A third of reef-building corals around the world are threatened with extinction, according to the first-ever comprehensive global assessment to determine their conservation status. Corals produce reefs in shallow tropical and sub-tropical seas and have been shown to be highly sensitive to changes in their environment. The study findings were published July 11, 2008 by Science Express. 
Built over millions of years, coral reefs are home to more than 25 percent of marine species, making them the most biologically diverse of marine ecosystems.
(Photo Credits: National Oceanic and Atmospheric Administration)
Did you know that –
Healthy coral reefs support commercial and subsistence fisheries as well as jobs and businesses through tourism and recreation?
The coral reef structure buffers shorelines against waves, storms and floods, helping to prevent loss of life, property damage and erosion?
Coral reefs support more species per unit area than any other marine environment, and are living museums that reflect thousands of years of history?
Coral reefs are considered by some scientists to be the medicine cabinets of the 21st century?
Every year, millions of scuba divers, snorkelers and fishermen visit U.S. coral reefs?
(Excerpted from NOAA Coral Reef Conservation Program
)
As summarized in the Science Daily article, One-third Of Reef-building Corals Face Extinction, researchers identified the main threats to corals as climate change and localized stresses resulting from destructive fishing, declining water quality from pollution, and the degradation of coastal habitats. Climate change causes rising water temperatures and more intense solar radiation, which lead to coral bleaching and disease often resulting in mass coral mortality.
Shallow water corals have a symbiotic relationship with algae called zooxanthellae, which live in their soft tissues and provide the coral with essential nutrients and energy from photosynthesis and are the reason why corals have such beautiful colors. Coral bleaching is the result of a stress response, such as increased water temperatures, whereby the algae are expelled from the tissues, hence the term “bleaching.” Corals that have been bleached are weaker and more prone to attack from disease. Scientists believe that increased coral disease also is linked to higher sea temperatures and an increase in run-off pollution and sediments from the land.
Researchers predict that ocean acidification will be another serious threat facing coral reefs. As oceans absorb increasing amounts of carbon dioxide from the atmosphere, water acidity increases and pH decreases, severely impacting corals’ ability to build their skeletons that form the foundation of reefs.
The 39 scientists who co-authored this study agree that if rising sea surface temperatures continue to cause increased frequency of bleaching and disease events, many corals may not have enough time to replenish themselves and this could lead to extinctions.
Connecting to the National Science Education Standards
There are many connections between coral reefs and the NSES Life Science strand – biodiversity, life cycle, symbiosis, just to name a few – but for the article highlighted in this post, the grade 5-8 Science in Personal and Social Perspectives strand might be more appropriate. During the middle grades, students should begin to develop a more conceptual understanding of ecological crises such as the cumulative ecological effects of pollution. Other crises occur when an area becomes overpopulated and the environment becomes degraded due to the increased use of resources. One thing to point out – not all reefs are endangered. Students should understand the causes of environmental degradation and resource depletion vary from region to region and from country to country.
I’m sure middle school students are familiar with the term coral reef (most have seen the animated film Finding Nemo) but do they know the location of reefs around the world? Do they know how important they are and what is happening to the many of them? ReefBase: A Global Information System for Coral Reefs provides a map of the world that shows where reefs are found. The map also allows you to see where certain coral reef diseases have been spotted. You can also view the maps year by year. Having a visual representation showing the increased incidence of disease or the reduction of the area that is covered by coral reefs is very powerful. Ask students to think about what would happen if coral reefs become extinct. Why would it matter and to whom?
Here are additional resources from the NSDL Middle School Portal related to coral reefs:
Subscribe to the NOAA Coral Reef monthly newsletter
NOAA Coral Reef Conservation Program
Exploring the Environment: Coral Reefs
2008 was the International Year of the Reef, so check out those resources.
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Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.
Carbon Dioxide Emissions Threaten An Ocean Calamity
Many of us who love the ocean are likely reading with alarm the news reports on the impact of CO2 from the burning of fossil fuels that is creating ocean acidification and a survival crisis for our coral reefs. In most of those reports the emphasis is given to the threat to and ideas for saving the beautiful coral reefs by reducing emissions, our carbon footprint. While it is good to reduce the fossil fuel and other green house gas emissions we are all contributing, I beg to differ with the position that reducing our global carbon footprint will help save our ocean bathing beauties, the reefs. It’s not that I don’t fully support reducing our carbon footprint, I am rather more concerned about the more potent role of the deadly dose of anthropogenic (fossil) CO2 already in the air on its way to our surface ocean waters. Those hundreds of billions of tonnes of CO2 from the fossil fuel age burning, the bulk of which we’ve emitted in the past 75 years, is a massive carbon bomb already airborne and slowly but surely dissolving (exploding) into the surface ocean. By most accounts CO2 in the atmosphere takes on the order of 200 years to equilibrate with the surface ocean. As it dissolves in the surface ocean it makes the water more acidic. The pH (acidity) drop of 30% that we’ve been recording of recent is just the proverbial tip of the dry-iceberg.
As the surface ocean absorbs the rest of this deadly dose, regardless of whether we emit more which we surely will do, the acidification process already destined to occur is more than sufficient to change ocean ecology in far wider and disastrous fashion than merely scalding the bathing beauty reefs at the shore. In fact the devastating effects CO2 has on the ocean is not proceeding only via acidification, H2O+CO2=H2CO3 (carbonic acid), there is a secondary pathway wherein CO2 is enhancing the greeness of the planets dry lands. This added greenery is is a major benefit our high and rising CO2 delivers to droughty grasses who are losing less water via evaporation and transpiration as they take CO2 from the enriched air, are remaining green and growing bushier each spring, and as such are superior ground cover thus reducing topsoil loss in the wind. Tragically that dust in the wind is the major source of vital mineral micronutrients for the open ocean. Prophetically it seems, all we really are is dust in the wind.
So as our reef beauties cry out and dissolve like Dorothy’s wicked witch in our acidifying oceans, the acidification will certainly continue for at least another century, unabated even if we never emit another molecule of fossil CO2 into the air. At the same time as the oceans suffer this chemical shock treatment, akin to those we give our swimming pools, they will continue as well to lose their phyto-plankton and photosynthetic capacity to counter this onslaught. The loss of net primary productivity (ocean greeness), NPP, is reportedly 17% in the North Atlantic, 26% in the North Pacific, and 50% in the sub-tropical tropical oceans. Last spring a scientific report of a transect of the Eastern Pacific between French Polynesia and Chile reported it found “the clearest water on Earth. In the middle of the Pacific the waters were of such clarity that they even exceeded the clarity of the former record holding lakes which lie beneath a mile of ice on the Antarctic continent, in the cold and dark for a million years. Clear water is lifeless water and while it may be a scientific curiosity under the Antarctic icecap it is a horrifying finding in what should be an ocean murky with an abundance of life.
We can find the fundamental proof of the depth and breadth of this problem by considering it from the point of view of basic chemical thermodynamics. Indeed we have expended a hundred terrawatts or so burning fossil carbon to put that deadly dose of CO2 into our atmosphere and ocean. The present human energy use continues at about 12 terrawatts per year today. No trivial energy savings will serve to counter the certain first principals chemical effects of this burning of fossil carbon as it impacts the biggest and most sensitive ecosystem on this small blue planet, the oceans. We can still trust in what the Second Law of Thermodynamics teaches us in that one must balance chemical equations energetically. If we are to address a problem created by terrawatts of energy we must devote terrawatts of energy for the cure. In this case those curative terrawatts better be emission free or we are lost.
So where is there a source of emission free terrawatts of curative power we can devote to saving the oceans and help restore the balance of Nature? It is of course ONLY available from ocean photosynthesis and therein lies the course we must chart to restore our oceans. We must not simply imagine the damage we’ve prescribed can be ignored by staring only ahead and not behind. We must not only take actions that assume the present mortally wounded state of the oceans is something we can’t deal with. No mere conservation ethic or effort will suffice, we are far to far over the tipping point for that to work. We must replenish and restore ocean plant life and photosynthesis for there in the vast living ocean expanse the terrawatts of solar power, captured by living green plankton, can be found and used to compete with the H2O+CO2=H2CO3 reaction. There in lies our only hope if we act now to assist the ocean plants, phyto-plankton, to convert CO2+Sunlight in the ocean to life instead of death. Without replenished mineral micronutrients, without our determined efforts to administer the antidote, life in the oceans, and on this small blue planet, will surely not remain as it is. It will revert to the cyanobacterial; state the oceans were in 600 million years ago before green plants made abundant oxygen and higher life forms, including ourselves, evolved.
My hope in writing to you with this information is to inspire your curiosity and perhaps engagement in this critical issue facing our environment. If you have any questions I would be happy to provide what answers I can.
Planktos Science
San Francisco
http://www.planktos-science.com
Oh My God.. That’s something awful. Indeed, nature is trying to say us that things are getting worst each day. And this is happening because of us, of course. Everything we do damages the whole nature and, in the end, our own health.