Welcome to EEMB 151250

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Welcome to EEMB 151/250
Phytoplankton Photoecology
When Tuesday, Thursday 1100 AM-1215 PM Where
Chemistry 1171 Instructor Professor Barbara
Prézelin Office Hours Tuesday, Thursday
1230-130 PM in Bio II room 2137.
Thalassiosira, diatom
4 handouts today

• Syllabus
• List of reading, online and CDROM
  assignments for Weeks 1-2
• 3. Chapter 1. The phycology of
  phytoplankton
• CDROM Phytopia
• Not available on website, only available in
  class

2

• 4 quizzes 60 of grade (15 each) April 13,
  April 27, May 11, May 25
• Final 40 of grade, Wednesday June 14,
  noon-3PM
• Extra credit opportunities for undergraduates.
  To be announced.
• For graduate students short paper make
  appointment, Due May 2nd
• Reading Assignments NO TEXTBOOK, course
  material will be either handed out in class or on
  line assignments
• Course website http//mentor.lscf.ucsb.edu/cours
  e/spring/eemb151/
• login eemb151 password photoecology

Chaetoceros debilis, diatom
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Lecture and quiz schedule
April 4 Introduction and assignments April
6 Sunlight from a phytoplankton perspective April
11 Biological light absorption positive and
negative effects. April 13 Photosynthesis Light
harvesting pigments and photosystem I and
II. April 18 Photoregulation of light harvesting
pigments and photosystem I and II. April
20 Photosynthetic carbon fixation and related
metabolism April 25 Photoregulation of
photosynthetic carbon fixation and related
metabolism April 27 Photosynthesis-Irradiance
curves May 2 Quantum efficiencies and biological
action spectra May 4 Bio-optical modeling of
primary production May 9 Bio-optical modeling of
primary production May 11 Photoregulation of cell
movement and buoyancy May 16 Daynight cycles and
biological clocks May 18 Examples and
consequences of environmental timekeeping May
23 Ozone, UVB radiation and primary
production May 25 UV photobiology within
phytoplankton May 30 UV photoecology of different
phytoplankton communities June 1 Bio-optical
models of primary production corrected for UV
effects. June 6 on line lecture
Bioluminescence June 8 Catch up and Review
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Course topics and content build on those
presented in EEMB 142B
http//www.cem.msu.edu/reusch/VirtualText/Spectrp
y/UV-Vis/spectrum.htm
For review from EEMB 142B, see lectures by Nelson
at http//mentor.lscf.ucsb.edu/course/winter/eemb1
42b/lecture/
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Photoecology

• encompasses the fields of photobiology,
  organismal physiology, and ecology.

• Most photoregulated processes are based on
• Light --gt Photoreceptor --gt Photoresponse --gt
  Consequences

• Best example of Photoreceptor in Phytoplankton
• photosynthetic light absorption by
  pigment-protein complexes located on surface or
  embedded in thylakoids found in chloroplasts of
  eukaryote algae

Q What are the major photosynthetic pigments
and the phytoplankton group(s) in which they
occur?
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Best Example of Photoresponses in
Phytoplankton is Photosynthesis

• excitation energy transduction
• fluorescence, delayed light emission, heating
• photochemistry,
• electron transfer, leading to
• NADPH reduction,
• proton (H) and phosphate (PO4) transfer
• leading to ATP synthesis
• These photosynthetic light reactions
• occur as a linear chain

What are some consequences of these
photoresponses?
Hint ATP and NADPH2 are confined to the
chloroplast

• CO2 to first stages of C metabolism

• NO3 --gtNH4 to first stages of protein synthesis

• Heat of surroundings increases

• Ionic state of chloroplast changes

From next weeks readings
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Other Examples of Photoresponses in Phytoplankton
Chaetoceros, diatom

• Photoinhibition, Photodamage, Photorepair
• light disruption of chemical bonds within
  enzymes, DNA and light induced genetic expression
  as part of repair process.

• Photooxidation O2 radical formation,
  Photoquenching
• usually occurs at high irradiances when excess O2
  is formed photosynthetically

• Photomovement
• phototaxis, bouyancy and distribution of
  organelles within a cell

• Photoperiodicity
• activities or properties that change with changes
  in lightdark (LD) cycle
• Photorhythmicity
• changes in activities or properties regulated
  by a biological clock

modifiers
???
???
feedback
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Photoecology also includes light-release
processes.

• Photosynthetic Fluorescence, Phosphorescence,
  Delayed Light Emission
• of orange, red, and far red light (e.g. gt550 nm)
• Reemission of absorbed light but at
• longer wavelengths than that absorbed
• Difference is in time lag before
• light emission occurs

• Bioluminescence chemical formation of light in
  scintillons outside of chloroplast
• not all phytoplankton are bioluminescent
• not all bioluminescence in the sea is due to
  phytoplankton, just most of it
• light produced by phytoplankton is usually blue
  or green (e.g. lt500 nm)

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Light --gt Photoreceptor --gt Photoresponse --gt
Consequences

• Aims of the course on Phytoplankton Ecology are
  to facilitate your abilities
• 1. To obtain a mechanistic understanding of the
  photoresponses of phytoplankton, especially
  regarding bio-optical modeling.
• 2. To appreciate how photoresponses determine
  the optimal ecological niche for different
  phytoplankton species, groups and communities.
• 3. To recognize how the ever changing properties
  of natural light fields are anticipated, induce
  adaptive responses and thereby optimization of
  phytoplankton growth and/or survival.
• 4. To know how to recognize the detrimental
  effects of light on cell biology and what
  defenses phytoplankton might employ.
• 5. To weave the above knowledge into an
  understanding of the dynamic life of
  phytoplankton in natural and increasingly
  unnatural environments.

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First, the players Phytoplankton 1. Need to
know groups and distinguishing features, as well
as environmental influences. This is
considered review from EEMB 142B, not new
material. For review, see Lectures 1-7 at
http//mentor.lscf.ucsb.edu/course/winte
r/eemb142b/lecture/ 2. To increase your
appreciation of the individuality of
phytoplankton species, you will receive a
PHYTOPIA CD-ROM to explore.
PICK UP CD-ROM AT END OF CLASS, only if you
intend to take class
Now, for a demonstration of PHYTOPIA