Dissolved organic matter dynamics in a whale-dominated coastal system: Insights from Península Valdés, Argentina

Research at Península Valdés, Argentina, reveals that large marine mammals, particularly whales, significantly influence dissolved organic matter (DOM) dynamics in coastal ecosystems. The study found that the carbon isotopic signal of dissolved organic carbon (DOC) was predominantly derived from whale and phytoplankton sources, suggesting a 'whale pump' mechanism where whales contribute both labile and recalcitrant DOC to coastal habitats. Microbial overconsumption during the whale calving season increased the DOC:DON ratio, indicating higher refractoriness of DOC. Bioavailable DOC ranged from 18.6% to 52.7% of the total DOC pool, while recalcitrant DOC concentrations averaged 200 ± 19 μM in non-whale seasons and 180 ± 7 μM during whale seasons. These findings underscore the role of whales as vectors for DOM, modulating its dynamics and potentially impacting coastal ecosystem health.

Egea, L. G., Jiménez-Ramos, R., D’Agostino, V. C., Degrati, M., Giacomino, S., Kim, G., Han, H., & Loizaga, R. (2026). Dissolved organic matter dynamics in a whale-dominated coastal system: Insights from Península Valdés, Argentina. Marine Environmental Research, 214, 107778. https://doi.org/10.1016/j.marenvres.2025.107778