Exam 21: Movement of Elements in Ecosystems

Using what you know about the global carbon cycle, describe two ways that deforesting in tropical forests by burning affects atmospheric carbon dioxide levels.

Chose a logical path for a molecule of water starting and ending in the atmosphere.

During autumn in Ontario, Canada, you are walking by a tree near a deep lake when you see two leaves fall. One leaf drops on the ground near your feet and the other is blown out into the middle of the lake, where it sinks. Assuming that these leaves have identical physical and chemical composition, compare the rate and processes by which the nutrients in the two leaves will be recycled and used again by producers.

In waterlogged conditions, anaerobic metabolism of carbon compounds can cause the production of the greenhouse gas

Current atmospheric carbon dioxide levels are approximately

Define what allochthonous inputs are and the role they play in a stream.

Decomposition is more rapid in _____ forests because of _____.

In dead zones, fish species are at risk when the water shows signs of decreased oxygen levels called

Weathering is important to the input of

Dead zones are formed when rivers that empty into oceans carry excess phosphorus and nitrate runoff. These dead zones are caused by

Stratification of lake waters is due to differences in

What form of nitrogen reacts with water in the air to form nitrates that fall to the ground during precipitation?

How did logging in the Hubbard Brook Experimental Forest affect water and nutrient cycling in the watershed?

What is the largest pool of nitrogen in the global nitrogen cycle?

The energy required for evapotranspiration is provided by

Stratification occurs in all of the following aquatic systems EXCEPT

In aquatic ecosystems, most nutrients regenerate in

The issue associated with the Ogallala Aquifer is

A lake in New York State is fed by a watershed consisting of a single river on its northern end. For many decades this watershed has been forested. However, recently all of the trees on the northern end of the lake were logged. The roots were also removed, and all that remains is bare soil. What effect will this logging have on the watershed's hydrology over the next few decades? How will these effects influence the concentrations of nitrogen and phosphorus in the lake?

Global climate change is primarily caused by increased levels of _____ in the atmosphere.