What makes the continued sidelining of a 2011 paper that I published with John Abbot so consequential is not simply that one study was overlooked, but that it has allowed a myth to be perpetuated.
Do we really want to live in such a society, where deceit is rewarded and honest scientific research ignored?
You can access my 2011 paper at Research Gate:
Our research was first published in September 2011, in the journal Human and Ecological Risk Assessment 17(5):1077-1094 (DOI: 10.1080/10807039.2011.605672).
Share this information with your friends, ask your local member of parliament how it could be that there has been no correction of the official record.
Norman Duke’s 2001 claims — that diuron from sugarcane was responsible for “the worst mangrove dieback of its kind in the world” — helped justify the Reef Protection Taskforce, the Reef Water Quality Protection Plan, and years of regulatory and funding decisions targeting agriculture.
Fifteen years after our detailed, peer-reviewed re-examination found no causal link and pointed instead to natural sediment burial following floods, those original claims continue to shape the public and policy narratives.
Meanwhile, Duke has built a prominent and well-funded career at James Cook University’s TropWATER centre, leading MangroveWatch, developing identification tools, and publishing on large-scale mangrove dieback events — including the major 2015–16 Gulf of Carpentaria dieback that he and colleagues attributed to extreme El Niño-driven sea-level drops and drought, not herbicides.
The absence of any revision, retraction or even engagement with the contrary evidence has meant that science which inconveniently complicates the dominant pollution story has been effectively neutralised, while the institutional and professional benefits of the original narrative have continued to flow. This is how flawed claims, once embedded, outlast the evidence that should have displaced them.
It is now 25 years since the claims first appeared that the herbicide diuron, in runoff from sugarcane farms, was responsible for the worst mangrove dieback of its kind in the world.
Those claims, centred on the Pioneer River near Mackay, were made in a preliminary report by Norman Duke and colleagues in 2001 and were heavily promoted as part of a WWF ‘Save the Reef’ campaign.
Some years ago, I explained how this campaign was conceived, by, of all people the then Crown Prince Willem-Alexander of The Netherlands, now King Willem-Alexander. I heard first hand about the scheming back in 1999 from Imogen Zethoven who at the time worked for the Queensland Conservation Council. Of course, nothing is ever quite as it seems and too much is orchestrated by what I now understand to be the ‘Epstein class’ by which I mean the unaccountable global elite. I documented some of this back in 2018, at this blog: https://jennifermarohasy.com/2018/11/theprinceandhisdumptrucks/.
Indeed, I have been documenting the conspiracy now for many years, and increasingly, what they say will happen and what they plan out, does.
A Queensland Reef Protection Taskforce was established, then the Reef Water Quality Protection Plan, and years of regulatory pressure and public funding directed at agriculture. The idea that agricultural chemicals were killing mangroves and threatening the inshore Reef became embedded in policy and public discussion.
Fifteen years ago, in 2011, John Abbot and I published a detailed re-examination of that same evidence in the journal Human and Ecological Risk Assessment. We applied the Bradford Hill criteria for establishing causation — the standard framework used in epidemiology and environmental science. We looked again at Duke et al.’s own data on diuron concentrations in the water (the bioavailable fraction that plants can actually take up) rather than the concentrations bound to sediment.
We found no statistically significant correlation with mangrove health. Duke’s glasshouse experiments had used doses millions of times higher than anything measured in the field.
The timing of the dieback matched major flood events, not steady herbicide exposure. And only the grey mangrove (Avicennia marina), with its breathing roots (pneumatophores), was affected — consistent with burial and smothering by flood-deposited sediment.
Our conclusion was straightforward: the evidence did not support diuron as the cause.
Sediment burial following floods was the far more likely explanation. The preliminary report by Norm Duke has never been corrected or withdrawn, to be sure the original claims have never been revised by those who made them.
Fifteen years on, the narrative that agricultural chemicals — particularly diuron — caused serious mangrove dieback on the Great Barrier Reef continues to circulate largely unchallenged in policy circles and media commentary.
In the meantime, real and very large mangrove dieback events have occurred elsewhere in northern Australia. In late 2015 and early 2016, more than 7,400 hectares of mangroves died along more than 1,000 kilometres of coastline in the Gulf of Carpentaria — one of the largest recorded dieback events globally. Norman Duke himself led much of the documentation of that event. The primary cause identified was a sudden and prolonged drop in sea level associated with a severe El Niño, combined with drought and high temperatures — essentially, the mangroves died of thirst and heat stress. Similar widespread dieback had occurred under comparable extreme El Niño conditions in 1982.
These events point to natural cycles of collapse and recovery driven by climate variability and extreme weather, not by agricultural chemicals.
Mangroves are dynamic ecosystems. They expand and contract with changes in sea level, rainfall, cyclones, and sediment supply. Large-scale dieback followed by recovery is part of their natural history in northern Australia.
My 2011 paper with John Abbot remains the most thorough re-analysis of the original mangrove dieback claims. It has stood for 15 years without rebuttal. It has simply been ignored.
The absence of any correction or revision from the authors of the 2001 work, even after a major natural dieback event was documented in the Northern Territory and Gulf region, says a great deal about how some narratives persist.
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The feature image shows me/Jenn Marohasy checking crab pots amongst mangroves in Weyba Creek/Noosa back in January 2021.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
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