Unraveling oceanic multi-element cycles using single cell ionomics

海洋元素循环受到海洋微生物，包括浮游植物的强烈影响。虽然人们早就认识到微生物的元素组成是这些循环的关键决定因素，但分析局限性意味着目前的理解通常是基于对混合群落中有限数量元素的平均观察。因此，缺乏对个人和群体水平上潜在的重要异质性的理解，以及对多元素循环的更全面的理解。因此，单生物/细胞分析是一个快速发展的领域，但许多技术受到低通量的阻碍。我们的目标是应用一种新的分析工具（飞行时间电感耦合等离子体质谱仪，ToF-ICPMS），以促进快速多元素分析的个别海洋浮游植物细胞和潜在的更高的营养水平。该项目将侧重于关键问题的变化（共）限制养分的可用性如何影响非限制性养分的多元素细胞组成，这对理解耦合养分循环有重大影响。虽然这个问题已经解决了在特定情况下的元素，元素的基础上，我们缺乏真正的多元素（“经济学”）的治疗，这也说明了混合自然群落的异质性。因此，该项目将有助于更深入地了解多元素海洋地球化学循环。

Oceanic elemental cycles are strongly influenced by marine microbes, including phytoplankton. Although it has long been recognised that the elemental composition of microbes is a key determinant of these cycles, analytical limitations mean current understanding is typically based on observations of limited numbers of elements averaged across mixed communities. Appreciation of potentially important heterogeneities at individual and population levels and a more holistic understanding of multi-element cycling is thus lacking. Consequently, single-organism/cell analysis is a fast-growing field, but many techniques are hampered by low throughput. We aim to apply a new analytical tool (Time of Flight Inductively Coupled Plasma Mass Spectrometry, ToF-ICPMS) to facilitate rapid multi-element analysis of individual marine phytoplankton cells and potentially higher trophic levels. This project will focus on the key question of how variability in (co-)limiting nutrient availability influences the multi-elemental cellular composition of non-limiting nutrients, which has significant consequences for understanding coupled nutrient cycling. Although this problem has been addressed in specific cases on an element-by-element basis, we lack true multi-element ('ionomic') treatments, which also account for the heterogeneity of mixed natural communities. The project will thus facilitate a deeper understanding of multi-elemental ocean biogeochemical cycles.