The team also analyzed thorium isotopes in ocean sediments to separate cosmic dust from terrestrial dust and infer past ice conditions.

Researchers distinguished cosmic dust from terrestrial material by measuring helium-3 in sediment layers, enabling them to identify periods of year-round versus seasonal sea-ice cover.

Two competing explanations for Arctic nutrient dynamics were discussed: increased productivity from more photosynthesis during lower ice is favored over nutrient dilution from ice melt, suggesting higher marine productivity under reduced ice.

The study suggests future Arctic ice loss could boost nutrient uptake by surface organisms, potentially affecting the Arctic food web and fisheries and carrying implications for ecological and geopolitical dynamics.

Nutrient cycling analyses, including foraminifera shell records, indicate phytoplankton drawdown of nutrients peaks when sea ice is low and wanes as ice builds up.

Overall, the link between ice coverage and nutrient dynamics implies shifts in Arctic food webs as melt progresses.

Findings indicate the central Arctic was perennial ice-covered during the last glaciation, with a transition to seasonal ice in the warm early Holocene and a subsequent increase in ice cover later.

As sea ice declined at the end of the last ice age, cosmic dust deposition rose, signaling more open water, with similar patterns observed during the late 20th-century retreat.

Three sediment sites across a gradient of modern ice cover show that year-round ice corresponds to less cosmic dust, while open-water periods allow more dust to settle.

Space-dust data provide a valuable new tool for studying the Arctic Ocean, a region less understood than areas accessible by satellites.

A new study in Science reconstructs 30,000 years of central Arctic sea-ice coverage by analyzing dust deposition in Arctic sediment cores, showing that ice presence correlates with reduced dust accumulation.