Holocene records of chlorin N isotopes

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doi: 10.1180/minmag.2013.077.5.8
Author(s): Higgins, Meytal B.; Robinson, Rebecca S.; Pearson, Ann
Author Affiliation(s): Primary:
Princeton University, Department of Geosciences, Princeton, NJ, United States
Other:
University of Rhode Island, United States
Harvard University, United States
Volume Title: Goldschmidt abstracts 2013
Source: Mineralogical Magazine, 77(5), p.1299; Goldschmidt 2013, Florence, Italy, Aug. 25-30, 2013. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0026-461X CODEN: MNLMBB
Note: In English
Summary: Nitrogen isotope ratios measured in sedimentary chlorophyll degradation products provide a diagenetically unaltered signal of the marine nitrogen cycle during deposition. Additionally, due to taxonomic differences in fractionation associated with chlorophyll biosynthesis, these records can be used to reconstruct the cyanobacterial contribution to buried organic matter. If diazotrophic cyanobacterial contribution to biomass increases during enhanced N2 fixation, then chlorin N isotope records may provide an additional constraint on the importance of this source of N to surface waters in the geologic past. We reconstructed low resolution records of chlorin δ15N values from the last glacial maximum to recent sediments in four oceanographically distinct settings. Samples were taken from ODP sites 1234 (Chile Margin), 1237 (Nazca Ridge, Peru), 1063 (Bermuda Rise), and core 17964 from the South China Sea. These four globally-distributed sites represent different nutrient regimes characterized by a wide range of modern P* values and potential rates of N2 fixation. Chlorin δ15N data were compared to new or previously published bulk N data to examine for diagenetic enrichment of bulk N (causing 15N offsets to increase) or cyaobacterial contribution to export (causing 15N offsets to decrease). Preliminary data show an average δ15N offset of ∼5-5.5ppm between bulk and chlorin N at all sites, suggesting predominantly algal export production irrespective of N2 fixation regime and bulk values of δ15N.
Year of Publication: 2013
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Bermuda Rise; Biogenic processes; Cenozoic; Chlorophyll; Cyanobacteria; Degradation; Diagenesis; East Pacific; Fixation; Holocene; Isotope ratios; Isotopes; Leg 172; Leg 202; N-15/N-14; Nazca Ridge; Nitrogen; North Atlantic; ODP Site 1063; ODP Site 1234; ODP Site 1237; Ocean Drilling Program; Organic compounds; Pacific Ocean; Pigments; Porphyrins; Quaternary; South Pacific; Southeast Pacific; Stable isotopes
Coordinates: S361300 S361300 W0734100 W0734100
N334111 N334111 W0573654 W0573654
S160000 S160000 W0762300 W0762300
Record ID: 2014025276
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland
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100 1 |a Higgins, Meytal B.  |u Princeton University, Department of Geosciences, Princeton, NJ 
245 1 0 |a Holocene records of chlorin N isotopes 
300 |a p. 1299 
500 |a In English 
500 |a Research program: ODP Ocean Drilling Program 
500 |a Affiliation: Princeton University, Department of Geosciences; Princeton, NJ; USA; United States 
500 |a Affiliation: University of Rhode Island; ; USA; United States 
500 |a Affiliation: Harvard University; ; USA; United States 
500 |a Source note: Mineralogical Magazine, 77(5), p.1299; Goldschmidt 2013, Florence, Italy, Aug. 25-30, 2013. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0026-461X 
500 |a Publication type: conference paper or compendium article 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland 
520 |a Nitrogen isotope ratios measured in sedimentary chlorophyll degradation products provide a diagenetically unaltered signal of the marine nitrogen cycle during deposition. Additionally, due to taxonomic differences in fractionation associated with chlorophyll biosynthesis, these records can be used to reconstruct the cyanobacterial contribution to buried organic matter. If diazotrophic cyanobacterial contribution to biomass increases during enhanced N<2` fixation, then chlorin N isotope records may provide an additional constraint on the importance of this source of N to surface waters in the geologic past. We reconstructed low resolution records of chlorin δ>15`N values from the last glacial maximum to recent sediments in four oceanographically distinct settings. Samples were taken from ODP sites 1234 (Chile Margin), 1237 (Nazca Ridge, Peru), 1063 (Bermuda Rise), and core 17964 from the South China Sea. These four globally-distributed sites represent different nutrient regimes characterized by a wide range of modern P* values and potential rates of N<2` fixation. Chlorin δ>15`N data were compared to new or previously published bulk N data to examine for diagenetic enrichment of bulk N (causing >15`N offsets to increase) or cyaobacterial contribution to export (causing >15`N offsets to decrease). Preliminary data show an average δ>15`N offset of ∼5-5.5ppm between bulk and chlorin N at all sites, suggesting predominantly algal export production irrespective of N<2` fixation regime and bulk values of δ>15`N. 
650 7 |a Biogenic processes  |2 georeft 
650 7 |a Cenozoic  |2 georeft 
650 7 |a Chlorophyll  |2 georeft 
650 7 |a Degradation  |2 georeft 
650 7 |a Diagenesis  |2 georeft 
650 7 |a Fixation  |2 georeft 
650 7 |a Holocene  |2 georeft 
650 7 |a Isotope ratios  |2 georeft 
650 7 |a Isotopes  |2 georeft 
650 7 |a N-15/N-14  |2 georeft 
650 7 |a Nitrogen  |2 georeft 
650 7 |a Ocean Drilling Program  |2 georeft 
650 7 |a Organic compounds  |2 georeft 
650 7 |a Pigments  |2 georeft 
650 7 |a Porphyrins  |2 georeft 
650 7 |a Quaternary  |2 georeft 
650 7 |a Stable isotopes  |2 georeft 
651 7 |a Atlantic Ocean  |2 georeft 
651 7 |a Bermuda Rise  |2 georeft 
651 7 |a East Pacific  |2 georeft 
651 7 |a Leg 172  |2 georeft 
651 7 |a Leg 202  |2 georeft 
651 7 |a Nazca Ridge  |2 georeft 
651 7 |a North Atlantic  |2 georeft 
651 7 |a ODP Site 1063  |2 georeft 
651 7 |a ODP Site 1234  |2 georeft 
651 7 |a ODP Site 1237  |2 georeft 
651 7 |a Pacific Ocean  |2 georeft 
651 7 |a South Pacific  |2 georeft 
651 7 |a Southeast Pacific  |2 georeft 
653 |a Cyanobacteria 
700 1 |a Robinson, Rebecca S., 
700 1 |a Pearson, Ann, 
711 2 |a Goldschmidt 2013  |d (2013 :  |c Florence, Italy)  
773 0 |t Goldschmidt abstracts 2013  |d London : Mineralogical Society, 2013  |k Mineralogical Magazine  |x 0026-461X  |y MNLMBB  |n Mineralogical Magazine, 77(5), p.1299; Goldschmidt 2013, Florence, Italy, Aug. 25-30, 2013. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0026-461X Publication type: conference paper or compendium article  |g Vol. 77, no. 5 
856 |u urn:doi: 10.1180/minmag.2013.077.5.8