Mineral weathering and soil development in the earliest land plant ecosystems
Mineral weathering and soil development in the earliest land plant ecosystems
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DOI：
10.1130/g38449.1
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发表时间：
2016-12-01
期刊：
影响因子：
5.8
通讯作者：
Kenrick, Paul
中科院分区：
文献类型：
--
作者：
Mitchell, Ria L.;Cuadros, Javier;Kenrick, Paul
在古生代，植物及其真菌和细菌共生体的陆地殖民化是陆地生态系统演化的基础，但这些早期群落如何影响矿物风化和土壤发育仍然是未知的。我们调查了隐花植物地被植物（CGC）在冰岛，以确定现代类似的社区和表征土壤结构和生物介导的风化特征。使用一种新的应用X射线显微计算机断层扫描，我们表明，苔藓为主的CGC和他们的土壤是不足够的模拟早期社区。与407马Rhynie燧石（苏格兰）生物群的比较表明，现代CGC为主的地衣，地钱，及其相关的共生体（真菌，蓝藻）是更有代表性的早期成土社区。地钱和地衣土壤很薄，其深度和复杂性受到主要植物或地衣的大小和生长形式的限制。它们被蓝细菌、菌根和地衣化真菌、假根和相关分泌物聚集和稳定。蒙脱石与地钱，但不与苔藓CGC土壤。土壤颗粒溶解特征是多种多样的，可归因于不同的生物（例如，细菌，真菌）和相互作用的类型（例如，共生）。我们假设，这些功能提供了一种新的间接手段推断古土壤中的生物相互作用。
Land colonization by plants and their fungal and bacterial symbionts during the Paleozoic was fundamental to the evolution of terrestrial ecosystems, but how these early communities influenced mineral weathering and soil development remains largely unknown. We investigated cryptogamic ground covers (CGCs) in Iceland to identify modern analogous communities and to characterize soil structure and biologically mediated weathering features. Using a novel application of X-ray microcomputed tomography, we show that moss-dominated CGCs and their soils are not adequate analogues of early communities. Comparisons with the 407 Ma Rhynie Chert (Scotland) biota indicate that modern CGCs dominated by lichens, liverworts, and their associated symbionts (fungi, cyanobacteria) are more representative of early soil-forming communities. Liverwort and lichen soils are thin, and their depth and complexity are constrained by the size and growth form of the dominant plants or lichens. They are aggregated and stabilized by cyanobacteria, mycorrhizal and lichenized fungi, rhizoids, and associated exudates. Smectite was associated with liverwort but not with moss CGC soils. Soil grain dissolution features are diverse and attributable to different organisms (e.g., bacteria, fungi) and types of interaction (e.g., symbiosis). We postulate that such features provide a novel indirect means of inferring biotic interactions in paleosols.