Global marine analysis suggests food chain collapse

October 12, 2015
Credit: Tiago Fioreze / Wikipedia

A world-first global analysis of marine responses to climbing human CO2 emissions has painted a grim picture of future fisheries and ocean ecosystems.

Published today in the journal Proceedings of the National Academy of Sciences (PNAS), marine ecologists from the University of Adelaide say the expected ocean acidification and warming is likely to produce a reduction in diversity and numbers of various key that underpin around the world.

"This 'simplification' of our oceans will have profound consequences for our current way of life, particularly for coastal populations and those that rely on oceans for food and trade," says Associate Professor Ivan Nagelkerken, Australian Research Council (ARC) Future Fellow with the University's Environment Institute.

Associate Professor Nagelkerken and fellow University of Adelaide marine ecologist Professor Sean Connell have conducted a 'meta-analysis' of the data from 632 published experiments covering tropical to artic waters, and a range of ecosystems from coral reefs, through kelp forests to open oceans.

"We know relatively little about how climate change will affect the marine environment," says Professor Connell. "Until now, there has been almost total reliance on qualitative reviews and perspectives of potential global change. Where quantitative assessments exist, they typically focus on single stressors, single ecosystems or single species.

"This analysis combines the results of all these experiments to study the combined effects of multiple stressors on whole communities, including species interactions and different measures of responses to climate change."

The researchers found that there would be "limited scope" for acclimation to warmer waters and acidification. Very few species will escape the negative effects of increasing CO2, with an expected large reduction in species diversity and abundance across the globe. One exception will be microorganisms, which are expected to increase in number and diversity.

From a total food web point of view, primary production from the smallest plankton is expected to increase in the warmer waters but this often doesn't translate into secondary production (the zooplankton and smaller fish) which shows decreased productivity under .

"With higher metabolic rates in the warmer water, and therefore a greater demand for food, there is a mismatch with less food available for carnivores—the bigger fish that fisheries industries are based around," says Associate Professor Nagelkerken. "There will be a species collapse from the top of the food chain down."

The analysis also showed that with warmer waters or increased acidification or both, there would be deleterious impacts on habitat-forming species for example coral, oysters and mussels. Any slight change in the health of habitats would have a broad impact on a wide range of species these reefs harbour.

Another finding was that acidification would lead to a decline in dimethylsulfide gas (DMS) production by ocean plankton which helps cloud formation and therefore in controlling the Earth's heat exchange.

Explore further: Ocean acidification leaving fish in the dark

More information: Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1510856112

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22 comments

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gkam
3.5 / 5 (13) Oct 12, 2015
Greed and ignorance and political prejudice will kill us all. We have lost half of the biomass in the seas:

http://www.cnn.co...dex.html

We depend on the bottom of the oceanic food chain for half our food and Oxygen. Are Exxon and BP and Exxon going to be selling us oxygen for our own good?
Returners
1.4 / 5 (19) Oct 12, 2015
"With higher metabolic rates in the warmer water, and therefore a greater demand for food, there is a mismatch with less food available for carnivores—the bigger fish that fisheries industries are based around," says Associate Professor Nagelkerken. "There will be a species collapse from the top of the food chain down."


Oh my god, you lying sack of trash.

some of the largest aquatic predators in the fossil record lived when the atmosphere was supposedly 1600ppm CO2.

You are a fraud.
gkam
3.3 / 5 (12) Oct 12, 2015
"some of the largest aquatic predators in the fossil record lived when the atmosphere was supposedly 1600ppm CO2."

Do you have a reference?
leetennant
4.7 / 5 (12) Oct 12, 2015
With the other articles on Antarctic shelf collapse and sea level rise, it's good to know we'll starve to death first. What a relief! I mean, we could do something to prevent the problem instead but, what are the odds?
Returners
1.5 / 5 (16) Oct 12, 2015
"some of the largest aquatic predators in the fossil record lived when the atmosphere was supposedly 1600ppm CO2."

Do you have a reference?

Um...
there used to be giant salt-water reptillians (sometimes mistakenly called dinosaurs though they are not dinosaurs) and other such critters.

https://en.wikipe...iosauria

Plesiosaurs first appeared in the latest Triassic Period

They had a worldwide oceanic distribution.

some of them reaching a length of up to seventeen metres


That's over 50 feet in length, longer than even the largest Great White ever discovered

Triassic:

Mean atmospheric CO
2 content over period duration ca. 1750 ppm[2]
(6 times pre-industrial level)
.


It appears I was mistaken after all...the Triassic had even more atmospheric CO2 than I recalled.

These people are frauds.
jeffensley
2.1 / 5 (18) Oct 12, 2015
God, just knock it off people. Expected, predicted, estimated, modeled = meaningless. Lets deal with the reality of over-harvesting before continuing to give these doomsday prophecies more credit than they deserve. Over-harvesting is something very real and very happening in the present and something we actually have a modicum of control over, unlike the climate.
leetennant
3.9 / 5 (15) Oct 12, 2015
I'd love to know how you define "over-harvesting" jeffensley if you refuse to take into account any predicted or projected population and migration data for fish species. Or the impact of climatic changes and acidification on those populations. Do you just make it up?

*stupid question*. Of course you do!
jeffensley
1.8 / 5 (16) Oct 12, 2015
Sorry but reality can once again point the way without help of the above predictions and projections. You know you've over-harvested when you start catching fewer and younger fish. See... and I didn't even have to use Excel.
gkam
3.2 / 5 (11) Oct 12, 2015
Uh, I do not use models or projections, I watch what concerned us many decades ago becoming manifest even earlier than we originally feared.
leetennant
4.1 / 5 (14) Oct 12, 2015
The jeffensley and gkam methods of food chain planning: fish until you run out and then stop.
Thanks for that! I can't understand why we have a problem.
leetennant
4.6 / 5 (12) Oct 12, 2015
Sorry gkam - I misread your comment as supporting jeffensley (which I admit I thought was odd).
JVK
1.8 / 5 (10) Oct 12, 2015
See also: Increased acidification has a profound effect on the interactions between the cyanobacterium Synechococcus sp. WH7803 and its viruses http://femsec.oxf...133.long

Excerpt: "Increased anthropogenic CO2 emissions are expected to cause a drop in oceanic pH of c. 0.4 units within this century. According to current assessments, the consequences of this are limited for oceanic Cyanobacteria, and absent for viruses."

This means the proliferation of viruses could lead to the death of all organisms that cannot quickly adapt, since viruses require only a single nutrient-dependent amino acid substitution, which supports virulence in host cells linked to different host organisms outside the typical biophysical constraints of RNA-mediated protein folding chemistry.
jeffensley
1.7 / 5 (11) Oct 12, 2015
The jeffensley and gkam methods of food chain planning: fish until you run out and then stop.
Thanks for that! I can't understand why we have a problem.


Great mischaracterization of my post. Thanks for contributing to intelligent discourse.
leetennant
4.6 / 5 (11) Oct 13, 2015
Oh, so you didn't say that you don't need data to understand the population of a fish species and the projected impact of various climatic and ocean quality variables but instead just waited till they were over-harvested, which you determined by the catch. You said something different. Please, enlighten me.
Multivac jr_
5 / 5 (6) Oct 13, 2015
some of the largest aquatic predators in the fossil record lived when the atmosphere was supposedly 1600ppm CO2.

You are a fraud.


Perhaps those creatures were adapted to those conditions? Or they all had equally-bad vision relative to aquatic animals today? Or both?

But anyway, at this point we've quite possibly already crossed one or more critical ecological points of no return, so all the bickering over the significance of atmospheric/anthropogenic CO2 to the ocean's pH or the issue of how to turn this and other troubling trends around is likely already moot (but our consumption-orgy sure was fun while it lasted!).

I guess that means the only thing we can really do is find someone to blame for the most epic hangover in human history (since a hangover tends to be proportional to the intensity of the party). Bickering and casting blame won't actually help fix anything, but they've always been popular ways to pass the time.
JVK
1 / 5 (9) Oct 13, 2015
...the only thing we can really do is find someone to blame for the most epic hangover in human history...


Agreed

"...the proliferation of viruses could lead to the death of all organisms that cannot quickly adapt, since viruses require only a single nutrient-dependent amino acid substitution, which supports virulence in host cells linked to different host organisms outside the typical biophysical constraints of RNA-mediated protein folding chemistry."

This means neo-Darwinian theorists will be blamed for touting the pseudoscientific nonsense about evolution without considering the role of viruses in perturbed protein folding. It seems fitting that the theorists have probably led to the destruction of all life on Earth, since most of them reached a consensus on what they thought was science based on their ignorance.

https://www.youtu...9VeFgh8E Science Literacy | 2.1 Scientific Consensus - How It Forms
TheGhostofOtto1923
3 / 5 (2) Oct 13, 2015
Uh, I do not use models or projections, I watch what concerned us many decades ago becoming manifest even earlier than we originally feared
Because george kamburoff IS... The Watcher.
https://www.youtu...CtI_mTns

"Every night mr slackass would belch himself to sleep with gin-soaked 'recollections' of his proud days as a member of" the Business of environmental management.

Reality or hallucination?

Even Watchers need valid and relevant educations, things which george has proven time and again he does not possess.
JVK
1 / 5 (7) Oct 13, 2015
But, what about the viruses, "TheGhostofOtto1923"?

Who's watching them? Is there a consensus of whose job it should be to prevent us from death by evolutionary theory?
jeffensley
1 / 5 (6) Oct 14, 2015
Oh, so you didn't say that you don't need data to understand the population of a fish species and the projected impact of various climatic and ocean quality variables but instead just waited till they were over-harvested, which you determined by the catch. You said something different. Please, enlighten me.


What I didn't say was "fish until you run out and then stop." I even quoted you for the sake of context. I would have thought it would have been obvious to what I was referring.
Returners
1 / 5 (6) Oct 15, 2015
You gotta blame the Chinese for a lot of this anyway, because they are the ones who do disgustingly wasteful practices in fisheries, such as catching sharks and de-finning them by the hundreds and tossing them back over-board still alive, bleeding to death...and that's just what they caught on camera.

If someone got caught doing something like this in US waters, they'd go to prison.

Worst case they should have used it for cat food or dog food or fertilizer, or bait for some other type of fish, but no, they throw it overboard missing all it's fins and still breathing.

Now it's not a matter of intelligence, or education, because the Chinese have the highest average IQ on Earth, and the best maths training, and many of the best scientists...so do they just not give a damn?

Returners
1 / 5 (5) Oct 15, 2015
Worst part about it is, if everybody ate as much fish as nutritionists say we're supposed to eat, the oceans would collapse within a couple years anyway. Everything would be extinct.

Now when the shrimp and the crab and the oysters and clams and fish all go extinct from over-fishing and waste, I wonder what we'll eat from the ocean?

Algae?
Sea worms?
Jellyfish? Are there any jellyfish species that are both safe and easy to catch, and also good to eat?

There's some really, really weird ocean life that lives out on the abyssal plains and also in trenches. stuff I don't know the name of but kinda creepy looking,..primitive, permanent dark-dwelling animals which don't have eyes or mouths in some cases, or in others they're nothing but a mouth and stomache, etc. Maybe we'll start eating that stuff when all the fish go extinct.
philstacy9
1 / 5 (3) Oct 17, 2015
Freeman Dyson says carbon is good.

http://www.thegwp...its1.pdf

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