Landcover map for the central region of the Yukon-Kuskokwim Delta, Alaska
Creators
- 1. Lamont-Doherty Earth Observatory
- 2. Woodwell Climate Research Center*
- 3. Harvard University
- 4. Columbia University
Description
Climate change is causing an intensification in tundra fires across the Arctic, including the unprecedented 2015 fires in the Yukon-Kuskokwim (YK) Delta. The YK Delta contains extensive surface waters (∼33% cover) and significant quantities of organic carbon, much of which is stored in vulnerable permafrost. Inland aquatic ecosystems act as hot-spots for landscape CO2 and CH4 emissions and likely represent a significant component of the Arctic carbon balance, yet aquatic fluxes of CO2 and CH4 are also some of the most uncertain. We measured dissolved CH4 and CO2 concentrations (n = 364), in surface waters from different types of waterbodies during summers from 2016 to 2019. We used Sentinel-2 multispectral imagery to classify landcover types and area burned in contributing watersheds. We develop a model using machine learning to assess how waterbody properties (size, shape, and landscape properties), environmental conditions (O2, temperature), and surface water chemistry (dissolved organic carbon composition, nutrient concentrations) help predict in situ observations of CH4 and CO2 concentrations across deltaic waterbodies. CO2 concentrations were negatively related to waterbody size and positively related to waterbody edge effects. CH4 concentrations were primarily related to organic matter quantity and composition. Waterbodies in burned watersheds appeared to be less carbon limited and had longer soil water residence times than in unburned watersheds. Our results illustrate the importance of small lakes for regional carbon emissions and demonstrate the need for a mechanistic understanding of the drivers of greenhouse gasses in small waterbodies.
Notes
The data type for the landcover map is integer, with 0 = no data (includes areas outside the research watershed and a small area where and old fire scar reburned in 2015 that could not be mapped),
1= lichen dominant tundra on peat plateaus, some graminoids and prostrate dwarf shrubs
2= degrading permafrost on peat plateaus (either sparse but productive wetland graminoid, exposed mud, or shallow water, depending on antecedent rainfall)
3= vegetated wetland (peat fens, often with small channels and adjacent sphagnum bog or mosses underlying graminoids), lower in elevation relative to peat plateaus
4= shrub tundra, often the 'banks' or edges of peat plateaus
5= tundra at the edges of degrading permafrost on peat plateaus, often wetter and more liekly to be dominated by sphagnum species and sphagnum fuscum
6= vegetated wetland (fens, but darker green, possibly tall shrubs. This was lumped with category 3 for most analyses), lower in elevation relative to peat plateaus.
7= waterbody edges; including unvegetated shoreline and areas with emergent vegetation and surface water
8= sedge tundra on peat plateaus (often the near the edges of plateaus or more sloped areas of plateaus)
9= low severity 2015 fire scar (peat plateaus). Includes small pockets of unburned within the fire scar.
10= 2015 fire scar tundra at plateau edges (similar to category 8 in unburned)
11= 2015 fire scar peat plateau
12= 2015 fire scar vegetated wetland (peat fens)
13= 2015 fire scar degrading permafrost (similar to category 2 unburned)
14= Old fire scar peat plateau edges (similar to category 8 unburned)
15= Old fire scar vegetated wetland (peat fens)
16= Old fire scar water edge (similar to category 7 unburned)
17= Old fire scar degrading permafrost (similar to category 2 unburned)
18= Old fire scar tundra peat plateau
19= Old fire scar tundra peat plateau, but more abundance of shrubs and graminoids
20= Waterbodies (includes those in unburned and all fire scars)
Funding provided by: National Aeronautics and Space Administration
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100000104
Award Number:
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Additional details
Related works
- Is cited by
- 10.1029/2021gb007146 (DOI)