Exopolymer Production by Benthic Diatoms: Rhythms, Responses and Acclimation to Environmental Stress

底栖硅藻的胞外聚合物生产：对环境压力的节律、反应和适应

• 批准号: 0110875
• 负责人: Michael Gretz
• 金额: $ 37万
• 依托单位: Michigan Technological University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0110875&HistoricalAwards=false
• 关键词: Exopolymer; Production; Benthic; Diatoms; Rhythms

0110875Michael Gretz & Graham UnderwoodThe diatoms are among the most important primary producers in the global environment. These single-cell algae are exceedingly abundant and among the most numerous aquatic organisms. The diatoms are major contributors to the base of the marine food chain, upon which economically important marine fisheries and ecologically significant marine mammal and bird populations are dependent. Oceans occupy approximately 70% of our planet and marine microalgae, of which diatoms are a predominant component, exert a powerful influence on today's atmospheric chemistry (they are the primary oxygen producers on earth) and the biogeochemical cycling of carbon and other elements. Hundreds of millions of years of past algal growth has contributed to the important petroleum deposits upon which our modern society depends. Diatoms, both in terms of the organisms themselves and the material they secrete, are of fundamental importance to overall aquatic ecology. Much of the carbon that diatoms fix is secreted in the form of extracellular polymers. These exopolymeric substances (EPS) strongly influence biogeochemical cycling in ecosystems, as they are contributors to the sediment carbon pool, important in food chains and the biostabilization of sediments. This research will characterize the production rates, composition and characteristics of diatom EPS produced by benthic diatoms under various environmental conditions (nutrient limitation, damaging irradiance levels, salinity stress). The composition and structure of different EPS will influence the role such molecules play in the environment. EPS characteristics will be correlated with the changing microenvironment within estuarine diatom biofilms, and with the response of the organisms to important environmental stresses. This information is required to define how diatoms acclimate to the changing conditions within intertidal biofilms and to determine the nature of the different EPS produced, which will lead to further studies of the role of EPS within intertidal biofilms. This work will greatly advance our knowledge of EPS and the physiological conditions in nature that trigger production of different types and may lead to advances in stabilizing sediments or identifying new polymers of commercial interest. In addition, this project will provide a valuable contribution to student training by engaging students in a multidisciplinary effort that involves integrated international cooperation between laboratories in the U.S. and the U.K.

0110875Michael Gretz 和 Graham Underwood 硅藻是全球环境中最重要的初级生产者之一。这些单细胞藻类数量极其丰富，是数量最多的水生生物之一。硅藻是海洋食物链基础的主要贡献者，具有重要经济意义的海洋渔业和具有重要生态意义的海洋哺乳动物和鸟类种群都依赖于该食物链。海洋占据了地球约 70% 的面积，海洋微藻（其中硅藻是主要成分）对当今的大气化学（它们是地球上的主要氧气生产者）以及碳和其他元素的生物地球化学循环产生了强大的影响。过去数亿年的藻类生长为我们现代社会赖以生存的重要石油矿床做出了贡献。硅藻，无论是生物体本身还是它们分泌的物质，对整个水生生态都至关重要。硅藻固定的大部分碳以细胞外聚合物的形式分泌。这些胞外聚合物物质（EPS）强烈影响生态系统中的生物地球化学循环，因为它们是沉积物碳库的贡献者，在食物链和沉积物的生物稳定性中很重要。本研究将表征底栖硅藻在各种环境条件（营养限制、破坏性辐照度水平、盐度胁迫）下产生的硅藻 EPS 的生产率、成分和特征。不同EPS的组成和结构会影响这些分子在环境中发挥的作用。 EPS特性将与河口硅藻生物膜内不断变化的微环境以及生物体对重要环境胁迫的反应相关。需要这些信息来定义硅藻如何适应潮间带生物膜内不断变化的条件，并确定所产生的不同 EPS 的性质，这将导致进一步研究 EPS 在潮间带生物膜中的作用。这项工作将极大地增进我们对 EPS 和自然界中触发不同类型生产的生理条件的了解，并可能导致稳定沉积物或识别具有商业利益的新聚合物方面的进展。此外，该项目还将通过让学生参与涉及美国和英国实验室之间综合国际合作的多学科努力，为学生培训做出宝贵贡献。