Ecology Ch. 19

Examples of carbon sinks, locations where carbon is relatively unavailable for long periods of time, include: fossil fuels, carbonate rock, soil

Atmospheric forms of carbon include carbon dioxide and methane gas (CH4)

The concentration of atmospheric carbon has increased since the onset of the industrial revolution

In a study done, nitrate export in streams draining watersheds in Baltimore County, Maryland, it was shown that land use affects the average nitrogen concentration. Rank the average nitrogen concentrations in the streams from lowest to highest. Forested area; urban area; suburban area; agricultural area

A friend tells a woman that some of the carbon in her body could have once been found in a dinosaur. The woman should: agree because elements cycle through the environment

Organic molecules such as hemoglobin, contain not only carbon, hydrogen, and oxygen, but also nitrogen. This element is also crucial to primary production and is relatively scarce.

Nitrogen in the atmosphere is: the main pool of nitrogen in the environment; converted to other forms by algae; converted to other forms by cyanobacteria

When nitrogen is converted from an organic form to an inorganic form, the process is called mineralization. This process mainly takes place during the breakdown of organic matter and is called decomposition

The main sources of phosphorus in the ecosystem are: mineral deposits such as rocks; marine sediments

When a specific nutrient is absorbed faster than it is released into the environment, this type of nutrient pool is called a nutrient sink

Plants are assisted in their uptake of phosphorus from the soil due to their interaction with mutualistic mycorrhizal fungi

Phosphorus (or phosphate) can enter aquatic environments: as runoff from land following the melting of snow; as runoff from land following rain storms; as runoff from fertilized farm fields

The burning of fossil fuels has become a major source of atmospheric carbon dioxide

Which of the following molecules in living organisms do NOT contain phosphorus?

Ribose sugar

Does contain: ATP; RNA; phospholipids; DNA

Examples of human (anthropogenic) sources of nitrogen enrichment include: runoff from agricultural land into waterways; burning of fossil fuels

Increased population densities are associated with: increased nitrogen enrichment of river ecosystems

In a nutrient cycle, chemicals are stored in nutrient pools or compartments

Concerning the movement of phosphorus through the environment: phosphorus can move from rivers into oceans

Sedimentary rocks rich in phosphorus are mined for fertilizer

Which of the following are true?

Plants growing in low-nutrient ecosystems allocate more resources to root growth compared to shoot growth

Plants growing in high-nutrient ecosystems grow at a faster rate than those in low-nutrient ecosystems

Nutrient enrichment of an aquatic ecosystem that can be due to human activities is called eutrophication. It can result in water quality problems

Carbon dioxide is removed from the atmosphere by the process of photosynthesis

Animals gain phosphorus, in the form of phosphate, by: ingesting plants that contain phosphate; ingesting other animals that contain phosphorus compounds

Decomposition rate is mainly affected by moisture levels, the chemical composition of litter and the environment, and temperature

Which of the following is correct concerning the movement of carbon between organisms and the environment? Respiration returns carbon to the atmosphere in the form of carbon dioxide

An example of a nutrient source would be: burning of fossil fuels that add carbon dioxide to the atmosphere

Phosphorus is essential to living organisms. For example, phosphorus is the main component of cell membranes when it is combined with lipids to form phospholipids

Which of the following molecules found in living organisms do NOT contain nitrogen? Cellulose (fiber)

Does contain: proteins, such as hemoglobin; chlorophyll; nucleic acids, such as DNA

Which of the following molecules found in living things always contain carbon? Lipids; carbohydrates; proteins

In major river ecosystems, such as the Mississippi, Thames, and the Amazon, the single variable that appeared to explain most of the variation in nitrate concentration and export was human population density

Burning of fossil fuels has increased the concentration of CO2 in the atmosphere since the industrial revolution, despite oceans acting as carbon sink

The conversion of nutrients such as phosphorus from an organic form to an inorganic form is called mineralization

Research done by Takyu, Aiba, and Kitayama indicates that higher concentrations of phosphate in the soil are associated with: higher rates of decomposition; increased rates of leaf litter fall

Areas that may have high levels of CO2 uptake (vs. output) that are reducing the predicted effects of increased burning of fossil fuels are referred to as being the “missing carbon sinks”

In a river or stream where nutrient spiraling is occurring, nutrients may be used many times (cycled) before leaving a stream system, when: the spiraling length is short

In the study done by Meyer and Likens on the movement of phosphorus in the Bear Brook ecosystem, inputs to the ecosystem included: precipitation; seeps

One way humans overcome nitrogen limitation to plant growth is to rotate crops capable of nitrogen fixation with crops that have high nitrogen needs. These crops add ammonium to the soil

Work done by McNaughton, Ruess, and Seagle, indicate that large grazing animals, such as bison: speed up nutrient cycling in an ecosystem

Nutrient cycling can be affected by animals transporting nutrients from one ecosystem to another. An example of this are the Pacific salmon that spend most of their lives at sea. However, after spawning in streams and lakes, the salmon die and their carcasses are utilized by other organisms

In suburban areas, one contributor to increased nitrate input to stream ecosystems can be the presence of septic systems

Because water currents move nutrients downstream, Webster coined the term nutrient spiraling to describe stream nutrient dynamics

Which of the following could explain the high level of nitrogen retention in suburban watershed areas? Riparian areas; actively growing lawns

Decomposition rates in tropical environments are lower than in temperate ecosystems. FALSE

Using the graph, results from research on decomposition rates show: plants with higher toughness: nitrogen rations lost less mass

Nitrogen can enter the nutrient cycle through fixation by living organisms or through the energy and pressure generated by lightning

As shown in the Gallardo and Merino study, elevated moisture levels have a positive effect on leaf decomposition

Using the graph as an aid, during years of high streamflow, Bear Brook: exports of phosphorus were greater than inputs

One form of deforestation, which involved removing all trees from an area is called clear-cutting. When this occurs, nitrate losses from the environment increase

Pocket gophers may increase plant diversity by increasing the heterogeneity of nutrient availability in the soil

Denitrification: is energy producing and is carried out by bacteria

Using the graph, the results of the Gallardo and Merino experiments showed: higher levels of precipitation are associated with higher levels of leaf decomposition

Animals may gain nitrates from ingestion of plants. When these animals die, the animals decompose. This decomposition leads to the production of ammonium. Eventually, bacteria convert ammonium to nitrate in the process called: nitrification

Because plant growth is dependent on nitrogen, and fixed nitrogen is relatively low in abundance, humans add fertilizer to the soil to increase crop production

In the Serengeti ecosystem it was shown by McNaughton, Ruess, and Seagle that: grazing by large herbivores resulted in biomass turnover in less than one year

In the nitrogen cycle, nitrogen is returned to the atmosphere through the process of: denitrification

Using the graph, results from research on decomposition rates forests show: the toughness of plant leaves is inversely related to decomposition rates

Because higher evapotranspiration rates increase the rate of decomposition, decomposition in temperate ecosystem is usually lower than in tropical ecosystems

In the experiment performed by Likens and Bormann on the effects of deforestation on nutrient cycling, inputs to the stream ecosystems include weathering of granite bedrock and precipitation

Fungi and bacteria release nitrogen as ammonium through the process called: ammonification

The effects of leaf litter chemistry on decomposition in Mediterranean woodland ecosystems were studied by Gallardo and Merino

In a study performed by Gallardo and Merino to investigate the effects of litter chemistry on decomposition, the mesh bags contained holes 1mm large. This allowed aerobic microbial activity and small soil invertebrates to aid in decomposition

Using the graph as an aid, during years of low streamflow, Bear Brook: stores phosphorus

In a stream ecosystem, nutrient retentiveness is inversely related to spiraling length, meaning that as one value increases, the other value decreases

Suberkropp and Chauvet showed that as nitrate levels in a stream increased, decomposition of yellow poplar leaves: increased

The term nutrient spiraling was coined by the scientist named Jack Webster

Bison tend to feed on grasses that are near prairie dog mounds because the grasses are higher in nitrogen content

Research results (Mellillo and colleagues) from two temperate forests suggest that higher decomposition rates of leaf litter in a North Carolina forest compared to a forest compared to a forest in New Hampshire may be due to greater availability of the nutrient nitrogen in the soil

Many detritivores reingest nutrients such as nitrogen by eating their feces

Work done by Rosemond and colleagues suggest that leaf decomposition rate increases in the presence of increased phosphorus concentration

In the Hawaiian ecosystem, it was shown that the introduced Myrica tree altered the nitrogen content in the soil

In a study done by Meyer and Likes, it was shown that in the Bear Brook ecosystem, there were annual pulses of phosphorus import and export. However, most phosphorus export was irregular because it was associated with: flooding caused by storms

Gessner and Chauvet determined that higher lignin content in plant materials inhibits colonization by fungi that are mainly responsible for decomposition of leaves in stream habitats

The results of experiments done by Suberkropp and Chauvet on the effects of nitrate on decomposition in freshwater had results that were consistent with the study done by Melillo on how soil nitrogen content affects decomposition

Gallardo and Merino were the scientist who studied how chemical differences in leaves, such as lignin concentration, affect decomposition in woodland ecosystems. TRUE

The scientist who described how nutrients in streams are subject to downstream transport, causing cycling to NOT occur in one place is named: Jack Webster

In stream ecosystems, spiraling lengths that are short are associated with high nutrient retentiveness

Work done by Whicker and Detling found that: prairie dog grazing results in young grass tissues high in nitrogen content

In the study performed by Grimm: the 10% of nitrogen tied up in macroinvertebrate biomass lowers V in the equation for spiral length

Based on research done in temperate forests by Melillo and colleagues, plants with lower lignin: nitrogen rations decomposed at a higher rate

In the Hawaiian ecosystem, the Myrica tree was introduced. Compared to the native trees in the Hawaii Volcanoes National Park, it: has leaves that decompose at a higher rate

Results of a study done on yellow poplar leaf decomposition in a stream habitat by Suberkropp and Chauvet indicated that: higher nitrate concentration resulted in higher decomposition rates

At high phosphorus levels: leaf decomposition rates level off at high values

Grimm’s study showed that macroinvertebrates appear to affect the spiraling of nitrogen in aquatic habitats by: reingestion of nutrients by the macroinvertebrates resulting in increased primary production