scholarly journals How are Antarctic planktonic microbial food webs and algal blooms affected by melting of sea ice? Microcosm simulations

1999 ◽  
Vol 20 ◽  
pp. 183-201 ◽  
Author(s):  
HC Giesenhagen ◽  
AE Detmer ◽  
J de Wall ◽  
A Weber ◽  
RR Gradinger ◽  
...  
Keyword(s):  
Sea Ice ◽  
Food Webs ◽  
Algal Blooms ◽  
Microbial Food Webs

Microbial Food Webs in an Artificially Divided Acidic Bog Lake

1998 ◽  
Vol 83 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Karel Šimek ◽  
Dieter Babenzien ◽  
Thomas Bittl ◽  
Rainer Koschel ◽  
Miroslav Macek ◽  
...  
Keyword(s):  
Food Webs ◽  
Microbial Food Webs

scholarly journals Simple models combining competition, defence and resource availability have broad implications in pelagic microbial food webs

2018 ◽  
Vol 21 (9) ◽  
pp. 1440-1452 ◽  
Author(s):  
Selina Våge ◽  
Gunnar Bratbak ◽  
Jorun Egge ◽  
Mikal Heldal ◽  
Aud Larsen ◽  
...  
Keyword(s):  
Food Webs ◽  
Resource Availability ◽  
Microbial Food Webs ◽  
Simple Models

scholarly journals Microbial food web dynamics along a soil chronosequence of a glacier forefield

2011 ◽  
Vol 8 (11) ◽  
pp. 3283-3294 ◽  
Author(s):  
J. Esperschütz ◽  
A. Pérez-de-Mora ◽  
K. Schreiner ◽  
G. Welzl ◽  
F. Buegger ◽  
...  
Keyword(s):  
Food Web ◽  
Microbial Communities ◽  
Food Webs ◽  
Litter Decomposition ◽  
Developmental Stages ◽  
Food Web Dynamics ◽  
Glacier Forefield ◽  
Microbial Food Webs ◽  
And Function ◽  
The 19Th Century

Abstract. Microbial food webs are critical for efficient nutrient turnover providing the basis for functional and stable ecosystems. However, the successional development of such microbial food webs and their role in "young" ecosystems is unclear. Due to a continuous glacier retreat since the middle of the 19th century, glacier forefields have expanded offering an excellent opportunity to study food web dynamics in soils at different developmental stages. In the present study, litter degradation and the corresponding C fluxes into microbial communities were investigated along the forefield of the Damma glacier (Switzerland). 13C-enriched litter of the pioneering plant Leucanthemopsis alpina (L.) Heywood was incorporated into the soil at sites that have been free from ice for approximately 10, 60, 100 and more than 700 years. The structure and function of microbial communities were identified by 13C analysis of phospholipid fatty acids (PLFA) and phospholipid ether lipids (PLEL). Results showed increasing microbial diversity and biomass, and enhanced proliferation of bacterial groups as ecosystem development progressed. Initially, litter decomposition proceeded faster at the more developed sites, but at the end of the experiment loss of litter mass was similar at all sites, once the more easily-degradable litter fraction was processed. As a result incorporation of 13C into microbial biomass was more evident during the first weeks of litter decomposition. 13C enrichments of both PLEL and PLFA biomarkers following litter incorporation were observed at all sites, suggesting similar microbial foodwebs at all stages of soil development. Nonetheless, the contribution of bacteria, especially actinomycetes to litter turnover became more pronounced as soil age increased in detriment of archaea, fungi and protozoa, more prominent in recently deglaciated terrain.

scholarly journals Influence of Seasonal Environmental Variables on the Distribution of Presumptive Fecal Coliforms around an Antarctic Research Station

2003 ◽  
Vol 69 (8) ◽  
pp. 4884-4891 ◽  
Author(s):  
Kevin A. Hughes
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Sea Ice ◽  
Fecal Coliform ◽  
Algal Blooms ◽  
Austral Summer ◽  
Fecal Coliforms ◽  
Late Winter ◽  
Research Station ◽  
The Antarctic

ABSTRACT Factors affecting fecal microorganism survival and distribution in the Antarctic marine environment include solar radiation, water salinity, temperature, sea ice conditions, and fecal input by humans and local wildlife populations. This study assessed the influence of these factors on the distribution of presumptive fecal coliforms around Rothera Point, Adelaide Island, Antarctic Peninsula during the austral summer and winter of February 1999 to September 1999. Each factor had a different degree of influence depending on the time of year. In summer (February), although the station population was high, presumptive fecal coliform concentrations were low, probably due to the biologically damaging effects of solar radiation. However, summer algal blooms reduced penetration of solar radiation into the water column. By early winter (April), fecal coliform concentrations were high, due to increased fecal input by migrant wildlife, while solar radiation doses were low. By late winter (September), fecal coliform concentrations were high near the station sewage outfall, as sea ice formation limited solar radiation penetration into the sea and prevented wind-driven water circulation near the outfall. During this study, environmental factors masked the effect of station population numbers on sewage plume size. If sewage production increases throughout the Antarctic, environmental factors may become less significant and effective sewage waste management will become increasingly important. These findings highlight the need for year-round monitoring of fecal coliform distribution in Antarctic waters near research stations to produce realistic evaluations of sewage pollution persistence and dispersal.

scholarly journals Cascading effects in freshwater microbial food webs by predatory Cercozoa, Katablepharidacea and ciliates feeding on aplastidic bacterivorous cryptophytes

2020 ◽  
Vol 96 (10) ◽  
Author(s):  
Karel Šimek ◽  
Vesna Grujčić ◽  
Indranil Mukherjee ◽  
Vojtěch Kasalický ◽  
Jiří Nedoma ◽  
...  
Keyword(s):  
Food Webs ◽  
Grazing Pressure ◽  
Heterotrophic Nanoflagellates ◽  
Cascading Effects ◽  
Microbial Food Webs ◽  
Feeding Modes ◽  
Hybridization Probes ◽  
Food Vacuoles ◽  
Freshwater Reservoir

ABSTRACT Heterotrophic nanoflagellates (HNF) are considered as major planktonic bacterivores, however, larger HNF taxa can also be important predators of eukaryotes. To examine this trophic cascading, natural protistan communities from a freshwater reservoir were released from grazing pressure by zooplankton via filtration through 10- and 5-µm filters, yielding microbial food webs of different complexity. Protistan growth was stimulated by amendments of five Limnohabitans strains, thus yielding five prey-specific treatments distinctly modulating protistan communities in 10- versus 5-µm fractions. HNF dynamics was tracked by applying five eukaryotic fluorescence in situ hybridization probes covering 55–90% of total flagellates. During the first experimental part, mainly small bacterivorous Cryptophyceae prevailed, with significantly higher abundances in 5-µm treatments. Larger predatory flagellates affiliating with Katablepharidacea and one Cercozoan lineage (increasing to up to 28% of total HNF) proliferated towards the experimental endpoint, having obviously small phagocytized HNF in their food vacuoles. These predatory flagellates reached higher abundances in 10-µm treatments, where small ciliate predators and flagellate hunters also (Urotricha spp., Balanion planctonicum) dominated the ciliate assemblage. Overall, our study reports pronounced cascading effects from bacteria to bacterivorous HNF, predatory HNF and ciliates in highly treatment-specific fashions, defined by both prey-food characteristics and feeding modes of predominating protists.

Phagotrophic phytoflagellates in microbial food webs

Hydrobiologia ◽  
1988 ◽  
Vol 159 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Karen Glaus Porter
Keyword(s):  
Food Webs ◽  
Microbial Food Webs

Seasonal succession of zooplankton in coastal waters of the Argentine Sea (Southwest Atlantic Ocean): prevalence of classical or microbial food webs

2013 ◽  
Vol 9 (4) ◽  
pp. 371-382 ◽  
Author(s):  
María Delia Viñas ◽  
Rubén Mario Negri ◽  
Georgina Daniela Cepeda ◽  
Daniel Hernández ◽  
Ricardo Silva ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Food Webs ◽  
Coastal Waters ◽  
Seasonal Succession ◽  
Southwest Atlantic ◽  
Argentine Sea ◽  
Microbial Food Webs

Experimental bottom-up influences on microbial food webs in eutrophic shallow waters of the Baltic Sea

1993 ◽  
Vol 25 (2) ◽  
pp. 991-994
Author(s):  
U. Schiewer ◽  
R. Heerkloss ◽  
K. Gocke ◽  
G. Jost ◽  
H.-P. Spittler ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Food Webs ◽  
Shallow Waters ◽  
The Baltic Sea ◽  
Bottom Up ◽  
Microbial Food Webs ◽  
The Baltic
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