Ecosystem carbon storage and carbon metabolizing microorganisms in three types of grasslands on the Qinghai-Tibet Plateau.

The carbon storage of three grassland types followed the relativity of AW > AM > AD. Soil water content (SWC) was identified as the major factor affecting the carbon storage of grassland ecosystems by increasing vegetation belowground biomass and soil total carbon content, directly or indirectly influencing the diversity of four types of soil microorganisms through its effects on soil physicochemical properties. The community structure of these four types of carbon metabolizing microorganisms in AW significantly differed from that of AM and AD. The diversity of carbon-fixing microorganisms significantly reduced ecosystem carbon storage to a great extent. The relative abundance of carbon-fixing microorganisms <i>Thiobacillus</i>, <i>Mesorhizobium</i>, <i>Azospirillum</i>, and <i>Methylibium</i> significantly increased grassland carbon storage, while the relative abundance of chitinase-producing microorganisms <i>Cellulomonas</i> and <i>Stenotrophomonas</i> significantly decreased it.