New underwater microscope technology allows scientists to get an up-close and personal look at the secret lives of dancing coral, according to a study published in the July 12 issue of the journal Nature Communications.
Scientists say that the new microscope, called the Benthic Underwater Microscope (BUM), allows them to explore the underwater world in an unprecedented way. The microscope features an extremely high-resolution camera, an underwater computer with a diver interface, bright LED lights for fast exposure images, and a flexible, tunable lens that allows scientists to view underwater structures in 3D.
"To understand the evolution of the dynamic processes taking place in the ocean,” said study lead author Jules Jaffe in a statement, “we need to observe them at the appropriate scale.”
First on the list of underwater life forms to observe using the new microscope? Coral. The magnificent invertebrates may look stationary, but they are built by tiny creatures called polyps, which look similar to upside down jellyfish attached to the bottom sides of coral reefs.
Millions of polyps work together to build coral reefs by secreting calcium carbonate, with the tiny animals providing nutrients and color to the reef.
The new microscope allowed a team of scientists to observe the tiny polyps as they gently swayed, ate, and, apparently, danced.
Using the microscope, scientists were able to position themselves two inches away from the polyps and watch them as they captured tiny plankton and brine shrimp with tiny swaying tentacles.
Scientists left the microscopes out overnight in order to observe the polyps over an extended period. The images and footage gathered show the polyps’ gentle “dancing” and post-meal kisses that scientists say could be a way for polyps to share nutrients throughout the coral colony.
Images from the Benthic Underwater Microscope also revealed a more violent side to the secret lives of polyps, showing coral of different species conquering weaker specimens. In order to win more reef space, the conquering coral will emit filaments that secrete stomach enzymes to destroy the tissue of their competitors.
Researchers have used the BUM in two places thus far – the waters off of Maui and the coast of Israel. With some of the largest coral bleaching events ever recorded taking place this year, scientists were especially interested to study the hard hit coral reefs off of Maui.
With the help of their new microscopic tool, scientists discovered that in bleached areas, there is a honeycomb pattern of algal colonization (like underwater squatters, algae move in when coral is weak from bleaching) and algal growth around individual polyps on the coral.
When coral are weak, scientists found, algae are able to outgrow and smother the already struggling reefs.
Scientists are enthusiastic about the future of underwater exploration with this new microscope, which they say is a great leap forward in the tools available for seafloor study.
"This underwater microscope is the first instrument to image the seafloor at such small scales," said Dr. Jaffe’s co-lead author Andrew Mullen of the Scripps Institution of Oceanography.
"This instrument is a part of a new trend in ocean research to bring the lab to the ocean, instead of bringing the ocean to the lab," said fellow lead author Tali Treibitz of the University of Haifa.
Next up for the microscope: close-up study of coral surfaces and tiny particles in the water around them in an effort to understand how coral breathe through gas exchange.