As global climate change intensifies, ocean acidification is becoming a ‘relentless killer’ threatening coral reef ecosystems. Recently, a research paper published in the international authoritative journal Research has revealed diverse survival strategies of reef-building corals in response to ocean acidification, providing a new perspective for understanding and protecting this fragile marine ecosystem.

New Arizona State University-led research findings from studying over two decades of satellite observations reveal that the Earth’s continents have experienced unprecedented freshwater loss since 2002, driven by climate change, unsustainable groundwater use and extreme droughts. The study highlights the emergence of four continental-scale “mega-drying” regions, all located in the northern hemisphere, and warns of severe consequences for water security, agriculture, sea level rise, and global stability. The research team reports that drying areas on land are expanding at a rate roughly twice the size of California every year. And, the rate at which dry areas are getting drier now outpaces the rate at which wet areas are getting wetter, reversing long-standing hydrological patterns. The negative implications of this for available freshwater are staggering. 75% of the world’s population lives in 101 countries that have been losing freshwater for the past 22 years.

A new study offers the first direct evidence that deep-dwelling mesopelagic fish, which account for up to 94 percent of global fish biomass, excrete carbonate minerals at rates comparable to shallow-water species. The findings validate previous global models suggesting that marine fish are major contributors to biogenic carbonate production in the ocean.

Researchers from Prof. Quan-You Liu's team at Peking University decoded the complex accumulation mechanisms of China’s nonmarine shale oil, overcoming challenges from extreme geological heterogeneity. Through analysis of the Bohai Bay Basin, the research team revealed that the synergistic coupling of multiple geological factors governs shale oil accumulation and established multi-scale, multi-factor accumulation models for non-marine shale oil. Their new predictive model pinpoints high-yield "sweet spots," validated by drilling success, offering a roadmap for efficient exploration and extraction of nonmarine shale oil.

Nearly 14,000 volunteers took part in the citizen science project Iguanas from Above, helping to count endangered Galapagos marine iguanas through an online survey – and in doing so, contributed to the preservation of this unique lizard species. Every aerial image of the iguana colonies captured by drones was reviewed by at least 20 independent participants—a total of over 1.3 million inputs— explains campaign leader Dr Amy MacLeod from Leipzig University’s Institute of Biology. She concludes that citizen scientists can be deployed effectively to analyse drone data sets and estimate population sizes, thereby allowing researchers to obtain critical information on these marine iguanas more rapidly. MacLeod and her team have just published a paper on the project in the journal Nature Scientific Reports.

In two separate studies leveraging satellite imagery and artificial intelligence techniques, researchers reveal patterns of industrial fishing in coastal marine protected areas (MPAs) worldwide. Collectively, the findings, which may seem contradictory, show that although industrial fishing vessels are present in many protected areas worldwide, MPAs with the highest levels of protection remain largely unfished. Both studies suggest that proper investment in protected areas will pay off and that synthetic aperture radar (SAR) satellite technology could be one of the key tools used to safeguard the ocean’s future sustainability. Roughly 8% of the global ocean is formally protected, with ambitious international targets aiming to more than triple that coverage by 2030. While such protections can yield substantial long-term benefits, especially when paired with adequate fisheries management, potential gains are often compromised by inadequate regulations. In many cases, destructive, illegal, or unreported fishing practices persist even within designated protected areas due to insufficient safeguards. Global-scale monitoring of industrial fishing, including within MPAs, has been aided by the emergence of automatic identification system (AIS) data, which tracks the activity of individual vessels. However, not all vessels are required to use it. Many disable their transponders to avoid detection, making it difficult to obtain reliable, large-scale estimates of fishing pressure within MPAs. As a result, the true effectiveness of MPAs worldwide remains poorly understood.

In one study, Jennifer Raynor and colleagues analyzed 455 coastal MPAs classified as “fully” or “highly” protected under the MPA guide, an assessment framework that evaluates protections based on both regulations and management practices. These categories fully ban industrial fishing within their bounds. Raynor et al. combined AI methods with a recently published global SAR satellite imagery dataset to directly identify industrial fishing vessels operating within MPAs, regardless of whether their AIS is active. The authors found that, overall, very little unauthorized industrial fishing activity occurs in MPAs that prohibit it, averaging just one vessel detected per 20,000 square kilometers – a rate 9 times lower than in unprotected exclusive economic zones. Although a few MPAs in East and South Asia showed higher vessel densities, these cases were outliers driven by small geographic areas and sporadic detections. Only seven MPAs worldwide had vessels present on more than half of observed days, highlighting how rare such activity is in strongly protected areas. Raynor et al. also demonstrate SAR imagery’s reliability in detecting unauthorized fishing vessels. Not only did the method successfully identify AIS-broadcasting vessels with high accuracy, it also detected vessels in 163 MPAs where AIS data showed none, particularly in regions like Southeast Asia, where AIS is often incomplete.

In another study, Raphael Seguin and colleagues quantified fishing activities across a larger group of 6021 coastal MPAs representing a wide range of protective categories as outlined by the International Union for Conservation of Nature (IUCN) management framework. Using the same SAR dataset and deep learning models, Sequin et al. discovered that nearly half of the MPAs evaluated showed evidence of industrial fishing at levels in many cases matching or exceeding those in nearby unprotected waters. According to the findings, industrial fishing vessels were detected in 47% of the world’s coastal MPAs. While stricter IUCN categories did correlate with reduced fishing, the authors concluded that factors such as MPA size and remoteness were more predictive of fishing presence than official protection category alone. In a Perspective, Boris Worm discusses the possible drivers underlying the differences in the two studies’ findings. “Many MPAs have been established quickly without strong protective regulations, meaningful consultation with local stakeholders, or appropriate management capacity. In some cases, this has resulted in “paper parks” that are recognized as protected areas but do not prevent harmful activities,” writes Worm. “Yet the available data show that where proper investments are made, industrial exploitation is curtailed, and protective measures are comprehensive, long-term benefits will accrue.”

Data is available for the production of data visualizations. For more information, please contact Raphael Seguin at raphaelseguin@protonmail.com

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.