Exam 57: Ecosystems

What is the current world situation with respect to atmospheric CO₂ levels? How does ocean absorption of CO₂ affect atmospheric CO₂ levels, and what are its likely effects on ocean life?

Research ecologists often specialize in one level of ecology.Which question would most likely be studied by a Yellowstone National Park ecologist specializing in biogeochemical cycles in ecosystems?

Refer to the graphs. The highest NPP would occur under which combination of temperature and precipitation?

A city council is considering a proposal to change the zoning on a city-owned wilderness park so a corporation can build a new fertilizer factory.The park is a favorite spot for hikers, photographers, and birdwatchers.The stream running through it provides clean water to animals throughout the region.The corporation argues that any recreational loss will be offset by the jobs the factory will bring to the area.They say that people can have wilderness experiences elsewhere.Using the concept of ecosystem services, develop an argument for keeping the park.

In the diagram, boxes represent pools, and arrows represent fluxes. Based on the diagram, most of the world's carbon is stored in which pools?

Refer to the graph. Based on the graph, which is the best comparison that can be made between oceanic and terrestrial ecosystems?

Refer to the figure. Based on the diagram, the process most responsible for returning nitrogen to the atmosphere as a gas is

If a practice allows humans to benefit from an ecosystem or its resources without compromising the integrity of other ecosystems, that practice is said to be _______.

Which of these land ecosystems would be expected to have the highest total net primary productivity?

The oxygen produced by photosynthesis is considered an ecosystem service because

Refer to the graph. In the FACE experiment in a North Carolina forest, the amount of tree growth (change in carbon biomass per square meter) was measured under conditions of ambient CO₂ (270 ppm in 2000, when measurements were done) and elevated CO₂ (550 ppm).Half of both the ambient and elevated plots were given additional nitrogen (fertilized); the other half were not (unfertilized).According to the results shown, what can be concluded about the effectiveness of elevated CO₂ on increasing rate of tree growth?

Food webs can be regulated by mostly top-down or mostly bottom-up control.Which is an example of mostly bottom-up control?

Refer to the figure. According to the figure, how does the amount of nitrogen entering the atmosphere from human activities compare with the amount entering from land-based natural sources? (All values are in units of 10¹² grams.)

Considering food webs in the Konza Prairie of Kansas, an ecologist predicted that in food webs with odd numbers of levels (three or five, for example), grazers would be limited by predators, and plants would thrive (that is, there would be high levels of primary production).Conversely, for food webs with even numbers (two or four, for example), he predicted that grazers would be limited by food, and the landscape would have less plant abundance.If this is correct, the highest NPP would likely be found in a food web having how many levels?

Global climate has a strong effect on NPP, which shows a constant increase as _______ increases.

As people burn fossil fuels, CO₂ is released into the atmosphere, and almost half of this excess CO₂ dissolves into the oceans, where it forms acidic compounds, lowering the ocean pH.In ecological terms, this process is an example of

Coal burning produces 44 percent of the energy used in the United States and is the single largest producer of air pollution.Among other pollutants, coal-burning power plants are the major source of sulfur dioxide (SO₂).What is a major consequence of this coal burning?

A bacterial species lives deep in the ocean, where chemicals including hydrogen sulfide and methane seep out of superheated magma.The bacteria obtain their energy by breaking down these chemicals and building organic chemicals from them.They are carrying out which biological process?

The major factor causing carbon dioxide increase in the atmosphere is that

In peatland ecosystems, organic material builds up in the soils, which become a carbon sink.In Southeast Asia, peatlands are often drained and used as oil palm plantations.This releases their carbon back into the atmosphere, which contributes to climate change.In this scenario, what ecosystem service is lost as a result of human changes to the ecosystem?