There is concern that consecutive cyclones may have caused harm to the Great Barrier Reef.
Experts are worried that two consecutive cyclones passing over the Great Barrier Reef may have caused significant damage to the largest coral reef system in the world, due to extensive flood plumes and strong waves.
Marine researchers and environmentalists entered the summer season with concerns that an El Niño weather phenomenon could increase the likelihood of widespread coral bleaching.
However, the most significant worries thus far have arisen from Cyclone Jasper in December and Cyclone Kirrily last week. These cyclones have resulted in river catchments releasing large amounts of freshwater containing sediments and nutrients.
The concerns arise shortly before the federal government’s 1 February due date to submit a report on its efforts to safeguard the reef to Unesco, in order to prevent it from being added to the list of endangered world heritage sites.
Clean water can lead to coral bleaching and cloudy water can deprive reefs and seagrass meadows of light, encouraging algae growth. This can make it more challenging for corals to thrive and reproduce.
Cyclones can create powerful waves that have the potential to harm coral reefs and disrupt seagrass meadows, which are important ecosystems for dugongs, turtles, and young fish.
Although cyclones typically have a cooling effect on waters, the Great Barrier Reef Marine Park Authority (GBRMPA) stated to the Guardian that sea surface temperatures in the reef area were still at least 1 degree Celsius higher than the average.
According to Dr. Jane Waterhouse, a scientist specializing in water quality at TropWater research group at James Cook University, it seems that there is no respite for the reef.
She expressed worry about the possible consequences of the run-off on the reefs in the northern regions.
According to her, marine ecosystems have an aversion to freshwater and there have been reports of freshwater bleaching occurring this season.
TropWater examined satellite pictures in the latter part of December and discovered that the outflow from rivers, caused by heavy rainfall brought on by Cyclone Jasper, had spread beyond the reefs near the coast.
Dr. Stephen Lewis, a specialist in water quality at TropWater, noted that Cyclone Jasper struck towards the end of the sugar cane harvesting season, when fields had recently been treated with chemicals and pesticides.
He stated that the timing of the event increased the likelihood of nutrients entering the reef. However, he also acknowledged that there was limited action farmers could have taken to prevent this from happening. It is currently too soon to determine the impact of flood plumes caused by Cyclone Kirrily.
However, Lewis noted that there is a significant lack of research in flood monitoring, as water samples are only collected from reefs close to shore.
He suggested expanding water monitoring to gain a better understanding of how land-based runoff impacts reefs located further offshore.
According to Waterhouse, it is possible that a different trend may be developing due to the effects of climate change. This trend involves coral bleaching occurring alongside heavy rainfall, which limits the opportunity for recovery.
According to Dr. Roger Beeden, the lead scientist of GBRMPA, there has been a significant influx of water which may have negative effects not only on corals.
Initial observations from surveillance indicated that the effects of Cyclone Jasper on coral may not have been as severe as anticipated. He stated that there were only sporadic accounts of bleaching.
However, he did mention that there are still ongoing pressures for the remainder of the summer.
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Although cyclones may harm coral reefs and create flood plumes, they can also have a positive impact by lowering ocean temperatures and decreasing the likelihood of coral bleaching.
However, according to the US National Oceanic and Atmospheric Administration’s (NOAA) Coral Reef Watch, certain reef areas closer to the shore experienced significant heat stress on Monday, resulting in bleaching.
According to Beeden, the forecasts from the Bureau of Meteorology and the NOAA indicate that the conditions on the reef will continue to be warm for the next few months.
“We will not witness the same level of consequences from the consecutive mass bleaching events in 2016 and 2017; however, the combined effects are worrisome for the coral’s ability to thrive and reproduce.”
The government must submit a progress report to Unesco by Thursday regarding their reef conservation efforts. They made a commitment last year to improve water quality and align climate targets with the goal of limiting global warming to 1.5C.
According to Richard Leck, the leader of WWF Australia’s Ocean division, it is crucial for Queensland and the federal government to ramp up their actions regarding catchment management, particularly in regards to deforestation, in response to the significant flood plumes currently being observed.
“Illegal clearance of approximately 100,000 hectares around the reef takes place annually, highlighting the inadequacy of current laws.”
According to Leck, the Queensland government can now declare their updated state climate goals, which were revealed in December, to reduce emissions by 75% from 2005 levels by 2035.
He stated that it is challenging to decarbonize Queensland due to its heavy industry. However, if Queensland can make commitments in this regard, then as a country, we should be able to meet them.