DOI: 10.5061/dryad.cvdncjt49
title: Water residence time and temperature drive the dynamics of dissolved organic matter in Alpine lakes in the Tibetan Plateau

description: 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.
description: The
 dataset was collected during an investigation on the drivers of Dissolved
 Organic Matter in Alpine lakes in the Tibetan Plateau at the Nanjing
 Institute of Geography and Limnology, Chinese Academy of Sciences and
 Department of Geological Sciences, The University of Alabama.
 The
 data have been analyzed using a series of statistical tests (including
 non-parametric Kruskal-Wallis with Dunn post hoc test, spearman's
 bivariate correlations, redundancy analysis, and linear regression models)
 to produce a manuscript accepted for publication in Global Biogeochemical
 Cycles.
description: The
 readme file contains an explanation of each of the variables in the
 dataset, the associated measurement units, and -if it concerns a derived
 variable (displayed in grey) - the way it was calculated from the primary
 data (displayed in black). #NA = values not available. Information on how
 the measurements were done can be found in the associated manuscript
 referenced above.