Cellular mapping of coral could help save reefs — new study

Over half a billion people depend on coral reefs for food, income, and protection, but climate change and pollution threaten to decimate coral populations.

Coral (photo credit: HAGAI NATIV.)
(photo credit: HAGAI NATIV.)
The genetic profile of each cell in stony corals has been mapped for the first time in a new study published by the journal Cell.  
The study was conducted by the University of Haifa, the Centre for Genomic Regulation in Barcelona, and the Weizmann Institute. This groundbreaking research can help identify certain biological processes in the coral, which can shed light on how best to protect dying coral reefs.
Coral reefs are considered the "rainforests" of the sea, in that they house 25% of marine animals, providing them with food, oxygen, and shelter, according to the National Oceanic and Atmospheric Administration (NOAA).
“The size of the coral reefs puts the photosynthetic process on a similar scale to that of the rainforests”, the researchers in the study explained.
It's not just animals that benefit from the coral reefs though. Their immobile structure protects coasts from storms and erosion, they provide countries with tourist and fishing industries,  and can even be used in pharmaceuticals. At least half a billion people depend on the reefs, the NOAA reported.
Unfortunately, due to pollution, overfishing, sedimentation, eutrophication, and rising temperatures, which increase ocean acidification, coral reefs are in grave danger. 
Specifically in the Gulf of Eilat, oil and fuel spills, wastewater, irresponsible mariculture, and tourist infringement have threatened to destroy the coral reef populations, an essay on The Coral Reefs of Eilat — Past, Present and Future by Prof. Joseph Loya of the Tel Aviv University's Life Sciences department argued. "Our reefs are dying at an alarmingly fast rate," Loya warned. 
"The warming of seawater and rising acidity pose a threat to the future of coral reefs," Dr. Tali Mass, the author of the study on the coral's gene atlas and the head of the Coral Biomineralization and Physiology Laboratory at the University of Haifa worried as well.
"The genetic sequencing we have completed is extremely important for the survival of coral reefs and the future of the oceans,” she added.
Using single-cell RNA sequencing, the research team managed to map 40 cell types in the coral throughout its life cycle, from mobile larvae to stationary reefs. The study identified cells responsible for the coral's skeletal formation, symbiosis with algae, immune, and digestive systems, even showing similarities in its immune system transcription factors with those of mammals. 
"Understanding the cellular structure will help us to understand the biological processes that permit the existence of the coral reef,” University of Haifa's Dr. Shani Levy, who led the study, said.
The data and findings of the project offer a promising future in developing treatments for sick coral, better comprehending what factors lead to coral resistance in rising temperatures and ocean acidification, and potentially modifying their genetic code to decrease susceptibility. 
Some 50% of the world's coral reefs have faced severe damage, Zalul, an organization dedicated to preserving Israel's seas and rivers, published in 2018. Yet, the Red Sea coral reefs have proved more resistant to pollution and disease, it noted. Understanding the genetic makeup and what causes the coral species to withstand environmental threats may be the key to rehabilitating reefs across the world.