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Topic: Oligotroph

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	Oligotrophic Summary
		The term oligotrophic is derived from the Greek term meaning "poorly nourished" and refers to an aquatic system that has low overall levels of primary production, principally because of low concentrations of the nutrients that plants require.
		Oligotrophic environments are of special interest for the alternative energy sources and survival strategies life could rely upon.
		An example of oligotrophic soils are those on white-sands, with soil pH lower than 5.0, on the Rio Negro basin on northern Amazonia that house very low-diversity, extremely fragile forests and savannahs drained by flwater rivers.
	www.bookrags.com /Oligotrophic (304 words)

	JGI Sphingopyxis alaskensis RB2256 Home
		In this oligotrophic environment, prokaryotes dominate in terms of biomass and play an essential role in regulating the accumulation, export, re-mineralisation and transformation of the world's largest pool of organic carbon.
		These studies have shown that its capacity to thrive in oligotrophic environments is linked to unique genetic and physiological properties which are fundamentally different from those of the well studied bacteria such as Escherichia coli.
		Characteristics that promote S. alaskensis as a model oligotroph include a constant ultramicro-size (<0.1 µm 3), irrespective of whether it is growing or starved, that provides it with a mechanism for avoiding predation, and a high surface to volume ratio to enhance nutrient uptake.
	genome.jgi-psf.org /draft_microbes/sphal/sphal.home.html (803 words)

	Title page for ETD etd-07072006-112747
		Oligotrophic bacteria can metabolize, divide and grow when carbon concentrations are in the parts per million (mg/L) range.
		Oligotrophs have been isolated from marine, freshwater, soil, clinical and indoor environments, yet understanding the factors controlling of their distributions remains unclear.
		Oligotrophic bacteria isolated during the distributional study were monitored for growth in four broths with carbon contents that ranged logarithmically from 12-12,000 mg/L. Unexpectedly, most isolates grew optimally in the broth highest in nutrients, and approximately equal numbers of bacteria were found to grow optimally in the two media with mid-range nutrient concentrations.
	etd.lib.ttu.edu /theses/available/etd-07072006-112747 (388 words)

	BABS - Extremophiles: Marine Oligotrophic Ultramicrobacteria
		alaskensis as a model oligotroph include a constant ultramicro-size (<0.1 µm³), irrespective of whether it is growing or starved, that provides it with a mechanism for avoiding predation, and a high surface to volume ratio to enhance nutrient uptake.
		In particular, we have shown (see publications) that its capacity to thrive in oligotrophic environments is linked to unique genetic and physiological properties.
		The properties of this model oligotroph are fundamentally different to those of the well studied bacteria such as Escherichia coli or marine Vibrio species.
	www.babs.unsw.edu.au /research/ehm/lab_cavicchioli_oligotrophic.html (711 words)

	DIALOG Dissertation Abstracts (Site not responding. Last check: 2007-10-11)
		Spatial and temporal variability of the silicon cycle in diverse oligotroph and mesotroph systems.
		The silicon biogeochemical cycle was studied in diverse coastal and oceanic systems, oligotroph to mesotroph, in the Mediterranean Sea (SOFi, ALMOFRONT II and PROSOPE campains), in the North East Atlantic (POMME campaign) and in the HNLCLSi area of the Indian sector of the Southern Ocean (ANTARES 4 campaign).
		This work has evidenced the role of the availability of dissolved Si upon diatom distribution in the western Mediterranean, where silicic acid stocks can be inferior to nitrate stocks.
	aslo.org /phd/dialog/200210-9.html (456 words)

	Implications of rRNA Operon Copy Number and Ribosome Content in the Marine Oligotrophic Ultramicrobacterium ...
		of an obligate oligotroph to grow on rich media (34).
		Although the defining characteristics of an oligotroph are the subject of debate (23, 34), we operationally define RB2256
		Fegatella, F., Cavicchioli, R. Physiological Responses to Starvation in the Marine Oligotrophic Ultramicrobacterium Sphingomonas sp.
	aem.asm.org /cgi/content/full/64/11/4433 (5260 words)

	Trophiesystem - Wikipedia
		Oligotroph sind Gewässer mit wenig Nährstoffen und daher geringer organischer Produktion.
		Die geringe Phosphatzufuhr begrenzt das Pflanzen- und Algenwachstum; in sauerstoffreichem Wasser enthaltene freie dreiwertige Eisenionen fällen Phosphat und entziehen es so dem Stoffkreislauf (Phosphatfalle).
		Oligotrophe Gewässer haben oft grobkörnige Uferstrukturen mit geringem Pflanzenbewuchs.
	de.wikipedia.org /wiki/Oligotroph (549 words)

	Space Studies Board
		On small solar system bodies with limited concentrations of organics (see, e.g., McCord et al., 1997), these compounds could be used by oligotrophs.
		In terrestrial settings, oligotrophic organisms typically grow on organic carbon at concentrations of 1 to 15 micrograms per liter (Morgan and Dow, 1986), and marine organisms have been shown to assimilate dissolved amino acids at concentrations of a few micrograms per liter or less (Wheeler et al., 1974).
		Chemolithoautotrophs (organisms that use inorganic forms of energy and carbon) could be the dominant microbial forms in some extraterrestrial environments.
	www7.nationalacademies.org /ssb/sssbch1.html (6836 words)

	Cycling of DOC and DON by novel heterotrophic and photoheterotrophic bacteria in the ocean (Site not responding. Last check: 2007-10-11)
		The hypothesis being tested is that SAR11 is an oligotroph and uses low molecular weight (LMW) compounds, whereas biopolymers and other high molecular weight (HMW) material are used mainly by Cytophaga-like bacteria.
		The biogeochemical significance of photoheterotrophic bacteria remains to be established, and although cyanobacteria are well known to be important in primary production, their contribution to DOM uptake is not clear.
		Nitrate and phosphate-rich freshwater (derived from anthropogenic activities) floats on the saline oligotrophic
	www.science.doe.gov /ober/CCRD/omp.html (1761 words)

	Lake OHRID Sub-basin (Site not responding. Last check: 2007-10-11)
		Numerous pressures on fisheries (over-harvested), the littoral zones (losses in the native reed zone) and the oligotroph water quality (eutrophication and fecal contamination due to communes like Pogradec on Albanian side and agriculture; the FYR Macedonian Ohrid bay has a sewage collection) have started to alter the sensitive character and uniqueness of the lake.
		The participants in the LOCP have begun to recognize the value of a clearly articulated “lake vision” (October 2002) to guide the development of an Action Plan.
		This vision is to clearly articulate the desire to conserve the ancient oligotroph character of the lake and to stimulate sustainable economic growth based on domestic and international tourism.
	www.inweb.gr /workshops/sub_basins/18_Ohrid.html (3017 words)

	The important lake (Site not responding. Last check: 2007-10-11)
		· Most of the north Swedish forest lakes are oligotroph, i.e.
		They are often surrounded by coniferous forest (spruce and pine) and have are filled from poor forest soil.
		More information about this can be obtained from Tornedalen Angling Club or from Övertorneå/Ylitornio Tourist information office.
	www.kattila.info /infopunkter/fiske/eng/sjon.htm (123 words)

	Lindeman-Trophic
		With increasing influx of nutritives from the surrounding drainage basin and increasing primary productivity (L1) oligotrophy is gradually changed through mesotrophy to eutrophy, in which condition the production of organic matter (L1) exceeds that which can be oxidized (L1') by respiration, predation and bacterial decomposition.
		The oxygen supply of the hypolimnion becomes depleted, with disastrous effects on the oligotroph-
		Organisms especially adapted to endure temporary anaerobiosis replace the oligotrophic species, accompanied by anaerobic bacteria which during the stagnation period cause reduction rather than oxidation of the organic detritus.
	oz.plymouth.edu /~lts/ecology/lindeman42.html (7940 words)

	Chart of Extremophiles
		Can develop at first cultivation on media containing minimal organic material (1 to 15 micrograms carbon per liter) and grow on such media in subsequent cultivation
		Requires nutrients at levels 100 times those of oligotrophs
		Microbes are far more likely than multicellular organisms to retain viability on small solar system bodies because they can adapt to a much wider range of environmental conditions.
	www.resa.net /nasa/extreme_chart.htm (861 words)

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