Carbon and Nitrogen Cycles

Summary

In this video by the Amoeba Sisters, the focus is on the fascinating cycles of carbon and nitrogen, essential for life on Earth. They use a rotating compost bin as an engaging entry point to discuss how these elements cycle through different forms and reservoirs in nature. Carbon, despite its versatile and indispensable nature, and nitrogen, crucial for proteins and nucleic acids, both play critical roles in sustaining life. The video explains how these elements move through natural systems via processes like photosynthesis, respiration, decomposition, and nitrification. The video also highlights the environmental implications of these cycles including climate concerns and nitrogen pollution.

Highlights

• Rotating compost bins are a fun tool for composting, helping with aeration! 🌱
• Carbon is everywhere! It's in graphite, diamonds, and all major biomolecules. 💎
• The carbon cycle involves reservoirs like oceans, rocks, and living organisms. 🌊
• Photosynthesis and respiration are key processes in the carbon cycle. 🍃
• Nitrogen, vital for proteins and nucleic acids, is abundant in the atmosphere. 🌬️
• Nitrogen must be fixed into usable forms by bacteria, a crucial part of its cycle. 🦠
• Excess nitrogen from fertilizers can harm aquatic environments by depleting oxygen. 🐠
• Balancing carbon and nitrogen cycles is critical for environmental health. ⚖️

Key Takeaways

• Carbon and nitrogen cycles are crucial for life and maintain ecological balance. 🌍
• Carbon's versatility makes it a 'building block of life,' found in countless forms. 🔄
• Nitrogen needs to be converted by bacteria into usable forms for organisms. 🤝
• Compost is a practical way to participate in the carbon and nitrogen cycles. 🌿
• Managing nitrogen levels in agriculture is important to prevent ecological issues. 🚜

Overview

The Amoeba Sisters introduce us to the intricate magic of carbon and nitrogen cycles, using a nifty rotating compost bin as a gateway. These bins help introduce air into compost, speeding up the decomposition process to create nutrient-rich material. This serves as a perfect analogy for how essential carbon and nitrogen are to plant growth, with compost providing these vital nutrients directly to plants.

Carbon, the incredible element they favor over all others, appears in a multitude of forms from graphite to diamonds, and is a key component of all major biological molecules. The sisters explain how carbon cycles through different reservoirs, such as the atmosphere, organisms, and fossil fuels, emphasizing processes like photosynthesis and respiration that move and transform carbon within ecosystems. This highlights carbon's role as a foundational element in life and the need to understand its environmental impacts, especially regarding greenhouse gases.

Shifting focus to nitrogen, the video covers its critical role in forming proteins and nucleic acids. As the most abundant atmospheric gas, nitrogen must first be fixed into compounds like ammonium and nitrates to be usable by plants, a process mediated by bacteria. The Amoeba Sisters illustrate how agricultural practices can influence these cycles, stressing the importance of balancing nitrogen levels to avoid pollution and ecological damage in aquatic systems. They conclude by celebrating these cycles as beautiful natural processes connecting all living things.

Chapters

• 00:00 - 00:30: Introduction and Compost The chapter discusses the speaker's excitement about a new purchase - a rotating compost bin. The importance of composting is briefly touched upon, highlighting the concept of aeration through the rotation of the compost bin, which aids in the decomposition of biodegradable materials. The speaker shares a personal anecdote to make the topic relatable and engaging for the audience.
• 00:30 - 02:00: Importance of Carbon This section discusses the importance of carbon in composting and plant nutrition. It describes how various organic materials such as leaves, banana peels, grass clippings, twigs, and overripe fruits break down into nutrient-rich compost. This compost provides essential nutrients, particularly carbon, which is vital for plant growth and health.
• 02:00 - 03:30: Carbon Cycle Overview The chapter discusses the importance of carbon and nitrogen in life due to their cycles. Despite the numerous significant elements on the periodic table, carbon is highlighted as a favorite due to its versatility. The text uses the example of graphite in pencils to illustrate carbon's diverse nature.
• 03:30 - 06:00: Carbon Cycle Details The chapter delves into the vital role of carbon in various forms and substances, detailing how it comprises essential biomolecules like carbohydrates, lipids, proteins, and nucleic acids. The importance of organic molecules, specifically those containing carbon, is emphasized, along with a nod to organic chemistry as the scientific study of these interactions.
• 06:00 - 07:30: Introduction to Nitrogen The chapter introduces the importance of carbon, emphasizing its role in forming numerous compounds due to its four valence electrons. Carbon is described as a fundamental building block of life. The chapter promises to elaborate on how carbon is obtained by looking at its cycle and acknowledging carbon reservoirs. This sets the stage for an exploration into the carbon cycle.
• 07:30 - 09:30: Nitrogen Cycle Details The chapter discusses the carbon cycle, which is the exchange of carbon among various reservoirs. These reservoirs include the ocean, rocks and fossil fuels, living organisms, and the atmosphere. The summary emphasizes understanding how carbon cycles among these reservoirs and introduces the concept of carbon dioxide in the atmosphere as a point of focus.
• 09:30 - 11:30: Importance of Balance in Cycles The chapter 'Importance of Balance in Cycles' discusses the carbon cycle, emphasizing the role of photosynthesis in carbon absorption. Photosynthetic organisms like plants and algae absorb carbon. When animals eat these organisms, the carbon becomes part of their body. Cellular respiration by both plants and animals releases carbon dioxide, but when these organisms die, the carbon can be stored in sediment.

Carbon and Nitrogen Cycles Transcription

• 00:00 - 00:30 Captions are on! Turn off by clicking CC button at bottom right. Follow us on Twitter (@AmoebaSisters) and Facebook! So last weekend, my family bought something pretty cool. Something we’re sure you’ve always wanted. No, it’s not a pony. It’s a rotating compost bin! Yeah! It’s for compost and it rotates. Which is going to be so awesome because the rotating part, that allows it to get aeration. You may already know about compost. It’s where biodegradable things can decompose and the whole idea is---after decomposing,
• 00:30 - 01:00 the result is this nutrient rich organic material that you can provide your plants with. So I’m thinking after a while of adding leaves, banana peels, grass clippings, twigs, overripe fruit…ok I could keep going but I won’t…after all these items break down and decompose, I’m hoping to get some nutrient rich material for my plants. So why am I even talking about this? Well there are two major things that compost supplies plants with that are so important---carbon
• 01:00 - 01:30 and nitrogen. We’re going to spend some type talking about these 2 elements---and their cycles---because both are so important for life. With so many incredible elements on the Periodic table, we don’t know if it’s really fair to have a favorite. But we do. It’s carbon. Sorry nitrogen, you’re cool too. But why the love for carbon? Well, we really love how versatile it is. In one form it could make up your pencil led---which isn’t really lead at all, it’s graphite.
• 01:30 - 02:00 It’s a form of carbon. In another form, carbon can make up one of the hardest substances, diamond. The big 4 biomolecules---carbohydrates, lipids, proteins, and nucleic acids—they all have carbon. In fact, molecules that contain carbon are known to be organic molecules. Organic chemistry is a branch of science that studies the interactions of molecules that contain carbon!
• 02:00 - 02:30 Just look at this carbon atom. Ahh, just look at it. It has 4 valence electrons. Carbon has the ability to form tons of compounds. Carbon is often known as a building block in life for this reason. Now that we understand how important carbon is, let’s make sure we understand how we get carbon. That means we need to take a look at how carbon can cycle. First it’s important to understand that there are carbon reservoirs and that the carbon
• 02:30 - 03:00 cycle is really an exchange of carbon among these reservoirs. Reservoirs being where carbon is basically hanging out. So here are some major examples of where carbon is found: Carbon is dissolved in the ocean. It is in rocks and fossil fuels. It is in living organisms. It can be in the atmosphere. So the idea is to understand that carbon cycles among these reservoirs. Now our time is limited…let’s take a look at one pathway. Consider carbon dioxide in the atmosphere.
• 03:00 - 03:30 It is taken in by organisms that perform photosynthesis. This may be plants, like land plants. It may be algae in oceans or lakes. The carbon becomes a part of that photosynthetic organism. If the photosynthetic organism is eaten by an animal, it becomes a part of that animal too. And the animals that eat that animal. Both the plants and animals do cellular respiration which releases carbon dioxide. When the plants and animals die, the carbon from their bodies can be stored in sediment
• 03:30 - 04:00 over a long period of time---after a very long time, they can even be converted into a fossil fuels. The burning of fossil fuels produces a lot of carbon dioxide---and this has also led to the concern of excessive carbon dioxide in the atmosphere. Carbon dioxide is a ‘greenhouse gas’ which means that it can trap heat in the atmosphere-------so too much carbon dioxide----is not a good thing. So what about nitrogen?
• 04:00 - 04:30 Nitrogen is a critical element in amino acids, which are the monomers of proteins----and an element of nucleotides, which are the monomers of nucleic acids. And if you remember from our biomolecule video, proteins and nucleic acids are two very important biomolecules for life. Nitrogen is kind of a big deal in the atmosphere considering it’s the primary gas in the atmosphere. The thing about nitrogen is that it is much more useful to organisms when fixed into other,
• 04:30 - 05:00 more usable forms. Nitrogen can be fixed by bacteria which could be living in the soil or even in the roots of some types of plants where the bacteria live in symbiotic harmony inside the roots---meaning the bacteria get a home in the plant root and the plants get the benefit of fixed nitrogen. Once again, we’re just looking at one pathway here in the nitrogen cycle so keep in mind this is just one way for nitrogen to cycle. Ok so let’s take a look at this nitrogen in the atmosphere.
• 05:00 - 05:30 Consider the types of plants that have nitrogen fixing bacteria living in their roots---the nitrogen is fixed by those bacteria into a form of nitrogen known as ammonia and ammonium. Nitrifying bacteria in the soil can convert the ammonium to nitrates and nitrites, forms of nitrogen that plants can also easily use and assimilate. Then animals can eat those plants and obtain nitrogen. When both plants and animals decompose, decomposers return ammonia to the soil in a process called
• 05:30 - 06:00 ammonification where it could be reused again. But not all of the nitrates and nitrites get assimilated by plants, eaten by animals, and then converted back into ammonia. There are also another type of bacteria in the soil…drumroll….denitrifying bacteria! Denitrifying bacteria in the soil can convert nitrates and nitrites back into atmospheric nitrogen gas. Again this is one example of nitrogen cycling through, but keep in mind that this happens
• 06:00 - 06:30 in both aquatic and terrestrial environments and there are other ways for nitrogen to be fixed and cycle. You know how we mentioned that too much carbon dioxide can be problematic? You want a balance in these cycles. There’s a balance for the nitrogen cycle too and nitrogen pollution can be problematic. Consider plant fertilizer. Plants love it. It contains a form of nitrogen. Well, if it’s not used responsibly, the excess nitrogen in fertilizing crops can drain
• 06:30 - 07:00 into bodies of water. One reason this could be harmful is that it will basically cause an aquatic producer heyday! All of the algae and water plants now have this crazy load of nitrogen for growth. That might sound like a good thing but all this producer excessive growth is messy---it can block light to the water and when they die and decompose, all that decomposing uses up a lot of dissolved oxygen in the water which can be harmful to aquatic life.
• 07:00 - 07:30 Phew! You know, this recycling of carbon and nitrogen is pretty remarkable. Just think---you could contain a carbon atom that was once part of…a dinosaur! Because of all this recycling. The carbon and nitrogen cycle---just another beautiful thing connecting all of us. Well I better get back to my compost. That’s it for the amoeba sisters and we remind you to stay curious!