Now visiting Beachmere : Trichodesmium Algal Bloom

Now visiting our shores: Trichodesmium spp.


Trichdesmium spp. \when washed ashore can appear red, brown or blue ..

Common names: Sea Sawdust; Sea Scum.

If you see what looks like an oil or paint spill on a beach between the months of August and December it is very likely that it is a bloom of Trichodesmium spp. This algae is generally not harmful but can look unsightly and produce a putrid ‘fishy’ odour. Ref.

 As Take Action for Pumicestone Passage points out:

“What does stimulate cell division and blooms in Trichodesmium is access to
bioavailable phosphorous, iron and COz. Being a cyanobacterium,
Trichodesmium is not limited by Nitrogen as it can fix that from the air. lt is,
however, limited by available phosphorous and iron, and COZ. Stormwater will, of
course, be a logical source of all of these whenever it drains from urban areas
where houses and fertilized lawns are built on acid sulphate soils. So it makes
sense that the initial inoculum of low density Trichodesmium from offshore would
bloom to extremely high/obnoxious cell densities when it has access to usually
limiting nutrients in stormwater from modified urban areas.”
With all of Golden Beach and surrounding suburbs in an area of Acid Sulphate
Soils, (ASS), this is an important consideration for all residents living in the
immediate catchment of Pumicestone Passage. Don’t use excessive fertiliser on
lawns and gardens and don’t allow water from gardens to run into
stormwater drains. Trichodesmium is most likely to appear between August and
December and that is probably the same time as we are developing our
“springtime” garden. Don’t waste water by allowing it run into the drain.

So go easy on the fertiliser. Given our sandy soil it is sure to run away anyway.The photograph was taken near the first drain north of Beachmere Rd.