From the University of Gothenburg , the stuff that keeps some people awake at night. A question; why should we care? And, why should we take any of this seriously when you do things like “We raised the water temperature in miniature ecosystems containing eelgrass meadows, while simultaneously bubbling with carbon-dioxide.” when that “bubbling” would not happen naturally?
Hidden effects of climate change may threaten eelgrass meadows
Some research has shown that the effects of changes in the climate may be weak or even non-existent. This makes it easy to conclude that climate change will ultimately have less impact than previous warnings have predicted. But it could also be explained as direct and indirect effects cancelling each other out, as scientists from the University of Gothenburg, Sweden, show in a paper recently published in PNAS, the esteemed US scientific journal.
To investigate how different climate impacts interact, an experiment was conducted at Kristineberg Marine Research Station.
“We raised the water temperature in miniature ecosystems containing eelgrass meadows, while simultaneously bubbling with carbon-dioxide. This allowed us to simulate a future climate scenario, characterized by both warmer waters and ocean acidification”, explains researcher Christian Alsterberg.
Eelgrass meadows grow in shallow coastal waters and are among the most productive ecosystems in the sea. These meadows are now threatened, not only by climate change but also by overfishing and eutrophication.
“By studying eelgrass meadows on a ecosystem level, we were able to observe how plants and animals interact under changing climatic conditions. This also allowed us to measure the indirect effects, meaning the effects of climate change on an animal or a plant mediated through another organism.”
For example, the metabolism of many crustaceans that live in eelgrass meadows increases when the water temperature rises. This in turn means they need to eat more algae and may consequently graze it more efficiently. At the same time, the growth of benthic microalgae on the sediment surface in the eelgrass meadows will be more vigorous.
Using statistical methods that separates direct and indirect effects, the researchers were able to discern how higher water temperature combined with ocean acidification affects not just individual species but also interactions between species in the ecosystem.
The researchers found that the effects are largely determined by the presence or absence of different fauna, primarily small algae-eating crustaceans. The net effect of changes in temperature and ocean acidification on benthic microalgae is non-existent if there are crustaceans in the ecosystem. But in the absence of crustaceans, the amount of benthic algae is largely controlled by positive and negative direct and indirect effects of higher temperatures and acidification.
The results showed that, without small algae-eating crustaceans in the eelgrass meadows, climate change could pose a much greater threat to their survival.
“The experiment also taught us the importance of investigating climate change using several different approaches, in order to fully understand its effects and to predict future impacts”, says Christian Alsterberg.
Link to article: http://www.pnas.org/content/110/21/8603.full.pdf+html
“Using statistical methods that separates direct and indirect effects,” reveals the BS factor. Statistic methods reveal correlations, but not causation. They are mathematically unable to distinguish between “direct” and “indirect” effects because they are unable to even identify effects or causes.
The sad truth of statistics is that those who do not carefully study the mathematical basis for their use (and the assumptions involved) are extremely prone to self-delusion through mis-assigning significance.
Maybe the eels are on grass for medical reasons?
hunter says:
June 3, 2013 at 10:58 am
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Hunter, because it won’t work that way….
Just putting the buckets in a room with higher ambient CO2…will not lower the pH
…You have to drive enough CO2 into the water to deplete the buffers first….then your pH will drop
The idea that the level of CO2 in the ocean is going to research the same levels as if you bubble up water with CO2 is absurd.
This whole experiment reminds me of an experiment I did when I had fish aquarium as a hobby. In a magazine I read about how you could improve plant growth using CO2.
So, I did. I filled a bottle with water, yeast and sugar and arrange so that any gas from the bottle would bubble up in the aquarium. Then I waited.
After a while when the process had started I return and found that a few of my fish have died and the rest of them were gasping for air.
I quickly realized that the CO2 has pushed out too much of the oxygen from the water.
I then reduced the amount of released CO2 to safe levels into the water and let it run for a week or so, and the plants in the aquarium got a big boost.
The lesson from this experiment is that if feed water with too much CO2 the fish are going to die, not by acidification, but by oxygen deprivation.
They just showed that you have to test the eco-system as a whole, not as individual components.
Test the eel grass by itself for the effects of global warming, and you get a slight improvement in growth. Test it with the algae added and you have a disaster. Add the crustaceans and the system compensates and is stable.
Intuitive when you think about it in terms of population dynamics.
“The researchers found that the effects are largely determined by the presence or absence of different fauna, primarily small algae-eating crustaceans. The net effect of changes in temperature and ocean acidification on benthic microalgae is non-existent if there are crustaceans in the ecosystem. But in the absence of crustaceans […]”
They have drawn the wrong conclusion. Theprincipal factor was clearly the presence or absence of crustaceans.
Latitude,
Thank you for making my point.
Fiddling while Stockholm burns.
@mkelly
“At least they did the experiment in the water where all the hidden heat is supposed to be.”
I thought the hidden heat was supposed to be in the deep parts of the sea. Eelgrass grows in the coastal shallows.
It still amazes me that so-called scientists expect climate to be static until humans get involved. Talk about working with blinders on.
Mike Jonas says:
June 3, 2013 at 2:32 pm
“The researchers found that the effects are largely determined by the presence or absence of different fauna, primarily small algae-eating crustaceans. The net effect of changes in temperature and ocean acidification on benthic microalgae is non-existent if there are crustaceans in the ecosystem. But in the absence of crustaceans […]”
They have drawn the wrong conclusion. Theprincipal factor was clearly the presence or absence of crustaceans.
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Yup, that about sums it up. BTW, for this experiment to be even close to valid, the aquariums would need to be established for at least 6 months, though a year would be much better, and the experiment would need to run at least 6 months. As far as I can tell, the aquariums never had the chance to reach biological stability. This really is on a loosing HS science fair project level.
And with a hand-wave the crucial role of the “algae-eating small crustaceans” is made to vanish to produce a crisis. What natural event is that supposed to emulate? BS on steroids.
OK, but we should also be asking why eel grass grows in shallow waters?
Because they will be nearer to the light for photosynthesis. (Obvious)
Because photosynthesis rapidly removes dissolved CO2 and upper surface waters, even warm ones, quickly replenish this loss from the atmosphere.(remember temperature is the most important criteria for gas dissolution in water, the higher the temperature the less gas dissolves).
When in the RAF I used to visit a small Indian Ocean island in the Adu Attol, RAF Gan. The shallow areas in parts of this island were rich in eel grass growing in temperatures of 25-30C. It seems eel grass has little trouble with temperature extremes all it really wants is abundant sun and CO2.
Yawn. Really – another one? So, what happened to the plight of Ursus Bogus?
Reconcile the Endangered Species Act and evolution.
I really wish that individuals would get their acid- base chemistry straight. An acid-base system is not dipolar like electrical charge. That is, if a solution is less alkaline, it is not more acidic. This is because the neutral state must be considered. You can lower the pH of an alkaline solution solution by simply adding water. It is not more acidic. It is simply less alkaline. In fact, it would never become acidic. Oceans are gigantic buffer systems. At a CO2 level of 5000 ppm (this was the level of CO2 when corals formed), global temperature was the same as it is today and ocean pH was around 7.6, still basic.
Dr. Jim Barrante