El Nino to blame?

Intern at Go Pro Costa Rica scuba diving, Divemaster Internship, Scuba Diving 0 Comments

By Carys Mahoney,

Since arriving in Costa Rica the pure abundance of species has always been surprising and being part of a dive shop the surprises just keep coming from Squirrel monkeys(Saimiri oerstedii) and colourful birds on the side walk to jumping into the ocean and coming face to face with beautiful Jewel moray eels(Muraena lentiginosa), clouds of Sergeant majors( Abudefduf saxatilis) Spotted dolphins(Stenella attenuata) chasing the boat and juvenile White tip reef sharks(Triaenodon obesus) hiding out in caves.
I do not believe the wildlife could get much better but we all know the health of the oceans is in a fragile state and needs the attention of all who realise we need the ocean just as much as the ocean needs us.
The health of the coral is of such importance for all species in the oceans they create the most diverse ecosystems on the planet and support thousands of species of fish, marine mammals and tourism. From each individual tiny polyp to elegant giant manta rays they are all interconnected and need to be in good physical health for each other to survive. The corals of Costa Rica seem to be in a state of limbo right now as coral bleaching has been appearing more and more just off the cost of Manuel Antonio national park where the bleaching has been seen in four of our top dives sights ranging from one small spot at one site to larger amounts of different species of coral being affected dotted around another with more appearing over a matter of weeks.

This of course begs the reason why? Well coral bleaching is an effect caused by the rising sea temperature due to corals expelling the algae (zooxanthellae) which is living in the tissues causing the coral to turn completely white. When a coral bleaches, it is not dead as many may presume Corals can survive a bleaching event, but they are under more stress and the risk of mortality is increased the longer the sea temperature continues at a higher rate.

Coral bleaching
Fig 1. Process of coral bleaching (2015)

After talking with fellow divers the bleaching here has been increasing in the past three weeks to where people have been concerned about the state of the corals and questioning why is this happening on a larger scale than usually seen as I have been told bleaching has had effects here in previous years but always recovered fairly quickly. Then to be informed of the El Nino year happening from the start of 2015, small pieces come together to possibly answer some of our questions about why this is happening at such a rapid rate, after some research the National Oceanic Atmospheric Administration (NOAA) have let it be known the El Nino is happening along the equatorial and eastern pacific ocean and is expected to last to spring 2016 which is long time for this type of event to last and the fate of our coral if this is the case, means it is simply a waiting game. Even though this all seems very alarming there is always something we can learn from mother nature and this is our time to document and learn, the waiting game gives us a chance to use this time to our benefit and the benefit of science!

Healthy coral vs Bleached vs Dead coral
Fig 2. Healthy and bleached coral (2015)

Coralwatch.org is a wonderful website dedicated to the collection of data of coral bleaching all over the world in any ocean and anyone can add their two cents whether you have been snorkelling, scuba diving or walking along the beach and seen a close reef, you can print off a Coral health chart which makes identifying species and colours easily without trawling through endless books and websites trying to find the amazing orange finger like sponge you saw in the caribbean. It is extremely easy to sign up and you can add new dive sites or reefs all the time the more data the more impact your having helping the experts show us the way the world is changing.

Coral health chart
Fig 3. Colour health chart (2015)

National ocean service.(2015). What is coral bleaching?. Available:http://oceanservice.noaa.gov/facts/coral_bleach.html.last accessed 29/07/15
Coral watch. (2015). Welcome to coral watch. Available:http://coralwatch.org/web/guest. Last accessed 29/07/15
Australian government. (2015). Coral bleaching. Available: http://www.gbrmpa.gov.au/managing-the-reef/threats-to-the-reef/climate-change/what-does-this-mean-for-species/corals/what-is-coral-bleaching. Last accessed 28/07/15
Fig3. Mahoney, Carys (2015). Colour health chart.

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