Shallow Water Tidal Ripple Patterns 11-14

Natural patterns on rippled water

Shallow Water Tidal Ripple Patterns 11-14 Photographs of natural patterns created by reflected sunlight on the crests of minor ripples in clear shallow seawater lapping with the incoming tide around the island of Burry Holms at the tip of the Gower Peninsula in South Wales. Here shown in negative format to highlight the intricacies of the natural designs.

Natural patterns on rippled water

Natural patterns on rippled water

Natural patterns on rippled water

Shallow Water Tidal Ripple Patterns 8-10

Natural patterns in rippled water

Shallow Water Tidal Ripple Patterns 8-10 Photographs of natural patterns created by reflected sunlight on the crests of minor ripples in clear shallow seawater lapping with the incoming tide around the island of Burry Holms at the tip of the Gower Peninsula in South Wales. Here shown in negative format to highlight the intricacies of the natural designs.

Natural patterns in rippled water

Natural patterns in rippled water

Iridescent Bacterial Films on Water

Natural abstract pattern in rainbow colours on the surface of water produced by iron-oxidising bacteria

The iridescent film on a small beach stream issuing from iron-rich volcanic rocks at Yachats in Oregon produced some lovely natural abstract patterns thanks to the colonies of iron-oxidising bacteria.

Strange Stream at Yachats – Part 1

Small stream with iron-oxidising bacteria

Following yesterday’s posting about a pond with a strange orange substance beneath shallow cloudy water, I received a most interesting comment suggesting that the orange colouring might not be decomposing algae as I had initially thought but the result of bacterial activity. Linda Grashoff has a special interest in iron-oxidising bacteria and has written many posts on the subject in her WordPress blog Romancing Reality, and she has written a beautiful and lavishly illustrated book about this fascinating topic. It is called “They Breathe Iron – Artistic and Scientific Encounters with an Ancient Life Form“. She said:

Your “something russet and mysterious” is indeed iron that has been oxidized and precipitated out of the water by the iron bacteria. The patches of pale blue film on top of the water—shown in the first and last photograph—are created by Leptothrix discophora, one of the iron-oxidizing bacteria. Other iron bacteria also oxidize iron in the water and are probably present along with the L. discophora on the edges of this pond. The L. discophora bacteria live at the air/water interface, with one end of their rod-shaped bodies in the air and the other end in the water. My guess is that the film keeps the tiny bodies oriented. As the microbes reproduce, they shove parts of the film over and under other parts, so that the film becomes thicker. Various film thicknesses produce various colors by light-wave interference, often resulting in the appearance of an oil slick.

This made me think about another occasion when I had encountered a strange little stream issuing from rocks at Yachats in Oregon on the west coast of America. It possessed a distinct iridescent film, and flowed across green photosynthesising organic matter that in places was coated orange. Bubbles of oxygen were trapped within the ?algae and beneath the film on the surface of the water. The rocks on the beach were rich in iron. The small stream must have been a good example of the activity of iron-oxidising bacteria in action.

This post shows a few photographs from that site – and more will follow tomorrow.

Iridescent film caused by iron-oxidising bacteria

Broken urface film caused by bacterial activity on the surface of a shallow stream

Oxygen bubbles from photosynthetic activity of green algae trapped below a broken surface film caused by bacteria

Oxygen bubbles from algae trapped below a bacterial film

Bubbles with orange iron deposit and bacterial film on the surface of a shallow beach stream

Bacterial film created by iron-oxidising bacterial with trapped oxygen bubbles from photosynthesising algae below.