Posted: June 19th, 2023

Earth Science: The Deep Sea

Earth Science: The Deep Sea
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The deep sea is one of the most fascinating and mysterious regions of our planet. It covers more than 70% of the Earth’s surface, but over 80% of it remains unexplored (Smithsonian Ocean, n.d.). In fact, we know more about the surface of Mars and the Moon than about the ocean floor on our own planet (Gerretsen, 2022). The deep sea is also home to a remarkable diversity of life forms, some of which could provide clues about what oceans on other planets could look like, and where we should search for alien life.

What is the deep sea?
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The deep sea is generally defined as the part of the ocean that lies below 200 meters (650 feet) of depth, where sunlight can no longer penetrate. It is divided into several zones, each with its own physical and biological characteristics. The mesopelagic zone, also known as the twilight zone, extends from 200 to 1,000 meters (650 to 3,300 feet) and receives only faint, filtered sunlight. Many animals in this zone have large eyes and bioluminescent organs to cope with the low light levels. The bathypelagic zone, also known as the midnight zone, extends from 1,000 to 4,000 meters (3,300 to 13,000 feet) and is completely dark. The temperature here is around 4°C (39°F) and the pressure is immense. Animals in this zone have reduced eyesight, slow metabolism, and often rely on chemosynthesis rather than photosynthesis for energy. The abyssopelagic zone, also known as the abyssal zone, extends from 4,000 to 6,000 meters (13,000 to 20,000 feet) and covers most of the ocean floor. The temperature here is around 2°C (36°F) and the pressure is crushing. Animals in this zone are mostly scavengers and detritivores that feed on organic matter that falls from above. The hadalpelagic zone, also known as the hadal zone, extends from 6,000 meters (20,000 feet) to the bottom of the deepest trenches and troughs in the ocean. The deepest point in the ocean is the Challenger Deep in the Mariana Trench, which reaches 10,994 meters (36,070 feet) below sea level (Smithsonian Ocean, n.d.). The temperature here is around 1°C (34°F) and the pressure is equivalent to a thousand atmospheres. Animals in this zone are highly adapted to extreme conditions and include worms, crustaceans, fish, and mollusks.

Why is the deep sea important?
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The deep sea plays a vital role in regulating the climate and maintaining the balance of life on Earth. The deep sea stores large amounts of carbon dioxide that would otherwise contribute to global warming. It also transports heat and nutrients around the globe through ocean currents that affect weather patterns and marine productivity. The deep sea hosts a rich biodiversity of organisms that have evolved unique adaptations to survive in harsh environments. Some of these organisms produce novel compounds that have potential applications in medicine, biotechnology, and industry. For example, enzymes from deep-sea bacteria have been used to improve laundry detergents and PCR tests (Gerretsen, 2022). The deep sea also provides valuable resources such as fish, minerals, oil, and gas that support human livelihoods and economies. However, these resources are often exploited unsustainably and pose threats to the health and integrity of the deep-sea ecosystems.

How do we explore the deep sea?
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Exploring the deep sea is challenging and costly due to its remoteness, darkness,
pressure, and complexity. Scientists use a variety of technologies and methods to study
the deep sea and its inhabitants. Some of these include:

– Submersibles: Manned or unmanned vehicles that can dive into the deep sea and carry
instruments, cameras, lights, and sampling devices. Examples include Alvin,
Nereus, Orpheus, Nautilus, Shinkai 6500, Jiaolong, etc.
– ROVs: Remotely operated vehicles that are tethered to a surface ship or platform
and controlled by operators on board or on shore. Examples include Jason,
Hercules-Argus-ROV system , ROPOS , etc.
– AUVs: Autonomous underwater vehicles that can navigate independently without a
tether or human intervention. Examples include Sentry , Seaglider , REMUS , etc.
– Landers: Platforms that are deployed from a ship or an aircraft and sink to
the bottom of the ocean, where they perform measurements, experiments, or
observations. Examples include HADES , AbyssBox , etc.
– Drifters: Floating devices that are carried by ocean currents and transmit data
via satellite. Examples include Argo , SOLO-TREC , etc.
– Moorings: Fixed or anchored devices that are deployed vertically in the water column
and measure physical, chemical, or biological parameters. Examples include
Deep-ocean Assessment and Reporting of Tsunamis (DART) , Ocean Observatories
Initiative (OOI) , etc.
– Satellites: Artificial satellites that orbit the Earth and collect data on the surface
of the ocean, such as temperature, salinity, color, height, etc. Examples include
SeaWiFS , MODIS , Jason-1/2/3 , etc.

What are the challenges and opportunities of deep-sea exploration?
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Deep-sea exploration faces many challenges, such as:

– Limited access and visibility: The deep sea is difficult to reach and observe due to its
depth, distance, and darkness. It requires specialized equipment and expertise that are
expensive and scarce. It also poses risks to human safety and health.
– High pressure and low temperature: The deep sea has extreme physical conditions that
affect the performance and durability of instruments and materials. It also limits the
survival and growth of organisms.
– Sparse and patchy data: The deep sea is vast and complex, but our knowledge of it is
limited and uneven. We have only explored a fraction of the deep-sea floor and sampled a
small number of its species. We also have gaps and uncertainties in our data sets and models.
– Environmental impacts: The deep sea is vulnerable to human activities that alter its
natural state and function. These include overfishing, pollution, mining, drilling,
climate change, etc. These impacts can have negative consequences for the deep-sea
ecosystems and services, as well as for human well-being and security.

However, deep-sea exploration also offers many opportunities, such as:

– Scientific discovery: The deep sea is a frontier of exploration and innovation that can
reveal new phenomena, processes, and organisms. It can also provide insights into the origin,
evolution, and diversity of life on Earth and beyond.
– Technological development: The deep sea is a testbed for developing and testing new
technologies and methods that can enhance our capabilities and efficiency in exploring
and monitoring the ocean. It can also inspire new solutions for engineering,
communication, energy, etc.
– Economic benefits: The deep sea is a source of valuable resources that can support
human development and prosperity. It can also create new markets and industries for
deep-sea products, services, and tourism.
– Societal benefits: The deep sea is a reservoir of cultural heritage that can enrich our
understanding of history, art, and identity. It can also foster education,
awareness, and stewardship of the ocean among the public.

Conclusion
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The deep sea is a fascinating and important part of our planet that deserves more attention
and appreciation. By exploring the deep sea, we can advance our scientific knowledge,
technological innovation, economic development, and societal well-being. However, we also need to protect the deep sea from human threats and ensure its sustainable use and management. The deep sea is not only our final frontier on Earth but also our gateway to outer space.

References
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Gerretsen, I. (2022). Why Nasa is exploring the deepest oceans on Earth. BBC Future Research paper writing help.
Retrieved from https://www.bbc.com/future/article/20220111-why-nasa-is-exploring-the-deepest-oceans-on-earth

Smithsonian Ocean (n.d.). The Deep Sea. Retrieved from https://ocean.si.edu/ecosystems/deep-sea/deep-sea

StudyCorgi (2022). Earth Science: The Deep Sea | Free Essay Example. Retrieved from https://studycorgi.com/earth-science-the-deep-sea/

Live Science (n.d.). Earth’s Final Frontier: Mysteries of the Deep Sea | Live Science.
Retrieved from https://www.livescience.com/30890-ocean-deep-mysteries-exploration.html