Wild Cam: ‘Forever Chemicals’ affect rat reproduction

Researcher Emily Choi releases offspring from a cliff on Coats Island. Credit: Douglas Noblet

It hangs from cliffs a few hundred meters above Hudson Bay and offers some great views. The deep blue of the water below contrasts with the white rocks of the exposed cliffs and the emerald hues of the tufts of grass covering the less steep areas. But the real reason Emily Choi spent two months in 2019 on Coates Island in Nunavut, Canada, was to observe a large colony of thick-beaked moors that breed on cliffsides.

Choi, a postdoctoral fellow studying biology at McGill University in Montreal, had to take a rock-climbing course to do her research. But its rewards were perfect sightings of nature, including a pod of about 200 beluga whales (Leagues Delphinaperus) Swimming in the water below. Nearby, about 100 walruses (Odobenus rosmarus) will come out of the water to dry and get some sun, making enough paddle that Choi and her colleagues can hear several hundred meters away.

“It’s a really cool and unique place,” she said.

But egg and blood samples brought in by other researchers in previous years revealed that this ecological landscape in northern Hudson Bay may be polluted by invisible pollution from thousands of miles away. Long-term ‘permanent chemicals’ may affect the mass and reproduction of thick-beaked moors (Urea Lymphia) during their breeding season, they find.

Forever chemicals refer to a larger group of chemicals called per- and polyfluoroalkyl substances (PFAS). Perfluoroalkyl acids (PFAAs) belong to that larger group. These include a wide range of chemicals used in commercial and industrial products – everything from paint on cookware to Scotchgard waterproof spray. The longest PFAS chain tends to be the most stable.

These chemicals are not usually produced as far north, but can reach the ocean from terrestrial water supplies, and eventually travel by currents to remote parts of the Arctic. It can affect a number of animals, as discussed in the latest issue of Wildlife Professional. But this new research examines the effects on the thick-beaked moor.

“We found significant relationships between these pollutants and PFAAs and thyroid hormones,” Choi said.

Various researchers from Environmental Climate Change Canada have monitored the Moors on Coats Island for nearly 40 years. When Choi and her team went there in June 2019, a small Twin Otter plane dropped them off near the beach near the cliffs where seabirds live. She and her colleagues had to climb a steep hill and then lift their equipment to their cabins near the top. They took blood samples from the moors, measured their body condition, weighed, counted eggs, and extracted other data.

In a study recently published in Environmental pollutionChoy and her colleagues examined some of the effects these perfluoroalkyl acids had on Coats murres based on data from 2016 to 2018 — before Choy herself was there.

The team found significant relationships between the level of long-chain PFAAs and thyroid hormones important in reproduction. They found disruptions in triiodothyronine (T3), which play important roles in metabolism, incubation and thermoregulation in seabirds. The T3 hormone, in particular, helps regulate their body heat so they can better incubate their eggs.

The researchers found that inactivating this chemical affected males more than females. This is key because thick-billed moors share incubating duties, dividing their nest hours into shifts of approximately 12 hours. However, Choi noted that because males tend to observe during the day the researchers were outside, their results may be slightly skewed toward males.

They found that birds with higher concentrations of PFAAs in their system also tended to hatch their eggs earlier. This may be due to more interruptions in the nursery of those birds, Choi said, but the exact reasons for this are unclear. The results also showed that birds with longer chain PFAAs had lower body mass.

Choi said previous studies have shown the relationships between PFAAs and reproduction, but this research describes the direct pathway more specifically.

Choi worries that the effects of PFAAs are just one of many problems affecting Arctic seabirds such as the thick-beaked moor, including habitat disturbance from shipping and climate change. When she was roasting by herself on the island, she was studying the effects of heat stress on birds, for example. “These birds are already under pressure in terms of the effects of change in the Arctic,” she said.

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