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           )

           Nowtheyhadthecircularrelationship:littlemakertopre-spicemass;littlemakertoshai-hulud;shai-huludtoscatterthespiceuponwhichfedmicroscopiccreaturescalledsandplankton;thesandplankton,foodforshai-hulud,growing,burrowing,becominglittlemakers.

           Kynesandhispeopleturnedtheirattentionfromthesegreatrelationshipsandfocusednowonmicro-ecology.First,theclimate:thesandsurfaceoftenreachedtemperaturesof344°to350°(absolute).Afootbelowgrounditmightbe55°cooler;afootaboveground,25°cooler.Leavesorblackshadecouldprovideanother18°ofcooling.Next,thenutrients:sandofArrakisismostlyaproductofwormdigestion;dust(thetrulyomnipresentproblemthere)isproducedbytheconstantsurfacecreep,the“saltation”movementofsand.

           Coarsegrainsarefoundonthedownwindsidesofdunes.Thewindwardsideispackedsmoothandhard.Olddunesareyellow(oxidized),youngdunesarethecoloroftheparentrock—usuallygray.

           Downwindsidesofolddunesprovidedthefirstplantationareas.TheFremenaimedfirstforacycleofpovertygrasswithpeatlikehairciliatointertwine,matandfixthedunesbydeprivingthewindofitsbigweapon:movablegrains.

           AdaptivezoneswerelaidoutinthedeepsouthfarfromHarkonnenwatchers.Themutatedpovertygrasseswereplantedfirstalongthedownwind(slipface)ofthechosendunesthatstoodacrossthepathoftheprevailingwesterlies.Withthedownwindfaceanchored,thewindwardfacegrewhigherandhigherandthegrasswasmovedtokeeppace.