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| Drag increase and drag reduction found in phytoplankton and bacterial cultures in laminar flow: Are cell surfaces and EPS producing rheological thickening and a Lotus-leaf Effect? | |
| Jenkinson, Ian R.1,2; Sun, Jun1,3; Jenkinson, IR (reprint author), Chinese Acad Sci, Inst Oceanog, Key Lab Marine Ecol & Environm Sci, 7 Nanhai Rd, Qingdao 266071, Peoples R China. | |
| 2014-03-01 | |
| 发表期刊 | DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
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| 卷号 | 101页码:216-230 |
| 文章类型 | Article |
| 摘要 | The laminar-flow viscosity of ocean and other natural waters consists of a Newtonian aqueous component contributed by water and salts, and a non-Newtonian one contributed mainly by exopolymeric polymers (EPS) derived largely from planktonic algae and bacteria. Phytoplankton and EPS form thin layers in stratified waters, often associated with density discontinuities. A recent model (Jenkinson and Sun, 2011. J. Plankton Res., 33, 373-383) investigated possible thalassorheological control of pycnocline thickness (PT) by EPS secreted by the harmful dinoflagellate Karenia mikimotoi. The model, based on published measurements of viscosity increase by this species, found that whether it can influence PT depends on the relationship between increased viscosity, deformation rates/stresses and length scale, which the present work has investigated. To do this, flow rate vs. hydrostatic pressure (and hence wall stress) was measured in cultures (relative to that in reference water) in capillaries of 5 radii 0.35-1.5 mm, close to oceanic-turbulence Kolmogorov length. We compared cultures of the potentially harmful algae, K. mikimotoi, Alexandrium catenella, Prorocentrum donghaiense, Skeletonema costatum, Phaeodactylum tricornutum and the bacterium Escherichia colt. Drag increase, ascribed to rheological thickening by EPS, occurred in the smallest capillaries, but drag reduction (DR) occurred in the largest ones. Since this occurred at Reynolds numbers Re too small for turbulence (or turbulent DR) to occur, this was laminar-flow DR. It may have been superhydrophobic DR (SDR), associated with the surfaces of the plankton and bacteria. SDR is associated with the self-cleaning Lotus-leaf Effect, in which water and dirt are repelled from surfaces bearing nm- to mu m-sized irregularities coated with hydrophobic polymers. Because DR decreased measured viscosity and EPS thickening increased it, we could not validate the model. DR, however, represents hitherto unknown phenomenon in the oceans. Along with rheological thickening, Laminar-Flow DR may represent a new tool for plankton to manage ambient flow fields. (C) 2013 Elsevier Ltd. All rights reserved. |
| 关键词 | Phytoplankton Rheology Turbulence Dissolved Organic Matter Oceanic Microstructure Pycnocline |
| 学科领域 | Oceanography |
| DOI | 10.1016/j.dsr2.2013.05.028 |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000334141700018 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qdio.ac.cn/handle/337002/24006 |
| 专题 | 海洋生态与环境科学重点实验室 |
| 通讯作者 | Jenkinson, IR (reprint author), Chinese Acad Sci, Inst Oceanog, Key Lab Marine Ecol & Environm Sci, 7 Nanhai Rd, Qingdao 266071, Peoples R China. |
| 作者单位 | 1.Chinese Acad Sci, Inst Oceanog, Key Lab Marine Ecol & Environm Sci, Qingdao 266071, Peoples R China 2.Agcy Consultat & Res Oceanog, F-19320 Lavergne, La Roche Canill, France 3.Tianjin Univ Sci & Technol, TEDA, Coll Marine Sci & Engn, Tianjin 300457, Peoples R China |
| 第一作者单位 | 中国科学院海洋研究所 |
| 推荐引用方式 GB/T 7714 | Jenkinson, Ian R.,Sun, Jun,Jenkinson, IR . Drag increase and drag reduction found in phytoplankton and bacterial cultures in laminar flow: Are cell surfaces and EPS producing rheological thickening and a Lotus-leaf Effect?[J]. DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY,2014,101:216-230. |
| APA | Jenkinson, Ian R.,Sun, Jun,&Jenkinson, IR .(2014).Drag increase and drag reduction found in phytoplankton and bacterial cultures in laminar flow: Are cell surfaces and EPS producing rheological thickening and a Lotus-leaf Effect?.DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY,101,216-230. |
| MLA | Jenkinson, Ian R.,et al."Drag increase and drag reduction found in phytoplankton and bacterial cultures in laminar flow: Are cell surfaces and EPS producing rheological thickening and a Lotus-leaf Effect?".DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY 101(2014):216-230. |
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