Biomagnification and the Trouble with Toxins

Summary

Highlights

• Biomagnification causes toxins to concentrate as they ascend the food chain. 🐛➡️🦅
• DDT use led to a decline in bald eagle populations due to thinning egg shells. 🦅
• Mercury is another example of a toxin that can biomagnify. 🌿🐟
• Biomagnification emphasizes the need for responsible environmental management. 🌱
• The video encourages innovative solutions, such as using viruses to specifically target pest insects. 🦠

Key Takeaways

• Biomagnification is when toxins become more concentrated at higher levels of the food chain. 🐟➡️🦅
• DDT is an infamous example that affected species such as the bald eagle. 🦅
• Even tiny insects can be crucial in the biomagnification process; their toxins move up the food chain. 🐜
• Alternative pest control methods and ecological awareness are critical in addressing these issues. 🌍
• Uncontrolled toxins can enter air, soil, and water, impacting environments globally. 🌎

Overview

Chapters

• 00:00 - 00:30: Introduction to DDT in Song Lyrics The chapter introduces the concept of DDT through its mention in song lyrics, specifically the song 'Big Yellow Taxi' by Joni Mitchell. The narrator mentions how the song asks farmers to put away their DDT, reflecting on how song lyrics can convey important messages.
• 00:30 - 01:00: Understanding DDT The chapter titled 'Understanding DDT' explores the history and impact of DDT, a chemical pesticide. Initially, a reference to DDT in a song lyric is mentioned, which might have gone unnoticed by younger audiences but becomes more impactful with age. The chapter clarifies that DDT is an abbreviation for its chemical name, which isn't elaborated in detail. The use of DDT became quite popular in the 1940s due to its effectiveness as a pesticide.
• 01:00 - 01:30: DDT Usage and Environmental Impact This chapter discusses the usage of DDT, highlighting its popularity in agriculture due to its effectiveness in killing insect pests that destroy crops. However, it soon faced scrutiny as its negative environmental effects became evident. In response, the Environmental Protection Agency (EPA) issued a cancellation order for DDT in 1972. The EPA continues to collaborate with other countries to regulate DDT and similar chemicals.
• 01:30 - 02:00: DDT in Global Context The chapter titled "DDT in Global Context" explores the usage of DDT in different parts of the world, specifically in areas combating malaria through mosquito control methods, such as indoor residual spraying. It highlights that although DDT use is much more regulated today, the historical and environmental impacts of its application were significant. A key lesson learned from DDT's use is its unintended consequences, where higher-level consumers in the food chain, like bald eagles, suffered detrimental effects.
• 02:00 - 02:30: Introduction to Biomagnification The introduction to biomagnification discusses how the phenomenon affected bald eagles, particularly their reproductive abilities, leading to the thinning of their eggshells. Although bald eagles do not eat the small insects targeted by DDT, the chemical's effects are felt across species due to biomagnification. The chapter suggests that this process does not only apply to DDT, but to many other chemicals and toxins.
• 02:30 - 03:00: Example of Biomagnification with Mercury This chapter discusses the concept of biomagnification using mercury as an example. Biomagnification refers to the process whereby toxins become increasingly concentrated in the tissues of organisms higher up the food chain. This concentration occurs as larger organisms consume smaller ones that have absorbed toxins, such as mercury. The chapter starts by illustrating the concept with the example of poisoned insects, as the toxins from these insects increase in concentration in their predators up the food chain.
• 03:00 - 03:30: Biomagnification Process Explained The chapter explains the concept of biomagnification, starting with the impact of toxins on insects. It highlights how some insects become easy prey for predators after being weakened by the poison. Although many insects die, not all of them are eliminated, and each surviving insect carries a dose of the toxin. These insects are then consumed by secondary consumers such as lizards or rodents. As a result, the toxins become more concentrated in the bodies of these secondary consumers, illustrating the process of biomagnification.
• 04:00 - 04:30: Consequences of Toxin Mismanagement In this chapter, the concept of the energy pyramid and trophic levels is discussed, highlighting how only 10% of energy is transferred from one trophic level to the next, while the rest is lost as heat or remains undigested. Due to this inefficiency, organisms at higher trophic levels need to consume more biomass from the lower levels to survive. This chapter also raises concerns about the accumulation of toxins, which are stored in the tissues of organisms and passed along the food chain, posing risks as organisms higher in the trophic levels consume those below.
• 04:30 - 05:00: Implications on the Environment This chapter discusses the implications of toxin accumulation in the environment. It highlights how toxins can magnify as they move up the food chain, particularly affecting tertiary consumers like predatory birds. These birds need to consume large amounts of secondary consumer biomass to survive but in doing so, accumulate higher concentrations of toxins. This is due to the inefficiency of energy transfer through trophic levels, where only 10% of energy is passed to the next level. The text warns about the dangers of uncontrolled chemical and toxin presence in the environment.
• 05:00 - 05:30: Call to Action for Solutions The chapter discusses the process of biomagnification, particularly focusing on the pesticide DDT. DDT spreads into the environment, including air, soil, and water. Once in the water supply, it is ingested by primary consumers like small fish, leading to a build-up of the chemical in their tissues. As these small fish are eaten by secondary consumers, such as larger fish, the concentration of DDT increases higher up the food chain. This magnified effect raises concerns about the impact on the ecosystem and highlights the need for solutions to address such environmental issues.
• 05:30 - 06:00: Closing Remarks In the closing chapter, the focus is on biomagnification and its impact on tertiary consumers, like bald eagles, due to increased concentrations of toxins and pesticides in their tissues. The takeaway is the importance of considering biomagnification when manufacturing any chemical toxins or pesticides. The chapter concludes with a call to action for innovative solutions to these ecological challenges. Additionally, it invites readers to explore the end of a virus-themed video that demonstrates a virus used as a targeted pesticide against specific pest insects.

Biomagnification and the Trouble with Toxins Transcription

• 00:00 - 00:30 Captions are on! To turn off, click CC button at bottom right. Follow us on Twitter (@AmoebaSisters) and Facebook! Have you ever heard the song “Big Yellow Taxi?” It’s one of our favorites. It was originally written and recorded by Joni Mitchell back in the seventies, and there are lots of singers who have their own recordings of her song. Great song. The song has this verse in it that asks “farmers to put away their DDT.” You know when you’re young and you don’t understand a lyric in a song---you kind of---make
• 00:30 - 01:00 up what that might mean in your head? ….Ok maybe that’s just us. We didn’t really get that lyric until we got older--- now we do---and it’s so much more powerful now. So of course, it deals with science. DDT is a chemical pesticide, and it is called DDT because it stands for this. Yeah…so we’re going to call it DDT. Its use really sparked in the 1940’s as a powerful chemical pesticide---meaning it
• 01:00 - 01:30 was used to kill insect pests. Often the types of insect pests that destroy crops so it was popular in agriculture. DDT was very popular. But DDT soon came under some scrutiny. It became evident that pesticide was having negative environmental effects. In 1972, the EPA issued a cancellation order of DDT and the EPA still works with other countries to control substances such as DDT and similar chemicals.
• 01:30 - 02:00 DDT is used in other parts of the world, such as areas that are battling malaria and therefore looking for mosquito control options with indoor residual spraying. It is definitely far more regulated and controlled in its use today. One thing that DDT really taught us is that the effects went far beyond the little insects that it may be targeting. Some high level consumers, such as bald eagles for example, really took a bad hit from DDT.
• 02:00 - 02:30 For bald eagles, this affected reproductive abilities, including severe thinning of bald eagle egg shells. But why? After all, bald eagles do not typically eat the small insects that the DDT targeted. This takes us into our topic of biomagnification. And biomagnification doesn’t just involve DDT. There are many chemicals and toxins that can be biomagnified.
• 02:30 - 03:00 Mercury is another example that you may hear about. When you think of anything being magnified, you think of it getting bigger. Biomagnification describes what happens when toxins become more and more concentrated in the living tissues of organisms as you go up in the food chain. But why does this happen? Take a look at these little bugs here. Imagine that perhaps these insects have been poisoned. Here are some still living poisoned insects.
• 03:00 - 03:30 Weakened, some may make easy targets for predators. This poison is killing off a lot of the insects but not all of them. Each of these insects will contain one triangle, which represents a concentration of that toxin. Now imagine these insects are eaten by secondary consumers such as lizards or rodents. As those secondary consumers eat those insects, the toxin concentration level increases in the secondary consumers.
• 03:30 - 04:00 Why? Well recall in the energy pyramid, that organisms only keeps 10% of the energy from the trophic level below. The remaining is lost as heat or undigested. That means that as you move up trophic levels, the animals will have to consume far more biomass from the level below to be able to compensate for this and survive. And everything it consumes from that trophic level below could have that toxin stored in its tissues---which now, is an unwanted gift.
• 04:00 - 04:30 It’s adding up. Now if a predatory bird begins to eat these secondary consumers, this concentration further increases. Remember it only gets 10% of the energy from the trophic level below----and so as a tertiary consumer----it must eat a significant amount of secondary consumer biomass to survive. Increasing toxin concentration in the tissues! The problem with many toxins or chemicals is that if they are not controlled well, they
• 04:30 - 05:00 can get into the air, the soil, the water. With DDT, it was able to get into the water supply. Primary consumers, such as small fish, began to feed on those producers. The concentration in body tissues of the poison in the primary consumers increased due to biomagnification. Secondary consumers, such as larger fish, feed on those primary consumers. The concentration in body tissues of the poison in the secondary consumers increased due to
• 05:00 - 05:30 biomagnification. Tertiary consumers, such as bald eagles, feed on the secondary consumers. The concentration in body tissues of the poison in tertiary consumers increased due to biomagnification. In summary, biomagniciation is a major factor to consider for any pesticide or chemical toxin that humans may make. We need people like you to come up with new solutions! If you take a look at the end of our virus video, you can learn about a virus that has been used as a pesticide as it only attacks specific types of pest insects.
• 05:30 - 06:00 What if viruses were manipulated to attack specific pests to avoid the use of toxin? But even then, could there be consequences for taking out specific types of pest insects? One last thing to mention. Animals face additional problems such as habitat destruction, habitat loss, and poaching. There are ecologists who devote their lives to helping these organisms and raising awareness
• 06:00 - 06:30 among people like you. Truly, a career for the brave and bold. That’s it for the amoeba sisters and we remind you to stay curious!