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Climate Hustle

What do Jellyfish teach us about climate change?

Posted on 7 November 2017 by John Abraham

What do Jellyfish teach us about climate change?

A lot. At least that’s what I learned after reading a very recent paper out in the journal Global Climate Change. The article, “Ocean acidification alters zooplankton communities and increases top-down pressure of a cubazoan predator,” was authored by an international team of scientists – the paper looks at impacts of climate change on life in the world’s oceans.

I recall attending a horse-pulling contest as a child. The announcer at the event said something strange that stuck with me all these years. He said that two horses pulling a load at the same time are more effective than if the two horses pulled separately and their loads were added. That is, something about two horses working together made them greater than the sum of their parts. This study is a lot like those horses.

To begin, ocean acidification refers to the changing pH of ocean waters. As humans emit more greenhouse gases (carbon dioxide in particular) into the atmosphere, the chemistry of the oceans change. The effect is that the creatures living in the oceans are experiencing an environmental change that is separate from changing temperatures due to global warming. Scientists want to know how these changes will affect creatures, in particular because the biodiversity in the oceans is so very important to us as humans.

There has been some reporting on studies of calcifying organisms and their susceptibility to changing chemistry in the oceans. For instance, echinoderms, molluscs, corals, and crustaceans have been studied in laboratories and in situ. The studies show that acidification reduces development and survival. Acidification can alter the way these creatures make and maintain their shells.

But the authors of this new study point out that there are many other non-calcifying organisms that may also be impacted by acidification. Even for these creatures, acidification has been shown to have deleterious effects that result in reduced survival, reduced reproductivity, and reduced size.

So how does ocean acidification affect these non-calcifying creatures? One hypothesis is that the new chemistry of the ocean changes these creatures’ metabolism. Upsetting the metabolism means they are less efficient at using caloric resources within their bodies. 

During this study, the authors utilized a very common zooplankton called calanoids. Calanoids make up approximately 80% of the zookplanton by mass. Consequently, they are very important. The authors also identified a predator of the calanoids - the “box jellyfish”. The fancy (scientific) word for box jellyfish is “cubozoa.” The authors wanted to know how changes to water pH affected the survival of the calanoids in the presence of a predator (the cubozoan). 

After bringing both creatures together into carefully designed tanks, the authors waited and watched. In some tanks, they just changed the ocean chemistry and did not introduce the predators. In other tanks, they introduced predators but kept the ocean chemistry fixed. In a third group of tanks, they both changed chemistry and introduced the predator. And then of course, they had control tanks with no chemistry changes or predators.

What they found was really interesting. While both changes to chemistry and introduction of predators affected the populations of calanoids, the simultaneous actions of acidification and predators was greater than the individual actions. So, we see the analogy with the horses.

Why are the combined effects of these two changes more potent? The authors give clues. If, for instance, a more acidic ocean reduces the metabolic efficiency of the creatures, then they will have less energy to escape predators. In fact, these calanoid creatures are known to escape predators by making a jump or a series of jumps. Consequently, in non-altered water, only about 1% of hunting tries are successful. But, in altered water, with less energy for the calanoids, perhaps more jellyfish hunts end in a meal. 

Click here to read the rest

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Comments 1 to 18:

  1. Thanks for this excellent piece. For those who want to read further on jellyfish, they might start with the cleverly named "Spineless."

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  2. Another thing that jelly fish teach us is that we have destroyed our population of sea turtles (who eat jelly fish).  We continue to destroy them by not protecting their nesting sites and by letting plastic bags enter the oceans which they mistake for jelly fish.  The jelly fish then hoover up the larvae of all our commercial species which have a planktonic stage (virtually all of them).  Unless we smarten up and set aside more and more of our Exclusive Economic Zones as strictly no fishing areas, eliminate plastic bags and protect turtle nesting sites, we better get used to eating jelly fish.

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  3. As a chemist, I'd like to comment the author's statement: "As humans emit more greenhouse gases (carbon dioxide, in particular) into the atmosphere, the chemistry of ocean change". At first, it's necessary to clarify that in IPCC list of greenhouse gases only CO2 can dissolve in water and change its acidity (not CH4, N2O, CFCs, etc.). So, the question is: how can the increase of CO2 in the atmosphere to impact on the ocean acidity?

    Simple calculations based on Henry constant for CO2 in pure water and H2CO3 dissociation constant show that change in CO2 partial pressure from 0.0003 to 0.0004 atm (that takes place in last 100 - 150 years) will decrease pH by 0.06. Indeed, this difference will be negligibly small because the solubility CO2 in saline water is less than in pure water, and ocean water contains carbonate-hydrocarbonate and boric acid-borate buffer systems. The composition of ocean water and its acidity are examined in detail in the comprehensive work of the Europen Comission

    Estimation of pH in this work (p.26) gives the value of 8.1 (not acidic!). Of course, the local temporary acidification of ocean is possible, but it is caused not by CO2, but by SO2 and NO2 that are much more acidic than CO2.

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    Moderator Response:

    [TD] See the multipart series "OA Not OK."

    [DB] Also, please see "Seawater Equilibria" and "The Physical Chemistry of Carbon Dioxide Absorption".

  4. Aleks:

    From the preface of your reference:

    "Ocean acidification is an undisputed fact. The ocean presently takes up one-fourth of the carbon CO2 emitted to the atmosphere from human activities. As this CO2 dissolves in the surface ocean, it reacts with seawater to form carbonic acid, increasing ocean acidity and shifting the partitioning of inorganic carbon species towards increased CO2 and dissolved inorganic carbon, and decreased concentration of carbonate ion. Since the beginning of the industrial revolution in the 18th century, surface-ocean acidity has gone up by 30%. The current increase in ocean acidity is a hundred times faster than any previous natural change that has occurred over the last many millions of years. In the case of unabated CO2 emissions the level of ocean acidity will increase to three times the preindustrial level by the end of this century." (my emphasis)

    Chemists who actually work in this field think that ocean acidification is an important problem.  Your assertions are not scientificly based.  Next time try to find a reference that supports your position.

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  5. Aleks says ocean acidification from CO2 is "insignificant". The following is from NOAA:

    "Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years."

    Doesnt look very "insignificant" to me. Ph change also differs from Aleks calculation.

    The article has information on impacts currently on sea life including pteropods, coral, shellfish etc,  and also projected impacts. None of it looks "insignificant". Also detail on data collection etc.

    Relatively small changes can often have large repercussions. We see this as a constant feature in natural world and also technology.

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  6. Thanks for references. I'll try to discuss them. 1) In nigelj post: This article contains general statements without links to original works, mention of one (only!) possible reaction, and explanation of pH value at the beginner's level. 2) The Physical Chemistry of Carbon Dioxide Absorption. In this paper, the absorption of IR-radiation by CO2 is discussed, not the absorption of gas by water. 3) Seawater Equilibria. Here the total carbon dioxide molality of 1.65mmol/kg is given at a partial pressure of CO2 0.000387 bar. So, the Henry constant k= P/m = 0.235. This value is much greater than in NISTWebBook (0.031-0.035), so it seems to be doubtful.

    4) OA not OK. In these 18 articles many chemical processes and parameters are described, but not all. Hydrolysis reactions such as carbonate ion + H2O -> bicarbonate + OH- and the role of buffer systems (carbonate and borate) are not mentioned, the very important data on CO2 solubility in seawater at dfifferent temperatures are not given. In the part 4: "average ocean pH decreases from 8.25 to 8.14 after industrial revolution". The industrial revolution means not only increased emission of CO2 into atmosphere, but also emission of SO2 and NO2 during burning coal and some kinds of oil, development of chemical industry that produces gases much more acidic than CO2. So, "after the industrial revolution" does not mean "because of increase CO2 in atmosphere". Part 14 by Drug Mackie seems to be the most interesting, especially Fig.13. Value of pH near the the ocean surface is ~8.1 in Atlantic and ~7.8 in Pacific: how is this difference compatible with the idea of uniform distribution of CO2 in the atmosphere? And what about explanation of pH decrease by ~0.3 with depth? Which amount of CO2 can be produced by respiration? May be, it would be many times greater than all human produced emission into the atmosphere after industrial revolution.

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  7. Michael sweet, please note that statements made in preface (especially, of collective works) are not always confirmed by real data reported by researchers. In the preface: 'As this CO2 dissolves in the surface ocean, it reacts with sea water to form carbonic acid". See p.20: Reaction of H2CO3 formation is slow, and '... the concentration  of carbonic acid is only about 1/1000 of concentration of dissolved carbon dioxide". Total carbon dioxide (H2CO3 + CO2(aq)) "at higher pHs ionises to form bicarbonate and carbonate ions". Hence, it will be slightly alkaline buffer solution that also contains hydroxyl ions with pH 8.1 (table 1.2, p.24).

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  8. Aleks @6,  sulphur dioxide and nitrogen oxides are not causing ocean acidification because concentrations are massively lower than carbon dioxide as below.

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  9. Nigelj@8, please note that acidity is determined by the concentration of hydrogen ions only, not by molecules of substances. Properties of CO2, NO2, and SO2 that produce H+ in water solutions are quite different. a) CO2 has a relatively small solubility depending on partial pressure, temperature, and water salinity. At 25oC solubility in g/kg water is 1.5 for CO2, ~90 for SO2 . NO2 reacts with water forming HNO2 and HNO3 . b)The main forms of CO 2 are CO2 (aq) and H2CO3 , at that the first one prevails: amount of carbonic acid is about 1000 times less than total amount of dissolved CO2 (link in the post 6, p.20). SO2 and NO2 completely convert into corresponding acids, and sulfite and nitrite ions oxidize to sulfate and nitrate, so eventually we get strong acids H2SO4 and HNO3..
    I'd like to make comparative calculation. Let's pretend that above mentioned 1.5 g CO2 fell into the water only as a result of burning coal and found corresponding amounts of sulfur and nitrogen oxides (it's acceptable because crude oil also contains sulfur and nitrogen). The average content of C, N, and S in coal can be estimated from the data in the following link (pp. 117-118) as C 85, N 1,5, S 1 (mass.%).
    Assuming that the mole ratio of substances in the combustion products corresponds to the ratio C: N : S in the coal, it could be found that together 34 mmole CO2 (from 1.5g), 0.52 mmole NO2 and 0.15 mmole SO2 are formed. Because SO2 and NO2 convert completely to strong acids, total H+ amount would be 0.67 mmole (for H2SO4 only the first dissociation step is taken into account). Amount of H+ from carbonic acid could be found from its concentration (34 mmole/kg) and dissociation constant 4.3* 10-7. Even neglecting above mentioned note that H2CO3 concentration is many times less than total [CO2(aq)] , we find the value of H+ from CO 2 of 0.12 mmol. So, even very simplified calculation shows that SO2 and NO2 produce much more acidity than CO2 .
    Please note that your link is about composition of dry air while SO2 and NO2 almost completely absorbed by air moisture.

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  10. Aleks,

    Both NO2 and SO2 are consumed by bacteria in the environment so they do not accumulate like CO2 does.  In the 1950's and 60's (in the Western countries), large amounts of NO2 and SO2 caused acid rain.  This primarily affected the land because of the immense size of the ocean.  The West has reduced their acid pollution although China and India are currently adding a lot of those chemicals.  

    Since CO2 accumulates in the atmosphere and stays essentially forever it has a much greater affect on the pH of the ocean.  If geoengineering by use of sulfate aerosols were attempted that would affect ocean pH.

    Read the series OA is not OK on SkS to get more information.

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  11. Aleks @9, I get that sulphur dioxide and nitrogen oxides reacts easily with water to produce strong acidity. But that doesnt prove anything by itself because you have to look at total quantities of the various gases surely.

    The issue to me is quantities of sulphur dioxide and nitrogen oxides are so incredibly small compared to CO2,that their overall affect on ocean acidity is likely to be totally insignificant. They have increased over time but no different in rate to CO2. Its total quantities that stand out.

    Clearly the climate science community  think CO2 is the prime suspect, and they do not just guess this stuff, and would have have calculated it.

    If you think differently, you need to show in simple terms total quantities of the various gases CO2, S02, etc in atmosphere, multiplied by acidity strength of each and taking account of how much of each gas turns to acid, and at what rate and so on. Such a thing would require considerable work.

    Im not a chemist, but to repeat its obvious the differences in quantities of CO2 against SO2 and N20  are so huge, so many orders of magnitude, that its hard for me to see SO2 and N2O having significant effect on oceans, unless its in some specific, limited location next to a coal fired power station or something.

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  12. Plus of course what Michael Sweet says. All of this has to be factored into calculation as well. 

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  13. Michael sweet, thanks for interesting note about bacteria eating SO2 and NO2 (give a link, please). It's unclear yet, do bacteria eat these compounds in the air or in water solution? I can give the link about bacteria eating CO2:

    Let me recall once more that CO2 in atmosphere is not Hin solution, and small amounts of SO2 and NO2 produce in water solution  more acid than large amount of CO2. Both these statements are based on real facts and general principles of chemistry. I'd like to see in this discussion concrete objections to specific allegations.                                              About your link to OA is not OK. I have just commented these articles in post 6, and I would be glad to receive from you objections to my comments. 

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  14. aleks @13.

    While you are correct when you say "small amounts of SO2 and NO2 produce in water solution more acid than large amout(s) of CO2," is this relevant to the proverbial price of cheese if there are increasingly "large amount(s) of CO2" within today's oceans that are significantly increasing ocean acidity, while there is not a sign of even the beginings of the "amounts of SO2 and NO2" you talk of. Maybe I have missed something, but you do appear to be talking drivel. Oceans are suffering acidification (more +H) and the cause is indisputably due to rising atmospheric levels of CO2.

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  15. Aleks:

    Everyone who keeps an aquarium is familiar with the nitrogen cycle in water which converts ammonia into nitrogen gas via nitrate ion: NH3-->NO2- --> NO3- --> N2.  Sulfate SO4- also has a natural cycle.  You can easily Google this information.  It is not my job to look up commmon knowledge for you. 

    Harvards "superbug" is unable to convert all the CO2 in the atmosphere to energy as demonstrated by the Keeling curve's yearly increase.  This is an interesting press release but has no bearing on our conversation.

    You have made the assertion that NO2 and SO2 gas contribute to ocean acidification.  You have been refered to posts containing extensive literature citations that show the scientific consensus is that CO2 is causes ocean acidification. 

    Since you are making the claim that scienitsts are incorrect, it is your responsibility to provide data to support your claims.  Seat of the pants arguments unsupported by data or expertise do not count on this site.  It is not my responsibility to summarize the OA is not OK series for you here because you have not bothered to read it yet.

    I have a masters degree in Chemistry and have taught college level chemistry for the past ten years.  I am unimpressed by your claims of novel calculations.  Keep in mind that the chemists who did the experiments described in the OA is not OK series know much more about the acid/base buffer systems in the ocean than either you or I.  They know that the Ka of sulfuric acid is greater than the Ka of carbonic acid.   

    Your naive calculation of relative masses of emitted gasses from an unscrubbed smokestack does not convince anyone familiar with the chemistry.  Today I drove past a coal burning power plant.  There is a dry wall plant built next door that uses the calcium sulfate from the scrubber to make their dry wall.  How much did that sulfer contribute to ocean acidification compared to the CO2 they vented into the atmosphere?  While I drove my car emitted CO2 but no NO2 or SO2.  So much for your calculation.

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  16. I think that NO2 in the ocean is unlikely to contribute significantly to acidification. NO2 is a difficult nutrient to obtain, and is likely to be consumed immediately. Pelagi Bacter Ubique, possibly the most abundant species of all, favors base pairs A-T because they require less nitrogen. The daily struggle for nitrogen defines the entire life of an immense number of marine organisms. 

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  17. Aleks "and small amounts of SO2 and NO2 produce in water solution more acid than large amount of CO2"

    Yes in general, and interesting, but pretty non specific.

    Can you please define in quantities what you mean by small and large ammounts, and how this compares to actual real world ratio in oceans please. Otherwise you aren't demonstrating anything.

    Remember we are talking very small ammounts of SO2 and N20 in atmosphere and gigantic ammounts of CO2 in relative comparison, refer to link I posted. The difference is huge, many orders of magnitude, so even if SO2 and N20 etc are more acidic I doubt this is enough to counter volumes of CO2.

    Like others say published science shows C02 is causing ocean acidity and so duty is on you to prove it wrong in specific and precise detail, taking all things into account.

    Dont get me wrong. SO2 and nitrogen oxides must cause at least some ocean acidity. Ships might release some of these oxides. But  I just cant see how it would be the main factor.

    And the release of at least some S02 doesnt change the fact CO2 is contributing to ocean acidity.

    We should be reducing all these emissions S02, C02 etc as they all cause problems for natural environment. Isn't that the real point?

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  18. Comment #16 should read nitrogen is a difficult nutrient to obtain, not NO2.

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