Quantifying biogeochemical links between land and ocean: closing a major gap in the global carbon cycle

每年，陆地生态系统吸收的碳有很大一部分以溶解和颗粒有机物的形式出口到河流系统；仅英国陆地每年就出口约2千吨碳。其中只有一小部分被认为到达了开阔的海洋，但我们对陆地-海洋连续体中有机物在哪里、如何以及何时丢失的理解仍然不完整。这妨碍了我们理解不断变化的土地管理战略和气候变化将如何影响陆源有机物的命运，从而影响全球生物地球化学循环。我们寻找一个对沿着陆地-海洋连续体研究生物地球化学循环感兴趣的高度积极的学生，这是一个令人兴奋的新兴研究领域。该项目将结合新的孵化实验和最先进的稳定同位素技术，量化一年中不同时间在不同地点从源头溪流到沿海海域的陆源有机物的生物清除情况。它还将调查生物可利用溶解有机物出口的增加如何影响生物非活性碳的命运，即所谓的“引发效应”。该项目的成果将有助于为地球系统模型和气专委未来评估的发展提供信息。

Each year a significant fraction of all the carbon taken up by terrestrial ecosystems is exported to fluvial systems as dissolved and particulate organic matter; approximately 2 Gt of carbon are exported annually from the UK landmass alone. Only a fraction of this is thought to reach the open ocean, but our understanding of where, how and when organic matter is lost along the land-ocean continuum remains incomplete. This hampers our ability to understand how changing land management strategies and climate change will influence the fate of terrigenous organic matter and hence global biogeochemical cycles. We seek a highly motivated student that is interested in studying biogeochemical cycling along the land-ocean continuum, an exciting and emerging area of research. This project will combine novel incubation experiments and state-of-the-art stable isotope techniques to quantify the biological removal of terrigenous organic matter in contrasting locations, from headwater streams to coastal seas, at different times of the year. It will also investigate how an increase in the export of bioavailable dissolved organic matter influences the fate of biological unreactive carbon, so-called "priming effects". The outcome of this project will help inform Earth System Models and the development of future IPCC assessments.