{"NOAAStudyId":"23310","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","constraints":"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.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2018-01-14","dataPublisher":"NOAA","dataType":"PALEOLIMNOLOGY","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/lake","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-lake-23310.xml","doi":null,"earliestYearBP":1451,"earliestYearCE":499,"entryId":"noaa-lake-23310","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"P2C2 1358362"}],"investigators":"Stager, J.C.; Wiltse, B.; Hubeny, J.B.; Yankowsky, E.; Nardelli, D.; Primack, R.","mostRecentYearBP":-65,"mostRecentYearCE":2015,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/23310","originalSource":null,"publication":[{"abstract":"Recent shifts in the ecological condition of Walden Pond, MA, are of potentially wide interest due to the lake's importance as a cultural, historical, and recreational resource in addition to its scientific value as an indicator of local and global environmental change.  Algal microfossils in six sediment cores document changes in hydroclimate and trophic status of the lake during the last 1800 years and extend two previous sediment core records of shorter length.  Low percentages of planktonic diatoms in the longest cores (WAL-3, WAL-15) indicate shallowing and/or greater water clarity associated with a relatively arid interval during the Medieval Climate Anomaly, ca. A.D. 1150-1300. Cultural eutrophication of the lake since the A.D. 1920s caused diatoms in the genera Asterionella and Synedra to increase in relative abundance at the expense of Cyclotella, Discostella, and the chrysophyte alga Mallomonas allorgei.   Percentages of Asterionella and Synedra have remained fairly stable since A.D. 2000 when a previous sediment core study was conducted, but scaled chrysophytes have become more numerous. These findings suggest that, although mitigation efforts have curtailed anthropogenic nutrient inputs to Walden Pond, the lake has not returned to the pre-impact condition described by Henry David Thoreau and may become increasingly vulnerable to further changes in water quality in a warmer and possibly wetter future.","author":{"name":"Stager, J. Curt; Wiltse, Brendan; Hubeny, J. Bradford; Yankowsky, Eric; Nardelli, David; Primack, Richard"},"citation":"Stager, J. Curt; Wiltse, Brendan; Hubeny, J. Bradford; Yankowsky, Eric; Nardelli, David; Primack, Richard. 2018. Climate variability and cultural eutrophication at Walden Pond (Massachusetts, USA) during the last 1800 years. PLoS ONE. . ","edition":null,"identifier":null,"issue":null,"journal":"PLoS ONE","pages":null,"pubRank":"1","pubYear":2018,"reportNumber":null,"title":"Climate variability and cultural eutrophication at Walden Pond (Massachusetts, USA) during the last 1800 years","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"57582","geo":{"geoType":"Feature","geometry":{"coordinates":["42.439","-71.339"],"type":"POINT"},"properties":{"easternmostLongitude":"-71.339","maxElevationMeters":"47","minElevationMeters":"47","northernmostLatitude":"42.439","southernmostLatitude":"42.439","westernmostLongitude":"-71.339"}},"locationName":"Continent>North America>United States Of America>Massachusetts","mappable":"Y","paleoData":[{"NOAADataTableId":"34893","coreLengthMeters":0,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleolimnology>population abundance"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/massachusetts/walden2018diatom.txt","linkText":"Walden Pond Diatom Census Data","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"centimeter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"year Common Era","cvWhat":"age variable>age"},{"cvAdditionalInfo":"Cyclotella bodanica","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Discostella stelligera","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Synedra nanana","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Asterionella formosa","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Asterionella ralfsii","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Tabellaria flocculosa IIIP","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"total Eunotia","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Achnanthidium minutissimum","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Miscellaneous Pennales","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>identified diatom"},{"cvAdditionalInfo":"Ratio of chrysophyte scales to diatoms","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>organism index"},{"cvAdditionalInfo":"Ratio of chrysophyte cysts to diatoms","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>organism index"}]}],"dataTableName":"WAL-3diatom","dataTableNotes":"Piston core collected from the central basin of Walden Pond, MA","earliestYear":623,"earliestYearBP":1327,"earliestYearCE":623,"mostRecentYear":2015,"mostRecentYearBP":-65,"mostRecentYearCE":2015,"species":[],"timeUnit":"AD"},{"NOAADataTableId":"34894","coreLengthMeters":0,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleolimnology>population abundance"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/massachusetts/walden2018loi.txt","linkText":"Walden Pond Organic Matter and Planktonic Diatom Percentage","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"centimeter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"year Common Era","cvWhat":"age variable>age"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":"loss on ignition","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>bulk biological material>organic matter"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":"microscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"biological material>organism>diatom>diatom index>diatom habitat-based index>total planktic diatoms"}]}],"dataTableName":"WAL-3LOI","dataTableNotes":"Piston core collected from the central basin of Walden Pond, MA","earliestYear":499,"earliestYearBP":1451,"earliestYearCE":499,"mostRecentYear":2015,"mostRecentYearBP":-65,"mostRecentYearCE":2015,"species":[],"timeUnit":"AD"}],"siteName":"Walden Pond"}],"studyCode":null,"studyName":"Walden Pond, Massachusetts 1800 Year Diatom and Chrysophyte Data","studyNotes":"Diatom and chrysophyte records from Walden Pond core WAL-3, indicating hydroclimate and trophic changes during the last 1800 years.","version":"1.0","xmlId":"21494"}