200KYr Midge Temperature, Diatom pH, and C/N Data Axford, Y.; Briner, J.P.; Cooke, C.A; Francis, D.R.; Michelutti, N.; Miller, G.H.; Smol, J.P.; Thomas, E.K.; Wilson, C.R.; Wolfe, A.P. Axford, Y. Briner, J.P. Cooke, C.A Francis, D.R. Michelutti, N. Miller, G.H. Smol, J.P. Thomas, E.K. Wilson, C.R. Wolfe, A.P. Air Temperature Reconstruction Arctic earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Eunotia exigua) earth science/paleoclimate/paleolimnology (carbon,sediment,null,weight percent,null,paleolimnology,null,elemental analysis,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Eastern Canada Francis et al. 2006 and Eastern Canada Walker et al. 1997; weighted-averaging regression) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (lake surface temperature,midge assemblage,null,degree Celsius,summer,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Eastern Canada Francis et al. 2006 and Eastern Canada Walker et al. 1997; weighted averaging regression with tolerance downweighting) earth science/paleoclimate/paleolimnology (chlorophyll,null,null,milligram per gram,null,paleolimnology,null,null,N,chlorophyll a) earth science/paleoclimate/paleolimnology (mass,dry sediment,null,gram per square centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,optima < 10 degrees Celsius) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,optima 10-15 deg C) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Aulacoseira sp.) earth science/paleoclimate/climate reconstructions|paleolimnology (pH,diatom assemblage|lake water,null,dimensionless,null,climate reconstructions|paleolimnology,null,regression analysis,N,calibration data set: Baffin Island Joynt and Wolfe 2001; weighted-averaging regression) earth science/paleoclimate/insect|paleolimnology (sample identification,null,null,null,null,insect|paleolimnology,null,null,C,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,year Common Era,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,null,elemental analysis,N,bulk sediment C/N) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,optima >15 deg C) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria sp.) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Lake CF8>LATITUDE 70.55>LONGITUDE -68.95) The Arctic is currently undergoing dramatic environmental transformations, but it remains largely unknown how these changes compare with long-term natural variability. Here we present a lake sediment sequence from the Canadian Arctic that records warm periods of the past 200,000 years, including the 20th century. This record provides a perspective on recent changes in the Arctic and predates by approximately 80,000 years the oldest stratigraphically intact ice core recovered from the Greenland Ice Sheet. The early Holocene and the warmest part of the Last Interglacial (Marine Isotope Stage or MIS 5e) were the only periods of the past 200,000 years with summer temperatures comparable to or exceeding today's at this site. Paleoecological and geochemical data indicate that the past three interglacial periods were characterized by similar trajectories in temperature, lake biology, and lakewater pH, all of which tracked orbitally-driven solar insolation. In recent decades, however, the study site has deviated from this recurring natural pattern and has entered an environmental regime that is unique within the past 200 millennia. STUDY NOTES: Multiproxy sediment data from Lake CF8, Baffin Island, Nunavut, Canada for the last 200,000 years. Included are fossil midge data and inferred water and air temperatures, diatom data and diatom-inferred pH, Gyttja dry mass, Chlorophyll-a, C/N ratio, and Carbon content data. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Axford, Y. Investigator : Briner, J.P. Investigator : Cooke, C.A Investigator : Francis, D.R. Investigator : Michelutti, N. Investigator : Miller, G.H. Investigator : Smol, J.P. Investigator : Thomas, E.K. Investigator : Wilson, C.R. Investigator : Wolfe, A.P. 2010-11-17 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/9896 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.txt English https://www.ncdc.noaa.gov/paleo/study/9896 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/baffin/cf8-2009.txt Axford, Y., J.P. Briner, C.A. Cooke, D.R. Francis, N. Michelutti, G.H. Miller, J.P. Smol, E.K. Thomas, C.R. Wilson, and A.P. Wolfe. 2009. Recent changes in a remote Arctic lake are unique within the past 200,000 years. Proceedings of the National Academy of Sciences, Vol. 106, pp. 18443-18446. START YEAR: 200000 cal yr BP * END YEAR: 907 cal yr BP -68.95 70.55 -68.95 70.55