Mycosporine-like Amino Acids (MAAs) may serve to photoprotect phytoplankton from UV radiation

1






2
Mycosporine-like Amino Acids (MAAs) may serve to
photoprotect phytoplankton from UV radiation

• Water soluble compounds
• Exhibit Absorption maxima from 310 to 360 nm
• Aminocyclohexenone or aminocyclohexenimine
• conjugated to amino acid or amino alcohol
• Found in dinoflagellates, prymnesiophytes,
  red algae, cyano

Mycosporine-Glycine ?max 310 nm
3
Model Calculations of Sunscreen Factors
UV PAR
Jtot
statistical
aps (l)
MAA
Jo
Sunscreen Factors Ranged from roughly 40-60
Moisan Mitchell 1998
4
The Absorption Characteristics of Phaeocystis
antarctica
Moisan and Mitchell (1998) Ru Morrison , UNH
5
Questions?

• Are there differences between MAA
• content between taxonomic groups?
• What determines MAA variability?
• How does MAA variability relate to other UV
  absorbing constituents e.g. CDOM (Mannino) and
  detritus.

6
Field Samples Of Phaeocystis, Dinoflagellates
Diatoms
Packaged

HPLC Analysis
aph (lambda)
Packaged Pigment Spectral Analysis
P/S PP Pigments
UV- MAAs
Spectral Reconstruction\ Deconvolution
French Press Method
Analysis of pigment Packaging w.r.t. markers
Forward Model Hydrolight to Test algorithms
Inverse Model application Using Developed
algorithms
7

• Approach
• 3 cruises in April, May June 2007
• Collected optical, physiological,
• chemical data
• Processing IOP AOP data
• Approach of utilizing cultures to
• develop MAA standards

8
(No Transcript)
9
_____________________________________Cruise I
April 2007Phaeocystis and co-dominated with
diatoms such as small chains of
SkeletonemaCruise II May 2007
(Dinoflagellates (Ceratium, Protoperidium, and
heterotrophic dinoflagellates) and
DiatomsCruise III June 2007Mixture of
Dinoflagellates and diatoms______________________
_______________ Confirmed from net tows and
epif. quan. cell counts.
10
Colonial Phaeocystis Dominated
11
Diatom-Dinoflagellates Dominate
12
Diatom Dominated
13
BIOME
MAA
14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Assessing Pigment Package Effects

• What is the significance
• of packaging?
• Is packaging spectral?
• We founds significant
• variability in UV region
• due to packaging?
• Problem Models are
• not spectrally corrected

22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
Major marker pigments
Ubiquitous Chl a Unambiguous
Alloxanthin Peridinin Prasinoxanthin Shared
e.g. Fucoxanthin Chl b
Zeaxanthin Violaxanthin
27

• Future Directions
• Understand how UV MAAs are expressed
• at the surface of the ocean as a remote
  sensing
• target
• Can they be seen in remote sensing reflectance?
• Can we assess physiological variability to
  constrain
• algorithms in order to increase accuracy and
  robustness?

28
Jimmy Buffets Cheeseburger in Paradise (Moisan
2008)
J