The Polar Retrospective looks at recent scientific publications from the world’s polar regions. This week, we look at studies on bananas, whale-ship collisions, and an important Atlantic ocean stream that may soon slow down. We also note that in Sweden polar research will be strengthened.
Moving forward, the Polar Retrospective will be a collaborative effort by the Polar Journal team. Each writer chooses a scientific topic they found interesting in the past week. The intitials at the end of each section indicate the author. We hope you enjoy it.
Melting Arctic slows important Atlantic stream
The question had been asked for a while. Could the Atlantic Meridional Overturning Circulation (AMOC), responsible for our temperate European climate, slow down or even stop? If observations showed a persistent weakening, climate models did not reproduce the observed slow down. A situation that could change thanks to two researchers from UNSW Sydney’s new modelling.
According to the results of their study published on November 18 in Nature Geoscience, the supply of meltwater from the Greenland ice cap and Canadian glaciers could well constitute the missing piece of a puzzle showing a rather dark picture. Simulations by UNSW researchers show that, if colossal quantities of meltwater are taken into account in climate models, the AMOC becomes a third weaker at 2°C of global warming, leading to climate disruption much earlier than previously estimated.
The study also shows that the North and South Atlantic Oceans are much more connected than previously thought. And the changes reverberate quickly: it takes no more than two decades for changes in the North Atlantic to be felt in the South Atlantic, with consequences in both hemispheres. M.B.
Is there a cure for banana trees lying dormant on King George’s Island?
The Cavendish banana is Ecuador’s golden goose. Its cultivation floods 25% of the world market, generating 3 billion dollars in 2019, but projections show that a deadly fungus for banana plants, Fusarium oxysporum f. sp. Cubense (FOC), is also gaining “market share”. By 2040, 17% of the world’s crops are expected to be under its control.
Last September, Ecuadorian researchers, including biologist Jeffrey David Vargas Perez from the Escuela Superior Politécnica del Litoral in Guayaquil, showed that 41% of the 77 microbial strains collected in Antarctica for the study slowed the growth of the fungus.
Isolated near the Escudero station and near Great Wall, two bacteria belong to the Streptomyces genus and particularly affect the metabolism of FOC. The one at Great Wall shares 97% of the genome of Streptomyces fildesensis, a symbiotic bacterium of the Chinese black ant, which acts as a shield against fungal diseases, but has no anti-FOC effect.
In Ecuador, 30% of plantations are owned by 5,000 small companies. The FOC filaments penetrate the roots of their hosts and colonise their xylem, their epidermis…
To prevent this, farmers treat them with phytosanitary products, temporarily change crops or use GMOs. Juan José Pons, coordinator of the Ecuadorian banana cluster, told Food Tank in 2021 that “this has a major economic impact, because they have to use more resources than they had planned to make an extra effort against this plague”. The samples taken by the Ecuadorian mission 24 and the Chilean mission 56 offer a glimmer of hope for banana farming. The active substance has yet to be discovered. C.L
New research center to strengthen polar research in Sweden
On November 6, the Swedish Center for the Arctic and Antarctic was officially established in Kiruna. It is a collaboration between Luleå University of Technology, Umeå University and the Swedish Polar Research Secretariat. The aim of the center is to improve the national and international coordination of Swedish research and education on the polar regions.
The focus is on the polar regions, particularly the Arctic, as climate change is occurring up to four times faster here than the global average. Melting ice and thawing permafrost have far-reaching effects on ecosystems and habitats — far beyond the polar regions. At the same time, geopolitical pressure is being intensified by the increasing demand for raw materials and military developments, for example following Russia’s invasion of Ukraine.
The center combines the strengths of the partner institutions: While the universities contribute their expertise in research and teaching, the Swedish Polar Research Secretariat provides the infrastructure, such as the icebreaker Oden and the Abisko Scientific Research Station.
This collaboration creates synergies that not only address current challenges such as the green transition and security in the Arctic, but also support long-term projects such as the Swedish chairmanship of the Arctic Council (2027-29) and the International Polar Year (2032-33). With the annual “Forum for the Arctic and Antarctic”, the center also creates a platform for dialogue with stakeholders and public involvement — an important bridge between science and society. J.H.
Large whales at risk of ship collision in 92 percent of their habitats
A study published in the scientific journal Science layed out the habitats of four large whale species: humpback whales, blue whales, sperm whales, and fin whales. It compared these maps with the global distribution of shipping traffic and arrived at a regrettable conclusion: In 92 percent of their habitats whales risk colliding with ships.
According to the study, since commercial whaling has almost disappeared, ship collisions now pose the biggest threat to whales. Unfortunately, not much is done to prevent this. In fact, protections to prevent collisions are present in fewer than 10 percent of “whale movement hotspots”.
On a positive note, it seems that whales are relatively safe in the world’s Polar regions. At least the study concludes that the Arctic Ocean contained only 0.5 percent of collision hotspots while the Southern Ocean contained none at all. This is a result of low ship traffic in these regions, in spite of high whale presence. O.E.
Link to the study: Anna C. Nisi et al. ,Ship collision risk threatens whales across the world’s oceans. Science386,870-875(2024). DOI:10.1126/science.adp1950
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