D. Suzuki_ Salmon and the forest

Summary

North America's temperate rainforests, a rare and endangered ecosystem, host the world's highest biomass due to its giant trees. Despite poor soil nitrogen levels, these forests thrive thanks to salmon, which carry nitrogen-rich nutrients from the ocean. After spawning, salmon are consumed by wildlife, particularly bears, who disperse nitrogen throughout the forest. This nutrient cycle supports tree growth, creating a symbiotic relationship between the ocean, rivers, and the forest, highlighting the interconnectedness of ecosystems.

Takeaways

• 🌳 North America is home to half of the world's temperate rainforests, which are incredibly rare and endangered ecosystems.
• 🌍 These rainforests cover less than 1% of the Earth's terrestrial area, yet they have the highest biomass weight of any ecosystem.
• 🌲 The large trees in these forests are a mystery given the nitrogen-poor soil, which is typically not conducive to such growth.
• 🐟 The key to the growth of these large trees is the salmon, which play a crucial role in the ecosystem despite the rain washing nutrients away.
• 🏞️ Salmon are born in the forest's freshwater rivers and are dependent on the forest for various stages of their life cycle.
• 🌊 After maturing in the ocean, salmon return to the rivers loaded with nitrogen-15, a heavier isotope that is abundant in the ocean.
• 🐻 Bears are significant contributors to the distribution of nitrogen in the forest, as they eat salmon and spread their waste, rich in nitrogen-15, throughout the area.
• 🦟 Flies and their maggots also play a role in the nitrogen cycle, as they consume salmon carcasses and then drop to the forest floor, enriching the soil.
• 🌱 Tree growth rings show a correlation between the presence of nitrogen-15 and periods of significant tree growth, indicating the importance of salmon as a fertilizer source.
• 🔄 The script describes a complex and interconnected system where the health of the ocean, salmon, rivers, lakes, and forests are all interdependent.

Q & A

What is considered one of the most rare and endangered ecosystems on the planet?

Temperate rainforests are considered one of the most rare and endangered ecosystems on the planet.

How much of the world's temperate rainforests are found in North America?

North America has half of all temperate rainforests in the world.

What is the significance of the temperate rainforest ecosystem in North America?

The temperate rainforest in North America, which runs from Southern Alaska to Northern California, has the highest biomass weight of living things of any ecosystem on the planet.

Why are the soils in temperate rainforests considered poor in nutrients?

The soils in temperate rainforests are considered poor in nutrients because the frequent rainfall washes a lot of the nutrients out of the soil.

How do large trees in temperate rainforests obtain the nitrogen they need if the soil is nitrogen-poor?

Large trees in temperate rainforests obtain nitrogen through the salmon, which bring nitrogen from the ocean when they return to spawn.

What role do salmon play in the nutrient cycle of the temperate rainforest ecosystem?

Salmon play a crucial role in the nutrient cycle of the temperate rainforest ecosystem by returning nitrogen from the ocean to the forest when they come back to spawn.

How do bears contribute to the distribution of nitrogen in the forest?

Bears contribute to the distribution of nitrogen in the forest by consuming salmon, and their feces spread nitrogen-15 throughout the forest.

What is the relationship between the nitrogen content in tree rings and salmon runs?

There is a clear relationship between the nitrogen content in tree rings and salmon runs, with wider tree rings corresponding to years with a large salmon run, indicating that salmon are a major source of fertilizer for the trees.

How do the nitrogen levels in salmon affect the food chain in the forest?

The nitrogen levels in salmon affect the food chain in the forest by providing a rich source of nitrogen-15, which is then consumed by other animals such as bears, birds, and insects, supporting the entire ecosystem.

What is the significance of the timing of the salmon runs and the hatching of flies in the forest?

The timing of the salmon runs and the hatching of flies is significant as it ensures that the flies, which are loaded with nitrogen-15, are available to feed the birds migrating from South America, thus linking the food chains across different ecosystems.

How does the script describe the interconnectedness of the ecosystems mentioned?

The script describes the interconnectedness of the ecosystems by highlighting how the ocean nourishes the salmon, which in turn fertilize the forest, and how this system is linked to the rivers, lakes, and even to the southern hemisphere, forming a single, complex system.

Outlines

00:00

🌲 The Secret of Temperate Rainforests' Fertility

The first paragraph introduces the rarity and endangered status of temperate rainforests, highlighting that North America hosts half of the world's temperate rainforests. These forests, despite being less than 1% of the planet's terrestrial area, have the highest biomass due to the presence of large trees. The mystery of how these trees thrive in nutrient-poor soil, especially in nitrogen, is revealed through the life cycle of salmon. Salmon are born in freshwater rivers within the forest, and their journey to the sea and back is crucial for the ecosystem. They accumulate nitrogen-15 from the ocean, which is then reintroduced into the forest ecosystem when they return to spawn and are consumed by predators like bears and birds. This process fertilizes the forest, particularly evident in the tree rings' nitrogen-15 content, which correlates with years of abundant salmon runs.

05:01

🐟 The Salmon's Role in Ecosystem Connectivity

The second paragraph emphasizes the interconnectedness of the ecosystem, where the salmon play a pivotal role. The salmon, after being born in the forest and spending time in the ocean, bring back nitrogen-15 when they return to spawn. Their bodies, once consumed by predators, fertilize the forest floor, providing a rich source of nutrients for the trees. This cycle not only supports the growth of trees but also sustains a complex food web involving insects, birds, and other animals. The paragraph illustrates how the health of the forest is tied to the health of the ocean and how the salmon act as a vital link between these two ecosystems, creating a harmonious and self-sustaining cycle.

Keywords

💡Temperate Rainforests

Temperate rainforests are a rare and endangered ecosystem characterized by moderate temperatures and high rainfall. They are home to a diverse range of flora and fauna. In the video, it is mentioned that North America hosts half of the world's temperate rainforests, which are crucial for their high biomass weight and biodiversity. The script highlights the unique relationship between these forests and the salmon that inhabit them, illustrating the interconnectedness of the ecosystem.

💡Biomass

Biomass refers to the total mass of all living organisms in a given ecosystem. The video emphasizes that temperate rainforests have the highest biomass weight of any ecosystem on Earth, largely due to the presence of large trees. This concept is central to understanding the importance of these forests and their ability to support a vast array of life.

💡Nitrogen

Nitrogen is an essential nutrient for plant growth, and it is a key component of proteins and DNA. The script discusses the paradox of nitrogen-poor soil in temperate rainforests and the presence of large trees, which require nitrogen for growth. The role of nitrogen, particularly nitrogen-15, is highlighted in the video as it is brought into the ecosystem by salmon, contributing to the growth of the trees.

💡Salmon

Salmon are anadromous fish that are born in freshwater rivers, migrate to the ocean, and return to their natal streams to spawn. In the video, salmon are described as a vital link in the ecosystem, not only for their role in the food chain but also for their contribution of nitrogen to the forest through their bodies after they spawn and die.

💡Nitrogen Isotopes

Nitrogen isotopes, specifically nitrogen-14 and nitrogen-15, are variants of the nitrogen element with different numbers of neutrons. The video explains that while nitrogen-14 is the predominant isotope in the soil, salmon accumulate nitrogen-15 from the ocean. This distinction allows scientists to trace the source of nitrogen in the forest, demonstrating the salmon's role in fertilizing the ecosystem.

💡Spawning

Spawning is the process by which fish release their eggs and sperm into the water to reproduce. The video describes how salmon return to the rivers to spawn, which is a critical moment for the ecosystem as it is when they introduce nitrogen-15 into the forest. The act of spawning is not only essential for the continuation of the salmon species but also for the health of the forest.

💡Bears

Bears are mentioned in the video as significant predators of salmon and as key vectors in the distribution of nitrogen within the forest. They are depicted as gathering in large numbers to feed on salmon during the spawning season, and their feces, which contain nitrogen-15, fertilize the forest floor. This behavior highlights the role of bears in the nutrient cycle of the ecosystem.

💡Invertebrates

Invertebrates are animals without a backbone, and they play a crucial role in the decomposition process. The video mentions that after bears consume salmon, the remaining carcasses are quickly utilized by invertebrates such as beetles and salamanders. These organisms help break down the salmon, releasing nitrogen-15 into the soil and contributing to the forest's fertility.

💡Fungus and Bacteria

Fungus and bacteria are decomposers that break down organic matter. In the context of the video, they are described as consuming the salmon that die and sink to the bottom of the streams. This decomposition process enriches the water with nitrogen-15, providing a food source for the emerging baby salmon and further illustrating the interconnectedness of the ecosystem.

💡Interconnectedness

Interconnectedness refers to the complex web of relationships between different components of an ecosystem. The video script uses the example of the salmon life cycle and its impact on the forest to illustrate how the health of the oceans, rivers, and forests are all linked. This concept is central to understanding the importance of preserving each part of the ecosystem for the overall health of the planet.

Highlights

Temperate rainforests are among the rarest ecosystems globally, covering less than 1% of the Earth's terrestrial area.

North America hosts half of the world's temperate rainforests, stretching from Southern Alaska to Northern California.

These rainforests have the highest biomass weight of any ecosystem due to the presence of large trees.

The soil in temperate rainforests is poor in nitrogen, a critical nutrient for tree growth.

Salmon play a key role in the ecosystem, being born in freshwater rivers within the forest.

Clear-cutting forests leads to a significant decline in salmon populations, highlighting the interdependence between salmon and the forest.

Salmon require cool waters and food from the forest during their early life stages.

The forest also helps to maintain the quality of the spawning gravel, crucial for salmon reproduction.

Salmon accumulate nitrogen-15 from the ocean during their time at sea, which is different from the nitrogen-14 found on land.

When salmon return to spawn, they bring a rich source of nitrogen-15 to the forest ecosystem.

Predators such as bears, eagles, and wolves consume salmon, spreading nitrogen-15 through their feces in the forest.

Bears, in particular, are significant in distributing salmon-derived nitrogen throughout the forest.

Flies and their larvae (maggots) also play a role in spreading nitrogen-15 by consuming salmon carcasses.

The timing of salmon runs coincides with the arrival of migratory birds, providing a critical food source for them.

Tree growth rings show a correlation between wide rings (indicating growth) and years with abundant salmon runs.

Salmon that spawn and die in the water contribute to a nutrient-rich mat of fungus and bacteria, feeding the next generation of salmon.

The ecosystem demonstrates an intricate web of connections between the oceans, rivers, lakes, forests, and migratory birds.

Transcripts

one of the most rare and endangered

ecosystems on the planet are temperate

rainforests North America has half of

all temperate rainforests in the world

it's less than 1% of the land the

terrestrial area of the planet and in

North America we have pinched between

the Pacific Ocean and the coastal

mountains we have a temperate rainforest

that runs from Southern Alaska to

Northern California has the highest

biomass weight of living things of any

ecosystem on the planet and that's

because we have big trees and one of the

mysteries has always been how can we get

such big trees when it rains a lot it's

a rain forest and the rain washes a lot

of the nutrients out of the soil the

soil in fact is very poor in nitrogen so

how can you have a nitrogen poor

ecosystem and yet these gigantic trees

that are built on nitrogen and carbon

well it turns out the secret is the

salmon you see the salmon are born in

the forest in in freshwater rivers and

we know that the salmon need the forest

because if you clear-cut a watershed

where the salmon spawn salmon

populations plummet and usually

disappear the salmon need the forest for

the canopy to keep the waters cool

because the babies are very sensitive to

temperature there we need the forest to

provide the feed when the babies are are

getting ready to go down to the ocean

they need to feed and we need the forest

to hold the soil so that doesn't spoil

the spawning gravel so we knew that but

now the interesting thing is if you look

at the nitrogen on the land it's almost

exclusively nitrogen-14 which is a the

normal isotope of nitrogen when you look

in the oceans the nitrogen has also has

a large component of nitrogen 15 which

is slightly heavier it's got extra

Neutron in it and you can tell nitrogen

15 from nitrogen 14 in your in your

instruments so baby salmon born in the

forests protected by the forests they go

out to sea there are five species of

salmon on the coast and depending on the

species they stay out to sea for two to

five years all the while growing and

loading up with nitrogen

theme from the oceans so when they come

back to spawn they are loaded like

little bullets of nitrogen 15 fertilizer

and as they come into the estuaries is

the killer whales and the seals are

eating them then they hit the river and

the Eagles in the way and the Bears and

the wolves are all eating the salmon and

as they poop in the woods they're

spreading nitrogen 15 throughout the

forest and one of the major vectors are

bears the Bears

they'll fish together they're a solitary

animal but when the salmon are running

they'll fish together in the same pool

but the minute they grab one they take

off they don't want to eat it with the

other bears around and they'll go up 150

meters on either side of the river they

sit down they eat the best parts which

you all know is the brains and the belly

and the eggs and usually they'll leave

the carcass the rest of the carcass so

about half the salmon is left there they

go back for another one

and a bear will take about 600 salmon

out of the river in a year and that

salmon carcass it's left is immediately

pounced on by salamanders and beetles

and Ravens and everything but the major

vector is flies so the Flies lay their

eggs on the carcass within a few days

that carcass will just a seething mass

of maggots which are consuming that

flesh loading up with nitrogen 15 and

then they drop to the forest floor and

over winter as pupae and the next spring

as they hatch in the trillions it's just

at the time that the birds from South

America are coming through on their way

to the Arctic to have their babies so

the timing is that the salmon are now

feeding the Flies which are programmed

then to hatch just at the time that they

will feed the the birds from South

America when you look at the trees you

can take a core of the trees and pull it

out you can show there our fat rings

which is a lot of growth or skinny rings

you can measure the amount of nitrogen

15 in the Rings and show when there's a

fat ring there's way more nitrogen 15

and then we've got government records

going back 50 years and you can show

when there's a fat ring that was the

year that was

big run of salmon so it's very very

clear the salmon are the major pulse of

fertilizer that the trees are getting

the trees respond to that many of the

the salmon spawn and then die in the

water they sink to the bottom and if you

come up a stream a few weeks later the

bottom is covered with a thick mat of

fungus and bacteria that are consuming

the flesh and the fungus and bacteria

are eaten by by invertebrates insects

and things when the babies emerge from

the gravel for months later the baby

salmon the water is filled with food

that is loaded with nitrogen 15 that

comes from the parents bodies so you see

this unbelievably beautiful system of

interconnectedness where the oceans give

burped you don't feed the salmon and

their oceans are linked to the rivers

and lakes which are linked to the the

forests and are linked to the southern

hemisphere all of that is a single

system