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Lookup NU author(s): Dr Maarten van Hardenbroek van AmmerstolORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
The stable isotopic composition of chitinous remains of Cladocera (water fleas) and freshwater Bryozoa (moss animals) preserved in lake sediment records can provide supporting insights into past environmental and ecosystem changes in lakes. Here we explore whether analyses of these remains isolated from lake flotsam can provide information on the driving variables affecting the isotopic composition of these remains. We collected flotsam in 53 lakes and found enough material in 33 lakes to measure the stable carbon and nitrogen isotope ratios (expressed as d13C and d15N values, respectively) of resting stages. These values were compared with lake characteristics, water chemistry measurements, and the isotopic composition of sedimentary organic matter (SOM) in the lakes. Mean δ13C values of cladoceran ephippia and SOM were correlated and both were also negatively correlated with deep water methane concentrations and indicators of lake stratification. This supports the findings of previous studies that methane-derived carbon can provide a significant proportion of carbon entering planktonic food webs. Mean δ15N values of bryozoan statoblasts and SOM were correlated, suggesting that both reflect the δ15N values of phytoplankton. Our results provide information on how environmental variables in lakes can influence the d13C and d15N values in resting stages, but flotsam samples can also potentially be used to assess seasonal stable isotope variability of resting stages. Both types of information are important to improve palaeoenvironmental interpretations of stable isotope records based on these remains in lake sediments.
Author(s): van Hardenbroek M, Rinta P, Wooller MJ, Schilder J, Stötter T, Heiri OM
Publication type: Article
Publication status: Published
Journal: Quaternary Science Reviews
Year: 2018
Volume: 189
Pages: 187-196
Print publication date: 01/06/2018
Online publication date: 25/04/2018
Acceptance date: 06/04/2018
Date deposited: 21/04/2018
ISSN (print): 0277-3791
ISSN (electronic): 1873-457X
Publisher: Elsevier
URL: https://doi.org/10.1016/j.quascirev.2018.04.008
DOI: 10.1016/j.quascirev.2018.04.008
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