Name: Date: Per: COASTAL UPWELLING - MONTEREY BAY CALIFORNIA (modified from The Maury Project, AMS) The ocean is composed of 3 distinct layers: the shallow surface mixed zone, the transition zone, and the deep zone. The shallow surface mixed zone is the warm surface water that is heated by the sun and mixed by waves, wind, and currents. The deep zone is the cool nutrient rich water that covers the ocean bottoms. The transition zone is the area between the shallow zone & the deep zone. The transition zone is marked by a change in temperature- thermocline and a change in salinity-halocline. Coastal upwelling is the upward movement of water from the deep zone that happens along coast-lines. This upwelled water is cold and nutrient rich. The nutrients brought to the surface encourage the high plankton productivity of the Monterey Bay area, which is why it is an excellent fishing locality. The upwelling water can be tracked by measuring its cool temperature, high nutrient content, high salinity and high density. Northwest winds: The strongest upwelling occurs when the Monterey area is experiencing winds from the northwest, which blow parallel to the coast of CA. When these winds are weak or the winds are from the south, the upwelling tends to stop and the warmer waters of the CA current move into Monterey Bay. The very large California Current travels southward along the CA coast from the North Pacific. Headlands: Observations of sea surface temperature from satellites show that upwelling is not uniform along the central California coast, but is strongest at the major headlands (point of land that stick out). The cold water of Monterey Bay comes primarily from the upwelling in the Point Ano Nuevo area, and then progresses south across the mouth of Monterey Bay toward the Monterey Peninsula. Coriolis effect: In the northern hemisphere the rotation of Earth causes surface water to move to the right of the wind. This movement to the right is known as the Coriolis effect. In the Monterey area, winds out of the northwest cause water to flow to the southwest, away from the coast. The water flowing offshore is replaced by the cool, nutrient rich water, which rises up into the coastal area from below, resulting in the upwelling phenomena. Bifurcated flow: When cool upwelling water rises to the surface t the headlands it departs in two directions, one tending offshore (to the west) and the other toward the equator (south). The upwelled water that flows westward, away from the coast, is immediately influenced by the Coriolis effect. The portion of the upwelled water that is traveling south is influenced by the Coriolis effect, the geography of the coastline, winds from the northwest and the California current.
DIRECTIONS Color the sea surface temperature map of Monterey Bay according to the colors listed below: Red-16 o C Orange-14 o C Yellow-12 o C Light blue-10 o Purple-8 o C Pink-15 o C Yellow/Orange-13 o C Green -11 o C Dark Blue-9 o C 1. Describe the location & shape of the cold surface water (9-11 ) by Pt. Ano Nuevo 2. The cold upwelled water moves westward out to sea & south across the bay toward Monterey. Why does it move in 2 directions? 3. Why is the cold upwelled water concentrated at Point Ano Nuevo & Point Sur? (think land shape) 4. Why is the Santa Cruz beach area so much warmer than the rest of the bay? (think shape & wind)
5. Besides following water temperature, what other measurable items could you use to follow the two paths of the upwelling water? 6. 6. There is a large power plant at Moss Landing that releases warm water, used for cooling its turbines, into Monterey Bay. Does this warm water show up on the map? Would you expect to find this warm water near the surface or on the bottom? Why?(think density of warm water) GRAPHING Plot the sea surface temperature in blue and the wind speed in red. Wind direction is the direction the wind is blowing from. Negative numbers on the table indicate winds from the south. Sea Surface Temperature & Wind Date (1989) Sea Surface Temp. o C Wind Direction May 23 10 N 3 May 25 10 N 8 May 27 9 N 10 May 29 9 N 8 May 31 9 N 4 June 2 10 S -1 June 4 12 S -4 June 6 13 S -3 June 8 12 N 7 June 10 11 N 5 June 12 10 N 8 June 14 10 N 7 Wind Speed Sea Surface & Wind ---CONTIUNED Date (1989) Sea Surface Temp. o C Wind Direction June 16 10 N 7 June 18 9 N 9 June 20 9 N 11 June 22 11 N 4 June 24 12 S -4 June 26 13 S -4 June 28 13-0 June 30 14 S -1 July 2 13 N 6 July 4 11 N 9 July 6 9 N 10 July 8 9 N 10 Wind Speed 6 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 2 4 6 8 May June July
Questions 1. What is the wind direction & speed during the times of coldest water (max. upwelling)? 2. What is the wind direction & speed during the times of warmest water (min. upwelling)? Conclusion Questions- Answer using your Map and Graph. 3. John Steinbeck wrote about the sardine canneries in Monterey in his book Cannery Row. The book describes the fishermen that netted these small plankton-eating fish by the hundreds of tons yearly until they were almost fished out. Sardines eat plankton & plankton is abundant 2 days after the start of upwelling. Wind from the North or South causes upwelling. Using the graph to determine the days you would fish for sardines. Explain your answer. 4. Squid are netted as they swarm in southern Monterey Bay to reproduce when the water is warmer than average. Fishermen turn on bright lights to attract and net them from midnight to six a.m. Based on your data which nights in June 1989 would you have picked to go squid fishing? Explain. 5. Suppose you were offering bay tours to the public and wanted your patrons to see the large, planktoneating basking sharks that visit Monterey Bay. Plankton need the cold, nutrient rich upwelling water to grow, so where would you go to find the cold water near Moss Landing? Explain your answer. Latitude & Longitude (use your map) 6. The Monterey Bay Aquarium has a remotely operated vehicle (ROV) that can go down into the Monterey Submarine Canyon to a depth of 4,000 m. The video shows "marine snow" (tiny particles of decaying organisms, feces, and plankton) drifting to the bottom. Marine snow starts to fall 2 to 3 days after upwelling. If you sent the ROV down at 37.0 N, 122.5 W during which days in June 1989 would you see the most marine snow? Why?