A POWERPOINT PRESENTATION ON BIO MAGNIFICATION AND TEN PERCENT LAW.

1. BY
DIVYA RAJPUT

2. BIOMAGNIFICATION
EXAMPLE
CAUSES OF BIOMAGNIFICATION
PROCESS OF BIOMAGNIFICATION
EXAMPLE
BIOCONCENTRATION
PROCESS OF BIOCONCENTRATION
BIOACCUMULATION
SUBSTANCES THAT BIOMAGNIFY
TEN PER CENT LAW
FOOD CHAIN
EXAMPLE

3. The increase in the concentration
of harmful chemical substances
like pesticides in the body of the
living organisms at each tropic
level of a food chain is called bio
magnification.
Biomagnification, also known
as bioamplification or biological
magnification, occurs when
the concentration of a substance,
such as DDT or mercury, in an
organism exceeds the
background concentration of the
substance in its diet.

4. Biological magnification often refers to
the process whereby certain substances
such as pesticides or heavy metals move
up the food chain, work their way into
rivers or lakes, and are eaten by
aquatic organisms such as fish, which
in turn are eaten by large birds,
animals or humans. The substances
become concentrated in tissues or
internal organs as they move up the
chain. Bioaccumulants are substances
that increase in concentration in living
organisms as they take in contaminated
air, water, or food because the
substances are very slowly metabolized
or excreted.
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5. EXAMPLE
The following is an example showing how bio-
magnificationtakes place in nature: An
anchovy eatszoo-planktonthat have tiny
amounts of mercurythat the zoo-plankton
has pickedup fromthe water throughoutthe
anchovies lifespan. A tuna eats many of these
anchovies over its life, accumulating the
mercury in eachof those anchovies into its
body. If the mercurystunts the growthof the
anchovies, that tuna is required to eat more
little fish to stay alive. Becausethere are more
little fish being eaten, the mercury content is
magnified.
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6. CAUSES OF BIOMAGNIFICATION
¶ Persistence – where the substance can't
be broken down by environmental
processes
¶ Food chain energetics – where the
substance concentration increases
progressively as it moves up a food chain
¶ Low or non-existent
rate of internal
degradation or
excretion of the
substance – often due
to water-insolubility
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7. PROCESS OF BIOMAGNIFICATION
‡ Bioaccumulation occurs within a tro
phic level, and is the increase in
concentration of a substance in
certain tissues of organisms' bodies
due to absorption from food and the
environment.
‡ Bioconcentration is defined as
occurring when uptake from the water
is greater than excretion.
Thus, bioconcentration and bioaccumulation occur within an organism, and
biomagnification occurs across trophic (food chain) levels.
Although sometimes used interchangeably with "bioaccumulation", an important
distinction is drawn between the two, and with bioconcentration.

8. Biodilution is also a process that occurs to all trophic levels in
an aquatic environment; it is the opposite of biomagnification,
thus a pollutant gets smaller in concentration as it progresses
up a food web.
Lipid, (lipophilic) or fat soluble substances cannot be diluted,
broken down, or excreted in urine, a water-based medium, and
so accumulate in fatty tissues of an organism if the organism
lacks enzymes to degrade them. When eaten by another
organism, fats are absorbed in the gut, carrying the
substance, which then accumulates in the fats of the
predator. Since at each level of the food chain there is a lot
of energy loss, a predator must consume many prey, including
all of their lipophilic substances.
DDT is thought to biomagnify and biomagnification is one of
the most significant reasons it was deemed harmful to the
environment by the EPA and other organizations. DDT is
stored in the fat of animals and takes many years to break
down, and as the fat is consumed by predators, the amountsINDEX

9. EXAMPLE For example, though mercury is only
present in small amounts in seawater, it
is absorbed by algae (generally as
methyl mercury). It is efficiently
absorbed, but only very slowly excreted
by organisms. Bioaccumulation and
bioconcentration result in build up in
the adipose tissue of successive trophic
levels : zooplankton, small nekton,
larger fish, etc. Anything which eats
these fish also consumes the higher level
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of mercury the fish have accumulated. This process explains why
predatory fish such as swordfish and sharks or birds like osprey
and eagles have higher concentrations of mercury in their tissue
than could be accounted for by direct exposure alone. For example,
herring contains mercury at approximately 0.01 parts per million
(ppm) and shark contains mercury at greater than 1 ppm.

10. BIOCONCENTRATION
Accumulation of harmful chemicals such as
pesticides in the living organisms like plants,
animals and humans unknowingly, through the
food chain, is called Bioconcentration. It is the
accumulation of a chemical in or on an organism
when the source of chemical is solely water.
Bioconcentration is a term that was created for
use in the field of aquatic toxicology.
Bioconcentration can also be defined as the
process by which a chemical concentration in an
aquatic organism exceeds that in water as a result
of exposure to a waterborne chemical.
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11. PROCESS OF BIOCONCENTRATION
¡ Pesticides are poisonous chemical
substances which are sprayed over
crop plants to protect them from
pests (harmful small animals) and
diseases.
¡ These chemicals pesticides mix up
with soil and water.
¡ From soil and water, these pesticides
are absorbed by the growing plants
alongwith water and minerals.

12. ¡ When herbivorous animals eat plant food,
then these poisonous chemical pesticides go
into their bodies through the food chain.
¡ And when the carnivorous animals eat
herbivores, then the pesticides get
transferred to their bodies.
¡ Man being an omnivore, eats plant food as
well as herbivores.
¡ So, the pesticides present in plant food
and herbivores also get transferred to
the man’s body through food.

13. ¡ Thus, pesticides enter the food chain at the producer
level (plant level).
¡ And in the process of transfer of food through food chains
these harmful chemicals get concentrated at each tropic
level.
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14. BIOACCUMULATION
§ An increase in the
concentration of a
pollutant in a biological
organism compared to
its concentration in
the environment.
§ Collecting of substances
in an organism or part
of it.
§ It is how pollutants
enter a food chain.
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15. SUBSTANCES THAT BIOMAGNIFY
There are two maingroups of substances that biomagnify.
Bothare lipophilic andnot easilydegraded. Novelorganic
substances are not easilydegradedbecause organismslack
previous exposure and have thusnot evolved specific
detoxificationand excretion mechanisms, as there has been
no selection pressure from them. These substancesare
consequentlyknown as "persistent organic pollutants" or
POPs. Metalsare not degradable because theyare elements.
Organisms, particularlythose subject to naturallyhigh
levels of exposure to metals, have mechanisms to sequester
and excretemetals. Problems arise whenorganismsare
exposedto higher concentrationsthan usual, whichthey
cannot excreterapidlyenoughto prevent damage. Some
persistent heavymetals are especiallyharmfulto the
organism's reproductive system.
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16. The Ten percent law for the transfer
of energy from one trophic levelto the
next was introduced by Raymond
Lindeman(1942). According to this law,
during the transfer of energy from
organic food from one trophic level to the
next, only about ten percent of the
energy from organic matter is stored as
flesh. The remaining is lost during
transfer, broken down in respiration, or
lost to incompletedigestion by higher
trophic levels.

17. During the transfer of energy through successive tropic
levels in an ecosystem, there is a loss of energy all
along the path. No transfer of energy is 100 per cent.
The studies of transfer of energy in different food
chains in a large number of ecosystems has revealed a
uniform pattern of transfer of energy, which is given
by 10 per cent law. The 10 per cent law is one of the
most useful generalisations about the magnitude of loss
of energy in food chains. According to ten per cent
law, only 10% of energy entering a particular tropic
level of organisms is available for transfer to the next
higher tropic level. All the energy transfers in a food
chains follow the 10% law which in simple terms means
that the energy available at each successive tropic
level is 10% of the previous level. Thus, there is a
progressive decline (gradual reduction) in the amount of
energy available as we go from producer level to theINDEX

18. FOOD CHAIN
Plants absorb 1 percent sun
energy for primary production
and can store only 10% of the
utilized energy as net
production available for
the herbivores. When the
plants are consumed by animal,
about 10% of the energy in the
food is fixed into animal flesh
which is available for next
trophic level (carnivores or
omnivores). When a carnivore
or an omnivore consumes that
animal, only about 10% of
energy is fixed in its flesh for
the higher level.
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19. EXAMPLE
Suppose 1000 joules of light energy emitted by the sun falls on the plants.
Plants convert only 1% of the light energy falling on them into chemical
energy of food. So energy which will be available in plant matter as food
will be only 1% of 1000 joules, which comes to 10 joules. The remaining 1000
– 10 = 990 joules of light energy or solar energy which is not utilized by
plants is reflected back into the enviroment. The 10% law will not apply at
this stage. It will apply only in the transfer of energy in food chain.

20. Now, let us apply 10% law to the food chain:
Plants -> Herbivores -> Carnivores.
The plants or first tropic level has 10 joules of energy in it. Now,
according to 10% of joules of energy (which is 1 joule) will be available
for transfer at the next tropic level, so that the herbivore (deer) will have
only 1 joule of energy stored as food at the secod tropic level. Applying
the ten percent law again we find that 10% of the remaining 1 joule
(which is 0.1 joule) will be transferred to third tropic level of carnivore
(lion). So, the energy available in the lion as food will be only 0. 1 joule.
We will now solve some problems based on ten per cent law.
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