Applications of compound-specific radiocarbon analysis for the study of sedimentation processes and carbon cycling in marine sediments
Organic matter burial in marine sediments is an important long-term sink of carbon out of the active reservoirs of the carbon cycle. Marine sediments thus represent a valuable archive of information concerning the ocean and its role in the carbon sequestration. Processes and budgets of organic carbon burial have been the subject of many studies of past climates.
Total organic matter in marine sediments, however, consists of a complex mixture of materials deriving from a wide range of sources. For the understanding of carbon cycling it is necessary to know the time of carbon fixation, the duration of storage in reservoirs and the timescales of transport and degradation of organic matter.
Compound-specific radiocarbon (14C) dating provides a valuable tool for the understanding of sedimentation processes, delivery mechanisms and turnover rates. By use of molecular-level 14C data it is possible to identify compounds that have experienced redistribution processes, gain information about their duration, estimate residence times and characterize carbon sources.
14C studies of source-specific biomarkers have revealed that different components isolated from marine sediments can exhibit a wide spectrum of apparent ages, ranging from “modern” to several thousand years in surface sediments. The goal of this research project is to study the sedimentary and diagenetic processes resulting in the observed complex age structure of organic matter in marine sediments and to answer the following questions:
- How does preferential degradation affect the radiocarbon age of different organic biomarkers preserved in the sediment?