biomagnification

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Monitoring Ecosystem Health Using
Biomagnification in Ospreys
Matthew Coleman, Jessica Smith, Jennifer Stewart, Brian Torres
Introduction
Introduction

As human populations grow, so do the detrimental
effects of human activities
• Pollution
• Spread of industrial chemicals and pesticides
(Polyhalogenated aromatic hydrocarbons,
heavy metals)
•
•
These chemicals are present in low concentrations in
aquatic ecosystems
Monitoring the concentration of these chemicals in
ecosystems and detecting problems early is the most
efficient way to mitigate potential habitat contamination
and is crucial to conservation and environmental
planning
Introduction
 Knowing the impact of human pollution
 First step to mitigating existing pollution
problems
 Preventing the spread of new contaminants.
 Humans are also top predators and are
vulnerable to the effects of
biomagnification.
 Human exposure to polyhalogenated aromatic
hydrocarbons has been linked to obesity in
recent studies
Introduction
• The knowledge of two ecological concepts,
biomagnification and sentinel species concepts,
made us ask:
• What types of toxins are present in aquatic
ecosystems?
• What are the effects of these toxins on
organisms?
• How does biomagnification of toxins occur?
• What makes a good sentinel species?
• How can these concepts be applied to
effectively and noninvasively monitor the
toxin level within aquatic environments?
Results and Discussion
Toxins Often Present in Aquatic
Environments
 Novel Organic Compounds such as
Polyhalogenated aromatic
hydrocarbons (PAHs)
 Inorganic Compounds and Heavy
Metals
 What are the effects of these
contaminants on organisms?
Where do the contaminants
come from?
 Polyhalogenated aromatic hydrocarbons
(PAHs)
 DDE: the degraded form of DDT
 Other pesticides
 Flame retardants
 Burning chlorine-containing
compounds
 Bleaching paper
 Mercury
 Atmospheric deposition
 Mining and smelting
 Lead
 Mining and smelting
Negative effects of
PAHs
 Build up in lipids
 Bind to cell proteins
and DNA,
causing cell damage
and
possible mutations
 Growth of tumors
 Birth defects
In Australia, pesticides are possibly
the cause of thousands of two
headed fish that spawned in the
Noosa River earlier this year.
Negative effects of
heavy metals
 Mercury
 Decreased fertility
 Slowed organism
development
 Abnormal behavior
 Lead
 Kidney and liver
damage
 Brain, nervous
system, and
muscular damage
 Lower survival rate
of chicks
A common side effect of lead poisoning
is the lack of fat and atrophy of breast
muscles in birds.
Picture from: http://www.unbc.ca/nlui/wildlife_diseases_bc/lead_hatchet_breast.jpg
Sentinel Species and the
Biomagnification of Toxins
 What is biomagnification?
 The increase in concentration of a
substance that occurs with increasing
trophic levels as a consequence of food
chain energetics and low or nonexistent
ability to excrete or degrade a
substance.
 Also known as bioamplification or
biological magnification
Why does biomagnification occur?
 Energy is lost through successive trophic
levels, thus top predators much consume
more prey to sustain themselves
 The consumption of more prey introduces
the organism to an increased number of
lipophilic substances present in organisms
of lower trophic levels
Ospreys
Aquatic Vertebrates
Aquatic Invertebrates
Biomagnification
Biomagnification
Polyhalogenated aromatic hydrocarbons
Heavy Metals (Mercury, Lead)

Figure 1: Pollutants build up in aquatic ecosystems, and are
subsequently ingested by aquatic invertebrates and vertebrates,
which are then ingested by Ospreys, the top predators in the
ecosystem.
What Types of Toxins Biomagnify?
 Lipophilic substances cannot be
excreted through urine
 If an organism does not possess the
proper enzymes to break down a
substance, it will accumulate in the
organism’s body
Novel Organic Substances
• Not present in the evolutionary
environment of the organism
• Organism has not evolved methods of
detoxification or excretion
• Also called persistent organic pollutants
• Examples include DDT, PCBs, Toxaphene,
and Monomethylmercury
Inorganic Substances
• Metals cannot be degraded because they
are elements
• Many organisms have evolved
mechanisms to detoxify and excrete
metals because metals exist at low levels
in most environments
• However, pollution causes the
concentrations of metals to reach levels
much higher than most organisms have
• Examples include arsenic, cadmium,
mercury and lead
Sentinel Species Concept
 An organism that is used to
evaluate the levels of contaminants
in ecosystems, as well as the level
of environmental health
 Requirements of a sentinel species
 Top position in the food chain
 Long lifespan
 Adapts to contaminated
human landscapes
 Ability to accumulate
contaminants
 Wide population distribution
Why Ospreys as a Sentinel Species
for Aquatic Ecosystems?
1. Fish-eating atop the
aquatic food web
2. Long lived birds with
strong nest fidelity
3. Adapt to living near
humans
4. Tolerate short term
nest disturbance
5. Nests are evenly
distributed
6. Nests very visible and
easy to locate
7. Accumulate most
lipophilic
contaminants
8. Known sensitivity to
these contaminants
9. Worldwide distribution
Why Ospreys as a Sentinel Species
for Aquatic Ecosystems?



Osprey’s worldwide
distribution and tolerance
for living near humans
allows for monitoring near
humans and probable
causes of pollution
Nest visibility, fidelity and
tolerance of disturbance
means that samples can
easily be collected
Example: Ospreys were
used to successfully locate
the source of pollutants in
a river to a paper mill
upstream of the nesting
sites
Two common nesting
locations are trees and
telephone poles
Benefits of Using Osprey
 Ability to monitor which toxins are
reaching excessive levels
 Good for nearby terrestrial and
aquatic species to prevent further
contamination of aquatic ecosystems
by toxic substances
 Not necessary to kill Osprey, can use
feathers and egg shells
How are ecosystems
monitored?
 Eggshell samples
 Thinning of eggshells and reduced fecundity are
caused by toxins
 Indicates the presence of a toxin in the mother
before laying the egg
 Feather samples
 Indicates the presence of a toxin during the
young Osprey’s development
 Ospreys found with high levels of contaminants
 High likelihood that a water source in their home
range has become polluted
 Location can be pinpointed by analyzing water
flows and Osprey hunting behavior
Summary and Conclusions
Summary
 Pollution releases many toxic compounds into
aquatic ecosystems
 These compounds have negative effects on the
survival and health of organisms, especially top
predators, through the process of
biomagnification
 Sentinel species can be used to monitor the
presence of toxins and health of the ecosystem
 Osprey are an ideal species specifically for
monitoring aquatic ecosystems for various
reasons
 Osprey can be efficiently and noninvasively
monitored using feather and eggshell samples
Implications and Future Directions
 The implications of this research is
that it provides a new and easily
applied method to monitor ecosystem
health and presence of toxins
 Future research includes the search
for sentinel species for other types of
ecosystems such as deserts and
grasslands
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