You probably know that plants "inhale" carbon dioxide and "exhale" oxygen, but did you know that plants also release water into the air when they exhale? This process is called transpiration, and it plays an important part in our planet's water cycle. I mean, just think of all the billions of plants out there, all of them transpiring 24/7--that really adds up.
Unfortunately, increasing carbon dioxide in the atmosphere has yet another impact on our ecosystems--it reduces transpiration. You see, plants have these tiny pores on the undersides of their leaves called stomata. The stomata open and close depending on the amount of carbon dioxide available in the air and how much they need of it.
It's kind of like your eye's iris--your eye needs an ideal amount of light to see, so when it's bright outside, the iris closes in. This shrinks the pupil so that it only takes in a small amount of light. In lower light, the iris opens, making the pupil larger so that it takes in more light. Like your iris, the stomata open and close to let in the right amount of carbon dioxide.
Unfortunately, a recent study showed that with carbon dioxide concentrations increasing quickly, plant stomata are closed longer than they were 150 years ago. There are also simply fewer stomata in leaves. While this controls the amount of carbon dioxide they're absorbing, it has the added outcome of limiting the amount of water released into the air from plants. Over time, this could add up to some significant change--but it's a little early to tell for sure what the impacts will be.
It's kind of amazing to see how changes in carbon dioxide emissions have such far-reaching impacts beyond the one we hear about every day--global warming. Luckily, we have plenty of ways to work on global warming and curtail carbon dioxide emissions, such as cement that absorbs carbon dioxide as it hardens, castles that scrub CO2 from the air, and solar power concentrators that generate 1500 times as much energy as regular solar cells, reducing our dependence on fossil fuels.
What's your favorite way to ditch carbon dioxide?
This started as a reply to Bryan's comment on the Freaky Frogs post, but it quickly turned into its own blog entry...
Here's Bryan's comment:
I thought the whole BPA freakout was an interesting look at how we think about environmental and personal contaminants like this. People seemed to get all up in arms about BPA in water bottles and bought tons of new plastic or aluminium vessels to replace them. But that switch over raised some questions for me.
Where did all those old bottles go? In the trash?
How much energy does it take to make those aluminium bottles? Is it lots more than the plastic ones?
How many bottles can you own before it'd just be better to use disposable paper?
Courtesy US Government
And my response...
It took some searching, but I did find one article discussing a life cycle analysis from Australia which showed that, in a comparison between aluminum, stainless steel, and plastic, plastic has the smallest carbon emissions footprint, uses the least water, and produces the least manufacturing waste. However, it was unclear whether this comparison included recycled metals in its evaluation. Steel and aluminum are 100% recyclable (vs. plastic, which loses quality every time it's recycled), so over time and on a large scale, their use would lead to less material waste.
Courtesy Matthew Baugh
It's also interesting to note that recycling metals uses significantly less energy vs. what it would take to smelt "new" metal. To paraphrase this reference, recycling steel and aluminum saves 74% and 95%, respectively, of the energy used to make these metals from scratch. As it turns out, we recycle about half the steel we use in a year in the US, and so almost all the steel we use contains recycled content. In contrast, we recycle just 7 percent of the plastic we use.
And then there's glass--we have lots of options, really.
Courtesy Ivy Main
I can't speak to how much material was wasted when people discarded all those bottles (I think I recycled mine?). Personally, I do think that making reusable bottles in general uses less energy than is needed to make all those disposable plastics and recycle them--at least in terms of lifetime footprints. Of course, when it comes to a strict comparison between reusable bottles, switching to a new bottle will always consume more energy than just sticking with your old one.
Unfortunately, it turns out that most plastics, even the ones labeled BPA-free, leach estrogen-mimicking chemicals. So if you're looking for a long term solution, it may be best to just avoid plastics altogether. This does seem to be one of those cases where we have to consider our own health vs. the environment and pick our battles wisely. If people want to switch once to avoid health problems, at least they're still sticking with reusable bottles. Readers, do you agree?
Of course, it would be great if choosing a water bottle were the only drinking water issue we faced. The other day I read about a study by Environmental Working Group, which found that the carcinogen chromium-6 contaminates tap water throughout the US. Are we exposing ourselves to this toxic metal by drinking tap water instead of pre-bottled water? Or is chromium in the bottled water, too? What about other unregulated pollutants in our water?
I guess my point of going into all this is that it's complicated to make these decisions, and we'll probably never be able to avoid every single toxic substance. But does that mean we shouldn't try to make drinking water safer?
For now, I'm gonna stick with the steel and aluminum bottles that I already have and try to get the most out of them. Luckily, I live in the Twin Cities, which don't rate high on EWG's chromium map. Every day, I learn more about my health and the health of our environment, and hopefully by searching, I'll find a direction that hits on a fair compromise.
We've written about freaky frogs on the Buzz Blog before, but some recent news may shed new light on our abnormal amphibians. Until recently, researchers thought that atrazine, an agricultural pesticide, was the sole cause of sexual deformities in frogs. Unfortunately, it's not so simple.
Courtesy Mike Ostrowski
An ecologist at Yale University, David Skelly, sought to test assumptions about atrazine by studying the frequencies of frog deformity in different land types--agricultural, suburban, urban, and forested. Skelly expected to find the highest rates of deformities in agricultural areas, which would be consistent with atrazine being the main cause. Curiously, he found the highest rates of deformity in urban and suburban areas--places we wouldn't expect to find much atrazine. So what's going on?
It turns out that what makes atrazine so dangerous is that it mimics estrogen and binds to estrogen receptors in frog cells. Because estrogen impacts sexual development and function, so too does atrazine. But atrazine isn't the only estrogen-mimicking compound out there--there's a whole class of chemicals that mimic estrogens, including those found in birth control pills and plastics (BPA). And these chemicals are found in droves in cities and surburban areas--they're flushed into the sewage, but aren't filtered out during water treatment.
So why do we care? Besides the fact that frogs are just awesome little creatures and important parts of their food webs, they have something in common with humans--estrogen receptors. The same chemicals that impact frogs can impact us. So how do we humans keep our sexual development and functioning intact?
Skelly had a great idea to filter this stuff out of the water at the treatment plant, so that it won't get into our bodies from drinking water. He also suggested that regulatory changes would help so that when new chemicals are developed, they're scrutinized for unintended side effects. And of course, we can make choices that reduce our exposure, such as by buying BPA-free plastics, or using stainless steel and glass containers. And of course, increased awareness is always a good idea.
Do you take extra steps to avoid things like BPA? What are they?
We've probably been debating the virtues of urban areas since humans gathered in the first cities thousands of years ago. But one question we probably haven't explored much is how we can prepare our cities for climate change.
Climate and sea level have changed slowly throughout humanity's history, and we've been able to adapt. Until quite recently, humans either didn't build settlements in risky areas, or the ones they built (say on floodplains or near a sea shore) were temporary and easily moved or abandoned.
Now that we face accelerating and more extreme changes in the next 100 years, we also have some very permanent structures (and infrastructures) in the riskiest of places. Over 100 million people live in areas likely to be underwater by 2100. And even landlubbers face the challenges of more frequent extreme weather events--heavier rainfalls, droughts, etc.
Courtesy John Polo
Luckily, engineers are already beginning to plan for these changes as they retrofit and build new buildings and infrastructure. Often, these engineers are ahead of city building codes and have trouble persuading property owners to invest in addressing threats that lie in the future. But isn't it better safe than sorry? Maybe we could build cities so strong that climate change barely bothers us.
And even luckier perhaps is that cities are hotbeds of innovation and creativity. We could see the efforts of these engineers as just another example of urban virtues. More people mean more ideas and more resources devoted to the cause. And in our rapidly changing world, we need that teamwork more than ever.
Courtesy miss pupikA couple weeks ago I posted a link to a project in which Dr. Patrick Wheatley was soliciting donations of hair for geochemical research. Intrigued, I contacted Patrick to ask him more about the hair project.
Me: What do you look for as you test the hair?
Patrick: I'm looking for changes in the ratios of isotopes in various elements. I hope to tie the changes in isotopic ratios to differences in geography, either through differences in the isotope ratios of local water supplies or fundamental deferences in the geology of the region where the hair was grown.
Me: How do those isotopes get in our hair in the first place?
Patrick: They are incorporated through our drinking water or diet.
Me: What will your findings help scientists do or understand? Is there a practical application for this research?
Patrick: This research is driven by a possible forensic application, knowing the past whereabouts of victims of crimes (perhaps dead and unable to talk about where they were or perhaps held in a secret location) or suspects of crimes (maybe unwilling to talk about where they have spent time recently). There are also possible medical applications.
You can still send hair in for the project. More information can be found at the project's website.
Courtesy Mark RyanResearchers in Japan are studying the wing structure of dragonflies to help improve how micro wind turbines perform during high winds. Micro turbines are small, affordable energy converters that can be used in both urban and rural settings where giant turbines would be too expensive, too large, and too impractical. Micro turbines can be set up relatively easily in configurations of a single unit or as a bank of several units, and the energy generated can be stored in batteries.
They work on the same principle as the large turbines, but can generate power in wind speeds as low as 4 or 5 miles per hour. One fallback, though, is their generators can get overloaded when hit with high storm winds, producing more energy than the system can handle. Large turbines solve this problem by tilting their propellers - either by computer or otherwise - and adjusting their rotation speed. But that kind of technology just isn’t affordable with micro turbines.
That’s where studying dragonfly wings comes in. Aerospace engineer Akira Obata of Nippon Bunri University in Oita, Japan wondered how dragonflies were able to remain stable in flight at low speeds. He placed a plastic model of a dragonfly wing into a large tank of water laced with aluminum powder and videotaped the flow patterns. He noticed that as the water flow slowed down vortices arose on the wing’s surface that allowed the water to pass over the wing at the same speed, thus keeping it stable. But when water flow sped up the wings aerodynamics performance decreased.
So, Obata developed an inexpensive paper micro turbine with similar “dragonfly wing” bumps on its surface and it did just as he hoped. When air speeds flowing over the turbine wing increased between 15 and 90 mph, rather than speeding up its rotation and overwhelming its battery, the micro turbine curved into a conical shape that stunted rotation and kept power generation low.
Leigh and I are gearing up for another trip to the ice. We are scheduled to leave the states on January 29, arrive in New Zealand on January 31, and head further south on February 2. We’ll only be on the ice a short time for this second deployment of the field season, with the primary goal to recover the GPS units we set out in November. We will also be challenged with finding a suitable landing site higher on the glacier, in the catchment basin, above two subglacial lakes. Leigh, Gordon, and Peter tried to place those monitoring sites back in November along with the rest of our units but were unable to find a safe place to land.
We’ll be meeting up with Gordon, Peter, and Mike, along with another graduate student, Nora, who will already be waiting for us in McMurdo.
We’re looking forward to another great trip! In the meantime, make sure you check our YouTube page and photos from the November trip.
If you're a total Buzz nerd like JGordon, you may have noticed a number of posts with the tag "Future Earth" over the last couple of years. They started when the folks here at the Science Museum of Minnesota began researching a new permanent exhibit called Future Earth, opening Fall 2011 at SMM. This exhibit will ask, "How do we survive and thrive on a human-dominated planet?"
This is a different question than we're used to asking, but it's a vital one. Understanding the answer means studying more than just global warming, rising sea levels, and population growth--we also have to think about energy production, agriculture, retreating glaciers, transportation, hunger, poverty, development, and the list goes on. It turns out that because all of these issues are interrelated, we can't study or address any one of them in total isolation.
This new way of understanding is what inspired the Future Earth exhibit. Future Earth will look at environmental issues with a fresh perspective, explore the ways we study and understand our impacts on the environment, and shed light on projects that offer innovative solutions to complex problems, such as this one we hope to implement at Science Museum of Minnesota. The goal is to foster understanding, hope, and action.
Future Earth is part of a larger effort taking place at SMM, the University of Minnesota's Institute on the Environment, and a team of other institutions called the Future Earth Initiative. Funded by the National Science Foundation, FEI aims to raise awareness and offer workable solutions for life in a human-dominated environment. Given adequate time and resources, these solutions could help reduce our negative impacts on the environment while providing us all with the energy we need to live. Think of it as saving two birds with one…thing that you save birds with…
(I doubt you are as big Science Buzz fans as I am, though. Do you have a large, Party of Five-style poster of Liza, bryan kennedy, Artifactor, mdr, Thor, and Gene hanging in your room? Didn't think so.)
Anyway, despite what we might have said, it turns out that eating bugs may in fact be a good idea. But it's a good idea that's never gonna happen. (When I say "never," I mean "not in my lifetime, so as far as I'm concerned, 'never.'")
See, there are lots of folks who eat bugs (it's called entomophagy). And it's not all Fear Factor-style disgustingness—the insects are often cooked and flavored, and, you know, I'm sure they're fine. Like Corn Nuts.
But there are a lots more people who get their protein from eating larger animals, like cows and pigs and chickens and turkeys and stuff. And for a long time some people ate cows and pigs, and some people ate insects, and the world spun along just fine.
Then, not too long ago, people started to realize something: raising enough cows and pigs and things to feed billions of people has a tremendous negative impact on the environment. You have to feed each animal many times its weight in plants before it grows to full size, and all the while its pooping, peeing, and farting. And before you start complaining about how you're too young to read "pooping, peeing, and farting," let me say two things. 1) The alternative was to write "defecating, urinating, and flatulating," and you are too young to read that; and 2) animal poop, pee, and farts have a huge environmental impact.
When animal waste leaks into water sources, it can make them unhealthy to drink, and toxic to live in (if you're the sort of organism that lives in the water. And the various gases (like methane, nitrous oxide, and carbon dioxide) emitted by animals and their waste are a major source of global warming.
So there. It turns out that those of us who eat meat are straining the environment quite a bit.
But what about all those edible bugs? How do they fit in?
Well, a group of scientists from the Netherlands just published a report on that very thing. They compared the emissions of common meat animals to those of a variety of insects, and found that the world would probably be better off if we raised and ate bugs instead of cows and pigs.
See, insects are able to turn the food they eat into protein much more efficiently than cows and pigs, because insects' metabolisms don't constantly burn fuel to maintain a regular body temperature (like the metabolisms of cows, pigs and people do). In the end, for the amount of mass they build, insects produce less greenhouse gases than pigs, and way less than cows. The insects' production of ammonia (a source of water pollution) was also much less than cows and pigs. The long and the short of the research is that if we were to have farms raising delicious mealworms, house crickets, and locusts, we could reduce our greenhouse gas emissions significantly.
But I don't have high hopes for any of that; it's hard to imagine seeing insect-based food items on the shelves any time soon. Here's hoping though, right?
You know what I think makes humans unique? Our ability to solve problems. Ingenuity. Our can-do attitude. Throughout history, if we found a problem, we sought a solution. Too cold at night? Fire. Killing a mammoth with your hands too deadly? A team of spearman. Flash forward thousands of years and our problems became more sophisticated. Horse and buggy too slow? Automobiles. Candlelight not bright enough? Light bulbs. Washing laundry and dishes too tedious? Washing machines and dishwashers. Typewriters cramping your style? Computers. Computers cramping your style? Android phones. (Have you caught my drift? Good.) Now, some of our solutions are becoming new problems. Cars and electricity emit pollutants and greenhouse gases. Washing machines and dishwashers are using too much water. Computers and cell phones require the mining and eventual disposal of toxic metals. Once again, it’s time for some good ol’ human problem solving.
Courtesy urje's photostream (Flickr)
Sarah Hobbes and her collaborators identified a problem: we aren’t doing enough to reduce our household ecologic footprints, especially regarding carbon. Now, they’re working on a solution by researching what influences families to change their living habits and minimize their footprint. This past Sunday’s edition of the Star Tribune covered Sarah’s research story (the Buzz’s own Liza was even quoted!). Sarah Hobbes is an ecologist at the University of Minnesota and a resident fellow at the Institute on the Environment. Her research project doesn’t take place in a lab, but rather in peoples’ home – including the St. Paul house Sarah shares with her husband (also a University of Minnesota ecologist) and two children. The research team uses a 23-page survey to understand what kind of ecological footprint Ramsey and Anoka county homes are leaving. (Btw, kudos to those of you who already completed the lengthy survey! Science really appreciates people like you.)
Some of the initial results aren’t surprising: While most of us really do care about the environment,
“For most families, cost and convenience are more important than concern about the environment. People in the suburbs tend to use more fertilizer than those in the urban core. People with bigger houses and bigger families had a bigger carbon footprint, as did people who drove farther to work.” (Star Tribune article)
But what’s most interesting is that competition really gets us going. That is, respondents were motivated to reduce their ecological footprint after they compared their own rank to their neighbors’. Larry Baker, a project collaborator, stated,
“We expect that attitudes will drive 10 or 20 percent of the carbon emissions… If we could reduce energy use by 20 percent, that would be a huge benefit.” (Start Tribune article)
No kidding! That would be fantastic!! The full survey report hasn’t been published yet, but I’m sure looking forward to the recommended solution.
Want to know your ecological footprint? Try out this online Ecological Footprint Quiz.