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HILO – During the destruction of Kilauea volcano during the eruption of Kilauea volcano in the lower East Rift, scientists at the University of Hawaii and the University of Southern California found that one of the The most devastating forces of nature could also create and sustain life.
Their study, published in the Thursday edition of the journal Science, shows how millions of cubic tons of lava flowing into the ocean in the lower Puna have caused the formation of a cocktail of nutrients on the surface, resulting in massive algal blooms visible from the space. .
The NASA satellite images of the eruption showed that water around the entrance of the lava was becoming green, signaling huge amounts of chlorophyll, the green pigment of algae and dams Other plants responsible for photosynthesis, a process that converts light into energy.
A rapid-response scientific team aboard the UH's Kaimikai-O-Kanaloa research vessel conducted 24-hour operations near the entrance to the lava to test the chemistry of the ship. water and the biological response to the lava flowing into the ocean from July 13 to 17, 2018. They discovered a phytoplankton over 100 km long and 20 km wide proliferation, caused by levels of above normal nitrates, silicic acid, iron and phosphate in the water.
Since the lava itself does not contain nitrate, massive proliferation could not have been predicted.
"One of the novelties of this study is that we know that lava was … heating up in deeper, nutrient-rich waters," said Nick Hawko, co-lead author of the study and postdoctoral researcher at the University of Ottawa. 'USC, which will join the UH-Manoa Oceanography Department in January 2010.' And because (the nutrients) were heating up, they became really floating and came to the surface.
"And that kind of mechanism was not on our radar at all."
Sam Wilson, UH-Manoa's microbial biogeochemist and the other lead co-author of the study, said the phytoplankton bloom was "very closely related to lava entering the ocean."
"When the lava started to enter the ocean … we started to see the presence of this high abundance of phytoplankton," Wilson said. "When you see something like this, the two processes, the growth of phytoplankton and the entry of the lava into the ocean are intimately linked. Then it's just a matter of determining the extent of that relationship.
"It started when the lava came into the ocean and … the bloom dissipated after the lava stopped entering the ocean on such a large scale. "
"We think that phytoplankton, the seaweed of the ocean, is growing steadily, but that it is also eaten constantly by herbivores, as if the grass was being eaten by them. cows and goats, etc., "added Hawko. "This new accumulation of nutrients increased was enough for phytoplankton to accumulate. But after a few days, he will probably be eaten. "
The authors suggest that this mechanism may have led to similar ocean fertilization events in the past, associated with the formation of the Hawaiian Islands and other major volcanic eruptions.
Asked about the evolution of fish or marine mammals in the region because of the proliferation of algae, Hawko replied, "I think it's hard to say for the moment."
"Unfortunately, we could not sample the fish and determine which ones were supported by lava and which were supported by other activities on the coast," he said. "I'm not sure that we can say anything definitively, but in general, algae are in a way the basis of the marine food chain. Therefore, all other life forms that we see in the ocean, whether it is fish, whales or giant squids, depend … on this basis of the marine food web. "
In the future, the team hopes to be able to sample the newly formed pool at the bottom of the Halemaumau crater at the top of Kilauea, and to take a closer look at the seawash interactions in the laboratory. Wilson stated that this study can be examined "on several scales".
"The eruption of Kilauea 2018 has been devastating, with many homes, properties and objects destroyed," he said. "However, at the same time, lava going into the ocean fueled microscopic life, created new lands and, while destructive, was also creative. When you explore what we learned from a scientific point of view, we learned what type of phytoplankton reacted under these conditions. It is very useful for us to know. When you add nutrients or fertilizers, can we predict what types of plants grow? We can do this for the land better than for the ocean. So when nature puts us in a situation like this, it's really a test of how well we know the ecosystem.
"This is an excellent example of land-sea interaction. When you have this kind of boundary environments, like a land-sea interaction, you have the ability to create situations that do not occur on the land or in the ocean, but at those boundaries. "
Email John Burnett at hawaiitribune-herald.com
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