Exam 53: Ecosystems and Global Ecology

Figure 53.7 -Considering the global water cycle depicted in the figure above, where does one find the largest amount of water changing phases?

Figure 53.3 -Which category in the figure above makes available the highest productivity per square meter?

What do researchers typically focus on when they study a particular biogeochemical cycle?

Figure 53.3 -Which habitat type in the figure above covers the largest area on Earth?

How are the components in the figure above linked by the flow of energy?

When primary producers expend energy to build new tissue, this is

Figure 53.4 -After looking at the experiment in the figure above, what can be said about productivity in marine ecosystems?

What is the leading hypothesis as to why terrestrial productivity is higher in equatorial climates?

At the Hubbard Brook Experimental Forest in New Hampshire, how did large amounts of energy leave the decomposer food web?

Why are changes in the global carbon cycle important? I. Burning reduces available carbon for primary producers and, therefore, primary consumers. II. Deforestation and suburbanization reduce an area's net primary productivity. III. Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate. IV. By using fossil fuels, we are destroying a nonrenewable resource.

Figure 53.3 -In the figure above, how is net primary productivity represented?

Figure 53.8 -Considering the global nitrogen cycle, how are humans altering this cycle?

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be true?

Figure 53.5 -After looking at the figure above, what can be said about productivity in this ecosystem?

You own 300 acres of patchy temperate forest. Which one of the following actions would increase the net primary productivity of the area the most?

Use the following information when answering the corresponding questions). Abstract: Increased radiative forcing is an inevitable part of global climate change, yet little is known of its potential effects on the energ in natural ecosystems. To simulate the conditions of global warming, we exposed peat monoliths depth, 0.6 cm; surface area, from a bog and fen in northern Minnesota, USA, to three infrared IR) loading ambient, +45, and +90 W m^{- 2}) and three water table - 16, - 20, and - 29 cm in bog and - 1, - 10 and - 18 cm in fen) treatments, each replicated in three mesocosm plots. Net radiation Rn) and soil energy fluxes at the top, bottom, and sides of the mesocosms were measured in 1999, five years after the treatments had begun. Soil heat flux G) increased proportionately with IR loading, comprising about 3%- 8% of Rn. In the fen, the effect of IR loading on G was modulated by water table depth, whereas in the bog, it was not. Energy dissipation from the mesocosms occurred mainly via vertical exchange with air, as well as the deeper soil layers through the bottom of the mesocosms, whereas lateral fluxes were 10- to 20- fold smaller and independent of IR loading and water table depth. The exchange with deeper soil layers was sensitive to water table depth, in contrast to G, which responded primarily to IR loading. The qualitative responses in the bog and fen were similar, but the fen displayed wider seasonal variations and greater extremes in soil energy fluxes. The differences of G in the bog and fen are attributed to differences in the reflectance in the long waveband as a function of vegetation type, whereas the differences in soil heat storage may also depend on different soil properties and different water table depth at comparable treatments. These data suggest that the ecosystem- dependent controls over soil energy fluxes may provide an important constraint on biotic response to climate change. -The Noormets et al. study 2004) shows that there was an ecosystem- specific control over soil energy fluxes, and this constrained the biotic response to climate change. How do you think radiative heat would affect the water table in a wetland versus a temperate forest?

How much nitrogen is fixed from human processes?

Which of the following most often controls the rate of nutrient cycling in ecosystems?

Figure 53.6 -After looking at the experiment in the figure above, what can be said about nutrient export in ecosystems?

Which of the following human activities is impacting the water cycle the least?