Mysterious algae is spreading in all water reservoirs in the world

The invasive algae "Didymo" behaves strangely, but it turned out that man does not spread it, but the damage he causes to the environment facilitates its absorption

Researchers from Australia and the United States publish in the journal "The study of the diatomA report on the strange algae that appears all over the world and is spreading, a strange green creature that spreads in rivers and clogs streams.

It started in 1998 with some small spots that stuck to rocks in the Haber River in Canada. Within a year, the spots thickened and a green covering was formed that the researchers call mucus (snots), which for a few years grew to a huge area.

After about a decade the slimy "creature" was identified throughout America, Europe, Asia and Australia, the slimy creature that continues to spread was identified as an algae from the diatom group - and a species known from fossils and called - Didymosphenia geminate, being so strange it was given the nickname Didymo - Didymo.

Of course, the first people to be blamed for the spread of the creature were people, it was said that "fishermen move it in their vessels from river to river, boaters spread the algae with boats and other equipment."

There are places where algae creates a slimy carpet and clogs water passages, which requires expenses for cleaning and evacuation, but to date the damage to the didimos is negligible. It turns out that there is a strange story behind the appearance of Didymo acceleration. When the scientists sought to identify it, to understand how it behaves and what causes its sudden spread, it became clear to them that the appearance is not sudden at all.

We are familiar with the term "algae bloom" when a certain algae multiplies rapidly mainly because of nutrients in the water, the rapid multiplication causes the water surface to become clogged and a lack of oxygen. There are algae that secrete toxins and thus the term "algae bloom" is known as a negative event that causes the death of fish and other animals.

It turns out that Didymo's spread is not a rash and is not necessarily a negative event. The researchers describe the green cover as an "elixir-induced metamorphosis" that is not similar to the known and accepted reproductive characteristics (in algae), since it is possible that the green slime is not an acute problem but just a marker that shows problems and changes that are occurring in rivers and streams all over the world .

It turned out that, unlike other algae (diatoms), they changed form from a benign "growth" that is not harmful to "something malignant and evil", the single-celled creature sends out groups of mucous webs that become entangled and form a mucous carpet that covers beach rocks and water. That is, it is not cell division but a change in the existing cells.

Contrary to what was initially thought (distribution by man), it turns out that algae has always been widespread in large areas on all continents except Africa. This is according to fossils identified at the bottom of bodies of water. In other words, the thought that was accepted is that algae is a species that has been distributed in recent times or a species that expands its area of ​​distribution and multiplies (explosive species). In recent years it has become clear that this thought is wrong.
Therefore the question arises, what causes the "explosion" of the didimo population? It turns out that unlike other algae that "bloom" because of the richness of nutrients in the water (mainly phosphorus derivatives). Didymo becomes "malignant" when the water has very little phosphorus, that is, water poor in nutrients causes changes in didymo cells and the appearance of the green carpet.

In the last five decades, governments and environmental organizations have been trying to stop the algae bloom that chokes rivers by reducing phosphorus pollution, this with the belief and knowledge that the algae feed on phosphorus derivatives, but it turns out that this is exactly what causes the "poverty" of the water, which encourages the development of Didymo's green slime.
And yet there is one place where the didimo may be an invasive species - in New Zealand. A decade ago, a small patch of green slime appeared down a river in the South Island, in a place frequented by fishermen and kayakers, since its appearance the didimo has spread throughout the island. The question is asked (again) whether Didimo was in New Zealand before 2004? Was it simply undetected or was it imported? Since no (historical) evidence was found for the reality of Didimo Bay, it was probably imported, since its appearance coincides with the increase in tourism traffic. The rivers in the southern island where clean water flows from the east "were virgin territory for Didimo" which grew, developed and sent the green slime.

Since 2004 New Zealand has declared war on the small diatom and many believe that the authorities' activity will succeed in preventing its spread to the North Island. There are those who think otherwise, the origin of the soil of the northern island is ash and volcanic rocks from which a soil rich in phosphorus is obtained. The assumption is that the phosphorus that "saturates" the rivers prevents the spread of the didymo, which means that the didymo may have reached the North Island, but due to incompatibility - rich in phosphorus, it does not spread there, the simple way to check the various assumptions is to check for fossil remains from the bottom of the rivers, but this is an expensive test Therefore it has not yet been carried out.

The obvious question arises - does the Didimo endanger the environment? Is he a threat to disaster? For fishermen and boaters who struggle with the green slime, the question is not academic as they want to know if the didimo harms fish and invertebrates such as insects - on which the fish depend. It turns out not, the diatom continues to surprise, researchers have shown that its spread stimulates the population of small insects such as flies, wasps and mosquitoes but causes a reduction in the amount of large insects such as dragonflies and midges and it turns out that the fish switch to eating the small insects without it affecting them negatively.

According to the researchers, despite the fact that the effect of didymo is different in different regions, the environmental damage is minimal and yet there are places where the green slime covers rivers and the repulsive color alone can damage activities such as fishing and boating, as well as pumping water. And again it turns out that the didimo is not poisonous and its main effect is the strange appearance of the water.

So where is the problem? According to the researchers, the problem is not the spread of the didimo in the world and its takeover of the world's rivers, the problem is that the didimo is a primary marker of a disturbed environment, a marker of man's influence and damage to fresh water bodies and environmental systems.
The researchers explain how people cause damage to the rivers and enable the development of the didymo:

- Use of mineral fuel such as oil and coal increases the amount of nitrogen in the atmosphere. The nitrogen causes creatures in the soil to use phosphorus... meaning less phosphorus reaches the rivers.
- An increase in the use of nitrogen-rich fertilizers in agriculture and forestry causes the same reaction.
- The climate changes cause changes in the length of the seasons and the advance of snow melting. Melting snow dilutes the concentration of phosphorus in freshwater systems.

All these are changes caused by man, changes that promote the spread of Didimo. It is possible that the direct causes of the spread of the didimo vary in different places or that the factors have a combined effect, in any case the researchers declare that "we have met the invader and he is not the didimo but ... us".

And here of course I will add that the time has come that instead of controlling the environment for the sake of the human population, there will be control of the human population for the sake of the environment.