Researchers from Rutgers University–New Brunswick have been studying mercury contamination in penguins on the Antarctic Peninsula to establish a new baseline for mercury levels in this remote area. Driven by parallels to the environmental threats highlighted by Rachel Carson’s “Silent Spring,” the study explores mercury pollution’s impact and distribution among penguins, highlighting the importance of these birds as environmental sentinels.
John Reinfelder, a professor at Rutgers, draws direct comparisons between historical DDT contamination and current mercury pollution. “In the 1960s, we were discovering DDT in remote places where it wasn’t being used,” said Reinfelder. “It’s a similar story today with mercury.” Notably, mercury pollution reaches these isolated regions through long-distance atmospheric transport, with penguins acting as bioindicators.
“With mercury, there’s an analogy to DDT,” Reinfelder mentioned, setting the context for the study published in Science of the Total Environment. The research team, including Reinfelder and Philip Sontag, the lead author, analyzed feathers from three species of penguins—Adelie, gentoo, and chinstrap—collected near Anvers Island during the 2010-11 breeding season. These samples had been delayed due to agricultural safety concerns but were later analyzed to measure mercury levels and isotope ratios.
The study found significant differences in mercury accumulation patterns among the penguin species. “In Adelie and gentoo penguins, mercury levels ‘were some of the lowest for any species of penguin observed to date in the Southern Ocean,'” they noted. Chinstrap penguins displayed “significantly higher” levels, attributed to their migration patterns towards latitudes with higher mercury concentration during the nonbreeding season. This was confirmed by the correlation between foraging location, indicated by carbon-13 levels, and mercury presence in penguin feathers.
Sontag emphasizes the significance of this finding, as it forges a new understanding of how environmental factors such as feeding and migration patterns can affect mercury exposure in marine life. Before this study, there was limited knowledge about the heightened mercury exposure experienced by penguins migrating northward. “These data give us a way to learn not only about mercury accumulation, but about penguin ecology more broadly,” noted Reinfelder.
Efforts to curtail mercury emissions, marked prominently by the Minamata Convention on Mercury, have led to decreased atmospheric levels, mirrored by a study from MIT showing a 10% reduction from 2005 to 2020. However, ongoing mercury emissions, mainly from small-scale gold mining, continue to pose risks. “Are we going to see a decrease in levels in the fish that people and animals eat? That’s the hope,” remarked Reinfelder, drawing lessons from the past to address current environmental challenges.
