Cariaco Basin, 35-55 ka Bulk Sediment and Foraminiferal Geochemistry Gibson, K.A.; Thunell, R.C.; Tappa, E.J.; Peterson, L.C.; McConnell, M. Gibson, K.A. Thunell, R.C. Tappa, E.J. Peterson, L.C. McConnell, M. earth science/paleoclimate/climate reconstructions|paleoceanography (sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,using G. ruber) earth science/paleoclimate/paleoceanography (nitrogen,sediment,null,weight percent,null,paleoceanography,null,elemental analysis,N,null) earth science/paleoclimate/paleoceanography (delta 15N,sediment,null,per mil,null,paleoceanography,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (magnesium/calcium,Globigerinoides ruber,null,millimole per mole,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (organic carbon,sediment,null,weight percent,null,paleoceanography,null,elemental analysis,N,null) earth science/paleoclimate/paleoceanography (iron,sediment,null,weight percent,null,paleoceanography,null,energy-dispersive x-ray fluorescence spectroscopy,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (molybdenum,sediment,null,weight percent,null,paleoceanography,null,energy-dispersive x-ray fluorescence spectroscopy,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (MD03-2621>LATITUDE 10.67817>LONGITUDE -64.9715) Understanding changes to the marine nitrogen cycle on millennial and shorter time scales can help determine the influence of rapid climate change on the fixed N pool and its sources and sinks. Rapid changes in denitrification have been observed in the eastern tropical North Pacific (ETNP) and Arabian Sea; however, millennial scale d15N records in regions influenced by N2 fixation are sparse. We present a sedimentary d15N record from the Cariaco Basin during marine isotope stage (MIS) 3 (~35-55 ka). The d15N record displays a pattern of millennial scale variability that tracks the Greenland ice core Dansgaard-Oeschger cycles, with higher values observed during interstadial periods, lower values during stadial periods, and abrupt transitions in between. Conditions during interstadials are similar to those at present in the Cariaco Basin, with the sedimentary d15N signal reflecting a combination of local processes and an imported regional signal. If interpreted to reflect regional processes, the interstadial d15N values (average ~5.1 per mil) support the argument that N2 fixation did not increase in the tropical North Atlantic during the last glacial. The lower d15N values during stadials, when lower sea level resulted in increased physical isolation of the basin, can be explained primarily by local processes. In spite of the importance of local processes, striking similarity is observed between the Cariaco record and millennial scale d15N records from the ETNP and Arabian Sea. The apparent synchronicity of changes observed in all three regions suggests an atmospheric teleconnection between the three sites and high-latitude climate forcing during MIS 3. STUDY NOTES: This data set contains bulk sediment (%TOC, %N, d15N, scanning XRF) and foraminferal geochemistry (Mg/Ca) used to reconstruct millennial-scale nutrient cycle dynamics in the Cariaco Basin during MIS 3. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Gibson, K.A. Investigator : Thunell, R.C. Investigator : Tappa, E.J. Investigator : Peterson, L.C. Investigator : McConnell, M. 2015-06-18 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/18897 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mo-fe.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015d15n-toc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mg-ca-sst.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mo-fe.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015d15n-toc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mg-ca-sst.txt English https://www.ncdc.noaa.gov/paleo/study/18897 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mo-fe.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015d15n-toc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gibson2015/gibson2015mg-ca-sst.txt Kelly Ann Gibson, Robert C. Thunell, Eric J. Tappa, Larry C. Peterson, Martha McConnell2015The influence of rapid, millennial scale climate change on nitrogen isotope dynamics of the Cariaco Basin during marine isotope stage 3Paleoceanography303253-26810.1002/2014PA002684http://onlinelibrary.wiley.com/doi/10.1002/2014PA002684/full START YEAR: 55004 cal yr BP * END YEAR: 35001 cal yr BP -64.9715 10.67817 -64.9715 10.67817