Coronodon Nano - Oligocene Whale Fall

[rhizotron]

Coronodon Nano - Oligocene Whale Fall

This new project idea incorporates themes from other small tank setups I've built recently, including microbial diversity and paleontology. My goal is to represent a few aspects of ocean abyss whale falls and their characteristic ecological interactions, while also exploring whale evolution.

Whale fall ecology is fascinating. I've gotten a good introduction to the biological processes and interactions with this article I found...

My plan for the tank setup is to use a 30", 6-gallon bookshelf aquarium with a 3D-printed whale mandible filling most of the space. Here are a couple of quick sketches I made in Photoshop...

I should probably also 3D model this for a more complete plan, although the software just makes my head hurt when I try to work on this little MacBook screen I have here. This is good enough for now.

The animal I'm depicting here, Coronodon havensteini, is another fascinating story. Here's a link to the article with the species description....

https://www.sciencedirect.com/science/article/pii/S0960982217307042

Really nice models for both the cranium and a mandible are available free for download on the Sketchfab Website. I plan to use the mandible in the tank, but the printed cranium would look really cool with a natural fossil bone finish and hung on the wall above...

Comparable in some ways to the decompositional sequence of dead trees that fall in the forest, whale falls in the deep ocean progress through stepwise ecological succession. The following is quoted from the Treude et al. article...

When deposited, large whale carcasses pass through up to 4 stages of utilization by the deep- sea community (Smith et al. 1998, 2002, Smith & Baco 2003): (1) a mobile scavenger stage, wherein scav- engers such as hagfishes, sleeper sharks and amphi- pods feed on whale soft tissue; (2) an enrichment- opportunistic stage, where remains of the whale dispersed over the surrounding sediment are utilized by an opportunistic community with high population densities but low species richness; (3) a sulfophilic stage, where microbial consumption of organic com- pounds in the lipid-rich bones as well as in the organi- cally enriched sediment sustains the production of hydrogen sulfide, which is then utilized by a chemo- synthetic community; and (4) a reef stage, where the whale bones serve as hard substrate outcropping from the seafloor and as a refuge for a variety of deep-sea animals. Whale falls represent a unique habitat with some of the highest local species richness known from deep-sea hard substrates (Baco & Smith 2003).

I can represent stage #3 and stage #4 in an aquarium. Although it will create an environment far too toxic with ammonia and hydrogen sulfide for marine animals, stage #3 can be modeled with addition of some fatty meat for microbial degradation and metabolism. With this process complete and with several water changes to create a more favorable environment, the mandible can then remain to serve as habitat structure for marine animals. I'll plan to just introduce commonly-available reef aquarium livestock as stand-ins for the deep-sea Echinoderms, Molluscs, Fish, Cnidarians and others that use whale fall skeletal habitat.

A test print of a mandible section from that same file on the Sketchfab site...

I hope this is more or less clear. I'll plan to post some more build detail ideas soon. I have some questions about best approaches for plumbing this small setup and more.

 

[Chrisv.]

So you plan to 3d print a whale jaw decoration and add meat to an aquarium to cause an ammonia and hydrogen sulfide spike, and then once it's subsided, you will introduce typical reef tank inhabitants?

 

[rhizotron]

So you plan to 3d print a whale jaw decoration and add meat to an aquarium to cause an ammonia and hydrogen sulfide spike, and then once it's subsided, you will introduce typical reef tank inhabitants?

Yes that's basically it. Obviously the water needs to be clean before adding any aquarium livestock. Since it is supposed to represent an abyssal environment, animals will not include stony corals or others dependent upon photosynthesis. With a sump there will be only about 9 gallons of water in the whole thing.

The first phase of this is intended to model the reducing environment and unique microbial metabolisms in the sediments and bones around a whale fall. It would be neat to also measure these with gas sensors and graph if I can figure that out. Dissolved H ₂S and CH₄ sensors are precision instruments and very costly, but I can get regular gas sensors and hobby breakouts not very expensive at all....

https://www.sparkfun.com/products/9404

https://www.sparkfun.com/products/17052

You can't submerge these, but if they don't corrode too fast I hope they might capture relative change or presence/absence at least if positioned in a bell over the water.

 

[rhizotron]

Here's the tank I want to use. It's roughly (not quite) 30" long by 6" wide by 8" high....

I intend to build a rectangular box with 80/20 that will hang on the wall like shelving with a space on the bottom for the tank and a second space on top for an uphill sump. I haven't tried to calculate it yet, but I imagine the 10-series with the right fasteners will be plenty strong for this. Yellow anodized aluminum would look cool...

This is tank I have in mind for a sump, a narrow (20" X 8" X 8") frag tank from Advanced Acrylics....

My plan is for a pump inside the acrylic tank to pull water up from the display to overflow back down again. Of course there's danger of siphoning back into the almost-full glass tank, but I will plumb a good-quality water check valve into it. I could also put a small hole in the return line just below the sump water level as a siphon break.

 

[rhizotron]

I cut the model into seven sections and I've only been able to print one a day--so it's taking forever--but here it is unassembled and with just two more pieces left to print...

Due to the questionable long-term durability of PLA submerged in an aquarium, I printed this in PETG. There is a little warping with ends of some sections lifting up, but I can fix that with some sanding and filling. I hope this epoxy in bright white will match the plastic color pretty close. I'm not going to paint or finish, but instead just leave it in plain plastic.

Here's a basic Photoshop sketch with the tank and uphill sump on a box shelf assembled in 10 series 80/20...

I already ordered the aluminum extrusion cut-to-size to make a double shelf 34.5" long by 11" wide by 15.5" tall. Shelf surfaces will probably be expanded .5" PVC sheet flush with the horizontal bars. That material is cheap and soft, but I hope it will work without too much sagging in that pretty small 9" inside width.

80/20 corner connectors are so expensive! I wonder about making my own outside corner braces on the CNC router with thick HDPE plastic and I show this idea here with the orange pieces. I like the idea of these as brightly colored accents. With about ten gallons of water and tanks & parts this will be approaching 100 pounds in weight, but sixteen braces like that would be a lot of strong material holding it together. Maybe I could alternatively get away with just eight internal metal braces around the bottom corners in combination with the plastic braces all secured with T-nuts(?).

 

[Jay Hemdal]

On side note: we had a bare Japanese Giant Crab exhibit (just crabs and substrate). Our director wanted to spruce things up a bit. Our museum had a whale vertebrate from the 1930's in storage. I soaked it in water for a couple of months (still oily) and then added it to the exhibit. Looked great, and giant crabs are known to use whale falls, so it matched ecologically. The crabs even scrape at it with their claws.

Jay

 

[rhizotron]

On side note: we had a bare Japanese Giant Crab exhibit (just crabs and substrate). Our director wanted to spruce things up a bit. Our museum had a whale vertebrate from the 1930's in storage. I soaked it in water for a couple of months (still oily) and then added it to the exhibit. Looked great, and giant crabs are known to use whale falls, so it matched ecologically. The crabs even scrape at it with their claws.

Jay

That's neat. Are there any pictures? Another idea I have is to add a couple real lamb bones. These would be a nice feature for the microbial phase of the project, but fresh they would pollute the water too much to work with any reef livestock. However perhaps after a more extended period for microbial degradation of most of the fat and meat I could just leave them in there and they could work as a slow-release food source, like bones in a real whale fall. Maybe.

 

[Jay Hemdal]

That's neat. Are there any pictures? Another idea I have is to add a couple real lamb bones. These would be a nice feature for the microbial phase of the project, but fresh they would pollute the water too much to work with any reef livestock. However perhaps after a more extended period for microbial degradation of most of the fat and meat I could just leave them in there and they could work as a slow-release food source, like bones in a real whale fall. Maybe.

I didn't think I had any pictures (and now that I'm retired, I don't get back to the aquarium more than once every month or two) but I found one in my outtake files...the quality isn't good, but you can get the idea I think.

Jay

 

[rhizotron]

That's pretty neat. I bet the crab appreciated the extra structure in there. I wonder about eventually adding a single arrow crab to this setup along with another invert or two that might get along. I might go with shrimp though instead.

 

[afrokobe]

very cool and unique build

 

[rhizotron]

very cool and unique build

Thanks! I hope to get the mandible all assembled tomorrow for more pictures.

 

[rhizotron]

A little more progress...

I got the mandible assembled. Actually I reprinted the whole thing because I was dissatisfied with how the first set of pieces all went together. With this second print I just turned the model 90 degrees on its side and cut into four pieces (rather than seven) and printed with a lot of support. There was no warpage with this approach and it epoxied together much better with no gaps...

That white J-B Weld is almost the exact same bright white color as the PETG.

I also got my order of 80/20 extrusions. Ordering through tnutz dot com is a much better value and I also found economy connectors on Amazon, so the whole thing goes together for less than a hundred bucks. I started connecting the pieces, but found some of them had sharp burrs on the cut ends that I need to file off, so I'll finish this up later....

 

[TheBiochemist]

Very interesting. Following for updates.

 

[rhizotron]

Very interesting. Following for updates.

Thanks!

More soon...

 

[rhizotron]

Quick update for this thing....

I've decided to abandon the whale mandible project in favor of another more compelling idea.

The tank + shelf setup is all ready to go for this other concept I have in mind. Using the figures from that paper as reference, I'm going to put a paint finish on the 3D print and then hang it on the wall somewhere.