New Method Lets Researchers Peer Deeper into Ocean

Oct, 2020 - By SMI

In 2018, a research cruise in the Gulf of Maine used LiDAR and collected information about a type of algae, coccolithophores.

Decades ago, the researchers envisioned an underwater telescope that will allow users to look deep below the surface of the ocean. Now, the researchers have developed a new and promising way of looking at the deep waters of the ocean, establishing a new approach to measure key properties and detect algae using light. The team used a laser-based instrument, called LiDAR (Light Detection and Ranging) to collect these measurements, which is usually possible using satellites. LiDAR is a method that measures distance by illuminating the target with laser light and measuring the reflection with a sensor.

Differences in wavelength and laser return time can then be used to make three-dimensional representations of the target. When scientists or researchers monitor ecologically important events such as seaweed blooms, they use photographs taken by satellites. However, according to the research team from Bigelow Laboratory for Ocean Sciences, satellite cameras can only see around 5 to 10 meters below the ocean. In search of a better alternative, the team turned to ship-mounted LiDAR units, commonly seen on self-driving cars and robots.

LiDAR unit emits a laser beam and then measures the exact time it takes to reflect back from any object. The possible way to detect the presence of obstacles, as well as their distance. In 2018, a research cruise in the Gulf of Maine used this technology and collected information about a type of algae, coccolithophores. The organisms are surrounded by protective calcium carbonate plates, which reflect light in a specific way. By analyzing reflected laser light, the team found the presence of algae, as well as its quantity. LiDAR has since been tested successfully in other areas such as the coast of New York and the Sargasso Sea. The research was recently published in the Applied Optics journal.