In pictures: a close-up look at the Great Barrier Reef’s bleaching


Justin Marshall, The University of Queensland

These images are a selection of photos taken recently near Lizard Island off the north Queensland coast. They document the ongoing bleaching on the Great Barrier Reef as ocean temperatures continue to be driven upward by climate change.

The bleaching process

Before corals bleach, they are often a deep brown or khaki-green colour. These colours come from the symbiotic algae (sometimes called zooxanthellae) that co-exist with the coral polyp.

Before bleaching…
Justin Marshall/coralwatch.org, Author provided

During bleaching, as the symbiotic algae depart, you can see the beautifully coloured polyps. Sometimes polyps are transparent and we see only the white skeleton beneath. Other polyps may be brightly coloured, as seen here.

…during…
Justin Marshall/coralwatch.org, Author provided

But whether white or fluorescent, these corals are far from happy. Once the final stage of the bleaching process is reached, it is likely the coral has been stressed for days or weeks. From here on, it may recover slowly – by re-acquiring its symbiont friends – or it may die, having run out of energy in the absence of the symbiotic algae that provide it with carbohydrates.

What often happens next is that the coral is covered with a film of turf algae, which takes over the parts of the reef previously colonised by healthy coral.

… and after.
Justin Marshall/coralwatch.org, Author provided

Bleaching can be strangely beautiful

Unfortunately, what we are now seeing on the northern third of the Great Barrier Reef is the death of many of these beautiful organisms. But, as noted above, the bleaching can in some cases be weirdly beautiful, as the corals shed their algal cloaks and reveal themselves.

Bleached corals glow a striking shade of purple.
Justin Marshall/coralwatch.org, Author provided

These pictures show a variety of heavily bleached corals, with almost no remaining symbiotic algae. From this point it is a long, slow road to recovery – even those corals that survive will remain metabolically and reproductively compromised for months.

Purple-tinged bleaching.
Justin Marshall/coralwatch.org, Author provided
Pure white bleaching.
Justin Marshall/coralwatch.org, Author provided

The amazing colours are pigments present in the coral polyps themselves. They are often fluorescent – hence the day-glo appearance of some corals and their amazing fluorescence on torch-lit night dives.

Purple glow.
Justin Marshall/coralwatch.org, Author provided

Some healthy corals display such vivid blues and other colours naturally, not during a bleaching event. But these corals are rare. What we are seeing on reefs in northern Queensland is certainly bleaching.

Pink-tinged bleaching.
Justin Marshall/coralwatch.org, Author provided
Blue tips.
Justin Marshall/coralwatch.org, Author provided
Bleached colonies stand out starkly.
Justin Marshall/coralwatch.org, Author provided

Algal overgrowth

When the polyps die, macro or turf algae take over – a process that is already evident along parts of the 800 km of worst-affected Great Barrier Reef.

Non-symbiotic algae begin to take hold.
Justin Marshall/coralwatch.org, Author provided

Especially in warm or nutrient-rich waters, these algae outcompete any coral trying to settle or spread on the reef, taking over areas that corals previously dominated.

Algae growing on coral tips.
Justin Marshall/coralwatch.org, Author provided
A mix of starkly bleached coral and algal colonisation.
Justin Marshall/coralwatch.org, Author provided

Fish losing their homes

Not only is the turf algal community uglier than healthy coral, but it means the other species that depend on the coral lose their livelihoods too. Eventually, the reef structure itself breaks down, meaning that many fish species will need to move on or die.

That includes fish that feed on coral, such as this Okinawa goby…

An Okinawa goby on a coral colony.
Justin Marshall/coralwatch.org, Author provided

… and those that just use it for shelter, such as this black damselfish juvenile.

Juvenile black damselfish.
Justin Marshall/coralwatch.org, Author provided

The turquoise-blue chromis damselfish form huge clouds or schools over coral heads, and use coral branches for shelter when predators come along. The picture immediately below was taken before bleaching, while the one after that shows the fish on a bleached colony.

Before: chromis damselfish on a healthy reef.
Justin Marshall/coralwatch.org, Author provided
After: chromis damselfish on bleached coral.
Justin Marshall/coralwatch.org, Author provided

Anemones (which are close relatives of corals) are also prone to bleaching, which causes similar problems for the fish that use them for shelter.

Anemones are prone to bleaching too.
Justin Marshall/coralwatch.org, Author provided
Searching for shelter.
Justin Marshall/coralwatch.org, Author provided

Here are some more before and after photos, showing the effects of bleaching on the anemones that species such as clownfish use as a refuge.

Before: fish living on a healthy anemone.
Justin Marshall/coralwatch.org, Author provided
After: fish on a bleached anemone.
Justin Marshall/coralwatch.org, Author provided

Living with coral… or without it

When I saw the coral this perky little blenny is sitting in, I was convinced I was looking at a healthy colony! Maybe Lizard Island was not 100% bleached after all.

Unfortunately, closer examination shows that the coral head has died and a thin film of algae covers the branches. The little blenny is farming his patch and cropping the algae so that it does not become overgrown.

A blenny on the reef.
Justin Marshall/coralwatch.org, Author provided
Tending the algae.
Justin Marshall/coralwatch.org, Author provided

One-third of all marine life spends at least part of its life cycle on a reef. What happens when these reefs disappear?

Current predictions are that coral reefs worldwide could be gone within 25 years. How much will be left after this global bleaching event? How much will be left for future generations?

Given the globally accepted link between carbon emissions, climate change and reef bleaching, the decision to approve the Carmichael coal mine in Queensland right next to the Great Barrier Reef really is adding insult to injury.

The continued loss of the Great Barrier Reef is an environmental tragedy and a huge blow to all Australians who cherish this natural wonder and to the tourists who flock here to see the reef – particularly after seeing David Attenborough’s new documentary on it.

Further afield, coral bleaching is a potential humanitarian crisis in countries that rely on reefs for food and basic livelihoods. Let’s not forget that when Australia burns or sells coal it is contributing to this global problem as well.

The Conversation

Justin Marshall, ARC Laureate Fellow, The University of Queensland

This article was originally published on The Conversation. Read the original article.

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New Zealand: New Fish Species Discovered


The link below is to an article (with pictures) of the new species of fish discovered off New Zealand, known as Flabby Whalefish.

For more visit:
http://news.nationalgeographic.com/news/2012/07/pictures/120724-weird-fish-deep-oceans-animals-new-zealand-science/

Article & Pictures: The Latest High-Tech Green Solutions


The article linked to below has some amazing examples of green solutions – along with photos of them. A great article.

For more visit:
Pictures: 10 High-Tech, Green City Solutions for Beating the Heat.

Article: Octopus Eating a Gull


The link below is to an article about an Octopus eating a Gull. The article includes pictures.

For more, visit:
http://www.birdfellow.com/journal/2012/04/27/who’s_up_for_lunch_a_gull_eating_octopus_in_victoria_bc

Chile – Patagonia: Wilderness Threatened by Massive Dam


The Patagonian wilderness is truly an amazing place. I have never been there, but have been fascinated by it for years. It captures my imagination and wonder anytime I see pictures or footage of it. Now I have discovered that this wilderness is under threat.

The article below reports on plans to construct a massive dam that has the potential to cause massive destruction of the Patagonian wilderness. It would seem that the planned dam is incredibly foolish and will destroy a large section of one of the world’s last remaining wild places.

For more visit:
http://www.washingtonpost.com/world/chile-favors-7-billion-hydroelectric-dams-on-remote-patagonian-rivers-despite-opposition/2011/05/09/AFcA2aaG_story.html

 

Check In: Day 2 of Holiday


I have had a most interesting couple of days on the road and in the bush. Currently I’m in a motel room at Woolgoolga, near Coffs Harbour on the mid-north coast of New South Wales, Australia. ‘Hardly the wild,’ I hear you say, and you’re quite right – it isn’t. The weather was beginning to change I noticed on the final leg of my day’s itinerary, so I decided to hide out in a motel room for the night – good decision, it’s pouring outside.

I won’t give all away – I’ll leave the main description of the holiday to the website – but just some of the ‘downlights’ of the first couple of days for this post.

I didn’t arrive at Cathedral Rock National Park until just on dark, but did get the tent up prior to darkness arriving – when it did, it was dark! The campfire took an eternity to get going as all of the timber was damp and by the time I got it started it was time for bed – all-be-it an early night (7.30pm). I had decided to not spend the money on replacing all of the gear I needed to replace for camping, following the loss of a lot of gear over the years due to storage, etc. I hadn’t done much in the way of bushwalking or camping for years due to injuries sustained in my car crash and a bad ankle injury, so I left it all a bit late. I figured that for this holiday I’d make do and replace the gear with quality gear before the next trip. In short, I’ll get by – but it would have been nice to have some good gear just the same. It was a very cold night let me tell you – and long.

When I reached the heights of my first walk today, standing on top of Cathedral Rock National Park, my digital camera decided to die on me. I knew there was something wrong with it during the ascent as it was really chugging away taking pictures. I did get a couple of reasonable panoramic shots on the top of Cathedral Rock before it died, so that was good. I took stills with the video camera I was using, so it wasn’t a complete loss. When I completed the Woolpack Rocks walk I made the trip to Coffs Harbour to seek a replacement and got one for a reasonable price. It’s just another compact and so I will also buy a digital SLR prior to my next trip I hope. My previous SLR was basically destroyed when the camera cap came off during a multiple day bushwalk and all manner of stuff got into it. It wasn’t digital so I didn’t bother repairing it.

So tomorrow – off to Dorrigo National Park I hope and several lengthy walks I haven’t done before. Hopefully the rain will clear.