Ecological studies on Prochlorococcus in China seas

Prochlorococcus, a tiny oxygenic photosynthetic picoplankton with unique pigment composition, has been found to be ubiquitous and abundant in the world oceans, and has been recognized to be closely related to living resources and environmental issues. It has attracted the interest of marine biologists since its discovery, and field data on it over global oceans have accumulated rapidly in the past 10 years. In China, we have studied Prochlorococcus for 8 years, achieving a basic ecological understanding. The presence of Prochlorococcus in China seas, marginal seas of the west Pacific, was confirmed, and its distribution patterns were also brought to light. Prochlorococcus is very abundant in the South China Sea and the offshore regions of the East China Sea. It is seasonally present in the southeast part of the Yellow Sea and absent in the Bohai Sea. Temporal and spatial variations of the abundance of Prochlorococcus and their affecting factors, physiological and ecological characteristics of Prochlorococcus and their relationships to the other groups of picoplankton, and the importance of Prochlorococcus in total biomass and possible roles in living resources and environmental problems are discussed. In the future, isolation of different Prochlorococcus strains from the China seas and their physiological characteristics, genetic diversity, phylogenies and gene exploiture, etc. are important issues to be addressed

Proteorhodopsin - A new path for biological utilization of light energy in the sea

The breakthrough of environmental genomics of marine microbes has revealed the existence of eubacterial rhodopsin in the sea, named proteorhodopsin (PR), which can take light to produce bio-energy for cell metabolism. Gene and protein sequence analysis and laser flash-induced photolysis experiments have validated the function of PR as light-driven proton-pump. During the pumping process, light energy is transformed into chemical gradient potential across plasma inner-membrane, the potential energy is then used to synthesize ATR The finding of PR actually brings to light a novel pathway of sunlight utilization existing in heterotrophic eubacteria in contrast to the well-known chlorophyll-dependent photosynthesis in the sea. Since the group of PR-bearing bacteria is one of the numerically richest microorganisms on the Earth, accounting for 13% of the total in sea surface water, and with averaged cellular PR molecules of 2.5x10(4), PR-bearing bacteria are a key component not to be ignored in energy metabolism and carbon cycling in the sea. Based on the understanding of current literature and our own investigation on PR in the China seas which indicated a ubiquitous presence and high diversity of PR in all the marine environments, we propose a conceptual model of energy flow and carbon cycling driven by both pigment-dependent and -independent biological utilization of light in the ocean

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海岸带是地球表层系统陆海相互作用最强烈、人类活动压力最大、气候变化最敏感的动态而复杂的人文-自然系统。自然和人为双重压力持续改变着海岸带的地形地貌、人口资源、生态环境和文化遗址,甚至引发各种灾害。与此同时,人们在利用海岸带资源过程中,尚未建立在科学认识海岸带规律的基础上,因而难以陆海统筹并协调平

海洋固碳与储碳——并论微型生物在其中的重要作用

气候变化受到全球关注,大气CO2含量与气候变化息息相关.海洋是地球上最大的活跃碳库,在气候变化中扮演着举足轻重的作用,一个根本的机制就是生物固碳.然而,海洋浮游植物光合固碳量远远大于海洋调节大气CO2的能力和容量.本文指出,“固碳“不等于“储碳“,只有长期储存在海洋中的那部分碳才能对气候变化起到调节作用.但已知的海洋储碳机制(包括依赖于理化过程的“溶解度泵“以及依赖于颗粒有机碳沉降的“生物泵“等)并不能解释海洋碳汇有关的若干现象和问题.究其原因,还在于没有认识占海洋总有机碳90%以上的溶解有机碳(dOC)的形成机制.在对上述问题分析的基础上论述了基于微型生物对dOC转化并形成惰性dOC(rdOC)的微型生物碳泵(MICrObIAl CArbOn PuMP,MCP)储碳机制、探讨了海洋碳汇研发所面临的挑战及前景.国家重点基础研究发展计划重大科学研究计划项目(编号:2013CB955700);国家自然科学基金重大计划(批准号:91028001);国家海洋公益性行业科研专项(编号:201105021)资

微生物碳泵理论揭开深海碳库跨世纪之谜的面纱

深海碳库成因之谜气候变化是当今最大的全球性环境问题。人类活动导致大气二氧化碳（CO2）持续升高是加剧气候变化的主因。海洋是地球上最大的碳库,吸收了工业革命以来人类活动排放CO2的三分之一,是全球气候变化的"调节器"。海洋碳库调节气候变化的主要组分是溶解在水里的有机碳（DOC）。一方面,海洋DOC总碳量与大气碳库相近

Nitrate assimilation by marine heterotrophic bacteria

硝酸盐同化是指把硝酸盐还原分解并最终合成自身所需的有机氮的过程.最近基于分子生物学的手段研究发现异养细菌的硝酸盐同化基因(nas A)普遍存在于海洋水体和沉积物中.比较基因组学揭示了硝酸盐同化系统的基因排列存在种间差别,基因调节系统具有多样性.对这类微生物及其作用过程进行系统的分析和总结不但有助于充分认识硝酸盐同化过程及其生态意义,更能深入了解异养细菌在氮循环过程中的重要作用.本文结合作者的工作,集中总结和讨论异养细菌同化硝酸盐有关的研究进展,认识异养细菌硝酸还原作用的具体过程及其生态意义,对未来该领域的研究起到引导作用.国家重点基础研究发展计划项目(编号:2013CB955700)资

Molecular ecology studies of marine Synechococcus

Cyanobacteria of the genus Synechococcus is a dominant component of microbial community in the world's oceans, and is a major contributor to marine primary productivity and thus plays an important role in carbon cycling in the oceans. Besides the ecological importance, the cultivability also made Synechococcus a very special group of marine microorganisms, which has attracted great attention from oceanographers and biologists. Great progress in the physiology, biochemistry and phylogeny of Synechococcus has been made since its discovery. We here review the current status of molecular ecology of marine Synechococcus and give a perspective into the future based on our understanding of the literature and our own work

海洋原绿球藻对环境的适应机制

原绿球藻是贫营养大洋的优势自养类群,是目前已知最小的原核类光合自养生物,广泛分布于南北纬40°之间、从表层到真光层底部近200M的水层.新近分子生物学研究发现,原绿球藻可以划分出适应不同水层、不同环境的多种生态型.不同的生态型在光利用、营养盐利用方面的特点均有不同.文中从分子生物学视角出发,探讨了原绿球藻对光、营养盐的适应机制,并分析了原绿球藻基因组学特征.科技部资助项目(2007CB815904);国家自然科学基金(40632013);海洋局项目(200805068)资

聚球藻(Synechococcus)分子生态学研究进展

蓝细菌聚球藻 (Synechococcus)是海洋浮游植物群落的优势组分 ,是全球碳循环的主要参与者和初级生产力的主要贡献者 ,在海洋生态系统的光合作用、碳循环及食物链中扮演着举足轻重的角色 .由于聚球藻在海洋生态系统中占有重要地位并且是少数几个可培养代表性海洋微型生物之一 ,自从它被发现以来一直是人们研究的热点 .目前 ,在聚球藻的生理、生化及系统发育研究等方面取得了一系列重要进展 .在综述聚球藻分子生态学研究进展的基础上 ,分析了目前的研究现状 ,并结合作者的工作实践对未来的研究进行了展望 .国家自然科学基金(批准号:40176037,30170189,40232021);; 国家重点基础研究发展规划(批准号:G200078500);; 中国博士后自然科学基金资助项