Arctic kelp is absorbing toxic metals from melting glaciers

The Arctic is changing fast. Ancient ice is melting, glaciers are shrinking, and seasons are shifting. Below the surface, vast kelp forests sway along rocky coasts, hidden from sight.

These marine giants are more than plants. They are the architects of entire ecosystems, offering shelter, food, and stability to countless marine species. But as the Arctic transforms, so its kelp forests change too.

A recent study shows that melting glaciers and permafrost are changing kelp ecosystems by increasing freshwater run-off. The research was conducted by scientists from EU projects FACE-IT, ECOTIP, and SEA-Quester.

What the experts found is both startling and deeply revealing: shifts in water chemistry, microbial communities in flux, and an unexpected entanglement with heavy metals.

The story of Arctic kelp is not just an ecological tale – it is an economic and social one, reaching far beyond the cold northern seas.

A warming Arctic, a changing coastline

The Arctic is heating up – faster than anywhere else on the planet. This isn’t a slow, creeping shift; it’s a rapid and relentless transformation.

With glaciers melting and permafrost thawing, vast amounts of freshwater are flooding into coastal seas. It’s a deluge that doesn’t just mix and disappear. The chemistry of the water shifts, salinity drops and light struggles to penetrate as suspended sediments cloud the once-clear depths.

For kelp, these changes aren’t trivial. They depend on stable conditions that include sunlight, salt, and predictable nutrient flows.

But with sediments thickening the water, photosynthesis becomes a challenge. Light barely reaches their fronds, stalling their growth. And the run-off doesn’t just bring fresh water; it carries something far more sinister – metals, both essential and toxic.

Heavy metals in the water

What happens when kelp absorbs the very waters that nourish them? The answer lies in their elemental makeup.

The research team studied kelps from various locations – some in areas with heavy runoff and others in clearer waters. Their findings were striking. Kelps from high-run-off areas contained significantly elevated levels of metals like cadmium, lead, and mercury.

Mercury in these kelps was 72% higher than in cleaner areas. That’s a serious warning. Kelp supports Arctic marine life, but when it absorbs metals, the pollution spreads through the ecosystem.

Small marine creatures graze on kelp, larger predators consume them, and over time, toxic elements creep their way up the food chain. Eventually, they land on the plates of Arctic communities that rely on seafood.

What begins in a hidden kelp forest could have consequences that reach dinner tables far from the icy shores.

Microbial world living on kelp

A blade of kelp is covered in bacteria, fungi, and other life forms. These microbes play many important roles. They shape kelp health, aid in nutrient cycling, and offer a first line of defense against pathogens. But just like the kelp itself, they are sensitive to change.

The researchers found that run-off is rewriting the microbial landscape. The balance of bacteria living on kelp is shifting, and with it, the very functions that keep these marine plants thriving.

Some microbes that help break down organic matter are disappearing, while metal-tolerant ones are growing. This shift could disrupt kelp, the animals that rely on it, and the entire marine ecosystem.

Potential of Arctic kelp cultivation

But there’s another side to this story. While heavy metal accumulation spells trouble for marine life, it also points to an unexpected opportunity. Kelp is a natural sponge, pulling metals from the water with remarkable efficiency. Could this ability be harnessed?

Scientists are looking into something called phytomining – using plants and algae to pull valuable metals from the environment. Arctic waters hold rare earth metals, crucial for tech like wind turbines. Could kelp be the answer? Maybe.

If managed correctly, kelp cultivation could offer a sustainable way to harvest these elements, reducing reliance on traditional mining, which scars landscapes and pollutes ecosystems.

At the same time, kelp could serve as a living sensor, a way to track pollution levels in Arctic waters. By monitoring changes in its elemental composition, researchers might be able to map contamination hotspots and predict where environmental threats are most severe.

The future of Arctic kelp

The future of Arctic kelp remains uncertain. With the Arctic warming, run-off levels will only increase.

The delicate balance that has sustained these underwater forests for millennia is shifting in ways scientists are only beginning to grasp.

Will kelp adapt, or will these forests shrink, taking with them the biodiversity they support?

One thing is clear: kelp is at a crossroads. It is both a victim and a potential solution – threatened by climate change yet offering a key to understanding and mitigating its impacts.

The study is published in the journal Scientific Reports.

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