Wednesday, 4 June 2014

Strawberry DNA

Today's the last lesson of Science 7!

Next year you will study genetics.  To introduce the topic, we have a special guest speaker today.  Mr. Ralston will share a bit about his work in plant genetics and then we will extract DNA.

Tuesday, 3 June 2014

Santos vs Pinheiros

Research Question: How do the properties and characteristics of a certain body of water impact the ecosystems and the humans?

In Santos, 90% of the sewage is treated before being released into the environment. There are enormous water treatment stations in the city. In São Paulo, however, only 26% of the sewage is treated, the rest being dumped into the river Tiete and Pinheiros. This is one of the main causes as to why the rivers are so polluted. The rivers in Santos, on the other hand, is very clean, thanks to the city’s efforts in cleaning it up.
The city of Santos was one of the worst cities in the world concerning water treatment. It’s condition has drastically changed since the beginning of the project in 1920s when they first started to lessen the pollution and the stagnancy of the water.
Chemicals found in water:
Dissolved Oxygen: The low amount of dissolved oxygen in the river Pinheiros is due mostly to the algae. The algae absorb most of the dissolved oxygen in the river as soon as it goes into the water. The dissolved oxygen level is 2.4 ppm. That is next to nothing compared to the Santos river water, with a dissolved oxygen level of 6.1 ppm. That is roughly the amount that fawn and flora need to survive in the water.
Ammonium Nitrogen: There is a low level of Nitrogen Ammonium in both these bodies of water. Nitrogen Ammonium is an inorganic, dissolved form of Nitrogen and is bad for any living thing.  
Nitrogen Nitrate: Nitrate is another form of Nitrogen. It is Ammonium that has gone through the process of oxidation. It is one of the chemicals that is found in fertilizer. Nitrogen itself is an element that all living things need and have in their bodies. Nitrogen is mostly found in protein.  Concerning the diagram: The blue boxes represent stores of nitrogen, the green writing is for processes that occur to move the nitrogen from one place to another and the red writing are all the bacteria involved.
Phosphate: A phosphate (PO43−) as an inorganic chemical and a salt of phosphoric acid. It is mainly mined for fertilizer.
These are the test that have been recently completed in class. As you can see, there are drastic differences. This has a lot to do with the fact that Santos actually cleans most of it’s sewage water.
Dissolved Oxygen
2.4 ppm
6.1 ppm
0.2 ppm
0.1 ppm
Nitrogen Nitrate
0.2 ppm
0.6 ppm
60 ppm
1.0 ppm
140 ppm
1500 ppm
close to 0 ppt
6.0 ppt

The impact on the ecosystem is tremendous. The river Pinheiros is considered a virtually dead river. There  are not many creatures able to survive. With it’s low amount of dissolved oxygen, no plants or fish can survive. Algae is one of the only organisms that can truly flourish in the river. It is also the main cause of low dissolved oxygen. Because of this there is a lot of Ammonium Nitrogen in the water. Ammonium Nitrogen is an inorganic, dissolved form of Nitrogen which is found where dissolved oxygen is lacking. If we look at the test results though it is noticeable that the Ammonium Nitrogen level is very low. Yet we think this is an effect of the algae. Even though Ammonium is bad for animals and plants there is a process it can go through that turns it into Nitrate. This process is called oxidation. The algae absorb so much of the oxygen that not much, if any, of it can get into the water. Also, because of the Nitrate in the water the algae grows faster and the problem just keeps on escalating. With the excessive amount of sewage, trash, and the slow movement of the water, one rarely finds fish, mammals or reptiles nearby. Sometimes, a capybara is seen, or another similar creature.
The same happened to Santos in the 1920s. Because of recent dams, the water became stagnant. Santos was considered a deadly place, because of the diseases that could be caught there because of deadly insects, such as Malaria or Dengue. These such insects reproduce in stagnant waters, and because of the excessive amount of stagnant water (the whole part of the river that ran through Santos) there was an enormous quantity of breeding among those insects. With the dams destroyed, the currents came back, reducing greatly this issue. This is not a problem with the rio Pinheiros, since the water is so contaminated and polluted that even insects can’t, for the most part, reproduce in it.
In Santos the problem of water treatment has mostly been solved. 90% of the sewage is being treated. Also, to make sure the salinity (salt concentration) in the bay stays almost the same by pumping it through huge pipes out of the bay and into deeper waters. In order to improve this process, though, they can aim to treat 100% of the sewage, and reuse it. Also, there are better ways to treat water to drink. One example of this is using ozone. Yes, using ozone would be more expensive, but on the other hand, the taste of the water would be better, and this would show better advancement for Brazil.
In São Paulo, though, there is much that still has to be done in order to make the rivers acceptable. Firstly, the percentage of the sewage treatment has to rise drastically. In order to do so, more sewage treatment facilities can be built. Another possible way to help solve the problem is to place more trash cans around the city, and motivate the citizens to use them instead of throwing their trash on the ground. The trash will end up at the river eventually, and so polluting it even more.
In conclusion, the sewage treatment helped Santos greatly, and would have the same effect on São Paulo, if there were more treatment facilities. Santos was an example of humans not giving up on their ecosystem and fixing a problem they themselves created. The same thing can be done for São Paulo, by taking Santos’ example and making it even better to renew the river Tiete and Pinheiros.