The world’s reefs are dying.
The bleaching of coral reefs has been noted since the 1980s, and the pace of bleaching is accelerating. There are a variety of causes, but most of them can be linked to human activity, whether climate change, pollution, or reef damage from things like bottom trawling, cyanide fishing, and dynamite fishing.
Bleaching is caused when the algae that cohabitate coral structures with the animals that created the reef die off or lose their photosynthetic ability. If the damage isn’t too severe, they can recover. If not, then eventually, without its symbiotic partner, the coral eventually dies. Since coral forms the backbone of reef structures, when they die, eventually the reef itself starts to die.
Using electrical power and a simple metal lattice, artificial reefs can be accreted from seawater in a process very similar to how living coral build their reefs. If living coral fragments are attached to this structure, they will actually grow quicker and healthier because the electric current passing through the structure creates conditions ideal for the natural accretion process, and the coral polyp has to spend less of its own energy building the reef. Coral larvae require limestone structures to build on, or such structures at least make the process of building easier for them. This process has already been used to create artificial reefs in several locations.
While artificial reefs have been made with many other materials, including sunken ships, old cars, armored vehicles and even tires, the electro-accretion process builds a reef that is closest in composition to the natural reef.
In addition to artificial reefs, this process could be used to build mid-ocean and deep-sea structures. These could be practically anything. Some of the possibilities include wind farms, out of sight of land, or artificial islands for resort and recreational use.
One of the more interesting possibilities, however, is back to the artificial reef, this time as a floating structure in deep water. Here, an artificial ecosystem could be constructed, providing the basis for sustainable fish-farming. Build an artificial floating reef, add support structures for the people who will run it, and then start building the ecosystem. Add real coral, add kelp, and then build a food pyramid. With this isolated structure, the food pyramid could contain only economically useful members, from kelp to sardines, groundfish, tuna and cod. Simple nets could server to keep the fish in, and if a few escape, they are unlikely to endanger or contaminate native stocks. Initial costs would be high, and running it would not likely be cheap either. However, with this sort of facility, true costs are borne by the fishery, not by the ecosystem.
While converting oceanic dissolved CO2 to limestone is not an effective method of carbon sequestration (in fact, the process releases a small amount of CO2 into the air) such structure could provide the basis for carbon sequestration, by starting with an island of artificial limestone, which can be used to further store CO2 via a slightly different process than accreting it out of the ocean water.
Artificial ocean structures could become an important part of maintaining biodiversity, while at the same time providing new locations to practice aquaculture for the purpose of growing food and other oceanic products.
