By Femi Akinola
Sea is a large body of salt water smaller than the ocean. It generally form part of , or connected with, an ocean or a larger sea. Around the world are the Mediterranean Sea, the Caribbean Sea, the Sea of Crete, Caspian Sea, the Sea of Galilee, Salton Sea, Baltic Sea, etc.
Ocean on its own is a large bodies of water separating the continents. According to researchers, ocean is occupying more than 70% of the earth surface area.
Scientists explained that oceans are not necessarily close to land. The smallest ocean is the Arctic Ocean, covering an area of 5.4 million square miles. Pacific Ocean is the largest of all existing oceans worldwide with an approximate size of 60 million square miles.
The closest ocean to Nigeria is the Atlantic. Lagos State is actually bounded in the south by the Atlantic Ocean. Other states in the country that shares border with Atlantic Ocean are – Akwa Ibom, Bayelsa, Cross River, Delta, Edo, Ogun, Ondo and Rivers State.
The Atlantic Ocean lies between North and South America on the West and Europe and Africa on the East. Up North, the Atlantic connects to the Arctic Ocean and to the Southern Ocean to the south. Scientists often divide the Atlantic into two basins: the North Atlantic and the South Atlantic.
Meanwhile, seas are relatively small in size and, in many cases they are at least partially enclosed by coastline. The largest sea is the Mediterranean Sea that separated Europe from Africa. It covers about 1.14 million square miles. Seas are usually located close to land.
Difference in depth / salinity
Seas are usually shallower than oceans, with an average depth of approximately 3,800 meters. At around 11.034 meters, the Challenger Deep in the Mariana Trench is the lowest point in the ocean. The shallow nature of seas lets in more sunshine and supports a wider variety of marine life.
Seas and oceans have different salinity levels as well. Seas often have higher salinity due to greater evaporation rates. Oceans on the other hand, have lower salinity because of their larger volume and the mixing of water from various sources.
Supportive of Marine life
Seas contain a broader variety of marine life because of their lesser depths and close proximity to land, which allow sunlight to penetrate more effectively. Seas provides substantial supplies of food for humans, mainly fish.
However, because oceans are deeper and further away from land, oceans sustain a greater diversity of creatures, mostly bacteria and microscopic plankton, in their marine ecosystems. Oceans have reduced aquatic life compared to seas due to lack of sunlight penetration and photosynthesis.
On Interconnectivity
Scientist further explained that seas may or may not be interconnected with other seas or oceans, but that all oceans are part of one global ocean, interconnected through currents and water circulation.
This interconnectivity, scientists noted, is demonstrated by phenomena like thermohaline circulation, which circulate seawater around the entire global ocean.
The only differences noted between seas and oceans are their size, depth, salinity, marine life as well their general interconnectivity.
They are bounded in the top by rivers or icecaps in many cases, and they are similar to an ocean, but far smaller and shallower.
They said seas tend to be saltier than oceans compared with other bodies of water, as well as quite dependent. This variety between seas and oceans has an important role in the study and management of such critical parts of the hydrosphere of our planet.
