Chapter 6 Marine Microbes Karleskint Turner Small Key

Chapter 6 Marine Microbes Karleskint Turner Small

Key Concepts • Microbial life in the sea is extremely diverse, including members of all three domains of life as well as viruses.

Marine Viruses Significance: • Marine food webs • Population biology • Diseases of marine organisms

Marine Bacteria • General characteristics – simple, prokaryotic, few genes – reproduce by binary fission – many shapes and sizes

Nutritional Types • Cyanobacteria (blue-green bacteria) – photosynthetic – found in high dissolved oxygen, and produce free oxygen

Nutritional Types • Chemosynthetic bacteria – Use energy from chemical reactions – Less efficient than photosynthesis – Found around hydrothermal vents

Nutritional Types (Heterotrophic Bacteria) • Heterotrophic bacteria – Decomposers – Marine snow

Symbiotic Bacteria • Chemosynthetic bacteria live within tube worms and clams • Some deep-sea or nocturnal animals host helpful bioluminescent bacteria

Archaea • General characteristics – Small – Prokaryotic – Extreme environmental conditions

Archaea • Nutritional Types – Photosynthesizers, chemosynthesizers and heterotrophs – Most are methanogens – Halobacteria thrive at high salinities

Archaea • Hyperthermophiles – Survive at temperatures exceeding 100 o C – Potential for biomedical and industrial application

Fungi • Decomposers, prey, pathogens and symbionts

Fungi • General features – Heterotrohic decomposers

Fungi • Salinity is toxic to fungi, devote energy to removing sodium • Most live on wood from land • Some live on grass in salt marshes • Others live on algae, mangroves or sand

Maritime Lichens • Lichens: mutualistic associations between a fungus and an alga

Diatoms • 2 basic diatom shapes: – Radially symmetrical valves (generally planktonic) – Bilaterally symmetrical valves (generally benthic)

Diatoms • Diatomaceous sediments – Sink and collect on the seafloor – Mined for use as filtering material, a mild abrasive, and for soundproofing and insulation products – Accumulate in siliceous oozes accounting for most of the worlds petroleum reserves

Alveolates • Dinoflagellates – Globular, unicellular (sometimes colonial) with 2 flagella – Most are planktonic, some are benthic and others parasitic – Can be bioluminescent – Bioluminescent Bay, Puerto Rico

Alveolates (Dinoflagellates) • Ecological roles of dinoflagellates – Major component of phytoplankton – Some are parasites of copepods (crustaceans) – Zooxanthellae: symbionts of jellyfish, corals and molluscs

Alveolates (Dinoflagellates) • Harmful Algal Blooms (HABs) – Photosynthetic dinoflagellates undergo a population explosion – Colors the water red, orange or brown – Dinoflagellates that cause HABs produce toxins • Paralytic shellfish poisoning (PSP) occurs in humans • Toxins cannot be destroyed by cooking – Oxygen content of the water may be reduced to deadly levels as bacteria decompose animals killed by dinoflagellate toxins