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Matthew Coleman, Jessica Smith, Jennifer Stewart, Brian Torres
Monitoring Ecosystem Health Using Biomagnification in Ospreys
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?
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 possiblythe cause of thousands of two headed fish that spawned in theNoosa 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
Picture from: http://www.unbc.ca/nlui/wildlife_diseases_bc/lead_hatchet_breast.jpg
A common side effect of lead poisoningis the lack of fat and atrophy of breastmuscles in birds.
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
Biomagnification
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.
Ospreys
Aquatic Vertebrates
Aquatic Invertebrates
Polyhalogenated aromatic hydrocarbons
Heavy Metals (Mercury, Lead)
Bio
mag
nific
atio
n
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 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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