Controls on and paleoceanographic utility of the valve size frequency distribution of the Southern Ocean diatom, Fragilariopsis kerguelensis

通过开发碳或硅循环的古海洋学替代物，将有助于揭示南大洋生物泵在调节气候方面的作用。硅藻，Fragilariopsis kerguelensis，阀门的平均大小随季节变化，纬度，并在南大洋的冰川-间冰期周期的观察表明，沉积物中的阀门大小的频率分布可用于重建方面的古生产力和硅循环。我们的目标是开发这个代理使用文化，现场和沉积物样品，以确定阀门大小的频率分布，其中最重要的是可能是人口内的孢子形成的频率的确切控制。对孢子形成的控制是未知的，无论是在文化中的交配实验，以及在原位铁施肥实验很可能解开的机制，确定孢子形成控制和现场条件下。然后，阀大小频率分布可用于指示触发孢子缺陷形成的环境和/或生物条件的强度。

Unraveling the role of the Southern Ocean's biological pump in regulating climate would be enhanced by the development of paleoceanographic proxies specific to carbon or silica cycling. Observations that the average size of valves of the diatom, Fragilariopsis kerguelensis, varies seasonally, with latitude, and over glacial-interglacial cycles in the Southern Ocean suggest that the valve size frequency distribution in sediments could be used to reconstruct aspects of paleoproductivity and silica cycling. We aim to develop this proxy by using culture, field and sediment samples to determine the exact controls on valve size frequency distributions, the most important of which is likely to be the frequency of auxospore formation within the population. The controls on auxospore formation are as yet unknown and both mating experiments in culture as well as in situ iron fertilization experiments are likely to unravel the mechanisms determining auxospore formation under both controlled and field conditions. The valve size frequency distribution can then be used to indicate the intensity of the environmental and/or biological conditions triggering auxospore formation.