Experts are warning that the Great Barrier Reef’s coral reef could suffer mass bleaching in January for the fourth year running.
According to data from the US National Oceanic and Atmospheric Administration, a section of 800 miles of the Great Barrier Reef is likely to undergo a bleaching event by the end of January.
NOAA forecasts also show that by mid-February, areas north of Cairns in Queensland will be at ‘Alert Level 2’ – where both widespread bleaching and significant coral mortality are likely.
Coral bleaching is more likely in warmer months. This is why Australian scientists have been on alert for the Southern Hemisphere summer.
According to scientists, coral bleaching caused the death of 30% of Great Barrier Reef’s corals in 2016. It was followed by its third major bleaching event in 2020.
A mass bleaching event caused coral to become bleached on the Great Barrier Reef, Australia. There have been five major bleaching events on the Great Barrier Reef – 2016, 2017, 2018, 2020 and 1998.
According to US National Oceanic and Atmospheric Administration data (NOAA), Great Barrier Reef may face another massive bleaching event by January.
Rising water temperatures are attributed to human activity, such as burning fossil fuels. Experts believe this is a result of our actions. The warming of the oceans is threatening corals. This leads to coral bleaching as well as acidic water, more disease, and other problems.
Professor Peter Mumby at the University of Queensland told the Guardian that world-famous reef, listed as a World Heritage Site in 1981, is in a critical period for recovery.
But, he stated that NOAA’s forecasts “tends to be quite conservative”, which suggests that the extent of the bleaching events could even be underestimated.
Professor Mumby explained that “everyone feels a little depressed about the prospect of another bleaching incident.”
Dr Selina Ward, also at the University of Queensland, also said: ‘This Noaa forecast suggests we’re likely to have a bleaching event and it would come earlier in the summer than we would expect.’
Scientists believe that a cyclone (or other cool event) will help offset mass bleaching from rising temperatures.
Corals are more stressed by rising ocean temperatures. They release alga that is found in their bodies, which provides them with up to 90% of their energy.
This event causes the vibrantly-coloured communities of coral to turn white – an effect called coral bleaching.
It is believed that coral bleaching, as seen here on the Great Barrier Reef, was caused by heat stress from warmer water temperatures due to global climate change.
While corals do not die, bleached corals have a greater chance of dying. Climate change is making these events more common.
Although some coral reefs may be capable of recovering over time, other coral reefs become overwhelmed by seaweed.
If coral receives its nutrients quickly enough, they can survive bleaching. However, if this is not the case, it could cause death in a matter of days as previous research has shown.
Over the years repeated coral bleaching caused by warming oceans has led to disruption of marine ecosystems throughout the world.
This decreases the food supply and shelter available for many of the marine species dependent on coral structures. It also results in biodiversity declines.
Fortunately, Australia’s climate is currently under the influence of La Niña – the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean.
This is expected to deliver more cloud and rain to the reef’s waters, which would cool temperatures and potentially avoid a bleaching event.
‘But we have just not seen that yet this summer,’ Dr David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, told the Guardian.
‘We’re hoping those typical La Niña conditions will kick in. It is crucial to monitor the weather over the coming weeks.
Australian scientists reported that the Great Barrier Reef experienced its third major bleaching event within five years during the 2019-20 Southern Hemisphere Summer.
1.036 Reefs have been surveyed from the air. It was found that they were badly affected in their northern, central, and southern regions.
The ARC Centre of Excellence previously calculated that coral bleaching had affected the Great Barrier Reef’s southern third.
French Polynesia’s bleached coral was seen during the 2019 bleaching. It is thought that this may have been due to heat stress as a result to higher water temperatures in response to global climate change.
Air surveys revealed the northern, central and southern areas had been hit by coral bleaching during the 2019-20 Southern Hemisphere summer
One promising development to reduce bleaching has been scientific attempts to transplant live corals grown in the lab to dying reefs in the ocean.
The new corals from the lab are expected to boost reef recovery and restore it to its healthy condition.
However, these transplanted corals often face low survival rates due to poor planning and site selection based on convenience, according to University of Hawaii Manoa researchers.
To lure fish into the damaged coral areas, loudspeakers have been used to make ambient sounds from a healthy reef.