Chapter 55: Ecosystem and Restoration Ecology

In aquatic (marine and freshwater) ecosystems, both ______ and _______ are important in controlling primary production.

Light; nutrients

In aquatic ecosystems, ________ and ___________ limit primary production. In terrestrial ecosystems, climatic factors such as ____________ and _________ affect primary production at large scales, but soil nutrient is often the limiting factor.

Light; nutrients; temperature; moisture

As a chemical element moves through a biogeochemical cycle, it moves between "bio" and "geo." The "Bio" in biogeochemical refers to biotic reservoirs, or _________.

Living organisms

Local conditions such as heavy rainfall or the removal of plants may limit the amount of nitrogen, phosphorus, or calcium available to a particular ecosystem, but the amount of carbon available to the system is seldom a problem. Why?

Many nutrients come from the soil, but carbon comes from the air.

Which of these is NOT an organic molecule? Carbohydrates Minerals Proteins Glucose Lipids

Minerals

WHAT IF? Why is nutrient availability in a tropical rain forest particularly vulnerable to logging?

Most of the nutrients in a tropical rain forest are contained in the trees, so removing the trees by logging rapidly depletes nutrients from the ecosystem. The nutrients that remain in the soil are quickly carried away into streams and groundwater by the abundant precipiation.

The direct product of nitrogen fixation is ________.

NH3

What is the chemical formula for a nitrite?

NO2-

What is the chemical formula for a nitrate?

NO3-

WHAT IF? Suppose a forest was heavily burned by a wildfire. Predict how NEP of this forest would change overtime.

Net Ecosystem production (NEP) is a measure of the total biomass accumulation during that time. Therefore, the NEP of this forest would decrease, as in the fire the forest trees are destroyed.

A measure of production that is calculated by subtracting autotrophic respiration from all primary production in an ecosystem is called _______.

Net primary production

Using the analogy of a paycheck you can think of ____________________ as the take-home pay, which equals _______________________, the gross pay, minus respirection (Ra), the taxes.

Net primary production (NPP); Gross primary production (GPP)

WHAT IF? Predict how the results would change if water samples were drawn from areas where new duck farms had greatly increased the amount of polluation in the water. Explain.

New duck farms would add extra nitrogen and phosphorus to the water samples used in the experiment. We would expect that the extra phosphorous from these new duck farms would not alter the results (because in the original experiment, phosphorous levels were already so high that adding phosphorus did not increase phytoplankton growth.) However, the new duck farms might increase nitrogen levels to the point where adding extra nitrogen in an experiment would not increase phytoplankton density.

Denitrifying bacteria convert _____ to ______.

Nitrates to nitrogen gas

_____________ is the conversion of organic nitrogen-containing compounds to nitrates and nitrates.

Nitrification

Bacteria are especially important in making __________ available to plants.

Nitrogen

_____________ removes nitrogen from the atmosphere.

Nitrogen Fixation

Nitrite is converted to nitrate (NO3-) by nitrifying bacteria is a key process of the _____________.

Nitrogen cycle

As in aquatic systems, _________ and __________ are the nutrients that most commonly limit terrestrial production.

Nitrogen; phosphorous

Retaining _______________ in an ecosystem helps to maintain the productivity of the system, as well as to avoid algal blooms and other problems causes by excess nutrient runoff.

Nutrients

The biggest difference between the flower of energy and the flow of chemical nutrients in an ecosystem is that _______.

Nutrients are recycled, but energy is not

Why is only a small portion of the solar energy that strikes the Earth's atmosphere stored by primary producers?

Only a fraction of solar radiation strikes plants or algae, only a portion of that fraction is of wavelengths suitable for photosynthesis, and much energy is lost as a result of reflection or heating of plant tissue.

The Earth is an _________ system with respect to energy and a ___________ system with respect to chemical elements.

Open; closed

In ecosystems, organisms at the highest trophic levels usually contain less collective biomass than the organisms at lower trophic levels because _______________.

Organisms are inefficientt at converting the energy they consume into biomass

Carbon moves from an abiotic reservoice to living organisms during the process of ______.

Photosynthesis

The carbon cycle primarily reflects the reciprocal processes of ____________ and _________.

Photosynthesis; cellular respiration

Both energy and chemicals are transformed in ecosystems through _________ and ________.

Photosynthesis; feeding relationships

Human actions are causing climate change, thereby affecting Earth's ecosystems - few of which have been affected as greatly as those in the Arctic. Hypothesize how climate change might cause evolution in arctic tundra populations. Explain.

Populations evolve as organisms interact with each other and with the physical and chemical conditions of their environment. As a result, any human action that alters the environment has the potential to cause evolutionary change. In particular, since climate change has greatly affected arctic ecosystems, we would expect that climate change will cause evolution in arctic tundra populations.

Over oceans, evaporation exceeds _____________. Runoffs and groundwater flows to the oceans that are responsible for balancing the water lost by ____________.

Precipitation; evaporation

When you eat an apple you are a _______________.

Primary consumer

Poison ivy is a _____________.

Primary producer

____________________ sets the spending limit for the global energy budget. ________________ is the total energy assimilated by an ecosystem in a given period. _______________, the energy accumulated in autotroph biomass, equals gross primary production minus the energy used by the primary producers for respiration. _________ is the total biomass accumulation of an ecosystem, defined as the difference between gross primary production and total ecosystem respiration.

Primary production; Gross primary production; Net primary production; Net ecosystem production

The relationship between biomass and primary productivity is that ____________.

Primary productivity is the rate at which biomass is produced

In general, the biomass in an ecosystem will be greatest at the trophic level comprising ___________.

Producers

The amount of energy available to each trophic level is determined by the net primary production and the ____________, the efficiency in which food energy is converted to biomass at each link in the food chain.

Production efficiency

The percentage of energy stored in assimilated food that is not used for respiration is the _________.

Production efficiency

Nitrogen fixation by ______________ makes nitrogen available to plants.

Prokaryotes

Why does deforestation of a watershed increase the concentration of nitrates in streams draining the watershed?

Removal of the trees stops nitrogen uptake from the soil, allowing nitrate to accumulate there. The nitrate is washed away by precipiation and enters the streams.

In contrast to bioremediation, which is a strategy for __________, biological augmentation ___________ a degraded ecosystem.

Removing harmful substances; uses organisms to add essential materials to

Cycle diagrams include a representation of the _______________ in which the chemical element is found. A ____________ can consist of either organic or inorganic materials, and those materials may be either available for direct use by organisms or unavailable.

Reservoir(s)

In a biogeochemcial cycle, a chemical element spends time in different places, called ______.

Reservoirs

By which process is carbon dioxide released from plants back to the atmosphere?

Respiration

The long-term objective of _____________is to return an ecosystem as closely as possible to its predistrubance state.

Restoration

____________ is the science of facilitating the return of a degraded ecosystem to a more natural condition.

Restoration ecology

Why would runners have a lower production efficiency when running a long-distance race than when they are sedentary?

Runners use much more energy in respiration when they are running than when they are sedentary, reducing their production efficiency.

Consider this segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and spiders; owls eat shrews. The shrew occupies the trophic level (s) of _________.

Second and tertiary consumers

What is the amount of chemical energy in a consumer's food that is converted to its own new biomass over a period of time called?

Secondary production

What is the main abiotic factor reservoir for elements, such as calcium and phosphorous, involved in local biogeochemcial cycles?

Soil

Water moves in a global cycle drive by ____________.

Solar energy

What are the major factors that control primary production in terrestrial ecosystems?

Temperature and moisture

At regional and global scales, ____________ and ___________ are the main factors controlling primary production in terrestrial ecosystems.

Temperature; moisture

WHAT IF? In what way is the Kissimmee River project more complete ecological restoration than the Maungatautari project?

The Kissimmee River project returns the flow of water to the original channel and restores natural flow, a self-sustaining outcome. Ecologists at the Maungatautari reserve will need to maintain the integratity of the fence indefincitiely, an outcome that is not self-sustaining in the long-term.

Secondary production

The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period.

Primary production

The amount of light energy converted to chemical energy (organic compounds) by the autotrophs in an ecosystem during a given time period.

In the terrestrial carbon cycle, the abiotic reservoirs from which living organisms directly obtain their carbon is ________.

The atmosphere

WHAT IF? In the study, "How does temperature affect litter decomposition in an ecosystem?" What factors other than temperature might also have varied across these 21 sites? How might this variation have affected the interpretation of these results?

The availability of water and exposure to light are there factors that may have varied across the sites. Factors such as these are not included in the experimental design could make the results more difficult to interpret. Multiple factors can also be correlated to each other in nature, so ecologists must be careful that the factor they are studying is actually causing the observed response and is not just correlated with it.

MAKE CONNECTIONS Explain how nitrogen and phosphorous, the nutrients that most often limit primary production, are necessary for the Calvin Cycle to function in photosynthesis.

The enzyme rubisco, which catalyzes the first step in the Calvin cycle is the most abundant protein on Earth. Like all proteins, rubisco contains nitrogen, and because photsynthetic organisms require so much rubisco, they also require considerable nitrogen to make it. Phosphorous is also needed as a component of several metabolites in the Calvin cycle and as a component of both ATP and NADPH.

Net ecosystem production (NEP)

The gross primary production of an ecosystem minus the energy used by all autotrophs and heterotrophs for respiration.

Net primary production (NPP)

The gross primary production of an ecosystem minus the energy used by the producers for respiration

Which of the following organisms is incorrectly paired with its trophic level? Cyanobacteria - primary producer grasshopper- primary consumer Zooplankton - primary producer Fungus - detritivore

(A.) Zooplankton-primary producer

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as _______.

(A.) restoration ecology

What has the greatest effect on the rate of chemical cycling in an ecosystem?

(A.) the rate of decomposition in the ecosystem

The Hubbard Brook watershed deforestation experiment yielded all of the following results except which of the following? Most minerals were recycled within a forest ecosystem. Calcium levels remained high in the soil of deforest areas. Deforestation increased water runoff. The nitrate concentration in water draining the deforested area became dangerously high.

(B.) Calcium levels remained high in the soil of deforested areas.

Which of these ecosystems has the lowest net primary production per square meter? A salt march An open ocean A coral reef A tropical rain forest

(B.) an open ocean

Nitrifying bacteria participate in the nitrogen cycle mainly by:

(C.) converting ammonium to nitrate, which plants absorb

If you applied a fungicide to a cornfield, what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)?

(D.) Decomposition rate would decrease and NEP would increase.

What is an example of bioremediation?

(D.) adding seeds of chromium-accumulating plant to soil contaminated by chromium

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

10

Energy transfer between trophic levels is typically only ___________ % efficient

10

If an insect that eats plant seeds containing 100J of energy uses 30J of that energy for respiration and excretes 50J in its feces, what is the insects net secondary production? what is its production efficiency?

20 J; 40 %

Approximately ________ % of energy at one trophic level is passed on to the next highest trophic leave.

5-10

In the transition from each trophic level the food chain to the next trophic level, there is about a __________.

90 % Loss of energy

Detritivore

A consumer that derives, its energy and nutrients from nonliving organism material such as corpses, fallen plant material, and the wastes of living organisms; a decomposer.

What frequently causes eutrophication in lakes?

A nutrient enrichment such as nitrate and phosphate runoffs from land

Eutrophication

A process by which nutrients, particularly phosphorous and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or Cyanobacteria

Nitrifying bacteria convert _______ to _______.

Ammonium...nitrites

Biological augmentation

An approach to restoration ecology that uses organisms to add essential materials to a degraded ecosystem.

Primary Producer

An autotroph, usually a photosynthetic organism. Collectively, autotrophs make up the trophic level of an ecosystem that ultimately supports all other levels.

Limiting Nutrient

An element that must be added for production to increase in a particular area

Decomposer

An organism that absorbs nutrients from nonliving organism material such as corpses, fallen plant material, and the wastes of living organisms and converts them to inorganic forms; a detritivore.

Biogeochemical cycle

Any of the various chemical cycles, which involve both biotic and abiotic components of ecosystems.

________________ is the uptake of nutrients into an organism.

Assimilation

The phosphorous cycle lacks a(n) __________ component.

Atmospheric - Gaseous phosphorous is insignificant.

Nitrogen enters ecosystems through ________________ and ____________ by prokaryotes.

Atmospheric deposition; nitrogen fixation

Photosynthetic organisms are called _________.

Autotrophs

Considering the second law of thermodynamics, would expect the typical biomass of primary producers in an ecosystem to be greater than or less than the biomass of secondary producers in the system? Explain your reasoning.

Because energy conversions are inefficient, with some energy inevitable lost as heat, you would expect that a given mass of primary producers would support a smaller biomass of secondary producers.

A __________________________ diagram summarizes the movements of a chemical element between living and nonliving components of the biosphere.

Biogeochemcial cycle

In ____________________, ecologists use organisms to add essential materials to ecosystems.

Biological augmentation

The use of organisms to add essential materials to degraded systems defines___________.

Biological augmentation - uses organisms to supply necessary nutients that allow damaged habitats to recover more speedily

Restoration ecologists harness organisms to detoxify polluted ecosystems through the process of __________.

Bioremediation

In contrast to ___________, which is a strategy for removing harmful substances from an ecosystem, _________ uses organisms to add essential materials to a degraded ecosystem.

Bioremediation; biological augmentation is

How can ecologists experimentally determine the factor that limits primary production in an ecosystem?

By manipulating the level of the factors of interest, such as phosphorous availability or soil moisture, and measuring responses by primary producers.

Which element is found in all organic compounds?

Carbon

An ecosystem is unlikely to be limited by the supply of ________ because it is obtained from the air.

Carbon - atmospheric carbon, in the form of CO2, is incorporated into living systems by photosynthesis

Breakdown by decomposers of carbon-containing dead plants and animals Assimilation of atmospheric CO2 by plant photosyntehsis Return of CO2 to the atmosphere by animals and plant respiration Return of CO2 to the atmosphere by burning fossil fuels All are key parts of the __________.

Carbon Cycle

Plants obtain carbon from ______.

Carbon dioxide

Where do plants get the carbon they use to make organic molecules?

Carbon dioxide

Before the outbreak the forest was a _______________ (absorbing more CO2 from the atmosphere than it releases) since its NEP value was __________(greater than/less than) zeros.

Carbon sink; greater than

After the outbreak the forest was a _________________ (releasing more carbon to the atmosphere than it absorbed) with a NEP __________ (greater than/less than) zero.

Carbon source; less than

Secondary consumers are animals that eat other animals, thus they are ___________.

Carnivores

Carbon moves from living organism to an abiotic reservoir during the process of ________.

Cellular Respiration

MAKE CONNECTIONS Human actions are causing climate change, thereby affecting Earth's ecosystems - few of which have been affected as greatly as those in the Arctic. Hypothesizes how climate change might cause evolution in arctic tundra populations. Explain.

Climate change may significantly reduce the prexisting small population of primary producers eliminating many of the food chains that exist in the tundra.

A study of metabolic rates in a terrestrial community showed that the energy released by respiration exceeded the energy captured in photosynthesis. What situation is most likely?

Community biomass is decreasing

The producers in aquatic ecosystems include organisms in which of the following groups?

Cyanobacteria; algae; plants; and photoautotrophs

Detritus

Dead organic matter

The proportion of a nutrient in a particular form varies among ecosystems, largely because of differences in the rate of ________.

Decomposition

How does temperature affect litter decomposition in an ecosystem?

Decomposition rate increases with temperature across much of Canada.

Net primary productivity is the difference between the yield of photosynthesis and the consumption of organic fuel in respiration. Primary productivity can be expressed as the biomass of vegetation added to an area of the ecosystem per unit of time. If the energy released by respiration exceeds the energy captured in photosynthesis, biomass (increases/decreases).

Decreases

_____________________ convert organic matter from all trophic levels to inorganic compounds usable by primary producers.

Detritivores

All of the living organisms in your aquarium and the abiotic factors with which they interact is an _______.

Ecosystem

An _____________ consists of all the organisms in a community and the abiotic factors with which they interact. Energy is conserved but released as heat during ecosystem processes. As a result, energy flows through ecosystems (rather than being recycled).

Ecosystem

Organic molecules, such as fats, are a source of ___________.

Energy

An ecosystem regardless of size, has two key emergent properties: _____________ and _______________.

Energy flow; chemical cycling

Why is the transfer of energy in an ecosystem referred to as energy flow, not energy cycling?

Energy passes through an ecosystem, entering as sunlight and leaving as heat. It is not recycled within the ecosystem.

The loss of energy with each transfer in a food chain can be represented by an ____________, in which the net productions of different trophic levels are arranged in tiers.

Energy pyramid

When an organism breaks down organic molecules, some of the energy that had been stored as chemical energy is lost as heat. This happens because _______.

Every energy transfer or transformation increases entropy

If decomposers usually grow faster and decompose material more quickly in warmer ecosystems, why is decomposition in hot deserts relatively slow?

Factors other than temperature, including a shortage of water and nutrients, slow decomposition in hot deserts.

On a global scale, energy __________ ecosystems whereas chemical elements ____________ ecosystems.

Flows through; are recycled in

If you know NPP for an ecosystem, what additional variable do you need to know to estimate NEP? Why might measuring this variable be difficult, for instance, in a sample of ocean water?

For estimates of NEP, you need to measure the respiration of all organisms in an ecosystem, not just the respiration of primary producers. In a sample of ocean water, primary producers and other organisms are usually mixed together, making their respective respiration hard to separate.

The global hydrolic cycle supports a new flow of atmospheric water vapor ___________.

From oceans to land

The main decomposers in an ecosystem are ___________.

Fungi and prokaryotes

A measure of the total primary production in an ecosystem is called _______.

Gross primary production

Organisms in trophic levels above the primary producers are ________, which depend directly or indirectly on the outputs of primary producers for their source of energy.

Heterotrophs

In preparing a site for surface mining and later restoration, why would engineers separate the topsoil from the deeper soil, rather than removing all soil at once and mixing it in a single pile?

If the topsoil and deeper soil are kept separate, the engineers could return the deeper soil to the site first and then apply the more fertile topsoil to improve the success of revegetation and other restoration efforts.

The gas carbon dioxide is an ______.

In It to photosynthesis and an end product of cellular respiration

Minerals are ___________.

Inorganic

How do iron levels affect phytoplankton populations in a marine ecosystem?

Iron stimulates the growth of Cyanobacteria, which convert atmospheric N2 to nitrogenous minerals, stimulating the growth of phytoplankton.

Most of sunlight that reaches Earth ________.

Is not captured for use by living things

What best describes the base of a pyramid of net production?

It contains the energy captured by photosynthesis.

In an ecosystem, what will eventually happen to all incoming energy?

It will be dissipated into space as heat.

Plants use _______ as a source of energy.

Light

Where do plants get the energy to make organic molecules?

Light

Identify the main goal of restoration ecology.

The main goal is to restore degraded ecosystems to a more natural state.

Production Efficiency

The percentage of energy stored in assimilated food that is not used for respiration or eliminated as waste.

Trophic Efficiency

The percentage of production transferred from one trophic level to the next higher trophic level.

Tobacco leaves contain nicotine, a poisonous compound that is energetically expensive for the plant to make. What advantage might the plant gain by using some of its resources to produce nicotine?

The plant benefits from produces nicotine because it provides a mechanical defense mechanism to defend against herbivors, interested in eating tobacco leaves.

Which nutrient limits phytoplankton production along the coast of Long Island?

The researchers concluded that nitrogen is the nutrient that limits phytoplankton growth in this ecosystem because adding phosphorous did not increase Nannochloris growth, whereas adding nitrogen increased phytoplankton density dramatically.

MAKE CONNECTIONS Use the second law of thermodynamics to explain why an ecosystem's energy supply must be continually replenished.

The second law states that in any energy transfer or transformation, some of the energy is dissaipated to the surroundings as heat. For the ecosystem to remain intact this "escape" of energy from the ecosystem must be offset by the continuous influx of solar radiation.

Based on the law of conservation of energy, ecosystem ecologists can make which of the following assertions?

The total amount of energy stored in organic molecules plus the amounts reflected and dissipated as heat must equal the total solar energy intercepted by the Earth.

Gross primary production (GPP)

The total primary production of an ecosystem; the amount of energy from light (or chemicals in chemoautotrophic systems) converted to the chemical energy of organic molecules per unit time

Bioremediation

The use of organisms to detoxify and restore polluted and degraded ecosystems.

Based on these data alone, identify the most appropriate statement about the impact mountain pine beetle outbreaks may have on climate regulation.

These data demonstrate that mountain pine beetle outbreaks can convert forest ecosystems from carbons sinks to carbon sources. A forest that is a carbon source releases more CO2 to the atmosphere than it absorbs, contributing to higher atmospheric CO2 concentrations and an enhanced greenhouse gas effect.

The percentage of energy transferred from one trophic level to the next, called _____________, is typically _______ %. Pyramids of energy and biomes reflect low trophic efficiency.

Trophic efficiency; 10 %

______________where deep, nutrient-rich waters circulate to the ocean surface, have exceptionally high primary production. This fact supports the hypothesis that nutirent availability determines marine primary production.

Upwelling

Nutrient cycling is strongly regulated by _______________. The Hubbard Brook case study showed that logging increases water runoff can cause large losses of minerals.

Vegatation

WHAT IF? You are studying nitrogen cycling on the Serengeti Plain in Africa. During your experiment, a herd of migrating wildabeests grazes through your study plot. What would you need to know to measure their effect on nitrogen balance in the plot?

You would need to know how much biomass the wildebeests ate from your plot and how much nitrogen was contained in that biomass. You would also need to know how much nitrogen they deposited in urine feces.

Primary consumers

animals that feed on producers; ex. herbivores

tertiary consumers (carnivores)

consume secondary consumers

What provides your body with energy?

fats

Chemical elements enter and leave an ecosystem and cycle within it, subject to the ________________________. Inputs and outputs are generally small compared to recycled amounts, but their balance determines whether the ecosystem gains or loses an element overtime.

law of conservation of mass

secondary consumers (carnivores)

obtain their energy by eating primary consumers

The Law of Conservation of Mass

the law that states that matter cannot be created or destroyed in ordinary chemical and physical changes

Ecosystem

the sum of all organisms living in a given area and the abiotic factors with which they interact