Fine-scale dynamics of calcite precipitation in a large hardwater lake.
Details
Serval ID
serval:BIB_642221FE6747
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Fine-scale dynamics of calcite precipitation in a large hardwater lake.
Journal
The Science of the total environment
ISSN
1879-1026 (Electronic)
ISSN-L
0048-9697
Publication state
Published
Issued date
15/03/2023
Peer-reviewed
Oui
Volume
864
Pages
160699
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Publication Status: ppublish
Abstract
In hardwater lakes, calcite precipitation is an important yet poorly understood process in the lacustrine carbon cycle, in which catchment-derived alkalinity (Alk) is both transformed and translocated. While the physico-chemical conditions supporting the supersaturation of water with respect to calcite are theoretically well described, the magnitude and conditions underlying calcite precipitation at fine temporal and spatial scales are poorly constrained. In this study, we used high frequency, depth-resolved (0-30 m) data collected over 18 months (June 2019 - November 2020) in the deeper basin of Lake Geneva to describe the dynamics of calcite precipitation fluxes at a fine temporal resolution (day to season) and to scale them to carbon fixation by primary production. Calcite precipitation occurred during the warm stratified periods when surface water CO <sub>2</sub> concentrations were below atmospheric equilibrium. Seasonally, the extent of Alk loss due to calcite precipitation (i.e., [30-42] g C m <sup>-2</sup> ) depended upon the level of Alk in surface waters. Moreover, interannual variability in seasonal calcite precipitation depended on the duration of stratification, which determined the volume of the water layer susceptible to calcite precipitation. At finer timescales, calcite precipitation was characterized by marked daily variability with dynamics strongly related to that of planktonic autotrophic metabolism. Increasing daily calcite precipitation rates (i.e., maximum values 9 mmol C m <sup>-3</sup> d <sup>-1</sup> ) coincided with increasing net ecosystem production (NEP) during periods of enhanced water column stability. In these conditions, calcite precipitation could remove as much inorganic carbon from the productive layers as NEP. This study provides mechanistic insights into the conditions driving pelagic calcite precipitation, and quantifies its essential contribution to the coupling of organic and inorganic carbon cycling in lakes.
Keywords
Calcite precipitation, Lake Geneva, Alkalinity, High-frequency, Inorganic carbon, Net Ecosystem Production, Alkalinity, Calcite precipitation, High-frequency, Inorganic carbon, Lake Geneva, Net Ecosystem Production
Pubmed
Web of science
Publisher's website
Open Access
Yes
Funding(s)
Swiss National Science Foundation / Projects
Create date
01/02/2023 11:08
Last modification date
04/04/2023 7:11