Eutrophication and Geochemistry Drive Pelagic Calcite Precipitation in Lakes
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Kuupäev
2021
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
MDPI
Abstrakt
Pelagic calcification shapes the carbon budget of lakes and the sensitivity of dissolved
inorganic carbon (DIC) responses to lake metabolism. This process, being tightly linked to primary
production, needs to be understood within the context of summer eutrophication which is increasing
due to human stressors and global change. Most lake carbon budget models do not account for
calcification because the conditions necessary for its occurrence are not well constrained. This study
aims at identifying ratios between calcification and primary production and the drivers that control
these ratios in freshwater. Using in situ incubations in several European freshwater lakes, we identify
a strong relationship between calcite saturation and the ratio between calcification and net ecosystem
production (NEP) (p-value < 0.001, R2 = 0.95). NEP-induced calcification is a short-term process that
is potentiated by the increase in calcite saturation occurring at longer time scales, usually reaching the
highest levels in summer. The resulting summer calcification event has effects on the DIC equilibria,
causing deviations from the metabolic 1:1 stoichiometry between DIC and dissolved oxygen (DO).
The strong dependency of the ratio between NEP and calcification on calcite saturation can be used
to develop a suitable parameterization to account for calcification in lake carbon budgets.
Kirjeldus
Märksõnad
calcite precipitation, eutrophication, metabolism, geochemistry, lake carbon budge, primary production, alkalinity, calcite saturation, articles