水体中TN/TP与藻类产生周期及产生量的关系

通过室内模拟的方法研究了用自来水作为试验水,当TN/TP在25∶1～4∶1的范围变化时,藻类的产生周期及产生量的变化情况.试验设置了25∶1,20∶1,15∶1,12∶1,10∶1,4∶1 6个比值.为了探讨温度对藻类产生的影响,分别在夏季和冬季做了对比试验.结果表明:当TN/TP在25∶1～12∶1的范围时,藻类的产生周期随TN/TP的减少而缩短,产生量随着TN/TP的减少而增加.在TN/TP为12∶1时藻类的产生周期最短,产生量最多.而TN/TP从12∶1～10∶1时,藻类的产生周期却随TN/TP的减少而增加,产生量随TN/TP的减少而减少.在TN/TP为4∶1时,没有产生藻类.季节对藻类的产生影响比较大.在夏季,藻类的产生周期较短,生产量较多;在冬季,藻类的产生周期较长,生产量相对较少.     

Response of the northwestern Pacific upper water δ~(13)C to the last deglacial ventilation of the deep Southern Ocean

The deglacial δ~13C minimum events that originated from the ventilation of the deep Southern Ocean around Antarctica, have been recorded in a range of marine sediments from the southern to tropical oceans in late Pleistocene. However, the broad δ~13C minimum event was also reported as far as to the northern middle latitudes, in northwestern Pacific marginal sea areas, during the last deglaciation. In the northwestern Pacific, forcing from the northern high latitudes is strongly expressed, while the records of in- fluence from the southern high latitudes are few. The Kuroshio Source Region (KSR) forms a boundary between the northwestern Pacific and the southern, tropical Pacific. So, high-resolution planktonic foraminiferal records in core MD06-3054 from the KSR are well positioned to identify signals from the southern hemisphere in the northwestern Pacific. Planktonic foraminiferal tests from the upper 1030 cm of the core were subject to AMS14C, carbon and oxygen isotopic measurements. A negative excursion was found to occur from about 20.0-6.0 ka BP in δ~13C records of both surface (Globigerinoides ruber) and subsurface (Pulleni- atina obliquiloculata) dwellers, but the overall trends of the two curves have reversed since 26.5 ka BP. Moreover, the δ~13C rec- ord of G. ruber (the surface dweller) shows a robust link to the record of atmospheric CO2, and its changes precede the records of P. obliquiloculata (the subsurface dweller). According to the hydrologic conditions, the broad δ~13C minimum event recorded in the KSR is also a response to the increasing ventilation of the deep Southern Ocean around Antarctica during the last deglaciation. The inconsistency between the records of the surface and subsurface dwellers was possibly caused by the ways that the low δ~13C signal was transmitted. Subsurface water primarily received the low δ~13C signal from the Antarctic Intermediate Water (AAIW), whereas the surface water was probably mainly impacted by atmospheric CO2 in the KSR. The records from the KSR confirm the deduction that the broad δ~13C minimum event in the Okinawa Trough was due to the impact of tropical Pacific surface water dur- ing the last deglaciation, and suggest that signals from the southern high latitudes also can be delivered to the northern middle latitudes.     

海洋酸化正负效应:藻类的生理学响应

大气CO2浓度升高,引起海洋酸化,使得海水pCO2、H+和HCO3-浓度增加,CO32-浓度下降,并导致CaCO3的饱和度下降.海水pCO2升高,促进某些藻类的光合作用与生长,特别是在光能不足的情况下,这种促进效应尤其明显.然而,海水酸性的增加导致钙化藻类钙化量下降,蒙受阳光UV辐射的损害增加,威胁其生存.即使非钙化藻类,如某些硅藻类和赤潮藻类,pCO2升高引起的海水酸性增加可降低其耐受高光胁迫的能力,加大光抑制,且增加其呼吸作用.因此,海洋酸化究竟会导致海洋光合固碳量增加还是减少,取决于酸化与CO2浓度升高"双刃剑"效应的平衡,也就是取决于海洋酸化正、负效应的平衡.在不可逆转的海洋酸化进程中,藻类必然进行生理调节并适应酸化带来的海水化学胁迫,由此,遗传或进化方面的变化也会发生.海洋从大气中吸收CO2的量,依赖于藻类光合作用驱动的CO2生物泵,自然也依赖于海洋酸化的正、负效应.     

关于海藻吸附水溶液中重金属离子的研究进展

海藻作为生物吸附剂处理低浓度重金属废水,具有成本低、吸附量大、选择性好、操作条件范围宽、金属可回收再利用等优点,并且吸附过程中没有污泥等二次污染物的产生。综述和分析了海藻对重金属离子的吸附机理、影响因素、吸附平衡和动力学模型,阐明了今后的研究方向。     

不同水体沉水植物叶面微生物群落特征

以沉水植物黑藻(Hydrilla verticillata)、苦草(Vallisneria natans)、伊乐藻(Elodea nuttallii)和菹草(Potamogeton crispus L)为研究对象,利用扫描电镜、荧光显微镜和16S rRNA基因高通量测序技术,探究不同生境中沉水植物叶面附着微生物群落结构及影响因素。结果表明：沉水植物叶面附着藻类组成与环境水体的藻类组成具有明显差异;不同沉水植物叶面附着微生物密度不同,且河流样品中高于湖泊样品;α-变形菌、β-变形菌和γ-变形菌纲是沉水植物叶面附着生物膜上的主要细菌纲,这些纲具有降解污染物质、净化水体的功能;水体营养盐浓度对沉水植物叶面附着微生物群落结构有很大影响。     

4种淡水藻对硝基苯的抗性机制

选择了4种淡水藻——纤细裸藻、莱因衣藻、舟形藻和聚球藻,通过分析硝基苯对其生长和叶绿素含量的影响,以及藻细胞对硝基苯的降解、积累和抗氧化酶系统的响应,以期了解藻类对硝基苯的抗性机制．结果表明：4种藻的生长和叶绿素a含量对硝基苯的抗性,按抗性大小排列：纤细裸藻〉莱因衣藻〉舟形藻〉聚球藻,4种藻对硝基苯无显著的降解和积累能力,藻细胞对硝基苯的抗性主要依赖抗氧化酶系的防御作用,其中藻细胞的SOD起主要作用,POD起次要作用．     

基于多元共生遗传神经网络的藻类预测仿真

提出一种多元共生遗传神经网络(PGANN),从遗传算法和神经网络——进化和学习两方面及其相互关系着手完善进化过程,以提高优化效果和泛化能力。该算法包括一个共生平衡交叉算子,一种多元选择策略和一种神经网络的分级优化策略,其中共生平衡算子能够兼顾进化过程中的方向性、多样性和自适应性;多元选择策略能够适应进化过程不同时段对选择压力不同的需求;而分级优化使运算规模和运算速度之间的矛盾得到缓解。将该改进的遗传神经网络PGANN应用于水库和湖泊有毒的优势蓝绿藻爆发预测,取得了满意的效果。     

乌金塘水库春季藻类研究初报——锦州地区藻类研究之一

乌金塘水库是辽宁省大型水库之一,关于该水库的藻类资源的研究报导在国内尚属首次。文中着重对该水库发现的35属98种及其变种(其中5属40种是本省新记录)的种群组成特征,生态因子进行了分析。     

西安南五台色球藻科蓝藻类的研究

本文报道了西安南五台山的色球藻科蓝藻30种(其中包括变种),并对这些种在不同生态环境和不同林带的生态分布作了初步研讨.