Fur seals on a distant island chain are exposed to high levels of poisonous heavy metals, but they remain healthy.

Juan Fernández fur seals are so ineffectively comprehended that they were thought of as terminated for almost 100 years before a remainder populace that had figured out how to sidestep the ages of trackers was rediscovered during the 1960s.

Their isolation on a named archipelago 600 kilometers off the Chilean coast is largely responsible for their mysterious nature. These far-flung islands are in a protected national park, the last place you’d think animals would be exposed to high pollution levels. However, the samples I collected and analyzed with coworkers reveal something else.

Our latest review, distributed in Illustrious Society Open Science, dissected fur seal crap and found groupings of cadmium and mercury that were among the most noteworthy revealed for any warm-blooded creature around the world. This species is ingesting uncommonly high concentrations of these harmful, weighty metals through its eating regimen, yet the way that they enter the established pecking order ended up being more muddled than we expected.

By concentrating on these warm-blooded marine creatures, researchers can find out how contaminated the more extensive climate is. Even better, we might pick up a few tips from them about how to survive in the face of pollution.

Where are the heavy metals coming from?
We are encouraged to consume zinc and iron, two metals that are essential micronutrients. With mercury and cadmium, this is not the case. Distraught Hatter’s illness is a neurological problem related to mercury inebriation, while itai sickness, which deciphers from the Japanese as “it harms it harms,” is a condition causing extreme bone torment and debilitatingness that came about because of persistent cadmium harming that impacted individuals working in sullied rice fields in Toyama prefecture, Japan. Even in low concentrations, these heavy metals are extremely hazardous and have few known biological applications.

Mercury is used by miners to extract gold from ore. Credit: Senderistas/Shutterstock

Heavy metals are naturally present in the crust of the earth and are produced by volcanic eruptions or the weathering of rocks. They’re likewise created during mining, waste burning, and steelmaking. We were initially perplexed by these fur seals’ apparent toxic diet because the Juan Fernández Islands are so far from any major industries.

But the archipelago is on the edge of the South Pacific subtropical gyre, a rotating current that has collected a huge amount of plastic from the ocean. The plastic patch is thought to be larger than India.

Sadly, Juan Fernández fur seal mothers must traverse significant distances through this plastic cloud in order to hunt the nutrient-rich prey they require to continue their pregnancies and produce sufficient fatty milk for their pups. There is evidence that plastic debris can absorb toxins like cadmium. So, did the fur seals ingest plastic by accident or eat animals that had? The response was more muddled.

Algae, or phytoplankton, are microscopic organisms similar to land plants in that they produce food from sunlight and contain chlorophyll. Algae metabolism relies on micronutrients like zinc, but gyres and other parts of the ocean typically have low concentrations. Phytoplankton in these regions have evolved to use cadmium instead, according to studies; this is the one and only biological process where cadmium can be used.

Minuscule, tiny creatures called zooplankton eat the cadmium-sullied green growth, which is then eaten by fish and bigger creatures, which at last end up in the guts of octopus and squid, which are among the fur seal’s number one foods. These mollusks can aggregate huge amounts of weighty metals in their kidneys and, particularly, in an organ known as the hepatopancreas. Fur seals consume the entire prey, including the organs that are rich in heavy metals, in contrast to humans, who typically only consume the tentacles. Therefore, it’s possible that phytoplankton’s evolutionary adaptation has increased the likelihood that animals further up the food chain will be exposed to cadmium.

The South Pacific gyre is a major global source of small pieces of plastic. Credit: Eriksen et al. (2014)/PLOS One

A new mystery
Since cadmium seriously harms the skeletons of warm-blooded animals, including people, we needed to see, in the wake of finding such huge amounts of cadmium in fur seal crap, whether this weighty metal was being assimilated into their bones.

The cadmium content of the Juan Fernández fur seal skeletons was to be expected. Be that as it may, shockingly, we were unable to find whatever other mineral changes would be normal in a creature experiencing cadmium harm. This suggests that this species has adapted in some way to resist the harmful heavy metal.

If that is the case, it may suggest that Juan Fernández fur seals have been exposed to cadmium-rich natural sources for thousands of years. To comprehend how, we must distinguish between natural and manufactured sources.

If you do this, you might get a great reward. There is certain to be a lot to gain from the strength of this puzzling species, which defeated termination regardless and figures out how to flourish in reality as we know it, where contamination has overflowed even the most remote corners.

More information: Constanza Toro-Valdivieso et al, Heavy metal contamination in pristine environments: lessons from the Juan Fernandez fur seal ( Arctocephalus philippii philippii ), Royal Society Open Science (2023). DOI: 10.1098/rsos.221237

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