Class in Library

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Mon. Tues. Wed. Thurs.
Fri.
Week of Oct. 20
Class in Library Multimedia Room
Wet, muddy outdoor lab wear closed-toed shoes
Week of Oct. 27
Independent project set-up
T lab switch?
Week of Nov. 3
Exam 2
Forest ecology lab dress for weather
Week of Nov. 10
Independent project analysis
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Nutrient recycling in aquatic systems - where
is it happening?
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• sediments not in contact with pelagic zone
• most sediments are anaerobic
• - reactions are slower

Pelagic zone
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Figure 8.12
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Water below the thermocline may become depleted
of oxygen in summertime Why?
Warm (low density) water
Cool (dense) water
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Fig. 8.16
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Low oxygen in facilitates recycling of some
nutrients (P and Fe) When oxygen is present, P
and Fe combine to form insoluble compounds which
remain in the sediments When oxygen is absent,
P and Fe are soluble and remain in water can
be mixed up into pelagic zone and taken up by
algae
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Fig. 8.17
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Which nutrient is most limiting to
aquatic systems?? What do I mean by most
limiting?
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P - limitation
Housatonic
Goal to decrease N input to LIS by 55 in 15 years
Where does P-limitation switch to
N-limitation? How will changes in nutrient
loading affect species composition and
frequency of algal blooms?
LIS
N-limitation
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Example of using properties of nutrient recycling
in aquatic systems to reduce algal blooms in
freshwater systems
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(No Transcript)
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How could this reduce algal blooms?
Fountain ?
Thermocline ?
oxygen
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Nutrient recycling - Terrestrial systems -
soil - weathering of rock - decomposition
of organic matter - Aquatic systems -
sediments and deep water - reactions slow
(anaerobic) - decomposition not near uptake
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Structure of course
Environmental variability Organisms Ecosystems Pop
ulations Species interactions Communities
Applied Ecological Issues
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Outline Introduction How are populations
defined and measured? How do populations
grow? How does population size change through
time and space?
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Population - group of organisms of the same
species that live in a particular area
Population ecology - focus is on changes in the
number of individuals over time
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Questions asked by population ecologists
What limits population growth? What causes
variability in population size? How do
population in different geographic areas
interact? How does the number of adults in a
population change relative to the number of
juveniles?
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How are populations defined?
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Figure 13.4
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Figure 13.3
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Subpopulation subsets of the population that
are separated and have limited exchange How much
movement is there between subpopulations?
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Figure 13.9
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migration immigration emigration
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Humans like to manage population size of other
organisms Examples???? In order to manage
population size, have to be able to measure it
and have to be able to understand what makes
population change in size
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• How are populations measured?
• What do we measure?
• How?

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• What do we measure?
• Total population size number of individuals
• How they are arranged in space
• How many are in each age or size class

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Population structure the density and spacing of
individuals within a habitat and the proportions
of individuals within each age or size class
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Total population size number of
individuals density x area
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Mark recapture methods

• Catch some individuals and mark them
• Put them back and let them mix
• Recapture some individuals and count how many are
  marked
• Ratio of marked to unmarked gives an estimate of
  population size

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N nM/x
N total number of individuals M number of
marked individuals n number of recaptured
individuals x the number of recaptured
individuals who were marked
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Mark recapture methods
Assumptions

• Population size is the same on the days you
  marked and recaptured.
• All individuals have equal probability of being
  captured.
• Marked individuals were well mixed before
  recapture.

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• What do we measure?
• Total population size number of indivduals
• How they are arranged in space
• How many are in each age or size class

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Figure 13.5
There is a simple statistical test to test for
distribution Mechanisms?
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• What do we measure?
• Total population size number of indivduals
• How they are arranged in space
• How many are in each age or size class

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Outline Introduction How are populations
defined and measured? How do populations
grow? How does population size change through
time and space?
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Growth births deaths immigration
emigration When calculating growth rate,
usually just seeing change in numbers over time
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Populations grow by multiplication rather than by
addition Just like interest in the bank
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Figure 14.3
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Exponential growth

• new individuals are added (born) to population
  continuously
• r per capita growth rate contribution of each
  individual in population

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Exponential growth
dN/dt rN
Rate at which individuals are added growth rate
on a per individual basis x population size
derivative of exponential equation slope of
line
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Figure 14.4
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Exponential vs. Geometric Growth Exponential
continuous reproduction - growth is smooth
curve Geometric discrete breeding seasons -
calculate growth at discrete intervals
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Geometric growth
Growth rate ? population size at one time
point/ size at previous time point N (t1)
? N(t) N(t) N(0) ?t
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Geometric growth N(t) N(0) ?t
Exponential growth N(t) N(0) ert

• er
• Ln ? r

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Figure 14.5
Per capita growth rate constant Rate of
increase dN/dt, increases with N
Exponential
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Figure 14.6