Podcast
Questions and Answers
Which of the following best describes the relationship between AET (annual amount of water that evaporates and transpires off a landscape) and primary production?
Which of the following best describes the relationship between AET (annual amount of water that evaporates and transpires off a landscape) and primary production?
- High AET is generally correlated with higher primary production, especially in warmer ecosystems. (correct)
- AET is not directly related to primary production.
- High AET generally corresponds to low primary production due to water scarcity.
- Low AET consistently leads to high primary production in all ecosystems.
Sala et al.'s (1988) study of central USA grasslands revealed that primary production was most strongly correlated with which environmental factor?
Sala et al.'s (1988) study of central USA grasslands revealed that primary production was most strongly correlated with which environmental factor?
- Rainfall (correct)
- Soil fertility
- Sunlight hours
- Temperature
Shaver and Chapin's (1986) research in arctic tundra demonstrated that net primary production significantly increased when:
Shaver and Chapin's (1986) research in arctic tundra demonstrated that net primary production significantly increased when:
- Soil pH was adjusted to alkaline levels.
- Herbivore populations were reduced.
- Plots were shaded to reduce evapotranspiration.
- Plots were fertilized. (correct)
Bowman et al. (1993) found that in dry meadows, the primary limiting nutrient for primary production was typically:
Bowman et al. (1993) found that in dry meadows, the primary limiting nutrient for primary production was typically:
In wet meadows, Bowman et al. (1993) determined that primary production was primarily limited by:
In wet meadows, Bowman et al. (1993) determined that primary production was primarily limited by:
Which of the following statements best describes the typical limiting factor for primary production in aquatic ecosystems?
Which of the following statements best describes the typical limiting factor for primary production in aquatic ecosystems?
Experiments in the Experimental Lakes Area in Canada, where lakes were divided into basins and treated differently, demonstrated that adding carbon, nitrogen, and phosphorus to one basin resulted in:
Experiments in the Experimental Lakes Area in Canada, where lakes were divided into basins and treated differently, demonstrated that adding carbon, nitrogen, and phosphorus to one basin resulted in:
In marine environments, the highest rates of primary production by phytoplankton are typically found in regions with:
In marine environments, the highest rates of primary production by phytoplankton are typically found in regions with:
Which combination of environmental factors typically leads to the highest rates of terrestrial primary production?
Which combination of environmental factors typically leads to the highest rates of terrestrial primary production?
What does net primary production (NPP) represent?
What does net primary production (NPP) represent?
How many energy transfers away from primary producers does a secondary consumer represent?
How many energy transfers away from primary producers does a secondary consumer represent?
What is the role of detritivores in the trophic levels?
What is the role of detritivores in the trophic levels?
A researcher measures the gross primary production (GPP) in an ecosystem as 500 $gC/m^2/year$ and the respiration of primary producers as 100 $gC/m^2/year$. What is the net primary production (NPP)?
A researcher measures the gross primary production (GPP) in an ecosystem as 500 $gC/m^2/year$ and the respiration of primary producers as 100 $gC/m^2/year$. What is the net primary production (NPP)?
Which of the following best describes the relationship between actual evapotranspiration (AET) and terrestrial primary production?
Which of the following best describes the relationship between actual evapotranspiration (AET) and terrestrial primary production?
In the context of trophic levels, which of the following statements is most accurate?
In the context of trophic levels, which of the following statements is most accurate?
How does temperature most directly influence terrestrial primary production?
How does temperature most directly influence terrestrial primary production?
Which environmental condition would LEAST likely support high rates of marine primary production?
Which environmental condition would LEAST likely support high rates of marine primary production?
In the Black Sea, if excess phosphates are added but nitrate levels remain constant, what would MOST likely happen to primary production?
In the Black Sea, if excess phosphates are added but nitrate levels remain constant, what would MOST likely happen to primary production?
A researcher observes that increasing the number of plant species in an experimental plot leads to higher primary production. What could BEST explain this phenomenon?
A researcher observes that increasing the number of plant species in an experimental plot leads to higher primary production. What could BEST explain this phenomenon?
Based on the information, which factor would MOST comprehensively influence primary production rates in an ecosystem?
Based on the information, which factor would MOST comprehensively influence primary production rates in an ecosystem?
In an aquatic ecosystem, a scientist observes that increasing algal species richness leads to higher nitrate uptake and biomass. How might this observation be applied to a larger scale environmental management strategy?
In an aquatic ecosystem, a scientist observes that increasing algal species richness leads to higher nitrate uptake and biomass. How might this observation be applied to a larger scale environmental management strategy?
Suppose a coastal region experiences increased nutrient runoff from agricultural land. What INITIAL effect would this MOST likely have on marine primary production and why?
Suppose a coastal region experiences increased nutrient runoff from agricultural land. What INITIAL effect would this MOST likely have on marine primary production and why?
A study investigates the effects of different functional groups of plants (N-fixing legumes and C4 grasses) on primary production. What conclusion would BEST demonstrate the importance of biological influences on chemical and physical factors?
A study investigates the effects of different functional groups of plants (N-fixing legumes and C4 grasses) on primary production. What conclusion would BEST demonstrate the importance of biological influences on chemical and physical factors?
If nutrient enrichment leads to increased chlorophyll concentrations, what can be logically inferred about the relationship between nutrients and phytoplankton in that environment?
If nutrient enrichment leads to increased chlorophyll concentrations, what can be logically inferred about the relationship between nutrients and phytoplankton in that environment?
In the context of lake ecosystems, how does a reduction in planktivorous fish populations typically affect primary production?
In the context of lake ecosystems, how does a reduction in planktivorous fish populations typically affect primary production?
According to Carpenter et al. (1985), what role do piscivorous and planktivorous fish play in lake primary productivity?
According to Carpenter et al. (1985), what role do piscivorous and planktivorous fish play in lake primary productivity?
How does grazing, as observed in the Serengeti, influence the rate of primary production?
How does grazing, as observed in the Serengeti, influence the rate of primary production?
What is a 'trophic cascade,' and how does it relate to the influence of consumers on primary production?
What is a 'trophic cascade,' and how does it relate to the influence of consumers on primary production?
McNaughton's research in the Serengeti showed a positive correlation between rainfall and primary production. How does grazing by large mammals modify this relationship?
McNaughton's research in the Serengeti showed a positive correlation between rainfall and primary production. How does grazing by large mammals modify this relationship?
What combination of factors contributes to compensatory growth in grazed plants, leading to increased primary production?
What combination of factors contributes to compensatory growth in grazed plants, leading to increased primary production?
In the context of bottom-up and top-down controls on ecosystems, how would you classify the influence of nutrient availability and grazing, respectively?
In the context of bottom-up and top-down controls on ecosystems, how would you classify the influence of nutrient availability and grazing, respectively?
A lake ecosystem experiences a sudden increase in the population of piscivorous fish. According to the trophic cascade hypothesis, what is the most likely long-term effect on phytoplankton biomass?
A lake ecosystem experiences a sudden increase in the population of piscivorous fish. According to the trophic cascade hypothesis, what is the most likely long-term effect on phytoplankton biomass?
Why does heavy grazing negatively impact a plant's ability to recover, in relation to primary production?
Why does heavy grazing negatively impact a plant's ability to recover, in relation to primary production?
In the context of trophic dynamics, why is energy transfer between trophic levels considered inefficient?
In the context of trophic dynamics, why is energy transfer between trophic levels considered inefficient?
How does the concept of ecological efficiency relate to the pyramid-shaped distribution of energy among trophic levels?
How does the concept of ecological efficiency relate to the pyramid-shaped distribution of energy among trophic levels?
What is the primary purpose of estimating secondary production in ecosystems?
What is the primary purpose of estimating secondary production in ecosystems?
What methodological approach did Benke use to estimate secondary production in dragonfly larvae?
What methodological approach did Benke use to estimate secondary production in dragonfly larvae?
According to the prey-dependent model, what is the expected impact of increased primary production on secondary consumers (predators)?
According to the prey-dependent model, what is the expected impact of increased primary production on secondary consumers (predators)?
How might grazing intensity influence the ecological efficiency between primary producers and primary consumers?
How might grazing intensity influence the ecological efficiency between primary producers and primary consumers?
What is a key difference between the prey-dependent model and other predator-prey models in predicting secondary production?
What is a key difference between the prey-dependent model and other predator-prey models in predicting secondary production?
Flashcards
Ecosystem Ecology
Ecosystem Ecology
The study of energy, water, and nutrient flows within ecosystems.
Primary Production
Primary Production
The production of new organic matter per unit area in an ecosystem over a period of time.
Gross Primary Production
Gross Primary Production
The total primary production before accounting for respiration.
Net Primary Production
Net Primary Production
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Secondary Production
Secondary Production
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Trophic Level
Trophic Level
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Limits to Terrestrial Primary Production
Limits to Terrestrial Primary Production
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AET and Primary Production
AET and Primary Production
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AET (Actual Evapotranspiration)
AET (Actual Evapotranspiration)
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Grassland Primary Production (USA)
Grassland Primary Production (USA)
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Soil Fertility and Primary Production
Soil Fertility and Primary Production
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Limiting Nutrients in Meadows
Limiting Nutrients in Meadows
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Nutrient Limitation in Aquatic Ecosystems
Nutrient Limitation in Aquatic Ecosystems
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Lake Fertilization Experiment
Lake Fertilization Experiment
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Marine Primary Production Patterns
Marine Primary Production Patterns
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Phosphorus Controls Phytoplankton
Phosphorus Controls Phytoplankton
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High Primary Production Areas
High Primary Production Areas
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Limiting Nutrient
Limiting Nutrient
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Baltic Sea Limiting Nutrient
Baltic Sea Limiting Nutrient
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Primary Producer Diversity
Primary Producer Diversity
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Plant Functional Groups
Plant Functional Groups
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Plant Species Richness Impact
Plant Species Richness Impact
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Productive Plant Groups
Productive Plant Groups
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Algal Diversity Benefits
Algal Diversity Benefits
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Bottom-up controls
Bottom-up controls
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Top-down controls
Top-down controls
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Trophic cascade
Trophic cascade
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Fish and Primary Production
Fish and Primary Production
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Lake Trophic Cascade
Lake Trophic Cascade
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Grazing and Primary Production
Grazing and Primary Production
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Compensatory growth
Compensatory growth
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Optimal Grazing Intensity
Optimal Grazing Intensity
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Heavy Grazing Effects
Heavy Grazing Effects
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Trophic Dynamics
Trophic Dynamics
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Ecological Efficiency
Ecological Efficiency
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Trophic Pyramids
Trophic Pyramids
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Secondary Production units
Secondary Production units
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Prey-Dependent Model
Prey-Dependent Model
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Study Notes
- Ecosystem ecologists study the flow of energy, water, and nutrients within ecosystems.
- Primary production involves the production of new organic matter per unit area in an ecosystem over a specific time.
- Gross primary production (GPP) is the total amount of primary production by all primary producers.
- Net primary production (NPP) is GPP minus respiration, representing the biomass available to consumers.
- Secondary production is the biomass production by consumers over a certain period.
- A trophic level indicates the position of an organism within a food web, determined by the number of energy transfers from primary producers.
- Primary producers are at the first trophic level
- Primary consumers (herbivores and detritivores) are at the second.
- Secondary consumers (carnivores feeding on herbivores and detritivores) are at the third.
- Tertiary consumers are at the fourth trophic level.
Terrestrial Primary Production
- Is generally limited by temperature, moisture, and nutrients.
- Temperature and moisture are highly correlated with primary production; the highest rates occur in warm, moist conditions.
- Rosenzweig (1968) studied the effect of moisture and temperature, plotting the relationship between annual net primary production and actual evapotranspiration (AET).
- AET is the annual amount of water that evaporates and transpires off a landscape.
- Ecosystems that are cold and dry tend to have a low AET.
- Sala et al. (1988) studied elements controlling primary production in grasslands of the central USA.
- Primary production was highest in the east and lowest in the west, correlating with rainfall.
- Shaver and Chapin (1986) discovered that arctic tundra net primary production nearly doubled on fertilized plots.
- Bowman et al. (1993) found that adding nutrients increased primary production in both dry and wet meadows, with nitrogen limiting in dry meadows and nitrogen and phosphorus limiting in wet meadows.
Aquatic Primary Production
- Is generally limited by nutrient availability, particularly phosphorus, which controls phytoplankton biomass in freshwater ecosystems.
- In Canada's Experimental Lakes Area, a lake was divided into two 500,000 m³ basins.
- Adding sucrose and nitrate to one basin increased phytoplankton biomass 2–4x.
- Adding carbon, nitrate, and phosphorus to another basin increased phytoplankton biomass 4–8x.
- Marine phytoplankton primary production is highest in areas with high nutrient availability, such as continental margins and upwelling regions, due to nutrient runoff from land and sediment disturbance.
- Vertical mixing is the main nutrient source in the open ocean, but it is blocked in the tropics by the thermocline.
- Granéli et al. (1990) discovered that primary production in the Baltic Sea is nutrient-limited.
- Increased nitrate led to increased chlorophyll concentrations, while increased phosphates did not, suggesting nitrogen is the limiting nutrient there.
Primary Producer Diversity
- Contributes to higher primary production through both physical and chemical factors, and biological aspects of biodiversity.
- Tilman et al. (2001) examined plants with similar physiological and anatomical characteristics, manipulating the number of species and functional groups in 168 plots.
- Plant species richness correlated with primary production, and N-fixing legume and C4 grass functional groups had higher productivity.
- Cardinale (2011) found that increased nitrate uptake and biomass correlated with increasing algal species richness.
- A study of 1,157 lakes in the USA correlated N/P availability and algal diversity with primary production.
Consumer Influences
- Can influence rates of primary production in aquatic and terrestrial ecosystems through trophic cascades.
- Bottom-up controls are the influences of physical and chemical factors on ecosystems
- Top-down controls are the influences of consumers on ecosystems.
- Carpenter et al. (1985) determined that piscivorous and planktivorous fish cause meaningful differences in primary productivity.
- A trophic cascade occurs when the effects of predators on prey alter more than one trophic level, involving indirect interactions.
- Carpenter and Kitchell (1993) noted that reducing planktivorous fish led to less feeding pressure on zooplankton.
- Large-bodied zooplankton soon dominated, reducing phytoplankton biomass and the rate of primary production.
- McNaughton (1985) approximated that Serengeti grazers consume an average of 66% of annual primary production.
- Grazing increases the growth rate of many grasses and promotes compensatory growth through reduced respiration, self-shading, and improved water balance.
- Compensatory growth is highest at intermediate grazing intensities, with light grazing being insufficient and heavy grazing reducing the plant's capacity to recover.
Secondary Production
- Ecosystems with greater primary production usually support higher levels of secondary production.
- Energy is lost during each energy transfer from one trophic level to the next.
- Food is used for respiration, excretion, and biomass production (growth and reproduction), which is secondary production.
- Lindeman (1942) placed that the ecosystem concept is fundamental in the study of energy transfer within an ecosystem (trophic dynamics).
- Ecological efficiency, varies around 5% to 20%.is the percentage of energy transferred from one trophic level to the next
- Study of dragonfly larvae over 10 months, the cohort approach, is biomass per unit area per unit time.
- The prey-dependent model predicts that increased primary production will increase secondary consumer (predator) abundance but not change primary consumers (herbivores).
- The ratio-dependent model predicts that increased primary production will increase both primary and secondary consumers.
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Description
Explore factors affecting primary production in ecosystems. Topics include the relationship between AET and primary production, limiting nutrients in meadows, and experiments in aquatic ecosystems. Also covered are the effects of increased nutrients on primary production.
