Microbial mat

Wastage is caused by biological material accumulating on or near surfaces. Microbial mats such as slime layers and massive accumulations of larger organisms cause most damage. 

Sanchez-Cabeza JA, Masque P, Martinez-Alonso M, Mir J, Esteve I (1999) Pb-210 atmospheric flux and growth rates of a microbial mat from the northwestern Mediterranean Sea (Ebro River Delta). Environ Sci Technol 33 3711-3715... 

In many cases, microbial life in nature develops into zones within which communities are dominated by one or a few functional groups, such as aerobes, sulfate reducers, or methanogens. Distinct zoning is characteristic, for example, of microbial mats (Konhauser, 2007), hot springs (Fouke et al., 2003), marine sediments and freshwater muds (Berner, 1980), contaminated aquifers (Bekins et al., 1999), and pristine groundwater flows (Chapelle and Lovley, 1992). Communities develop as well in laboratory experiments, when microbes are cultivated in pure or mixed culture. 

For cells that occur under layers or inside colonies of scytonemin-producing taxa, the attentuation of UVA may be even more effective. The umbrella -function of scytonemin produced by surface layers of Lyngbya aestuarii in microbial mats for other cyanobacteria living underneath has already been described (Sect. 13.3.1) (Karsten et al. 1998a). 

Bebout BM, Garcia-Pichel F (1995) UV-B induced vertical migrations of cyanobacteria in a microbial mat. Appl Environ Microbiol 61 4215 4222... 

Fig. 2.127. HPLC-DAD chromatograms (300 - 800 nm) plotted at the maximum absorbance of microbial mat extracts from (a) the living cyanobacterail mat, (b) 8 - 10cm depth, (c) 10-12cm depth, and (d) 12 - 14 cm depth. Numbers refer to pigments in Table 2.101. Reprinted with permission from R. L. Airs et al. [292].

R.L. Airs and B.J. Keely, A high resolution study of the chlorophyll and bacteriochlorophyll pigment distributions in a calcite/gypsum microbial mat. Org. Geochem. 34 (2003) 539-551. 

Modem layered microbial communities provide a view into biochemical redox cycling. Oxidation of Fe(ll) through high O2 contents generated by cyanobacteria generally occurs in the top most (photic) portions of microbial mats. The upper, near-surface layers of microbial mats that are rich in cyanobacteria are commonly underlain by purple and green anoxygenic photosynthetic bacteria that thrive in the IR photic spectra (Stahl et al. 1985 Nicholson... 

Ghiorse WC (1989) Manganese and iron as physiological electron donors and acceptors in aerobic-anaerobic transition zones. In Microbial mats. Cohen Y, Rosenberg E (eds) ASM Press, Washington DC, p 163-179... 

Harder EC (1919) Iron-depositing bacteria and their geologic relations. US Geol Surv Prof Pap 113 Hartman H (1984) The evolution of photosynthesis and microbial mats a speculation on banded iron formations. In Microbial Mats Stromatolites. Cohen Y, Castenholz RW, Halvorson HO (eds) Alan Liss Pub, New York, p 451-453... 

Nicholson AM, Stolz JF, Pierson BK (1987) Structure of a microbial mat at Great Sippewissett Marsh, Cape Cod, Massachusetts. FEMS Microb Ecol 45 343-363... 

Nutrient pollution has contributed to other notable disturbances in the structure of marine food webs. These include (1) bioinvasions of macroalgae and microbial mats... 

Jannasch, H.W. Wirsen, C.O. (1981) Morphological survey of microbial mats near deep-sea thermal vents. Appl. Environ. Microbiol. 41 528-538... 

J. Am. Ceram. Soc. 82 1937-1940 Konhauser, K.O. Ferris, F.G. (1996) Diversity of iron and silica predpitation by microbial mats in hydrothermal waters, Iceland Implications for Precambrian iron formations. 

High water flow rates or excessive turbulence are factors that can limit the success of microbial mats. In a field-scale experiment, a 50-cm snowfall flow dramatically increased water flow rates in the mat pond, causing severe damage to the mat. As a result, the pond had to be drained and reinoculated. Snails and other invertebrate herbivores have also been known to damage the mats. 

Rosenberg, E., Rosenberg, M., Shoham, Y., Kaplan, N. Sar, N. (1989). Adhesion and desorption during growth of Acinetobacter calcoaceticus on hydrocarbons. In Microbial Mats, ed. Y. Cohen E. Rosenberg, pp. 218-26. Washington, DC ASM Publications. 

Similar to the microbial biofilm preparations described above, free-floating, viable microbial mats are also successful in removal of metals from solution (Bender Phillips, 1994 Vatcharapi jarn, Graves Bender, 1994). Consisting primarily of algae, cyanobacteria and bacteria, microbial mats perform a number of activities which promote metal complexation and subsequent removal. The mat contains oxidizing and reducing zones that aid in the immobilization and precipitation of... 

Microbial mat formation may also stimulate metal removal through sulfate reduction. Barnes, Scheeren Buisman (1994) have developed a process that specifically uses sulfate-reducing bacteria to treat metal-contaminated groundwater. In this process, as groundwater is pumped through the water treatment plant, sulfide produced by sulfate-reducing bacteria precipitates the metals in the water. Metal concentrations in the treated water were reportedly reduced to fig/l quantities and the water was suitable for release into the environment. 

Bender, J. Phillips, P. (1994). Implementation of microbial mats for bioremediation. In Emerging Technology for Bioremediation of Metals, ed. J. L. Means R. E. Hinchee, pp. 85-98. London Lewis Publishers. 

Finkelstein, D.B., Munhall, A., Pratt, L.M. and Bauer, C.E. (2004) A baseline study of evaporative water chemistry and microbial mat diversity from alkaline lakes in Warner Valley, Oregon. Abstracts with Programs. The Geological Society of America, 36(5), 87. 

Inskeep, W.P., Macur, R.E., Harrison, G. et al. (2004) Biomineralization of As(V)-hydrous ferric oxyhydroxide in microbial mats of an acid-sulfate-chloride geothermal spring, Yellowstone National Park. Geochimica et Cos-mochimica Acta, 68(15), 3141-55. 

Tazaki, K., Okrugin, V., Okuno, M. et al. (2003) Heavy Metallic Concentration in Microbial Mats Found at Hydrothermal Systems, Kamchatka, Russia. Science Reports of the Kanazawa University, Vol. 47, Issue 1-2, 1-48. 

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