Science & Tech · Science & Environment · 6 hrs ago
Ancient fish ear stones reveal how Arctic cod survived the Ice Age
Researchers used ancient fish ear stones to trace Arctic cod through tens of thousands of years.
The stones came from seafloor mud collected at five sites near the North Pole and north of Greenland.
Of 256 stones recovered, 79 were dated, with the oldest remains nearly 48,000 years old.
Both ice cod and polar cod lived near the pole during milder periods, when thinner ice and incoming ocean water may have helped support food.
The record near the pole has a long gap from about 35,000 to 12,000 years ago, which includes the coldest part of the Ice Age.
Researchers think food shortages likely explain the gap, as thick summer ice and reduced water flows could have limited the food web.
Ice cod also survived farther south during the harshest cold, but warming may put these cold-adapted fish at risk.
Ear stones from the Arctic seafloor show that ice cod and polar cod lived near the North Pole during milder periods of the last ice age.
Ice cod also survived farther south during the coldest period, according to the findings described in the article.
Researchers say the fish remains suggest a food web existed beneath Arctic ice.
The traits that helped the fish endure extreme cold may make them vulnerable as the ocean warms.
- Who
- Researchers led by Pauline Snoeijs-Leijonmalm of Stockholm University.
- What
- Ancient fish ear stones indicate that Arctic cod survived parts of the last ice age.
- When
- The remains date back nearly 48,000 years; researchers recovered them in 2021.
- Where
- Five sites near the North Pole and north of Greenland.
- Why
- The ear stones help show where the fish lived and suggest food was available beneath the ice.
This story does not have two clearly opposing sides.
An expedition aboard the Swedish icebreaker Oden recovered a fish otolith in mud samples from the Arctic seafloor.
Ear stones indicate that both cod species lived near the North Pole during milder periods.
Researchers found no ear stones from this period at their two sites near the pole.
The coldest part of the ice age fell within the period with no ear stones found near the pole.
- Ear stones recovered
- 256 from five sites
- Ear stones dated
- 79
- Oldest remains
- Nearly 48,000 years old
- Near-pole cod species
- Ice cod and polar cod
- Sea-level drop
- More than 330 feet (100 meters) during the coldest part of the ice age
What people are saying
But when the first bottom samples arrived on deck, we immediately noticed a fish otolith.