Matthew Coleman, Jessica Smith, Jennifer Stewart, Brian Torres

Monitoring Ecosystem Health Using Biomagnification in Ospreys

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 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 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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