Origins, structure, and trophic significance of amorphous seston in a blackwater river

Carlough, Leslie A.

doi:10.1111/j.1365-2427.1994.tb00857.x

Cited by 25 publications

(26 citation statements)

References 64 publications

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“…This might be caused by aggregation of smaller aggregates. Electron microscopy observations generally reveal a predominately fibrillar matrix of aggregates (Leppard 1992, Carlough 1994) At both stations -10% of the bacterial community was found attached to particles, which is in good agreement with (1992). Bacteria colonizing these particles start to utilize labile organic material and simultaneously solubilize the organic matrix of the aggregates.…”

supporting

confidence: 74%

“…At Stn 1, DOC concentrations averaged 3.4 mg C I-' and were about 2 times higher at Stn 2. These concendischarge ( m s -'l trations are comparable to those found in other fresh- , Findlay et al 1991, Carlough 1994 were able to roughly estimate DOC turnover rates; these rates are biased, however, by the constant temtention is also supported by a significant correlatlon perature used (20°C) and the long incubation period between BODl and BOD5 and chl a in the River (2 d) used for calculating the respiration. At Stns 1 and Danube (r = 0.545 and 0.533, respectively, n = 105, p < 2, DOC turnover rates ranged from 0.02 to 0.15 and 0.001; data not shown), while at Stn 2 BOD2 and BOD, 0.01 to 0.36 d-l, respectively.…”

supporting

confidence: 49%

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Remineralization of organic matter and degradation of the organic fraction of suspended solids in the River Danube

Hoch¹,

Berger²,

Kavka³

et al. 1995

Aquat. Microb. Ecol.

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To determine the role of microbes in the degradation of organic matter in the River Danube, the biochemical oxygen demand (BOD) was followed over 2 and 5 d from July to December 1993, and the fluctuations of the microbial community were monitored in incubation flasks over the incubation periods of 2 and 5 d from January to December 1993. In the BOD flasks, bacterial abundance increased by up to 63% of the initial abundance during the first l 5 h of incubation followed by an increase in flagellates, reaching their maximum about 35 h after starting the incubation. After 60 h, bacterial abundance declined to 15 % of the initial density. This rapid fluctuation indicates that the BOD method routinely used to monitor water quality may be inappropriate for measuring the degradability of organic matter since the confined bacterial community is efficiently controlled by flagellates. The role and degradability of the organic coating of suspended solids was evaluated by Alcian blue staining and transmission light microscopy. Degradation experiments revealed that the number of particles decreased by up to 50% during the incubation period indicating rapid microbial utilization of this particulate matter.

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supporting

confidence: 74%

supporting

confidence: 49%

Remineralization of organic matter and degradation of the organic fraction of suspended solids in the River Danube

Hoch¹,

Berger²,

Kavka³

et al. 1995

Aquat. Microb. Ecol.

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“…In the River Danube, colonized particles were on average i 3 pm in diameter, whiie in the Donaukanai mean particle diameter was 16 pm; similar diameters were found for suspended solids in the Ogeechee River, USA (Carlough 1994). Studies in different aquatic systems indlcate that with decreasing particle size, microbial biomass and activity increases (Wallace et al 1982, Kondratieff & Simmons 1985, Almeida & Alcantara 1992.…”

Section: Discussionmentioning

confidence: 55%

Bacterial colonization of suspended solids in the River Danube

Berger¹,

Hoch

Kavka

et al. 1996

Aquat. Microb. Ecol.

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The River Danube was studied in the vicinity of Vienna (Austria) to examine the Interactions among suspended matter, bacterial colonization and dissolved organic matter on a medium temporal and spatial scale. The concentration of suspended matter, the total number of particles and the number of bacteria attached to particles correlated with discharge rates. In the River Danube, 39% of the particles stained with Alcian Blue were colonized by bacteria, but only a small number of particles were heavily colonized. About 9.5% of the total bacterial community was found to b e associated with particles, abundance of free-living bacteria varied between 2.4 and 7.8 X 106 cells ml-' and attached bactenal abundance varied from 0.1 to 1.4 X 106 cells ml-l On average, 8 bacteria particle-' were found in the River Danube. Smaller particles were colonized more densely by bacteria than larger particles In the River Danube, 60 % of the particles were found to be in the size range of > 9 to 100 pm2 and 57 ' % of the attached bacteria colonized thls slze class.

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“…Thus the conversion of substances within estuarine environments is more complex than that of streams, rivers, lakes, and the sea. In this context suspended particulate matter, especially organic particles, appears to be an important focus for the biological conversion of substances [19], which may sometimes dominate microbial activity compared to the surrounding water [20]. Here we particles L -1 determined for the tidally unaffected reach of the river Elbe at Magdeburg (Baborowski, pers.…”

Section: Discussionmentioning

confidence: 99%

Free and Particle‐associated Extracellular Enzyme Activity and Bacterial Production in the Lower Elbe Estuary, Germany

Karrasch

Ullrich

Mehrens

et al. 2003

Acta hydrochim. hydrobiol.

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A high abundance of particles and aggregates is a characteristic of estuaries and may represent important loci of increased bioproductivity and microbial activity. From a survey performed in the Elbe estuary, particle concentration (using a particle counter), bacterial biomass and abundance (AODC method), bacterial production rates ([3H] thymidine method) and the microbial extracellular enzyme activity of 11 enzymes (MUF and MCA method) were determined with particular respect to their relationship to particles and aggregates (sizefractionated). Although higher particle abundance was found compared to other sections of the river Elbe, neither relative nor absolute bacterial activity associated with particles and aggregates was enhanced. The activity of free dissolved microbial enzymes was found to dominate the breakdown of organic material. The productivity of free dispersed bacteria ≥0.2…<2 μm (2…69%) and bacteria attached to small particles ≥2…<10 μm (27…93%) considerably surpassed that of bacteria associated with particles >10 μm (0…40%). This indicates that the larger particles and aggregates do not always contribute substantially to the overall microbial activity in rivers and estuaries.

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Origins, structure, and trophic significance of amorphous seston in a blackwater river

Cited by 25 publications

References 64 publications

Remineralization of organic matter and degradation of the organic fraction of suspended solids in the River Danube

Remineralization of organic matter and degradation of the organic fraction of suspended solids in the River Danube

Bacterial colonization of suspended solids in the River Danube

Free and Particle‐associated Extracellular Enzyme Activity and Bacterial Production in the Lower Elbe Estuary, Germany

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