The pervasive role of biological cohesion in bedform development

被引：194

作者：

Malarkey, Jonathan ^{[1
]}

Baas, Jaco H. ^{[1
]}

Hope, Julie A. ^{[2
]}

Aspden, Rebecca J. ^{[2
]}

Parsons, Daniel R. ^{[3
]}

Peakall, Jeff ^{[4
]}

Paterson, David M. ^{[2
]}

Schindler, Robert J. ^{[5
]}

Ye, Leiping ^{[3
]}

Lichtman, Ian D. ^{[1
,6
]}

Bass, Sarah J. ^{[5
]}

Davies, Alan G. ^{[1
]}

Manning, Andrew J. ^{[3
,5
,7
]}

Thorne, Peter D. ^{[6
]}

机构：

[1] Bangor Univ, Sch Ocean Sci, Menai Bridge LL59 5AB, Anglesey, Wales

[2] Univ St Andrews, Sch Biol, Sediment Ecol Res Grp, St Andrews KY16 8LB, Fife, Scotland

[3] Univ Hull, Dept Geog nvironm & Earth Sci, Kingston Upon Hull HU6 7RX, N Humberside, England

[4] Univ Leeds, Sch Earth & Environm, Leeds LS2 9JT, W Yorkshire, England

[5] Univ Plymouth, Sch Marine Sci & Engn, Plymouth PL4 8AA, Devon, England

[6] Natl Oceanog Ctr, Liverpool L3 5DA, Merseyside, England

[7] HR Wallingford, Wallingford OX10 8BA, Oxon, England

来源：

NATURE COMMUNICATIONS | 2015年 / 6卷

基金：

英国自然环境研究理事会;

关键词：

SAND-MUD; SEDIMENT; EROSION; EPS; ERODIBILITY; EXOPOLYMERS; PREDICTION; EXCHANGE; BIOFILMS; SYSTEMS;

D O I：

10.1038/ncomms7257

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

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.

引用

页数：6

共 36 条

[1]

Allen J., 1984, Sedimentary structures, their character and physical basis

[2] RIPPLE GENERATION UNDER THE COMBINED INFLUENCES OF WAVES AND CURRENTS ON THE CANADIAN CONTINENTAL-SHELF [J].