In situ nitrogen (C2H2) fixation in lakes of southern Victoria Land, Antarctica

Allnutt, F. C. Thomas; Parker, Barry; Seaburg, Kenneth G.; Simmons, George M.

doi:10.1007/bf02255169

Cited by 31 publications

(10 citation statements)

References 28 publications

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“…Seaburg et al (1981) found that nineteen algal isolates from southern Victoria Land streams grew from 2 to lS^C with optimal temperatures for growth likely to be towards the high end of this range, well above ambient. These algae appear to have no unusually rapid growth characteristics at low temperature (Seaburg et al, 1981) and will therefore metabolize slowly in the cold stream environment.…”

Section: Discussionmentioning

confidence: 98%

“…This temperature responsiveness may not simply be a cyanophyte feature however. The four Antarctic algal isolates (all chlorophytes) studied in detail by Seaburg et al (1981) in unialgal clonal culture all had strongly depressed growth rates near 0°C and growth optima about ICC. Near-zero stream temperatures must strictly limit the in situ growth rates of the Antarctic epilithon.…”

Section: Discussionmentioning

confidence: 99%

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Antarctic stream ecosystems: physiological ecology of a blue‐green algal epilithon

1986

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1. Several dozen summer meltwater streams are located in the McMurdo Sound region (c. IS^S 165°E) of southern Victoria Land. They are characterized by a highly variable flow regime at diel, seasonal and annual timescales; wide fluctuations in temperature and nutrient content; and a very simple epilithic community of cyanophytes {Nosloc spp., Oscillatoriaceae),. bacteria, fungi and microherbivores.2. The epilithon survives the dark Antarctic winter as dry, frozen mats which provide a large inoculum for growth the following summer. This overwintering assemblage retains a high metabolic capacity and responds rapidly to rehydration.3. In a series of artificial substrate experiments, biomass accumulation rates were generally less than 0.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Antarctic stream ecosystems: physiological ecology of a blue‐green algal epilithon

1986

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“…Gloeocapsa sp.). Allnut et al (1981) surveyed Nz-fixation by benthic and moist cyanobacterial mats in Dry Valley, the inflow and outflow of streams and adjacent soils. They observed measurable levels of fixation by the algal mats experienced sufficient moisture, light, temperature and low concentrations of ammonium ions.…”

Section: Discussionmentioning

confidence: 99%

Nutrient status, algal and cyanobacterial flora of six fresh water streams of Schirmacher Oasis, Antarctica

1995

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The algal and cyanobacterial flora and the chemical environment of six freshwater streams of Schirmacher Oasis, Antarctica were investigated. Over 30 species of algae, predominantly cyanobacteria (Cyanophyceae), were recorded. Nz-fixing species, both heterocystous and unicellular diazotrophs, contributed more than 50% to the counts and their dominance was greatest in the middle of the stream where nitrogen and other nutrients were low. Green algae and diatoms also contributed to the flora. The species composition varied between streams. Glacial and snow drift meltwater streams contained a distinctive community. Based on diversity indices, these streams could be classified into two clusters.

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“…Tolypothrix tenuis in Sombre Lake) activity is extremely low (Dr A Wootton, unpublished data). Even in continental lakes, only Nostoc spp (Nostoc commune) appear to be nitrogen fixers and these are largely restricted to the lake shallows (Allnutt et al, 1981). The absence of significant amounts of available P in most lakes will clearly increase the N:P ratio and therefore make N-fixation somewhat unnecessary but nitrogen fixation is also very temperature-dependent and, in the Antarctic aquatic environment, it would appear that constant low temperatures reduce fixation to insignificant levels, in terms of the overall N budget, except in shallow situations where local solar heating occurs.…”

Section: Benthic Cyanophyceaementioning

confidence: 99%

Microbial diversity and function in Antarctic freshwater ecosystems

Ellis‐Evans

1996

Biodivers Conserv

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Freshwater lakes occur through much of Antarctica and are characterized by short food chains dominated by microbes. Comparatively few studies have been made of continental freshwater lakes until recently, with the main emphasis being on the less extreme maritime Antarctic lakes. The wide range of trophic status seen at the northern extremes of the maritime Antarctic reduces markedly further south, but a wide range of micro-organisms occur throughout the latitudinal range. Information on seasonal and spatial patterns of microbial activity for freshwater lakes demonstrate rapid changes in community composition at certain times of year despite constant low temperatures. Benthic communities of cyanobacteria and bacteria are a feature of most lakes and are involved in a wide range of geochemical cycling. There is a need for more detailed taxonomic information on most groups and considerable potential for molecular studies.

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In situ nitrogen (C2H2) fixation in lakes of southern Victoria Land, Antarctica

Cited by 31 publications

References 28 publications

Antarctic stream ecosystems: physiological ecology of a blue‐green algal epilithon

Antarctic stream ecosystems: physiological ecology of a blue‐green algal epilithon

Nutrient status, algal and cyanobacterial flora of six fresh water streams of Schirmacher Oasis, Antarctica

Microbial diversity and function in Antarctic freshwater ecosystems

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