1 / 29

Good Morning 10/20/15

Explore mechanisms, types, identification, and impacts of upwelling in the ocean, crucial for fishery and ecosystem health. Learn how wind, Coriolis Effect, and Ekman Transport contribute to this vital ecological process.

pdennis
Download Presentation

Good Morning 10/20/15

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Good Morning 10/20/15 Please grab the “Dissolved Nutrients” reading passage.

  2. Topic/Objective Upwelling in the World Ocean Essential Question: Why is upwelling such an important process?

  3. Upwelling in the World Ocean

  4. Presentation Points • Mechanisms that create ocean upwelling • Types of upwelling • Identifying upwelling on satellite-derived maps • Ecological and economic effects of upwelling

  5. Mechanisms that create ocean upwelling • Wind • Coriolis Effect • Ekman Transport

  6. Upwelling refers to deep water that is brought to the surface. Areas of upwelling are created by surface winds that pull water away from an area. This deficit of water on the surface invites water to come up from deeper regions.

  7. To understand upwelling, you must be familiar with how the Coriolis Force affects ocean surface currents. The Coriolis Effect acts on moving water, because it is not attached to the rotating Earth. As water flows over the rotating earth, it appears to deflect to the right in the Northern Hemisphere and the left in the Southern.

  8. Due to friction between the layers of water in the ocean and the Coriolis Effect, the net result of wind blowing across the surface of the water is transportation of a layer of water 90 degrees to the direction of the wind. This is known as Ekman Transport.

  9. 10/26/15 • SWBAT: Differentiate and explain the differences in types of upwelling. • Agenda: Slides 10 – 20 on AVID notes • Continue upwelling activity • Gentle reminder – Upwelling quiz on Wednesday.

  10. Types of Upwelling • Equatorial • Coastal • Seasonal

  11. 1. Equatorial Upwelling Water Flow Upwelling

  12. Look at the equator in the Pacific Ocean.

  13. 2. Coastal Upwelling (follow the black arrows)

  14. What’s the difference between Peru(A) and Colombia (B)? B A

  15. 3. Seasonal upwelling Wind Wind Onshore winds pile water up on shore, thus surface water will be forced downward. This is ‘downwelling’. Offshore winds take water away from shore, thus water from depth will upwell to the surface.

  16. The Monsoonal wind shifts in Oman create very different conditions. Wind Wind April, 1999 Onshore winds: Downwelling August, 1999 Offshore winds: Upwelling

  17. Identifying upwelling on satellite-derived maps • Sea Surface Temperature • Ocean Color

  18. The deep water that surfaces in upwelling is cold; by looking at Sea Surface Temperature maps we can identify cool upwelled water versus hotter surface water.

  19. Upwelled water also contains nutrients (nitrate, phosphate, silicate) and dissolved gases (oxygen and carbon dioxide) that are not utilized at depth because of a lack of sunlight.Now on the surface, these nutrients and gases help to fuel photosynthesis by small algae called phytoplankton.

  20. Phytoplankton photosynthesize using specialized color pigments called chlorophyll. Thus, “Ocean Color” maps are another way to identify areas of upwelling. Where on this ocean color map are high phytoplankton concentrations?

  21. Ecological and Economic effects of upwelling: • Upwelling leads to more phytoplankton • More phytoplankton leads to more fish • More fish lead to commercial fishing jobs and to more seafood

  22. Phytoplankton come in many shapes and forms. Collectively they form the base of oceanic food webs. Without upwelling many of the world’s fisheries would not thrive.

  23. Some climatic events can reduce upwellings. ~ El Nino

  24. Along Peru’s coast, an El Nino event decreases the coastal winds. Thus the upwelling from below is slowed. An El Nino condition results from weakened trade winds in the western Pacific Ocean near Indonesia, allowing piled-up warm water to flow toward South America.

  25. Even though upwelling areas account for only 1% of the ocean surface, they support 50% of the worlds fisheries.

  26. Rate of upwelling determines phytoplankton cell size. Duration of upwelling determines the total amount of phytoplankton. Productivity (phytoplankton growth) of an area is determined by the rate and the duration of upwelling. small vs. large fewvs. many

  27. RATE Low Medium High DURATION Long Short Classification of upwelling systems in terms of rate and duration: After Thurman, H.V. (1994)

  28. Moderate rates of upwelling for long duration (8 months or longer) provide the ultimate combination for a large fishery. • With too low or too high a rate, phytoplankton are small, so there is a trophic level between the algae and the fish….therefore the fish receive less energy.

  29. Upwelling and Fisheries January April July October Using this series of Sea Surface Temperature Maps from 1999, can you determine areas/times for possible fisheries? (Hint: Look at Peru’s coast in January and April. Look at the northwestern tip of Africa in July and October.)

More Related