Collaborative Research: Do Cyanobacteria Drive Marine Hydrocarbon Biogeochemistry?

虽然向海洋中释放石油碳氢化合物被认为是一种环境和人类危害，但最近的一项研究估计，在每年的基础上，单个浮游植物群体(蓝藻)释放的天然碳氢化合物对表层海洋的总碳氢化合物贡献至少是十倍以上。该项目将首次深入研究这一巨大的生物碳氢化合物池的潜在生物地球化学循环。通过实地研究、实验室蓝藻培养和最先进的化学分析，研究人员将研究这一主要海洋碳氢化合物池的分子结构、产生和去除的速度和机制，以及控制其循环的环境条件。这项研究的结果将揭示重要的新知识，有助于更好地理解海洋中的一个主要碳循环。此外，数据可表明蓝藻碳氢化合物在准备天然海洋细菌以应对和降解石油泄漏方面的作用，以及碳氢化合物储藏某些成分的海气交换可能造成的大气影响(例如，云的形成)。该项目将支持本科生和研究生、一名博士后研究员和一名新的教员，并将吸引加州和北卡罗来纳州少数族裔服务机构的参与者。还计划与石油泄漏和生物燃料研究人员建立联系，以评估这项研究产生的数据的更多实际应用。最近报告的蓝藻每年生产3.08亿-7.71亿吨碳氢化合物，是从泄漏和天然渗漏输入的海洋石油碳氢化合物的10倍。因此，这些生物碳氢化合物几乎肯定会对海洋中的碳循环和细菌群落组成产生重大影响，但从来不是严格研究的对象。该项目将调查海洋中生物碳氢化合物的分布、分配和循环，重点是生物碳氢化合物的丰度和分子多样性与蓝藻种群的关系；挥发到大气中的生物碳氢化合物充当生物碳氢化合物汇的程度；以及碳氢化合物由蓝藻产生和由碳氢化合物降解菌消耗的速率。对浮游植物群落结构和丰度的自然梯度的实地研究将使用最先进的化学分析来评估生物碳氢化合物的分布，并将与培养实验一起确定生物来源碳氢化合物在表层海洋中循环的定量速率。实验室研究将通过在严格控制的实验室条件下评估碳氢化合物的产生和损失机制来加强实地研究。总而言之，该项目将对海洋碳循环的这一重要组成部分有一个定量的了解。

While the release of petroleum hydrocarbons into the ocean is recognized as an environmental and human hazard, a recent study has estimated that on an annual basis, the release of natural hydrocarbons by a single phytoplankton group (cyanobacteria) contributes at least ten times more total hydrocarbon to the surface ocean. This project will be the first in-depth study of the latent biogeochemical cycling of this huge pool of biogenic hydrocarbons. Using field studies, laboratory incubations of cyanobacteria, and state-of-the art chemical analysis, the researchers will examine the molecular structures, rates and mechanisms of production and removal, and the environmental conditions that control the cycling of this major pool of oceanic hydrocarbons. The results of this study will reveal significant new knowledge for improved understanding of a major carbon cycle in the ocean. Additionally, data could indicate a role for cyanobacterial hydrocarbons in preparing natural marine bacteria to respond to, and degrade petroleum spills, as well as a possible atmospheric impact (e.g. cloud formation) resulting from air-sea exchange of certain components of the hydrocarbon pool. This project will support undergraduate and graduate students, a postdoctoral investigator, and a new faculty member, and will engage participants from minority-serving institutions in California and North Carolina. Plans are also included to establish links with oil spill and biofuel researchers in order to evaluate additional practical applications for the data resulting from this study.The annual production of 308,000,000 - 771,000,000 tons of hydrocarbons by cyanobacteria has recently been reported and is a factor of 10 larger than marine petroleum hydrocarbon input from spills and natural seeps. Consequently, these biogenic hydrocarbons almost certainly have significant implications for the carbon cycle and the bacterial community composition in the ocean but have never been the subject of rigorous study. This project will investigate the distribution, partitioning, and cycling of biogenic hydrocarbons in the ocean, focusing on the abundance and molecular diversity of biogenic hydrocarbons in relation to cyanobacterial populations; the extent to which volatilization to the atmosphere acts as a sink for biogenic hydrocarbons; and the rate at which hydrocarbons are produced by cyanobacteria and consumed by hydrocarbon-degrading bacteria. Field studies across natural gradients in phytoplankton community structure and abundance will employ state of the art chemical analysis to evaluate the distribution of biogenic hydrocarbons, and together with incubation experiments will determine quantitative rates for biogenic hydrocarbons cycling in the surface ocean. Laboratory studies will augment field studies by assessing hydrocarbon production and loss mechanisms under carefully controlled laboratory conditions. Together, the project will obtain a quantitative understanding of this important component of the oceanic carbon cycle.