Digital Characterization of Thrombolithe-stromatolite Reef in Carbonate Ramp System in Namibia 2005
Janet Seifert: What could a 'Whole Earth Stromatolite Catalogue' tell us?
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Transcript of Janet Seifert: What could a 'Whole Earth Stromatolite Catalogue' tell us?
Lithification
Precipitation by microbial processes and physiochemical characteristics is controlled by two factors:
Exopolymeric substances EPS
Saturation index (pH, {Ca2+} and {CO3
2-}
EPS matrix sequesters particulates which provides nutrients
Compounds aid in creating geochemical gradientsBinding and concentrating organic molecules and IonsClose to cells
EPS binds calcium carbonates.heterotrophic and sulfate reducers degrade the EPS
Favors the localized precipitation of calcium carbonate.
Whether or not a microbial mat becomes ‘lithified’, i.e. a stromatolite, depends upon the bacterial constituency and the environment.
As investigative targets, these biomes represent:
Long term, discreet microbial entities, tractable numbers.
Metabolic flux model targets, mesocosm experiment.
Confined to locations that do not allow natural predation to occur
Environmental dipsticks that span fresh and marine water systems.
Environmental harbingers (or canaries in the coal mine) of climactic, diversity tied to geography, and environmental change
Proposed as remnant of an ancient ocean… Souza, et al PNAS 2006
Low in P - Total P ranges between 0.05 - .4 uM, with most of the poza's in the .1 - .3 uM range
Galápagan-like – >120 endemic species
Contain living microbialites
16S sequence affiliation total and by valley
Total sample
Valleys samplesValle Ocampo Mina Reforma Cuatro Cienegas valle Hundido
Agricultural well subterranean superficial agricultural well
Souza et al., 2006
PNAS
50% of the clones
are affiliated with
marine microbes.
Stoichiometry, Redfield ratios, and ecological stoichiometry… branch of chemistry that deals with
the relative quantities of reactants and products in chemical reactions
C:N:P = 106:16:1
Elser and team link the elemental physiology of organisms to the their food web interactions and ecosystem function.
EXPERIMENTAL TEST
Summer 2009:
Add +PO4 (high or low) and/or Organic Carbon to Río Mezquites water; water exchanged and re-spiked daily
Examine ecosystem responses and changes to microbial biomass N:P
Short experiment (16 days)
Stoichiometric knife edge
Elser et al “there are in situ stoichiometric constraints at CC, the balance between the microbial community and the eukaryotic community are delicately balanced around an ecological stoichiometry.”
The problem with Phosphorus
From Kansas to China's Sichuan province, farmers treat their fields with phosphorus-rich fertilizer to increase the yield of their crops. What happens next, however, receives relatively little attention. Large amounts of this resource are lost from farm fields, through soil erosion and runoff, and down swirling toilets, through our urine and feces.
Stromatolites: Living
Laboratories Mya Breitbart (viral phylogeny,
metagenomics), David Hollander (Isotope geochemistry)
Valeria Souza (microbial population biology) Luis Eguiarte and the whole UNAM crew, CINVESTAV – Gabrielle Olmedo
Jim Elser (ASU) and all, freshwater limnology, stoichiometry
Abby Allwood (NASA), Shery Cady (Portland)
Brendan Burns (South Wales), Pam Reid (Miami)