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Place 02 · Monterey Bay · Chapter 2 of 7
Cold Water Rising
In June the sea at Monterey is about as cold as it is in January. That is the good news.
About 15 minutes · 1 video · 1 live map · 2 quick activities
Start here
The bay turns itself upside down every spring
From about March to September, the northwest wind pushes the warm surface water of the bay out to sea, just as Chapter 1 predicted. Cold water from a hundred meters or more below rises to take its place, and it arrives loaded with fertilizer. That is upwelling, and it turns this coast into one of the most productive stretches of ocean on Earth.
Watch this
See it move
Hakai Institute — What is Upwelling? Short and sharp: from wind to whale food. Watch where the cold water comes from.
While you watch, look for
- Which way the surface water goes when the wind blows along the coast
- What the deep water brings up with it
- Something you did not expect. Hold onto it.
The short version
Three things going on here
The switch
Wind on, cold up
When the spring and summer northwest winds blow, Ekman transport shoves surface water offshore and cold water rises along the coast: upwelling. In winter the winds weaken or swing around to come from the south, water piles against the shore and sinks: downwelling.
The fog
Cold sea, gray summer
Warm, damp air drifting in over the upwelled water is chilled until its moisture condenses into fog. That is why Monterey’s summer mornings are famously gray while the inland valleys bake. The cold sea makes its own weather.
The fertilizer
Deep water is rich water
Dead plankton and animal waste sink and rot in the dark, releasing nitrate, phosphate and iron where there is no light to use them. Upwelling lifts that fertilizer back into the sunlight, and life booms until the scarcest one, the limiting nutrient, runs out. That is why cold water here means rich water.
Photos: Circe Denyer, ArtHouse Studio, Gerard Whelan / Pexels
Play with it
Take the sea’s temperature right now
This live map colors the sea surface by temperature. Click the water just off Monterey, then spin the globe east and click the Atlantic off Virginia, at the same latitude, and then off Maine.
Live map: earth.nullschool.net by Cameron Beccario, using NOAA and other public data.
Two questions to answer while you are in there
- How much colder is the sea at Monterey than the Atlantic off Virginia, at the same latitude, today?
- Look along the California coast. Is the coldest water right against the shore or far out at sea, and why?
Try it yourself
Check yourself
Try it
The Upwelling Story
Drag seven words into place to tell the story of an upwelling summer.
Try it · interactive
Upwelling Switch
Turn up the spring northwest wind and watch cold, nutrient-rich water rise along the coast, the plankton bloom, and the sea surface temperature at Monterey drop.
Open the Upwelling Switch in its own window (opens in a new tab).
Words you will hear
Four terms, that is all
Upwelling
Cold deep water rising to the surface
Downwelling
Surface water piling up and sinking
Nutrient
A chemical living things need to grow
Limiting nutrient
The scarcest nutrient, which caps growth
Check your understanding
Practice the whole chapter
Everything in this chapter, in eight quick questions. Retry as often as you like. Read the feedback on every answer, right or wrong, because that is where the learning is.
Practice
Practice: Cold Water Rising
Eight questions covering the video, the three cards, the four terms and the interactive above.
If you want more
Go deeper
- Webb 9.5 — Currents, Upwelling and Downwelling — LibreTexts · 10 minutes
- Oceanography 101 (MiraCosta) 9.9 — Upwelling and Downwelling — LibreTexts · 8 minutes
- Webb 7.3 — Factors Influencing Production — LibreTexts · nutrients and limiting factors · 10 minutes
Photo credits (Pexels): Gary Sylvester, Stephen Leonardi, Circe Denyer, ArtHouse Studio, Gerard Whelan.