A UFO an Unidentified Floating Object. It was not floating when Andrew Syred examined it with his scanning electron microscope (SEM) (Fig.1). It was found in a sample of water collected from a bog in Sutherland, Scotland, by Alan Joyce. It may have been floating and it is unidentified, unless that is I have the answer below.
Figure 1
I had sent part of the sample from Scotland to Andrew hoping he might provide a SEM photo' of a very small desmid new to Britain which I had found in the sample - an unnamed forma of Cosmarium tetrachondrum - the fine detail of which I could only see at 1000 x magnification with the optical microscope, being small only 26mm in width it was really a matter of luck if one ended up on a SEM stud. I was not lucky. However Andrew did provide a lot of interesting images among them the UFO.
Figure 2
After seeing the SEM images I search the sample using my Nikon Skt microscope and found the objects in the photo' (Fig. 2 ), there were others in pairs. They are spherical linked together by a stud and socket arrangement rather like some plastic beads I have seen. I believe they are oogonia broken away from a filament of Oedogonium spp (from the Greek oedos = swelling, and gonos = reproductive structure) I did not find any still attached to filaments, nor any with a dwarf male and anthredia attached which would have provided positive identification (Fig. 3a). Other species of Oedogonium have ellipsoidal oogonia.
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Figure 3. a) dwarf male, b) note projection inside filament. |
Are they the same organism as the UFOs ? maybe !, the cells are approximately the same sizes about 40mm. across. Compare the projection on the end of one of the cells in the SEM photo' with that in the drawing (Fig. 3b) where it is attached to the filament. My photo' of three cells are focused on the cell contents rather than the walls, the texture and the division into two parts shown in the SEM photo' cannot be seen.
Acknowledgements; many thanks to Alan Joyce for providing the samples and to Andrew Syred for the SEM images.
Reference; 'A Treatise on the British Freshwater Algae' G.S.West 1904 revised by F.E. Fritsch 1927. Pages 212-222.