An ocean vent sits over a deep fissure in the ocean floor. Ocean vents eject hot, often toxic, fluids and gases into the surrounding seawater. They often mark sites of tectonic activity, and create some of the most hostile habitats on Earth.Ocean vents are a type of hydrothermal vent. Other types of hydrothermal vents include hot springs, geysers, and fumaroles. As their name indicates, all hydrothermal vents are characterized by water (hydro-) and extremely high temperatures (thermal).Tectonic ActivityOcean vents are the product of tectonic activity beneath the ocean floor. Tectonic activity describes the way tectonic plates, giant slabs of Earth’s lithosphere, interact with each other.Ocean vents are found in all ocean basins, although they are most abundant around the Pacific Ocean’s “Ring of Fire,” which also includes active earthquake zones, volcanoes, and ocean trenches.Ocean vents are primarily found around mid-ocean ridges and volcanic arcs. At both mid-ocean ridges and back-arc basins, the molten magma of Earth's asthenosphere wells up close to the surface.Mid-ocean ridges form at divergent plate boundaries, where tectonic plates are moving apart from each other. New oceanic crust is formed at mid-ocean ridges. The Mid-Atlantic Ridge, for instance, runs through the entire Atlantic Ocean, separating the North American and Eurasian plates in the north and the South American and African plates in the south. Ocean vents dot the entire underwater mountain range.Volcanic arcs form at convergent plate boundaries, where a dense tectonic plate is falling beneath a less-dense plate in a process called subduction. Oceanic crust is being destroyed in the subduction zones around volcanic arcs. Volcanic arcs may include volcanoes that rise above sea level, such as Japan’s Ryuku Islands, while some volcanic arcs are seamounts, or underwater mountains.Ocean vents found around volcanic arcs are located on the overriding (less-dense) tectonic plate. This area is called a “back-arc basin.” Back-arc basins are formed as the ocean trench created by subduction migrates “backward” toward the subducting plate in a process called trench rollback. Trench rollback causes the overriding plate to be stretched thin, creating conditions that allow for the formation of ocean vents.Going with the FlowThe process that creates ocean vents takes place in three zones: the recharge zone, the reaction zone, and the upflow zone.Vent fluid in the recharge zone is formed by seawater seeping into cracks in the seafloor. As the seawater is warmed by its proximity to magma, it is stripped of its magnesium.At this point, seawater changes to an acidic vent fluid. As an acid, the vent fluid leeches more metals from surrounding rocks of the oceanic crust.The acidic vent fluid continues to heat up as it flows and seeps toward the vent’s source of heat. The closer magma wells to the fluid, the warmer the fluid becomes and the quicker its chemical reaction time will be.Chemistry and vent outflow are also influenced by the vent fluid’s residence time, or the time it spends in the region close to the heat source.The vent fluid becomes more buoyant in the reaction zone and races back toward the surface. Incoming flows of vent fluid may also push the superheated fluid upward toward the seafloor. Vent fluid has the least amount of time in this upflow zone.The vent fluid’s temperature drops slightly as it races away from the vent’s heat source. Vent fluid can lose heat in three major ways. First, heat can dissipate into the surrounding rocks. Second, it can mix with cold seawater seeping in from above. Both of these methods involve a transfer of heat (from the vent fluid to either rocks or seawater). This process is called conductive cooling.The third way a vent fluid can lose heat is through decompression. Unlike the interaction of vent fluid with rocks or seawater, decompression does not involve a transfer of heat. The fluid cools through a loss of pressure. (Pressure is higher in the reaction zone, which lies deeper in the Earth.) This process is called adiabatic cooling.Ejection SitesHydrothermal vents are where the hot, toxic vent fluids from the upflow zone are spewed from oceanic crust into the surrounding seawater. Hydrothermal vents are narrow and well-sealed, and vent fluids exit at high velocity.Upon contact with the cold, dense ocean, the vent fluid “precipitates” minerals such as sulfates, sulfides, and quartz. These minerals often give ocean vents their characteristic color.Not all vent fluids are violently ejected into seawater from hydrothermal vents, however. Diffuse flows form in areas where vent fluids mix with cold seawater before exiting the seafloor.Diffuse flows usually cover a larger portion of a vent field than narrow hydrothermal vents. Vent fluids exiting through diffuse flows are usually cooler, less toxic (from mixing with seawater), and exit into the ocean more slowly over a larger area. Diffuse flows also lack the telltale “smoke” of gushing hydrothermal vents.PlumesAs vent fluid is ejected into the ocean, it forms a hydrothermal plume. This plume is more buoyant than seawater, and continues to rise.As it rises and expands, the plume constantly mixes with seawater and its chemistry is diluted. Eventually, the plume reaches neutral buoyancy (the point where the pressure inside the plume equals the pressure of the surrounding seawater, and the plume no longer rises or sinks). At neutral buoyancy, the plume and its chemistry are entirely dispersed by ocean currents.Vent ChemistryThe chemistry of ocean vents has an enormous impact on the chemistry of the ocean. At mid-ocean ridges, ocean vents help cool new oceanic crust. At volcanic arcs, they contribute to the geology of the seafloor and even underwater mountains.Temperatures at vent fields range from below 50° Celsius (122° Fahrenheit) to more than 400° Celsius (752° Fahrenheit). Some ocean vents are rich in oxygen and oxygen compounds (such as sulfates), while others are anoxic. Some are highly acidic, with a pH as low as 2. Others have a pH as high as 8.The temperature and chemistry of vent fields varies across the ocean, and these factors are influenced by such features as the frequency of volcanic eruptions in the area, the presence and quantity of sediments, the permeability of the seafloor, the composition of rocks in the oceanic crust, the depth of the heat source, the residence time of vent fluids in the reaction zone, and the water-to-rock ratio at the reaction zone.TemperatureOcean vents help cool the Earth’s interior. In fact, oceanographers and geologists estimate that ocean vents account for a whopping 10% of total heat loss from Earth’s mantle and core.The temperature of vent fluid is always warmer than the surrounding seawater. Seawater at the deepest ocean vents is just above freezing at 2° Celsius (35° Fahrenheit). Energy from the Earth’s superheated mantle and core can heat vent fluid to temperatures of more than to 400° Celsius (752° Fahrenheit). Around diffuse flows, the temperature of vent fluids is usually below 50° Celsius (122° Fahrenheit).The temperature of a vent fluid, and the temperature difference between the vent fluid and surrounding seawater, can determine the chemistry of a vent.For instance, most hydrothermal vents eject vent fluids that would boil at ambient temperatures at sea level. However, at great depths and great temperatures, phase separation (the separation of a liquid into two distinct liquids) prevents vent fluids from boiling. Instead, the chemical reaction between seawater and vent fluid forms a high-salinity brine. This chemical reaction is called brine condensation.ChemicalsThe most characteristic feature of ocean vents is probably the dense particle plumes that inject chemicals into seawater. Vent fluids most often include sulfides and sulfates. Sulfides are negatively charged ions of the mineral sulfur, while sulfates are negatively charged ions of sulfur-oxygen molecules.Sulfides and sulfates exist in a dazzling array at ocean vents: calcium sulfate, strontium sulfate, zinc sulfide, iron sulfide, copper sulfide, iron sulfide, manganese sulfide. These compounds interact with other elements, including hydrogen, helium, potassium, gold, silver, and cadmium. Perhaps most crucially, vent fluids interact with sodium and chloride, forming salt.As ocean vents eject mineral-rich fluids into the ocean, many of these minerals precipitate, or solidify. Tall, thin vent chimneys are made of these precipitated minerals, including copper, iron, zinc, cadmium, silver, and even gold.As long as they continue to eject fluid, the chimneys continue to grow. Some chimneys can grow 30 centimeters (almost 12 inches) a day and reach 20 meters (65 feet) tall. Tall chimneys don’t last long, though. The mineral structure is fragile. Powerful undersea currents and pressure often lead to their collapse.Types of Ocean VentsOcean vents can be classified as black smokers, white smokers, or snowblowers. All these ocean vents form in the same way. Their differences are marked by color, temperature, and chemistry.Black smokers are the largest type of ocean vent, and eject the hottest fluids. Vent fluids spew out of tall chimneys at rates of up to 5 meters per second (16 feet per second). The “smoke” blown from black smokers is a dense cloud of particles, mostly metals such as iron and copper. The metals in the fluid mix with the oxygen in the seawater to form a black cloud.White smokers generally develop over cooler vents. White smoker fluid is generally more acidic, and chimneys have much higher ratios of minerals such as zinc, cadmium, silver, and gold.Snowblower vents develop around low-temperature diffuse flows, often around lava from underwater volcanoes. Snowblowers earn their nickname by ejecting columns of white, fluffy particles.Unlike the particle plumes of black and white smokers, snowblower particles are not minerals. The ejecta from snowblower vents are made up of billions of tiny, organic microbes. The heat and minerals present in lava interact with seafloor communities of bacteria and archaea, producing flocculent microbial blooms.Ocean Vent CommunitiesMany unique organisms are adapted to life in the harsh environment of an ocean vent. In fact, ocean vents set the current highest temperature possible for life to exist—a fiery 121° Celsius (250° Fahrenheit), found on the Endeavor hydrothermal vents on the Juan de Fuca ridge off the coast of Vancouver, British Columbia, Canada.The producers in ocean vent food webs are extremophiles. Extremophiles thrive in chemically extreme conditions that usually discourage life on Earth. Most food webs on Earth, for instance, rely on the sun. Producers near Earth’s sunlit surface (such as green plants and phytoplankton) use sunlight, water, and carbon dioxide to manufacture simple sugars and oxygen in a process called photosynthesis.Organisms near an ocean vent do not always have access to sunlight. These organisms depend on a process called chemosynthesis. In chemosynthesis, microbes convert vent fluids such as hydrogen sulfide into energy (simple sugars), water, and sulfur. Sulfur is naturally a yellow, and many bacterial mats have a characteristic golden color as a result.These specialized microbes (mostly bacteria and archaea, single-celled organisms similar to bacteria) live everywhere in the vent community. They live on the vent floor. They live inside chimneys. They even live inside animals like tube worms and mussels. These microbes are the basis of food webs in the ocean vent ecosystem. Tube worms, mussels, and clams use the microbes to produce nutrients. Plankton and shrimp eat the microbes. In turn, predators like crabs, fish, jellies, and octopuses prey on these animals.The deep ocean is often so dark that many creatures do not have functioning eyes. Their bodies are often gelatinous and lightweight, to offset the crushing pressure of the deep.Ocean vents provide an “oasis” of biological activity on the ocean floor, which is often dominated by abyssal plains. For this reason, ocean vents have one of the highest rates of biomass of any habitat on Earth. Busy, clustered communities of organisms thrive around the vents, while hardy bacterial mats stretch out meters wider.Exploring Ocean VentsIn 1977, oceanographers, led by National Geographic Explorer-in-Residence Robert Ballard, were exploring the Galápagos Rift along the mid-ocean ridge in the eastern Pacific.The scientists noticed a series of temperature spikes in their data. They wondered how deep-ocean temperatures could change so drastically over such a short distance—from near-freezing to 400°C (750 °F). Ballard and his crew quickly sent cameras to the seafloor to investigate the anomaly.What they discovered, of course, were ocean vents. Fascinated by these undersea features, oceanographers used a submersible to study the vents themselves. They were even more fascinated to discover a diverse, thriving community of living organisms. Until this point, all life on Earth was considered to be dependent on sunlight.Today, oceanographers use an array of instruments to study ocean vents. Bathymetric maps of the seafloor and interactive maps of ocean currents help them identify hydrothermal plumes rising through the ocean. Plumes may be identified through their temperature, chemical structure, and even their color.One of the innovative ways to identify and study ocean vents is the “tow-yo.” A tow-yo is attached to a research vessel and a collection of sophisticated instruments (called a conductivity-temperature-depth package). The tow-yo raises and lowers the instruments—just like a yo-yo—within a few hundred meters of the water column. This allows oceanographers to determine the shape of the plume and help pinpoint the vent field from which it came.Once a vent field is located, oceanographers use both ROVs and manned vehicles to study ocean vents up-close and personal. In fact Alvin, the sub originally used by Ballard and his team in the 1970s, is still one of the most effective ways scientists investigate the geological, chemical, and biological characteristics of ocean vents. Most vents are far too deep—under far too much pressure, with far too many toxic fluids penetrating the water—to allow study by divers.These manned and unmanned vehicles collect samples—of the seafloor itself, chimneys, bacteria, and even fish.Benefits of Ocean VentsOcean vents are one of the primary determinants of ocean chemistry. (Other major contributors include runoff from rivers and atmospheric changes in the air.)The ocean’s salinity, for example, was not fully understood until ocean vents were discovered in the 1970s. Prior to the discovery, most oceanographers suspected the ocean was salty due to sediments deposited by rivers and streams. Today, we know the ocean is salty because ocean vents eject chemicals directly in the water column.While ocean vents help explain how chemicals such as salt are added to seawater, they can also help explain how chemicals are taken out. For decades, for example, oceanographers could not explain how the concentration of magnesium in the ocean remained constant. Magnesium was being added to seawater from terrestrial sources, but the chemistry of the ocean remained the same. The discovery of ocean vents solved the mystery: Volcanic rocks in the recharge and reaction zones extract magnesium from seawater. The water coming out of the vents has virtually no magnesium in it.While ocean vents contribute to the ocean’s chemistry, their profound heat only slightly influences ocean temperatures. The reason is that while vent fluids are super-hot, they are super-cooled by the tons of cold water surrounding them. In fact, beyond a meter (3 feet) of a vent, the water is back to a near-freezing 1.7° Celsius (35° Fahrenheit).Industrial ApplicationsThe unusual properties of ocean vents may influence concepts developed by chemical and industrial engineers in a process called biomimicry. Biomimicry is the process of using the natural world as a guide to develop new technologies.Chemosynthetic bacteria, for instance, may influence the way pharmaceutical companies develop antibiotics and enzymes that combat diseases or injuries.Chemosynthetic bacteria, which convert toxic chemicals to harmless substances, may also provide resources to help clean up hazardous waste or toxic spills in the ocean.Finally, biomimicry may guide engineers to develop ways for machinery to better withstand heat, toxicity, or intense pressure.MiningOcean vents are surrounded by seafloor massive sulfide (SMS) deposits. SMS deposits are minerals that harden as vent fluid interacts with seawater.SMS deposits can be material left over from collapsed chimneys or even chimneys themselves. They contain metals such as copper, iron, zinc, lead, silver, and gold. These metals are valuable for human industry and can be sold for high prices.Mining companies have studied ways to extract SMS deposits from the deep ocean. Seafloor mining is a complicated and expensive procedure. The environmental impact is enormous. Microbes and animals are destroyed or displaced as the seafloor is disrupted.The waters surrounding Papua New Guinea in the South Pacific are rich in SMS deposits. The world’s first major SMS mining operation is expected to begin extraction in this area by 2017.
The planet Jupiter's moon Europa is probably covered by a huge, ice-capped ocean. Scientists have guessed that Europa's ocean may hide hydrothermal vents . . . and those vents may be the most likely spot for extraterrestrial life in our solar system.Homer Simpson is HotJust like mountains, vents have individual names. Some vents are named by the scientists who discover them, some are named for geographic features (such as the onion domes of the Kremlin vent field), and some are just fun.• Godzilla, Sasquatch, Salty Dawg (North Pacific Ocean)• Champagne (Caribbean Sea)• Homer Simpson, Scooby, Tweety (South Pacific Ocean)• Snake Pit, Lucky Strike, the Kremlin (Atlantic Ocean)• Kairei, Edmond (Indian Ocean)Why is the Ocean Salty?Oceanographers deflected the question until the 1970s. Find out why in this delightful “campfire story” with Robert Ballard.Rotten RocksHow did one scientist describe the snow-white shrimp covering a black smoker? “They look like maggots on a piece of rotting meat!”Mechanic’s GarageMost research vessels have enough spare parts to rebuild an entire submersible! When you’re out to sea investigating ocean vents and other seafloor features, you can’t just go to your local hardware store to pick up a new gadget.Chemosynthetic CommunitiesChemosynthetic communities are not limited to ocean vents, or even the ocean. These communities, which can function without sunlight, have been documented at cold seeps, in whale carcasses, and in shipwrecks. On land, chemosynthetic communities thrive in the hot, toxic hydrothermal vents that create hot springs and fumaroles.AnhydriteAnhydrite, the mineral that makes up the chimneys of black smokers, is actually not black—it’s white before it interacts with other particles in vent fluid and precipitates in a ring around the vent.
Term Part of Speech Definition Encyclopedic Entry abundant Adjective
in large amounts.
abyssal plain Noun
extensive, featureless region of the deep ocean floor.
chemical compound that reacts with a base to form a salt. Acids can corrode some natural materials. Acids have pH levels lower than 7.
to adjust to new surroundings or a new situation.
having to do with a process or chemical reaction that occurs without the gain or loss of heat.
layer of gases surrounding Earth.
Encyclopedic Entry: air Alvin Noun
(1964-present) deep-sea research submersible owned by the U.S. Navy and operated by the Woods Hole Oceanographic Institution.
having to do with the surrounding area or environment.
(CaSO4) grey-white mineral found in sedimentary rocks. Also known as anhydrous calcium sulfate.
unusual occurrence or abnormality.
no oxygen in the environment.
substance that can stop or slow the growth of certain microbes, such as bacteria. Antibiotics do not stop viruses.
archaea Plural Noun
(singular: archaeon) a group of tiny organisms often living in extreme environments, such as ocean vents and salt lakes.
layer in Earth's mantle between the lithosphere (above) and the upper mantle (below).
layers of gases surrounding a planet or other celestial body.
Encyclopedic Entry: atmosphere back-arc basin Noun
depression on the ocean floor formed as an ocean trench created by subduction migrates “backward” toward the overriding plate.
bacteria Plural Noun
(singular: bacterium) single-celled organisms found in every ecosystem on Earth.
Encyclopedic Entry: Bacteria bacterial mat Noun collection of microorganisms in which cells adhere to each other or to a surface. Also called a microbial mat, biofilm, or slime (although distinct from actual slime molds). bathymetric map Noun
representation of spatial information displaying depth underwater.
having to do with the study of life and living organisms.
living organisms, and the energy contained within them.
process of using models, systems, and elements of nature as a guide for developing new technology.
black smoker Noun
type of ocean vent that ejects black mineral fluid (not smoke) into the surrounding water.
to change from a liquid to a gaseous state.
water saturated with salt. Brine also refers to oceans and seas, and their water.
brine condensation Noun
chemical reaction between seawater and vent fluid that forms a high-solidity brine.
capable of floating.
physical, cultural, or psychological feature of an organism, place, or object.
chemical reaction Noun
process that involves a change in atoms, ions, or molecules of the substances (reagents) involved.
process by which some microbes turn carbon dioxide and water into carbohydrates using energy obtained from inorganic chemical reactions.
tall structure composed of minerals ejected from vents along the ocean floor.
to gather together in small groups based on certain characteristics.
to fall apart completely.
to make more complex, difficult, or detailed.
measure of the amount of a substance or grouping in a specific place.
able to transmit something, such as electricity or heat.
convergent plate boundary Noun
area where two or more tectonic plates bump into each other. Also called a collision zone.
to change or to be changed.
to change or to be changed.
the extremely hot center of Earth, another planet, or a star.
Encyclopedic Entry: core crew Noun
workers or employees on a boat or ship.
data Plural Noun
(singular: datum) information collected during a scientific study.
amazing or extremely impressive.
gradual reduction in atmospheric pressure.
having parts or molecules that are packed closely together.
to ruin or make useless.
influencing agent or factor.
diffuse flow Noun
an area of the sea floor that forms due to a low-temperature, slow-moving ocean vent.
to weaken or reduce.
to disapprove or encourage someone not to do something.
to scatter or spread out widely.
to remove or force to evacuate.
to scatter and disappear.
divergent boundary Noun
area where two or more tectonic plates are moving away from each other. Also called an extensional boundary.
varied or having many different types.
to overpower or control.
severe or extreme.
the sudden shaking of Earth's crust caused by the release of energy along fault lines or from volcanic activity.
community and interactions of living and nonliving things in an area.
Encyclopedic Entry: ecosystem effective Adjective
useful or able to perform a task.
to get rid of or throw out.
material ejected from a crater, usually by an erupting volcano or meteorite impact.
person who plans the building of things, such as structures (construction engineer) or substances (chemical engineer).
conditions that surround and influence an organism or community.
environmental impact Noun
incident or activity's total effect on the surrounding environment.
proteins produced in living cells that act as catalysts to accelerate the vital processes of an organism.
to guess based on knowledge of the situation or object.
pre-eminent explorers and scientists collaborating with the National Geographic Society to make groundbreaking discoveries that generate critical scientific information, conservation-related initiatives and compelling stories.
to pull out.
microbe that is adapted to survive in very harsh environments, such as freezing or boiling water.
to cause an interest in.
narrow opening or crack.
having fluffy, cloud-like, soft particles.
material that is able to flow and change shape.
food web Noun
all related food chains in an ecosystem. Also called a food cycle.
Encyclopedic Entry: food web fragile Noun
delicate or easily broken.
rate of occurrence, or the number of things happening in a specific area over specific time period.
vent from which steam is emitted.
to work or work correctly.
state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.
resembling or behaving like a jelly, gel, or gelatin.
study of the physical history of the Earth, its composition, its structure, and the processes that form and change it.
natural hot spring that sometimes erupts with water or steam.
Encyclopedic Entry: geyser gush Verb
to flow suddenly and forcefully.
environment where an organism lives throughout the year or for shorter periods of time.
Encyclopedic Entry: habitat hardy Adjective
strong or able to withstand severe weather.
hazardous waste Noun
manufacturing byproduct that is toxic or harmful to people and the environment.
confrontational or unfriendly.
hot spring Noun
small flow of water flowing naturally from an underground water source heated by hot or molten rock.
hydrothermal plume Noun
vent fluid ejected into the ocean.
hydrothermal vent Noun
opening on the seafloor that emits hot, mineral-rich solutions.
to recognize or establish the identity of something.
meaning or effect.
to display or show.
activity that produces goods and services.
force that effects the actions, behavior, or policies of others.
to force something (usually a liquid) into a cavity or tissue.
to invent or introduce something new.
new, advanced, or original.
to study or examine in order to learn a series of facts.
electrically charged atom or group of atoms, formed by the atom having gained or lost an electron.
molten rock, or magma, that erupts from volcanoes or fissures in the Earth's surface.
carnivorous or bloodsucking worm.
outer, solid portion of the Earth. Also called the geosphere.
Encyclopedic Entry: lithosphere machinery Noun
mechanical appliances or tools used in manufacturing.
molten, or partially melted, rock beneath the Earth's surface.
Encyclopedic Entry: Magma's Role in the Rock Cycle magnesium Noun
chemical element with the symbol Mg.
carrying one or more people.
middle layer of the Earth, made of mostly solid rock.
Encyclopedic Entry: mantle metal Noun
category of elements that are usually solid and shiny at room temperature.
tiny organism, usually a bacterium.
mid-ocean ridge Noun
underwater mountain range.
to move from one place or activity to another.
nutrient needed to help cells, organs, and tissues to function.
process of extracting ore from the Earth.
smallest physical unit of a substance, consisting of two or more atoms linked together.
solid material turned to liquid by heat.
neutral buoyancy Noun
condition in which an object's density is equal to that of the fluid in which it is emerged.
substance an organism needs for energy, growth, and life.
Encyclopedic Entry: nutrient oasis Noun
area made fertile by a source of fresh water in an otherwise arid region.
Encyclopedic Entry: oasis ocean basin Noun
depression in the Earth's surface located entirely beneath the ocean.
ocean current Noun
continuous, predictable, directional movement of seawater.
oceanic crust Noun
thin layer of the Earth that sits beneath ocean basins.
person who studies the ocean.
ocean trench Noun
a long, deep depression in the ocean floor.
Encyclopedic Entry: ocean trench ocean vent Noun
underwater fissure from which geothermally heated fluid is ejected.
Encyclopedic Entry: ocean vent ocean vent Noun
underwater fissure from which geothermally heated fluid is ejected.
Encyclopedic Entry: ocean vent organic Adjective
composed of living or once-living material.
living or once-living thing.
small piece of material.
measure of a substance's ability to have a another substance penetrate or diffuse it.
measure of a substance's acid or basic composition. Distilled water is neutral, a 7 on the pH scale. Acids are below 7, and bases are above.
drug or having to do with drugs and medications.
phase separation Noun
separation of a single solution into two distinct liquids.
process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.
microscopic organism that lives in the ocean and can convert light energy to chemical energy through photosynthesis.
to separate a solid from a solution.
animal that hunts other animals for food.
force pressed on an object by another object or condition, such as gravity.
to target, victimize, or devour.
before or ahead of.
organism on the food chain that can produce its own energy and nutrients. Also called an autotroph.
common type of mineral.
relationship between numbers or numerical values.
Reaction Zone Noun
phase in the ocean vent process where the vent fluid is closest to its source of heat.
Recharge Zone Noun
phase in the ocean vent process in which seawater seeps into fissures in the ocean floor.
research vessel Noun
ship or boat equipped to carry out scientific experiments or collect data.
residence time Noun
amount of time a water molecule spends in one place in the water cycle.
Ring of Fire Noun
horseshoe-shaped string of volcanoes and earthquake sites around edges of the Pacific Ocean.
Encyclopedic Entry: Plate Tectonics and the Ring of Fire river Noun
large stream of flowing fresh water.
Encyclopedic Entry: river ROV Noun
remotely operated vehicle.
overflow of fluid from a farm or industrial factory.
Encyclopedic Entry: runoff salinity Noun
mineral often used as a seasoning or preservative for food.
seafloor massive sulfide (SMS) deposit Noun
minerals that form from underwater hydrothermal vents.
sea level Noun
base level for measuring elevations. Sea level is determined by measurements taken over a 19-year cycle.
Encyclopedic Entry: sea level seamount Noun
solid material transported and deposited by water, ice, and wind.
Encyclopedic Entry: sediment seep Verb
to slowly flow through a border.
low-temperature ocean vent in which flocculent microbes are ejected.
low-temperature ocean vent in which flocculent microbes are ejected.
knowledgeable or complex.
to study, work, or take an interest in one area of a larger field of ideas.
to eject or discharge violently.
to increase quickly.
process of one tectonic plate melting, sliding, or falling beneath another.
small submarine used for research and exploration.
(SO42-) negatively charged ion (salt) of a sulfur-oxygen molecule.
(S2-) negatively charged ion of sulfur, or a chemical compound containing such an ion.
chemical element with the symbol S.
to assume or believe something.
tectonic activity Noun
movement of tectonic plates resulting in geologic activity such as volcanic eruptions and earthquakes.
tectonic plate Noun
massive slab of solid rock made up of Earth's lithosphere (crust and upper mantle). Also called lithospheric plate.
degree of hotness or coldness measured by a thermometer with a numerical scale.
Encyclopedic Entry: temperature terrestrial Adjective
having to do with the Earth or dry land.
to develop and be successful.
machinery that tows a complex set of instruments (the Conductivity-Temperature-Depth package) behind a research vessel, constantly raising and lowering the CTD to allow oceanographers to determine the shape of a hydrothermal plume.
trench rollback Noun
subduction process in which the leading edge of a subducting plate is "rolled back" toward the subducting plate. Also called hinge migration, hinge retreat, or hinge rollback.
one of a kind.
Upflow Zone Noun
phase in the ocean vent process in which super-heated vent fluid gushes upward toward the seafloor.
worth a considerable amount of money or esteem.
measurement of the rate and direction of change in the position of an object.
vent field Noun
collection of related hydrothermal vents.
vent fluid Noun
chemicals ejected by hydrothermal vents.
volcanic arc Noun
chain of volcanoes formed at a subduction zone.
an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.
Encyclopedic Entry: Plate Tectonics and Volcanic Activity water column Noun
area reaching from the sediment of a body of water to its surface.
well up Verb
to swell or build up.
white smoker Noun
type of ocean vent that ejects white mineral fluid into the surrounding water.