Guest Post by Willis Eschenbach
Following on from Anthony’s article, here are my thoughts about the phytoplankton paper “Global phytoplankton decline over the past century”, by Daniel G. Boyce, Marlon R. Lewis & Boris Worm.
I started to write about this earlier, but I decided to wait until I had the actual paper. The paper in question is behind a paywall at Nature Magazine, but through my sub-oceanic channels (h/t to WS) I have obtained a copy. The paper makes two main claims, that: a) the numbers of phytoplankton have been cut by more than half since 1900, and b) the general warming of the global oceans is the reason for the declining numbers of phytoplankton.
First, what are phytoplankton when they are at home, and where is their home? Plankton are the ubiquitous soup of microscopic life in the ocean. Phytoplankon are the plant-like members of the plankton, the ones that contain chlorophyll and feed on sunshine. Phytoplankton are to the ocean what plant life is to the land. Almost all oceanic life depends on phytoplankton. Other than a thin strip of seaweeds and sea grasses along the coasts, phytoplankton are the microscopic plants that are the foundation of the vast entire oceanic food chain. Without phytoplankton there would be no deep water oceanic life to speak of. Figure 1 shows where you find phytoplankton:
Figure 1. Global distribution of phytoplankton. Lowest concentration is purple and blue, middle concentration is green, highest concentration is yellow and red. Source http://www.nasa.gov/vision/earth/environment/0702_planktoncloud.html
So where did the Nature paper go wrong?
The short answer is that I don’t know … but I don’t believe their results. The paper is very detailed, in particular the Supplementary Online Information (SOI). It all seems well thought out and investigated … but I don’t believe their results. They have noted and discussed various sources of error. They have compared the use of Secchi disks as a proxy, and covered most of the ground clearly … and I still don’t believe their results. Here’s exactly why I don’t believe them.
This is their abstract (emphasis mine):
In the oceans, ubiquitous microscopic phototrophs (phytoplankton) account for approximately half the production of organic matter on Earth. Analyses of satellite-derived phytoplankton concentration (available since 1979) have suggested decadal-scale fluctuations linked to climate forcing, but the length of this record is insufficient to resolve longer-term trends.
Here we combine available ocean transparency measurements and in situ chlorophyll observations to estimate the time dependence of phytoplankton biomass at local, regional and global scales since 1899. We observe declines in eight out of ten ocean regions, and estimate a global rate of decline of ~1% of the global median per year. Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends. These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures. We conclude that global phytoplankton concentration has declined over the past century; this decline will need to be considered in future studies of marine ecosystems, geochemical cycling, ocean circulation and fisheries.
The first clue to where they went wrong is visible in Fig. 1. Although as you can see there is more phytoplankton in the cooler regions of the north, the same is not true in the corresponding regions in the south despite the ocean temperatures being very similar. In addition, there are many places where the ocean is warm (e.g. tropical coasts) that have lots of phytoplankton, while in other warm areas there is very little phytoplankton.
The rude truth of phytoplankton is this: phytoplankton growth is generally not limited by temperature. Instead, it is limited by nutrients. Where nutrients are plentiful, the phytoplankton grow regardless of temperature. Nutrients are more common along the coastline, where sub-oceanic currents come to the surface bringing nutrients from the deep ocean floor, and rivers bring nutrients from inland. For example, in Fig. 1 you can see the nutrients from the Amazon river causing the red area at the river mouth (north-east South American coast).
Indeed, the fact that phytoplankton are generally nutrient limited rather than temperature limited has been demonstrated in the “ocean fertilization” experiments using rust. If you spread a shipload of rust (iron oxide) out into the tropical ocean, you generally get an immediate bloom of phytoplankton. Temperature is not the problem.
So to start with, the idea that increasing temperature automatically leads to decreasing phytoplankton is not generally true. There are vast areas of the ocean where higher temperatures are correlated with more phytoplankton. For example, the warmer deep tropics generally have more phytoplankton than the cooler adjacent subtropics.
The paper’s most unbelievable claim, however, is their calculation that since 1899, the density of phytoplankon has been decreasing annually by 0.006 milligrams per cubic metre (mg m-3). They give the current global density of phytoplankton as being 0.56 mg m-3. Thus they are claiming that globally the concentration of phytoplankton has dropped by more than 50% over the last century.
Now, a half century ago I learned to sail on San Francisco Bay. Since then I’ve spent a good chunk of my lifetime at sea, as a commercial fisherman from California to the Bering Sea, as a sailboat delivery crewman, as a commercial and sport diver, and as a surfer. And call me crazy, but I simply don’t believe that the sea only has half the phytoplankton that it had in 1900. If that were true, it would not take satellites and complex mathematical analysis to show it. People would have noticed it many years ago.
I say this because phytoplankton are the base of almost the entire mass of oceanic life. They are what almost all other life in the ocean ultimately feeds on, predators and prey as well. The authors of the study do not seem to realize that if the total amount of phytoplankton were cut by more than half as they claim, the total mass of almost all living creatures in the open ocean would be cut about in half as well. No way around it, every farmer knows the equation. Half the feed means half the weight of the animals.
And I see no evidence of that having happened over the last century. It certainly does not accord with my own extensive practical experience of the ocean. And I see no one else making the claim that we only have half the total mass of deep-water oceanic life that we had a century ago..
The other thing that makes their claimed temperature/phytoplankton link very doubtful is that according to the HadISST dataset, the global ocean surface temperature has only increased by four tenths of a degree C in the last hundred years.
Four tenths of a degree … an almost un-noticeable amount. Yet their paper says (emphasis mine):
Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends. These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures.
These kinds of claims drive me nuts. Is there anyone out there that truly believes that a change of global average ocean temperature of four tenths of a degree C over the last hundred years has cut the total mass of phytoplankton, and thus the total mass of all oceanic creatures, in half? Really?
So that’s why I say I don’t know where their math went wrong, but I don’t believe their results. I don’t believe we’ve lost about half the total mass of all oceanic creatures. Half the planet’s open ocean dwellers? Where is the evidence to support that outrageous claim? And I don’t believe that an ocean temperature change of four tenths of a degree over a century has made much difference to phytoplankton levels, as they grow at all temperatures.
Why don’t I know where their math went wrong? Unfortunately, they have not posted up the data that they actually used. Nor have they shown any of their data in the form of graphs or tables. Instead, they have shown model results, and merely pointed to general websites where a variety of datasets are maintained. So we don’t know, for example, whether they used the 1° grid version or the 2.5° grid version of a given dataset. Nor have they posted the computer code that they used in the analysis. Plus, the very first link in their paper to the first and most important data source is dead.
Grrrr … but dead link or not, pointing to a website as the data source in their kind of paper is meaningless. To do the analysis, they must have created a database of all of the observations, with the meta data, and the details for the type etc. for each observation. If they would include that database and their code in the SOI, then someone might be able to figure out where their math went wrong … my guess is that it may be due to overfitting or misfitting of their GAM model, but that’s just a wild guess.
It is a shame that they did not post their data and code, because other than the lack of data and code it is a fascinating analysis of a very interesting dataset. I don’t accept their analysis of the data because it doesn’t pass the “reasonableness” test, but that doesn’t mean that the dataset does not contain valuable information.
[Update] An alert reader noted that the image in Figure 1 was of a particular month and not a yearly average. So I’ve made a short movie of the variations in plankton over the year.
Figure 2. Monthly movie of plankton concentrations. Click on image to see animation.
Why yes, if the oceans get warmer, it means that this reaction gets more prominent
Co3 2-+ acid = 2H3O 1+ => CO2 + 2H2O
Simple chemistry. (that is where Al Gore made his big mistake – cause and effect, he put it the wrong way around)
So global warming is good for getting rid of the extra acid that we have been putting in the oceans. I would also think that that makes the oceans cleaner and would therefore also submit that warmer sea water must be good for (plankton) life. Unless they need the CO2 in the CO3 form?
I still think it is rather the poisons in our waste water (COD etc) that may be killing the plankton (if their numbers are dwindling).
Gail, you bring up good points as always.
The biggest flaw I see with this paper, is the same flaw I see with all climate science.
And yes this is a climate science paper trying to disguise itself as biology.
They make the assumption that the phyto levels 100 years ago, were ‘normal’.
First, they need to establish that ‘normal’ line.
It’s just as possible that something happened 100 years ago that created a huge world wide plankton bloom. This is actually more likely.
And just like temperature records, when you start at a high, it has no where to do but down.
Is it possibleto make an FOI requestfor the data?
dh7fb says:
August 1, 2010 at 7:56 am
Look here: http://www.nature.com/nature/journal/v466/n7306/fig_tab/nature09268_F4.html
and search the statistical significance! 🙂
___________________________________________________________________
My computer is real old so it is a bit hard for me to read the graphs.
Am I seeing a huge spike in the amount of plankton in the 1930’s corresponding to the dust bowl????
or you could just look at the volcanic dust index prior to the 1900’s to see where all that plankton fertilizer came from and why plankton leves were so high in the early 1900’s
http://rankexploits.com/musings/wp-content/uploads/2008/01/histvolcanoerup.jpg
“why plankton leves”
plankton doesn’t have leaves!
should be “levels”
dh7fb says:
August 1, 2010 at 7:56 am
“[…]Look here: http://www.nature.com/nature/journal/v466/n7306/fig_tab/nature09268_F4.html
and search the statistical significance! :-)”
Thanks. Wild variability in there. There seems to be some decline in some areas.
Here’s an idea: Humanity’s impact on the oceans is mostly that we extract millions of tons of fish every year. If we wouldn’t, all the biomass would be recycled by the ecosystem; dead fish would become raw material for other creatures. Fish poo would become raw material for phytoplancton. Could this not be the real cause for nutrient depletion?
In fisheries science it’s called shifting baselines. Fact is we are taking about 1 billion tons of organic matter – fish – from the oceans every decade and have been doing so for decades. Most of the fish taken are carnivorous fish which eat [plankton] filter feeders.
Why or why is climate change assumed to be the reason? Oh I get it. They are ‘climate scientists’ who know sqat about the ongoing fishing holocaust. It must be ‘their’ science because fishing doesn’t pay their wages. Someone slit their gills please.
I see one purpose for this paper. It is the reference paper for applying for grants to visit various tropical paradises to study the layers of mud from the last 100 years to do a plankton count.
The data will then be correlated with the made up worldwide grid temperatures to select those mud samples to be included in the a report. Samples with no trend will be eliminated as having to much noise and the data from increasing plankton counts will be inverted in the Mannomatic “statistical analysis.” Snippets of the raw data will be leaked to Steve to start a new controversy that will will require more conferences and studies in tropical paradises until retirement.
Like Willis and others, I can’t believe that the tiny amount of temperature change we’ve had in 110 years could have done such a horrific deed (40% reduction in phytoplankton since around 1950) , especially when you consider that the world was 1 to 2 degrees warmer, for about 1,000 years, about 8,000 years ago, and was 2 to 3 degrees warmer during the last interglacial.
I don’t think that any of the sea floor cores have picked up large reductions in phytoplankton during interglacials.
And the mechanism proposed for the big decline — warmer waters overlying nutrient rich deep water, preventing nutrients from getting to the surface — doesn’t work for most of the places where the decline in phytoplankon is observed — like sub polar areas, north Pacific. [Note that the authors aren’t saying that plankton doesn’t grow as well in warm water — they are instead claiming that warmer ocean water will more effectively overlay the cooler deep waters which have the nutrients, thus causing nutrient deficits near the surface.]
I don’t necessarily disbelieve the calculations out of hand. The authors themselves note that there were some large areas which didn’t have enough historical data — I think parts of the Southern Ocean, where there are large springtime blooms — so that the full picture might show different level of decline. Or, the figures COULD be seriously in error. I would like the authors to make their data and methods available for audit. Otherwise, they might be suspected of Mannian generation of bogus data. However, I don’t suspect every scientist of acting like the Hockey Team, and I don’t think we should have that level of distrust as a general rule. “Trust but verify,” yes, but not an automatic “You’ve buggered the data!”
Only the BBC article on the phytoplankton reduction points out that overfishing may be a more reasonable explanation FOR the reduction in phytoplankton — not the other way around. Specifically, the article suggests are now less fish to graze zooplankton, so there are more grazers OF phytoplankton (the zooplankton).
Here is the BBC article link:
http://www.bbc.co.uk/news/science-environment-10781621
Here is the part I found most interesting:
———–
“….Carl-Gustaf Lundin, head of the marine programme at the International Union for the Conservation of Nature (IUCN), suggested there could be other factors involved – notably the huge expansion in open-ocean fishing that has taken place over the century.
“Logically you would expect that as fishing has gone up, the amount of zooplankton would have risen – and that should have led to a decline in phytoplankton,” he told BBC News.
“So there’s something about fishing that hasn’t been factored into this analysis.”
———–
The overfishing hypothesis makes much more sense. I hadn’t realized it until reading the BBC account that zooplankton are major targets of many fish populations (yes, I verified, didn’t take the article on face value).
Take away fish, you get more zooplankton. If this happens, you get more zooplankton grazing on phytoplankton. Bingo!
Overfishing is very well accepted. Look at the collapses of New England and California fisheries in the past 40 years, and for a longer term perspective, read “Cod,” which explains that it has taken about 10 centuries to reduce what once was an incredibly abundant fish all over northern waters (one that when dried out, served as currency in 11th and 12th century Europe), to one which can no longer be fished, and can barely be found, on the East coast of the US and Canada. The Grand Banks off Nova Scotia used to be a prime fishing area for cod. It was so fished out by about 1990 that the Canadian government finally was able to institute a ban on fishing cod, so that hopefully they could come back. But they haven’t come back.
Open ocean fisheries have exploded in the last 50 years, with factory ships everywhere it seems at high latitudes. The growth in open ocean fishing by factory ship correlates well over 60 years with increases in CO2. So we have, perhaps, an excellent example of how correlation (in this case, CO2 increases with phytoplankton decreases) is NOT causation. The CO2 growth has a spurious correlation with the apparent actual cause, in this case the increase in overfishing (yes, this too needs to be verified, it isn’t demonstrated at this point — good science can take time).
A moral here is that scientists sometimes get things right – in my opinion, more often than not. They warned of collapses of fishing stocks for many years before the collapses actually happened. Fishermen only agreed to bans on fishing when they could barely find their target fish. And the bans in some cases have been very successful at bringing back the target fish — striped bass on the mid-Atlantic coast, for example.
Because much science in the end is accurate, it took me a long time to come to the reluctant conclusion that a lot of climate change science in various ways is “bent.” I was instantly suspicious of the conclusions of this article (climate change causes 40% reduction in phytoplankton!) because I’ve seen this movie, this hockey stick, this Himalayan glacier disappearance, this 50% reduction in North African rainfall by 2020 — I’ve seen this all before. And I found it laughable that with all the temperature cycling that has gone before, that phytoplankton are this sensitive.
That’s why I felt that the climate change explanation for phytoplankton decline was wrong, even if the 40% reduction was right (which still needs to be verified, it’s just one study). But I do buy the overfishing explanation, because it comports with science that has not been politically distorted, and which is accurate and has stood the test of time, in my view.
One commenter on the earlier WUWT article on this subject wondered why overfishing (which usually targets large species which no longer primarily eat zooplankton) would cause a zooplankton decline. Here is my response to his thoughtful question:
“Yes, it is correct that ocean fisheries usually target bigger fish, that no longer eat zooplankton. But we also target ever smaller fish populations — anchovies, sardines, menhadden — for fish oil supplements, and for feed for salmon and other farmed fish. And we also take in a lot of non-target fish (“bycatch”) and throw them overboard, dead. The smaller bycatch and the smaller target fish would be the ones more likely to eat zooplankton, wouldn’t you think?”
I am a geologist, not a marine biologist or oceanographer, but my discomfort with this Nature article is not quite due to its findings but to its presentation instead, that seems to have been carefully planned for profiting from the global warming scare machine.
First of all, it is quite uncommon that a still unfinished doctoral thesis gets such a notoriety, making headlines all over the world. In a public conference here in Rio de Janeiro last Thursday, one of the Brazilian “Nobel Prize” IPCC scientists waved the corresponding article which filled half the page of the Science section of the “O Globo” newspaper, as an unmistakable proof that Mankind is overheating the planet.
Second, it seems obvious that such a great global decrease in the phytoplankton stocks, even if confirmed by other studies, cannot be attributed to the tiny temperature changes observed in the oceanic temperatures since the middle 19th century (at least as the chief cause), as suggested by the main author in the press release. After all, during much of the Holocene epoch (since 12,000 years BP) the oceanic temperatures were quite higher than the current ones and before blaming them one ought to look for the evidences of such massive decreases during those warmer times (in the Lake Baikal in Eastern Siberia, phytoplankton generally thrived during the warmer periods).
Third, independently of the accuracy of his findings it seems that Mr Daniel Boyce is an adherent to the “Michael Mann” school of hiding his database and methods (by the way, first published in the pages of “Nature” magazine also).
So, let’s wait and see whether this is real science or just more warmist hype.
The experimental technique used in this paper is appropriate only for ocean waters. Coastal waters have many other sources of turbidity. But compared to inland and coastal waters, estuaries and upwellings, where the vast bulk of planckton activity takes place, the oceans are nutrient-poor deserts, of scant importance for the biosphere. Even if planckton were becoming still scarcer in the deep oceans, it wouldn’t much matter. However, if we did wish to increase ocean productivity (and fishing), we could do so by creating artificial upwellings; the temperature difference between the surface and abyssal waters is sufficient to drive Ocean Thermal Systems to power large floppy turbines pumping deep water to the surface. There’s no shortage of nutrients down there – just up in the photic zone.
In Science things change.
One day you get historical credit for showing your thoughts and calculations in a diary or in old letters to a freind that are found by someone a hundred years after your death.
On another day, you get credit for a three page paper published in an obscure quarterly that only 230 people in the whole wide world know anything about.
On another day, you get credit for saying something in a ‘public’ monthly or weekly that is ‘read’ by millions that happens to support an underlying prejudice of the day and which you naturally ‘include’ in your paper because you won’t be published without mentioning it, but which has no direct connection to your work, really, when everything is spread out a few years after you win your Nobel Prize; after all, what’s a little lie for the sake of science, at least you get published? Right?
If you want to play the game and win, ya’ gotta’ play by the rules –whatever the are when you’re playing.
Oops, I notice I’ve been mis-spelling plankton with a “c”. I wonder if that’s because I talk about Planck’s constant more than I talk about plankton? Sort of Freudian slip.
The biggest tell that this alleged study is garbage is this:
If the source of most of the biomass in the world was, as they allege, reduced by 50% then there would be dramatic and dangerous results in the food chain.
The major side effect of AGW belief is a reduction in intelligence of the true believer.
I think all this discussion is getting to the answer. Their numbers are a result of a combination of measurement problems: sunglasses and eyesight improvements; and less pollution fertilization. We would need to look at their raw data. One check would be to look at their numbers for locations where we know that recent fertilization has increased, such as at the mouth of the Mississippi river in the Gulf of Mexico.
Sorry, hit the post button too quickly.
Additionally, NASA satellites are showing that life on Earth- in the oceans and on land- is increasing.
Let’s see…rising temps reduce the amount of plankton, which means there’s less plankton to soak up CO2, whoa! Positive feedback loop! It’s WORSE THAN WE THOUGHT!!!!!!!!
It’s always “WORSE THAN WE THOUGHT!” Funny ain’t it, you’d expect sometimes things would move in a better than we thought direction wouldn’t you?
As for the lack of Gaian support for seeding the oceans, no surprise. I don’t have the exact quote in front of me, but one head weenie from one of the enviro groups once said that it’d be a catastrophe if we (meaning humans) discovered an abundant, cheap, non-polluting energy source because of what we’d do with it. Chew on that logic for a while, the only thing I can come up with is misanthropic.
Maybe things have changed since I took by Bachelor’s degree. But I seem to remember that the oceanic phototrophs were responsible for around 80% of O2 production. While I understand that a 50% drop in phototrophs wouldn’t yield a 50% decrease in atmospheric O2 levels we should see a measurable change in pO2. Where is that change?
Yada, yada.
What is the ACTUAL PERCENTAGE LOSS in the Mass of phytoplankton?
How many Tons/Pounds/Teaspoons/Grams/ have disappeared? What is the Percentage?
Median Density is a lousy metric for this subject.
Willis said:
So where did the Nature paper go wrong?
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The didn’t qualify their starting point. Everyone that talks about global warming knows you can show anything depending on where you start and stop the line.
Looks like there was a huge amount of volcanic dust in the air before 1900. Which is fertilizer for phyto.
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“While this might not seem like a large number, this translates into a decline of about 40 per cent since 1950”
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If someone wants to have some fun with this, use their own numbers against them.
Think adding iron to sequester CO2.
How much CO2 did they claim phyto can sequester?
How much CO2 would be released with a 40-50% reduction in phyto?
I would be willing to bet, using their own numbers, you would account for 100% of the increase in atmospheric CO2.
Gerard says:
August 1, 2010 at 1:07 am
Oxygen is a waste product from the earth’s living history. A 40% reduction in production at the end of only one century will not be measurable.
I think you are missing something. O2 is very reactive (which is why it is so useful for living creatures to extract energy). It is continually reacting with the environment. The primary form of degradation of most products is oxydation (combining with atmospheric O2).
The concentration of O2 in the atmosphere is not a result of millenia of accumulation, but a steady state, a balance between the rate it is being produced and the rate at which it is combining with various other elements to form oxides.
Stop the production and the concentration will fall very rapidly.
One problem with the method they used(with a disk). They tested the concentration at the top level of the ocean. What if the phytoplankton had a tendency to live in slightly deeper water because of some unknown factor? Possible factors to test would be: Amount of UV rays, ratio of deep water to surface water temperature, amount of CO2 in the water, salinity of the surface water, and probably many more factors. It always seems so easy to point global warming and end the research right there.
I haven’t read any of the comments yet, so this point may have already been made:
Out of curiosity, I clicked on the Google ad attached to this post (Highest Quality Pure Multi-Strain Phytoplankton (1 Bottle $29.95)) which stated:
“Marine Phytoplankton is considered to be one of the most powerful foods on Earth because it is loaded with high-energy super anti-oxidants, vitamins, minerals and proteins in microscopic form. It is a tiny little plant (about the size of a red blood cell) that naturally grows in the ocean and is the beginning of the food chain where as all other living creatures in the ocean feed on other living things that feed on this little plant. It is responsible for over 70% of the planet’s oxygen”
If 50% of the Phytoplankton is gone, has anyone noticed that 35% of the oxygen is gone?
Yup, comment #5 made this point about oxygen depletion.