Thursday, 5 September 2024

The Salt Lovers

 

Ever wondered why the Dead Sea is called so?

The Dead Sea is an inland saltwater lake, between Jordan and Israel. The lake receives most of its water from the Jordan River.


However, most of the fish carried by the Jordan River into the Dead Sea, are not able to survive. This is because the dead sea has a very high percentage of salts dissolved in it. In fact, it boasts of being the most saline water body on earth!

No forms of life can grow in this hostile environment, except certain bacteria that find highly saline environments favorable for their growth. These salt-loving microbes are called halophiles.

The halophilic bacteria grow in environments that have a concentrations of sodium chloride higher than that of sea water. These bacteria can survive in extreme conditions where very little nutrition is available. They also have a high resistance to the salts present around them and can balance the osmotic pressure of the environment.

Even the plants that grow along the coast of the dead sea, are those that prefer a high concentration of salt in the soil. These plants are called halophytes. Although sodium is not considered a key nutrient for most plants, halophytes show significant improvement in growth, in presence of sodium chloride.

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Friday, 16 February 2024

Patch or Soot?

We all know that pollution causes a lot of harm to the plants and animals around us. But did you know that some living beings can even be accurately reflect the levels of pollution in their surroundings? Due to this ability, they are often considered as reliable indicators of pollution, and are called bioindicators.

Well, these peculiar living beings are called lichens.


Lichens are formed by a symbiotic association between algae and fungi. In such an association, both the members help each other to thrive. The algae are plant like organisms that can prepare their own food by photosynthesis. They provide food to the fungi. The fungi cannot prepare their own food, but they can provide a structure and protection to the algae, which are otherwise delicate.

Lichens grow on barks of trees, often appearing as white patches. They are often called the mossy lichens.  

In highly industrialized areas, where air pollution by sulfur dioxide is common, lichens are unable to survive. In these areas, the barks of trees do not show the white patches of lichen. In fact, higher the levels of sulfur dioxide in the air, fewer the lichens seen on the trees. 

However, there is another kind of lichen, that is much more tolerant to air pollution and high levels of sulfur dioxide in air. This sturdier cousin of the mossy lichen is called the crusty lichen.

Areas where even these sturdier crusty lichens cannot grow, are considered very highly polluted.

In fact, the barks of trees in these highly polluted areas are often covered by black soot, which is also another air pollutant released by factories. Hence, instead of appearing white and patchy, the barks of trees appear black.

These lichens are our friends and have always warned us about pollution going above permissible levels. Although air pollution harms other living beings in the world, it harms humans too! We are wise enough to understand that we must save ourselves from the ill effects of pollution.  It is for us to not only decode the signals of these bioindicators, but also to save the entire ecosystem from the suffering due to actions of humans

Read more here...

air-quality.org.uk

britishlichensociety.org.uk