Diversity of Life- Eukaryotic Microbes

Diversity of Life Kingdom

  Uni- or multi- cellular   Marine are mostly microscopic   Like bacteria, are important decomposers   Cell walls made of chitin Kingdom Fungi

Kingdom Protista  Three groups:  Animal-like, microscopic, unicellular (protozoans)  Plant-like, microscopic, unicellular (microalgae, phytoplankton)  Plant-like, macro, mostly multicellular (macroalgae, seaweeds)

  Animal-like protists   Heterotrophs – must eat   Single cell (unicellular)   50,000+ species, difficult to classify   Some parasitic Protozoans

 Ameboid organism inside calcareous (CaCO 3 ) shell  Pseudopodia extend through pores in shell  Planktonic or benthic Foraminifera

 Shells become large part of sediment and beach sand Foraminifera

 Shells become large part of sediment and beach sand Foraminifera

 Collecting deep sea sediment for forams Foraminifera

 Important indicators of past climate  Cold vs. warm species present  Chemical composition of shells Foraminifera

  Also ameboid, with pseudopodia   But have silica (SiO 2 ) shell (like glass)   Mostly planktonic   Shells also become part of the sediment Radiolarians

 Hair-like cilia for locomotion and feeding  Tintinnids form vase-like shell  Important part of the microbial loop Ciliates

  Autotrophs are “primary producers”   The synthesis of organic matter from carbon dioxide (CO 2 ) CO 2 + H 2 O + light → C 6 H 12 O 6 + O 2 (sugar) Primary Productivity

  Measured as grams of carbon bound into organic matter per square meter of ocean surface per year g C / m 2 / yr   Entire oceans: 2.5x10 16 gC/yr (25 billion tons!)

 Multicellular benthic are more productive per unit area  Pelagic phytoplankton (photosynthesizing microorganisms in water) are most important (>98%) in total production Primary Productivity

 Geographic variation  Seasonal variation  Photosynthesis requires light and nutrients

Primary Productivity

Upwelling

NASA  Deep nutrient-rich waters return to surface  Phytoplankton (microalgae) blooms  More food for animals

Primary Producers   Prokaryotes (photosynthetic & chemosynthetic)   Domain Bacteria   Domain Archaea   Eukaryotes (photosynthetic)   Kingdom Protista   Unicellular algae (diatoms, dinoflagellates, coccolithophorids)   Multicellular algae (green, brown, red)   Kingdom Plantae   Seagrasses   Salt marsh plants   Mangroves

Diatoms  Variety of shapes  Can form chains  Mostly planktonic  Cooler waters (temperate, polar)

Diatoms  Silica (SiO 2 ) glass cell walls, spines  Oil droplets, air vacuoles for buoyancy  Chlorophyll a & c, carotenoid pigments

Diatoms  Asexual reproduction in phytoplankton and protozans:  Single cells divide rapidly in good conditions, form blooms  Offspring are genetic clones of parent

Diatoms  Shells become large part of sediment  Fossilized diatom shells – many uses

Dinoflagellates  Two flagella for movement  Cellulose cell wall plates  Chl. a & c, carotenoids  Warmer waters (tropics)

Dinoflagellates Bioluminescence

Dinoflagellates Zooxanthellae – symbiotic dinoflagellates inside sponges, jellyfish, anemones, corals, giant clams

Dinoflagellates  “Red tides” – harmful phytoplankton blooms  Red, orange, brown, green  Increase with nutrient pollution  Neurotoxins:  Brevetoxin  Saxitoxin (paralytic shellfish poisoning)  Ciguatoxin (ciguatera fish poisoning)

Coccolithophorids  Coccoliths – calcareous (CaCO 3 )  Chl. a & c, carotenoid pigments  Emiliania huxleyi – most important species globally

Coccolithophorids  Coccolith bloom as seen from space  Plates become large part of sediment  White chalk cliffs of Dover, England