Category Archives: Biological Sciences

Ocean Acidification Affecting Marine Life

Posted on January 25, 2011 by | 1 comment

As we continue to release anthropogenic carbon into our atmosphere the earth warms.  The ocean however is actually fighting to combat these changes by absorbing some of the heat.  This sounds like an answer to our problems, but there is a catch: the oceans are becoming more acidic.  As carbon dioxide concentrations increase in the seawater, the carbonate concentrations decrease.  Carbonate is a key building block of the shells of many aquatic organisms and the decreased concentration is having negative effects.

Take a minute to check out this video for a quick explanation of how global warming is causing ocean acidification.  YouTube Preview Image

An in depth case study was done on one Arctic mollusc, Limacina helicina, to test the effects of increasingly acidic waters.   The full research paper can be found here, or you can check out the news article for a condensed version here.  These “sea butterflies” or pteropods, were kept in a controlled environment for 5 days to see how well their shells grew under different pH values.  A pH value of 8.09 (which was recorded in the Arctic in 1900) and a pH value of7.78 (the projected value for 2100) were used.  The results were a startling                       28% decrease in linear shell growth for those kept at the acidic pH compared to those kept in the normal ocean pH.

So what does this mean with respect to ocean ecosystems?  Decreased shell growth may not seem immediately fatal to thepteropods an associated ecosystems but the associated decrease in shell density has some larger effects.

Source: antarctica.gov.au - Copyright Russ Hopcroft

In the Arctic pteropods form the base of the food chain and are eaten by many larger organisms. As the oceans become more acidic the pteropods can’t grow or mature as quickly.  They also can’t swim away as quickly from their prey and are eaten more often.  With a diminishing population of pteropods, organisms that rely on them for food will also be at risk.

Pteropods also play an important role in the geochemical cycle, namely transferring carbon to the deep.  However, with decreased shell density pteropods do not sink as well and so they are not transferring carbon.  Without carbon cycling in the ocean the effects of global warming would be much worse.

Source: forum.ntreev.net

These results are not specific to just pteropods; similar studies have been done on other shellfish and corals which found similar results.  Ocean acidification is causing global effects and the scariest part is that most of them are still unknown.  At this point we can only predict how acidic the ocean will get due to global warming and how strongly shellfish and their respective ecosystems will be affected.

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Posted in Biological Sciences, Environment, Issues in Science, Science in the News

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Popular Press Leaps to Conclusions

Posted on January 24, 2011 by | 1 comment

As reported in the Daily Mail, a cup of Bovril may be an important ingredient in a new diet that can reduce the risk of breast cancer. Photo - Flickr: Dave Knapik

Last October the Daily Mail printed an article with the headline: “Strict diet two days a week  cuts risk of breast cancer by 40 per cent’”. The article cites a study published in the International Journal of Obesity, called: “The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women.” Reading these two titles, it’s hard to tell exactly how they’re related. Surely, if the researchers had discovered that the two day a week diet reduced the risk of breast cancer they would have mentioned it in their article’s title.

In fact, the study, published in the International Journal of Obesity, was about WEIGHT LOSS, not breast cancer. It was a six-month study, that put 100 overweight young women on one of two diets and looked at how those two diets affected weight loss. The only mention of breast cancer in the study was that over the course of the six months the levels of two breast cancer related hormones were measured. The Daily Mail was quick to pick up on this measurement and used it to write their article.

The Daily Mail took a big leap when they claimed that the two day a week diet could reduce the risk of breast cancer, given the study never looked at breast cancer risk. However, to be fair, they did admit this in the 19th paragraph where they wrote:

Dr Julie Sharp, senior science information manager at Cancer Research UK, said: ‘This study is not about breast cancer, it’s a study showing how different diet patterns affect weight loss and it’s misleading to draw any conclusions about breast cancer from this research.’

After 18 paragraphs explaining how this diet could reduce risk of breast cancer, this small disclaimer is too little, too late.

The Daily Mail didn’t get away with their misleading publication. The Cancer Research UK blog responded with the post: ““Breast cancer diet” story based on research that wasn’t about breast cancer.” Here they explain why this study does not support the claims made in the Daily Mail.

A week later, Ben Goldacre, of the series “Bad Science” in the Guardian UK, responded with his piece: “The Daily Mail cancer story that torpedoes itself in paragraph 19.” Goldacre focuses his on the fact that 19th paragraph disclaimers aren’t enough to make up for a misleading headline and article. Citing studies on how people read, Goldacre says that most people don’t read entire articles. Most of the Daily Mail’s readers probably never made it to the 19th paragraph.

This shows the importance of looking into news stories. Fortunately, the responses to the Daily Mail article quickly put the truth out there, and anyone who Googled the claim would quickly come across the reality of the research.

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Posted in Biological Sciences, Science Communication, Science in the News

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Corals Are Moving North

Posted on January 24, 2011 by | 4 comments

Flickr: Martin-Klein

As the average temperature of the Earth rises due to climate change, the temperature of the oceans rises as well. These drastic rise in ocean temperatures, affect marine organisms of all shapes and sizes. However, the most prominent effects have been observed on corals. Corals, which are home to thousands of marine creatures, are considered to be some of the most fascinating and eye pleasing marine organisms in the oceans. Unfortunately, they are also highly sensitive to environmental changes.

In a recent article published in Science News (which can be found here), coral migration was studied and tracked by a group of scientists off the coasts of Japan. When they compared current results to data collected from different time periods starting in the 1930’s, they found out that various common coral species have retreated northward, and some have even gone as far as temperate waters. Furthermore, the abundance of coral has decreased proportionately with northward migration.

Mila Zinkova/Wikimedia Commons

If this trend were to continue and not be altered, the population of corals in the oceans will continue to decline. This decline is very unfortunate and it shows how deadly climate change can be. Corals are home to thousands of different marine organisms. Hence, the lost of corals, also causes the direct loss of other marine organisms. Ultimately this can lead to an overall reduction in biodiversity. Furthermore, the decline in coral also jeopardizes recreational activities such as scuba diving and snorkeling.

Although this article, provides excellent evidence to support the fact that corals are moving north and their abundance is decreasing. It does not provide us with ways to prevent or slow down this process. Most of us are already aware of the drastic effects climate change has on marine organisms, but very few of us know how to directly prevent such events from occurring. Hopefully we’ll see more media coverage on prevention methods in the future, so that such events can be prevented or subdued in the future.

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Posted in Biological Sciences, Environment, Issues in Science

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The amazing and curious world in the treetops

Posted on January 19, 2011 by | 4 comments

Photo: thaths on flickr

Is there anything more incredible than the rainforest canopy? Not very likely. The rainforest canopy – the dense area containing the majority of trees branches – is home to some of the greatest biodiversity, or biotic variety, on earth. And where else can you find a complete ecosystem with soil, megafauna, and what is estimated to be half of the world’s plant species – all off the ground?! However, what we know about these incredible “biodiversity hotspots” is very little, as rainforest canopies are among the world’s least understood ecosystems.

So unparalleled is the rainforest canopy in mystery and intrigue that naturalist William Beebe pronounced that, “another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles.” That was back in the early 1900s, and despite much research being done since then, this quote still holds true.

Among what has been discovered, The EarthWatch Institute details some stand-out research findings including the discovery of the first herbivorous spider; work suggesting that perhaps 6 million insect species exist on earth; and the uncovering of thousands and thousands of species previously unknown to us, many of them endemic – meaning they are found nowhere else in the world – to their respective rainforest canopy.

Where else can you find animals as curious as the pink-eyed katydid newly discovered in Papua New Guinea:

Photo: Naskrecki/iLCP

or the Malagasy Red-bellied Lemur?

photo: BBC

Unfortunately, the well-being of much of the world’s fascinating and mysterious rainforest canopy ecosystems is threatened by human activities. Work by William F. Laurence, published in a 1991 issue of Nature, warned that human activities causing forest fragmentation are compromising the health of these unique ecosystems. A study by Erika Styger and fellow scientists published in a 2007 issue of Agriculture, Ecosystems & Environment looked at the large-scale degradation caused by slash-and-burn farming techniques. Additional research keeps pointing at humans as the cause of increasingly unhealthy rainforest canopy ecosystems.

Scientists are currently working to understand the biological and chemical processes at work within the canopy in order to gain a better idea of how we can protect these ecosystems. Some are working to document canopy species composition and interactions while others are expressing concerns over the ability of the rainforest canopy to continue supporting its species in the face of climate change – an area that is beginning to get a lot of research attention. Thus, work is being done to better understand what is happening in the mysterious and marvelous rainforest canopy. Whether we can protect the very-worthy-of-protection rainforest canopy ecosystems before their health is globally compromised remains to be seen.

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Posted in Biological Sciences, Environment, Issues in Science

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