Bauer et al. (2026): In-situ deep ocean monitoring reveals rapid kelp degradation limits marine biomass-based carbon sequestration potential and alters benthic ecosystems
Kohen W. Bauer, Paulo V. F. Correa, Alex Lupin, Stefanie Mellon, Mojtaba Fakhraee, Anna C. Savage, Alison K. Tune, Alexander L. Slonimer, Bradley Rochlin & Fabio C. De Leo, IN: Communications Earth & Environment, https://doi.org/10.1038/s43247-026-03342-0
Sinking macroalgal biomass carbon to the deep seafloor has been proposed as a means of removing atmospheric carbon dioxide, but the persistence of this carbon and its ecological impacts remain poorly constrained. Here, the authors present results from a year-long in-situ experiment in the Northeast Pacific oxygen minimum zone, where kelp was deployed and monitored with high-resolution time-lapse imaging. Over 90% of the biomass decomposed and disappeared within approximately 100 days, primarily via microbial and faunal activity. Some fraction of the carbon likely entered dissolved pools with longer residence times, but overall carbon sequestration efficiency may be limited under these conditions. Kelp emplacement also altered benthic community structure, based on >5000 annotated faunal observations from video imagery spanning 13 species, underscoring important ecological trade-offs.