The pervasive role of biological cohesion in bedform development.
The pervasive role of biological cohesion in bedform development.
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DOI：
10.1038/ncomms7257
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发表时间：
2015-02-06
影响因子：
16.6
通讯作者：
Thorne, Peter D.
中科院分区：
文献类型：
--
作者：
Malarkey, Jonathan;Baas, Jaco H.;Hope, Julie A.;Aspden, Rebecca J.;Parsons, Daniel R.;Peakall, Jeff;Paterson, David M.;Schindler, Robert J.;Ye, Leiping;Lichtman, Ian D.;Bass, Sarah J.;Davies, Alan G.;Manning, Andrew J.;Thorne, Peter D.
水环境中的沉积物通量主要取决于底形动力学。然而，沉积通量的预测几乎完全依赖于清洁的沙子的研究，尽管大多数环境是由非粘性砂，物理粘性泥浆和生物粘性的微生物产生的胞外聚合物（EPS）的混合物。已知与表面生物膜相关的EPS可稳定沉积物并增加侵蚀阈值。在这里，我们提出的实验数据表明，普遍分布的低水平的EPS在整个沉积物中，而不是高的survival水平的EPS在生物膜，是关键的控制床型动力学。对于极少量的普遍分布的EPS，底形的发展时间增加了两个数量级。这种影响远强于物理凝聚力，因为EPS抑制沙粒独立移动。结果表明，目前的底形预测过于简单，相关的泥沙输运过程需要重新评估EPS的影响。 凝聚力的作用对于我们理解沉积床型的演化是至关重要的。在这里，作者表明，沉积物中的微生物会影响凝聚力，并证明当存在胞外聚合物时，涟漪可能需要长达100倍的时间才能发展。
Sediment fluxes in aquatic environments are crucially dependent on bedform dynamics. However, sediment-flux predictions rely almost completely on clean-sand studies, despite most environments being composed of mixtures of non-cohesive sands, physically cohesive muds and biologically cohesive extracellular polymeric substances (EPS) generated by microorganisms. EPS associated with surficial biofilms are known to stabilize sediment and increase erosion thresholds. Here we present experimental data showing that the pervasive distribution of low levels of EPS throughout the sediment, rather than the high surficial levels of EPS in biofilms, is the key control on bedform dynamics. The development time for bedforms increases by up to two orders of magnitude for extremely small quantities of pervasively distributed EPS. This effect is far stronger than for physical cohesion, because EPS inhibit sand grains from moving independently. The results highlight that present bedform predictors are overly simplistic, and the associated sediment transport processes require re-assessment for the influence of EPS. The role of cohesion is vital to our understanding of how sedimentary bedforms evolve. Here, the authors show that microorganisms within the sediment affect cohesion and demonstrate that ripples can take up to one hundred times as long to develop when extracellular polymeric substances are present.
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影响因子：
64.8
作者：
GRANT, J;GUST, G
通讯作者：
GUST, G
影响因子：
2.8
作者：
GRANT, J;BATHMANN, UV;MILLS, EL
通讯作者：
MILLS, EL
影响因子：
5.4
作者：
Packman, AI;Brooks, NH;Morgan, JJ
通讯作者：
Morgan, JJ
影响因子：
4.5
作者：
Underwood, GJC;Paterson, DM;Parkes, RJ
通讯作者：
Parkes, RJ
影响因子：
2.3
作者：
Soulsby, R. L.;Whitehouse, R. J. S.;Marten, K. V.
通讯作者：
Marten, K. V.