14/01/2026
What's that!?
Our team was called to investigate a thick brown 'sludge' at the Coffs Harbour Jetty area today. This 'sludge' was identified as Trichodesmium erythraeum. Trichodesmium erythraeum algal blooms are natural phenomena commonly known as "sea sawdust" or "sea scum". These blooms appear as vast, oily-looking slicks of rusty-brown, yellow, or pinkish material floating on the ocean surface. Blooms typically occur when sea surface temperatures exceed 24–27°C and coincide with extended periods of still weather, which allow the buoyant algae to aggregate at the surface. Blooms typically last from a few days to several weeks, depending on environmental conditions. They play a crucial role in marine ecosystems due to their ability to convert atmospheric nitrogen into a form that is usable by marine organisms. Health authorities advise avoiding swimming, surfing, or wading in affected water and to rinse thoroughly if exposed, as these blooms can cause skin irritation, rashes, stinging, and respiratory issues (similar to hay fever) upon contact.
