1. SMS 598: Application of Remote and In-situ Ocean Optical Measurements to Ocean Biogeochemistry Quick biology overview and Phytoplankton – taxonomic classification, pigments, photo-adaptation Mary Jane Perry 5 July 2007

2. All you wanted to know about biology, but were afraid to ask

3. Three Super Kingdoms: Eukaryotes Eubacteria Archaea single cells and metazoans Prokaryotes: single cells and consortia Bottom line: great diversity of organisms that interact with light in the ocean

4. All you wanted to know about biology, but were afraid to ask Four basic functions of all organisms: EatAvoid being eatenDefecateReproduce energy & materials * light * reduced inorganics * organic C

5. All you wanted to know about biology, but were afraid to ask Four basic functions of all organisms: EatAvoid being eatenDefecateReproduce toxins swimming bioluminescence morphology (spines, chains) etc.

6. All you wanted to know about biology, but were afraid to ask Four basic functions of all organisms: EatAvoid being eatenDefecateReproduce dissolved organics (e.g., glycolate at high light)

7. All you wanted to know about biology, but were afraid to ask Four basic functions of all organisms: EatAvoid being eatenDefecateReproduce vegetative (asexual) sex – spore/cyst formation – diatom size – other?

8. All you wanted to know about biology, but were afraid to ask Four basic functions of all organisms: EatAvoid being eatenDefecateReproduce energy & materials * light – “primary producers” (phytoplankton; other photon users) * reduced inorganics – “primary producers” (chemosynthetic) * organic C – “consumers” (or secondary producers) consume DOM or POM; mixotrophs

9. For the rest of this morning, will focus on “what’s a phytoplankton?” Photosynthetic (pigmented) Aerobic (oxygenated environment) Oxygenic (oxygen producing; use sunlight) Small, single-celled particle (usually)

10. Three points: 1. Introduce you first to phytoplankton, and a little bit about their role in the ocean 2. What are the proxies based on interaction with light? – particles scatter light – pigments absorb light – chlorophyll a and phycoerythrin fluoresce light 3. How physiology changes the relationship between phytoplankton and their optical proxies

11. Phytoplankton as particles – in the ocean, size matters related to function Size * efficiency of dissolved solute capture * motion – Brownian vs. intentional swimming * efficiency of encounter – surface area for contact * processing – if and how predator handles prey (match/not) * efficiency of aggregation * settling – Stokes Law (implications for carbon cycling) * carbon content * interaction with light – b : scattering (cross sectional area) – a : absorption (volume affects absorption efficiency)

12. Two food webs (with interconnections) big little

14. big particle vs. little particle energy/material cycling

15. “Phytoplankton” as species What we call phytoplankton span the three Super Kingdoms: Archaea – rhodopsin (ATP); really phytoplankton? Eubacteria – cyanobacteria - oxygenic aerobic, anoxygenic, bacterial chlorophyll anaerobic, anoxygenic (sulfur bacteria) Eukaryotes – protists (very diverse) chlorophytes

16. Do species matter? Some functions are species independent: photosynthesis and carbon fixation size - sinking and nutrient uptake Some functions are species specific: N 2 fixation (Trichodesmium) toxins (domoic acid, PSP, etc.) dominate oceanic carbon flux (diatoms) For optical identification, some pigments are taxon specific

17. Synechococcus (~ 1 micron) arrow denotes thylakoid membrane which has both photosynthetic and respiratory functions Diagnostic: phycoerthyrin pigment fluoresces orange (in contrast to chlorophyll, which fluoresces red

18. Prochlococcus ~ 0.7 microns Diagnostic: very small size, lack of orange fluorescence, divinyl chlorophyll a & b

19. Trichodesmium (cyanobacterial nitrogen fixer; warm waters; patchy; Fe may regulate abundance)

20. Prasinophyte

21. Centric Diatoms, Thalassiosira and Chaetoceros

22. Pseudonitzschia (some species have toxin, domoic acid)

23. Alexandrium tamarense Ceratium Dinoflagellates

24. Coccolithophorid, with calcite plates or coccoliths; look at the SeaWiFS website - blooms visible from space

25. Phaeocystis (colonical and single cell) famous for producing foam on northern European beaches

26. Chyrsophyte with silica scales

27. Pigments definition: absorbing compound role:light harvesting for photosynthesis (PS) light protection when too much light (PP) types chlorophylls chlorophyll a - primary PS pigment in all oxygen producers chlorophyll b or c - accessory PS pigments; expand  range; transfer energy to chlorophyll a (divinyl chl a and b) carotenoids light harvesting for photosynthesis (PS) light protection when too much light (PP) phycobilins water soluble pigments; phycoerythrin can fluorescence

28. http://www.nyu.edu/pages/mathmol/library/photo/ www.ch.ic.ac.uk/local/projects/ steer/cloroads.gif Chlorophyll a (absorption peaks will vary, depending on environment – protein complex in membrane, polarity of solvent); in vivo fluorescence porphyrin ring w/Mg ++ phytol tail Degraded pigments: Pheophytin lost Mg ++ ; peak shifts to ~415 Pheophorbide lost Mg ++ and phytol tail

29. Accessory pigments: Chl b and c inside chl a max peaks minor modification of ring in vitro fluorescence Chl c lacks phytol tail

30. Carotenoids conjugated double bonds; role in photosynthesis (PS - absorb blue- green-yellow s) and photoprotection (PP - absorb excess photons, quenching free radicals, triplet oxygen); some taxon specificity

31. Phycobilins (phycobiliproteins) – water soluble cyanobacteria and chryptomonads PUB phycourobilin PE (fluoresces orange) phycoerthyrin PC phycocyanin APC allophycocyanin