Microbes Flashcards
What are the microbes in the oceans?
Phytoplankton/algae, fungi, protozoa, archaea, bacteria, viruses
What are the size ranges of marine microbes?
Viruses (0.01-0.2um), prokaryotes (bacteria/archaea) (0.1-1um), eukaryotes (algae/protozoa) (1-200um)
Where are prokaryotes in marine ecosystems found?
Eubacteria: throughout the water column/sediments
Archaea: extreme environments
What are the characteristics of prokaryotes
Single cells, no nucleus, comprise most of genetic diversity on earch, most groups identified by variation of DNA
What are the typical ocean concentrations of bacterial cell densities?
10^5-10^6/mL
Total 1.6*10^29 bacteria
What are some facts about bacteria?
90-95% heterotrophic, 70% living C in ocean, 20% turn over everyday
Why did it take so long for bacteria to be recognized?
Small size, not easily cultured
How were bacteria discovered?
Fluorescent dies to bind nucleic acids, epiluroescence microscopy and flow cytometry
What happens to the bacteria if they have a low natural mortality?
Consumed by other plankton (heterotropic plankton /flagellates/protozoans), lysed by viruses
What do heterotrophic marine bacteria eat?
Dissolved organic matter (phytoplankton exudates, excretory products, viral lysis of host cells, sloppy feeding by zooplankton and protozoans)
How are microbes important in the marine food web?
DOM consumption, nutrient remineralization, food source for micrograzers (ciliates, flagellates)
What is the microbial loop?
Works alongside the classic food chain which is used for maintaining the flux of carbon and energy in marine ecosystems, centers around DOM
What are marine viruses?
Have no metabolism, inject genetic material into host cell, most abundant life form in oceans, largest reservoir of genetic diversity
What are the typical concentrations of viruses in the oceans?
10^7-10^11/mL, 10^23 viral infections/s, more abundant in surface waters and nearshore
What are bacteriophages?
Viruses that infect heterotropic bacteria
