Lighting the way in the deep sea

Danielle DeLeo in the lab

On a research cruise in the Florida Straits, Danielle DeLeo collected creatures from the deep sea to study their migratory behavior.

Across aquatic environments, animals swim up to shallow water at night to feed and find mates and return to deeper water during the day to hide from predators. This pattern is the largest daily animal migration on Earth. In the deep sea, this nightly journey can span hundreds of meters.

The study is the first of its kind to examine the influence of this migration on deep-sea animals and reveal how their visual systems have adapted to such a unique lifestyle. DeLeo’s findings show how the shrimp alter the expression of visible proteins and other genes as they move vertically through the water column.

Some family members of deep-sea shrimp have evolved organs that emit bioluminescent light to help them camouflage during these migrations. The shrimp mimic the light above them to distort their body profile. Predators scanning the water column below them are less likely to detect them as they migrate. These light organs have special genes and visual proteins, which help scientists understand how sensitive the shrimp are to seeing light.

DeLeo, who conducted this research as a post-doctoral researcher in the Bracken Grissom Lab in the FIU Institute of Environment, used cutting-edge genomic technologies to explore how migratory behavior affects the visual and bioluminescent systems of the shrimp.

The study supports previous findings made in the Bracken Grissom Lab, in which DeLeo is a co-author, about how these shrimp are likely detecting light with their bioluminescent light organs so they can better camouflage as they migrate.

“This work illuminates how these animals may be able to withstand highly variable conditions during this long migration, which can help us understand how these animals might be impacted in the face of global climate change,” DeLeo said.

The knowledge discovered with this experiment highlights a distinct lack of information on how migrations like this affect deep-sea creatures’ physiology. In a world where climate change impacts every creature, no matter how remote, this research gives insight into how deep-sea creatures may react in a changing climate.

DeLeo continues her work on the evolution of visual and bioluminescent systems in shrimp and other deep-sea animals as a postdoctoral researcher with the Smithsonian National Museum of Natural History.

The findings were published in Molecular Ecology.