DOI: 10.5061/dryad.sj3tx968t
title: Physical characteristics and chemical measurements of northern lakes in western Canada

description: Northern lakes disproportionately influence the global carbon cycle and
 may do so more in the future depending on how their microbial communities
 respond to climate warming.  Microbial communities can change
 because of the direct effects of climate warming on their metabolism and
 the indirect effects of climate warming on groundwater connectivity from
 thawing of surrounding permafrost, especially at lower landscape
 positions. Here we used shotgun metagenomics to compare the taxonomic and
 functional gene composition of sediment microbes in 19 peatland lakes
 across a 1600-km permafrost transect in boreal western Canada. 
 We found microbes responded differently to the loss of regional permafrost
 cover than to increases in local groundwater connectivity. These results
 suggest that both the direct and indirect effects of climate warming,
 which were respectively associated with loss of permafrost thaw and
 subsequent changes in groundwater connectivity, interact to change
 microbial composition and function. Archaeal methanogens and genes
 involved in all major methanogenesis pathways were more abundant in warmer
 regions with less permafrost, but higher groundwater connectivity partly
 offset these effects.  Bacterial community composition and
 methanotrophy genes did not vary with regional permafrost cover, and the
 latter changed similarly to methanogenesis with groundwater
 connectivity.  Finally, we found an increase in sugar utilisation
 genes in regions with less permafrost, which may further fuel
 methanogenesis. These results provide the microbial mechanism for observed
 increases in methane emissions associated with loss of permafrost cover in
 this region and suggest that future emissions will primarily be controlled
 by archaeal methanogens over methanotrophic bacteria as northern lakes
 warm. Our study more generally suggests that future predictions of aquatic
 carbon cycling will be improved by considering how climate warming exerts
 both direct effects associated with regional-scale permafrost thaw and
 indirect effects associated with local hydrology.
description: This table contains seasonal and daily field and laboratory data
 for samples collected from 19 lakes in Alberta and the Northwest
 Territories between 2018 and 2019. General information includes lake name,
 permafrost region, location coordinates, size and depth. Meteorological
 information includes mean annual precipitation, mean annual air
 temperature, precipitation and pressure. Chemical measurements are the
 average of measurements taken over the entire 2018–19 sampling period.
 Daily measurements for specific conductivity (COND) are also reported.
 Chemical parameters measured were: water temperature, dissolved oxygen,
 specific conductivity, pH, dissolved organic carbon, total nitrogen, ions
 (Na, Mg, K, Ca, Mn, Fe, Cu, Zn, P, S, NH<sub>4</sub>,
 NO<sub>3</sub> Cl, PO<sub>4</sub>,
 SO<sub>4</sub>), chlorophyll A. Further information regarding
 units and descriptions of each parameter can be found under the “Sample
 Information” tab in the spreadsheet.