Salinity influence on soil microbial respiration rate of wetland in the Yangtze River estuary through changing microbial community

Estuarine wetland, where freshwater mixes with salt water, comprises different regions（rivers and marine ecosystems） with significantly varying tidal salinities. Two sampling areas, ZXS and JS, were selected to investigate the effect of tidal salinity on soil respiration（SR）. ZXS and JS were located in Zhongxia Shoal and Jiangyanan Shoal of Jiuduansha Wetland respectively, with similar elevation and plant species, but significantly different in salinity. The results showed that with almost identical plant biomass, the SR and soil microbial respiration（SMR） of the tidal wetland with lower salinity（JS） were significantly higher than those of the tidal wetland with higher salinity（ZXS）（p 〈 0.05）. However, unlike SMR and SR, the difference in the soil microbial biomass（SMB） was not significant（p 〉 0.05）with the SMB of ZXS a little higher than that of JS. The higher SMR and SR of JS may be closely connected to the soil microbial community structures and amount of dominant bacteria. Abundant β- and γ-Proteobacteria and Actinobacteria in JS soil, which have strong heterotrophic metabolic capabilities, could be the main reason for higher SMR and SR,whereas a high number of ε-Proteobacteria in ZXS, some of which have carbon fixation ability, could be responsible for relatively lower carbon output. Path analysis indicated that soil salinity had the maximum negative total influencing coefficient with SMR among the various soil physical and chemical factors, suggesting that higher soil salinity, restricting highly heterotrophic bacteria, is the principle reason for lower SMR and SR in the ZXS.     

东海赤潮高发区半分析算法色素浓度反演

为研究赤潮机理和预测预报以减少其危害,根据2002-04东海赤潮调查航次实测资料,得出经验系数,建立方程,发展了东海赤潮高发海区的叶绿素a浓度反演半分析算法.由现场实测数据对算法进行检验,叶绿素a吸收系数a_ph(675)及浓度的反演结果误差基本在30%以内,其中浓度反演结果比较,均方根偏差为0.24,最大相对偏差为40.93%,平均相对偏差为18.83%,相关系数R²为0.83.从检验的结果来看,算法反演的精度较好,对于研究海区相对适用.     

光照与东海近海中肋骨条藻(Skeletonema costatum)赤潮发生季节的关系

利用船基现场培养实验和模型计算的方法,研究了光照与东海近海春夏季均能发生中肋骨条藻赤潮的关系.结果表明,中肋骨条藻生长的最适光照强度(I_opt)随水温(t)的增加呈“慢升快降”的不对称“倒V”形变化特征,在25℃左右I_opt最大,为121.6 Ｗ·m^-R, I_opt-t 曲线符合Blanchard方程; 由东海海表水温计算的中肋骨条藻I_opt的季节变化特征与东海海面光照强度、海水透明度的季节变化基本同步(R^R=0.907±0.115, p<0.001),且滞后于海面光照强度2个月左右,这使春夏季海水中光照最适宜生长的水层均为全年最厚(6m左右).可见,中肋骨条藻对光照的适应性很强,海区海水光照的适宜性是春夏季均能形成大规模中肋骨条藻赤潮的重要原因之一.     

浙江近岸有害赤潮发生区麻痹性贝毒素研究

用小白鼠生物检测法和高效液相色谱法对采自浙江舟山海域和浙江中南部海域的麻痹性贝毒素进行了调查分析。结果表明:浙江舟山海域六横岛的西格织纹螺含有贝毒,其毒素含量为3.7 Mu/g,舟山海域有毒贝类检出率为3.1%。浙江中、南部海域南麂列岛的棒锥螺含有贝毒,其毒素含量<1.7 Mu/g,浙江中、南部海域有毒贝类检出率为9.1%。     

东海海面太阳辐射近60a的变化与赤潮的关系

为了在年代尺度上分析太阳辐射与海洋赤潮之间的关系,利用NCEP再分析资料分析了东海海面太阳总辐射通量近60 a的变化特征.结果表明,近60 a来,东海北部海域海面太阳总辐射通量平均在198 W/m2左右,海面太阳总辐射通量以20 a左右的周期在波动中逐渐升高,自20世纪50年代末的谷期至今,年均上升率在0.5 W/m2·a左右,升幅在11%左右.而且进入21世纪后升幅尤为显著,与东海赤潮规模在此间的增加趋势一致.由于为赤潮藻提供生长所需的光照,太阳辐射的增加可能是导致东海赤潮发生次数和面积增加的原因之一,这对海洋赤潮预报和防治工作具有科学参考价值.     

Stratification and Tidal Current Effects on Larval Transport in the Eastern English Channel: Observations and 3D Modeling

We study how the combination of tides and freshwater buoyancy affects the marine organisms accumulation and horizontal transport in the ROFI system of the eastern English Channel. The Princeton Ocean Model coupled with a particle-tracking module is used to study the migration of fish eggs and larvae under different forcing conditions. Results of modeling are validated against observed concentrations of Flounder (Pleuronectes flesus) larvae. Numerical Lagrangian tracking experiments are performed with passive and active particles, representing sea-water organisms. Passive particles are neutrally buoyant whereas active particles are able to exercise light dependent vertical migrations equating to the swimming behavior of larvae. The experiments reveal that the strongest accumulation of particles occurs along the French coast on the margin of the ROFI. This happens because the interaction between the turbulence, the freshwater buoyancy input, and tidal dynamics, produces particle trapping and vertical spreading within the frontal convergence zone. Tides and freshwater input induce net alongshore horizontal transport toward the North. Tidal currents modulate the magnitude of horizontal transport whereas the fresh water input controls more the location of accumulation zones. Tracking experiments with active particles indicate that the vertical migration leads to a significant departure from the passive particle transport pattern. Differences lie in the shape of the particle transport pattern and the rate of the northward migration. In particular, vertically migrating particles travel slower. To find possible Flounder migration pathways, particles are released within the assumed spawning area of Flounder. The model predicts larvae drift routes and demonstrates that throughout the entire particle-tracking period the horizontal structure of the particle distribution is consistent with the larvae concentrations observed during the field experiments.     

浙江近岸海域有害赤潮发生区麻痹性贝毒素研究

用小白鼠生物检测法和高效液相色谱法对采自浙江舟山海域和浙江中南部海域的麻痹性贝毒素进行了调查分析。结果表明,浙江舟山海域六横岛的西格织纹螺含有贝毒,其毒素为3,7Mu／g,舟山海域有毒贝类检出率为3．1％;浙江中南部海域南麂列岛的棒锥螺含有贝毒,其毒素〈1.7Mu／g,浙江中、南部海域有毒贝类检出率为9．1％。     

大气气溶胶中铁的酸化与东海赤潮

气溶胶中微量元素的大气输送过程对海洋初级生产力有重要意义,其中铁对海洋生物至关重要,也可能成为影响赤潮的关键因子.本文在综述了大气中酸性物质对气溶胶铁的酸化,在铁从不溶态转变为可溶态的关键过程基础上,提出了东海赤潮的发生可能与大气酸化气溶胶铁密切相关.酸化后的可溶性铁在东海赤潮区下沉可能与沿岸洋流从冬、夏季环流转换提供水动力条件共同作用.该设想将为探索赤潮灾害发生机理提供一些参考,对最终预警预报赤潮发生,降低赤潮灾害的损失,保护海洋生态环境具有重要意义.     

深圳市污染物排放总量与近岸水体营养盐变化的统计分析(IV)

从统计学角度分析深圳市污染物净排放总量与其近岸东、西部水体富营养化之间关系。研究结果表明:深圳市东部海域水体活性磷酸盐、EI值以及西部海域水体中的N:P分别与近岸排污呈现较好的相关性,他们似可作为深圳排污与近岸水体富营养化关系指标。深圳东西部水体由于地理条件、海湾的封闭性的差异,造成东部水体更易受到深圳近岸排污的影响,而西部水体较为开放,受珠江水系、深圳和香港排污等多重因素的影响,因此在研究深圳近岸污染物排放总量与赤潮发生关系时,应选择东部水体作为研究对象。     

CVM中的抗议性响应:动机与影响——以胶州湾浒苔治理支付意愿为例

抗议性响应是意愿调查法应用中受访者表现出的典型策略性行为,可能导致对资源环境物品或服务的估值出现偏差。识别抗议性响应影响因素并降低其对支付意愿的影响,有助于提高CVM估值效度。以胶州湾海域居民浒苔治理支付意愿为例,以抗议性信念作为受访者抗议性响应的度量指标,筛选抗议性信念的驱动因素,量化各驱动因素对支付意愿的影响方向及程度。研究结果表明:（1）愿意支付的受访者仍然具有抗议性信念,且在个别测量题项中,其抗议性信念甚至高于拒绝支付群体。（2）环境关注、搭便车顾虑、暖光效应等变量均对受访者抗议性信念存在影响。（3）抗议性信念水平对受访者参与决策与支付意愿金额均存在显著负向影响,抗议性信念变量对参与和支付决策的影响方向与程度存在差异,进一步证明参与和支付决策是不同的机制。研究结论将对优化CVM问卷设计、规范操作流程、减少评估偏差具有指导意义。