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In this Nature League Lesson Plan, Brit explains some ocean basics and then answers questions related to the Earth’s seas.

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Welcome back to Nature League!

It's a brand new month, and that means it's time for a brand new theme. This month's theme is oceans, and while I'd love to spend a whole Lesson Plan on sharks, there are a ton of other topics within this theme that I'm excited to explore. [CHEERY INTRO MUSIC].

We film Nature League on location in Montana, and if you know U. S. geography, you know that the nearest ocean is a decent distance from here. That said, living a bit inland hasn't stopped me from loving the ocean.

The sea has always felt like home to me, and not just because it has sharks...the ocean simply captivates me and always has. So before this becomes a love letter from me to the sea, let's go through some ocean basics. One of the things that amazes me about the ocean is that it's... big.

Like... really big. Gigantic. The National Oceanic and Atmospheric Administration recently estimated the volume of the ocean to be approximately 1,335,000,000 cubic kilometers.

The ocean is so large that it's hard to even conceptualize this kind of size. Not only is the ocean massive, but it's also ancient. The planet Earth is estimated to be about 4 and a half billion years old.

What's crazy is that the Earth's oceans are almost as old as that. At its early stages, the Earth would have been two hot for liquid water, so one possibility as to how the oceans got here is that as the Earth cooled, water vapor condensed into liquid form. Another theory is that ice was delivered from space by comets or meteors, and then melted.

Either way, the water in the oceans is probably close to 4 /billion/ years old. Alright, so the ocean is really big, and really old. But what's happening inside?

How do humans interact with it? And who calls it home? There are so many ocean topics we could talk about that I had a hard time picking and choosing for this Lesson Plan.

So instead, I asked around to get an idea of what people would like to know about Earth's oceans, and for the rest of this Lesson Plan, we're going to mix it up a bit. It's time for an oceans Q and A!

Q: Is the fish population decreasing as dramatically as they say?

A: It's hard to talk about global trends for fish, partly because there are so many of them! Scientists estimate that there are over 15,000 species of marine fish. Of those, close to 200 are currently listed as either endangered or critically endangered by the IUCN Red List. Humans typically only affect a small percentage of those thousands of marine fish species; however, the ones we do affect, we tend to affect in major ways.

Q: What kind of niche ecology is in the deep sea?

A: A niche can be broadly defined as a species' functional role in an ecosystem. Basically, different species do different things, and the general patterns seen in the deep sea are similar to those elsewhere on Earth. However, there are some interesting exceptions. The deepest parts of the ocean don't receive any sunlight, so some niches are occupied a bit differently than we're used to.

On land and in shallow seas, the role of primary producer in an ecosystem is some kind of plant. However, without sunlight, the lowest levels of the food chain in the deep sea have to get their energy from somewhere else. Even though there's no sunlight, scientists estimate that there are over 17,000 marine species living in the deep sea.

It turns out that some of these creatures can create their own forms of energy from chemicals in the water, in a process called chemosynthesis. For example, chemosynthetic bacteria are the base of most deep ocean ecosystems, and they actually use sulfur from hydrothermal vents to form usable energy.

Q: What's the deal with giant squids?

A: What is the deal with giant squids? For one, they are real. Even though they've appeared in some famous works of /fiction/, giant squids are totally a non-fictional thing. The giant squid, or Architeuthis dux, is the largest invertebrate on Earth.

Amazingly, though, we know very little about them, and most of that knowledge has come from dead individuals that have floated up from the deep sea. So let's break down the “giant” thing. While they may not live up to the leviathan size depicted in mythology and fiction, giant squids are still pretty, well, giant.

They can grow up to 13 meters long, and catch prey using two feeding tentacles up to ten meters away! Also, they have the largest animal eyes on Earth- each one is about one foot in diameter!

Q: What are we doing about the pollution in our oceans?

A: At this point, plastics are the largest pollutant in the ocean when in comes to human-made products. Attention has been increasingly drawn to the issue, however, and just last year at the. United Nations Environmental Assembly, more than 200 nations approved a resolution to eliminate ocean plastic pollution. While this isn't legally binding, some countries have put legal restrictions in place.

Countries like Australia, Kenya, Chile, and the U. K. have either banned or imposed significant fines on plastic grocery bags.

Q: How do ocean currents affect the world?

A: How don't ocean currents affect the world?? Ocean currents work sort of like global conveyor belts, moving water, nutrients, and organisms all around. What's more, the ocean absorbs the majority of the sun's radiation, meaning that the oceans are almost like gigantic solar panels. When water heats up enough, it evaporates, meaning that ocean water actually affects the temperature, humidity, and weather patterns on land.

However, way more solar radiation hits the equators than the poles of the Earth. If there weren't any ocean currents, the heat and energy absorbed at the equator wouldn't get moved around to other places. This would result in the equator being way hotter, and the poles being /way/ colder.

So while ocean water affects local weather patterns, ocean currents actually affect global climate.

Q: How deep in the sea have humans gone?

A: To date, only three humans have gone to the deepest part of the Mariana Trench, which is the deepest known part of the ocean. That's insane to think about. Like...more people have been to the moon than to the deepest part of the ocean. In 2010, scientists measured the max depth of this trench to be approximately 10,994 meters or 36,070 feet deep.

As in...if you turned Mount Everest upside down, the top would still be a few kilometers away from the bottom. That is incredible.

Q: Have they found any fun new critters recently?

A: All the time! In 2018, marine research scientists discovered an entirely new ocean zone that we didn't know about. Within that zone the team found more than 100 new species previously unknown to science. What's insane is that this new ocean zone isn't super deep or's actually between 130 and 300 meters deep, and located in the Caribbean.

The team found new species like tanaids, which are super tiny crustaceans, dozens of new algae species, and even a black wire coral. If an entirely new biological community was just found in shallow-ish, commonly explored regions, just imagine what we don't know about the rest of the ocean.

Q: Are deep sea creatures basically aliens?

A: This is actually something I think about a lot. Whenever I watch science fiction movies with aliens, I can't help but think of Vampyroteuthis, or the vampire squid. If this isn't a science fiction alien, then I don't know what is. The deepest parts of the ocean- the parts inside of trenches in the bottom of the sea- are actually referred to as the “hadal zone”.

And here's a wild word for you- “hadal” actually comes from the name “Hades”, the Greek god of the underworld. Even the scientific words we have for the deep ocean have a mythological why not consider them aliens? If nothing- else, creatures from the deep ocean definitely deserve some royalties for sci fi costume design...

Q: Where are the sunken fortunes?

A: What, you think I got this for fun?

Q: Tell me more about bioluminescence?

A: Bioluminescence is when organisms emit light using a special biochemical reaction. While we do see examples of this on land- like fireflies- this phenomenon is most commonly seen in the oceans. Most people think of deep sea creatures when bioluminescence is mentioned. However, species throughout the Earth's oceans are capable of this feat.

You'll find bioluminescent species at the top of the water column, at the bottom of the ocean, right near the beach, or even in the middle of the ocean thousands of kilometers from land. And when you think about how big the deep ocean is, and how many species exist there, an interesting thought comes to mind- it's possible that bioluminescence is the most common form of communication on Earth.

Q: Can oceans can be harnessed to reverse climate change? What's an exact procedure?

A: “Exact procedure” is asking a bit much, but there are certainly some incredible ideas on the table at present. Geoengineering refers to large scale human intervention in Earth's systems to do things like combat climate change. Because the ocean is so integral to global climate and can capture greenhouse gases from the atmosphere, some of the most prominent geoengineering ideas involve the ocean. One of these is called ocean fertilization.

Here's how it works:. Phytoplankton take in the greenhouse gas carbon dioxide to do photosynthesis. When they die, the carbon dioxide is inside of them, and goes down to the bottom of the ocean instead of being in the atmosphere, contributing to global warming.

Ocean fertilization aims to boost the populations of phytoplankton, specifically by jacking up the ocean's iron content. Phytoplankton require iron to grow, so the idea is that doping the oceans with iron could boost their populations. While ideas like this are cool, the issue is that we don't fully understand the potential consequences.

In fact, large-scale ocean fertilization is actually banned by an international treaty at present, so it'll be some time before this actually happens, if at all. The ocean is crazy and beautiful and complex and most incredibly, is something we barely even know about. But there are some things we've figured out, and we'll be exploring these ocean components and themes throughout the month.

So, make sure to come back next week for an ocean themed Field Trip where we'll take it to the streets! Thanks to my friends for these ocean questions, and to you for watching this episode of Nature League. If you want to join in on the conversation, write your ocean questions in the comment section below, and I'll be answering them throughout the week.

And to keep going on life on Earth adventures with us each week, make sure to go to and subscribe. [BRIT LAUGHING].