Take a deep Breath!

From the personal website of a sharktivist.

And I cite.

Global Warming will be nothing compared to what happens if we lose the oceans.
Because, when that happens, the Phytoplankton production will be reduced to a dangerously low level and the production of 50 to 70% of the world's oxygen supply will be interrupted or completely lost.

Wowza!
Well if we lose the oceans, we better find them again!
Just the incoherent ramblings of just another ordinary dimwit? Far from it - absolutely nothing is ordinary in this person! The most extraordinary attribute: Jupp is none other than the current prez of the SRI (yes the R stands for Research!) and in this function, he jet sets the globe representing Shark conservation, and that would be us (!) at the various international conferences. Is it fair to assume that he may be spouting that same nonsense there and if so, does the Jersey Girl concur and approve of that?

And I cite again.

Sharks are "apex predators" and keep our oceans in healthy balance.
They play an important role in the marine ecosystem, controlling populations of small fish and crustaceans that eat phytoplankton and algae, organisms that produce a large volume of oxygen. Some 70% of the oxygen we breathe comes from the ocean and sharks have been helping to maintain this natural equilibrium for 420 million years or so. Without them, oxygen production would surely be disrupted.

Just another stupidity on some irrelevant website?
Far from it! This is the scientific foundation of the latest, greatest angelic initiative aimed at saving humanity from extinction, or whatever - which incidentally totally confirms my opinion that this is a total bullshit machine and will certainly prevent me from ever signing that petition, lest I become a dimwit and bullshitter by association!

Yes that irritating oygen myth just aint going away!
On the contrary, the meme is evolving and is now morphing into the assertion that on top of leaving us gasping for air, the current demise of Shark stocks will ultimately accelerate global warming, as per Katrien's article cited in this brilliant post by Rick.
Please do read it - and explore the links!

Incidentally, I respect Katrien.
She's done great work with Shark Savers when establishing the Raja Ampat MPA and regularly works with the Shark Alliance - but this is bunk science and having it published in Scribd, apparently the world's largest social reading and publishing site is worrisome.
NOTE - as per her comment below, she has retracted the erroneous statements - kudos!

But I'm digressing as usual.
The myth, as I understand it, goes as follows.

• Sharks are apex predators and as such, they regulate all life in the oceans
• Their demise will ripple down through the food chain all the way to its base, i.e. the Phytoplankton that will be obliterated as a consequence.
• Phytoplankton produces 50-70% of the world's supply of oxygen and its disappearance will lead to the asphyxiation of all life on Earth, including us.
• Moreover, the oceans absorb 80% of the CO2 and once the Phytoplankton is gone, Global Warming will accelerate, methane gas will be released into the atmosphere, the ozone layer will be stripped and we shall all be toast! And Jupp totally agrees!

Right?
No all of this is utter unadulterated moronic bullshit!

1. But how to prove that something is not?

Disprove this!
God is a yellow pig with pink polka dots that resides in the 7th dimension of a parallel universe from where He resonates with our reality.

Utter unadulterated moronic bullshit - and blasphemy & sacrilege to boot?
Yes, maybe - but that's just your opinion. Would you rather believe me if I took up opulent residence in a southern European capital, sported a pointy hat and presided over a cabal of geriatric pedophiles whilst taking from the poor and declaring myself infallible? Would it help my cause if I had the power to declare you an unbeliever and expel you from the community?
Or, how about if I were some old rabid half-dead geezer with a turban and could have you killed for not being faithful, i.e. for being an infidel - would you believe me then?
Yes I may be digressing - but maybe not so much?

But I was not asking you to believe.
I was asking you to prove that I am wrong, as per the frankly dismaying first comment on this post on the Shark Defenders blog. Anonymous, now outed as one Jessica Perry-Targaryen sure got a long, looooong ways to go in her education in the science field, starting from comprehending the difference between a moronic untested hypothesis and verified scientific theory - which incidentally is completely open to falsification!

So let's define the rules of the game here.
In science, law and incidentally, in any rational discourse, he who asserts carries the burden of proof and extraordinary claims require extraordinary evidence!

Not so?
Then, we are in the realm of religion, myth and superstition all the way to quackery, pseudoscience and new age including those conspiracy theories where dissent is forbidden and any proof to the contrary is being dismissed as untrustworthy and fabricated.

Example?
Dozens of eye witnesses seeing a commercial passenger plane slam into the Pentagon are obviously part of the conspiracy - but one single drunken dude stumbling out of a pub in Yorkshire and seeing some light in the sky is proof that we're being visited by extra-terrestrials!

It's really a matter of choice.
You may want to believe the charlatan who appears to have originated this stupidity, or one of his devote disciples and continue asserting that the overfishing of Sharks will lead to the depletion of the planet's oxygen etc - and if so, hasta la vista and have a great life!
The bad news: it may be a short one! The good news: time is infinite - granite into which to chisel calendars is not!

Or, you may want to ask whether there is any proof that the above is true.

So far,
there is not one single shred of evidence, let alone any serious, i.e. peer reviewed scientific paper corroborating the correlation between sharks, oxygen and global warming!
Zilch, Zero, Nada de Nada! At best, this is a completely unverified hypothesis - and as long as that's the case, there's also nothing for me to falsify!

But is the hypothesis at least plausible? Read this!
I think it's total bollocks, and this is why.


2. Sharks and Phytoplankton?

Let's assume that all Sharks are apex predators and keystone species.
"They" are obviously not (do I need to elaborate?) - but for the time being, let's just assume that.

And how about those trophic cascades.
Some of them are well documented, especially for terrestrial habitats. Some of them, especially those that have been postulated for Sharks, are however highly controversial.

But let's assume that "Sharks" sit at the top of "food chains" and that they regulate all life below them. "They" obviously don't and "food chains" are equally mostly a fallacy - but for the time being, let's just assume that to be the case.
Then, such a Shark-controlled food chain could be as follows.

Sardine Run.
Sharks (Duskies, Blacktips etc) eat Sardines (Southern African Pilchard) that eat (principally) small Zooplankton that feeds on Phytoplankton.
And here comes the assumed cascade: Sharks get killed - Sardine population explodes - Zooplankton gets wiped out - Phytoplankton thrives 

= if we want to preserve the oxygen we need to kill all the Sharks!


Oops...

But is that really so?
Seen any Fish population explode as of late?
Yes we have: Lionfish in the Caribbean! But those are invasive introduced species that so far lack any predators - betcha that in 10 years, the picture will be vastly different!

Not so with those Sardines!
The fact is that those Sardines are not part of a food chain, but of a food web.
They are not only the prey of Sharks, they are also the prey of Cetaceans, Birds and many teleost Fishes, meaning that their demise is all but assured. And then there is us, hundreds upon hundreds of artisanal fishermen that scoop them up by the bucket-loads!
So, in the end, there will be just enough Sardines left to spawn and trigger a new run etc - as it should be because as archetypical forage Fish, Sardines undergo boom and bust cycles!!

In brief.
Not all Sharks are apex predators; there are really next to no food chains but instead, the reality consists in complex food webs where there are wide-spread prey- and predator substitution and feedback loops, as in what happens to the exploded Sardines once they have annihilated the Zooplankton, and which population is likely to recover faster; but above all, we have taken on the role of marine apex predator and principal regulator, and this down through the entirety of the trophic levels!
Chances for those postulated cascades to ever eventuate in reality are very low indeed!

And the Phytoplankton?
It could not care less but will continue to boom and bust like it has always done, the former principally depending on the availability of nutrients and light!
Check out the map.


Click for detail - see?
The highest concentrations of Phytoplankton are in cold, nutrient-rich upwellings, in those cold currents that sweep along the continents from the poles and at nutrient-rich river mouths.
Want to get more Phytoplankton? Throw in nutrients - although that, too, is far from being unproblematic!

And here's another map for you.


This is the monthly Chlorophyll map of the Med in 1999.
Chlorophyll is obviously an indicator for Phytoplankton abundance and as you can see, it varies wildly over the year based on environmental factors, like temperature, light, currents and stratification of the water.
Phytoplankton is in no way comparable to, say, a tropical jungle that is meant to last for centuries: in its majority, it is composed of extremely small organisms (e.g. the Cyanobacterium Prochlorococcus marinus that makes up the bulk of it) whose life cycles are extremely short, meaning that they die and then regenerate themselves all the time! That bacterial growth is exponential and will only cease once, say, the Benguela peters out, the nutrients are exhausted or sink back to where there is no more sufficient light for photosynthesis - only to start again in the South and eventually trigger yet another Sardine run!

Nothing whatsoever to do with Sharks!

Example?
The population of the large Sharks and of the large Fishes in the Med which could qualify as apex predators has all but been wiped out . Has there been any according crash in the Med's primary production?
Take a wild guess - see any reference to trophic cascades?

So if it is not Shark fishing, what is actually threatening the production of Phytoplankton?
Probably Global Warming, by stratifying the water layers and impeding those cold, nutrient-rich upwellings!

Example?
The effects of the El Niño along the South American coast: warm water displacing the Humboldt Current, drastic decline in Phytoplankton production, crash of Anchovies and Sardines, starving sea Birds!

Shark-based trophic cascades do of course exist.
But they are not simple and linear and whilst sound in theory, empirical evidence for them is scarce. Predictions like the Shark=Phytoplankton correlation are in no way supported by evidence and actually, just simply stupid in their simplistic and completely implausible assumptions!

So, is there any correlation between Phytoplankton and Sharks?
Yes of course there is! Phytoplankton is the principal driver of the ocean's primary production and as thus, it forms the base of the marine food pyramid - and guess what, in order to fulfill that role, it needs to, gasp: get eaten!
Yes the Phytoplankton will get eaten by herbivores, those will be eaten by carnivores etc - and somewhere near the top of the pyramid, we will start finding the Sharks who could not exist if the whole thing did not start with the Phytoplankton at the bottom!

You heard it here for the first time: if the Phytoplankton does not get eaten, there will be no Sharks!

Like I said.Bottom-up effects are totally unproblematic.
Top-down - not so much!

Long story short?
The Phytoplankton is the basis for most life in the oceans, for which it NEEDS TO GET CONSUMED - and to make exactly that aspect the centerpiece of apocalyptic doomsday scenarios is utter unadulterated moronic bullshit!

Quod erat demonstrandum!

3. Phytoplankton and Oxygen Production?

So plants produce the atmosphere's oxygen, right?

Not so fast!
Plants do indeed produce oxygen and Phytoplankton indeed produces the bulk of the ocean's oxygen that is a bit less than half of the global production. The process is called Photosynthesis and in very!!! abbreviated terms, it consists in taking in CO2, throwing away the O2 and keeping the C for producing plant matter. Thus plants that are growing produce the most oxygen, after which the output of oxygen decreases and is essentially balanced out by the plant's respiration.

BUT!
Once a plant dies, the C it is made of is generally converted back into CO2 by re-combining it with the amount of O2 that was originally thrown away - meaning that in general, plants ARE NOT net producers of oxygen! Read this and yes, it is totally counter-intuitive but true never the less!

Example?
Eutrophication: first there is an algal bloom, then the Algae die, then breathing and thus oxygen-depleting and CO2-producing Bacteria etc consume them - and finally, everything else dies for lack of oxygen!

So where does the oxygen in the atmosphere come from?
Ever since the first Cyanobacteria started producing oxygen a couple of billion years ago, with possibly a big push half a billion years ago, a tiny fraction of the plants that died (or of the animals that ate them) was not re-converted into CO2 but instead, the organic carbon was buried and preserved (e.g. as coal, oil and shale), leaving the excess oxygen in the atmosphere or dissolved in water. This process is called Biosequestration and results in a net reduction of CO2 and in a net production of breathable O2.
Over this very long time span, it is this tiny excess production of Oxygen that has resulted in the actual atmospheric concentration of 21%, a drop from a high of 35%. And yes, it is plausible to assume that up to 70% of that oxygen came (past tense!) from the oceans as a) terrestrial plants only came into being approx half a billion years ago and b) Plankton is particularly prone to sedimentation.

And right now?
Right now, those 21% of atmospheric Oxygen are being circled around via the Oxygen Cycle.
You can see the absolute amounts of what's being done by whom here (note that Photosynthesis (ocean) accounts for less than half of the gain!) and if you do the math, the complete loss of all oceanic photosynthesis would equate to a reduction of atmospheric oxygen levels of one 10,000th or 0.01% per year
But with only 0.5% of all the Planet's Oxygen contained in the Atmosphere, there's plenty of scope for replenishing the shortfall from the other reservoirs! Also, there is some evidence linking an increased level of CO2 to an increase of photosynthesis, meaning that the Oxygen Cycle may be partly self-regulating.

But actually, this discussion is really irrelevant.
In case you have forgotten, Shark fishing will NOT lead to the disappearance of the Phytoplankton anyway!

4. Phytoplankton and Global Warming?

As seen before, the principal threat to the production of Phytoplankton is probably Global Warming - but what about the opposite? Would a decline in Phytoplankton drive Global Warming?

At present, the oceans act as the planet's largest carbon sink.
Check this out.


This is a representation of the Carbon Cycle.
Of interest, most of the carbon is dissolved in the ocean by physio-chemical processes and not due to the photosynthesis by Phytoplankton. Phytoplankton obtains its CO2 from the ocean, not the atmosphere and thus, its effect on the mitigation of atmospheric CO2 concentrations due to Global Warming, if at all, would only be indirect anyway.

But remember the discussion about the Oxygen?
When a plant dies, it is generally re-converted into CO2!
Thus once again, the net effect of the Phytoplankton on the abundance of atmospheric CO2 (and thus Global Warming) is limited to the rate at which its carbon, or that of the animals that eat it gets sequestered!

Want to combat Global Warming?
Stop faffing around about Sharks and Phytoplankton and work on limiting the anthropogenic emissions that cause it!
Reduce your own emissions! Vote for politicians, parties and government that advocate global reductions! Educate others! Do something to enhance carbon sequestration, like we do!
And guess what: you will not only help save Sharks and possibly even the dreaded Phytoplankton, but you will even directly contribute to limiting the depletion of oxygen in the atmosphere!

In closing.
Like a broken record and Erik the Mad Hatter, let me quote myself.

The facts and numbers?
Science is in continuous flux and the data do indeed change – but until they do, the latest peer reviewed science remains the best approximation of the truth.
Thankfully, there are now plenty of resources where anybody can consult the latest insights and data, meaning that those who continue to operate with inflated statistics and outlandish assertions lack any excuses and credibility whatsoever. The facts are plenty horrible as it is – so let’s please stick to those and refrain from the usual stupid inflated hyperbole!

Conservation is never happening in a vacuum - it is being used to advocate legislation that in its marine context will deprive fishermen of income and quite possibly, of their livelihoods. With that in mind, we owe it to them, but also, to ourselves not to cheat and to use misleading perceived "marketing", or whatever, but to be truthful and fact based instead.

The situation for many, if not most species of Shark is really, really dire and there's absolutely no need whatsoever to inflate numbers and to come up with ludicrous propositions like the moronic correlation to the ocean's production of oxygen.

And then there's this.
Assume we succeed in having laws enacted based on misleading data - what would prevent the legislators from repealing them once we got caught out?
Think we would ever get a second chance after such a fiasco?

End of rant!

PS: David here and Patric here!
And Richard's take is here. Colorful and blunt huh? So there: in wise man's politically correct lingo, pushes the envelope of rational, science-based discourse beyond the boundaries of common sense = utter unadulterated moronic bullshit! :)