The oceans, which cover approximately 75% of the earth’s surface, are essential for both the planet and its inhabitants. They provide vital resources such as food and natural materials, while also serving as a recreational outlet for many individuals. Ensuring the preservation of the oceans is crucial for marine life and terrestrial creatures’ survival. By safeguarding the unique habitats within the ocean, we can enhance the well-being of all living beings on earth. Ocean pollution is a significant concern that not only affects the ocean itself but also has consequences for our entire planet. It directly harms marine organisms and indirectly impacts human health and resources. Pollution sources like oil spills, toxic waste, and improper disposal of harmful materials contribute significantly to this problem.
The significance of comprehending ocean pollution lies in its connection to discovering solutions. By raising awareness about ocean pollution, individuals acquire knowledge on how to prevent it.
When solar radiation, including both light and heat, reaches the ocean, a majority of it is absorbed within the first few tens of meters of water. The heat is quickly distributed downward due to waves and turbulence. Thus, the surface layer of the ocean undergoes thorough mixing throughout its entirety.
The temperature of this mixed layer primarily varies based on latitude. For instance, high latitude regions like the polar seas can have temperatures as low as -2 degrees Celsius (28.4 degrees Fahrenheit), while low latitude areas such as the Persian Gulf can reach warm temperatures of 36 degrees Celsius (96.8 degrees Fahrenheit). On average, ocean surface waters maintain a temperature around 17 degrees Celsius (62.6 degrees Fahrenheit).
The thermocline is a boundary that separates the ocean’s surface waters from the deeper unmixed layers. It typically starts at a depth of 100-400 meters and extends further down for several hundred meters. Within this region, there is a rapid decrease in temperature. The deep ocean, known as the area beneath the thermocline, makes up around 90% of the ocean’s total volume and has temperatures that reach approximately 0 degrees Celsius. On the other hand, surface waters can be warm and enjoyable for activities like swimming at around 20 degrees Celsius. However, most of our ocean water has temperatures ranging from 0-3 degrees Celsius (32-37.5 degrees Fahrenheit).
The density of ocean water increases as temperature decreases until it freezes. Ocean water, with an average salinity of 35 psu, freezes at -1.94 degrees Celsius (28.5 degrees Fahrenheit). At high latitudes, ocean water can reach these low temperatures and freeze. Dissolved salts are rejected by the forming ice, making sea ice only about 1% salt. It is interesting to note that melted sea ice would be drinkable due to the reduced salt content, unlike seawater. The formation of sea ice at high latitudes influences the circulation of deep ocean waters. Temperature measurements at the ocean surface are often taken using thermometers on buoys. The Argo program now monitors the state of ocean surface waters worldwide.
The Argo program is deploying floats that measure salinity and temperature throughout the surface layer of the ocean. By 2003, a total of 3,000 floats will have been deployed all over the ocean. Each float is programmed to sink 2,000 meters down and drift at that depth for approximately 10 days. During this time, temperature and salinity are continuously measured. Once the float reaches the surface, data is transmitted to a satellite, allowing scientists to access the state of the ocean within hours of data collection. The lifespan of each float is expected to be 4-5 years. In deeper parts of the water, in situ measurements are often conducted using a CTD instrument, which is placed in the ocean water from either a ship or a platform.
