Raadsel l/r sortering bij door de wind getransporteerde Myaschelpen opgelost

Riddle of left/right sorting in eolian transported Mya-shells solved. L/r sorting in a wind-blown assemblage of Mya arenaria valves was due to sorting in the source area, the tidal flat. Due to the presence of a large spoonshaped chondrophore projecting from the left valve, these valves remain “anchored” on the tidal flat, whereas the right valves lacking such a projection, accumulate at the highwater line. Valves remaining on the tidal flat are in the most stable position: concave-down. During low tide small waders, appropriately called turnstones, turn these shells in search of food. In the concave-up position the valves are now unstable and easily picked up by wind during a gale. The observed saltational transport brings even part of the shells over the 8-m-high dike bordering the tidal flat.