Stories tagged Earth Buzz

Dec
10
2008

As biologists we spend a lot of time observing our focal species but we try to minimize any disturbance our activities might cause. However, sometimes we cannot get the data we need without intruding on the lives of our study species. For example, to determine the number of eggs laid in a nest or to determine when egg laying begins, we need to look inside the nest and doing so could have the potential to disrupt normal bird activity.
Common pheasant's nest: Does the very act of checking to make sure there are eggs in this nest make the eggs vulnerable?
Common pheasant's nest: Does the very act of checking to make sure there are eggs in this nest make the eggs vulnerable?Courtesy Jarosław Pocztarski

In the field of ornithology there has been some concern that nest monitoring could either increase or decrease the risk of nest predation. An increase or decrease in the risk of nest predation could occur for several reasons (1) we are leaving human scent trails to the nest that predators follow, (2) predators are watching us and follow us to the nest, (3) we disrupt the incubation process causing the female to stay off the nest longer or (4) our activity at the nest deters predators.
A study was just published in the AUK (a journal of the American Ornithologists Union - http://www.aou.org/) trying to determine if nest monitoring affects the risk of nest predation in 11 species of birds in the Czech Republic. Using temperature data loggers placed inside each nest to determine when females were present or absent from the nest, Karel Weidinger found that activity at the nest as a result of nest monitoring does not increase the risk of nest predation. However, she did find that the risk of nest predation was slightly lower two hours following observer activity at the nest but this reduced risk did not change overall nesting success. This work supports previous research suggesting that nest monitoring activities do not affect the risk of predation. This is great news for biologists because now we can be more confident that monitoring bird nests does not increase the risk of predation.

Dec
10
2008

Many bird populations across North America have declined in recent years and researchers have been busy trying to determine why populations of birds are declining.
Dusky flycatcher nest: These dusky flycatcher eggs might be safe when it comes to researchers, but something is still amiss here: those speckled eggs are brown-headed cowbirds, not dusky flycatchers. When they hatch, they'll outcompete the flycatcher chicks for food.
Dusky flycatcher nest: These dusky flycatcher eggs might be safe when it comes to researchers, but something is still amiss here: those speckled eggs are brown-headed cowbirds, not dusky flycatchers. When they hatch, they'll outcompete the flycatcher chicks for food.Courtesy West Coast Birding

My research focuses on factors that could affect survival of birds during the breeding season. The breeding season is an important time for birds because this is the time when individuals have an opportunity to raise young and the ability to successfully raise young can have a big effect on the bird population. However, producing young can be quite difficult for birds. In fact, the number one factor that affects the ability of birds to raise young is nest predation. Nest predation occurs when a predator, such as a chipmunk or squirrel eats the eggs or young in a bird’s nest. But do all birds have an equal chance of survival during the breeding season? Research suggests that the chance of survival for a bird’s nest is not equal and chances for survival change during the breeding season. Why might survival change during the breeding season? I have some ideas or hypotheses that might explain why survival changes during the breeding season. I am investigating whether plant cover, food resources for predators, temperature, or number of predators affects the ability of songbirds to raise their young.
When birds build their nests, they often hide them in plants to reduce the chance that a predator will find their nest. But many birds begin building their nests early in the spring and in early spring we often notice that plants and flowers in the forest are just starting to grow. So birds building their nests during this time have fewer plants to hide their nests in which could make their nests more visible to predators, such as chipmunks and squirrels. Because plant cover may be a key factor preventing predators from eating the eggs or young in a bird’s nest, I experimented with plant cover to test the importance of plant cover. I removed plant cover around Wilson’s Warbler nests and compared the fate (i.e., were the parents able to raise their young) of these nests to nests that did not have plant cover removed. I also measured plant cover at nests of Wilson's Warblers and Dusky Flycatchers and compared the amount of plant cover to the fate of each nest.
In addition to seasonal changes that we see in plants, the amount of food available in the forest for critters to eat also changes as we move from spring to summer to fall. Early in the summer, there may be less food available for the predators because pine cones and seeds from other plants are not yet available. If predators such as chipmunks, mice, or jays have less to eat they spend more time looking for food to eat in the forest. The increase in time spent searching for food could also increase the chance that one of these predators will find a bird nest and eat the eggs or young in the nest. Because the amount of food available might affect survival of a bird’s nest I conducted another experiment to find out if this was the case. I provided food (sunflower seeds and corn) to predators to see if providing extra food to predators will increase the ability of birds to raise their young.
Determining how both vegetation and food affect survival of bird’s nests during the breeding season is challenging but fun because I am able to experiment with nature and find out what happens. As a scientist I am like a detective trying to figure out why bird populations are declining. Finding the answer is challenging and exciting, but hopefully we will find an answer that will prevent further losses of our bird populations.

According to British scientists, 2008 will probably be the coolest year this decade. Now, this has been a very warm decade, so that's not saying much. But still, each of the last three years, and four of the last five, have been cooler than their predecessors. Does this mean that Global Warming (tm) has reversed? Leveled off? At least slowed down a bit?

"Absolutely not," says the man whose job depends on finding evidence of continued warming. Interesting how that works out...

Solar car circles the globe

by Anonymous on Dec. 04th, 2008

A Swiss teacher just completed a 17-month trip around the world in a solar-powered car. Louis Palmer made the 32,000 mile trip towing a trailer load of batteries charged by the sun. His journey took him through 38 countries and ended in Poznan, Poland where the United Nation talks on climate change are taking place. the vehicle has a top speed of 55 mph and can travel 180 miles on a single charge. The Solar Taxi's official website has information, updates, photos, and a blog.

Dec
02
2008

Water vapor in action: Hoh Lake, Washington.
Water vapor in action: Hoh Lake, Washington.Courtesy S. McAfee

I hate it when bad news gets confirmed.

That’s just what happened when Andrew Dessler and his colleagues at Texas A&M were able to show that a warmer atmosphere holds more water vapor. Unfortunately, water is a greenhouse gas, so more water vapor means the earth warms, so the atmosphere can hold more water, which is a greenhouse gas . . . I think you can see where this is going. It’s a nasty feedback circle. If the earth stays more or less the same temperature, we don’t worry about this too much because there’s a really good way to get water out of the atmosphere. In fact, it just shut down air and highway travel all over the East Coast.

It may seem like a no-brainer that warmer air holds more water, but these scientists were able to put solid numbers on the link between temperature and water vapor, which is a big deal. They used information from a satellite called the Atmospheric Infrared Sounder to measure the amount of water in the air.

Using information from 2003 to 2008, they found that for every 1 degree Celsius the earth warms, the extra water in the air traps 2 watts for every square meter of the earth. If you stored that up over a square meter for an hour, you could run a 100-watt light bulb for about a minute. Bet you wouldn’t even notice that in your electric bill. But the earth is big, so let’s put it in perspective and do the math.

The surface of the earth is 510,072,000 square kilometers. According to howstuffworks, your run-of-the-mill power plant puts out 3.5 billion kilowatts in a year. That means the extra warming that water vapor adds for every degree the earth gets warmer is about the same as the annual output of 290 power plants, give or take. That’s a lot of light bulbs.

Dec
01
2008

A bear of constant sorrow: The expression on his face speaks volumes.
A bear of constant sorrow: The expression on his face speaks volumes.Courtesy Sketchzilla
Buzzketeer General Liza put me on to this story last week, and I’m glad she did. Folks should know the plight of the polar bear.

So, you know those images of polar bears standing on the edge of ice sheets, looking sad because the ice is shrinking, and they need that ice to, you know, stay alive? You know what I’m talking about.

Well… it turns out that shrinking ice may be the least of their worries.

How do I put this? There’s trouble down south in the far north? A great big bear has a… Oh, forget it. Polar bears’ genitals are shrinking.

Oh, this is bleak. Two genital-based posts in a row? I don’t like it any more than you do, and I know you don’t like it. But we’re being beaten down and overwhelmed by genitals in the news, and we can’t ignore the news.

So, yes, after millennia of fearlessly swimming in an ocean of ice water, the mighty polar bear is finally suffering from shrinkage. But this isn’t one of the many problems that global warming can solve—this little situation is being caused by pollution, not cold water.

Y’all know about bioaccumulation and biomagnification? Toxic compounds can be found at very low concentrations in the environment, but still end up at dangerously high levels in certain plants and animals. This is caused by organisms taking in toxins faster than they can get rid of them, and by animals eating lots of other animals or plants that already have toxins in them. That’s what’s happening in the arctic. Tiny organisms are absorbing certain organic pollutants from the environment, and those organisms are getting eaten by tiny fish, and those tiny fish are getting eaten by bigger fish, and so on until big fish, with lots of the pollutants stored up in their bodies get eaten by an animal that doesn’t often get eaten by anything else, animals like killer whales, arctic foxes, or polar bears.

Biologists studied preserved polar bear genitals (penises, testicles, and ovaries) collected between 1999 and 2002, and found that individual bears with higher concentrations of these organic pollutants (called “organohalogens”) consistently had smaller bits and pieces. The organohalogens act like hormones in the bears, and we all know the amazing things hormones can do.

Now we must ask ourselves that age old question: “What does this mean for the bears?” Well, it seems that bears can’t rely on personality alone for successful mating. Polar bears don’t reproduce that often in the first place, and shrinking reproductive organs (in both boy-bears and lady-bears) is only going to make things trickier. And then there’s that whole ice-shrinking thing, which has probably taken a back seat in the minds of young bears everywhere.

In related news, a couple of polar bears at a Japanese zoo were having trouble conceiving until their handlers finally realized that they were both female. (I imagine that they would still have trouble conceiving, but I think the pressure is off now.) Apparently telling male and female bears apart is difficult as it is.

Nov
19
2008

You may have read a couple weeks ago a NASA report stating that October 2008 was the warmest October ever on record. An enormous hot spot was observed over Siberia, an incredible 10 degrees warmer than normal, raising the global average.

However, the appearance of the words “hot” and “Siberia” in the same sentence made some people suspicious. A couple of bloggers took a closer look at the data, and they found that, for dozens of reporting stations in Siberia, the average October temperature was exactly the same as the average October temperature. That’s pretty much impossible. Clearly what happened is someone copied the numbers from the wrong column, leading to greatly inflated figures, which were then eagerly reported.

So, what can we learn from this little episode?

1) Even experts make mistakes. Though this particular expert, Dr. James Hansen, seems especially prone to making mistakes that support his views. That’s only human, I suppose, but it means we should pay attention to who is publishing a study, and whether they are pushing a particular point of view.

2) Weather is not climate. One sparrow does not make a spring, and one October does not make a global warming crisis. Especially when the October in question was not actually, you know, warm.

3) Read the fine print. Just like the item below, the headline told one story, but the pesky little facts told a very different one. (One of the most important things it tells us is that the folks in charge of monitoring the world’s climate don’t even bother to double-check their own data!)

Feb
08
2008

Building a better future: One piece of junk at a time.
Building a better future: One piece of junk at a time.Courtesy thebigdurian
Just when you started to think things weren’t cool anymore (I know you were thinking that), something great comes up in the news, and turns your frown… upside down.

For the last few years the world has been sulking and pouting over the lack of continents. “We’ve discovered them all,” people say. Or, “Look at that darn Pacific Ocean, sitting there with practically no continents in it.” Or, “Hawaii must be so lonely!” Well, Lonesome No More!, Hawaii, because you’ve got a new friend, a friend the size of the continental United States!

Where did this massive mass come from? And how could such a thing have gone so far unnoticed? Whoa, explorers, one question at a time! The mass came from our own human ingenuity! That is to say, it’s trash! And we don’t really notice it because it’s largely translucent plastic, and because it’s located just beneath the surface of the ocean, so it can’t be seen in satellite photographs!

Now before you get excited and start purchasing real estate (although I like the way you think), our new garbage blob isn’t quite ready for building yet. It’s currently more of a “plastic soup,” held together by “swirling underwater current.” It is, nonetheless, a fairly cohesive chunk of junk, consisting of two connected bodies that span from about five hundred miles off of California almost to Japan.

Like many natural and quasi-natural wonders, however, Trashlantis is being threatened. Primarily by aquatic animals. Nearly 100,000 aquatic mammals choose to kill themselves every year by abusing floating garbage in some way or another, and sea birds have proven to be shameless garbage thieves, spiriting away everything from toothbrushes, to lighters, to syringes from our trashy endeavor. Where’s the proof? Inside their dead stomachs. Try to hide that, birds!

Approximately a fifth of the garbage dumped into the ocean comes from oil platforms and ships. If you want to ensure that Trashlantis remains more than a fable for your children and grandchildren, though, be sure to do your part, and produce as much plastic waste as possible, and dispose of it improperly.

Jul
28
2006

Scientists are studying a 70-mile "dead zone" off the coast of Oregon.

First noticed in 2002, the dead zone is larger this year than in previous years.

What is a dead zone? It's an large area of water that's very low in oxygen and can't support life. (Scientists call this "hypoxia.") Dead zones are caused by the explosive growth of tiny aquatic plants called phytoplankton. When the phytoplankton die, they are decomposed by bacteria. Massive numbers of bacteria use up the oxygen in the water. Any animals that can swim out of the low-oxygen water--like many fish--do so. Others--some fish, many crabs, and others--suffocate because they can't get enough oxygen to live.

Dead crabs: Dead Dungeness crabs on beach, Oregon Coast (Photo by Jane Lubchenco)
Dead crabs: Dead Dungeness crabs on beach, Oregon Coast (Photo by Jane Lubchenco)

In this case, the phytoplankton blooms are caused when north winds cause upwelling in the water column. The cooler water is rich in nutrients, providing a feast for the phytoplankton. When the wind dies down, the upwelling stops, and many phytoplankton die a natural death. Their decomposition results in water that is deadly because it lacks oxygen needed for life.

This year, the upwelling started in April, stopped in May, and started up again in June. The off-and-on upwelling creates a thick mat of organic material that rots and uses up the oxygen in the water. Then, when a new upwelling occurs, the oxygen-depleted water moves toward shore, killing the plants and animals that can't get out of its way.

Measuring oxygen levels: Chris Holmes (left) and Dr. Francis Chan (right), PISCO researchers measuring oxygen levels off the Oregon coast from the OSU research vessel Elakha (Photo by Jane Lubchenco)
Measuring oxygen levels: Chris Holmes (left) and Dr. Francis Chan (right), PISCO researchers measuring oxygen levels off the Oregon coast from the OSU research vessel Elakha (Photo by Jane Lubchenco)

So, why the upwelling? Jane Lubchenco, professor of marine ecology at Oregon State University and a member of the Pew Oceans Commission, told the Associated Press:

"We are seeing wild swings from year to year in the timing and duration of the winds that are favorable for upwelling. ... This increased variability in the winds is consistent with what we would expect under climate change."

Global warming is also the suspect in dead zones off Namibia, South Africa, and Peru.

(The dead zone in the Gulf of Mexico at the mouth of the Mississippi River is caused by agricultural runoff containing fertilizers. The river carries all those nutrients into the Gulf, creating algal blooms that use up all the oxygen.)