Apr 15 2010
Alright, I am having trouble really understanding what the book means by “nuclear fuel cycle”. All I can really find on it is the diagram and I’m having a hard time really knowing what I should be taking out of it. Is the nuclear fuel cycle comprable to the nitrogen cycle in that it’s natural? Or is it a step by step process? If so, what are the steps?
I know it’s late but if someone could help that would be great!
Mar 01 2010
In class, we uncovered 3 different issues causing ocean pollution. I want to focus on one, runoff of nutrients. It occurs only in lakes, streams, or coastal areas (the nutrients have to run off from the land), and only includes nitrogen and phosphorus.
This nutrient runoff from fertilizers and feedlot manure is also called “cultural eutrophication“– when bodies of water receive excess nutrients that then cause excess plant growth (algal bloom).
Cultural eutrophication starts out as just excess nitrogen and phosphorus entering the shores. Plants then take up the fertilizers (natural or not) and surpass normal, sustainable growth for the body of water. These algal blooms start to close off the surface and cause a decrease in the amount of light that hits the floor. A decrease in sunlight then causes a decrease in photosynthesis which usually supplies the water with dissolved oxygen. Because photosynthesis decreases, so does the amount of dissolved oxygen (D.O.) in the water.
We have seen this “overpopulation” effect in our population dynamics unit. The algae exceed the K, or carrying capacity, then comes a massive die off of the species. After the algae dies off, it leads the way for decomposers to infiltrate the body of water. The decomposers increase exponentially, again causing the D.O. to decrease even more due to respiration by the decomposers. If it hasn’t happened already at this point, many fish die because they cannot get the oxygen they need to survive.
The runoff of nutrients can even lead to red tides and oxygen depleted zones, or “hypoxia,” like the sever case that is growing and growing in the Gulf of Mexico.
Here is an animated version of what we learned in class:
I found an interesting article about a bay that I live by during the summer. There has been a lot of press about this issue of fertilizer runoffs from yards surrounding the bay. These things happen more often than you think and can really cause some severe damage to not only the ecosystem around us, but to businesses and restaurants revolving around the fish/shellfish industry. Enjoy! http://www.pressofatlanticcity.com/news/press/ocean/article_905b2f50-1e9f-11df-867e-001cc4c002e0.html
HABs — Harmful algal blooms
http://serc.carleton.edu/images/microbelife/topics/red_tide_genera.v3_300.jpg
Sure this picture looks cool with the reds and blues BUT this is an example of a harmful algal bloom. These HABs can be very detrimental to a community. They produce toxins that not only effect the fish, shellfish, and marine animals, but also the marine birds and people as well. Over the years the HABs have caused more concern and prevention methods are now being looked into.
That is all we covered in class today, the other 2 ocean pollution issues are coming up this week!
Dec 17 2009
Alright, quick question. Are keystone species and foundation species always linked? In my notes I have that Giant Kelp is a foundation species because it gives shelter to creatures and feeds otters who reduce the sea urchin population. The Otter is known as a keystone species. Is this coincidence or is every foundation species somehow linked to a keystone species?
Dec 07 2009
I understand urbanization, the movement of people from rural to urban areas, and urban sprawl, when these people shift outwards to the suburbs as the city expands, my question is about the consequences of urban sprawl. Just to clarify for myself, this is actually worse than people staying in the center city because it not only “eats up” the land and resources around the city but also more energy is wasted because the same amount of energy is now used to support less people?
Also, I know in the northeast there is huge urban sprawl around NYC, but I feel like the city isn’t struggling economically like it should be according to our reading. There are towns very close to NYC that have people commuting into the city for jobs, but the book says people spreading out should cause a decline in the downtown business area. I don’t understand if this is just an exception to that general pattern or if I’m missing the point on the pattern as a whole. Anyone have an idea?
Nov 04 2009
One of Mr. W’s favorite brain rules is #5, repeat to remember, so lets revisit what we learned yesterday about niches.
Every organism has a niche, but how are they determined?
When an organism’s environment changes, it has 3 choices. It can adapt, migrate, or die. Part of what we talked about today was organisms adapting to their environments to ensure survival.
The two types of niches we talked about today were fundamental and realized. A fundamental niche is very general; realized is specific within the fundamental niche. Think about it like report card comments. A teacher may say, “this student is doing well, but they have not reached their maximum potential.” The full potential of the student is similar to a fundamental niche, they have all this room to grow but have only realized a portion of it.
http://birdwatch.ph/images/gallery/lsplover1.jpg
This picture of the Sand-Plover shows both fundamental and realized niche. The fundamental niche extends past the boundaries of the picture, but the realized niche is that strip of land that the Sand-Plover is able to eat from. This bird has a long enough beak and legs to enter the water along the shore line and eat safely. This area is probably the farthest out it can reach for food. The flamingo, on the other hand, has much larger legs and can reach farther into the water; therefore, the flamingo travels into deeper water to catch its food. These different water levels are the realized niches of the different bird species. The fundamental niche is the whole area that is the coastline, where both birds can successfully eat from. Where the different birds eat is an example of resource partitioning. Species can occupy the same area (fundamental), but they become more specialized by adapting. If the birds didn’t adapt, they would be left with only 2 other options: migrate or die.
To review some niche descriptions:
