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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Coral reef | 12/13 | https://en.wikipedia.org/wiki/Coral_reef | reference | science, encyclopedia | 2026-05-05T07:34:41.179437+00:00 | kb-cron |
=== Heat-tolerant symbionts === Another possibility for coral restoration is gene therapy: inoculating coral with genetically modified bacteria, or naturally occurring heat-tolerant varieties of coral symbiotes, may make it possible to grow corals that are more resistant to climate change and other threats. Warming oceans are forcing corals to adapt to unprecedented temperatures. Those that do not have a tolerance for the elevated temperatures experience coral bleaching and eventually mortality. There is already research aimed at creating genetically modified corals that can withstand a warming ocean. Madeleine J. H. van Oppen, James K. Oliver, Hollie M. Putnam, and Ruth D. Gates described four levels of human intervention for genetically modifying corals, each increasing in intensity. These methods focus on altering the genetics of the zooxanthellae within coral rather than the alternative. The first method is to induce acclimatization of the first generation of corals. The idea is that when adult and offspring corals are exposed to stressors, the zooxanthellae will gain a mutation. This method is based primarily on the chance that the zooxanthellae will acquire the specific trait that will enable them to better survive in warmer waters. The second method focuses on identifying the different kinds of zooxanthellae within the coral and on determining how many of each live within the coral at a given age. Use of zooxanthellae from the previous method would only boost success rates for this method. However, this method would only apply to younger corals for now, because previous experiments manipulating zooxanthellae communities at later life stages have all failed. The third method focuses on selective breeding tactics. Once selected, corals would be reared and exposed to simulated stressors in a laboratory. The last method is to genetically modify the zooxanthellae themselves. When preferred mutations are acquired, the genetically modified zooxanthellae will be introduced to an aposymbiotic polyp, and a new coral will be produced. This method is the most labor-intensive of the fourth, but researchers believe it should be used more and holds the most significant promise for genetic engineering in coral restoration.
=== Invasive algae === Hawaiian coral reefs smothered by the spread of invasive algae were managed with a two-pronged approach: divers manually removed invasive algae, with support from super-sucker barges. Grazing pressure on invasive algae needed to be increased to prevent regrowth. Researchers found that native collector urchins were a reasonable candidate for algae biocontrol to extirpate the remaining invasive algae from the reef.
==== Invasive algae in Caribbean reefs ====
Macroalgae, or seaweed, have the potential to cause reef collapse because they can outcompete many coral species. Macroalgae can overgrow corals, shade them, block recruitment, release biochemicals that can hinder spawning, and potentially form bacteria harmful to corals. Historically, algae growth was controlled by herbivorous fish and sea urchins. Parrotfish are a prime example of reef caretakers. Consequently, these two species can be considered keystone species in reef environments due to their role in protecting reefs. Before the 1980s, Jamaica's reefs were thriving and well cared for; however, this all changed after Hurricane Allen occurred in 1980 and an unknown disease spread across the Caribbean. In the wake of these events, massive damage was caused to both the reefs and the sea urchin population across Jamaican reefs and into the Caribbean Sea. As little as 2% of the original sea urchin population survived the disease. Primary macroalgae succeeded the destroyed reefs, and eventually larger, more resilient macroalgae soon took their place as the dominant organism. Parrotfish and other herbivorous fish were few in numbers because of decades of overfishing and bycatch at the time. Historically, the Jamaican coast had 90% coral cover and was reduced to 5% in the 1990s. Eventually, corals were able to recover in areas where sea urchin populations were increasing. Sea urchins fed, multiplied, and cleared substrates, leaving areas for coral polyps to anchor and mature. However, sea urchin populations are still not recovering as fast as researchers predicted, despite being highly fecund. It is unknown whether or not the mysterious disease is still present and preventing sea urchin populations from rebounding. Regardless, these areas are slowly recovering with the aid of sea urchin grazing. This event supports an early restoration idea of cultivating and releasing sea urchins into reefs to prevent algal overgrowth.
=== Microfragmentation and fusion === In 2014, Christopher Page, Erinn Muller, and David Vaughan from the International Center for Coral Reef Research & Restoration at Mote Marine Laboratory in Summerland Key, Florida developed a new technology called "microfragmentation", in which they use a specialized diamond band saw to cut corals into 1 cm2 fragments instead of 6 cm2 to advance the growth of brain, boulder, and star corals. Corals Orbicella faveolata and Montastraea cavernosa were outplanted off the Florida's shores in several microfragment arrays. After two years, O. faveolata had grown 6.5x its original size while M. cavernosa had grown nearly twice its size. Under conventional means, both corals would have required decades to reach the same size. It is suspected that if predation events had not occurred near the beginning of the experiment O. faveolata would have grown at least ten times its original size. By using this method, Mote Marine Laboratory successfully generated 25,000 corals within a single year, subsequently transplanting 10,000 of them into the Florida Keys. Shortly after, they discovered that these microfragments fused with other microfragments from the same parent coral. Typically, corals that are not from the same parent fight and kill nearby corals in an attempt to survive and expand. This new technology, known as "fusion," has been shown to grow coral heads in just 2 years, rather than the typical 25–75 years. After fusion occurs, the reef will act as a single organism rather than several independent reefs. Currently, no published research has been conducted on this method.
== See also ==