2 ecological history

BIODIVERSITY IN THE GULF OF MAINE Why does one of the

most biologically productive habitats in

the North Atlantic have such low biodiversity?

1. The Gulf of Maine is relatively young in the scope of geologic time, and has had a limited amount of time to develop a diverse ecosystem.

Why is biodiversity low in the Gulf of Maine?

1. The Gulf of Maine is relatively young in the scope of geologic time, and has had a limited amount of time to develop a diverse ecosystem.The Bering Strait opened when tectonic

activity pulled North America and Asia apart roughly 3 million years ago, during the mid-Pliocene.

Why is biodiversity low in the Gulf of Maine?

The Gulf of Maine began forming roughly 190 million years ago when the supercontinent Pangea broke apart. See the previous lesson on Geologic History to learn more about Pangea.

1. The Gulf of Maine is relatively young in the scope of geologic time, and so has had limited time to develop a diverse ecosystem.

The Bering Strait opened when tectonic activity pulled North America and Asia apart roughly 3 million years ago, during the mid-Pliocene.

Why is biodiversity low in the Gulf of Maine?

Asian and North American plates pulled apart roughly 3 million years ago to form the Bering Strait, opening a gateway for North Pacific species to travel through the Arctic Ocean, down the North Atlantic, and eventually into the Gulf of Maine for the first time.

BERING STRAIT

GULF OF MAINE

The Gulf of Maine began forming roughly 190 million years ago when the supercontinent Pangea broke apart. See the previous lesson on Geologic History to learn more about Pangea.

1. The Gulf of Maine is relatively young in the scope of geologic time, and so has had limited time to develop a diverse ecosystem.

The Bering Strait opened when tectonic activity pulled North America and Asia apart roughly 3 million years ago, during the mid-Pliocene.

Why is biodiversity low in the Gulf of Maine?

As an older ocean, the Pacific Ocean contained more advanced species than the Atlantic did when the Gulf of Maine formed. So, when the Bering Strait opened, it offered a source of biodiversity previously unavailable to the Gulf of Maine.

Why is biodiversity low in the Gulf of Maine?

1. The Gulf of Maine is relatively young in the scope of geologic time, and so has had limited time to develop a diverse ecosystem.

Why is biodiversity low in the Gulf of Maine?

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to develop a diverse ecosystem.

2. Few species can withstand the temperature extremes in the Gulf of Maine.

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to develop a diverse ecosystem.

2. Few species can withstand the temperature extremes in the Gulf of Maine.

Why is biodiversity low in the Gulf of Maine?

The Gulf of Maine receives a contrasting mix of warm currents from the south and cold Arctic currents from the north. Many species cannot survive these temperature extremes. As a result, the Gulf serves as the northern-most boundary for many temperate species, the southern-most boundary for many Arctic species, and the prime range for far fewer species.

Approximate temperate range

Approximate arctic range.

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to develop a diverse ecosystem

2. Few species can withstand the temperature extremes in the Gulf of Maine.

3. North American glaciers advanced into the Gulf of Maine during the last ice age, compressing habitats and causing local extinctions.

Why is biodiversity low in the Gulf of Maine?

Why is biodiversity low in the Gulf of Maine?

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to develop a diverse ecosystem

2. Few species can withstand the temperature extremes in the Gulf of Maine.

3. North American glaciers advanced into the Gulf of Maine during the last ice age, compressing habitats and causing local extinctions.

Why is biodiversity low in the Gulf of Maine?

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to accumulate a diverse group of species.

2. Few species can withstand the shallow water temperature extremes in the Gulf of Maine.

3. North American glaciers encroached on the Gulf of Maine roughly 18,000 years ago during the last ice age, compressing habitats and causing local extinctions.

Not all species survived the drastic glacial conditions.

Why is biodiversity low in the Gulf of Maine?

The Laurentide Ice Sheet retreated completely from the Gulf of Maine roughly 13,000 years ago, leaving behind a changed landscape and a smaller food web.

1. The Gulf of Maine is relatively young in the scope of geologic time, so it has had limited time to accumulate a diverse group of species.

2. Few species can withstand the shallow water temperature extremes in the Gulf of Maine.

3. North American glaciers encroached on the Gulf of Maine roughly 18,000 years ago during the last ice age, compressing habitats and causing local extinctions.

Why does one of the most biologically

productive habitats in the North Atlantic have such low biodiversity?

Why does one of the most biologically

productive habitats in the North Atlantic have such low biodiversity?

11. The Gulf of Maine is young.

2.

3.

Why does one of the most biologically

productive habitats in the North Atlantic have such low biodiversity?

1. The Gulf of Maine is young.

2. Few species can stand the temperature extremes.

3.

Why does one of the most biologically

productive habitats in the North Atlantic have such low biodiversity?

1. The Gulf of Maine is young.

2. Few species can stand the temperature extremes.

3. Glaciers from the last ice age caused mass extinctions and habitat loss.

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Think of an ecosystem as a drawer of socks, in which different colored socks represent different species.

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Think of an ecosystem as a drawer of socks, in which different colored socks represent different species.

Now imagine that certain colors are randomly banned from your dress code each week. No matter how many socks you have, you can only prepare for this unpredictable pressure on your sock selection by maintaining a great diversity of colors in your sock drawer.

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Think of an ecosystem as a drawer of socks, in which different colored socks represent different species.

Now imagine that certain colors are randomly banned from your dress code each week. No matter how many socks you have, you can only prepare for this unpredictable pressure on your sock selection by maintaining a great diversity of colors in your drawer.

If you have a drawer full of only blue socks, for example, you’ll be vulnerable on days when blue socks are unexpectedly banned.

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Think of an ecosystem as a drawer of socks, in which different colored socks represent different species.

Now imagine that certain colors are randomly banned from your dress code each week. No matter how many socks you have, you can only prepare for this unpredictable pressure on your sock selection by maintaining a great diversity of colors in your sock drawer.

If you have a drawer full of only blue socks, for example, you’ll be vulnerable on days when blue socks are unexpectedly banned.

Peers with lots of different colored socks are not quite as vulnerable.

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Similarly, ecosystems with high biodiversity can better maintain ecological stability when one particular species is 'banned' or eliminated due to unexpected environmental conditions.

vs.

MORE STABLE

MORE VULNERABLE

vs.

Ecosystem A Ecosystem B

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Similarly, ecosystems with high biodiversity can better maintain ecological stability when one particular species is 'banned' or eliminated due to unexpected environmental conditions.

vs.

MORE STABLE

MORE VULNERABLE

For example, imagine that an an unexpected turn of water currents brings this shark through the two ecosystems above. The shark is hunting for the turquoise fish. Which ecosystem will be more vulnerable to the shark’s visit?

Ecosystem A Ecosystem B

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

vs.

MORE STABLE

MORE VULNERABLE!

Ecosystem A Ecosystem B

vs.

YUM.

MORE VULNERABLE

Ecosystem B

How does its low biodiversity make the

Gulf of Maine sensitive to environmental

change?

Ecosystem A Ecosystem B

Ecosystems with low biodiversity are less balanced and more vulnerable to unexpected environmental conditions than ecosystems with high biodiversity.

MORE VULNERABLE!