By Erica Mather 20/05/2016

As thick heavy fuel oil washed ashore in the wake of the Rena grounding on the Astrolabe reef, smothering beaches and birds along the Bay of Plenty coast, public outrage mounted.

Intense media coverage put pressure on environmental managers to answer difficult questions: what was the extent of the impact? How long would it take for the marine environment to recover?

Almost five years ago, the MV Rena grounding resulted in the most severe oil spill to have ever occurred in New Zealand history.

A special collection of papers has been newly published in the New Zealand Journal of Marine and Freshwater Research, forming a body of research that investigates the effects of oil, contaminants and debris during the aftermath of the Rena grounding on the 5th October 2011. This collection is the product of a research partnership, made up of tertiary institutes and iwi called Te Māori Moana that was established after the grounding.

Although the wreckage of the Rena was not the major maritime disaster that was predicted, together this research identifies the lessons that can be learnt from a disaster such as this. For it would be a waste to miss the opportunity to improve New Zealand’s response to shipwrecks in the future.

Coalition of the willing

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A Seasprite helicopter performs a recce flight over grounded ship Rena. New Zealand Defence Force

As soon as the Rena ran aground, research began with scientists forming a ‘coalition of the willing’ – a multi-disciplinary group with skills in ecology, chemistry, physiology, toxicology and ocean modelling to assess the effects of contaminants that were released from the wreckage in real time.

A mandate from the Minister of Environment was put forward to recognise the mauri of the environment (‘life force that binds all things’) in an unprecedented move for New Zealand and maritime disasters worldwide. The full effects of the Rena disaster were monitored in the hope that a return of the environment to its original state could be achieved.

The authors describe how the effects of oil spills are increasingly complex as oil mixes with a number of contaminants, forming a toxic brew that spills from the ship. In addition to oil, dangerous goods carried as cargo pose another serious threat to the marine environment. A range of expertise was required to deal with the multi-faceted impacts as they unfolded.

Oil pollution

The collection of studies describes both acute and chronic effects that marine species face as a result this disaster. The oil spill from the Rena wreckage, although a major disaster for New Zealand, was ‘relatively minor by world standards in terms of the volume of oil lost to sea’. The sight of oil unnaturally lapping at the shore initially drove the environmental fears of the public and stakeholders. Oil pollution would mean a long-term loss in biodiversity and a hit to the local economy due to the devastating impact on fisheries and harvested shellfish.

Despite the concerns of local Bay of Plenty people, there have been few long-term ecological impacts of the oil on coastal species or their habitats. The authors explain that there is no evidence of the severe consequences at an ecosystem-level like those seen after other major oil spills.

This favourable outcome is likely owing to a number of factors including the swift implementation of a model of coastal water movement in the early phase of recovery as it enabled the scientists to predict where the oil would wash ashore. Fortunately, oil arrived on a densely populated stretch of coastline rather than one more remote, meaning that a workforce was ready and able to step in for immediate recovery action. The teamwork of the recovery crew meant that little evidence of oil was observed along the coastline just three years after the disaster.

“The resilience of the Bay of Plenty coastal ecosystem to oil effects, albeit over short periods of time, was significant.”

Boots on the beach

Under increasing demand from the public to be able to contribute to the recovery effort, Maritime New Zealand (MNZ) allowed volunteers to join the official response plan. This unusual decision resulted in the first volunteer team to respond effectively to an oil spill and played an integral part in the clean up. This not only gave the community a sense of meaningful involvement, it also reduced the severity of the ecological impacts brought about by the oil. This is because the largely human-driven response kept heavy machinery from driving the oil deeper into sediments.

Army soldiers cleaning Papamoa Beach after oil from the grounded ship Rena reached shore.
Army soldiers cleaning Papamoa Beach after oil from the grounded ship Rena reached shore. Wikimedia

The legacy

“It is now clear that the legacy of the Rena is actually not the oil but the ship and its cargo.”

The site around Astrolabe Reef where remnants and contaminants from the Rena still remain represents the greatest environmental legacy from this disaster. The authors describe significant, localised contamination identified in sediments, the water column and in the biota of the reef.

Of specific concern is the presence of a ‘potent and persistent toxin’ called tributyltin (TBT), a compound that was added to anti-fouling paint until it was banned globally in 2008 due to its extreme toxicity. Anti-fouling is a coating that is applied to the hull of ships to prevent the over-growth of organisms. TBT has been found in sediments and biota over a considerable portion of Astrolabe reef at higher levels than what has caused ‘adverse physiological effects in organisms elsewhere’.

The salvage operation is now nearing completion. Parts of the wreck and its debris have been recovered down to depths of 30m. Below this depth lie the remains of the Rena, together with the components of the ship and its cargo – some with the potential of causing significant long-term environmental effects. The authors explain that cargo ships carry many potential pollutants: commercial and industrial chemicals and materials, raw minerals, oils, paints, manufactured goods, agricultural and horticultural produce, and personal belongings. Distressingly, it took many months after the Rena sank to identify all of the components of concern.

“Many of these prospective contaminants have the potential to persist in the environment for much longer than oil.”

The Rena was transporting 21 tonnes of copper clove (granulated copper wire fragments) that were strewn over the Astrolabe Reef when the hull of the ship ruptured. Unfortunately the copper could not be entirely recovered as much of it lies underneath the sunken stern of the ship. Ideally, the ecological effects of the copper will be restricted to this local area, the authors explain. Extensive adverse effects could result if the copper spreads to other sections of the reef.

What has the Rena taught us?

Good baseline data:

The research programme benefitted hugely from extensive 30+ years of monitoring data for coastal and estuarine ecosystems. This provided a starting point where measurements of toxicity and environmental impacts could be compared, thereby assessing the effectiveness of the recovery effort.

This highlights the importance of collating ecological data for high-risk areas (ports and oil platforms). The authors suggest that this information be made readily available for future emergency environmental planning, enabling a rapid response.

Effective communication:

The success of the recovery effort after the Rena disaster could be largely attributed to the early involvement of environmental scientists. Their ability to engage with the public, explain the immediate effects of the grounding and what mitigation strategies were in place played a crucial part in the rapid, cohesive response.

“When a ship grounds, oil is on the water and passions are running high. It requires real expertise, openness and numerous onsite public meetings to keep the public informed and also to let them have their say.”

The strength of a multidisciplinary team:

The power of a multi-disciplinary team proved invaluable after the grounding. The Te Māori Moana partnership eventually included a range of scientists and field teams, iwi and stakeholders. In addition, this partnership also engaged with the Rena Recovery Programme (Ministry for the Environment 2011), MNZ and the passionate volunteers from the Bay of Plenty – forming a powerful web of a recovery team.

Plan for surprises:

Following the grounding, numerous unknowns presented themselves – how much oil would wash ashore? Would the response effort be enough? Would the weather hinder or help? It was not known for several months what the largest issues were, including the full extent of the cargo.

“The situation was always and will always be complicated by the specifics of location, aspect, swell, position of the ship, extent of the damage, etc.”

Splicing science

The lessons learnt from Rena have not only been limited to the science of oil spills and their impact on the environment. During the catastrophe, science was ‘spliced’ with input and review from the public – which proved to be beneficial. The lessons from these studies are invaluable. They will improve the preparedness for future events in New Zealand, especially as shipping increases and the oil exploration industry grows.

“Documenting and gaining an understanding of the ecological, cultural and social recovery from this incident provides insight into operational responses that will aid with future shipwrecks.”


Featured image: Rena CC wikimedia

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