EES Departmental Seminar - Nina Golombek, Graduate Student Symposium

Title: Preservation of N isotope signals during sinking and sedimentation of organic material

Nina Y. Golombek
Ph.D. Candidate
Department of Earth and Environmental Sciences, Dalhousie University

Abstract: Understanding the biogeochemical transformations that particulate organic matter (POM) undergoes from production in surface waters to deposition on the seafloor is fundamental for interpreting the paleoceanographic record preserved in sediments. Here I will present results using compound-specific N isotope analysis of amino acids (δ15NAA) as a proxy to investigate the modification and preservation of POM during its passage through and residence in a benthic nepheloid layer (BNL) in the Gulf of Maine before ultimate sedimentation. This work opens potentially important questions for our current understanding of benthic-pelagic coupling and interpretations of proxy δ15N records in BNL-influenced areas. I will then present results that expand this work to marine surface sediments from other locations along the northwest Atlantic margin and other ocean regions globally. Finally, I will present initial results from a two-year experiment to test how formalin, a common preservation medium, affects bulk and amino acid-specific δ15N.

Fig. 1: Bathymetry map of the Gulf of Maine and western Scotian Shelf with ocean currents and sampling locations.

Biography: Nina received her B.Sc. in Geosciences and M.Sc. in Geology from University of Potsdam in 2017 and 2019, respectively, in cooperation with the German Research Centre for Geosciences (GFZ) working on oxidation of organic carbon during floodplain storage and fluvial transport. Her master’s thesis focused on seasonal variations in organic carbon export and changes in isotopic signatures. She studied and gained lab experience at UCL in London during her ERAMSMUS+ semester working in the Bloomsbury Environmental Isotope Facility as well as during her research assistantship at the AWI Potsdam - Helmholtz Centre for Polar and Marine Research. After her graduation, she joined the Sherwood lab to pursue her PhD in Earth Sciences in cooperation with the Oceanography department. Her thesis research focuses on compound-specific nitrogen isotope analysis of amino acids in sediment traps and sediments cores in the Scotian Shelf and Gulf of Maine region to provide new insights on nitrogen isotope preservation from time of production through sinking and ultimate burial.




Format: In person
Milligan Room, 8th floor Biology/Earth Sciences Wing of LSC

To join seminar via Zoom:
Meeting ID: 841 6754 5380
Passcode: 749063