A new study in Proceedings of the Royal Society B reveals the surprising neurological landscape of fish brains. Harvard researchers map the internal structures of ray-finned fishes brains in 3D detail, discovering brain size and shape, as well as the endocasts, vary far more than expected.

For 350 million years, ammonites were the resilient masterpieces of the ancient seas. They survived the Great Dying of the Permian-Triassic, an event that wiped out 96% of marine life, only to vanish during the end-Cretaceous extinction that claimed the dinosaurs. Meanwhile, their less-diverse cousins, the nautiloids, sailed through the catastrophe and still inhabit our oceans today.

Why did the invincible ammonites fail while the nautiloids endured?

A recent study published in National Science Review has revealed new insights into the global riverine carbon cycle. This study constructed global maps of riverine dissolved organic carbon (DOC) concentration, along with its radiocarbon (Δ¹⁴C) and stable carbon isotope (δ¹³C) signatures, based on a comprehensive global database and machine learning approaches. It systematically elucidates the sources, spatial distribution, and age characteristics of riverine DOC, quantifies the contributions of different endmembers, and reveals how its age and origin are dynamically regulated by climate conditions, hydrological processes, and soil properties. The results show that soil carbon residence time plays a key role in determining the age of dissolved organic matter transported by global rivers. In particular, warming-induced permafrost thaw is accelerating the release of long-preserved “old carbon” into river systems. Once mobilized, this aged carbon can be transported downstream and participate in aquatic biogeochemical processes, potentially enhancing carbon cycle feedbacks to the climate system.