What are coral reefs?
Bursting with life, coral reefs are natural flood defences, biodiversity hotspots, spawning grounds for juvenile fish, sources of medicines and also a lifeline for the economic livelihood and food supply of millions of people around the world. These beautiful ecosystems made from thin layers of calcium carbonate are found in the oceans around the tropics of Cancer and Capricorn.
However, these sites are becoming increasingly endangered by today’s society and changing climate. Loss of coral reefs threatens not only the quarter of our planet’s marine species supported by coral reefs, but also the human populations who rely on these areas for jobs and food. Most coral reefs have been thriving under the sea for the last 5000 – 10,000 years, but are recently coming under threat. In many locations they have even been lost already. Tragically, the future could pose complete extinction and a subsequent drop in biodiversity. The variety of species who call coral reefs their home is currently greater than can be found in any other shallow-water marine environment, and such species could be lost with certain climate change scenarios.
Why are coral reefs endangered?
Corals are very sensitive and fragile environments. When water temperatures rise too high, the corals can no longer survive – a process known as coral bleaching due to the shade of white they become. Climate change has already seen coral bleaching rates increase and as temperatures rise, this alarming trend is only set to worsen.
Although coral bleaching is the main and most publicised threat, ocean acidification, overfishing, unsustainable coastal development, pollution, tourism and coral mining all also play a role in the destruction of these fragile environments. Increasing greenhouse gas emissions are responsible for temperature rise and ocean acidification, but even if these are reduced, the other threats still remain.
With so many opportunities for harm and such consequences of their loss, it is imperative to protect these dynamic ecosystems. Just a few weeks ago (14th Oct 2020) a report was released showing the damage to the Great Barrier reef of extensive coral bleaching in 2016 and 2017, killing half of the corals.
So is there any good news?
Yes! About half of the world’s shallow water coral reefs have already disappeared, but the discovery of a new deep water reef off the northern coast of Australia this week is making waves in scientific discussions. This latest reef is a mesophotic reef (found below 30 metres). Because it’s deeper and further from the shore, the reef is less susceptible to the threats of bleaching, fishing pressure and land-based pollution. Such deep reefs are still degrading, but at a slower rate than their shallow-water counterparts. Exploration at these depths has only become possible relatively recently, and so there is scope (and hope) for more discoveries of this kind.
Uncovered as part of a 12 month mapping project of Australia’s oceans, this 500m tall coral reef is located about 60 miles off the Cape York Peninsula, a wilderness area of northern Australia. At 1.5 km long and 40m below the surface at its peak, estimates suggest this beauty could be up to 20 million years old. The detached reef is not part of the Great Barrier Reef, but sits instead among 7 other reefs which were discovered in the late 1800s.
The “new” reef differs from its neighbours, however. Excitingly, the ecosystem appears to be more vibrant, with early investigations suggesting a thriving population of both fish and sharks, such as tiny hatchetfish, silvertip, and grey reef sharks. The upper section doesn’t seem to contain many hard corals, but it does have an array of sponges, sea fans and soft corals, indicating the circulation of nutrient rich water.
The discovery was made by the Schmidt Ocean Institute, using an underwater robot called “SuBastian”. This remote controlled device can collect samples and images to then be identified by the scientists. The team have said that this process will take a long time however, so it’s yet to be seen if any new species have been found. The project has already discovered several new species and what is believed to be the longest recorded sea creature, giving just a glimpse of the richness of the biodiversity of our oceans.
This really is the good news we all needed. And this is just one report of many. Although perhaps this one coral reef is a relatively small contribution – a drop in the ocean even – it’s a bit of positive news we could all do with right now.
So why does this matter?
This exciting new discovery leaves us thinking – what else lies in our oceans waiting to be uncovered? The principal investigator of the expedition, Tom Clarke, said “we know more about the surface of the moon than we know about what lies in the depths beyond our coastlines”.
It just goes to show how little we know about our planet, and leaves an eager anticipation for future discoveries of a similar nature. The new technologies provided by the not-for-profit Schmidt Ocean Institute have the potential to bring a tidal wave of new research and information about our oceans, ultimately providing decision makers with the necessary tools to protect biodiversity, and more specifically coral reefs.
As a fierce optimist, I see the discovery of this reef as the first step in a new technologically advanced era in which we are more aware of the world beneath the ocean surface.