Seasonal variability of denitrification efficiency in northern salt marshes: An example from the St. Lawrence Estuary

Poulin, Patrick; Pelletier, Émilien; Saint-Louis, Richard

doi:10.1016/j.marenvres.2006.12.003

Cited by 25 publications

(17 citation statements)

References 53 publications

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“…In the present work, denitrification rate and nutrient flux measurements showed some variability within each season and within sites, as also reported in other works (e.g. Cabrita & Brotas 2000, Eriksson et al 2003, Poulin et al 2007). Accordingly, differences within and among sites, result from the natural variability within each system, given the number of parameters/variables that may interact and influence all of these processes.…”

Section: Discussionsupporting

confidence: 90%

“…Cornwell et al 1999, David et al 2006, Seitzinger et al 2006). In addition, other pathways contribute to this N removal in aquatic ecosystems (salt marshes included), such as dissimilatory nitrate reduction to ammonium (DNRA), or autotrophic path ways, such as anammox (anaerobic ammonium oxidation) or chemoautotrophic denitrification via sulfur or iron oxidation; the magnitude of which depends on the ecosystem type and its inherent characteristics (Eriksson et al 2003, Risgaard-Petersen et al 2004b, Burgin & Hamilton 2007, Poulin et al 2007.…”

Section: Discussionmentioning

confidence: 99%

“…More specifically, differences in denitrification rates between ecosystems may be due to several physical, chemical, and biological factors, such as temperature, light, NO 3 concentrations, oxygen availability, benthic microalgae, benthic fauna, and the presence/absence of plants (e.g. Kaplan et al 1979, Cornwell et al 1999, Herbert 1999, Eriksson et al 2003, Pinã-Ochoa & Alvarez-Cobelas 2006, Poulin et al 2007, Koop-Jacobsen & Giblin 2009.…”

Section: Discussionmentioning

confidence: 99%

“…However, regarding denitrification in estuaries, there are only few studies concerning mudflats (e.g. Cabrita & Brotas 2000, Risgaard-Petersen 2003, Sundbäck et al 2006) and even fewer concerning salt marshes , Koch et al 1992, White & Howes 1994, Eriksson et al 2003, Poulin et al 2007). In these studies, different techniques were applied and therefore restrict comparisons be tween systems.…”

Section: Introductionmentioning

confidence: 99%

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Denitrification: an ecosystem service provided by salt marshes

Sousa¹,

Lillebø²,

Risgaard-Petersen³

et al. 2012

Mar. Ecol. Prog. Ser.

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We hypothesized that denitrification rates, as an N removal process, would be enhanced in salt marsh rhizosediments as compared to sediments without vegetation (bare mudflats). Denitrification rates (measured by the 15 N-isotope pairing technique), potential nitrification, and nutrient fluxes were seasonally quantified in a Spartina maritima salt marsh and in adjacent bare mudflats. Potential nitrification rates were significantly higher in autumn and winter, but there were no significant differences between the bare mudflats and S. maritima vegetated sediment. Seasonally, denitrification rates in vegetated sediments under dark conditions were significantly higher in winter (676 ± 497 µmol N 2 m −2 h −1 , mean ± SD), whereas bare mudflats showed a maximum rate of 151 ± 24 µmol N 2 m −2 h −1 in summer. The high denitrification rates recorded in winter may be due to many abiotic and biotic factors, namely higher potential nitrification and nitrate availability in the water column, lower competition for nitrogen within the sediment, and less competition between plants, microphytobenthos, and nitrifiers, especially in dark conditions. Hence, during winter, there was a higher contribution of S. maritima marshes to N removal through denitrification, highlighting the role of the marshes in this ecosystem service. As a whole, considering the seasonal variations of the studied processes, it cannot be concluded whether or not annual denitrification was significantly different between the vegetated sediment and the bare mudflats.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Denitrification: an ecosystem service provided by salt marshes

Sousa¹,

Lillebø²,

Risgaard-Petersen³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…Salt marshes are highly dynamic environments and are among the most productive ecosystems in the world (WOODWARD and WUI, 2001). They are characterized by high primary production rates and by intense remineralization processes within the surface sediment (BILLEN and LANCELOT, 1988;POULIN et al, 2007). In addition, they act as natural filters of allochtonous pollutants and actively transform nutrient loads received from the watershed before their introduction into the coastal environment (BALDWIN and MITCHELL, 2000).…”

Section: Introductionmentioning

confidence: 99%

Benthic diatom communities from two salt marshes of the St. Lawrence Estuary (Canada)

Sève¹,

Poulin

Pelletier

et al. 2010

rseau

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Microphytobenthic diatom communities were investigated in the high and low sections of two salt marshes of the Lower St. Lawrence Estuary (eastern Canada): one featuring a sandy low marsh zone (Pointe-aux-Épinettes; PE) and one with a muddy low marsh area (Pointe-au-Père; PP). Based on diatom composition and diversity, bacterial abundance, chlorophyll-a, phaeopigments and geochemical analyses (Corg, Ntot, granulometry, extracellular polymeric substances), the PP high marsh area appeared to be singular compared to the other sampling sites. Estimated surface biomass ranged from 11 to 71 g C•m-2in the PE marsh and from 24 to 486 g C•m-2in the PP marsh. A higher diversity of diatom species was observed in the PP high marsh area with a dominance of epipelic forms, in opposition to the dominant epipsammic forms at the other sites. Statistical analyses showed that diatom density was mainly affected by nutrient availability while the relative abundance of epipelic and epipsammic species was related to sediment grain size. This study provides original data on the composition of benthic diatoms in surface sediments in St. Lawrence saltmarshes during summer time that represent the first step to the determination of the DBI (Diatom biological index) of these northern environments.

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Chemical and Microbial Contamination Baseline in the Saguenay–St. Lawrence Marine Park (Eastern Canada): Concentrations and Fluxes From Land-Based Sources

Lemaire

Pelletier

2013

Arch Environ Contam Toxicol

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Stretching halfway between the Canadian Great Lakes and the Atlantic Ocean, the Saguenay-St. Lawrence Marine Park is subject to environmental issues being exposed to untreated or uncontrolled point and non-point sources of anthropogenic contamination. This article provides a first estimation of chemical and microbial contamination entering the marine park from the discharges of local municipal effluents and the inputs of tributaries in the summer period. Suspended particulate matter (SPM), nutrients, particulate carbon (PC) and nitrogen, trace metals, and fecal coliform bacteria were determined in surface brackish waters at upstream boundaries, in freshwater of 11 tributaries, and in nine sewage effluents from small communities settled along the marine park. Most tributaries have SPM < 10 mg L(-1) and contributed to a total of ~47 tons day(-1), thus representing a small proportion of daily SPM transported by Saguenay River (200 tons day(-1)) and St. Lawrence River (6.3 × 10(3) tons day(-1)). As expected, untreated sewage effluents showed high fecal contamination (0.2-6.0 × 10(6) CFU 100 mL(-1)), high NO x levels (4-33 μmol L(-1)) and high concentrations of particulate organic carbon (7-62 mg L(-1)). However, all tributaries had low coliforms (<230 CFU 100 mL(-1)), low PC (0.3-1.1 mg L(-1)), and low nutrients (NO(x) < 3.3 μmol L(-1)), with the exception of the Moulin-à-Baude River, a small tributary (2.3 × 10(5) m(3) day(-1)) clearly contaminated by human activities. Detailed analysis of 14 metals and metalloids in SPM did not show any clear contamination trend between sewage effluents and tributaries, except for Grandes-Bergeronnes River, where most trace metals appeared to be greater than for other rivers. Regarding global inputs, results showed that despite their relatively high pollutants load, inputs from local sewages and small tributaries remained minor contributors compared with upstream inputs, i.e., Saguenay River and St. Lawrence River. However, we illustrate that some local hydrodynamic factors in bays and inlets must be taken into account when evaluating risks associated with sewage discharges.

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Seasonal variability of denitrification efficiency in northern salt marshes: An example from the St. Lawrence Estuary

Cited by 25 publications

References 53 publications

Denitrification: an ecosystem service provided by salt marshes

Denitrification: an ecosystem service provided by salt marshes

Benthic diatom communities from two salt marshes of the St. Lawrence Estuary (Canada)

Chemical and Microbial Contamination Baseline in the Saguenay–St. Lawrence Marine Park (Eastern Canada): Concentrations and Fluxes From Land-Based Sources

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