Marine vents
Marine vents, also known as deep-sea hydrothermal vents, are geological formations located along deep fractures in the seafloor, specifically associated with mid-ocean ridges. These ridges are undersea mountain ranges characterized by active volcanism. At depths exceeding 2 kilometers, marine vents are created when cold seawater seeps into fractures, encounters heated rocks near magma, and becomes enriched with dissolved minerals. This process leads to the emergence of hot, mineral-laden water that can create features resembling geysers, often referred to as "black smokers" due to the dark, smoky appearance of the venting water as minerals precipitate out upon cooling.
The unique conditions around marine vents support diverse biological communities that thrive without sunlight, relying instead on bacteria that obtain energy through chemosynthesis. These communities can include surprisingly large organisms, such as tube worms that may grow over 3 meters in length. The life around these vents is highly dependent on their activity; when vents become inactive, the associated ecosystems collapse. While marine vent organisms may not be a direct food source for humans, they are of interest for their potential medicinal properties. Despite the challenges in accessing these remote environments, marine vents are significant subjects of scientific research, providing insights into geology, biology, and oceanography.
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Marine vents
Marine vents are localized areas of the seafloor where cold seawater interacts with magma. The result of this interaction produces spectacular eruptions of hot seawater and enables the precipitation of sulfide minerals of iron, copper, and zinc.
Definition
Marine vents, more commonly known as deep-sea vents, are produced along deep fractures in the seafloor. These fractures are associated with the mid-ocean ridges. The mid-ocean ridges are undersea mountain ranges that are sites of active volcanism. Despite their association with undersea volcanic mountain ranges, all marine vents occur at depths greater than 2 kilometers below the surface. Marine vents are studied primarily by deep submersible vehicles.
Overview
Marine vents are formed when fractures in the seafloor develop and cold water flows in from above. As the seawater flows deeper into the fractures, it may encounter rocks heated by close proximity to magma; the rocks heat the seawater. The heated water begins to dissolve minerals from the surrounding rocks, and its chemistry changes from that of common seawater. If a critical temperature is reached, the hot water will rush to the surface. Although their appearance suggests an explosive volcanic eruption on land, marine vents are more like geysers than volcanoes.
As the hot seawater exits the vent, it begins to cool rapidly. Minerals that are in solution begin to precipitate out. This precipitation may give a dark, smoky appearance to the hot water exiting the marine vent. The name “black smoker” is commonly applied to these vents. The minerals that commonly precipitate out in these vents are metal sulfides (combinations of a metal and sulfur). The most common minerals found are sulfides of iron, copper, and zinc. These minerals form crusts around the opening and may precipitate into a tall “chimney” of minerals around the marine vent.
Marine vents are also the site of unique biologic communities. These communities thrive in the total absence of sunlight. The is based on bacteria that derive their energy from chemosynthesis. This process enables the bacteria to derive their energy from chemicals dissolved in the hot water exiting the marine vents. Other animals depend on the bacteria. Some animals associated with the vent communities grow to very large sizes. Tube worms around marine vents may be larger than 3 meters in length. Because the communities depend on the vent waters for their source of energy, the animals live closely packed around the vent. When vents become inactive, the communities die. While not a likely source of food for humans, it has been suggested that the vent animals may contain unusual chemicals that may help develop new medicines.
There is a great deal of difficulty and expense involved in reaching deep marine vents. This fact, plus the cost of bringing minerals and animals to the surface and shipping them to shore, must be considered in deciding whether it is feasible to use these valuable resources. Despite the obstacles, marine vents remain the focus of much geologic, biologic, and oceanographic research.
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"Deep Sea Hydrothermal Vents." National Geographic, 19 Oct. 2023, education.nationalgeographic.org/resource/deep-sea-hydrothermal-vents/. Accessed 23 Dec. 2024.
Menini, Elisabeth, et al. "Towards a Global Strategy for the Conservation of Deep-Sea Active Hydrothermal Vents." npj Ocean Sustainability, vol. 2, no. 22, 27 Nov. 2023, doi.org/10.1038/s44183-023-00029-3. Accessed 23 Dec. 2024.