Is Greenland's melting ice creating an unexpected CO2 sponge?

In the remote, icy realm of Bowdoin Fjord in northwestern Greenland, researchers have been unraveling the complex interplay between glacial meltwater and the fjord's carbonate chemistry.

As glaciers melt, they release freshwater into the fjord, diluting the salinity and altering the concentrations of dissolved inorganic carbon (DIC) and total alkalinity (TA).

Their work can be found here:
Effects of the glacial meltwater supply on carbonate chemistry in Bowdoin Fjord, Northwestern Greenland

https://doi.org/10.3389/fmars.2022.873860

This influx of meltwater lowers the partial pressure of CO2 (pCO2) in the fjord's surface waters, transforming them into a sink for atmospheric CO2.

However, the story is not quite so straightforward. The meltwater also carries land-derived substances that add complexity to the carbon dynamics in the fjord.

Near the calving front of the glacier, where the influence of meltwater is strongest, the decomposition of organic matter counteracts the CO2 sink effect, elevating pCO2 levels. Additionally, the dissolution of carbonates and silicates from the meltwater impacts the DIC and TA concentrations in the fjord.

To investigate these intricate processes, the researchers employed a range of analytical techniques, including coulometry and titration for precise measurements of DIC and TA, as well as stable oxygen isotope ratios (d18O) and chlorophyll a concentrations.

Notably, some of the data was collected using a state-of-the-art carbon analyzer from UIC Inc., capable of measuring total inorganic carbon (TIC), total organic carbon (TOC), dissolved inorganic carbon (DIC), and total carbon (TC).

As the Arctic faces the challenges of a changing climate, with glaciers retreating and meltwater input increasing, understanding the carbon dynamics in coastal fjords like Bowdoin becomes increasingly important.

This study sheds light on the complex interactions between freshwater, land-derived materials, and the marine environment, providing insights that could help predict how fjords will respond to future changes and influence the global carbon cycle.