近日，华东师范大学Fan Xu团队揭示微生物定植增加了对悬浮沉积物的阻力。2025年4月28日出版的《自然—地球科学》杂志发表了这项成果。
微生物群落和沉积物运输之间的动态相互作用塑造了大陆景观，并影响了地球表面的颗粒物通量。微生物定殖将单个沉积物颗粒转化为形态复杂多样的聚集体，使沉积物运输复杂化。然而，当前的模型通常会简化这种形态复杂性，假设聚集体经历的流体阻力等于光滑球体或理想形状的流体阻力。研究组应用X射线微计算机断层扫描方法结合计算流体动力学模拟，以高空间分辨率分析骨料形态，并确定与阻力的关系。
结果发现，与光滑表面相比，微生物定殖改变了细骨料的形态，使阻力增加了1-3倍，骨料尺寸或总体形状并不是阻力的主要控制因素。研究组提出了一种形态校正的阻力定律，解释了这种复杂性，调和了不同聚集体之间阻力的差异。该研究结果表明，从关注总尺度变化（大小或总形状）转向精细尺度形态，可以提高运输预测的准确性，并加深对河流、沿海和海洋系统中微生物定殖聚集体的理解。
附：英文原文
Title: Drag acting on suspended sediment increased by microbial colonization
Author: Zhang, Naiyu, Li, Haochen, Xu, Fan, Thompson, Charlotte E. L., Townend, Ian H., He, Qing
Issue&Volume: 2025-04-28
Abstract: The dynamic interplay between microbial communities and sediment transport shapes continental landscapes and influences particulate matter fluxes across the Earth’s surface. Microbial colonization transforms individual sediment grains into aggregates with intricate and varied morphologies, complicating sediment transport. However, current models often simplify this morphological complexity, assuming that aggregates experience fluid drag equal to that of smooth spheres or idealized shapes. Here we apply an X-ray micro-computed tomography method combined with computational fluid dynamics simulations to analyse aggregate morphology at high spatial resolution and determine the relationship with drag. Instead of aggregate size or gross shape being the primary controls on drag, we find that microbial colonization alters the fine-scale aggregate morphology and increases drag by factors of 1–3 compared with smooth surfaces. We propose a morphology-corrected drag law that accounts for this complexity, reconciling the differences in drag across diverse aggregates. Our findings suggest that a shift from focusing on gross scale variabilities (size or gross shape) to fine-scale morphologies could enable greater accuracy in transport predictions, and improve understanding of microbially colonized aggregates in fluvial, coastal and oceanic systems.
DOI: 10.1038/s41561-025-01679-3
Source: https://www.nature.com/articles/s41561-025-01679-3