Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere

Paper at Geophysical Research Letters.

First published: 15 July 2019
Abstract and Introduction~ctm


As Arctic temperatures rise at twice the global rate, sea ice is diminishing more quickly than models can predict. Processes that dictate Arctic cloud formation and impacts on the atmospheric energy budget are poorly understood, yet crucial for evaluating the rapidly changing Arctic. In parallel, warmer temperatures afford conditions favorable for productivity of microorganisms that can effectively serve as ice nucleating particles (INPs). Yet the sources of marine biologically derived INPs remain largely unknown due to limited observations. Here we show, for the first time, how biologically derived INPs were likely transported hundreds of kilometers from deep Bering Strait waters and upwelled to the Arctic Ocean surface to become airborne, a process dependent upon a summertime phytoplankton bloom, bacterial respiration, ocean dynamics, and wind‐driven mixing. Given projected enhancement in marine productivity, combined oceanic and atmospheric transport mechanisms may play a crucial role in provision of INPs from blooms to the Arctic atmosphere.

1 Introduction

Arctic mixed‐phase clouds (AMPCs) are a key component of the Arctic climate system that affect the delicate energy balance over frozen surfaces (Morrison et al., 2012). One of the least understood processes regarding AMPCs is aerosol‐cloud interactions, specifically those pertaining to cloud ice formation by mineral or biological ice nucleating particles (INPs; Solomon et al., 2018). Biologically derived INPs (Bio‐INPs; INPs including microbes and their exudates) that form ice greater than −15 °C are typically thought to be of terrestrial origin—yet marine bio‐INPs have been shown to form ice at temperatures up to −3 °C (McCluskey et al., 2018a; DeMott et al., 2016; Irish et al., 2017; Irish et al., 2019; Schnell, 1975). AMPC temperatures are often greater than −10 °C on average, are most prevalent in late summer, and can exist down to the surface (Shupe, 2011; Shupe et al., 2006, 2011), while the cloud‐driven mixed layer can also extend down to the surface (Shupe et al., 2013). These statistics indicate that marine bio‐INPs could play a critical role in cloud formation, especially in the summer when emitted from open water (Wex et al., 2019). Yet field observations of such INPs are exceedingly rare and are mainly reported in midlatitude or Southern Ocean regions (Bigg, 1973; Schnell, 1977).

Measurements of INPs in both the ocean and atmosphere are essential to directly link the thriving marine sources of primary productivity (production of organic matter by phytoplankton) to the clouds above. Schnell (1977) measured INPs in sub‐Arctic seawater and air and found cases where atmospheric INPs were comparable or much lower in abundance than those found in the seawater, indicating the ocean was likely the source of the atmospheric INPs. The Arctic summer possesses quintessential conditions for proliferation of primary productivity when open water and daylight hours are at their maxima (Moore et al., 2018). In a recent study, Gabric et al. (2018) demonstrate a clear connection between sea ice extent, productivity, and marine biogenic aerosols. Additionally, recent modeling work has demonstrated that marine organic aerosols lead to increases in cloud ice in polar regions during the summer (Huang et al., 2018). However, to date no studies have reported INP enhancements from naturally occurring phytoplankton blooms, which can link such sources to the air above. We present results from a summertime expedition in the Bering and Chukchi Seas demonstrating how bio‐INPs likely from a phytoplankton bloom became airborne in the lower Arctic atmosphere.

Here is the conclusion. ~ctm

4 Conclusions and Broader Implications

Our results demonstrate that flow dynamics and mixing, in the presence of wind forcing, can strongly impact INP populations from the bottom of the shelf to the air above the surface (Figure 4). Nutrient‐rich AW flows into Bering Strait, enabling proliferation of a phytoplankton bloom in the surface waters. The photo‐inhibited bacteria residing in and near the sediment below the bloom are dormant and unproductive since vertical export is limited by the rapid lateral transport and food is not available to them. As the flow progresses northward and slows, the nutrients are drawn down, and the phytoplankton starts to decay and sink, providing a steady source of carbon to the seafloor. Bacterial respiration and growth ensue at the deposition zone north of Bering Strait. At this point, northerly wind forcing results in the transport of the active bacteria from the bottom deposition zone to the surface via two mechanisms: upwelling on the cyclonic side of the reversed circulation and turbulent wind mixing. The strong winds also likely induced surface bubble breaking and aerosolization of the bacterial material. Some of these materials were likely proficient INPs that may assist cloud glaciation processes at relatively warm temperatures should they become vertically mixed through the marine boundary layer to cloud levels. Shupe et al. (2006, 2013) report relatively low and warm summertime AMPCs and occasional vertical mixing in the Arctic marine boundary layer, which makes it plausible that the characteristic INPs studied here may reach levels in which they realistically assist cloud glaciation. However, we note that our findings are qualitative in nature and a more quantitative assessment of the relationships between the various measurements should be conducted in future studies.


Figure 4

Open in figure viewerPowerPoint

Conceptual model of processes associated with the bloom. Bottom axis represents relative distance and time. Numbers correspond to the steps in the process, namely, (1) nutrient input, (2) primary production, (3) slowing of the current, (4) deposition of nutrient exhaustion, (5) wind‐forced turnover, and (6) aerosolization. The blue with the minus sign indicates inactive microbes, while the green with the plus sign indicates actively producing microbes. Blue and white arrows indicate water and air movement, respectively. DBO3 = Distributed Biological Observatory transect 3.

More broadly, the processes that invigorate AMPC formation are poorly quantified, but results such as ours can help elucidate the sources, abundance, and efficiency of Arctic INPs in addition to the mechanisms that promote aerosolization from the marine environment. One thought‐provoking question that arises from this study is as follows: Are shelf deposition zones in the Arctic a key source of airborne INPs? We believe that this question warrants further study, especially considering the ongoing ecological shifts in this region, and potentially other regions, rich in benthic and pelagic activity. Additionally, with the projected increase in Arctic blooms under warmer climate scenarios, quantifying INP abundance and effectiveness from such sources with similar particulate dispersal processes as those reported here is crucial to estimating the Arctic INP and ultimately the Arctic aerosol budget. Another question that should be addressed in future observations is as follows: Will a warmer climate, and thus a more productive Arctic Ocean, serve as a dominant source of INPs that affect AMPC formation? Results from the current work provides motivation to augment the frequency and spatial coverage of targeted Arctic INP, ecological, and oceanographic measurements in the future.

Full paper here.


55 thoughts on “Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere

  1. The thing with Sea Ice is that the Summer minimum really doesn’t matter, it freezes again through Winter. If the maximum was reducing heavily I might get concerned, generally the ice melts and refreezes.

    • Except the summer minimum is getting lower and the winter maximum is also lower; the thickness is lower, the volume is lower and there is less multi year ice.

      Currently extent is at second lowest for the satellite record, likely to finish 3rd after 2016 (or even second). It is in a terrible state… not recovering, still declining.

      This one set of facts completely blows any skeptic argument out of the water.

      • It looks like arctic temperatures are almost as warm today as they were back in the 1930’s. See the link below.

        There was a lot of ice melting in the 1930’s, too.

        After the high temperatures of the 1930’s, the climate cooled down to the point that in the 1970’s climate scientists were wringing their hands over fears the Earth was entering another ice age. Then the weather warmed up again to the point that today we are almost as warm as in the 1930’s. And since we hit the most recent highpoint in temperatures in Feb. 2016, the Earth has cooled by about 0.5C.

        So will we continue to cool as we did after the 1930’s highpoint and after the 1998 highpoint, or will we continue to warm and break the old records of the 1930’s, 1998, and 2016? Perhaps in a few decades climate scientists will again be worrying about a new Ice Age. Anyway, right now, the globe is cooling.

      • And here’s another chart for you, Griff, showing how there is more arctic sea ice today than there was back in the hot 1930’s.

        See how starting the chart in 1979 distorts the picture of arctic sea ice? Taking a longer view shows there is nothing extraordinary going on today in the arctic. It’s warm and the ice is melting. It was warmer in the past, and more ice melted then than now. Relax, there is no need to worry.

      • Griff

        I am not sure what “skeptic argument” you are blowing out of the water. Perhaps you can clarify that for us.

        The world does not need summer sea ice to survive. Not very long ago the Arctic Ocean was probably ice-free in summer.

        Declining summer sea ice is a good thing. The Arctic Ocean is much more productive when it is warmer: more phytoplankton, more krill (etc), more fish, more seals, more polar bears and so on.

        I see it as an unfortunate sign that the total ice volume and average thickness have been rising since 2012. As the Earth enters a prolonged multi-year cooling period the negative impacts will be visible across the Northern Hemisphere.

        If the global average temperature was strongly influenced by AG CO2 emissions, there would be no cooling. None, but that is not what is observed. Sea ice coverage, thickness and volume would monotonically reduce. They don’t. That indicates natural variation, which must first be quantified before assigning some fraction of any warming to CO2 changes.

        Let’s check back in two years to see how the trend looks. If the 2012-2021 trend is up, we will have an indication that the descent into the next glaciation continues.

      • Except that currently, extent decline is stalled, and rate of decline over the last few weeks is well below normal. We’ll see where the season ends, but right now the Arctic has fooled the experts early predictions. But keep the faith, Griff, maybe there’s a ‘one Wadham’ summer in your future.

      • Griff

        Take the bet!
        You keep saying arctic sea ice is getting lower and lower but you won’t take the bet? Why?
        Tell me when we will have a summer with open water at the North Pole!
        If arctic sea ice is getting lower and accelerating all the time like you say surely you can pick a time when we will have open water at the North Pole, so when is it?

      • Griff,

        When will you learn not make predictions about Arctic sea ice? You’re always wrong. As if by magic, no sooner did you proclaim a near record low, than did the sea ice stop melting. It actually grew for two days this week. Yesterday it melted again slightly, but is still above its low this week.

        Unless there is another Arctic cyclone, this year’s minimum is liable to end up ahead of 2012, 2007, 2016, 2015 and 2011. If this week’s low were to hold, which it probably won’t, it would be an unprecedentedly early minimum since 1979. Not predicting, just saying that even this late in the season, no one can know what will happen, except that a repeat of 2012 is off the table.

      • **Except the summer minimum is getting lower **
        The usual nonsense from griff. There has been no decrease in the last 10 years.

      • **This one set of facts completely blows any skeptic argument out of the water.**
        You have only blown yourself up.
        There has been no change in the last 10 years.

    • It matters.
      1. The less ice to melt the more available latent heat to the warm the surrounding water. Latent heat of melting is 334 J of energy to melt 1 g of ice at 0°C. The same amount of energy raises the temperature of that 1g of water to 79C. The ice is a massive heat sink, less and less. Summer ice volume is down 60%.

      2. More exposed water means more mixing through wave action. There is (relatively) warm Atlantic water a few metres down.

      3. More insolation which hinders winter freeze.

      The ice is now almost entirely 1st year ice – thin, porous and structurally weak so each year we are one year closer to another 2012 strength storm and a major melt-out.

      • **The ice is now almost entirely 1st year ice – thin, porous and structurally weak so each year we are one year closer to another 2012 strength storm and a major melt-out.**
        Totally wrong!

          • **You should have clicked on my link **
            Still nonsense. Your link shows half of it is 2 years or older.
            Obviously, you pretend not to read Tony’s posts from a month or so ago where he showed multi=year ice increasing.
            Or is your memory that bad????

    • The summer minimum was never an objective metric, it a case of taking the extreme to make more press impact. More concern with being “effective” rather than being honest. It is highly variable for reasons which have little to do with climate but cherry picking low years a keeping dishonestly silent about subsequent years of recovery allows a false narrative of constant decline.

      sea ice is diminishing more quickly than models can predict.

      It has not diminished at all from it’s level in 2007 when Al Gore and IPCC put the issue on the world’s headlines. It is dishonest to claim it IS declining when it IS NOT declining. Even more dishonest to spin this as “worse than expected”.

      They do not even state by what metric they are assessing the alleged decline. However, all this seems to be the mandatory genuflection in order to get published since the subject of the paper seems to be pointing to a negative feedback to loss of ice. This could go some way to explaining why sea ice has not followed the expected “death spiral” , tipping point and runaway melting everyone was promising.

      So the actual science and data shows that the naive expectation of : less ice = more absorbed heat = more melting ; leading to runaway melting and catastrophic collapse of the Arctic ecosystem is just that : trivial and naive …. and wrong.

      • if the ice were a stock price, you would not argue that it was not declining.

        its declining. volume is the word you are missing

  2. > They are known to be important in the processes by which clouds can become electrified, which causes lightning.
    > They are also known to be able to form the seeds for rain droplets.

    Aha! Global Warming proven to cause thunderstorms. Checkmate draughtists, long live the floodists!

  3. The arctic climate is complicated. link INPs have to be considered in context. The paper really doesn’t do that. My guess is that, for most of the year, the concentration of INPs is largely irrelevant.

    One of the most spectacular effects in the Arctic is the fog banks that form over open water. If you’re in an ice covered area, they are like towering walls rising vertically. I’m not sure of the altitude they reach but it looks like thousands of feet. As far as I can tell, their formation depends entirely on the presence of open water and the relationship between air temperature and water temperature. The concentration of INPs appears to be irrelevant to the process.

  4. Is this article implying that a warmer Arctic will lead to the introduction of more biological organisms into the Arctic Ocean. And that these organisms will lead to more nucleating particles (INPs) entering into the atmosphere above the Arctic Ocean, thereby creating more clouds, and ultimately cooling the atmosphere over the Arctic? Or at least moderating the increase in temperature?

  5. “However, we note that our findings are qualitative in nature and a more quantitative assessment of the relationships between the various measurements should be conducted in future studies.”

    Send more money.

  6. Looks like another Gaia ‘life creates its own biosphere’ kind of paper. As if ice and rain would not exist without the phyto spores. Biologists appear to think that the biosphere is the driving force, when every physicist knows that biological prcesses are at most a small perturbation on the phyisical forces that rule the planet.

      • Photolysis of water melecules in the upper atmosphere. Do that a few billion years and you get an atmosphere with up to 30% oxygen. I know it is fashionable to have blue algae make the stuff, but the numbers don’t add up. Furthermore we know that the process occurs right now: the released Hydrogen accumulates in the Earth’s Hydrogen corona, the bane of UV astrophysicists.

      • You also get the firehose effect if around 2.3 billion years ago everything that could be oxidised had been oxidised, such as iron deposits, thus leaving the oxygen finally to build up in the atmosphere.

  7. I found this totally incomprehensible. I realise they are not writing for the outsider so technical jargon has to be allowable but the writing style is not designed for clarity.

    • I would have to agree. That paper is self contradictory and is full of speculation unsupported by data, and that is probably a tautology but you get what I mean. I am typing this one finger on a phone so no copy and paste quotes but the lack of any chain of logic or causality should be obvious.

  8. Looks like a remarkable feedback loop. More open water yields greater INP’s injected into the atmosphere, as well as more heat and evaporated water.

    This is still the far northern latitudes. “Warmer” is relative. It remains to be an “itch” at the back of my thought processes, much like a prescient clue being impressed upon my conscience, that an open Arctic Ocean for many months of the year is a glaciation trigger.

    It seems to me that it is the open waters ability to dump greater quantities of heat to space is the key issue here. The tropics are self regulating. The middle latitudes are the convergence. It’s where I am.

    • “It seems to me that it is the open waters ability to dump greater quantities of heat to space is the key issue here.”

      Indeed. Open water during the Arctic cold months at ~zero Celsius, as compared to solid ice at, say, -40 Celsius is like a punctured Zeppelin on fire, pissing heat out of the climate system.

  9. Griff, loydo

    “It matters.

    1. The less ice to melt the more available latent heat to the warm the surrounding water.”

    Where in effect do you get your “available [ excess ] heat” from when the energy sum of that machine “Planet Earth” day for day and night for night tends to equilibrium.

    • Two buckets of water. One just frozen -1C the other 80C. Add them together, what temperature is the mix?

        • H ha, you might have to explain that to him/her and to anyone else who’s not so good with math(s).

        • Correct. Melting ice absorbs a surprising amount of energy. The energy to melt a litre of ice is about the same amout of energy needed to raise the temperature of a litre of water by 80C.

          Melting ice takes a lot of energy.

          When it has melted from an area the heat has to start going somewhere else: it goes into raising the temperature of the water. Ice melt is the only reason the summer temps don’t spike like the winter temps,
 excess heat has just melted more ice.

          Ice volume is down 60% in a few decades. Once it has gone, summer temps too will spike and there will be no short term way back, ie a tipping point.

  10. commieBob, arctic fog banks towering up to stratocumulus: › wiki

    Fog – Wikipedia

    Moderate turbulence will typically transform a fog bank, lifting it and breaking it up into shallow convective clouds called stratocumulus.

    And that’s where the “excess” heat goes to : the stratosphere.

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  11. “As Arctic temperatures rise at twice the global rate, sea ice is diminishing more quickly than models can predict.”

    Rubbish. If you can’t easily make your model produce the results you want, then you are not familiar with the basics of modelling, in any discipline.

    • It is also an admission that the models are wrong, but they never seem to understand the implications of their own observation. It seems they blindly go on thinking “oh my, the effect of CO2 is worse than we thought”, without ever wondering if there is something else going on and the models are just wrong, which they admit they are. Strange logic.

      • As a grad student, one thing that tickled me pink, and then purple with outrage, was the computer spreadsheet function that allowed one to click-and-drag a data point on a graph and it automatically adjusted the number in the corresponding spreadsheet to match the new location of the point on the graph. A cheat’s charter.

        While I can see something in their explanation that it is a function to allow economic modelers to see a “this-is-what-it-would-need-to-be-if” scenario, it offended my scientific sensibilities enormously. In a world where “a picture tells a thousand words [and a billion numbers]” it just doesn’t seem right to make reverse-engineering of data so quick and easy.

    • CMIP3 models way overestimated Arctic ice. They partially fixed that in CMIP5 but, in the process, screwed up other climate metrics. By not understanding fundamentals and messing around with multiple parameterizations to get an ECS that “seems about right,” UN IPCC climate modelers get it wrong.

  12. right Arctic temperatures … measured by half a dozen thermometers … at human settlements … the rest “homogonized” from thermometers hundreds to thousands of miles away … no Arctic “temperature” records are fit for purpose …

  13. If bacteria around which ice can nucleate are carried into the atmosphere above the Arctic in late summer, this should increase snowfall rates in early autumn, when there is still open water for evaporation, but the sun has disappeared below the horizon. Increased snowfall should lead to re-formation of the ice in early autumn, so these bacteria seem to be a negative feedback on melting due to summer warming.

  14. Ocean products in the atmosphere is a fascinating subject, probably largely a function of wind, modified by current, surface organisms, jetsam and flotsam. “To test this [sediment bacteria in the air], we used the PWP model. The density profile of Station 3 was used as the initial condition, and the PWP model was forced with the wind stress associated with the late August storm.”

    Interesting paper, wish they had done more and varied atmospheric sampling. Bet there was living phytoplankton in the air where they sampled. Wonder if whale breaching leaves a signature, especially when they hit the water? Necessary sampling in high wind situations not fun and at least one whale species breach more in such.

  15. And of course absolutely no Chlorine is dragged into the upper atmosphere and stratosphere by these processes.

  16. Does anyone know if there are more of these Ice Nucleating Bacteria than there are the latest reports of microplastic particles raining down from the sky in the Arctic. I want to see a bunch of electron microscope pics of some Arctic snow that show these things. I’m thinking we’ll see INB pics but no MP pics….

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