The Ice Age woolly rhinoceros may have owed much of its evolutionary success not to the frozen Siberian landscapes with which it is most closely associated, but to the more temperate regions of Eurasia, a sweeping new analysis of ancient DNA and Pleistocene habitats suggests. The findings highlight the importance of studying ancient DNA from southern regions, where genetic diversity may have originated and persisted but has been overlooked because DNA preservation is generally better in northern Eurasia. The woolly rhinoceros was one of the Ice Age’s iconic species, inhabiting Eurasia for more than 100,000 years until its extinction near the beginning of the Holocene. Despite surviving the glacial and interglacial climate cycles that characterized the Pleistocene for thousands of years, it’s still relatively unknown how these drastic environmental changes shaped the animal’s evolution, population, and eventual decline. Ancient genomic studies have revealed previously unknown genetic diversity, but greatly limited genomic records – exclusively from the Late Pleistocene Northeastern Siberia – leave major gaps in the understanding of the species’ population structure, migration, and genetic history across much of their range, particularly in mid-latitude Eurasia. Xiao-Le Lei and colleagues address these gaps by screening 183 woolly rhinoceros fossils from across Eurasia and recovering 29 mitochondrial genomes and 14 nuclear genomes from specimens spanning East Asia, the Altai region, and Europe, and combined these data with previously published genomes from woolly rhinoceroses and related species. Using several complementary dating methods, Lei et al. placed the fossils across multiple stages of the Ice Age, extending back more than 200,000 years. The authors also modeled woolly rhinoceros habitat across the past 500,000 years using fossil records and climate data on Pleistocene temperature, rainfall, and food availability to evaluate how long-term environmental shifts affected changes in the rhinoceros’s population history and genetic structure. The findings show that woolly rhinoceros populations had a complex genetic history shaped by climate and shifting habitats. Mitochondrial evidence shows that major maternal lineages emerged roughly 460,000 years ago, with a clear genetic divide between East and West Eurasia and the greatest diversity concentrated in mid-latitude regions rather than Siberia. Moreover, the genetic data suggest that the rhinoceros’s greatest genetic diversity arose in mid-latitude East Asia, rather than high-latitude Siberia, while the Altai region served as a long-term refugium and dispersal hub during interglacial periods. The findings also revealed evidence of gene flow between woolly and Merck’s rhinoceros, indicating that the two species interbred during the Late Pleistocene.

 

This summary was updated at 15:30 US ET on Tuesday, 09/08/26

Rivers may be delivering far more microplastic pollution to the oceans than previously realized, with developing countries accounting for nearly all of the global flow, according to a new study. The worldwide analysis also finds that heavy rainfall can unleash surges of microplastics into rivers – a climate-sensitive pollution threat that could intensify as extreme weather becomes more common. Microplastics have become a pervasive and long-lasting form of pollution, with recognized threats to ecosystems, water quality, and human health. Each year, tens of millions of metric tons of microplastics enter the environment, and much of that material ultimately reaches the oceans. Rivers are a major pathway for transporting these particles from inland regions to coastal waters. However, estimates of global riverine microplastic pollution vary widely because of inconsistent sampling methods and limited understanding of how rainfall and runoff affect their transport. Here, Hehao Qin and colleagues developed a new framework to produce more reliable, high-resolution estimates of microplastic concentrations and export from rivers. According to the authors, their approach harmonizes differences in particle size and sampling methods, while using machine learning to account for both human activity and natural processes. It also tracks how rainfall can either increase or dilute microplastic concentrations. Using this approach, Qin et al. estimate that rivers worldwide delivered roughly 263,000 tons of microplastics to the ocean in 2022, with 96% originating from the Global South – Southeast and East Asia alone contribute to more than half of this total. Plastic use, poorly managed waste, and human development were the strongest drivers of geographic differences in microplastic concentrations, while weather and seasonal conditions influenced short-term fluctuations. The findings show that extreme rainfall events can substantially increase the movement of microplastics into rivers, particularly in regions with high plastic use and poor waste management. Qin et al. warn that climate change could worsen this problem as extreme rainfall becomes more frequent and intense, potentially creating short-lived but highly concentrated pollution pulses into rivers and marine environments.

Extreme heat has become more common—both research and lived experience document this—but when it arrives is a different question. A new study finds that rather than occurring only during warm seasons, extreme heat events have become more frequent in the months before and after, too.

Applied Microbiology International (AMI) has responded to the European Commission’s consultation on the proposed EU Ocean Act, highlighting the essential contribution of marine microorganisms to ocean health, climate regulation, biodiversity and the blue bioeconomy.

Peking University, Sep 28, 2026: The woolly rhinoceros was one of the most iconic cold-adapted animals of the Pleistocene. Yet its genetic origins, population history, and responses to repeated glacial–interglacial cycles have remained poorly understood.