To improve our understanding and guide future studies and applications, we review the biogeochemistry of the rare earth elements (REE). The REEs, which form a chemically uniform group due to their nearly identical physicochemical properties, include the lanthanide series elements plus scandium (Sc) and yttrium (Y). These elements, in conjunction with the neodymium isotopes, are powerful tools for understanding key oceanic, terrestrial, biological and even anthropogenic processes. Furthermore, their unique properties render them essential for various technological processes and products. Here, we delve into the characteristics of REE biogeochemistry and discuss normalization procedures and REE anomalies. We also examine the aqueous speciation of REEs, contributing to a better understanding of their behavior in aquatic settings, including the role of neodymium isotopes. We then focus on their environmental distribution, fractionation, and controlling processes in different environmental systems across the land‐ocean continuum. In addition, we analyze sinks, sources, and the mobility of REEs, providing insights into their behavior in these environments. We further investigate the sources of anthropogenic REEs and their bioavailability, bioaccumulation, and transfer along food webs. We also explore the potential effects of climate change on the cycling, mobility and bioavailability of REEs, underlining the importance of current research in this evolving field. In summary, we provide a comprehensive review of REE behavior in the environment, from their properties and roles to their distribution and anthropogenic impacts, offering valuable insights and pinpointing key knowledge gaps.

The extents of volcanic island shelves result from surf erosion, which enlarges them, and volcanic progradation, which reduces them. However, mass‐wasting, tectonics and sediment deposition also contribute to their morphology. In order to assess the relative significance of these various processes, we have mapped in detail Faial Island's shelf in the Azores archipelago based on interpretation of geophysical and geological data. The nearshore substrates of the island, down to 30–50 m depth, are rocky and covered by volcaniclastic boulder deposits formed by surf action on now‐submerged lava flows. Below those depths, sandy and gravel volcaniclastic beds dominate, building clinoforms up to the shelf edge. In some sectors of the coast, prograding lava has narrowed the shelf, but, in contrast to nearby Pico Island, we find fewer submarine‐emplaced lavas on the shelf. In this island, we interpret the distance between the coastline and the shelf edge as almost entirely a result of a straightforward competition between surf erosion and lava progradation, in which erosion dominates. Therefore shelf width can be used as a proxy for coastline age as well as for wave energy exposure. The stratigraphy of shelf deposits in boomer seismic data is examined in detail to assess the roles of different sediment sources, accommodation space and wave exposure in creating these deposits. We also show evidence of mass‐wasting at the shelf edge and discuss the possible origins of slope instability. Finally, we discuss the contributing role of tectonics for the development of the shelf.