The Mariana Trench is the deepest known oceanic point on Earth. It is located in the western Pacific Ocean, to the east of the Mariana Islands. With a depth of approximately 10,994 meters (Challenger Deep), it is recorded as the lowest point on the ocean floor. The trench is about 2,550 kilometers long and has an average width of 69 kilometers.
Mariana Trench (Created by Artificial Intelligence)
Geological Structure and Formation Process
The Mariana Trench is the result of a subduction zone formed within the framework of oceanic tectonics, where the Pacific Plate is subducting beneath the Philippine Plate. In this process, the heavier and denser Pacific Plate slides beneath the lighter Philippine Plate, leading to the formation of the trench. Such tectonic events contribute to the continuous reshaping of the Earth's crust.
Mariana Trench (Created by Artificial Intelligence)
Depth Measurements and Research History
The first systematic depth measurement of the Mariana Trench was carried out in 1875 by the HMS Challenger, a research vessel of the British Royal Navy. During this expedition, a depth of approximately 8,184 meters was reported.
On January 23, 1960, Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh descended into Challenger Deep aboard the bathyscaphe Trieste. During this mission, they reached a depth of approximately 10,916 meters.
Throughout the 20th century, advancements in sonar technology and bathymetric mapping methods revealed that the trench exceeds a depth of 11,000 meters. In 2010, a multibeam sonar survey conducted by the U.S. National Oceanic and Atmospheric Administration (NOAA) in collaboration with the University of New Hampshire’s Center for Coastal and Ocean Mapping determined that the deepest point of the trench, Challenger Deep, lies at approximately 10,994 meters. This measurement is widely cited in contemporary scientific literature.
In 2012, Canadian filmmaker and marine explorer James Cameron made a solo descent to the same point in a custom-designed submersible named Deepsea Challenger. During this dive, various visual and physical data were collected regarding the trench's structure, biodiversity, and environmental characteristics.
James Cameron Reaches the Bottom of the Earth (euronews)
Biodiversity and Ecosystem
Despite extreme environmental conditions such as intense pressure (approximately 1,100 atmospheres), low temperatures (0–2 °C), and constant darkness, biological life has been detected in the Mariana Trench. In particular, barotolerant microorganisms (pressure-resistant bacteria), some multicellular invertebrates, and extremophile species inhabit various depths of the trench. Most of the organisms discovered rely on chemosynthetic processes for nutrition—obtaining energy from chemical reactions instead of sunlight.
The study of species inhabiting these environments provides new perspectives on the potential for extraterrestrial life forms and on understanding the biological limits of ocean ecosystems. Microorganisms found especially in deep-sea sediments are also significant for biotechnological applications such as antibiotic production.
Scientific Importance and Ongoing Research
The Mariana Trench holds great scientific importance not only for its geological and biological characteristics but also for its role in understanding climate processes. Deep ocean trenches serve as final deposition zones for organic material, which plays a critical role in Earth's carbon cycle. Therefore, the function of deep-sea areas as carbon sinks is being studied in detail within the scope of global climate change research.
International research institutions such as NASA, NOAA (National Oceanic and Atmospheric Administration), and JAMSTEC (Japan Agency for Marine-Earth Science and Technology) are conducting ongoing monitoring and studies in many areas including high-resolution mapping of the trench, water chemistry analyses, biological sampling, and microplastic density assessment.
Legal Status and Protected Area
Under the United Nations Convention on the Law of the Sea (UNCLOS), the Mariana Trench is considered part of the high seas. Therefore, it does not fall under the sovereignty of any single nation, but various environmental protection measures have been developed in the context of international environmental law.
In 2009, the United States designated a specific portion of the trench as the Mariana Trench Marine National Monument, placing the area under environmental protection. Under this designation, commercial fishing, mining, and other human activities are restricted. These conservation policies are important for the sustainability of marine ecosystems.
