Cyanobacterial Soil Crust Responses to Rainfall and Effects on Wind Erosion in a Semiarid Environment, Australia: Implications for Landscape Stability
Cyanobacterial Soil Crust Responses to Rainfall and Effects on Wind Erosion in a Semiarid Environment, Australia: Implications for Landscape Stability
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DOI：
10.1029/2021jg006652
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
J. E. Bullard;C. L. Strong;H. Aubault
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文献类型：
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作者：
J. E. Bullard;C. L. Strong;H. Aubault
蓝藻生物结皮（CBCs）执行一系列功能，包括早期连续定殖的基质，土壤性质的修改，表面稳定和碳封存。对于养殖或单一物种，CBCs对水合作用的反应受到很好的限制，但对于原位群落则较少，并且很少有关于CBC对风蚀的反应和影响的研究。本文采用生物和物理指标研究了旱地生物碳对降雨和风蚀的原位响应。实地考察地点位于澳大利亚中部，有三种地貌状况-沙丘、nebkha和粘土。结果表明，较高的降雨量比较低的量引发更强烈的生物反应，但不是一个较长的时间。光合作用对降雨的响应强度似乎与气温有关。CBC和土壤风蚀流失之间的关系是不确定的，但跃移效率（Qs/Q）是最高的沙丘和粘土时，测试48小时后，施加5毫米的降雨。这是由于降雨使沙粒脱落，增加了地表松散的可侵蚀物质的可用性。结果突出了CBCs对降雨事件（数小时内）的快速生物反应，以及整体环境条件（如气温）的重要性，但对这种反应的生物影响的寿命提出了疑问。受干旱影响的CBCs可以保护地表免受风蚀，但脱水可能会降低对干扰的恢复力，并且在预测的未来气候情景下，蓝藻结皮的保护作用可能会受到损害。
Cyanobacterial biocrusts (CBCs) perform a range of functions including early successional colonization of substrates, modification of soil properties, surface stabilization and carbon sequestration. The response of CBCs to hydration is well‐constrained for cultured or single‐species but less so for in situ communities and there are few studies of CBC response to, and impact on, wind erosion. This paper investigates the in situ response of dryland CBCs to rainfall and wind erosion using biological and physical indicators. Field sites are in central Australia in three geomorphic situations ‐ sand dune, nebkha and claypan. Results indicate higher amounts of rainfall trigger a more intense biological response than lower amounts, but not one of longer duration. The intensity of photosynthetic response to rainfall appears related to air temperature. The relationship between CBC and soil loss by wind erosion is inconclusive, but saltation efficiency (Qs/Q) is highest on the dune and claypan when tested 48 hr after applying 5 mm of rainfall. This is attributed to rainfall detachment of sand particles increasing the availability of loose erodible material on the surface. The results highlight the rapid biological response of CBCs to rainfall events (within hours), and the importance of overall environmental conditions, such as air temperature, but raise questions as to the longevity of the biological impact of such response. Drought‐affected CBCs can protect the surface against wind erosion but dehydration may reduce resilience to disturbance and, under predicted future climate scenarios, the protective role of cyanobacterial crusts may be compromised.