After knowing this, I don't want to eat clam vermicelli casserole anymore

Review expert: Gu Ming Di Lian (He Lin) is a well-known science blogger on mollusks on Zhihu

Using animals to help humans with their work has been around since ancient times, from the earliest dogs guarding the house and cats catching mice, to the later use of birds and insects for biological control, and even dung beetles were once "invited" by humans to deal with related animal husbandry problems.

To give a simple example, Australia is a country with developed animal husbandry. After a long period of drying, the manure of cattle and sheep will eventually press down the grass, causing it to die. It will also cause flies and other pests to gather, which is harmful to humans.

To this end, Australia introduced dung beetles from China to deal with the proliferation of cattle and sheep manure, and the effect was very significant.

Kangaroo source: pixabay

But have you ever heard that such a major task as controlling a city's water valves can actually be entrusted to an animal? Not only that, this animal even has the important responsibility of monitoring the quality of drinking water?

The most incomprehensible thing is that this animal is actually a clam without a brain!

A clam with a big responsibility

Clams are a general term for bivalves in mollusks. As we all know, clams are a kind of aquatic mollusk with tender and delicious meat and rich nutrition. We usually see clams on the table in the form of stir-fry, which makes people salivate.

Source: pixabay

Clams, whose life stories sound a bit "miserable", can actually help humans use their natural abilities to detect whether water quality meets the standards!

Why is this?

It turns out that clams have extremely high requirements for water quality. When pollutants in the water exceed a certain standard, the clams will feel "uncomfortable" and then close their shells.

But is this method of testing water quality reliable? Many people have such doubts.

In fact, of course it is reliable.

This method has been developed through long-term observation and testing. The water treatment plant in Warsaw, Poland, uses river clams, which are also bivalves, to monitor water quality.

River clams have very strict requirements on water quality. They only live in very clean water and only open a small gap in their shells to find food and excrete. If they find any dangerous or irritating substances in the water, they will immediately close their shells.

Source: pixabay

Through research and observation, scientists have discovered that the opening and closing of clams' shells in response to changes in water quality is a stable behavior . In a stable environment, without interference from other organisms or foreign objects, the shells will not open and close at will depending on their "mood", which provides a theoretical basis for shellfish to detect water quality.

In order to avoid an accidental situation of a certain clam, which may lead to inaccurate measurement and give a wrong signal, scientists arrange eight clams at a time for testing. When the shells of four clams are closed, it can be considered that there is a problem with the water quality and a large amount of pollutants appear in the water, so the water valves of the entire city can be closed. It can be said that the clams shoulder the most critical link in this link and have a heavy responsibility.

The working process of clams

Under normal circumstances, each river clam can filter and analyze the water quality of 1.5 liters of water per hour. Although river clams in nature live in highly mobile water environments, in order to adapt to the work of monitoring urban drinking water environmental problems and face such a large flow of water every day, it is necessary to select adaptable river clams.

Source: See watermark

Moreover, each batch of clams selected from the river must undergo certain "professional training". Such "adaptation training" will last about two weeks before the clams can fully adapt to life in the water tank and begin to "test poison on themselves" for humans.

Each mussel that monitors water quality issues is placed in a special tank that contains a portion of the water that flows into the city in real time. The tank is connected to the system controller, which is connected to a computer and sends the real-time status of the mussel to the computer.

Source: See watermark

When multiple clams discover that the water is polluted and close their shells, the controller will immediately send this information to the computer, and the computer will send a closing command to the water valve. After receiving the command, the water valve will close the valve, thereby cutting off the polluted water and preventing it from flowing into the city's water supply system.

But humans need to rest when working, let alone river clams? There is always an adaptation period for different water qualities, which keeps them in a "working" state. Faced with a variety of different water quality changes, they need to judge whether the water meets their own water quality requirements and continue filtering and "analyzing". Even under long-term influence, river clams may have become accustomed to polluted water quality. Can such river clams still accurately identify pollutants in the water?

Source: tingclass.net

Therefore, scientists will not let a batch of river clams work all the time. According to Poland's experience, a batch of river clams can only "work" for three months at most, and then they will "retire" and take over.

The retired clams will be released back into the rivers and lakes where they were selected, and the clams that have contributed to the city will be marked accordingly to remind the staff who come to select the clams that the clams have been "retired". Please let them enjoy their "retirement" life and do not bring them to the table for "re-employment".