四种饵料微藻对海水养殖水体N、P的去除研究

为了探索采用微藻处理与综合利用技术净化工厂化海水养殖水体的可行性,研究测定了一些常用饵料微藻对水体N、P的去除能力。主要以绿色巴夫藻(Pavlova viridis)、青岛大扁藻(Platymonas sp.)、三角褐指藻(Phaeodactylum tricornutum)和塔胞藻(Pyramimonas sp.)为研究对象,首先选择起始藻细胞数量、盐度、光照和温度四种因素开展正交试验确定四种饵料微藻最优生长条件,然后在最优生长条件下研究四种饵料微藻对水体N、P的去除效果。结果表明在优化生长条件下,四种饵料微藻对工厂化海水养殖水体NH4+-N和PO43--P均具有较好去除效果,但对NO3--N去除率不高。四种饵料微藻中塔胞藻去除水体N、P能力最强,在藻细胞起始密度为1.5×105 cells/mL,盐度为20‰,光照强度为5 000 lx,温度为20℃时,经过6 d处理,对NH4+-N和PO43--P去除率均高于99%;对NO3--N的去除率为15.4%,显著的高于青岛大扁藻和绿色巴夫藻。

研究海水温盐结构的反射地震方法

在物理海洋学的研究中,利用CTD(Conductivity,Temperature and Depth sensors)测量方法研究海水温盐结构存在着获取数据时间长、数据横向精度低的缺点,而利用反射地震记录可以获得剖面上连续的水体温盐结构,弥补了传统方法的不足。反射地震方法研究海水温盐结构是个新的交叉学科方法,称为"地震海洋学"。由于海水水体的物性变化比地层物性变化小得多,造成海水水体的反射地震资料信噪比很低,各类干扰强烈,因而海水水体的反射地震资料处理也和常规地震资料处理方法有所不同。它处理的重点是振幅补偿,叠前去噪以及叠后处理。笔者通过对"十五"973项目在南海东北部采集的一条高分辨率多道反射地震测线的海水水体部分的地震数据进行处理,压制了强线性干扰波,获得了水体反射图像。地震叠加速度分析获取的3个CDP(Common Depth Point)的垂向速度从1540 m.s-1单调减小到1478 m.s-1,与CTD测量得到的速度变化趋势一致。

生物滤器处理海水养殖水过程中亚氮积累与影响因素

实验研究了竹环填料曝气生物滤器在处理高盐度、低氨氮负荷的海水养殖水体过程中NO2--N的积累现象,考察了进水有机负荷、NH4+-N负荷、温度、pH值和溶解氧等运行条件以及反硝化作用对NO2--N积累的影响.结果表明,在进水有机负荷为0.65～0.75kg/(m3·d)、NH4+-N负荷为0.058～0.077kg/(m3·d)、温度为20.9～22.2℃、pH值为7.50～8.14和溶解氧为7.43～9.73mg/L条件下,生物滤器内较低的溶解氧(0.91～1.36mg/L)是NO2--N积累的主要原因.同时,研究了反硝化过程中低溶解氧、不同碳氮比(C/N)及碳源类型等因素对NO2--N积累的影响,查明了生物滤器内含氮化合物的浓度变化与反硝化细菌的数量和功能,验证了反硝化过程对NO2--N积累的影响,明确了反硝化作用对NO2--N积累的促进作用.

星洲红鱼海水网箱养殖试验

星洲红鱼是罗非鱼属内种间杂交选育出的遗传性状较为稳定的罗非鱼新品种。星洲红鱼在淡水中养殖生长表现优于其他罗非鱼品种。将其在海水驯化适应后投入到海水小体积网箱中进行高密度养殖试验 ,生长性状良好 ,成鱼外观美 ,肉质好 ,口感佳 ,成活率高 ,产量高 ,市场前景广 。

利用绿色巴夫藻去除海水养殖水体中N、P的条件优化

为了研究常用饵料微藻绿色巴夫藻对高密度海水养殖水体中N、P的去除能力,探索去除养殖水体中N、P的最优条件,选择起始藻细胞数量、养殖水体稀释率、温度、光照和盐度五种因素开展正交试验。结果表明养殖水体稀释率为50%时,绿色巴夫藻对NH4-N和PO4-P的平均去除率最高,分别为98.7%和85.5%。各种因素影响藻体去除水体中N、P的主次顺序为养殖水体稀释率>起始藻细胞数量>温度>盐度>光照强度,最优方案是起始藻细胞数量为5×105/mL,养殖水体稀释率为50%,盐度为30,光照强度为5 000 lx,温度为25。

海产养殖水体中复杂组分致光催化剂杀菌失活的机理研究

光催化技术在养殖水体净化方面具有很好的应用前景。然而,海水水产养殖水体组分复杂,造成光催化剂失活的机理鲜有研究。以典型近海养殖水体为研究对象,重点探讨以腐殖酸为典型天然有机物(NOM)组分,以细菌和真菌作为主要微生物,对光催化剂TiO_(2)纳米管杀菌失活的影响机制进行研究。发现在汕头海水养殖水体中,0-8 h细菌(k=0.23 h^(-1))和真菌(k=0.32 h^(-1))具有较高的杀菌效率,在8-24 h阶段细菌杀菌效率(k=0.03 h^(-1))开始下降,在湛江海水养殖水体中也观察到同样的趋势;在珠海海水养殖水体中,前0-8h对细菌(k=0.14h^(-1))有较高的杀灭效率,在0-6h内对真菌也具备较高的杀灭效率(k=0.24 h^(-1)),细菌和真菌分别在8 h和6 h时杀菌效率变化明显。并且3个地点的水样分别在杀菌48、48、8h后菌体数量呈现增长的现象,这可能与菌体的VBNC状态有关。同时,通过微生物多样性测定发现在海水养殖水体中假单胞菌为优势菌种;衣原体,支原体和军团菌3种细菌菌属在杀灭过程中细菌的占比减少程度最大。通过使用稳态瞬态荧光光谱仪结合PARAFAC和荧光区域积分法(FRI)得到3个不同地区水体样品的腐殖酸的降解程度均在40%以上;最后通过ATR-FTIR、SEM-EDS等实验表征,验证了在杀菌过程中,腐殖酸中间产物以及菌体破裂泄漏的生物分子附着在TiO_(2)纳米管表面并堵塞部分微孔,堵塞了催化剂表面的活性位点,致使光催化剂加速失活。对光催化技术应用于环境复杂水体处理中的失活现象和机理进行研究,可填补此领域的空白。

Water Masses in the South China Sea and Water Exchange between the Pacific and the South China Sea

Water masses in the South China Sea (SCS) were identified and analyzed with the data collected in the summer and winter of 1998. The distributions of temperature and salinity near the Bashi Channel (the Luzon Strait) were analyzed by using the data obtained in July and December of 1997. Based on the results from the data collected in the winter of 1998, waters in the open sea areas of the SCS were divided into six water masses: the Surface Water Mass of the SCS (S), the Subsurface Water Mass of the SCS (U), the Subsurface-Intermediate Water Mass of the SCS (UI),the Intermediate Water Mass of the SCS (I), the Deep Water Mass of the SCS (D) and the Bottom Water Mass of the SCS(B). For the summer of 1998, the Kuroshio Surface Water Mass (KS) and the Kuroshio Subsurface Water Mass (KU) were also identified in the SCS. But no Kuroshio water was found to pass the 119.5°E meridian and enter the SCS in the time of winter observations. The Sulu Sea Water (SSW) intruded into the SCS through the Mindoro Channel between 50-75 m in the summer of 1998. However, the data obtained in the summer and winter of 1997 indicated that water from the Pacific had entered the SCS through the nor-thern part of the Luzon Strait in these seasons, but water from the SCS had entered the Pacific through the southern part of the Strait. These phenomena might correlate with the 1998 El-Nio event.

Shallow Water Body Data Processing Based on the Seismic Oceanography

Physical properties of sea water,such as salinity,temperature,density and acoustic velocity,could be demarcated through degradation of energy caused by water absorption,attenuation and other factors.To overcome the challenging difficulties in the quick monitoring of these physical properties,we have explored the high resolution marine seismic survey to instantly characterize them.Based on the unique wavefield propagating in the sea water,we have developed a new approach to suppress the noise caused by the shallow sea water disturbance and obtain useful information for estimating the sea water structure.This approach improves seismic data with high signal-to-noise ratio and resolution.The seismic reflection imaging can map the sea water structure acoustically.Combined with the knowledge of local water body structure profile over years,the instant model for predicting the sea water properties could be built using the seismic data acquired from the specially designed high precision marine seismic acquisition.This model can also be updated with instant observation and the complete data processing system.The present study has the potential value to many applications,such as 3D sea water monitoring,engineering evaluation,geological disaster assessment and environmental assessment.

ON STRONG SIGNALS OF MONTHLY PRECIPITATION ANOMALIES IN EARLY RAINING SEASON OF GUANGDONG AND CONCEPTUAL MODELS OF PREDICTION

Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss).