Category Archives: Environment

Less and Less Baby Polar Bears with Melting Arctic Ice

Posted on February 16, 2011 by | 2 comments

We all know of the strong correlation between changes in the environment and the polar bears,but a recent study suggests that the population of this species, Ursus maritimus, could be in real danger with the decline of Arctic sea ice specifically in our country’s Hudson Bay.

Source: Flickr

Article published on February 8th, 2011 in Nature Communications outlines a study conducted by Peter K. Molnar et al. from the University of Alberta who used mechanistic models to predict changes in litter size of cub polar bears for pregnant females in the western Hudson Bay population under expected changes in sea ice.

Sea ice is vital for the polar bears because during the winter feeding season they rely on the solid floes to take them near the waters where there are lots of food source – seals. But with temperatures rising and early breakup of the ice sheets, the bears are forced ashore sooner than in the past. Moreover, “on shore, there is no food available for them,” as the lead author of the study puts it. Thus the bears, particularly females of reproductive age, are storing up less energy for the months that they have to hibernate during pregnancy.

The researchers found that ~28% of pregnant females already failed to reproduce for energetic reasons during the 1990s. Using mechanistic models, they predicted that if spring sea ice break-up happens 1 month earlier than during the 1990s – 40-73% of pregnant female polar bears could fail to reproduce, and if the break-up happens 2 month earlier – 55-100% could fail. On a global perspective, the study states that a similar litter size decline trend may be found in over 1/3 of the polar bear population.

What’s even more discouraging is that “the litter size predictions provided in this study serve as another indicator that the western Hudson Bay population will probably not remain viable under predicted climatic conditions” as the article states.

Heart wenching video that hits home of malnourished  mother polar bear and starving cubs as an example of the conditions that polar bears are and will be facing in the future with current climate change conditions. A Warming Climate Takes its Toll on the Polar Bears of Hudson Bay by Daniel J. Cox

WARNING: NOT FOR THE SENSITIVE SOULS.

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

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Banding on Penguins Not Such a Good Idea Afterall

Posted on January 29, 2011 by | 1 comment

Climate change can be assessed through using the top predators of the Southern Oceans, the penguins. However, a recent study published on Nature have shown that the use of flipper banding may affect one specific population of King Penguins.

The 10-year study indicates that “banded birds produced 39% fewer chicks and had a survival rate 16% lower than non-banded birds“. This finding from the research team from the University of Strasbourg in France brings to the surface the effect of banding on animals, specifically the penguins in order to collect scientific data.

However, the conclusion on the tagging and bands are by no means clear, according to interview with two penguin experts. One of them, Dee Boersma, at the University of Washington stresses that not all bands are created equal, thus the effect on species may be different with different materials, shapes, sizes of the bands.

The study in the end stresses the importance of reconsidering the data collected of the effects of global warming on marine ecosystems from flipper-bands.

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

Posted on January 28, 2011 by | 1 comment

A Deadly Plague Endangers Bats

We’re all familiar with our furry flying mammalian friends, the bats. You can hear their distinct chirps at night, even here at UBC, as they fly around in search for food. However, on the other coast of North America they’re not doing so well.

A new plague is devastating bats in 14 different states and 2 Canadian provinces in the North-eastern part of the continent. It has already killed more than a million bats across 9 different species since it was first discovered in 2006. The disease is a fungal infection caused by Geomyces destructans, commonly referred to as “white-nose syndrome” (WNS), because bats develop white patches on their muzzles and ears.

Photo by Alan Hicks

When the bats go into a state of hibernation for the winter, they lower their body temperature and subsequently reduce the power of their immune system, making them easy targets. The disease  seems to disrupt the normal hibernation patterns of the bats, often causing them to awaken too early. Many of the infected bats appear underweight because they go out in search for food in the winter where there isn’t any. Eventually, the infected bats end up starving to death. Research suggests that the disease is being spread from cave to cave by the bats themselves, since most have been closed down to humans and WNS continues to spread. The mortality rate is very high: about 85% of the bats in an infected cave will die from the disease.

A Boston University ecologist, Winifred Frick, suggests that little brown bats may be entirely wiped out in north-eastern United States in the next 16 years. For all the bat lovers out there, this news can come as a bit of shock, but there are also other repercussions to consider. A colony of bats can consume thousands of pounds of insects in a season. Imagine how many more mosquitoes and crop damaging insects there would be if WNS continues to spread unhindered?

There does seem to be a ray of hope; a bat with WNS was discovered in France last year, but it appeared to be of normal weight. Scientists have speculated that Geomyces destructans must be native to Europe and that bats there have resistances to it.

Hopefully more research in the future will provide a means to protect the bats from infection.

The original article can be found here:  http://discovermagazine.com/2011/jan-feb/13

For more general information on the disease, see: http://en.wikipedia.org/wiki/White_nose_syndrome

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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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