Role of Microbes in the Production and Source of Marine Colored Dissolved Organic Matter

海洋碳循环是目前全球气候变化背景下的一个迫切需要研究的科学命题。而寻找合适的指标跟踪海洋有机碳的动态过程是进行海洋碳循环研究的一个有效的研究手段。海洋有色溶解有机质是具有光活性的一类溶解有机质，其产生和消耗过程能够为研究海洋碳循环动态研究提供翔实可靠的依据。微型生物在海洋有机质的循环过程是海洋碳循环研究的重要内容。本研究着眼于海洋微型生物，以具有光活性效应的有色溶解有机质（CDOM）作为研究目标，通过航次甲板现场培养实验和实验室室内实验相结合，探究微型生物在CDOM的源和汇中的作用，从而为揭示微型生物在海洋碳循环中的作用提供可靠的数据。 本研究比较了无菌浮游植物和异养细菌产生类蛋白CDOM和...Ocean carbon cycling in the changing climate is an urgent topic in marine science research area. Marine microbes play important role in the dynamic and cycling of oceanic organic carbon pool, which refers not only the particulate carbon but also the more abundant dissolved organic carbon pool. Colored dissolved organic matter (CDOM) is a complex of optical active substances and represents an impor...学位：博士后院系专业：海洋与环境学院环境科学研究中心_环境科学学号：BH1700006

Decline of Microcystis aeruginosa FACHB-905 under four stress conditions

研究了四种胁迫条件下微囊藻衰亡过程以及衰亡过程中生长生理与抗氧化酶系统的变化以及胁迫30d后转入正常培养后的微囊藻的生长变化过程.将对数生长期的微囊藻分别转入氮饥饿、磷饥饿、黑暗及10℃低温等胁迫条件下培养,测定光密度OD680、叶绿素a、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性等生理指标.结果表明,在黑暗和低温条件下,微囊藻生长受到明显抑制,但黑暗条件下25d后微囊藻衰亡,低温条件下仅需7d;与物理因子引起的胁迫相比,在营养胁迫条件下,微囊藻在胁迫前期均表现出生长趋势.N饥饿条件下叶绿素a含量从开始胁迫后即下降,P饥饿20d后叶绿素a含量以0.1mg/(L·d)急剧下降,在四种胁迫条件中下降速率最高,表明微囊藻对P的耐受能力最差.根据实验结果,在长期没有外来P源供给而内部又无可得P源的水体中、或者水温急剧下降到10℃以下时,微囊藻水华可能会快速衰亡,相应的应急措施应准备到位,以尽量减轻水体微囊藻水华衰亡带来的损失.SOD与CAT活性的上升与叶绿素a含量的下降存在显著相关性,可以尝试将两者结合预测微囊藻水华的衰亡.本研究在实验室条件下初步探讨了四种环境因子对微囊藻消亡的贡献,比较了SOD与CAT活性与叶绿素a含量下降的相关性,为微囊藻水华衰亡预测体系的建立提供了理论依据.The present study aimed to evaluate the contribution of stress factors to the decline of Microcystis bloom, also tried to develop some indicator of decline. Four stress conditions including nitrogen starvation, phophorus starvation, dark and low temperature (10℃) were designed. Decrease of biomass and the concomitant change of antioxidant system, including superoxide dismutase (SOD) and catalase (CAT) activities were detected. The result indicated that growth was significantly inhibited under dark and low temperature. Microcystis population declined after 25 days under dark, while declined after only 7 days under low temperature. Compared with the physical stress, nutrition such as nitrogen and phosphorus did not limit the growth effectively in the early stage. Chlorophyll-a decreased as soon as being incubated into nitrogen free BG-11 medium. After being kept in phosphorus free medium for 20 days, chlorophyll-a reached peak, about the twice of the initial concentration, and then decreased at a rate of 0.1mg/(L·d), which was the highest decaying rate among the four factors. It indicated its significance of available phosphorus for Microcystis survival and decline. According to the results, when phosphorus was limited, or water temperature was decreased to 10℃, cautions should be taken into account for the decrease of dissolved oxygen and possible increase of toxins or odors substances from the declining bloom. In healthy Microcystis, SOD activity was about 0.06U/mg protein, while CAT activity was too low to be measured. In addition, SOD activity increased earlier than CAT activity when Microcystis was exposed to stress conditions. CAT activity increased only when the content of chlorophyll-a began to decline. Both of the increase of SOD and CAT activities correlated negatively with the decrease of the content of chlorophyll-a though there were some exceptions. Combination of the two parameters would be potential indicator of bloom decline.国家高技术研究发展计划863项目(2005AA60101005);; 中国科学院知识创新工程重要方向项目(KZCX2-YW-426)联合资

微囊藻衰亡过程研究——四种模拟胁迫条件下微囊藻的衰亡生理

研究了四种胁迫条件下微囊藻衰亡过程以及衰亡过程中生长生理与抗氧化酶系统的变化以及胁迫30d后转入正常培养后的微囊藻的生长变化过程．将对数生长期的微囊藻分别转入氮饥饿、磷饥饿、黑暗及10℃低温等胁迫条件下培养，测定光密度OD680、叶绿素a、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性等生理指标．结果表明，在黑暗和低温条件下，微囊藻生长受到明显抑制，但黑暗条件下25d后微囊藻衰亡，低温条件下仅需7d；与物理因子引起的胁迫相比，在营养胁迫条件下，微囊藻在胁迫前期均表现出生长趋势．N饥饿条件下叶绿素a含量从开始胁迫后即下降，P饥饿20d后叶绿素a含量以0．1mg／（L-d）急剧下降，在四种胁迫条件中下降速率最高，表明微囊藻对P的耐受能力最差．根据实验结果，在长期没有外来P源供给而内部又无可得P源的水体中、或者水温急剧下降到10℃以下时，微囊藻水华可能会快速衰亡，相应的应急措施应准备到位，以尽量减轻水体微囊藻水华衰亡带来的损失．SOD与CAT活性的上升与叶绿素a含量的下降存在显著相关性，可以尝试将两者结合预测微囊藻水华的衰亡．本研究在实验室条件下初步探讨了四种环境因子对微囊藻消亡的贡献，比较了SOD与CAT活性与叶绿素a含量下降的相关性，为微囊藻水华衰亡预测体系的建立提供了理论依据

金藻吞噬微囊藻产生的无毒变异株与产毒原始株的比较

分别从喂食三株原始产毒铜绿微囊藻Microcystis aeruginosa(AC、DS和PCC 7820)的金藻Poterioochromonassp.培养物中获得三株藻,以Nest PCR方法(引物对CC/CG和CH/CI)确定此三株藻均为微囊藻属藻株。HPLC测试结果显示这三株藻均不产生微囊藻毒素。显示Poterioochromonassp.具有将产毒微囊藻转化为无毒微囊藻的能力。比较产毒原始株与无毒变异株的生理特性发现,变异株的类胡萝卜素/叶绿素比值高于原始株;而光反应曲线结果表明,变异株的PS

营养条件对铜锈微囊藻胞外多糖形成的影响

铜锈微囊藻可合成胞内多糖;粘鞘多糖和胞外可溶性多糖( Eps)。自然状态下;微囊藻都是粘鞘多糖包裹下的群体形态;但一旦转入实验室培养;微囊藻最终都失去群体形态而成为单细胞状态。我们以葡萄糖作为标准;以蒽酮法测定了同等培养条件下群体和单细胞铜锈微囊藻的胞外可溶性多糖合成;结果表明;群体微囊藻合成的eps大大高于单细胞微囊藻;这说明群体微囊藻转变成单细胞后;其粘鞘多糖并没有成为eps;而是单细胞微囊藻

营养条件对水华蓝藻铜绿微囊藻的胞外多糖产生的影响

当自然条件下的群体微囊藻转入实验室培养后,它们的胶被多糖往往急剧下降,形态由群体解聚为单细胞。M icrocystis aeruginosaDCA(群体)和M.aeruginosaDCS(单细胞)是同源而形态不同的两株微囊藻,对它们的研究在一定程度上可展示微囊藻群体解聚机制。研究显示两株微囊藻在正常培养基中的生长和EPS产量差异很大,单细胞微囊藻生长快但EPS产量少,群体微囊藻正相反。以单细胞微囊藻为材料研究N,P,S,Fe和EDTA等营养元素对EPS产生的影响,实验浓度为正常培养基中营养元素的5倍和1

营养条件对水华蓝藻铜绿微囊藻的胞外多糖产生的影响

当自然条件下的群体微囊藻转人实验室培养后，它们的胶被多糖往往急剧下降，形态由群体解聚为单细胞。Microcystis aeruginosa DCA（群体）和M.aeruginosa nDCS（单细胞）是同源而形态不同的两株微囊藻，对它们的研究在一定程度上可展示微囊藻群体解聚机制。研究显示两株微囊藻在正常培养基中的生长和EPS产量差异很大，单细胞微囊藻生长快但EPS产量少，群体微囊藻正相反。以单细胞微囊藻为材料研究N，P，S，Fe和EDTA等营养元素对EPS产生的影响，实验浓度为正常培养基中营养元素的5倍和1／5。结果显示，在N缺乏条件下，单细胞微囊藻生长很慢，大约在第6天停止生长，其他营养条件的改变对单细胞微囊藻的生长没有明显的影响，在N缺乏条件下单细胞微囊藻的EPS含量在第3天达到最高，然后急剧下降；5倍的N条件显著刺激EPS的产生，P丰富的条件也轻微刺激EPS的产生。其他营养条件的改变对生长和EPS产生的影响都不明显。我们的结果与一般规律显著不同，即在某些产生EPS的微藻，N缺乏刺激多糖合成

Study on the Silicides in Cuticle of Wheat Straw Stem by Means of XPS(Ⅱ)

用X射线光电子能谱法(XPS)研究了麦秆节间不同部位皮层的硅化物组成及含量,探索皮层硅化物的碱稳定性。结果表明,在实验条件下,节间所有部位皮层中的硅化物均是由有机硅化物和无机硅化物组成;无机硅化物的含量约为有机硅化物的3倍,且种类更复杂;节间上部皮层的硅化物含量最高,下部皮层的硅化物含量最低;自外至里,上部皮层中硅化物的含量、分布具有与其他禾本科原料皮层相似的规律性,下部皮层的规律性较差。不同硅化物的碱稳定性有差别;部分无机硅化物微块由于其连接机构的碱溶解而脱落,完好地存在于黑液之中。在皮层生物结构中,硅化物的堆砌、连接方式及其碱溶机理有待进一步研究。The content and components of silicides in the cuticle of the up-part,the mid-part and the low-part on the internode of wheat straw stem were studied by means of XPS,and the alkali-stability of the silicides in the foresaid cuticle was also investigated.The results showed that,the silicides in above cuticles are all composed of organic and inorganic silicides.The content of inorganic silicides is about three times as high as organic silicides.And the sorts of inorganic silicides are more complex.Among the above three parts,the up-part has highest silicide content,and the low-part the lowest.From the outside to the inner of the cuticle,the profile of silicide content is in analogy to that of other gramieal cuticle,and the profile of silicides in the low-part cuticle has poor order.Under the experimental conditions,the alkali-stability of a sort of silicides is different from the other.A part of inorganic micro blocks of silicides with higher alkali-stability wholly remains in the black liquor after falling off from the cuticle.The mode of building and connecting as well as the alkali-degrading of the silici micro blocks will be further researched.国家自然科学基金(20277012)资助项

Study on the Silicides in Cuticle of Wheat Straw Stem by Means of XPS(Ⅰ)

进行麦秆皮层硅化物的XPS测定及分峰拟合分析。结果表明,麦秆不同部位皮层中的硅化物都是由有机硅化物和无机硅化物组成的。有机硅化物主要有线状P-METHylSIl、树脂P-PHEnylSIl、PH3SIOSIPH3、PH4SI、ET3SICl、ET2SICl2等。无机硅化物的种类更复杂,主要有硅灰石、云母、钠长石、硅线石、高岭土、分子筛A型及X型物质以及5种结晶形式的SIO2等。不同部位硅化物的组成、含量不同,将影响其在制浆等处理过程中的稳定性。The silicides in the cuticle of wheat straw stem were studied by means of XPS-peak-differenating analysis.The results showed that silicides in every part of the wheat straw stem are composed of two sorts of silicides,i.e.organic silicides and inorganic silicides.The main components of the organic silicides are P-MethylSil(linear),P-PhenylSil(resin),Ph3SiOSiPh3,Me3SiOSiMe3,Ph3SiSiPh3,Et3SiCl,Et2SiCl2 etc.The inorganic organic silicides are very complex,and the major sorts are Wollastonii,Mica,albite,Kaolinite,sillimanite,materials of Mol.Sieve A and X,SiO2(Vycor),SiO2(alpha cristobal),SiO2(guartz),H Zeoton etc.The components of silicides in different part's cuticle are different.国家自然科学基金(20277012)资助项