polyps

Cryopreserving Corals | Earth Wise

October 3, 2023 By EarthWise Leave a Comment

Recent climate models estimate that if the effects of climate change are not mitigated soon enough, 95% of the world’s corals could die by the mid 2030s. Given the current rate of greenhouse gas emissions, this is an increasingly likely outcome. Coral reefs are estimated to have a $10 trillion economic value apart from their essential role in marine ecosystems.

Researchers at the University of Hawaii at Manoa have demonstrated a successful technique for cryopreserving entire coral fragments; in other words, preserving coral using cold temperatures and successfully reviving them.

Existing coral cryopreservation techniques rely on freezing sperm and larvae, which can only be collected during spawning events, which occur only a few days each year for coral species. This makes it logistically very challenging for researchers and conservationists.

The Hawaiian researchers focused on a process called isochoric vitrification, which is a method of freezing with liquid nitrogen that prevents the formation of ice crystals. They tested the technique with thumbnail-sized fragments of coral, freezing them in small aluminum chambers which restrict the growth of ice crystals that would otherwise damage delicate polyp tissues. Once the chambers were warmed, the fragments were transferred to seawater and allowed to recover. They found that the revived corals behaved the same as those that were never cooled.

The process holds great promise to conserve the biodiversity and genetic diversity of coral. If the process can be scaled up, it may be possible to preserve as many species of coral as possible by 2030, when it may no longer be viable for them to survive in the warming and acidifying oceans.

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Cryopreservation breakthrough could save coral reefs

Photo, posted June 2, 2023, courtesy of USFWS – Pacific Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate Resilient Microalgae | Earth Wise

July 21, 2022 By EarthWise Leave a Comment

The plight of the world’s coral reefs has been a growing environmental crisis for many years. Coral reefs provide sustenance and income to half a billion people, are major tourist attractions, protect coastlines, and are important centers of biodiversity. And because of the warming climate as well as other effects of human activity, more than half of the world’s coral reefs are under stress.

The primary threat is coral bleaching, which is the disruption of the symbiotic relationship between coral polyps (which are tiny animals) and the heavily pigmented microalgae that live within the coral structures and provide most of the energy for the polyps. When corals are stressed, often because water temperatures are too high, they expel the microalgae within them. The structures then become transparent, leaving only the white skeletal corals. Bleached corals aren’t dead, but they are at great risk of starvation and disease until and unless new symbiont algae are acquired.

A new study by scientists at Uppsala University in Sweden investigated how different species of coral symbiont algae react to temperature stress. They discovered differences among symbiont cells that enable the prediction of how temperature stress tolerant the cells are. Such predictive ability could provide the means to identify and select more temperature-tolerant coral symbionts that could conceivably be introduced into coral host larvae in order to make corals more robust against climate change.

The research has a ways to go, but the new tools may help coral reef monitoring and increase the speed at which reef restoring efforts can create stocks of climate-resistant symbionts.

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Climate resilient microalgae could help restore coral reefs

Photo, posted September 28, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Artificial Aquatic Polyps | Earth Wise

September 16, 2020 By EarthWise Leave a Comment

Corals are often mistaken for rocks because of their hardened surfaces. And, since they attach or “take root” to the sea floor, they are often mistaken for plants. But unlike rocks, corals are alive. And unlike plants, corals do not make their own food. Corals are actually animals.

Most of these structures that we call “coral” are made up of hundreds to thousands of tiny coral creatures called polyps. A coral polyp, which is often no thicker than a nickel, has a saclike body and mouth that is encircled by stinging tentacles. Polyps are responsible for a host of ecosystem services, including nourishing corals, and aiding coral survival by generating self-made currents through the motion of their soft bodies.

Inspired by these marine organisms, researchers from the University of Warwick in the UK and Eindhoven University of Technology in the Netherlands have collaborated to develop an artificial aquatic polyp capable of removing contaminants from water. The 1 square centimeter wireless robot polyp can attract, grasp, and release objects, moving under the influence of a magnetic field and whose “tentacles” are triggered by light.

The next step for the researchers is to see if the technology can be successfully scaled up from laboratory to pilot scale. In order for that to happen, the team has to design an array of artificial polyps capable of working harmoniously together.

Corals are an incredibly important part of ocean ecosystems. And while it remains to be seen how much value artificial polyps can achieve in future applications, it serves as another example of scientists emulating nature to create more sustainable designs.

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