Microbial trophodynamics in the Delaware Estuary

Coffin, RB; Sharp, JH

doi:10.3354/meps041253

Cited by 114 publications

(87 citation statements)

References 25 publications

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“…Coffin and Sharp ( 1987) reported strong coupling between bacterial production and predation in the Delaware estuary, with flagellate grazing rates frequently equivalent to bacterial production rates. In the Parker estuary (Massachussetts), bacterial production showed a strong and significant correlation with grazing (Wright et al 1987).…”

Section: Resultsmentioning

confidence: 99%

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Bacterial dynamics in the upper St. Lawrence estuary

Painchaud

Lefaivre²,

Therriault³

et al. 1996

Limnology & Oceanography

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The distribution of free bacteria in the St. Lawrence estuary was interpreted by means of bacterial fluxes and hydrodynamic residence times, derived from a circulation model, and growth and grazing rates, obtained from cultures. Bacterial abundances decreased exponentially along the salinity gradient, from 3.9 x lo9 liter-' in freshwater to 0.5 x lo9 liter-l at salinity ~20. The rates of growth (0.02-0.08 h-l) and grazing (0.0 l-O.09 h-l) were strongly correlated (r = 0.82), which suggests that bacteria tended toward a state of trophodynamic equilibrium (growth E grazing). However, negative bacterial fluxes obtained from the model imply that the estuary is a sink for bacteria. Results from the circulation model and the cultures show that physical processes are important controlling factors of the distribution of bacteria and point IO predation as the process causing bacterial losses in the estuary. Calculations show that small imbalances between growth and grazing can account for the observed distribution.Rates of dispersion and growth and grazing are of the same order of magnitude, which shows that biological processes are nevertheless significant relative to physical processes. Although the distribution of free bacteria appears largely under hydrodynamic control, the bacterial community is characterized by significant biological rates and can experience large transformations during estuarine transit.

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Section: Resultsmentioning

confidence: 99%

“…pared to physical processes as determinants of the distribution (Wright and Cofhn 1984;Coffin and Sharp 1987;Sherr et al 19891). Clearly, there is a lack of studies linking estuarine hydrodynamics and bacterial dynamics.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Bacterial dynamics in the upper St. Lawrence estuary

Painchaud

Lefaivre²,

Therriault³

et al. 1996

Limnology & Oceanography

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“…The lack of any clear pattern might be a consequence of shorterterm variability in sediment transport and resuspension in the upper Bay. Temperature has been recognized as a very important physical factor affecting heterotrophic bacterioplankton (HBP) substrate uptake activity (Iriberri et al 1985, Pomeroy & Deibel 1986, Pomeroy et al 1991), abundance and production (Love11 & Konopka 1985. Coffin & Sharp 1987, Findlay et al 1991, White et al 1991.…”

Section: Discussionmentioning

confidence: 99%

Activity and distribution of attached bacteria in Chesapeake Bay

Griffith¹,

Shiah²,

Gloersen³

et al. 1994

Mar. Ecol. Prog. Ser.

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The purpose of this study was to further our understanding of the role of particle-associated bacteria in phytoplankton degradation in the Chesapeake Bay, USA, and to identify environmental parameters that control production by free and particle-associated bacteria. Surface and bottom waters at 10 stations along the length of the Bay were sampled over a 2 yr period. Samples were analyzed for temperature, salinity, chlorophyll, phaeophytin, particulate protein, thymidine incorporation (an estimate of bacterial growth rate), and bacterial total direct counts. Results demonstrated that freeliving bacteria were responsible for most of the total bacterial production, which was correlated with temperature and particulate protein, but not with chlorophyll. In contrast, attached bacteria were much more active than free-living bacteria on a per-cell basis. Cell-specific thymidine incorporation by freeliving bacteria correlated with temperature and particulate protein quantity, whereas that by attached bacteria correlated with temperature, particulate protein quantity and particulate organic quality, as indicated by extent of phytoplankton degradation.

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“…Although the estuary has a strong anthropogenic influence, the major input of organic matter has been shown to result from in situ phytoplankton production (Cifuentes et al 1988, Cifuentes 1991. Similarly, both phytoplankton (Pennock 1985, 1987, Pennock & Sharp 1986) and bacterial processes (Coffin & Sharp 1987, Lebo 1990) have been shown to influence the overall nutrient cycle.…”

Section: Study Areamentioning

confidence: 99%

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

Pennock¹,

Sharp²

1994

Mar. Ecol. Prog. Ser.

Self Cite

103

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The potential for Light-and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) of dissolved inorganic nitrogen (DIN) to PO, in river waters, accumulation of P into phytoplankton, and low rates of P regeneration. During summer, P no longer limited production. At this time DIN:POI ratios and bioassay experiments revealed the potential for nitrogen (N) limitation -particularly in the lower estuary -while particulate composition ratios and ecosystem nutrient flux estimates gave contradictory evidence. From these data it appears that N was potentially limiting to phytoplankton biomass but that the constant flux of N from upstream and rapid N regeneration maintained non-nutrient-limited steady-state growth. These data document a pattern of recurring system-wide variations in the factors that limit phytoplankton production over several annual sequences. These temporal and spatial variations are related to both light availability -as regulated by incldent light, suspended sediment concentration, and depth of the surface mixed-layerand nutrient availability -as determined by riverine inputs and in situ biogeochemical processes.

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Microbial trophodynamics in the Delaware Estuary

Cited by 114 publications

References 25 publications

Bacterial dynamics in the upper St. Lawrence estuary

Bacterial dynamics in the upper St. Lawrence estuary

Activity and distribution of attached bacteria in Chesapeake Bay

Temporal alternation between light- and nutrient-limitation of phytoplankton production in a coastal plain estuary

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