HARBOUR MARINE SAFARI SYDNEY / PROTOTYPE: REEF CaCO3

Digital Studio - Team: Robert Chan, Martin Gaardboe

Runner Up - 2014 AIA Digital Innovation Award

THE EARTH IS CHANGING. That much is unavoidable. The publication of data from May 2013 showing carbon levels surpassing 400 parts per million (UC San Diego 2013) - the highest ever in human history - is undisputed evidence that climate change is happening. The imminent threat of rising sea levels, global warming and ocean acidification is rendering much of the planet’s ecosystems in danger of extinction, and with them, our current way of life. 
Through this project, we uncover a dialogue about the potential for a seascape architecture that forms a symbiotic relationship with the sea by creating a self-sufficient, self-forming coral reef ecosystem. This project stems from current research on artificial reef systems by figures including Wolf Hilbertz and James Gardiner, and utilizes digital software to generate site-specific structural designs.

OBJECTIVE
Coral Reefs are in danger and with them the delicate ecosystems that rely on them for survival. This political, environmental and economic issue is one that is in the forefront of Australian politics at the moment, with the survival of the Great Barrier Reef in jeopardy. This project addresses this issue by utilising digital software for the design and fabrication of a system that will enable the recovery and prosperity of the Great Barrier Reef for future generations.

CALCIUM CARBONATE
The basis of this project is the compound Calcium Carbonate (CaCO3), which accounts for 10% of the world’s crust as limestone and is freely found in oceans. It is the fundamental compound of shell growth, bone structures and coral, where organisms absorb CaCO3 from the seawater. It is this process of CaCO3 accretion that forms the inspiration for this project. Combining research from top marine biologists as well as our own explorations, we were able to achieve small amounts of calcium accretion by running a low voltage electrical current through a steel structure submerged in sea water. Cumulative deposits of CaCO3 increase the strength of the material, ultimately achieving a similar strength to reinforced concrete. 

PROCESS
Building on research on CaCO3, we developed a framework based on a single prefabricated element resembling a coral ‘spicule’:  a four-pronged element found as the building block for a number of sea sponges and corals. This framework is proposed to be constructed as a prototype in Sydney harbour for initial analysis and testing, before being implemented in the Great Barrier Reef on a much larger scale. The Sydney climate is ideal for initial Calcium growth tests, as the water temperature and salinity create an ideal calcium saturation level, enabling a faster rate of calcium growth than locations with warmer waters.

FUNCTION
The growth of calcium on the structure enables coral to thrive, some reports indicating the success of coral on these structures to have 3 to 5 times the success of natural coral reefs (reference Goreau and Hilbertz 2005). As previously mentioned, Sydney Harbour has an ideal marine climate for calcium accretion, and the existing coral environments within the harbour are evidence that it is also an ideal environment for coral growth. Sydney harbour is also a hotspot for marine observation and analysis, ensuring regular analysis and testing of the structure can be carried out with ease, whilst the ensuing coral reef environment will become a haven for marine organisms, creating a new destination for recreational diving and tourist activities