Archive for 'EvanR'
Nuclear Power is often talked about as the new “clean” energy to replace some of our dependencies on fossil fuels. But people are also afraid of nuclear power. The word nuclear carries associations with bombs, disasters, cancer, and danger. Neither of those previous statements are fully accurate, and it is important to understand why.
First off, nuclear power, though far cleaner than most fossil fuel alternatives, is not fully clean. It does produce waste, in the form of depleted radioactive substances and irradiated materials. This is a problem which has to be addressed if we are to continue working on nuclear energy plants. Obtaining the nuclear material used is also a hazard. It too must be mined out of the earth with some of the same environmental destruction as mining coal. Although it is cleaner than coal plants, it is certainly not spot-free.
How does it work?
Our nuclear power plants run off of what is called a fission reaction, that is the splitting of an atom to produce vast quantities of energy. It is important not to confuse fission with its opposite, fusion. A fusion reaction (fusing two atoms together) is speculated to be more powerful and therefore cleaner. Unfortunately though our research tells us it is a better method of obtaining energy, we have not been able to master the process yet. So for now fission is all we get, but it definitely gets the job done.
Just how dangerous is this strange new science to utilize? Chernobyl, Three Mile Island, and now the Japanese nuclear crisis, don’t these disasters mean its too dangerous to use? False. The fact is these disasters are few and far between. They are also portrayed as worse than they actually are by the media. In Japan right now, most of the nuclear material released by the power plant has a half-life of about 8 days. That means half of it is gone in about a week, half that in one more, and so on and so forth. If you pick up a sunday paper or click the link below there is a wonderful article by Seth Borenstein which makes understanding our perception of nuclear power far easier than I could make it.
Some scientists have estimated that there is 315 billion pounds of plastic floating in the oceans. There is not an island of plastic, as some rumors say, but more of a soup of smaller particles of plastic and ocean.
Out of all the plastic in the ocean, only about 20% originated from ships at sea; the other 80% came from land. Some cities have seperate wastewater and stormwater systems where wastewater travels to a treatment facility and stormwater flows directly into natural bodies of water without any treatment. Other cities have a combined system of wastewater and stormwater, but when a heavy rain comes overflow of the system occurs which allows polluted water to flow into the ocean. No matter the water treatment system polluted stormwater finds its way back into the ocean carrying literally tons of plastics.
Without a doubt, plastic in the ocean causes a mryaid of evironmental issues, such as:
- Plastics are extremely durable, “every bit of plastic that has been made, except for the small amount that has been incinerated still exists today.” Plastics are so durable because they don’t biodegrade, but rather photodegrade. That is, plastic just breaks down into smaller and smaller peices. Bottom-feeders can mistake these small plastic pieces as zooplankton, and seabirds can mistake bottle caps as food. A video of drowing the ocean in plastic.
- Plastic serves as a cruise for organisms to sail the ocean currents causing biotic mixing–this is an invasive species vector. Organisms, like barnacles, live and grow on the floating plastic debris and drift on the ocean currents, spreading North American aquatic species to the coast of Japan as an example.
- Plastic can also act as little poison pills. Because plastic is hydrophobic and lipophilic (wont dissolve in water but will take up fats and grease), it can absorb oils and accumulate toxins, and some fish have been found to eat small plastic pieces which speeds up bioaccumulation in organisms.
How does carbon escape from sedimentary rock besides volcanic eruption? And the diagram in our books shows an arrow from “soil and soil biota” that connects with respiration, I am confused on what this means?
The nitrogen cycle, the most nitrogenous cycle in fact, is crucial to the biosphere because nitrogen is essential for such compounds amino acids, protein, DNA, and RNA. Most nitrogen is found in the atmosphere, but this nitrogen is inert, “broken”, because it is triple bonded to itself (N2). And because of atmospheric nitrogen’s inert nature there is relatively low levels in the lithosphere, hydrosphere, and biosphere; and is a limiting factor in plant growth.
The most abundant reservoirs of nitrogen are:
1. Atmosphere as N2(3,870,000,000), 2. Oceans as inorganic N (570,000), 3. Soil as ammonia, ammonium, nitrite, nitrate (115,000).
Here is a link to an animation of the nitrogen cycle: I am a link to an animation…fear me, I’m educational
Because most of the nitrogen is in a chemically inert phase in the atmosphere, lightning, human intervention, but mostly highly specialized bacteria are require to harvest the nitrogen. Bacteria are the only reason,excluding artificial fertilizers, why there is nitrogen in the soil and water–they are the nitrogen fixers, recyclers and drive the flux.
Some plants, called legume–clover, peas, beans, peanuts, etc., have a symbiotic relationship with nitrogen-fixing bacteria that are found in the plants roots. Other bacteria in the soil or ocean fix N2 and convert it to ammonia (NH3), which is toxic, or ammonium ion (NH4+), which is a usable form. Atmospheric nitrogen is converted to nitrogen oxides by lightening as well. Other nitrification bacteria convert ammonia and ammonium to nitrite ions (NO2-), another toxin, and then to nitrate ions (NO3-), another usable form. And there is even another type of bacteria that creates its energy by denitrification. As nitrogen is recycled, by decaying plant or animal matter, back to the soil some of the fixed nitrogen (NH3, NO3-, NO2-) is converted back to nitrogen gas and released into the atmosphere.
A visual representaion of the type of bacteria:
1. Because of the crops needed to sustain the human population, and crops like corn just suck the nitrogen out of the soil, a process was created to manufacture inorganic fertilizers abundant with nitrogen–the Haber-Bosch Process. With all this added nitrogen to the soils, there is a dramatic increase of nitrogen in the waters because of runoff form the soil. And with more nitrogen in the water eutrophication occurs (increase in N/P, increase algae bloom, population crash, increase decomposers, decrease dissolved oxygen “hypoxia”, decrease in fish, dead zone).
2. With the burning of fossil fuels, mostly crude oil as gasoline in cars, leads to smog and acid rain. Cars uses air (N2 and O2) in the high temperatures of the combustion engines in cars cause the reaction to produce nitric oxide (NO). Nitric oxide in the atmosphere combines with oxygen to produce nitrogen dioxide (NO2), smog. Nitrogen dioxide can react with water and produce nitric acid (HNO3), which is acid rain.
The biggest environmental detriment is the majority of the world’s massive dependency on nonrenewable fossil fuels. There is a finite amount of these fuels and even though as of now there is an abundance, eventually they will become depleted. To add insult to injury, when fossil fuels combust, they add carbon emissions to the air–with inefficient engines there is a significant amount produced. Drilling and mining for these fuels also cause environmental hazards: oil spills, deforestation, et cetera.