BI210 Chemistry Ch 25 Review: Methane & Carbon Cycle

Between 1880 and 2012, the average annual global surface temperature

increased 0.8°C.

Before the Industrial Revolution, the flux of carbon from the terrestrial to the atmospheric pools _______ the flux in the opposite direction. Today, the flux of carbon from the terrestrial to atmospheric pools _______ the flux in the opposite direction.

was about equal to; exceeds

Refer to the figure, showing the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years. The current concentration of carbon dioxide is 404 ppm (not shown on the figure). Use the data in the figure to determine the highest carbon dioxide concentration levels that occurred over the past 400,000 years. At that point, the concentration of carbon dioxide was about _______% of the current concentration.

70‒75

Which statement about the nitrogen cycle is false?

The nitrogen cycle is not linked to the carbon cycle.

Increasing levels of carbon dioxide in the oceans make them _______ acidic. This change affects the ability of marine organisms to form protective shells made up of _______ carbonate.

more; calcium

Which statement about CFCs is false?

They are largely inert in the stratosphere; their negative effect on ozone occurs because they react with other chemicals in the trophosphere to produce reactive chlorine molecules that destroy ozone.

DeLucia and colleagues have shown that increasing carbon dioxide has led to increased NPP in a pine forest. If this result can be generalized, it suggests that forests could be a _______ of anthropogenic carbon and thus tend to _______ the greenhouse effect.

sink; offset

Which statement about deforestation is false?

Currently deforestation accounts for a negligible amount (less than 2%) of the anthropogenic release of carbon into the atmosphere.

Which event would lead to enhanced atmospheric warming?

Decreased anthropogenic emissions of SO2

Which statement about ozone in the lower atmosphere is false?

It is not produced naturally and results only from anthropogenic activity.

Which statement about methane and global warming is false?

Methane emissions are caused only by anthropogenic factors.

A reduction in aerosols in the atmosphere would tend to _______ temperatures, because aerosols _______ sunlight.

increase; reflect

Which statement best describes our current understanding of the relationship between CO2 levels and photosynthetic activity?

Increases in photosynthesis rates due to increases in CO2 levels are likely to be short-lived for some herbaceous plants, but may be more sustained for forest trees.

Refer to the figure, showing the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years. Ten thousand years ago, the concentration of carbon dioxide was about _______ times that of methane.

500

Refer to the graph, showing the mean annual global temperature anomalies between 1880 and 2005. Aside from the recent (1981-2000) rise, over which 20-year period did temperatures rise the most?

1921 - 1940

Which graph, based on the studies of grassland communities by Stevens, best describes the relationship of species diversity to varying levels of deposition of inorganic nitrogen?

Graph C

Which statement about the global sulfur cycle is false?

Sulfur is often a limiting factor for organismal growth.

Which statement about climate is false?

Climatic variation can occur only on very long time scales.

Refer to the figure of the global carbon cycle. (Note: Boxes represent major pools of C, measured in petagrams [1 Pg = 1015g]. Arrows represent major fluxes of C, measured in Pg per year; anthropogenic fluxes are shown in orange.)In the absence of human activity, the net flux would be _______ Pg.

-4

Which organism would most likely encounter the greatest difficulty in responding to climate change?

A long-lived tree

The largest pool of carbon can be found in

sediments and rocks.

According to the studies of Nemani and colleagues, global NPP _______ during the study period (1982-1999), with the largest increase documented in the _______.

increased; tropics

The warming of Earth in recent decades has been most pronounced in

the mid-to-high latitudes of the Northern Hemisphere.

Which statement about the global phosphorus cycle is true?

Because of the relatively high metabolic demand for phosphorus in the fixation of nitrogen gas, the rate of the nitrogen cycle is influenced by the availability of phosphorus.

Select the greenhouse gas that fits the following description: Its concentration in the atmosphere has increased substantially over the last century; and while its total contribution to the greenhouse effect is only about 30% that of CO2, its contribution on a per molecule basis is greater that of CO2.

Methane

Which statement regarding the oceanic pool of carbon is false?

The oceanic pool is the most stable of the major pools.

The figure shows the pH of precipitation in the United States in 1994 (top) and 2004 (bottom). The acidity of precipitation during both time periods was most extreme in the _______ part of the country, and the acidity of precipitation in this area _______ between 1994 and 2004.

eastern; decreased

Refer to the figure of the global carbon cycle. (Note: Boxes represent major pools of C, measured in petagrams [1 Pg = 1015g]. Arrows represent major fluxes of C, measured in Pg per year; anthropogenic fluxes are shown in orange.) What is the net flux of carbon to the atmosphere?

6.4 Pg

Which of the following is not one of the currently documented ecological responses to climate change?

Migratory birds in England and North America have been arriving at nest sites later in the season.

In areas such as Vermont that have a seasonal snowpack, which of the following would likely be the most acidic?

The first meltwater of spring

Why is there a net flow of carbon from the atmosphere to the oceans?

The lower concentration of carbon dioxide in the oceans compared to the atmosphere leads to carbon dioxide diffusing into the oceans.