What's New Archive
The U.S. West Coast continental shelf is known to host methane bubble streams, formerly thought to be rare. However, results of a recently published paper indicate that nearly 3,500 methane bubble streams, clustered into more than 1,300 methane emission sites, emanate from the seafloor from the Strait of Juan de Fuca in the north to the Mendocino Fracture Zone off northern California in the south, in an area known as the Cascadia Margin. Derived from data collected during multibeam mapping surveys on Ocean Exploration Trust's Exploration Vessel (E/V) Nautilus, the University of Washington's Research Vessel (R/V) Thompson, NOAA Ship Rainier and historical data, the discovery sheds new light on the extent and distribution of seafloor methane seeps. These seeps may provide important habitat for marine life and could play an important role in ocean warming.
The results, published in Frontiers of Earth Science by scientists from the Oregon State University-NOAA Cooperative Institute for Marine Resources Studies (CIMRS) with PMEL's Earth-Ocean Interactions Program, University of Washington, U.S. Naval Research Lab at Stennis Space Center, and Ocean Exploration Trust, provide a major contribution to the first systematic “baseline” survey of methane seeps published over such a large area, representing over 40% of the 93,000 square kilometers (35,900 square miles) of the U.S. Cascadia margin.
Until recently, the number and distribution of methane seep sites in the northeast Pacific across depth and latitude was very poorly known, with previous estimates of methane seeps, based largely on historical fisheries survey data, suggesting about a thousand seeps existed along the U.S. Cascadia Margin.
In the Frontiers of Earth Science paper, scientists present the analyses of detailed seafloor and co-registered acoustic water column data from eight large-scale multibeam sonar surveys on the U.S. Cascadia Margin with previous historical data. The analyses resulted in a remarkably detailed view of where the 3,500 bubble streams (clustered into 1,300 methane emission sites) are located as well as the seafloor features associated with the seeps.
The methane sites are concentrated in water depths less than 800 meters (2,625 feet), although sites are also found in water as deep as 2,070 meters (6,790 feet) and as shallow as 40 meters (130 feet). In waters along the Cascadia Margin, methane hydrate is stable at depths greater than about 500 meters (1,640 feet) and is unstable at shallower depths.
The importance of these methane seeps goes beyond the numbers. These seeps host chemosynthetic communities, build rocky carbonate hard grounds that are essential fish habitat, and release an unknown quantity of methane to the ocean and potentially to the atmosphere, where it acts as a powerful greenhouse gas. This new seep compilation provides a baseline to evaluate possible future increasing methane gas flux as ocean waters warm and drive what is known as the methane hydrate stability zone deeper, releasing additional methane from its ice-like form.
As methane seeps are likely ubiquitous on most or all continental margins, this study literally provides a map for more detailed studies of the ecological importance of methane seeps along the west coast of the United States.
The database of all the combined methane bubble streams and clustered emission sites is publicly available on PMEL Earth Ocean Interaction Program website
This summer and fall, some of the co-authors and other members of NOAA PMEL, University of Washington, and Oregon State University will participate in another Nautilus Cascadia Margin expedition as well as in the West Coast Ocean Acidification expedition aboard NOAA Ship Ron Brown. More data will be acquired for addition to this new database in order to better understand any potential impacts of methane seeps in the water column and to test new technologies.
Originally posted on NOAA Ocean Exploration.
A new Old Weather project is now available on the Zooniverse citizen-science platform recovering weather data collected by U.S. Navy ships during World War II (1941-1945) that will drive sophisticated computer models used to reconstruct past weather events and improve future global climate projections. New information gathered through this project will also help uncover the source of a mysterious anomaly in sea-surface temperatures measured during the war. This distortion, known as the World War II Warm Anomaly, is large enough to affect the long-term global mean sea-surface temperature record, and ultimately impacts how we understand climate variability over longer time periods.
It is currently thought the warm ocean temperatures that appeared during World War II are not actually real, but arise due to changes in the way sea-surface temperatures were collected and then compiled into the digital data sets we use today. A critical barrier to verifying and quantifying the effect of different sampling methods used during this period has been the limited access to the original logbooks kept aboard every Navy ship.
Fortunately, most of the ships’ deck logs and war diaries have been preserved by the U.S. National Archives; these have gradually been digitized and published online via a longstanding collaboration with NOAA and the University of Washington’s Cooperative Institute for Climate, Ocean & Ecosystem Studies (CICOES). Online access and Old Weather citizen-scientists’ transcriptions enable entirely new analyses of the marine weather data collected by the Navy during World War II and even as far back as the 1850s.
The ship logbooks being transcribed via the Old Weather – WWII project were chosen not only to provide new-to-science data for the world’s climate data bases, but specifically to help answer questions about the nature of the data itself during this period. The selected ships are representative of the main classes of warship that were in use, and they share some particular characteristics. The most important – these ships were operating together, often within sight of each other, through much of the war. Twelve of the ships were based at Pearl Harbor in 1941, eighteen were in the Aleutian Islands in 1942-1943, and ten were caught in Typhoon Cobra in December 1944. Their proximity in time and space will allow us to investigate for the first time underlying factors associated with the weather data: the potential effect of different ship types, the different weather instruments in use, and changes in methods required by wartime operations, such as darkened ship (blackout).
Once analyzed, these data will allow the research team to quantify the impact of data collected by the Navy during World War II on the global sea-surface temperature record. If the current hypothesis that the warm anomaly is not physical is shown to be correct, the bias-adjusted temperature record would then appear to rise more smoothly through the 20th century. Reconstructions of the atmosphere produced by retrospective analysis (reanalysis) that depend on historical data would also be improved.
The team behind this project: Kevin Wood (University of Washington and NOAA/PMEL), Ed Hawkins and Praveen Teleti (National Centre for Atmospheric Science at the University of Reading), Philip Brohan (UK Met Office), Gil Compo (University of Colorado/NOAA PSL) and Mark Mollan (U.S. Coast Guard Historian’s Office).
A simulated red dye tracer released from the Beaufort Gyre in the Arctic Ocean (center top) shows freshwater transport through the Canadian Arctic Archipelago, along Baffin Island to the western Labrador Sea, off the coast of Newfoundland and Labrador, where it reduces surface salinity. At the lower left is Newfoundland (triangular land mass) surrounded by orange for fresher water, with Canada’s Gulf of St. Lawrence above colored yellow. Credit: Francesca Samsel and Greg Abram (LANL)
The Beaufort Gyre in the western Arctic Ocean is the largest oceanic freshwater reservoir in the Northern Hemisphere. It has increased its freshwater content by 40% over the past two decades. The fate of the excess freshwater and how and where this water will flow into the Atlantic Ocean is important for local and global ocean conditions. A new paper in Nature Communications, researchers from the University of Washington, NOAA's Pacific Marine Environmental Laboratory and the Department of Energy Los Alamos National Laboratory, show that a historical release during 1983-1996 freshened the western Labrador Sea by as much as 0.2 parts per thousand. The results imply that a future release of the current high volume of Beaufort Gyre freshwater could even be more impactful.
This study is the first that quantifies the fate of the Beaufort Gyre freshwater after it is released and its downstream impact. The study shows that this freshwater travels through the Canadian Archipelago to reach the Labrador Sea, rather than through the wider marine passageways that connect to seas in Northern Europe. The results are based on passive tracers implemented in a global intermediate-resolution ocean sea-ice model, which is performed at the High Performance Computing facility at Los Alamos National Laboratory.
“The Canadian Archipelago is a major conduit between the Arctic and the North Atlantic,” said lead author Jiaxu Zhang, a UW postdoctoral researcher at the Cooperative Institute for Climate, Ocean and Ecosystem Studies who began this work at Los Alamos National Laboratory. “In the future, if the winds get weaker and the freshwater gets released, there is a potential for this high amount of water to have a big influence in the Labrador Sea region.”
The finding has implications for the Labrador Sea marine environment, since Arctic water tends to be fresher but also rich in nutrients. This pathway also affects larger oceanic currents, namely a conveyor-belt circulation in the Atlantic Ocean in which colder, heavier water sinks in the North Atlantic and comes back along the surface as the Gulf Stream. Fresher, lighter water entering the Labrador Sea could slow that overturning circulation.
“We know that the Arctic Ocean has one of the biggest climate change signals,” said co-author Wei Cheng at the UW-based Cooperative Institute for Climate, Ocean and Atmosphere Studies. “Right now this freshwater is still trapped in the Arctic. But once it gets out, it can have a very large impact."
The exact impact is unknown. The study focused on past events, and current research is looking at where today’s freshwater buildup might end up and what changes it could trigger.
Read the full University of Washington News Release.
When a saildrone, an uncrewed, instrumented autonomous vehicle, circumnavigated Antarctica during the winter of 2019, it marked a technological triumph over some of the fiercest marine conditions on Earth. Now, analysis of direct measurements collected during this epic voyage are highlighting questions about the vast circumpolar ocean’s role in storing carbon dioxide. The findings were published in the journal Geophysical Research Letters.
Covering only 30 percent of Earth's ocean surface, the Southern Ocean plays an outsized role in the global climate. It is the meeting point of ocean currents, and an important connector between the atmosphere and deep ocean for the transfer of heat and carbon. Based on measurements collected from ships over several decades, scientists concluded that the Southern Ocean is a major buffer against climate change, absorbing as much as 75 percent of the excess heat and 40 percent of human-generated carbon dioxide (CO2) emissions taken up by the global oceans.
More recently though, biogeochemical measurements taken by autonomous Argo floats between 2014 and 2017 suggest the Southern Ocean’s role as a carbon “sink” that absorbs CO2 is much smaller - perhaps barely any sink at all, said Adrienne Sutton, an oceanographer with NOAA’s Pacific Marine Environmental Laboratory, who is investigating the discrepancy between ship and float data. “If we’re wrong about the Southern Ocean being a strong sink, then where’s all that carbon dioxide going?” Sutton asked. “The answer is important for understanding how the Earth system is responding to climate change.”
Ocean measurements are key to understanding the global carbon cycle, and how the natural ocean and land serve as sinks for carbon and are responding to climate change driven by concentrations of CO2 in the atmosphere. By directly measuring wind speed, along with CO2 in the air and surface seawater, scientists were able to observe CO2 exchange between the ocean and atmosphere every hour during the mission. Using these data, they estimated potential errors in these measurements, as well as potential errors due to other approaches to estimating CO2 exchange.
Although data showed the ocean was both absorbing and emitting CO2 during the voyage, outgassing was prevalent during late fall and early winter in the Indian Ocean sector of the Antarctic Zone, which comprised about one third of the route.
“The outgassing we measured in 2019 was not as strong as the outgassing measured by Argo biogeochemical floats in this same region in 2014 and 2015, so we expect that CO2 flux conditions are highly variable from year to year,” Sutton said.
Read the full story on NOAA Research.
Shelled pteropods, microscopic free-swimming sea snails, are widely regarded as indicators for ocean acidification because research has shown that their fragile shells are vulnerable to increasing ocean acidity. Sometimes called sea butterflies because of how they appear to flap their “wings” as they swim through the water column, fat-rich pteropods are an important food source for organisms ranging from other plankton to juvenile salmon to whales. They make shells by fixing calcium carbonate in ocean water to form an exoskeleton.
A new study, published in the journal Scientific Reports, shows that pteropods sampled off the coasts of Washington and Oregon made thinner shells than those in offshore waters. Along the coast, upwelling from deeper water layers brings cold, carbon dioxide-rich waters of relatively low pH to the surface. The research team of Dutch and American scientists found that the shells of pteropods collected in this upwelling region were 37 percent thinner than ones collected offshore.
“It appears that pteropods make thinner shells where upwelling brings water that is colder and lower in pH to the surface, ” said lead author Lisette Mekkes of Naturalis Biodiversity Centers and the University of Amsterdam in the Netherlands. Mekkes added that while some shells also showed signs of dissolution, the change in shell thickness was particularly pronounced, demonstrating that acidified water interfered with pteropods’ ability to build their shells.
The scientists examined shells of pteropods collected during the 2016 NOAA Ocean Acidification Program research cruise in the northern California Current Ecosystem onboard the NOAA Ship Ronald H. Brown. Shell thicknesses of 80 of the tiny creatures - no larger than the head of a pin - were analyzed using 3D scans provided by micron-scale computer tomography, a high-resolution X-ray technique. The scientists also examined the shells with a scanning electron microscope to assess if thinner shells were a result of dissolution. They also used DNA analysis to make sure the examined specimens belonged to a single population.
"Pteropod shells protect against predation and infection, but making thinner shells could also be an adaptive or acclimation strategy," said Katja Peijnenburg, group leader at Naturalis Biodiversity Center. "However, an important question is how long can pteropods continue making thinner shells in rapidly acidifying waters?"
The California Current Ecosystem along the West Coast is especially vulnerable to ocean acidification because it not only absorbs carbon dioxide from the atmosphere, but is also bathed by seasonal upwelling of carbon-dioxide rich waters from the deep ocean. In recent years these waters have grown increasingly corrosive as a result of the increasing amounts of atmospheric carbon dioxide absorbed into the ocean.
“Our research shows that within two to three months, pteropods transported by currents from the open-ocean to more corrosive nearshore waters have difficulty building their shells,” said Nina Bednarsek, a research scientist from the Southern California Coastal Water Research Project in Costa Mesa, California, a coauthor of the study.
Over the last two-and-a-half centuries, scientists say, the global ocean has absorbed approximately 620 billion tons of carbon dioxide from emissions released into the atmosphere by burning fossil fuels, changes in land-use, and cement production, resulting in a process called ocean acidification.
“The new research provides the foundation for understanding how pteropods and other microscopic organisms are actively affected by progressing ocean acidification and how these changes can impact the global carbon cycle and ecological communities,” said Richard Feely, NOAA Pacific Marine Environmental Laboratory and chief scientist for the cruise.
NOAA’s 15th Arctic Report Card catalogs for 2020 the numerous ways that climate change continues to disrupt the polar region, with second-highest air temperatures and second-lowest summer sea ice driving a cascade of impacts, including the loss of snow and extraordinary wildfires in northern Russia. The sustained transformation to a warmer, less frozen and biologically changed Arctic remains clear.
The average annual land-surface air temperature in the Arctic measured between October 2019 and September 2020 was the second-warmest since record-keeping began in 1900, and was responsible for driving a cascade of impacts across Arctic ecosystems during the year. Nine of the past 10 years saw air temperatures at least 1 degree C above (2.2 degrees F) the 1981-2010 mean. Arctic temperatures for the past six years have all exceeded previous records.Record warm temperatures in the Eurasian Arctic were associated with extreme conditions in the ocean and on the land.
Sea ice loss in spring 2020 was particularly early in the East Siberian Sea and Laptev Sea regions, setting new record lows in the Laptev Sea for June. The end of summer sea ice extent in 2020 was the second lowest in the 42-year satellite record, with 2012 being the record minimum year. Overall thickness of the sea ice cover is also decreasing as Arctic ice has transformed from an older, thicker, and stronger ice mass to a younger, thinner more fragile ice mass in the past decade.
PMEL’s Dr. James Overland, Dr. Muyin Wang (UW/CICOES), and Dr. Kevin Wood (UW/CICOES) contributed to sections on surface air temperature and sea ice. Dr. Overland is one of three founding editors of the Arctic Report Card and served as a co-editor from 2006 - 2017. Read the full interview about his work in the Arctic and with the Arctic Report Card.
The Arctic Report Card is an annual compilation of original, peer-reviewed environmental observations and analyses of a region undergoing rapid and dramatic alterations to weather, climate, oceanic, and land conditions. Compiled by 133 scientists from 15 countries, the 2020 report card tracks environmental indicators to inform decisions by local, state and federal leaders confronting a rapidly changing climate and ecosystems.
Read the original NOAA Press Release.
Satellite sea surface temperature departure for October 2015 over the Pacific. Orange-red colors indicate above normal temperatures, indicative of an El Niño condition. The 2015-16 El Niño was the first extreme El Niño of the 21st century and among the three strongest El Niños on record. Credit: NOAA National Environmental Satellite, Data, and Information Service (NESDIS)
The El Niño Southern Oscillation (ENSO) in the Pacific Ocean has major worldwide social and economic consequences through its global scale effects on atmospheric and oceanic circulation, marine and terrestrial ecosystems, and other natural systems. It is the most dramatic year-to-year variation of the Earth’s climate system, affecting agriculture, public health, freshwater availability, power generation, and economic activity in the United States and around the globe. Ongoing climate change is projected to significantly alter ENSO’s dynamics and impacts.
The future of ENSO is the subject of a new book published by the American Geophysical Union. With 21 chapters written by 98 authors from 58 research institutions in 16 countries, the volume covers the latest theories, models, and observations, and explores the challenges of forecasting El Niño and La Niña. The book, “El Niño Southern Oscillation in a Changing Climate” was published online on November 2.
“This is the first comprehensive examination of how ENSO, its dynamics and its impacts may change under the influence of rising greenhouse gas concentrations in the atmosphere,” said Michael McPhaden, senior scientist with PMEL's Global Tropical Moored Buoy Array, and co-editor of the new volume. Two other co-editors are from Australia: Agus Santoso, a scientist with the University of New South Wales, and Wenju Cai, a researcher with the Commonwealth Scientific and Industrial Research Organisation, also known as CSIRO.
The new book, three years in the making, tracks the historical development of ideas about ENSO, explores underlying physical processes and reveals the latest science on how ENSO responds to external factors such as climate phenomena outside the tropical Pacific, volcanic eruptions, and anthropogenic greenhouse gas forcing.
How are ENSO impacts likely to evolve in the coming decades?
“Extreme El Niño and La Niña events may increase in frequency from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios,” McPhaden said. “The strongest events may also become even stronger than they are today.”
In a warming climate, rainfall extremes are projected to shift eastward along the equator in the Pacific Ocean during El Niño events and westward during extreme La Niña events. Less clear is the potential evolution of rainfall patterns in the mid-latitudes, but extremes may be more pronounced if strong El Niños and La Niñas increase in frequency and amplitude, he said.
Some ENSO impacts are already being amplified, such as the extensive coral bleaching and increases in tropical Pacific storm activity observed during the 2015-16 El Niño. ENSO is expected to impact tropical cyclone genesis in the future as it does today in the Atlantic, Pacific and Indian Oceans, but precisely how is still an open question.
To learn more about El Nino and La Nina and the research PMEL does, visit https://www.pmel.noaa.gov/elnino/pmel-research-activities
NOAA scientists and crew on NOAA Ship Oscar Dyson deploy a mooring in the Bering Sea to monitor ocean acidification in 2019. Moorings give researchers an expanded view of the remote corners of the world's ocean sproviding near-continuous, year-round measurements. Credit: NOAA Corps LT Laura Dwyer/ NOAA.
From spring to early fall in a typical year, NOAA and research partners conduct several important scientific surveys in the U.S. waters of the Bering and Chukchi Seas. Scientists collect oceanographic and biological data that are used to inform fisheries management, monitor whale populations and support Arctic ecosystem and climate studies.
This annual research is essential to understanding a rapidly changing Arctic.
But this was no usual year due to the COVID-19 pandemic. While NOAA has had to cancel many of its planned research surveys in Alaska, it has been able to conduct a number of scaled-back research surveys in 2020. One such survey that will be finishing up this week is in the Arctic and was conducted on board NOAA Ship Oscar Dyson to collect critical data supporting a long time series involving many scientific partners.
Collecting key Arctic data
With the help of the Oscar Dyson’s crew, which has gone above and beyond their normal duties to assist the scientists during the survey and ensure the continued collection of data, scientists are retrieving and deploying some of the moorings that gather data year-round in the Bering and Chukchi Seas. These moorings are equipped with sensors to collect measurements of nutrients and oceanographic conditions (including currents, temperature, salinity, oxygen, and fluorescence) to better understand the health of this marine ecosystem and how it may be changing. Some of the mooring sites have been operating continuously for more than 20 years and provide critical ocean measurements during the ice-covered winter and spring months.
The science team and Oscar Dyson survey team are also collecting physical, chemical and biological water column data in an effort to document ongoing ecosystem changes in the U.S. Arctic. The science team is also sampling the water column for phytoplankton, single-celled plants, in order to monitor harmful algal blooms and are collecting environmental DNA from water samples to document the biodiversity present in the environment.
Gaining insights on marine life
Scientists at the Alaska Fisheries Science Center also hope to retrieve passive acoustic data from year-round moorings to learn more about where whales move throughout the year. Of particular interest is how whales responded to a more typical, colder winter in 2019 than the extremely warm conditions during the previous two years.
The survey team deployed new pop-up floats for NOAA’s Pacific Marine Environmental Laboratory to map the “cold pool”. The cold pool is a layer of cold bottom water (less than 35°F (2 °C) at approximately 98 feet (30 meters), which results from melting sea ice in the previous winter and spring, and plays a key role for the Bering Sea ecosystem. It can act as a corridor for Arctic fish species and a barrier for sub-Arctic species. The cold pool can restrict movement of commercially important walleye pollock and Pacific cod into northern waters. In the past few years, the cold pool has been markedly smaller, allowing large-scale northward expansions of typically sub-Arctic fish, crab and zooplankton into the Bering Sea.
“What is really remarkable about this survey is that scientists and crew are stepping forward to collect data for fellow scientists who aren’t able to get out this year,” said Phyllis Stabeno, NOAA PMEL oceanographer. “It’s a great example of teamwork at its best.”
The Oscar Dyson team has already retrieved four seafloor-mounted acoustic moorings for Alex De Robertis, an Alaska Fisheries Science Center fisheries biologist. Data collected by these moorings will help quantify the migrations of walleye pollock between U.S. and Russian waters.
Read more about the research cruise on NOAA Research.
After 8 months of sitting on the seafloor, PMEL’s latest engineering development, the Flotation Controllable Ocean Mooring (FCOM) system successfully resurfaced in July. Over the last two years, PMEL has been developing a profiling mooring for use in Arctic regions that submerges when ice arrives in the fall and refloats in the spring after ice retreat. The FCOM system has a surface float that is anchored to the ocean floor, and includes a Prawler that moves up and down the mooring line collecting profiles of temperature, salinity, chlorophyll, and dissolved oxygen. This innovation will provide real-time information of the full water column during the entire open water (sea ice free) season.
The Chukchi Sea is an ice-driven system. Collecting data during the spring and fall is crucial for monitoring ecosystem production and generating ice forecasts. Data collection during spring and fall is difficult as there are few vessels in the region during those times, and moorings must be placed near the seafloor to avoid ice keels which prevents real time data return on the status of the full water column. Prior to FCOMs, surface floats could only sample for a short period because deployment and recovery were dependent upon the tight scheduling of research vessels. This mooring addresses these long-standing science gaps.
The mooring was originally deployed from the R/V Ocean Starr in spring of 2019 in the Chukchi Sea with pre-programmed dates to sink and resurface. It sank in October 2019, resurfaced in July 2020 and will be recovered in September. The next version of FCOM will be outfitted with a hydrophone and ice-detection algorithms so that it can resurface after ice retreats without having a pre-programmed date. Ultimately, the FCOM with a Prawler is intended to be integrated into NOAA’s Arctic observing system.
The surface mooring at the Kuroshio Extension Observatory (KEO), which broke away from its anchor on May 19, was recovered on July 21 by the Japanese charter ship, Kaiyo. Despite being caught in eddies and an ocean jet, the drifting KEO buoy, its sensor suite and nearly 8 kilometers of mooring line was recovered. Due to travel restrictions associated with COVID19, there were no NOAA personnel onboard the Kaiyo for this rescue. This mission relied on a large contingent for its success, including the assistance of engineers, technicians and administrative staff at NOAA’s Pacific Marine Environmental Laboratory (PMEL), funding from NOAA Research’s Global Ocean Monitoring and Observing (GOMO), partners at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), and the Kaiyo captain and crew.
The KEO station is located off the coast of Japan. NOAA has maintained a surface mooring there since 2004, and JAMSTEC has maintained a subsurface sediment trap at KEO since 2014. The KEO surface mooring carries a suite of instrumentation to monitor air-sea exchanges of heat, moisture, momentum (wind stress), and carbon dioxide; surface ocean acidification; and upper ocean temperature, salinity and currents. This region has some of the largest air-sea heat and carbon dioxide fluxes in the world’s ocean. The KEO station is an important reference data set for assessing satellite observations, numerical weather prediction and climate models. Its data are being used worldwide to better understand weather, climate, and the carbon cycle.