Via Eurekalert: “A new study concludes that an old, fundamental and widely accepted theory of how and why phytoplankton bloom in the oceans is incorrect. The findings challenge more than 50 years of conventional wisdom about the growth of phytoplankton, which are the ultimate basis for almost all ocean life and major fisheries. And they also raise concerns that global warming, rather than stimulating ocean productivity, may actually curtail it in some places.”
I’m skeptical of the claim made about GW “stratifying the oceans, resulting in less mixing” because as we’ve been told many times, A Warming World Means More Destructive Storms.
So, which is it? AGW means more storms? Less storms? A storm free Arctic?
On the plus side, they included the actual paper with the press release at OSU, unlike many universities that hide it behind a paywall from the public, making them pay for taxpayer funded research twice. Kudos to OSU. – Anthony
Media Release
Findings overturn old theory of phytoplankton growth, raise concerns for ocean productivity
The journal publication the story is based on is available online: http://bit.ly/aTUM3V
CORVALLIS, Ore. – A new study concludes that an old, fundamental and widely accepted theory of how and why phytoplankton bloom in the oceans is incorrect.
The findings challenge more than 50 years of conventional wisdom about the growth of phytoplankton, which are the ultimate basis for almost all ocean life and major fisheries. And they also raise concerns that global warming, rather than stimulating ocean productivity, may actually curtail it in some places.
This analysis was published in the journal Ecology by Michael Behrenfeld, a professor of botany at Oregon State University, and one of the world’s leading experts in the use of remote sensing technology to examine ocean productivity. The study was supported by NASA.
The new research concludes that a theory first developed in 1953 called the “critical depth hypothesis” offers an incomplete and inaccurate explanation for summer phytoplankton blooms that have been observed since the 1800s in the North Atlantic Ocean. These blooms provide the basis for one of the world’s most productive fisheries.
“The old theory made common sense and seemed to explain what people were seeing,” Behrenfeld said.
“It was based on the best science and data that were available at the time, most of which was obtained during the calmer seasons of late spring and early summer,” he said. “But now we have satellite remote sensing technology that provides us with a much more comprehensive view of the oceans on literally a daily basis. And those data strongly contradict the critical depth hypothesis.”
That hypothesis, commonly found in oceanographic textbooks, stated that phytoplankton bloom in temperate oceans in the spring because of improving light conditions – longer and brighter days – and warming of the surface layer. Warm water is less dense than cold water, so springtime warming creates a surface layer that essentially “floats” on top of the cold water below, slows wind-driven mixing and holds the phytoplankton in the sunlit upper layer more of the time, letting them grow faster.
There’s a problem: a nine-year analysis of satellite records of chlorophyll and carbon data indicate that this long-held hypothesis is not true. The rate of phytoplankton accumulation actually begins to surge during the middle of winter, the coldest, darkest time of year.
The fundamental flaw of the previous theory, Behrenfeld said, is that it didn’t adequately account for seasonal changes in the activity of the zooplankton – very tiny marine animals – in particular their feeding rate on the phytoplankton.
“To understand phytoplankton abundance, we’ve been paying way too much attention to phytoplankton growth and way too little attention to loss rates, particularly consumption by zooplankton,” Behrenfeld said. “When zooplankton are abundant and can find food, they eat phytoplankton almost as fast as it grows.”
The new theory that Behrenfeld has developed, called the “dilution-recoupling hypothesis,” suggests that the spring bloom depends on processes occurring earlier in the fall and winter. As winter storms become more frequent and intense, the biologically-rich surface layer mixes with cold, almost clear and lifeless water from deeper levels. This dilutes the concentration of phytoplankton and zooplankton, making it more difficult for the zooplankton to find the phytoplankton and eat them – so more phytoplankton survive and populations begin to increase during the dark, cold days of winter.
In the spring, storms subside and the phytoplankton and zooplankton are no longer regularly diluted. Zooplankton find their prey more easily as the concentration of phytoplankton rises. So even though the phytoplankton get more light and their growth rate increases, the voracious feeding of the zooplankton keeps them largely in-check, and the overall rise in phytoplankton occurs at roughly the same rate from winter to late spring. Eventually in mid-summer, the phytoplankton run out of nutrients and the now abundant zooplankton easily overtake them, and the bloom ends with a rapid crash.
“What the satellite data appear to be telling us is that the physical mixing of water has as much or more to do with the success of the bloom as does the rate of phytoplankton photosynthesis,” Behrenfeld said. “Big blooms appear to require deeper wintertime mixing.”
That’s a concern, he said, because with further global warming, many ocean regions are expected to become warmer and more stratified. In places where this process is operating – which includes the North Atlantic, western North Pacific, and Southern Ocean around Antarctica – that could lead to lower phytoplankton growth and less overall ocean productivity, less life in the oceans. These forces also affect carbon balances in the oceans, and an accurate understanding of them is needed for use in global climate models.
Worth noting, Behrenfeld said, is that some of these regions with large seasonal phytoplankton blooms are among the world’s most dynamic fisheries.
The critical depth hypothesis would suggest that a warmer climate would increase ocean productivity. Behrenfeld’s new hypothesis suggests the opposite.
Behrenfeld said that oceans are very complex, water mixing and currents can be affected by various forces, and more research and observation will be needed to fully understand potential future impacts. However, some oceanographers will need to go back to the drawing board.
“With the satellite record of net population growth rates in the North Atlantic, we can now dismiss the critical depth hypothesis as a valid explanation for bloom initiation,” he wrote in the report.
DR, if nothing else this is perfect example of why the entire peer review process is a total crock……
“This dilutes the concentration of phytoplankton and zooplankton, making it more difficult for the zooplankton to find the phytoplankton and eat them – so more phytoplankton survive and populations begin to increase during the dark, cold days of winter.”
There is so much wrong with this one sentence.
A grade school science project, and it passed peer………………
No I take that back, don’t want to insult grade schoolers
latitude
July 17, 2010 at 10:14 am
Is zooplankton metabolism more dependent on temperature then phytoplankton, that is could a decrease in activity of the zooplankton in mid winter while phytoplankton activity remains more constant be an explanation for the increase in abundance? Have you read the paper, what do you think? I scanned it pretty fast as I do not really have the time to dig into it yet. It looked like the authors were more interested in the measured depth of the mixing layer rather then attributing a cause for the mixing, until the last obligatory for the press AGW reference. On the other hand, I did not see any discussion of the effects of temperature on zooplankton.
Whether or not this paper is correct, I get the feeling that the government is trying to find as many bad things from AGW as possible. Goldman Sachs must be getting antsy at not having those cap-and-trade profits.
As for ocean stratification in the past. Yes, it has happened, but only rarely, for relatively short periods, and when the climate was vastly warmer than now. The last time was about 100 million years ago in the mid-Cretaceous. The Paleocene-Eocene Thermal Maximum (PETM) was apparently not warm enough and/or not long enough to cause stable stratification, despite sommer SST:s about 20 degrees centigrade near the North Pole.
BP needs the money too. Desparately.
In my personal view, the credibility of any scientific study takes a big nose-dive if those results are cited as a reason for being concerned about anthropogenic global warming/climate change — especially if that was the primary justification for conducting the investigation in the first place.
I believe, however, there is a possibility that our medium scale climate fluctuations — Little Ice Age and Medieval Warming — might be the result of natural predator-prey, global-population cycles between zooplankton and phytoplankton. Other than contributing to the CO2 cycle, I speculate that the quantity of these creatures may have a direct effect on the amount of solar energy absorbed by or reflected off the ocean.
As winter storms become more frequent and intense, the biologically-rich surface layer mixes with cold, almost clear and lifeless water from deeper levels.
Oh, noes! All the benthic fauna has gone extinct?
“It’s worse than we etc…”
Someone, or some entity, is certain to fund this professor, whom I am sure has made it clear that accurate conclusions on this subject require at least 20 years of intensive study of the data, which should take him comfortably through to retirement.
If he succeeds in convincing people that his unfounded scare story about linking increased winter storms to the possible collapse of the phytoplankton population, and blaming it on global warming, then good luck to him – give him full marks for knowing how to milk the system with BS. Just don’t forget to pity the poor guys who have to pay for his studies, which is all of us.
This is why I called it a crock! We have been told about increased INTENSITY and FREQUENCY of future storms under AGW. Now we are being led to believe that it will not be enough to prevent stratification!!!!!
I have no issue with the first part of the press release. However, they then tack on AGW in order to secure future funding. Now let’s spot the weasle words relating to ‘future warming’ assumptions.
“expected to become warmer” “could lead” “suggests”
The appeal more for funds are here:
“more research and observation will be needed”
Had the bit about global warming not been added he would have struggled to get more funding.
@latitude: Don’t be so reticent. Let us know how you really feel about this theory. Be a latitude with attitude.
DesertYote says:
July 17, 2010 at 11:44 am
Is zooplankton metabolism more dependent on temperature then phytoplankton
==========================================================
no
Without using words I can’t spell any more, they made the stupidest grade school mistake.
What zoo?
What phyto?
They act like no one knows that phyto “surges” in the winter, then don’t say what phyto, and don’t say if it’s the same one in summer – it’s not.
Most of the zoo population reproduces seasonally, but they don’t define what zoo they are talking about either. rotifers? baby jellyfish? what? most are temperature dependent, and again, the zoo population will consist of vastly different zoos different times of the year.
This paper went through the peer process, which means most of the spelling and punctuation was corrected…
…that’s all.
tty says:
July 17, 2010 at 11:57 am
“As for ocean stratification in the past. Yes, it has happened, but only rarely, for […]”
Thanks, tty!
carrot eater says:
July 17, 2010 at 11:13 am
“How long do you expect such effects from a single storm to last, after all?”
AGW state and increase in frequency and intensity of storms. I hope you can see the contradiction in the report. For most here it was glaring. Or is everything possible under global warming!!!! AGW is on spindly legs and its proponents are bending over backwards to keep it upright.
Following tty’s hinat at the Cretaceous, i looked it up on the wikipedia, and following a link to the “Cool tropics paradox” – poles were ice-free and GCM’s computed very hot tropical temps in the Cretaceous. Proxies OTOH pointed to cooler tropics.
Well, they fixed that by adjusting the proxies.
Watch in horror:
http://en.wikipedia.org/wiki/Cool_tropics_paradox
If only these people would just do their thing silently and not constantly open their mouths talking about the future…
tty says:
July 17, 2010 at 11:57 am
As for ocean stratification in the past. Yes, it has happened, but only rarely, for relatively short periods, and when the climate was vastly warmer than now. The last time was about 100 million years ago in the mid-Cretaceous.
========================================================
tty, look at a map of where they think the continents were during the Cretaceous.
Look at the map and see where we would still be able to find records of stratification.
And then think about why we would believe that.
hint – Mississippi river
latitude says:
July 17, 2010 at 10:14 am
I am embarrassed to say it but this is my field.
We all have our crosses to bear…
Whens zoos are abundant, it’s because their food is abundant, not the other way around.
This makes sense. To me at least. Though that’s not to suggest that makes it a concensus.
They obviously need to get new books, they are reading Chemical Oceanography by Frank Millero. That book is an embarrassment to everyone in this field and people that do not know any better claim it’s the bible.
They don’t seem to cite this anywhere – what gives it away?
This cycle is like the wolf/rabbit boom and bust which I observed in Alaska around 1970 although that cycle was not an annual cycle.
The zooplankton consume the blooming phytoplankton and increase in numbers. By the end of the summer the zooplankton run out of phytoplankton, the zooplankton stop reproducing, and die off. The few remaining phytoplankton begin to increase again in the fall and winter. By the spring the phytoplankton are blooming and the zooplankton begins the cycle again.
Does there have to be a mixing of warm and cold water?
Z says:
July 17, 2010 at 1:30 pm
They don’t seem to cite this anywhere – what gives it away?
===================================================
“That hypothesis, commonly found in oceanographic textbooks”
Z, this is a ‘trick’ paper.
First they try to give the impression that the “Critical Depth Hypothesis” is an excepted theory – it is not – and then they go on to take 9 years to try and explain it away. Which they do not even do that.
The “Critical Depth Hypothesis” is over a 1/2 century old.
Warren, you almost got it all.
Add phototoxicity, heat stress, nutrient upwellings, through in some biorhythms, and you’re there.
Jimbo,
“AGW state and increase in frequency and intensity of storms.”
Even if that were true (and I’m not sure it is, on the frequency), I don’t think it necessarily has the implications you guys are invoking.
The observed thermocline and halocline are going to fluctuate with conditions, but I don’t see that some increase in hurricane intensity should necessarily play a huge role in those, beyond the area in and around the storm path, and beyond the time period the storm happens to be there.
If you’re trying to craft some sort of gotcha or claim of inconsistency here, it’s going to take some more work to demonstrate, I think.
through?? change that to “throw” LOL
I know Anthony, put the oreos down
DoctorJJ says:
July 17, 2010 at 9:42 am
Warming means more storms which means more nutrients and more mixing, so theory FAIL.
NEXT!!!
__________________________________________________________
While I read the article the same “wait a minute” occurred to me in that the basic mantra of AGW is, and I believe always has been ever increasing storms.
Now a subtle nudge in the opposite direction seemingly suggesting us to ignore the “tidal waves” behind the curtain?
Okay, with my head hurting, whether GW or AGW, OSU sees a decrease in storms, though not the only mechanism, but surely a major mechanism, as decreasing.
Got it…………….I think………..indoctrination is really hard on me.
Maybe he’s wrong, maybe he’s right.
Only really 2 things to do:
1) Write up a counterexample, debunking the theory.
2) Support the theory with additional experimentation.
Not sure what all the armchair science is about here.
“Behrenfeld said that oceans are very complex, water mixing and currents can be affected by various forces, and more research and observation will be needed to fully understand potential future impacts. However, some oceanographers will need to go back to the drawing board.”
I strongly suspect most of them need to do that including Dr. Behrenfeild. The critical depth hypothesis is not dead and the “dilution-recoupling hypothesis,” has not replaced it. Both appear to be over simplified. What this paper does illustrate is how little the oceanographers know. I suspect they know even less then the climatologists and we know how good their knowledge base is.
He is absolutely correct in saying “oceans are very complex” and more research is needed. It is not that I do not like remote sensing, it is simply that uncalibrated by real empirical data it is noting short of speculation. Time to get out the “Nanson Bottles” and get to work.
I would like someone with expertise in this field work out for us the ramifications of this theory for specific geographical locations. How far north is Behrenfield looking? Does his theory explain the separation of zooplankton and phytoplankton in Hudson’s Bay, with its highly stratified hydrographic profile? How does his theory work out in relation to the well-mixed waters of the Bay of Fundy and adjacent waters in the Gulf of Maine? The Bay of Fundy’s waters get thoroughly mixed via extreme tides, while Hudson’s Bay is highly stratified due to a brackish surface layer from the many rivers that empty into this body of water. So one does not even need ‘global warming’ to test his hypothesis. Would not phytoplankton and zooplankton go through population cycles independent of the time of year and other factors if extreme stratification occurred? And would not limiting nutrients be an even bigger concern than zooplankton blooms if such stratification persisted?