Elevated temperature increases the accumulation of microbial necromass nitrogen in soil via increasing microbial turnover. (1st July 2020)

• Record Type: Journal Article
• Authors: Wang, Xu; Wang, Chao; Cotrufo, M. Francesca; Sun, Lifei; Jiang, Ping; Liu, Ziping; Bai, Edith
• Is Part Of: Global change biology. Volume 26:Number 9(2020)
• Page Start: 5277
• Page End: 5289
• Publication Date: 2020-07-01
• Subjects: elevated temperature -- global climate changes -- microbial necromass -- nitrogen stable isotopes -- soil modeling -- soil nitrogen -- soil organic matter; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15206
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Microbial‐derived nitrogen (N) is now recognized as an important source of soil organic N. However, the mechanisms that govern the production of microbial necromass N, its turnover, and stabilization in soil remain poorly understood. To assess the effects of elevated temperature on bacterial and fungal necromass N production, turnover, and stabilization, we incubated 15 N‐labeled bacterial and fungal necromass under optimum moisture conditions at 10°C, 15°C, and 25°C. We developed a new 15 N tracing model to calculate the production and mineralization rates of necromass N. Our results showed that bacterial and fungal necromass N had similar mineralization rates, despite their contrasting chemistry. Most bacterial and fungal necromass 15 N was recovered in the mineral‐associated organic matter fraction through microbial anabolism, suggesting that mineral association plays an important role in stabilizing necromass N in soil, independently of necromass chemistry. Elevated temperature significantly increased the accumulation of necromass N in soil, due to the relatively higher microbial turnover and production of necromass N with increasing temperature than the increases in microbial necromass N mineralization. In conclusion, we found elevated temperature may increase the contribution of microbial necromass N to mineral‐stabilized soil organic N. Abstract : Microbial‐derived nitrogen (N) is now recognized as an important source of soil organic N. To assess the effects of elevated temperature on bacterial and fungal necromass N production, turnover, and stabilization, we incubated 15 N‐labeled bacterial and fungal necromass under optimum moisture conditions at 10°C, 15°C, and 25°C. We found that elevated temperature may increase the contribution of microbial necromass N to mineral‐stabilized soil organic N through the relatively higher microbial turnover and production of necromass N with increasing temperature than the increases in microbial necromass N mineralization.