Air Pollution Linked to Heart Problems

A recent study published in PLOS Medicine has linked long term exposure to air pollution to heart attacks and strokes by speeding up atherosclerosis (hardening of arteries). A group of researchers led by Sara Adar, John Searle and Joel Kaufman have found that high concentrations of fine particulate air pollution (PM2.5) is linked to quicker thickening of the two inner layers of the common carotid artery. This study was conducted on 5362 people from six U.S. metrapolitan areas, all with no known heart problems. Scientists studied these people every year for three years, and determined that the thickness of the carotid vessel increased by 14um each year. Those who were exposed to higher levels of residential fine particulate air pollution showed even faster thickening of vessels than of those who lived in the same area.
         What does this tell us? People who are living in areas with higher fine particulate air pollution have a 2% higher risk of stroke than those who live in less polluted areas of the town. These findings can help scientists to explain the associations between long-term PM2.5 concentrations and clinical cardiovascular events.
         This study, and hopefully follow up studies alike should lead individuals to support laws such as the clean air act, and other movements to lower the pollution levels in our environment. We are slowly killing many animals in our ecosystems due to our increased pollution and wasteful lifestyles, and now according to this most recent study, we are also potentially killing ourselves.

                                       REFERENCES:

Public Library of Science (2013, April 23). Air pollution and hardening of arteries.ScienceDaily. Retrieved April 29, 2013, from http://www.sciencedaily.com­/releases/2013/04/130423172706.htm

Adar SD, Sheppard L, Vedal S, Polak JF, Sampson PD, et al. Fine Particulate Air Pollution and the Progression of Carotid Intima-Medial Thickness: A Prospective Cohort Study from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. PLoS Med, 2013 DOI:10.1371/journal.pmed.1001430

Mice Rely on Individual Gene to Avoid Predators

       


          A recent study conducted by a Northwestern University research team lead by Thomas Bozza has discovered genes that are directly associated with how mice react to the smell of predators. While studying olfactory receptors, the research team found that there may be a single gene necessary for controlling a mouses sense of smell, which it relies on to avoid predators such as cats.

 Image:  © cynoclub / Fotolia


         The olfactory receptor they removed is the TAAR4 gene, which encodes a receptor that responds to chemicals in the urine of meat eaters. Mice who have this gene avoid the scent marks at all costs, but those who lack the TAAR4 receptor do not. This reveals that individual genes matter when it comes to sense of smell. Since mice have more than 1000 olfactory receptor genes, one would assume that removing a single olfactory receptor gene would not have a significant effect on the organisms ability to smell. Mice have 15 TAARs, one found in the brain and 14 in the nose, which are used to detect odors. These TAAR genes are very sensitive to amines. Mice lacking all 14 olfactory TAAR genes showed no response to the presence of amines. This led scientists to believe removing single genes may have an effect in the mouses sense of smell.
        Removal of the TAAR4 gene, which responds to phenylethylamine (PEA), a chemical found in carnivore urine, caused mice to have no response to the smell of predator cat urine. However, they still avoided other amines. These genes are highly conserved, and found in all the mammals the team had studied, including humans. Since they are highly conserved, it is likely that they are very important for survival. Neurons in the nose that express TAARs connect to a single region of the olfactory bulb, which receives the first olfactory information. This, may suggest that TAARs create hardwired responses to amines, and possibly even humans.


                                        REFERENCES:
Northwestern University (2013, April 29). Cat and mouse: One gene is necessary for mice to avoid predators.         ScienceDaily. Retrieved April 29, 2013, from http://www.sciencedaily.com­/releases/2013/04/130429154115.htm

Dewan, A., Pacifico, R.,  Zhan, R., Rinberg, D., Bozza, T (2013). Non-redundant coding of aversive odours in the main olfactory pathway. Nature, 2013; DOI: 10.1038/nature12114

Image:  © cynoclub / Fotolia

Sea Urchins Tolerant of High CO2 Levels

   

Image: Kurt L. Onthank

     A recent article from the Scientific American reports that the Purple Sea Urchin may have a genetic background for tolerating a rise in ocean acidity. Their genetic make up is able to adapt to changes in environmental CO2 in just one single life span. This is a very startling discovery, because they are essentially experiencing the effects of evolution in just one life time. The genes of larvae exposed to higher levels of acidity were sampled, and they showed new versions of genes that were better adapted to higher CO2 conditions. These genes became more common, which is basically the start of evolution. After about seven days of development, the changes of genetic information was very evident.
     Although the effects of such short term evolutionary changes are unknown, it seems as though the sea urchins will be able to survive high ocean acidity fairly well. The long term effects of replacing existing genes with new genes is yet to be determined, which makes scientists skeptical about how beneficial the genetic changes can be. Studying these purple sea urchins is going to help scientists figure out what organisms are at the highest risk for extinction due to climate change. The fact that sea urchins have such large population sizes makes it much easier for evolution to take place, so organisms who already have a low population would most likely not experience such rapid evolution. Follow up research and experiments should be conducted in order to find out the real effects of such rapid evolution, and how it will aid the sea urchin populations in surviving climate change.

                                                References:
     Biello, D. (2013) Can Evolution Beat Climate Change? Scientific American. Available: http://www.scientificamerican.com/article.cfm?id=sea-urchin-evolution-to-cope-with-climate-change-ocean-acidification

     Pespeni et al., (2013) Evolutionary Change During Experimental Ocean Acidification. Proceedings of  the National Academy of Sciences of the United States of America. p 1-6. doi.10.1073/pnas.1220673110

Image Credit: Kurt L. Onthank

Our Response to Ocean Acidification

To conclude my last two blogs on the effects of ocean acidification on corals reefs, fish, and also other marine calcifiers, I am going to discuss several different steps and strategies to combating the issue. Everyone is aware of the effects of CO2 on the environment, and the potential damage it can have if CO2 levels continue to rise. The main causes of high levels of CO2 can be attributed largely to the burning of fossil fuels and an increase in human activity worldwide. CO2 levels are currently at about 385 ppm, which is way higher than scientists would like it to be. Estimates show that in less than 30 years we will see CO2 levels in the ocean over 450 ppm, which is too high for calcifiers to secrete their exoskeletons or shells. This would cause a collapse of many coral reef ecosystems and the organisms who rely on them to survive.

      If we act now to prevent CO2 levels in the atmosphere from continuing to rise, we can save the marine calcifiers and potentially reverse the damage that has already been done. The Waxman-American Clean Energy and Security Act was passed by the House of Representatives, and the Senate has also announced its willingness to act on this issue as well. The government panel has concluded that in order to save the reef ecosystems and stabilize CO2 levels at 350 ppm, emissions need to fall 85% lower than they were in 2000. As much as this may seem impossible, it is not. You can contact your Senator based on location, via email, phone call, or even visiting their office. Explaining your concern for high CO2 levels effect on the ocean and urging your Senator to move strong climate legislation to reduce green house gases can have a great influence on future laws and acts passed in order to bring atmospheric CO2 to safer concentrations. 

                                                    References: 

     
      Repass, R., Rodgers, Sally-Christine., (2012). Act Now to Stop Ocean Acidification. Retrieved from http://www.coral.org/node/4258

      Hance, Jeremy. (2008). Stopping Ocean Acidification Would Save Billions of Dollars in Revenue. Retrieved from http://news.mongabay.com/2008/1112-hance_oceans.html

Effects if CO2 on Coral Reef Fish Learning

     After doing follow up research on my previous blog, "Coral Reef Acidification", I came across a journal on the effects of CO2 on learning of reef fish. I found this to be very interesting, because previous searches had only showed the effects on coral reefs. I think the effects of CO2 on coral reef environments is something that should be more heavily researched. If the effects on the atmosphere are so negative, the effects on the ocean must be just as bad, considering the ocean absorbs more than half the CO2 that is emitted into the atmosphere. 

     The experiment "Effects of Ocean Acidification on Learning in Coral Reef Fishes" provides an explanation for the possible detrimental effects of high CO2 concentrations on the learning abilities of juvenile Damselfish. They tested the effects of elevated CO2 levels on their response to predators, the dotty back, and the Damselfish failed to respond the way they normally do. Even when tested 5 days after CO2 exposure, the damselfish still failed to recognize the dotty back as a predator. The damselfish were exposed to the elevated CO2 levels since birth, so it wouldn't resemble a sudden rise in CO2 exposure. The results of the experiment showed that damselfish exposed to elevated CO2 levels did not responded differently to predator odor. If elevated CO2 levels are currently effecting coral reefs, then they would also be effecting new born fish as well. Although these are short term studies, the results emphasize the need for more studies on the potential long term effects of carbon dioxide on marine ecosystems. 

To the left is an image of an Arabian Dottyback 

Below is an image of a Tufi Damselfish 

References :

       Ferrari MCO, Manassa RP, Dixson DL, Munday PL, McCormick MI, et al. (2012) Effects of Ocean Acidification on Learning in Coral Reef Fishes. PLoS ONE 7(2): e31478. doi:10.1371/journal.pone.0031478

      Adams, J (2010). "Tufi damselfish and brilliant cap     clownfish from Papa New Guinea are the latest reef gems revealed by Seasmart". Retrieved from http://reefbuilders.com/2010/06/22/tufi-damselfish-and-brilliant-cap-clownfish-from-papua-new-guinea-are-the-latest-reef-gems-revealed-by-seasmart/

Schultz, H.C. III (2008). "The Dottybacks". Retrieved from http://www.reefkeeping.com/issues/2002-02/hcs3/

Coral Reef Acidification

My first blog is a follow up on a previous class presentation, on the effects of high atmospheric CO2 levels on coral reefs. Currently, environmentalists are concerned about the bleaching and productivity loss of reef builders due to rising CO2 levels. Coral bleaching and calcification (used for reef building) are two aspects taken into account  when looking at the effects of CO2 on coral reefs. High levels of CO2 can cause corals to start bleaching and die, while high temperatures can enhance the effects of bleaching and calcification rates. Studies have shown that bleaching occurs as a result of CO2's impact on photoprotective mechanisms of the photosystems ( Anthony, K.R. 2008). These results are part of an 8 week study done to compare bleaching, productivity, and calcification responses of crutose coralline algae (CCA) and branching ( Acropora) and massive (Porites) coral species in response to acidification and warming. In this study, 30 tanks were set up with alternating CO2 levels for the three different types of corals.

      The results of the experiment show that high CO2 levels resulted in 40-50% bleaching for CCA and Acropora after the 8 weeks. Effects of CO2 dosing on bleaching was stronger than the effect of temperature on bleaching as well. The high-CO2 dosing led to a two to three fold increase in bleaching relative to the control, whereas high temperatures led to only a 20% increase in bleaching for those species. The Porite species showed a less sensitive reaction and bleached to a max of 20% in high-CO2 dosing/ high-temperature. High temperature, however, enhanced bleaching by 10-20% in CCA and Acropora, but up to 50% in Porites.
      Below is a picture of a coral reef structure before, and after being effected by coral bleaching.

     The picture above shows calcium carbonate concentrations in the years 1765 and 1995, as well as predicted concentrations in 2040 and 2100. Image credit: Quirolo, C.


      The above image show concentrations of calcium carbonate in the years 1765 and 1995, as well as the predicted concentrations in 2040 and 2100. Image credit: Kleypas et al., (2006).

   Results of the tests of CO2 levels on reef builing (calcification) showed much more astonishing results. CCA response to high-CO2 dosing was very sensitive and showed a 130-190% reduction in calcification rate realtive to control at low and high temperatures. The Acropora calcification rate was supressed significantly by warming only when high-CO2 dosing, and Porites did not show a clear response to warming.
     The results of this experiment are very conclusive and prove that a rise in CO2 concentration in the environment will have a severely negative impact on the well-being of coral reefs around the world. While rising temperatures alone don't have a serious effect, when combined with the effects of increased CO2 concentrations, it can lead to even more reef destruction. It is clear that prolonged exposure to CO2 causes bleaching, and low calcification rates. As a result of this experiment, people should take more into consideration when studying the effects of warming and CO2 on corals. It is clear that these processes pose a threat to our environment, and that more studies need to be done to explore these issues. People should also start taking extra precautions when taking part in air pollution, but all types of pollution as well.

                                                                References

Anthony K.R. et al., (2008). "Ocean acidification causes bleaching and productivity loss in coral reef builders. Proceedings of the National Academy of Sciences. Vol 105 (issue 45) p. 17442-17446. Retrieved from http://www.ncbi.nlm.nih.gov/m/pubmed/18988740/

Quirolo, C (2010). "Reef relief/ Marine Photo bank." Climate, Carbon and Coral Reefs. http://www.wmo.int/pages/prog/wcp/agm/publications/documents/Climate_Carbon_CoralReefs.pdf 

Kleypas et al., (2012). "Impact of Ocean Acodification on Coral Reefs and other Marine Calcifiers: 
A Guide to Future Research. Retrieved from http://www.reefbase.org/resource_center/publication/pub_25651.aspx