Mysterious Black Eggs Found Hidden In Ocean Depths

By Brian Myers | Published

Researchers in Japan recently revealed an unusual haul from one of the darkest depths of the sea. Black eggs, reported to be laid from flatworms, were taken from the Kuril-Kumchatka Trench in the northwest Pacific Ocean. The eggs and the creatures that lay them are some of the many mysterious forms of marine life that have evolved to exist at depths that exceed 20,000 feet under the sea.

Credit: The Royal Society Publishing

The skilled research team pulled the black eggs from the murky depths and employed remote-controlled retrieval vehicles. At astounding depths, they discovered the eggs attached to pieces of rock, successfully removed them, and scooped them away. Hokkaido University researcher Keiichi Kakui wasn’t at all sure about what the team had discovered but was shocked to learn what these jet-black eggs contained.

The black eggs contained an impressive amount of flatworm embryos.

A DNA analysis of the black eggs soon gave researchers an unexpected discovery. Inside the small capsules were flatworm embryos in varying stages of development. Surprisingly, this was the first time these eggs were found at this depth, shattering the 17,000 depth in which they were previously discovered to survive.

While the discovery of the black eggs did indeed surprise the Japanese researchers, it shouldn’t be too much of a shock when scientists discover a species living in parts previously unknown.

Upon carefully cutting the eggs open, a milky white fluid oozed from the inside. Each egg contained multiple flatworm embryos, ranging from three to seven for each dissected specimen. A fairly impressive amount, considering the black eggs only measured about a tenth of an inch in diameter.

A marine flatworm

What’s even more shocking is what the DNA analysis further revealed. These flatworms are close cousins to the ones that we find every day on the surface of the Earth. Scientists believe that the flatworms that live in shallow water may have, over time, moved into deeper waters, eventually paving the way for the species that researchers retrieved from incredible depths.

Researchers found the black eggs thousands of feet below what they thought was the flatworm’s limit.

The mysteries of the deepest parts of the oceans are slowly being solved, though scientists will admit that what is currently known is a far cry from understanding everything in the abyss. While the discovery of the black eggs surprised the Japanese researchers, it shouldn’t be too much of a shock when scientists discover a species living in previously unknown parts.

Another marine flatworm species

It’s a widely held belief by marine scientists that there could be as many as two million different species of life in the salty waters that cover most of the Earth’s surface. Currently, science has only identified roughly 250,000 of them. The identification of the flatworms and their black eggs aside shows just how much there is to learn about the ocean’s depths.

The newly identified species from the deepest parts of the ocean aren’t limited to small flatworm eggs, tiny crustaceans, and various amoeba. Giant squids were once believed to be seafarer fiction until these giant sea monsters were caught. In 2021, Japanese scientists successfully identified a 55-pound slickhead fish that had previously been undiscovered. The large fish was aptly named “Yokozuna,” after the top rank in Sumo wrestling.

Source: Royal Society Biology Letters