Scientists conducted a new research which shows that the rising temperatures induce stress on coral reefs ranging from 30-150 meteres (mesophotic zone) from sea-surface. Earlier, researchers used sea-surface temperature data collceted through satellites to foretell the temperature-driven stress on corals. New research shows that the sea-surface temperature alone, could not accurately predict the thermal stress on the corals.
Deeper corals are believed to be safer from ocean-warming than their shallow-counterparts. The researchers studied two decades of data sets of sea level, sea-surface temperature and temperature differences between surface and mesophotic zone, to develop a forecast tool to understand how corals are affected by rising temperatures.
PhD candidate Travis Schramek, lead author of the study said, as quoted by ANI, "We're now adding the dimension of depth into the problem where before we were only skimming the surface of what temperature stress meant for corals. We see that the heat-induced stress penetrates all the way into the mesophotic zone during larger bleaching events."
Scientists used a network of reef temperature recorders maintained by CRRF divers in important locations across Palau, the recorders were set deep till the depth of 90 meters (295feet). A team of divers conducted weekly dives for 20 years to monitor the changes along the reefs, as a part of temperature-monitoring program. Deeper zones are showing bleaching coincident with the higher temperature, along with the shallow reefs, observation reveals.
Travis Schramek combined the sea level and surface temperature recordings and found that the height of ocean water-level strongly indicates the change in temperature in the deeper levels. Schramek with the team, further used this data to predict the temperature in the shallow coral reefs and deeper reefs as well.
"A surprising outcome of the study is that the oceanic conditions along the dramatic reef walls that are the boundaries of Palau are very representative of the broader Western Pacific," said Eric Terrill, an oceanographer as quoted by ANI.
Schramek believes that the the research can now be used to predict the fluctuations in temperature and its consequences on the coral reefs. He added that "If we can better understand how they're stressed, then we can better understand how to protect them," as quoted by ANI.
The findings were published in the Journal of Geophysical Research Letters. The research team says that with new insights they can predict thermal stress and can better understanding of the coral reef system, this could help them build a conservation policy to protect the diverse and valuable ecosystem.