Nitrogen isotopes in the palynomorph Tasmanites, as an indicator of climate change

Abstract

The stable nitrogen isotope signature (δ15N) of plants and animals preserved in sedimentary rocks retain a record of past oceanic and atmospheric chemical changes. The majority of modem nitrogen isotope studies focus primarily on the interpretation of total nitrogen from bulk sedimentary marine samples. This technique is fraught with uncertainty because bulk samples often contain large quantities of inorganic nitrogen and considerable variation in the organic fraction. Furthermore, diagenesis can have a greater impact on the sinking flux of organic material in different areas of the ocean, leading to additional uncertainty in the data extracted from bulk samples.