Anaerobic respiration and temperature response along a boreal
hydrological transect on a slope from upland forest to peatland
Abstract
Climatic warming is predicted to affect high-latitude habitats, such as
boreal peatlands, at a larger magnitude than the global average. The
controls on the breakdown of organic matter in peatlands are complex;
it’s unclear how climatic warming will affect the stability of the large
carbon pool that’s currently stored in peatlands. To investigate this,
we collected soil cores from three boreal habitats along a hydrological
transect (Bog, Intermediate, and Upland Forest) in Finland, and
incubated ex-situ for 140 days. Each soil horizon was incubated in three
temperatures (0°C, 4°C, 20°C). Here, we found the Intermediate site had
the largest CO2 production considering the entirety of the soil column
(per gram dry weight). Statistical analysis found that sample C content
was the most indicative independent variable to predict sample CO2
production. Each soil horizon displayed a different magnitude of
response to the temperature incubations (Q10s ranged from 0.60-2.33),
and through microbial relative abundance analysis we found that the
microbial community structure had significant differences between both
habitat and depth of sample origin. Coupling these methods, and the fine
scale of the both vertical (soil column horizons) and horizontal (along
a hydrological gradient through distinct habitats) transects gives us a
novel perspective on the controls of microbial respiration rates. Our
results stress that large scale modeling efforts of carbon dynamics
should prioritize both soil carbon quantity and quality.