RAPID: Coral reef stress responses to an urban fire

Maui’s coral reefs support subsistence, recreational, and commercial fishing, particularly for the large Native Hawaiian population. In August 2023, hurricane winds and low humidity combined with the recent drought to cause an unprecedented fire in Lahaina, an urban coastal town on the island of Maui. The fire quickly burned over 2170 acres and 2200 structures, releasing ash, particulate matter and potentially toxic materials into the adjacent coastal waters. This project provides novel information on the ecological impacts of wildfires to coral reefs to aid in climate change adaptation and emergency response planning. Cultural perspectives and traditional knowledge of Native Hawaiian community members are incorporated throughout the research process. The project directly supports four students, including a Native Hawaiian student, to participate in activities including field work, data collection, analyses and interpretation, and communication of research results. A wildfire in an urban city located adjacent to a coral reef is unprecedented but may become more common as expanding shoreline development intersects with potentially increased fire risk with climate change. The overall objective of this study is to examine the direct effects of urban wildfires and associated potential stressors - such as reduced water quality, acidification, hypoxia, and heavy metals - on coral reef ecosystem function and the potential for regime shifts favoring benthic algae instead of corals. Using the 2023 Lahaina wildfire as a case study, the project employs a “before-after control-impact” design to compare three west Maui reefs both affected and unaffected by wildfire, with special attention to the anticipated remobilization of organic matter, toxic compounds (e.g., polycyclic aromatic hydrocarbons) and metals following rain events in autumn. Physical and chemical water parameters will constrain the reef-scale carbon cycle and coral metabolism before, during and after runoff events to document the ecological responses to urban fire impacts. This project will support three Early Career Researchers, contribute toward research training for multiple graduate and undergraduate students, and provide valuable information about contaminants and water quality to a community that relies heavily on coral reef resources. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.