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  • richardmitnick 12:11 pm on December 6, 2017 Permalink | Reply
    Tags: , , Eddy currents: enter the whirlpool, Oceanography, Where do ocean eddies come from?   

    From CSIROscope: “Eddy currents: enter the whirlpool” 

    CSIRO bloc

    CSIROscope

    5 December 2017
    Sophie Schmidt

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    “Can you spot the eddies? This NASA image shows a field of eddies in the waters around Tasmania. The swirling motion of eddies in the ocean cause nutrients that are normally found in colder, deeper waters to come to the surface. Here, phytoplankton (tiny ocean plants) feeding on these nutrients color the water beautiful shades of blue and green.” Image: National Oceanic and Atmospheric Administration.

    What do the Sydney to Hobart Yacht Race and the Australian freshwater eel have in common? Every year, they head out of the confines of Sydney Harbour to the wild depths of the ocean on the ride of their lives.

    The Australian freshwater eel migrates north, swimming from far up the rivers on the east coast of Australia, eventually out to the ocean where it heads to the Coral Sea. Once there, it spawns abundant, tiny translucent larvae, which then hatch and embark on the big commute back to their mothers’ home.

    With distances up to 1500 km, it might sound like a very long way to go just to lay some eggs and raise your offspring – but for both parties (the Yacht crews ideally don’t produce spawn along the Bass Straight) the round-trip from their home to their destination and back again is made much easier, thanks to an ocean phenomenon called eddies.

    We’re not talking about legendary AFL player Eddie Betts or even this home energy tool we developed – we’re talking about ocean whirlpools that play a stunningly important role in the ecosystem, transporting heat, nutrients, salt and marine animals (including humans) around the ocean.

    Where do ocean eddies come from?

    The ocean is pretty darn big, and because of the nature of shifting wind cycles, it’s constantly in motion. We call these general patterns of motion currents.

    Australia’s major current systems include the East Australian Current in the east (made famous by some fishy friends hitching a ride in Finding Nemo), the Leeuwin Current in the west, and currents that connect the Pacific and Indian Oceans via the Indonesian Passages and in the Southern Ocean.

    Eddies peel off from boundary currents, and form in energetic ‘bowls’, hundreds of metres deep and hundreds of kilometres wide. The strongest currents in the deep ocean are found at the outer edge of these eddies, like winds around the highs and lows in the atmosphere. Although the currents are strong, the eddies themselves are more like gentle giants slowly moving through ocean, taking months to travel from Sydney to Bass Strait.

    Australia – home of the eddies

    Australia is unusual because we have two strong boundary currents: the Leeuwin in the west and the East Australian Current in the east. And where there are strong ocean currents, there are eddies. The region of southern NSW has actually been nicknamed Eddy Ave because of all the eddies that form there.

    For those crews sailing in the Sydney to Hobart Yacht race on Boxing Day, hitching a ride on an eddy can either slingshot them towards Hobart’s finish line, or push them back towards Sydney – depending on the direction of the rotation of the currents around the eddy.

    But what’s so fascinating about eddies is that they’re associated with upwelling, which can bring key nutrients from the deep, dark waters up to the surface of the ocean.

    Taking a sea change

    An upwelling sounds quite ominous, but in reality, it’s like a big family holiday destination for marine life.

    Our oceans are complex, inter-related communities of plants and animals. And when some eddies form, cold, nutrient-rich water can rise up from below to replace the surface water.

    Just like stirring a big pot of soup where the really good stuff is hanging around on the bottom, upwelling renews the nutrient supplies of the top-level surface, kick-starting a renewal of the food supply, which benefits many organisms in turn.

    How? It starts by the providing essential nutrients to phytoplankton (tiny ocean plants known as microalgae), which live near the surface. Phytoplankton provide a convenient food source full of fatty acids for many of the ocean’s invertebrates and fish species, including eel, yellow tail king fish, anchovy and dolphin.

    Because upwelling can trigger an increase in phytoplankton production, eddies produce enhanced conditions for breeding, and so are associated with an increase in spawning activity for many larval species.

    Spanning up to 50-200 km wide, eddies can sustain themselves anywhere from a number of weeks to a number of months, functioning as bustling oases for baby marine animals.

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    Eddies provide essential nutrients to phytoplankton. Image: Neon Ja

    Our research

    When our atmosphere system changes significantly so as to affect the development of eddies, it can in turn have dramatic effects on the ocean circulation, which can have a big effect on the ocean’s ecosystem, and as a result, our weather patterns.

    One of the most useful tools for understanding eddies is the Argo fleet, which floats around the ocean measuring the temperature and salinity of the surface – up to 2 km in depth.

    Over the past twenty years we have been able to observe eddies in the ocean with satellite altimeters and in that time we have seen some significant changes in the number of eddies coming south past the Bass Strait, down to Tasmania. At the same time, we’ve observed that the temperature on the east coast of Tasmania has been warming. In 2015/16, a marine heat wave took place, which has impacted on the health of Tasmania’s kelp forests.

    So, whether it’s about finding the most strategic route down to Hobart, or looking for the best fishing grounds, it’s important that we study ocean currents and eddies in order to sustainably manage our marine resources and understand how the global ocean circulation is likely to change over the decades to come.

    See the full article here .

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    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

    So what can we expect these new radio projects to discover? We have no idea, but history tells us that they are almost certain to deliver some major surprises.

    Making these new discoveries may not be so simple. Gone are the days when astronomers could just notice something odd as they browse their tables and graphs.

    Nowadays, astronomers are more likely to be distilling their answers from carefully-posed queries to databases containing petabytes of data. Human brains are just not up to the job of making unexpected discoveries in these circumstances, and instead we will need to develop “learning machines” to help us discover the unexpected.

    With the right tools and careful insight, who knows what we might find.

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

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  • richardmitnick 7:56 pm on October 6, 2017 Permalink | Reply
    Tags: , , , Long floating arrays of hydrophones pick up the sound waves, Marine seismic surveys, Ocean bottom seismometers, Oceanography, Seventy percent of Earth’s surface geology is under water,   

    From Eos: “Keeping Our Focus on the Subseafloor” 

    AGU bloc

    AGU
    Eos news bloc

    Eos

    3 October 2017
    Nathan Bangs and
    James A. Austin Jr.

    1
    University of Texas at Austin Ph.D. students Kelly Olsen and Brooklyn Gose work on recovering, cleaning, and storing 1 of 50 streamer depth control birds on the back deck of the R/V Langseth during a marine seismic survey cruise. Although relatively few scientists go to sea to collect such data themselves, the data from these surveys provide valuable information on subseafloor structures to a much wider scientific community. Credit: Nathan Bangs

    Seventy percent of Earth’s surface geology is under water, but let’s face it: There are few options for exploring beneath the seafloor, and the limited number of techniques for subseafloor exploration presents a challenge. But with modern seismic imaging techniques it’s surmountable, and the opportunities are extremely exciting.

    The real challenge at present is finding financial support. We need a new funding commitment in the United States to address recent declines in National Science Foundation (NSF) seismic facilities support. We are at a juncture where an increment of additional support from U.S. funding agencies, academic institutions, and/or private contributions for seismic facilities will have a leveraging effect with tremendous science impact for a broad community. With less support, we will still progress, but with substantial new challenges and uncertainty throughout marine science.

    During marine seismic surveys, ships use pneumatic sound sources to generate acoustic waves beneath the water’s surface. Long floating arrays of hydrophones pick up the sound waves, reflected back by subsurface sedimentary layers and crustal structures, to provide a detailed picture of the geology below the ocean floor.

    This technique provides invaluable information for the scientific and petroleum exploration communities alike. However, research funding reductions continue to hamper the marine geoscience community’s ability to collect seismic data in areas of scientific interest.

    Although relatively few scientists are directly involved in collecting these data, a much larger community relies on the data they produce. Thus, a dwindling data stream produces ripple effects that extend far beyond the scientists and crews who go to sea.

    The science community needs to understand what those ripple effects mean. Below, we’ve outlined a few options that we see as the most likely going forward.

    Seismic Techniques Provide Context

    Data from beneath the ocean floor come from several sources, and each type has its own strengths and limitations.

    Drilling and piston coring provide valuable samples for establishing lithologies, ages, geochemistry, and physical properties, but they provide a keyhole view beneath the ocean floor. Cores are only a few centimeters wide, and the information we gain is generally limited by both depth of penetration and the cost of coring expeditions.

    Electromagnetic methods are designed for a broader view, but they provide only bulk property constraints, averaged over the sampling area.

    The reality is that only marine seismic data have the resolution to see into the subsurface, to reveal regional geologic structure, and to help us understand the broader context of “ground truth” sampling from cores.

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    Coherence volume derived from the Costa Rica 3-D seismic data acquired on the R/V Langseth in 2011. These data show amazing 3-D detail in the subseafloor geology. Dark lines indicate the disruption in the continuity of seismic reflections from a complex pattern of faulting (mostly normal faults here) within margin shelf and slope cover sediment sequences. Horizontal slices are at 455 and 1,060 m depth. Credit: Nathan Bangs

    We have some amazing seismic data analysis techniques available to us: 3-D imaging, full-waveform inversion, and vertical profiling. We also have technologies to gather these data: Large spatial deployments of ocean bottom seismometers (OBSs), for example, are now possible with governmentally supported OBS instrument pools in the United States and other countries. Advanced multichannel seismic (MCS) reflection platforms, like the United States’ R/V Marcus G. Langseth, are equipped with multiple hydrophone arrays and streamers, which can be as long as 15 kilometers. And we have improved computational facilities for data analyses.

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    United States’ R/V Marcus G. Langseth. https://marine.usgs.gov

    Together, these capabilities allow us to “see” into the subseafloor to address fundamental geologic questions on ocean crust formation and evolution, subduction zone earthquake genesis, fluid migration within the crust, continental rifting, and the list goes on.

    More Technology but Fewer Cruises

    However, the availability of high-quality seismic images is in decline. The International Ocean Discovery Program (IODP) Science Evaluation Panel (SEP), scientific ocean drilling’s primary review body, sent the following statement for programmatic review in 2015:

    “The SEP wishes to convey concern regarding the increased pressures on the acquisition of academic active-source seismic data, some of which by design is conducted in support of scientific ocean drilling. Continued reduction in the international marine geoscience communities’ ability to collect seismic data in areas of scientific interest is jeopardizing the scope and impact of IODP science. The SEP consensus is that the IODP should stress the importance, both to member country funding agencies and environmental permit organizations worldwide, of high-quality subsurface images for science and safety in connection with expected continuation of IODP.”

    The SEP concern is justified. From 1995 to 2005, the R/V Maurice Ewing, then the primary U.S. seismic acquisition facility, conducted on average 4.7 seismic (MCS and OBS) cruises each year (in addition to higher-resolution surveys) and participated in multiship vertical seismic profiling projects.

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    R/V Maurice-Ewing (Photo courtesy Lamont-Doherty Earth Observatory of Columbia University)

    In contrast, during the past decade, the R/V Marcus G. Langseth, the Maurice Ewing’s successor ship, has conducted an average of 3.2 cruises each year, with only 5 total in 2016 and 2017.

    This decline raised questions explicitly addressed in the 2015 National Academy of Sciences’ decadal survey of ocean sciences: Should the National Science Foundation consider divestiture of this expensive facility to maintain a healthy balance between spending on technology and infrastructure and spending on science? Are seismic facilities serving too few scientists to justify such infrastructure?

    Worth the Investment?

    To address these questions, the University–National Oceanographic Laboratory System (UNOLS) conducted a June 2016 survey to assess the community’s seismic needs. Response was excellent; in 2.5 weeks, 263 completed the survey. (As a comparison, the virtual town hall that surveyed the ocean sciences community as input to the National Academy of Sciences report generated about 400 responses over 20 weeks.)

    The UNOLS survey confirmed that although a minority of the respondents acquire data at sea, and most of those are senior scientists (at least 20 years post Ph.D.), the seismic data they collect are used by many more. Half of the respondents considered themselves nonspecialists who rely only on processed seismic data and interpretations, without other involvement.

    The majority of respondents had never submitted an NSF proposal to acquire seismic data; 75% had not served as a primary investigator (PI) or co-PI on a seismic acquisition and processing project in the previous 5 years. Many stated that they do not have the background to acquire seismic data. However, 94% said they plan to use seismic data in the future, primarily through collaborations.

    The most commonly cited reason for not serving as a PI on a Langseth-type acquisition cruise was a lack of background in seismology or know-how with acquisition, processing, and interpretation techniques. Processing seismic reflection data requires extensive technical knowledge, advanced computer systems equipped with appropriate (often expensive) software, and generally 1–2 years or more of postacquisition processing effort.

    Overcoming these challenges is not practical or even possible for many; the pool of seismic specialists will remain small. Yet the UNOLS survey confirms the demand for seismic data beyond the small number of PIs who acquire and process them. Therefore, a loss of acquisition facilities would have wide-reaching effects on Earth sciences.

    The survey also confirms that many seismic tools (Figure 1) are needed to address the diverse science goals of current and envisioned U.S. Earth science programs, some of which include international partners and span shore lines (e.g., IODP, Geodynamic Processes at Rifting and Subducting Margins (GeoPRISMS), and subduction zone observatory).

    Weighing the Options

    Can we maintain seismic acquisition capabilities with reduced funding? With the exception of the Scripps Institution of Oceanography high-resolution (short-streamer) portable MCS system, Langseth is the only U.S. seismic facility. Langseth can acquire 3-D volumes and 2-D data with streamers more than 6,000 meters long, an “aperture” long enough to image at crustal scales.

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    Fig. 1. Results of a June 2016 UNOLS survey to assess the scientific community’s needs for seismic data from the ocean floor and below. Shown here are the percentages of respondents for each type of primary interest and the facilities they use. Multiple responses were allowed. Credit: Nathan Bangs

    In August 2016, the NSF Division of Ocean Sciences distributed a “Dear Colleague” letter stating that “OCE anticipates spending an annual average of ~$8M for ship support and ~$2M for technical support, funding permitting, and supporting seismic infrastructure.” At current Langseth rates, this amounts to operations for some 90 to 112 days, only about 75% of the total 120–150 days per year considered viable for any UNOLS vessel.

    Operating fewer than 120–150 days in a given year actually increases the cost per day. This makes the Langseth operational costs stand out even more while limiting support for the highly experienced crew necessary for state-of-the-art seismic operations.

    Aside from making Langseth a general-purpose vessel and using it to serve other marine science programs, options are limited:

    Option 1. One option is to improve efficiency and increase funding. Since 2015, Langseth has operated according to a long-range framework to minimize transits and maximize opportunities through developing regional and international collaborations. In late 2017 and 2018, Langseth will operate offshore New Zealand, with support from that country, Japan, and the United Kingdom. Unfortunately, international support is limited because partner countries must also support their own facilities.

    Improved efficiency is also possible through sharing facilities internationally. Langseth is currently the most capable academic facility for crustal-scale 2-D/3-D imaging, but it is the only U.S. option for crustal-scale work. International collaboration to exchange Langseth with other international vessels would improve both opportunity and efficiency globally; the Ocean Facilities Exchange Group does this within the European Union.

    A scaled back seismic program will not only affect the PIs who responded to the UNOLS survey, but it will also affect U.S. institutions they represent through loss of NSF support: those who receive funding for seismic data acquisition and those relying on seismic results. Among international programs affected by scaled-back seismic facilities, IODP stands out. Broad support for seismic facilities from U.S. academic institutions would produce returns for these institutions.

    Institutional support could provide Langseth operational costs, but only through collaborative, multiyear commitments. As NSF described in their recent program solicitation “Provision of Marine Seismic Capabilities to the U. S. Research Community,” the agency is committed to providing Langseth or equivalent capabilities, but the proposed funding levels ($10 million per year) would be problematic for the current model. Is any other model viable?

    Option 2. Without Langseth, there will still be exciting science to do, using data from shorter streamers, archived data, and data available (occasionally and in certain areas) from industry.

    Unfortunately, this approach will change the foci of U.S. seismic studies. For example, reduced seismic imaging capability would limit large, successful international programs like IODP. Recent progress on understanding the largest earthquakes and tsunamis on Earth generated at subduction zones will be severely compromised in the future without an ability to see deep subduction zone structures and measure physical properties with seismic tools. Science would need to target shallower settings: submarine landslides, gas hydrates, fluid and gas migration, sea level change, and the like, using cheaper, portable (higher-resolution, smaller) seismic systems.

    Data would be less complicated and easier to process. Higher resolution could even be 3-D, using P-cable systems available from multiple U.S. institutions. However, these systems can rarely deploy streamers long enough or sources powerful enough to fully characterize even shallow stratigraphy and structure, and they can’t address crustal-scale problems at all.

    Going Commercial?

    In 2015, NSF conducted a workshop with invited members from the marine seismic community, primarily the now disbanded Marcus Langseth Scientific Oversight Committee, to consider a long-streamer portable system and commercial contracting. The workshop report concluded that the weight and size of portable systems incorporating long (6–8 kilometer) streamers with moderate-size, tuned acoustic sources made them impractical for current UNOLS vessels.

    Commercial contracting is viable for long-offset 2-D and 3-D acquisition; however, availability could be limited by high costs (especially mobilization costs for work far from oil and gas provinces, where commercial efforts tend to focus), cost volatility, and changes in ship availability due to hydrocarbon market cycles. These cruises would also lack simultaneous multibeam or gravity and magnetics data acquisition, which has historically been available on U.S. seismic vessels, and student training opportunities would be uncertain and problematic.

    Commercial contracting has been used successfully occasionally in the past, but it is risky to rely on contracting to maintain a regular, global crustal-scale acquisition program as we do now.

    Ironically, this development comes at a time when the IODP is increasing its number of operational days. Other exciting developments, such as seafloor geodesy, will also need an understanding of subsurface structure for tectonic context.

    There is considerable imaging science to be done, with or without Langseth. However, the broad impact of scaling back marine seismic facilities on Earth science makes it time to find more financial support for marine seismic acquisition.

    See the full article here .

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    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 8:36 pm on September 21, 2017 Permalink | Reply
    Tags: $19 million grant from the National Science Foundation to study Narragansett Bay, , , Oceanography   

    From Brown: “Brown University scientists to play key roles in new coastal research consortium” 

    Brown University
    Brown University

    September 20, 2017
    Kevin Stacey
    kevin_stacey@brown.edu
    401-863-3766

    1

    Brown University researchers will play key roles in a statewide research consortium, established by a new $19 million grant from the National Science Foundation to monitor and ultimately predict environmental change in Narragansett Bay.

    The Rhode Island Consortium for Coastal Ecology, Assessment, Innovation and Modeling, will bring together research teams from around the Ocean State to study the impacts of climate variability on coastal ecosystems, create innovative technologies for detecting those changes, and build computer models to predict and plan for changes in coastal ecology.

    Geoff Bothun, a professor of chemical engineering at the University of Rhode Island, is the grant’s principal investigator. Jeffrey Morgan, a professor of medicine and engineering at Brown, will serve as one of the grant’s co-principal investigators.

    “Narragansett Bay is an environmental treasure that plays a critical role in the economy of the Ocean State,” Morgan said. “It’s also a natural laboratory that can help us understand how human activities, climate change and other factors drive environmental change. This grant will help us to monitor the bay in unprecedented detail and give us the tools to predict environmental change in the future.”

    Morgan’s work on the grant will pertain to the development of new types of sensors to detect key environmental indicators.

    “We want to be able to make more observations, more often and with greater specificity,” Morgan said. “These sensors will be looking at physical attributes of the bay — things like temperature, salinity and nutrients — as well as markers of biological change like algal blooms and microorganism populations.”

    Baylor Fox-Kemper, an associate professor in Brown’s Department of Earth, Environmental and Planetary Sciences, will lend his expertise to the computer modeling side of the project.

    “There’s a wealth of historical data that captures how the bay has responded to changes in human activity and a changing climate through time,” Fox-Kemper said. “The idea is use that data to build a model of the bay that accurately recreates its past, which we can then use to make predictions.”

    The ultimate aim, Fox-Kemper says, is a model that can predict local-scale events like bacteria counts that result in beach closings, as well as larger scale changes in sea level, tidal patterns, temperature and salinity. The researchers plan to create a data center that will provide access to the observations and model data for scientists as well as government agencies, policymakers and citizen scientists.

    The leaders of the research expect it to have broad impact, especially in a state that relies so heavily on its coastal resources.

    “Research translation and commercialization is also a big emphasis for this grant,” Bothun said. “We’ll be forming an academic-industry partnership to learn about the challenges facing the marine and defense industries, for instance, and share with them some of our discoveries and technologies. This will also be a way to connect students with potential employment opportunities.”

    Morgan says he expects the impact to go well beyond the borders of the Ocean State.

    “We think the collaborative approach we’re developing here in Rhode Island will be a model for the study of coastal resources elsewhere in the U.S. and around the world,” he said. “Equally important, the undergraduates and graduate students we will engage in cutting-edge research that will further strengthen Rhode Island’s pipeline of investigators and innovators.”

    Funding for the project comes from the National Science Foundation’s Established Program to Stimulate Competitive Research (EPSCoR) program, which aims to strengthen states’ research competitiveness and fund workforce development initiatives.

    In addition to the NSF funding, the state of Rhode Island, through Commerce Rhode Island, has committed an additional $3.8 million toward the initiative that will be used to provide collaborative grants and support workforce development.

    See the full article here .

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    Welcome to Brown

    Brown U Robinson Hall
    Located in historic Providence, Rhode Island and founded in 1764, Brown University is the seventh-oldest college in the United States. Brown is an independent, coeducational Ivy League institution comprising undergraduate and graduate programs, plus the Alpert Medical School, School of Public Health, School of Engineering, and the School of Professional Studies.

    With its talented and motivated student body and accomplished faculty, Brown is a leading research university that maintains a particular commitment to exceptional undergraduate instruction.

    Brown’s vibrant, diverse community consists of 6,000 undergraduates, 2,000 graduate students, 400 medical school students, more than 5,000 summer, visiting and online students, and nearly 700 faculty members. Brown students come from all 50 states and more than 100 countries.

    Undergraduates pursue bachelor’s degrees in more than 70 concentrations, ranging from Egyptology to cognitive neuroscience. Anything’s possible at Brown—the university’s commitment to undergraduate freedom means students must take responsibility as architects of their courses of study.

     
  • richardmitnick 12:59 pm on March 22, 2016 Permalink | Reply
    Tags: , Oceanography,   

    From SA: “Massive Network of Robotic Ocean Probes Gets Smart Upgrade” 

    Scientific American

    Scientific American

    March 22, 2016
    Jeff Tollefson, Nature magazine

    Initiatives aim to measure global warming’s impact on high seas and deep currents

    The Southern Ocean guards its secrets well. Strong winds and punishing waves have kept all except the hardiest sailors at bay. But a new generation of robotic explorers is helping scientists to document the region’s influence on the global climate. These devices are leading a technological wave that could soon give researchers unprecedented access to oceans worldwide.

    Oceanographers are already using data from the more than 3,900 floats in the international Argo array. These automated probes periodically dive to depths of 2,000 metres, measuring temperature and salinity before resurfacing to transmit their observations to a satellite (see Diving deeper). The US$21-million Southern Ocean Carbon and Climate Observations and Modeling Project (SOCCOM) is going a step further, deploying around 200 advanced probes to monitor several indicators of seawater chemistry and biological activity in the waters around Antarctica. A primary aim is to track the prodigious amount of carbon dioxide that flows into the Southern Ocean.

    “The Southern Ocean is very important, and it’s also very poorly known because it’s just so incredibly miserable to work down there,” says Joellen Russell, an oceanographer at the University of Arizona in Tucson and leader of SOCCOM’s modelling team.

    Scientists estimate that the oceans have taken up roughly 93% of the extra heat generated by global warming, and around 26% of humanity’s CO2 emissions, but it is unclear precisely where in the seas the heat and carbon go. A better understanding of the processes involved could improve projections of future climate change.

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    SOCCOM, which launched in 2014, has funding from the US National Science Foundation to operate in the Southern Ocean for six years. Project scientists’ ultimate goal is to expand to all the world’s oceans. That would require roughly 1,000 floats, and would cost an estimated $25 million per year.

    Interest in this global array, dubbed the Biogeochemical Argo, is growing. The Japanese government has put a proposal to expand use of SOCCOM probes on the agenda for the meetings of the Group of 7 leading industrialized nations in Japan in May. And the project is gaining high-level attention as a result: the SOCCOM team has briefed John Holdren, science adviser to US President Barack Obama.

    Project scientists are rushing to develop a plan to expand use of the next-generation probes. “It’s like, ‘Oh, couldn’t they wait a year?’” jokes SOCCOM associate director Ken Johnson, an ocean chemist at the Monterey Bay Aquarium Research Institute in Moss Landing, California. His team is drafting a proposal to present to the inter­national Argo steering committee at a meeting that begins on March 22.

    Meanwhile, another set of researchers hopes to extend the existing Argo array beyond its current 2,000-metre limit. The US National Oceanic and Atmospheric Admini­stration (NOAA) is spending about $1 million annually on a Deep Argo project to monitor ocean temperature and salinity down to 6,000 metres. The agency deployed nine Deep Argo floats south of New Zealand in January, and is planning similar pilot arrays in the Indian Ocean and the North Atlantic.

    The deep-ocean data will be particularly useful in improving how models simulate ocean circulation, says Alicia Karspeck, an ocean modeller at the National Center for Atmospheric Research in Boulder, Colorado. “From a scientific perspective, it’s a no-brainer,” she says—noting that the new floats are a low-risk investment compared with spending money on developing models without additional oceanographic data.

    NOAA is using two different models of float, both designed to withstand the crushing pressures at the bottom of the sea. And Argo teams in Japan and Europe are already using upgraded floats that can reach down to 4,000 metres. The goal is to establish a new international array of some 1,250 deep-ocean floats — most of which would need to dive to 6,000 metres. Doing so would provide basic data on 99% of the world’s seawater.

    “We are really still working the bugs out of the equipment and trying to show that we can do this,” says Gregory Johnson, a NOAA oceanographer in Seattle, Washington, and one of the principal investigators for Deep Argo.

    Even if scientists succeed in expanding next-generation ocean probes around the globe, he says, the data that they provide will not supplant detailed measurements of carbon, water chemistry, salinity and temperature that are currently made by ship-based surveys. Deep Argo measures only temperature and salinity, and the technology used in Biogeochemical Argo is not yet sensitive enough to measure subtle changes in the deep ocean.

    Still, ship surveys—which are done on average every ten years—cannot follow how heat is taken up by the deep ocean. By contrast, Deep Argo would allow researchers to continually watch heat move through the oceans. That could lead to a better understanding of how the oceans respond to global warming—and how the climate responds to the oceans.

    “This has all kinds of ramifications for ecosystems and climate,” says Johnson of NOAA.

    See the full article here .

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  • richardmitnick 11:45 am on December 20, 2015 Permalink | Reply
    Tags: , , Oceanography   

    From livescience: “New X Prize Challenge: Map Ocean Floor” 

    Livescience

    December 15, 2015
    Elizabeth Palermo

    1
    Credit: Albund/Shutterstock.com

    Attention, sea-loving explorers: There’s a $7 million reason to get serious about your passion for ocean research right now.

    Yesterday (Dec. 14), Peter Diamandis, chairman and CEO of X Prize, announced the launch of the Shell Ocean Discovery X Prize, a three-year global competition that challenges researchers to build better technologies for mapping what Diamandis called one of the “greatest unexplored frontiers” — Earth’s seafloor.

    “Our oceans cover two-thirds of our planet’s surface and are a crucial global source of food, energy, economic security and even the air we breathe, yet 95 percent of the deep sea remains a mystery to us,” Diamandis said yesterday at a keynote address during the American Geophysical Union Fall Meeting in San Francisco. Right now, researchers have better maps of Mars than they do of Earth’s seafloor, he added.

    To win the Ocean Discovery X Prize, researchers will need to develop an autonomous, relatively fast-moving vehicle that can be launched from the air or shoreline. The vehicle must be equipped with technologies that allow it to create high-resolution maps of the seafloor at depths of about 13,125 feet (4,000 meters). Throughout the competition, the underwater vehicles will also be tasked with creating high-res images of individual objects, including archeological, biological or geological features of the seafloor.

    The teams that enter the competition won’t just be competing for a chance to map the world’s oceans; they’ll also be going after some significant cash prizes. The winning team will take home $4 million, and whoever comes in second place will win $1 million. Additional monetary prizes will be awarded to the top 10 teams in the competition, and the National Oceanic and Atmospheric Administration (NOAA) is offering a $1 million bonus prize to teams that demonstrate technology that uses biological and chemical signals to “sniff out” objects in the ocean.

    The NOAA portion of the prize is meant to spur the development of specific technologies that can help detect “sources of pollution, enable rapid response to leaks and spills, identify hydrothermal vents and methane seeps, as well as track marine life for scientific research and conservation efforts,” Richard Spinrad, chief scientist at NOAA, said in a statement.

    But don’t expect the winners of this competition to be announced anytime soon. The three-year contest includes a nine-month registration window and allows 12 months for the initial development of the underwater vehicles. Once the registered teams have built their vehicles, they’ll need to successfully complete two rounds of testing and judging by an expert panel before taking home any prizes.

    The Shell Ocean Discovery X Prize is just one part of the X Prize Ocean Initiative, a series of five competitions that will span a 10-year period. Millions of dollars in prizes will be awarded to those who help X Prize reach its goal of addressing critical ocean challenges by 2020. In 2011, X Prize awarded the Wendy Schmidt Oil Cleanup X Challenge prize to a manufacturing team from the United States that developed technology for quickly cleaning up oil spills. And in July 2015, the Wendy Schmidt Ocean Health X Prize was awarded to another U.S. team for its development of ocean sensors that improve scientific understanding of how carbon dioxide emissions are affecting ocean acidification.

    The first ever X Prize was awarded in 1996 to a team of researchers that built and launched a spacecraft capable of carrying three people to an altitude of 62.5 miles (100 kilometers) above Earth’s surface, twice in two weeks. Virgin Galactic — the division of the Virgin Group tasked with making commercial space travel a reality — eventually acquired the technology that won the prize.

    More information about the new Ocean Discovery X Prize can be found on the organization’s website.

    See the full article here .

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  • richardmitnick 4:54 pm on January 9, 2015 Permalink | Reply
    Tags: , , Oceanography   

    From NASA Earth: “Coloring the Sea around the Pribilof Islands” 

    NASA Earth Observatory

    NASA Earth Observatory
    Jan 9, 2015
    No Writer Credit

    1

    The Operational Land Imager (OLI) on Landsat 8 captured this view of a phytoplankton bloom near Alaska’s Pribilof Islands on September 22, 2014. The Pribilofs are surrounded by nutrient-rich waters in the Bering Sea. The milky green and light blue shading of the water indicates the presence of vast populations of microscopic phytoplankton—mostly coccolithophores, which have calcite scales that appear white in satellite images. Such phytoplankton form the foundation of a tremendously productive habitat for fish and birds.

    Blooms in the Bering Sea increase significantly in springtime, after winter ice cover retreats and nutrients and freshened water are abundant near the ocean surface. Phytoplankton populations plummet in summertime as the water warms, surface nutrients are depleted by blooms, and the plant-like organisms are depleted by grazing fish, zooplankton, and other marine life. By autumn, storms can stir nutrients back to the surface and cooler waters make better bloom conditions.

    The complicated interaction and feedback between water conditions, predators, and plankton populations was the subject of a recent paper by Mike Behrenfeld, a phytoplankton ecologist at Oregon State University. He notes that most discussions of blooms center on the physical conditions that initiate blooms. But the “dance of the plankton” is more complicated and it may involve ocean grazers—predators of phytoplankton—and other marine disturbances a bit more than previously suspected.

    Together with colleagues at four institutions, Behrenfeld has developed a “disturbance-recovery hypothesis” in which blooms tend to be started by any process that disturbs the natural balance between phytoplankton and their predators. A disturbance may involve deep mixing of the surface ocean by storms, which brings up deep ocean water along coasts (coastal upwelling). It can involve a river plume carrying extra fresh water or sediment into the ocean. Such changes affect the health and location of both the phytoplankton and the creatures that consume them. How plankton ecosystems recover from a disturbance determines how large a bloom may grow.

    “Phytoplankton are rubber-banded to their predators,” Behrenfeld said. “As long as phytoplankton are accelerating in their division rate, they’ll stay ahead. As soon as they slow down, the predators that have been increasing along with the phytoplankton will quickly catch up, stop the bloom by consuming the phytoplankton, and then begin decreasing the numbers of phytoplankton.”

    See the full article here.

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 8:29 pm on December 19, 2014 Permalink | Reply
    Tags: , , , Oceanography   

    From NSF- “Geomagnetic reversal: Understanding ancient flips and flops in Earth’s polarity” 

    nsf
    National Science Foundation

    December 19, 2014
    Ivy F. Kupec, (703) 292-8796 ikupec@nsf.gov

    Investigators
    Masako Tominaga
    Maurice Tivey
    William Sager

    Related Institutions/Organizations
    Woods Hole Oceanographic Institution

    Locations
    Western Pacific Seafloor , Hawaii

    Related Programs
    Marine Geology and Geophysics

    Imagine one day you woke up, and the North Pole was suddenly the South Pole.

    This geomagnetic reversal would cause your hiking compass to seem impossibly backwards. However, within our planet’s history, scientists know that this kind of thing actually has happened…not suddenly and not within human time scales, but the polarity of the planet has in fact reversed, which has caused scientists to wonder not only how it’s happened, but why.

    This week, as the National Science Foundation (NSF) research vessel R/V Sikuliaq continues its journey towards its home port in University of Alaska Fairbanks’ Marine Center in Seward, Alaska, she detours for approximately 35 days as researchers take advantage of her close proximity to the western Pacific Ocean’s volcanic sea floors. With the help of three types of magnetometers, they will unlock more of our planet’s geomagnetic history that has been captured in our Earth’s crust there.

    1
    Before leaving port, an undergraduate student acquires important control data with a gravitometer.

    “The geomagnetic field is one of the major physical properties of planet Earth, and it is a very dynamic property that can change from milliseconds to millions of years. It is always, always changing,” said the expedition’s chief scientist, Masako Tominaga, an NSF-funded marine geophysicist from Michigan State University. “Earth’s geomagnetic field is a shield, for example. It protects us from magnetic storms–bursts from the sun–so very pervasive cosmic rays don’t harm us. Our research will provide data to understand how changes in the geomagnetic field have occurred over time and give us very important clues to understand the planet Earth as a whole.”

    Flipping and flopping

    Reportedly, the last time, a geomagnetic reversal occurred was 780,000 years ago, known as the Brunhes-Matuyama reversal. Bernard Brunhes and Motonori Matuyama were the geophysicists who identified that reversal in 1906.

    5
    A supercomputer to model flow patterns in Earth’s liquid core.
    Dr. Gary A. GlatzmaierLos Alamos National LaboratoryU.S. Department of Energy.

    Researchers Tominaga, Maurice Tivey (from Woods Hole Oceanographic Institution) and William Sager (from University of Houston) have an interest that goes further back in history to the Jurassic period, 145-200 million years ago when a curious anomaly occurred. Scientists originally thought that during this time period, no geomagnetic reversals had happened at all. However, data–like the kind that Tominaga’s team will be collecting–revealed that in fact, the time period was full of reversals that occurred much more quickly.

    “We came to the conclusion that it was actually ‘flipping flopping,’ but so fast that it did not regain the full strength of the geomagnetic field of Earth like today’s strength. That’s why it was super, super low,” Tominaga explained. “The Jurassic period is very distinctive. We think that understanding this part of the geomagnetic field’s behavior can provide important clues for computer simulation where researchers have been trying to characterize this flipping and flopping. Our data could help predict future times when we might see this flipping flopping again.”

    Interestingly, historical records have shown points where the flipping seems likely to occur but then seems to change its mind, almost like a tease, where it returns to its original state. Those instances actually do occur on a shorter time scale than the full-fledged flipping and flopping. Again, scientists are looking for answers on why they occur as well.

    Better tools equal better data

    For approximately three decades, researchers like Tominaga have been probing this area of the western Pacific seafloor. With her cruise on R/V Sikuliaq, Tominaga and Tivey come with even more technology in hand.

    Thirty years ago, researchers didn’t have access to autonomous underwater vehicles (AUV) that could go to deeper, harder-to-reach ocean areas. However, that is just one of three ways Tominaga’s team will deploy three magnetometers during its time at sea. One magnetometer will work from aboard R/V Sikuliaq. Another will trail behind the ship, and the third will be part of the AUV.

    “The seafloor spreading at mid-ocean ridge occurred because of volcanic eruption over time. And when this molten lava formed the seafloor, it actually recorded ambient geomagnetic data. So when you go from the very young ocean seafloor right next to the mid-ocean ridge to very, very old seafloor away from the mid-ocean ridge, a magnetometer basically unveils changes in the geomagnetic field for us,” Tominaga said. “The closer we can get to the seafloor, the better the signal. That’s the rule of thumb for geophysics.”

    With the help of R/V Sikuliaq’s ship’s crew, Tominaga and Tivey, a cruise archivist who is also a computer engineer/scientist, and seven students (three of whom are undergraduates), the team will run daily operations 24 hours a day/seven days a week, deploying the magnetometers, collecting data and then moving on to the next site.

    Naturally, the weather can waylay even the best plans. “Our goal is always about the science, but the road likely will be winding,” Tominaga said. “The most enjoyable part of this work is to be able to work together with this extremely diverse group of people. The Sikuliaq crew, the folks at UAF and those connected to the ship from NSF have all been committed to seeing this research happen, which is incredibly gratifying…. When we make things happen together as a team, it is really rewarding.”

    Focus on fundamentals

    Not surprisingly, this kind of oceanographic research is among some of the most fundamental, serving as a foundation for other research where it might correlate or illuminate. Additionally, because the causes and impacts of these geomagnetic changes are unknown, connections to currents, weather patterns, and other geologic phenomenon can still be explored also.

    “NSF, along with the entire science community, has waited years for this unique state-of-the-art Arctic vessel, and the timing couldn’t be more critical,” said Rose DuFour, NSF program director. “Our hope is to use R/V Sikuliaq to help carry out the abundant arctic-based seagoing science missions that go beyond NSF-funded science and extend to those from other federal agencies, like Office of Naval Research as well.”

    Tominaga notes that another key part to the cruise’s mission is record keeping; it’s why an archivist is part of her team. He even will blog daily (with pictures). As foundational research, it’s important to “keep every single record intact,” and she believes this broadcasting daily narrative will assist in this effort. Additionally, the plan is to share the collected data as soon as possible with other researchers who can benefit from it as well. “Without going there, getting real data–providing ground truth–how do we know what is going on?” Tominaga said, explaining fieldwork’s importance.

    Tominaga is quite clear on what prompts her to keep one of the busiest fieldwork schedules, even during a season usually reserved for family and friends, sipping eggnog or champagne. “I was raised as a scientist/marine geophysicist, and I don’t just mean academically,” she said. “I really looked up to my mentors and friends and how they handed down what they know-so unselfishly. And when I was finishing my Ph.D., I realized that there will be a time I will hand down these things to the next generation. Now, as a professor at Michigan State University, I’m the one who has to pass the torch, if you will–knowledge, experience, and skills at sea. That’s what drives me.”

    See the full article here.

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    The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 “to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense…we are the funding source for approximately 24 percent of all federally supported basic research conducted by America’s colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal backing.

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  • richardmitnick 2:47 pm on December 10, 2014 Permalink | Reply
    Tags: , , , , Oceanography,   

    From astrobio.net: “Warmer Pacific Ocean could release millions of tons of seafloor methane” 

    U Washington

    University of Washington

    December 9, 2014
    Hannah Hickey

    Off the West Coast of the United States, methane gas is trapped in frozen layers below the seafloor. New research from the University of Washington shows that water at intermediate depths is warming enough to cause these carbon deposits to melt, releasing methane into the sediments and surrounding water.

    Researchers found that water off the coast of Washington is gradually warming at a depth of 500 meters, about a third of a mile down. That is the same depth where methane transforms from a solid to a gas. The research suggests that ocean warming could be triggering the release of a powerful greenhouse gas.

    b
    Sonar image of bubbles rising from the seafloor off the Washington coast. The base of the column is 1/3 of a mile (515 meters) deep and the top of the plume is at 1/10 of a mile (180 meters) deep.Brendan Philip / UW

    “We calculate that methane equivalent in volume to the Deepwater Horizon oil spill is released every year off the Washington coast,” said Evan Solomon, a UW assistant professor of oceanography. He is co-author of a paper to appear in Geophysical Research Letters.

    While scientists believe that global warming will release methane from gas hydrates worldwide, most of the current focus has been on deposits in the Arctic. This paper estimates that from 1970 to 2013, some 4 million metric tons of methane has been released from hydrate decomposition off Washington. That’s an amount each year equal to the methane from natural gas released in the 2010 Deepwater Horizon blowout off the coast of Louisiana, and 500 times the rate at which methane is naturally released from the seafloor.

    Dissociation of Cascadia margin gas hydrates in response to contemporary ocean warming
    Geophysical Research Letters | Dec. 5, 2014

    “Methane hydrates are a very large and fragile reservoir of carbon that can be released if temperatures change,” Solomon said. “I was skeptical at first, but when we looked at the amounts, it’s significant.”

    Methane is the main component of natural gas. At cold temperatures and high ocean pressure, it combines with water into a crystal called methane hydrate. The Pacific Northwest has unusually large deposits of methane hydrates because of its biologically productive waters and strong geologic activity. But coastlines around the world hold deposits that could be similarly vulnerable to warming.

    “This is one of the first studies to look at the lower-latitude margin,” Solomon said. “We’re showing that intermediate-depth warming could be enhancing methane release.”
    map of Washington coast

    The yellow dots show all the ocean temperature measurements off the Washington coast from 1970 to 2013. The green triangles are places where scientists and fishermen have seen columns of bubbles. The stars are where the UW researchers took more measurements to check whether the plumes are due to warming water.Una Miller / UW

    Co-author
    Una Miller, a UW oceanography undergraduate, first collected thousands of historic temperature measurements in a region off the Washington coast as part of a separate research project in the lab of co-author Paul Johnson, a UW professor of oceanography. The data revealed the unexpected sub-surface ocean warming signal.

    “Even though the data was raw and pretty messy, we could see a trend,” Miller said. “It just popped out.”

    The four decades of data show deeper water has, perhaps surprisingly, been warming the most due to climate change.

    “A lot of the earlier studies focused on the surface because most of the data is there,” said co-author Susan Hautala, a UW associate professor of oceanography. “This depth turns out to be a sweet spot for detecting this trend.” The reason, she added, is that it lies below water nearer the surface that is influenced by long-term atmospheric cycles.

    The warming water probably comes from the Sea of Okhotsk, between Russia and Japan, where surface water becomes very dense and then spreads east across the Pacific. The Sea of Okhotsk is known to have warmed over the past 50 years, and other studies have shown that the water takes a decade or two to cross the Pacific and reach the Washington coast.

    s
    Map of the Sea of Okhotsk

    “We began the collaboration when we realized this is also the most sensitive depth for methane hydrate deposits,” Hautala said. She believes the same ocean currents could be warming intermediate-depth waters from Northern California to Alaska, where frozen methane deposits are also known to exist.

    m
    The yellow dots show all the ocean temperature measurements off the Washington coast from 1970 to 2013. The green triangles are places where scientists and fishermen have seen columns of bubbles. The stars are where the UW researchers took more measurements to check whether the plumes are due to warming water.Una Miller / UW

    m
    Researchers used a coring machine to gather samples of sediment off Washington’s coast to see if observations match their calculations for warming-induced methane release. The photo was taken in October aboard the UW’s Thomas G. Thompson research vessel.Robert Cannata / UW

    Warming water causes the frozen edge of methane hydrate to move into deeper water. On land, as the air temperature warms on a frozen hillside, the snowline moves uphill. In a warming ocean, the boundary between frozen and gaseous methane would move deeper and farther offshore. Calculations in the paper show that since 1970 the Washington boundary has moved about 1 kilometer – a little more than a half-mile – farther offshore. By 2100, the boundary for solid methane would move another 1 to 3 kilometers out to sea.

    Estimates for the future amount of gas released from hydrate dissociation this century are as high as 0.4 million metric tons per year off the Washington coast, or about quadruple the amount of methane from the Deepwater Horizon blowout each year.

    Still unknown is where any released methane gas would end up. It could be consumed by bacteria in the seafloor sediment or in the water, where it could cause seawater in that area to become more acidic and oxygen-deprived. Some methane might also rise to the surface, where it would release into the atmosphere as a greenhouse gas, compounding the effects of climate change.
    researchers on ship

    2
    Evan Solomon (right) and Marta Torres (left, OSU) aboard the UW’s Thomas G. Thompson research vessel in October, with fluid samples from the seafloor that will help answer whether the columns of methane bubbles are due to ocean warming.Robert Cannata / UW

    Researchers now hope to verify the calculations with new measurements. For the past few years, curious fishermen have sent UW oceanographers sonar images showing mysterious columns of bubbles. Solomon and Johnson just returned from a cruise to check out some of those sites at depths where Solomon believes they could be caused by warming water.

    “Those images the fishermen sent were 100 percent accurate,” Johnson said. “Without them we would have been shooting in the dark.”

    Johnson and Solomon are analyzing data from that cruise to pinpoint what’s triggering this seepage, and the fate of any released methane. The recent sightings of methane bubbles rising to the sea surface, the authors note, suggests that at least some of the seafloor gas may reach the surface and vent to the atmosphere.

    The research was funded by the National Science Foundation and the U.S. Department of Energy. The other co-author is Robert Harris at Oregon State University.

    See the full article here.

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    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.

    So what defines us — the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 7:55 am on November 11, 2014 Permalink | Reply
    Tags: , , , Oceanography   

    From livescience: “Robot Gliders See How Antarctic Ice Melts From Below” 

    Livescience

    November 10, 2014
    Becky Oskin

    Scientists suspect Antarctica’s shrinking glaciers are melting from the bottom up, and a fleet of robot ocean gliders may help explain why.

    Beneath the icy Weddell Sea in West Antarctica, the gliders discovered turbulent warm currents near ice shelves, the huge floating platforms where continental glaciers extend icy tongues into the sea. The swirling eddies carry pulses of warm water to the shallow depths underneath the ice, scientists report today (Nov. 10) in the journal Nature Geoscience.

    boat
    The research ship James Clark Ross in the Weddell Sea, January 2012.
    Credit: Andrew Thompson/Caltech

    “What we’re looking at is delivery of heat right up to the ice shelf, where the ocean touches up against the ice,” said lead study author Andrew Thompson, a physical oceanographer at Caltech. “It’s almost like a blob of warm water, a little ocean storm.” [Album: Stunning Photos of Antarctic Ice]

    Previous work already pointed to warm water — rather than hotter air temperatures — as the reason for Antarctica’s retreating ice shelves. (The disappearing ice is part of the continental ice sheet, not the sea ice that freezes and melts each year.) But to confirm these suspicions, the researchers needed to get under the ice to see how the process works.

    In 2012, Thompson and colleagues from the University of East Anglia, in the United Kingdom, used remotely operated gliders to probe the ocean conditions near ice shelves in the Weddell Sea. The gliders rise and sink without propellers, relying instead on a battery-driven pump that changes their buoyancy via a fluid-filled bladder. Every few hours, the six-foot-long (1.8 meters) glider surfaces and uploads its data via a satellite phone network. The gliders collected temperature and salinity data for two months, exploring the upper 0.6 miles (1 kilometer) of the ocean.

    When the gliders hit an eddy, the sleek yellow robots were often caught up in the powerful vortices. “You could almost know by where it came up that it had hit this anomalous region,” Thompson told Live Science. “The glider would go down and end up in a quite different place.”

    shelf
    An illustration showing how warm ocean currents circulate beneath Antarctica’s floating ice shelves. The continental shelf and slope are brown and the glacier is white.
    Credit: Andrew Thompson/Caltech and Lance Hayashida/Caltech Marketing & Communications

    The findings are the first to explain how warm water rises from deeper levels to reach the floating ice shelves. The results suggest the stormlike currents bring up pulses of warm water, which flow under the ice at irregular intervals. Now, researchers need to find out what happens when this heat reaches the grounding line, the spot where glaciers transfer their weight from the continent to the ocean. This is where most of the melting takes place, Thompson said.

    “What we’re seeing from the gliders is that it’s not a steady circulation in and out,” Thompson said. “This is really the first step of understanding of what heat goes in, and how efficient that heat is in melting the ice shelves.”

    Alternating layers of cold and warm water surround Antarctica, and it only takes a few degrees of difference to dissolve a glacier. The warmer water is typically in the middle layer of the ocean. It arrives from the north, delivered on a giant current called the global conveyor belt. Colder water lies on the surface, often formed when cold wind blows over the ocean and sea ice freezes up. Dense, cold water is also on the ocean bottom.

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  • richardmitnick 9:31 am on October 3, 2014 Permalink | Reply
    Tags: , , Oceanography   

    From NSF: “New map uncovers thousands of unseen seamounts on ocean floor” 

    nsf
    National Science Foundation

    October 2, 2014
    Media Contacts
    Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov
    Mario Aguilera, SIO, (858) 534-3624, maguilera@ucsd.edu

    Scientists have created a new map of the world’s seafloor, offering a more vivid picture of the structures that make up the deepest, least-explored parts of the ocean.

    The feat was accomplished by accessing two untapped streams of satellite data.

    Thousands of previously uncharted mountains rising from the seafloor, called seamounts, have emerged through the map, along with new clues about the formation of the continents.

    Combined with existing data and improved remote sensing instruments, the map, described today in the journal Science, gives scientists new tools to investigate ocean spreading centers and little-studied remote ocean basins.

    Earthquakes were also mapped. In addition, the researchers discovered that seamounts and earthquakes are often linked. Most seamounts were once active volcanoes, and so are usually found near tectonically active plate boundaries, mid-ocean ridges and subducting zones.

    The new map is twice as accurate as the previous version produced nearly 20 years ago, say the researchers, who are affiliated with California’s Scripps Institution of Oceanography (SIO) and other institutions.

    “The team has developed and proved a powerful new tool for high-resolution exploration of regional seafloor structure and geophysical processes,” says Don Rice, program director in the National Science Foundation’s Division of Ocean Sciences, which funded the research.

    “This capability will allow us to revisit unsolved questions and to pinpoint where to focus future exploratory work.”

    Developed using a scientific model that captures gravity measurements of the ocean seafloor, the map extracts data from the European Space Agency’s (ESA) CryoSat-2 satellite.

    cryo2
    ESA Cryosat-2

    CryoSat-2 primarily captures polar ice data but also operates continuously over the oceans. Data also came from Jason-1, NASA’s satellite that was redirected to map gravity fields during the last year of its 12-year mission.

    j1
    NASA/Jason-1

    “The kinds of things you can see very clearly are the abyssal hills, the most common landform on the planet,” says David Sandwell, lead author of the paper and a geophysicist at SIO.

    The paper’s co-authors say that the map provides a window into the tectonics of the deep oceans.

    The map also provides a foundation for the upcoming new version of Google’s ocean maps; it will fill large voids between shipboard depth profiles.

    Previously unseen features include newly exposed continental connections across South America and Africa and new evidence for seafloor spreading ridges in the Gulf of Mexico. The ridges were active 150 million years ago and are now buried by mile-thick layers of sediment.

    “One of the most important uses will be to improve the estimates of seafloor depth in the 80 percent of the oceans that remain uncharted or [where the sea floor] is buried beneath thick sediment,” the authors state.

    Co-authors of the paper include R. Dietmar Muller of the University of Sydney, Walter Smith of the NOAA Laboratory for Satellite Altimetry Emmanuel Garcia of SIO and Richard Francis of ESA.

    The study also was supported by the U.S. Office of Naval Research, the National Geospatial-Intelligence Agency and ConocoPhillips.

    See the full article here.

    The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 “to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense…we are the funding source for approximately 24 percent of all federally supported basic research conducted by America’s colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal backing.

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