![]() ![]() Many fish have a swim bladder, a gas-filled organ that helps them maintain buoyancy. Bringing fish to the surface quickly exposes them to lower pressures, which causes the volume of the gases inside their swim bladder to expand. Pressure is higher the deeper you go in the ocean, and fish living in the twilight zone are specially adapted to live at high pressures. They knew that if they tried to bring fish up from that depth, the fish could die. However, the researchers ran into a problem. They also wanted to display the fish in the aquarium for the public to see. Courtesy of California Academy of Sciences.Īs part of their research, Shepherd and Rocha wanted to collect live fish of newly discovered species in order to study their behavior. School of fish in ocean's twilight light zone. ![]() “You know, one of the great questions that we still have is what are the connections between the shallow reefs and these twilight zone reefs? And that’s really why we are studying it, and that’s really why we continue to go and look there,” explains Shepherd. The scientists are studying the twilight zone to learn about the biodiversity of this region and the greater role it plays in the health of the ocean ecosystem. So, these are all new records, either new records of depth extensions or range extensions or new species,” says Rocha, curator of ichthyology at the Academy. The other half we didn’t know that they went that deep. “Everywhere we go about half of the fish are not known. “More people have been to the surface of the moon than have been to these reefs,” says Shepherd, director of the Academy’s Steinhart Aquarium. Courtesy of California Academy of Sciences. Bart Shepherd and Luiz Rocha, of the California Academy of Sciences, are among a group of scientists lucky enough to be able to dive and explore these depths.ĭivers in the twilight zone in the Philippines. Diving to this region requires specialized training and gear, and it takes hours to safely return to the surface after each dive. Scientists have many unanswered questions about the twilight zone, in part because it is so hard to reach. Some parts of the twilight zone (or mesophotic zone, as it’s known in scientific circles) are vast ocean space, but others are home to incredible coral reefs. Courtesy of California Academy of Sciences.ĭeep beneath the ocean’s surface lies a mysterious region known as the “twilight zone.” At 50 to 150 meters (200 to 500 feet) deep, this part of the ocean receives very little light, mimicking twilight - the time of day just after sunset. The paper, published in the journal Nature Communications, is entitled: “What the geological past can tell us about the future of the ocean’s twilight zone.Diver exploring the ocean's twilight zone. The study was funded by the Natural Environment Research Council and includes researchers from the universities of Exeter, Liverpool, California Riverside, Bremen, Cardiff, and University College London. At the current rate, the “medium” scenario would be reached 50 years from now, and the “high” in just over a century. For context, the Global Carbon Budget (led by the University of Exeter) estimated total global carbon dioxide emissions of 40.6 billion tonnes in 2022 alone.Įmissions have been close to 40 billion tonnes every year from 2010-22, so most of the carbon dioxide (about 500 billion tonnes) for the study’s “low” scenario has already been emitted. “Low” is 625 billion tonnes, “medium” is 2,500 billion tonnes, and “high” is 5,000 billion tonnes. ![]() The study’s three emissions scenarios are based on total carbon dioxide emissions after 2010. The study shows that in warmer seas of the past, this organic matter was degraded much faster by bacteria – meaning less food reached the twilight zone. In a high-emissions future, life in the twilight zone could be severely depleted within 150 years, with no recovery for thousands of years, as animals mainly feed on particles of organic matter that have sunk down from the ocean surface. “We still know relatively little about the ocean twilight zone, but using evidence from the past we can understand what may happen in the future,” said Dr Katherine Crichton of Exeter University, the lead author of the study. The ocean’s twilight zone (200m to 1,000m deep) receives little light but is home to a wide variety of organisms and billions of tonnes of organic matter, but a new study warns that climate change could cause a 20-40 per cent reduction in twilight zone life by the end of the century. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |