The Massachusetts Water Resources Authority (MWRA) claims that the $3.8 Billion dollar Boston Harbor Cleanup has been a great success.    a.)…

The Massachusetts Water Resources Authority (MWRA) claims that the $3.8 Billion dollar Boston Harbor Cleanup has been a great success. 


a.) Please present evidence (data for a specific parameter) that water quality is better in Boston Harbor than it was 20 years ago? Explain why this data supports your claim that water quality is better now. (5 points)


b.) What can you do to make the water quality (with respect to this parameter) even better?  Extend the data given above into the future. How clean can Boston Harbor water become (with respect to your measurement)? Please be specific.

(5 points)



2.) Water Cycle 


a.) If the Quabbin Reservoir Watershed is 100 km2, the average precipitation in New England is 130 cm/year, and the volume of the Reservoir is 1.5 x 1012 liters, what is the residence time of water in the Reservoir with respect to rain?    Please show your calculation and explain all your assumptions. (5 points)


b.) Name 5 contaminants that could make Quabbin water undrinkable. Why is water containing these contaminants undrinkable (i.e. how does the contaminant affect you)? How can we remove each of these contaminants (there are possibly different methods for each contaminant) to make the water drinkable?  Please be specific.  (5 points)




3.) Ecosystems


a.) Design an ecosystem in a glass container 12” x 12” x 12”.  (Just describe it and draw it, you don’t have to build it.  No shrimp please!) This is a closed system…no gas, liquid, or solid can enter or leave.  Light can enter and heat can be transferred through the glass.  You can add anything you want before you seal it.  Describe what biotic (living) and abiotic (non-living) components are needed to make this a sustainable ecosystem.  What does it mean to be sustainable?  (7 points)


b.) Describe the flow of a single carbon atom in the ecosystem you have created.  How long might the carbon atom reside in each of 5 reservoirs in your cycle? (3 points)



4.) Photosynthesis


Saltmarsh cordgrass grows in salt marshes.




a.) Describe three adaptations that salt marsh cordgrass has to survive in an intertidal estuary. (6 points)


b.) What limits its growth in the spring? In the fall? Explain your reasoning.  (4 points)





5.) Carbon Cycling


a.) Explain the variations of carbon dioxide over time. (6 points)


b.) Where does the excess atmospheric carbon dioxide go (6.0 gigatons of C per year enter the atmosphere from the burning of fossil fuels, yet atmospheric concentrations only increase by 3.2 gigatons of C per year)? (4 points)


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