Prehistoric Coral Reefs Roamed Much Further From Equator, Study Finds
New research has revealed that coral reefs existed way beyond today’s tropical zones up to 250 million years ago. Ancient reefs stretched much further from the equator, thanks to warmer climates and shifting continents.
Corals Tracked Climate Over 250 Million Years
A team from the University of Vigo, University of Bristol, and University College London combined fossil evidence with habitat modelling to map coral reef locations through deep time. Their findings, published in Nature Communications, show that corals thrived in warm tropical to subtropical conditions but pushed poleward during global warming phases.
“Tropical-to-subtropical climatic conditions are tracked by warm-water coral reefs over geological timescales,” said Dr Lewis Jones, computational palaeobiologist at the University of Vigo. “During colder periods, reefs retreated closer to the equator.”
Global Cooling Forced Coral Retreat 35 Million Years Ago
The study highlights a major shift 35 million years ago. Global temperatures plunged and tectonic shifts in the Indo-Australian Archipelago blocked reef expansion, confining coral habitats mostly to tropical waters.
These “sea rainforests” – home to the planet’s richest marine biodiversity – now cling to areas where ocean temperatures rarely dip below 18°C.
Can Modern Corals Keep Up With Rapid Climate Change?
While warm climates once allowed corals to spread widely, the team warns the current, rapid pace of human-driven climate change may outstrip the reefs’ ability to adapt.
“Some tropical reef corals are already growing in size, but the question remains if coral ecosystems and their wildlife can keep up with today’s unprecedented speed of change,” said Dr Jones.
The researchers stress that cutting global warming is critical to saving coral reefs and their rich biodiversity.
New Approach Sheds Light on Coral Evolution
Until now, fossil gaps and biased records made it tough to pin down how climate influenced coral reef distribution. Most fossil reef data came from wealthy countries, skewing understanding.
Dr Alex Farnsworth from University of Bristol said, “With this combined data-model method, we can finally grasp coral reef evolution and how climate shaped their past.”
Professor Dan Lunt, also from Bristol, added, “This study proves climate and reefs have been tightly linked through Earth’s history – a big red flag for today’s warming seas.”
