In Reefs of Time, geoscientist and science educator Lisa S. Gardiner offers a compelling and accessible exploration of how fossil coral reefs can inform our understanding of the threats facing reefs today.
Drawing on research across geology, palaeontology, marine biology and climate science, the book connects the long history of coral evolution and extinction with the urgent challenges of the Anthropocene—climate change, ocean acidification, sea-level rise and habitat degradation.
Gardiner’s narrative centres on fossil reefs of the Caribbean, many of which she has studied firsthand. Through a mix of field observations and scientific synthesis, she reconstructs ancient reef ecosystems and reveals how they responded to past periods of environmental upheaval. The result is a deep-time perspective that reshapes how we interpret present-day reef decline.
Resilient and vulnerable
A key message of the book is that coral reefs are both resilient and vulnerable. Fossil records show that reefs have endured repeated climate shocks and extinctions—but only when certain thresholds were not exceeded. Past collapses were often driven by multiple interacting stressors, much like the compound threats coral reefs face today. By recognising these patterns, scientists and conservationists can better identify tipping points and prioritise interventions.
Refugia
Gardiner also highlights the importance of refugia—areas where corals survived during extreme past conditions. Identifying similar modern refuges could prove vital for safeguarding biodiversity. Likewise, understanding which coral species thrived after ancient disturbances can guide present-day restoration, breeding and reef management strategies.
Throughout, Gardiner argues that recovery from reef decline is measured not in years or decades but in millennia. This underscores the urgency of current conservation efforts: waiting for natural recovery is not an option. Instead, protecting genetic diversity, reducing local stressors and using palaeoecological insight to inform restoration are essential steps.
Grounded perspective
Reefs of Time ultimately reframes the fossil record not as a static archive, but as a vital tool for anticipating future scenarios and guiding human action. As coral reefs continue to face unprecedented pressure, this book offers a timely and scientifically grounded perspective on what it will take—not just to understand reef loss, but to promote their survival.
