Please don’t wreck the wrack

by Edina Johnston

Seaweeds are crucial for a healthy environment and even when washed up on the shore, the “wrack” provides an important ecological link between the land and sea. Wrack provides food and shelter for a variety of beach inhabitants and even protects forage fish eggs from the heat of summer or cold of winter.

Recently, biologists found that about 40% of the invertebrate species living on beaches depend on wrack. These little creatures provide food for a variety of animals and birds.  Wrack is also a source of plankton, which feeds all the lower beach suspension feeders, enhancing the biodiversity and abundance of life along the coastline.

Wrack decomposes over time, releasing essential nutrients into the beach and acting as rich fertilizer for surrounding ecosystems. One study found that land plants near wrack grow 70% faster than plants without wrack nearby. These plants help stop erosion of the shore during the winter storms or  at extreme high tides. Another study found that decomposing wrack also provides nutrients for surfgrass and other plants that grow just offshore in the shallows which are crucial to smaller fish species.

When you remove the seaweed to use in your garden, you hurt the whole food web, from microscopic bacteria and humble marine isopods to the shorebirds and small mammals that feed on them. Winter storms will rebuild much of the seaweed cover, but because that build-up takes time, macro-invertebrate communities do not necessarily have the chance to bounce back, so please find alternatives for your garden. When our oceans die, so do we.