Importance of benthic productivity in controlling the flux of dissolved inorganic nitrogen through the sediment-water interface in a hypertrophic marine ecosystem

Krom,

doi:10.3354/meps078163

Cited by 28 publications

(10 citation statements)

References 14 publications

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“…However, the NH4 flux was smaller than the flux from eutrophied sediments of the Bay of Fundy. Canada (Anderson 1986), and a hypertrophic fish pond in Israel (Krom 1991). The results indicating a recovery from sewage pollution are also supported by concentrations of NH, which are within the range observed for the Strait of Georgia (Clifford et al 1992).…”

Section: Nutrient Sourcessupporting

confidence: 61%

Influences of flood and ebb tides on nutrient fluxes and chlorophyll on an intertidal flat

Yin¹,

Harrison²

2000

Mar. Ecol. Prog. Ser.

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Intertidal estuarine sediment processes produce organics and nutrients and are influenced by river outflow and tidal cycles. Hence the sediments act as a source or sink of nutrients into or out of the water column. In most studies, a chamber incubation approach is used to study fluxes of nutrients into and out of the sediment; the chamber isolates the sediments from the hydrodynamics occurring in the overlying water column. Therefore, field data over an entire intertidal flat are lacking. Here, we present a unique case in which an intertidal flat is semi-enclosed, usually inundated for 12 to 14 h during a tidal cycle, and hence can be treated like an incubation chamber during this period of submergence. The intertidal flat on Sturgeon Bank, British Columbia, was directly exposed to domestic sewage effluents from the Iona Sewage Treatment Plant between 1967 and 1989. Since 1989, the sewage effluent has been &verted and discharged into deep water in the Strait of Georgia. The objective of the present study was to determine the effects of tidal cycles on the flux of nutrients from the sediment into the water column. We expanded the spatial scale of our study site by treating the semienclosed tidal flat as a large natural incubation chamber during the 12 to 14 h period of submergence. Water samples at 10 stations covenng Sturgeon Bank were taken during late flood tides and middle ebb tides, 12 to 13 h later. Salinity, temperature, chl a, nutrients (NH,, NO3 and PO,), suspended load, and particulate carbon (PC) and nitrogen (PN) at the surface were measured or analyzed. Based on nearly 2 yr observation between 1994 and 1995, we found that water coming onto Sturgeon Bank was a mixture of different origins since salinity was not correlated with temperature or any other variables except for particulate C/N. Chl a was higher during flood tides than during ebb tides, indicating a loss of chl a from the water column, likely due to feeding by benthic organisms. Ammonium concentrations were almost always higher during ebb tides than flood tides, indicating a release of NH, from the sediment. Therefore, the intertidal flat of Sturgeon Bank appears to be a sink for chl a and a source of NH, to the Strait of Georgia. Particulate C/N ratios were always higher than 7, indicating a predominantly terrestrial origin of particulate organics. Particulate C/N ratios were also found to be higher during ebb tides than flood tides, indicating preferential utilization of PN when organic matter was deposited onto the sedunent. Our study has shown that it is possible to treat an intertidal flat as an incubation chamber and follow fluxes of nutrients and particulates into and out of the water column during flood and ebb tides. With this approach, we concluded from NH4 concentrations and fluxes that the intertidal flat at Sturgeon Bank showed no signs of eutrophication due to previous sewage effluent contamination.

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Section: Nutrient Sourcessupporting

confidence: 61%

Influences of flood and ebb tides on nutrient fluxes and chlorophyll on an intertidal flat

Yin¹,

Harrison²

2000

Mar. Ecol. Prog. Ser.

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“…This 'filter' function is linked to at least 2 algal processes, algal assimilation of nutrients and photosynthetic oxygenation of the sediment surface, and has since then been shown in several studies (e.g. Krom 1991, Rizzo et al 1992, Wiltshire 1992, Risgaard-Petersen et al 1994, Reay et al 1995, van Luijn et al 1995, Sigmon & Cahoon 1997.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen fluxes, denitrification and the role of microphytobenthos in microtidal shallow-water sediments:an annual study

Sundbäck¹,

Miles²,

Göransson³

2000

Mar. Ecol. Prog. Ser.

219

135

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The annual cycle of oxygen and nitrogen flux, denitrification and microphytobenthic variables (primary production, biomass, composition and calculated N demand) were studied for 2 shallow-water microtidal sediment sites in NE Kattegat, 1 sandy and 1 silty, by incubating undisturbed sediment in the laboratory in light and darkness. Both sites (2 stations within each) were characterised by low concentrations of inorganic nitrogen (IN), in the overlying water during summer (NO3 generally < l pM), with winter concentrations of 5 and 30 pM for the sandy and silty site, respectively. Through the activity of microphytobenthos, the sediment systems appeared to be net autotrophic during most of the year. Net oxygen production varied between -400 and 6600 pm01 m-? h-', being highest during the warmest season. Although the composition of the microphytobenthos depended on the sediment type, it did not have a crucial effect on the magnitude of the microphytobenthic biomass or function. The .temporal pattern of the function of the microalgal community, on the other hand, was significantly influenced by the sediment type; sandy sediment exhibited a smooth seasonality, controlled mainly by temperature and light, while the silty microtidal sediment was also controlled by stochastic events, such as sediment resuspension. Microphytobenthos had a significant effect on the IN flux, the clearest effect being found for NH4. Total denitrification (isotope-pairing technique) generally varied between < l and 40 pm01 m-2 h-', being dominated by nitrification-coupled denitrification (D,,), and being 1 order of magnitude higher at the silty site. Microphytobenthic activity generally inhibited denitrification in the low-N areas in this study. The results suggest that the microphytobenthos functions as a major control throughout the annual cycle, by forming communities that are net photoautotrophic throughout the year, and by significantly influencing both the IN flux and denitrification rates. Sandy sediment appeared to function as an IN sink during winter and early spring, while no clear seasonal pattern was found for silty sediment. Calculated N demand of the microphytobenthos far exceeded the measured sediment net uptake of N, supporting the idea that sandy systems in low-nitrogen areas can be highly productive through a closed recycling of N. The ratio between calculated microphytobenthic N demand and measured denitrification rates suggests that denitrification has a minor role as a N sink, particularly in sandy, cold-climate microtidal sediments. MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser

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“…dsigmon@oce.orst edu are then available for direct uptake by planktonic and benthic autotrophs (Flint & Kamykowski 1984, Krom 1991. Regenerated nutrients may be intercepted by benthic autotrophs, decoupling the supply of nutrients to the pelagic ecosystem (Blackburn & Henriksen 1983, Sundback & Graneli 1988, Krom 1991. In addition to nitrogen and phosphorus, silicon has also been identified as a major, possibly limiting, nutrient for microalgal growth (Officer & Ryther 1980, Ragueneau et al 1994).…”

Section: Introductionmentioning

confidence: 99%

“…The breakdown of these particles releases organic and inorganic forms of nutrients that 'E-mail. dsigmon@oce.orst edu are then available for direct uptake by planktonic and benthic autotrophs (Flint & Kamykowski 1984, Krom 1991. Regenerated nutrients may be intercepted by benthic autotrophs, decoupling the supply of nutrients to the pelagic ecosystem (Blackburn & Henriksen 1983, Sundback & Graneli 1988, Krom 1991.…”

Section: Introductionmentioning

confidence: 99%

Comparative effects of benthic microalgae and phytoplankton on dissolved silica fluxes

De¹,

Lb²

1997

Aquat. Microb. Ecol.

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Microalgal effects on dissolved silica fluxes in an estuarine sandflat were investigated over an annual cycle. Benthic microalgal and phytoplankton chlorophyll a were measured at 17 times in Masonboro Sound, NC, USA, between June 1994 and May 1995. Using light and dark benthic chambers, dissolved silica (DSi) concentrations were measured in situ and used to calculate flux rates. Mean annual biomass was 64.6 and 10.0 mg chl a m-' for benthic microalgae and phytoplankton, respectively. Benthic microalgae and phytoplankton (both containing diatoms), alid cultured benthic diatoms were used to calculate Si:chl a weight ratios. Ratios of Si:chl a showed that benthic microalgae contain more silica per unit chlorophyll than phytoplankton, with mean Sl.chl a ratios of 14.3, 10.9, and 2.8:1, for benthic microalgae, cultured benthic diatoms, and phytoplankton, respectively. DSi flux rates were always higher in the dark, while some negative flux rates (into the sediment) were seen in the light. DSi flux rates averaged 81.0 pm01 m-' h-' in the dark and 37.0 pm01 m-' h-' in the light. Lab and field experiments showed that benthic microalgae can take up water column DSi, while typical phytoplankton concentrations exert little control of water column DSi. Temperature was found to be the major regulator of DSi fluxes, with flux rates decreasing with decreasing temperature. Benthic microalgae were significant regulators of light chamber DSi flux at temperatures <2O0C. Due to benthic microalgal uptake and low water column DSi concentrations observed under lower temperatures, nutnent limitation expenments were performed to determine if phytoplankton were silicate-limited. Of the 3 major nutrients. nitrogen, phosphorus, and silicon, only silicon was limiting for phytoplankton growth in every experiment. Benthic microalgae are important regulators of DSi flux, and can regulate water column DSi concentratlons for at least half of the year, possibly limiting phytoplankton growth and species composition in shallow, coastal environments.

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Importance of benthic productivity in controlling the flux of dissolved inorganic nitrogen through the sediment-water interface in a hypertrophic marine ecosystem

Cited by 28 publications

References 14 publications

Influences of flood and ebb tides on nutrient fluxes and chlorophyll on an intertidal flat

Influences of flood and ebb tides on nutrient fluxes and chlorophyll on an intertidal flat

Nitrogen fluxes, denitrification and the role of microphytobenthos in microtidal shallow-water sediments:an annual study

Comparative effects of benthic microalgae and phytoplankton on dissolved silica fluxes

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