Global Ocean Glacial Export Production Data Kohfeld, K.E.; Le Quéré, C.; Harrison, S.P.; Anderson, R.F. Kohfeld, K.E. Le Quéré, C. Harrison, S.P. Anderson, R.F. biogeochemical cycles earth science/paleoclimate/paleocean (Global>LATITUDE >LONGITUDE ) It has been hypothesized that changes in the marine biological pump caused a major portion of the glacial reduction of atmospheric carbon dioxide by 80 to 100 parts per million through increased iron fertilization of marine plankton, increased ocean nutrient content or utilization, or shifts in dominant plankton types. We analyze sedimentary records of marine productivity at the peak and the middle of the last glacial cycle and show that neither changes in nutrient utilization in the Southern Ocean nor shifts in plankton dominance explain the CO2 drawdown. Iron fertilization and associated mechanisms can be responsible for no more than half the observed drawdown. STUDY NOTES: Tables and Table Notes Table S1. Change in export production at the LGM relative to Late Holocene. Table S2. Change in export production at the LGM relative to Stage 5a-d. Table S3. Change in export production at Stage 5a-d relative to Late Holocene. Table Notes Dating Control: d18O = oxygen isotope stratigraphy; 14C = radiocarbon dating of single species of foraminifera; LC = lithogenic correlation. CFP = Constant Flux Proxy. “Y” indicates that accumulation rates were corrected for sediment focusing using 230Th normalization. Data Evaluation: Data for each core were given scores for each of the three categories: (a) the quality of sediment age models, (b) the means by which sediment flux measurements are determined, and (c) the number and agreement between the indicators within a core. The four different types of age models were scored as follows: AMS radiocarbon dating = 4; marine isotope stratigraphy = 3; bulk radiocarbon or 230Th methods = 2; and lithogenic correlation = 1. Sediment flux measurements that used a ‘constant flux proxy’ such as 230Th normalization were given the highest score of 4. Sediment sites with mass accumulation rates that did not use 230Th normalization received a score of 2. Sites where only concentrations were determined received a score of 1. Finally, number of proxies measured in each core multiplied by the fraction of agreement between these proxies determined the third score. The final score (the sum of the score for the three categories) determined whether the data from that core received a confidence ranking of “high” (scores 10-14), “intermediate” (scores 7-10), or “low” (scores 6 or below). Assessed Change in Productivity and Productivity Indicators: Changes represent conditions at the LGM relative to today: -1 = decrease; -0.5 = slight decrease; 0 = no change; +0.5 = slight increase; 1 = increase; 99 = no assessment possible. All changes are based on accumulation rates unless otherwise indicated (in comments, or as a code of “1” in the “flux code” column). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Kohfeld, K.E. Investigator : Le Quéré, C. Investigator : Harrison, S.P. Investigator : Anderson, R.F. 2012-01-27 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12423 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.txt English https://www.ncdc.noaa.gov/paleo/study/12423 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kohfeld2005/kohfeld2005.txt Kohfeld, K.E., C. Le Quéré, S.P. Harrison, and R.F. Anderson. 2005. Role of Marine Biology in Glacial-Interglacial CO2 Cycles. Science, Vol. 308, No. 5718, pp. 74-78, 1 April 2005. DOI: 10.1126/science.1105375 START YEAR: 100000 cal yr BP * END YEAR: 18000 cal yr BP -180 -90 180 90