Recent trends and biases in mesophotic ecosystem research

Mesophotic ecosystems (~30-150 m) represent a significant proportion of the world’s oceans, yet have long remained understudied due to challenges in accessing these deeper depths. Due to advances in underwater technologies and a growing scientific and management interest, there has been a major expansion in research of both (sub)tropical mesophotic coral ecosystems (MCEs) and temperate mesophotic ecosystems (TMEs). Here, we characterize the recent global trends in mesophotic research through an updated release of the “mesophotic.org” database where we reviewed and cataloged 1,500 scientific publications. In doing so, we shed light on four major research biases: a gross imbalance in (a) the geographic spread of research efforts, differences in (b) the focal depth range and (c) research fields associated with study organisms and research platforms, and (d) the lack of temporal studies. Overall, we are optimistic about the future of mesophotic research and hope that by highlighting current trends and imbalances, we can raise awareness and stimulate discussion on the future directions of this emerging field.

Methods
The mesophotic.org online data repository is open access and available on the “Publications” page with advanced search capabilities and the ability to download a csv file (www.mesophotic.org/publications). A static copy of the database used in the analyses (publications through 2023, inclusive) is archived here.