Since 1950, more than half of the world’s coral population has been reduced by over 50 percent. Researchers across the globe are looking at new technologies to help solve the problem, which would lead to less worldwide oxygen production, fewer coastlines and the collapse of the fishing industry. The National Oceanic and Atmospheric Administration (NOAA) is one of many organizations that have discovered the benefits of 3D printing to aid in this effort.
Coral reefs and 3D printing have a decade-long history. In 2012, the first 3D-printed coral reefs were sunk in Bahrain. The evolution of 3D printing has continued to benefit coral researchers, including 3D printing a supportive carbonate skeleton. With time not on the side of corals, NOAA announced in August that it is using the technology to help speed up the process of standardizing research and developing a more threat-resistant species.
To collect and study data on coral fitness and develop methods to enhance resilience, the team needed cost-effective and accurate equipment both in the lab and the ocean. These parts needed properties that could withstand ocean movement and corrosive salt air and water.
Subsurface automated dual water samplers (SASs) are a vital tool for NOAA. They are placed in the ocean to constantly check the water’s flow rate, light, temperature and acidity levels. Those results are analyzed back in the lab, where researchers can adjust the lab aquariums to reflect current conditions.
Unfortunately, these water samplers have typically come with a price tag. NOAA would manufacture a SAS out of waterproof acrylic and stainless steel hardware, which could cost more than $1,000. To cut these costs, labs would transition to hand-feeding corals throughout the night and collecting ocean water samples by hand, which is nearly impossible to synchronize and accomplish at the desired frequency.
Enochs and his team received a grant to design and build a low-cost alternative to traditional sampling systems. Enter 3D printing.
“We had several challenges to overcome with this project,” says Enochs. “We needed to design something that was accessible and straightforward yet capable of collecting climate-quality data during challenging ocean conditions.”
Using the Engineering Design Process (EDP) and free design software, the team created an open-source SAS that is field programmable. A key component during the design process was that it would be easy for a single diver to use and would be open sourced so that it could be refined and used by other researchers. The result was a 3D-printed SAS that performs in seawater at depths up to 55 m, collects two separately preserved samples, and logs temperature at the time of collection. According to the researchers, the brain of the sampler is a Teensy microcontroller, which enables automated sampling. Initially, the parts were printed with fused deposition modeling (FDM) prints. These prints were not waterproof, and water slowly seeped in and damaged the delicate internal electronics.
Formlabs’ Form 2 and Form 3 stereolithography (SLA) printers were able to solve this problem. The printers’ resin curing process makes parts completely waterproof. For parts that endured more wear and tear, Formlabs’ Fuse 1 printers and Nylon 12 powder were used. This sintered nylon provides extreme structural rigidity and thermal stability to protect the valuable machines inside the 3D-printed exteriors. These 3D-printed samplers cost around $220.
“3D printing allowed us to maintain the complexity of the research we wanted to carry out and do it for a fraction of the cost,” says Nate Formel, senior research associate at NOAA.
“That’s one of the awesome powers of 3D printing,” says Formel. “We could control water in an identical manner for a bunch of ‘sub-tanks’ within our original tank. Replication is such an important part of science—to test and retest things. When you can replicate [your] experiment many times over, you have a statistically robust way to do your science.”
The ability to cost-effectively print housings that were watertight enabled the team to develop automated husbandry. They designed a 3D-printed splash-proof feeder that provides the coral with food during the night and standardizes the feeding time across all the tanks. With less time spent on labor, the team has more time to focus on developing new coral species instead of routine tasks like feeding and sampling water.
A third 3D-printed component the team developed was a waterproof stir-plate housing. Although a stir plate is a common part, it is traditionally an expensive one when it must be waterproof. Used in a closed chamber, a stir plate controls and automates the water mixing process to ensure uniform water conditions.
Using a Formlabs printer, NOAA researchers were able to create their own. The part is composed of a computer fan motor with its wire enclosed in a 3D-printed housing. The lid is secured with an O-ring and acrylic faceplate that is sealed with epoxy to ensure a waterproof seal. The initial nylon housing was tested for its corrosion resistance and strength. The part stood up to both. This innovative part requires only about $30 worth of material.
While the up-front costs of 3D printers may have initially caused a few eyebrows to rise, using them has resulted in significant cost savings for the NOAA team. In addition to being able to optimize the print bed and powder refresh rate, the team has noticed material savings. The team is able to use powder from previous prints, typically around 70 percent. This means that only 30 percent of new powder is needed per part.
“We haven’t had to get more material since purchasing the machine,” Formel says. “The recycle rate is so helpful, and we shoot for optimal packing density. It translates directly into a low cost per part.”
Knowing that saving the corals requires more than just one team, the NOAA researchers have made their recent advances available to other labs. NOAA offers a detailed explanation of building the SAS for any lab. The design also enables different teams to make adjustments for their specific research.
While this latest project has yielded success, NOAA and other groups will continue to look to new technologies for additional solutions.
“Our goals remain the same,” Enochs says. “The way we accomplish them is evolving. We are committed to solving climate change on coral reefs and to making our research accessible to all.”