MicrobesPresented by

Jessica Susser, Amol Mehta, Brittany Ham, Sidra Jocus,

Liana Harotian

A microbe is defined as any microscopic organism(otherwise known as microorganisms)

What are microbes?

Examples: Bacteria, Archaea, Viruses, small parasites

Important microbes of the deep:

BACTERIA

What are Bacteria?Bacteria are single-cell prokaryotes,

meaning they lack a nucleus and membrane-bound organelles.

Depending on their species, they can be aerobic (requiring oxygen) or anaerobic

Where are Bacteria found in the oceans?

Everywhere!All throughout the ocean, in every water

column.

Some live independently, while others form symbiotic relationships with other organisms.

Cyanobacteria (blue-green algae)Photosynthetic

Greek: “kyanós” meaning blue

Fossils as old as 3.5 mya

Found in extreme environments (high salinity areas, deep

sea vents, etc)

Cyanobacteria: Continued

They account for ~ 25% of Earth’s photosynthetic productionTheir electronic activity is

an important pathway for

conversion of solar energy into chemical

energy

They can include unicellular or

colonial species

Cyanobacteria and Ocean Acidification

Genus Trichodesmiumincreased photosynthetic rates under elevated

CO2 conditions

Bloom-forming Nodularia decreased cellular division rates under elevated

CO2 conditions

Possible explanation for difference: Different ecological strategy of the two bacteria

Nitrogen Cycling

– Nitrogen fixation: Atmospheric N2 (cannot be used by most organisms) is made into NH3 by nitrogen fixing organisms (including bacteria).

– Nitrofication: Ammonium (NH4+) is made when an organism dies and is decomposed by decomposers (mostly fungi and bacteria). The Ammonium is the converted into nitrate (NO3-) by “nitrifying” bacteria and can be used by plants and other organisms.

• Nitrogen is vital to all forms of life

– Denitrofication: Nitrate is converted into atmospheric N2 by “denitrifying bacteria.” This N2 cannot be used by organisms until it is fixated by nitrogen fixating bacteria.

Nitrogen moves throughout the atmosphere through the Nitrogen Cycle:

• Oceans cycle a lot of Nitrogen; they cycle the most of any location on Earth.

Some Cyanobacteria fixate nitrogen

• Nitrogen fixation can only take place in anoxic (without oxygen) conditions, so many nitrogen-fixating bacteria live in

sediments, fixate nitrogen at night, or have developed symbiotic relationships with marine organisms

Symbiotic RelationshipsMany nitrogen-fixing bacteria have symbiotic relationships with diatoms (unicellular,

photosynthesizing organisms), and these bacteria contribute significantly to global

nitrogen fixation

Some nitrogen-fixing Cyanobacteria live in coral-reefs and have symbiotic relationships with the coral. Nitrogen fixing and nitrifying

bacteria also live in sponges.

Symbiotic bacteria inside microscopic life forms called diatoms take nitrogen from the air, enabling them to thrive in the nutrient-poor tropical Atlantic Ocean.

Credit: David Caron

US National Science Foundation

• Nitrogen-fixing Cynobacteria may increase the rate of Nitrogen-fixation at higher concentrations of CO2. This may help to offset global warming because it

would stimulate growth of photosynthetic organisms which take in

CO2.

ARCHAEAGenetically and biochemically different from

bacteria

Methane producers

Very small; usually less than one micron long (1/1000 of a meter)

Discovered in 1970’s by Dr. Carl Woese and his colleagues at the

University of Illinois while studying relationships among prokaryotes

Four groups of Archaea

•Methanogens

•Extreme halophiles

•Sulfate-reducing archaea

•Extreme thermophiles

Archaea Environment:

Extreme living conditionsHydrothermal vents in deep ocean (methanogens,

sulfate reducers, and extreme thermophiles)

Hot springs (methanogens, sulfate reducers, and extreme thermophiles)

Highly saline land-locked seas (halophiles)

Extremely alkaline or acid waters

Anoxic muds in marshes or at the bottom of the ocean (methanogens)

Deep underground petroleum deposits

However...

New research shows that archaeans do not only live in extreme environments, but are also

abundant in plankton in the open sea, as well as coral in coastal marine environments

Example of Archaea: Halobacterium

They live in extremely saline waters

They contain pigment (bacteriorhodopsin) that gives the archaea its color and provides it with chemical energy (similar to a pigment found in

our retinae)

Effects of ocean acidification:

Archaea might actually benefit from ocean acidification because they can survive in highly acidic

waterHowever, those archaeans which are found in plankton and coral may be negatively affected by the decline of

plankton and coral populations due to acidification

• Czerny, J., Barcelos e Ramos, J., & Riebesell, U., 2009. Influence of elevated CO2 concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium Nodularia spumigena. Biogeosciences 6(9): 1865-1875

• DeLong, E.F. “Archaea in Coastal Marine Environments.” Proceedings of the National Academy of Sciences of the United States of America (PNAS). 89 (1992): 5685-5689. Boston University Library 27 September 2010 <http://www.pnas.org/content/89/12/5685.short>.

• Hutchins, D.A. et al. 2007. CO2 control of Trichodesmium N2 fixation, photosynthesis, growth rates, and el- emental ratios: implications for past, present, and future ocean biogeochemistry. Limnol. Oceanogr. 52:1293–1304.

• Introduction to the Archaea. Ben Waggoner and B.R. Speer. 1994-2006. University of California Museum of Paleontology. 27 September 2010 <http://www.ucmp.berkeley.edu/archaea/archaea.html>.

• Flore, Clara L. Jarret, Jessica K. Olson, Nathan D. Lesser, Michael P. “Nitrogen fixation and nitrogen transmormations in marine symbioses. Trends in Microbiology. 2010.

• Guinotte, J. M. and Fabry, V. J. (2008), Ocean Acidification and Its Potential Effects on Marine Ecosystems. Annals of the New York Academy of Sciences, 1134: 320–342. doi: 10.1196/

• "Microbes in the Ocean - Sea, Oceans, Effects, Temperature, Important, Types, Plants, Source, Marine, Oxygen, Human, Pacific." Water: Science and Issues. Web. 29 Sept. 2010. <http://www.waterencyclopedia.com/Mi-Oc/Microbes-

Works Cited• Berman-Frank, Llana; Lundgren, Pernilla; Chen, Yi-Bu; Kupper, Hendrik;

Kolber, Zbigniew; Bergman, Brigitta; Falkowski, Paul. “Segregation of Nitrogen Fixation and Oxygenic Photosynthesis in Marine Cyanobacterium Trichodesmium.”

• Molles, Manuel C. Ecology Concepts and Applications Fifth Edition. Boston: McGraw Hill, 2010.

•

Wegley, Linda, Yanan Yu, Mya Breitbart, VeronicaCasas, David I. Kline, Forest Rohwer. “Coral-associated Archaea.” Marine Ecology Progress Series 273 (2004): 89-96. <http://www.marine.usf.edu/genomics/PDFs%20of%20papers/wegleyetal2004.pdf>.