Patterns in Nature: Alluvial Patterns

Another beach one! There is a small water discharge coming out of the sea wall near Tahunanui Beach, which when the tide is out, forms quite intricate and extensive braided river/delta patterns on the sand, but at a much smaller scale than a real braided river (making it much easier to capture the patterns!).

Could they be mountain ranges?

Seeing them reminds me of flying over the Sahara (on the Frankfurt to Abuja leg of the journey) on my way to Nigeria. Not because the patterns I saw were the same as these, but because I sensed the same scalelessness. Flying over the desert you can see the dunes, rocks, hills and valleys etc, but there is nothing for scale, until you start nearing more civilised areas nearer its edges. I got this sense that it was so enormously vast, until we flew over more habitable areas with roads and trees and realised that it wasn't really so vast as it had seemed (although it was still quite vast, and occupies the better part of whole countries!). Even though these patterns on the beach are over an area of just a few square metres, between the outlet and the tide, I get that same sense of scalelessness, that same sense of vastness, especially in these photos where I can cut out the surrounding scenery.

Or vast braided river patterns woven across the plains? 

I can just imagine this last one as hair. All it needs is a smooth spot of sand to the right of the photo, where one could draw a face on the sand :)

Patterns in Nature: Sand Dollars

At New Years I was walking along the beach at New Brighton with a friend, and we kept finding broken sand dollars on the sand... Sand dollars are a kind of sea urchin with flattened shells.

This one had two segments still stuck together, so shows the patterns better

When whole, the sand dollar consists of 5 segments, but we mostly found only single segments, but one or two with two segments still attached together. We thought the patterns on their shells were pretty neat. Below are some of the patterns in close up.

We also found one segment that had been broken to give a cross section of the inside...

Pretty, huh? 

If you want to learn more about sand dollars, This  page has some good info plus some cool videos of living sea urchins and sand dollars.