(soft calming music) Isn't it amazing how plants, animals, and the environment work together?

It's so cool how the biotic and abiotic factors form such complex ecosystems.

This is the Coastal River Room at the Virginia Aquarium and Marine Science Center in Virginia Beach.

This exhibit demonstrates a coastal river ecosystem, and all the biotic and abiotic components needed to create a healthy habitat.

Today, we will explore ecosystems, and how the organisms in the ecosystem work together.

It's the subject of this episode of "Spotlight Earth".

(soft calming music) I'll be back with more from the aquarium later.

But for now, let's check in with the studio, for a systemic take on how ecosystems are organized.

Thanks, Hales.

I love the Aquarium and Marine Science Center.

Don't you?

I love the aquarium.

So yes, we're talking ecosystems.

And scientists have created a nomenclature.

A nomenclature is a naming system.

In this case, for different units of life in ecosystems.

The smallest unit of life is the individual.

This is a singular plant or animal in an ecosystem.

The next unit is a population.

A population is all of the individuals of a species living in a specific area.

If we go larger, we reach the community level.

All of the populations come together to form a community, which is a large collection of all of the interacting populations in a given area.

On a previous episode, we explored the differences between biotic and abiotic factors in the environment.

Remember, biotic factors are living things like plants, animals, and bacteria.

Abiotic factors are non-living components, like water, soil, and atmosphere.

Ecosystems are a combination of abiotic and biotic factors.

They are complex communities of organisms interacting with their environment.

And if some small part of the ecosystem changes, it can have rippling effects across all of the biotic factors.

To learn more about these complicated relationships, let's check back in with Hales, with some expert info on the subject.

(soft acoustic music) I'm here with Chris Witherspoon, the Vice President of Science Education at the Virginia Aquarium.

Chris, can you tell us a little bit more about the ecosystem we see behind us?

Sure.

You're looking at the Chesapeake Bay Aquarium.

The fishes in here represent what you would see near the mouth of the Chesapeake Bay, or the southern or lower bay, as the it's referred to.

This is the part of the Chesapeake Bay that is the saltiest.

The fish you see here are the ones that are more of a marine species.

They would migrate in and out, for the most part.

They like the saltiest water.

But as you move upstream, you're gonna find, at the very head of the bay, freshwater, and obviously if you go to the tributaries or rivers, they're gonna have freshwater too.

And in between is that special water, you've probably heard the word "brackish".

And brackish refers to water that's a lower salinity water than ocean water.

Another abiotic factor is sunlight.

And because of the bay's depth, sunlight is a very important abiotic factor.

For most of the bay, 50% of it is 20 feet deep or less.

So, we're talking about a shallow body of water.

And what that means is sunlight can penetrate down to most of the bottom areas, which is feeding plant life, basically.

Providing the life they need for photosynthesis.

And what we find is we have what are called submerged aquatic vegetation.

A lot of things depend on it for shelter, like blue crabs that are shedding, and a lot of juvenile fish.

So, those are examples of abiotic or non-living factors.

What are the biotic factors?

The things living in the bay?

So, biotic factors would be the animals, the marsh, which is gonna provide habitat for a certain type of animal, particularly nursery areas for young.

Then of course, we have oyster reefs, where the oysters grow together to form a reef that provides habitat, as well as a source of food for many animals.

And a lot of it connects to that whole salinity thing that we started with.

What can live in salt, what can live in brackish?

What can live in freshwater?

So as you can see, the biotic and abiotic factors are very dependent on one another.

But what would happen if say, an abiotic factor changed?

(thunder rumbles) So if we were to have a large hurricane, and this has happened in the past.

There was just a ton of rain that was being dumped in the Chesapeake Bay watershed.

If you get all this freshwater coming down in the bay, it makes the freshwater and brackish water move south, sort of pushes the saltwater out.

So there's less space for saltwater critters.

So it could have an effect on any of the saltwater animals that can't move with that change.

And the reverse happens, if we have a drought.

Then we don't have as much freshwater coming in, and saltwater moves farther up in the bay.

So some of the fresh things that like brackish or fresh, have to retreat back, or they wouldn't survive.

Another changing abiotic factor is water temperature.

And unfortunately, this is not hypothetical.

So we start thinking about climate change, and the fact that our air temperature's getting warmer, and so the water temperature is gonna start warming up.

So, we might start seeing changes in the community of plants and animals.

Eelgrass is very important submerged aquatic vegetation species, but it really is at its southern limit where we are.

And now with temperature rising, it's really not the best environment.

So, we may see that disappearing from the bay.

That has great implications for things like crabs, and and the habitat that animals need.

We would also have some, as it warms up, some of the cooler water species that we've perhaps seen in the past, may not be as prevalent.

But, they may be replaced by some warmer water.

So, it's not to say that all of a sudden there's nothing out there, it's probably gonna be more of some things would disappear, but there may be other species that begin to change their range because it's warmer up here.

So the bay is a super important and super delicate environment.

We can protect it by planting native plants throughout the Chesapeake Bay watershed, and by restoring wetlands that act as a buffer in protecting against runoff.

We can also be vigilant in how we care for our lawns.

As fertilizer runoff is one of the most destructive issues for the Chesapeake.

A clean, healthy bay means improved public health, better economic outcomes for Virginians, and better fishing and recreational opportunities.

So much to explore here, so, I'm gonna send it back to the studio, and take a stroll around.

Bye, everyone.

Thanks, Hales.

Enjoy!

While Hales is doing that, let's get back to our exploration of ecosystems.

Organisms within an ecosystem interact with each other too, both within their species and between species.

Symbiotic relationships are close, long-term associations between organisms of different species.

We categorize these interactions by whether or not they benefit the individual, or harm the individual.

Commensalism is when one organism benefits, and the other is not affected by it.

For example, the remora fish attaches itself to a shark.

When a shark is done eating a meal, the remora detaches to eat the shark's leftovers.

The shark doesn't even know it's there.

So, the remora fish benefits, but the shark is unharmed.

That's commensalism.

Mutualism is when different organisms, both benefit from the relationship.

For example, honeybees gather pollen, and help spread that pollen to other flowers for pollination.

And the bees use the pollen to make honey, which is their food source.

Also, consider the clownfish and the sea sea anemone.

The clownfish is covered in a thick layer of mucus, and can hide from predators among the anemones.

The anemones benefit because the clownfish provides the food to the anemones, and help rid of its harmful parasites.

In these cases, both organisms mutually benefit from the relationship.

That's why it's mutualism.

Have you ever heard someone called a parasite?

You know, that's definitely not a compliment.

A parasite is an organism that lives on or in another organism.

And gets his food normally at the expense of the host.

(hand slaps) (whimsical calming music) Got it!

A mosquito is an example of a parasite.

It takes our blood when biting us.

We don't get benefits from it, and it makes us really itchy.

A tapeworm is another example of a parasite.

If you eat its eggs, it can start growing inside of you, through your intestines, making you very sick, and keeping nutrition from you.

If left untreated, it can kill you.

Pretty gross.

(host chuckles) It's important to understand the different relationships in ecosystems, and to learn about different ecosystems here in Virginia.

I love that when everything is working together, it keeps our ecosystem thriving.

That's our goal here.

Thanks for watching "Spotlight Earth".

(soft lighthearted music)