Signs the algal bloom that's devastated our beaches could be diminishing | 7.30

Key Concepts

• Algal Bloom: A rapid increase or accumulation in the population of algae in aquatic systems. Specifically, this report focuses on a bloom impacting South Australia.
• Citizen Scientists: Individuals who voluntarily contribute their time and effort towards scientific research, in this case, divers documenting the bloom’s effects.
• Chlorophyll a: A green pigment found in algae and plants, used as an indicator of algal biomass and bloom extent via satellite imagery.
• Sephopods: A class of marine molluscs including octopus, squid, and cuttlefish, particularly susceptible to the bloom’s effects.
• Resilience: The capacity of an ecosystem to recover from disturbance, a key area of study regarding the bloom’s aftermath.
• Invasive Species: Non-native organisms that can cause harm to the environment, economy, or human health; a concern due to the disturbed ecosystem.

The South Australian Algal Bloom: A Detailed Report

Introduction

This report details the impact of a significant algal bloom affecting the waters of South Australia’s York Peninsula and beyond, as observed by citizen scientists, marine researchers, and government officials. The bloom has resulted in widespread marine life deaths, economic losses, and ongoing ecological concerns.

Initial Impact and Observations (April – Recent Weeks)

The algal bloom first reached the York Peninsula in April, causing a rapid decline in the local ecosystem. Divers Paul McDonald and Elizabeth Solic, experienced in the area for decades, documented a devastating scene. They reported witnessing 40-50 dead octopuses and struggling fish during a single dive, describing the experience as deeply emotional. Prior to the bloom, the area was characterized as “colorful, vibrant, and full of life,” a stark contrast to the conditions observed during and after the event. The bloom caused near-instantaneous mortality in sephopods (octopus, squid, cuttlefish).

Despite the initial devastation, recent dives have shown some positive, albeit limited, signs of recovery. Divers noted “a surprising amount of fish” and small colonies, offering hope for a gradual return of marine life. However, this recovery is far from the previous healthy state of the ecosystem.

Scientific Analysis and Monitoring

Craig Stein, a marine environmental scientist from the University of South Australia, is collaborating with McDonald and Solic to analyze the environmental changes. The research aims to understand recovery processes and identify species with greater resilience to future blooms. A key concern is the creation of “bare space” within the ecosystem, which creates opportunities for invasive species to establish themselves. Monitoring utilizes satellite imagery to track chlorophyll a levels – a proxy for algal biomass – identifying hotspots around Kangaroo Island and the northern Spencer Gulf.

Bloom Dynamics and Government Response

Professor Mike Steer, leading the state government’s response, notes that while the bloom’s footprint has diminished – cell counts have dropped from millions to near zero along the metropolitan coast – caution is warranted. He emphasizes the bloom has “turned corners on us in the past” and refrains from making definitive statements until after the summer season. Initial impacts along Adelaide’s shoreline, with “tens of thousands of dead fish,” have largely cleared, leading to a return of beachgoers.

Economic and Social Consequences

The algal bloom has had significant economic repercussions. The local seafood industry estimates losses exceeding tens of millions of dollars. Tourism, particularly dive and fishing tourism in towns like Edithburg, has been severely impacted. Local businesses report empty car parks where they would normally be overflowing with visitors. The state and federal governments have collectively offered over $130 million in support. Paul and Elizabeth have had to cancel international customers, with nearly all choosing to do so.

Ongoing Concerns and Recent Developments

Despite improvements in some areas, the bloom remains active. Recent reports indicate worsening conditions along the coast of Kangaroo Island and elevated levels in the northern Spencer Gulf. Marine life, including rays and coastal fish species, continue to wash ashore, mirroring the initial stages of the bloom. Scientists are investigating whether these recent occurrences could trigger a resurgence of a larger bloom across the Gulf.

Long-Term Outlook

Experts anticipate that the ecosystem may take “years or decades” to return to its pre-bloom state. The long-term effects on species composition and ecosystem function remain uncertain. The ongoing monitoring and research are crucial for understanding the bloom’s dynamics and developing strategies for mitigating future impacts.

Notable Quotes

• “We were both in tears while we're actually diving. We saw probably 40 to 50 dead octopus.” – Paul McDonald and Elizabeth Solic, describing their initial observations.
• “It was very emotional dive. I've never witnessed this before and I hope I will never get to witness it again.” – Diver, reflecting on the severity of the event.
• “I will not dare tempt fate uh with this particular situation because it's turned corners on us in the past.” – Professor Mike Steer, cautioning against premature optimism.
• “I suspect they might take years or decades to to get back to the state where things were beforehand.” – Expert, regarding the recovery timeline.

Conclusion

The South Australian algal bloom represents a significant ecological and economic crisis. While some positive signs of recovery are emerging, the bloom remains active and poses ongoing threats. Continued monitoring, scientific research, and government support are essential for understanding the long-term impacts and facilitating the restoration of this valuable marine ecosystem. The role of citizen scientists in documenting the event has been invaluable, highlighting the importance of community involvement in environmental monitoring.