Exam 57: Ecosystems

Approximately 60 percent of Earth's ecosystem services are currently being degraded or are being used unsustainably.One ecosystem service that is probably not degrading, at least at present, is

Refer to the figure. Briefly describe and explain the latitudinal differences in NPP values between land and ocean, as shown on the two maps.

A major difference between phosphorus cycling and nitrogen cycling is that unlike nitrogen, phosphorus

An ecologist might define a soil ecosystem as all the organisms and interactions involved in transferring nitrogen through the system.He might also define a soil ecosystem as the flow of energy through all the organisms in 2 square meters of soil.Why would both definitions be correct?

Within a food web, energy flows through a series of trophic levels.Rabbits are eaten by jackals, one of which is eaten by a lion.This flow of energy is an example of _______ production.

Compare the nitrogen and phosphorus cycles with respect to their major pools and fluxes and their flow through organisms.

The atmosphere contains a relatively low concentration of carbon, mostly in the form of CO₂.Why is this small amount considered important in the carbon cycle?

In the open ocean, some regions have excess nitrogen.The NPP in these areas is usually limited by _______.

Tropical terrestrial ecosystems, such as rainforests, have very high NPP.NPP declines as you move northward through temperate deciduous forests and then boreal forests.In the open ocean, NPP shows much less variation with location.These differences reflect varying land and ocean patterns based on _______.

A shallow lake near an urban area is important for fishing and swimming and contains a large biodiversity of organisms.But recent filling of adjacent wetlands for agriculture has decreased the quality of the lake water.This is an example of an ecosystem service _______.

Plants cannot use nitrogen directly from the atmosphere; they depend on nitrogen fixation by bacteria, many of which live in nodules on plant roots.These bacteria fix nitrogen in the form of _______.

Explain how humans are affecting NPP by changing nutrient concentrations and atmospheric CO₂ concentrations.Use examples that show the interaction of CO₂ and other nutrients.

Moving carbon, nitrogen, and other nutrients around the planet, as opposed to moving them locally, is done primarily by which type(s) of processes?

Two tropical forest regions receive extremely high rainfall (more than 400 cm/yr).The NPP of forest A is much higher than the NPP of forest B.Which factor is likely most associated with the difference in NPP?

Refer to the figure. In the top-down situation shown, what is the relationship between top carnivores (secondary consumers) and the abundance or biomass of primary producers in a food web?

In 2005, bleaching of coral reefs in the Caribbean killed half of the reefs.The National Ocean Service measured their temperature stress at 20 times higher than that of the previous 20 years combined.Also, many fewer coral larvae are settling in areas with higher-than-normal ocean acidity.From this information, what can be inferred about the effects on coral reefs of increased atmospheric CO₂?

Algal beds contribute very little to Earth's total net primary production because they are limited by

Offshore oil drilling in the United States provides oil that is refined to make many products to provide energy for human civilization.Making this provisioning service possible requires many changes to natural ecosystems.Along the Gulf Coast, thousands of canals, pipelines, and drilling rigs are installed, shipping lanes are dredged, and cypress swamps and other wetlands are destroyed.Which is one ecosystem service lost in trade-off as a result of these changes?

Which is the correct order of forest types, from lowest to highest total NPP.

Carbon is currently being released into the atmosphere by fossil-fuel burning.Why does this release of carbon cause global warming, when carbon released by organism respiration does not?