Unique Underwater Microscope

New microscope catches underwater corals fighting.
Karin Heineman, ISTV Executive Producer

(Inside Science) -- Andrew Mullen, Ph.D student at Scripps Institution of Oceanography in San Diego, California, has been around the ocean his whole life. He grew up along the California coast, surfing waves, soaking up the sun and living the dream. Studying the ocean is his passion.

“In the marine environment, there’s a lot of really small scale processes that affect large ecosystems. For example, coral reefs, while they can extend hundreds or thousands of miles, they’re built by individual coral polyps that are around a millimeter in size,” said Mullen.

According to Mullen, “Currently, if you want to study an individual coral polyp, you take a sample from the reef and bring it back to the lab. But, that sampling process in itself is going to disturb the organism a lot. So if we want to really understand how an organism’s interacting in its natural settings, we have to observe it in its natural settings.”

To help get a better, up-close look at tiny sea life -- but without disturbing this delicate underwater world -- he developed a new underwater microscope that brings the lab to the ocean.

“That was a major motivating drive for me to want to get in this field, to build instruments that I could use in the natural environment. And actually get to design it all in the lab and then go and take it into the field and use it myself,” said Mullen.

He's already taken some unique images and video of some never-before-seen processes of tiny sea life, just as they occur natural in the ocean.

“With the instrument we’re able to observe things as small as individual zooxanthellae, and those are symbiotic algae that live inside coral polyps. And so they are around ten microns in size, and the width of your hair is around a hundred microns, so about the tenth of the width of a hair,” stated Mullen.

He also stated, “There are several unique components about the instrument that allow it to take these microscopic images underwater. We use this electrically tunable lens to help us focus. And what that is, is a soft lens that can change its shape, similar to how your eye changes its shape, and that allows us to very quickly change the focus of the instrument underwater.”

He's taken the microscope on a few journeys already, capturing amazing images of the secret life of corals.

“We use the instrument a lot in the Red Sea and there we looked at coral polyp behavior and interactions. When you place colonies next to each other the coral polyps will fight for territory. One of the things the corals do, they eject their gut onto the competing coral next to them and they are able to digest that coral and kill it,” said Mullen.

But coral behavior isn't all he captured. After record-setting high ocean temperatures caused one of the largest global coral-bleaching events ever, the microscope was used off the coast of Maui to reveal the unseen damage algae can do.

“After corals bleach they’re still alive, but they are in a very weakened state, and they are susceptible to being overgrown by algae. And we were able to look at patterns by these algae were overgrowing the corals. Which hopefully will give us a new perspective and some new information about how the algae are actually able to kill and overgrow these corals.”

Finally Mullen said, “What drives the work of our lab, is that we develop instruments for scientists to use. So, we see it as our goal to develop new tools to help scientists better understand the world around them.”

Author Bio & Story Archive

Karin Heineman is the executive producer of Inside Science TV.