Rainfall pulse regime drives biomass and community composition in biological soil crusts
Rainfall pulse regime drives biomass and community composition in biological soil crusts
复制标题
降雨脉冲机制驱动生物土壤结皮中的生物量和群落组成
DOI：
10.1002/ecy.3744
复制
发表时间：
2022
期刊：
影响因子：
4.8
通讯作者：
Garcia‐Pichel, Ferran
中科院分区：
文献类型：
--
作者：
M. C. Fernandes, Vanessa;Rudgers, Jennifer A.;Collins, Scott L.;Garcia‐Pichel, Ferran
未来的气候将改变旱地降雨的频率和大小，潜在地影响向气候产生碳反馈的土壤微生物，但实地测试很少。旱地的表层土壤通常由生物土壤结皮(生物结皮)定居，生物结皮是以光合作用为基础的群落，提供从土壤施肥到稳定抗侵蚀的各种服务。我们量化了生物群落对12 年降雨制度变化的响应，在夏季季风季期间，每年以每周小雨(5 mm)或每月大雨(20 mm)的形式提供60 mm的额外降雨。降雨促进了微生物多样性，抑制了优势蓝藻和阴道微孔藻，增强了固氮类群，但并没有持续增加微生物生物量。许多小雨事件的增加增加了微生物生物量，而少数大型降雨事件则没有。这些结果改变了生理学范式，即生物结壳最受降雨量的限制，相反，预测在小雨事件中丰富的制度将促进蓝藻生物结壳，并增强其对旱地的有益服务。
Future climates will alter the frequency and size of rain events in drylands, potentially affecting soil microbes that generate carbon feedbacks to climate, but field tests are rare. Topsoils in drylands are commonly colonized by biological soil crusts (biocrusts), photosynthesis‐based communities that provide services ranging from soil fertilization to stabilization against erosion. We quantified responses of biocrust microbial communities to 12 years of altered rainfall regimes, with 60 mm of additional rain per year delivered either as small (5 mm) weekly rains or large (20 mm) monthly rains during the summer monsoon season. Rain addition promoted microbial diversity, suppressed the dominant cyanobacterium,Microcoleus vaginatus, and enhanced nitrogen‐fixing taxa, but did not consistently increase microbial biomass. The addition of many small rain events increased microbial biomass, whereas few, large events did not. These results alter the physiological paradigm that biocrusts are most limited by the amount of rainfall and instead predict that regimes enriched in small rain events will boost cyanobacterial biocrusts and enhance their beneficial services to drylands.