NSFGEO-NERC: An unexpected requirement for silicon in coccolithophore calcification: physiological, ecological and evolutionary implications

NSFGEO-NERC：颗石藻钙化过程中对硅的意外需求：生理、生态和进化影响

基本信息

批准号：
1638838
负责人：
Alison Taylor
金额：
$ 33.52万
依托单位：
University of North Carolina at Wilmington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1638838&HistoricalAwards=false
关键词：
NSFGEO NERC unexpected requirement silicon

项目摘要

Biomineralization by marine phytoplankton has had a profound impact on our planet. The production of special cell wall material, calcite coccoliths by coccolithophores and silica frustules by diatoms, are major drivers in global biogeochemical cycles, but the underlying cellular processes remain poorly understood. It is widely considered that calcification in coccolithophores occurs through a very different process to silicification in diatoms, however some ecologically important coccolithophore lineages possess diatom-like silicon (Si) transport systems and have an absolute requirement for Si during coccolith formation. Importantly, the abundant bloom-forming coccolithophores such as Emiliania huxleyi exhibit no requirement for Si. There is a clear need to understand how these different physiological requirements for dissolved Si have driven the ecology and evolution of the coccolithophores. The project will yield a more complete understanding of the Si requirements of coccolithophores, its role in the calcification process, and the impacts of Si availability on the biogeography of these important bloom forming phytoplankton. The results are expected to strengthen our ability to predict the responses of coccolithophores to short and long-term environmental change, and therefore the consequences for the marine biogeochemical cycles in which they participate. In addition to the scientific outcomes, the project provides independent research opportunities to a diverse pool of undergraduate students, provide interdisciplinary training for graduate students, and facilitate the professional development of post-doctoral researchers. Public engagement in the research is facilitated through participant involvement in regional science festivals, public outreach events, production of educational resources, and targeted K-12 summer camp activities.Calcification in coccolithophores appears to represent a distinct process from silicification in diatoms, another major group of biomineralized phytoplankton. The apparent absence of a requirement for silicon (Si) in coccolithophores has been proposed to play a critical role in their ability to out-compete the otherwise dominant diatoms in areas of low dissolved Si availability. However, the investigators recently demonstrated that some globally important coccolithophores possess diatom-like Si transporters and exhibit an obligate requirement for Si in the calcification process. This discovery has important implications both for phytoplankton ecology and for the evolution of biomineralization. Using a range of physiological, molecular and computational approaches the project will 1) Establish Si requirements of ecologically important coccolithophore groups; 2) Determine the physiological role of Si in coccolithophores; 3) Determine the evolutionary events leading to the differing requirements for Si in calcification; 4) Examine the ecological distribution of Si-requiring coccolithophores, and 5) Determine the impact of the Si requirement on coccolithophore ecology. This project therefore integrates the molecular identification of genes (Si transporters), the physiological role of these transporters, and ecosystem scale models in order to examine how the requirement for Si influences ecosystem functioning and coccolithophore biogeography. The results of this work provides essential data that describes the cellular mechanisms of calcification and the range of physiological diversity between major coccolithophore lineages. The research also explores a previously unforeseen aspect of phytoplankton ecology; examining how the differing requirements for Si in calcifying coccolithophores may have shaped competitive interactions with other phytoplankton over both contemporary and evolutionary timescales. Overall, the research provides novel insights into physiology, ecology and evolution of coccolithophores, including information on how and why coccoliths are produced, which is currently poorly understood. This information is vital in order to understand how coccolithophores have been influenced by past changes in the Earth's climate, and their potential responses to future oceans.

海洋浮游植物的生物矿化对我们的星球产生了深远的影响。在全球生物地球化学周期中，由硅藻菌和硅胶粉的方解石生产的特殊细胞壁材料（通过硅藻的有方解石的生产）是，但潜在的细胞过程仍然很少了解。人们普遍认为，在硅藻中的硅化过程发生了截然不同的过程，但是某些在生态上重要的coccolithophore谱系具有类似硅藻的硅（SI）传输系统，并且在球球石形成过程中对Si具有绝对要求。重要的是，诸如Emiliania huxleyi之类的丰富的花朵形成的可核岩石对Si没有任何要求。显然需要了解这些溶解的SI的这些不同的生理要求如何驱动了cocolithopholores的生态和进化。该项目将对Coccolithophores的SI需求，其在钙化过程中的作用以及SI可用性对这些重要开花形成浮游植物的生物地理学的影响。预计结果将增强我们预测cococolithomothores对短期和长期环境变化的反应的能力，因此，对海洋生物地球化学周期的后果产生的后果。除了科学成果外，该项目还为各种本科生提供了独立的研究机会，为研究生提供跨学科培训，并促进了博士后研究人员的专业发展。通过参与参与区域科学节，公共宣传活动，教育资源的生产以及针对性的K-12夏令营活动来促进对研究的公众参与。球虫的估计似乎代表了硅化的独特过程，与硅藻的硅化相关，这是另一个生物启动的Phytoplankton的主要群体。已经提出，明显没有对硅（SI）在球colo虫中的要求，这在其在低溶解的SI可用性领域竞争的能力方面发挥了关键作用。然而，研究人员最近证明，一些全球重要的球虫具有类似硅藻的Si转运蛋白，并且在钙化过程中表现出对SI的义务要求。这一发现对浮游植物生态学和生物矿化的演变都具有重要意义。使用一系列生理，分子和计算方法，项目将1）建立对生态重要的可核烷基组的SI要求； 2）确定Si在核岩石流体中的生理作用； 3）确定导致SI钙化需求不同的进化事件； 4）检查si征水的生态分布，以及5）确定SI需求对Coccolithophore生态学的影响。因此，该项目整合了基因（SI转运蛋白），这些转运蛋白的生理作用以及生态系统量表模型的分子鉴定，以便研究对SI的需求如何影响生态系统功能和Coccoccolithophore生物地理学。这项工作的结果提供了描述钙化的细胞机制以及主要的可核河流谱系之间的生理多样性范围的基本数据。该研究还探讨了浮游植物生态学的先前不可预见的方面。研究SI在钙化的钙化流量方面的不同要求如何在当代和进化时段与其他浮游植物的竞争相互作用。总体而言，这项研究提供了对生理学，生态和生态学进化的新见解，包括有关如何以及为什么产生生产的信息，目前知之甚少。这些信息对于了解地球气候过去变化及其对未来海洋的潜在反应如何影响了Coccolithophotors的影响至关重要。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

An Extracellular Polysaccharide-Rich Organic Layer Contributes to Organization of the Coccosphere in Coccolithophores

富含多糖的细胞外有机层有助于颗石藻中颗球的组织

DOI：
10.3389/fmars.2018.00306
发表时间：
2018
期刊：
Frontiers in Marine Science
影响因子：
3.7
作者：
Walker, Charlotte E.;Heath, Sarah;Salmon, Deborah L.;Smirnoff, Nicholas;Langer, Gerald;Taylor, Alison R.;Brownlee, Colin;Wheeler, Glen L.
通讯作者：
Wheeler, Glen L.

The Effect of cytoskeleton inhibitors on coccolith morphology in Coccolithus braarudii and Scyphosphaera apsteinii