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发布时间:2009/11/13   浏览次数:42427次

国际海洋研究科学委员会 “微型生物碳泵”工作组(SCOR WG134)

 Open Science Meeting 在厦召开

 

国际海洋研究科学委员会“微型生物碳泵”工作组(SCOR WG134)第一次会议的Open Science Meeting于2009年10月27-28日在厦门召开。会议的主题是Bridging Biology and Chemistry in Ocean Carbon Sequestration。

 

本次会议由厦门大学“长江学者”焦念志教授主持,与会者包括来自美国、法国、德国、加拿大、丹麦、西班牙、捷克、奥地利、印度、台湾、香港共12个国家和地区的海洋微型生物领域和海洋地球化学研究领域的20位专家及近百位国内同行。18位专家做了报告,IGBP、SCOR、厦门大学的相关领导出席了会议并致辞。

 

气候变暖主要是由人为活动造成的大气CO2增加所导致的,海洋是大气CO2的“汇”,此前已知的海洋储碳机制主要是基于颗粒有机碳的沉降机制的“生物泵”(Biological Pump,BP)和基于物理过程和化学平衡的“溶解度泵”(Solubility Pump,SP)。我们新提出的“微型生物碳泵(Microbial Carbon Pump, MCP)”是基于溶解有机碳而不是依赖于颗粒有机碳的机制,即活性溶解有机碳通过微型生物的利用、修饰、转化,并在一系列物理化学过程作用下形成惰性溶解有机碳长期储存在海洋中,起到海洋封存碳的作用。理论分析表明,与BP相比MCP储碳能力更强,特别是在河口和浅海,BP因受到再悬浮的影响而严重削弱的情况下,MCP发挥着不可替代的作用;与SP相比,MCP有不可比拟的优势:不存在化学平衡移动,不会导致海洋酸化。

 

“微型生物碳泵”是一个涵盖生物海洋学、地球化学等多学科的综合性理论框架,是一个多学科交叉的科学命题。这就需要不同领域的科学家携手合作、共同努力来架起一座跨学科的桥梁,从不同角度探讨MCP有关的海洋储碳过程与机制。本次会议聚集了生物海洋学和海洋地球化学领域的著名专家包括:美国Scripps海洋研究所的“杰出教授”Farooq Azam博士(海洋“微食物环”概念的提出者)、荷兰皇家海洋研究所的Gerhard Herndl教授(首次实测海洋古菌固碳能力并计算了海洋古菌固碳量)、美国迈阿密大学的Dennis Hansell教授(DOC专家、海洋地球化学)、德国Alfred Wegner 极地与海洋研究所的Gerhard Kattner教授(海洋有机分子结构)、台湾中山大学的Chen-Tung Arthur Chen教授(国际地圈生物圈计划科学指导委员会副主席)、德国奥丁堡大学海洋环境化学生物研究所的Meinhard Simon教授(微型生物与物质循环)、美国田纳西大学的Steven Wilhelm教授(海洋病毒)等。

 

会议主要报告内容:

 

Nianzhi Jiao 
The MCP is a conceptual framework intends to cover a broad multidisciplinary ground, and it seeks a synthesis for future research on the kinetic and mechanistic bases of DOC dynamics. We define this area of emphasis in terms of a set of new testable hypotheses related to DOC sources, sinks, spatial-temporal variability, and underlying biogeochemical mechanisms and consequences for the ocean's future biogeochemical state. The emphasis on the MCP should help better constrain the pools, fluxes and mechanisms in the oceanic carbon cycle. The MCP is a promising framework to formulate hypotheses and develop the necessary methodology to rapidly advance the field.

Dennis Hansell
Dissolved organic matter in seawater is the largest ocean reservoir of the reduced carbon. It is produced in the surface ocean, but overturn of the ocean water column exports DOM to depth, thus contributing to the biological pump whereby biogenic carbon is sequestered in the deep ocean. Dr. Hansell’s researches focused on the distributions of DOC in the global ocean scale, and results showed that DOC concentrations could be of great differences according to the seasons, the depths and the latitudes. Further researches need to be carried out for understanding more details about the role of microorganisms.

Meinhard Simon 
There is ample evidence today that the SAR11 and Roseobacter clades are prominent components of the bacterioplankton and play major roles in processing organic matter in marine surface waters. In order to better understand the processing and degradation of labile and refractory marine organic matter we need to have a better insight into the growth and functional response of these subgroups, the given environmental situation and the complexity of the DOM. 

Gerhard Herndl 
Prokaryotic autotrophy such as nitrifiers might represent a significant source of newly fixed organic carbon in the dark ocean. It is estimated that the mesopelagic chemoautotrophic carbon fixation amounts to about 20% of the export phytoplankton production. This "dark ocean’s primary production", albeit hitherto largely ignored, might stimulate the heterotrophic food web in the meso- and bathypelagic global ocean.

Steven W Wilhelm 
Viruses are pervasive elements in marine surface waters and impart significant mortality on marine microbial communities. Viruses effectively redistribute nutrient elements and carbon from large biological particles to biologically inactive particulate and dissolved pools of organic compounds. This presentation outlines the existing knowledge concerning the role of viruses in marine carbon cycle and the ongoing efforts and future directions needed to understand how viruses influence biological carbon cycling in marine surface waters.

Feng Chen 
Advances in genomics and community genomics have uncovered potential novel microbial functions in various marine microbial consortia. Some of these new microbial processes are important to the function of global ecosystem because they are related to energy and carbon cycles. We are now entering into the omics age where the functions of microbial ecosystems can be inferred from bioinformatics and functional genomics. The omics technologies can be used to explore the key metabolic pathways associated with the microbial carbon pump.

Zhili He 
GeoChip 3.0 Effects of elevated co2 on the soil microbial community Metabolic diversity of microbial communities of deep-sea hydrothermal vent.

Gerhard Kattner 
The main portion of DOM is refractory or recalcitrant, thus, sequestered carbon on very long time scales will not be remineralized back to co2 for thousands of years. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) enables us to determine the molecular elemental composition of thousands of DOM molecules. The extremely complex compositions may be a major reason that recalcitrant DOM is not or only slowly utilized by microorganisms.

Colin Stedmon 
Brief introduction to DOM fluorescence. DOM fluorescence provides a wealth of information on the sources, sinks and dynamics of DOM. Then introduce the applications to the study of DOM biogeochemistry and the use of PARAFAC (Parallel factor analysis).

Xosé Antón Álvarez-Salgado 
The transformation of labile LMW–DOM into refractory HMW–DOM by the marine microbial food web is a key component of the recently defined “microbial carbon pump” that occurs in ocean margins as well as in epi–, meso– and bathypelagic open ocean waters. Recent methodological advances have enabled us to trace this transformation on basis of the optical properties of DOM. The HMW–DOM from different marine ecosystems can be isolated by flow–cross ultra filtration and their optical properties can be used to trace their origin and biogeochemical transformations. Furthermore, these materials can be re–dissolved, inoculated with natural microbial assemblages, and incubated to study additional transformations.

Christian Tamburini 
Dr. Christian Tamburini presented his work focused on how the hydrostatic pressure influences the prokaryotic capacity to degrade organic matter, and to sustain their growth and life in the dark ocean. By using High Pressure apparatus to sample, retrieve, and incubate waters without any change of the pressure, they did various of experiments which indicate that deep-sea prokaryotes prefer to live and grow under high pressure environment.

Michal Koblížek     
We analyzed diel changes in bacteriochlorophyll to assess *in situ* turnover rates of aerobic anoxygenic phototrophs in the euphotic zone of major oceanic gyres in the Atlantic and Pacific Oceans. Using this approach we found that phototrophic bacteria in the Sargasso Sea, in the South Atlanticand in oligotrophic regions of the South Pacific grew at rate of about one division per day. In addition, bacterial phospholipid biosynthesis rate shows similar turnover rate for the broader bacterioplankton community. These results indicate that the bacterioplankton community in the upper oligotrophic oceans grows at a rate of about one division per day, which is almost an order of magnitude faster than current estimates. This suggests that bacteria and microbial loop play much more important role in the marine carbon cycling.

Chuanlun Zhang 
Gas hydrates are one of the largest pools of readily exchangeable carbon on the earth surface. Releases of the greenhouse gas methane from hydrates are responsible for a number of important climate changes in geological history. Here we propose a molecular fossil proxy “Methane Index (MI)” which is constructed by the relative distribution of glycerol dialkyl glycerol tetraethers (GDGTs), the core membrane lipids of Archaea. This index can help us better document the destabilization of marine gas hydrates.

Chen-Tung Arthur Chen 
The South China Sea also exports DOC to the Philippine Sea, but here the export in the intermediate layer (350-1350m) is important.

Minhan Dai 
About “Continental Shelf Pump”--CSP is believed to occur where the solubility and biological pumps interact with a local hydrography that feeds dense water from the shelf floor into sub-surface (at least subthermocline) waters in the neighbouring deep ocean. Case study: South China Sea and East China Sea.

Nagappa Ramaiah 
Spatio-temporal variations in Heterotrophic bacteria (Hbac) abundance and production in central and eastern Arabian Sea; central and western Bay of Bengal and the equatorial Indian Ocean were described. In the overall, there are wide spatio-temporal differences in Hbac carbon biomass in the Arabian Sea. The Hbac abundance and production (BP) are the largest during the periods of low chlorophyll a concentrations and primary production (PP) and vice versa.

Hongbin Liu 
Prof. Liu showed work of phytoplankton growth in surface ocean and found their growth rate and grazing rate were controlled by temperature and mean cell size.

Yongfu Xu 
Dr. Yongfu Xu demonstrated a surface ocean carbon cycling model to us. This model incorporated perturbation and biogeochemical mechanisms
.

本次会议在被誉为海上花园的厦门举办,会议展示了厦门海洋科学的品味,同时厦门国际海洋周将其纳入高端学术论坛。会议的举办得到了国际SCOR、中国SCOR、厦门大学、近海海洋环境科学国家重点实验室以及厦门市的支持。

 

                                      会议代表合影
 

           厦门大学副校长致辞                           中国SCOR主席致辞

              IGBP副主席致辞                 近海海洋环境科学国家重点实验室主任致辞

专家报告

 

 

 

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