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Ocean Twilight Zone


Report reveals ‘unseen’ human benefits from ocean twilight zone

A new report from researchers at Woods Hole Oceanographic Institution (WHOI) reveals for the first time the unseen—and somewhat surprising—benefits that people receive from the ocean’s twilight zone. Also known as the “mesopelagic,” this is the ocean layer just beyond the sunlit surface.

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Value Beyond View: The Ocean Twilight Zone

How does the ocean twilight zone benefit life on Earth? The ocean twilight zone helps regulates our climate. Storing two to six billion tons of carbon annually. That’s up to six times the amount of carbon emitted from autos worldwide. Preventing an increase in temperature between 6-11°F. The ocean twilight zone supports a healthy ocean ecosystem. Containing 10 times more fish than the rest of the ocean. Providing food for many other animals in the ocean. The ocean twilight zone could also play an important role in feeding a growing population. We are working to better understand this realm in order to inform sustainable management decisions.

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Open Ocean Diving Observations

Watch and learn how blue and black water diving is conducted in the open ocean and what these divers see during the day and during the twilight zone migration at night.

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Tagging Sharks to Study the Twilight Zone

Former WHOI Joint Program graduate student and current University of Washington postdoc Camrin Braun and his team on the charter fishing vessel Machaca managed to tag two porbeagles, a relative of the goblin shark, about 30 miles east of Chatham, Mass. One was a female nearly seven feet long and weighing 270 pounds. A male came alongside the boat while the team was tagging her and, when they were finished, they quickly hooked the curious male, which measured 6.5 feet and weighed 230 pounds.

Both fish are now equipped with fin-mounted SPOT satellite tags, which will report their location each time they surface and can last up to five years. For the Ocean Twilight Zone team, the big predators are an important indicator of where mesopelagic animals are collecting deep below the surface. In short, the predator will go where the prey is.

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Paul Caiger hunts for things that glow in the Ocean Twilight Zone

Paul Caiger is a fish biologist, marine photographer and postdoctoral investigator at Woods Hole Oceanographic Institution (WHOI). From the ghoulish grimace of the viperfish, to the bejeweled beauty of the strawberry squid, Caiger’s marine portraits have helped shine a light in this dark but critical ocean zone.

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The Ocean Twilight Zone’s crucial carbon pump

Ken Buesseler

When CO₂ enters the ocean, where does this heat-trapping gas go? WHOI geochemist investigates how much carbon from the surface ocean is dispatched to the ocean twilight zone–the midlayer of the ocean–and on to the deep ocean.

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New Eyes in the Twilight Zone

Members of WHOI’s Ocean Twilight Zone team, particularly the lab led by marine biologist Annette Govindarajan, are pioneering the use of environmental DNA (eDNA) sampling and analysis to provide a more finely tuned picture of what lives deep beneath the surface of the ocean.

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Top of Mind with Julie Rose

BYU Radio

Associate Scientist Joel Llopiz describes the vast, virtually unexplored ecosystem lurking beneath the surface of the ocean known as the twilight zone. It is deep enough that it hasn’t really been affected by humans yet. But commercial fishing companies are eyeing it now, so scientists who study the Twilight Zone are urging the UN to establish some rules for it soon. (segment begins at 23:08)

Why we must protect the ocean’s ‘twilight zone’

Mother Nature Network

The twilight zone can be found 200 to 1,000 meters (about 650 to 3,300 feet) below the ocean surface, at the point where the sun’s rays can no longer reach, according to the Woods Hole Oceanographic Institute (WHOI) in Massachusetts. Because it’s so deep and there’s no sunlight, it’s cold and dark.

Minion robots in the Ocean Twilight Zone

Phytoplankton use sunlight and carbon dioxide to grow, forming the base of the ocean food web. Phytoplankton are eaten by zooplankton, which are eaten by other animals. Dead zooplankton and other particles become marine snow drifting in the ocean, but how much marine snow sinks below the sun-lit ocean surface? Scientists are developing a new device
that will follow marine snow into the ocean’s twilight zone.

The MINION is a small (2 Liters) inexpensive instrument. It is equipped with… cameras, seawater sensors, acoustic recorder, ballast weight. Once deployed, MINION will sink to the twilight zone and drift with currents.

Cameras on the side record the rate and quantity of particles falling through the ocean. Falling particles also accumulate on a clear glass panel. A camera on top will record the particle type and accumulation rate.

Similar images have revealed the twilight zone is a perpetual snowstorm, of organic debris. Particles such as this fecal pellet from a jellyfish-like salp are extremely carbon-rich. Pellets like this will sink quickly to deeper waters, or even become buried in the seafloor. Any marine snow that reaches the deep ocean means less carbon in the atmosphere.

The MINION is designed to listen for underwater sound sources. This will determine their location as they drift.

After a MINION has finished its mission, it will release weight and float to the surface. At the surface, it sends a homing signal so it can be recovered. The next generation of MINION will send compressed data-sets via satellite. Allowing them to be deployed by the dozens. Data from MINIONS will help scientists learn more about the ocean’s role in Earth’s climate system.

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Creatures of the Ocean Twilight Zone

The ocean twilight zone is home to innumerable mysterious creatures. Most of them are very small. Some glow in the dark. Others are just plain bizarre. They all play an important role in maintaining the health of this complex ecosystem. An ecosystem we are only beginning to understand.

This was part of a mission in spring of 2019 where several members of the OTZ Project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise. The Ocean Twilight Zone is supported by the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

Video by Erik Olsen

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What’s it like in a submersible?

It is hard to describe what it’s like to physically travel down to the twilight zone. Both Heidi Sosik, senior scientist at Woods Hole Oceanographic Institution and Ocean Twilight Zone (OTZ) project lead and Joel Llopiz, Associate Scientist, and OTZ lead of the life histories and behavior theme went down in a submersible for the first time to experience the twilight zone. They were able to able to observe beautiful jellies and small fishes like bristlemouths, hatchetfish, and lanternfish, all in their natural habitat.

This was part of a mission in spring of 2019 where several members of the OTZ Project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise. The Ocean Twilight Zone is supported the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

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What is the story behind Mesobot?

Mesobot is designed to let scientists observe the twilight zone by autonomously tracking individual animals for hours or even days without disturbing the environment or disrupting their behavior, making it possible to follow individual animals as they take part in the great migration from the twilight zone to the surface and back each day. Mesobot is also equipped with samplers that will allow it to capture traces of environmental DNA (eDNA) from seawater while on a dive. The engineering team held their first successful at-sea test in June of 2019.

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Discovering the Ocean Twilight Zone with Joel Llopiz

Most life forms in the twilight zone are tiny—a few inches or less—but even the smallest twilight zone inhabitants are powerful through sheer number. Joel Llopiz, Associate Scientist at the Woods Hole Oceanographic Institution, is part of the Ocean Twilight Zone (OTZ) project. The project is embarking on a bold new journey to explore one of our planet’s hidden frontiers—the ocean twilight zone, a vast, globe-spanning, and dimly lit region between about 200 and 1,000 meters beneath the ocean’s surface. Understanding of the twilight zone is currently limited by its enormous size and lack of easy access.

Several members of the OTZ project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas in spring of 2019. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. Going to different areas is critical to help us understand how abundance and types of organisms change geographically. Even from onboard observations, it was clear that this area has far fewer organisms than off the more nutrient-rich waters of New England. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise.

The Ocean Twilight Zone is supported the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

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Entering the Ocean Twilight Zone with Heidi Sosik

It is hard to describe what it’s like to physically travel down to the twilight zone. In addition to extraordinary bioluminescence, Heidi Sosik, senior scientist at Woods Hole Oceanographic Institution and Ocean Twilight Zone (OTZ) project lead, was able to observe beautiful jellies and small fishes like bristlemouths, hatchet fish, and lanternfish, all in their natural habitat.

Several members of the OTZ Project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas in spring of 2019. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. Scientists conducted net tows to collect animals at specific depths within the twilight zone and went down in a manned submersible to observe life there. They also collected water samples for environmental DNA analysis, a kind of forensic tool that allows scientists to sleuth out organisms the scientists weren’t able to physically catch. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise.

The Ocean Twilight Zone is supported the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

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Meet an Ocean Twilight Zone photographer

Fish ecologist, Paul Caiger explains how he brings together his passion for the Ocean Twilight Zone and photography to shed light on one of the least known regions on the planet. This was part of a mission in spring of 2019 where several members of the OTZ Project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise. The Ocean Twilight Zone is supported by the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

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Researching the Twilight Zone

Meet WHOI technician, Helena McMonagle, and learn how research is conducted in the twilight zone using MOCNESS. This was part of a mission in spring of 2019 where several members of the OTZ Project team conducted an expedition aboard OceanX’s research vessel, the M/V Alucia, out of the Bahamas. The main goal of the expedition was to examine how the OTZ project site off the coast of New England differs from this distant –yet connected– region of the twilight zone. The team worked closely with OceanX to share their journey through video diaries and photographs of the extraordinary creatures brought on board throughout the cruise. The Ocean Twilight Zone is supported by the Audacious Project, a collaborative endeavor, housed at TED, to surface and fund ideas with the potential to create change at thrilling scale.

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Mesobot: Following life in the Twilight Zone

Mesobot is a brand new underwater vehicle designed to reveal what lives in the ocean’s twilight zone. Mesobot can follow animals as they move through the darkness and as they migrate from the depths to the surface and back. The twilight zone is vast and remote, but is threatened by unregulated fishing and climate change. We need Mesobot’s insights to understand and protect the twilight zone before humans change it forever.

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