Landscape-Scale Variability of Organic Carbon Burial by SW Greenland Lakes

Summary, in English

Lakes are a key feature of arctic landscapes and can be an important component of regional organic carbon (OC) budgets, but C burial rates are not well estimated.
²¹⁰
Pb-dated sediment cores and carbon and organic matter (as loss-on-ignition) content were used to estimate OC burial for 16 lakes in SW Greenland. Burial rates were corrected for sediment focusing using the
²¹⁰
Pb flux method. The study lakes span a range of water chemistries (conductivity range 25–3400 µS cm
⁻¹
), areas (< 4–100 ha) and maximum depths (~ 10–50 m). The regional average focusing-corrected OC accumulation rate was ~ 2 g C m
⁻²
y
⁻¹
prior to ~ 1950 and 3.6 g C m
⁻²
y
⁻¹
after 1950. Among-lake variability in post-1950 OC AR was correlated with in-lake dissolved organic carbon concentration, conductivity, altitude and location along the fjord. Twelve lakes showed an increase in mean OC AR over the analyzed time period, ~ 1880–2000; as the study area was cooling until recently, this increase is probably attributable to other global change processes, for example, altered inputs of N or P. There are ~ 20,000 lakes in the study area ranging from ~ 1 ha to more than 130 km
²
, although over 83% of lakes are less than 10 ha. Extrapolating the mean post-1950 OC AR (3.6 g C m
⁻²
y
⁻¹
) to all lakes larger than 1000 ha and applying a lower rate of ~ 2 g C m
⁻²
y
⁻¹
to large lakes (> 1000 ha) suggests a regional annual lake OC burial rate of ~ 10.14 × 10
⁹
g C y
⁻¹
post 1950. Given the low C content of soils in this area, lakes represent a substantial regional C store.

• Author: N. J. Anderson; P. G. Appleby; R. Bindler; I. Renberg; D. J. Conley; S. C. Fritz; V. J. Jones; E. J. Whiteford; H. Yang
• Department/s: Quaternary Sciences; BECC: Biodiversity and Ecosystem services in a Changing Climate
• Publishing year: 2019-12
• Language: English
• Pages: 1706-1720
• Publication/Series: Ecosystems
• Volume: 22
• Issue: 8
• Links: http://dx.doi.org/10.1007/s10021-019-00368-8
• Document type: Journal article
• Publisher: Springer
• Topic: Geosciences, Multidisciplinary
• Keywords: arctic; biogenic silica; diatoms; DOC; nitrogen; soil carbon; tundra
• Status: Published
• ISBN/ISSN/Other: ISSN: 1432-9840