Bering Sea nitrate utilization and stratification since 1.2 Ma analyzed at IODP Site 323-U1342 Holes A, C, and D ...

• Main Authors: Knudson, Karla P, Ravelo, Ana Christina
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2017
• Subjects: Integrated Ocean Drilling Program / International Ocean Discovery Program IODP; Bering Sea; Subarctic
• Online Access: https://dx.doi.org/10.1594/pangaea.876202; https://doi.pangaea.de/10.1594/PANGAEA.876202

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 ... : 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 ...