The Microbial World

1. The Microbial World

3. Prokaryotes Vs. Eukaryotes

4. Mircrobes of the Ocean

5. Primary Producers Are the organisms that produce bio-mass from inorganic compounds (autotrophs). -Photosynthetic autotrophs Phytoplankton – Cyanobacteria Algae Diatoms Dinoflagellates Plants -Chemosynthetic autotrophs – release energy from chemical compounds such as H2S & CH4 Archaea – (Hydrothermal vents) Bacteria – nitrosomonas and nitrobacter -Heterotrophs – energy from organic matter by respiration “Decomposers” Bacteria Fungi

6. Phytoplankton • photosynthesizing microscopic organisms (autotrophs) that inhabit the upper sunlit layer of almost all oceans and bodies of fresh water • They form the base of the ocean food chain. • phytoplankton are a diverse group, incorporating protists eukaryotes and both bacterial and archaebacteria prokaryotes

7. CONSUMERS Aerobic respiration Zooplankton Animals Oxygen Consumed by Aerobic respiration Consumed by Die Wastes DECOMPOSERS PRIMARY PRODUCERS Chemo-synthetic bacteria Anaerobic bacteria Aerobic bacteria and fungi Photo-synthesizers Die Cyanobacteria Phytoplankton Multicellular algae Plants Aerobic metabolism Fermentation Consumed by Nutrients released Nitrogen Sulfur Phosphorus Carbon dioxide Stepped Art Fig. 6-6, p. 131

8. Bacteria • General characteristics • simple, prokaryotic organization: no nucleus or membrane-bound organelles, few genes, cell wall • Can live in both aerobic(with O2) and anaerobic (without O2) environments • reproduce asexually by binary fission • many shapes and sizes • bacillus—rod shape • coccus—spherical shape • Spirillum – cork screw shape

9. Bacteria • Bacteria usually have one of three different cell shapes Coccus (Sphere-shaped) Ex: Streptococcus Bacilli (rod-shaped) Ex: Lactobacillus Spirillum (Spiral-shaped) Ex: Spirillium

10. Cyanobacteria (blue-green bacteria) • Photosynthetic bacteria which are found in environments high in dissolved oxygen, and produce free oxygen • Usually found in low depths of ocean • Contain chlorophyll a and b • First photosynthetic organisms on earth

11. Cyanobacteria • Form associates called stromatolites—a coral-like mound of microbes that trap sediment and precipitate minerals in shallow tropical seas – 3.2 billion years old

12. Algal Blooms • algal bloom (large concentrations of aquatic microorganisms usually phytoplankton) • Caused by cyanobacteria or dinoflagellates that are often green, but they can also be other colors such as yellow-brown or red • high concentrations • Can produce some of the most powerful toxins known harmful algal blooms (HABs), which are red tides caused by the ProtistDinoflagellates or Diatoms • Mass killings the production of neurotoxins which cause mass mortalities in fish, seabirds, sea turtles, and marine mammals • human illness or death via consumption of seafood contaminated by toxic algae

13. Algal Blooms • algal bloom (large concentrations of aquatic microorganisms usually phytoplankton) • Caused by cyanobacteria or dinoflagellates that are often green, but they can also be other colors such as yellow-brown or red • high concentrations • Can produce some of the most powerful toxins known harmful algal blooms (HABs), which are red tides caused by the ProtistDinoflagellates or Diatoms • Mass killings the production of neurotoxins which cause mass mortalities in fish, seabirds, sea turtles, and marine mammals • human illness or death via consumption of seafood contaminated by toxic algae

14. Red Tides

15. Nitrogen Fixation • Nitrogen fixation: process that converts molecular nitrogen dissolved in seawater to ammonium ion • major process that adds new usable nitrogen to the sea • only some cyanobacteria and a few archaeons with nitrogenase (enzyme) are capable of fixing nitrogen

16. Nitrification • Nitrification: process of bacterial conversion of ammonium (NH4+) to nitrite (NO2-) and nitrate (NO3-) ions • bacterial nitrification converts ammonium into a form of nitrogen usable by other primary producers (autotrophs) • Nitrosomonas and Nitrobacter

17. NITRIFICATION NITROGEN FIXATION Dissolved nitrogen (N2) Animal wastes recycled by microorganisms Nitrogen-fixing bacteria, cyanobacteria Ammonia (NH3) +Hydrogen (H2) Ammonium (NH4+) 2 N Bacteria +Oxygen (O2) +Hydrogen (H2) Nitrite (NO2–) Ammonia (NH3) Bacteria +Oxygen (O2) Nitrate (NO3–) Microorganisms Marine plants Phytoplankton Algae Stepped Art Fig. 6-11, p. 135

18. Other photosynthetic bacteria • anaerobic green and purple sulfur and non-sulfur bacteria do not produce oxygen • the primary photosynthetic pigments are bacteriochlorophylls • sulfur bacteria are obligate anaerobes (tolerating no oxygen) • non-sulfur bacteria are facultative anaerobes (respiring when in low oxygen or in the dark and photosynthesizing anaerobically when in the presence of light)

19. Heterotrophic bacteria • decomposers that obtain energy and materials from organic matter in their surroundings • return many chemicals to the marine environment through respiration and fermentation • Aerobic Respiration • Organic matter + O2 ---> CO2 + H2O + chemical energy • Anaerobic Respiration • Organic matter + H+ ---> CH4 + chemical energy

20. Symbiotic Bacteria • Many bacteria have evolved symbiotic relationships with a variety of marine organisms • Endosymbiotic theory • Mitochondria and chloroplasts evolved as symbionts within other cells • Chemosynthetic bacteria live within tube worms and clams • Some deep-sea or nocturnal animals host helpful bioluminescent bacteria • photophores • embedded in the ink sacs of squid

21. Symbiotic Bacteria • Anglerfish have light emitting symbiotic bacteria in dorsal appendage

22. Archaea • General characteristics • small (0.1 to 15 micrometers) • prokaryotic • adapted to extreme environmental conditions: high and low temperatures, high salinities, low pH, and high pressure • formerly considered bacteria • differences from bacteria • cell walls lack special sugar-amino acid compounds in bacterial cell walls • cell membranes contain different • lipids, which help stabilize them • under extreme conditions Hydrothermal vents

23. Archaea • Nutritional Types • archaea includes photosynthesizers, chemosynthesizers and heterotrophs • most are methanogens: anaerobic organisms that metabolize organic matter for energy, producing methane as a waste product • halobacteria (photosynthetic), thrive at high salinities • Hyperthermophiles • organisms that can survive at temperatures exceeding 100o C, such as near deep-sea vents • Potential for biomedical and industrial application