Flotation and dispersal of eelgrass seeds by gas bubbles

The formation of gas bubbles byZostera marina immediately prior to seed release is described together with evidence for its role as a seed dispersal mechanism. The gas bubbles, ranging in volume from 1.1 to 3.4 mm³, escape from the funiculus and adhere to the seed coat. As a bubble expands, the seed is pushed clear of the ovary and rises to the water surface with the bubble attached. Field data suggest that approximately 5–13% of the seeds produced are released with gas bubbles, and in some cases are transported more than 200 m (float time≥40 min).