Sediment—water exchanges of ammonium and phosphate in intertidal and subtidal areas of a mesotidal coastal lagoon (Ria Formosa)

Falcão, Manuela; Vale, Carlos

doi:10.1007/978-94-011-5266-2_16

Cited by 24 publications

(44 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This clearly indicates that tidal excursion causes the export of nutrients from sediment to the water column independently of the season. Similar finding were found by Falcão and Vale (1998) in a SW European coastal lagoon and Cabrita et al,1999 in the Tagus (Portugal) meso-tidal estuary. Minor seasonal variations were found at the Ria of Viveiro for tide-induced transport of nitrate, nitrite and phosphate (Table 3), while tide-induced transport of ammonium was almost two times higher in April than in July.…”

Section: Sediment Water Exchanges Associated To Tidal Floodingsupporting

confidence: 86%

“…The way in which water floods the intertidal area is rather complex, during the first minutes of the inundation process sediment may be resuspended and seawater mixed with pore water of surface sediment layers. The result is a change in the composition of the surface water, previously achieved during the air-exposed situation (Falcão and Vale, 1998;Huettel et al, 1998;Jahnke, 2003). This change may increase the nutrient exchange, which coupled with benthic regeneration, can support the nutrient demand of primary producers (Nixon et al, 1976;Fisher et al, 1982;Boynton and Kemp, 1985) This work aimed to quantify the contribution of intertidal sediments to the nutrient budget of two Northern Galician Rias (Iberian Peninsula, SW Europe).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Exchange of nutrients across the sediment–water interface in intertidal ria systems (SW Europe)

Ospina-Álvarez

Caetano

Vale

et al. 2014

Journal of Sea Research

View full text Add to dashboard Cite

Concentrations of nitrate, nitrite, ammonium, phosphate and silicate were determined in river water, tidal water that floods the intertidal sediment (flooding water) and pore water of those sediments in the Northern Galician Rias of Ortigueira and Viveiro (NW Iberian Peninsula). The field surveys were done in the productive seasons of spring and summer 2008. Short-sediment cores and tidal flooding water were sampled at the intertidal area during the first 20 minutes that the tide inundates the sampling site. Nutrient fluxes of rivers (Lourido and Landro) flowing into the rias were in the order of H 4 SiO 4 > NO . Nutrients inputs from those rivers were low relative to the nutrient discharge of the entire coastal area. Striking changes of nutrient concentrations in flooding and pore waters of intertidal sediments were observed in the short periods of tidal inundation. Nutrient fluxes driven by molecular diffusion and tide-induced transport across the sediment-water interface were quantified and compared to the nutrient river contribution. Diffusive fluxes ranged from 9.3 to 13.7 nmol·cm -2 ·d -1 for nitrate and nitrite, -1.32 to 30.1 nmol·cm -2 ·d -1 for ammonium, -0.01 to 0.49 nmol·cm -2 ·d -1 for phosphate, and -13.2 to 0.2 nmol·cm -2 ·d -1 for silicate. Tide-induced transport always exceeded diffusive fluxes, with differences reaching up to four orders of magnitude for silicate. The overall results of this study emphasize the relevance of tidal water movement in promoting the sediment-water exchange of nutrients in intertidal sub-ecosystems.

show abstract

Section: Sediment Water Exchanges Associated To Tidal Floodingsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Exchange of nutrients across the sediment–water interface in intertidal ria systems (SW Europe)

Ospina-Álvarez

Caetano

Vale

et al. 2014

Journal of Sea Research

View full text Add to dashboard Cite

show abstract

“…Therefore, the calibration and validation of the hydrodynamic object is analysed in this study and based on and at the sea boundaries, were obtained in several works carried out by the Marine Research Institute (Falcão & Vale, 1990;Vale et al, 1992;Falcão & Vale, 1995;Falcão, 1997, Falcão & Vale, 1998MAOT, 2000;Falcão & Vale, 2003;Newton et al, 2004). A study using the full model complexity, including its calibration and validation is currently being carried out and it will be the subject of an upcoming paper.…”

Section: Hydrodynamic and Biogeochemical Modelling Of The Lagunary Symentioning

confidence: 99%

Biogeochemical modelling of Ria Formosa (South Portugal)

et al. 2008

View full text Add to dashboard Cite

Obtained results suggest that the river network may have a significant effect on lagoon concentrations, in spite of the relatively low river flows, due to the high ammonium and nitrate loads. Scenarios reflecting increases in lagoon bathymetry through dredging operations suggest an increase in lagoon water washout time with potential impacts on water quality and impacts at a scale of tens of km. The obtained results are being used by the Ria Formosa Natural Park authority for management purposes and may be useful to feedback future updates of the watershed management plans, within the scope of the European Union WaterFramework Directive. The use of a lagoon scale models is therefore justified in this work.2

show abstract

“…The remineralisation of organic matter deposited within these zones results in the release of inorganic nitrogen and phosphorus to coastal waters (Rocha et al 1995, Falcão & Vale 1998, Rocha 1998. In situations where a large fraction of this remineralisation proceeds via denitrification, there may be a net loss of nitrogen from the system (e.g.…”

Section: Introductionmentioning

confidence: 99%

Carbon and nitrogen cycling on intertidal mudflats of a temperate Australian estuary. II. Nitrogen cycling

Cook¹,

Revill²,

Butler³

et al. 2004

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Benthic fluxes of dissolved nitrogen, rates of denitrification, N 2 fixation and NH 4 + upward flux within the sediment (calculated from porewater profiles) were measured on the upper and lower mudflats at 2 study sites, 1 in the upper, river-dominated part of the estuary, and 1 in the lower, more marine part of the Huon Estuary, Tasmania, Australia. The calculated upward flux of NH 4 + from within the sediment based on porewater profiles was generally in excess of measured benthic fluxes, suggesting that NH 4 + was reassimilated at the sediment surface by microphytobenthos (MPB). The ratio of total CO 2 (TCO 2 ):NH 4 + produced within the sediment was generally in excess of 15, and in some cases in excess of 60. Significant influxes and effluxes of dissolved organic nitrogen (DON) were measured where the activity of MPB was highest. At times, DON influxes and effluxes were well in excess of dissolved inorganic nitrogen (DIN) fluxes, highlighting the importance of measuring DON fluxes where the activity of MPB is high. Rates of denitrification were very low, and represented only a small loss of N from the sediment, most probably as a consequence of the activity of MPB. Estimates of nitrogen assimilation by MPB showed that N 2 fixation was likely to be the major source of nitrogen during the summer at the study site in the upper estuary. There was also a high estimated C:N ratio (~20) of TCO 2 and nitrogen assimilated at this site, suggesting that a significant proportion of primary production was exuded as dissolved organic carbon rather than cellular production.KEY WORDS: Microphytobenthos · Denitrification · Intertidal · Porewater · Dissolved organic nitrogen · Sediment · Nitrogen fixation · Sediment -water exchange Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 280: [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] 2004 Microphytobenthos (MPB) are ubiquitous on mudflats and may exert an important influence on nitrogen cycling processes in these environments (Underwood & Kromkamp 1999). Assimilation of nitrogen by MPB means that effluxes of NH 4 + and NO 3 -may be drastically reduced or even reversed in the light (Sundbäck et al. 1991, Cabrita & Brotas 2000, Magalhaes et al. 2002. In addition, MPB have been found to compete effectively with nitrifying/denitrifying bacteria for NH 4 + and NO 3 -. Assimilation:denitrification ratios of between 2 and 10 have been reported for eutrophic mudflats, whilst ratios of between 7 and >100 have been reported for more oligotrophic sediments (Cabrita & Brotas 2000, Dong et al. 2000. Furthermore, MBP have also recently been shown to have a significant negative impact on denitrification, most probably via competition for nitrogen (Risgaard-Petersen 2003). These findings are significant, as they suggest that a far greater proportion of nitrogen remineralised within the sediments will be assimilated rather than denitrified, resulting in a retention of bioavailable nitrogen within the system. Recen...

show abstract

Sediment—water exchanges of ammonium and phosphate in intertidal and subtidal areas of a mesotidal coastal lagoon (Ria Formosa)

Cited by 24 publications

References 36 publications

Exchange of nutrients across the sediment–water interface in intertidal ria systems (SW Europe)

Exchange of nutrients across the sediment–water interface in intertidal ria systems (SW Europe)

Biogeochemical modelling of Ria Formosa (South Portugal)

Carbon and nitrogen cycling on intertidal mudflats of a temperate Australian estuary. II. Nitrogen cycling

Contact Info

Product

Resources

About