<p>Writing about the San Francisco Bay salt ponds, <a href="http://chemconnections.org/general/chem120/solutions-mixes.html" rel="nofollow noreferrer">Dr R. J. Rusay notes</a>:</p>

<blockquote>
  <p>Due to variable algal concentrations, vivid colors, from pale green to bright red are created. The color indicates the salinity of the ponds.  Micro-organisms change their hues as the salinity of the pond increases.  In low to mid-salinity ponds, green algae are predominant. In middle to high salinity ponds, an algae called Dunaliella salina shifts the color to red. Millions of tiny brine shrimp create an orange cast in mid-salinity ponds. Other bacteria such as Stichococcus also contribute tints.</p>
</blockquote>

<p>Rusay says nothing about the Saloum Delta, but the explanation could be similar there.</p>

CC BY-SA 4.0
2019-07-01T14:11:16.340Z
This answer is supported by the [NASA Earth Observatory site](https://earthobservatory.nasa.gov/images/145216/salty-botswana)
Fred
CC BY-SA 4.0
2020-10-04T14:27:45.763Z
Additional support by [another webpage](https://earthobservatory.nasa.gov/images/147355/coloring-the-great-salt-lake) on the NASA Earth Obervation site.
Fred
CC BY-SA 3.0
2016-01-21T07:46:16.087Z
2017-01-05T08:55:54.603Z
2017-01-05T08:55:54.603Z
Mari wind fox
<p>What causes the different colours of the salts pits in the Saloum Delta in Senegal?</p>

<p><img src="https://i.sstatic.net/DYYKx.jpg" alt="enter image description here"></p>

CC BY-SA 3.0
2015-03-22T03:03:22.127Z
Could be bacteria? Different temperatures, salinites or other conditions could lead to different bacteria living there.
Gimelist
CC BY-SA 3.0
2015-03-22T06:31:46.213Z
I initially thought they might be dying pits like Sabre Tooth states, based on pictures of such pits in North Africa, but its difficult to know how large these pits are without a reference for scale. Michael's comment about bacteria is an interesting possibility. With the yellow, red, orange & brown pits one thought was different combinations of iron oxides, ferric & ferrous, but then I don't know how to explain the green pits.
Fred
CC BY-SA 3.0
2015-03-24T09:02:49.870Z
The delta is apparently a good example of an inverse delta, with very high salinity. So quite possibly this is an influencing factor?
mtb-za
CC BY-SA 3.0
2015-09-06T21:44:33.990Z
Don't know about these in particular, but the colors in [this image](https://en.wikipedia.org/wiki/Salt_evaporation_pond#/media/File:Salt_ponds_SF_Bay_(dro!d).jpg) are due to algae (greens) and halophillic bacteria (red, orange).  See [wikipedia](https://en.wikipedia.org/wiki/Salt_evaporation_pond) for more info.
rusty
<rivers><salinity>
What causes the different colours of the salt pits in the Saloum Delta in Senegal
Fred
# What causes the different colours of the salt pits in the Saloum Delta in Senegal

(Asked by: username_0 on 2015-03-21)

What causes the different colours of the salts pits in the Saloum Delta in Senegal?

![enter image description here](https://i.sstatic.net/DYYKx.jpg)

**Tags:** rivers, salinity

> **Comments:**
> **username_1**: Could be bacteria? Different temperatures, salinites or other conditions could lead to different bacteria living there.  
> **username_0**: I initially thought they might be dying pits like Sabre Tooth states, based on pictures of such pits in North Africa, but its difficult to know how large these pits are without a reference for scale. Michael's comment about bacteria is an interesting possibility. With the yellow, red, orange & brown pits one thought was different combinations of iron oxides, ferric & ferrous, but then I don't know how to explain the green pits.  
> **username_2**: The delta is apparently a good example of an inverse delta, with very high salinity. So quite possibly this is an influencing factor?  
> **username_3**: Don't know about these in particular, but the colors in [this image](https://en.wikipedia.org/wiki/Salt_evaporation_pond#/media/File:Salt_ponds_SF_Bay_(dro!d).jpg) are due to algae (greens) and halophillic bacteria (red, orange).  See [wikipedia](https://en.wikipedia.org/wiki/Salt_evaporation_pond) for more info.  

---

## 1 answers

### Answer by username_4 on 2016-01-21. Score: 4 | Accepted answer

Writing about the San Francisco Bay salt ponds, [Dr R. J. Rusay notes](http://chemconnections.org/general/chem120/solutions-mixes.html):

> Due to variable algal concentrations, vivid colors, from pale green to bright red are created. The color indicates the salinity of the ponds. Micro-organisms change their hues as the salinity of the pond increases. In low to mid-salinity ponds, green algae are predominant. In middle to high salinity ponds, an algae called Dunaliella salina shifts the color to red. Millions of tiny brine shrimp create an orange cast in mid-salinity ponds. Other bacteria such as Stichococcus also contribute tints.

Rusay says nothing about the Saloum Delta, but the explanation could be similar there.

> **Comments:**
> **username_0**: This answer is supported by the [NASA Earth Observatory site](https://earthobservatory.nasa.gov/images/145216/salty-botswana)  
> **username_0**: Additional support by [another webpage](https://earthobservatory.nasa.gov/images/147355/coloring-the-great-salt-lake) on the NASA Earth Obervation site.  

---

