Redfield Ratio Down For The Count

Redfield Ratio Down For The Count

Ocean science, as exemplified by the Redfield Ratio, is wrought with scientific theory that over the years has become dogma now shown to be flawed.

This ‘theory to dogma’ pathway in science while not exclusive to ocean sciences is too commonly found in the field. Theory become dogma  is regrettably common where the physical sciences meet the life sciences. All too often it is a device used by those characterized by personalities and egos that seek to simplify complexities of nature into mass appeal “sound bites.”

One such prominent ‘sound bites’ that is long overdue for the dustbin is the Redfield Ratio which is not only dogma but a ‘sound bite’ as well. When actual ocean pasture ecology observations are compared to the Redfield Ratio model they inevitably are dramatically mismatched.

Sound bites are mouth to mouth combat epigrams in the world of discourse, frequently cheap shots.  As human attention spans continues to shrink to the 156 character length of a Google ‘meta-description’, the density of  sound bite spam has become an cacophonous din. It’s bad enough when this happens in the discourse of politics or about which green vegetable is best, but it becomes the destroyer of scientific understanding and thought when only science that meets the brevity of a sound bite sees the light of day.

ALFRED CLARENCE REDFIELD was a member of a scientific family. His great grandfather, William C. Redfield, was the first president of the American Association for the Advancement of Science in 1848. Like most scientists in those days, he was an amateur.

RIP – ALFRED CLARENCE REDFIELD was a member of a scientific family. His great grandfather, William C. Redfield, was the first president of the American Association for the Advancement of Science in 1848. Like most scientists in those days, he was an amateur. (bio by Roger Revelle)

In this context Redfield some 80 years ago produced with the severely limited ocean science resources of that time a proposed ratio where the amount of biological material in ocean phyto-plankton must fit his stoichiometric ratio of  C:N:P = 106:16:1 – carbon, nitrogen, phosphorous.

Redfield being a chemist thought that this made perfect sense and until very recently his ratio has been described as an absolute rule, the holy of holies in ocean science, and of course also a “sound bite.”

So it has been proclaimed, taught, and been the basis for excommunication of those unwilling to live by the Redfield Rule that the simple chemical analysis of any volume of seawater for its nitrogen and phosphorous content would define the amount of carbon, read carbon to mean life, that would be possible.

This has resulted in ocean chemistry ruling the world of ocean science with an iron fist. (Though it seems that ‘iron’, the key pico-nutrient, has been their undoing.) The biological sciences were and are to this day relegated to relative obscurity their inherent complex, sound bite defying, complex science portrays. How dare they challenge the inviolate Redfield Chemical Rule.

But in the past decade a revolution has been hoving into view  in ocean science. The iron rule of the Queens of Science, physics and chemistry are being shown to be wholly inadequate to provide real insight into the living ocean. We now know that Life Finds A Way.

Take the role of nitrogen as a primary nutrient controlling photosynthesis and the production of new biomass. If the oceans are simplified to a chemists test tube then nitrogen that is in the ocean and new nitrogen that washes in from land become the only source of nitrogen to support plant growth. Thus vast regions of the world oceans have been classified according to the amount of nitrogen that is simply measured in water samples.

If a region is high in nitrogen then it has the potential for photosynthesis and phytoplankton growth. Nitrogen is simply the key ocean macro-nutrient. For every 16 units of nitrogen there is a potential for 106 units of  carbon based life to come into existence. If a high nitrogen sea doesn’t have lots of phyto-plankton then some other nutrient is limiting. Conversely a low nitrogen sea can never have lots of phyto-plankton. Or so says the Redfield ratio dogma.


Nitrogen fixing Tricodesmia are one of the most abundant life forms on this blue planet.

Nitrogen fixing Tricodesmia are one of the most abundant life forms on this blue planet.

Enter the notion of biological fixation of nitrogen by life. For decades it has been acknowledged in terrestrial ecosystems that vital life performing sustaining ecosystem service performed by “nitrogen-fixing bacteria” is key to plants on land.

In the oceans it has been barely a decade that the world of ocean science has discussed the notion that whereas the vast majority of life in the ocean is in fact cyano-bacteria, closely related to the ‘nitrogen fixing bacteria’ of land, those cyanobacters might just be performing the same vital ecosystem service at sea. Read more about ocean nitrogen fixation here.

Now we know that Redfield and generations of dutiful apostles of nitrogen being limited to what is seen to be merely chemically present in a water sample is a wildly inappropriate point of view. Life found a way to make available nitrogen to plant growth from the ever-present abundance of nitrogen in the air.

Next to nitrogen it has been thought that the most important nutrient in the oceans is phosphorous, so how about that phosphorous?

Redfield and his apostles maintain that phosphorous is really a truely limiting element to ocean plant growth. This is because phosphorous is not a constituent of air, like nitrogen, but rather a far more limited mineral element on this blue planet. Accordingly Redfield’s 80-year-old dogma can still stand up against the heresies  of life scientists. And it seemed this might be the case but very recently we have come to know that once again Life found a way. Read more about ocean phosphorous here.

Sargasso Sea Recycles Phosphorous

Sargasso Sea Recycles Phosphorous

Phosphorous being so very critical in the ocean ecology is surely limiting but it seems that the solution Mother Nature has worked out is the means to efficiently biologically recycle phosphorous.

This discovery suddenly has amplified the available phosphorous dramatically such that the Chemical Queen can no longer make her claim to being all-knowing and demanding of fealty. The ocean is not some simple test tube vial of liquid that may be reduced to first year chemistry sound bites.

The ocean is a rich living broth of incredible complexity that has found ways to take care of itself through recycling of critical constituents through the nearly indescribable complexity of the interactions and relationship of millions of forms of life. By dumbing down the complexity to where the simplest solution is believed to be the most correct we doom ourselves to misunderstanding and mismanagement.

Today with the two tenets of Redfield having been so resoundingly shown to be misleading sound bites it is time to bid adieu to Redfield, his apostles, and minions. Yes this will discredit countless ocean science theses and publication and that will be painful and resisted by those whose claim to fame and privilege but it must be done.

Let the mouth to mouth combat begin!