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.
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Oh, BTW my statement that Phytoplankton levels have risen come from here:
“Gregg and his colleagues published their new study in a recent issue of Geophysical Research Letters. The researchers used NASA satellite data from 1998 to 2003 to show that phytoplankton amounts have increased globally by more than 4 percent.”
from
http://www.nasa.gov/centers/goddard/news/topstory/chlorophyll.html
I got the link from the other Plankton thread.
I think Larry Fields should be barred after that atrocious pun. 😉
Major reason for decline of fish:
1) Too many whales
2) Too many sharks
3) Too many seals
Whales, sharks and seals, now protected, are at the top of the food chain. Each of their numbers is at record highs. One sperm whale can eat 3/4 ton of herring in one bite. Many other whales and sharks are sieve feeders and grow to enormous sizes (e.g. basking shark, whale shark, baleen whales). Predatory sharks are at all time highs, being seen in huge (dangerous) numbers everywhere. Seals prefer menhaden, herring, and the like, all of which are also favorite foods of our favorite food fish (e.g. tuna, mackerel) and game fish (e.g. sailfish, tarpon).
Why do we not begin to cull our competitors at the top of the food chain? Plain foolishness, if you ask me, that we do not.
We are just noticing populations of those particular edible fish that we, but also the predators mentioned that are proliferating unchecked, prefer.
Sean Peaks:
Sharks have been drastically reduced world wide, mainly due to the oriental demand for shark fin soup. Most whale populations are still far below levels when whaling was at it’s peak in the 1800s. I’m not sure about seals. They eat alot of fish in near shore waters but would have no effect in the open oceans. Marine biologist are especially concerned about sharks, which have reached the lowest abundance since the begining of fisheries data. Try a search in google or better, google sholar on shark populations.
bubbagyro says:
August 1, 2010 at 4:42 pm
“Why do we not begin to cull our competitors at the top of the food chain? Plain foolishness, if you ask me, that we do not.”
There would be a few unintended albeit predictable consequences. Here’s an example of one that’s already happened. The cougar is *locally* extinct in parts of New England, in which Lyme Disease is a public health problem. Coincidence you say? Hardly. The local deer are a part of the life cycle of the tick that carries LD, and they’re also an ice-cream species for cougars. The demise of the cougars there has contributed to the increased deer population, which in turn is fostering LD.
Reintroducing the cougar would decrease the incidence of LD. If all adults hiking in the woods there traveled carried in pairs and carried sidearms, cougar-related human fatalities would be minimal to non-existent. It would also be helpful to avoid mountain-biking and jogging, both of which activate the prey drive in cougars.
The big picture there is that reintroduced cougars plus a few supplementary common-sense measures would prove to be beneficial for the public health of New Englanders. I wouldn’t call that foolishness.
An alternative approach: Shooting more deer would have a similar effect.
Mike says:
August 1, 2010 at 3:28 pm
This study adds weight to the claim that we should take action to limit GHG emissions, but no one result determines where the balance of evidence lies.
======================================================
No it doesn’t Mike.
It only shows that plankton needs more nutrients and that the oceans are getting nutrient poor and will not support the same amount of plankton it supported 100 years ago.
Prior to there measurements in 1900:
There were 8 major volcano eruptions, with a DVI – Dust Veil Index – of over 300.
And over 20 eruptions with a DVI of 100 – 300
Krakatoa was 1883 and had a unbelievable DVI of 500
Eruptions put iron and other fertilizer in the oceans for plankton.
All they did was start their measurement when plankton levels were at their highest, because of the recent volcanoes.
Here’s the volcano dust index for that time period:
http://rankexploits.com/musings/wp-content/uploads/2008/01/histvolcanoerup.jpg
As the ice sheets retreated say 15,000 years ago there were large
expanses of rock flour exposed. Much of this was deposited elsewhere as
loess. Much however would have been blown into the oceans to fertilize
them. This would have resulted in an increase in the microphyta
followed by increases in everything else up the food chain. Much more
recently poor agricultural practices, in the USA particularly, led to
dustbowl conditions and, one might reasonably expect, further
fertilization of the oceans. Perhaps a reduction in ocean microphyta,
if indeed there is any, might simply be due to recent improvements in
agricultural practices and soil conservation.
BillD says:
August 1, 2010 at 5:27 pm
Not true. Forget Google. Read the fishing reports. Whales are at 50 year measured highs (except for sources like Greenpeace, ADF, etc. – and we know how that goes). They did not have accurate reporting before then. Whales are everywhere, Minkes, Killers, Sperm, Pilot, and all others all over the Great Banks. Whale watch boats never fail a day from New England ports to spot whales. live near the Gulf of Maine and go out 50 miles to fish for cod and tuna (and the shark derby). You cannot hook one tuna for every 5 sharks. My son in law hooked a Great White out 30 miles. Mako, Lemon, all kinds. Great Whites are everywhere, even coming in to Cape Cod recently. Even the grey whale is showing up in southern waters. In Florida, where I also live, every shark, especially Hammerhead, Reef, and Bull, is more noticeable even in the last ten years.
As for deer ticks and LD, that is an absurd stretch, Larry. I lived in PA which has the healthiest deer and the most hunters. No Lyme. Hunters take the place of the cats and wolves, although coyotes are a scourge now in PA as hunting has declined, so perhaps Lyme will surface there. Coyotes are a scourge in New England now, and take huge amounts of deer, more than cats or canines ever had. Lyme disease is a very low percentage disease, not to be cited as a calamity (except for the few that get it). Lyme was not even discovered until recent decades, so people who got it lumped it in with all other “wasting diseases” of the past centuries.
Don’t believe everything you read. That is the gist of WUWT, our eyes are opening to what the Greenies and Gaia worshippers are spouting, so that one should keep an open mind and let the debate sort things out. Although from some comments, it may be a lost cause.
“The earth’s human population increased about 400% since the late 1900s.”
Late 1800’s I would buy, not late 1900’s.
For a refreshing and, quite frankly, stunning interpretation of the natural variability inherent between climate and ocean, phyto- and zooplankton abundance and fish productivity, I recommend reading, “Cyclic Climate Changes and Fish Productivity”, by L.B. Klyashtorin and A.A. Lyubishin. Originally in Russian, later translated into English in 2007, it throws the book (pun?!) at much conventional thinking. It’s big at 226pp, or below as a 2.78MB pdf:
http://narod.yandex.ru/100.xhtml?alexylyubishin.narod.ru/Climate_Changes_and_
Fish_Productivity.pdf
The translator is Dr. G.D. Sharp (formerly IPCC) who abandoned after the 2nd Report citing, I believe, misuse of data etc. and no lover of GCM’s.
Roger Dewhurst says:
August 1, 2010 at 6:18 pm
==============================
Excellent points Roger.
Talking about the dust bowl, reminded me of African/Saharan/dust, that’s the main driver for the Caribbean.
Since it’s obvious it has nothing to do with ocean temperatures, and everything to do with fertilizer, I’d like find something on historic African dust events.
“University of Queensland’s Dr Michael Noad, who heads the East Coast Australian Humpback Whale Population survey, says about 100 whales a day are passing through.
“In the last survey (in 2007) the whale numbers weren’t as big. The biggest day was 130 whales with 70 whales a day being the average,” Dr Noad said.
“At the moment our guys are seeing 100 whales a day consistently.”
Dr Noad said he expected 13,000 humpbacks in Queensland waters this year, which would be about a 10 or 11 per cent increase on the 2007 figures.”
From July 24:
“It’s very unusual in terms of just the sheer number of animals,” said Daniel Palacios, a Monterey oceanographer with the National Oceanic and Atmospheric Administration. “The bay is abuzz.”
Passengers aboard the Sea Wolf II, operated by Monterey Bay Whale Watch, saw this abundance on Thursday. In a three-hour tour, they saw 80 humpback whales, 400 Risso’s dolphins and 150 northern right whale dolphins.”
From Oregon this winter:
““It was the highest visitor count in five years, and the highest number of whales spotted in five years,” said Morris Grover, head of the Whale Watch Center in Depoe Bay.
Morris Grover at a spring Whale Watch Week in Nye Beach.
Under the aegis of Oregon Parks and Recreation Department, the Whale Watching Spoken Here program has been in existence for 33 years now, Grover said. This past Whale Watch Week yielded some major records, as volunteers stood on overlooks across the Oregon coast’s 364 miles for four hours a day and helped visitors spot the giant watery beasts.
“The whale count set an alltime record,”Grover said. “Now, we don’t even have quite all the data in yet, as a few stations haven’t submitted their paperwork yet. But so far, the whale count was 672, and we had 9,134 people come by.”
From Gulf of Maine last winter:
“We’re excited because seeing 44 right whales together in the Gulf of Maine is a record for the winter months, when daily observations of three to five animals are much more common,” said Tim Cole, who heads the team. “Right whales are baleen whales, and in the winter spend a lot of time diving for food deep in the water column. Seeing so many of them at the surface when we are flying over an area is a bit of luck.”
Published Aug. 16, 2009
Previously rare in local waters, world’s largest fish recently spotted with frequency off Alabama coast: In other years, scientists said, multiple sightings of whale sharks off Alabama would have been so rare as to be almost unbelievable. But in 2009, the Alabama coast became one of the best places in the world to see the ocean’s largest fish, with dozens of sightings reported to a whale shark Web site by fishermen, scuba divers and pilots.
Link got fried. Try:
http://narod.yandex.ru/100.xhtml?alexylyubishin.narod.ru/Climate_Changes_and_Fish_Productivity.pdf
Larry Fields says:
August 1, 2010 at 5:43 pm
bubbagyro says:
August 1, 2010 at 4:42 pm
“Why do we not begin to cull our competitors at the top of the food chain? Plain foolishness, if you ask me, that we do not.”
There would be a few unintended albeit predictable consequences. Here’s an example of one that’s already happened. The cougar is *locally* extinct in parts of New England, in which Lyme Disease is a public health problem. Coincidence you say? Hardly. The local deer are a part of the life cycle of the tick that carries LD, and they’re also an ice-cream species for cougars. The demise of the cougars there has contributed to the increased deer population, which in turn is fostering LD….
______________________________________________________
First the cougar seems to be back in New England: http://www.mountainlion.org/newsroom_article.asp?news_id=826
In North Carolina there are “officially” no cougar despite plenty of sitings and photos. My neighbor has a wild life camera and caught a picture of one. My husband nearly hit one with the truck… it was black. (Saw a bald eagle for the first time in the wild last week near Jordan Lake) http://mountainlion.org/forum/topic.asp?TOPIC_ID=19
http://www.fieldandstream.com/forums/campfire/mountain-lions-east-coast
Given the problems with attacks on people out west, I think the officials know darn well the cats are here and are keeping their mouths shut. There is an “official” population of about 100 in Florida. They are solitary with a range up to 370 sq miles and can travel as much as 30+ miles in a night. A young male cougar ( radio collared) traveled over five states. “Mountain lions dispersing into the Midwest have been known to travel hundreds of miles.” http://www.mountainlion.org/newsroom.asp
Here in North Carolina Rocky Mtn fever from ticks has been bad. Two friends and a neighbor had it and hubby was comatose for ten days from it.
Has research from the 2004 SeaWiFS instrument aboard the Seastar satellite study been debunked? If not, I’d sure like to know how the researchers for this new ‘phytoplankton have radically decreased’ square their data, results, and conclusions with that of the satellite data which showed:
Its awfully hard to imagine two sets of research with more contradictory results.
This was from an article “In Praise of CO2” June 2008 by Laurence Soloman: http://www.financialpost.com/story.html?id=569586
and posted on WUWT by Anthony with the subject: Surprise: Earths’ Biosphere is Booming, Satellite Data Suggests CO2 the Cause
http://wattsupwiththat.com/2008/06/08/surprise-earths-biosphere-is-booming-co2-the-cause/
#
#
latitude says:
August 1, 2010 at 7:43 pm
Roger Dewhurst says:
August 1, 2010 at 6:18 pm
==============================
Excellent points Roger.
Talking about the dust bowl, reminded me of African/Saharan/dust, that’s the main driver for the Caribbean.
Since it’s obvious it has nothing to do with ocean temperatures, and everything to do with fertilizer, I’d like find something on historic African dust events.
_______________________________________________
The dust bowl in the USA certainly had to have an effect. I wonder if there are dust records available from the ice cores. I remember reading a comment that connected dust amounts to the ice cores, I think it was in relation to percipitation.
I just googled and got a BIG surprise!
Study of Dust in Ice Cores Shows Volcanic Eruptions Interfere with the Effect of Sunspots on Global Climate
Seems Sunspots DO correlate with climate…. Unless volcanic action interferes according to this study of dust in Greenland ice cores, sunspots, and volcanoes.
“The research, published in a paper in the May 15 [2002] issue of Geophysical Research Letters, provides striking evidence that sunspots — blemishes on the sun’s surface indicating strong solar activity — do influence global climate change, but that explosive volcanic eruptions on Earth can completely reverse those influences.
It is the first time that volcanic eruptions have been identified as the atmospheric event responsible for the sudden and baffling reversals that scientists have seen in correlations between sunspots and climate…
“By carefully studying the timing of other volcanic eruptions, we found that they coincided with all of the correlation reversals between sunspots and climate,” said Ram.
A chart in the paper shows how six major volcanic eruptions between 1800 and 1962 occurred during precisely the same years when there were reversals in the correlation between sunspot activity and climate….
According to Donarummo, it long has been known that volcanoes add more dust and more sulfates to the atmosphere.
The UB team discovered that these additional sulfates cause cosmic rays to have a more pronounced effect on Earth by spurring the formation of small droplets in the atmosphere that, in turn, cause the formation of a type of cloud that does not produce rain.
“During these times of high volcanic activity, the sunspot/climate correlation reverses and dust levels rise, even in the absence of high sunspots,” explained Stolz. “
Willis,
I actually find your arguments to have merit– though I do tend to believe that plankton have declined as the study suggests. They have a lot of data points and their methodology is sound.
I would ask you to consider this question: Suppose they are correct? Plankton of course play a vital role in many aspects of the biosphere’s regulation of food supply as well as climate feedbacks. I would like you to put your considerable scientific skills to work on playing “what if” for a moment, suspending your disbelief in this study, and giving an opinion about what it might mean if plankton are indeed in decline.
In two of the last three years we have had blooms of red tide plankton both in the Gulf of Mexico twice and in New England once. The extensive blooms were furious and made life miserable. In the ten years before that, we had none.
I don’t know where these dudes were sampling, but shoreward they were very healthy populations. The causes were not known, but were attributed without proof to excessive nutrients.
Kum Dollison says:
August 1, 2010 at 4:11 pm
On a dataset the size of the one in question, if the median drops by half, the mean will drop by about half as well. What this means is that the total mass will drop by half.
Willis,
I sleep better knowing you are out there checking out these alarmist studies. Do you sleep at all? It’s all I can do to read a few papers a month and skim through a few blogs.
Hopefully your diligent and cheerful efforts will inform more and more rational people to investigate more and more of these dubious studies until the tide is turned.
Willis Eschenbach says:
August 1, 2010 at 11:52 pm
“On a dataset the size of the one in question, if the median drops by half, the mean will drop by about half as well. What this means is that the total mass will drop by half.”
Not when the distribution is highly skewed! Most of the mass of plankton comes in a small fraction of the area. Concentrations in nutrient-rich coastal waters can be many orders of magnitude higher than throughout the nutrient-poor oceans. So the median is far far below the mean, and changes in the median (that is, changes in ocean waters) have next to no effect on the total (which can only be significantly changed by changes in the areas of high concentration).
Thank you, Paul. You explained it very well. I kept thinking they would catch on after awhile.
“If you spread a shipload of rust (iron oxide) out into the tropical ocean, you generally get an immediate bloom of phytoplankton.”
I read that and then watched the animated gif. I wonder how the plankton correlates to the major shipping channels. it’s probably nothing but a passing thought but there it is.
Kirly says:
August 2, 2010 at 8:38 am
Good thought. However, even though we are talking about a trace element requirement for iron, this still needs hundreds, or thousands or more tons of iron when we consider the huge size of the oceans.
crosspatch says:
August 1, 2010 at 7:18 pm
“The earth’s human population increased about 400% since the late 1900s.”
Late 1800′s I would buy, not late 1900′s.
Crosspatch:
You are 100% correct. I meant to type “late 1800s” and not late 1900s. I hope that most people would have figured out the mistake. Man’s effects on the environment are related to total population and energy use, and both of these factors have drastically increased since the turn of the 20th century. It’s true that we have made some progress in reducing the amounts of pollution in terms of pollution/$GDP, but not enough to offset great increases in population and exploitation.