noaa-lake-6198 Lake S41, Northwest Territories 2,000 Year Chironomid Inferred Temperature MacDonald, G.M.; Porinchu, D.F.; Rolland, N.; Kremenetskii, K.V.; Kaufman, D.S. Lake S41, Northwest Territories 2,000 Year Chironomid Inferred Temperature 2008-11-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/6198 Investigator G.M. MacDonald Investigator D.F. Porinchu Investigator N. Rolland Investigator K.V. Kremenetskii Investigator D.S. Kaufman earth science paleoclimate insect|paleolimnology total head capsules,sediment,null,count,null,insect|paleolimnology,null,null,N,null earth science paleoclimate paleolimnology volume,wet sediment,null,milliliter,null,paleolimnology,null,null,N,used to calculate head capsule acc. rate earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Chironomus anthracinus type earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Microtendipes sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Psectrocladius semicirculatus/sordidellus earth science paleoclimate climate reconstructions|insect|paleolimnology depth,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null earth science paleoclimate paleolimnology detrended correspondence analysis axis,null,null,dimensionless,null,paleolimnology,null,null,N,axis 1 earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Stichtochironomus sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Micropsectra sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Corynocera ambigua earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Heterotrissocladius sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Limnophyes sp. earth science paleoclimate paleolimnology detrended correspondence analysis axis,null,null,dimensionless,null,paleolimnology,null,null,N,axis 2 earth science paleoclimate paleolimnology sedimentation rate,sediment,null,centimeter per year,null,paleolimnology,null,null,N,used to calculate head capsule acc. rate earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,cf. bathophila-Parakiefferiella sp.B earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Pseudosmittia sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Pentaneurini earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Procladius sp. earth science paleoclimate climate reconstructions|insect|paleolimnology surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,null earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Sergentia sp. earth science paleoclimate climate reconstructions|insect|paleolimnology lake surface temperature,midge assemblage,null,degree Celsius,summer,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 insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Polypedilum sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Corynocera oliveri earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Corynoneura sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Paracladius sp. earth science paleoclimate insect|paleolimnology total head capsules,sediment,null,count per square centimeter per year,null,insect|paleolimnology,null,null,N,Head capsule accumulation rate earth science paleoclimate paleolimnology detrended correspondence analysis axis,null,null,dimensionless,null,paleolimnology,null,null,N,axis 3 earth science paleoclimate paleolimnology biogenic silica,sediment,null,milligram per gram,null,paleolimnology,null,null,N,null earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Dicrotendipes sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanytarsus sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanytarsus lugens type earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Cricotopus sp. earth science paleoclimate paleolimnology organic matter,sediment,null,percent,null,paleolimnology,null,loss on ignition,N,null earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Cladopelma sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Cladotanytarsus mancus earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Paratanytarsus sp. earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Zalutschia species A earth science paleoclimate insect|paleolimnology identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Psectrocladius septentrionalis earth science paleoclimate paleolimnology population abundance geoscientificInformation Air Temperature Reconstruction PAGES 2k Network PAGES Arctic 2k 1930 cal yr BP -50 cal yr BP Complete 63.718 63.718 -109.318 -109.318 Continent North America Canada Northwest Territories Lake S41>LATITUDE 63.718>LONGITUDE -109.318 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII MacDonald, G.M., D.F. Porinchu, N. Rolland, K.V. Kremenetsky, and D.S. Kaufman 2009 Journal of Paleolimnology 41 1 129-141 10.1007/s10933-008-9250-2

Instrumental climate records from the central Canadian treeline zone display a pattern of variation similar to general Northern Hemisphere temperature trends. To examine whether this general correspondence extends back beyond the instrumental record, we obtained a sediment core from Lake S41, a small lake in the Northwest Territories of Canada at 63deg 43.11'N, 109 deg 19.07'W. A radiocarbon-based chronology was developed for the core. The sediments were analyzed for organic-matter content by loss-on-ignition (LOI), biogenic-silica content (BSi), and chironomid community composition to reconstruct July air temperature and summer water temperature. The paleolimnological records were compared with records of atmospheric CO2 concentration, solar variability, and hemispheric temperature variations over the past 2000 years. The results of the analyses suggest that widely-documented long-term variations in Northern Hemisphere temperature associated with radiative forcing, namely the cooling following the medieval period during the Little Ice Age (LIA), and twentieth century warming, are represented in the central Canadian treeline zone. There is also evidence of a brief episode of warming during the eighteenth century. As evidenced by LOI and BSi, the twentieth century warming is typified by increased lake productivity relative to the LIA. Depending upon the measure, the increased productivity of the twentieth century nearly equals or exceeds that of any other period in the past 2000 years. In contrast, the rate of chironomid head capsule accumulation decreased and remained low during the twentieth century. Although the chironomid-inferred temperature reconstructions indicate cooling during the LIA, they present no evidence of greatly increased temperatures during the twentieth century. Warming during the twentieth century might have enhanced lake stratification, and the response of the chironomid fauna to warming was attenuated by decreased oxygen and lower temperatures in the hypolimnion of the more stratification-prone lake. STUDY NOTES: Chironomid-inferred summer air and surface water temperature, plus LOI and BSi data for Lake S41, Northwest Territories, Canada.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/nwt/s41-2008.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/nwt/s41-2008.txt USA/NOAA DIF Version 9.8.4 2019-03-27 2019-03-27