It can be difficult to comprehend when we see this for the first time but the yellowish golden substance in the photo below is pollen from flowering plants.
Consistent wind directions over a number of days can accumulate pollen onto windward banks or corners within rivers and canals. The concentration of pollen can build up so significantly that it resembles a thick 'slick' like appearance with incredible colours. These slicks are mostly yellow in appearance and are often mistaken for paint. Locally, we often see swirled golden yellows and dull greens which reflect the colours of our local blossoms. The colour possibilities are endless and simply reflects the origin of the pollen.
Where does the pollen originate from?
Winter through to spring coincides with a significant flowering event within our native bushlands. Species of Acacia and Melaleuca bloom in their thousands and on windy days this pollen is lifted from flowers and can be carried long distances. As wind speeds decrease the particles begin to fall, generally we are unaware of this happening around us. It's when by chance it settles on water that we have an opportunity to observe this process.
Effects upon humans and the environment
While pollen can cause respiratory allergens in some people, it is far less likely to come into contact with people when wet and no longer air-borne. Pollen causes no environmental harm and is not hazardous to birds or fish.