This exquisite object, nature's equivalent of a Fabergé egg but only about one tenth of a millimetre long, is a testate rhizopod - a species of amoeba that lives inside a balloon-shaped shell. Testate rhizopods either secrete their shells or they cement minute sand grains together to create one. When you think about it, that's a remarkable feat of construction for one of the lowest forms of life that, superficially, is little more than a slithering blob of cytoplasm. You can see some more examples here. Testate rhizopds that assemble a shell from sand grains are often assigned to the genus Difflugia and scores of 'species' have been described, based on the components and construction of their shell, although it's not clear to what extent these are really distinct 'species'. You can download a guide to identification and where to find them here. I found this specimen when I was screening a sample of water from amongst the waterweeds on the edge of a pond in Durham. I have to admit that the image above has involved a bit of optical trickery because.........
... this is what I saw when I first examined the organism under normal bright field microscopy, revealing the translucent quartz grains that formed its case. Switching to dark field microscopy....
... where the image is formed from light diffracted by the translucent grains showed them in a new light. But it was only when I switched to polarised light microscopy, which reveals the interference colours formed by the birefringent grains, that the ultimate beauty of this tiny organism's case was revealed.
Jewellery on a microscopic scale...
Fascinating and informative as always. Such a lot to be seen in microscopic life forms. The polarised light certainly makes a difference.
ReplyDeleteHow beautiful! What a difference the polarized light makes...
ReplyDeleteHi John and Falltoclimb, it is amazing how polarised light can transform simple objects...
ReplyDeleteAwesome photos; Difflugia is also awesome for sometimes using diatom valves for its test!
ReplyDeleteI do however object to calling amoebae "one of the lowest forms of life" -- amoebae are at the exact same "height" as vertebrates and bacteria, and we should really stop perpetrating this awful scala naturae misconception...
Point taken, Psi Wavefunction - my apologies to the amoeba clade (do they have lawyers too?) for this slur on their rightful evolutionary status. I guess it’s just my journalistic roots showing through: ‘lowly form of life’ has a nice alliterative ring to it and, in the excitement of a personal discovery, the mask of scientific propriety sometimes slips. Maximum respect to amoeba and their ancient - and in no way evolutionarily inferior – clade. It one of my cells could do what they do, selecting just one particular kind of particle from the ooze to coat its exterior in such an aesthetically pleasing way, I’d be damn proud.
ReplyDeletewow, but all of the images are startlingly beautiful!
ReplyDeleteHi Zoe,they really are amazing organisms
ReplyDelete