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 References “Assessing metal bioaccumulation in aquatic environments: The inverse relationship between bioaccumulation factors, trophic transfer factors and exposure concentration.” Aquatic Toxicology. 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