A recent study conducted by scientists from San José State University and NASA revealed that in certain coastal regions of Greenland, glacial meltwater can promote the growth of phytoplankton, the basis of the marine food chain and a key player in carbon capture.
When a glacier discharges freshwater directly into the sea, it generates upwelling plumes that bring nutrients from deep layers to surface areas.
This process can be particularly beneficial in summer, when surface nutrients are scarce and phytoplankton needs a boost to grow.
An emblematic case: the Sermeq Kujalleq glacier
The scientific team analyzed the Sermeq Kujalleq (Jakobshavn) glacier and its fjord in the Disko Bay, using the ECCO-Darwin oceanic model and satellite data.
The results indicate that in this area, the contribution of meltwater could increase phytoplankton biomass by 15% to 40% during the summer.
Not all glaciers generate the same effect
This phenomenon is not replicated in all glaciers in Greenland. Its impact depends on:
- The shape and depth of the fjord
- Subglacial dynamics
- Connection with deep waters
- Whether the glacier is marine-terminating (direct discharge into the sea)
If the glacier retreats and ends on solid ground, as has already happened in other fjords, subglacial upwelling could disappear, eliminating the nutrient input.
High-resolution models to understand the impact
Researchers used a coupled physical-biogeochemical model, nested within ECCO-Darwin, to compare years with high and low glacial discharge (2008, 2012, 2017, 2019).
Controlled experiments were conducted to assess the impact on:
- Biological productivity
- Atmospheric carbon capture
Phytoplankton and CO₂ capture: limited but relevant benefits
The seasonal growth of phytoplankton leads to a net increase in CO₂ capture of approximately 3% annually in the studied area.
However, this benefit does not fully compensate for the reduced physical absorption of CO₂ caused by the lower water salinity.
Claiming that the effect “counteracts” the impact of melting would be an oversimplification. The balance remains limited and localized.
Climate change and glacial dynamics: a complex interaction
Melting in Greenland continues to intensify due to rising global temperatures.
The team plans to extend their research to other glaciers to assess under what conditions this phenomenon of nourishing upwelling could be repeated.
Conclusion: specific findings in a concerning global context
This discovery provides valuable information on the interaction between glaciers, oceans, and climate change, but it must be interpreted with caution.
The detected benefits are temporary, seasonal, and geographically restricted, and do not offset the global risks of accelerated melting.
