直接铺沙养殖底质恶化问题。     

蒋庄煤矿16煤层矿井涌水量预计探讨

蒋庄煤矿的主采煤层将由开采3煤层逐渐变为16煤层。为了合理设置和调整矿井排水系统,更好地开展16煤层矿井防治水工作,尽可能准确地预计矿井涌水量。矿井16煤层已开采了多年,其矿井涌水规律需要根据近几年的资料进行总结和研究,对涌水量进行预计。简要分析了蒋庄煤矿矿井水文地质条件,结合矿井实际,对16煤层充水因素进行了分析,确定开采16煤层主要充水水源为十下灰含水层。在此基础上对16煤层涌水量进行了预计,并对预计结果进行了评价。该文分别采用大井法、比拟法和趋势线预测法等3种方法对矿井涌水量进行了预计,其中对传统的大井法进行了改进,并创造性地运用了趋势线预测法,并对各种方法的可靠程度进行了评价,对各种方法预计结果进行比较,在此基础上确定预计的矿井涌水量,从而使得预计的结果更加科学、合理,为下一步矿井防治水工作提供了可靠的依据。     

Influence of dissolved oxygen on the protectiveness and morphological characteristics of calcareous deposits with galvanostatic polarization

The influence of dissolved oxygen on calcareous deposits formed under galvanostatic polarization mode was studied.When the dissolved oxygen concentration was less than 7 mg L~(-1),the cathodic protection potential showed a plateau at the initial polarization,and then quickly shifted negatively.While the dissolved oxygen was more than 9 mg L~(-1),the potential shifted negatively in a linear form.After 168 h of polarization,the final protection potential shifted negatively with the decreasing dissolved oxygen concentration.The deposition progress was monitored by electrochemical impedance spectroscopy,and only one single loop was found in Nyquist diagram,indicating deposits of ineffective protectiveness precipitation under the experimental conditions.The protection factor of deposits increased with the decreasing dissolved oxygen concentration which was detected by linear polarization resistance technique.The cathodic electrochemical reaction could change very shortly from oxygen reduction to hydrogen evolution after cathodic protection under very low dissolved oxygen concentration,such as 1 mg L~(-1),resulting in the hydrogen bubbling from the metallic surface and the decrease of deposits protection factor.Observation by scanning electron microscopy and X-ray diffraction analysis demonstrated that the deposits were mainly of calcite under the experimental conditions,and that dissolved oxygen had no effect on the crystalline types of calcium carbonate.     

Isolation and Neuroprotective Activity of Phenolic Derivatives from the Marine-Derived Fungus Penicillium janthinellum

A new phenolic compound, 6-(2-acetyl-3,5-dihydroxybenzyl)-4-hydroxy-3-methyl-2H-pyran-2-one(1), along with other six known phenolic derivatives(2-7), were isolated from the mangrove rhizosphere fungus Penicillium janthinellum HK1-6 cultured in potato dextrose broth medium containing 30 g L~(-1) of natural sea salt. The structure of the new compound(1) was elucidated by comprehensive analysis of spectroscopic data including 1D and 2D NMR spectra. The proposed biosynthetic pathway of compound 1 was also studied in this research. Interestingly, a brominated phenolic derivative, aryl bromide(compound 8), was obtained from this fungal strain cultured in medium containing 30 g L~(-1) of NaBr instead of natural sea salt. Compound 8 is proposed as a new natural product and formed through bromination of compound 7 when the fungus was cultured with NaBr. The neuroprotective effect of compound 1 on oxygen-glucose deprivation(OGD)-induced injury was investigated in rat spinal cord astrocytes. MTT assay demonstrated that compound 1 can attenuate OGD-induced cell viability loss in rat spinal cord astrocytes.     

The upper mixed layer during coastal upwelling events on the northern portugal shelf

The upper mixed layer (UML) depth obtained from temperature is very close to that from density:the maximum is about 15m. This indicates that temperature is a good indicator of mixed layer during measurements. When the surface heat flux is balanced by a cross-shore heat flux, the surface mixed layer depth obtained from the WM model (Weatherly and Martin, 1978),hPRT, is roughly the same as observed. The mixed layer depth calculated from the PWP model (Price, Weller and Pinkel, 1986) is close to the depth obtained from thermistor chain temperature data. The results show that both the WM model and PWP model can provide a good estimate of stratification in the study area during the cruise. The value of log( h/u3) is about 9.5 in the study area, which shows that the study area is strongly stratified in summer. Observations on the northern Portugal shelf reveal high variability in stability, giving rise to semi-diurnal, semi-monthly and diurnal oscillations, and long term variations. The fortnightly oscillatio     

山东省海(咸)水入侵演化趋势与防治对策探讨

山东省海(咸)水入侵主要有面状、带状、脉状或树枝状和越流等4种入侵方式。气候、地形地貌、地质与水文地质、风暴潮是发生海(咸)水入侵的自然因素;地下水超采、上游修建蓄水工程、发展海水养殖、扩建盐田、河道采砂和海岸带工程建设等人为因素是诱发海(咸)水入侵的主要原因。提出了工程措施和非工程措施两种防治海(咸)水入侵的对策。     

浙江省表层岩石及水系沉积物地球化学元素丰度研究

本文给出了浙江省及各地层分区的表层岩石41种元素 (含氧化物 )地球化学丰度 ;全省及浙西北、浙东南地层区的43种元素 (含氧化物 )的水系沉积物地球化学丰度 ;全省11个构造分区15种元素的平均含量、离差及异常下限值。并详细的介绍了样品的采集、分析测试方法和质量 ,以及丰度值的计算方法等 ,从而为浙江省勘查地球化学异常研究提供了背景资料     

西宁市光明小区浅震成果

隐蔽层是初至波方法不能探测到的速度层,它影响着初至波法的解释精度,本文讨论了隐蔽层存在的条件,并提出利用续至波探测隐蔽层的思路     

A Laboratory Column Study on Particles Release in Remediation of Seawater Intrusion Region

In coastal areas, excessive exploitation of groundwater causes seawater intrusion. In artificial recharge of aquifer remediation process, the replacement of saltwater and freshwater with each other causes colloid release, and permeability also decreases. In this paper, the aquifer samples containing minimal clay mineral(mainly illite) in Dagu River aquifer were used. Adopting horizontal column experiments, we studied the influences of seepage velocity and ionic strength on particle release, as well as the relationship between them. In the column experiments, the Critical Salt Concentration(CSC) of the Dagu River aquifer was determined as 0.05 mol L~(-1) approximately. This result was basically consistent with the DLVO theoretical calculation. For the constant seepage velocity, the salinity descending rate and partical release were slower, and the peak of particle concentration was lower. However, the total amount of released particles was almost constant at different salinity descending rate. For constant salinity descending rates, the peak of particle concentration decreased as seepage velocity increased, but the total amount of released particles rose up. The experiments also indicated the existence of a critical seepage velocity, which dropped with the decrease of salt concentration. When the concentration of Na Cl solution decreased from 0.17 mol L~(-1) to 0.06 mol L~(-1), the critical seepage velocity decreased from 3 cm min~(-1)to 2.5 cm min~(-1), which is consistent to the results predicted by DLVO theory.     

A new proposal for density salinity scale (DSS98)

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Salt-tolerant Microbiota Enhancing Contaminants Removal from Mariculture Wastewater Containing Sulfamethoxazole in an A/O-MBBR

The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment. During the wastewater treatment, the influence of antibiotics on the performance of bioreactor should be well revealed due to their toxicity to the functional microbial community. In this study, the effect of feeding 10-30 mg L~(-1) sulfamethoxazole(SMX) in influent on the performance of an anoxic/oxic-moving bed biofilm reactor(A/O-MBBR) treating mariculture wastewater and the responding change of biofilm microbial communities was investigated. The COD average removal rate remained at 94.61%-97.34% with the dosage of SMX. Compared with that, the nitrifying removals of NH_4~+-N and NO_2~--N were violently inhibited by 30 mg L~(-1) SMX and denitrifying removal of the NO_3~--N decreased obviously with 20 mg L~(-1) or more SMX. The microbial community in the successful startup bioreactor was relatively abundant, while the diversity of microbial community decreased with the increase of feeding SMX. The salt-tolerant and SMX-resistant genera Arcobacter, Thiothrix, Desulfuromusa and Nitrosomonas were gradually enriched and finally played a vital role in converting COD and recycling nitrogen and sulfur. Hence, the present A/O-MBBR reactor with the salt-tolerant functional microbiota achieved efficient removal of pollutants in the presence of low concentration(e.g., 10 mg L~(-1)) SMX.     

Effects of Sediment-induced Stratification on Floc Breakup in an Idealized Tidal Estuary： A Numerical Modelling Study

Floc breakup dynamics are studied by a sediment transport numerical model in an idealized tidal estuary that has a constant water depth and rapid flocculation of cohesive sediments. The focus is placed on the effects of boundary layer stratification induced by a bottom nepheloid layer on floc breakup and size distribution in the water column. In a neutrally stratified estuary, the floc size distribution follows a parabolic function with maximum values at the surface and bottom. The sediment-induced stratification in the bottom boundary layer increases the median floc sizes. Furthermore, sediment-voided convection caused by the settling lutocline generates significant turbulent kinetic energy dissipation and reduces floc size at the depth where the convective mixing happens. Below that depth, a weak local maxima in the floc size is predicted due to presence of the lutocline. The effect of sediment-stratified bottom boundary layer on the floc breakup can be consistently approximated by a linear regression between the maximal floc size and flux Richardson number.     

Effects of sediment-induced stratification on floe breakup in an idealized tidal estuary: A numerical modelling study

Floe breakup dynamics are studied by a sediment transport numerical model in an idealized tidal estuary that has a constant water depth and rapid flocculation of cohesive sediments. The focus is placed on the effects of boundary layer stratification induced by a bottom nepheloid layer on floe breakup and size distribution in the water column. In a neutrally stratified estuary, the floe size distribution follows a parabolic function with maximum values at the surface and bottom. The sediment-induced stratification in the bottom boundary layer increases the median floe sizes. Furthermore, sediment-voided convection caused by the settling lutocline generates significant turbulent kinetic energy dissipation and reduces floe size at the depth where the convective mixing happens. Below that depth, a weak local maxima in the floe size is predicted due to presence of the lutocline. The effect of sediment-stratified bottom boundary layer on the floe breakup can be consistently approximated by a linear regression between the maximal floe size and flux Richardson number.     

DISTRIBUTION AND COMPOSITION OF PAHs IN SURFACE WATERS, POREWATER AND SEDIMENTS FROM XIAMEN WESTERN BAY

Xiamen Western Bay‘s water and sedimem quality were studied by detemaining thelevels of sixteen polycyclic amrrmtic hydrocarbons PAHs in water, porewater and sediment samples from nine locations in the bay. Total PAH concentrations varied from 106 to 945 ng/1 in water, below detectionto 3548 ng/1 in porewater, and 247 to 480 ng/g dry weight in surface sediments. PAHs levels in porewaterwere higher than those in surface water, due to the preference of these hydrophobic compounds for sedimentary phase instead of water. Such a concentration gradient implies a potential flux of pollutants fromsediments to overlying water. The PAils levels in sediments were one to several orders of magnitude lowerthan those in 1993, suggesting their decreased input in recent years and possible degradation with time.     

DISTRIBUTION AND COMPOSITION OF PAHs IN SURFACE WATERS, POREWATER AND SEDIMENTS FROM XIAMEN WESTERN BAY

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An assessment of variations in mercury deposition to Antarctica over the past 34,000 years

We performed a comparison analysis of the variations .in Mercury ( Hg) concentrations and the precipitation proxies ( e. g. , 18 O values and 10 Be concentrations) in the Dome C ice core. The results showed that there were significant correlations between Hg and δ 10O values, 10Be concentrations, indicating that the accumulation rate in Dome C is one of the key factors controlling the variations of Hg concentrations in the past 34 ,000 years, and implying that Hg concentrations in ice core can be used as another reliable proxy of precipitation rate in Antarctica. Based upon the high-resolution δ 18O values, we estimated the variations in mercury deposition flux to Antarctica over the past 34,000 years. The highest mercury deposition flux is about 3. 80 pg cm-2 yr-1 during the Last Glacial Maxium (LGM) as high as 3. 5 times of the mercury deposition flux ( about 1. 08 pg cm -2 yr -1) in Holocene due to the fluctuations in natural mercury emissions such as the oceanic biological emissions.     

基于细化分层法探讨面波频散曲线反演参数的简化

常规频散曲线反演过程中需要不停地改变分层数、层厚度和层速度等参数,实现过程相对繁琐,而采用细化分层法对反演参数进行简化则避免了上述缺点。具体思路为:根据目的层探测深度(如20m)将地下介质分为若干个(20个)厚度为1m的薄层和1个均匀半空间层(共21层),这样在反演中分层数和层厚度均为已知参量,反演过程只需修改速度参数即可,避免了改变分层数和层厚度等参数,显著简化了反演计算过程。正演计算和反演结果均表明:细化分层与实际分层计算出的频散曲线是等效的,细化分层反演结果的总体效果与真实模型非常接近,这说明细化分层方法用于频散曲线反演是切实可行且有效的;将地下介质划分为1m厚的薄层,反演后每层均可得到1个横波速度,能满足反演分辨率的要求;由于实际地下介质的速度是随深度渐变的,细化分层后比按频散曲线拐点分层(每分层的厚度可能是几米或几十米,同一分层内介质的横波速度相等)更接近实际情况。     

Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary

An improved 3-D ECOM-si model was used to study the impact of seasonal tide variation on saltwater intrusion into the Changjiang River estuary, especially at the bifurcation of the North Branch (NB) and the South Branch (SB). The study assumes that the river discharge and wind are constant. The model successfully reproduced the saltwater intrusion. During spring tide, there is water and salt spillover (WSO and SSO) from the NB into the SB, and tidally averaged (net) water and salt fluxes are 985 m3/s and 24.8 ton/s, respectively. During neap tide, the WSO disappears and its net water flux is 122 m3/s. Meanwhile, the SSO continues, with net salt flux of 1.01 ton/s, much smaller than during spring tide. Because the tidal range during spring tide is smaller in June than in March, overall saltwater intrusion is weaker in June than in March during that tidal period. However, the WSO and SSO still exist in June. Net water and salt fluxes in that month are 622 m3/s and 15.35 ton/s, respectively, decreasing by 363 m3/s and 9.45 ton/s over those in March. Because tidal range during neap tide is greater in June than in March, saltwater intrusion in June is stronger than in March during that tidal period. The WSO and SSO appear in June, with net water and salt fluxes of 280 m3/s and 8.55 ton/s, respectively, increasing by 402 m3/s and 7.54 ton/s over those in March. Saltwater intrusion in the estuary is controlled by the river discharge, semi-diurnal flood-ebb tide, semi-monthly spring or neap tide, and seasonal tide variation.