It may smell bad, but as it turns we all rely on sulphur far more than we know.

An important building block of life, sulphur is used by our bodies for movement, digestion and for our overall health. The amount of sulphur in your hair determines how curly it is, for example.

And from the surface of Mars to the permafrost slumps of the Beaufort Delta, it is also a valuable tool for scientists asking important questions about our world.

Dr. Julian Morton has been tracking sulphur concentration in prehistoric animal bones dating back to the last ice age and Dr. Simon Bottrell has been using different varieties of the element to track permafrost slump in the Beaufort and Mackenzie Delta areas. Both spoke this summer as part of the Aurora Research Institute's speaker series.

"For many years, sulphur isotopes have been used by archaeological studies to look at food sources for animals and humans," said Morton. "It tells you which part of the Earth's surface animals have been feeding on. It tells us about diets. It tells us about mobility."

During the last ice age, the Beaufort Delta and Mackenzie Valley SA¹ú¼ÊÓ°ÊÓ´«Ã½” and pretty much the entire Arctic SA¹ú¼ÊÓ°ÊÓ´«Ã½” was a very different place. At the extent of the last glacial maximum, when continental ice covered much of the Northern hemisphere, a massive plain connected Canada to Scandinavia across thousands of kilometres. The famous "land bridge" between Alaska and Russia was a mere corner of this massive ecosystem. Known as Beringia, this dusty ancient land mass carved a valley of sorts between massive ice sheets covering much of Siberia and covering the Arctic Ocean.

It was dust then SA¹ú¼ÊÓ°ÊÓ´«Ã½” now it's scientific gold. As everyone knows, dust gets into everything, including the bones of the animals that lived in Beringia at the time. That dust also contains sulphur , which alerted scientists to a rather quick and sudden change to the Arctic ecosystem roughly 15,000 years ago.

Sulphur atoms normally carry 32 neutrons apiece. However, there also exists sulphur atoms that have 34 neutrons SA¹ú¼ÊÓ°ÊÓ´«Ã½” known as isotopes SA¹ú¼ÊÓ°ÊÓ´«Ã½” which makes them heavier. Micro organisms tend to prefer the lighter 32-neutron version and leave the heavier isotopes for the soil to pick up, which then makes it way up the food chain, ultimately ending up in the bones of herbivores that consume plants.

However, around the time of rapid global warming, several Arctic ice age animals, including mammoths, showed a sudden spike of the lighter isotope in their remains. Scientists call this phenomenon the Late Pleniglacial Sulphur Excursion SA¹ú¼ÊÓ°ÊÓ´«Ã½” and it correlates quite well with a temperature spike discovered through ice cores taken in Greenland that show rapid global warming at the same period. Current evidence suggests the climate over Greenland was "reorganized" over the course of three years, resulting in an average temperature increase of 10 C in just a few decades. By comparison, a 2023 study found that in modern times temperatures in Greenland were 2.7 C higher on average between 2001 and 2011 than they were over the last millennium.

Warmer temperatures mean thawing permafrost, which used to extend almost twice as far farther south than it does today. This where Bottrell's research comes in. As it turns out, a similar phenomenon may be happening in today's Arctic as temperatures rise.

By looking at different concentrations of the lighter and heavier sulphur at permafrost slump locations, Bottrell's research shows that where permafrost thaws and the above ground gives way, those areas have extremely high concentrations of the lighter 32 neutron version of sulfur. Soil samples normally show closer to a 50/50 split between the two types of sulphur, and control samples in Bottrell's study reflect this. After the lighter sulphur is exposed, it breaks down and the ratio quickly returns to normal.

In other words, melting permafrost releases lighter sulphur into the ecosystem that is taken up by the food chain and can serve as a signal for rapid ecological shifts like the one currently underway.

So mystery solved? Not quite, note both scientists SA¹ú¼ÊÓ°ÊÓ´«Ã½” there's still sulphur currently unaccounted for.

"It's looking like there are mechanisms by which permafrost degradation can introduce large amounts of substrate sulphur into ecosystems," said Bottrell. "But this can only be part of the story because of the whole of northwestern Europe was under one big freezer. Sulphur has to be coming from elsewhere as well."