Abstract: The KN223 research cruise on board the R/V Knorr (Chief scientist Richard W. Murray; Principal investigators: Arthur J. Spivack, Steven D’Hondt, Robert A. Pockalny took place in October-December 2014 and had as primary goal to collect sedimentary pore water from a series of sites in the North Atlantic and determine if these samples can be used to (1) document how deep Atlantic meridional overturning circulation (AOM) of the last glacial maximum differed from that of the present, and (2) directly test the influence of last glacial maximum AMOC on atmospheric CO2 (via the pre-formed NO3- content of deep and intermediate water in the LGM North Atlantic). Measurement of dissolved oxygen at the studied sites are an important piece of information to meet these objectives. Oxygen measurements were performed at 9 sites across the North Atlantic, on 6 Multicores, 8 Gravity cores, and 9 Long Cores using an optical O2 sensor (PreSens MICROX TX3) . This dataset is presented here. Other Description: Steven D'Hondt, Fumio Inagaki, Carlos Alvarez Zarikian, Lewis J. Abrams, Nathalie Dubois, Tim Engelhardt, Helen Evans, Timothy Ferdelman, Britta Gribsholt, Robert N. Harris, Bryce W. Hoppie, Jung-Ho Hyun, Jens Kallmeyer, Jinwook Kim, Jill E. Lynch, Satoshi Mitsunobu, Yuki Morono, Richard W. Murray, Robert Pockalny, Justine Sauvage, Takaya Shimono, Fumito Shiraishi, David C. Smith, Christopher E. Smith-Duque, Arthur J. Spivack, Bjorn Olav Steinsbu, Yohey Suzuki, Michal Szpak, Laurent Toffin, Goichiro Uramoto, Yasuhiko T. Yamaguchi, Guo-liang Zhang, Xiao-Hua Zhang, Wiebke Ziebis, (2015), "Presence of oxygen and microbial communities from seafloor to basement in deep-sea sediment". Nature Geoscience