microbes in various habitats Flashcards
what percentage of the water that covers the earth’s surface is marine water
96%
T or F: the majority of life in the ocean consists of microorganisms
true
there are ___ organisms/ml of water in the costal marine environment
10^8
list some physical factors that play a role in supporting microbial life in the ocean (5)
pH, temp, light penetration, amount of dissolved oxygen, pressure
list the 3 ocean zones
surface zone (photic zone)
dark mid-water zone
deep sea zone (aphotic zone)
how many meters deep is the surface zone
200m
how many meters deep is the deep water zone
+ 1000m
what microbes are located in the surface zone
photosynthetic microbes, and some heterotrophic bacteria/archaea
T or F: there is a tight recycling of nutrients in the surface zone
true
why is it good that there is tight recycling of nutrients in the surface zone
it aids in the survival of microbes (referred to as the microbial loop)
T or F: there is photosynthesis in the dark mid-water zone
false; there is no photosynthesis taking place
how do microbes obtain nutrients in the dark mid-water zone
marine snow
what is marine snow? give some examples of what it’s made of
organic matter produced in the upper level that’s hard to degrade and falls through the depths. Can be made of fecal pellets or diatom frustules
what happens to the microbes that colonize marine snow
they form a biofilm and work together to degrade the snow
what happens as biofilm microbes are degrading marine snow?
it attracts free swimming microbes which help to further degrade the snow
__% of the photosynthetically derived carbon reaches the ocean floor
1%
T or F: the ocean sediments are the earth’s largest microbial habitat
true
list 3 characteristics of microbes in the deep sea zone
barophilic, psychrophilic, grow very slowly
what domain of microbes were found in the mariana trench
bacteria
T or F: there are naturally occurring oil-eating microbes
true
give an example of a species of oil-eating microbes
Alcanivorax sp.
there are about __x more viruses in the ocean than bacteria and archaeons combined
10x
list 2 ways to quantitate marine viruses
electron microscopy, fluorescent microscopy
what percentage of viral genomes from the ocean have no match on any database
90%
list 3 roles of viruses in the ocean
major players in microbial mortality, play a role in supplying ecosystems with nutrients, play a role in HGT (transduction)
where is the largest fraction of freshwater on earth
frozen at the earth’s polar regions (glaciers)
which domain dominates the prokaryotic glacial ice community
bacteria
T or F: the bacterial communities isolated from glaciers are dormant
false; they are active
bacteria belonging to more than ___ different phyla have been identified in the soil
35
describe how there is life in the soil (how do soil bacteria get oxyegn)
soil may have pores within a thin film of water that accumulates. Bacteria utilize the oxygen that diffuses into that water
largest phylum of gram negative bacteria in the soil?
Proteobacteria
largest phylum of gram positive bacteria in the soil?
Actinobacteria
which phylum does genus streptomyces belong to
actinobacteria
the number of archaea in the soil depends on what?
carbon:nitrogen ratio
more ___ in the soil = more archaea in the soil
nitrogen
T or F: fungi are important members of the soil microbial community
true
list 2 things that viruses in the soil do
have been found to contain genes to degrade CHOs, they play a role in biogeochemical cycling
