Picture (above): Iceberg B-09B (right) collides with the Mertz Glacier tongue in 2010. Credit: NASA Images.

The Southern Ocean is a place where water sinks and recirculates over centuries in the deep ocean. This process is significant for the global ocean circulation and carbon storage. The storage of carbon in the deep ocean is partly a reflection of the biological activity that occurs when the water is at the surface before it sinks. This is why it is important to evaluate how unexpected and dramatic changes at the surface will change biological and chemical cycles, so that we can understand their impact on a larger scale.

In this paper, the researchers investigated how a major glacier tongue break in the Mertz polynya in Antarctica impacted phytoplankton blooms. Larger phytoplankton blooms increase the amount of carbon that can be stored in the deep ocean. The researchers found that after the glacier tongue break:

  • the bloom duration and ice-free period decreased,
  • the start of the bloom and the retreat of sea-ice were delayed,
  • the intensity of the bloom and the sea-ice concentration increased.

These findings show that natural changes can impact the timing of phytoplankton growth that may have consequences for the rest of the ecosystem, from Antarctic krill to baleen whales.

  • Paper: Liniger, G., Strutton, P. G., Lannuzel, D., & Moreau, S. (2020). Calving event led to changes in phytoplankton bloom phenology in the Mertz polynya, Antarctica. Journal of Geophysical Research: Oceans, 125, e2020JC016387. https://doi.org/10.1029/2020JC016387