Extreme Heat Bleaches Coral, and Threat Is Seen
http://www.nytimes.com/2010/09/21/science/earth/21coral.html
Picture: This photo shows coral that has been bleached under extreme stress.
Summary: Extreme heat has put coral reefs under extreme stress, which gives scientists fear that there will be widespread die-offs. From these die-offs, even the richest ecosystems and fisheries that feed people will become greatly endangered. In 2010, coral from all over the world reacted to heat stress the same way - by bleaching, which is shedding their color and going into “survival mode”. Scientist hoped that 2010 would not be as bad as 1998, when approximately 16 percent of the world’s shallow-water reefs died. Scientist say bleaching is linked to climate change; they have warned for years that the highly excessive heat sensitive corals would serve as an early indicator of the distress on this planet from greenhouse gases. Although coral reefs only occupy a small fraction of the sea, they are called the “rain forests of the sea”, housing a quarter of all marine species. During the 1983 El Niño, there were drastic die-offs of coral; 2010 was an El Niño year. Clearly, natural weather variability plays a role in the overheating of the reefs, but scientists cannot, by itself, explain what has become a recurring phenomenon.
Opinion: I never knew coral reefs bleach themselves under extreme heat stress. It is sad how the coral can serve as an indicator of what greenhouse gases have done to this planet. So many coral reefs have already died out because of the heat, and I have no doubts that more will die off in the future. However, I find it interesting how the coral reacts to heat. Shedding their color and going into “survival mode” is a very strange way of reacting to the heat. What the coral does reminds me of the science section on adaptations. I would relate the coral’s reaction to a behavioral adaptation, since it is reacting a certain way when faced with an outside force.
Questions:
1) Is there a particular reason why the coral sheds its color under extreme stress?
2) Are there other things that stress out the coral that make them shed their color? If so, what, and why?
3) How many coral reefs have died because of the issue of bleaching?
4) Why are corals so heat sensitive?
-Angela Mei
Until reading this article, like Angela I had no idea that coral reefs bleach themselves under heat stress. It is horrible to see that the coral reefs that are homes to many marine species are getting harmed and are unable to provide a habitat. This kind of reminds of density independent limiting factors that we learned about in class. The temperature is impacting the population growth no matter how many and what type of coral reefs there are. Again, I agree with Angela on the fact that it is really unique and interesting that coral reefs react to heat in such an odd way. I don't really understand how we would be able to control this easily, without having to take too many tiny precautions that aren't going to be possible. I've always learned and seen coral reefs being very colorful and a unique factor in the ocean, but now I'm seeing a whole other side.I hope that the coral reefs start finding a way to fight the heat stress, and to stay the way there are, so that they can keep the oceans biodiversity high and give many organisms a habitat.
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http://oceanworld.tamu.edu/students/coral/coral5.htm
The link above talks about how many coral reefs have been destroyed and also how humans indirectly and directly impact the bleaching. This site also gives some information on how coral gets its color and how it is lost through the process of heat stress bleaching. This site also has a picture of a map showing the areas with coral reefs in danger. It also has some information on groups whose purpose is to save the coral reefs, and how some people go about this process. This site also has more information of coral reefs in various aspects.
http://www.reefresilience.org/images/Bleaching-and-mortality.gif
The link above is of a picture that shows the biological aspect of the change in coral when bleached. It shows the substances that are in the coral and then removed from the coral.
This article was very interesting and I enjoyed reading it. I find these kinds of articles really cool. It is interesting to read about how different species react to green house gases. We all know that these gases are bad, since we have such a large amount of them, but it really puts it into reality when we see how the heat and these gases have effected an organism. I also agree with everyone, and think it is really unique that coral reefs shed their color when they go into "survival mode." This reminds me of when I went scuba diving in Hawaii. I swam over many beautiful coral reefs. They were all brightly colored. I cannot imagine going back to Hawaii and seeing barely any coral reefs and if there were any, them being white. It is just not right. The ocean will lose its a major part of its beauty if this pattern with coral reefs continues. The over heating of our Earth is causing many problems. The coral reef's discoloring is just one example. I would hate to see this species lose its beautiful color over humans' mistakes.
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answer to question 2:
I did a little research and found out that temperatures too hot or too cold, salt concentrations too high or too low and/or light intensities too high or too low can cause the coral reef stress that leads to the shedding of skin. These things cause stress in the coral reefs because they are all extreme versions of something. A coral reef needs very balanced and regular temperature, salt level and light intensity and if these things change to extreme high or low levels it will cause the coral reef stress.
I found this article to be very appealing. I had no idea that coral reefs could have extreme stress from heat and that the stress is caused by greenhouse gases. I also found it interesting that they shed their colors to go into “survival mode.” I planned to go to the Australia and see the Great Barrier Reef and its magnificent colors but if the coral reefs start to lose its colors, I will not be able to see its beauty. It’s ashamed to hear that beautiful habitats like The Great Barrier Reef are becoming hurt by greenhouse gases. I agree with Angela about more coral reefs dying off in the future. I hope we can put an end to coral reef bleaching so coral can keep their beautiful colors.
ReplyDeletehttp://www.learner.org/courses/envsci/unit/text.php?unit=13&secNum=3
This link is a picture of a big section of a coral reef that is bleached. Also in the picture is a colorfully fish and when I compared the fish to the coral, it seems so alive than the coral.
Before I read this article I never knew that coral reefs could bleach themselves due to extreme heat and stress. I find it scary and un-nerving that these things go on in the world without many people knowing about it. When the reefs bleach themselves it is their way of going into “survival mode” and reefs have been doing this from Australia to Texas. Many of these reefs will end up dying off, just like what happened in 1998 when around 16 percent of shallow water reefs died off. The main reason for the death and bleaching of all the reefs is the climate change going on all around the world. For years scientists have used the warning off reef bleaching as a way to see how many greenhouse gases are in our environment. If they continue to die off at a rapid pace, the oceans “rainforests” are going to lose huge amount of biodiversity. I am really going to try and stop global warming more than ever now, because I have always admired coral reefs pretty colors and structure.
ReplyDeleteQuestion 1
The reefs do not actually bleach; they just lose the algae that once helped color the reefs. Coral reefs are made up of polyps that form relationships with algae. The polyps give the algae a place to live and food to eat, and in return the algae captures sunlight to give the polyp’s food and the sunlight causes the algae and polyps to become colored. Under extreme heat though the algae forms toxins and the polyps “kick” the algae out. When that happens, all the color goes with the algae, making it look like the reefs were bleached.