# Presentation: 501586

## 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

## Model Calculations of Sunscreen Factors 

**MAA**

- UV +PAR

***Jtot***

***Jo***

**statistical**

**a*ps (********)**

- Sunscreen Factors Ranged from roughly 40-60%

- Moisan & Mitchell 1998

## The Absorption Characteristics of Phaeocystis antarctica

- Moisan and Mitchell (1998)
- Ru Morrison , UNH

## 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.

## Field Samples

- Of Phaeocystis,
- Dinoflagellates & Diatoms

- HPLC
- Analysis

- Packaged

- a*ph (lambda)

- P/S & PP
- Pigments

- UV- MAAs

- Packaged Pigment
- Spectral Analysis

- 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

## 	Approach

- 	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

## Slide 8

## _____________________________________Cruise I:  April 2007Phaeocystis and co-dominated with diatoms such as small chains of SkeletonemaCruise II:  May 2007 (Dinoflagellates (Ceratium, Protoperidium, and heterotrophic dinoflagellates) and DiatomsCruise III:  June 2007Mixture of Dinoflagellates and diatoms_____________________________________ **Confirmed from net tows and epif. quan. cell counts.

## Colonial Phaeocystis Dominated 

- Colonial Phaeocystis Dominated

## Diatom-Dinoflagellates Dominate

## Diatom Dominated

## MAA

- BIOME

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## 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

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## Major marker pigments

**Major marker pigments**

**Ubiquitous**
**     ****Chl *****a***
**Unambiguous**
**   ****Alloxanthin**
**   ****Peridinin**
**   ****Prasinoxanthin**
**Shared    **
**    ****e.g.**
**    ****Fucoxanthin**
**    ****Chl b**
**    ****Zeaxanthin**
**    ****Violaxanthin**

## 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?

## “Jimmy Buffet’s Cheeseburger in Paradise” (Moisan 2008)

- J

- “Jimmy Buffet’s Cheeseburger in Paradise” (Moisan 2008)