Kaffeklubben

The islet is a narrow strip of land about 700 m long ; the maximum height is about 30 m above sea level ^[1] . Until 1996, Kaffeklubben was considered the northernmost land of the Earth (since 1996, the island of ATOW1996 is considered the northernmost territory); located 707 km from the North Pole .

The island has the same name freshwater lake, which is the northernmost lake (and freshwater body in general) on Earth ^[2] . It was formed about 3.5 thousand years ago, when the retreating glacier formed the relief of the plain coast of Greenland. The lake is small ^{[approx. 1]} , its depth is about 14 m ^{[3] [2]} .

The island was first seen by the famous polar explorer Robert Peary in 1900 ^{[4] [5]} . The first landing on the island was recorded in 1921, when the Danish explorer Lauge Koch managed to land on this patch of land ^[6] ; he named it after the cafe in the ^{[approx. 2]} Copenhagen.

Despite the harsh climate, not only bryophytes ( mosses , liverworts ) and lichens grow on the island, but also at least two species of flowering plants - polar poppy and saxifrage superfine ^{[7] [8] [9]} .

In the freshwater lake on the island are microscopic algae - diatoms . A study ^[3] by Bianca Perrin and her colleagues at the University of Franche-Comté in Besançon (France) investigated bottom sediments. It was found that diatoms inhabited the lake almost from the time of its formation about 3.5 thousand years ago. With the onset of a new period of cooling, their population gradually decreased, and about 2.4 thousand years ago, being unable to survive in the absence of sunlight under a thick layer of ice, they completely disappeared from the lake. As a result of climate warming ^[2] , which has been occurring approximately since the beginning of the 20th century, the ice cover of the lake has become thinner, and by the 1960s diatoms reappeared in the lake. At the time of the study, there were already more than 20 species of unicellular algae in the reservoir. ^[ten]