Holography Offers 3D Views Within Algal Blooms

In order to mitigate the harmful algal blooms plaguing Florida’s waters, coastal managers need to better understand and monitor them. Aditya R. Nayak, Ph.D., of the College of Engineering and Computer Science, is developing tools to peer into blooms and suss out the dynamics that allow this dangerously high level of naturally occurring organisms to grow out of control.

During his doctoral studies in mechanical engineering at Johns Hopkins University, his advisor encouraged him to explore holography, an optical imaging technique that helps unravel mysteries in the ocean.

“Think of holographic imaging system as a microscope that provides a three-dimensional information about what’s in the water,” said Nayak, who began a joint appointment in 2018 as assistant professor in the department of ocean and mechanical engineering and FAU’s Harbor Branch Oceanographic Institute (HBOI).

“The ocean is filled with billions of particles and holography is very effective in looking at spatial distributions of particles at very small scale,” he said. “These particles could be phytoplankton, zooplankton, bubbles, oil droplets, sediments or detrital material — and they are incredibly patchy in nature Characterizing their distribution and dynamics better is fundamental to addressing several critical questions.”

Within a bloom, algal cells are distributed in the same patchy manner, he said.

Nayak is collaborating with a team of FAU researchers to develop an autonomous holographic camera system that could identify individual particles within a size range of 10 microns to 2 centimeters. The system could be installed in Florida’s Indian River Lagoon, providing a record of the spatial distributions of algal species before, during and after harmful blooms.

A separate Nayak-led interdisciplinary team, including researchers at HBOI and FAU Institute for Sensing and Embedded Network Systems Engineering, plans to develop automated classification tools to analyze huge volumes of data produced by the underwater holographic system. The eventual goal is to develop an autonomous monitoring system for tracking and monitoring harmful blooms in near-real time.

Nayak characterizes his career as a series of fortuitous accidents: He came to oceanography by chance then discovered that he loved it. His good fortune has led him to an academic environment where new approaches like his are supported, he said. “FAU invests in new faculty so that they can succeed.”