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  • 1
    ISSN: 1573-0417
    Keywords: Lake Arendsee ; Germany ; freeze-core ; eutrophication ; calcite ; near-infrared reflectance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The present study explored whether rapid, non-destructive near-infrared reflectance spectroscopy (NIRS) could complement conventional paleolimnological and chemical analyses of sediment cores for greater efficiency and cost-effectiveness. The study used a 47-cm long freeze-core from the deepest point in Lake Arendsee, Mecklenburg Plain in northern Germany taken in 1993 to elucidate eutrophication history and to identify the pre-impact algal communities in this system. The core had been analyzed for total C, CO32-, N, P, and diatoms. Thirty-four of the 47 1-cm thick core sections were scanned by NIRS and calibrations were developed for total C, CO32-, N, P, N:P, total diatoms, and three dominant diatom species with different sedimentary profiles (Stephanodiscus binatus, Cyclotella rossii, and Fragilaria crotonensis). Total C ranged from 167-194 mg g-1 dry weight (d.w.), CO32- from 31.3-66.4 mg g-1 d. w., N from 9.9-17.4 mg g-1 d. w., and P from 0.7-6.0 mg g-1 d. w. Calibrations developed using multiple linear regression between NIR-predicted values and chemically-measured values were excellent for P (r2 〉 0.99), good for C, N, and N:P (r2 〉 0.93), and satisfactory for CO32-(r2 〉 0.8). Calibrations for total diatoms and for individual species were highly statistically significant (r2 between 0.54 and 0.69). Although the calibrations are not useful for reliable predictions of the content of diatoms in the samples, the results indicate that NIRS detects spectral properties associated with diatoms or lake conditions when they were present, and that further work is warranted to attempt to improve the results. The study demonstrated that rapid, non-destructive, simultaneous analysis of total C, CO32-, N, P, and N:P in sediment cores is feasible.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of paleolimnology 19 (1998), S. 41-54 
    ISSN: 1573-0417
    Keywords: Lake Arendsee (Germany) ; paleolimnology ; nutrients ; eutrophication ; diatoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract To study the algal microfossil assemblages of eutrophic Lake Arendsee (Germany) prior to the beginning of a restoration project, a 47-cm long freeze core, dating back to ca 1800, was taken from the deepest area of the lake. Based on the CRS modeled 210Pb and 137Cs profiles from the core, 1948 is around 15 cm and the sedimentation rate has increased from ∼ 21.2 mg cm-2 yr-1 in 1900 to ∼ 56.6 mg cm-2 yr-1 in 1986. The sediments were dominated by three centric diatoms. Stephanodiscus binatus, a species associated with eutrophic environments, dominated the upper 19 cm of the core. Cyclotella rossii, a species commonly found in less productive freshwater systems, was found to dominate the lower portion of the core and was absent above 16 cm. S. agassizensis was found throughout the core. In addition to the centric diatoms, three penate diatoms were found to be abundant. Fragilaria crotonensis was found throughout the core, but was most abundant from 19 cm to 16 cm. Asterionella formosa was prevalent below 15 cm, while Diatoma elongatum was found to be common from 17 cm to the surface. The abundances of algal remains of cyanobacteria, chlorophytes, cryptophytes and dinoflagellates decrease dramatically below 25 cm. Zooplankton remains were most abundant around 20 cm, with copepod spermatophores, fecal pellets and protozoa remains most common in the lower portion of the core. The major species shifts observed in the core from Lake Arendsee occur in a transition zone between 20 cm and 15 cm (1920–1940), a time when agricultural production was being increase with the use of inorganic fertilizer.
    Type of Medium: Electronic Resource
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