Zostera beds typically occur in physically-sheltered environments
such as shallow inlets and lagoons. The plants stabilize the sediment within the beds and
the canopy of leaves reduces current flow (Fonseca and Fisher, 1986). However, increased
wave action and current flow, particularly during storms or floods, can remove sediments
and cause damage to the eelgrass beds.
Storms and hurricanes have been observed to remove large areas of Z.
marina (Wyer et al., 1977; Orth & Moore, 1983; den Hartog, 1987, Aio &
Komatsu, 1996). After storms, large amounts of Zostera material can be deposited on
the strandline of the shore. Fowler (1992) reported the degradation of Z. marina
beds around the Isles of Scilly following winter storms in 1989 and 1990. Floods can also
damage seagrass beds (Preen et al., 1995).
In extremely cold winters, the formation of ice amongst the sediments
of eelgrass beds can lead to the erosion of surface sediments as well as uprooting of
rhizomes and frost damage to foliage (Den Hartog, 1987). Critchley (1980) observed frost
damage to Zostera on the Isle of Wight.