Coastal and shallow marine ecosystems are separated by stretches of deep water that their inhabitants cannot cross. Something must occasionally ferry them. is a candidate, because an explosive submarine eruption produces rock that floats for months. The 2006 eruption of Home Reef Volcano in Tonga provided a natural experiment, and the resulting raft was tracked across the southwest Pacific. What was riding on it?
More than 80 species, over more than 5,000 km. The authors constrained the trajectory and the rate, biomass and biodiversity of the transfer, finding over 80 species and a substantial biomass making a journey of more than 5,000 km in seven to eight months. Differing microenvironments on the pumice, caused by how stable each clast sat at the sea surface, promoted diversity in what managed to settle there.
Shallow marine and coastal ecosystems are isolated from each other by deep water their inhabitants cannot cross unaided. Pumice is an extremely effective agent that can dramatically increase the dispersal range of marine organisms and connect those isolated ecosystems, which makes a major rafting event worth catching while it happens.
The 2006 explosive eruption of Home Reef Volcano in Tonga produced one. The resulting raft traveled across the southwest Pacific, and the authors were able to constrain its trajectory along with the rate, biomass and biodiversity of what it transferred.
More than 80 species, along with a substantial biomass, made a journey of more than 5,000 km in seven to eight months. That is fast for a distance that otherwise functions as a barrier, and it carried a community rather than a few hardy stragglers.
The diversity had a physical cause. Differing microenvironmental conditions on the pumice, produced by the relative stability of individual at the sea surface, promoted diversity in . The authors draw out implications for colonization processes and their success, for managing sensitive marine environments, and for invasive pest species. Note what the study documents: transport of organisms, not whether they established themselves at the far end.
wat. A raft of floating volcanic rock carried over eighty marine species more than five thousand kilometers across the Pacific in eight months.
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It puts a number on a dispersal mechanism that is usually invoked vaguely. Eighty species crossing five thousand kilometers in under a year matters for how reefs get colonized and for how invasive species arrive.
How do we know?
Bryan and colleagues tracked the pumice rafting event following the 2006 explosive eruption of Home Reef Volcano in Tonga, constraining its trajectory and measuring the rate, biomass and biodiversity of the organisms it carried.
What is still unknown
A single eruption and a single raft, observed opportunistically. What arrived on the pumice is not the same as what established itself, and the study documents transport rather than successful colonization.
Learn something?
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