The Reef in OUR Hands

Photo submission brief
Submissions should highlight the dynamic relationship between humans and coral reefs, the threats and pressures that they face today and into the future. Judges will be looking for originality and artistic vision. NB: Extensive image manipulation is permissible in this category. See rule 4.

If you are a member and would like to enter a photograph in this category Login Here and click on the "Photography Competition" link in the members section. If you are not a member and you would like to join Click Here to register as a new member.

Why did we select this category?
With increasing human impacts along with a worrying trend in climate change our coral reefs are increasingly under threat. The Reef is in OUR hands because we do have the power to reduce these impacts and move towards a more sustainable future.

How does Global Climate Change affect coral reefs?
Sadly the future of our coral reefs is seriously at risk from climate change. The issues corals face include:

• Coral bleaching
• Ocean acidification
• Sea level rise
• Coral disease

Coral bleaching
Reef-building corals build limestone skeletons which form coral reefs… so coral reefs wouldn’t exist if it wasn’t for the reef-building corals! These corals contain tiny algae in their tissues called zooxanthellae. The zooxanthellae provide their coral host with oxygen and food and receive nutrients and shelter in return. The zooxanthellae are also responsible for the greeny-brown colours in corals.

This relationship can break down when summer sea surface temperatures rise by just a few degrees celsius and the zooxanthellae are expelled leaving a white or fluorescent-looking coral behind. Corals can become less healthy or die with prolonged bleaching because their access to oxygen and food is reduced.

The Great Barrier Reef has been affected by 2 serious mass bleaching events since 1998. Scientists predict these events will become more frequent and more severe with global warming.

Imagine if you didn’t eat for 2 weeks, you would be weaker and more susceptible to getting sick! Likewise, corals that appear to have recovered from bleaching (by taking in new zooxanthellae and recovering their normal colour) may also be less able to recover from other impacts such as water quality pollution and overfishing. So by reducing the coral’s health we are reducing its ability to recover (i.e. its resilience) from other harmful impacts.

How do you identify a bleached coral? Coral bleaching can be either partial, meaning that only the upper surface of the coral is affected, or in more extreme cases, the whole coral can bleach. Some corals contain fluorescent pigments, which are believed to help to protect the coral from bleaching. When these corals do bleach, however, they look fluorescent instead of white.

Illustration by Sarah Lowe (hyperlink sarah@earthwrite.com.au)

Ocean acidification
The oceans absorb carbon dioxide (CO2) from the atmosphere. Scientists estimate that the oceans have absorbed half of the CO2 released into the atmosphere by human activities in the past 2 centuries. This is causing a decrease in the pH (acidification) of our oceans. Ocean acidification reduces a coral’s ability to build its limestone skeleton.

Reduced coral growth will reduce the ability of corals to compete with other organisms such as algae or sponges as well as reducing their ability to keep up with sea level rise: another predicted effect of global climate change.

Sea level rise
A warming global climate causes an expansion of the water in the sea, which in turn results in a sea level rise. This could have disastrous effects on low-lying areas such as many nations in the Pacific. Importantly, if coral growth is reduced due to ocean acidification their ability to keep up with sea level rises will be reduced. Corals live near the surface of the sea because their zooxanthellae need light to photosynthesise and produce their food. Sea level rises would decrease the penetration of the sun resulting in less photosynthesis and diminishing the supply of food for corals that prefer to live in more shallow water. Coral reefs are also important wave buffers for many low-lying islands providing coastal protection e.g. in the Pacific. 

Coral disease
It is believed that ocean warming can magnify the effects of infectious diseases, which are one of the primary causes of coral loss in the Caribbean. A recent study indicated that very high temperatures increased the severity of white syndrome disease on the Great Barrier Reef.

See more information on the effects of Climate Change on coral reefs

How can we help to reduce the effects of Climate Change?

• Walk or ride your bike to work or school.
• Use energy-efficient light bulbs.
• Turn off lights and electrical appliances at the wall when they are not in use.
• Limit your use of high-energy demanding appliances such as air con or clothes dryers.
• Purchase Green Power from a renewable energy provider.
• Join our Reef Check Monitoring Team and help to monitor and report on the effects of climate change on your local coral reefs.