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Harvard Forest Data Archive

HF028

Paleolimnology of Lakes in Central New England from 2000 BP to Present

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Data

Overview

  • Lead: Donna Francis, David Foster
  • Investigators:
  • Contact: David Foster
  • Start date: 0001
  • End date: 2000
  • Status: completed
  • Location: Central New England
  • Latitude: +42.55 to +42.85
  • Longitude: -72.45 to -71.97
  • Elevation:
  • Taxa: Chironomidae
  • Release date: 2003
  • Revisions:
  • EML file: knb-lter-hfr.28.17
  • DOI: digital object identifier
  • Related links:
  • Study type: paleological
  • Research topic: historical and retrospective studies; regional studies
  • LTER core area: disturbance
  • Keywords: forest disturbance, human disturbance, land use, paleolimnology
  • Abstract:

    Paleolimnological studies of three small watersheds in central New England were undertaken to determine the influence of deforestation and agriculture on lake systems, as well as the response of the lakes to agricultural abandonment and reforestation, or the cessation of disturbance. Sites were chosen to represent a range of past land-use activities, while keeping other site factors constant. The study was designed to complement the historical and paleoecological studies of the central Massachusetts area of Fuller et al. (1998) and Foster et al. (1998). Changes in terrestrial vegetation were documented using the pollen record from each lake, and changes in aquatic systems were documented through fossil chironomid assemblages (Chironomidae: Diptera) and sediment chemistry. Dated cores were analyzed for pollen, fossil chironomids, percent organic matter, carbon and nitrogen, and sedimentation changes. Increased sedimentation rates occurred in all lakes during the settlement period, and small increases in productivity changes resulted from the increased runoff. Productivity changes, as indicated by organic material, C:N ratios, and chironomid assemblages, are more pronounced in North Round and Wickett Ponds than in Pecker Pond, even though agricultural activity was most intense at Pecker Pond. North Round and Wickett Ponds are more shallow than Pecker, and were more affected by sediment and nutrient inputs from the watershed. North Round Pond was the least impacted site, with only minimal logging and no agriculture, but still significant changes occurred during the settlement period. The sedimentation rates and productivity continue to be higher than pre-settlement levels, indicating that the systems have not returned to pre-disturbance states. This is similar to the response of forest vegetation studied by Fuller et al. (1998) in the Central Massachusetts study. The low intensity agricultural practices of the 19th Century and small watershed sizes contributed to the fact that the response of these lakes was minimal.

  • Methods:

    Sediment analyses

    % organic carbon was determined by standard loss-on-ignition at 550°C {Dean 1974 #1320}. Total carbon and nitrogen were determined for 5-6 mg dry subsamples wit a Fisons 1500 n/C CHN Analyzer. Average recovery of a known standard (atropine) was 99% for both nitrogen and carbon. Particle size was analyzed on 1 g subsamples previously treated with 30% h2O2 to remove organic material. Analysis was done with a Coulter LS 200 laser-diffraction particle-size analyzer employing fluid module software and a Fraunhofer optical model.

    Pollen analysis

    Sediment preparation for pollen analysis followed standard procedures . At least 500 arboreal pollen grains were counted for each level. Pollen percentages were based on a pollen sum of all terrestrial pollen grains and spores. The timing of European settlement in the cores was assessed from changes in pollen representing open vegetation, including a decline in tree pollen and an increase in herbaceous pollen, especially ragweed (Ambrosia), sorrel (Rumex) and grass (Poaceae).

    210Pb dating

    Activity of 210Pb in sediment samples was determined by the alpha activity of its daughter product 210Po after samples were prepared using the method D.R. Engstrom (personal communication). 210Pb inventory was counted on an Ortec Alpha Spectrometer 576A. Ages and sediment accumulation rates were calculated with a CRS (constant rate of supply) point transformation model {Binford 1990 #1350}{Binford, Kahl, et al. 1993 #1340}.

    Radiocarbon dating

    Bulk sediment samples (4-5 g) were analyzed at Beta Analytic, Miami, Florida, for 14C dates. The resulting determinations were converted to calendar years with the program Calib version 3.0 based on a combination of marine coral and bidecadal tree-ring data sets {Stuiver and Reimer 1993 #1410}. Age models were derived from radiocarbon dates of lake sediments along with 210Pb dates for each site. Linear interpolations were made between 14C dates. An age of 250 years was chosen for the settlement horizons based on historical information.

    Charcoal analysis

    Microscopic charcoal was tallied for each core by the point-intercept method. Eucalyptus pollen suspension of known volume and concentration was added to each sample during preparation, and eucalyptus pollen grains were counted simultaneously with charcoal to estimate charcoal-pollen ratios.

  • Use:

    This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.

  • Citation:

    Francis D, Foster D. 2003. Paleolimnology of Lakes in Central New England from 2000 BP to Present. Harvard Forest Data Archive: HF028.

Detailed Metadata

hf028-01: sediment chemistry

  1. pond: pond name
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  2. depth: depth of sample in the sediment column (unit: centimeter / missing value: NA)
  3. psize: percent sand as determined by laser particle size analysis (unit: dimensionless / missing value: NA)
  4. org.per: percent organic carbon as determined by loss-on-ignition method (unit: dimensionless / missing value: NA)
  5. c.per: percent inorganic carbon as determined by loss-on-ignition method (unit: dimensionless / missing value: NA)
  6. total.c.per: percent total carbon as determined on a Carbon –Nitrogen (CN) analyzer (unit: dimensionless / missing value: NA)
  7. n.per: percent total carbon as determined on a CN analyzer (unit: dimensionless / missing value: NA)
  8. c.n: ratio of percent total carbon to percent total nitrogen (unit: number / missing value: NA)

hf028-02: pollen

  1. pond: pond name
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  2. depth: depth of sample in the sediment column (unit: centimeter / missing value: NA)
  3. taxa: individual taxa. Indet. Crumple: indeterminable crumpled pollen grains. Indet. Corroded: indeterminable corroded pollen grains. Indet. Obscured: indeterminable obscured pollen grains. Unknown: unknown or unidentified pollen grains. Exotic: exotic pollen grains.
  4. count: number of pollen grains of individual taxa identified (unit: number / missing value: NA)

hf028-03: Pb210 dates

  1. pond: pond name
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  2. depth: depth of sample in the sediment column (unit: number / missing value: NA)
  3. age: age in years before sediment core was taken (unit: number / missing value: NA)
  4. analysis: analysis by which age was determined
    • Pb210: lead 210 analysis interpreted by constant rate of supply method
    • Pollen: rise in Ambrosia and agricultural weeds associated with European settlement

hf028-04: C14 dates

  1. pond: pond name
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  2. depth: depth of sample in centimeters in the sediment column
  3. age: age in years before present (years before 1950) (unit: number / missing value: NA)
  4. analysis: analysis by which age was determined. AMS = Accelerated mass. Spectrometry radiocarbon analysis on lacustrine organic matter.
  5. error: error in radiocarbon date reported by lab (± years) (unit: number / missing value: NA)
  6. cal.ybp: calibrated radiocarbon date, in years before 1950, determined by Calib 4 (unit: number / missing value: NA)

hf028-05: water chemistry

  1. date: date measurement was taken
  2. month: month measurement was taken
  3. day: day measurement was taken
  4. year: year measurement was taken
  5. pond: pond measurement was taken from
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  6. depth: depth at which measurement was taken (unit: meter / missing value: NA)
  7. temp: temperature °C (unit: celsius / missing value: NA)
  8. conductivity: conductivity in micro mhos (unit: number / missing value: NA)
  9. tss: total suspended solids in mg/L (unit: milligramsPerLiter / missing value: NA)
  10. ph: pH (unit: number / missing value: NA)
  11. chl.a: chlorophyll a concentration in µ g/L (unit: microgramsPerLiter / missing value: NA)
  12. phaeo: Phaeopigment concentration in µ g/L (unit: microgramsPerLiter / missing value: NA)
  13. alkalinity: alkalinity in meq/L (unit: number / missing value: NA)
  14. do: dissolved oxygen in mg/L (unit: milligramsPerLiter / missing value: NA)

hf028-06: chironomids

  1. pond: pond name
    • Pecker: Pecker Pond
    • Wickett: Wickett Pond
  2. depth: depth of sample in centimeters in the sediment column
  3. taxa: chironomid taxa
  4. count: chironomid taxa counts (unit: number / missing value: NA)

hf028-07: grain size

  1. pond: pond name
    • Wickett: Wickett Pond
  2. class.name: class of sediment particle
  3. phi.size: size of particle in Phi measurement
  4. particle.diam: size of particle in µm
  5. depth: depth of sample in cm
  6. vol.per: percent of the sample, by volume, of each particle size class. Blanks= sample lost. (unit: dimensionless / missing value: NA)