The Shinkoku Maru
sits on the ocean floor of Truk Lagoon 40m below the surface and is one of the most popular dive sites in the Federated States of Micronesia in the central Pacific.
Dr MacLeod has spent 37 years studying the decay of materials in the cultural landscape and was concerned that any hydrocarbons stored in the Shinkoku Maru
could be released into the coral lagoon as the ship decays.
“After 70 odd years sitting on the ocean floor things that were designed to be used dry are not in good shape,” Dr MacLeod said. “The added force of typhoon-driven waves could tear the decaying ship apart. If there was still fuel in the tanks it could mean disaster for the environment and the island economy that subsists on fish and tourism.
“But after so long, we really didn’t know if there was any oil or diesel left in the ship.”
Dr MacLeod was able to obtain samples from the fuel tanks and inside the engine room on the ship thanks to film makers Allison and Chris Selman. The Selmans collected samples at 35m, by diving with Nitrox tanks.
ChemCentre analysed the samples and found a mixture of diesel and a heavier product, probably motor oil, lubricating oil or bunker fuel.
“Our analysis shows that a significant amount of biodegradation has taken place,” Leif Cooper, ChemCentre’s Lead Petroleum Chemist, said.
Dr MacLeod said the results of the analysis would be used to help formulate a plan for in situ bioremediation – essentially to speed up the natural processes that are already degrading the old fuel.
“We are waiting to find out what bugs have been working down there, and we’ll then be able to help them along,” he said.
“When the Selmans collected the samples, they assessed through corrosion measurements the applicability of attaching some sacrificial zinc anodes to the ship’s hull. The results were encouraging. These anodes will stop the corrosion and buy us time while we gather funds for the bioremediation.”
For more information on the work ChemCentre’s petroleum chemistry team out carries out for clients and research, visit the Marine Environments page
of the website.
The Shinkoku Maru wreck has been colonised by coral, making it a popular dive site. Allison & Chris Selman: www.glassbottomfilms.com.au