Observaciones de davemmdave

Subject is the two irregular stone-like white objects, amongst some shells I've placed around them on the beach in front of the homestead accommodation. These are rhodoliths, beach washed. They are quite plentiful here.

A less dramatic example of this tendency for some species of drift brown macroalgae to develop bluish tinges during decomposition and decay. A prominent feature of the shallow littoral zone at various sites around Flinders Island but most easily observed at Home Beach Groper Bay, which is a relatively sheltered beach in the context of this island's generally very exposed and quite remote offshore position in the eastern GAB.

A good example of this bluish colour phenomenon that I discussed in a preceding observation from the same location.
Even in daylight some bluish tinting could be seen in the same sorts of drift and detrital seaweeds, but by moonlight it was more obvious and very appealing (I thought so, anyway, and so did my experienced companion wader and snorkeller).
Drift algae in shallows at low tide in littoral zone.

Night walk at low tide on the platform reef directly out front of the guests accommodation in Groper Bay. (The very small fish features in a separate observation of its type using photos from this same outing).

Nocturnal intertidal platform reef walk at low tide in front of the guests accommodation homestead, Home Beach. Subject is the brown to bluish grey drift algae most obvious in centre of 1st image. The photo, taken from above the surface in very shallow water, shows the colours as seen with the naked human eye, even in the moonlight and brightened with torch, flash or both. Presumably the bluish parts were fully brown when the plant was anchored by its holdfast, and the process of decay and pigment loss has caused the colour change. This was a very frequent phenomenon wrt the various forms of brown macroalgal drift weed and detrital fragments thereof. Some of the colours were wonderful to behold.

Dusk swalkel (finless snorkel) and a few minutes of actual snorkelling thrown together in this my last marine outing during this short stay on Flinders Island South Australia. The SUBJECT is the brown, upright, thready algae near frame centre. Presumably early growth stage Beanweed.
Home Beach platform reef, receding tide (another hour or so and the location would have been perfect for calm clear littoral zone pools and ledges, but dinner was being served:)

The epiphytic red algae on LHS is the subject of this observation..Growing on Posidonia blades mainly,,with minimal epiphytic growth in same size range seen on the coexisting Zostera species eel grass (presumably because this is a moderate to high exposure coastal site such that eel grass would be uprooted by surge once blades accumulated significant epiphytic loads, although the more rapid replacement growth rate of Zostera foliage might partly offset this). Snorkel close to the inshore limit of meadows at this location, Bull Ring Bay.

Mixed with some Zostera eel grass, near inshore limit of a meadow. Snorkel at Bull Ring Bay (which I've recently noticed has another place name on Google maps. However the island's owners (stewardship role taken seriously, BTW) use the Bull Ring Bay descriptor, so I have been guided by them for location names on Flinders Island).