Coral reef building

[farmerben]

How do people here feel about projects to grow coral reefs?  What are good ways to regulate and fund them?  Many youtube videos are available on the subject, many independent projects are underway in various countries.  The most common method is to cut corals on a bandsaw and grow them out on small coins of concrete.  When clones are grown in proximity, they fuse making a 3 year old coral effectively like a 25 year old coral.

Small fish love anything that gives them plenty of cover.  Some projects are dropping concrete domes into the ocean these provide extra habitat and a calcium carbonate surface on which coral can be attached even where none were before (due to sandy bottoms, etc).  What are the ethics and economics of scaling that up?  I was thinking it makes the perfect grave marker, as cemeteries use up valuable urban land.  Shallow water capable of supporting artificial habitat is abundant relative to cemeteries.  But, I question using concrete at scale.

[Terwin]

To grow coral, you just need a solid anchor(ie not sand) in a flow of nutrient rich water.

Barnacles are an example of a hardy coral that is happy to attach to ships or docks, and then thrive as the movement of the ship or waves keeps it well-fed.(until they get forcibly removed, of course)

So in theory, the idea of cement burial domes should work, but you would likely get a lot of push-back on turning the water just off of tourist-attracting beaches into cemeteries.

Because you want surface exposed to the current to encourage coral growth, I think that a thin lattice would work better than a dome(like a garden trellis, but probably more sparse), and probably something other than cement.  As this is something you want coated in coral, it should be ok if the skeleton is something that will rot a way after a time.  Even wood might work, if you can get it to last long enough without being toxic.

[farmerben]

I like the idea sinking wooden lattices.  I was thinking about that also.  The underwater cemeteries need not be located in the same place as tourist beaches, it proposed as a way to fund reef construction for more remote areas.

[kerbiloid]

1. The underwater 3d-printing drones scoop the metal ions and print the 3d-lattice.

2. The coral polyps make corals.

3. The reef reaches the surface and gets connected to other reefs.

....

4. PROFIT !!!

 

[Scotius]

Some coral growing projects use steel cages anchored to the bottom. Then weak current is sent through the metal, which somehow significantly improves growth rate of young corals.

https://www.smh.com.au/environment/steel-cages-prove-their-mettle-to-rescue-coral-20090821-ettd.html

[Terwin]

17 hours ago, Scotius said:

Some coral growing projects use steel cages anchored to the bottom. Then weak current is sent through the metal, which somehow significantly improves growth rate of young corals.

https://www.smh.com.au/environment/steel-cages-prove-their-mettle-to-rescue-coral-20090821-ettd.html

Makes sense, coral are mostly(all?) filter feeders, so some current would be required for them to survive and grow.  Also, their pre-coral stage is a bit like a tiny jellyfish, floating around looking for something to latch on to, so having a current will allow more of them to find the lattice as well.

[tomf]

It's an electric current that scotius was talking about. I think it is hypothesised that the electric charge on the substrate makes it easier for the coals to build their skeletons.

https://en.m.wikipedia.org/wiki/Electrified_reef#:~:text=An electric reef (also electrified,Goreau in the 1980s.

 

 

[darthgently]

There is growing evidence that reefs to a large degree go through natural cycles of growth that can look a lot like damage but could be analogous to a sleeping forest in winter.  We have so much more information as we are monitoring so much more across the planet, but we haven't been monitoring in such detail for very long at all geologically speaking.  So we don't know what "normal" patterns over time are in as much detail as many careers would prefer

Edited January 25, 2023 by darthgently

[steve9728]

I watched a video from Chinese National Geography about interviewing the coral researchers from the Guangdong Ocean University before. It was sponsored by a charity event called "Little Red Flower" organised by Tencent. And it just so happens that their coral breeding work takes place in my city, Shenzhen.

Spoiler

Here's the link if you want to test your Chinese skill (English subs not available except coral's Latin scientific names): https://www.bilibili.com/video/BV1PY411X74Y/?spm_id_from=333.999.0.0&vd_source=6fef304b8d0c4737896e6b702ddfbfb3 

"Firstly, coral reefs protect the coastal zone and reduce the impact of waves; secondly, although they cover less than two thousandths of the world's oceans, they support a quarter of all marine life.", said by the marine biologist in the video.

In summary, here's what they did for coral breeding:

1. Survey the environment of the area in question to identify the dominant local species and the various environmental factors that are detrimental to local coral populations. What they were breeding were Staghorn coral.
2. Cuttings from the mother coral plant.
3. Indoor propagation of coral seedlings of locally dominant species in a laboratory-like location.
4. Make the bases made of reinforced concrete and lift them to a suitable seabed.
5. Use special mastic to secure the bred coral seedlings to the base.
6. The most important part: constant attention and regular missions to the breeding waters to check on the breeding of these corals. and make the appropriate adjustments according to the different conditions involved.

Spoiler

The base itself:

Actually, the most important part I think is to do more regulating. Apart from the regulation of pollution, don't let someone throwing starfish in where you are planting coral.

[StrandedonEarth]

Starfish, er, sea stars eat coral?  Huh. Learned something new…

[kerbiloid]

They are their main enemies, and damage the reefs a lot.

[steve9728]

12 hours ago, StrandedonEarth said:

Starfish, er, sea stars eat coral?  Huh. Learned something new…

Apart from this, I have heard many stories of other species of starfish eating up shellfish from costal shellfish farms such as scallops, abalone, and clams. 

Edited January 27, 2023 by steve9728