Ocean Love Story Series | Ashi's Old Grave Together: Childhood sweethearts, living together till death

01

Holding hands with you, growing old together

A and his wife were buried together. Image source: NOAA

This is the A's Xie Lao Tong Xue, a type of sponge.

But after coming to land from the depths of the ocean, they became a symbol of undying love.

The term “grow old together” comes from the line “Hold your hand and grow old with you” in Beifeng (Beifeng) Jigu (Jigu) of the Book of Songs, and “be buried together” comes from another line “Grow in different rooms but be buried together after death” in Wangfeng (Wangfeng) Dache (Dache) of the Book of Songs.

The combination of "growing old together and being buried together" means sharing life and death and being loyal until death.

A creature with such a name is naturally inseparable from marriage and love.

In Japan, being buried together until old age is old is also included in the wedding gifts, implying that the newlyweds will be able to stay together for a long time.

In Europe, Aralia's tomb also has a name related to love, called Venus's Flower Basket. Venus is the goddess of love in ancient Roman mythology.

The specimen of the old couple buried together is exhibited in the museum. Photo by: урьева Светлана (zooclub.ru)

But why does a sponge have such a romantic name and why does it become a symbol of love?

Why does being buried together until old age symbolize love?

A's sponge is a sponge belonging to the class Hexaplocephala and the genus A's sponge.

It originated 540 million years ago and is distributed between 40 and 5,000 meters in the ocean [1], but usually lives in the deep sea below 500 meters below sea level.

This sponge has very beautiful silica spicules that look as crystal clear as glass, so it is also called glass sponge.

These glass-like skeletons help sponges defend themselves against most predators.

And even if they die, the glass structure will remain the same.

Silica bone needles (Image source: Wikimedia)

Although it looks like a glass handicraft, it is an animal after all. They usually attach to the seabed and feed on plankton that filters out seawater.

The seawater flowing through the A's Cave not only carries food, but may also carry the eggs and larvae of some small animals.

For example, a small shrimp called Lixia might have been brought to the tomb of Ashi.

For Lixia, living together with Mr. Ah is a very good skyscraper.

When the shrimps are small, they can enter and exit these sponges freely. As long as they hide inside these sponges, predators outside will have no way to deal with these "glass buildings".

As the shrimps grow larger, one day they will be trapped inside the sponge and will never be able to get out.

Fortunately, the shrimps trapped in the A's cave are usually a pair of male and female. In other words, although they have lost their freedom and are trapped in the cave, this does not affect their reproduction.

The fertilized eggs they produce can still pass through the gaps in the glass building to find a new home, a new "glass building."

It can be said that the two girls trapped in the "Ashi's Tongxuen" are childhood sweethearts who will never leave each other for life. Moreover, there is absolutely no possibility of divorce or regret, which is also the origin of the romantic name "Tongxuen" (Xiu Lao Tongxu).

Of course, you can also think that Lixia in "Growing Old Together in the Same Tomb" is literally living in a "marriage cage."

02

It's not a cage, it's a luxury villa

Shrimp (Photo source: wikimedia)

Li Xia is trapped in a sponge, which makes her sound helpless.

Wouldn't it be better if the shrimps could freely search for food in the sea? After all, if they were trapped in a sponge, there would be less food to eat, right?

Not necessarily. In 2021, an article was published in the online version of Nature, which pointed out that the body structure of the Aristolochia acupuncture point has a very peculiar fluid dynamic effect [2].

When seawater flows through these sponges, it will form a slow current under the influence of the sponge's special structure and will not cause too much impact on the sponge.

At the same time, tiny vortices are generated inside the sponge, which can better keep the food around it. In this way, the sponge can eat the food better.

More importantly, scientists speculate that Astropoda may need to reproduce sexually, and such water flow can also increase the chance of sperm and egg meeting, which is beneficial to their reproduction.

Although the structure of the sponge is to help itself survive and reproduce better, the shrimps living in it also benefit from it and can get more delicious food.

In addition, the "glass frame exterior wall" of the A's tomb can always protect itself from attacks by predators. With food and shelter, the shrimps are reluctant to come out.

03

Natural Engineer

The structure of the Ashi tomb has also given scientists and engineers a lot of inspiration.

Glass sponges like this one have intrigued materials scientists.

Sponges are able to extract silica from seawater to create their own fine glass fiber skeletons, which is valuable for making extremely thin optical fibers.

Scientists are also designing and manufacturing optical fibers by imitating the structure of sponges.

In addition, the special structure of sponge fibers is also very strong. This structure is evolved by sponges to cope with the huge pressure on the seabed.

From the perspective of engineers, this type of structure is also very meaningful because its strength far exceeds that of steel structures used in engineering applications[1] and has the potential to be used in future building designs.

In fact, Norman Robert Foster referenced the structure of the Archibald when designing 30 St Mary Axe in London[3].

However, the shape of this building does not look like a tomb, but rather like a pickled cucumber, so it is also nicknamed the "Sour Cucumber" Building.

"Pickled Cucumber" Building (Photo source: Wikimedia)

Perhaps more buildings will use similar structures in the future.

In this case, the Ashi's tomb together is not only a symbol of love, but its skeletal structure will also actually protect our safety.

The first episode of Ocean Love Story is a romantic love story.

The protagonist of the next episode is not so romantic, even a little weird. See you in the next episode.

References:

[1] Fernandes, Matheus C.; Aizenberg, Joanna; Weaver, James C.; Bertoldi, Katia (21 September 2020). "Mechanically robust lattices inspired by deep-sea glass sponges". Nature Materials. 20 (2): 237–241.

[2] https://www.nature.com/articles/s41586-021-03658-1.epdf?sharing_token=Na7pEFAnL3zP4Qx7 FPiR5dRgN0jAjWel9jnR3ZoTv0MHnjYmodntkPLJm8OrbxC1xrhX87z-TOck7_9y39IvGTY99hc5M70JTycHwYR hJ-b7fUDuSL47j43unCr-nvOF3SqQ7XvXIypTe3uI5fLgyxfW11jAHQc5-DluFrkeBPhTTU-Yz1-mc5Wb_ujiS NHDELBUoIV3DRVDo13yRshzEd1Mbt2qi4FxG4svnoxTcl0%3D&tracking_referrer=www.sciencenews.org

[3] Rao, Rajshekhar (2014). "Biomimicry in Architecture". International Journal of Advanced Research in Civil, Structural, Environmental and Infrastructure Engineering and Developing. 1: 101–107 – via ISRJournals and Publications.

Produced by | Science Popularization China

Author｜Science Scraps

Review | Zhang Wei, Associate Professor of Marine Biology, Shandong University

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