In 2019, paleontologist Karma Nanglu from Harvard University received a finger-sized fossil. The specimen had originated from a fossil-rich stratum of Cambrian limestone in western Utah, and had been kept in a drawer at a Salt Lake City museum for years.

Upon hearing that there could be a very old tunicate, Nanglu expressed excitement interlaced with caution: "That's a group for which there is essentially no fossil record for the entire 500 million years of recorded history."

For more than two years, researchers on board the French expedition ship Tara sailed through the Pacific, stopping at almost 100 coral reefs to take thousands of water and coral samples. The expedition ended in 2018, and the analysis of the massive amount of data collected has taken five years.

Now, the initial results of the data analysis have been published. The findings should help us to better understand the living conditions of corals, to check their health status and to open up new possibilities for nature conservation. 

Ocean deoxygenation has detrimental repercussions. Fish, crabs and other significant species of marine life that are unable to flee these low oxygen zones may perish as a result. People who depend on them for food and employment may be subsequently impacted by their absence as many of these species are economically significant.

Additionally, there is a negative feedback loop at play: as ocean oxygen levels decline, so does its capacity to absorb carbon dioxide. This may cause global warming to accelerate even further.

According to the WMO projections, there is a 90 percent chance that the El Niño event will persist over the second half of 2023. It is predicted to be at least moderately strong.

El Niño episodes typically last between nine and twelve months and occur every two to seven years on average. It is a naturally occurring climate pattern linked to the warming of the tropical Pacific Ocean's central and eastern ocean surface temperatures.