Extreme and Marginal Coral Reefs and Communities : Living at the Edge of Environmental Limits

Coral reefs are among the most productive and biodiverse marine ecosystems on Earth, often referred to as the “tropical rainforests” of the sea. They provide essential ecosystem goods and services that support the livelihoods of nearly 1 billion people worldwide through fisheries, tourism, and coastal protection. While most research has traditionally focused on reefs existing in optimal environmental conditions—clear, shallow, and nutrient-poor waters—this book expands the scope by addressing a less explored but increasingly important topic: coral reefs and communities that persist at the edge of their environmental limits. This novel volume offers a comprehensive synthesis of current knowledge (e.g., geology, ecology, ecosystem services) on reefs found in environments once considered unsuitable for coral growth, including - but not limited to - turbid waters, high-nutrient systems, mesophotic depths, and areas with fluctuating temperature, pH, and oxygen levels. Drawing on examples stretching the world’s coral reefs such as the Indo-Pacific, Caribbean, South Atlantic, Red Sea, and Persian/Arabian Gulf, this book examines how these unique systems function, how they differ from traditional reefs, and what their potential is as natural laboratories for understanding reef resilience in a changing ocean. It highlights emerging evidence that some extreme reefs may act as refugia or resilience hotspots in the face of global climate change, while also acknowledging ongoing scientific debates and knowledge gaps that require further investigation. Targeted at researchers, graduate students, environmental managers, and policymakers, this first book about this important topic provides a critical resource for advancing both scientific understanding and evidence-based decision-making. By systematically compiling and analyzing dispersed research, it offers a foundation for developing more effective science-based conservation and climate adaptation strategies.