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	<img alt="" src="{filedir_5}Langmuir Cells.jpg" style="text-align: center; width: 350px; height: 237px; float: right; " /></p>
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	<strong>Answer:</strong> &nbsp;Langmuir Spirals</p>
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	<strong>Background:</strong> Named after Irving Langmuir the spirals are created by the interaction between surface waves and wind-driven drift currents. Each spiral, normally only 1-5 meters in diameter (their diameter is normally equal to the depth of the thermocline), proceeds in the direction of the prevailing wind across the surface of the water, but rotating in a plane perpendicular to their direction (imagine a series of long corkscrews where the long axis is parallel to the wind). Each spiral rotates in a direction opposite that of the two neighbouring spirals, meaning you have a series of clockwise and counter-clockwise rotating spirals. The oppositional rotation of these spirals creates regularly spaced local zones ofupwelling and downwelling, which is what creates the peaks and troughs of the windrows.</p>
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	<span style="display: none;">&nbsp;</span><img alt="" src="{filedir_5}220px-Langmuir_Circulation.jpg" style="color: rgb(17, 17, 17); font-family: Verdana, Tahoma, 'Arial Unicode MS', sans-serif; text-align: center; width: 220px; height: 112px;" /><span style="display: none;">&nbsp;</span></p>
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	The downwelling flow is often between 2 and 8 cm s-1, much faster than the swimming capabilities of most zooplankton and phytoplankton. Thus, in the Langmuir spirals the biological organisms find themselves fairly thoroughly mixed. This mixing action creates zones of rich phytoplankton and bacteria concentrations. Many larger zooplankters (such as Daphnia, will migrate up to these zones and feed opportunistically. Following these zooplankton into these zones will be the planktivorous fish (such as the cyprinids -- minnows), and these in turn will be targeted by pelagic piscivores. These zones are, therefore, often good places for anglers to ply their trade.1</p>
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	Citation: 1.&quot;Langmuir Spiral.&quot; Everything2. N.p., 20 Jan. 2003. Web. 19 Mar. 2013.</p>
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	Diagram: Wikimedia Commons</p>
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	Photo: www.aslo.org</p>
