PDS APES 5th Period 2009-10

I was digging through old files and found this biogeochemical cycle story by Michael G. Thought it covered things pretty well, and might be a good review:

A Sulfur Atom’s Tale
One could almost hear a sigh of boredom echoing through the subatomic landscape, the resigned wheeze of a sulfur atom on quarantine. When he first joined up with his four oxygen buddies, he thought being called “sulfate” would be a blast; however, after eons and eons of being shuffled around, pressed, pushed, prodded, heated, and pushed around some more, he had been pressed into the very middle of a patch of sedimentary rock. There was an expectation of numbness, an infinite determination not to resist; however, this sulfur atom just had to escape.
And then the rains came. The carbonic acid-laden water trickled down through the hairline fractures of the rock, quietly carving a path of runoff—of freedom—that the sulfur atom simply couldn’t pass up. Grabbing his four oxygens by the electrons, he dove in headfirst and rode the incalculably hectic waves of water molecules, grabbing on for dear life as he swirled with the whim of the trickling raindrop. A seemingly infinite number of water molecules soon surrounded the sulfate, curiously sniffing his negative charge and then backing away, a hectic herd that could not decide whether or not to stay next to the sulfate. Hmph! Who needs them; I’ll show you just what I can be, the sulfur atom—safely within his sulfate molecule—mused to himself, as his raindrop approached—
What was that? All those hairs? A living wedge in the rock? It couldn’t be, and yet it was. The grass root had snaked its way through the sedimentary rock, seeking out water and dissolved nutrients. The sulfur atom clenched its bond and held on, as the raindrop flew into the root as if entering an atomic Charybdis. Up the root; into the leaves; into the mouth of the rabbit; into the back left leg of the rabbit; into the fox’s mouth; into the fox’s paw: it flew by the sulfur atom as less than a blink. As soon as it had started, however, the sulfur atom could almost make out the looks of rock again: the fox had died, and decomposers and detritovores were returning the sulfur to the lithosphere. Oh, no; you can’t make me go back! he huffed and puffed, pulling his oxygen companions by his polar covalent bonds and plunging into another raindrop. This one had a chance to go somewhere, to be a part of something bigger than itself; indeed, the raindrop became a creek, and that creek became a river, eventually leading to something so large, so teeming with infinite infinities of water molecules, that the sulfur atom could not help but gasp.
The ocean: the sulfur atom’s new home. Still wearing his sulfate costume, he looked about amid the literal seas of water molecules, trying to find other sulfate molecules. He saw them, but he could do nothing but pity them: they were drifting down, down, down, down to the very bottom of the ocean floor to form sediment. He couldn’t help but chuckle to himself; their existences would be like his just was, an eternity of waiting, an instantaneous spurt of life in the marine food web, and then another eternity of waiting. As he drifted about, he soon found himself passing by some phospholipids. Hm; I haven’t seen those since—
Oh, no. I’m in a bacterium. And right he was; indeed, the bacterium saw right through the sulfur atom’s sulfate costume, heartlessly shearing off those four oxygen molecules with which the sulfur atom had spent billions of years. It was almost a sad moment for the sulfur atom, which had now to clumsily wave about its new appendages, two methyl groups. He felt like an Edward Scissorhands with clubs for arms—decidedly clumsy. And yet those clubs—those Mickey Mouse-like hands—were actually far from clumsy. He was rising! Up, up, and out of the water he rose, until he began to see some N2 and some O2. He realized that he must finally be in the air, and his new identity suddenly made sense: he was dimethyl sulfide, and he was king of the atmosphere—at least, he felt like it.
He did, at least, until he started to feel the worst sunburn he could’ve possibly felt, one that ripped his floating club-hands from his very covalent bonds. All of a sudden, he was flitting about, colliding with all sorts of other particles without a sense of being or sense of what in the world was happening. Then, as soon as it began, it ended, and the sulfur atom now found himself with four new oxygens. He was sulfate again. This time, however, he noticed some tagalongs, a ragtag duo of hydrogen atoms that pestered and followed him wherever he went. They were like the little brothers he never had—or wanted, for that matter—so the sulfur atom was quite confused about this addition. In his new form—H2SO4, or sulfuric acid—he suavely hitched a ride on a passing water molecule, gaining access to a raindrop on an express route downward. Gravity yanked him towards the earth’s surface with an exhilarating acceleration, though the moment was over before it could register on the sulfur atom’s sense of time.
As the little dots of green on the ground suddenly became increasingly clearer as he descended, he could just make out the very patch of grass he had once been a part of. The raindrop collided; his sulfuric acid burned the grass; and ricocheting off the now-injured leaf, the sulfur atom found himself in the same patch of soil he had been in a very short time ago. Water coursed by him on a determined course downward, and he followed, eventually entering the—
Wait a minute. I’ve been here before. And indeed he had: it was the very same sedimentary rock he had been a part of for as long as he could remember. His adventure a blip on the cosmic expanses of his time of existence, he pulled in his four oxygen atoms, wiggled himself into a space in the rock, and went to sleep.

This is a blog post I’m making as both a personal study tool and a potentially beneficial class review. Enjoy!

Urbanization is the demographic shift from rural areas to cities and their outlying urban areas. There are five major global trends regarding this phenomenon that you need to know:

1. More people live in urban areas than ever before, and that percentage is rising. From 1850 to 2007, the percent of people living in urban areas skyrocketed from 2% to 50%, and we’re tracking to hit 60% by 2030. Most of this growth is in developing countries’ already stressed cities.
2. The number and sizes of urban areas are mushrooming. Each week, 1 million more people join urban areas’ populations. Between 2006 and 2015–a scant six years away–the number of urban areas with at least 1 million people will jump from 400 to 564.
3. The urban populations of developing countries are rapidly increasing. By 2030, the percent of people living in developing countries’ urban areas will jump to 56% (from 2007′s 43%), and in South America, 80% of the people already live in urban areas.
4. Developed countries’ urban growth is slower than developing countries’ urban growth. Despite this, projections indicate that 84% of developed countries’ populations will live in urban areas by 2030. (compared with 2007′s 75%)
5. Poverty is increasingly urbanized. At least one billion people worldwide live in crowded, unsanitary slums and shantytowns or live in cities’ outskirts. This number may double in 30 years.

Why is poverty becoming urbanized? Well, that’s inextricably tied to the very reasons why people end up in urban areas in the first place. There are factors that pull (attract) people to urban areas, and there are factors that push (force) people to leave rural areas for urban areas.

• Pull factors: jobs, food, housing, entertainment, freedom from religious, racial, and political conflicts
• Push factors: poverty, lack of land for growing food, declining agricultural jobs, famine, war

As more and more people join urban areas, they have to grow, and in some cases, this growth qualifies for urban sprawl, the growth of low-density developments on the edges of cities and towns. These developments result in loosely connected “hodgepodges” of housing developments, office complexes, and commercial centers. Granted, there are some requisites for urban sprawl to occur: affluence, ample and affordable land, automobiles, cheap gasoline, and poor urban planning. Charlotte seems to be suffering from this sort of spreading-out.

Because everything in urban sprawl is spread out over large swaths of land, there tend to be many problems associated with urban sprawl. I will break them down by category:

• Land and biodiversity: As urban sprawl “gobbles up the countryside,” as our book puts it, it results in the loss of cropland, the loss of forests and grasslands, the loss of wetlands, and the loss and fragmentation of wildlife habitats.
• Water: With more people comes an increased need for water, and this translates into an increased use of surface water and groundwater. Due to clear-cutting wide swaths of vegetation–and the subsequent loss of root systems–there is increased runoff and flooding. All of those people produce all sorts of pollutants, which lead to increased surface water and groundwater pollution, the most undesirable one being sewage; moreover, the growing numbers of people decrease natural sewage treatment.
• Energy, Air, and Climate: Urban sprawl tends to result in nonexistent or inadequate mass transportation systems, and people are consequently wedded to their automobiles, leading to increased air pollution, increased greenhouse gas emissions, and enhanced global warming. The increased demand for energy skyrockets energy production–leading to the aforementioned effects–and energy waste also rises due to low population density.
• Economy: As people leave the city to the suburbs–the classic urban sprawl scenario–much of the city’s tax base leaves with them, leading to higher taxes, increased unemployment in the central city, and the decline of downtown business districts.

Please keep in mind, however, that urban sprawl is the excessive end of the spectrum of urbanization; as a whole, urbanization much more of a mixed bag, with both pros and cons.

Pros: centers of economic innovation; educational and technological leaders; better access to medical care and family planning; recycling is more economically feasible; helps preserve biodiversity by concentrating people in cities and reducing stresses on wildlife habitats

Cons: unsustainable ecological footprints (urban areas are 2% of land area but consume 75% of its resources); lack of vegetation (shade, oxygen, absorb air pollutants, cooler temps.); huge use of water; produce most pollution (and is concentrated); increased spread of infectious disease, especially if adequate drinking water and sewage systems are not available; “heat island” effect; light pollution

Cities are constantly trying to tackle these problems, and one of the most pressing is the one of transportation and its effects on the city’s well-being. In many ways, city growth somewhat hinges on transportation: in compact cities (build “up”) like Tokyo, people build up and walk, ride bicycles, or use mass transit; in places like the United States, however, the spread-out, built-for-the-car dispersed city (build “out”) is the more prevalent type. There seems to be a pattern with transportation, though; as efficiency increases, the need for scheduling also increases, and this scheduling is something into which people must buy. Bicycles do not necessarily fit this mold–indeed, they may be one of the most efficient means of personal transportation–but their size, small range, and lack of weather protection makes them suited only for some conditions.

There is a way our book mentions, however, in which we can create and maintain sustainable cities: smart growth. Smart growth calls for more environmentally sustainable development by lessening dependence on cars, controlling and directing sprawl, and reducing wasteful resource use. This can be accomplished by limits/regulations, protection, zoning, taxes, planning, tax breaks, and revitalization for new growth.

An ecocity is essentially a more environmentally sustainable city than the one smart growth attempts to address, for it emphasizes these six sustainability goals:

• Build/re-design cities for people, not cars
• Use solar and other locally available renewable energy resources; design buildings to be heated and cooled as much as possible by nature
• Use energy and matter resources efficiently
• Prevent pollution and reduce waste
• Recycle, reuse, and compost at least 60% of all municipal solid waste
• Protect and encourage biodiversity by preserving surrounding land and protecting/restoring natural systems and wetlands

Pictures:

• Lima: http://www.responsibletravel.com/community/images/member/f_51602718_3196.jpg
• LA: http://www.photodiary.org/large/e_1167.jpg
• Curitiba: http://www.freewebs.com/filipebruno/curitiba.jpg

On Thursday, we explored the biogeochemical cycles of phosphorus and sulfur, two fairly important elements for life. During the second half of class, we did an activity with balloons that attempted to visually illustrate the transfer of carbon among the different “spheres” (geosphere, biosphere, atmosphere, hydrosphere). Without further adue, the phosphorus cycle:

Phosphorus (element symbol P) is more commonly seen in the natural world as good ol’ phosphate, a polyatomic ion (PO4 3-) that is crucial for nucleic acids’ phosphate backbones, ATP and ADP, and phospholipids, those comet-shaped molecules that form the phospholipid bilayer that makes up cell membranes. Hm: DNA, ATP, and cell membranes. Kind of important.

Reservoirs: 1. Sedimentary rock     2. Ocean sediments     3. Soil matter

Key Equations: none, though you should know the formula for phosphate (PO4 3-)

Anthropogenic Impacts: Runoff from mining, sewage, and excess fertilizers runs downstream and helps contribute to algae blooms (“red tides”), which lead to drops in aqueous DO concentrations, a less-than-ideal consequence for fish in that body of water (“fish kills”).

The Quick Rundown: Weathering releases phosphate from rocks, which then dissolves in water. This water does one of two things: it gets absorbed by plants, thus cycling the phosphorus through the terrestrial food web; or it runs off into the ocean, where it either enters sediment or the ocean food web. Marine birds eat fish  that contain this “ocean phosphorus” and then excrete it on land. The buildup of phosphate-rich bird dung develops into rock over time, thus completing the cycle. There isn’t an atmospheric component to this cycle.

Side note: phosphate mines literally mine old animal dung piles for phosphate, though I believe they prefer to call it “guano.”

Sulfur (chemical symbol S) is a crucial component in two of the twenty amino acids. If you really want to know, the amino acids are cysteine and methionine: Cysteine creates disulfide bridges that help hold together proteins’ tertiary structures, while methionine is basically the “Start button” of protein translation (ribosome sandwiching mRNA). I’m sorry for the geek moment; I enjoyed that unit of AP Bio.

Reservoirs: 1. Rocks     2. Ocean sediments

Key Equations:

Acid rain: H20 + SO3 ——–> H2SO4 (sulfuric acid)

Fossil fuels burning (in this case, impure coal): FeS2 + O2 ——–> Fe2O3 + SO2

General Sulfur Oxide Formula: SOx (SO2, SO3)

Sulfite: SO3 2-

Sulfate: SO4 2-

Dimethyl sulfide (DMS): CH3SCH3

Anthropological Impacts: The burning of fossil fuels and smelting–the melting of ore to collect and purify a given metal–both release SO2 into the atmosphere via the burning of impure compounds that contain sulfur. For example, coal can have impurities of iron pyrite (FeS2), and when that coal is burned, iron pyrite and oxygen react to form iron (III) oxide and sulfur dioxide (SO2), a major air pollutant. SO2 reacts in the atmosphere to eventually form sulfuric acid (H2SO4), one of the major components of acid rain.

The Quick Rundown: Sulfates in rocks get freed via weathering and either enter ocean sediments or are absorbed by plants, whereupon the sulfur enters the terrestrial food web. Decay of organisms returns the sulfur to the soil and rocks, where it is recycled once more by plants. In the ocean, bacteria produce a byproduct gas called dimethyl sulfide (DMS) that serves as a particulate for cloud formation and can react to form atmospheric SO2. This SO2 then reacts to form H2SO4, which falls to the earth as acid rain.

The balloon activity we did in class helped to illustrate the proportions of carbon in the different “spheres” (biosphere, geosphere, hydrosphere, atmosphere). Before I continue in describing numbers of balloons, let’s get straight what one balloon equaled in this experiment:

1 balloon  = 821 petagrams (the amount of carbon in the atmosphere)

1 petagram = 1, 000, 000, 000 metric tons = 2.2 trillion lbs

For a frame of reference, the United States  has 250 million cars on the road today, and assuming an average car weight of 2000 kilograms, the total mass of all of the United States’ cars is only .625 petagrams. That’s not even .1 percent of the mass of one balloon, which is 821 petagrams.

Anyway, the breakdown:

Atmosphere: 1 white balloon

Land and Soil Biomass: 3 green balloons

Fossil Fuels: 5 black balloons

Ocean Water: 46 blue balloons (represented with four bigger balloons and six normal ones, with the assumption made that one bigger balloon equaled ten normal balloons)

Lithosphere: 100,000 brown balloons (Mr. Willard just gave the bag of brown balloons)

Note: Gasoline contributes CO2 to the atmosphere at a 1:3 ratio. Explained another way, if one burns a kilogram of gasoline, that gasoline releases 3 kilograms of CO2.

I was just thinking back to the two-part video we watched in class, and based on the readings and video–not to mention the book–it’s pretty clear to me that the 1980s were a period of, well, anti-environmentalism. I know that many environmentalists were overrun by pro-business, planetary-management members of the so-called sagebrush rebellion. What I wonder is this:

How exactly did the environmental movement lose its mojo in the late 1970s? After all, there was no shortage of natural disasters, and there was a ton of political momentum (Nixon and the EPA, Carter and the Superfund). Was it just a victim of the larger fear of a too-big government? Or did people specifically consider its message to be “extreme”?

This may not be an exact question about a concept, but studying just got me thinking.