Developing a coral kindergarten
Jack, what did you think when SECORE approached you with its plan to develop a floating rearing pool? Was it out of the ordinary or do you often get special inquiries like that?
Jack Kloepfer: We have worked with marine scientists before. In 2002, we cooperated with the U.S. Geological Service in Florida when they were trying to figure out one of the first bleaching events. We built them some things out of clear, unsupported vinyl. Ten years later we built a floating pool that was used on the Great Barrier Reef to test the effect of ocean acidification on corals. We still did not know what was causing coral reefs to die then, but we knew it was a problem. When contacted by the SECORE team, I became even more interested and watched the movie Chasing Coral. By then I thought whether this works or not, it is worth trying. Saving an ecosystem is probably the single biggest thing that I could ever think of doing as a contribution to humanity. The implications of success of this project are beyond my comprehension! As far as coral reefs and the ecosystem are concerned, failing is not an option.
Photos: top) Test of the first pool prototype in Curaçao in June 2018 (Rita Sellares); bottom, from the left) SECORE Project Manager Aric Bickel (Vincent Lavigne); Jack Kloepfer, Founder of Jack's Plastic Welding (private); Participants of the SECORE Workshop on Eleuthera attach the pool's tarp to the inflated pontoon (Paul A. Selvaggio).
How did you tackle this project and which important aspects had to be considered?
Jack Kloepfer: I tackled it by assuming I was not very smart when it comes to what was necessary. It seems that SECORE had a plan.
Aric Bickel: It's true, we did have a plan. We had tested a preliminary pool design in 2017 and knew that our new design needed to be more resilient. We have had several successes, but the failures that we had with the previous pools were generally the result of them not being able to hold up under the ocean conditions we deployed them in. In calm or protected areas, the pools were often very successful, but when waves or currents became too strong, our pools often collapsed. We also wanted the new design to be relatively easy to set up and have the ability to be deployed in multiple ways – either attached to a dock, tied to a mooring, anchored to the bottom, etc. All configurations should be possible. Furthermore, the pool should allow for water and air movement that would keep the corals at the same temperature as the surrounding water, but we also needed to ensure that the coral larvae stayed in the pool, while keeping other organisms out. Additionally, we had to prevent rainwater getting in, so that it would not affect the salinity inside the pool. Last, but not least, we needed to make sure the pool did not have any deep corners that larvae would get stuck in.
That’s a long list of requirements.
Jack Kloepfer: Yes, we needed to get all the minds together to make it happen. That did take a lot of understanding, and many preliminary designs. We also needed to test the materials to see if there was anything toxic in the material. That was a big problem, but we have suppliers and they had the right material for the job that was water potable, not toxic, and relatively inexpensive compared to the alternative. We ended up using a PVC coated fabric instead of a Urethane coated fabric; the material is lightweight, and air tight, and can be used for potable water.
When it comes to the design of the pool, I did not expect it to be stagnant, and I expected to have to change it to make it work better, and to make it work cheaper with less labor to build. The SECORE team would talk about what they needed, and I would design an idea, and throw it out, and they would comment on the pros and cons. SECORE Research Technician Kelly Latijnhouwers was particularly helpful, because she had ideas of where the system would actually fail. We tried to avoid those failure paths, but some things were compromises. I still think there is room for improvement.
Photos: top) A SECORE floating larval rearing pool is tied to a dock in the harbour of Eleuthera, Bahamas. Its windows have not been closed with mesh yet (Paul A. Selvaggio). bottom, from the left) After its set-up, the pool is filled with up to 1200 settlement substrates (Aric Bickel, Rita Sellares).
How did you solve the various requirements and technical challenges?
Aric Bickel: Compared to our older pools we designed the new prototype to work more like an inflatable boat. It has an inflatable ring that floats the pool and a tapered design that self-orients into the current so that the waves and currents break on the "bow" of the pool where it is strongest. We also used stronger material and focused on a better welding of the seams. Circulation of ocean water is guaranteed by six large windows with screens on them. They let water in but keep other organisms out and prevent swimming coral larvae from being washed away.
Jack Kloepfer: A pitched canopy "roof" keeps the rain out. It is clamped down tight in the front and rear of the pool, where waves are likely to hit, but has gaps on the sides that allows for air exchange with the pool. The welding is done in such a way that the tank, as it drops from the inflatable, is rounded. There are no sharp corners in the tank that larvae could get stuck in. This shape is maintained by weights on the corners of the bottom frame
Right now, the pools are being tested in Curaçao, the Bahamas and Mexico. Are you excited to hear how they worked?
Jack Kloepfer: I am very interested in the field reports. There are parts that we removed after the first unit. The shape of the tank may be more labor intensive than it needs to be. Let’s see what the field teams will be reporting.
Aric Bickel: The initial results have been good. The prototype has been deployed in various configurations: tied to a dock, tied to a mooring, and anchored to the bottom. It has so far shown to be much more resilient than the other versions. We are still waiting for coral settlement data from the pools, but the deployments thus far have been very successful. Nevertheless, we have had to make some changes and improvements, but they have been relatively minor. Working with the JPW team has been good in that regard, as they have been able to incorporate some minor changes to the design as they have produced them, so that the feedback from one location can be used to improve the version of the pool that is used at other locations. Later this year we will sit down with JPW and discuss what worked well and what could be improved. We will use this information to create an even better design for 2019.
Interview: Sina Löschke; Cover photo: Paul A. Selvaggio