Biorock

During the 1970s Professor Wolf Hilbertz, an architect by training, was studying seashells and reefs at the School of Architecture at the University of Texas.

After preliminary work in 1975, in 1976 he discovered that by passing electric currents through salt water, over time a thick layer of various materials including limestone deposited on the cathode.

Over time cathodic protection replaces the negative chloride ion (Cl-) with dissolved bicarbonate (HCO3-) to harden the coating to a hydromagnesite-aragonite mixture with gaseous oxygen evolving through the porous structure.

[7] The electrical current, supplied by a low DC voltage (often <4 volts) at a low current, is required on a continuous, pulsed or intermittent basis which can therefore be generated nearby from a low-cost integrated renewable energy source such as a small floating solar panel array.

The structural element of the reef can be constructed out of low-cost rebar metal on which the rock will form which can be created locally in a shape appropriate to the location and purpose.