Wednesday, December 6, 2023


Where your horizon expands every day.


Reworded: Environmentally-friendly sensors could be used to explore the oceans in a more sustainable manner.

A sail-shaped prototype of an ocean sensor floats in a pond

Countless sensors cover the ocean, gathering a range of information about its conditions: motion, illumination, heat, noise, weight, and chemical makeup. As efforts to obtain greater knowledge about the ocean intensify, governments, scientists, and researchers are using energy-efficient, affordable sensors, many of which are left behind.

When sensors are left on the ocean floor, washed up on shore, or end up in a garbage patch, they go from being useful tools to becoming waste. Making sensors biodegradable could help balance the need for ocean monitoring while minimizing their impact on the environment.

Scientists from Johns Hopkins University Applied Physics Laboratory are designing a prototype sensor using a unique material called an elastomer. This material is environmentally-friendly and will decompose without causing harm. The sensor, inspired by the Velella velella jelly-like creature, has already been used in the Atlantic Ocean near the Azores to gather information on salinity and temperature.

Leslie Hamilton, an engineer in the field of materials science, is part of the team for the Velella project at the Johns Hopkins University Applied Physics Laboratory. They aim to find a middle ground between creating a strong material that can withstand the elements and one that can break down once it has gathered sufficient data.

According to Hamilton, if the project is granted additional funding, users will be able to distribute future versions of Velella sensors in large groups known as “schools.”

Adding Ocean Trash

It is acknowledged that we have not been fully sampling the ocean for several decades.

Melissa Omand, an oceanographer at the University of Rhode Island who specializes in creating innovative ocean sensing equipment, stated that the implementation of fleets of on-site sensors reflects a rising pattern in ocean observation.

The strategy provides precise sensing capabilities to observe climate change phenomena that cannot be captured by remote sensing. For example, the exchange of heat between the atmosphere and ocean surface takes place on a scale of 10 kilometers, which can only be detected by ocean sensors. Satellites that operate on a larger scale of 100 to 1,000 kilometers are unable to measure the smaller-scale dynamic processes that contribute to climate change. Omand emphasized the importance of deploying a large number of ocean sensors to collect data and create a comprehensive understanding of these vital processes.

Omand stated that there is an acknowledgment that the ocean has not been thoroughly sampled for numerous decades.

Unfortunately, it is a sad reality that abandoned ocean sensors contribute to the problem of marine debris, according to Omand. This is because these tools are often seen as disposable. Recovering these sensors requires significant financial expenses and also results in carbon emissions from ships, which can sometimes even exceed the environmental harm caused by leaving them in the ocean.

The majority of Argo floats descend to the bottom of the ocean, contributing approximately 1.6 metric tons of plastic to the sea each year.

Approximately 3,800 functional Argo floats are managed by various systems, including the Global Ocean and Global Climate Observing Systems and the United Nations World Climate Research Programme. These devices, measuring about a meter in height and resembling yellow syringes, are distributed around the globe to record water temperature, salinity, and pressure. After their batteries expire (after a maximum of 6 years), most Argo floats sink to the ocean floor. Despite being made mostly of aluminum, the floats still contribute an estimated 1.6 metric tons of plastic to the ocean each year. These synthetic plastics are believed to take hundreds or even thousands of years to decompose. However, according to Argo’s environmental impact statement, using Argo floats is currently the most cost-effective and environmentally friendly method of observing the global subsurface ocean.

Environmentally Conscious Materials

A 3D printer with a petri dish below it

The Meyer Lab at the University of Rochester designed and constructed a 3D printer that can create patterns of microbial cells on or around bioplastic objects. This allows the user to manipulate the degradation rate of the biopolymer. Credit: Adam Fenster/Meyer Lab

In the year 2021, Omand established Nereid Biomaterials with the goal of developing bioplastics that can decompose in marine environments. The team consists of diverse specialists who are committed to this cause. They have successfully created biomaterials using a polymer called polyhydroxybutyrate (PHB), which is naturally produced by bacteria and can be broken down by marine microbes.

According to Anne Meyer, a biologist at Nereid Biomaterials, it takes 135 years for 2 kilograms of polylactic acid (a type of plastic) to break down in the ocean. However, 2 kilograms of PHB degrades in only 7.5 years, which is 18 times faster. Meyer’s lab at the University of Rochester is using 3D printing to study living bacterial cells and their potential to control and speed up biodegradability.

Over the next few months, several of Nereid Biomaterials’ partners in the industry have pledged to place their equipment made from PHB into the ocean. They will then observe and wait to see how effective the biodegradable plastics are and if they will set a new standard for sustainability in ocean monitoring in the future.

—Lisa Aubry, Science Writer

This article was created thanks to the assistance of the David Perlman Virtual Mentoring Program from the National Association of Science Writers.

Reference: Aubry, L. (2023), Biodegradable sensors could have a more environmentally-friendly impact on ocean exploration, Eos, 104, Published on October 26, 2023.

Text © 2023. The authors. CC BY-NC-ND 3.0
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