The clam you had for lunch may be hundreds of years old.

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There are only two kinds of creatures in the world-those that already appear in the species calendar and those that will appear in the species calendar. There are not only some strange "cold knowledge", but also rich "mind-wandering" natural science popularization. A species every day will show you the world.

In 2006, a group of British scientists went on a research cruise in Icelandic waters. When the big net lowered by the ship rowed across the sea floor, the creatures inhabiting the sea floor were immediately taken away from the sea floor. This network has allowed scientists to harvest a number of valuable experimental samples, including the Arctic round clam, the longest-lived mollusk known to mankind.

Arctic round clam "bright" specimen | Bangor University

Clams also have "annual rings".

The first time scientists saw Ming, they did not find it special. This clam looks ordinary and is 8.7 centimeters long, no different from other big clams that can be played on the palm of the hand. But when they counted the growth rings on its shell, everyone was stunned.

The growth pattern on the inside of the shell | Rob Witbaard

However, this method of calculating age has strong limitations, because Ming's age is so old that the growth rings are superimposed one after another, while the clam itself almost stops growing after reaching a certain age. More than 500 rings are squeezed on a surface of only a few millimeters, which causes some growth rings to be too close to each other or too flat, which can easily lead to observation errors.

Ring after ring on the Arctic round clam shell | Hans Hillewaert / Wikimedia Commons

In 2013, scientists decided to reassess Ming's age, this time using more advanced and sophisticated measurements such as carbon-14 dating. The new count rose to 507 years old, a full century more than before. Scientists are confident of the accuracy of the assessment, saying that the error will only be within 1-2 years.

Arctic round clam washed ashore | nz_willowherb / Flickr

The "Secret Book of longevity" of clams

The emergence of Ming brings more than surprises.

While its news dominated the headlines, criticism and scolding followed: "there is nothing more ironic than killing the world's oldest animal to calculate its age!"

An Arctic round clam obtained in Str mstad, Sweden | Karlafg / Wikimedia Commons

Due to the need to preserve biological samples, all clams were frozen at low temperature soon after they were caught and then transported to the laboratory for research, and the possibility of survival after frozen transportation was very low, the researchers explained. The 200 clams collected account for only a small part of the population.

Arctic round clams (and other seafood) on the Norwegian market | Wolfmann / Wikimedia Commons

In terms of probability, the possibility that Ming is the longest-lived animal in the world is actually "very small", and older clams are likely to still be lurking somewhere in the depths of the ocean.

A 2011 study showed that it is not uncommon for arctic clams to be over 100 years old, with individuals over 100 years old found in waters such as the Irish Sea and the North Sea. Given that marine clams in the North Atlantic have always been a common ingredient in clam chowder, many people in the world may have unwittingly eaten these hundreds-year-old clams.

Clam chowder | Jen / Wikimedia Commons

Scientists have conducted a series of studies on why arctic clams live so long. Some people think that the reason is that their oxygen consumption is very low and their metabolism is very slow, so they have the super ability of "frozen age"; others have suggested that the extremely high protein stability and the specificity of cell renewal rate may also be the secret to its longevity.

Today, scientists are still looking for clues in Ming's growth wheel, trying to crack the "secrets" of these long-lived creatures against aging, thus providing inspiration for research related to prolonging human lifespan.

A record book of the marine environment

The scientific value of Ming is more than that. In 2006, when the net was cast over the sea, scientists were looking forward to using these clams to detect changes in the marine environment over the past millennia.

As mentioned above, arctic clams can easily grow to 100 years old, and their growth rings are like a miniature record, integrating signals such as water temperature and food over time, so they can be used to deduce climate and environmental changes during their growth. For example, by detecting various oxygen isotopes in the rings, scientists can determine the temperature of the sea water at the time of shell formation. Therefore, a clam is a record book of the marine environment.

These arctic round clam shells will serve as a reference for us to speculate about the ancient climate. | Hannes Grobe/AWI / Wikimedia Commons

An analysis of Ming and other clams in the sample shows that changes in the atmospheric environment have been driving changes in sea temperature and ocean currents since the beginning of the Industrial Revolution. these important findings will help us better understand the follow-up effects of human-induced climate change. "there are many ways to chart changes in the terrestrial climate, but in the ocean, the data we can get is very limited. Arctic round clam has its own longevity property, which can effectively help us fill this gap and provide us with very accurate marine climate change data. " Researchers once said in an interview.

The arctic round clam in the museum, the life span of this clam is probably more than 100 years old. | Jennifer Boyer / Wikimedia Commons

Although Ming's life came to an abrupt end because of a scientific study, its appearance reminds the world that there are still many mysteries hidden in the ocean that human beings have not yet discovered.