As the UN Ocean Conference convenes in Nice, France from 9–13 June 2025, global delegates are grappling with the mounting pressures facing the world’s oceans – habitat degradation, pollution, biodiversity loss, and the destabilising impacts of climate change.
On the opposite side of the world, Norfolk Island – a tiny Australian external territory – offers an uncomfortable preview of what is unfolding elsewhere. Our small inshore coral reef lagoon is, in effect, an early warning system: small enough to observe detailed changes, and simple enough to trace many of the drivers of degradation with clarity.
Here, disease outbreaks, growth anomalies (coral ‘cancers’), declining water quality, and nutrient-driven algal blooms are progressively dismantling the reef’s ecological structure – much as they are elsewhere, but on a scale that makes the processes starkly visible. Years of neglect, deferred decisions, and unmanaged land-based runoff have contributed directly to the poor water quality now driving these changes. Norfolk’s reef shows us not only what is happening, but how quickly these shifts can occur when stressors are left unchecked.
This week, alongside the global discussions in Nice, I will post a daily series of photographs and observations documenting these changes as they have unfolded over the past five and a half years. Norfolk Island’s reef may be small, but it is a living case study – a microcosm of what many other coastal ecosystems may soon face unless serious, funded interventions are made.
The warning signs are already here. The question is whether we choose to act.
Day 2 – From small lumps to eventual collapse
Close-up of a GA
Back in June 2021, while snorkeling on the outer edge of Emily Bay, I noticed some strange lumps growing on a branching Acropora coral colony (see the photo at the top of this page). They weren’t lesions or bleaching – they were odd little bumps, scattered across the colony.
Curious, I sent some photos to coral researcher (and now one of my PhD supervisors), Associate Professor Tracy Ainsworth. She confirmed what I suspected: these were likely coral ‘cancers’ – or more correctly, growth anomalies (GAs).
Since then, I’ve been watching and photographing that coral colony as the disease has progressed. Growth anomalies develop slowly – unlike some of the faster-acting coral diseases I’ve documented here on Norfolk Island – but their long-term impact can be just as destructive. Over time, the round nodules gradually increase in both size and number, spreading across the colony.
Photographs of these growth anomalies were later used in a 2022 paper by Ricci et al., which examined how coral GAs worldwide are linked to both environmental and human-driven stressors. Some of their key findings include:
Growth anomalies can take many forms and be triggered by different factors, including parasites, degraded water quality, and water pollution.
When GAs are present, the entire coral colony suffers impaired biological function.
There is a clear link between proximity to human activity and the prevalence of growth anomalies on reefs.
Sadly, these growth anomalies aren’t isolated to this one colony. I’ve observed similar growths throughout the Emily Bay section of the lagoonal reef system. And once a colony is affected, it’s carrying a heavy burden. As Ricci et al. explain:
“Coral colonies affected by GAs carry the burden of the impaired biological function which, in extreme cases, can lead to colony-wide decreased growth rates, compromised reproduction, and susceptibility to physical damage because of weaker skeletons.”
(Ricci et al., 2022)
Weaker skeletons mean trouble when storms arrive – as they inevitably always do. At the end of May 2025, that original coral colony finally gave way (see photo sequence below). Covered in algae and structurally weakened, parts of the colony collapsed during recent swells. On 11 May 2025, you can see in the photos how much algae had already overgrown the dying coral. Just a few weeks later, the first section – the area where I first noticed those odd bumps back in 2021 – had broken off completely into fragments.
Above: looking east, Acropora colony, Emily Bay
And this isn’t an isolated event. I’ve seen the same pattern repeat elsewhere in the lagoon: corals weakened by disease, then toppled by waves. On a healthy reef, these broken fragments might become new habitat for baby corals to settle and regrow. But on a reef where water quality is poor – with elevated nitrates, phosphates, and nutrients – algae quickly colonises the dead coral, out-competing any new coral recruits before they can gain a foothold.
This is how reef degradation quietly compounds: chronic diseases like growth anomalies weaken corals structurally, storms finish the job, and algae moves in before recovery can begin – a vicious cycle playing out right here on Norfolk Island’s reef.
Above: looking west from the same spot as above, Acropora colony, Emily Bay