How does temperature affect the Great Barrier Reef?
When corals suffer heat stress, they expel the microscopic algae that live inside their tissues, revealing their white skeletons. Already marine heatwaves have triggered three mass coral bleaching events on the Great Barrier Reef in just five years, reducing shallow water coral reefs by as much as 50%.
How much of a temperature change above average does it take for coral bleaching?
Coral bleaching is caused by the breakdown of this relationship. The leading cause of coral bleaching is rising water temperatures. A temperature about 1 °C (or 2 °F) above average can cause bleaching.
How are Degree Heating Weeks calculated?
Degree Heating Week (DHW) shows how much heat stress has accumulated in an area over the past 12 weeks (3 months) by adding up any temperature exceeding the bleaching threshold during that time period. When DHW reaches 4°C-weeks (7.2°F-weeks), significant coral bleaching is likely, especially in more sensitive species.
What is ocean temperature change?
As the oceans absorb more heat, sea surface temperature increases, and the ocean circulation patterns that transport warm and cold water around the globe change. Increases in sea surface temperature have led to an increase in the amount of atmospheric water vapor over the oceans.
What is the average temperature of coral reefs?
between 73° and 84° Fahrenheit
Warm Water Most hard corals prefer water temperatures that range between 73° and 84° Fahrenheit (23° and 29° Celsius), though some can tolerate temperatures as low as 68° F (20° C) and as high as 90° F (32° C).
How do Increased temperatures cause coral bleaching?
Warmer water temperatures can result in coral bleaching. When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching.
Is the Great Barrier Reef warm or cold?
Spirit of Freedom operates in the northern sector of the Great Barrier Reef, a tropical zone with relatively warm temperate winters and high humidity in the summers. Water temperatures range 24°C/75°F in the winter, peaking at 30°C/ 86°F in the summer, while maximum air temperatures will range 24°C/75°F to 32°C/90°F.
How is the DHW value determined?
DHW is computed as the accumulation of positive temperature anomalies (HotSpot) above a hypothesised coral bleaching stress temperature (i.e., 1 ◦C above the maximum of monthly means SST climatology—MMM) over the previous 12 weeks [18,19].
What is the temperature threshold for coral bleaching?
The HotSpot value of 1.0 °C is a threshold for heat stress leading to coral bleaching. To highlight this threshold, HotSpot values below 1.0 °C are shown in purple, and HotSpots of 1.0 °C or greater range from yellow to red.
What’s the average water temperature of the Great Barrier Reef?
Great Barrier Reef is a city close to pacific ocean. February is the month with the highest water temperature at 84.2°F / 29°C. The coldest month is July with an average water temperature of 73.6°F / 23.1°C. September is the driest at 0.1in / 3.3mm and February the wettest month with 13.3in / 337.2mm.
When does the Great Barrier Reef turn 150 years old?
Come November and December this year (2021) it will be exactly 150 years since a scientific expedition made meticulous observations of water temperatures along the Great Barrier Reef.
Where does the Great Barrier Reef take place?
Water Temperature Great Barrier Reef. The Great Barrier Reef lies off the coast of Queensland, Australia in the appropriately named Coral Sea area of the Pacific Ocean. The reef is considered one of the seven natural wonders of the world. It’s the largest living structure on the globe, and can even be seen from outer space.
Why did the Great Barrier Reef bleach in 2015?
Sea temperature increases and coral stress from other impacts increase corals’ vulnerability to bleaching. In 2015, the northern section of the Great Barrier Reef experienced large scale bleaching; a stress response to higher than average water temperatures.