What's below? Research from the World Health Organization shows that environmental DNA is a reliable way to understand migration in the ocean transition zone

The "transition zone" in the middle of the ocean is the key to unraveling several fascinating questions about the marine food web and the ocean's carbon sequestration capacity
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But it is extremely difficult to study this vast and remote area

This knowledge gap is beginning to narrow due to the genetic material of scales, fecal particles, or tissue fragments that are shed as organisms move through the water
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The resulting environmental DNA (eDNA) traces provide clues for researchers to understand which species are in the water and their relative abundance

"One of the main findings of our paper is that if the animal moves up and down in the water column, the eDNA signal will not disappear immediately," Elizabeth Andrewskovich Allen, a postdoctoral researcher at WHOI during the study and currently a postdoctoral fellow at the University of Washington (Elizabeth Andruszkiewicz Allan) said
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"This helped us answer some big questions that cannot be answered with trawl or acoustic data

Allan and WHOI’s physical oceanographer Weifeng "Gordon" Zhang used computer models to simulate what happens to the eDNA in the water after the host animal sheds
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They found that physical processes—air flow, wind, mixing, and particle settling—have no significant effect on the vertical distribution of eDNA

"Before this work, we cannot say with certainty what happened to the eDNA shedding of transition zone species
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But a very clear pattern is shown in the model, providing a basic understanding of how, over time, on the surface and The eDNA concentration between the deep layers," Zhang said

As one of the first studies to establish an eDNA concentration model, the researchers pointed out that more field data is needed to help test the model
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However, these promising results show how useful eDNA is in studying animal migration and carbon sequestration in difficult-to-access parts of the ocean, such as the transition zone

"These modeling results provide us with a foundation that allows us to study the ecology of the blurred ocean zone more effectively," WHOI molecular ecologist and co-author of this paper Annette Govindarajan (Annette Govindarajan) Say
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"It provides some experiments for future directions, some of which we have already started researching

Article title

Modeling characterization of the vertical and temporal variability of environmental DNA in the mesopelagic ocean