Storage of soil phytoliths and phytolith-occluded carbon along aprecipitation gradient in grasslands of northern China

• Climatic factors including mean annual precipitation (MAP) significantly influence the carbon (C) cycle interrestrial ecosystems and Earth overall. Phytolith-occluded carbon (PhytOC) is an important C sequestrationmechanism and as such plays a vital role in global long-term C sequestration. Understanding the spatialvariability in the storage of soil phytoliths and PhytOC and its relationship with climate is critical for evaluatingthe impact of global climate change on terrestrial ecosystem functions. However, little is known about theresponses of soil phytoliths and PhytOC to MAP in grassland ecosystems. This study sampled soil from 24natural, semi-arid steppe sites along a 2,500 km transect with a precipitation gradient of 243–481 mm yr−1 innorthern China. We investigated the influence of precipitation on the spatial distributions of soil phytoliths andPhytOC storage. Storage of soil phytoliths in bulk soil (0–100 cm depth) ranged from 21.3 ± 0.4 to88.4 ± 20.3 t ha−1 along the precipitation gradient. Amounts of soil phytoliths and PhytOC storage weresignificantly and positively correlated with MAP. Multiple regression analysis revealed that phytolith storage inbulk soil was best predicted by MAP (R = 0.5) and soil organic carbon (SOC, R = 0.4), with these two variablesaccounting for about 58% of the total variation observed. Considering the forecasted increase in MAP in theInner Mongolian steppe due to climate change, and the strong influence of MAP on the annual net primaryproductivity (ANPP) and related soil PhytOC input from litter decomposition in this region, we expect thatecosystem primary productivity will increase from deserts to meadow steppe and thereby promote soil PhytOCstorage. These findings have important implications for understanding the dynamics of soil phytoliths, andpredicting the impacts of global climate change on ecosystem functions and management practices in the EastAsian steppe ecosystems.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Soil phytolith

Mean annual precipitation

Stability

Mongolian Plateau

Miljövetenskap

Environmental Science

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