Monday, January 30, 2012

White Tank Mountains Bajada Trail Nature Hike

In our last post we discussed hiking the South Trail in the White Tank Mountains.  Now we'll move on toward a short section of the Goat Camp Trail and finally onto the Bajada Trail.  The end of South Trail and this section of Goat Camp Trail is quite interesting for those who like to examine landscape patterns...

Most of the South Trail is rather straight and smooth, but close to Goat Camp Trail is sort of dips down a little and you will notice the surface becoming a lot more rocky and rugged.  This is the second alluvial fan in the bajada.  Typically this type of surface is closer to the mountain then the previous surface we discussed, so this bajada is sort of upside down.  I suspect this odd configuration of alluvial fans is a result of this second alluvial fan resulting from a large avalanche or debris flow that came out of Goat Camp Canyon.  The abundance of disorganized rocks and rugged surface could be in indication of an ancient avalanche.  The dry wash at the beginning of the trail also is responsible for eroding away the smaller sediments and leaving behind the heavier rocks and a rugged surface.  The major plant cover is brittle bush which prefers rocky and often unstable soil surfaces such as this one.  Palo verde and jojoba also seem to like these soil conditions.  There are also a decent number of cacti present and a few bursage in patches, indicating there is likely some caliche in the soil. 
This rocky and rugged soil alluvial fan surface is more typical higher upslope.
After hiking through the rocky and rugged area and heading uphill slightly on the Bajada Trail from Goat Camp Trail, the trail returns to the same alluvial fan most of the South Trail covered.  So same soil conditions and same plants as most of the South Trail.  But here I want to point out the abundance of saguaro cacti, the icon of the Sonoran Desert.  Saguaros are more abundant here than just about any other area west of Phoenix.  The reason for this is, as mentioned before, the soil conditions and abundance of triangle-leaf bursage.  In addition to that, this area receives about nine inches of rain annually and is relatively free of freezing temperatures.  In areas east and north of Phoenix there are many populations of saguaros that are denser, as a result of greater rainfall, upwards to about 12 inches annually.  These higher rainfall areas are also higher elevation and therefore more prone to freezing which can damage saguaros by causing their arms to droop towards the ground.  Very few saguaros in this area have drooping arms in the area of these trails due to the lack of freezing temperatures.  There are a few though.  Nearly all of the Saguaros in this area are mid to older aged, you can tell the age of a saguaro simply by its height and presence of arms.  The taller a saguaro is the older it is, and more arms usually indicates older age also.  There are not a lot of young saguaros, which tells us there isn’t much reproduction going on, and if reproduction doesn’t increase in the next 50 or so years the population will decrease significantly.  There is also a lack of very old cacti, which indicates that the population of saguaros was once much smaller than it is now.  While I suspect the saguaro population may be decreasing due to lower rainfall during the past two decades, a few years of good rain could easily allow for the establishment of many young saguaros and cause the population to bounce back.  So there is no immediate reason for us to fear the disappearance of the saguaro from the White Tank Mountains during our life time.
A saguaro cactus with a drooping arm.  Typically, arms drooping down like this means the cactus was damaged by freezing temperatures. 
And this concluded the White Tank Mountains South to Goat Camp to Bajada Trails tour.  Hopefully it was interesting or helpful, even if you don’t hike these trails yourself.  In my 150 mile hiking goal for 2012 I currently am at 15 miles.  I have a few trails I have hiked and have yet to write about and you’ll be seeing them in the near future.  Also, if you have any questions about anything pertaining to this post, or any post, let me know.  I want to make everything here on Practical Biology of course practical, interesting, and educational.  Thanks!
A crested saguaro cactus along Bajada Trail.

Friday, January 27, 2012

White Tank Mountains South Trail Nature Hike

Two Saguaro cacti in the White Tank Mountains Regional Park.
When it comes to viewing Saguaro Cacti and an unusual bajada or alluvial fan formations, the South and Bajada Trails in the White Tank Mountains  are about as easy and as they come, at least for the western portion of Phoenix, Arizona.  The trail begins at the South Trail near the entrance of the regional park, heading towards a short section of Goat Camp trail, and then to the Bajada trail, entire length about 3.5 miles and all pretty flat for some relaxed hiking.  The entire length of trail transects the bajadas, or alluvial fans, that were deposited by ancient erosion and avalanches descending from the surrounding mountainsides to the north and south of the trails and Goat Camp Canyon to the west of the trails.  Different types of deposits and differing types of drainage patterns has resulted in two major alluvial fans forming a bajada that is seemingly backwards in formation.  One of these alluvial fans though is ideal habitat for the iconic Saguaro Cacti as I will explain below.  This post will be in two parts, this first post will cover mainly South Trail.  The second post on Monday will cover mainly Bajada Trail. 
Desert dry wash along the South-Goat Camp-Bajada Trails in the White Tank Mountains.
Beginning at the South Trail trailhead near the entrance to the park, you immediately hike down into a dry wash.  This wash is one of at least a few washes that are responsible for the unusual bajada formation along the trail further along.  As most people would expect, a dry wash, also known as an ephemeral drainage, is where runoff water concentrates and flows for short periods of time following heavy rainfall.  The water only flows a short period of time because it is quickly absorbed into the loose sand in the channel where it can infiltrate very deep.  Deep in these wash sediments the water is protected from the extreme heat on the surface and is therefore a reservoir during long dry periods.  Only deep rooted plants, however, can access these reservoirs and that is why there is a concentration of ironwood and palo verde trees.  Even shallow rooted plants such as cacti and triangle-leaf bursage are in higher concentration here through, simply because there is more moisture in these washes then the surrounding soils.  Along with transporting water, washes similar to this one also transport sediments eroded from further upslope.  Washes, as they transport sediments down slope, are the major creators of alluvial fans.  Many alluvial fans were once at the end of a dry wash where the wash sort of spewed out over the surface all the sediments it transported from upslope during short periods of water flow.  Washes also are the major destroyers of alluvial fans being they erode into and carry away the sediments that compose the fans.  Because of these things, if you are familiar with the washes on a Sonoran Desert alluvial fan or bajada you can know a lot about the history of these landforms.  We will see this later on in the hike towards the end of the South Trail.
The plant community along the South Trail is mainly Cacti, Bursage, and some Palo Verde. 
Once hiking out of the wash the trail crosses onto another alluvial fan surface with a different soil type.  This soil type continues for most of South Trail.  The vegetation is characterized by shallow rooted plants, mainly cacti and triangle-leaf bursage.  This tell me that the soil is well developed, probably with a caliche horizon and maybe with a weak argillic.  Caliche is simply a rock-like calcium layer that forms about 20 inches below the soil surface in deserts and argillic horizons are deposits of clay just above the caliche.  Both layers prevent deep roots from penetrating and help shallow rooted plants become established, the most important of which is triangle-leaf bursage.  This small shrub grows everywhere along most of South and Bajada Trails and because of its abundance there is also an abundance of cacti.  Bursage functions as a nurse plant for many desert plants.  Odd as it might sound, most desert conditions are too hot, dry, and sunny for most desert plants to establish themselves without the aid of another plant.  Being bursage can establish without help of other plants, it provides the shade and slightly cooler and moister conditions required for cacti to germinate and grow under their small canopy.  The presence of bursage, along with the soil conditions, is therefore why there are so many cacti present along the South and Bajada Trails.
 To be continued Monday...

Wednesday, January 25, 2012

Do Plants Breathe? How do Plants Breathe?

Plants breathe quite the opposite of the way we breathe.  They do breathe though, and they do it through tine holes called stomata located on their leaves.
Oops, I thought I posted this on Monday.  But here you go, better late than never!

It’s common knowledge that humans and animals inhale oxygen and exhale carbon dioxide in a process called respiration.  A lot of people also know that plants do just the opposite, “inhaling” carbon dioxide and “exhaling” oxygen, in a process called photosynthesis.  As a result plants and animals cycle oxygen and carbon dioxide between each other, one producing a waste that is used by the other and so on.  Obviously, animals breath through their mouths and nostrils but the way plants breath is far less obvious.  Nothing on a plant resembles a mouth or nose in the way animals breath.  And if we look at the chemical reaction for photosynthesis and respiration we will see they are sort of opposites, or reflections, to one another.  What one produces the other consumes.  So because of the differences we should expect totally different ways of breathing between the two.

Water + Carbon Dioxide + Light → Sugar + Oxygen

Sugar + Oxygen → Carbon Dioxide + Water

Stomata are the round holes in the photo above.  This is a microscopic image of a fingernail polish peel taken from a leaf surface.  Most plants open these during the day in order to breathe.  Only cacti and agaves open them at night to breathe
The only way to find the structures through which plants breathe is by searching microscopically.  Very simply, by painting a square inch or so of a leaf with clear fingernail polish, then peeling it off and viewing it under a microscope we should be able to find the stomata, which are tiny microscopic holes through which plants breathe.  The dried fingernail polish retains the cellular imprint of the leaf surface so when viewed under a microscope every structure on the leaf surface can be seen.  On the fingernail polish peal, the stomata appears as a tiny hole with two crescent shaped cells on either side. These crescent cells are known as guard cells being they open and close the stomata in order to let “breathing” to occur or not, and to preserve water.  Stomata can be found on any green surface of a plant, but typically are located in the highest concentrations on the underside of leaves.  Location on leaf undersides prevents exposure to the sun which helps prevent excess water loss through the stomata.  

Different types of plants have different patterns and forms of stomata.  Most trees have lots of relatively small oval stomata evenly spaced all over their leaves.  Desert trees and shrubs generally have fewer stomata to conserve water.  Corn and other grasses often have more rectangular stomata organized in rows along vessels.  Cacti have relatively few round stomata located in pits, but they are huge compared to other plants.  Types and shapes of stomata generally depend on how much water a plant has available and its general physiology.  Plants with lots of stomata have lots of water while plants with fewer stomata have less water.  If you have a microscope try making a fingernail polish peal to view the stomata, it takes a few tries but after that becomes extremely easy. 

Here is a website with more details on how to do this experiment:  Stomata Experiment

Sorry, I completely forgot to update the blog on Monday.  I became so busy with writing things up for this site that I thought I posted something new!

Friday, January 20, 2012

The Newest Food Pyramid: Choose My Plate

The new food plate replaces the food pyramid.

Food pyramids have been around for about 20 years and in that time they have come a long way.  The first USDA food pyramid had a huge emphasis on eating carbs, any type of carb, and avoiding all fats no matter what type.  The pyramids suggested protein intake has also changed over time but fruits and veggies have pretty much stayed the same.  The latest “food pyramid” however has made the biggest change yet…  it has evolved from a food pyramid into a food plate.  I still like the idea of the food pyramid better then a plate, there is just something about it that makes it easy to understand.  The new food plate does make some major changes though that a huge strides towards better health based on current health and nutritional research. 

Check out the new food plate at:

This new food pyramid is now old being it has been replaced a food plate.  This food pyramid, though more complex than the new food plate, is still a very good guide to nutrition.
First off, the new food plate breaks down the food groups differently than previous food pyramids.  Old pyramids had fruits, veggies, grains, meat, and dairy food groups.  With time and greater understanding however, pyramids became increasingly complex with increased numbers of food groups.  The new plate sort of simplifies things again with fruit, veggies, dairy, grains, and the new protein group.  There is a strong emphasis in this to eat whole grains, oils, and to limit protein intake.  I think the research based simplification of the food groups is excellent.  The new food plate is not as simple to use as the food pyramids though.  With the old pyramids you could simply look at them and understand what to eat and how much.  To understand the the new food plate you must examine the food groups and their explanation online.  

I tested out their food tracker for the new plate to see how it works in real life and to see how I measure up.  The results to me were rather interesting.  I learned I ate too few grains, too many veggies, slightly too many fruits, too much oil, and slightly too much protein.  Most everything else was fine.  I have a few problems with this new plate.  First off anyone or anything that suggests you can eat too many veggies has a screw loose.  I can understand for people with weight problems why eating too many fruits might be bad due to sugar content, but I can’t believe eating too many fruits would be bad for someone with a healthy weight and moderate activity levels.  Same with healthy oils.  The new plate rightly distinguishes between healthy and unhealthy fats, solid fats being unhealthy and oils, or liquid fats, being healthy.  As long as someone has a healthy weight and is moderately physically active, consuming too much oil should not be a problem, within moderation of course.  Lastly, I have an issue with eating gluten being it irritates my digestive tract so it would be extremely difficult for someone like me to consume enough whole grains.  To be honest, I was not especially enthused about the food tracker, especially since I eat a lot of baked sweet potatoes and the tracker doesn’t even list that as a food option for entry.   Overall, I think the tracker is a very good idea and a great way for someone to learn how to eat healthy though.  I am just not sure it will work for me.  I would suggest it for anyone looking to track and change their diet.
There are a lot of good things to this new food plate and it is a positive step beyond the old food pyramids.  There still are some problems with it however as I mentioned above.  Even considering some of the negatives, anyone would do very well diet and health wise to follow what is said in this plate.  Again, check out the website, specifically the food groups ( section.  There is tons of great dietary information on the site that can help just about anyone.  So check it out and let me know what you think.
This is the original food pyramid.  While it has many similarities to the newer pyramid and food plate, it is nowhere near as healthy.  The new ones make this one look ridiculous.

Monday, January 16, 2012

Biology with a Birds-Eye View: From an Airplane Window or Google Earth

One of the last places you would expect to do biology is on an airplane.  As long as you have a window seat however, and can look at the ground you can make some pretty interesting biological observations.  For that matter, you really don’t need an airplane you could simply use Google Earth to make the same observations.  Google Earth is of course the easier and better option of the two though, but either way you can look at the ground and find out some pretty interesting things.  A birds-eye view of the ground can tell you about soils, vegetation, landforms, landscape patterns, and simply be interesting to explore.  In some of my scientific investigations I have spent a lot of time examining Google Earth images looking for vegetation, soil, land form, and land use patterns.  Aerial images truly can be a joy to search through and can yield all kinds of interesting pieces of information.  

Here are some of the things you can discover about the landscape with an aerial photograph:

Land forms: Is the landscape hilly, mountainous, flat, marshy?  Often Google Earths 3-D landscape feature will help with this.

Vegetation: Forest, grassland, desert, agriculture, swamps and all their variations can be identified with aerial photos.  

Soil: Identifying soil is difficult when lots of vegetation is covering the ground.  However, in areas of sparse vegetation such as in deserts or where agricultural fields have been cleared you will be able to identify soil color.  These colors can tell you something about how the soils developed.  Also look for changes in color in the soil across the landscape, often you will be able to identify vegetation changes that go along with soil changes.  

Drainage patterns and waterways: It can be very interesting to see how exactly water moves or drains across the landscape and how this relates to soil color where visible and to vegetation patterns.  It can also be fun to trace a waterway back to its source.

Look for other things also such as abandoned mines, farms, secluded streams, or anything else of interest.  I have searched Google Earth images for hiking trails, specific types of landforms, canyons, rock formations, and anything else of interest I come across.  I have also enjoyed tracing the path of a waterway to see how it changes with distance.  Sometimes, after exploring these aerial images you can then hike or drive through the area you explored, make sure you have legal access to the land before entering the land however.  Also, be extremely careful searching for old mines or farms which can be extremely dangerous.  Obviously you could fall into an old mine and old farms often have unmarked wells.

Friday, January 13, 2012

Black Rock Trail White Tank Mountains: Touring a Bajada

Lower alluvial fan, furthest away from the mountains, of the bajada on Black Rock Trail in the White Tank Mountains.  Cacti and bursage, shallow rooted plants characterize this part of the bajada indicating some caliche development in the soil.  Creosote, a deeply rooted plant shows that this caliche is not well developed and still allows for deep roots to penetrate it.

As for easily accessible trails, the Black Rock trail in the White Tank Mountains Park is a good one.  Crowded, but not as crowded as the nearby Waterfall Trail and the landscape is not nearly as trampled.  This particular trail has two loops, a short loop with a smooth and wide path, and a long loop which is narrower and slightly rocky.  The short loop is half a mile while the long loop which branches off and returns to the small loop is 1.3 miles.  While most hikers may find such a short and easily accessible hike sort of boring, I believe a little scientific knowledge of the area can give you some things to look for, making the hike quite interesting.  I personally would have considered this hike sort of boring if I wasn’t taking the time to examine landscape features.  But taking a little time to smell the roses, or rather examine the dirt, rocks, plants and so on, can make this boring hike quite interesting.  Looking closely, this loop is an excellent example of a classic Sonoran Desert bajada, specifically the upper to mid portions of a bajada.
First of all, a bajada is simply an aggregation of several alluvial fans.  And if you are wondering what an alluvial fan is, it is simply the sediments or dirt that is deposited on the ground by water.   Alluvial fans often make a fan-shaped landform when viewed from the air.  Alluvial fans are deposited adjacent to mountains when sediments wash off the mountain.  Several alluvial fans deposited in succession together form a bajada, and in the Sonoran Desert the further a fan is away from a mountain the younger it is.  The Black Rock Trail has a slight slope up towards the mountains.  Hiking along this slope you are hiking over very old alluvial fans which sediments were once part of the White Tank Mountains.

In the case of Black Rock Trail, there are three alluvial fans, each with is distinct soil type.  Starting off at the trail head, furthest away from the mountain is the youngest fan.  The plants indicate there is a weakly formed layer of caliche here.  Creosote is most common in this area of the trail being its deep roots do not tolerate well developed caliche layers, and therefore indicates weak caliche or an absence of it.  Triangle-leaf bursage also common to the area however requires some caliche development in the soil.  So put together bursage and creosote indicate a weak caliche horizon. 
Middle alluvial fan on the Black Rock Trail.  Characterized by shallow rooted plants such as cacti and triangle leaf bursage.  The presence of caliche in the soil favors these shallow rooted plants.
Hiking up the slight incline a short distance there is an increase in cacti, bursage, and palo verde, and a sharp decrease in creosote.  Palo verde, bursage, and cacti all seem to prefer stronger caliche development while creosote doesn’t tolerate it well.  This is the second alluvial fan, and plants with shallow roots that can accumulate above the caliche dominate this area.  Deeper rooted plants such as creosote are not able to penetrate the caliche and therefore don’t grow in abundance.

If it were just for the bajada, this trail might be at least a little boring.  But in the beginning to mid portions of the trail you pass some striking out-crops of granite.  What is striking about these out-crops is not simply that they are granite, but rather that the rocks are out of place in the bajada and that their coloration is pitch black in places.  These out-crops are sort of islands of rock surrounded by the dirt and sediments that form the bajada they pierce through.  As the bajada sediments were deposited off of the mountain these rocks remained in place, largely unmoved.  The alluvial fans and bajada was simply deposited around the rocks.  The rock formations are therefore very old, much older than the surrounding bajada.  The old age of the rock formation is indicated by the presence of the thick and very dark black desert varnish layers that color these rocks.
Granite outcropping along the Black Rock Tail.
Hiking beyond the short loop and onto the long loop the trail becomes a little rougher.  You will notice that the ground becomes increasingly rocky and more uneven.  This indicated the transition to the third and oldest alluvial fan closest to the mountain.  Here, there still may be some triangle-leaf bursage indicating caliche, but the further you go there is defiantly a shift towards more brittle bush.  Brittle bush prefers very rocky and often unstable soil surfaces, both common to this area.  There are still on this third fan a lot of cacti as well as palo verde and some ironwood trees.  The Ironwood trees seem to increase the closer you get to the Waterfall Trail, possibly a result of their deep roots accessing water that sinks deep into the sediments after if flows over the waterfall.
The upper alluvial fan of the bajada.  If you were able to see the ground you would notice that it is much  rockier and rougher than the lower two alluvial fans.  This type of soil favors brittle bush which is the shrub layer you see covering the ground here.  Cacti are still common here indicating some caliche in the soil.
As the long loop of the Black Rock Trail loops back and starts heading away from the mountains you begin your return down the bajada.  The whole trip requires at most 45 minutes or so if you go slow, and in that short period of time you can get a great tour of a Sonoran Desert bajada and the plant ecology.  Really, tours of this type don’t get any easier.  After this hike I am at about six miles of my 150 mile hiking goal for 2012.  So far so good.  I am hoping to do some longer hikes in the near future and hopefully take some big chunks out of my goal pretty quickly.  

Monday, January 9, 2012

Easy Enzyme Experiment: Protease and Gelatin

In the two beakers of gelatin above, fresh pineapple was added to the one on the left and canned pineapple to the one on the right.  The enzyme protease, present in the fresh pineapple on the left, broke down the structure of the gelatin liquefying it.  The canning process breaks down the protease enzyme so it no longer works so the beaker on the right has solidified gelatin in it

Being that enzymes breakdown molecules or digest them, enzymes are extremely important to our own food digestion.  Every living organism has enzymes within their body in order to do molecular work and we are no exception.  Plants and animals alike have enzymes, and interestingly they often have similar enzymes.  When animals eat protein, in order for them to breakdown the protein so it can be absorbed by the body it must be digested into amino acids.  Amino acids are the individual molecules that when strung together make proteins.  The group of enzymes called proteases are responsible for the breakdown and digestion of protein in the body.  Some plants, such as pineapple also have high levels of protease enzyme.  Specifically, pineapple has a protease called bromelain.  Pineapple bromelain has been utilized for all kinds of medical purposes some of which work and others of which do not.  At least to some degree, it does aid the digestion of proteins if we consume it with meat.  Bromelain also is commonly used as a meat tenderizer, in effect, it is digesting the meat before we eat it.  I have done quite a bit of reading on the internet as to why pineapple would need bromelain in it, but couldn’t come up with anything.  The only thing I can think of is that protease would probably help pineapple fight off infectious organisms.  By using fresh pineapple we can carry out a very simple enzyme experiment demonstrating the action of protease.

As mentioned before, protease digests protein helping to tenderize meat.  This is helpful in some circumstances but not in others.  For example, if you make Jello or any other type of gelatin food, adding pineapple will ruin the dish.  Gelatin makes a liquid into a solid by the action of a protein called collagen.  This is the most abundant protein in humans, composing as much as 25 to 35 percent of all our bodies protein.  It is utilized in connecting and holding things together in the body.  It is also abundant in other animals of course, and almost all collagen protein for gelatin is extracted from pork and beef skin and bone after the butchering process.  Contrary to popular belief, animal hooves are typically not used.  On the side of the Jello box it says to not add raw ginger, pineapple, kiwi, or papaya.  All of these foods naturally contain protease enzymes that would digest collagen and prevent the gelatin from solidifying.  

A basic experiment can demonstrate this:

Fresh pineapple
Jello or gelatin and supplies for making it

1.  Make your gelatin as directed on box.

2. Pour liquid gelatin into multiple containers for different treatments.  For example: 1 container as a control where nothing will be added, a second container where chunks of fresh pineapple will be added, and a third or more where other test items might be added.  Other test items might be canned pineapple, the other fruits mentioned above, or anything else you want to test.

3. Add the fruit to the different containers and let the gelatin solidify.

After the gelatin is supposed to solidify you should find that the gelatin container where nothing was added has solidified.  The container where fresh pineapple was added should still be liquid.  The liquid indicates that protease from the pineapple digested the collagen protein preventing the gelatin from solidifying.  If you add canned pineapple to another container the gelatin should solidify.  This is because heating in the canning process breaks down, or denatures, the protease enzyme in pineapple.  Try other fruits and see what happens or see if cooking fresh pineapple has the same results as canned pineapple.

Friday, January 6, 2012

Hiking Waterfall Trail at the White Tank Mountains

Waterfall Trail White Tank Mountains.

The appeal of a waterfall at the end of the trail probably makes the White Tank Mountains Waterfall Trail one of the most popular trails in the county (link to White Tank Mountains Park).  While the end goal might be reaching a waterfall, the scenery along the way can make the trip quite enjoyable.  Added to that, remnants of an ancient culture, easy accessibility, and a relatively short round trip, all make a good quality hiking experience for just about anyone. This year one of my new year resolutions is to hike 150 miles and to blog about it here.  I hopefully will be giving you a short nature guide tour on-line.  I want to visit each of the parks within the Maricopa County Parks system.  Which maybe will be just interesting and maybe will be helpful to you if you hike the Sonoran Desert.  Also, it might just inspire you to go hiking and do a little nature walk of your own.  This hike ticks off two of the 150 miles.
The hill or mountain side on the White Tank Mountains Waterfall Trail is rocky and drier than the adjacent bajada.  It therefore has more of an abundance of palo verde, brittlebrush and barrel cactus.
Beginning at the parking lot, the trail is very flat and universally accessible.  The first half mile or so hikes along a granite mountain or hillside to the left, and a relatively flat bajada, or alluvial fan, to the right.  Looking closely, there are some obvious differences between the mountain side and bajada.  The mountain side being obviously more rocky has a greater abundance of palo verde trees, barrel cacti, and brittle bush.  These plants are more highly adapted to rocky and droughty conditions of the hillside than to the deeper soils that absorb more water below.  On the bajada side there are far fewer rocks and much deeper soils.  Deeply rooted Ironwood trees and creosote brush take hold in this deeper soil.  There is also an abundance of triangle-leaf bursage, an indicator of a well developed soil, typically with caliche, a hard calcium deposit a few feet under the surface. 
The upper portion of a bajada along the White Tank Mountains Waterfall Trail.  Here the deeper bajada soils support more deeply rooted plants such as ironwood and some creosote bush.  Triangle-leaf bursage is also abundant and indicates a well developed soil, likely with caliche.  
At the end of the flat paved portion you will finally reach Petroglyph Plaza, an ancient art and story gallery of the Hohokam Indians.  These petroglyphs were carved into the black veneer that covers most of these large blocks of granite.  The black veneer is technically called “desert varnish” and is quite common on desert rocks that have been exposed to the atmosphere for long periods of time.  Bacteria form the varnish by carrying out a chemical reaction with dust that falls on the rock, forming the black covering.  The thicker and blacker the varnish, the longer the rock has been sitting in one location.  Most of the petroglyphs were made around 1000 years ago and too be honest we really don’t know what most of them mean.  Their meanings were lost with the Hohokam culture when they abandoned the Whitetanks about 700 years ago.
Petroglyphs found in the Waterfall Trail canyon.
Hiking past Petroglyph plaza the trail becomes a little rougher but still not bad.  Here, you start to walk along the wash that is fed by the waterfall during heavy rain.  The area around the trail becomes extremely rocky and rough.  All of the plants present earlier on the trail are still common but sort of mixed together.  In addition, jojoba is found in abundance, which seems to prefer cooler rockier areas with slightly more water, which is exactly the case in this canyon.  If you look in the wash there is also the presence of mesquite and cat-claw acacia, both of which take advantage of flows of water in the wash that happen maybe a few times each year.  Ironwood trees are oddly in abundance in this area, and are likely a result of their deep roots taking advantage of water from the wash infiltrating deep into the soil. 
This is typically what the "waterfall" looks like.  The pool at the base of the falls is all that is left after a month or so without rain.
Finally, after a mile of hiking the end of the trail and the head of the canyon is reached.  Unfortunately, searching for the waterfall at the end of this trail is little better than searching for a pot of gold at the end of a rainbow.  At least with this trail the narrow rock walled box shaped canyon is quite a spectacular site, but the waterfall is rarely flowing.  The falls run only after sufficient rainfall, say an inch or more, and typically run no more than few days after that.  But when the water is flowing it is quite a spectacular site with water gushing and shooting narrowly over the cliff far above.  Once the water enters the wash bed though it quickly sinks into the deep sediments but continues to flow downslope.  While plants and animals on the surface can’t really take advantage of this water lost into the sediments, deep rooted plants such as the mesquites and ironwoods easily absorb the water months after all traces of water on the surface have disappeared.  The waterfall and its wash therefore explain the abundance of these plants further down the canyon and along the bajada.  
The wash below the waterfall.

Monday, January 2, 2012

What Your Body Does to Alcohol: Alcohol Dehydrogenase

The enzyme alcohol dehydrogenase (ADH) is found only in the liver and converts alcohol (ethanol) into acetaldehyde, then acetaldehyde dehydrogenase (ALDH) converts acetaldehyde into acetic acid (commonly known as vinegar) which is harmless to the body.  
Some of you may have had a few drinks on new years eve...  And some may be wondering what happens to alcohol once it enters your body.  And how does your body get rid of that alcohol once it enters your system?  To be sure, alcohol is a toxin which amazingly most peoples bodies are relatively adapted to.  Though still, your body must get rid of the alcohol within your body, otherwise it might kill you.

With any alcoholic drink, the alcohol is rapidly absorbs into the blood stream through the stomach and small intestine.  Once in the blood, alcohol rapidly travels through out the body.  The most notable and immediate effects on the body take place in the central nervous system, the brain and spinal cord.  These organs are depressed, or slowed down, by alcohol and cause the rest of the body to also slow down.  This results in confusion and lack of coordination.  If these and other organs are exposed to too much alcohol for too long the alcohol will kill the cells.  The cells of the liver are the only cells in the body with any defense against alcohol poisoning.  Liver cells produce the enzyme alcohol dehydrogenase which converts alcohol into acetaldehyde.  Acetaldehyde is then converted into acetic acid, more commonly known as vinegar, which is harmless to the body.  The body then can excrete the acetic acid out through urine.  The liver process about one half ounce of alcohol per hour, and drinking more alcohol faster then your liver can process it will result in inebriation, alcohol poisoning, and in large amounts even death.  The liver thus processes alcohol out of the blood for the entire body.  Again, alcohol is a poison to which your body is adapted to in small amounts, large amounts will kill you simply because the liver can't keep up.  Without the activity of alcohol dehydrogenase in your liver though, even small amounts of alcohol could kill a person.

Some people have livers that produce more alcohol dehydrogenase when compared to others.  People that produce more alcohol dehydrogenase in their livers are able to process more alcohol and therefore not get drunk as easily.  Some people produce extremely low levels of alcohol dehydrogenase and therefore are extremely susceptible to drunkenness and alcoholism.  Some ethic groups genetically do not produce much alcohol dehydrogenase and are therefore very prone to alcoholism.  Interestingly, several types of mushrooms from the genus Coprinopsis contain a chemical called coprine, which inhibits the livers ability to process alcohol.  Inky cap mushrooms are the most common species consumed within this genus.  Coprine inhibits acetaldehyde dehydrogenase and without this enzyme functioning, acetaldehyde can accumulate to toxic levels.

So hopefully you didn't test your livers ability to produce alcohol dehydrogenase too much this new years. And hopefully you are one to setting some good new years resolutions.  In my next post I will be discussing one of my resolutions.  And happy new years to you!