Chapter 4: Secondary Production

Question 1

Define secondary production

Answer 1

the production of biomass by heterotrophs (animals, fungi, some bacteria)
-defines what amount of PP is actually converted into heterotroph biomass.
-defines energy requirements for maintaining community growth
“The production of biomass by heterotrophic organisms and is measured as the change of biomass over time”.

Question 2

why is it important to quantify SP?

Answer 2

for understanding food web energy flow as well as the carrying capacity of ecosystems

Question 3

‘Production’ consists of what two parts?

Answer 3

• production of gonads

- production of somatic tissue

Question 4

what is the simplified equation for production?

Answer 4

standing stock
-
(deaths x somatic growth)
=
production

Question 5

growth and mortality are life history patterns that end to correlate with

Answer 5

body size.

small organisms/individuals tend to have higher growth and higher mortality rates

Question 6

what are some methods of measuring the biomass of SP?

Answer 6

wet weight, dry weight, ash free dry weight, organic carbon, joules

Question 7

what are the two main ways of measurement for secondary production?

Answer 7

Cohort-based methods:
-need recognizable cohorts
-based on ind. somatic growth/mortality
-series of measurements thru/out the life span of cohort
-more than 1 cohort, ~accurate age determination may be possible.
2 ways: production of biomass due to growth, elimination of biomass due to mortality

Question 8

what s the ‘estimating SP by the increment summation method’?

Answer 8

• estimate increase in size by individual members of the cohort
• estimate the loss due to mortality
• produce allen plot

Question 9

what is the ‘population surface method’?

Answer 9

• assumes biological rates can be characterized as continuous smooth functions in time
• requires absolute estimates of abundance in each age class and a measure of variance

Question 10

what is the ‘allometric relationships’ method?

Answer 10

• allows for estimates of SP for whole communities by single (few) sampling events
• by utilizing the co-variability btwn size and (production/biomass) ratio.
• > need previous knowledge:
• relationship btwn size and p/b ratio

Question 11

SP of a population is affected by the food availability which is normally affected by:

Answer 11

• temperature
• depth
• trophic level
• trophic efficiency
• primary production

Question 12

what are three methods for production estimates?

Answer 12

• size frequency/Hynes-Hamilton method
• Morini and Bourassa empirical method
• Brey empirical model