Late Holocene Pollen Stratigraphy in Four Northeastern United States Lakes

Gajewski, Konrad; Swain, Albert M.; Peterson, George M.

doi:10.7202/032693ar

Cited by 17 publications

(13 citation statements)

References 34 publications

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“…The two oldest time periods ( ad 1200–1350 and ad 1500–1600) correspond to a high frequency of fire events with a low flux of deposition compared with the ad 1830–1930 time period, which was characterized by less frequent events of high intensity (Savarino and Legrand, 1998). The authors found that their Index of Fire is in fairly good agreement with charcoal records obtained from three sites in Maine (Conroy Lake and Basin Pond) and New York (Clear Pond) by Gajewski (1985), suggesting that Eastern North America is the source of biomass burning material in central Greenland over the last millennium.…”

Section: Ice-core Records Of Changes In Biomass Burningsupporting

confidence: 57%

Ice-core records of biomass burning

Rubino

D’Onofrio

Seki

et al. 2015

The Anthropocene Review

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We review the approaches for estimating biomass burning from ice-cores and consider the challenges and assumptions in their application. In particular, we consider the potential of biomarker proxies for biomass burning, hitherto not widely applied to glacial ice archives. We also review the available records of biomass burning in ice-cores and consider how variations in fire regimes have been related to atmospheric and land-use changes. Finally, we suggest that future developments in ice-core science should aim to combine multiple biomarkers with other records (black carbon, charcoal) and models to discern the types of material being burnt (C 3 versus C 4 plants, angiosperms, gymnosperms, peat fires, etc.) and to improve constraints on source areas of biomass burning. An ultimate goal is to compare the biomass burning record from ice-cores with hindcasts from models to project how future climate change will influence biomass burning and, inversely, how fire will affect climate.

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Section: Ice-core Records Of Changes In Biomass Burningsupporting

confidence: 57%

Ice-core records of biomass burning

Rubino

D’Onofrio

Seki

et al. 2015

The Anthropocene Review

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“…Our climatic interpretation of the Wolf-62 diatom series broadly corroborates the Clear Pond pollen record (Gajewski et al, 1987) in that both indicate exceptionally dry conditions in the Adirondacks c. AD 500-1000 followed by mostly wetter conditions to the 18th century (Figure 7c and h). However, the Wolf-62 record puts the end of the initial dry period about a century later than the Clear Pond record, and it suggests that the 'Little Ice Age' (LIA; c. AD 1350-1800; Jones et al, 2001;Maasch et al, 2005) was generally wetter than the MCA rather than similar or somewhat drier as was indicated for Clear Pond.…”

Section: Regional Hydroclimate Historysupporting

confidence: 81%

A 1600-year diatom record of hydroclimate variability from Wolf Lake, New York

et al. 2016

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A high-resolution diatom record from Wolf Lake, a minimally disturbed ‘heritage’ lake, provides insights into the hydroclimatic history of the Adirondack Mountains of northern New York during the last c. 1600 years. Three pronounced dry periods occurred during c. AD 490–610, 780–870, and 1010–1080, and low precipitation generally prevailed during the warm Medieval Climate Anomaly ( c. AD 950–1350), a finding that fills an important gap in knowledge of the spatial extent of droughts across North America during that period. During the cooler ‘Little Ice Age’ interval ( c. AD 1350–1800), inferred water balance was generally more positive. Seven peaks in charcoal abundance represent fire events during both wet and dry periods. Unusually high charcoal and inorganic sediment deposition c. AD 1700 could reflect human activity in the watershed, as might an abrupt rise in the relative abundances of planktonic and tychoplanktonic diatoms in Wolf Lake during the AD 1860s. The diatom record displays periodicities of c. 256 and 512 years in addition to high-frequency fluctuations, suggesting that significant precipitation variability is likely to continue to disrupt climatic trends in this region.

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“…Sediments from the deepest portion of the basin (>21 m) display rhythmic, fundamentally annual layering as reported by Gajewski et al (1987). The brown sediments pre-dating European settlement (assessed by pollen analysis) are finely and very regularly partitioned by thin, darker bands, which presumably represent winter layers.…”

Section: The Study Areasupporting

confidence: 58%

“…Annually laminated lake sediments provide the possibility of investigating magnetic parameters as high-resolution proxies of continental climate change. Lake Ely in northeastern Pennsylvania has deposited annually laminated sediments for at least 2000 yr (Gajewski et al 1987). The lake is located in a tectonically stable region and is far from heavily industrialized areas.…”

Section: Introductionmentioning

confidence: 99%

Bacterial magnetite produced in water column dominates lake sediment mineral magnetism: Lake Ely, USA

Kim¹,

Kodama²,

Moeller³

2005

Geophysical Journal International

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S U M M A R YEnvironmental magnetic studies of annually laminated sediments from Lake Ely, northeastern Pennsylvania, USA indicate that bacterial magnetite is the dominant magnetic mineral in the lake sediment. In previous studies of Lake Ely sediment, the dark, organic-rich layers in the annual laminae were interpreted to have high-intensity saturation isothermal remanent magnetizations (SIRMs) while the light-coloured, silt-rich layers have low-intensity SIRMs.To test the hypothesis that the magnetic grains in the sediments were an authigenic product of magnetotactic bacteria rather than detrital magnetic grains eroded from the watershed, we analysed samples from the water column, the lake sediment, and a sediment trap installed near the lake bottom. Direct microscopic observation of the water column samples showed the presence of magnetotactic bacteria in and below the oxic-anoxic transition zone (OATZ). To characterize the magnetic minerals, rock magnetic parameters were measured for material from the water column, the sediment trap and the dark-and light-coloured lake sediments. Lowtemperature magnetic measurements tested for the presence of magnetosomes in separated dark-and light-coloured layer samples. Numeric unmixing of the low-temperature results showed that biogenic magnetites were present in the lake sediment and contributed more significantly to the SIRM in the dark, organic-rich layers than in the light-coloured, inorganic silt-rich layers. Observations under the transmission electron microscope (TEM) of magnetic extracts also show the abundance of magnetosomes in the lake sediment. The presence of live magnetotactic bacteria in the water column and the predominance of bacterial magnetites in filtered particulate matter, sediment traps and recent lake sediment all suggest that bacterial magnetites are the main magnetic minerals in Lake Ely sediment. This finding suggests that changes in environmental factors that control the productivity of magnetic bacteria in the lake likely contribute to the variability of magnetic mineral concentrations observed in the lake sediments.

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Late Holocene Pollen Stratigraphy in Four Northeastern United States Lakes

Cited by 17 publications

References 34 publications

Ice-core records of biomass burning

Ice-core records of biomass burning

A 1600-year diatom record of hydroclimate variability from Wolf Lake, New York

Bacterial magnetite produced in water column dominates lake sediment mineral magnetism: Lake Ely, USA

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