15 December 2025: A new study on the Impact of baleen whales on ocean primary production across space and time

A study by Freitas and colleagues, titled “Impact of baleen whales on ocean primary production across space and time”, was published in the journal Proceedings of the National Academy of Sciences (PNAS) in September 2025.

Primary production in the ocean is the process by which phytoplankton use sunlight, CO2, and nutrients to create new organic matter and increase their abundance. This is fundamental to supporting marine food webs and global carbon sequestration, that is, the capture and storage of carbon for the long term. When a whale defecates or dies, the faeces and its corpse sink to the bottom of the ocean, and this way, whales contribute to ocean primary production by releasing nutrients such as nitrogen, phosphorus and iron, yet the extent of their contribution is unclear.

In this study, the authors presented daily estimates of nutrient input by baleen whales in high-altitude feeding grounds (Nordic and Barents Seas), based on the chemical analysis of faeces and urine. They then used ecosystem models to assess the impact of these nutrients on primary production. The models indicated that baleen whales, including minke, fin, humpback, blue and bowhead whales, support annual and seasonal primary production, with varying impacts across space and time.

The study highlights the ecological significance of nutrient cycling by whales (supporting up to 10% of net primary production in offshore areas, during the summer season) and underscores the value of integrating whale nutrient data into ecosystem modelling to assess the broader impacts they have on marine productivity.

You can read the full article by Freitas et al., here: https://doi.org/10.1073/pnas.2505563122

Photo credit: Aqqalu Rosing-Asvid.