Sedimentary ancient DNA record in the Labrador Sea
Today, sea ice cover is rapidly declining in the Arctic Ocean and major changes in the Arctic marine ecosystems are starting to appear. The full implications of a changing Arctic ecosystem are not well understood as past time series documenting marine communities and biodiversity across rapid climate events are scarce and incomplete. Here we show, using sedimentary ancient DNA metabarcoding to document eukaryotic communities, that higher diversity is recorded in a warmer, sea ice free Labrador Sea compared to when this region is sea ice covered. Changes in diversity and communities happen slower than the rapid climate warming of Greenland Interstadial 8 (ca. 38,000 years ago) and the Bølling period (ca. 14,700 years ago). Instead, surface ocean conditions exert control on the ecosystem, and diversity changes are linked to (sub-)surface warming, a retreating or changing sea ice cover and freshening of the surface via meltwater pulses. Our observations from the paleoclimate record suggest that when sea ice is further decreasing under global warming, the (sub-)polar marine ecosystems will change drastically, and feedbacks to the carbon cycle and climate system become very likely.
Today, sea ice cover is rapidly declining in the Arctic Ocean and major changes in the Arctic marine ecosystems are starting to appear. The full implications of a changing Arctic ecosystem are not well understood as past time series documenting marine communities and biodiversity across rapid climate events are scarce and incomplete. Here we show, using sedimentary ancient DNA metabarcoding to document eukaryotic communities, that higher diversity is recorded in a warmer, sea ice free Labrador Sea compared to when this region is sea ice covered. Changes in diversity and communities happen slower than the rapid climate warming of Greenland Interstadial 8 (ca. 38,000 years ago) and the Bølling period (ca. 14,700 years ago). Instead, surface ocean conditions exert control on the ecosystem, and diversity changes are linked to (sub-)surface warming, a retreating or changing sea ice cover and freshening of the surface via meltwater pulses. Our observations from the paleoclimate record suggest that when sea ice is further decreasing under global warming, the (sub-)polar marine ecosystems will change drastically, and feedbacks to the carbon cycle and climate system become very likely.
University of Geneva