The Peru Margin is one of the most productive upwelling zones on earth. Much of what we know about the nitrogen cycle on the glacial-interglacial timescale was developed using sediments deposited in upwelling zones.
My work has focused on the processes controlling organic matter preservation and the fidelity of nitrogen isotopic composition of bulk sediments. Here I have demonstrated that movement of organic matter downslope by the action of the Peru Undercurrent results in significant degradation of organic matter and alteration of nitrogen isotopic signatures.
Compound specific nitrogen isotope analyses on chlorophyll derivatives demonstrate little change in isotopic composition whereas bulk isotope values change significantly. I have also found that despite significant chlorophyll degradation downslope, the chlorophyll nitrogen isotope values do not change. This type of study is very important observation to gain a better understanding of the processes that impact more ancient settings.
