19th Dec 2019
19th Dec 2019
Curated by Dr Shawna Foo
Coral reefs are suffering damage due to climate change and other factors and restoring them is hard and costly. Marine biologists have been 'outplanting' nursery-grown corals for decades. But these are very sensitive to a harsh environment. Remote sensing can help find the best locations where such corals can thrive.
In 10 seconds? How to increase the success rate of complicated coral reef restoration? Scientists suggest the use of technologies that can pinpoint ideal locations from a distance, even from space! (Read the science)
Seriously? Remote sensing for underwater life? Yes! Remote sensing technologies can help marine scientists who spend a lot of time snorkelling and fishing for data about marine reefs. Photography, hyperspectral, infrared imaging and also radar and laser scanning can provide useful details about the physical characteristics of a sea location and information on whether coral fragments planted there were likely to survive. (Read our research paper)
But how is this remote sensing done? Sensors can be mounted on planes, satellites and boats. Each technology can provide different information about the reef, e.g. hyperspectral imaging can provide detail on reef cover, radar scanning can identify differences in water quality and flow regimes and thermal imaging provides information on sea surface temperature. Airborne laser sensors can produce a map of the structural complexity of the reef suggesting an area and depth where corals are less threatened by predator migration. (More on how pigment analysis is used to map habitats)
Are you telling me it was not tried before? Well, not in the specific context of coral restoration. Remote sensing of marine environments is currently limited by various water properties such as depth and turbidity. To improve on this, our team has reviewed and summarized coral reef restoration methods and investigated which remote sensing technologies were the most mature and developed and which of them were the best match for each key restoration step. (Find out more on reef restoration techniques)
And what were the conclusions? That the three key factors when choosing where to outplant nursery-grown corals can all be remotely sensed! These are the existing coral cover, clean substrate and ideal depth. It is important to guide restoration with valuable data as much as possible because even the best reef outplants will fail in a poor location. So, being able to select the optimal site is key to a successful restoration project. (More on the ecological processes that help reef restoration)
And can we expect in the future? Amazingly detailed maps of the seafloor, with data on corals, seagrass, algae, sand and marine species, all acquired from satellites! The tech to distinguish between the different parts of the seafloor and also different coral species is already underway. Our ability to eventually being able to map reefs in detail from satellites will remove the need for time-consuming diver and boat measurements. It will also help our efforts to preserve as many reefs as possible and sustain biodiversity despite continuing climate change. (More on the value of remote sensing in hard-to-reach sites)
Restoration, straight outta the 3D printer
An American research team has come up with an interesting idea to prop up coral populations in the sea: to create artificial ones with the help of a 3D printer.
Initially, they wanted to have a model to study how sea animals hid among the corals and what the ideal shape and complexity was to attract them. In other words, how many branches and of what shapes were needed.
Later they realised that planting complex-shaped artificial corals helped small fish to survive among them.
They also found that fish did not have a problem living around artificial corals printed from biodegradable materials.
These structures help the growth of natural corals over them and eventually dissolve.