oceanography

Most research has studied marine heatwaves at the sea surface. Now, a study published in Nature Climate Change analyses the effects of these phenomena at depths of up to 2,000 metres. The research, based on data from waves occurring between 1993 and 2019, shows that these waves tend to be more intense between 50 and 200 metres, and that their duration increases up to twice as much with depth compared to the surface, which has an impact on the marine fauna living in that area.

The Atlantic Meridional Circulation (AMOC), a large system of ocean currents that transports warm water from the tropics to the North Atlantic, could collapse around the year 2050 with serious consequences for the climate, according to estimates by researchers at the University of Copenhagen (Denmark). The IPCC considered a complete collapse unlikely during the 21st century. The results are published in the journal Nature Communications and the authors do not rule out that this collapse may be partial.

This week, Japan began testing a new facility designed to discharge treated wastewater from the Fukushima Daiichi nuclear power plant into the Pacific. The water has been used to cool the melted reactor. After filling more than 1,000 tanks, the storage should reach full capacity early next year.

The deadline passed and after two marathon nights of meetings, the delegations of the UN member states have managed to reach an agreement to make the so-called Oceans Treaty - or BBNJ Treaty, Biodiversity Beyond National Jurisdiction - a reality. New York City has seen the fifth session of this conference bear fruit with an agreement on the wording of the text, seventeen years after the talks began and with negotiations stalled last August due to a lack of agreement. The Treaty aims to protect and regulate the use of areas beyond national jurisdiction, which account for more than 60% of the oceans, or almost half of the planet. Marine genetic resources and how to share these benefits has been one of the main stumbling blocks.

A study published in PLOS ONE reveals that more than 2,600 bacteria live on average on each floating microfibre in the Mediterranean Sea, belonging to 195 bacterial species. This waste from plastic pollution, textiles and fishing activities, once colonised, smells like food and is consumed by marine animals. Among them, pathogenic Vibrio species have been found, a bacterium that can be a threat to bathing and seafood consumption.

The so-called Oceans Treaty, promoted by the UN, has had to be stopped, not concluded, due to the impossibility of reaching an agreement. After a process of more than 16 years, only half a session separates us from the word failure. Let us hope that the resumption of the last session, possibly in the spring of 2023, will offer us the agreement we all wish for.

According to a study off the coasts of France, Italy, Spain, Croatia, Slovenia and Greece, catches of threatened elasmobranchs are higher in partially protected areas than in unprotected areas, suggesting that small-scale fishing may be affecting these species.