【被忽视的大气CO2源：土壤有机碳粉尘排放】Adrian Chappell1* Nicholas P. Webb2 Harry J. Butler3 Craig L. Strong4 Grant H. McTainsh4 John F. Leys45 Raphael A. Viscarra Rossel1. Soil organic carbon dust emission: an omitted global source of atmospheric CO2. Global Change Biology
Abstract
Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here we describe how SOC dust emission is omitted from national C accounting is an underestimated source of CO2 and may accelerate SOC decomposition. Similarly long dust residence times in the unshielded atmospheric environment may considerably increase CO2 emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO2-e yr−1) and Australian agricultural soils (0.4 Tg CO2-e yr−1). These amount to underestimates for CO2 emissions of ≈10% from combined C pools in Australia (year = 2000) ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore omission of SOC dust emission likely represents a considerable underestimate from those nations’ C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO2 from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.
【干旱引起的海水入侵导致湿地氮输出的增加】Marcelo Ardón1* Jennifer L. Morse2 Benjamin P. Colman3 Emily S. Bernhardt3. Drought-induced saltwater incursion leads to increased wetland nitrogen export. Global Change Biology
Abstract
Coastal w
