Physical Processes Controlling Bacterial Distribution and Variability in the Upper St. Lawrence Estuary

Painchaud, Jean; Lefaivre, Denis; Therriault, Jean‐Claude; Legendre, Louis

doi:10.2307/1352362

Cited by 24 publications

(24 citation statements)

References 36 publications

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“…Similar results were found when freshwater bacteria were captured in diffusion chambers and incubated at marine salinities (38,43). However, one study exposed freshwater bacterioplankton to a range of estuarine salinities in the St. Lawrence estuary and found that they grew equally well when exposed to 5-ppt salinity but grew at reduced rates at 10 ppt and above (26). We detected a change in the composition of bacterioplankton communities at salinities as low as 1 ppt in summer and fall, but this change did not represent a wholesale replacement of the river populations.…”

Section: Discussionmentioning

confidence: 65%

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Crump

Hopkinson

Sogin

et al. 2004

Appl Environ Microbiol

413

342

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Shifts in bacterioplankton community composition along the salinity gradient of the Parker River estuary and Plum Island Sound, in northeastern Massachusetts, were related to residence time and bacterial community doubling time in spring, summer, and fall seasons. Bacterial community composition was characterized with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA. Average community doubling time was calculated from bacterial production ([ 14 C]leucine incorporation) and bacterial abundance (direct counts). Freshwater and marine populations advected into the estuary represented a large fraction of the bacterioplankton community in all seasons. However, a unique estuarine community formed at intermediate salinities in summer and fall, when average doubling time was much shorter than water residence time, but not in spring, when doubling time was similar to residence time. Sequencing of DNA in DGGE bands demonstrated that most bands represented single phylotypes and that matching bands from different samples represented identical phylotypes. Most river and coastal ocean bacterioplankton were members of common freshwater and marine phylogenetic clusters within the phyla Proteobacteria, Bacteroidetes, and Actinobacteria. Estuarine bacterioplankton also belonged to these phyla but were related to clones and isolates from several different environments, including marine water columns, freshwater sediments, and soil.Estuarine waters contain strong biological and chemical gradients established by the mixing of freshwater and seawater and modified by autochthonous biological activity. Many of these gradients, including salinity, nutrient concentration, organic matter composition, and bacteriovore community composition, are thought to influence the composition of natural bacterioplankton communities (2, 11). Such changes in environmental conditions, when recreated in mesocosm and microcosm experiments, caused shifts in the phylogenetic composition of bacterioplankton communities (10,19,32,41). It is therefore reasonable to predict that similar shifts will occur in natural freshwater and marine bacterioplankton communities when they encounter estuarine gradients, leading to the development of an estuarine community.Several studies have described estuarine microbial diversity and some have demonstrated how freshwater and marine bacterioplankton communities mix along estuarine gradients (3,4,8,14,21,37), but few reports have provided evidence of a unique estuarine bacterioplankton community. This is partly due to the dynamic nature of estuaries and the difficulty in distinguishing estuarine populations from those that wash in from adjacent environments. Crump et al. (6) identified putative estuarine bacteria associated with particles in the Columbia River estuarine turbidity maximum (ETM) by comparing environmental clone libraries of PCR-amplified 16S ribosomal DNA (rDNA) from the river, the estuary, and the coastal ocean. Similarly, Hollibaugh et al. (14) demonstrated the mixing of bacter...

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Section: Discussionmentioning

confidence: 65%

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Crump

Hopkinson

Sogin

et al. 2004

Appl Environ Microbiol

413

342

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“…Topographically modified flows give rise to very large tidal ranges and currents (up to 10 m and 3 m s −1 , respectively; Mertz and Gratton, 1990). In this tidally energetic region, wind mixing is 1 to 2 orders of magnitude smaller than tidal mixing (Painchaud et al, 1995). Owing to the resuspension of bottom sediments (tide, wind, or wave generated) and the net non-tidal estuarine circulation (d'Anglejan and Smith, 1973), a well-developed turbidity maximum stretches between Île d'Orléans and Île-aux-Coudres (Painchaud and Therriault, 1989), where suspended particulate matter concentrations vary from 10 to more than 200 mg L −1 (Silverberg and Sundby, 1979).…”

Section: Study Area -St Lawrence Estuary and Gulfmentioning

confidence: 99%

Spatial variability in surface-water <i>p</i>CO<sub>2</sub> and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

Dinauer

Mucci

2017

Biogeosciences

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Abstract. The incomplete spatial coverage of CO 2 partial pressure (pCO 2 ) measurements across estuary types represents a significant knowledge gap in current regional-and global-scale estimates of estuarine CO 2 emissions. Given the limited research on CO 2 dynamics in large estuaries and bay systems, as well as the sources of error in the calculation of pCO 2 (carbonic acid dissociation constants, organic alkalinity), estimates of air-sea CO 2 fluxes in estuaries are subject to large uncertainties. The Estuary and Gulf of St. Lawrence (EGSL) at the lower limit of the subarctic region in eastern Canada is the world's largest estuarine system, and is characterized by an exceptional richness in environmental diversity. It is among the world's most intensively studied estuaries, yet there are no published data on its surface-water pCO 2 distribution. To fill this data gap, a comprehensive dataset was compiled from direct and indirect measurements of carbonate system parameters in the surface waters of the EGSL during the spring or summer of 2003-2016. The calculated surface-water pCO 2 ranged from 435 to 765 µatm in the shallow partially mixed upper estuary, 139-578 µatm in the deep stratified lower estuary, and 207-478 µatm along the Laurentian Channel in the Gulf of St. Lawrence. Overall, at the time of sampling, the St. Lawrence Estuary served as a very weak source of CO 2 to the atmosphere, with an area-averaged CO 2 degassing flux of 0.98 to 2.02 mmol C m −2 d −1 (0.36 to 0.74 mol C m −2 yr −1 ). A preliminary analysis revealed that respiration (upper estuary), photosynthesis (lower estuary), and temperature (Gulf of St. Lawrence) controlled the spatial variability in surface-water pCO 2 . Whereas we used the dissociation constants of Cai and Wang (1998)

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“…While much of this work has focused on phytoplankton, bacterial populations also rapidly respond to physical, chemical, and biological changes in eutrophying estuarine systems (Paerl et al , 2003. Few studies have been conducted to assess the interactions among organic matter, nutrient inputs, particle loading, and bacteria in eutrophic systems (Painchaud et al 1995, Artigas 1998, Capriulo et al 2002, Schumann et al 2003.…”

Section: Introductionmentioning

confidence: 99%

VIBRIO AND PHYTOPLANKTON DYNAMICS DURING THE SUMMER OF 2004 IN A EUTROPHYING ESTUARY

Hsieh

Fries

Noble

2007

Ecological Applications

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Abstract. Bacterioplankton response to eutrophication is a critical part of the transition from phytoplankton blooms to bottom-water hypoxia in estuaries. This topic is of particular concern when endemic bacterial populations, such as Vibrio sp., may pose a health risk to local human populations using estuaries for recreation and food. The purpose of this study was to observe the dynamics of both Vibrio and phytoplankton in the Neuse River Estuary (NRE) in North Carolina, USA, during the summer of 2004. Vibrio concentrations, particle suspension characteristics, and chlorophyll a were measured in surface water collected at a series of stations along the estuarine gradient. Consistent with previous studies, a strong positive relationship between Vibrio concentration and salinity was found. Both Vibrio sp. and phytoplankton concentrations increased moving downstream, but beyond the salt front, phytoplankton declined while Vibrio sp. concentrations continued to increase. In surface waters, a large portion of suspensions was comprised of phytoplankton cells. The fraction of Vibrio cells attached to phytoplankton increased with phytoplankton concentration and decreased with increasing salinity. These observations of Vibrio dynamics in the NRE provide evidence that populations interact with phytoplankton populations in surface waters. This information may prove critical for models of estuarine bacterial dynamics in response to eutrophication.

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Physical Processes Controlling Bacterial Distribution and Variability in the Upper St. Lawrence Estuary

Cited by 24 publications

References 36 publications

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Spatial variability in surface-water <i>p</i>CO<sub>2</sub> and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

VIBRIO AND PHYTOPLANKTON DYNAMICS DURING THE SUMMER OF 2004 IN A EUTROPHYING ESTUARY

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Physical Processes Controlling Bacterial Distribution and Variability in the Upper St. Lawrence Estuary

Cited by 24 publications

References 36 publications

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

Spatial variability in surface-water &lt;i&gt;p&lt;/i&gt;CO&lt;sub&gt;2&lt;/sub&gt; and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

VIBRIO AND PHYTOPLANKTON DYNAMICS DURING THE SUMMER OF 2004 IN A EUTROPHYING ESTUARY

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Spatial variability in surface-water <i>p</i>CO<sub>2</sub> and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)