suffocates them, and the nutrients that leach into the
coastal waters allow algae, deadly to corals, to thrive.
Biorock Technology
Biorock Technology, invented by German architect Wolf
Hilbertz, aims to enable new coral reefs to grow in places
where the natural reefs have been destroyed. The basis
of the technology is steel frames that are sunk and anchored to the ocean floor, then “planted” with coral cuttings, which ideally originate from surviving corals in
the same region. Of course this is nothing new in itself
and cannot prevent a further coral die-off.
The real strength of Biorock Technology lies in the
use of electrical current. The steel frames function as
cathodes, and weak direct current is passed through
them. The electrolysis splits the seawater up into its
components, hydrogen and oxygen, and in time a crust
of crystalline, almost concrete-like material—limestone
composed of the salts calcium carbonate and magne-
sium hydroxide—builds up on the steel framework. It is
not entirely clear why this works, but it is assumed that
the cause is the raised pH around the electrified mate-
rial. This coating grows 1–3 cm (. 4–1. 18 in) per year,
and in time forms an ideal substrate for corals to colo-
nize. Stony corals growing on Biorock reefs are reported
to have growth rates up to five times faster than those
found on natural reefs.
The MaruBis coral reef off ko saMui
A new Biorock reef created via this tried-and-true technology was planned for the biotopes damaged by coral
bleaching off Ko Samui. Although the organizations
responsible for the Biorock process (Sun & Sea e. V.,
the Global Coral Reef Alliance, and Biorock Thailand) could provide the know-how and experienced
staff for the project, the expensive financing had to
come from private support. The members of the
German reef conservation organization Marubis e.
V., founded by Sabine Sax and other marine aquar-
