The global marine heatwaves (MHWs) of 2023 were unprecedented in their intensity, persistence, and scale, according to a new study. The findings provide insights into the region-specific drivers of these events, linking them to broader changes in the planet’s climate system. They may also portend an emerging climate tipping point. Marine heatwaves (MHWs) are intense and prolonged episodes of unusually warm ocean temperatures. These events pose severe threats to marine ecosystems, often resulting in widespread coral bleaching and mass mortality events. They also carry serious economic consequences by disrupting fisheries and aquaculture. It’s widely understood that human-driven climate change is driving a rapid increase in the frequency and intensity of MHWs. In 2023, regions across the globe, including the North Atlantic, Tropical Pacific, South Pacific, and North Pacific, experienced extreme MHWs. However, the causes underlying the onset, persistence, and intensification of widespread MHWs remain poorly understood.

 

To better understand the MHWs of 2023, Tianyun Dong and colleagues conducted a global analysis using combined satellite observations and ocean reanalysis data, including those from the ECCO2 (Estimating the Circulation and Climate of the Ocean-Phase II) high-resolution project. According to the findings, MHWs of 2023 set new records for intensity, duration, and geographic extent, lasting four times the historical average and covering 96% of the global ocean surface. Regionally, the most intense warming occurred in the North Atlantic, Tropical Eastern Pacific, North Pacific, and Southwest Pacific, collectively accounting for 90% of the oceanic heating anomalies. Dong et al. show that the North Atlantic MHW, which began as early as mid-2022, persisted for 525 days, while the Southwest Pacific event broke prior records with its vast spatial extent and prolonged duration. What’s more, in the Tropical Eastern Pacific, temperature anomalies peaked at 1.63 degrees Celsius during the onset of El Niño. Using a mixed-layer heat budget analysis, the authors discovered diverse regional drivers contributing to the formation and persistence of these events, including increased solar radiation due to reduced cloud cover, weakened winds, and ocean current anomalies. According to the authors, the 2023 MHWs may mark a fundamental shift in ocean–atmosphere dynamics, potentially serving as an early warning of an approaching tipping point in Earth’s climate system.

WASHINGTON, D.C. – U.S. Naval Research Laboratory (NRL) has prototyped a Hydrogen Small Unit Power (H-SUP) system to reduce detectability and improve readiness of Marine Corps in expeditionary warfare operations.

Researchers from Japan Agency for Marine-Earth Science and Technology (JAMSTEC) have discovered a deep-sea limpet species 6 km beneath the northwestern Pacific Ocean, the deepest known habitat for any true limpet, naming it after the character “Large Monk” Wadatsumi, from the manga series ONE PIECE.

A first-of-its-kind experiment tracing evolution across 25 generations shows that tiny crustaceans at the heart of the ocean food web rely on a largely unknown biological toolkit to survive the stresses of climate change. The study reveals that it’s not only genetic changes that help these animals adapt to warming and acidifying ocean conditions. In addition, little-known epigenetic changes play a crucial role too. Remarkably, the researchers led by Melissa Pespeni at the University of Vermont discovered that the two mechanisms operate independently offering a two-pronged strategy for resilience. Until now, few studies have tracked genetic and epigenetic changes in tandem over many generations. This experiment is one of the first to do so in a long-term, replicated evolution study—offering some of the strongest evidence yet that epigenetic change can help populations survive and perhaps allow future genetic adaptation. Which means that copepods may be tougher under the stresses of a warming ocean than scientists previously would have predicted. And that could be good news for the fish species who eat copepods as primary prey—and many other creatures.

A study led by Associate Professor Kelton McMahon at University of Rhode Island’s Graduate School of Oceanography has found that food webs on tropical reefs are more fragile than we once thought. Instead of being part of a highly connected system where species can easily switch food sources, many reef creatures in these incredibly biodiverse ecosystems rely on surprisingly narrow, specialized energy pathways that link specific species to distinct sources of primary production.

Ben Kirtman, a renowned atmospheric scientist who raised the bar in the study of climate predictability, has been named the new dean of the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science.

A world-first study led by Museums Victoria Research Institute has revealed that beneath the cold, dark, pressurised world of the deep sea, marine life is far more globally connected than previously imagined. 

Inspired by a hitchhiking fish that uses a specialized suction organ to latch onto other marine animals, MIT engineers designed a mechanical adhesive device that attaches to soft, slippery surfaces and remains there for days or weeks. The device could be used to deliver drugs in the GI tract or monitor aquatic environments.

Biologging is transforming wildlife research, yet stingrays have been overlooked due to their unusual body shapes. For the first time, researchers successfully developed and field-tested a biologging tag for the whitespotted eagle ray. The multi-sensor device stayed attached for up to a record 60 hours, revealing how they feed, move and interact with other species. Virtually impossible to capture before, these insights now shed light into this threatened, understudied species that plays a vital role in marine ecosystems.

Researchers at Institute of Industrial Science, The University of Tokyo, have taken a great stride in supporting earthquake prevention research by developing a system for seafloor position measurements with centimeter-level precision. Combining the Global Navigation Satellite System–Acoustic and an unmanned aerial vehicle, the proposed system eliminates the need for manned surface vessels.