Transcript Microbial Ecology or Whose Planet Is This, Anyway?

Whose Planet Is This, Anyway?
Elio Schaechter
Dr. Saier’s Class
Sept. 28, 2011
Google Blog
“Small Things Considered”
Microbes:
•Are the source of all other life forms
•Are much more diverse than plants and
animals
•Are enormously abundant,
about 50% of the total biomass
•Grow in virtually everywhere on earth
where there is liquid water
Number of People on Earth:
6.5 followed by 8 zeroes
6,500,000,000
Number of Bacteria On Earth:
about 10 followed by 30 zeroes
10,000,000,000,000,000,000,000,000,000,000
There are about 3 Tons of Bacteria
for Every Human Being on Earth!
The elephant’s weight is that of
the bacteria per human being
What would happen if all microbes on Earth
went on strike?
•Plants would run out of usable nitrogen in about one week
•Plants would run out of CO2 in about a year
•We’d start to run out of food in less than a year
•We’d gradually lose the oxygen in the air
•Our climate would change drastically (in ways difficult to
predict)
The White Cliffs of Dover
Microbial mats the size of Alabama
In 1998, Thomas Gold, wrote a highly influential book, The Deep Hot Biosphere.
•there is abundant microbial life in the water
within the pores, cracks and fissures of the rocks beneath our feet.
• hydrocarbons were not derived from fossils but rather were
created early in the life of the planet by chemical and physical
processes below the crust, including radiation.
How to study this: begin at a deep hole in the ground,
such as a gold mine several kilometers deep. Drill for water,
discard the first few day’s flow.
Find ~ 3-4 104 bact/ml. Oxidize H, reduce sulfate
Desulfotomaculum predomintes (10% of spores survive 15 min at 140° C)
Li-Hung Lin et al (Int’l consortium). Science, 2006
Single cells in populations
– substrate tracking autoradiography
fluorescence in situ hybridization
(STARFISH) simultaneously detects
specific cell types via 16S rRNA probe
and activity via microautoradiography
Single cells in isolation
– •nano-cell biology
ultrahigh resolution fluorescence
microscopy + quantum dots, electro
cryo-tomography, Raman
spectroscopy + metallic
nanoparticle-FRET
•single cell genome sequencing
Short Break
Microbes Influence
the Weather
Everybody is always talking about the weather
Negative feedback loop: the more DMS is made,
the more clouds are formed, the less sunlight shines
on the ocean, the less photosynthesis is carried out,
the less DMSP is made, the less DMS is produced, etc.
Todd JD et al. Science 2007
DMSP=dimethylsulfoniopropionate
A few more cheerful facts about DMSP and DMS
•Some large seaweeds also make DMSP and have DMSP lyase
•DMS and acrylate may deter grazing by herbivores
(zooplankton grazers prefer algae without DMSP-lyase)
Zooplankton, including krill, feed on phytoplankton blooms,
releasing DMSP, which becomes DMS. Higher DMS above
the ocean is an indication of zooplankton. Seabirds are also
seen in areas with high DMS. Do they smell it? Is DMS a
foraging clue?
(Releasing DMS in the air or on slicks
attracts some species of petrels and others)
Extremophiles
Bacteria Of Boiling Hot Springs In Yellowstone National Park
Photosynthetic bacteria and
lichens in Antarctic sandstone
Algae in silica granule
from Yellowstone (pH
1.0)
The reactor at Chernobyl
The “Chernobyl mold”
This fungus grows better with radiation
SYMBIOSES
Prokaryotic symbiosis
Red:archaea (CH4 + 2 H2O  CO2 + 4 H2)
Green; bacteria (5 H2 + SO42-  H2S + 4 H2O)
Deep sea
Hydrothermal
vents
•
BIOFILMS
•
VIRUSES
Abundance of Organisms in 1 mL of Seawater
Zooplankton
<<1
Phytoplankton
Algae
3,000
Protozoa
Photosynthetic
4,000
Bacteria
Heterotrophic Bacteria
V i r u s e s/ Phage
100,000
1 ,000,000
10,000,000
Ecological Roles of Marine Phage
• Most common predator in the ocean
~107 phage ml -1 vs. ~10 -19 great white sharks ml-1
• Major players in global C and nutrient cycles
• Transduction and lysogenic conversion
- 1025-1028 base pairs of DNA per year in the oceans
- Vibrio cholerae
Culture based studies are limited because >99%
of the marine bacterial hosts are not readily
cultured
Forest Rohwer
this is equivalent in weight
to 75 million blue whales!
wow!
Curtis A. Suttle
One teaspoonful of ocean
water contains about one
million bacteria
The total amounts to the
weight of about 100 million
Blue Whales!
Thanks for Listening