Chlorophyll pigment is often equated with phytoplankton biomass Lecture Phytoplankton

Transcription

1 Chlorophyll pigment is often equated with phytoplankton biomass Lecture Phytoplankton Phytoplankton pigments influence ocean color

2 Phytoplankton Phyto (Greek, plant) Plankton (Greek, drifter) Autotroph organisms that can synthesize organic compounds, primary producers By size Picoplankton (0.2-2 μm) -Dominant size in the sea. Nanoplankton (2 20 μm) Net plankton ( >> 20 μm) caught by standard plankton nets

3 The Taxonomic Groups of Phytoplankton: An Overview 1. Bacteria (prokaryotes) Eubacteria (heterotroph) Archebacteria or Archaea (heterotroph) Cyanobacteria (phototroph) "real Cyanobacteria" filamentous cyanobacteria, fix nitrogen coccoid cyanobacteria Prochlorophytes (recently made a new division) 2. Algae (eukaryotes) Chromophyta (possess chl a and c) Cryptophyceae Dinophyceae Chrysophyceae Prymnesiophyceae Bacillariophyceae (diatoms) Raphidophyceae Chlorophyta (possess chl a and b) Chlorophyceae Prasinophyceae Euglenophyceae Rhodophyta (possess chl a and biliprotein)

4 Kingdom Protista (the Protists) Kingdom Protista is the trouble-maker of the classification system Can be autotrophic or heterotrophic Can be unicellular or multi-cellular But all are eukaryotic! (Domain Eukarya) Protists

5 Protists, the most nutritionally diverse of all eukaryotes, include: Photoautotrophs, which contain chloroplasts Heterotrophs, which absorb organic molecules or ingest larger food particles Mixotrophs, which combine photosynthesis and heterotrophic nutrition

6 Protistan Anatomy

7 Algae Algae is an informal term for a large, diverse group of eukaryotes that are not necessarily closely related and are thus polyphyletic. have chlorophyll as their primary photosynthetic pigment. lack many of the distinct cell and tissue types, such as stomata, xylem and phloem, that are found In land plants. Algae lack the various structures that characterize land plants, such as the roots, leaves, cell wall, and flowers.

8 Plants evolved from green algae

9 OLDER SCHEMES SERVE A PURPOSE Jeffrey and Vesk UNESCO volume

10 Diatoms Diatoms are unicellular, although many species aggregate to form chains Diatom cells are enclosed by cell walls made of silica; this glassy shell or frustule consists of 2- tightly fitting halves

11 Diatoms The glass frustule allows light to pass through so that photosynthetic pigments can capture light energy for photosynthesis - UV protection? - Aid in sinking? - Protection from predation?

12 Diatoms Diatoms are very important primary producers in temperate and polar regions Account for a large share of the organic carbon produced on Earth Favorable environmental conditions (light and nutrients) promote periods of rapid reproduction known as blooms The glass frustules of dead diatoms eventually settle to the sea floor; diatomaceous ooze

13 Diatom reproduction The two halves of the shells (the box and the lid) separate. Each half then produces a new half to fit inside itself. - one of the new diatoms will be smaller than the original. As they continue reproducing this way, half of the diatoms will get smaller and smaller. one-quarter of their original size, they begin to reproduce sexually, producing gametes that join to become a fertilized cell known as a zygote.

14 Ecologically important Phylum Dinoflagellata Primary producers in marine environments photosynthetic varieties Commonly have two flagella Either photosynthetic or herbivores Some species are bioluminescent Zooxanthellae gensome species are responsible for red tides Release toxins that paralyze or kill fish Protozoans then feed on fish Can affect humans be affecting the respiratory and nervous systems, as well as causing sores to develop.

15 Flagella 3 µm

16 Dinoflagellates

17 Dinoflagellates Some lack chlorophyll and are only heterotrophic, but are bioluminescent Noctiluca = night light. Ingests particulate matter through phagocytosis. Noctiluca Some are parasitic on invertebrates, vertebrates and other protozoans.

18 Zooxanthellae (Dinoflagellate Symbionts) Dinoflagellates protection, nitrogen and carbon dioxide Anemones oxygen and nourishment

19 www2.watertown.k12.wi.us/pagesfifth_grade_websites.cfm

20 Corals and environmental change A water temperature change of only 1 C above the normal summer high temperature for a few weeks leads to coral bleaching Coral expels zooxanthellae or the zooxanthellae expels itself El Niño events can drive coral bleaching May be reversible corals can re-acquire new zooxanthellae if the stress is not too severe

21 Life cycle of dinoflagellates

22 Cysts of dinoflagellates Figure 1. Resting cysts of Scripsiella sp. (a), Alexandrium pseudogoniaulax (b),protoceratium reticulatum (c), A. taylori (d), A. tamarense (e), Protoperidinium oblongum(f), Kryptoperidinium foliaceum (g), and Gymnodinium catenatum (h). Scale bar: 10 µm.

23 Immobilising and eating metazooplankton. Karlodinium armi ger ganging up and munching on a polychaete larva (Berge et al. 2012)

24 Coccolithophorid bloom Emiliana huxleyi SeaWiFS Project and ORBIMAGE

25 Coccolithophorids Coccolithophorids are unicellular protists covered with ornamental plates made of calcium carbonate (CaCo 3 ) Form seasonal blooms in North Atlantic Produce dimethyl sulfide, which alters climate patterns! Long considered to be the smell of the sea

26 Class Cryptophyceae Biflagellate, ventral gullet with trichocysts, accessory pigments (phycobilins, xanthophylls, carotenes) nannoplankton (2-20um) in North Sea spring blooms Cryptomonas Cryptomonas Massive blooms of Mesodinium in upwelling zones (Peru, Baja California)

27 Cyanophyta = cyanobacteria or blue-green algae Prokaryote Eubacteria organelles lacking, Prokaryotes (without true nucleus) Unicellular, colonial, filamentous forms Chl a + Phycocyanin (blue), Phycoerythrin (red), Zeaxanthin Heterocysts & N-fixation The largest and most diverse group of photosynthetic bacteria, which was previously known as blue green algae.

28 Cyanophyta Stromatolites Bermuda, Shark Bay 3.5 Bio 600 Mio O 2 production red bands (FeOx) Warm, low energy, low grazing Between 2.5 and 3 billion years ago, cyanobacteria started using the energy from light to split water, releasing oxygen into the anaerobic, reducing environment

29 Synechococcus Discovered in 1979 very small (ca. 1 µm) contains phycoerythrin can fluoresce orange or red reprinted from Johnson and Sieburth princeton/projects/cyanopigs/data.htm

30 Prochlorococcus Discovered in 1988 Very small (<1.0 µm) Divinyl chl a Most abundant autotroph on earth Contributes 30-80% of primary production in the world's oligotrophic oceans reprinted from Johnson and Sieburth 1979

31 Trichodesmium (Oscillatoria thiebautii) Forms aggregates Fixes nitrogen Can migrate vertically May transport phosphate from depth to near surface New production transports more C Trichodesmium bloom trichodesmium/tricho-01.html

32 Chlorophylls: Reflect mainly green light» Chlorophyll a, b, c, d» Divinyl chlorophyll Carotenoids: Reflect mainly orange and yellow» Fucoxanthin» Beta-carotene Phycobilins (proteins): Reflect mainly blue-green or reddish» Phycocyanin (blue-green algae)» Phycoerythrin

33 Chlorophyll a Light harvesting pigment All photosynthetic organisms have it (photosynthetic cyanobacteria too)

34 Absorbance (excitation) and fluorescence (emission) wavelengths of chlorophyll Fluorescence is the emission of light by a substance that has absorbed light The emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation.

35 Carotenoids Organic pigments that are found in the chloroplasts of plants and some other photosynthetic organisms Carotenoids absorb wavelengths ranging from nanometers (violet to green light). This causes the compounds to be deeply colored yellow, orange, or red. Absorb light energy for use in photosynthesis, and they protect chlorophyll from photodamage.

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38 Phycobilisome in Synecoccous Phycobilins - Blue and red pigments, watersoluble - Open chain tetrapyrrols bound to proteins - Absorbance at yellow-orange - Three types in Cyanobacteria: C-Phycocyanin (blue) Allophyocyanin (blue) C-Phycoerytrhin (red)

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