New studies reveal novel advances in understanding the evolutionary history of hard corals. It showcases their incredible potential to be a solution to climate change. Conducted by Claudia Vaga and her team, the study sequenced genomes from 274 species of stony corals, representing nearly 16% of all currently living species. A new report released today in the journal Nature has revealed this ancient lineage of these crucial, gateway marine organisms. These findings highlight just how vulnerable they are in our rapidly changing world.
Some 460 million years ago, stony corals, or Scleractinia, started showing up on the geologic record. They probably evolved from a shared ancestor that was a heterotrophic eukaryote. This ancestor could not photosynthetically produce its own food and lived in both shallow and deep water environments. Knowing this family tree is so important. It shows us how these organisms have weathered a litany of environmental changes throughout their prehistoric lives.
Stony corals, a group of marine organisms that include coral reef builders, act as keystone species, forming important habitat and structure for myriad marine life. They are under enormous threat due to the effects of global climate change, which has drastically changed their habitats. With growing threats to coral reefs and their long-term survival, understanding trends in their health is crucial.
Evolutionary Insights
The molecular study by Vaga and coworkers was most focused on reconstructing the evolutionary tree of the order Scleractinia (stony corals). In an effort to fill in the gaps of evolutionary relationships between different stony corals, researchers evaluated genetic data from the sampled coral species. According to this new analysis, all of these coral species are descendants of a common ancestor that lived half a billion years ago.
Fossil records indicate that many of these symbiotic, reef-building coral species suffered severe mortality. They almost went extinct during the big ocean anoxic event about 180 million years ago. These occurrences underscore the susceptibility of corals to anthropogenic environmental change. The research indicates that coral diversification did not significantly progress until after two additional anoxic events between 120 and 90 million years ago.
Some 300 million years ago, a dynamic relationship developed between corals and photosynthetic algae. This input joint stability and movement led to a tremendous diversification of corals. This collaboration with zooxanthellae enabled corals to absorb energy from sunlight, enhancing their resilience and survival across a wide range of ocean habitats.
The Threat of Climate Change
Stony corals have been remarkably resilient in the face of other historic environmental crises. Today they are ideologically being threatened with execution on the altar of climate change. Rising ocean temperatures, increased acidity, and pollution have led to widespread coral bleaching events, which compromise their health and survival. As these vital organisms struggle to adapt to rapidly changing conditions, researchers emphasize the importance of understanding their evolutionary history to aid conservation efforts.
The rocky features are extremely biodiverse, with more than 274 species of stony coral found in the region. A lot of extant species were absent from this genomic comparison. Further studies can offer more pieces to the puzzle about their genetic diversity and possible resilience-building factors.
Implications for Conservation
The results of Vaga’s study carry important implications for coral conservation efforts. By inferring stony corals’ pedigree or evolutionary history from their genetic blueprint, scientists can decipher the code to resilient traits. Understanding these mechanisms can increase our corals’ resilience against climate change. All of this information is critical in developing strategies to protect coral reefs and the biodiversity they support.