A O U
Food Chain

Nifty graphic of the food chain (280k)
(Graphic originally appeared at Doctor Sharp's site on Monterey.Edu in Ca.)

The Food Pyramid

We've all heard the term Food Chain. Most of us learned this term in the classroom as kids. What follows is my interpretation of the Food Chain as regard the stock reductions in many (if not all) fisheries. Let's take a look at how it works:
Apex Predators feed on Piscivores
Piscivores feed on Planktivores
Planktivores feed on ZooPlankton
ZooPlankton feed on Macrophytes
Macrophytes feed on Algae
Algae feed on PicoPlankton
PicoPlankton feed on Bacteria
Bacteria (the lowest form of life) form from Nutrients
Nutrients are an exquisitely precise extraordinarily intricate complex of nanoscopic (sub microscopic) chemical reactions interacting to combine and create bacteria.

These chemical reactions are interdependent on light, water temperature, water chemistry, ... a whole host of conditions have to be just right for them to take place.

Now the steps in the chain are not rigidly adhered to; that is - there are probably a whole host of crossovers taking place all the time.

An Apex Predator (of which Man is only one) is clearly dependent on everything below. There used to be a "rule of thumb" thinking there was a 10 to 1 ratio in each step. (That is: it took 10 units of Piscivore to support one unit of Apex Predator. Now that surely isn't an exact ratio but it gives an idea of dependencies.)

Now using the 10/1 ration (it's convenient) it means that for each unit of Apex Predator there must be 100,000,000 (100 million) units of exquisitely precise extraordinarily intricate complex of nanoscopic chemical reactions interacting first to support one unit of Apex Predator.

Next take into consideration the Absolutely Astonishing Amount of man made particulate that goes in the ocean every year. The numbers in my PARC paper {1} indicate that conservatively for each 40 gallons of rain that falls, 1 pound of particulate washes into the ocean in some form or another. (If you find that figure unbelievable, and I do, you can do your own test. Put a white food platter outside. Let it get rained on and then let the water evaporate. Almost invariably, at least here on the East Coast, it will leave a residue of black particulate.)

Now if that particulate inhibits or alters the exquisitely precise extraordinarily intricate complex of nanoscopic chemical reactions/interactions (and it will, it has to), it's not hard to see how populations above it will be negatively affected.


References
{1} PARC A paper documenting the Absolutely Astonishing Amount of man made particulate that goes in the ocean every year.

{2} Rethinking Fisheries Management The most excellent graphic and the terms in the chain (except for the Nutrient level. That was (ahem) mine.


(Note -I have received a couple notes from Dr. Sharp and another biologist. I'm posting them here for clarity's sake.)

Vindication ,Good
Comments-,Hi,

I think that you missed several points about the messages in Its About Time, etc... by G.D. Sharp, that was published in the Procedings of the Second World Fisheries Congress. One is that I am MUCH MORE Conservative than you pretend to be.

The messaages that Dr. Sharp has been carrying around the world are that there is a real Fisheries System, and it includes all time and space scales, as they pertain to understanding the natural and HUMAN impacts on the balance between people and truly functional ecosystems. Humans have already manipulated them enough to know that they can - and do - extinct species, and as such, fisheries management was a latecomer in the fray for maintaining needed support systems. It is quickly becoming too late, for many components of the global aquatic ecosystem, as people swarm over key habitats, poison their environments, and flush everything downstream for the next victims to enjoy. The science community has been so busy coiled around the funding sources that the problem has outrun them... Analogy: The drunk searching for the dropped keys under the streetlight when they were dropped in the dark around the corner... What does not make any sense is trying to blame any one thing, process or sector for the failures of humanity to make intelligent, self sustaining decisions.

Greed, Short Term Profit Taking, and DENIAL are the basic human traits, paperboys, bankers, on through fishers and farmers, that make this generations decisions key to the very survival of humankind. Quit looking for whipping boys, and start looking at serious, long-term solutions about how to 1) Slow and then reverse human population expansion; 2) Recoup or rehabilitate critical ecosystem functions (habitat, processes, genetic resilience, etc.); and put a lock on the policies and procedures such that humans get aligned with their finite, slowly running down universe!!!

g sharp

Dr. Sharp apparently believes the ocean system is magnitudes more complex than any (especially the simplistic solutions of fishery "scientists") are giving credit it to. A point I too have been making for more than 20 years, though with sharply less credibility. (sorry I just couldn't resist{g})

I don't doubt we have other serious problems besides particulate pollution but it's clearly a problem of great magnitude and one that can be dealt relatively easily and cheaply as far as the United States is concerned. That I don't grasp the scope of the time scales as Dr. Sharp does (I suspect that few do) doesn't detract from my position.

I do have to say that attributing greed and denial to me is a rather cheap shot. I would have expected better than a knee jerk reaction from someone of such apparently formidable intellect.. It is however typical of those in fisheries research to view themselves as the last good guys. It somehow eases their conscious when they pull their own fast ones ("Ends justify the means and all that") when they can denigrate the users. ("They had it coming.")


Food Chain ,JustOkay
Comments-,Hi,

You have added in a few apples and prunes where there should be bananas. Algae, Macrophytes, and some large proportion of picoplankton are plants. They don't "eat" they just create biomass from nutrients.

Picoplankton and bacteria are puzzling, in that they mey not do anything except clean up after the messy eaters, or one another. The trusty Rule of Thumb is that there are 5 trophic levels, each doing somewhat as you have put into play. Meaning 1 unit of Apex Predator represents about 100 thousand units of primary production, presuming that they only eat one level below themselves.

Tunas, and other large fishes often filter feed, as well as gobbling down fishes, making them somewhat better adapted to oceanic systems, where the next fish that you encounter may be your own species, or close...

Yellowfin tuna in the eastern Pacific: another small thunnid comprises about half the diet. By catching 200,000 tons of Yellowfin each year, there are about 2 million tons of the other species left behind, to gobble down what might have been shared amongst small yellowfin. Think about it.

Cheers,
g sharp

I have taken a few liberties with the food chain above but it doesn't alter the basic premise. It's not my bailiwick to teach biology here, just to give a feel for the complexity of it and just how the astonishing amount of particulate that ends up in the ocean can upset major portions of it and in ways not readily visible. We can all see an oil spill but can we see when hydro sulfides (or whatever) interfere with the formation of algae (or bacteria or whatever) reducing all above it that depended on it to prosper.


Food Chain ,Good
Comments-,Gosta,

"Macrophytes", in the sea, are mostly algae and both of those are plants. They make food from sunlight and nutrients. (Sunlight isn't normally counted as a nutrient.)

Some picoplankton (and nanoplankton) and bacteria make their food as plants but I think others live off detritus -- bits of broken down plants and animals, plus all the stuff they release into the water.

So the apex predators are about level 5, not level 10. (The highest number used in ecosystem modelling seems to be 4.6 but big individuals of the apex species might average 5.5, so 5 sounds good.)

The 1:10 business works on land with warm-blooded animals. In the sea, the ratio for biomass (weight alive at any one time) is about 1:1. However, the bigger animals live longer, so the ratio for production (amount of new material produced in a year) is higher. However, it isn't 1:10. Maybe 1:5.

So one ton of marine apex predator is supported by one ton of plants, but each new ton of apex predator needs about 250 new tons of plants.

Those plants are mostly very small. So one new seal may mean the deaths of huge numbers of tiny green plants, but that's a part of the calculations that you haven't included.

Again this is not intended to be a biology reference page for students to reference in their studies. It's intended to be a place where a little light can be shed on a serious issue for the great ignorant masses (as we're viewed) out there. Precision accuracy is less important than concept.


(Note - Sent on by a surfer)

Food Chain ,Good

  • Comments-,"detrius" includes the decomposing remains of everything that dies in in the system (or washes into it) from plankton and herring to some of my old friends and/or shipmates. The low end of the chain is partly replenished from the "higher" levels, making sort of a "food cycle", albiet kinda egg-shaped.

    Tom Pittman pittman@ptialaska.net



End of Food Chain


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