Strontium concentration profiles (in ppm) for smelt caught in the Wadden Sea, going from the nucleus (left) to the outer edge (right).

The colours indicate the different hauls, all profiles in one colour originate from the same haul.不同颜色用以区分不同的拖次（haul），同一颜色对应的所有剖面数据均源自同一次拖次。