Responding to the toxic tide: community-led knowledge-sharing

Introduction

In March 2025, I spent some time on the South Australian coast, sleeping under the stars at Waitpinga, a wild and beautiful place. But days earlier, reports of a mysterious brown foam washing up on the beach began to circulate. A local had taken to social media to sound the alarm: surfers at Waitpinga were falling ill, and leafy sea dragons and fish were washing up dead.

What began as localised reports in March soon escalated. The brown foam was identified as a harmful algal bloom, Karenia mikimotoi, and as of August 2025, it has spread to over 4,500 square kilometres around the South Australian coastline. Described as unprecedented in scale, duration and impact, and likened to an underwater bushfire, the algal bloom continues to have a catastrophic effect on marine life. 

More than 20,000 documented observations report over 450 dead marine species. Oysters, abalone, crabs, lobsters, starfish, giant cuttlefish, octopus, seahorses and sharks are among them. What we are able to observe and document washed ashore is only a small fraction of the total deaths. Most of the bodies rest on the seafloor. 

Collaborative knowledge communication: community-driven

Back in March 2025, as the brown foam spread, affected communities initially felt that official communication and action were lagging: ‘Local people were raising alarm bells, but no one was listening.’ Residents of Waitpinga and neighbouring beaches felt left in the dark by authorities. 

Feeling uninformed and unsupported, local individuals and communities mobilised to fill the information void, beginning with community-driven health and marine surveillance. Coastal residents reported unusual health symptoms and environmental changes using social media and online community forums. Live-posting photos of dead marine life acted as real-time hazard alerts for neighbouring communities. Local communities organised forums in community spaces and webinars where scientists and residents were invited to exchange knowledge about the toxic bloom. Ramindjeri Elder, Cedric Varcoe, and Narungga Elder, Angelena Harradine Buckskin, created and organised a coastal walk, together with a local environment group, to share knowledge and ‘yarn’ about healing the waters. 

Grassroots data-sharing also contributed to knowledge about the harmful algal bloom. Volunteer ecologists collected samples to share online. Recreational divers, surfers, fishers, beachgoers, and coastal residents logged GPS-tagged sightings of marine deaths. The citizen science app, iNaturalist, hosted a dedicated project that became, and continues to be, a major part of the community effort to collect and share data publicly to track and monitor the species, habitats and areas affected. More than 20,000 observations have been uploaded to the SA Marine Mortality Events project to date. These observations are assisting not-for-profit organisations and state and federal governments in their responses, and are helping scientists to understand more about the bloom and its repercussions.

Public health consequences of the bloom

As communities documented the ecological devastation, the often overlooked consequences on human health began to emerge. Residents, surfers and beach-walkers had reported coughing, shortness of breath, and skin and eye irritation, and SA Health had stated that there were no long-term human effects. However, this initial focus on physical symptoms neglected the broader health landscape. 

Grief, horror and eco-anxiety

The toxic algal bloom in South Australia has substantial mental health ramifications. Health experts describe witnessing the traumatic effect on marine life as ‘awful, heartbreaking’ and ‘deeply destabilising’ for coastal communities. Locals have expressed feeling the ‘emotional and mental toll’ from seeing the devastating effect on marine life, and describe the beaches as ‘uncanny sites of grief, horror and confusion’. 

For many, the sorrow and grief at seeing the marine deaths is compounded by eco-anxiety. Research exploring eco-anxiety in over 500 people affected by the algal bloom indicates that many of the study participants are reporting eco-anxiety in response to the toxic bloom, linking it to the broader consequences of climate change. 

Image credit: Leafy Seadragon (Phycodurus eques) by B & M McCallum uploaded to iNaturalist licensed under CC BY-NC 4.0C

Solastalgia: ‘my spirit is hurting’

For First Nations people, witnessing the bloom’s catastrophic impact on Country has inflicted significant harm. ‘Country’ is more than land, sea and sky. Country embodies a deep, interconnected relationship with a place of belonging, where people, plants, animals, cultural identity and spiritual significance are all interwoven. These inherent ties and relational bonds mean that environmental devastation disproportionately affects First Nations communities. 

The concept of solastalgia describes the distress experienced by people who, while still in their home environment, suffer due to profound environmental change. Ramindjeri Elder, Cedric Varcoe, articulated the anguish and grief at the immense loss of ‘sea kin’ (marine life): ‘My spirit is hurting for them’. Ngarrindjeri Elder, Derek Walker, expressed worry at the cultural and ecological effects of the bloom, explaining the cultural significance of marine deaths: kuti (cockles or pipis) are a traditional protein source and part of the cultural economy.

These feelings of deep anguish and grief related to solastalgia can escalate into outrage and powerlessness when climate change-driven destruction is perceived as preventable and caused by systemic failures: ‘When we witness major die off events due to external stressors our elders and Community feel both distress and outrage that this has been allowed to occur’ (Brad Darkson, Narungga Nation). For these communities, this emotional response can be exacerbated by their recognition of climate change as a continuum of colonisation, which contributes to intergenerational trauma.

The climate crisis is a health crisis

Climate change is the primary driver of the harmful algal bloom in South Australia. This has been confirmed by an independent group of marine scientists. The acute emotional, mental, spiritual, and cultural distress experienced by coastal communities, particularly First Nations peoples, is expected to recur and intensify as climate change continues to fuel marine heatwaves and alter environmental conditions. 

The World Health Organization (WHO) unequivocally states that the climate crisis is fundamentally a health crisis, and increasingly, evidence shows a strong link between climate change and adverse impacts on mental health. In particular, acute events can immediately expose individuals to serious mental injuries leading to conditions such as PTSD, depression and anxiety.

Globally, harmful algal blooms have increased in frequency and size in response to climate change and increased nutrient run-off. The ecological disaster in South Australia should be of global concern. It is indicative of the worldwide crisis concerning planetary and human health. 

Finding solutions: integrating diverse ways of knowing

If we are to respond effectively to the complex and intertwined challenges of climate change and global health, we need to embrace diverse ways of knowing. This includes broadening what we consider counts as the ‘evidence’ in evidence-based healthcare. Different ways of knowing include scientific evidence, community values, lived experience, and Indigenous knowledge (including traditional ecological knowledge). In line with this, the WHO calls for interdisciplinary and multisectoral collaboration, and respectful knowledge exchanges with First Nations people on traditional medicine and biodiversity conservation.

Indigenous knowledge systems emphasise the interconnectedness between people and place, viewing health holistically to include spiritual, mental, emotional, and physical well-being. The One Health approach acknowledges the interconnectedness between people and place, recognising that human health is intrinsically connected to environmental health, and that the health of humans, animals, and ecosystems is interdependent. The WHO advocates for, and urges investment in, One Health initiatives. Evidence supports the WHO’s call for investment, showing a positive economic link between investments in One Health initiatives and outcomes related to healthcare. 

As the toxic bloom and its adverse effects continued and became better understood, the South Australian government began undertaking a health impact assessment, and has adopted a One Health approach for its Harmful Algal Bloom Taskforce. The Harmful Algal Bloom Reference Group, which advises the Taskforce, includes multidisciplinary representatives from various sectors and communities to incorporate diverse values, perspectives and ways of knowing. Representatives include First Nations groups, Conservation Council, Seafood Industry South Australia, and RecFish SA.

Conclusion

The brown foam that first appeared on the shores of Waitpinga signalled the beginning of the decimation of marine life across vast areas of South Australia over the months ahead. As the catastrophe unfolded, and in the perceived absence of initial communication and knowledge about the disaster, communities became the storytellers, scientists, and sentinels, sharing what they saw and what they knew. First Nations voices reminded us that the health of the sea is inseparable from the health of people, culture, and spirit.

Through community-led collaborative knowledge communication, people have already begun co-creating a bank of knowledge about how to care for and coexist with our marine ecosystems, now and in the decades ahead. This bank is enriched by diverse ways of knowing, bringing together interdisciplinary scientific evidence, multisectoral perspectives, First Nations knowledge systems, lived experience and local data. 

Lessons learned from the harmful algal bloom in South Australia have broad applicability worldwide. They demonstrate the role of communities, including traditionally marginalised communities, in contributing to greater understanding of the intrinsic connections between human and environmental health. They highlight the value of integrating diverse ways of knowing to inform holistic, evidence-based approaches to healthcare. Above all, they show us that to care for people and planet we must listen, learn and act together. 

I acknowledge the Traditional Owners of South Australia and recognise their continuing connection to Country, culture and community. I pay my respects to Elders both past and present. This blog was written on Kaurna land about events that first began unfolding and impacting the Ngarrindjeri nation. I acknowledge that not all specific First Nations groups affected by the harmful algal bloom have been named in this blog, but the spiritual, cultural and health impacts they are experiencing are undeniable.

References

ABC News. (2025, March 17). Mysterious foam washes up on Waitpinga beach with reports of fish deaths and surfers falling ill. Accessed 9 August 2025.

ABC News. (2025, May 24). SA algal bloom outbreak. Accessed 9 August 2025.

ABC News. (2025, May 27). Algae bloom impact on coastal communities, South Australia. Accessed 9 August 2025.

Albrecht, G., Sartore, G.-M., Connor, L., Higginbotham, N., Freeman, S., Kelly, B., Stain, H., Tonna, A., & Pollard, G. (2007). Solastalgia: The distress caused by environmental change. Australasian Psychiatry, 15(1_suppl), S95–S98. 

Auplish, A., Raj, E., Booijink, Y., de Balogh, K., Peyre, M., Taylor, K., Sumption, K., & Häsler, B. (2024). The economic value of One Health initiatives: A systematic review. One Health.

Australian Institute of Health and Welfare. (n.d.). Climate change: Mental health summary paper. Accessed 9 August 2025.

Biodiversity Council. (n.d.). 7 actions needed to respond to SA algal bloom. Accessed 8 August 2025.

Bourque, F., & Cunsolo Willox, A. (2014). Climate change: The next challenge for public mental health? International Review of Psychiatry, 26(4), 415–422.

Cianconi, P., Betrò, S., & Janiri, L. (2020). The impact of climate change on mental health: A systematic descriptive review. Frontiers in Psychiatry, 11, Article 74.

Cosh, S. M., Ryan, R., Fallander, K., Robinson, K., Tognela, J., Tully, P. J., & Lykins, A. D. (2024). The relationship between climate change and mental health: A systematic review of the association between eco-anxiety, psychological distress, and symptoms of major affective disorders. BMC Psychiatry, 24, Article 833

Croakey. (n.d.). Health experts sound alarm on algal bloom crisis: Calling for climate action and comprehensive responses Accessed 9 August 2025.

Flinders University. (n.d.). When the sea hurts, we hurt: Marine losses hit hard. Accessed 9 August 2025.

Gobler, C. (2020). Climate change and harmful algal blooms: Insights and perspectives. Harmful Algae, 91, 101731. 

Human Rights Research. (n.d.). Indigenous survival in the face of environmental damage. Accessed 9 August 2025.

iNaturalist Australia. (2025). SA marine mortality events 2025. Accessed 10 August 2025.

Lawrance, E. L., Thompson, R., Newberry Le Vay, J., Page, L., & Jennings, N. (2022). The impact of climate change on mental health and emotional wellbeing: A narrative review of current evidence, and its implications. International Review of Psychiatry, 34(5), 443–498.

Ngarrindjeri. (n.d.). Ngarrindjeri. https://www.ngarrindjeri.org.au/ Accessed 8 August 2025.

Patrick, R., Snell, T., Gunasiri, H., Garad, R., Meadows, G., & Enticott, J. C. (2023). Prevalence and determinants of mental health related to climate change in Australia. Australian and New Zealand Journal of Psychiatry, 57(5), 710–724.

PIRSA. (n.d.). Harmful algal bloom science forum summary [PDF]. Accessed 9 August 2025.

Redvers, N., Aubrey, P., Celidwen, Y., & Hill, K. (2023). Indigenous peoples: Traditional knowledges, climate change, and health. PLOS Global Public Health, 3(10), e0002474. 

SA Health. (2025, May 30). Health practitioner fact sheet: Marine algal blooms – Karenia mikimotoi [PDF]. Government of South Australia, SA Health. Accessed 9 August 2025.

The Conversation. (2025). Like an underwater bushfire: SA’s marine algal bloom is still killing almost everything in its path. Accessed 9 August 2025.

The Saturday Paper. (2025, July 26). SA’s algal bloom marine disaster. The Saturday Paper. Accessed 9 August 2025.

Upward, K., Usher, K., Saunders, V., & Maple, M. (2024). Understanding solastalgia from a decolonised, Indigenist lens: A scoping review. Frontiers in Public Health, 11. 

World Health Organization. (n.d.). Biodiversity — Indigenous knowledges. Accessed 9 August 2025.

World Health Organization. (n.d.). Climate change and health [Fact sheet]. Accessed 9 August 2025.

World Health Organization. (n.d.). One health Accessed 9 August 2025.

World Health Organization. (2023, November 3). WHO urges investing in ‘One Health’ actions for better health of the people and the planet. World Health Organization.

To link to this article - DOI: https://doi.org/10.70253/MMYQ6126

Conflict of interest

Heather is a member of the World EBHC Day Steering Committee.

Disclaimer

The views expressed in this World EBHC Day Blog, as well as any errors or omissions, are the sole responsibility of the author and do not represent the views of the World EBHC Day Steering Committee, Official Partners or Sponsors; nor does it imply endorsement by the aforementioned parties.