Hawaii's Epic Lava Leak Could Bring New Life to the Big Island's Waters

At the southern end of Hawaii’s Big Island, I’m standing on a cliff and watching the newest part of the world being made. Half a mile away, a torrent of lava bursts through the basalt of the island’s edge and pours into the turquoise Pacific. The spout of liquid rock has been shooting into the water day and night for weeks, half-shrouded by a thick cloud of smoke and sulfur dioxide. When the lava hits the ocean’s surface, rocks swept up in the flow explode like fireworks, shooting sharp fragments through the air.

The waters of Hawaii are no stranger to volcanic eruptions; they are, after all, how the islands were formed and continue to be reshaped. But this is unique. At the end of December, 22 acres of the island dropped into the sea as lava from Kīlauea, one of the most active volcanoes in the world, surged through the brittle cliffs. The lava flow shifted from dozens of small leaks to one huge lava “fire hose.” Now thousands of gallons flow into one specific part of the ocean every day.

At first glance, the lava hose looks like a static orange-red column extending from the cliff to the sea—steady, stately. But when I peer closer, I can see the lava bubbling and hissing, the air around it writhing in the 2,000-degree heat. It seems like a Biblical torrent of brimstone, designed to wipe out life entirely and begin anew. What, I wondered, could possibly survive this?

The answer, for the most part, is nothing. “In the areas where lava is entering the sea, there is essentially no marine life, as the bottom is being constantly recreated by the new lava rock,” says Steven Dollar, a marine researcher at the University of Hawaii at Manoa. The waters around the flow are so blistering that not even microscopic plankton could survive in them. Furthermore, waters around an eruption can become so choked with pumice and ash that local fish, birds, marine mammals, and plants die.

But in this case, destruction isn’t as disastrous as it seems. In fact, in the right circumstances a massive eruption like this can give ecosystems a big boost. The changing conditions don’t just wreak havoc; they spur new life.

A few years ago, Eric Achterberg led a team of researchers to study the effects of ash fall from Iceland’s notorious Eyjafjallajökull eruption, whose cloud grounded air traffic around Europe for nearly a week in 2010. They found a significant uptick in iron in the Iceland Basin, which, under the right conditions, could have resulted in a major boom in phytoplankton—a critical part of larger ocean ecosystems because they form diets for marine animals from jellyfish to baleen whales. The plankton feed on iron-rich volcanic ash as well as other nutrients, like nitrates and phosphates. At the time of the eruption, there weren’t enough of these other nutrients in the water for phytoplankton to flourish, but if the eruption had occurred earlier in the year, when nitrates and phosphates were plentiful, Achterberg expects he would have seen major changes to growth.

Phytoplankton are scarcer in the waters of Hawaii than up north. Nutrients tend to fall into cooler waters—which, in Hawaii, rarely mix with the warmer layers of the ocean where phytoplankton live. The ocean’s layers are stratified based upon temperature, density, chemical properties, and other characteristics, divided into columns from the surface of the water to its depths, much like layers of the earth’s atmosphere.  But Kīlauea’s lava flow could make nitrates and phosphates more widely available in Hawaii’s waters as the layers mix more than usual.

Last year, researchers found volcanic eruptions change surrounding ocean-water temperatures and stratification. Megumi Chikamoto, a visiting researcher at Utah State University and the lead author of the study, explains that major volcanic eruptions push a dense cloud of ash into the atmosphere, preventing the transmission of light—and lowering the atmospheric temperature around the eruption by as much as 1.5 degrees Celsius. This temperature change cools the ocean below the eruption as well, allowing nutrients in different water layers to blend more easily. Chikamoto found a 5 to 10 percent increase of biological diversity in Pacific waters around major eruptions.

Chikamoto cautions that such an effect is dependent on other oceanic patterns, like El Niño and La Niña, and points out that her research focused only on large eruptions that released a significant ash plume. But she would be curious, she says, to see how heat from the Kīlauea lava flow affects water temperature in the short term, especially in the area immediately around the ecosystem.

Jason Adolf, the chair of University of Hawaii-Hilo’s marine science department, is about to find out. He and his colleagues will soon begin studying the effects of all that heat, rock, and ash on the Big Island’s marine life. “I’m not necessarily expecting the see the warm-water plume devoid of life,” Adolf says. “We may see it enriched with life.”

An abundance of plankton would attract the other marine life—manta rays, whale sharks—that feed on the organisms. And the change in temperature can draw in marine animals for other reasons; although humpback whales only feed on Arctic krill and small fish, some scientists have reported seeing the whales swimming through the unusually warm columns of water around the Kīlauea coastline.

The lava hose could even be the tip of the iceberg; there may be lava flowing under the water as well. If that’s the case, the flow might mimic underwater volcanoes and hydrothermal vents that draw bustling marine ecosystems, from bacteria and barnacles to shrimp and crabs. These vents provide energy from a source other than the sun—a process called chemosynthesis. “Imagine photosynthesis without light,” Adolf says. “[The creatures] use the reduced chemicals, like hydrogen sulfide, as an energy source.” He would like to discover whether a similar process is happening with Kīlauea.

Although marine life often suffers in the immediate vicinity of an active flow, Adolf says he hasn’t heard of any cases of fish around the site being killed unexpectedly. “Anything that would be able to swim would be able to avoid it,” he points out. And while pumice and ash can restrict life after an eruption, such an event is usually temporary; ocean currents carry off sediment and marine populations usually rebound fairly quickly. Plus, Kīlauea has been erupting, on and off, since 1983. Destruction is nothing new.

Adolf is cautious about speculating on what his team’s research may reveal, but he is optimistic about the project. “My gut feeling about the lava entering the ocean is that it’s less of a harmful, threatening thing than it is a wonderful thing,” he says. “I see it as a story of one of Earth’s more fascinating turns, how life responds to this sort of event.”