Eye roller: Global warming affects maple leaves, and the ponds they fall into

From Dartmouth College and the “dead rainbows and starving unicorns” department, complete with artist’s conception:

leaves-pond-ecosystemClimate-warmed leaves change lake ecosystems, Dartmouth-led study finds

HANOVER, N.H. – Rising soil temperatures significantly affect autumn leaves and consequently the food web, appearance and biochemical makeup of the lakes and ponds those leaves fall into, a Dartmouth College-led study finds.

The study is one of the first to rigorously explore climate warming’s impact on “ecological subsidies,” or the exchange of nutrients and organisms between ecosystems. “Our findings could have profound consequences for conceptualizing how climate warming impacts linkages between terrestrial and aquatic ecosystems,” says the study’s lead author Samuel Fey, a visiting scholar at Dartmouth and a postdoctoral fellow at Yale University.

The findings appear today online in the journal Oikos. A PDF is available on request.

The researchers collected maple leaves during autumn from experimental forest plots where the soil had been warmed or left untouched. They added the leaves to experimental freshwater enclosures containing plankton food webs consisting of zooplankton, algae and bacteria, thus creating “no leaf,” “ambient leaf” and “heated leaf” conditions. They then monitored the physical, chemical and biological responses in these artificial ponds until the enclosures froze six weeks later.

The results showed that soil warming caused a two-fold decrease in the leaves’ phosphorus concentrations, and that the addition of these “warmed” leaves to the ponds decreased the water’s phosphorus, dissolved organic carbon and density of bacteria, but improved the water’s clarity and caused a three-fold increase in the density of cladoceran zooplankton, commonly called water fleas. Zooplankton provide a crucial source of food to many larger aquatic organisms such as fish.

“Virtually nothing is known about how climate change may alter ecological subsidies,” Fey says. “Our results suggest that changes in soil temperature can have unexpected consequences for lake ecology and that predicting the consequences of climate change will require research across ecosystem boundaries.”

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88 thoughts on “Eye roller: Global warming affects maple leaves, and the ponds they fall into

  1. If they would get off the Climate Change kick, the study would actually stand on its own merit. But there is always that funding source that forces them to blame global warming.

    • Given that the Red Maple is widespread on the eastern seaboard from Newfoundland to Florida and the even the sugar Maple is found in Georgia and Texas it seems to me that heated soil was hardly necessary. All they had to do was pick up the phone and ask people in Newfoundland and Florida how their forest maples were doing. Personally I dont plan on worrying about a tree which grows across such differing climate zones.

      • Since we are coming up on the spring equinox, it is still winter night in Antarctica, so Vostock might be -80 deg.C or -176 F.
        Dunno what the North African Deserts might be but let’s say just 40 deg C (midday).
        So that’s a 120 deg C range. Well it’s at least a 100 deg C range and we know it CAN get to a 150 deg C range all in the same 24 hour day.
        And due to an argument by Galileo, every temperature in that range must exist at some place between those two extreme points.
        Actually you can draw any continuous line between those two points and every Temperature will exist somewhere on that line.
        So there are an infinite number of places on earth with any temperature in that 120 deg C range.
        So I’m not going to pay attention to what the Temperature is when the leaf falls off a maple tree at Vostock station, nor how brown the water gets when in lands in Vostok Lake.
        G

      • George,
        I think it’s now late [Southern] Autumn in Antarctica, so Vostock is just losing sight of its sun – for months.
        That said – it’s still somewhere I’d rather not visit, being keen on not having extremities drop off from frostbite!
        And I don’t know about African deserts, but I’ve been in dry dock in Dubai with the mercury at over 50C, and had 170F – about 77C – in the sun, anchored off Bandar Mahshah [then] – now Bandar Imam Khomeini, in Iran.
        I don’t know – perhaps Antarctica reaches a ‘high’ of maybe – 40C/F, when it’s high summer in the Northern hemisphere.
        Per the peerless, omniscient (and one even I can edit) Wikipedia: “The lowest natural temperature ever directly recorded at ground level on Earth is −89.2 °C (−128.6 °F; 184.0 K), which was at the Soviet Vostok Station in Antarctica, on July 21, 1983. ” Vostok, Vostock. Whatevveah [And recent -95C, by satellite]
        So probably a 100 degree range on many days.
        It would be interesting to hear what the greatest range, worldwide, in one day is.
        Auto

      • OOoops heck auto, I thought I was on a roll there. You are absolutely correct of course, I was six months out of phase.
        Well when you are reared on the crusty side of the pizza, and then come to live on the cheesy side, sometimes you get some of it in your lap so to speak.
        Thanks for finding that Guffoonery.
        G

      • I was taking the Vostock low as -94 deg.C based on those recent satellite observations for a good part of that plateu. and the official high is about +136.x F in some North African place BUT that was an air Temperature in the shade high, and not a ground surface Temperature.
        So I routinely peg the extreme range possibility at 150 deg C but that African high and Vostock low did not occur anywhere near the same date and year apart, but they could easily heve been on the same day.
        Some people say +90 deg C on the ground is measurable on blacktop.
        The point is that all living things are capable of migrating to where they are comfortable, and a few degrees here or there is quite irrelevant to life on earth.
        I once watched six waterspouts go through an area of the florida keys flats, and literally tear up hundreds of acres of shallow grass covered bottoms, of course destroying almost all of the wildlife on that bottom.
        Five minutes after those tornadoes passed through (we were hiding under a road bridge in a boat) we went back out to those flats, and the tarpon that had been there before the event came right back to the same place. I even managed to catch and release one of them after their whole playground had been blown to smithereens.
        Life will adapt. Human better too.

    • Yes, it is true.
      Year to year variability in rainfall changes the soil temperature regime. Thus, the impact on leaves also accordingly change. In a dry year the temperature goes up and in year the temperature goes down. This is the part of climate change but not the part of global warming. Under such scenario, there will not be any significant change with global warming as it it is insignificant so far. Due to local and regional variations in temperature in association with ecological changes though significant also will not influence the study process.
      Dr. S. Jeevananda Reddy

  2. You can’t put leaves in a closed system and call that a study. Oh the water is clear but so is battery acid. I have some experience with this as I have a 3000 gallon Koi pond next to three 80 foot Oaks.

  3. Warmed by how much (in the experiments)? 0.02C or 4-6 Celcius…? Kinda makes a difference, wouldn’t you think?
    Besides, have we started taking samples of global soil temperatures?
    If the atmosphere has warmed on average (0.5 to 0.8C) and I know, I’m pretending there is no data fudging, how much has that affected the soil. I dont know the details, however I do know how lakes take a long time to warm up and a long time to cool, they lag atmospheric temperatures, I am sure soil is the same if not worst also, I highly doubt 0.8C atmospheric temp increase will transfer into the same increase in soil.

    • Another issue is that they are saying warmer air temperatures cause warmer soil temperatures. I realize it sounds like common sense would agree with that but think a little deeper.
      Beside the issue of lag time that Cbeaudry brings up, what if warmer air temperatures (and more CO2) promote leaf growth? Then the trees grow more leaves which provide more shade for the ground. Might this not cause the microclimate under the tree (and hence the soil) to not have an increase in temperature? I don’t know one way or the other, but without an answer their study is not an analogy for the real world.
      There is also the fact that just warming the soil also isn’t a good analogy for a world were air temperatures increase and cause an increase in soil temperatures. In their study they increased soil temperature but NOT the air temperature around the rest of the tree. Doesn’t it make sense that the tree would react in some way to an increased air temperature that would accompany the increased soil temperature? Without replicating BOTH warmings their study doesn’t match the reality of an increasing air temperature.

    • From the paper:

      We collected leaves for this experiment from a long-term soil warming experiment at the Harvard Forest in central Massachusetts, USA (42 ° 28 ′ N, 72 ° 10 ′ W). Since 2003, the soil in one 30 x 30 m area of mixed deciduous forest has been heated to 5 ° C above the temperature of a nearby 30 x 30 m reference plot using resistance cables buried at 10 cm depth (Melillo et al. 2011, Butler et al. 2012). In the context of global climate change, it is important to note that because 1 ° C of air warming results in less than 1 ° C soil warming (Scheff ers et al. 2014), this magnitude of soil warming corresponds to the most extreme air warming scenarios predicted as a result of climate change by the end of this century.

      The experiment was done in 15 artificially constructed “mesocosms” (5 each of ‘no leaf’’ , ‘ambient leaf’’ and ‘heated leaf’).

  4.  ………..”predicting the consequences of climate change will require research across ecosystem boundaries”. Yes you qualify for research funds from big Government, GreenPeace etc, etc.

  5. This has the sophistication of a first year Biology lab exercise, and about as much relevance to forest ecology. Dartmouth has a reputation for science at the senior high school level…

      • Yes, but the article states quite clearly “The study is one of the first to rigorously explore climate warming’s impact on “ecological subsidies,”
        As it uses the word ‘rigorously’ then that settles it in terms of rigor. And there are the “ecological subsidies,” which sounds like they may be tax deductible, although it depends if these are actually “ecological income” disguised as subsidies. Maybe there is some ‘Leaf Laundering” going on below the surface. So give them a break because….because they are rigorous!

  6. never stop pouring million Tm/year contamination to the foul air, they are almost suffocating in cities…and blame to the Anticyclone

  7. As an experienced leaf raker it’s been my experience that when maple leaves fall they either 1) blow into the lake immediately and sink, 2) get wet and stay and rot on the ground or 3) dry out and blow around and end up as scenario #1 or # 2. None of these have the ground warming the leaves, then the leaves ending up in the water. The problem with the study seems to be that they collected leaves from forest plots and physically moved them to water, most leaves in the real world won’t have humans helping them move to water.

  8. Yes, climate change does effect maple. We have 7 mature sugar maples in the yard, over the last 3 years we’ve had more sap then we could possibly boil. Right now I have about 2 gallons of the gooey, tasty treat in the pantry, not to mention the 14 1-pint gift bottles we gave away last year. I’ll be hosting everyone for pancakes Saturday, my house 7:30 am…. yes there will be bacon, and a very dark french roast … If you feel inclined to bring a gift dark Swiss chocolate is always appreciated

    • Thanks for the invitation, but I’m out of town this weekend – though the fresh squeezed tangerine juice just might change those plans.
      Got plenty of maple syrup here in VT thanks – so much that we’re busy relabeling it in the hope that those people south of here (Dartmouth i.e.) might finally understand what it is (that growing on trees bit has been a tough nut).

    • I can contribute lots of white global warming if it is of any use to you. We have more of the stuff than I have ever seen here before.
      Ian M

      • Sorry Ian, we have plenty. I live in a classic snow-belt, we have about 160 inches on the ground right now, down substantially from the 280 we had last year. The good news is it’s sunny and calm, and the lake-effect-machine is retired for the year because the upper half of Lake Michigan has turned from pristine blue-green into a paler shade of white …

    • wasn’t there a study some years ago that claimed that the Maple syrup industry would be over due to GW?
      I heard it on the CBC so it must be true.

  9. Interesting their study started with the presumption that the soil is warmer due to global warming. I object your honor! Presenting facts not in evidence!
    I have no objection to this study claiming that artificially warming leaves by warming the soil they fell on and then migrating leaves to an artificial controlled environment showed warmth affects the chemistry of the leaves. Who knew that temperature might affect chemical processes. I really never knew that eggs frying in a pan might change their chemical composition due to heat, I always thought it was magic. Thank goodness for GW, without it we’d be blind to such great science.

  10. I cannot stand it. They heat the soils which suggests that they heat them on shorter time scales than occur in nature. How do they account for the reduced warming of several feet of snow and ice cover missing from “heated soil” plots? The premise is that the world is warming when the data for going on two decades tells us otherwise.

  11. Did anyone actually measure the temperature of the soil in the Northeast over the past few years?
    Please consider the following:
    The Great Lakes had high levels of ice last winter.
    Lake Superior still had some ice at the start of last June, which is very unusual.
    Great Lakes water was cooler than normal through the summer.
    This winter the Great Lakes again have very high levels of ice.
    I would assume that, if the lakes were cooler, the soil would be cooler as well.
    Sometimes it might be wise to actually measure the soil temperature, rather than assuming it is warmer, and then warming it further in order to conduct your experiment.

  12. You have to give it to these people! Really! Think of the creativity it takes to come up with these “research projects!” They know they have to find something different to work on, so they come up with some of these incredible “supportive” research programs! If grant money wasn’t available, stupid projects like this wouldn’t happen, and genuine research might actually occur! Of course, there would be a lot less P(iled) H(igher) and D(eeper) candidates being employed if that was so. I wonder if I could get a grant to study how global warming has affected human flatulence over time? It may well be significantly warming the environment, even as it attacks the human nostrils.

    • Tom, you and I would both become pretty creative if our comfortable sinecure was under threat – and you and I might have to go out into the real world to earn a living.
      I’ve worked for a month, and a couple of dozen sessions as a life model, for ‘government’ – and the other forty-plus years in shipping – private sector.
      Auto

  13. …global warming (“good” no longer spend cold)… pouring pollutants greenhouse effect into the air is melting the poles. Besides on melting permafrost will free into the Atmosphere million Tm of methane with big greenhouse effect. This large amount of freshwater to the ocean could stop vertical deep sea currents which depend on starting from surface ↓ downwards on a delicate balance between fresh and salty water and temperatures, and continuing go away slow and cold for the bottom loading nutrients and carrying large heat quantities. Heat from the Sun reaches the equator and currents distribute it throughout the Planet, then…goodbye to our warm climate. The horizontal oceanic currents on surface produced by winds and some others in all levels by the rotation of the Earth West → East, like the Antarctic circumpolar current, rotating all by the Coriolis effect, will continue…but the vertical currents produced by the sinking of horizontal currents of dense salty water that reaches the Poles where the water is sweeter, less salty, and form cold bottom currents going heat transvasing between different latitudes would stop (why are the Grand Banks fishing in cold latitudes?…because over there is the POLAR ICE, freshwater, different sweet/salty density, salty dense water arriving and sinks in a little salty water environment…nutrients that are removed from the bottom cold water and rise to the surface, phytoplankton that feed on nutrients, zooplankton that feed on phytoplankton, fish that feed on zooplankton)… No polar ice over there will be no vertical currents…could reduce the rise of nutrients to the surface and therefore PHYTOPLANKTON SHORTAGE MAY DECREASING ITS VITAL CONTRIBUTION WITH OXYGEN TO THE ATMOSPHERE (90 %)…fish…winds in some places of more warm latitudes carry out the surface hot water permitting the outcropping to surface of water and plankton (the upwelling) from the bottom cold current coming from the Pole, forming other Banks fishing… Without polar ice the sea it could almost stratified into horizontal layers with little energetic movement of water masses in vertical which is what removes fertilizer nutrients from the bottom cold water… Besides lowering salinity of the sea, for that great contribution with freshwater to melt the Poles, will increase evaporation (ebullioscopy: the less salt has, more evaporates) producing gigantic storm clouds as have never seen, that together with altering of the ocean currents, could cool areas of the Planet causing a new ice age… Warming…invasion of tropical diseases carried by their transfer agents, already without the “general winter” containing them would fall upon the World like a plague…can produce a cooling, a new ice age, like living at the North Pole…and less oxygen in the Atmosphere… Is not known to be worse… Go choosing.

    • No polar ice over there will be no vertical currents…could reduce the rise of nutrients to the surface and therefore PHYTOPLANKTON SHORTAGE MAY DECREASING ITS VITAL CONTRIBUTION WITH OXYGEN TO THE ATMOSPHERE (90 %)…fish…
      Whoa there, fella! Time to take your lithium again!

  14. Why is this an “eyeroller”? Because it has the words “climate change” in it? On what basis are you sneering at this work? However, I have to say I agree with Slywolfe above, most of the noted changes seem positive.

    • Welcome back Sir Harry. That is the second you you have fallen off the wagon of denying yourself the pain or pleasure of reading the latest news on WUWT.
      I know what it is like: not today, you say, today I will DO something, not just sit in front of the monitor. But the right hand, with a will of its own, presses on the Firefox icon for WUWT… and it’s game over.

  15. Ecological subsidies to the tune of several trillion and this the best they can do? Let’s see if a geologist can kick this BS in the stomata. 1) sunlight has more effect on the leaves than warming the ground – it certainly is the gorilla in the tree room. 2) did you do a control where you sampled leaves from the ambient trees several weeks earlier when the ground was warmer naturally. 3) when did you start to warm the soil? 4) did you sample ambient trees in Quebec and compare them with ambient trees in In Massachusetts. 5) did you put leaves in a pond in Massachusetts that you had taken from Quebec? and vice versa? 6) did you have to beg your high school teacher to up your science mark so you could get into Dartmouth?

  16. …predicting the consequences of climate change will require research across ecosystem boundaries.

    Of course it will. Climate prognostication based on fantasies is tough work.

  17. Another point that has to be factored in is the insulating value of a layer of fallen leaves covering the earth. Over a few years, you can build up quite a thick layer which would decrease the warming value of the sunlight striking the earth. Anyhow earth itself is quite an excellent insulator.
    So, I wonder how these ‘scientists’ heated their earth, and how much, and whether any practical considerations were taken into account. Not every closed-box experiment has real world application. After all, fire -can- melt steel and you can prove it in an experiment, but it takes a hell of a fire.

  18. The study says that the “warmed” soil where they got the leaves used in this experiment is from the long-term soil warming experiment at the Harvard Experimental Forest http://harvardforest.fas.harvard.edu/soil-warming-experiment
    which warms the soil 5ºC, as predicted by AGW theory, to see what happens to the forest as a result, compared to un-warmed control forest plots.
    So this leaf experiment comes with a big “IF” in front of it — IF global warming indeed does warm up soil temperatures this much, here is one of the results on ecosystems to expect.

  19. “Our findings could have profound consequences … ti da, ti da, ti da …” says the study’s lead author….
    This, sadly, typifies the way press releases hype any research remotely connected to our ever changing climate.

  20. Oikers? Or OINKERS,snouts in the trough? Or rooting for trifles… er… truffles?
    Idle hands do ……whose work?

  21. I own a considerable forest in upstate NY.
    The leaf litter on the ground is very deep. Every fall, new leaves fall on the old litter which over time turns black and becomes rich compost for the trees.
    LITTLE SUN FALLS IN THE FOREST. The summer canopy makes it quite cool and dark and if you are in the fields during the day haying the grass, for example, it is hot. Drive the tractor up the road into the deep forest and it is dark and cool.
    Simple stuff any farmer knows!
    My forest cools the climate. My fields heat it up. Don’t need a PhD to figure this out.

  22. “Virtually nothing is known about how climate change may alter ecological subsidies,” Fey says.
    Well, actually, old fruit, a great deal is known about these “subsides”. They’re called grant money. You tell the big boys ‘n gals with the agenda & the big fat taxpayers funded cheque book, exactly what he/she wants to hear, & you’ll get squillions of £/$/ϵ to spend to your heart’s content! Simple! Sarc off!

  23. In other words one more stupid fantasy from the imaginations of kookie alarmists. Is anyone anywhere doing real research to solve real problems?

  24. A typical academic free-lunch foray into the obvious. If you add some ag-lime to the mix it will even give you faster, better results and ideal water alkalinity for Bass, Bluegill,and Catfish. my lake had fibrous algae and water primrose problems until I started using bacteria to reduce the free phosphorus and nitrates that run off my fields. Any warming would be welcome these last few years as it would give more time for bacterial blooms.

  25. This may be the most stupid thing I’ve ever read. Plus I have to ask how much the soil in central Massachusetts has warmed above baseline over the last 3 months…

  26. …the soil in one 30 x 30 m area of mixed deciduous forest has been heated to 5 ° C above the temperature of a nearby 30 x 30 m reference plot using resistance cables buried at 10 cm depth (Melillo et al. 2011, Butler et al. 2012).

    The refs are paywalled. So, what type of cable at what voltage/current? AC or DC? If DC any ripple component? Shielded cable? Magnetic field intensity/frequency and/or inductive currents in soil/vegetation?
    In other words, are these effects due only to the added heat with other known variables known to have biological and chemical effects carefully considered and isolated?

    • Not being able to find full facts, did they dig up both sets of plots the same and did they balance the moisture due to evaporation in both as these will have a big effect on nutrient take up. It would have the effect of a drought on the trees. If you take the temp and move south till it is 5 deg warmer would the trees even grow there?

  27. ‘“Virtually nothing is known about how climate change may alter ecological subsidies,” Fey says.’
    The use of the word ‘subsidies’ in the above quote left me somewhat baffled. I had never heard it used in a scientific or ecological sense. So, I decided to refresh my understanding of its meaning in case my interpretation had been mistaken. So, I went online and looked up the definition of ‘subsidies.’ Every single source defined the word, with only slight variations, in the following manner (which I copied and pasted here):
    ‘a sum of money granted by the government or a public body to assist an industry or business …’
    Yep, I guess the word still means what it always has! Money grubbing researchers – I salute you!

  28. I think a much bigger issue will be if there are lakes that stop turning over, leading to deoxygenation of the lower layers and loss of aquatic life (even if fish can move up to the surface, the whole food chain will be disrupted).

    • Just what I was thinking. Typical high school might have to borrow some land and equipment, but conceptually it should be well within the range of high school students. That’s not to say it’s bad science.
      Also, it need not be connected to global warming. Establishing the curve for trees’ response to changes in soil temperatures could be useful. Might go into a reference book.

  29. There is no quantification of anything in their findings. How much temperature rise in the soil? How much lower carbon and [phosphorus]? How much more zooplankton? Is this nano science? Are these changes out in the 9th significant figure? That’s a change. But how do these changes affect anything that is sensible or significant to our environment? Those numbers are hopefully in the body of the report but the fact that the summary doesn’t have any of it tells me it is not significant. This findings summary seems to be all about the last sentence. “Our results suggest that changes in temperature can alter ecological subsidies in unanticipated ways, and suggest that accurately predicting the potential consequences of climate change will require conducting research across ecosystem boundaries”. Meaning our study has found that you need to pay us for more studies. This is marketing, not science.

  30. The time is nigh to develop a list of things that climate change does not effect.
    Methinks it will be a very short list!

  31. Surely they looked back at what happened to lake ecology during the warming period between say 1910 and 1940?

  32. Hmm. Seems to me as if they find these alleged changes to be a positive thing, yet they are careful not to say so.

  33. “Our results suggest that changes in soil temperature can have unexpected consequences for lake ecology and that predicting the consequences of climate change will require research across ecosystem boundaries”. “This will require many more years of funded research eventually leading me to a chair and possibly head of the department, or maybe even University President.”
    There. Fixed it for ya.

  34. Yes well, it is a well-known truth to all sedentry minds that:
    The lakes should be exactly the same each year.
    The rains should be equal and even from year to year. No catastrophically wet years or impossibly dry years. Just like it’s been since Jesus walked on the earth. Perfect, average and typical from year to year.
    The number of leaves that fall off each tree should be the same number each year.
    The wind will blow this year just like it did last year, and exactly the same number of leaves will enter the watery graves, to be eaten by the same number of bugs and produce the same amount of methane.
    No variation will be tolerated. So let it be written, so let it be done.

  35. This experiment raised SOIL temperatures 5°C ! That 9°F — it is unlikely (though researchers claim otherwise) that soil temperatures, in the forest, would be raised 5°C even at the extreme high end of IPCC average air temperature predictions for the year 2100. In other words, this is similar to feeding rats 2 pounds of pesticides to see if it might be harmful to humans in trace amounts (measured in ppb).

  36. As an ardent WUWT reader and fanatical coolist, I’m slightly worried by a UK website called the
    Woodland Trust which runs spring watch for certain species – earlier every year?

    • “earlier every year?” No.
      1935 : Winter Heatwave in Britain
      London, Jan 3. – The winter heatwave continues in London with the
      temperature early this morning only 4 degrees below that of June.
      Roses are blooming in Wales, daffodils in the south of England,
      and spring flowers are plentiful in parts of Scotland usually snow
      covered at this time of year. Even on the high hills there is not a speck of snow.
      http://trove.nla.gov.au/ndp/del/article/46677243

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