Water residence time and temperature drive the dynamics of dissolved organic matter in Alpine lakes in the Tibetan Plateau

This dataset contains data from an investigation into the drivers on the
spatial distribution of dissolved organic matter in alpine lakes in the
Tibetan Plateau described in the paper: “Du Y., Chen F., Xiao K., Song C.,
He H., Zhang Q., Zhou Y., Jang K.-S., Zhang Y., Xing P., Liu Z., Zhang Y.
and Lu Y. 2021. Water Residence Time and Temperature Drive the Dynamics of
Dissolved Organic Matter in Alpine Lakes in the Tibetan Plateau, Global
Biogeochemical Cycles 35(11), e2020GB006908”.  The primary
objectives of the study were to: (i) evaluate the spatial variability of
the amount, source, and composition of DOM from alpine lakes on the
Tibetan Plateau, and (ii) determine the primary environmental controls and
mechanisms responsible for the spatial variability. At first, we collected
35 water samples from 25 lakes distributed in the northwestern (33.1–33.6
°N, 78.9–80.4°E), central (30.5–31.9°N, 88.3–89.4°E) and southeastern
(28.6–29.1 °N, 90.4–90.8°E) regions of the plateau. We characterized water
chemistry and DOM composition in these lakes by measuring dissolved
organic carbon (DOC) and DOM optical properties (i.e., absorbance and
fluorescence spectroscopy). DOM compositions of three lakes of different
water residence times (WRTs) were further analyzed using
ultrahigh-resolution molecular techniques (i.e., electrospray
ionization-assisted Fourier transform-ion cyclotron resonance mass
spectrometry, ESI FT-ICR MS). Secondly, we collected the indices of
climatic characteristics (i.e., mean annual temperature, mean annual
precipitation, and mean annual irradiation period) and lake hydrology
(i.e., catchment area, lake area, mean depth and water residence time) of
the sampling lakes. Thirdly, we performed statistical analysis to
determine the primary environmental control and predictors of the spatial
variability in lacustrine DOM on the Tibetan Plateau. The statistical
analyses included non-parametric Kruskal-Wallis with Dunn post hoc test,
spearman's bivariate correlations, redundancy analysis, and linear
regression models. Main results of this work are that (1) DOM in Tibetan
alpine lakes is mediated more by in-lake production and transformations
than by catchment inputs; (2) water residence time (WRT) of lakes
and mean annual temperature (MAT) accounted for 30–59% of the spatial
variance of the abundance of chromophoric DOM (CDOM) and fluorescent DOM
(FDOM); (3) Alpine lakes on the Tibetan Plateau would play a more active
and prominent role in regional and global carbon cycles in the face of
climate change.