Ongoke Lake, Alaska 2,000 Year Diatom, Chironomid, and Geochemical Data Chipman, M.L.; Clarke, G.H.; Clegg, B.F.; Gregory-Eaves, I.; Hu, F.S. Chipman, M.L. Clarke, G.H. Clegg, B.F. Gregory-Eaves, I. Hu, F.S. 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diatom,null,null,percent,null,paleolimnology,null,null,N,Aulacoseira nygaardii) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Aulacoseira subarctica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Aulacoseira tenella) earth science/paleoclimate/paleolimnology (organic matter,sediment,null,weight percent,null,paleolimnology,null,loss on ignition,N,loss on ignition 550 degrees C for four hours) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Sergentia sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes bioseleltiana) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes carrisima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes helvetica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes impexiformis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella stelligera c.f. stelligera) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella amphicephala) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella cistula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella paucistriata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diatoma tenue) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diploneis ovalis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Eunotia acus) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria brevistriata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria capucina var. perminuta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria construens) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria construens var. mesolepta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria robusta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Gomphonema sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Melosira varians) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula bremensis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula capitata var. hungarica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula clementiodes) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula laevissima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula radiosa var. parva) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula subatomoides) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula subtillisima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula tuscula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia frustulum) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia inconspicua) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia paleacea) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia perminuta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia pura) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia pusilla) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia brandeli) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia major) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Rhopalodia gibba) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Stauroneis anceps) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Stauroneis phoenicenteron) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Synedra sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Synedra/Fragilaria parasitica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Synedra/Fragilaria rumpens) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Synedra rumpens va. scotica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria pseudoconstruens) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Aulacoseira crassipunctata) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth at sample end,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (biogenic silica,sediment,null,milligram per gram,null,paleolimnology,null,spectrophotometry,N,method of Mortlock and Froelich 1989 with 10% Na2CO3) earth science/paleoclimate/paleolimnology (planktic:benthic diatom,null,null,dimensionless,null,paleolimnology,null,null,N,ratio of # of planktonic and tychoplanktonic diatoms to # of benthic diatoms) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes curtissima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cocconeis placentula var. euglypta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella bodanica var. aff. lemanica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella pseudostelligera) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella tripartita) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella gracilis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella silesiaca) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diatoma mesodon) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diploneis sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Eunotia faba) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria construens var. venter) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria exigua) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria parasitica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria virescens) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Gomphonema truncatum) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula mediocris) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula medioconvexa) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula submuralis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula trivialis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Naviculadicta sp. 1) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia dissipata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia gibba var. linearis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Reimeria sinuata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria capucina var. gracilis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia viridis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes peragalli) earth science/paleoclimate/climate reconstructions|paleolimnology (lake level,diatom assemblage,unspecified margin of error,meter,null,climate reconstructions|paleolimnology,null,null,N,water depth of lake) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Asterionella formosa) earth science/paleoclimate/paleolimnology (total diatoms,null,null,count per gram,null,paleolimnology,null,null,N,Diatom concentration expressed as 10^8 diatom frustules/g of dry sediment) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes altaica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes calcar) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes didyma) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella kuetzingiana var. radiosa/C. rossi) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diploneis finnica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Epithemia adnata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Eunotia flexuosa) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria capucina var. amphicephala) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula atomus) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula explanata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula globulifera) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula minuscula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula modica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula pseudocutiformis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula pupula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Nitzschia angustata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia interrupta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia microstauron) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia subcapitata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Surirella sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Synedra/Fragilaria tenera) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Tabellaria flocculosa) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes minuscula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes minutissima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes nitidiformis) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth at sample start,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes exigua) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes kreigeri) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Achnanthes lacus-vulcani) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Caloneis sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Caloneis silicula) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella stelligera) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cyclotella stelligeroides) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbella incerta) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Cymbells perpusilla) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Diploneis elliptica) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Eunotia sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria sp.) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Fragilaria construens var. binolis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Gomphonema acuminatum) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Gomphonema parvulum) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Meridion circulare) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula agrestis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula augustata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula arvensis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula capitata) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula clementis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula dententa) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula minima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula pusio) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula rhynchocephala) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula ventralis) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Navicula vitiosa) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Neidium bisulcatum) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Neidium dubium) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Neidium septentrionale) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Pinnularia divergentissima) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Stauroneis smithii) earth science/paleoclimate/paleolimnology (identified diatom,null,null,percent,null,paleolimnology,null,null,N,Stenopterobia curvula) earth science/paleoclimate/paleolimnology (Ongoke Lake>LATITUDE 59.25>LONGITUDE -159.416) We analyzed sediments of the past 2000 years from Ongoke Lake, southwest Alaska, for organic carbon, organic nitrogen, biogenic silica (BSi), and diatom assemblages at decadal to centennial resolution to infer limnological changes that may be related to climatic variation in southwestern Alaska. The chronology is based on a 210Pb profile from bulk sediments and nine AMS 14C ages from terrestrial plant macrofossils. Four of the 14C ages span a core depth interval of 60.5 cm but are statistically indistinguishable from one another with a mean of ~1300 AD, which compromises the determination of temporal trends at Ongoke Lake and comparison with other paleoclimate records. The diatom record suggests changes in the duration of ice cover and strength of thermal stratification that are probably related to temperature variation. This variation includes a cold interval around the first millennium cooling (FMC) and a warm interval spanning the medieval climate anomaly (MCA). However, the lake-sediment record shows no clear signals of temperature variation for the period of the Little Ice Age (LIA) or the twentieth century. Climatic changes during these periods may have been manifested through effective-moisture (precipitation minus evapotranspiration) variation in the Ongoke Lake area. We estimate water depths and infer effective-moisture fluctuations by applying a regional transfer function to our diatom record. Together with inferences from diatom autecologies, this water-depth reconstruction suggests that effective moisture increased steadily from 50 BC to 350 AD, which was followed by relatively dry conditions between 550 and 750 AD and relatively wet conditions between 750 and 1450 AD. Effective moisture was low from ~1450 to 1850 AD, coinciding with the LIA; an alternative age model places this interval between ~1315 and 1850 AD. During the past 150 years, effective moisture increased, with estimated water depths reaching peak values in the second half of the twentieth century. This study offers the first paleolimnological record for inferring centennial-scale climatic variation over the past two millennia from southwestern Alaska. STUDY NOTES: High resolution diatom and chironomid counts and geochemical data (bulk density, LOI, lithics, C/N, biogenic Si) for Ongoke Lake, Alaska, for the past 2000 years. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Chipman, M.L. Investigator : Clarke, G.H. Investigator : Clegg, B.F. Investigator : Gregory-Eaves, I. Investigator : Hu, F.S. 2008-11-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/6194 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.txt English https://www.ncdc.noaa.gov/paleo/study/6194 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/ongoke2008.txt Chipman, M.L., G.H. Clarke, B.F. Clegg, I. Gregory-Eaves, and F.S. Hu2009A 2000 year record of climatic change at Ongoke Lake, southwest AlaskaJournal of Paleolimnology41157-750.1007/s10933-008-9257-8 START YEAR: 1998 cal yr BP * END YEAR: -54 cal yr BP -159.416 59.25 -159.416 59.25