Editing Coral reef (section)

===Creating substrates===
[[File:Deep_sea_corals,_Wagner_Seamount.jpg|left|thumb|Deep sea corals at the Wagner Seamount. These corals are well adapted to deep water conditions where substrates are plentiful.]]
Efforts to expand the size and number of coral reefs generally involve supplying substrate to allow more corals to find a home. Substrate materials include discarded vehicle tires, scuttled ships, subway cars and formed concrete, such as [[Reef Ball|reef balls]]. Reefs grow unaided on marine structures such as [[Oil platform|oil rigs]]. In large restoration projects, propagated [[hermatypic coral]] on substrate can be secured with metal pins, [[superglue]] or [[milliput]]. Needle and thread can also attach A-hermatype coral to substrate.

[[Biorock]] is a substrate produced by a patented process that runs low voltage [[electrical current]]s through seawater to cause dissolved minerals to precipitate onto [[steel]] structures. The resultant white carbonate ([[aragonite]]) is the same mineral that makes up natural coral reefs. Corals rapidly colonize and grow at accelerated rates on these coated structures. The electrical currents also accelerate the formation and growth of both chemical limestone rock and the skeletons of corals and other shell-bearing organisms, such as oysters. The vicinity of the [[anode]] and [[cathode]] provides a high-[[pH]] environment which inhibits the growth of competitive filamentous and fleshy algae. The increased growth rates fully depend on the accretion activity. Under the influence of the electric field, corals display an increased growth rate, size and density.

Simply having many structures on the ocean floor is not enough to form coral reefs. Restoration projects must consider the complexity of the substrates they are creating for future reefs. Researchers conducted an experiment near Ticao Island in the Philippines in 2013<ref name="Yanovski-2019">{{Cite journal|last1=Yanovski|first1=Roy|last2=Abelson|first2=Avigdor|date=2019-07-01|title=Structural complexity enhancement as a potential coral-reef restoration tool|url=http://www.sciencedirect.com/science/article/pii/S0925857419301144|journal=Ecological Engineering|language=en|volume=132|pages=87–93|doi=10.1016/j.ecoleng.2019.04.007|bibcode=2019EcEng.132...87Y |s2cid=146076500|issn=0925-8574}}</ref> where several substrates in varying complexities were laid in the nearby degraded reefs. Large complexity consisted of plots that had both a human-made substrates of both smooth and rough rocks with a surrounding fence, medium consisted of only the human-made substrates, and small had neither the fence or substrates. After one month, researchers found that there was a positive correlation between structure complexity and recruitment rates of larvae.<ref name="Yanovski-2019" /> The medium complexity performed the best with larvae favoring rough rocks over smooth rocks. Following one year of their study, researchers visited the site and found that many of the sites were able to support local fisheries. They came to the conclusion that reef restoration could be done cost-effectively and will yield long term benefits given they are protected and maintained.<ref name="Yanovski-2019" />