PDS AP Environmental Science 5th Period 2010-11

How is nitrogen dioxide both a primary and a secondary pollutant?

I have in my study guide the phrase carbon neutral as part of the benefits of biomass energy, and I was hoping someone could remind me of what that is because I don’t have a description to go along with it, and I don’t remember what the phrase means.

So I know what terracing and contour farming are, but I feel like besides the fact that terracing is more like steps they are basically the same. Is there any difference really between the two because they both seem to be the same idea of forming strips that are perpendicular to the slope on a hill or mountain to help avoid erosion, so why choose one over the other?

To start off, we discussed various causes of degraded soil such as:

• Erosion
• Desertification
• Salinization
• Waterlogging
• Decreased Fertility

When it comes to humans, overgrazing, deforestation, and cropland agriculture are the greatest threat we pose to soil quality.

Farming requires the removal of the O Horizon so that the topsoil layer is exposed, but the loss of topsoil is what farmers are most concerned about. It takes centuries to replenish just 1 in. of topsoil, so losing it can be very costly. To make topsoil, weathering occurs to build up the inorganic parts, and decomposition occurs to build up the organic part of the soil.

Soil, like trees, is a renewable source and when you lose organic matter in the soil, its fertility goes down. (In general, the darker the soil, the more fertile)

We also talked about soil erosion and how water is the number one erosion force. The known types of soil erosion due to water that we talked about (but don’t need to know in great detail) are:

• Splash
• Sheet
• Rill
• Gully

Towards the end of class, we focused on how we can reduce soil degradation. One way was by using proven agricultural techniques like planting crops without disturbing the soil, which is called low or no-till farming. Keeping the soil covered with vegetation too can help soil fertility. Other types of farming techniques include terracing (which works best on steep mountains), contour farming (which works best on hilly terrain), strip cropping/intercropping, alley cropping, or farming using windbreaks or shelterbelts. Below are images of some of these techniques so you can get a better idea of what some of them talk about.

Terracing

Contour Farming

Windbreaks

We watched this informative video in class to better understand soil conservation:

Soil Conservation–YouTube

After the Dust Bowl, the government began to get involved in soil protection, and these acts were passed:

• Soil Conservation Act and Soil Conservation Service (1935-Now the NRCS)–this act created soil conservation programs
• Food Security Act (1985)– this act established subsidies paid to farmers for taking erodible land out of production to plant trees or grasses. (Basically the farmers would be paid to not farm)

So I understand what deep well injection is, but I’m not sure what the negative is. For example, with the surface impoundments the negative effects are that they can flood and therefore spread hazardous waste. I know we talked about how the earth doesn’t stay still so there could be movement that could lead to leaks, but I thought that was for the underground storage thing we talked about in class today. I feel like there was a whole separate problem with deep well injection that I just can’t remember…

I was wondering if someone could explain to me the Triple Bottom Line idea because I have it in my notes with this Venn Diagram, but I don’t really know what it is talking about or what it represents.

Today we talked about the phosphorus cycle. Phosphorus, we learned, is very important because it is a main component in things such as phospholipids, DNA, RNA, ATP, and ADP. By looking at the diagram in our book and study guide, we noticed the main reservoir for phosphorus is sedimentary rock, which is part of the lithosphere. Following sedimentary rock are soils (which have a living and nonliving component and are part of the lithosphere), oceans (found mostly at the bottom), and mineable rock, which is part of the lithosphere. One noticeable difference from the carbon cycle is the fact that there is no atmospheric phase, which means the cycling of phosphorus is much slower than in the carbon cycle, and this is a cause of phosphorus being a limiting factor for producers.

Phosphorus Cycle

Image Source:

http://arnica.csustan.edu/carosella/biol4050w03/figures/phosphorus_cycle.htm

A problem with the phosphorus in the ocean is that after it washes into the ocean, it goes right into the sedimentary rock. This is a problem because producers need phosphorus to grow, so phosphorus becomes a limiting factor in the oceans. Humans have a major impact on the phosphorus cycle because they create situations where there is excess phosphorus in the water. One thing that humans do is they mine so that it is possible to make inorganic fertilizers and detergents. By doing this, though, they are adding excess phosphorus to the land and water which causes problems such as the one described below:

As fertilizer (which contains nitrogen and phosphorus) increases, it runs off into the water, which causes increases in N and P in the water. This leads to an algal bloom (increase in algae) which eventually leads to a crash because of the lack of nutrients since all the nutrients are being used up. When this happens, decomposers move in and break down the dead matter, which decreases the amount of distilled oxygen in the water, which the fish and other aquatic organisms need to survive there. Since there isn’t enough oxygen, the fish either leave or there is a fish kill because the fish could not leave fast enough. This in turn produces a hypoxic situation like the one we talked about in the Gulf of Mexico. This whole process is called eutrophication.

Eutrophication Process

Image Source:

http://motherjones.com/environment/2006/03/eutrophication-process

Another impact that humans have is that they concentrate waste lagoons. Basically, there is an increase in the number of animal feedlots (grazing areas where animals are kept and fed). This produces large amounts of waste (which contain high levels of N and P) from the animals, and, when it rains for example, there is a lot of runoff that carries this nutrients into the water and recreates the same problem that is listed above. In short, excess amounts of phosphorous in any situation causes a problem.

Outside of the phosphorus cycle, we also touched on the issue that people see with changes in carbon dioxide levels. When people say they are concerned about climate change, they are referring to this positive feedback loop:

CO2 increases–>Temp increases–>Permafrost in tundra melts because of increase in temperature–>Increase in amount of decomposers and therefore decomposition–>Increased amounts of CO2

So I know the difference between the two successions but I was wondering if with primary that not only could there not be any organisms, but there also couldn’t be any soil.  Also, I know that we talked about an old parking lot as primary succession and how there wasn’t any soil (which is what made me think about my first question) and I did not write down how the soil or plants were able to start up in the parking lot. Can anyone help me out??

I think one of the biggest problems that we face today is pollution. I think because we have had a hard time with moderation and lots of companies are trying to grow and industrialize, it will be hard to convince people to cut back on things that cause pollution.