wrack line

The line of dried seaweed, marine vegetation, and other organic debris and detritus left on the beach by the action of the tides is called the wrack line. Tides strand the remains of marine creatures and sea grasses on the beach, including small invertebrates and bits of eelgrass. The wrack line may also contain man-made litter and refuse and is easily identifiable to the naked eye on that area of the beach where no plant life grows. Although there may be viable seeds hidden in the organic detritus of the wrack line, germination and seedling growth will typically occur only when a storm tide has left the debris at the highest and most landward edge of the beach, far out of reach of the daily high tides and waves. The wrack line serves as a prime feeding ground for birds and other animals that hunt here for food then defecate in the sand, providing organic matter essential to a strong ecosystem.

Jeffery Renard Allen