Salmon becoming river ‘ghosts’ due to deadly droughts and violent floods
Peer-Reviewed Publication
This June, we’re turning our attention to the ocean in honor of World Ocean Day on June 8. Covering more than 70% of our planet, the ocean is full of discovery, wonder, and life. Join us as we explore the science behind marine ecosystems and the important role oceans play in shaping our world.
Updates every hour. Last Updated: 28-Jun-2026 15:15 ET (28-Jun-2026 19:15 GMT/UTC)
Most of the microlitter present in the South Atlantic Ocean originates from the West African coast and is particularly concentrated in areas near the equator and off the coast of Brazil. This is demonstrated by a study conducted by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB), Spain, which has successfully identified in detail the main geographical sources of these microparticles, their large-scale distribution, and the processes that drive their accumulation in the ocean.
The solid oxide fuel cell (SOFC) power system fueled by NH3 is considered one of the most promising solutions for achieving ship decarbonization and carbon neutrality. This paper addresses the technical challenges faced by NH3 fuel SOFC ship power system, including slow hydrogen (H2) production, low efficiency, and limited space. It introduces an innovative a NH3-integrated reactor for rapid H2 production, establishes a safe and efficient all-electric SOFC all-electric propulsion system adaptable to various sailing conditions. The system is validated using a 2 kW prototype experimental rig. Results show that the SOFC system, designed for a target ship, has a rated power of 96 kW and an electrical efficiency of 60.13%, meeting the requirements for rated cruising conditions. Under identical catalytic scenarios, the designed reactor, with highly efficient heat transfer, measuring 1.1 m in length, can achieve complete NH3 decomposition within 2.94 s, representing a 35% reduction in cracking time and a 42% decrease in required cabin space. During high-load voyage conditions, adjusting the circulation ratio (CR) and ammonia-oxygen ratio (A/O) improves system efficiency across a wide operational range. Among these adjustments, altering the A/O ratio proves to be the most efficient strategy. Under this configuration, the system achieves an efficiency of 55.02% at low load and 61.73% at high load, allowing operation across a power range of 20% to 110%. Experimental results indicate that the error for NH3 cracking H2 is less than 3% within the range of 570–700 °C, which is relevant to typical ship operation scenarios. At 656 °C, the NH3 cracking H2 rate reaches 100%. Under these conditions, the SOFC produces 2.045 kW of power with an efficiency of approximately 58.66%. The noise level detected is 58.6 dB, while the concentrations of CO2, NO, and SO2 in the flue gas approach zero. These findings support the transition of the shipping industry to green, clean systems, contributing significantly to future reductions in ocean carbon emissions.
28 April 2026 / Kiel. How much of the essential trace element iron remains available for marine life in the ocean depends critically on the diversity of organic molecules in seawater. This is shown by new research published in Nature Communications by an international team led by Dr Martha Gledhill from the GEOMAR Helmholtz Centre for Ocean Research Kiel. The study demonstrates for the first time that the formation of iron minerals and the distribution of dissolved and particulate iron in the South Pacific can be realistically predicted when the chemical complexity of organic matter is taken into account. These findings provide an important basis for understanding how marine life may respond to a warmer and more acidic future ocean.
A new decades-long study of oceanographic data provides the first evidence that deep-ocean heat has moved closer to Antarctica, threatening the fragile ice shelves that fringe the continent.
Biodegradable plastics hold potential for reducing marine plastic pollution, but degrade too quickly, limiting their practical use. Researchers from Gunma University now show that crab shell by-products can reduce the breakdown rate of biodegradable plastics in seawater by altering the microbial communities that colonize their surfaces, known as the plastisphere. These findings could help design plastics that stay durable during use and then degrade at an appropriate time once in the ocean.
The top ocean predators during the Cretaceous were primarily giant marine reptiles and sharks, or so researchers have thought. Now, a new study suggests colossal “kraken-like” octopuses once hunted Late Cretaceous seas, growing as large as 19 meters in length and competing with – and perhaps even preying upon – large ocean apex predators like mosasaurs. For hundreds of millions of years, marine ecosystems were thought to be dominated by large vertebrate apex predators. Invertebrates served as smaller prey. However, unlike shelled invertebrates, octopuses followed a unique evolutionary trajectory. Instead of protective shells, these creatures evolved soft-bodies, which gave them unprecedented mobility, vision, and intelligence. Some of these species grew to enormous sizes, too, and have functioned as top-tier predators, yet their precise ecological role has remained uncertain due to limited fossil evidence.
To aim to fill this gap, Shin Ikegami and colleagues evaluated the patterns of wear on fossilized jaws of ancient octopus relatives. Wear on the jaw – produced when biting into hard, skeletal prey – leaves characteristic damage similar to the damage seen in modern shell-crushing cephalopods. Measurements of an octopus jaw can also be used to estimate their overall body size. Ikegami et al. reexamined 15 large fossil jaws from ancient octopus relatives and identified clear signs of wear on particularly well-preserved specimens. Using advanced digital fossil-mining techniques, they uncovered 12 additional jaws of finned octopuses from Late Cretaceous sediments (~100 to 72 million years ago). In analyzing them, they identified two main species – Nanaimoteuthis jeletzkyi and N. haggarti. These finned octopuses, N. haggarti in particular, grew to exceptional sizes, say the authors, ranging from ~7 to 19 meters, rivaling the size of contemporaneous giant marine reptiles and potentially representing the largest invertebrates currently described. Moreover, in the largest individuals, the jaws showed extensive wear, with once-sharp features in small juveniles becoming blunted and rounded over time. The wear patterns suggest that these creatures were active carnivores that routinely crushed hard shells and bones with powerful bites, and used their long, flexible arms to seize sizable prey while dismantling it with their strong beaks, a behavior that has been linked to advanced intelligence. According to Ikegami et al., the findings indicate that N. jeletzkyi and N. haggarti were not merely prey but highly active participants in shaping marine ecosystems while occupying roles previously attributed only to large vertebrates.