Life that exists in this zone must be able to function in cold temperatures and withstand extreme hydrostatic pressure. Despite the extreme environment, organisms here must find food and mates and avoid predators, just as they do in any ecosystem, and they have special adaptations that allow them to do so. Understanding how the biological carbon pump works to export carbon to the deep sea can help researchers improve models of the ocean’s role in climate. The ocean’s ability to absorb carbon dioxide varies over time and space and is predicted to decline over the rest of this century.

Tracking carbon from the ocean surface to the twilight zone

A more detailed understanding of the pump’s ability to remove carbon will improve climate models and the ability to forecast the potential impacts of global heating. Despite how far offshore and difficult to reach the twilight zone is, recent technology innovations have begun to make it a more attractive location for commercial fisheries. We need to understand the impact such activities would have not only on the ecosystem, but also on the biological carbon pump and its ability to help us fight the climate crisis. As the level of carbon dioxide in Earth’s atmosphere rises, the ocean’s pH—a measure of alkalinity and acidity—has fallen, meaning that it has become less alkaline and more acidic.

Are warming Alaskan Arctic waters a new toxic algal hotspot?

Scientists now know these bacteria are responsible for half of the ocean’s primary productivity and are the most abundant organisms in the sea. Because they need light, phytoplankton live near the surface, where enough sunlight can penetrate to power photosynthesis. Scientists are particularly interested in the various ways animals here Bonisa casino bioluminesce and how their visual systems are adapted to detect this natural glow. Because they may play an extensive role in the carbon cycle and eventual deep-sea carbon storage, understanding their activity is an essential step toward addressing climate change. These vehicles are piloted remotely from ships to which they are tethered and collect water samples, organisms, video, and still photos of life in the depths. In addition to the lack of light, the midnight zone is characterized by a steady temperature of around 4° Celsius (39° Fahrenheit).
Small marine animals called zooplankton feed on phytoplankton and are, in turn, eaten by larger marine organisms. The ocean’s so-called biological carbon pump removes carbon from the atmosphere and stores it deep in the ocean on timescales that are important to the lifespan of humans. The solubility carbon pump, which stores much larger amounts of carbon, operates on timescales in the thousands of years and is a much slower mixing process. Through photosynthesis these organisms transform inorganic carbon in the atmosphere and in seawater into organic compounds, making them an essential part of Earth’s carbon cycle.

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• Too small to be caught in any net, these organisms were unknown until the 1970s, when improved technology made them visible.

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• In addition to the lack of light, the midnight zone is characterized by a steady temperature of around 4° Celsius (39° Fahrenheit).

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• Larger phytoplankton are single-celled algae also known as protists—tiny organisms that also contain chloroplasts.

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• The resulting bathypelagic, or midnight, zone extends to about 4,000 meters (about 13,100 feet), which reaches the ocean floor in many places.
• Jellyfish are among the simplest animals on Earth and are considered plankton, but some individuals have been measured at 130 feet long, longer than a blue whale.
• Another major category is the gelatinous zooplankton or jellies, unrelated groups that all have soft, transparent bodies and spend much of their life drifting in the water column.

The ocean’s ‘biological pump’ captures more carbon than expected

They take up, transform, and recycle elements needed by other organisms, and help cycle elements between species in the ocean. Many creatures called zooplankton are also tiny protists, but the category simultaneously includes animals on the other end of the size scale. Jellyfish are among the simplest animals on Earth and are considered plankton, but some individuals have been measured at 130 feet long, longer than a blue whale. Larger phytoplankton are single-celled algae also known as protists—tiny organisms that also contain chloroplasts. Many photosynthetic protists are capable of movement and some also hunt and eat other single-celled organisms. Little is known about the animals that inhabit these waters, and even less is known about microbial life in this zone.

A Better Understanding of Gas Exchange Between the Atmosphere and Ocean Can Improve Global Climate Models

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• Small marine animals called zooplankton feed on phytoplankton and are, in turn, eaten by larger marine organisms.

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• These vehicles are piloted remotely from ships to which they are tethered and collect water samples, organisms, video, and still photos of life in the depths.
• Despite how far offshore and difficult to reach the twilight zone is, recent technology innovations have begun to make it a more attractive location for commercial fisheries.

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• Understanding how the biological carbon pump works to export carbon to the deep sea can help researchers improve models of the ocean’s role in climate.

|}

• Zooplankton fill a crucial link between phytoplankton (“the grass of the sea”) and larger, open-ocean animals.

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• In turn, the billions of cells produced might absorb enough heat-trapping carbon dioxide to cool the Earth’s warming atmosphere.

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Scientists have found that some zooplankton from the sunlit zone migrate down into the midnight zone during the day to avoid predators. The midnight zone is also where many larvae spend time developing before they migrate to other regions of the ocean as adults. The smallest zooplankton are single-celled protozoans, also called microzooplankton, which eat the smallest phytoplankton cells in the ocean. Dense blooms of some organisms can deplete oxygen in coastal waters, causing fish and shellfish to suffocate. These tiny cells, some only a micron across, are invisible but present in numbers of hundreds of thousands of cells per tablespoon of ocean water. Too small to be caught in any net, these organisms were unknown until the 1970s, when improved technology made them visible.
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• Scientists are particularly interested in the various ways animals here bioluminesce and how their visual systems are adapted to detect this natural glow.

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• By feeding at the surface before returning to deeper waters, these animals actively carry carbon deeper into the water column.

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• An account of the tools that have been employed to collect zooplankton has been recently prepared by Wiebe and Benfield (2000), and provides a description of standard sampling methods.
• Because they may play an extensive role in the carbon cycle and eventual deep-sea carbon storage, understanding their activity is an essential step toward addressing climate change.
• The biological carbon pump plays a huge role in the ocean’s ability to remove carbon dioxide from the atmosphere.

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• Through photosynthesis these organisms transform inorganic carbon in the atmosphere and in seawater into organic compounds, making them an essential part of Earth’s carbon cycle.

|}

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Researching phytoplankton 2000 miles from shore aboard the R/V Atlantis

Zooplankton fill a crucial link between phytoplankton (“the grass of the sea”) and larger, open-ocean animals. An account of the tools that have been employed to collect zooplankton has been recently prepared by Wiebe and Benfield (2000), and provides a description of standard sampling methods. In turn, the billions of cells produced might absorb enough heat-trapping carbon dioxide to cool the Earth’s warming atmosphere.
Every evening in the ocean, animals that spend their days in the deep, dark waters of the ocean’s twilight zone swim to the surface to feed. Rising in the dark after sunset, these animals feast on phytoplankton, zooplankton, and other surface-dwelling organisms throughout the night, then return to depth as light returns at dawn. By feeding at the surface before returning to deeper waters, these animals actively carry carbon deeper into the water column. When sunlight hits the ocean’s surface waters, it stimulates tiny marine plants called phytoplankton to photosynthesize. This process removes carbon dioxide dissolved in the water as phytoplankton incorporate the carbon as they grow. As carbon dioxide levels in surface waters decrease, water is then able to absorb more carbon dioxide from the atmosphere.
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Jellyfish-Like Creatures May Play Major Role in Fate of Carbon Dioxide in the Ocean

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Both salps and krill also live in the Southern Ocean near Antarctica, and both feed directly on the great abundance of phytoplankton there. Scientists think that the extent of sea ice and the temperature of the ocean each year may influence the balance between salp and krill populations. Unfortunately, the gelatinous salps have much lower nutritional content and therefore are not good food for those higher-level animals.
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Yawkey Foundation and WHOI present Summer Speaker Series, “Dispatches from an Ocean Planet”

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Another major category is the gelatinous zooplankton or jellies, unrelated groups that all have soft, transparent bodies and spend much of their life drifting in the water column.