Friday, November 30, 2012

Global Climate Change: Thawing of the Arctic Tundra

The above is a great short video about the effects of the warming planet on Arctic tundra.  Tundra by definition is ground that is permanently in a frozen state.  During the short and few summer months, tundra only thaws on the surface.  Deeper down however, the ground remains frozen year round.  This only allows for small shallow rooted plants to grow and prevents larger plants such as trees from ever taking root into the frozen ground.  The constantly frozen ground also does not allow plant materials to decay once they die.  Dead plant materials simply die and other plants grow on top of them.  This causes a thick accumulation of dead, un-decayed plant materials to pile-up, forming peat.  The great expansiveness of peat in Arctic tundra is a gigantic holding place for a huge amount of carbon dioxide.  The carbon dioxide simply remains locked up in the peat because of the cold and frozen conditions.  Recent warming of tundra peat however has caused some thawing and therefore allowing decay to take place in this peat.  As the decay takes place, carbon dioxide that was held in the peat is released into the atmosphere contributing to increased global temperatures.  Anyway, check out the above video for a short look on a scientific experiment and some of the potential effects of a warming climate.

Monday, November 26, 2012

Huricane, Superstorm, Frankenstorm Sandy... What Made This Storm So Bad

Watch Inside the Megastorm on PBS. See more from NOVA.

The science and story behind the development of Superstorm Sandy is fascinating.  The above video does a great job of explaining the development of this storm and how so many different weather elements came together to make this storm so bad.  The combination of a hurricane, absence of the Bermuda High, higher than usual ocean temperatures, a Nor'eastern storm, high pressure of the coast of Greenland, an adjusted jet stream, and the storm making landfall at the full moon high tide all came together to make this frankenstorm.  A hurricane or nor'eastern storm are bad enough, but the combination of these two along with everything else made this storm devastating.  Though Sandy was quite a dramatic weather event, the above video gives a great education on weather in general.  The big question now is, will superstorms like Sandy become more common in the future?  In the next 100 years temperatures are expected to warm by about four degrees which would likely increase the number and intensity of storms throughout the world.  Are storms like these a preview of what is to come in the future?

Friday, November 23, 2012

Thanksgiving and the Food Pyramid (or Choose My Plate)

The average Thanksgiving meal is about 3000 calories, or about one and a half days worth of calories.  The average American eats about 4000 calories or more on Thanksgiving day, about twice as much as what is recommended daily.  Of course, everyone is talking about all the extra calories eaten during Thanksgiving but I want to talk about how the average Thanksgiving meal lines up with the latest food pyramid.  The latest food pyramid is actually a plate called Choose My Plate and can be found here.  To do this we must first identify what actually is found in an average Thanksgiving meal.

An Average Thanksgiving meal
Turkey: 8oz.
Stuffing: 1 cup
Green bean casserole: 1/2 cup
Mashed potatoes and gravy: 1 cup
Cranberry sauce: 1 slice
Sweet potatoes: 1/2 cup
Pumpkin pie: 1 slice
Total calories: about 3000

The above meal contains about 1 and 1/3 times the recommended daily intake of protein, at most 1/5 the daily recommended intake of fruits and veggies, about two times the amount of recommended carbohydrates, and the absence of healthy oils and dairy products.  So pretty much, the typical Thanksgiving meal is extremely carb and protein heavy.  The bad thing about carbs is that they are less filling than protein and oils or fats, which means you can end up eating a lot more of them.  So it is possible that the reason there are so many carbs in a typical Thanksgiving is because they are less filling, so people just end up eating more.

We won't even go into how to calculate how many hours of exercise it would take to burn these extra calories off, which is about 6 hours.  But hey, this is only one meal a year so its not something to really beat yourself up over, especially if you are eating healthy on a regular basis.

Tuesday, November 20, 2012

Echinocereus sp.: The Hedgehog Cactus

Echinocereus engelmannii
The hedgehog cacti are probably my favorite group within the cactus family.  I find their forms, including shapes and spines very interesting.  Their flowers come in an assortment of beautiful colors ranging from pink to red to white to yellow to purple.  Flowers also survive quite a few more days than other cacti flowers.  The scientific name for hedgehogs is Echinocereus.  Fittingly, echino means "hedgehog", and cereus means candle.  I suppose the individual stems may look somewhat like a hedgehog or candle, but I consider them to look more like a cucumber standing upright.  The stems of hedgehog cacti most often are clumped together but with several species they are individual or forming mounds.  Hedgehog cacti are common throughout SW United States and NW Mexico surviving in the low deserts to the high mountains.  The full extent of hedgehogs ranges from South Dakota to Central Mexico.  Identifying these cacti can be a little tricky at times and knowing flower color as well as spine density, length, and coloration is essential.  Even within species there can be considerable variation of traits.  For this reason, botanists have been confused and arguing over classification of different hedgehog cacti for decades.  As time goes on, these botanists seem to discover more and more species, or identify new species out of already existing groups.  Hedgehog fruits are also typically very tasty and Native Americans would eat the fruit as they came across them.  The cacti do not seem to produce a lot of fruit though, so I suppose they were eaten more like a snack.   
Echinocereus coccineus

Echinocereus engelmannii

Friday, November 16, 2012

Joshua Trees, Ice Age Sloths, Extinction, and Climate Change Today

With the end of the Ice Age, the giant Shasta ground sloth became extinct in our American Southwest deserts. This extinction happened as a result of the warming of the continent and invasion of humans into the land 13,000 years ago.  Today, the sloth is long gone, but the consequences of its extinction are still being seen to this day.  The Shasta ground sloth was intimately intertwined with every organism they ate, use, or associate with.  Of course, all organisms that inhabit this earth are intertwined in the same way with all the organisms they eat, use, and associate with both directly and indirectly.  This can be extended to show that all organisms are in one way or another connected.  If one organism is removed from an ecosystem, such as the ground sloth, every other part is affected and must adjust their life accordingly.

Unfortunately, not every organism is able to adjust to every change in an environment.  Such was the case of the Shasta ground sloth.  As the climate warmed, plants that inhabited the Southwestern deserts changed, changing the sloths food sources.  As food sources changed, the sloth could not adjust and as a result became extinct.  As a result, the plants and animals affected both directly and indirectly by the sloth had to adjust to "life after the sloth".  For example, the Joshua Tree was a major part of the sloths diet.  At first it may seem that extinction of something that is eating you might be a good thing.  At first, I could guess, the Joshua tree might have benefited greatly by the absence of a giant animal consuming it.  Long term however, the Joshua tree suffered greatly and continues to suffer to this day.  As the sloth ate the Joshua tree, of course this injured the plant.  However, as the sloth ate, it also consumed the Joshua tree seed which would pass all the way through the sloths digestive tract without being damaged.  Once passing though the sloths digestive tract the seed would find itself in a moist pile of fertilizer, which is an extremely ideal location to find yourself if you are a desert seed in desperate need of moisture and nutrients.  

With this association of the sloth and Joshua tree, the sloth benefited with food by eating the tree.  The
Joshua tree made a trade-off though, being damaged by the sloth as it was eaten, but benefiting from the sloth into the next generation.  The sloth aided the success of the Joshua Tree by likely aiding germination and by carrying the seeds to new locations up to ten miles away.  After the extinction, and up to the present day, only desert squirrels and packrats move Joshua tree seeds today, and only at a pace of about six feed per year.  As a result, the Joshua tree cannot adjust its range anywhere near as quickly as it could before and its range has been shrinking for over 10,000 years now.  How do we know all this?  Scientists in the Southwest have examined caves where sloth dung which tells us what the sloth ate.  Ancient packrat middens also have been examined which tell us where the Joshua tree was and when over the last 10,000 plus years.

With the ability to only change their range six feet per year, the Joshua trees range will continue to shrink in coming decades.  Currently, the climate is warming far to fast for the Joshua tree to keep pace.  This does not mean however the Joshua tree will go extinct.  It will be able to survive in cooler high elevation locations.  As the range of the Joshua tree is reduced however, organisms dependent on it will have to adjust.  For example, many species of rodents are dependent on moisture from the tree during times of drought.  These organisms access water from the tree simply by chewing through the bark to access water.  With the trees gone however, there will be far less water available to support rodents.  And so we see the continued consequence of the extinction of the sloth.

Tuesday, November 13, 2012

How to Make Sauerkraut

Every fall I start thinking about making my own sauerkraut.  Making your own sauerkraut is really a very simple process once you are familiarized with the steps required.  The process is very similar to making kimchi but kimchi is much more complicated in regards to spices and different steps, and for that reason I prefer to make sauerkraut.  I have written about the process before on this blog (How to make sauerkraut) and will summarize briefly here:
  1. Shred your cabbage.
  2.  Thought mix shredded cabbage with sea salt by hand.  The salt will draw the liquid out of the cabbage.  Do this in a crock or straight walled jar.  There is not set ratio of salt to cabbage, this is simply a taste preference.  You do need enough salt though to draw enough water out of the cabbage. 
  3. Weigh and press down the cabbage so it is below the liquid mark.
  4. Cover the entire container so dust will not contaminate the process.
  5. Wait until bubbling stops before removing weight to taste sauerkraut.  Press down on the weight daily to push out gas bubbles given off by fermentation. Bubbles generally stop before two weeks.  
  6. Sauerkraut can be stored for weeks at or below room temperature if it is submerged below the water level.
 And that's the basics of making sauerkraut.  The first time is most definitely the scariest time.  But after that it gets pretty easy.  Here are some tricks to making sauerkraut:
  • More salt will slow the entire fermentation process significantly but will preserve the sauerkraut for longer periods of time.  It takes very little salt though to make sauerkraut and to preserve kraut with low salt, simply place it in the fridge.  Adding more salt and refrigerating after bubbling has stopped a few days is the safest way of making sauerkraut for the first time.  After doing this you can experiment with adding less salt.
  • If temperatures are going to higher, say above 75 degrees add more salt.  This helps control yeast and microbial growth.
  • Lower temperatures require less salt because the lower temperatures help control yeast and microbial growth. 
  • Different temperatures and amounts of salt will change the flavor of the sauerkraut.  Play around with these in different batches to see what tastes best to you.  I prefer sauerkraut when average daily temperatures are in the 60's and with a low salt content.
  • You can add any seasoning or vegetable to your batch as long as it doesn't add to much sugar or starch.  For example, peppers, onions, garlic, radishes, and ginger can all be added.
Some things to watch out for:
  • If your batch of kraut goes on bubbling for a long period of time after the initial two weeks, throw it out, it has gone bad.  Do the same if it stops bubbling and then starts again.
  • The sauerkraut should be a pale color unless you add veggies that have color in them like purple onions or purple cabbage.  Then the sauerkraut will take on a purple color.  If the sauerkraut takes on an off color or is brownish it has gone bad and you need to get rid of it.
  • If the sauerkraut is slimy or smells weird it has gone bad.
  • Any sauerkraut exposed to the air and not submerged under the liquid will go bad.  

Friday, November 9, 2012

Easy Enzyme Experiments Anyone Can Do

Three catalase enzyme experiments.  More bubbles demonstrate more catalase enzymes. On the left, catalase extract from beef muscle, middle beef kidney, right beef liver.  Liver has the most catalase, second most is kidney, and muscle has hardly any at all. 
The easy enzyme experiments have been some of the most popular posts on this blog so I'll be posting a summary of them today.  These experiments really are easy enough for nearly anyone to do and to use to demonstrate the amazing work these molecules do.  Unfortunately, most enzyme experimentation is extremely difficult and must be done in a science lab.  I have come across several though that are rather simple and I am always looking for more simple enzyme experiments to post here.  

Enzymes, you can't see them, but you can't live without them.  Some scientists have seen the rough outline of larger enzymes using scanning electron microscopes, but they still haven't actually seen one.  In-fact, no one has ever seen one, they are simply too small.  So how do we know they exist?  Molecular scientists use special complex scientific techniques to determine the shapes and structures of enzymes without actually looking at them directly.  More practically though, we see proof of enzymes every single day, every single second.  The very fact that we, or anything else is alive, is owed to these amazing molecules.  Without these molecules hardly any of the chemical reactions that take place in our body would ever happen.  And without these chemical reactions, life would never happen.  All of the cells in our bodies are loaded with dozens of enzymes of different types, all making life possible.   A few of these enzymes are easy for us to extract and observe the work they do very clearly.  Anyone can do these experiments with some basic equipment, even in a kitchen.  

One of the most common and easiest enzymes to work with is catalase.  This enzyme is found in potatoes, spinach, and liver in high concentrations.  To extract it all you have to do is blend some of these materials up with some water.  Catalase functions to convert hydrogen peroxide into water and oxygen.  This protects the body from the harmful effects of hydrogen peroxide, which is commonly produced as a metabolic by-product. You can conduct your own catalase experiments simply by adding hydrogen peroxide to your extract.

Another great and easy enzyme experiment is that of rennet and cheese making.  Cheese is actually made by the enzyme called rennet.  You can buy rennet off of Amazon, follow the directions that come with the packet, and make cheese in the process.  Without rennet, we would only have a few different types of cheeses.  

A very practical enzyme to our digestion is protease.  Without this enzyme it would be impossible for us to digest protein of any kind.  Protease can be found naturally in fresh pineapple, or in meat tenderizer (which contains protease found in pineapple).  The reason fresh pineapple cannot be used in making gelatin is because the protease in the pineapple digests the gelatin protein, preventing the gelatin from solidifying.  Pineapple or mango protease are also placed in pills that aid digestion.  

Lastly, amylase is another protein that is important to carbohydrate digestion.  By mixing ground-up crackers with spit (where amylase is typically found), you can actually witness how your spit digests carbohydrates.  

If you know of other simple enzyme experiments, please let me know.  

Monday, November 5, 2012

Barrel Cactus Part 2

California barrel cactus, Ferocactus cylindraceus.
Barrel cacti are kind of as their names imply, barrels full of water.  The problem is, the water isn't just hanging out in the cactus like a big glass of water.  The water is stored inside of the cells that fill the interior of the cactus.  The best way to get this water is to eat the tissue, though it won't taste very good and probably will make you sick.  The thick layer of hooked spines will also deter any person or animal from easily accessing this water though.  In drought however, the barrel cacti is one of the best sources of water for desert animals there is, that is, if they can get through the spines.  Small animals like rats, chipmunks, or mice can avoid spines by burrowing underground slightly to where there are no spines and then eating up into the cactus.  I have actually found a few barrel cacti that have been entirely hollowed out by rodents, yet have there skin and spines fully intact.  Larger animals such as deer have no such luck though accessing moisture from a standing barrel cactus though.  The spines become just too big of a deterrent.

Red spines of the barrel cactus show up after being wet by rain.
Fortunately, for larger mammals the barrel cactus has a fatal flaw.  As a barrel cactus grows it generally leans towards the southwest, which is the direction from which the most intense sun comes from.  Nearly all barrels lean to the southwest, just as a compass always points north, thus the common name compass barrel.   It might seem that leaning in the direction of the brightest sunlight might mean the cactus is trying to gather as much sunlight as possible.  This is however the exact opposite of what it is doing.  With the top of the cactus pointing directly at the most intense sun, spines at the top actually shade out much of this light and all sides of the cactus actually avoid this direct sunlight.  The sides however gather the most sunlight from the sides, as the sun comes up or goes down, when the sun rays are less intense and therefore less damaging to the cactus.  Pointing tops towards the most intense sunlight is therefore actually a protection mechanism, rather than a gathering mechanism, against intense sunlight.
A barrel cactus that fell over due to leaning towards the southwest.  Even though this cactus fell over, it continues to grow.
Leaning is an important adaptive strategy of the cactus, but is this strength also lays a huge weakness.  As the barrel cacti grows and leans it becomes very off balance.  Older, large cacti will often simply fall over.  Oddly, even when the cactus falls over it will continue to live and grow as it lives laying on the ground.  Once the barrel cactus falls over, the underside of the cactus is exposed which is unprotected by spines.  Large mammals will often start eating the barrel from this unprotected portion during drought.  
Flower of the California barrel cactus Ferocactus cylindraceus.

Friday, November 2, 2012

Barrel Cactus Part 1

Compass Barrel cactus
The barrel cactus is one of the most common cacti in the Southwest.  There are four different species common to this area of the country, the most common of which are the compass barrel and the California barrel.  It can be extremely difficult to distinguish between these two common species of barrels.  In southern Arizona, such as around Tucson, the compass barrel is the most common of the two cacti.  In central Arizona such as around Phoenix, southern California, and even into the depths of the Grand Canyon the California barrel cactus is the most common.  Their ranges overlap in central Arizona and their similarities are pretty extensive.  Without closer investigation you may not be able to determine what specific species a particular barrel is, there are however a few differences that may help in identification.  First off is shape.  Of course, barrel cacti are all sort of barrel shaped.  The compass barrel is a little more wide and plump than the California barrel.  The California barrel  is a little skinnier.  The second way to distinguish between the two is by looking at the spines.  Both have very interesting spines which are often red colored.  This red coloration gives a sharp contrast to the dark green of the cacti's body, especially after a rare rainfall.  Both cacti also have flattened central spines that have a ribbing pattern on them.  The central spines are also hooked, giving both cacti another common name of fishhook barrels.  Compass barrel cacti spines are however considerably more hooked than California barrels.  Compass barrel central spines are a full "fishhook" shape and were in-fact used as fishhooks by some Native Americans.  California barrel central spines are closer to a 90 degree curve than an actual fishhook.  These are the best ways, though not necessarily foolproof ways of distinguishing the two while out in the desert.

In our next post we will talk about the leaning habit of barrel cacti.
California barrel cactus front left of picture.