Diatom cell-size composition as a novel tool for quantitative estimates of water table in peatlands
- 1. China University of Geosciences
- 2. Northeast Normal University
Description
Diatom cell-size composition is an indicator of aquatic environmental changes, but has been rarely investigated, especially in semi-terrestrial peatlands. In this study, both taxonomic composition and cell-size composition of diatoms were analyzed in 41 samples from two montane peatlands, northeastern China. Redundancy analyses revealed that diatom taxonomic composition was significantly related to the depth to the water table (DWT) and Ca2+, while cell-size composition was significantly associated with DWT and Si. DWT was the most important factor and its sole effect explained 26.2% and 17.9% of the total variance in taxonomic composition and cell-size composition, respectively. Accordingly, diatom-based water-table transfer functions were developed based on taxonomic composition and cell-size composition, respectively. The maximum likelihood (ML) model based on diatom taxonomic composition had the best performance, with the correlation coefficient value (R2) of 0.78 and the root mean squared error of prediction (RMSEP) of 6.66 cm. The ML model based on cell-size composition had similar performance, with the R2 of 0.78 and the RMSEP of 6.87cm, suggesting that diatom cell-size composition can be a new quantitative means to track past water-table changes.
Notes
Funding provided by: National Natural Science Foundation of China
Crossref Funder Registry ID: https://ror.org/01h0zpd94
Award Number: U23A2003
Funding provided by: National Natural Science Foundation of China
Crossref Funder Registry ID: https://ror.org/01h0zpd94
Award Number: U20A2094
Methods
For diatom taxonomic composition, a minimum of 300 diatom valves were counted from each sample. Data of diatom taxonomic composition and environmental variables are sourced from our previous study. In this study, lengths of more than 300 diatom valves were measured in each sample using an Olympus BX53 microscope with 100 Plan N equipped with an Olympus DP27 digital camera and the cellSens software. The precision of the measurement is 0.1 μm. In order to establish diatom cell-size composition, all diatom valves are grouped in eighteen size classes at 2-μm intervals (i.e., 7-9 μm, 9-11 μm, 11-13 μm, etc). Large-sized diatoms with their valve lengths greater than 41 μm are rare and hence classified into one group. The species dataset comprises 32 main species (taxa with an abundance of at least 1% in at least one sample).