Holocene paleohydrological reconstruction and carbon accumulation of a permafrost peatland using testate amoeba and macrofossil analyses, Kuujjuarapik, subarctic Québec, Canada

Testate amoeba analyses were realized to reconstruct Holocene hydroclimatic variations and carbon accumulation from two peat cores collected in a permafrost peatland located at the southern limit of the discontinuous permafrost zone near Kuujjuarapik, subarctic Québec, Canada (55°13′N, 77°41′W). Results from the central core show synchronic changes with lake level variations from northeastern Québec. Palsa aggradation has been identified from 660 to 140 cal. BP with changes in testate amoeba assemblages, reconstructed surface dryness and strongly decomposed peat. Our results also show that low carbon accumulation rates (9.5 g·m− 2·yr− 1 and 8.6 g·m− 2·yr− 1) are linked to colder periods that may be associated with solar minima (AD 1460–1550 and AD 1645–1715). Recent warming of the last decades shows an important return to peat accumulation following permafrost degradation in the region.

► Palsa aggradation identified between 660 and 140 cal. BP
► Low CAR values (9.5 and 8.6 g C·m− 2·yr− 1) are linked to solar minima.
► Testate amoebae is effective for paleohydrological studies on permafrost peatlands.
► Recent important increase of peat accumulation is linked to recent warming.