Some of the coral bleaching that took place more than 90 metres before the ocean surface, in the Central Indian Ocean.

Ocean temperature rise caused coral bleaching at depths over 90m

In November 2019, researchers from University of Plymouth recorded unexpected evidence of coral bleaching more than 90 metres below the ocean surface. 

Describing their discovery as a "huge surprise," Dr Phil Hosegood, Associate Professor in Physical Oceanography at the University of Plymouth and lead on the project, said: "Deeper corals had always been thought of as being resilient to ocean warming, because the waters they inhabit are cooler than at the surface and were believed to remain relatively stable."

A variety of Acropora corals at Lighthouse Reef in Palau where researchers from CSIRO, UQ and PICRC saw rapid coral recovery with the release of dormant coral “seed banks” after a super typhoon in 2012.

Corals store dormant 'seed banks' like forests do

Initially slow, the recovery puzzled scientists in the study, led by marine ecologist Dr Christopher Doropoulos and research co-lead Dr George Roff, together with team members from the University of Queensland and Palau International Coral Reef Center, who expected regeneration to follow traditional patterns, driven by coral spawning events. These events involve the synchronized release of eggs and sperm into the water, leading to the dispersal of coral larvae that settle onto impacted reefs.

Pairs & Companions: Contributors’ Picks

Photo by Anita George-Ares
Photo by Anita George-Ares. Thorny seahorses, Dumaguete, Philippines. Gear: Canon EOS Rebel SL1 camera, Canon EF-S 60mm f/2.8 macro USM lens, Ikelite housing, two Ikelite DS161 strobes. Exposure: ISO 200, f/11, 1/160s

We asked our contributors to share their favorite photos that show pairs and companions, or two of a kind, and they returned with a range of macro to wide-angle shots, featuring a variety of marine life large and small from around the world.