I’m taking time during lockdown to catch up on some papers that I had been meaning to write for some time. One of these, for a special issue of the journal Ecological Indicators, is about the diatoms of Cyprus, a subject that I’ve touched upon in a few earlier posts (see “Diatoms from the Troodos Mountains”). Writing about Cyprus, even via the dry prose of an academic paper, reminded me how much I had enjoyed earlier visits, and when I might be able to return.
Most of the hard work to produce the data in this paper was, I have to admit, done by Marco Cantonati and, in the process, he has found several species that had not previously been described, which makes us wonder if the endemism for which the higher plant flora of Cyprus is well-known also extends to the diatoms. There has been a vigorous debate about the extent to which diatoms are cosmopolitan rather than restricted to particular geographic areas in recent years, with evidence now to show that some species definitely seem to be cosmopolitan whereas others are much more localised in their distribution. The diatom flora of an island such as Cyprus ought to be a valuable test case for this.
One species that we had not seen before but which, after searching the literature, Marco was able to match with a previously-described species was Achnanthidium tepidaricola – shown in the picture at the top of the post. Achnanthidium is a large genus of small diatoms, and we have only really started to appreciate the diversity within the genus over the past 20 years or so (see “Quantifying our ignorance …”). This particular species, however, has a story to tell. It was first found growing on a wet stone wall in a greenhouse in the National Botanic Garden in Meise, Belgium by Bart van der Vijver a few months after the wall had been constructed. Finding the same species in Belgium and Cyprus ought to be a hint that it is relatively cosmopolitan. However, our story has an interesting twist …
The twist is that the wall that Bart sampled in the greenhouse in Meise was built with stones that had been imported from Turkey. Suddenly, A. tepidaricola is looking less Flemish and more like a migrant. Turkey is, of course, the nearest mainland country to Cyprus, and shares the same arid climate of the eastern Mediterranean. Many of the streams in this part of the world will, naturally, dry out in the summer and the diatoms will have to be prepared to survive in these conditions. Suddenly, A. tepidaricola growing both in Cyprus and on that one particular wall in Belgium is looking less like evidence of endemism and more like a hint that, even if not endemic to Cyprus, this species may be characteristic of the eastern Mediterranean. It may be more widespread than that, but this is certainly where it is being recorded at the moment.
That’s the trouble with biogeography: the distribution of species is forever shifting, and our modern joined-up world only accelerates this process. Dump a pile of stones from Turkey almost anywhere else in Meise and the Flemish climate would probably have sent Achnanthidium tepidarociola to the Great Biofilm in the Sky. But these particular stones were put into a greenhouse where they were able to thrive and, eventually, to be noticed by Bart. Humans helping previously unknown bugs to move across the world? Where else have I heard about that before?
The photo at the top of this post was taken by Marco Cantonati and shows a population of Achnanthidium tepidarocola from Vyzakia, Cypris in March 2019.
Van der Vijver, B., Jarlman, A., Lange-Bertalot, H., Mertens, A., de Haan, M. & Ector, L. (2011). Four new European Achnanthidium species (Bacillariophyceae). Algological Studies 136/137: 193-210.
Some other highlights from this week:
Wrote this whilst listening to: 1980s Bob Dylan (probably not his greatest period): Empire Burlesque and Knocked Out Loaded. Also an elderly, rather scratchy recording of Rachmaniov’s first two piano concertos with Rachmaniov himself on piano. And Scottish singer-songwriter Siobhan Wilson’s There Are No Saints. Well worth checking out, if you have never heard her before.
Cultural highlights: Jojo Rabbit. This one split the critics but was a box office hit. There were too many negative reviews when it first came out for us to make the trip out to see it but our son persuaded us to give it a try. Glad we did. Very clever soundtrack.
Currently reading: HG Well’s War of the Worlds.
Culinary highlight: Caesar Salad, from a Felicity Cloake recipe in The Guardian. We also found some pumpkin lurking in the depths of the freezer and turned it into a pie. Ate both whilst sitting in the garden: a rare treat in our climate.