Esther Ray
When asked to picture a reef, most people imagine a colorful array of different corals and anemones, with vibrant fish and other marine life. It is clear that coral reefs play a critical role in forming environments for all types of marine creatures, but corals in the deep sea are often overlooked.
A family of coral known as Stylasteridae (more commonly referred to as lace coral) can be found in shallow and deep water reefs, and have skeletons made up of calcium carbonate: a chemical compound found in rocks as the minerals calcite and aragonite, which are also the main components of eggshells. Stylasteridae are an important part of deep-water coral gardens, as they act as substrate, or an underlining layer of the ecosystem, for fish and other marine life. They are most prevalent and most diverse in the southwest Pacific, but can be found in the Arctic Circle and Antarctic as well. More recently, the species has been identified in areas surrounding Africa, and in 2020, evidence supported the existence of the family in the Red Sea.
A vast amount of the deep sea has remained unexplored for centuries, so many places have been assumed to be uninhabitable due to the extreme conditions that exist within deeper waters. Total darkness, a lack of oxygen and food sources, as well as severe pressure are all aspects of the deep sea that are in conflict with the general requirements of life. The Red Sea in particular, which has water reaching depths of nearly 10,000 feet, has been categorized as having extreme conditions, not only because of the depth, but also because of the abnormally warm temperatures and high salinity. The deeper parts of the Red Sea have gone unexplored for hundreds of years due to this assumption, and that is why the discovery of Stylasteridae in its deeper regions was so surprising.
In September and November of 2020, various explorations of different areas of the Red Sea were conducted by a Saudi Arabian organization, and one was focused on the deep sea. The exploration was conducted using submersibles, which are crafts containing lights, cameras, probes, and more, and are designed to be fully submerged in water without acquiring damage. The submersibles collected fragments of deep water skeletal structures that were later analyzed and processed in labs. Physical examinations of the fragments were used to study their formations along with DNA extractions and found that a genus from the family Stylasteridae, Stylaster, was present in the Red Sea. Not only was this the first time that a deep sea Stylasteridae had been reported there, but the species of Stylaster found was also a completely new one, and it was given the name Stylaster tritoni.
Although the discovery of a new species of stylasterid isn’t the most groundbreaking news, it is a significant step towards the expansion of deep sea exploration, and proves to scientists just how much could be present in deeper waters they might not know about. Not only does the discovery of Stylaster tritoni expand the diversity of the family, it also suggests that there may be undiscovered marine life present in the Red Sea that benefits from these corals. A discovery like this, in an environment that was previously assumed to be difficult for certain species to inhabit, challenges the current knowledge that scientists have surrounding marine life as we know it to be. This begs the question- what else lies in the depths that is waiting to be discovered?
Citation
Maggioni, D., Terraneo, T. I., Chimienti, G., Marchese, F., Pica, D., Purkis, S. J., Benzoni, F., Eweida, A. A., Cairns, S. D., & Rodrigue, M. (2022, March). The first deep-sea stylasterid (Hydrozoa, Stylasteridae) of the Red Sea. ResearchGate. Retrieved September 27, 2022, from https://www.researchgate.net/publication/359486936_The_First_Deep-Sea_Stylasterid_Hydrozoa_Stylasteridae_of_the_Red_Sea