Wednesday, 10 May 2017

The Wine-Dark Sea* (Tasmanian edition)


I was standing in the car park at Cloudy Bay, at the southern end of Bruny Island, binoculars over my shoulder, camera around my neck. I’d planned to stroll along the beach and photograph shorebirds, but a couple of 4WDs were racing across the sand. The gulls and oystercatchers scattered. I hoped the hooded plovers had taken refuge in the dunes.



The sea looked like red wine. Don’t ask me what type because I don’t read the boxes labels.



The coloration comes from algae, but it wasn’t a red tide**. The species tinting Cloudy Bay was almost certainly Asparagopsis armata, a rhodophyte (red alga). First described by Harvey (1855: 544) from Western Australia, it is native to southern Australia and New Zealand. Ships have spread it to temperate regions of the Northern Hemisphere



As with other algae, A. armata has a complex lifecycle. It goes through two major stages in which the forms are so unlike each other that they were originally thought to be different species: A. armata was applied to the branching form, and Polysiphona rufolanosa (Harvey, 1855: 540) to the filamentous one.



Recognising that this was not yer standard Polysiphona, Schmitz (1897) erected a new genus, Falkenbergia, with P. rufolanosa as type species. Bonin and Hawkes (1987) finally sorted out the situation, bringing P. rufolanosa into synonymy with Asparagopsis armata. I might have missed out some steps. Don’t @ me, algologists.

Silver gull, forest raven and sooty oystercatchers minding their own business


But the name Falkenbergia hasn’t disappeared from use. The filamentous form of A. armata is referred to as the Falkenbergia stage. And it is this stage that colours the waters of Cloudy Bay and turns the strandline red.



I didn’t know any of this at the time, of course. Which was probably just as well, because two people asked me if I had any idea about it, and I don’t think they were ready for an Ancient Mariner-style lecture about the intricacies of algal taxonomy. But next time…





* With no apologies to Homer

** Or a sign of the Apocalypse, although I’m not so sure about that one anymore.

References

Bonin, D.R. & Hawkes, M.W. (1987). Systematics and life histories of New Zealand Bonnemaisoniaceae (Bonnemaisoniales, Rhodophyta): I. The genus Asparagopsis. New Zealand Journal of Botany 25: 577-590.

Harvey, W.H. (1855). Some account of the marine botany of the colony of western Australia. Transactions of the Royal Irish Academy 22: 525-566.

Schmitz, F. & Hauptfleisch, P. (1897). Ceramiaceae. In: Die natürlichen Pflanzenfamilien nebst ihren Gattungen und wichtigeren Arten insbesondere den Nutzpflanzen unter Mitwirkung zahlreicher hervorragender Fachgelehrten, Teil 1, Abteilung 2. (Engler, A. & Prantl, K. Eds), pp. 481-504. Leipzig: verlag von Wilhelm Engelmann.

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