Phytoplankton, the plants at the base of the food chain


Phytoplankton, the plants at the base of the food chain, are constantly decreasing in the oceans

August 27, 2010

The news should be of great concern because we are talking about Phytoplankton, that is to say of those vegetable organisms of very small dimensions (a few thousandths of a millimeter) which are nothing but algae able to perform, thanks to the energy supplied by the sun, chlorophyll photosynthesis , i.e. the transformation of inorganic compounds such as water and carbon dioxide into organic elements such as glucose, a basic element from which, through various chemical reactions that take place inside the cell, we arrive at the synthesis of all organic compounds that characterize living beings. In practice we speak of the dentists of the survival of all animal organisms, including man.

Daniel G. Boyce, Boris Worm and Marlon R. Lewis researchers from the Dalhousie University in Canada (2), have studied and elaborated measurements from 1899 to today, in order to have a complete picture of the state of phytoplankton concentration. The results obtained were disconcerting: they showed a decrease of about 40% compared to 1950 with a constant decrease of about 1% per year.

"Phytoplankton provides food for virtually the entire ecosystem, from fish to humans," says Dr. Boyce and goes on to say that "Phytoplankton is also important for maintaining sustainable fishing activities and the overall health of the sea. We must ensure that it does not continue to decline" because it ultimately constitutes about half of all plant organisms on our planet. .

The cause of this decrease hypothesized by the researchers is the increase in the temperature of the oceans as it was observed that the greatest drops were recorded where the waters had undergone greater temperature increases and this is explained by the fact that more hot limits the amount of nutrients that could be exploited by the phytoplankton for its survival.


  1. Original photograph courtesy NASA
  2. The news was published by Dalhousie University; while the full study The global decrease of phytoplankton in the last century you can find it in the magazineNature dated 29/07/2010 or whose authors are Daniel G. Boyce, E Boris Worm both of the Department of Biology of the Dalhousie University, Halifax, Nova Scotia (Canada) and Marlon R. Lewis of the Department of Oceanography of the Dalhousie University, Halifax , Nova Scotia (Canada).

A living being feeds on what precedes it in the food chain and, in turn, is eaten by the next, which can be another animal or a human.

The food chain has a pyramidal structure divided into various trophic levels to each of which correspond specific categories of living beings.


The largest category you can find at the base of any food chain. Producers are autotrophic organisms, able to organize chemical compounds in the soil (or water), to independently produce food reserves (sugars, starch). This process can take place thanks to the energy provided by the chlorophyll photosynthesis.


They are heterotrophic organisms that, in order to feed themselves, need to eat other organisms. We can distinguish:

  • the herbivoresthat feed directly on the producers: deer, rabbit, gazelle, grasshopper, zebra, elephant etc ...
  • the carnivores that feed on herbivores: fox, hawk, dolphin, spider, lizard etc ...
  • the carnivores that feed on both herbivores and other carnivores: lion, leopard, tiger, killer whale, wolf, crocodile, eagle etc….

A species can occupy multiple levels depending on the food energy source it feeds on. Omnivores, in fact, do not occupy a fixed level, but vary it according to what they eat.

Decomposers or transformers

Generally they are i bacteria which decompose the remains - animals and plants - into substances that can be reused by producers. Their role is fundamental because they determine the decomposition of organic matter and remineralize the nutrients (nitrogen is phosphorus first of all) which are reused by manufacturers.

Phytoplankton, the plants at the base of the food chain

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A study by the Canadian University of Dalhousie states that the microscopic plant organisms that live in suspension in the sea are decreasing at an average rate of 1% per year, probably due to global warming. This phenomenon threatens the marine food chain, as phytoplankton is at the base of the food chain and represents a nourishment both for the tiny organisms of zooplankton, both for large marine mammals such as whales, and for most of the fish.

According to the research team, phytoplankton is the fuel of the marine ecosystem and its decline affects the entire food chain, including humans. In fact, vegetable plankton produces half of the oxygen we breathe, reduces CO2 and is important for fishing.


since 1950 in the northern hemisphere alone, plant plankton has experienced a 40% decrease
Scientists have established a correlation between declining phytoplankton and rising sea surface temperatures

Can the Commission say what programs it intends to promote in order to combat global warming?

The food pyramid (1)

Light, phytoplankton, nutrients, herbivorous organisms, carnivorous organisms, decomposing bacteria… They are all essential elements of the so-called food pyramid. Let's see how it is made and how it works.

"Big fish eat small fish". How many times have we heard and used this maxim that summarizes what is scientifically called the "food pyramid"! But what is at the base of the pyramid? What is your first step? What is the smallest fish that sets off the chain of prey and predators? In reality, at the base of the food chain there is not a small fish, since exactly what is observed in dry conditions happens underwater, where grass is at the very top of the nutrition chain, there are plants. Underwater it is the same thing: at the first step of the food pyramid there are plant organisms: in particular phytoplankton, which, let us remember, is the vegetable part of plankton.

Vegetables grow in quantity thanks to chlorophyll photosynthesis, so the basis of life and its production levels is sunlight. The first level of production, therefore, derives directly from light and is called, in fact, "primary production". If you look for the definition of primary production in a biology text, you will read that this is "the photosynthetic and chemosynthetic transformation rate of light energy into organic matter in the form of biomass". Let's dissect this definition and translate it in a simpler way: photosynthesis is the process by which, starting from water and carbon dioxide (CO2), thanks to light energy, plants produce glucose for their own nutrition and oxygen. Thanks to nourishment, plant organisms grow and multiply (increase in biomass), thus offering a sort of pasture to herbivorous organisms. The latter constitute the second step of the food pyramid and are defined as primary consumers. In the world of the sea, herbivores are represented especially by huge aggregations of tiny crustaceans (belonging to zooplankton, the animal part of plankton)), including the so-called copepods and, in Antarctica, the famous krill, schools of millions and millions of tiny shrimps that, for example, whales eat.

Herbivores are the food of the first carnivores (secondary consumers), usually small fish, and these will be eaten by larger fish, up to the apex of the chain, where we can place the shark.

Secondary production

We have said that when, thanks to chlorophyll photosynthesis, phytoplankton produces other phytoplankton, there is primary production (in practice, plants produce other plant tissue). When, on the other hand, herbivorous crustaceans, eating phytoplankton, produce other animal organisms, there is a so-called secondary production (animals, by feeding, produce other animal tissue). Now let's compose a simple food chain, considering, in sequence, phytoplankton, herbivorous organisms, an anchovy, a mullet, a bluefish and a shark. In order: phytoplankton is eaten by herbivores, herbivores are eaten by anchovy, anchovy is eaten by mullet, mullet is eaten by bluefish and bluefish is eaten by shark.

From a quantitative yield point of view, 100 grams of phytoplankton yields 10 grams of herbivorous organism tissue, 10 grams of herbivorous organism tissue yields 1 gram of anchovy tissue, 1 gram of anchovy tissue yields 0.1 grams of mullet tissue. , 0.1 grams of mullet tissue produces 0.01 grams of greenhouse fish tissue and 0.01 grams of greenhouse fish tissue produces 0.001 grams of shark tissue. In summary, each step of the food pyramid uses only 10 percent of the resources of the previous step.

The two-compartment ocean

In oceanography, the sea in a broad sense is defined as an ocean: the various geographical boundaries are not taken into account and it is considered "the world ocean". This is divided into two compartments: the upper compartment, which goes from the surface up to 150-200 meters deep, and the lower compartment, from 150-200 meters to the bottom. Between the two compartments (or layers) there is a clear dividing element, called the thermocline. The thermocline is a band of water in which a drastic drop in temperature is observed and, consequently, a higher density, since the colder the water, the denser it is, but keep in mind that density is synonymous with weight. Therefore, to say that cold water is denser than hot water means that it is heavier. This clarification is important because in common speech we usually use the term density to indicate viscosity. According to exact terminology, therefore, oil is less dense than water (because it is lighter) but more viscous. Let's go back, however, to talk about the thermocline. In the ocean there is a permanent thermocline, which divides the two compartments, but there are also other thermoclines, which are formed according to the seasons, called, in fact, seasonal thermoclines. Under normal conditions, in the Mediterranean, in April, a thermocline is observed at a depth of 15 meters, which lowers the water temperature from 14 to 4.5 degrees. From June to the end of August, however, at a depth of 20 meters there is a thermocline that brings the temperature from 22 to 4 degrees.

[The food pyramid (1) continues]

Dr. Adriano Madonna, Marine Biologist, ECLab Laboratory of Comparative Endocrinology, University of Naples "Federico II"

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Phytoplankton, the plants at the base of the food chain

Phytoplankton is made up of tiny plant organisms carried by sea currents. The existence of phytoplankton is essential for all life forms on our planet because without it, life on Earth as we know it would never have developed or ceased to exist. One teaspoon of seawater can contain up to one million single-celled plant organisms. Some interesting data:

  • The phytoplankton on our planet produces about half the oxygen we breathe
  • Over 99.9% of all carbon dioxide incorporated by living organisms during geological eras is buried in marine sediments and this is largely due to phytoplankton
  • Phytoplankton is at the base of the marine food chain and therefore provides sustenance for almost all life forms in the oceans.

Satellite images are extremely useful for obtaining information on the quantity of phytoplankton, its distribution and its modifications over time and space. The different colors of the water reveal the presence and concentration of phytoplankton, sediments and dissolved organic chemicals. The more phytoplankton there is, the greener the water color. Where phytoplankton is scarcer, the water is bluer. Phytoplankton contains the chemical chlorophyll that makes photosynthesis possible, i.e. the production of organic substances in the presence of sunlight. Because different types of phytoplankton contain different concentrations of chlorophyll, they appear different colors to sensitive satellite instruments. By observing the color of an area of ​​the ocean, one can estimate the prevailing quantity and type of phytoplankton in that area and obtain information on the health and chemical composition of the sea. By comparing the images recorded at different times, you can get information on the changes that occur over time.

The color of the ocean can also be useful for interpreting the phenomena of El NiГ ± o and La NiГ ± a. Scientists are able to observe the biological response of the Pacific Ocean to the alternation of these two major ocean / atmospheric events. The equatorial Pacific passes from the condition of El NiГ ± o, poor in nutrients and phytoplankton, to the condition of La NiГ ± a, rich in nutrients and phytoplankton.

We will now analyze the El NiГ ± o event of 2006-2007 and the subsequent La NiГ ± a event of 2007. In early 2006, after strong westerly winds, positive sea surface temperature anomalies were recorded in the equatorial Pacific. central. These anomalous temperature rises gradually spread to the entire equatorial basin. The most salient moment of the phenomenon occurred in December 2006, although the anomalies did not exceed 1.5В ° C in the eastern basin. Later there was an episode of La NiГ ± a in the equatorial Pacific. The temperature indices of the El NiГ ± o region are below -1.5В ° C. The phenomenon stopped in spring 2007.

Open East Pacific Chlorophyll Maps for January, April and December 2006 and 2007. Describe the variations in quantity and distribution by comparing each pair of images.

2. What do you think is happening in the Western Pacific and Asia?


Organisms that have the same role in the food chain belong to the same level of nutrition. At the first level there will be the primary producers, at the second the herbivores (or primary consumers).

The trophic of nutrients, or the intake of the biomass of organisms by other organisms, involves a dispersion of energy: for each step of the chain, about 80-90% of the potential energy is dissipated in the form of heat and consequently long foods (consisting of numerous trophic levels) must have at the base a copious primary production. The same factor implies an ever smaller population of a given species, the higher the trophic level to which it belongs. The passage of energy can also take place between organisms belonging to the same trophic level.

The flow of energy through a trophic level is equal to the total assimilation (A) at that level, which in turn is equal to the production (P) of biomass and organic matter plus respiration (R): A = P + R

Food chains are divided into:

  1. grazing food chains: vegetables → herbivores (or primary consumers) → carnivores (or secondary consumers)
  2. food chains of detritus: dead organic matter → microorganisms and other consumers of detritus (detritivores) → their predators

The quality of the resources is at least as important as the quantity of energy directed into the different food chains (eg the quality of a photosynthetic extract obtained from a mycorrhizal fungus is much higher than that of dead leaves in terms of ease of assimilation). All food chains have a feed-back in which consumers often carry nutrients or hormonal products that can affect the plant's resources. It is a sequence that always starts with the producers.

At the base of every food chain there are producers, i.e. autotrophic organisms, that is, capable of organizing chemical compounds in the soil (or water), so as to autonomously produce food reserves (sugars, starches). This process is feasible through the energy provided by chlorophyll photosynthesis. Producers are in fact the only living beings who are able to transform solar energy (light energy + thermal energy) into chemical energy (binding energy).

After the producers, there are the consumers, that is, heterotrophic organisms that are not independent in the production of food. In fact, these organisms need to eat other organisms to assimilate nutrients. In the context of consumers, there are several trophic levels, generally 3:

  • primary consumers: herbivores that feed directly from producers, such as rabbit, deer, pigeon, gazelle, grasshopper, buffalo, zebra, giraffe and elephant
  • secondary consumers: carnivores that eat herbivores, such as fox, cat, hawk, dolphin, weasel, tuna, octopus, spider and lizard
  • tertiary consumers: carnivores that eat both herbivores and other carnivores, for example the lion, the tiger, the leopard, the wolf, the killer whale, the crocodile, the python, the shark and the eagle. The latter are commonly referred to as super predators or alpha predators.

Each of these orders represents a trophic level.

Consumer orders, however, are virtually unlimited. The dispersion of energy at each passage, however, means that the population of species belonging to high trophic levels is always and in any case limited (eagles, placed at the sixth trophic level of an Alpine trophic chain, have a very large hunting territory precisely because of this reason).

A species can occupy multiple trophic levels, depending on the food energy source it feeds on. Omnivores, like bears, do not occupy a fixed level, but vary it according to what they eat.

Bioreducers are generally bacteria that decompose animal and plant remains into substances that can be reused by manufacturers. They play a very important role because by determining the decomposition of organic matter, they remineralize the nutrients (especially nitrogen and phosphorus) which are reused by autotrophic organisms. They transform organic molecules into inorganic molecules.

A trophic cascade is an ecological process that starts at the beginning of the food chain and tumbles down to the end. The classic example is what happened in Yellowstone National Park in the United States when wolves were reintroduced in 1995.

The food chain

The nature of the human being and the food chain.

Often, speaking with friends or omnivorous acquaintances, I hear it said that humans, like all animals, follow the "food chain".
In reality this statement is either an excuse, or it is ignorance, or it is said in bad faith perhaps to justify the consumption of meat and the consequent killing of animals destined to become food for us humans. Food of which man, not being part of the food chain, can very well do without finding in all the food of vegetable origin what he needs to live healthy and also eat with taste.
The human being does NOT follow a "food chain" but a "food web", which is quite different (which has been built over time by being born a frugivore, collector, fruitarian and herbivore, but not carnivorous).

There would be a lot to write about the human features that demonstrate the veracity of this type statement: length of the intestine, shape of hands and fingers, movements - lateral and vertical - of the jaw - the carnivore moves the jaw only vertically, way of chewing and dentition that are features of more herbivorous than carnivorous beings.
The lion, like the wolf, the tiger and any carnivorous predator, can only feed on meat so its food chain is meat. Usually it involves hunting old or sick prey that could infect the pack. Therefore, the carnivorous food chain, in addition to feeding predators, also plays an important role in maintaining the healthy species to allow its natural continuation and not risk its existence due to various epidemics.
The "food web" (or food web) is the network of flows of matter and energy between the components of an eco-system. It means "who eats what" within that eco-system.
"Food chain", in ethnology, is the complex of organisms (animals, plants, bacteria) of an eco-system that depend on each other for mutual but also altruistic interest.
Individuals can also be part of different eco-systems, giving rise to a "food web" ... that of man which, however, unlike the "food chain" is only useful to himself.
I find it really scary how humans see in that "food chain" a form of their food and not the murder (pass me the term) of a defenseless and sentient being who does not want to die but live his life carrying out all his functions for which he was born (procreate to ensure the continuation of the species, raise his cubs, care for them lovingly, cuddle them, play with them and, through play, teach how to survive in Nature (all things not different from what human parents do) and which, instead, is raised, imprisoned, exploited, abused, distorted and fed (not even with its natural food) only to be eaten by us humans.

food chain

In every environment, a living being finds its habitat, that is, the living conditions it needs and every organism must eat. However, in turn, it can be eaten by those who could not live without hunting and eating its natural food.
All animals and plants are linked in a chain that has these rules: eat and be eaten.
Vegetables are the first link in the food chain, because they are the producers if a snail eats a leaf, here is a food chain made up of two links, a producer and a primary consumer.

  • Two rings:
    if a bird feeds on the snail, the chain lengthens, because there is a secondary consumer.
  • Three rings:
    in the environment there are many three-ring food chains, with a plant, a herbivore and a carnivore, but if a hawk eats the smallest bird, there is another link, because there is a tertiary consumer.
  • Four rings:
    at the end of its life, the hawk will die and fall to the ground, where it will be eaten by decomposers, which are bacteria and molds.
    These release the substances needed by the plants back into the soil and the chain closes.

Only the human being limits himself to eating without giving back anything (or very little ... food for some worm, as long as his body is not cremated) and does not return in a fair way in Nature what he has torn from animal Nature.
But you know ...
The human being, in this respect (and not only), is extremely selfish. One of the many not beautiful features that make it different (in negative) from animals.
Carnivorous human? Man cannot be born a carnivore for various reasons, in addition to his physical conformation (as already written above) but, above all, because, although physically strong, at the time he could not hunt as predatory wild animals did, relying only on the exhaustion of the prey that, chased for days, eventually succumbed.
Furthermore, man had not yet discovered neither fire nor the technique to forge weapons suitable for hunting.
Here is one of the many proofs that man was not born a carnivore but was:

  • frugivorous: it fed on fruits and seeds
  • phytophagous: it fed on roots it collected
  • herbivore: plant-based
  • mammal equipped with teeth suitable for chewing plant foods and not for tearing strips of skin and hard meat from a hypothetical prey.

Man can eat meat only if it is "matured": that is, only after the "rigor-mortis" process has passed, otherwise, due to its teeth, shape and jaw strength, eating fresh meat would be an impossible task.
Then, over time, it has become omnivorous but, above all, carnivorous with all the health consequences (various diseases, including tumors) deriving from the disseminated consumption of meat.
An organism that receives a "food" that is not suitable for its proper functioning (just think of what becomes a piece of meat or derivative that is eaten by a human begins to be digested, in part, already in the mouth continues in the stomach, passing for meters and meters of intestine (about 8 times the length of the person's trunk), at a temperature of 37 degrees, transforming into a "putriscina or cadaverine", a highly inflammatory putrid mass and fertile ground for the proliferation of any type of tumor, primarily the tumor to the colon, much increasing exponentially with the consumption of meat.
How can we not understand that the human body, so nourished, is destined to get sick?
But even today, the human being, in all his intelligence and wisdom, does not seem to have understood it, if not to a minimum, unfortunately.
Agnese Albertini

Video: Science Videos - Food Chain - Kids Second Grade

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