Transcript Microbes
Ch. 5
The Microbial World
Ch. 5
“There are 100 million times more bacteria in the ocean than
stars in the known universe, and there are a thousand times
more viruses than bacteria. Yet we know little about the
relationships between microbes and their environment because
only one tenth of one percent of the bacteria have ever been
cultured.”
We don’t know much
• Venter’s team has found evidence of so many new microbial
species that the researchers want to redraw the tree of
microbial life... [They] identified more than 400 microbial
species new to science...
• One 10-month expedition (in 2007) that sampled the ocean
at just 41 locations returned with hundreds of new species
able to make millions of proteins that were previously
unknown, including tens of thousands that were thought to
occur only in higher, multicelled organisms. And this is from
only a tiny part of the ocean. Clearly, the microbial web is
almost unknown. A vast new frontier of life awaits
discovery.
The marine organism that supports all
others
• They make up 98% of the biomass of the world’s
oceans
• supply more than half the world’s oxygen
• major processors of the world's greenhouse gases
• About 1.5 million species have been names
• Tens of millions of more species may exist
• they may hold a cure for cancer and the solutions for
combating known diseases
• we know more about distant stars and planets than we
do about the microbes living in our oceans.
Viruses: Living or Non-living?
• On the threshold
somewhere in between
• Do not contain cells
– Consist of short chain of
genetic material
• Parasites
• Can only reproduce by
using other cells
machinery
Prokaryotes are large dots, viruses are small
dots. Viruses significantly outnumber the
prokaryotes.
So many viruses . . .
• Most abundant life-like particles in the ocean
...ocean waters contain about ∼ 4 × 1030 viruses. Because a marine virus contains about
0.2 fg (femtogram, or 1 quadrillionth) of carbon and is about 100 nm long, this translates
into 200 Mt (megaton, 1 million tons) of carbon in marine viruses. If the viruses were
stretched end to end they would span ∼ 10 million light years (1 light year = 9.5 trillion
km). In context, this is equivalent to the carbon in ∼ 75 million blue whales (∼ 10%
carbon, by weight), and is ∼ 100 times the distance across our own galaxy. – Suttle, C. A.
(2005).
Why are viruses important in the marine
environment?
Importance of Viruses
• Infect phytoplankton and
bacteria, causing them to
burst.
• Bursting cells release
contents – dissolved
organic matter (DOM)
• Fuels bacteria and
microbe growth
• Microbes eaten by
zooplankton, which are
eaten by larger
zooplankton, and so on,
up the food chain
Anti-aging?
• The Emiliania huxleyi virus 86,
attaches to marine algae
• "For an invading virus, the ability
to control when your host will
die and ensure your own survival
is quite incredible. Essentially the
virus hijacks the cell and slows
down the ageing process by
keeping it healthy for as long as
possible. It uses the cell as a kind
of factory to replicate itself and
eventually takes over completely,
killing off the cell."
Prokaryotes
• Smallest and simplest
true living organisms
• Oldest forms of life on
earth
• No nucleus or most
other organelles
– One exception is the
ribosome
• Bacteria and Archaea
Bacteria: Friend or Foe?
• Prokaryotes
• The most diverse domain
on the planet
– found from the beaches to
the deepest trenches
• Vital to life on earth
– Microbial loop
– Flow of energy from
phytoplankton DOM
bacteria protozoans
zooplankton.
Also the cause of diseases
and the spoilage of fish and
other food
Cyanobacteria
• Photosynthetic bacteria
• 1st photosynthetic
organisms on earth
– 3 billion years ago
• Major player in creating
the earth’s oxygen
atmosphere
Archaea
• Simplest, most primitive
forms of life
• 3.8 billion years old
• Love extreme
environments
– Hot sulfur springs, saline
lakes, highly acidic or
alkaline environments,
deep sea vents
• Found in common
marine environment as
well
Archaea
• Samples from the South
Pacific Ocean
– Rare at surface
– increased significantly
below depths of 250 m
– Below 1000 m, just as
common as bacteria
• One of the most
abundant life forms on
earth
– Sargasso Sea alone: at least
1,800 new species, possibly
50,000!
Protista
•
•
•
•
•
Single celled organisms
eukaryotic
Animal and plant like
Brown algae
Giardia (lovely germ
that causes diarrhea)
Diatoms
• Protists
• Enclosed by glass-like walls made of
silica
• Important primary producers in
cold waters
• Glassy shells of diatoms settle on
ocean floor, form diatomaceous
ooze.
– Diatomaceous earth used in
filters for pools, for clarifying
beer, and temp and sound
insulators, absorbents (toxic
spills) and as abrasives in
toothpaste
Diatoms and Oil?
• Diatoms produce oil (for
chemical energy and helps
them float)
• Diatoms die, settle to bottom
of ocean
• Turns into thick sludge,
kilometers thick
• Over 1000’s of years,
sludgeremains becomes buried
by sediments turns into
solid rock
• Chemical reactions, high heat
& intense pressure turn sludge
into oil!
• Then what?
How oil gets to your gas tank
Klaus Kemp’s Diatom Art
Diatom coke bottle?
Dinoflagellates
• Have two unequal
flagella
• Important primary
producers in warm
water.
Bay of Fire
• Bahia Fosforescente,
Puerto Rico
• Bioluninescent
dinoflagellates
• Pyrodinium bahamense
• Regulated by activity of
an enzyme, luciferase, on
proteins
• A shock response to
movement
La Jolla cove, CA
Protozoans
• Animal like protists
• Eukaryotic and
unicellular
• Foraminiferans
– Calcium carbonate shell
– Thin long strands used
to capture food
– The skeletons of
Homotrema rubrum
(the red foram), cause
the pink sands on
Bermudas beaches.
Protozoans: Radiolorans
• Shells are made
primarily of glass
• Most are microscopic
but can form chains up
to 9 ft in length!
Protozoans: Ciliates
• Have hair-like structure
called cilia
• Common ciliate is the
paramecium
Fungi
• Eukaryotic
• Mostly multicellular
– Molds and yeasts are
unicellular
• Major decomposers
– Especially in mangrove
forests
• Live in symbiotic
relations ship with
cyanobacteria—this
forms lichens