LIVINGSTON ISLAND, Antarctica, Feb 6, 2024 (BSS/AFP) - A gunshot interrupts

the peaceful sleep of a leopard seal, lying nonchalantly on a small piece of
ice floating in the shadow of an Antarctic glacier.

Researcher Diego Mojica lowers his rifle.

The mammal, one of the largest predators on the White Continent after the
orca, flinches from the impact of the remote biopsy -- a small red pipette
that bounces off its skin, taking with it a piece of flesh -- and swims away.

Mojica, a Colombian marine biologist, descends from his boat alongside
Livingston Island, in the South Shetland archipelago, to retrieve his sample.

Excitedly, he explains to an AFP team accompanying him on a day of research
amid the glaciers, how rare it is to get so close to a leopard seal -- a
solitary and usually aggressive species that feeds on penguins.

Mojica is studying the impact of mercury, used in activities such as mining
thousands of kilometers away, on Antarctica's large mammals.

The toxic heavy metal is believed to reach the ocean through rivers or rain,
after it "evaporates into the air," said Mojica, who works for Colombia's
Malpelo Foundation, which specializes in the study of marine fauna.

Scientists at Spain's University of Murcia have previously found mercury in
the feathers of chinstrap penguins on King George Island, the closest point
in Antarctica to the Americas.

The pollution appears to extend south to Livingston Island and the Gerlache
Strait, a natural channel off Antarctica.

The United Nation's Global Mercury Partnership warns that marine mammals,
because they are "at the top of the food chain, are particularly susceptible
to contamination" by the metal.

Later on his voyage -- a Colombian scientific expedition to Antarctica --
Mojica finds himself surrounded by humpback whales.

When a tail or back pokes out of the rough waters, he carefully takes aim
with his rifle.

This time, he retrieves his sample of skin and fat from the freezing waters
using a net.

Humpback whales consume large quantities of krill, small crustaceans
susceptible to mercury contamination.

Mojica will study the samples to determine if "mercury has been transmitted
from one link to the next in the food chain."

According to UN environmental agency UNEP, if an animal consumes mercury, it
may suffer "reproductive failure, behavioral changes and may even (die)."

In 2013, 140 countries signed the Minamata Convention to reduce the use of
mercury, which can cause severe health problems.

Some 9,000 tons of the toxic substance are released into the atmosphere every
year.

Artisanal mining is the main source of mercury emissions, where the element
is used to collect gold by binding to it.

Coal combustion is another major source. But mercury is also present in many
household products like batteries, some lightbulbs and even mascara.

"We want to do our part to be able, as much as possible, to propose credible
measures for the conservation and protection of these emblematic mammals,"
said Mojica.