ConcepTest: Drivers of Ocean Salinity Variations

Jenny Fisher, University of Wollongong Australia, jennyf AT uow DOT edu DOT au
Questions used in MARE200 Introduction to Oceanography (2nd year undergraduate).

Initial Publication Date: June 9, 2015

Question:

Imagine ocean circulation stopped suddenly, with half of the world's salts in the northern hemisphere and half in the southern hemisphere. Assuming no net difference between evaporation and precipitation (E-P=0) in both hemispheres, where would salinity be highest?

A. Northern Hemisphere
B. Southern Hemisphere
C. Equal in both hemispheres

Student Responses:

If you would like to help acquire more Before and After statistics for this example, please contact the authors.

No data yet. The correct response is A. The Northern Hemisphere has more land and less ocean area. With no exchange between the hemispheres to redistribute salts and no net water inputs to either basin, the volume of water is the key determinant of salinity variations.

References and Notes:

The use of ConcepTests and Peer Instruction is discussed in detail on the ConcepTest page.

McConnell, D.A., Steer, D.N. and Owens, K.A., 2003, Assessment and Active Learning Strategies for Introductory Geology Courses, Journal of Geoscience Education, 51(2), 205-216.

McConnell, D.A., Steer et al., 2006, Using Conceptests to Assess and Improve Student Conceptual Understanding in Introductory Courses, Journal of Geoscience Education, (54(1), 61-68.