Mid Ocean Ridges, Volcanoes, and the Arctic

Summary

This script provides an insightful look into the fascinating world of ocean ridges and hydrothermal vents. It explores the formation of the longest chain of volcanoes on our planet, spanning 40,000 miles, marking the boundary between tectonic plates. As these plates move apart, magma ascends and erupts, forming volcanoes on the seafloor, essentially repaving the surface of our planet. The script then delves into the remarkable thermal vent systems, which are like underwater Yellowstones, where seawater chemically reacts with rocks, creating hot, acidic fluids that concentrate metals. The Gakkel Ridge, with its unique geology and potential for undiscovered life forms, is highlighted as a fascinating analogue for early Earth's hydrothermal activity.

Takeaways

• 🌋 Mid-ocean ridges are composed of the longest chain of volcanoes on Earth, stretching about 40,000 miles (60,000 km) around the globe.
• 🧩 Mid-ocean ridges mark the boundary between two tectonic plates, which are moving apart, allowing molten rock to ascend and erupt on the seafloor, forming volcanoes.
• 🌡️ Hydrothermal vents are like underwater Yellowstone National Park, where seawater percolates into the ground, gets heated by magma, and rises back up, forming a convection system.
• 🔄 As seawater descends into the rocks, it chemically reacts with them, becoming acidic and removing metals, which then precipitate out as sulfides when the fluid mixes with oxygenated seawater.
• 🌍 The mid-ocean ridges are a way of concentrating metals into deposits by extracting them from the ocean crust.
• 🔬 The Gakkel Ridge is a slow-spreading ridge with no volcanic activity, exposing rocks from the mantle layer, which have different chemistry and produce different elements and gases.
• 🦠 The different chemistry along the Gakkel Ridge may lead to the discovery of unique organisms that have never been seen before.
• 🌍 The Gakkel Ridge's exposed mantle rocks may provide insights into the early types of volcanic activity on Earth.
• 🤞 The hope is to find a wide range of different types of hydrothermal systems, both high and low temperature, to facilitate comparisons and research.
• 😨 The fear is losing autonomous underwater vehicles or not finding any vents, which would be a major disappointment.

Q & A

What are mid-ocean ridges?

Mid-ocean ridges are the longest chain of volcanoes on our planet, stretching about 40,000 miles or 60,000 kilometers around the globe. They mark the boundary between two tectonic plates, which are moving apart, allowing magma or molten rock to ascend and erupt on the seafloor, forming volcanoes.

How are hydrothermal vents formed?

Hydrothermal vents are formed through a convection system similar to a saucepan of water on the stove. Seawater percolates into the rocks, gets heated up by magma or hot spots, becomes buoyant, and discharges back to the surface. As the fluid goes deeper, it chemically reacts with the rocks, removing metals and becoming acidic and oxygen-depleted.

What are hydrothermal vents made of?

Hydrothermal vents are made of minerals that have been removed from the ocean crust. When the heated fluid mixes with seawater, becomes oxygenated, and cools down, the elements in the fluid precipitate out as sulfides, such as iron, copper, and zinc sulfides.

What is the Gakkel Ridge?

The Gakkel Ridge is one of the slowest spreading ridges along the mid-ocean ridge system. It is not characterized by volcanic activity, but instead, it exposes rocks from the mantle layer, which have a different chemistry and produce different gases and elements compared to volcanic areas.

Why is the Gakkel Ridge interesting?

The Gakkel Ridge is interesting because the exposed mantle rocks have a chemistry similar to the early volcanic activity on Earth, making it a potential analogue for studying hydrothermal activity on early Earth. It may also host different types of organisms due to the different chemical environment.

What are the hopes and fears of the researchers?

The greatest hope of the researchers is to find a range of different types of hydrothermal systems, both high and low temperature, on volcanic areas and areas with exposed mantle rock. This would provide a great comparison. The greatest fear is either losing autonomous underwater vehicles during the high-risk operation or not finding any vents at all, which would be a major disappointment.

What is the significance of studying hydrothermal vents?

Studying hydrothermal vents is important because they are a way of concentrating metals into deposits and repaving the surface of our planet. They also provide insight into the early volcanic activity and hydrothermal systems on Earth.

What is the role of seawater in hydrothermal vent systems?

Seawater plays a crucial role in hydrothermal vent systems. It percolates into the rocks, gets heated up by magma or hot spots, and chemically reacts with the rocks as it goes deeper, removing metals and changing its composition. The heated fluid then discharges back to the surface, forming hydrothermal vents.

What are tectonic plates?

Tectonic plates are portions of the Earth's crust that can be thought of as jigsaw puzzle pieces that are moving relative to each other. Mid-ocean ridges mark the boundary between two tectonic plates that are moving apart, allowing magma to ascend and create volcanoes.

What is the role of autonomous underwater vehicles in studying hydrothermal vents?

Autonomous underwater vehicles (AUVs) play a crucial role in studying hydrothermal vents, as they allow researchers to explore and gather data from these deep-sea environments. However, their use in high-risk operations, such as exploring hydrothermal vents, poses a risk of losing the AUVs.

Outlines

00:00

🌋 Mid-Ocean Ridges: Earth's Underwater Volcanic Networks

The first paragraph describes mid-ocean ridges as the planet's longest chain of volcanoes, extending approximately 40,000 miles or 60,000 kilometers globally, akin to the seams on a baseball. These ridges delineate the boundaries between tectonic plates, which are segments of Earth's crust that move relative to each other. At these ridges, tectonic plates diverge, allowing magma to ascend and form underwater volcanoes, effectively repaving Earth's surface. The paragraph further explains high-thermal vent systems, likening them to Yellowstone's geysers, where seawater, heated by underlying magma, rises to the ocean floor, undergoing chemical reactions with rocks. This process extracts metals from rocks, resulting in the precipitation of sulfides like iron, copper, and zinc when the fluid re-emerges and cools, forming mineral deposits. The GAC Aldridge, a notably slow-spreading ridge, exposes mantle rocks instead of volcanic ones, leading to unique chemical interactions and potentially novel life forms due to the differing available energy sources. This environment may offer insights into early Earth's volcanic activity and hydrothermal systems.

05:01

🔍 Exploration Hopes and Fears: A Deep-Sea Journey

The second paragraph reflects on the excitement and concerns associated with exploring the mid-ocean ridges using autonomous underwater vehicles. While the speaker, not a biologist, expresses enthusiasm for the fascinating biology encountered in these extreme environments, there is an underlying fear of losing these valuable exploration tools or not finding any hydrothermal vents, which would be a significant disappointment. This exploration, funded by the National Science Foundation and produced by the Woods Hole Oceanographic Institution, aims to uncover a range of hydrothermal systems and potentially undiscovered life forms, enriching our understanding of Earth's underwater ecosystems and their historical significance.

Keywords

💡Ocean Ridges

Ocean ridges are the longest chain of volcanoes on the planet, stretching about 40,000 miles or 60,000 kilometers around the globe. These ridges mark the boundary between two tectonic plates, which are portions of the Earth's crust that move relative to each other. Along the mid-ocean ridges, the tectonic plates are moving apart, allowing magma or molten rock to ascend between them and erupt on the seafloor, forming volcanoes. This process essentially repaves the surface of our planet.

💡Tectonic Plates

Tectonic plates are portions of the Earth's crust that can be thought of as jigsaw puzzle pieces that move relative to each other. Along the mid-ocean ridges, these plates are moving apart, creating space for magma to rise and erupt, forming volcanoes. The movement and interactions of these plates are responsible for many geological processes and features on Earth.

💡Hydrothermal Vents

Hydrothermal vents are highly thermal vent systems that occur on the seafloor, similar to geysers found in places like Yellowstone National Park. They are formed when seawater percolates down into the Earth's crust, gets heated by magma or hot rocks, and then buoyantly discharges back up to the surface. As the seawater interacts with rocks at different depths and temperatures, it undergoes chemical reactions that result in the fluid becoming acidic, losing oxygen, and picking up dissolved metals. When this fluid mixes with seawater and cools, minerals like iron, copper, and zinc sulfides precipitate out, forming the vent structures.

💡Gakkel Ridge

The Gakkel Ridge is a slow-spreading mid-ocean ridge with little volcanic activity. Instead of a volcanic layer of rocks on the top, the rocks that form the Earth's mantle (the layer below the crust) become exposed along this ridge. These mantle rocks have a different chemical composition, leading to different chemical reactions with seawater and the production of different elements and gases. This unique geology may support different types of organisms that use these alternative energy sources, potentially revealing new forms of life.

💡Early Earth Analogue

The exposed mantle rocks along the Gakkel Ridge have a chemistry similar to the early volcanic activity on Earth. As a result, these areas may serve as the best analogues for understanding hydrothermal activity on early Earth, providing insights into the conditions and processes that shaped our planet's early environment.

💡Autonomous Underwater Vehicles (AUVs)

Autonomous Underwater Vehicles (AUVs) are robotic vehicles used for exploration and research in the deep ocean. They allow scientists to study and gather data from extreme environments like hydrothermal vents without having to physically be there. However, the use of AUVs in these high-risk operations carries the risk of losing them, which is a major concern for the researchers.

💡Volcanic Activity

Volcanic activity refers to the eruption of magma or molten rock from within the Earth's crust. Along mid-ocean ridges, this activity creates new seafloor as the tectonic plates move apart, allowing magma to rise and form volcanoes. The heat and chemistry associated with volcanic activity drive the hydrothermal vent systems that support unique ecosystems on the seafloor.

💡Hydrothermal Systems

Hydrothermal systems are the processes and structures that facilitate the circulation of seawater through the Earth's crust, where it is heated and chemically altered before discharging back to the surface. These systems occur at both high and low temperatures and can take different forms depending on the geology and chemistry of the area. Studying diverse hydrothermal systems can provide valuable insights into the range of environments and life that may have existed on early Earth.

💡Mantle Rocks

Mantle rocks are rocks that originate from the Earth's mantle, the layer below the crust. Along the Gakkel Ridge, these rocks become exposed due to the slow spreading of the tectonic plates, allowing seawater to interact directly with them. The unique chemical composition of these rocks leads to different chemical reactions with seawater, potentially supporting different types of organisms and ecosystems compared to those found around volcanic ridges.

💡Ecosystems

Ecosystems are the complex communities of living organisms and their physical environments, including all the interactions and relationships that exist within them. The unique conditions and energy sources found at hydrothermal vents support diverse ecosystems with fascinating organisms that have adapted to these extreme environments. Studying these ecosystems can provide insights into the potential for life in different geological settings, both on Earth and beyond.

Highlights

Mid-ocean ridges are the longest chain of volcanoes, stretching about 40,000 miles around the globe.

These ridges mark the boundary between tectonic plates, which move apart allowing magma to form new sea floor volcanoes.

Mid-ocean ridges play a crucial role in repaving the Earth's surface.

Hydrothermal vent systems are likened to an underwater Yellowstone, where sea water interacts with magma to create geysers.

These systems act as natural convection systems, where heated water rises and cold water sinks, facilitating chemical reactions.

As water chemically reacts with rocks, it becomes acidic, oxygen-depleted, and rich in metals.

The interaction between seawater and the sea floor rocks results in fluid rich in iron, copper, and zinc sulfide.

Hydrothermal vents are crucial for concentrating metals from the ocean crust into deposits.

The Gakkel Ridge represents a slow-spreading ridge with unique geological and biological features due to the lack of a volcanic layer.

Mantle-exposed rocks at slow-spreading ridges like Gakkel Ridge offer insights into different chemical reactions and potentially unique life forms.

These areas might provide the best analogues for studying hydrothermal activity on early Earth.

Exploration hopes include discovering a range of hydrothermal systems and unique biology in both volcanic areas and those with exposed mantle rock.

Despite not being a biologist, the speaker expresses fascination with the diverse marine life found near hydrothermal vents.

Concerns include the high-risk nature of using autonomous underwater vehicles for exploration and the possibility of not finding any vents.

The podcast highlights the significance of ongoing research funded by the National Science Foundation at the Woods Hole Oceanographic Institution.

Transcripts

you

in ocean ridges are composed of the

longest chain of volcanoes that we have

on our planet it's a chain of volcanoes

that stretches about 40,000 miles or

60,000 kilometers around the globe a

little bit like scenes on a baseball and

the mid-ocean ridges mark a boundary

between two what are called tectonic

plates which are portions of the crust

that you can think of as like jigsaw

puzzle pieces that in fact are moving

relative to each other and along the

mid-ocean ridges the these tectonic

plates are moving apart and magma or

molten rock ascends between them and

erupts on the sea floor to form

volcanoes so it's essentially the place

where we're repaving the surface of our

planet so a highly thermal vent system

is nothing more than a Yellowstone but

at the bottom of the ocean at

Yellowstone National Park we have

geysers and those are formed because

groundwater or rain water percolates

into the ground and then gets heated up

because there's a hot spot oritse molten

magma beneath Yellowstone and that fluid

then gets heated up becomes very buoyant

and discharges back up to the ground in

the oceans it's the same thing it's

essentially a convection system just

like you have a saucepan of water on the

stove as you heat that water the hot

water rises to the surface and hallward

water

the surface goes down to the bottom of

the pan gets heated up in the sea floor

system what happens is as that fluid

goes down into the rocks it chemically

reacts with those rocks as you go deeper

down temperatures get higher and

different reactions go on so we've gone

from a cold alkaline oxygenated seawater

to a fluid that's very acidic has no

oxygen and as it continues down as it

gets deeper and deeper it starts to

remove the metals from the rocks so the

fluid that comes back up to the surface

has a lot of these metals in the

solution once it mixes with sea water

becomes oxygenated temperature decreases

those elements precipitate out as

sulfides iron copper and zinc sulfide

the vents actually are made of minerals

that have been removed from the ocean

crust so it's a way of concentrating

metals into a small or large deposit the

GAC Aldrich is one of the slowest

spreading ridges along the mid-ocean

ridge system and as that ridge is

spreading there isn't any volcanic

activity which means there isn't a

volcanic layer of rocks on the top

instead what you have is rocks that feel

the layer of the earth called the mantle

which is the layer right below the crust

become exposed along that Ridge now

those rocks have a very different

chemistry and hence the chemical

reactions that go on between seawater

and those rocks are different and they

produce different elements they produce

different gases

and hence the the the material or the

gases that the organisms use as their

energy source is different so

consequently we might have for example

different types of organisms along those

areas perhaps some that we've never seen

before the other reason that this is

interesting is because those types of

rocks are very similar in chemistry to

what we believe was the early type of

volcanic activity on earth and

consequently those areas may be our best

analogues for hydrothermal activity on

early Earth my greatest hope is that we

find a whole range of different types of

hydrothermal systems both high and low

temperature so actually on the volcanic

areas and some on the areas with exposed

mantle rock because that would provide

us with a great comparison although I'm

not a biologist I always love to see the

biology because the animals are always

absolutely fascinating my greatest fear

I suppose my greatest fear is either we

lose our autonomous underwater vehicles

since this is something that is a pretty

high-risk operation or we don't find any

vents and that would be that would

certainly be a major disappointment

this podcast was produced by the Woods

Hole Oceanographic Institution with

funding from the National Science

Foundation for more information visit us

on the web at polar discovery dot whi

edu