The Ocean and Water

Colligative Properties

Salt changes the freezing point of ocean water dramatically, dropping it from 32 degrees Fahrenheit down to 28.4 degrees due to some colligative properties, properties that change independent of what a substance is (but not independent of the substance's concentration). Melting point and boiling point are both examples of colligative properties.

Ocean Minerals

The ocean has a vast amount of different chemicals within it.  While about 97% of the ocean is water, many salts also reside within it, dissolving and forming specific ions that float around in the water:

Ocean Acidification

In addition to the salts dissolved in ocean water, carbon dioxide is also dissolved into it since the surface of the ocean tries to maintain equilibrium with the carbon dioxide in the atmosphere. This carbon dioxide then transforms into carbonic acid, in turn lowering the pH of the ocean as a whole. Since the ocean is so large it is a good sink for materials like methane and carbon dioxide; lots of material can become trapped within its water for long periods of time.

As the pH of the ocean decreases a few issues arise:

• Marine life that create shells or use calcium carbonate for other structures require more energy to make those structures. This includes clams, oysters, mussels, crabs, starfish, urchins, and more. The process of creating these structures is known as calcification.

• Coral becoming bleached white and more fragile compared to nowadays. This can cause issues for the coral itself, the animals that live there, and less food for organisms that eat coral.

• Carbon dioxide in the water can also disrupt the entire marine food chain (and thus the carbon cycle) in multiple ways - phytoplankton use carbon dioxide for energy so they can become more abundant, shelled creatures are more damaged by their environments and easier to hunt, less shells will be available for animals on the ocean floor, and so forth.

Ocean Currents

Water within the ocean is constantly cycling throughout the world through ocean currents, areas of water that flow steadily in a particular direction and move a lot of energy and matter from one location to another. These currents can happen on both large and small scale as well as both deep within the ocean and near the surface.

Energy that enters the ocean via sunlight and heat can get sucked deep below the surface based on the movement of water within the oceans, trapping that heat and making the ocean work like a giant reservoir for heat energy and acting like a buffer for global temperature rises.

The ocean plays a huge role in the climate of different areas of earth. The uneven heating of ocean water, the large energy and mass transfer from the ocean, and other factors all come together to make certain areas more humid, create tropical storms and hurricanes, lead to droughts, and more. This is related to the energy cycle, water cycle, and carbon cycle amongst other global feedback loops.

Ocean and Plastics

The ocean is often polluted by many sources of trash entering it, especially plastic. Most plastic takes a long time to decompose and leads to many species having to adapt to survive within their usual habitats. This plastic eventually deteriorates over time due to erosion and sunlight weakening its structure, transforming it into microplastics, small plastic particles that float throughout the ocean (some pieces even too small to see with our eyes). These plastic pieces then cycle through the food chain with the potential to cause a wide variety of problems.

Making Fresh Water

While we lack freshwater in many locations and plastic pollution is rampant within the ocean we do have ways of purifying our water. This is especially important in areas that have trouble getting new (and clean) drinking water, such as deserts. 

Reusing our Water

Within wastewater treatment plants sewage undergoes multiple treatments in a row and then is reused. An example water treatment system is as follows:

In addition to these plants a lot of water can be reused in the form of greywater, taking water from households and office buildings and pumping them to different locations before being removed from the system as sewage. This is generally done with all pipes that aren't connected to wastewater from toilets.

Additional Resources

• What is Ocean Acidification?

• Ocean Acidification

• Ocean Driving Weather and Climate

• Wastewater Treatment

Interesting Links

• Is There a Quick Fix to Ocean Acidification?

• Production, Use, and Fate of All Plastics Ever Made

• The Arctic is Drowning in Plastic

• Plastic Pollution

• Great Pacific Garbage Patch