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Marine scientists discover remarkable importance of seagrass in preventing heavy metal contamination: 'It's an environment we cannot lose'

"As long as the seagrasses are there, the metals are safe and trapped in the sediments."

"As long as the seagrasses are there, the metals are safe and trapped in the sediments."

Photo Credit: iStock

Scientists in Australia have discovered that seagrass is stashing away thousands of tons of heavy metals, protecting people in the local community — for now.

Hakai Magazine reported that an operation of an ore smelter in Port Pirie, South Australia, over more than a century has led to dangerous heavy metal pollution in the air, on playground surfaces, in children's blood, and in the local mangroves' mud.

While mapping a submarine deposit of heavy metals like zinc, cadmium, and lead, marine ecologist Anna Lafratta and her colleagues made a surprising discovery: Seagrass within a 42-square-mile area off of Port Pirie has trapped thousands of tons of these heavy metals in its soil since smelting began.

This has protected local residents from increased exposure to these contaminants. For instance, even low levels of lead in the blood of children can lead to behavior and learning problems, lower IQ, hyperactivity, slowed growth, hearing problems, and anemia, according to the U.S. Environmental Protection Agency. 

Unfortunately, Port Pirie's seagrass is susceptible to the consequences of an overheating planet, such as rising sea levels, storm surges, and hotter temperatures. If the seagrass were to die or diminish, it would release those contaminants back into the sea.

"It's an environment we cannot lose," Lafratta told Hakai. "As long as the seagrasses are there, the metals are safe and trapped in the sediments."

In addition its heavy metal trapping capabilities, seagrass is also a carbon-capturing superstar, helping us in our fight against rising global temperatures. In fact, experts estimate that seagrass provides roughly $88.3 billion worth of carbon storage services every year, according to Phys.org. 

Plus, seagrass is an important habitat and food source for a number of organisms like fish and juvenile crustaceans. In fact, a sudden resurgence in seagrass off of south Florida has helped support endangered manatees who rely on this vegetation for food. Seagrass meadows also oxygenate water and help recycle nutrients.

Though it may be difficult for local conservationists to stave off climate-related threats to Port Pirie's seagrass, Alice Jones, a marine ecologist at the University of Adelaide, told Hakai that minimizing damage from things like dredging, trawling, and the runoff of excess nutrients from land will help.

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