Category Archives: Oceans

Why We Study Earth Science

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Frequently students will ask “why do we have to learn science?” and in particular Earth Science. Seems they’d rather dissect a frog. But when tragedies like earthquakes and tsunamis strike, like the recent catastrophe in Japan,  we see the importance of this line of study.

Earth science helps us to better predict these events, develop warning systems, create buildings that can withstand the stress and ultimately save lives. In this situation we also have to understand the consequences of our energy choices, both at home and abroad. With this recent news clip from ABC News, we see how our understanding of ocean currents plays a role also.

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Massive 8.3 Ocean Earthquake

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Today’s South Pacific earthquake is an example of Earth’s interacting spheres. The heat from within the Earth powered the magnitude 8.3 quake whose epicenter was 21 miles below the bottom of the Pacific Ocean. The shifting of Earth’s crust resulted in a tsunami killing 23 people on surrounding islands.

Here’s an excerpt from Discovery News about today’s quake.

Sept. 29, 2009 — A powerful earthquake with a magnitude of up to 8.3 struck off the South Pacific island nation of Samoa on Tuesday, triggering a tsunami as coastal residents fled to higher ground.

The Pacific Tsunami Warning Center said waves 1.57 meters (five feet) tall hit American Samoa, while 0.7 meter waves were recorded in Samoa.

The center had earlier issued a tsunami warning for a large swathe of the South Pacific including Fiji, New Zealand and Tonga after the U.S. Geological Survey reported a 7.9 magnitude quake.

The center later said an 8.3 magnitude quake had been recorded at a depth of 33 kilometers (21 miles). It was not immediately clear if this was the same quake and the USGS’s website did not provide exact details of its location.

“Sea level readings indicate a tsunami was generated,” said a statement from the Pacific Tsunami Warning Center.

Related Content:

“It may have been destructive along coasts neat the earthquake epicenter and could alo be a threat to more distant coasts. Authorities should take appropriate action in response to this possibility.”

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Waves From Bill

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I was sitting at the table Saturday morning having breakfast with my wife, in the background  the weather channel was talking about the waves that we could expect from hurricane Bill, then close to 1,000 miles away off the coast of Virginia. Hard to imagine that something that far away could have a significant affect on the beaches of Florida.

Smyrna WavesAbout an hour later we were standing on the beach in New Smyrna. Waves were running 5-8 feet and breaking far from the waters edge. A few people played near shore where one minute you were in ankle deep water and the next almost to your waist. The pull of the water as it ran back out to sea was amazing!

Unfortunately later that day the power of the waves took the life of a body surfer in New Smyrna and today waves from the same storm may have claimed more lives in Maine.

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How are you connected to the ocean?

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Take two breaths.

One came from the ocean.
Image Credit: Austin Tomlin, Creative Commons

Image Credit: Austin Tomlin, Creative Commons

It’s true! Roughly half of the oxygen we breathe is produced by phytoplankton, tiny single-celled plants that live in the sea. That fact alone means that you – and all life on Earth – depend on the ocean for survival every minute of every day. In fact, no matter how far we may live from the coast, the ocean is important to our daily lives in countless ways. The ocean stabilizes our climate and weather patterns and is vital to the global cycle that supplies us with clean drinking water. It provides seafood to millions of people, and studying the wild diversity of life beneath the waves has helped us produce medicines and other important products. For those who live near the water, the ocean offers direct opportunities for employment, transportation, and recreation.

Click here to celebrate Ocean and Water with Year of Science!

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El Nino

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Here is some excellent information on El Nino. Click on the image below.

I decided to do a quick recap of our discussions about El Nino (actually this includes today and tomorrow). This might help with your notes.

Ocean circulation and how it changes during El Nino. 

  • Factors that influence currents: winds, land masses, Coriolis effect
  • Normal non-El Nino Pacific currents: strong easterly trade winds, easterly equatorial currents, mounding of warm surface waters in the western Pacific, cold deep water upwelling along South America
  • El Nino changes: weak or reversed trade winds, equatorial currents reverse (flow down hill) towards east, central and eastern Pacific warm, western Pacific cools, upwelling ceases.

Relationship between ocean and atmospheric circulation during El Nino:

  • Changes in pacific equatorial currents and warming of central and western Pacific affects Walker Cell circulation. Normal Walker Cell circulation collapses and warm moist air raises over the central and eastern Pacific, low pressure moves east.
  • Jet streams move south across US
  • Changes in these circulations affect the weather around the globe

Weather impacts in Central Florida:

  • Changes to jet stream results in fewer hurricanes due to increase wind shear aloft, hurricanes that do form tend to be pushed more towards the north Atlantic.
  • Temperatures do not vary significantly, some slight cooling in winter months of about 2-3°
  • Increased cloud cover and rainfall, an additional 10 inches (30%). This may have some negative impacts on crops and tourism, however it helps to recharge the aquifers and reduce the number of brush fires
  • Increased likelihood of tornadoes

Relationship between ocean circulation, the aquatic food chain and El Nino:

  • During non El nino years upwelling occurs along the west coast of south America. This upwelling bring nutrient rich cold bottom waters to the surface where it helps feed small organisms called phytoplankton. Phytoplankton are producers and form the bottom rung of the ocean food chain.
  • During El Nino years the upwelling stops which results in significantly less phytoplankton. The reduced levels of phytoplankton means each level higher up on the food chain will have insufficient food.

How El Nino changes might affect the food chain/production in Florida:

  • While El Nino has a significant negative affect on the fishing industry along the west coast of South America, it does not have a significant impact on fishing in Florida. El Nino is an event in the Pacific ocean not the Atlantic. However it may affect imports of certain fish and fish products raising prices due to decreased catch
  • El Nino does affect our winter crops in Florida with increased rainfall and reduced sun. Increased rain might delay planting or increase diseases. Different varieties may need to be planted or different planting techniques used. El Nino even affects cattle raised in Florida, as pasture area is less productive.
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Ocean Studies

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We took a very different route towards learning this time. We started with a simple “I Wonder” question “I wonder what causes ocean circulation?”. No introduction from the teacher, no movies, no textbooks, no experiments, not even the internet, just students discussing their ideas.

Then we combined ideas from all the classes, asked a few questions of each other to clarify thinking and selected what we (students) thought were the top 5 most significant factors causing water to move through the oceans. Here’s the list (6 listed because of variations between classes):

  • Wind
  • Temperature
  • Earth’s rotation
  • Moon’s gravity
  • Plate tectonics
  • Water Cycle

This is a great list! It shows your ability to apply prior knowledge to new situations, think logically, evaluate various options and engage in debate. I am proud of how well you did.

Lastly you had to do some textbook research into these and present your findings to the class. This had mixed results some very good and others not so good. Textbook research doesn’t seem to be a mastered skill yet, but we’ll work on it. If you were perfect at everything what would you need me for?

Now let’s have some more fun — “scientific messing around”. Let’s play with water!

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