Influence of kelp forests on flow around headlands
Influence of kelp forests on flow around headlands
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海带森林对岬角周围水流的影响
DOI：
10.1016/j.scitotenv.2022.153952
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发表时间：
2022
影响因子：
9.8
通讯作者：
Monismith, Stephen G.
中科院分区：
文献类型：
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作者：
Valle-Levinson, Arnoldo;Daly, Margaret A.;Juarez, Braulio;Tenorio-Fernandez, Leonardo;Fagundes, Matheus;Woodson, C. Brock;Monismith, Stephen G.
海带森林影响沿海环流，但其对岬周围上升流的影响知之甚少。潮汐周期调查了两个岬角对比海带覆盖说明了海带森林对岬角上升流的影响。同时收集了航行中的声学多普勒海流和后向散射剖面，以测量表层水温。调查于2018年7月25日至29日在位于下加利福尼亚半岛西海岸中部的Isla Natividad附近沿沿着三个非岬样带进行。无海带覆盖的岬角附近的水流和水温分布与岬角上升流一致。与此相反，在海岬周围密集覆盖的海带：1）衰减的环境流; 2）有利于增加有效半径的流动曲率; 3）促进流动管道，其中包括增强流动通过渠道畅通的海带;和4）抑制海岬上升流。海带通过引导水流远离海岬来抑制上升流，使近岸沃茨比近海更温暖。特别是，这项研究描述了海带森林如何抑制通常在岬角周围发现的凉爽地下沃茨的向上泵送。这种地下沃茨注入的抑制通过我们称为“流动管道”的过程发生。在水流管道中，沿岸水流通过海带间隙形成通道，集中在宽度小于30 m的带中，并远离岬角的形态影响。这种管道类似于通过多孔介质的曲折流动。
Kelp forests affect coastal circulation but their influence on upwelling around headlands is poorly understood. Tidal-cycle surveys off two headlands with contrasting kelp coverage illustrated the influence of kelp forests onheadland upwelling. Underway acoustic Doppler current and backscatter profiles were collected simultaneously to surface water temperature. Surveys occurred along three off-headland transects in July 25–29, 2018, off Isla Natividad, located midway on the western coast of the Baja California peninsula. Flows and water temperature distributions off the headland with no kelp coverage were consistent withheadland upwelling. In contrast, the kelp around the headland with dense coverage: 1) attenuated the ambient flow; 2) favored an increase in effective radius of flow curvature; 3) promotedflow ducting, which consists of enhancing flow through channels unobstructed by kelp; and 4) suppressedheadland upwelling. Kelp suppressed upwelling by channeling the flow away from the headland, keeping nearshore waters warmer than offshore.Plain language abstractThis study documents a way in which biology can affect physics in coastal ocean environments. In particular, the study describes how a kelp forest suppresses the upward pumping of cool subsurface waters that is typically found around headlands. Such suppression of subsurface waters injection occurs via a process that we refer to as ‘flow ducting.’ In flow ducting, coastal flows are channelized through kelp gaps, concentrated in bands <30 m wide, and kept away from the morphological influences of a headland. This ducting is analogous to the tortuous flow through porous media.