What is the value of the ocean twilight zone?

What does the twilight zone do for us?

Humans receive two key benefits from the twilight zone: the removal of heat-trapping carbon dioxide from the atmosphere, and the support of commercially important fisheries in the surface waters. Potential future benefits include the harvest of twilight zone fish to produce fish meal for aquaculture operations or fish oil for human health supplements. Society also receives indirect benefits from the twilight zone, such as the knowledge generated by marine science and the environmental stewardship that arises from greater awareness of the ocean.

How do we measure the value of an ecosystem?

Ecosystem services are the benefits humans realize from nature, either directly or indirectly. To assess the economic value of natural ecosystems, such as the twilight zone, economists estimate the demand for ecosystem services or calculate how much it would cost society to duplicate the services or to respond to their disappearance.


How does the twilight zone help remove carbon?

During their daily migration, the creatures of the twilight zone move heat-trapping carbon dioxide from surface waters to the deep ocean, where it can be stored for very long periods. The amount of carbon sequestered in the deep ocean is estimated to be between 2 and 6 billion metric tons (2.2 to 6.6 billion tons) annually. This is equivalent to 2 to 6 times the amount of carbon emitted by all the cars in the world each year.

What does this amount of carbon storage mean for Earth’s climate?

That much extra carbon in the atmosphere would be equivalent to carbon dioxide levels that are 200 parts per million (ppm) higher than today’s level of 400 ppm. The last time Earth’s atmospheric carbon dioxide was at that level 30 million years ago, average temperatures were 4 to 6°C (6 to 11°F) higher than today.

How much is this carbon storage worth?

There are several ways to calculate this. The first is by using the “social cost of carbon” (SCC), also known as a “carbon price,” which is an estimate of the present and future damages associated with the release of carbon dioxide from the burning of fossil fuels, like flooding or coastal erosion from sea-level rise, crop losses due to drought, or human illnesses from heat waves or disease. Using estimates of the SCC, the value of the twilight zone’s role in removing that amount of carbon may be worth between $300 to 900 billion annually. The value of carbon sequestration in the North Atlantic alone is worth $200 billion to $3.4 trillion over the next 80 years, when put in terms of the cost of preventing carbon from entering the atmosphere, and the cost of adapting to the global changes that would result from those emissions.


How does the twilight zone provide food for humans?

Humans are unlikely to eat anything caught from the twilight zone—the animals there are mostly small, bony fish and gelatinous organisms. However, some governments and corporations are planning to fish the twilight zone to provide fish meal for aquaculture operations to produce seafood for humans. Worldwide, aquaculture is expected to grow 37% by 2030 to help meet the protein demand of a growing human population and reduce pressure on fisheries that are increasingly over-fished.

What is the value of learning about the twilight zone?

Gaining knowledge about the twilight zone provides value by reducing the uncertainty surrounding climate change. Reducing uncertainty limits the range of potential future outcomes for which government agencies, businesses, non-governmental organizations, and individuals have to prepare. The value of scientific research that reduces this uncertainty may be on the order of tens of billions of dollars each year.

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How does the twilight zone support a healthy ocean?

Many animals in the twilight zone live in the ocean depths during daylight hours and migrate to the surface at night to feed. This moveable feast supports many species that live only at the surface. Some animals—like blue sharks, sperm whales, and swordfish—are able to dive deep into the ocean to feed in the twilight zone at any time. In addition, human appreciation of animals like whales, sharks, and seabirds, and for a healthy ocean, inspires greater environmental stewardship.

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Value Beyond View: Illuminating the human benefits of the ocean twilight zone