Marine Microbes

What is a Microbe? All three domains: Unicellular Important as: –Primary producers –Consumers –Pathogens –Symbionts –Sediment producers

Marine Viruses Total dependence on host 10x more abundant than prokaryotes Infectious agents of all marine life

Bacteria Spheres, rods, and other shapes Heterotrophic and autotrophic Important groups: –Decay bacteria –Cyanobacteria (“Blue-green algae”) Why “blue-green”? Where can we find it?

Archaea Similar shapes to bacteria Small ( um) Prokaryotic Hetero and autotrophic So why aren’t they bacteria?

Living on the Edge! Hypersaline lakes Hydrothermal vents Deep muds (anoxic) High acidity/alkalinity

But not always!

Prokaryote Metabolism  Autotrophy - Organic carbon produced  Photoautotrophy  Chemoautotrophy  Heterotrophy - Followed by respiration  Anaerobic  Aerobic  Nitrogen fixation  Autotrophy - Organic carbon produced  Photoautotrophy  Chemoautotrophy  Heterotrophy - Followed by respiration  Anaerobic  Aerobic  Nitrogen fixation

The Problem with Protista Extreme Diversity Single and multicellular Major size variations “Plant-like” protists act like animals and vice versa Structural diversity within groups Different evolutionary histories But where else do you put them???

Protozoans (“Animal-like”) Very diverse, though all eukaryotic and unicellular (some colonial) Heterotrophic (some photosynthesize also) Foraminiferans, Radiolarians, and Ciliates

Foraminiferans “Forams” Bottom dwellers CaCO 3 test w/ pseudopodia Biogenous sediments (limestone, chalk)

Radiolarians Planktonic Silicate test w/ pseudopodia Biogenous sediments (silica, glass)

Algae (“Plant-like”) Unicellular and multicellular Photosynthetic (some heterotrophy) Color determined by pigments in chloroplasts

Why aren’t they plants? Lack specialized structures (leaves, roots, stems, etc.) Some have animal-like traits (free swimming, heterotrophy) Simple reproductive structures

Diatoms Unicellular Mostly planktonic Primary producers in polar and temperate regions Chlorophyll a & c, Carotenoids Silica cell walls

Dinoflagellates Planktonic producers (some hetero and parasitic) 2 flagella, cellulose cell wall Zooxanthellae Bioluminescence

Harmful Algal Blooms (HABs) Seasonal blooms normal Usually dinoflagellates Eutrophication Why are they harmful? –Organism death due to toxins, O 2 depletion, gill damage, etc. –Toxins stored in tissues (ex. PSP)