OCEANOGRAPHY 2007 TEST

Transcription

1 OCEANOGRAPHY 2007 TEST This event is to be run in stations, 7 stations total, 3 minutes apiece. You should run 2 sets of stations if you have more than 7 teams. The other students will be taking a portion of the test that does not require a station. Station 1 Needs: ph meter at a station (2 if you run two sets of stations) two samples of water, one fresh water with a ph around 7 (can be slightly less) and a sample of seawater which should have a ph of around 8.2. The recipe for seawater: about ½ cup Instant Ocean per gallon distilled water. Tell students if they finish a station early they should work on questions at the end

2 Station 1: a) Which sample is seawater? b) What causes the ph in the seawater to be higher at the surface and lower at the depths? c) Why is seawater s ph so different from that of fresh water? Be specific.

3 Station 2: a) Identify the objects labeled A, B and C A: B: C: b) Explain the formation of object B. c) What two things must be present for an atoll to eventually form?

4 Station 3: a) Label the formations in this painting by Monet. A B C b) Why don t you see many of these formations off the coast of North Carolina? c) In the formation process, which of the three formations comes first?

5 Station 4 a) What is the structure in the picture? b) How does it form? c) Why are they important?

6 Station 5 a) Explain the trend for Carbon Dioxide with depth according to the figure. b) At what depth does the oxygen concentration start to increase? c) Give an explanation for this observation.

7 Station 6 a) What is the main difference between the surface ocean temperatures in January of 2000 and January 2007? b) What phenomena can be attributed to each of these images? Jan 2000: Jan 2007: c) What happens to the trade winds when an El Nino forms?

8 Station 7 a) What title would you give this picture? b) Propose a mechanism for the formation of this phenomena in nature. c) What seafloor feature do the phenomena in this picture help create?

9 Questions not reliant on a station: NCSO a) Suppose an earthquake occurred off the coast of Alaska forming a tsunami that hits Hawaii in 5.5 hours (4000km from Alaska to Hawaii). Knowing that the average wavelength of a tsunami is 215km, what is the wave period? b) Explain why tsunamis are considered shallow water waves. 2. Explain how land and sea breezes form (be sure to include why they only form during certain parts of day) 3. What is the main cause of a La Nina? 4. Why is the term riptide not a proper term? What is the proper name for that phenomena?

10 5. a) Graph the following tidal data on the graph provided, use appropriate titles, labels, etc. Time (hr) Height (ft) Time (hr) Height (ft) Time (hr) Height (ft) 21: : : : : : : : : : : : : : : : : : : : : : : : b) What is the best term to describe this type of tide? c) Which coast (Atlantic, Gulf, Pacific) of the US are you most likely to find this type of tide? d) Why?

11 Station 1: ANSWER KEY a) Which sample is seawater? Depends on event leader, mine was A. 1 pt b) What causes the ph in the seawater to be higher at the surface and lower at the depths? Carbon dioxide (CO2) decreases ph, but at the surface photosynthesis by plankton uses the CO2 increasing the ph at the surface. In the depths, nothing uses the CO2 decreasing the ph. 1pt for talking about the surface and 1 for talking about the depths. c) Why is seawater s ph so different from that of fresh water? Be specific. In seawater, when CO2 dissolves, bicarbonate forms and is used by creatures..forming a buffer system of HCO pt (it s either right or wrong, don t get into semantics) Station 2: a) Identify the objects labeled A, B and C--- 1 point apiece A: fringing reef B: barrier reef C: atoll b) Explain the formation of object B. The island or volcano starts to sink AND the reef around it continues to grow up around it. 1 point c) What two things must be present for an atoll to eventually form? An island (land mass, volcano) AND coral 1 point for each Station 3: a) Label the formations in this painting by Monet. 1 point apiece A Sea Cave B Sea Arch C Sea stacks Go ahead and give credit if the word Sea is not there

12 b) Why don t you see many of these formations off the coast of North Carolina? The rock is too soft (best answer), there are no sea cliffs, waves aren t strong enough, the coast is made of sand Up to 2 points, 1 for each reason. c) In the formation process, which of the three formations comes first? Structure A or sea cave. 1 point Station 4 a) What is the structure in the picture? Hydrothermal vent 1pt a half point for black smoker b) How does it form? A crack in the ocean floor allows water to get below the surface. It gets hot and breaks through another crack as a superheated liquid dissolving lots of minerals as it goes. 1 pt c) Why are they important? Bring minerals to the ocean water (source of sea salt) Source of energy to bottom dwelling creatures Environment for very unusual creatures Up to 2 points, 1 for each answer Station 5 a) Explain the trend for Carbon Dioxide with depth according to the figure. The question was to explain the trend, not describe the trend. 0 points for saying that CO2 increases with depth. CO2 is used by plants and plankton closer to the surface and does not get used by organisms at the depths, in fact it is created by organisms at depths. 1 point for describing surface and 1 pt for describing depth b) At what depth does the oxygen concentration start to increase? Any answer Between 750 and point c) Give an explanation for this observation.

13 Oxygen is used by organisms at the medium depths but in the deep zones there are fewer organisms and the coldwater has some dissolved oxygen in it already. 1 pt for organism reasoning, 1 more for the depths already having oxygen in them. 0 points for saying that plants at the bottom of the ocean make oxygen. Station 6 a) What is the main difference between the surface ocean temperatures in January of 2000 and January 2007? Temperature got warmer 1pt b) What phenomena can be attributed to each of these images? 1 pt apiece Jan 2000: La Nina Jan 2007: El Nino c) What happens to the trade winds when an El Nino forms? The winds stop moving and change direction 1 point for either answer (no more than 1 point for this question) Station 7 a) What title would you give this picture? Something with Turbidity or Sediment in it current) 1 pt (this is a turbidity b) Propose a mechanism for the formation of this phenomena. 1 pt for any of the following no more than one point for this question Propellers or anchors starting an avalanche of sediments Earthquake shifting the sediments Freshwater river sediments moving down a continental slope c) What seafloor feature do the phenomena in this picture help create? Submarine Canyons or just canyons 1pt Total for entire section: 32

14 Questions not reliant on a station: ANSWER KEY 1. a) Suppose an earthquake occurred off the coast of Alaska forming a tsunami that hits Hawaii in 5.5 hours (4000km from Alaska to Hawaii). Knowing that the average wavelength of a tsunami is 215km, what is the wave period? Math should be: 4000 divided by 215 (number of wavelengths) 5.5 divided by that answer (time/wavelength= wave period) I d accept anything from.25 to.3 hr or min. 1pt for setting it up right, 1 point for actual answer b) Explain why tsunamis are considered shallow water waves. Shallow water waves are defined as traveling in water at depths that are less than ½ the wavelength of the wave. Tsunamis have wavelengths so large that half of it is still longer than the ocean is deep. IE, the ocean isn t deep enough to be larger than ½ the wavelength of a tsunami. 1pt definition of shallow wave 1pt connection to the tsunami 2. Explain how land and sea breezes form (be sure to include why they only form during certain parts of day) Sea Breezes land heats up during the day, air warms up and rises sea air then rushes in to replace the air (pressure difference) 1 point Land Breezes in the evening, the sea is warmer than the land (specific heat of water is high so it releases energy more slowly than land), so air rises and land air rushes in to replace it (pressure difference) 1 point Tiebreaker number 1 use of specific heat Remember to only give the points if the times of day (evening, daytime) are mentioned. 3. What is the main cause of a La Nina? The sudden return to normal conditions. 1 point Strong currents, upwelling, and restart of trade winds 1 additional point for any one of the above answers. 4. Why is the term riptide not a proper term? What is the proper name for that phenomena? The phenomena are not tides, they are not caused by the gravitational pull. 1pt Rip current 1 pt

15 5. a) Graph the following tidal data on the graph provided, use appropriate titles, labels, Time (hr) Height (ft) Time (hr) Height (ft) Time (hr) Height (ft) 21: : : : : : : : : : : : : : : : : : : : : : : : a) Tidal Data height (ft) :00 1:00 5:00 9:00 13:00 17:00 21:00 1:00 time (hr) 5:00 9:00 13:00 17:00 Obviously they can t be this neat, but they should have graphed all the information. (1pt) They should have a title (1pt), labels on the axes (1pt), and should have drawn a line (1pt) b) What is the best term to describe this type of tide? Diurnal is the ONLY answer! 1pt c) Which coast (Atlantic, Gulf, Pacific) of the US are you most likely to find this type of tide? Gulf 1 pt d) Why? The Gulf Coast is more protected. 1pt Total for section: 16 Add the two sections together to find the highest scores. It s easiest to write +points and add them than it is to subtract points from a total. Remember that that kids aren t getting these back! If it doesn t sound like the right answer, it isn t don t give them points.