Greenland’s landscape is defined by its fjords, which are long, deep, narrow arms of the sea. These inlets are bordered by steep cliffs that plunge into cold waters. Their direct connection to the vast Greenland Ice Sheet makes them particularly noteworthy.
The Glacial Origins of Fjords
Greenland’s fjords were sculpted over millennia by the immense power of glaciers. Vast sheets of ice flowed from the island’s interior, slowly carving deep, U-shaped valleys through the bedrock. As these glaciers advanced, they eroded and deepened the landscape beneath them.
As the global climate warmed and these glaciers began to retreat, the U-shaped valleys they had carved were left exposed. The sea then flooded these depressions, creating the long, narrow inlets observed today. At the mouth of many fjords, a shallower rock barrier, known as a sill, often remains. This sill is a remnant of the glacial moraine, where the glacier deposited sediment before retreating, often making the fjord deeper inland than at its entrance. Greenland’s Scoresby Sund system, one of the world’s largest and deepest fjord systems, serves as an example of this immense scale.
Ecosystems of the Ice-Filled Waters
The marine environment within Greenland’s fjords is characterized by deep, cold waters and the constant presence of icebergs. This unique setting supports a specialized food web, beginning with the introduction of freshwater from melting glaciers. This meltwater carries nutrients from the land into the fjord waters, fueling phytoplankton blooms.
Phytoplankton forms the base of the fjord ecosystem, consumed by zooplankton and krill. These small crustaceans, in turn, become a food source for various fish species, which then support larger marine predators. Seals, such as ringed seals and harp seals, frequently inhabit these waters, along with whale species including narwhals, beluga whales, and humpback whales. The steep, rocky cliffs that line the fjords also provide secure nesting sites for numerous species of seabirds, which forage in the rich, productive waters below.
The Role of Fjords in a Changing Climate
Greenland’s fjords are significant locations for observing the effects of global climate change. Warmer ocean currents are increasingly flowing into these confined waterways, reaching the termini of marine-terminating glaciers. This influx of warmer water causes “submarine melting,” where the glacier ice melts from beneath, significantly accelerating the rate of ice loss.
This interaction between warming ocean waters and the Greenland Ice Sheet within the constricted fjord environments is a primary driver of Greenland’s contribution to global sea-level rise. The retreat of glaciers in these fjords has led to Greenland’s ice sheet losing over 5,100 billion tons of ice in the past two decades. The Ilulissat Icefjord, fed by the fast-moving Sermeq Kujalleq glacier, stands as a key example of these amplified processes. This glacier is a major contributor to rising sea levels.