Seal Takes Ocean Heat Transport Data to New Depths

From NASA

By Esprit Smith,
NASA’s Earth Science News Team

A tagged elephant seal basks on Kerguelen Island, a French territory in the Antarctic. Elephant seals are tagged as part of a French research program called SO-MEMO (Observing System - Mammals as Samplers of the Ocean Environment), operated by the French National Center for Scientific Research (CNRS). The tags - actually, sensors with antennas - are glued to the seals' heads in accordance with established ethical standards when the animals come ashore either to breed or to molt. The researchers remove the tags to retrieve their data when the seals return to land. If they miss a tag, it drops off with the dead skin in the next molting season. Credit: Sorbonne University/Etienne Pauthenet › Larger view

A tagged elephant seal basks on Kerguelen Island, a French territory in the Antarctic. Elephant seals are tagged as part of a French research program called SO-MEMO (Observing System – Mammals as Samplers of the Ocean Environment), operated by the French National Center for Scientific Research (CNRS). The tags – actually, sensors with antennas – are glued to the seals’ heads in accordance with established ethical standards when the animals come ashore either to breed or to molt. The researchers remove the tags to retrieve their data when the seals return to land. If they miss a tag, it drops off with the dead skin in the next molting season. Credit: Sorbonne University/Etienne Pauthenet › Larger view

The Antarctic Circumpolar Current flows in a loop around Antarctica, connecting the Atlantic, Pacific and Indian oceans. It is one of the most significant ocean currents in our climate system because it facilitates the exchange of heat and other properties among the oceans it links.

But how the current transfers heat, particularly vertically from the top layer of the ocean to the bottom layers and vice versa, is still not fully understood. This current is very turbulent, producing eddies — swirling vortices of water similar to storms in the atmosphere — between 30 to 125 miles (50 to 200 kilometers) in diameter. It also spans some 13,000 miles (21,000 kilometers) through an especially remote and inhospitable part of the world, making it one of the most difficult currents for scientists — as least those of the human variety — to observe and measure.

Luckily for Lia Siegelman, a visiting scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, the rough seas posed no challenge for her scientific sidekick: a tagged southern elephant seal.

Equipped with a specialized sensor reminiscent of a small hat, the seal swam more than 3,000 miles (4,800 kilometers) on a three-month voyage, much of it through the turbulent, eddy-rich waters of the Antarctic Circumpolar Current. The seal made around 80 dives at depths ranging from 550 to 1,090 yards (500 to 1,000 meters) per day during this time. All the while, it collected a continuous stream of data that has provided new insight into how heat moves vertically between ocean layers in this volatile region — insight that brings us one step closer to understanding how much heat from the Sun the ocean there is able to absorb.

3D schematic of how elephant seals collect data This 3D schematic shows how a tagged elephant seal collects data by swimming long distances and diving to great depths through turbulent waters near Antarctica. Satellite data are used to identify characteristics of the waters through which the seals swim. The blue represents cold, dense water; the red areas are less dense and typically warmer. Credit: Tandi Reason Dahl › Larger view

For a new paper published recently in Nature Geoscience, Siegelman and her co-authors combined the seal’s data with satellite altimetry data. The satellite data of the ocean surface showed where the swirling eddies were within the current and which eddies the seal was swimming through. Analyzing the combined dataset, the scientists paid particular attention to the role smaller ocean features played in vertical heat transport. Siegelman was surprised by the results.

“These medium-sized eddies are known to drive the production of small-scale fronts — sudden changes in water density similar to cold and warm fronts in the atmosphere,” she said. “We found that these fronts were evident some 500 meters [550 yards] into the ocean interior, not just in the surface layer like many studies suggest, and that they played an active role in vertical heat transport.”

According to Siegelman, their analysis showed that these fronts act like ducts that carry a lot of heat from the ocean interior back to the surface. “Most current modeling studies indicate that the heat would move from the surface to the ocean interior in these cases, but with the new observational data provided by the seal, we found that that’s not the case,” she said.

Why It Matters

The ocean surface layer can absorb only a finite amount of heat before natural processes, like evaporation and precipitation, kick in to cool it down. When deep ocean fronts send heat to the surface, that heat warms the surface layer and pushes it closer to its heat threshold. So essentially, in the areas where this dynamic is present, the ocean isn’t able to absorb as much heat from the Sun as it otherwise could.

Current climate models and those used to estimate Earth’s heat budget don’t factor in the effects of these small-scale ocean fronts, but the paper’s authors argue that they should.

“Inaccurate representation of these small-scale fronts could considerably underestimate the amount of heat transferred from the ocean interior back to the surface and, as a consequence, potentially overestimate the amount of heat the ocean can absorb,” Siegelman said. “This could be an important implication for our climate and the ocean’s role in offsetting the effects of global warming by absorbing most of the heat.”

The scientists say this phenomenon is also likely present in other turbulent areas of the ocean where eddies are common, including the Gulf Stream in the Atlantic Ocean and the Kuroshio Extension in the North Pacific Ocean.

Although their results are significant, Siegelman says more research is needed to fully understand and quantify the long-term effects these fronts may have on the global ocean and our climate system. For example, the study is based on observations in the late spring and early summer. Results may be more pronounced during winter months, when these small-scale fronts tend to be stronger. This body of research will also benefit from additional studies in other locations.

For more information on how the elephant seal data were acquired, see:

https://climate.nasa.gov/news/2871/data-with-flippers-studying-the-ocean-from-a-seals-point-of-view/

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58 thoughts on “Seal Takes Ocean Heat Transport Data to New Depths

  1. ” The seal made around 80 dives at depths ranging from 550 to 1,090 yards (500 to 1,000 meters) per day during this time.”

    Wow. We have these fancy things called Argo floats… they do it without supergluing stuff to seals.
    And they go down to 2000 meters. They do that multiple times in day… as there is no point in that for temp data of the same geographic spot.

    I mean its fine to use use these things to study seal and their hunting habits. But if the point is ocean and temperature stuff? Let’s just use robots like Argo.

      • The seals are not cool, they are warm (mammals you know). Are we then measuring a Mammal Heat Island, just like the Urban Heat variant? LOL

        • oebele bruinsma … at 12:04 am
          …Are we then measuring a Mammal Heat Island, just like the Urban Heat variant? LOL

          Ha ha ha ha ha ha ha ha ha ha!

          First chuckle of the day.

          • Perhaps what is needed is a study to determine just how much CO2 a Climate Scientist is exposed to and how that level affects their environment and ability for critical thinking.
            We need to GLUE sensors for CO2 and Temperature directly to the foreheads of Climate Scientists and monitor their direct surroundings for a period of 1 year to see if the gradually increasing CO2 levels has a negative affect on their thought process.

        • Besides that, I’m guessing that the seal probably provides a biased sample by preferring certain temperature ranges where it knows the food source is more abundant.

          But in a larger sense, we all know exactly what this so called “Climate Study” is going to find. Let’s see if I can accurately predict the headline: “…Worse than previously thought…”

    • Agreed Joel.
      This quote, however, also highlights another facet of the AGW issue – ie how wildlife in the real world (for another example think altitude and latitude changes for migrating birds) manages to cope with temperature changes many times what supposedly has happened over the last 150 years, all within a few hours or days, and all by choice. It surely flattens the argument that a 1C change in 150 years, followed possibly by another 0.5C over the next 30 years (or whatever story you like to follow) is going to cause some kind of mass extinction event for humans and animals. In the context of what these seals experience, such thinking is hard to fathom….

      • The seals deal with +/- 15ºC (4º C to 19ºC) changes in water temp with their dives and migrations with aplomb.
        Does anyone honestly think 0.5ºC changes at patch of ocean, a change which is lost in seasonal variations and annual swings, matters to the seals or their food?

        After 3 million years of Earth glacial cycles, these marine mammals and their food (fish) exist exactly because they adaptable to changing conditions, not because they can’t. Just like us humans did leaving the Savannah of Africa 300Kyr ago to conquer the globe from hot climate extreme to arctic climate extreme.

    • Joel,

      Argo floats don’t swim. They go with the flow – therefore they never sample a cross section of an eddy, and they never cross front bondaries. Whereas, seals carry their thermal inertia into cold water to catch animals which live in the cold. Therefore they actively seek out fronts and charge backwards and forward through them.

      A totally different view to the argo floats and one that compliments them.

      Jay

      • Fish schoolings, the seals’ food source, are using many millions of years of evolved senses to find deep water upwellings where krill and phytoplanton feed, not stagnant gyres and eddies where the phytoplankton is depleted.

        With an Argo float twirling around in an eddy weeks on-end, it reports its geographical location with each surface transmission using its GPS coordinates. Researchers can see gyres and eddies with both multi-spectral satellite photos and the Argo positions superimposed.
        With a swimming mammal hunting fish schools, the eddies are likely avoided or swam through as they would quickly become depleted of food.
        Use the super-glued sensors to study seals and their hunting feeding habits… fine. That is awesome science.
        But to use them to study temperature and climate change in the oceans??? I have a whole lot problems with that. But I understand why the seal biologists claim to do that. Climate rent seeking is where that next grant money resides in grant-limited funding environment.

    • Given that the average ocean depth is of the order of 5,000 metres, the data collected by seals and the Argot doohickeys should be kept in perspective.

      • hi Barcoo – your figure seems to be for the Pacific Ocean. Average total ocean depth is about 3 700m.
        cheers edi

  2. Why not glue a transponder to the heads of these people and let’s monitor what they do … who knows, they may lead us directly to the hidden data cache !

  3. Models, uh huh? Computer models with variable constants. But what would I know I am not a computer modeller.

  4. “This could be an important implication for our climate and the ocean’s role in offsetting the effects of global warming by absorbing most of the heat.”

    So now, according to these “scientists”, a warmer body B1 – the oceans – can absorp heat of a cooler body B2 – the atmosphere – and thus offset B2’s global warming … Again the “hiden heat in the oceans” scam resurfaces thanks to a bunch of clowns abusing wildlife to spout out they junk science.

    “Siegelman says more research is needed to fully understand and bla bla bla …”

    And of course, they need cash for that … Quelle surprise !

    • If heat apparently won’t readily enter the ocean from above, but instead is observed to emerge out of its surface, then its major sourcing is neither solar nor atmospheric but terrestrial. Thus we shouldn’t overlook the revealed tectonic plate boundary, volcanic, and hydrothermal vent concentrations of abyssal sourced ocean heat from the lithospheric crust and underlying hot planetary mantle that deliver such energy for dispersal upward into ocean waters.

      • Indeed.
        https://sp.lyellcollection.org/content/461/1/231
        “In other major rift systems of the world, rift interiors with thin, stretched crust are associated with considerable volcanism . However, …. the ice cover has deterred a comprehensive identification of the full spread of volcanoes throughout the West Antarctic Rift System.”
        Anyone who says the science is settled clearly has no idea what they are talking about.

      • “If heat apparently won’t readily enter the ocean from above, but instead is observed to emerge out of its surface, then its major sourcing is neither solar nor atmospheric but terrestrial.”

        Certainly not. The oceans absorb the vast majority of solar energy. Water has a very low albedo and visible light penetrates to a depth of many meters before it is completely absorbed, so a fairly thick layer is heated by the sun. Geothermal energy is very small in comparison, though probably of some importance for abyssal waters (which however stay very cold).

  5. Is no one worrying about those poor seals pictured on land without a bit of ice in sight? Don’t try telling me this is normal – I know it has to be climate change! /sarc.

  6. Warm water can absorb less heat from the sun before evaporation kicks in and heat is moved upward in the atmosphere where it eventually radiates to outer space.

    The seal study was done in relatively cold water where evaporation isn’t as big a deal as it is at the equator where the effect would be much greater. It seems reasonable to think that an El Nino actually reduces the heat absorbed at the planet’s surface.

  7. It isn’t April 1st by any chance, is it? Hat wearing seals???? Someone will tell us you can buy those in ARGO’s.

  8. ““Most current modeling studies indicate that the heat would move from the surface to the ocean interior in these cases, but with the new observational data provided by the seal, we found that that’s not the case,” she said.”

    OMG!! The models are wrong? How could that be, the science is unsettled, again…….

  9. Attaching a thermometer to a seal’s head might be able to track temperature differences in the water through which the seal swims, but it should not be used to track absolute temperatures to attempt to follow changes in ocean temperature with time. The seal’s own body heat might warm up the surrounding water by a few thousandths of a degree, which would throw off the calculated heat balance of the ocean.

    And as Steve Case and Scissor have pointed out above, a wild seal will swim wherever its food supply is most abundant, which probably varies seasonally, and probably follows the movement of fish or other prey. Temperature data from a seal will not give a true spatial or temporal distribution, but only show temperatures from wherever the seal prefers to be at a given time. Although a seal may be able to dive to 500 meters deep, if the food supply is near the surface, a seal will prefer to stay closer to the surface in order to reduce the time between breaths.

    It would be interesting to repeat this experiment with many seals, which may give a more meaningful spatial profile, unless all the seals tend to stay close to one another.

  10. Submariners have been finding out about these “fronts” for decades, perhaps they might be able to help the Sarbonne with some extra data.
    Maybe the sensors might even be stuck to the outside of the submarines.
    Or would that be too simple?

  11. “All the while, it collected a continuous stream of data that has provided new insight into how heat moves vertically between ocean layers in this volatile region”

    Odd.
    Seals swim at multiple speeds through the water column.
    If they’re chasing prey, they dive faster.
    If they’re searching for prey, they dive slower.
    If they’re playing, they dive at multiple speeds, haphazardly.

    Then there is the thermistor. Just how rapidly does the thermistor attached to that poor seal’s head register temperature? Even the alleged “instant” thermistors take several seconds.

    How do these researchers account for a seal’s rate of speed and a lag in registered temperatures?
    How do these researchers account for a seal following prey that are themselves following specific water temperatures?

    Currently, it sounds more funds wasted by NOAA on stovepipe confirmation bias research.

  12. ““Most current modeling studies indicate that the heat would move from the surface to the ocean interior in these cases, but with the new observational data provided by the seal, we found that that’s not the case,” she said.”

    Surprise, suprise- there is a significant ocean heat transport that is not include in the models.
    What other factors have not been included?
    Why do the models assume that the only real effects are human caused?

    Because that is what they were directed to do by the UN and its IPCC. The main climate model assumption is that only human-caused warming matters.

    Obviously a tremendous FAIL.

  13. This research reads like a joke. The surface of the Southern Ocean is generally only a few degrees above freezing, and the atmosphere above it is not much warmer.

    Not only that, but the solar energy available enters the ocean at very low angles, & doesn’t generate much heat when it does. If it did the Southern Ocean and the atmosphere above it would be a lot warmer than they are.

    So the researchers find that in and around these big eddies, warmer water is being moved up to the surface, not the other way round as is usually presumed.

    From that discovery, they slide into conjecture of the “it’s worse than we thought” variety. They postulate that climate models are programmed with a certain level of heat that the global oceans are able to absorb, but with their new discovery, that level is too high, and the models are actually overestimating how much heat from the atmosphere can be absorbed. Ergo, they are underestimating the future rate of global warming, and we are all gonna fry sooner than we thought.

  14. Deep oceans are not warm. Heat rises (even in the ocean). If you go below about 400 feet (or so) the water is cold and gets colder the deeper you go. This applies to every ocean in the world, and I have been deeper than 400 feet in every ocean (and many seas) except the Arctic Ocean. US Navy submarine service, 24 years, Submarine Sonar Technician (NEC St-0416).

    • Yes, but eddies are akin to whirlpools and can bring higher temperature surface water to lower depths. As the graph shows, to the tune of thousands of feet.

      Their conclusions suggests that there may not be as much missing heat as Dr. Trenberth has suggested.

      Yes, the boats do record temp, but there is that whole issue of placing a geographic location to the recording of those temps that may be a sticking point.

      I remember looking over the logs to see the temps going up and down every x hours.
      Big circles.
      Very big circles.

      The boats also make you appreciate the sunlight…

  15. From the article: “The Antarctic Circumpolar Current flows in a loop around Antarctica, connecting the Atlantic, Pacific and Indian oceans. It is one of the most significant ocean currents in our climate system because it facilitates the exchange of heat and other properties among the oceans it links.”

    So can we say the Antarctic Circumpolar Current is the oceanic equivalent of an atmospheric jet stream?

    Those cyclones at the poles of Jupiter and Saturn are doing the same thing as these ocean “fronts”, they are moving heat from the interior to the exterior.

    I imagine we will someday have underwater weather maps of Earth as detailed as our atmospheric weather maps. A very interesting subject.

    • “It is one of the most significant ocean currents in our climate system because it facilitates the exchange of heat and other properties among the oceans it links”

      They forgot to mention that it also very efficiently prevents movement of heat from lower latitudes to Antarctica. Antarctica froze over when the circumpolar ocean opened up 35 million years ago.

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