Over the past few decades, algae have been slowly edging corals out of their native reefs across the globe by blocking sunlight, wearing the corals down physically, and producing harmful chemicals. But in recent years, a new type of algal threat has surfaced in tropical regions like the Caribbean-one that spreads quickly and forms a crust on top of coral and sponges, suffocating the organisms underneath and preventing them from regrowing.
In an article publishing in the journal Current Biology on November 6, a team of marine biologists report that peyssonnelioid alga crusts, or PACs, are expanding quickly across reefs worldwide, killing off corals and transforming entire ecosystems.
"PACs are an ecological surprise arriving late to the scene of widespread ecosystem degradation of coral reefs in the Anthopocene epoch," writes the team, led by Peter Edmunds of California State University, Northridge. "Within this seascape, PACs may serve as an ecological catalyst that could hasten the global demise of corals on reefs under accelerating climate change."
One of the most challenging aspects of the emerging PAC threat is that the algae can be incredibly hard to identify. There are an estimated 48 different species of PACs, and they can be difficult to tell apart from harmless species like seaweeds because their morphology varies significantly when it comes to color, shape, and structure.
"PAC outbreaks appear to be a rapidly developing crisis on coral reefs throughout the world, where they are exploiting the ecological legacies of decades of reef degradation," write the authors.
Already, between 2012 and 2019, PACs took over 47%-64% of the shallow reefs in St. John, US Virgin Islands. And given the fact that PACs appear to be much more resilient than other related species to the impacts of climate change, including ocean acidification and extreme weather events like hurricanes, the researchers predict that PACs will eventually dominate reefs worldwide. "The recent increases in cover and distribution of PACs on tropical reefs demonstrate their capacity to accelerate the restructuring of tropical benthic habitats," they write.
To slow the spread of PACs and protect the reefs, the authors stress the importance of detecting PAC outbreaks as early as possible. They also encourage researchers to look into the transformative impact of PACs on benthic communities and learn more about tropical reef resilience against PAC outbreaks.
"Suitable progress in these areas will only be obtained by a well-funded synergy of ecological, phylogenetic, and multi-omic studies that must start with the ability to quickly and accurately identify the taxa driving the global advance of PACs," write the researchers.
Research Report:The rising threat of peyssonnelioid algal crusts on coral reefs
Artificial Intelligence Analysis
Objectives:
To understand the current state of coral reefs and the new threat posed by Peyssonnelioid algal crusts (PACs) across the globe, and to assess the risks and potential solutions for mitigating the impacts of the PACs.
Current
State-of-the-Art and Limitations:
PACs are an ecological surprise arriving late to the scene of widespread ecosystem degradation of coral reefs in the Anthropocene epoch, and they are exploiting the ecological legacies of decades of reef degradation. PACs have been displacing corals in tropical waters worldwide, and given their resilience to the impacts of climate change, they can be incredibly difficult to identify and mitigate.
Whats New in the Approach and Why it Will Succeed:
A team of marine biologists led by Peter Edmunds of California State University, Northridge are publishing their findings in the journal Current Biology on November 6, which will identify the scope of the problem and potential solutions for mitigating the impacts of the PACs.
Target Audience and Impact if Successful:
The target audience is scientists, policymakers, and other stakeholders in the conservation of coral reefs. The impact if successful will be improved resilience of coral reefs and a better understanding of how to mitigate the impacts of PACs.
Risks Involved:
The risks involved in pursuing this approach include the possibility of exacerbating the impacts of climate change, the difficulty in identifying PACs, and the lack of knowledge regarding potential solutions.
Cost of Pursuing Approach:
The cost of pursuing this approach will depend on the research methods used and the scope of the research.Timeline for Achieving Results:
The timeline for achieving results will depend on the scope and resources available for the research.Mid-Term and Final
Success Metrics:
Mid-term success metrics could include increased knowledge of PACs, identification of potential solutions, and improved resilience of coral reefs. Final success metrics could include the implementation of solutions and the reduction in the impacts of PACs.
Score for Ability to Interest DARPA: 8/10
