TY - JOUR
T1 - Influence of open ocean nitrogen supply on the skeletal δ15N of modern shallow-water scleractinian corals
AU - Wang, Xingchen T.
AU - Sigman, Daniel Mikhail
AU - Cohen, Anne L.
AU - Sinclair, Daniel J.
AU - Sherrell, Robert M.
AU - Cobb, Kim M.
AU - Erler, Dirk V.
AU - Stolarski, Jarosław
AU - Kitahara, Marcelo V.
AU - Ren, Haojia
N1 - Funding Information:
This work was supported by the NSF Grants OCE-1060947 and OCE-1536368 to D.M.S. and OCE-1537338 to A.L.C., the MacArthur Foundation Fellows Program (D.M.S.), the Grand Challenges Program at Princeton University (D.M.S.), the Schlanger Fellowship Program of the Consortium for Ocean Leadership (X.T.W.), the Charlotte Elizabeth Procter Fellowship of the Graduate School at Princeton University (X.T.W.) and a Graduate Student Research Grant from the Geological Society of America (X.T.W.). We thank R. Fairbanks and R. Mortlock for supplying the Oman coral core. We thank P. Rafter, A. Alpert and B. Jonsson for helpful discussions and two anonymous reviewers for insightful comments.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - The isotopic composition of skeleton-bound organic nitrogen in shallow-water scleractinian corals (hereafter, CS-δ15N) is an emerging tool for studying the marine nitrogen cycle in the past. The CS-δ15N has been shown to reflect the δ15N of nitrogen (N) sources to corals, with most applications to date focusing on the anthropogenic/terrestrial N inputs to reef environments. However, many coral reefs receive their primary N sources from the open ocean, and the CS-δ15N of these corals may provide information on past changes in the open ocean regional and global N cycle. Using a recently developed persulfate/denitrifier-based method, we measured CS-δ15N in modern shallow-water scleractinian corals from 8 sites proximal to the open ocean. At sites with low open ocean surface nitrate concentrations typical of the subtropics and tropics, measured CS-δ15N variation on seasonal and annual timescales is most often less than 2‰. In contrast, a broad range in CS-δ15N (of ~10‰) is measured across these sites, with a strong correlation between CS-δ15N and the δ15N of the deep nitrate supply to the surface waters near the reefs. While CS-δ15N can be affected by other N sources as well and can vary in response to local reef conditions as well as coral/symbiont physiological changes, this survey indicates that, when considering corals proximal to the open ocean, the δ15N of the subsurface nitrate supply to surface waters drives most of the CS-δ15N variation across the global ocean. Thus, CS-δ15N is a promising proxy for reconstructing the open ocean N cycle in the past.
AB - The isotopic composition of skeleton-bound organic nitrogen in shallow-water scleractinian corals (hereafter, CS-δ15N) is an emerging tool for studying the marine nitrogen cycle in the past. The CS-δ15N has been shown to reflect the δ15N of nitrogen (N) sources to corals, with most applications to date focusing on the anthropogenic/terrestrial N inputs to reef environments. However, many coral reefs receive their primary N sources from the open ocean, and the CS-δ15N of these corals may provide information on past changes in the open ocean regional and global N cycle. Using a recently developed persulfate/denitrifier-based method, we measured CS-δ15N in modern shallow-water scleractinian corals from 8 sites proximal to the open ocean. At sites with low open ocean surface nitrate concentrations typical of the subtropics and tropics, measured CS-δ15N variation on seasonal and annual timescales is most often less than 2‰. In contrast, a broad range in CS-δ15N (of ~10‰) is measured across these sites, with a strong correlation between CS-δ15N and the δ15N of the deep nitrate supply to the surface waters near the reefs. While CS-δ15N can be affected by other N sources as well and can vary in response to local reef conditions as well as coral/symbiont physiological changes, this survey indicates that, when considering corals proximal to the open ocean, the δ15N of the subsurface nitrate supply to surface waters drives most of the CS-δ15N variation across the global ocean. Thus, CS-δ15N is a promising proxy for reconstructing the open ocean N cycle in the past.
KW - Coral
KW - Marine nitrogen cycle
KW - Nitrogen isotope
KW - Paleoceanography
UR - http://www.scopus.com/inward/record.url?scp=84959308825&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84959308825&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2016.02.032
DO - 10.1016/j.epsl.2016.02.032
M3 - Article
AN - SCOPUS:84959308825
SN - 0012-821X
VL - 441
SP - 125
EP - 132
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -