Effects of Temperature on Methane Production and Oxidation During Laboratory Incubation of Sediments from Meiziya Reservoir, China

Abstract

Methane (CH₄) emissions from reservoir to the atmosphere depend on the balance of microbial CH₄ production and oxidation, and temperature is an important factor to both processes by influencing directly the activity of microorganism. Six sediment cores of 30 cm were collected from the Meiziya Reservoir, China, a small water conservancy project with the maximum water depth of 9.7 m. The main input of reservoir was terrigenous organic matter, and the δ¹³C of organic matter in sediments ranged from − 27.5 to − 23.3‰. Using a self-made device for monitoring CH₄ production rate, we measured the CH₄ production and oxidation rates in sediment cores simultaneously at the range of 6–27 °C with an interval of 3 °C. The CH₄ net production rates and oxidation rates in sediment cores varied in the range of (4.2–2489.0) × 10⁻³ µmol/L·h⁻¹ and (16.0–1287.5) × 10⁻³ µmol/L·h⁻¹, respectively. Increasing temperature enhanced the CH₄ production and oxidation rates, and the former increased over temperature with an exponential trend. In the Meiziya Reservoir, a large proportion of CH₄ (69.7–70.6%) that originated from sediments was depleted before escaping to the surface sediments. During the mineralization of organic matter in sediments, the release of CH₄ accounted for 1.1–66.8% of gaseous carbon (calculated by the mass of C).