Extreme and marginal coral reefs and communities: A global synthesis
Author Identifier (ORCID)
Abstract
Corals are foundation organisms that thrive in a wide range of environmental conditions. While much of the research on tropical coral reefs has focused on areas conducive to carbonate growth, such as clear, low-nutrient, shallow waters, there is a significant gap in studying coral communities and reefs that thrive at the edge of their environmental limits. Recent theoretical advancements have provided a novel framework for studying these extreme and marginal reefs, re-defining coral reef extremeness and marginality and providing a broader perspective on their ecological significance. Extreme coral environments are characterised by large deviations from optimal abiotic conditions, with extreme in this case meaning: elevated siliciclastic sedimentation, turbid waters, high nutrient levels (e.g., nitrogen and phosphorus), substantial depths, and fluctuating or extreme temperature, pH, salinity, and dissolved oxygen conditions. In some cases, but certainly not all, these extreme conditions can lead to altered coral cover, community composition, and ecosystem functioning characteristic of marginal reefs and coral communities. Thus, areas with extreme environmental conditions are often mistakenly considered unsuitable for sustaining biogenic growth and biodiversity. However, extreme environments may serve as refugia and natural laboratories in the face of ongoing climate change, and can potentially offer insights into how coral ecosystems might respond to future oceanic conditions. This chapter serves as a comprehensive introduction to the global study of extreme and marginal reef environments, consolidating the knowledge accumulated to date. It provides an overview of the unique coral communities found in extreme conditions, such as those in the hottest waters, turbid-zone reefs, intertidal zones, low pH areas around submarine springs and CO2 vents, regions affected by upwelling and internal waves, as well as seagrass and mangrove-coral ecosystems, semi-enclosed bays, mesophotic reefs, and high-latitude reefs. Given the increasing impacts of climate change and human activities on global coral reefs, research into these important habitats offers critical insights for conservation and the future resilience of marine ecosystems.
Keywords
climate change, cold-water communities, high-latitude reefs, hot-reefs, Intertidal and back-reef coral environments, low pH habitats, mangroves, mesophotic reefs, reef-building corals, seagrasses, semi-enclosed bays, turbid-zone reefs, upwelling
Document Type
Book Chapter
Date of Publication
1-1-2026
E-ISSN
22137203
ISSN
2213719X
Volume
24
Publication Title
Extreme and Marginal Coral Reefs and Communities
Publisher
Springer
School
Centre for Marine Ecosystems Research / School of Science
Copyright
subscription content
First Page
1
Last Page
15
Recommended Citation
Soares, M. O., Smith, T. B., Camp, E. F., & Schoepf, V. (2026). Extreme and marginal coral reefs and communities: A global synthesis. In M. O. Soares, T. B. Smith, E. F. Camp, & V. Schoepf (Eds.), Extreme and marginal coral reefs and communities (pp. 1–15). Springer. https://doi.org/10.1007/978-3-032-28035-0_1