Massive and Persistent Toxic Algal Bloom in Australia Claims Lives of Over 14,000 Animals
In the waters off South Australia's Fleurieu Peninsula, a harmful algal bloom (HAB) has been causing concern for over five months. The bloom, caused by an excess of Karenia mikimotoi, a native plankton species, has affected a hundred kilometers of coastline and spans over 5,000 square kilometers (2,000 square miles). This event is "larger and more broad-ranging" than any other HAB event in Australia's history, according to Professor Shauna Murray of the University of Technology, Sydney.
The bloom has resulted in a "dead zone" due to the organism's consumption of oxygen dissolved in water and the production of toxins that kill fish, and can harm humans. Over 13,700 dead animals, mostly fish, have been documented on the region's beaches.
Several key solutions and strategies are being employed to prevent and mitigate HABs, including the current event off the Fleurieu Peninsula.
- Reduce Nutrient Inputs: Minimizing nutrient pollution, especially nitrogen and phosphorus, is crucial in preventing algal growth. This involves reducing fertilizer use in agriculture, optimizing fertilizer application timing to avoid runoff during storms, and controlling runoff from urban and agricultural areas.
- Water Quality Monitoring and Early Warning Systems: Continual monitoring of water nutrient levels and environmental conditions allows prediction and early detection of blooms. Advanced models using climate, ocean circulation, and hydrodynamics also help forecast bloom formation and movement, enabling timely management.
- Physical Removal and Habitat Restoration: Harvesting excess aquatic plants can reduce available nutrients. Restoration of wetlands is effective since wetlands filter and break down nutrients before they enter open waters, helping reduce eutrophication that fosters HABs.
- Public Education and Regulations: Educating the community about causes and prevention of HABs and enforcing regulations to control nutrient discharges into waterways are vital for long-term management.
- Minimizing Exposure and Health Risks: Until blooms subside, public health advisories recommend avoiding contact with affected water, not consuming fish caught in bloom-affected waters without proper cleaning, and showering after exposure. Protecting pets and livestock from contaminated water is equally important.
- Water Treatment in Drinking Supplies: For water systems relying on affected sources, specialized treatment processes alongside conventional filtration are employed to remove cyanobacteria and toxins. Proactive planning and active management are required during severe events to maintain safe drinking water.
In response to the ongoing bloom, local agencies are emphasizing nutrient runoff control from agricultural and urban sources, ongoing monitoring, public advisories on avoiding affected water, and preparations for water treatment challenges if supplies are impacted.
Dr. Faith Coleman, a marine scientist from Federation University Australia, has been spending a significant amount of time debunking conspiracy theories about the cause of the algal bloom, rather than focusing on solving the problem. The federal environment minister has recently sent the head of the environment, reef and ocean division to investigate the bloom.
The disaster has far-reaching environmental and economic implications, and experts such as Dr. Zoe Doubleday of the University of South Australia consider it a disaster of national significance due to these impacts, and because the cause is unusual and not well-understood. Dr. Doubleday suggests that the bloom could meet the definition of a national disaster and qualify as a 'Matter of National Environmental Significance' under Commonwealth Environmental legislation.
Restoration of seagrasses and kelp forests is proposed as a way to prevent future algal blooms, with benefits including carbon storage. Dr. Nina Wootton of the University of Adelaide suggests solutions for the algal bloom, including reducing nutrient runoff, better coastal monitoring, acting on climate change, and restoring seagrasses and kelp forests.
Citizen scientists have recorded 458 species in an iNaturalist folder, highlighting the diverse ecosystem that is under threat from the ongoing bloom.
Dr. Coleman notes that a combination of influences made the heatwave that preceded the bloom unusual, and that rising global temperatures will likely result in similar events in the future unless greenhouse gas emissions are controlled.
As the community and scientists work together to understand and address the ongoing HAB, the hope remains that the bloom will subside and the ecosystem can begin to recover.
- The ongoing HAB event off South Australia's Fleurieu Peninsula, a national disaster of significance, underscores the urgency of addressing climate change, as suggested by Dr. Coleman, who points out that rising global temperatures could lead to similar events in the future unless greenhouse gas emissions are controlled.
- In response to the bloom's environmental and economic impacts, local agencies are focusing on solutions such as reducing nutrient runoff and better coastal monitoring, as proposed by Dr. Nina Wootton, while also highlighting the importance of restoring seagrasses and kelp forests for carbon storage and prevention of future algal blooms.
- To combat the negative effects of this HAB on mental health, health-and-wellness initiatives can be implemented within the community to address the stress and anxiety caused by the situation, as well as to promote awareness and understanding of the event.
- By collaborating with environmental-science experts and citizen scientists, who have recorded 458 species in an iNaturalist folder, the public can help in monitoring the ecosystem's recovery and fostering a greater appreciation for the vulnerable marine life under threat from HABs.
