Modeling Aquatic Ecology - Bio 101 Lab 8

bugs-and-slugs-hidden-secret-healthy-seagrasses

In class yesterday we modeled aquatic ecosystems using aquaria with various conditions. We then monitored for dissolved carbon dioxide, dissolved oxygen and PH. Our control aquarium was just plain water, any dissolved gasses would enter the system via diffusion at the surface. In the other aquaria animal and/or plants may have affected the balance of dissolved gasses through the processes of photosynthesis and cellular respiration. We also had tanks with varied light, heat and aeration regimens in order to try to determine how these things affected the amount and type of gasses in solution and therefore the PH. Dissolved carbon dioxide would affect the PH as it reacted with water to create a weak carbonic acid, lowering the PH. Review your data. How do each of the other systems affect PH? In which systems is photosynthesis occurring? How should this process affect the balance of gasses? In which tanks is cellular respiration occurring? How should this affect the balance of gasses? Does your data support the ideas in theory? Why or why not? How do heat, light and aeration affect the balance of gasses? In your data does a higher CO2 concentration correlate to a lower pH?

cycles6.htm

Here is a simplified ecosystem showing the cycling of carbon. In the atmosphere carbon is mostly in the form of CO2. The plant uses this atmospheric CO2 for photosynthesis. Photosynthesis produces glucose and oxygen.

 Here is the chemical equation for photosynthesis 6CO2 + 6H2O --> C6H12O6 + 6O2

The animal uses the glucose and oxygen from photosynthesis to produce carbon dioxide and water.

Here is the equation for cellular respiration 6O2 + C6H12O6 --> 6CO2 + 6H2O

See how there is a relationship between the plant and the animal as the carbon cycles in the ecosystem? Ecology is about relationships. One of the ways these relationships can be described is by the cycling of the CHNOPS elements through the atmosphere, biosphere, hydrosphere and geosphere...the air, living things, the water and the soil and rocks. These cycles are known as biogeochemical cycles. When these cycles are in balance an ecosystem is healthy. Which of your model ecosystems had a balance of elements based on your testing? Which did not? what might happen to organisms in the ecosystems that were out of balance and why? Energy from the sun flows through food chains and ecosystems. A little energy is lost as heat at each link in the food chain. How did heat and light affect the balance of gasses in our model ecosystems?

2013-07-dead-zone-impacts-chesapeake-bay.html

The Chesapeake Bay is out of balance. Nutrient pollution from lawns and farms and pet waste causes algae to bloom. When this algae dies and overgrows it sinks and is decomposed by bacteria the consume a great deal of oxygen. These conditions are known as "eutrophic". Prolonged eutrophic conditions create what is known as a "dead zone" in the main stem of the Chesapeake Bay. This dead zone expands in the summer. Click the link to watch the video below and think about your models. How might we create a tank that models eutrophic conditions? What could we hope to learn from this?

Dead Zone Video

Brace for Impact! Lessons From Barringer Crater

Post under construction, come back later

Here I am, the dancing geoscience teacher in Barringer Crater

In this view of Meteor Crater you can see the overturned Coconino Sandstone

Here is the overturned Toroweap Formation

This shows both the Coconino and the Toroweap,
The older Coconino is on top
The impact created an inverted topography

 

Thermal Image of Barringer Crater
 The Coconino sandstone in red and the Kaubib Limestone in Green
North is at the top.
Image CreditMike Ramsey

Thin section of shocked quartz from the Coconino sandstone

From CheMin to TerraX - Evolution of an Idea - My Fortunate Encounter With David Blake

On the flight cross country to Arizona I was nearly breathless, partly due to America the Beautiful passing beneath me and partly due to the caliber of people I would be spending time exploring Mars analogs with in the coming week. As my journey unfolded I was not disappointed on either count.

One of the scientists I met was none other than David Blake from NASA Ames, designer of the CheMin instrument. This little technical marvel is busy sampling the mineralogy of the Martian surface aboard the Curiosity Rover as you read these words. Dressed in unassuming khakis and a simple button down, with a warm smile and a humble, inviting demeanor,  Dave might not fit the stereotype you have in your mind for an innovative genius, but he is. C'mon you didn't expect him to wear a "bunny suit" or a lab coat in a Marriott lounge did you? He is absent the ink stains and pocket protector some of you might have come to expect, but he has kudos aplenty for his work...much better  street cred, nerd style. Dr. Blake has his PhD in mineralogy from University of Michigan and has received both NASA's Exceptional Scientific Achievement medal (1998) and NASA's Outstanding Leadership medal (2013) 

His CheMin instrument uses X-ray diffraction to analyze pulverized mineral samples for organic signatures and has made the discovery of the first habitable environment on Mars.

 

Image Credit and technical specs

 Dave gave a basic description of how this works in a short lecture at the Mars Space Flight Facility at Arizona State University on day 1 of the symposium. X Ray diffraction or XRD quantifies minerals present and percent composition of elements by analyzing small amounts of pulverized sample material. This process is described by Bragg's Law which equates wavelength with the spacing of the crystal lattice which produces a characteristic angle at which the X-ray bounces off the sample. 

nλ=2d•sinθ

 This relationship was first fully described by Max Von Laue in 1914 and won him the Nobel Prize for Physics. 

Bragg's Law link and image credit

After learning how this tool makes accurate and quantifiable observations we had a wonderful talk by Don Boonstra on how to help students begin to make effective observations (more on that in a subsequent post)  Next we all loaded on the bus and made our own observations as we drove up highway 17 from the Basin and Range Province, through the transition zone to the Colorado Plateau. We learned geology all the while (see previous post) and stopped at the Old Indian Salt Mine to collect samples to put in Dave's Earth instrument, Terra X. The old Indian salt mine contains evaporate deposits and is a terrestrial Mars analog, it is pictured below, albeit a little askew...it was the hottest day of the year so far topping out at a sweltering 122F in the Verde Valley that day. I don't care what anyone says about dry heat, when temperatures are that much in excess of your body temperature even a short walk is taxing. I consumed almost 2 liters of water and a salt tablet during our short foray. 

 

Here are some gypsum crystals I collected. I was unable to find a perfect "desert rose". As I climbed up this huge mound of evaporites and sand I felt the "sand pile effect" described by chaos theory right beneath my feet. I knew if I ventured higher I was liable to slide back down incurring the nastiest of salt filled "road rashes". Might be myriad interesting equations to describe such a mishap but I didn't want to experience them. Anyway here are the crystals I did find, displayed on some Martian sand dunes for effect. Cue the disco music.

The first photo in this post shows Dave holding my pulverized sample in the "window" of the Earth evolution of his tool, the TerraX. This instrument, in its practical and easy to spot red field case, is rugged and magnificent. The field scientist in me had goose bumps when Dave invited me to hand over a sample for analysis. Even though I was pretty certain my sample was gypsum, it's not every day you get to zap a pulverized sample of a mineral you have collected with your own hands (on the hottest day on record) with an X-ray in a hotel bar. Adding to the mystique for me was the fact that the machine had also withstood extremes of cold in Antarctica, the continent of my dreams.  

 A percussion mortar is used to powder the sample. Dave rolled his eyes when I tried to hand over a large pinkish hand sample of what might be a granite concretion, so I handed over the gypsum instead. I should have asked for the rock hammer and gone outside to pound away. I can think of a special, stressful situation  I could have used rock pulverizing therapy to alleviate. (Not associated with anyone or anything on the trip mind you. ) Anyway I appear to be  traversing a wild tangent again, back to business.. The sample is loaded into the diffractometer' s sample window and slotted into the machine. A resonance sets the powder in motion and it is zapped with an X-ray. The machine then analyzes the sample using Bragg's Law and displays the results in a graph you can display on a computer, tablet or smartphone. Clever, clever. (Dave was a touch annoyed that we all taxed the machine with our smartphones at once but I think he understood and appreciated our starry eyed exuberance 

As CheMin identifies minerals associated with biosignatures on Mars, TerraX analyzes mineralogy for a variety of environmental, exploratory and research applications here on Earth. Terra X has also found its way into public health applications and is used to identify counterfeit malaria medication. From a spacecraft instrument designed for pure curiosity to an Earth instrument with many practical applications. I would say the money spent developing this technology is taxpayer revenue well spent. We must keep funding such research, it is fundamental to our growth and health as a human species, instrumental to the US role as a leader in science and technology and just pretty damned cool. 

At the close of the evening Dave gave me a copy of an informal paper he wrote about the development of this idea over 20+ years. It is a story of innovation, invention and reinvention, perseverance and belief. I think it is amazing. With Dave's permission I would like to cover it in parallel with the children's book every human should own and refer to "What  Do You Do With an Idea?" Check back soon. TTFN

Roadside Geology of Arizona Highway 17 Phoenix to Camp Verde

Sonaran Desert Rt 17 outside Pheonix

Here we are in the Basin and Range province, saguaro cacti growing in basin filling alluvial sediment. This is the Sonoran desert outside Phoenix, Arizona. This valley fill is thought to be several thousand feet deep. We pass Camelback Mountain and the Phoenix Mountains to cross the Salt River. This river is a major drainage of central Arizona and is a tributary of the Gila River which is in turn, a tributary of the Colorado River.

Arizona Drainage

Next we enter the transition zone, consisting of tilted mesas, capped by Tertiary basalt flows. This erosion resistant basalt creates "inverted topography" over geologic time. Lava flows into a valley, cools and hardens. Surrounding, softer rocks and sediments erode leaving the younger basalt cap characteristic of the mesas on highway 17.  Have a look at the diagrams below to visualize this sequence.

Sequence of events creating "inverted topography

Next on our journey, around the town of New River, road cuts expose fluvial conglomerates. In some places we can also notice angular unconformities developed on metamorphic slate and phyllite of Proterozoic origin.

Mile marker 15 characteristic rocks

Layers of rock in a road cut

Layers of rock in a road cut

Dark rocks in road cuts further along the way are iron rich cherts thought to be the metamorphosed portion of an ancient sea floor. Elevation here is 2000 ft. From here to the Colorado Plateau elevation increases steadily as we drive.

At Table Mesa Rd. Exit 236 layers of white lake sediments are visible in the road cuts. This part of the transition zone was laid down in a tertiary basin. In some beds here we also see poorly sorted volcanic clasts. Carbonate concretions are also evident. Outcrops of Proterozoic granite with associated contact metamorphics constitute the basement rocks here. 

 Rock layers in a road cut highway 17 approaching Cape Verde

 Rock layers in a road cut highway 17 approaching Cape Verde

 Rock layers in a road cut highway 17 approaching Cape Verde

 Rock layers in a road cut highway 17 approaching Cape Verde

   

The Aqua Fria River, another tributary of the Gila, flows through Black Canyon. So named because outcrops here expose basaltic and ash derived volcanics. Notice the red "baked zones" at the base of the flows in the final road cut photo above. As we move on, vesicular textures from gas rich magma become common. We are in the vicinity of the Crown King gold mine, closed in the 1950s after an estimated 2 million in gold was extracted from this hydrothermal deposit.

Metamorphic core complex

At the Sunset Point Rest Stop we are in the vicinity of the Black Canyon and Bradshaw Mountains, which lie to the West. These are part of a metamorphic core complex similar to the one in the diagram above. Here we see blocky, weathered metamorphic rocks punctuated by  sphereoidally weathered granites. The metamorphics lie above the granites.

 

Verde Valley, home to the old Indian salt mine evaporites, includes white, lacustrine deposits of Miocene age. The Verde Valley is shown in purple in the diagram below.

Old Indian Salt Mine

Arizona Tectonics

This environment is sooooo different from the one I just left. In this big state there are just three physiographic provinces. The Basin and Range, the central highlands and the Colorado plateau. The central highlands is a transition zone. 

 

 The Basin and Range exhibits north South faulting creating grabens (valleys) and horsts ( mountains) elevations in this province range from 4000 ft to >14000 feet. 

In the Mesozoic and Early Tertiary the geology of this area was shaped by compressional forces at convergent margins, specifically subduction zones. This led to a series of folded mountain belts to the east and later to the uplift of the Colorado Plateau. 

Subduction later caused an upwelling of magma along preexisting faults, creating volcanic structures and igneous plutons. The uplift also causes a thinning and elongation of the rock here. 

The main tectonic structure in modern North America is the western transform fault, the San Andreas Fault which will eventually separate California from the rest of the continent. 

Recent geologic history has been that of erosion in an arid environment. Ephemeral steams crate "washes" and alluvial fans which merge to create new structures. This cycle of erosion bears the fingerprint of flash flooding events. 

Crystal Grottoes Cave System

Down the west side of South Mountain and into the sleepy hamlet of Boonesboro we find Crystal Grottoes, Maryland's only commercial cave. It has been maintained and operated by the same family for 3 generations. 

 

The cave lies in the Great Valley which is an assemblage of easily weathered carbonate rocks including the cave rock, shown above, and known as the Tomstown Dolomite. 

The cave rock was dissolved by water with dissolved CO2 creating a weak and corrosive carbonic acid that over the years eroded the caves and carved gorgeous speleothems. 

 Here we see both stalactites (hanging from the ceiling) and stalagmites (protruding from the floor) they are kind of like stone icicles formed over millennia. Some have been growing so long that they have joined to form columns. 

 

. 

  

Here we see flowstones and draperies. 

 

This microcrystalline formation is calcite and is known as cave coral. The photo didn't do justice to the magical sparkle of this formation. 

 

In this view we are looking up toward the ceiling and we see many bands of color. The grey is calcite and calcium carbonate. The rusty color indicates an iron impurity and the green is algae. Algae spores enter the cave with visitors and the lights that display the formation provide enough energy for photosynthesis. The algae is periodically and painstakingly removed by hand from the cave formations. 

Spelunk!

Gambrill State Park

  

Standing at the overlook near the USGS marker you can see across the Middleton Valley to South Mountain at the other side of the Blue Ridge physiographic province. Here on high knob we stand on an erosion resistant quartzite monodnack with evidence of iron impurities. The air is clean and clear as attested to by the abundant lichen on the rocks. This crown of high knob is the Buzzard Knob member of the Weaverton Formation. This formation is phyllite capped by quartzite. 

 

We are standing on the east side of a large ,  recumbent anticlinorium.  The east dip is apparent.  The top part of this overturned anticline has been eroded away but can be inferred from the cross section shown below. The underlying sedimentary limestones here are Cambrian and the overlying metasandstone has its origin in Triassic sediments that flowed into this area during the breakup of Pangea. The rift is a failed rift and is the origin of volcanics characteristic of the blue ridge including metabasalt and phyllite. 

 

In this map of the Blue Ridge area we can see major formations and colluvium on the sides of the hills overlying the local bedrock. This accumulation of boulders, cobbles, pebbles and sand are of  quartzite composition and originates from mass wasting and stream action. This rubble makes identification of contacts and faults problematic in the field.