Author Archives: erinleonard

Viruses: The Lifeline of the Ocean

Photo from Flickr user moonjazz

Most of us think of viruses as destructive and harmful, but a new study could change your mind.  Research done by Dr. Emma Shelford from the University of British Columbia, and a team of scientists, suggests that viruses may be the lifeline of the ocean.  We had a chance to sit down with Dr. Shelford and discuss the study:

 

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The research looks into how the presence of viruses in the ocean are affecting the growth of phytoplankton, which are very small organisms that live in the surface water of the ocean. Through a process called photosynthesis, they use the energy from the sun, and nutrients from the water to fuel themselves.

Satellite image of phytoplankton growth off the coast of Vancouver Island. Photo from Flickr user eutrophication&hypoxia.

The study was conducted in two locations: False Creek, in Vancouver BC, where phytoplankton and nutrients in the water are high and the Indian Ocean, a nutrient-poor region where there is low phytoplankton abundance.  After analyzing the water samples from both locations, they found that the presence of viruses resulted in an increase in the growth of phytoplankton.

How do viruses affect the growth of phytoplankton?

Viruses reproduce by a process called viral lysis, where they infect a bacterial cell.  At the end of the process, the bacterial cell bursts.  This releases all of the bacteria’s nutrients into the water.  The nutrient that the research focuses on is nitrogen. This nutrient is very important in the growth of phytoplankton.  So with an increase in nitrogen in the water, there is also an increase in phytoplankton.  The role of viral lysis is explored in further detail in this descriptive podcast:

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How does this research affect us?

Phytoplankton form the base of the food chain. Photo from Akash Aujla

The research has given us a new perspective on what role viruses take in the ocean. By helping the growth of phytoplankton in the ocean, viruses are also having an impact on the world’s ecosystem.  Phytoplankton form the base of the food chain.  Their production is key to the survival of organisms higher up in the chain.  More lower level organisms, means more food for upper level organisms, and eventually more fish and other seafood that we consume on a regular basis.

Phytoplankton also produce half of the oxygen that is in our atmosphere.  As a byproduct of creating food for themselves through photosynthesis, they release oxygen into the atmosphere.  Also through photosynthesis, phytoplankton help remove carbon dioxide from the atmosphere.  This is especially important because this gas is a contributor to global warming.  It is one of the most prominent greenhouse gases and acts like a blanket over the Earth that prevents heat from escaping.

It is amazing to think that viruses are actually an important and integral part of the ocean ecosystem. They play a huge role helping support life in the ocean and the entire world.

Journey To The Unknown

James Cameron is taking a break from filming blockbuster movies like Titanic and Avatar, to travel to the deepest depth of the ocean – The Challenger Deep.  He plans to travel to the bottom of the ocean in his custom built submarine while documenting his journey on film and gathering samples for scientific research.  The dive is supposed to happen in the next couple of weeks.

A map showing the location of The Challenger Deep and Mariana Trench in the Pacific Ocean. Photo from Flickr user Mudkipz_KGM

 

The Challenger Deep, located in the Mariana Trench in the Pacific Ocean, is the deepest point recorded in all the oceans. At 11 kilometers below the surface, it is more than two kilometers higher than Mount Everest – the highest point on Earth.

 

 

 

Mr. Cameron will make the dive alone, in his state of the art, custom built submarine.  His vast imagination that we see come to life in his movies has now come to life for real.  The sub is reminiscent of a bullet.  The 7.3 meter long, one-person vessel, will travel vertically and reach the bottom of the ocean in less than two hours. It uses very heavy steel plates to help the sub descend to the bottom. When the vessel is ready to go back up, the plates are dropped and it will rise to the surface.  However, the submarine can still be controlled to hover in one spot, or glide through the water.

The effects of pressure in deep ocean water on styrofoam. Picture from Flickr user NOAA's National Ocean Service

The pressure in the submarine will remain constant for the entire trip.  Although the pressure at this depth is usually crushing, a newly designed foam that maintains buoyancy without being crushed and warped by the immense pressure, is the main frame of the vessel.  The pressure will cause the foam to shrink about two and a half inches, but the foam will remain intact.  It is this foam that helps the vessel rise to the surface as well, as the foam is lighter than water.

Mr. Cameron will be able to stay at the bottom for around six hours. The submarine is equipped with spotlights and cameras to document the journey in high-resolution 3D video.  The sub also has tools for collecting samples including a robotic arm, and a suction sampler that acts like a vacuum to suck up things like small organisms.

The Challenger Deep has been reached once before in 1960, but only for 20 minutes.  The pilots were not able to capture any images or samples because of the dust that was disturbed by the landing of their vessel.  This area of our world is not very well known.  Needless to say, discoveries that Mr. Cameron could make, like previously unknown organisms, would have a profound impact on scientific research. His journey to the Challenger Deep sounds amazing and exciting. I cannot wait to see what he finds in the unknown depths of the ocean.

Video from National Geographic:

Follow James Cameron’s Journey on YouTube

References:

http://deepseachallenge.com/

http://www.nytimes.com/2012/03/08/science/earth/james-cameron-prepares-to-dive-into-mariana-trench.html

How The Zebra Got Its Stripes

Ever wonder why zebras have that distinctive black and white striped pattern? Scientist Gábor Horváth and his team have come up with a new explanation: Zebra’s stripes evolved to help ward off blood-sucking tabanids, more commonly known as horseflies.

Zebra

Photo from Flickr by garymacfadyen

Originally, scientists thought that zebras were white animals that developed black stripes over time. They thought this because the underbelly of the animal is white.  However, it has been found that zebra embryos actually start out black and develop their white stripes during their gestational period.  Horváth and his team hypothesized that zebras developed their white stripes to become less attractive to horseflies. Horseflies are attracted to horizontally polarized light.  This is because these insects like to mate and lay their eggs in water, which polarizes light horizontally.  Female horseflies, the ones that do the blood-sucking, are also attracted to the horizontally polarized light reflected from animals’ hides.  Darker surfaces reflect horizontally polarized light; this explains why horseflies are more attracted to darker horses than they are to white ones.

Horsefly

Horsefly photo from Flickr by Nigel Jones (insectman)

The researchers conducted their study at a horse farm close to Budapest, which was heavily infested with horseflies. The team used models of horses with black and white striped patterns, which varied in the angle, density and width of the stripes.  Also, they reflected different directions of polarized light off the models.  Their prediction was that completely white models would have the least, dark models would have the most, and striped ones would have an intermediate amount of flies.  Using oil and glue to trap the flies, it was found that the striped models actually attracted the least amount of flies.

Using their data that was collected, they found that the width of zebras’ stripes are positively correlated with the striped patterns that horseflies were least attracted to.  It was also seen that narrower stripes were less attractive to horseflies. This led Horváth and his team to conclude that the zebra developed its striped pattern to ward off horseflies.

A Zebra Camouflaged in tall grass. Photo from Flickr by Mister.Tee

There could be other reasons why zebras evolved stripes.  One reason may have been to camouflage into tall grass, as most of the zebra’s predators are colour blind. It is possible that the stripes may have evolved to confuse predators, making it hard to focus on one zebra at a time.  Another reason may have been for reproduction, with the stripes being a way for the animals to tell each other apart and choose mates.

It is likely that the evolution of the zebra’s stripes is a combination of many or all of these ideas, and there could also be other reasons.  One thing is for sure, nature is fascinating, and it is amazing to know that it is very likely that zebras evolved stripes to act as a natural insect repellent.  I may test this theory myself; you might see me wearing stripes next time I’m hiking through the woods!

References:

http://www.sciencedaily.com/releases/2012/02/120209101730.htm

http://jeb.biologists.org/content/215/5/iii

http://earthsky.org/biodiversity/how-zebras-got-their-stripes

 

2012 will be even longer than you thought

This year is special for many reasons.  One reason being that it has an extra day. But did you know that it will actually be 366 days plus one second longer? We have all heard of leap years, but have you heard of the leap second?

Prague Astronomical Clock. Photo from Flickr by simpologist

For about the past 1000 years, the rotation rate of the Earth has been slowing down. This has made our day of 24 hours, or 86 400 seconds, about 0.002 seconds longer.  Over the course of a year, this adds about 1 second.  Therefore, a second (the leap second) is added to the Coordinated Universal Time approximately every year.  This maintains its time within 0.9 seconds of the timescale of the rotation of the Earth, also known as Universal Time.  The rotation of the Earth can vary, which means that the leap second it not added at the same time every year, nor is it added every single year.  The last leap second was added in 2008, the next one will be added June 30th this year.

Controversy

The United Nations Headquarters in Geneva. Photo from Flickr by calistan

Thursday, January 19, 2012, a United Nations meeting was held on international telecommunications.  At this meeting a recommendation was supposed to be made to keep or abolish the leap second.  However, with the delegates not being able to come to a consensus, the subject was put on hold until 2015.

The United States is the main advocate for eliminating the leap second, concerned about the cost and the potential havoc it could wreak.  Satellite navigation systems rely on the precise synchronization of time for communications.  When the leap second is added, these communications could be disrupted. Computer networks could also have a hard time adding an extra second to their clock.  If the second is added inconsistently across the world, potential disasters could occur in air traffic, financial trading markets, and cell phone networks.

On the other hand, countries like Britain, China, and Canada want to keep the leap second.  They argue that in the 40 years that leap seconds have been added, there have been no problems or disasters.  The elimination of the leap second would stop our day from being in sync with the rotation of the Earth and the Sun.  Also, thousands of years from now it could be noon on the clock, but the sun indicates that it is dawn.  The advocates for the leap second propose that the elimination of the leap second could cause even more difficulties.  One hundred or so years down the line, a leap minute may have to be introduced and this could cause more problems than the leap second.

For now, we will continue to introduce the leap second every year or so.  With the rotation of the Earth and Sun always changing we do not know what the future holds.  Will we keep the leap second?  Only time will tell.

References:

http://www.bbc.co.uk/news/science-environment-15563170

http://www.nature.com.ezproxy.library.ubc.ca/news/2011/111108/full/479158a.html

http://www.nytimes.com/2012/01/19/science/to-keep-or-kill-lowly-leap-second-focus-of-world-debate.html?_r=2&ref=science

http://www.nytimes.com/2012/01/20/science/the-leap-seconds-reprieve.html?ref=science

http://iopscience.iop.org.ezproxy.library.ubc.ca/0026-1394/38/6/6/pdf/0026-1394_38_6_6.pdf