Foraminiferal isotope evidence of reduced nitrogen fixation in the Ice Age Atlantic ocean

Fixed nitrogen ( N) is a limiting nutrient for algae in the low- latitude ocean, and its oceanic inventory may have been higher during ice ages, thus helping to lower atmospheric CO2 during those intervals. In organic matter within planktonic foraminifera shells in Caribbean Sea sediments, we found...

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Bibliographic Details
Published in:Science
Main Authors: Ren, Haojia, Sigman, Daniel M., Meckler, Anna Nele, Plessen, Birgit, Robinson, Rebecca S., Rosenthal, Yair, Haug, Gerald H.
Format: Article in Journal/Newspaper
Language:English
Published: 2009
Subjects:
Institut für Geowissenschaften
Planktonic foraminifera
Online Access:https://publishup.uni-potsdam.de/opus4-ubp/frontdoor/index/index/docId/31874
https://doi.org/10.1126/science.1165787
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Summary:Fixed nitrogen ( N) is a limiting nutrient for algae in the low- latitude ocean, and its oceanic inventory may have been higher during ice ages, thus helping to lower atmospheric CO2 during those intervals. In organic matter within planktonic foraminifera shells in Caribbean Sea sediments, we found that the N-15/N-14 ratio from the last ice age is higher than that from the current interglacial, indicating a higher nitrate N-15/N-14 ratio in the Caribbean thermocline. This change and other species- specific differences are best explained by less N fixation in the Atlantic during the last ice age. The fixation decrease was most likely a response to a known ice age reduction in ocean N loss, and it would have worked to balance the ocean N budget and to curb ice age- interglacial change in the N inventory.

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