Unravelling the transformation pathways and fate of dissolved organic carbon and nitrogen in shallow coastal sediments

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Project Team: Joanne Oakes

Background/Summary

Humans are modifying global carbon and nitrogen cycles at an alarming rate. To understand the potential impacts of these changes, it is important to understand all components of carbon (C) and nitrogen (N) cycles. The world's oceans are a major reservoir for C and N, with a large fraction represented by dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Rivers and estuaries are a major source of DOC and DON to the ocean. The form and quantity of oceanic DOC and DON is therefore largely determined by shallow coastal sediments, which intercept riverine and estuarine inputs. However, the way in which DON and DOC-derived carbon and nitrogen is transformed within these sediments, and its ultimate fate, is unknown. This represents a significant gap in our understanding of global carbon and nitrogen cycles. This project aims to use a novel combination of techniques (isotope tracers, novel analysis methods, and modelling) to unravel the transformation pathways and ultimate fate of DOC and DON in shallow coastal sediments. This will provide an unprecedented understanding of coastal DOC and DON processing, a potentially major, but overlooked, part of global C and N cycling.