Chapter 18: Primary & Secondary Production PDF - McGraw-Hill

Chapter 18 Primary and Secondary Production © 2019 McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education. ...

Chapter 18 Primary and Secondary Production © 2019 McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.  Outline Concept 18.1 Terrestrial primary production is generally limited by temperature, moisture, and nutrients. Concept 18.2 Aquatic primary production is generally limited by nutrient availability. Concept 18.3 Primary producer diversity contributes to higher primary production. Concept 18.4 Consumers can influence rates of primary production in aquatic and terrestrial ecosystems through trophic cascades. Concept 18.5 Ecosystems with greater primary production generally support higher levels of secondary production. © 2019 McGraw-Hill Education.  Introduction Ecosystem ecologists study flows of energy, water, nutrients in ecosystems. Primary production – production of new organic matter per unit area in ecosystem during some period of time. Gross primary production – total amount of primary production by all primary producers. Net primary production – gross primary production minus respiration; the amount of biomass available to consumers. Secondary production – biomass production by consumers during some period of time. © 2019 McGraw-Hill Education.  Trophic Levels Trophic Level – position in a food web. Determined by number of energy transfers from primary producers to current level. Primary producers occupy first level. Primary consumers occupy second level. Herbivores and detritivores. Secondary consumers occupy third level. Carnivores feeding on herbivores, detritivores. Tertiary consumers occupy fourth level. © 2019 McGraw-Hill Education.  18.1 Patterns of Terrestrial Primary Production Terrestrial primary production is generally limited by Temperature. Moisture. Nutrients. Temperature and moisture are most highly correlated with primary production. Highest rates occur under warm, moist conditions. © 2019 McGraw-Hill Education.  Actual Evapotranspiration and Terrestrial Primary Production Rosenzweig (1968) estimated influence of moisture and temperature on rates of primary production. Plotted relationship between annual net primary production and annual actual evapotranspiration (AET). AET – annual amount of water that evaporates and transpires off a landscape. Cold dry ecosystems tend to have low AET. © 2019 McGraw-Hill Education.  AET and Terrestrial Primary Production Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Primary Production in Central Grassland Sala et al. (1988) studied factors controlling primary production in grasslands of central USA. Highest in east, lowest in west. Correlated significantly with rainfall. Models from Rosenzweig and Sala did not completely explain variation in primary productivity. © 2019 McGraw-Hill Education.  Soil Fertility and Terrestrial Primary Production Significant variation in terrestrial primary production can be explained by differences in soil fertility. Shaver and Chapin (1986) – arctic tundra net primary production nearly doubled on fertilized plots compared to unfertilized plots. Bowman et al. (1993) found adding nutrients increased primary production in dry and wet meadows. N is limiting in dry meadow; N and P in wet. © 2019 McGraw-Hill Education.  Effect of Adding Phosphorus and Nitrogen Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  18.2 Patterns of Aquatic Primary Production Aquatic primary production is generally limited by nutrient availability. Patterns and Models. Quantitative relationship between phosphorus and phytoplankton biomass. Nutrients, especially phosphorus, controls phytoplankton biomass in freshwater ecosystems. © 2019 McGraw-Hill Education.  Whole-Lake Experiments on Primary Production Experimental Lakes Area in Canada. Lake divided into two 500,000 m3 basins. Sucrose, nitrate added to one basin. Phytoplankton biomass increased 2 − 4x. Carbon, nitrate, phosphorus to one basin. Phytoplankton biomass increased 4 − 8x. © 2019 McGraw-Hill Education.  Global Patterns of Marine Primary Production Highest rates of primary production by marine phytoplankton are generally concentrated in areas with higher levels of nutrient availability. Highest rates along continental margins and in areas of upwelling. Nutrient run-off from land. Sediment disturbance. Open ocean tends to be nutrient poor. Vertical mixing is main nutrient source. Blocked in tropics by thermocline. © 2019 McGraw-Hill Education.  Variation in Marine Primary Production Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Nutrient Enrichment in Black Sea Granéli et al. (1990) gathered results suggesting rate of primary production in Baltic Sea is nutrient limited. Increased nitrate led to increased chlorophyll concentrations; increased phosphates did not. Nitrogen appears to be limiting nutrient, not phosphorus. © 2019 McGraw-Hill Education.  18.3 Primary Producer Diversity Primary producer diversity contributes to higher primary production. Physical and chemical factors affect rates of primary production. Biological factors also influence rates. Several aspects of biodiversity are important to primary production and other ecological processes. © 2019 McGraw-Hill Education.  Terrestrial Plant Diversity and Primary Production Tilman et al. (2001) examined plant functional groups, plants with similar physiological and anatomical characteristics. Manipulated number of species and functional groups that were present in 168 plots. Plant species richness correlated with primary production. N-fixing legume and C4 grass functional groups had higher productivity. Biological influences can be just as important as chemical and physical factors. © 2019 McGraw-Hill Education.  Plant Species Richness and Primary Production Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Algal Diversity and Aquatic Primary Production Primary producer diversity increases primary production in experimental aquatic ecosystems. Cardinale (2011) found increase in nitrate uptake and biomass with increasing algal. species richness. These patterns can be extrapolated to larger scales. Study of 1,157 lakes in USA found correlation of N and P availability and algal diversity with primary production. © 2019 McGraw-Hill Education.  18.4 Consumer Influences Consumers can influence rates of primary production in aquatic and terrestrial ecosystems through trophic cascades. Primary production is affected by consumers. Bottom-up controls – influences of physical and chemical factors on ecosystems. Top-down controls – influences of consumers on ecosystems. © 2019 McGraw-Hill Education.  Piscivores, Planktivores, and Lake Primary Production Carpenter et al. (1985) proposed piscivorous and planktivorous fish can cause significant deviations in primary productivity. Influence of consumers on lake primary productivity propagates through food webs. Trophic cascade – effects of predators on prey can alter more than one trophic level. Trophic cascades involve indirect interactions. © 2019 McGraw-Hill Education.  Trophic Cascade Hypothesis Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Lake Trophic Cascade Carpenter and Kitchell (1993). Reduction in planktivorous fish populations led to reduced feeding pressure on zooplankton. Large-bodied zooplankton soon dominate. Reduced phytoplankton biomass and rate of primary production. Consistent with reported negative correlation between zooplankton body size and primary production. © 2019 McGraw-Hill Education.  Predicted Effects of Piscivores Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Grazing by Large Mammals and Primary Production on the Serengeti McNaughton (1985) estimated Serengeti grazers consume an average of 66% of annual primary production. Rate of primary production in the Serengeti is positively correlated with rainfall quantity. Grazing can increase primary production. Increases growth rate of many grasses. Compensatory growth. Lower respiration, reduced self-shading, improved water balance. © 2019 McGraw-Hill Education.  Compensatory Growth McNaughton found compensatory growth highest at intermediate grazing intensities. Light grazing insufficient to produce compensatory growth. Heavy grazing reduces plant’s capacity to recover. © 2019 McGraw-Hill Education.  Grazing Intensity and Primary Production Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  18.5 Secondary Production Ecosystems with greater primary production generally support higher levels of secondary production. With each energy transfer from one trophic level to another, some is lost. Food ingested is used for respiration, excretion, and production of biomass (growth and reproduction), or secondary production. © 2019 McGraw-Hill Education.  A Trophic Dynamic View of Ecosystems Lindeman (1942) concluded the ecosystem concept is fundamental to the study of energy transfer within an ecosystem (trophic dynamics). Suggested grouping organisms within an ecosystem into trophic levels. Each feeds on level immediately below. Ecological efficiency is the percentage of energy transferred from one trophic level to the one above it. Varies from about 5% to 20%. Results in pyramids-shaped distribution of energy among trophic levels. © 2019 McGraw-Hill Education.  Trophic Pyramids Copyright © McGraw-Hill Education. Permission required for reproduction or display. Access the long description slide. © 2019 McGraw-Hill Education.  Estimating Secondary Production Secondary production is key to understanding energy flow in ecosystems. Benke’s approach to estimating secondary production was to follow a cohort over time. Study of dragonfly larvae over 10 months. Secondary production often expressed as biomass per unit area per unit time. © 2019 McGraw-Hill Education.  Linking Primary Production and Secondary Production Predictions of the relationship between primary and secondary production depend on which predator-prey model is used. The prey-dependent model predicts that increased primary production will lead to an increase in secondary consumer (predators) abundance but no change in primary consumers (herbivores). The ratio-dependent model predicts that increased primary production will lead to an increase in both primary and secondary consumers. © 2019 McGraw-Hill Education. © 2019 McGraw-Hill Education.  Review Introduction. Patterns of Terrestrial Primary Production. Patterns of Aquatic Primary Production. Primary Producer Diversity. Consumer Influences. Secondary Production. © 2019 McGraw-Hill Education.