Bering Sea nitrate utilization and stratification since 1.2 Ma analyzed at IODP Site 323-U1342 Holes A, C, and D, supplement to: Knudson, Karla P; Ravelo, Ana Christina (2015): Enhanced subarctic Pacific stratification and nutrient utilization during glacials over the last 1.2 Myr. Geophysical Research Letters, 42(22), 9870-9879


The relationship between climate, biological productivity, and nutrient flux is of considerable interest in the subarctic Pacific, which represents an important high-nitrate, low-chlorophyll region. While previous studies suggest that changes in iron supply and/or physical ocean stratification could hypothetically explain orbital-scale fluctuations in subarctic Pacific nutrient utilization and productivity, previous records of nutrient utilization are too short to evaluate these relationships over many glacial-interglacial cycles. We present new, high-resolution records of sedimentary d15N, which offer the first opportunity to evaluate systematic, orbital-scale variations in subarctic Pacific nitrate utilization from 1.2 Ma. Nitrate utilization was enhanced during all glacials, varied with orbital-scale periodicity since the mid-Pleistocene transition, was strongly correlated with enhanced aeolian dust and low atmospheric CO2, but was not correlated with productivity. These results suggest that glacial stratification, rather than iron fertilization, systematically exerted an important regional control on nutrient utilization and air-sea carbon flux.

Metadata Access
Creator Ravelo, Ana Christina;Knudson, Karla P
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported (CC-BY)
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Discipline Earth System Research
Spatial Coverage (55N-58N,177E-176W)