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In order to understand what defense mechanisms corals have formed against warm waters, Meibom and his colleagues wanted to understand how much heat the corals and their complex networks (called “full life cycles”) can withstand. He likened it to testing the strength of a rubber band: how far can you stretch it before it breaks? How long does it take to return to normal shape?
Karine Kleinhaus, who studies corals at Stony Brook University, said that understanding how these corals work at the cellular level is crucial. She said: “These amazing corals will be the last corals to survive by the end of the 21st century.” “We need to figure out what they are doing, what is going on, and how they are doing it.”
In their experiments, the researchers grew to Pichia In a series of aquariums, they called it the “Red Sea Simulator”. Each aquarium can be customized to replicate specific water quality conditions and expose corals, algae and bacteria to different temperatures for different periods of time. Then, the researchers examined the genes that corals express in their normal state, how they change when the temperature rises, and how quickly the gene’s activity returns to normal when the temperature drops.
They found that when the water warms, all three organisms can change the genes they use.Taking coral as an example, it discovered the use of genes involved in unfolding protein responses. This mechanism can be used to detect environmental stress and Maintain homeostasis In other studies in the cell, it has been described as coral First line of defense heat proof. At the same time, the algae rejected the activation of genes related to photosynthesis. In general, Red Sea species can survive until the temperature rises above 5 degrees Celsius. Once the scientists lowered the temperature in the tank, even after a week in hot conditions, the entire atoll fish returned to normal. . Meibom compares his adaptability to a super bodybuilder, who can quickly regain his strength after a big exercise and is ready to face another challenge.
Andréa Grottoli, a professor at Ohio State University’s School of Earth Sciences, said: “This paper is really good work, clarifying the early stages of heat-resistant corals’ response to thermal stress.” She studies corals and climate. Variety. However, she noted that this method has some limitations. Just because the genes are activated does not mean that the coral will eventually produce new proteins, which indicates that the coral is responding to the environment, but this is not the whole story. You can think about it. Know exactly which biochemical changes it is adapting to, and how these changes physically alter the coral.
Grottoli also pointed out that the longest exposure time (up to 7 days) in this study was shorter than many real-life heat waves. She said: “Most natural bleaching events last two months.”
Meibom agrees that his research does not explain how these newly activated genes help corals survive, but he said identifying them is a step towards figuring this out. “It provides hints for what is happening.”
It is not clear why these corals have such heat resistance, while other corals do not. Probably not because they evolved in the hot climate of the Red Sea, but because they arrived from a hotter place. Meibom theory suggests that this may be related to species that lived in the Red Sea during the last ice age about 20,000 years ago. The water around the equator evaporates and eventually forms a large glacier. As all the water was trapped in ice, the sea level dropped sharply, isolating the Red Sea from the Arabian Sea, essentially turning it into a lake. The water level drops and salt accumulates, making it a desolate environment. But when the glaciers melted and restored the connection with the rest of the ocean, new water and life forms flooded. These include corals that live in the Arabian Sea, which gradually rise from the warmer southern waters. Only these high-temperature-adapted species are healthy enough to transport their larvae north to the Gulf of Aqaba. “They were selected. It’s like a filter.” Meibom said.
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