What are the chemical properties of seawater?

Sander Casale
Oceanography

Station 1: An Introduction to Ocean Salinity

1.        Contrast the differences between brine, marine, brackish, lake (aquatic), and local tap water types based on salinity. Provide examples of where you find these water types. 

        Marine, brackish, lake, and tap water all have a different salinity. usually Marine water is the most dense, then Brackish, then lake and then tap water. 

2.       The average ocean salinity is 3.5% but there are areas higher or lower than this value. Name three oceanic locations that would differ from the average and explain what causes the variation to occur.

       3 oceanic locations that would differ from a regular ocean and its salinity would be in the arctic, the dead sea, and the Caribbean. The Caribbean's warm waters would make the sea water less dense, the opposite is true for  the arctic ocean because of its cold waters making the water more dense. Lastly the dead sea is a strange exception form regular oceanic examples because its is higher in salinity, which is about 34%. 

3.       Contrast the principles behind how a hydrometer and how a refractometer measure salinity.
    
       a hydrometer measures salinity using gravity in a slightly different way than a refractometer in the sense that the hydrometer does not use a dial to measure the salinity of water. Also, a refractometer is more reliable.

4.      Explain how the temperature of the water affects the salinity.

       Generally  saltier  waters are located in more warm regions, and cold water is more dense while warm water is less dense. 

5.       Which salinity-measuring tool would be easier to use in the field?

       a refractometer would be easier to use in the field because it is more stable and reliable. 

Station 2: The Effects of Temperature, Density, and Salinity

1.        From examination of your Station 2 plots, which seemed to have a greater effect on the density of water, temperature or salinity? Explain.

      Salinity appeared to have a greater effect in my salinity experiment. This is probably because the temperature of water can only reach a certain point until it is not water anymore, where as very polluted/salty  water can have a much higher salinity. 

2.       From the third graph plot of Station 2 (T-S Diagram), can the salinity stay the same while the temperatures and densities change? Explain.

       The salinity cannot stay the same while the temperature an density changes because temperature affects the salinity of water. 

Station 3: Water Mass Identification Using T-S Diagrams

1.        In the CTD profile you plotted, the deepest water had the lowest salinity. Explain how this is possible. Hint: Remember that more than salinity affects water density.

      Deeper water is generally colder than warm water and colder water is more dense, but surface pollutants as well as more salts make surface water denser.

2.       Normally you find high salinities at the surface of the water, especially in samples taken closer to the equator. Explain.

      Normally deserts are around 30 degrees longitude on the earth and in these places close to the equator is where the higher salinity is in the ocean. 

3.       Why would scientists be interested in identifying specific water masses?

       Scientists might be interested in identifying different water masses because these water masses might be present in specific places that they are interested in studying. 

Station 4: Factors affecting Salinity

1.        Examine the transect line and your plotted graph and explain what causes the salinity changes from the equator to the Bering Sea in the Arctic Circle.

2.       Research what other factors can alter the salinities in the ocean from its average of 35‰.

The value and importance of this activity

a.       What is the unique chemistry of seawater, how is it measured, what is its consistency and what are its physical characteristics?

      Seawater is denser than regular water and it is very abundant in our world. Seawater has different densities and salinities, and is vital for oceanic life.

b.      Why would scientists be interested in the inorganic chemistry of water? 

      It will help them be able to study sea life better by understanding the environment they live in. 

Molasses spill

After reading the article on the Honolulu harbor Molasses spill I was interested on how something like this could have happened. It said in the article that the molasses is soluble in the water so the tide will wash it away eventually. In the video posted to the article, there were a lot of dead fish and other organisms as well as a damaged coral reef system.
 People should respond to this problem by volunteering to clean up the beaches when ever possible and help support environmental teams that are working hard to clean up the molasses. In a situation like this I do not believe that anything could have been done to prevent this other than more secure shipping, because this incident was a freak accident. The only thing left to do is to continue cleaning up dead organisms and make the harbor safe for its organisms and people that rely on its water.

Photograph by Hugh Gentry, Reuters