top of page

Underwater Trails and Purple Bushes - Olhão Mysteries

A recent session with Google Maps turned up a couple of mysteries for me. First, the above tracks in the mud off of Ilheu do Alcorao, on the coast of Olhão. Clearly, this is some animal at work, but which one? A fish? A mollusc? It's got to be something pretty big, as you can see by reference to the wee 14 m wide beach. The tracks extend further, but this is the densest region I could find.

I spend a fair bit of time checking out this environment, transition from sea to land between Faro and Olhão. It's a fascinating place with incredibly stark contrasts. Man-made settling pools constructed for salt production sit cheek-by-jowl with the mud flats, marshlands and estuary of the Ria Formosa, a big part of which is a internationally renowned nature reserve.

Bucket List Item: Multiple days with very high spf waterproof sunscreen and an underwater camera, snorkeling around in this area. I would be very curious to know how deep these waters are; in many places it looks like only a matter of inches. The clarity of the water, combined with the sinuous action of water flow on mud and substrate create gorgeous fractal seascapes. As a bonus, "the Ria Formosa has one of the highest seahorse densities in the world, which makes it an ideal spot to observe them in their natural habitat" (MPAs Portugal).

The salt pans present a subtle spectrum of hues and shapes, human geometry breaking down into organic textures upon close inspection. Neither wet nor dry, they are an interstitial zone of many colours, and also home to the perhaps-not-so-mysterious-after-all purple bushes:

Searching Google for "purple bushes salt Olhão" hasn't solved the mystery as to why these salt-hardy plants have turned purple, but I can make a guess. The key is that not all of the bushes are purple, and there are varying degrees of purple. It looks as though they are being turned purple by their immediate environment, namely all the salts in it. The hues of the settling ponds suggest that the salts contain coloured minerals (or maybe different species of algae?) that manifest in the vegetation. The question remains as to why that particular shade of purple overall, given so much colour variation in the pools locally.

I don't know what the name of this plant is, but it is everywhere, also away from the salt pans and out in the wild where it is sometimes not purple (see above).

Becky in Portugal has a good blog article about the salt industry in the Algarve, Portugal’s white gold.

Here is the website for a company that produces salt in this area: Salinas do Grelha, offering "Dead Sea" bathing. Sounds like fun.

The above two photos used with permission from the Salinas do Grelha website.

I will be posting many more Google Map satellite views of this area because it is so damn beautiful.

***Edit: July 13, 2020***

A couple of views using the new Google Earth:

37 views0 comments

Recent Posts

See All


bottom of page