Factors related to heterotrophic bacterial and flagellate abundance in temperate rivers

Bk, Basu; Pick, Frances R.

doi:10.3354/ame012123

Cited by 27 publications

(15 citation statements)

References 23 publications

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“…Previous studies have not generally observed a relationship between DOC concentrations and indicators of bacterial activity and growth (i.e., bacterial production and abundance) in rivers and estuaries (Findlay et al 1996, Basu & Pick 1997. This may be due, in part, to the continuum of reactivity within the DOC pool, because it is sometimes a small percentage of the DOC pool that supports the majority of bacterial carbon utilization (Wright & Hobbie 1965, Kirchman et al 1991, but see Amon & Benner 1996.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 98%

Bacterial consumption of DOC during transport through a temperate estuary

Raymond¹,

Bauer²

2000

Aquat. Microb. Ecol.

192

123

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Bacterial utilization of natural levels of dissolved organic carbon (DOC) was measured in the York River estuary, a sub-estuary of the Chesapeake Bay. This study was undertaken in order to elucidate spatial and temporal changes in bacterial carbon utilization and to evaluate its importance as a pathway for organic matter transformation in estuaries. Multiple pools of DOC were defined based on decomposition kinetics. The first pool (G 1 ) made up a mean of 2.8% of total DOC and had turnover times of ≤ 5 d. The second pool (G 2 ) comprised an average of 4.9% of total DOC and had turnover times of ~1 mo. Our data indicate that although the total amount of DOC utilized was low, there was a continual supply of both the G 1 and G 2 fractions within the estuary. Bacterial growth efficiency on the G 1 pool averaged 28%. The production of CO 2 through bacterial respiration of the G 1 pool could not balance CO 2 evasion for the majority of the estuary. Bacterial DOC degradation in the York River estuary was limited by temperature for the majority of the year. This temperature constraint coupled with relatively short hydrologic residence times resulted in the export of labile DOC from the estuary prior to complete bacterial decomposition. We estimate that ~10% of the riverine DOC exported annually from estuaries to the mid-Atlantic Bight (MAB) is a labile fraction of DOC that is not utilized within the estuaries due to temperature constraints on estuarine bacteria. This DOC is not inherently recalcitrant and is an allochthonous source of labile DOC for the coastal MidAtlantic Ocean.KEY WORDS: Dissolved organic carbon (DOC) · Heterotrophy · Mid-Atlantic Bight · Carbon export · Chesapeake Bay · York River Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 22: [1][2][3][4][5][6][7][8][9][10][11][12] 2000 This continuum of reactivity is described in the multi-G model (Berner 1980, Westrich & Berner 1984, where the decay (i.e., removal) of organic matter is dictated by the sequential loss of discrete pools with decreasing decay constants. Previous studies have not generally observed a relationship between DOC concentrations and indicators of bacterial activity and growth (i.e., bacterial production and abundance) in rivers and estuaries (Findlay et al. 1996, Basu & Pick 1997. This may be due, in part, to the continuum of reactivity within the DOC pool, because it is sometimes a small percentage of the DOC pool that supports the majority of bacterial carbon utilization (Wright & Hobbie 1965, Kirchman et al. 1991, but see Amon & Benner 1996. Søndergaard & Middelboe (1995) found that the average percentage of labile (defined as the amount utilized in ≤ 7 d) DOC in lakes, rivers, and marine systems was 14, 19, and 19% of the total DOC pool, respectively. Across systems the concentration of labile DOC generally increased with increasing total DOC concentrations, with an average response of an additional 0.17 µM labile DOC for every 1.0 µM increase in total DOC (Søndergaard & ...

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Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 98%

Bacterial consumption of DOC during transport through a temperate estuary

Raymond¹,

Bauer²

2000

Aquat. Microb. Ecol.

192

123

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“…analyses have been published, expanding the originally very limited marine and freshwater databases to include rivers [14], salt lakes [15], hypertrophic ecosystems [16] and open ocean communities [17,18]. As a result, the link between bacterial abundance and phytoplankton biomass remains as one of the few undisputed patterns in aquatic microbial ecology.…”

Section: Achievements In Aquatic Microbial Ecologymentioning

confidence: 99%

Comparative analyses in aquatic microbial ecology: how far do they go?

Gasol

2000

FEMS Microbiology Ecology

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Methodological developments in recent years have led to an increase in empirical databases on the abundance and functions of aquatic microbes, now allowing synthesis studies. Most of these studies have adopted a comparative approach, such that comparative analyses are now available for most aspects of aquatic microbial food webs (more than 50 papers published in the last 15 years). Some of these analyses apparently yield conflicting results, introducing confusion and unnecessary disputes in the field. We briefly review the comparative analyses so far produced and we highlight generalities, show that some of the perceived discrepancies largely derive from partial analyses of a general underlying trend and formulate predictions based on these general trends that provide new avenues for research. ß

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“…Two studies applying a water quality model to Saar, Moselle and Rhine (Schöl et al, 1999;Schöl et al, 2002) show a low grazing pressure of metazooplankton on phytoplankton in former years. This low importance of metazooplankton in rivers was also found by Basu and Pick (1997), Karrasch et al (2001) and Weitere et al (2005).…”

Section: Metazooplanktonmentioning

confidence: 78%

Comparison of the components of the planktonic food web in three large rivers (Rhine, Moselle and Saar)

Bergfeld¹,

Scherwaß²,

Ackermann³

et al. 2008

River Research & Apps

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The dynamics of phyto-, bacterio-, proto-and metazooplankton were investigated for a period of 22 months fortnightly from March 1999 until December 2000 in the rivers Moselle, Saar and Rhine. Plankton abundances reached the lowest values in the Rhine and the highest in the Saar. Protozoa and not the much more studied metazoa clearly dominate the zooplankton not only by number but also by biomass by about 90%. We show that the plankton biomass in each of the rivers is the result of the interplay of the grazing by benthic predators and of the human induced factors such as river morphology, water residence time and nutrient load. Furthermore, we compare our study with the planktonic food web of three other large European rivers. The comparison between all studies revealed a general rise of the absolute mean biomass of all heterotrophic planktonic food web components (bacteria, protozoa, metazoa) parallel to an increase of the algal biomass of the river. For the rivers Rhine, Moselle and Saar, the average biomass of all investigated plankton groups was very low compared to the values obtained in the rivers Meuse, Loire and Elbe. The relative importance of organisms of the microbial food web increased with a decrease of the algal biomass or organic carbon content, respectively, in each of the rivers. We postulate that with a sinking nutrient level in the Rhine, the microbial food web components will become even more important within the plankton than they already are.

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Factors related to heterotrophic bacterial and flagellate abundance in temperate rivers

Cited by 27 publications

References 23 publications

Bacterial consumption of DOC during transport through a temperate estuary

Bacterial consumption of DOC during transport through a temperate estuary

Comparative analyses in aquatic microbial ecology: how far do they go?

Comparison of the components of the planktonic food web in three large rivers (Rhine, Moselle and Saar)

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