Study Guide questions

Midterm I

1. What are four disciplines in Marine Biology? Why is marine biology such a unique and important field? (at least 5 reasons)

2. What are the major geomorphological features of the ocean basins? What geological processes gave rise to each of the following features--water in the ocean, ridges, trenches, seamounts? Describe the evidence--in terms of (1) fossil distribution and (2) geological mechanisms-- that supports the theory of continental drift. What is the difference between continental and oceanic crust? Describe the continental shelf in geological terms. What is the difference between passive and active margins?

3. What are the important physical/chemical features of water? Give a few examples of how the chemical and physical properties of water molecules determine the physical environment of marine organisms. Consider the quality and quantity of light, temperature, water density, salinity, oxygen. In what biologically relevant ways does oxygen differ from carbon dioxide in seawater? What are some consequences of the nature of water that can be seen in ways that marine life differs from terrestrial life? Why are primary producers minute suspended cells? Why do many organisms broadcast their gametes, or feed from suspended particles?

4. Why is there less light energy at high atitudes? How does the temperature vary with latitude and among regions of the earth? How about salinity? How does temperature, density, and oxygen change with depth? What processes govern oxygen levels? What is the thermocline and pycnocline, and how do they very with latitude? Why?

5. What role do waves play in vertical circulation? What causes deep circulation of surface water? What factors lead to downwelling at high latitudes? Why is deep ocean water at the equator cold and well-oxygenated? By what processes does this water reach the ocean bottom? Explain the depth of the oxygen minimum zone (use a graph).

6. What is the ultimate cause of trade winds and ocean currents? What directions do major trade winds blow? Explain the Coriolis effect in terms of the earth's circumferance. Why do ocean currents circle clockwise in the Northern Hemisphere, and counterclockwise in the Southern Hemisphere? Describe the paths of the Pacific and Atlantic gyres, both north and south. Describe their specific currents and their temperature characteristics.

7. Describe three types of upwelling. Explain Ekman transport. Which two types of upwelling result from Ekman transport? What is a third type of upwelling? How does Ekman transport affect the center of a gyre?

8. Describe the Great Conveyor. Where are the main sources of water entering the conveyor? Why? Where does this water ultimately reach the surface again? Why might the melting of Greenland ice lead to a cessation of the Conveyor?

9. What two forces generate tides? Why should there be two high and two low tides per day? Describe diurnal, semidiurnal, and mixed semidiurnal tide regimes. What causes spring and neap tides? What moon phases are associated with each? Which habitats of the marine realm are most effected by the tides?

10. What physical habitat conditions would a marine organisms face in each major zone (bathyalbenthic, epipelagic, etc)? What is the difference between nekton and plankton? Between pelagic and benthic organisms? Where do epibenthic versus infaunal animals live?

11. Why do oceanographers study primary productivity? What major factors determine the level of productivity in the oceans? Why are oceans sometimes called biological deserts?

12. What is compensation depth, and how does it vary in clear versus turbid water? What is the critical depth? What are the major limiting nutrients for phytoplankton production? What are the major pools for N nd P? How does the pool and sink for N and P differ? What is the fate for nutrients tied up in organisms?

13. What factors are responsible for global trends in productivity? What factors are responsible for seasonal variation in productivity in the temperate zone? Consider at least these factors: light, nutrients, and biotic interactions. Describe the bottom-up and top-down hypotheses for seasonal patterns of phytoplankton abundance in termperate zones. Do you think tropical ocean productivity is driven by top-down or bottom-up processes? How about polar oceans?

14. Why are shelf and upwelling areas high in productivity? Why is shelf productivity highest on the "inner shelf"? Coastal Peru has high productivity because _______________. Name a specific area of the ocean that experiences the same conditions. Name specific ocean regions, other than Peru, that illustrate high productivity created by the three types of upwelling.

15. What are HNLC areas, and where are they? Summarize two hypotheses for HNLC areas. What evidence suggests that they are caused by limiting minor nutrient? What are the possible benefits and costs of fertilizing the oceans with iron?

16. What are possible causes of excess nutrients? What are some consequences of excess nutrients in marine environments? What are potential consequences of excessive levels of primary productivity? Describe the process of eutrophication.

17. What consequences does El Nino have for primary productivity? What impact will climate change and global warming have on ocean productivity and zooplankton abundance? How will these impacts affect higher levels of the food chain? How do you think current trends in global climate will alter oceans, if at all?

Last Update 5 February 2007