The sinking of a New Zealand navy ship raises concerns about reef damage and oil leaks

WELLINGTON: The sinking of a New Zealand navy ship near the southern coast of Upolu, Samoa has raised concerns about damage to the reef and a threat to the ecosystem from oil leaks.

The 5,741 tonne displacement multi-purpose maritime support vessel HMNZS Manawanui struck a reef off Samoa last Saturday and was grounded while conducting a hydrographic survey a nautical mile from shore. All 75 people on board were successfully rescued, Xinhua news agency reported.

Samoa has confirmed that the capsized Manawanui is leaking residual oil in three places. Research shows the area of ​​physical destruction to the reef from the shipwreck and anchor chain is about half the size of a large rugby field, according to Samoa’s Marine Pollution Advisory Committee.

The effects of a catastrophic oil spill can last for a long period of time as the chemical components of the oil are absorbed by marine organisms and deposited in marine sediments. This could continue to have lasting impacts on the fitness of populations of exposed animals, Bridie Allan, a lecturer in the University of Otago’s Department of Marine Science, said on Saturday.

As oil moves on the surface due to wave and wind energy, the chemical components, including highly toxic heavy metals and polyaromatic hydrocarbons (PAHs), in the oil are weathered, leading to the release of these chemicals into the water column that marine organisms might encounter, Allan said.

Very low doses of these chemicals have been shown in several scientific studies to cause a range of physiological effects such as cardiac, spinal and craniofacial deformities, as well as behavioral disorders following exposure to low levels of PAHs, he said.

Associate Professor Nick Ling from the University of Waikato’s School of Science said there was great urgency to remove stranded heavy objects from the reef and fuel contained in the wreckage before the start of cyclone season.

“While coral reefs can naturally recover from such physical damage, this process can take many years depending on the extent of the damage, although this can be facilitated by physically reattaching coral fragments,” Ling said, adding that this would only happen once Debris from the wreck was removed and the method also depends on the ability of the divers to work in such relatively exposed conditions.

The Court of Inquiry into the sinking of the Navy ship was convened on Friday to collect and record evidence and report on the sequence of events leading to the sinking of the ship, the cause of the grounding and subsequent sinking, and details of the procedures for notification of injuries sustained and any environmental damage, said a statement from the New Zealand Defense Force (NZDF).

Built in 2003, the 84.7 meter long, 18 meter wide and 6.8 meter deep vessel has been in service with the Royal New Zealand Navy since 2019 and is primarily used for specialist diving, salvage and hydrographic missions around New Zealand According to the NZDF, it can also support missions to clear explosive remnants of war in the South Pacific.