What's New Archive
PMEL scientists have analyzed the recordings collected from a successful deployment of a deep-ocean hydrophone mooring in Challenger Deep in the Mariana Trench. The Challenger Deep is the deepest known location in Earth's oceans, about 36,000 feet (10,971 meters) beneath the ocean surface. It is located in the Pacific Ocean near Guam. The recordings captured a baleen whale’s call, a magnitude 5.0 earthquake, an overhead typhoon and ship traffic noise. PMEL, in collaboration with the crew of the Coast Guard Cutter Sequoia and with funding from NOAA’s Office of Ocean Exploration and Research, deployed the hydrophone on January 17, 2015 for 22 days. The purpose of the project was to establish a baseline for noise in the deepest part of the Pacific Ocean.
This map shows the timeframe (year) in which the anthropogenic trend becomes distinguishable from internal climate variability. The darker red indicates earlier emergence of the trend while the orange/white areas show emergence later on. The blue stars indicate current ocean carbon sampling locations.
The ocean absorbs a significant fraction, about 40%, of carbon released by fossil fuel burning, thereby reducing climate warming. However, natural climate variability makes it difficult to directly observe trends in the amount of anthropogenic carbon the ocean is taking up with time. PMEL scientist and collaborators utilized a modeling approach to separate out the ocean carbon trend due to man-made carbon emissions from this variability. This separation illustrates the timeframe over which we may expect to observe human driven change in carbon uptake in different ocean regions. The results show that these trends are largely not detectable at present, but may begin to emerge in certain regions between 2020-2050. The Southern Ocean and Atlantic region are projected to show this uptake first, while the latest emergence occurs in the Pacific and Indian subtropical regions.
NOAA scientists and collaborators have just published a review article in Annual Review of Marine Science that summarizes our GO-SHIP repeat hydrography efforts conducted since the early 1990’s across the global oceans. The article found that the ocean is taking up a large fraction of the carbon dioxide and most of the excess heat caused by fossil-fuel burning and land use changes. Roughly 27% of the carbon dioxide released into the atmosphere by human activities is stored in the ocean, which in turn lowers the pH in the upper ocean. The ocean is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the deep ocean beneath 2,000 m, dominated by Southern Ocean deep-ocean warming. The global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization.
PMEL’s Argo float group relies upon and is very grateful for assistance from scientists and crew in deploying PMEL Argo floats on a variety of ships in oceans around the globe. PMEL Argo recently sent six floats to the R/V Falkor of the Schimdt Ocean Institute for deployment on a science cruise studying oxygen minimum zones across in the tropical Pacific. Float deployments during this cruise helped to fill a coverage gap in the Argo array that had opened up in this crucial region during a significant El Niño. As an unexpected bonus, artist-at-sea Michelle Schwengel-Regala was yarn-bombing on the Falkor during this cruise. Here are pictures of two PMEL Argo floats on the Falkor nestled in her dazzling knitted float-cozies! The yarn was removed and repurposed prior to deployment of the floats, all of which are now reporting vital ocean temperature and salinity data back from the tropical Pacific, monitoring the evolving El Niño.
NOAA scientists and collaborators from Lawrence Livermore National Laboratory have just published a paper in Nature Climate Change that shows that approximately half of the global ocean heat content increase since 1865 has occurred over the past two decades. This study included ocean temperature measurements that went as far back as the 19th century and compared them with a suite of climate models to analyze changes over time. While the majority of measurements are from the upper ocean, study results show the deep ocean is storing an increasing fraction of the Earth's net heat uptake as a result of global warming with time. To get more temperature measurements of the deep ocean, PMEL is working with university partners to develop and deploy regional pilot arrays of Deep Argo floats, which can measure to depth of 6,000 meters.
PMEL Scientists have identified four new hydrothermal vent sites along the Mariana Back-Arc. The region was systematically surveyed over the course of a 28 day cruise aboard the R/V Falkor that was just completed. In addition to the new sites, the scientists identified that one site had evidence of a recently erupted lava flow. The lava flow is the deepest historical eruption yet discovered (at 4100-4450 meters deep) and the first to be found along a slow-spreading ridge.
Read the press release and the cruise blog, both from the Schmidt Ocean Institute which supported the cruise by providing ship time and equipment. The mission was also supported by NOAA Ocean and Research Program and NOAA’s Pacific Island Regional Office.
In 2015, Arctic sea ice reached a maximum extent on 25 February, 15 days earlier than average and the lowest value on record (1979-present). Minimum ice extent in September was the 4th lowest on record. Sea ice continues to be younger and thinner than it was 30 years ago. Changes in sea ice alone are having profound effects on the marine ecosystem (fishes, walruses, primary production) and sea surface temperatures.
Melting occurred over more than 50% of the Greenland Ice Sheet for the first time since the exceptional melting of 2012, and glaciers terminating in the ocean showed an increase in ice velocity and decrease in area. Terrestrial vegetation productivity has been decreasing since 2011.
Citizen scientists have a new opportunity to help reconstruct past climate by transcribing data from whaling ship logs. A massive collaboration among government and university scientists, archivists and museum curators, has unveiled Old Weather: Whaling, a sister project of Old Weather that is focused on the Pacific Arctic whaling industry that began in 1849. Volunteers mine massive amounts of sea-ice and weather data from the ship’s logs -- along with amazing stories of the Arctic whalemen. These data are fed to state-of-the-art retrospective analysis (reanalysis) systems and provide ground-truth for sea-ice and climate models, all contributing toward better understanding of the Arctic climate of the future.
Starting Nov. 21st, NOAA PMEL, UW/JISAO and OSU/CIMRS scientists will explore the Mariana Back-arc, a volcanically active region expected to be teeming with life. Research will take place aboard the Schmidt Ocean Institute’s Falkor and will use the autonomous underwater vehicle (AUV) Sentry and CTD to detect and characterize hydrothermal vents found in the region. The team will start by surveying and identifying active vent sites along the Mariana back-arc, and will characterize each site by depth, geologic setting, temperature, chemical composition, and rise heights of hydrothermal plumes. A follow-up expedition next year will use the results found in this survey, and return to use a remotely operated vehicle (ROV) to explore and sample the new sites found during this cruise.
Monitoring baseline ocean noise is critically important to understand both natural and anthropogenic changes in the marine ambient sound environment. As of this week, a network of 11 ocean noise reference stations has been established in U.S. waters to measure changes and trends in natural and man-made ocean noise. Natural sounds ranging from whale calls and volcanoes to anthropogenic sounds from shipping and oil/gas exploration are recorded by the moored, underwater hydrophones developed by PMEL engineers and scientists and deployed in collaboration with NMFS-OST, all the Fisheries Science Centers, NOS Marine Sanctuaries, and the National Park Service. The establishment of a long-term record provides fundamental data needed to understand how increased noise in the ocean may affect marine life and ocean health.