Wikipedia:Reference desk/Archives/Science/2020 July 18

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July 18

Long-range dispersal of stromatoliths

I have a question about the bacteria that form living stromatolites. Is there any research out there about how these bacteria disperse and end up in places like Pavilion Lake and Lake Untersee? I have looked for such and didn't find anything. Jo-Jo Eumerus (talk) 20:44, 18 July 2020 (UTC)

It seems that these bacteria are no specific 'stromatolite bacteria', but that many different bacteria and algae and varied associations of these can build stromatolites given some suitable conditions. And possibly these same bacteria and algae are found everywhere on Earth but usually they just don't build stromatolites. So the question becomes how does any bacterium reach some specific location on Earth? Surely carried by water: [[1]] "Water is one of the most important bacterial habitats on Earth. As such, water represents also a major way of dissemination of bacteria ...". And wind would disperse bacterial spores over huge distances given that they can stay alive over centuries and even millennia, see e.g. endospore. 2003:F5:6F0F:6500:38C7:928B:9AB4:495F (talk) 23:22, 18 July 2020 (UTC) Marco PB

Soaring owls

Are there any owls that ridge soar - in particular over UK moorland? catslash (talk) 22:06, 18 July 2020 (UTC)

Owls are thought usually not to soar and actually they hunt by flying low and locate their prey using rather their ears than their eyes. But they are apparently able to soar occasionally, as for example reported here: [[2]]. Did you observe a soaring bird that you think could have been an owl? I suppose that an owl will soar sometimes maybe to fly back home, or will take advantage of a bright full moon night and open landscape to hunt by sight. 2003:F5:6F0F:6500:38C7:928B:9AB4:495F (talk) 22:55, 18 July 2020 (UTC) Marco PB

I did observe a large bird that seemed to have forward-looking eyes, soaring low over a small ridge a little above the highest field (~1600 ft) before the sun set on a west-facing slope. It drifted about, never flapping, loitering in my vicinity before drifting off along the ridge. It was pale and had a small tapering (as opposed to fan-shaped) tail. I had no camera. catslash (talk) 23:33, 18 July 2020 (UTC)

The two most likely pale coloured owls that you might see in the UK during the daytime are the barn owl and the short-eared owl. Mikenorton (talk) 21:53, 19 July 2020 (UTC)

Like this, but paler

So both pale, both frequent open country and both may be diurnal in the UK. The barn owl seems to have a very large face indeed, which makes the short-eared owl a better fit. It looked very much as in this picture, though paler. The wings were held somewhat back, not horizontally as in many soaring birds. It continually drifted about, never hanging motionless - perhaps conditions for soaring were not good, as neither the slope of the ground nor the wind speed were very great. Are there any non-owls this could have been? Or was it a soaring owl? catslash (talk) 00:28, 20 July 2020 (UTC)

The top picture in this article shows how pale the underside of the wings are in a short-eared owl. Still my best guess from your description - I can't think of another large pale bird showing that kind of behaviour, apart from the barn owl. Mikenorton (talk) 09:36, 20 July 2020 (UTC)

The very last picture in the same article shows an equally pale short-eared owl, with the wings extended, looking very similar to the bird I saw. It seems likely that it was indeed a soaring owl. Thank you for your help. catslash (talk) 15:28, 20 July 2020 (UTC)