The Northern Beaches has been hit with a surge of smelly seaweed this week, amid a sweltering heatwave, with beachgoers’ only options being to wait it out or swim among the algae.
The washed-up kelp has spread across the local coastline, but has primarily affected Dee Why and Collaroy Beach, plus South Steyne at Manly leaving much of its sand covered with piles of seaweed, some over a metre in height.
The plant debris is likely to release increasingly potent rotten egg like smells as the week heats up – Saturday temperatures predicted to reach 40 degrees – causing the seaweed to decompose faster and release hydrogen sulfide.
If you’re a Northern Beaches local, you may have been told growing up that the common influx of seaweed from Dee Why to Collaroy is due to large kelp beds growing off a sunken 19th-century ship, the SS Collaroy. A tall tale, as the wreck was resurfaced years ago.
The scores of seaweed inhabiting Northern Beaches shores this time around are most likely associated with huge swells that hit the NSW Coast over the New Year period, causing kelp seabeds to dislodge and wash up on shores. Big waves also cause sand to become depleted on the shoreline.
In previous years, Northern Beaches Council would rake the beaches with large tractors; however, these activities are suspended as the seaweed serves an important coastal process.
“Seaweed is not removed from any beach as it is a natural part of the beach environment,” Council stated.
“During large surf events, the kelp beds off the coast are dislodged and inevitably wash up along our many beaches.”
Seaweed benefits coastal systems in a variety of ways. Structurally, it provides support where big surf has caused large amounts of ground mass to be lost, while providing the remaining sand with additional nutrition. The stranded seaweed also provides wildlife with a temporary habitat and food source.
Although this common marine algae may not be the most pleasant of seaside companions, try to keep an open mind to the services it provides when you’re setting up a towel near a potent pile. After all, you’re not the only one who lives for the beach.
