Aura of Nature : Oceanography

Oceanography is the study of the physical, chemical, and biological features of the ocean, including the ocean’s ancient history, its current condition, and its future. In a time when the ocean is threatened by climate change and pollution, coastlines are eroding, and entire species of marine life are at risk of extinction, the role of oceanographers may be more important now than it has ever been.

Indeed, one of the most critical branches of oceanography today is known as biological oceanography. It is the study of the ocean’s plants and animals and their interactions with the marine environment. But oceanography is not just about study and research. It is also about using that information to help leaders make smart choices about policies that affect ocean health. Lessons learned through oceanography affect the ways humans use the sea for transportation, food, energy, water, and much more.

For example, fishermen with the Northwest Atlantic Marine Alliance (NAMA) are working with oceanographers to better understand how pollutants are reducing fish populations and posing health risks to consumers of the fish. Together, NAMA and ocean scientists hope to use their research to show why tighter pollution controls are needed.

Oceanographers from around the world are exploring a range of subjects as wide as the ocean itself. For example, teams of oceanographers are investigating how melting sea ice is changing the feeding and migration patterns of whales that populate the ocean’s coldest regions. National Geographic Explorer Gabrielle Corradino, a North Carolina State University 2017 Global Change Fellow, is also interested in marine ecosystems, though in a much warmer environment. Corradino is studying how the changing ocean is affecting populations of microscopic phytoplankton and the fish that feed off of them. Her field work included five weeks in the Gulf of Mexico filtering seawater to capture phytoplankton and protozoa—the tiniest, but most important, parts of the sea’s food chain.

Of course, oceanography covers more than the living organisms in the sea. A branch of oceanography called geological oceanography focuses on the formation of the seafloor and how it changes over time. Geological oceanographers are starting to use special GPS technology to map the seafloor and other underwater features. This research can provide critical information, such as seismic activity, that could lead to more accurate earthquake and tsunami prediction.

In addition to biological and geological oceanography, there are two other main branches of sea science. One is physical oceanography, the study of the relationships between the seafloor, the coastline, and the atmosphere. The other is chemical oceanography, the study of the chemical composition of seawater and how it is affected by weather, human activities, and other factors.

About 70 percent of Earth’s surface is covered by water. Nearly 97 percent of that water is the saltwater swirling in the world’s ocean. Given the size of the ocean and the rapid advancements in technology, there is seemingly no end to what can and will be uncovered in the science of oceanography.

When you say oceanography it is understood that it deals with the scientific study of the ocean. It includes a study of ocean ecosystems, ocean currents, waves, marine organisms, plate tectonics, seafloor geology and the ocean`s physical properties. According to a study and some informative documentation, it is said that 70% of the surface of the earth is covered by oceans. 

It consists of 5 major branches: 

1. Biological Oceanography
2. Chemical Oceanography
3. Geological Oceanography
4. Physical Oceanography
5. Paleoceanography

HISTORY BEHIND OCEANS ( Oceanography )

Though oceanography comes under the newest field of science, its root extended back several tens of thousands of years when people began to venture from their coastlines in rafts.

These seafaring explorers, navigators and oceanographers gave their utmost attention and researched oceans in many ways. Eventually,  these oceanographers observed waves, storms, tides and currents that carried their rafts in certain directions in various situations.

Nevertheless, the experience and understanding of these experts were passed down over thousands of years from generation to generation in myths and legends.

However, it wasn’t until about 2850 years ago (850 BC) that early naturalists and philosophers started trying to make sense of the enormous bodies of water they saw from land.

People all around the world strongly believed that the world is flat and not round. Maybe religiously or maybe scientifically.

Finally, it was the great Italian explorer Christopher Columbus who discovered that the world is not flat but round a sphere whose surface is nearly ¾ covered by the ocean in the late 1400s and 1500s.

Modern Oceanography concept began as a field of science a little less than 130 years back, in the late 19th century.

It was the Americans, Britishers and Europeans who launched expeditions to explore ocean currents, ocean life and the seafloor off their coastlines.

All of them started with ‘CHALLENGER EXPEDITION’ from 1872 to 1876 as the first expedition to explore the world’s ocean and seafloor. But this modern oceanography took off less than 60 years ago.

The advanced study led the world to the path of scientific belief.

Geological processes that occur beneath the waters of the sea affect not only marine life, but dry land as well. The processes that mold ocean basins occur slowly, over tens and hundreds of millions of years.

On this timescale, where a human lifetime is but the blink of an eye, solid rocks flow like liquid, entire continents move across the face of the earth and mountains grow from flat plains. To understand the sea floor, we must learn to adopt the unfamiliar point of view of geological time. Geology is very important to marine biology. Habitats, or the places where organisms live, are directly shaped by geological processes. The form of coastlines; the depth of the water; whether the bottom is muddy, sandy, or rocky; and many other features of a marine habitat are determined by this geology. The geologic history of life is also called Paleontology.

The presence of large amounts of liquid water makes our planet unique. Most other planets have very little water, and on those that do, the water exists only as perpetually frozen ice or as vapor in the atmosphere. The earth, on the other hand, is very much a water planet. The ocean covers most of the globe and plays a crucial role in regulating our climate and atmosphere. Without water, life itself would be impossible.

Our ocean covers 72% of the earth’s surface. It is not distributed equally with respect to the Equator. About two-thirds of the earth’s land area is found in the Northern Hemisphere, which is only 61% ocean. About 80% of the Southern Hemisphere is ocean.

CREDENCE OF OCEANS ( Oceanography )

• Scientists say that approximately 95% of the oceans are yet unexplored. They know more about moons and mars than they do about the ocean.
• It was Sir Benjamin Franklin, the first person to study the Gulf Stream scientifically.
• Earthquakes are natural disasters that take place all over the world but most of them are under the water of the oceans.
• Mid-Ocean Ridge is the longest mountain range in the whole world and it is located under the ocean.
• The first-ever textbook was written by Matthew Fontaine Maury in 1855. It was about oceanography called the PHYSICAL GEOGRAPHY OF THE SEA.
• Gold suspensions are a huge outcome of oceans. Mining them out from the seawater has not been possible yet.
• Documentation research says that the ocean’s coral reefs are ranked second in terms of the biodiversity of species. The world’s rainforest ranks first!
• Global warming is the major cause behind the melting of Antarctica resulting in rising sea levels.
• Analysis of seismic waves passing through the deep earth appears to confirm that an ocean of water is tied up in the mantle, 400 miles below the surface. Any voyager to the centre of the earth could leave the wet suit behind, however. The water is not liquid, but rather bound in minerals that exist at the extreme pressures found at such depths.
• The finding suggests that processes that occur in the shallower mantle and that cause volcanoes and related activity at the surface are also occurring farther down.
• “It’s a new view of the structure of this part of the earth,” said Brandon Schmandt, a geophysicist at the University of New Mexico and an author of a recent paper in the journal Science describing the research.
• The work also adds credence to the idea that the earth’s water accumulated in the interior during the planet’s formation, rather than arriving later through the bombardment of icy comets. In this view, water bound up in minerals in the mantle, the 1,800-mile-thick layer between the thin crust and the hot metallic core, degassed over time and reached the surface.
• The scientists studied a part of the mantle called the transition zone, from 300 to 440 miles deep. The ability of this zone to contain water — and apparently to retain a lot of it — “may have something to do with stabilising or buffering the size of the oceans,” said Steven D Jacobsen, a mineralogist at Northwestern University and another author of the paper. “It may be fortunate that the earth’s interior can act like a sponge.”
• Schmandt analysed seismic data from the US Array project, in which 400 mobile seismometers have been deployed across the US to create high-resolution images of the mantle. The analysis showed signs of melting in the transition zone, in areas where convection was causing the mantle to flow downward.
• Melting of the mantle occurs close to the surface, creating the magma that is responsible for volcanic hot spots around the world. The process is called dehydration melting, because as parts of the mantle slide deeper at places where the earth’s tectonic plates meet, the increasing pressure causes minerals in the mantle to release their water, lowering the melting temperature.
• But finding evidence of melting much farther down, as Schmandt did, was difficult to explain “unless you invoke water,” Jacobsen said. The work is all part of trying to understand how the dynamics of the deep earth affect what happens at the surface

EPILOGUE OF OCEANS ( Oceanography )

Alt: 200 million years old ocean; 

      Oceanographers had a scientific belief that the ocean floors are only about 200 million years old. Whereas, the continents are about 2-3 million years old. The effects of wind stress on the surface of the ocean have gone down through the water column by eddy viscosity and the energy is transferred to the water column. Water masses of different densities are produced due to different climates. Sea ice generation creates a lot of dense water masses in the polar region. The global circulation that has been set up due to differing densities of water which is drawn schematically as an ‘OCEAN CONVEYOR BELT’ redistributes large amounts of heat around the Earth.

• PRITISH PAUL

18/10/2023