Littoral vs profundal components of sediment accumulation: Contrasting roles as phosphorus sinks

Moeller, R. P.; Wetzel, Robert G.

doi:10.1080/03680770.1987.11897952

Cited by 14 publications

(13 citation statements)

References 17 publications

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“…On a mass percent basis, the solid fraction includes -5% organic carbon, 50% C032-, and 0.04% total P (Moeller and Wetzel 1988;Carlton unpubl. ;Moeller pers.…”

Section: Resultsmentioning

confidence: 99%

Phosphorus flux from lake sediments: Effect of epipelic algal oxygen production

Carlton

Wetzel

1988

Limnology & Oceanography

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229

114

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Previous studies utilizing oxygen-sensitive microelectrodes have demonstrated that as a result of epipelic algal photosynthesis and microbial metabolism, and regardless of the oxygen concentration of the overlying water, sediments within the euphotic zone of lakes undergo marked diel fluctuations in the extent of oxygen penetration. This investigation utilized oxygen-sensitive microelcctrodes, 32P0,3-radiotracer, and a novel flow-through system to examine the effect of epipelic algal photosynthesis on sediment oxygen dynamics and the concomitant pattern of phosphorus release from lake sediments. Epipelic algae mediated release of phosphorus from sediments to overlying water via daily formation and breakdown ofthe oxidized microzone. During illumination, surficial sediments rapidly became oxygenated, and release of phosphorus diffusing from deeper sediment layers was inhibited. During darkness the microzone became anoxic, and phosphorus was released to overlying water at an accelerated rate, producing marked diel fluctuation in efflux rate. Observed patterns of release are consistent with recent evidence for a mechanism consisting of rapid uptake or rclcase of dissolved phosphate by sediment microorganisms in response to respective oxic or anoxic conditions. Microbial metabolism in aquatic sediments regenerates inorganic phosphate that accumulates in interstitial water and forms concentration gradients. Subsequent diffusive transport to overlying water can be retarded by a number of processes that either temporarily or permanently immobilize phosphate. Mortimer (1941Mortimer ( , 1942 demonstrated that the presence of an oxidized microzone at the sediment surface inhibited phosphorus release but that a decrease in redox potential of the microzone following the onset of anoxic conditions in the overlying water stimulated the reduction of Fe(III), thus releasing phosphate bound in hydrous oxides and gels at the sediment surface. This key role of oxygen has been substantiated in numerous studies in various lake and sediment types @Lamp-Nielsen 1974;Patrick and Khalid 1974;Frevert 1980). Also identified as factors affecting the rate of P flux from sediments are pH, tem-

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“…On a mass percent basis, the solid fraction includes -5% organic carbon, 50% C032-, and 0.04% total P (Moeller and Wetzel 1988;Carlton unpubl. ;Moeller pers.…”

Section: Resultsmentioning

confidence: 99%

Phosphorus flux from lake sediments: Effect of epipelic algal oxygen production

Carlton

Wetzel

1988

Limnology & Oceanography

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229

114

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“…Hikanson, 1983;Godshalk & Wetzel, 1984). Interception of particulate organic matter from both inlet and diffusive runoff within emergent and submersed littoral vegetation is major and results in rapid, accelerated deposition (e.g., Lundqvist, 1927;Godshalk & Wetzel, 1984;Moeller & Wetzel, 1988). Beyond the submersed vegetation at greater depths, an erosional zone is common in lacustrine ecosystems depending on the depths to which surficial mixing occurs.…”

Section: Processing Of Organic Matter In Wetland and Littoral Zonesmentioning

confidence: 99%

Gradient-dominated ecosystems: sources and regulatory functions of dissolved organic matter in freshwater ecosystems

1992

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The emergent wetland and littoral components of the land-water zone are functionally coupled by the amounts and types of dissolved organic matter that are released, processed, transported to, and then further processed within the recipient waters. Operational couplings and integrations in freshwater ecosystems occur along physical and metabolic gradients of a number of scales from micrometer to kilometer dimensions. The operation and turnover of the microbial communities, largely associated with surfaces, generate the metabolic foundations for material fluxes along larger-scale gradients.Because of the predominance of small, shallow freshwater bodies, most dissolved organic carbon (DOC) of lacustrine and riverine ecosystems is derived from photosynthesis of higher plants and microflora associated with detritus, including sediments, and is only augmented by photosynthesis of phytoplankton. As the dissolved organic compounds generated in the wetland and littoral interface regions move toward the open-water regions of the ecosystems, partial utilization effects a selective increase in organic recalcitrance. Even though DOC from allochthonous and from interface sources is more recalcitrant than that produced by planktonic microflora, decomposition of the much larger interface quantities imported to the pelagic zone dominates ecosystem decomposition. The observed high sustained productivity of the land-water interface zone results from extensive recycling of essential resources (nutrients, inorganic carbon) and conservation mechanisms. On the average in lakes and streams, greater than 90 percent of the decomposition in the ecosystem is by bacteria utilizing DOM from non-pelagic sources of primary productivity. In addition to direct mineralization of DOC from non-pelagic sources, many of the organic compounds function indirectly to influence metabolism. New evidence is presented to demonstrate formation of complexes between humic and fulvic organic acids and extracellular enzymes. These complexes inhibit enzyme activity and can be transported within the ecosystem. The complex can be decoupled by mild ultraviolet photolysis with regeneration of enzyme activity in displaced locations.

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“…Long-term sediment-accumulation rates measured over periods of decades to centuries are therefore high within the low-turbulence vegetated littoral zone, declining sharply to a minimum in the zone of highest turbulence beyond macrophyte beds, and rising to a second maximum in deeper profundal regions of lakes and reservoirs characterized by low turbulence (Moeller and Wetzel 1988;James and Barko 1990). The role of macrophyte beds in long-term sediment accumulation and retention was dramatically demonstrated during the eutrophication of Lake Constance when an increase in algal turbidity lead to the disappearance of beds, and the loss of the extensive sediment shelves deposited over centuries, as the result of increased nearshore turbulence (Schröder 1988).…”

mentioning

confidence: 99%

“…Thus P, Fe, and Mn retention rates are 2-5 times higher in a Littorella uniflora bed than in nearby bare sediments (Christensen et al 1997). Furthermore, a high C : P ratio observed in littoral sediments (Moeller and Wetzel 1988) points to an incomplete microbial mineralization of the organic matter, shown directly by the presence of plant fragments in macrophyte bed sediments (LaZerte 1983).…”

mentioning

confidence: 99%

The role of submerged macrophyte beds in phosphorus and sediment accumulation in Lake Memphremagog, Quebec, Canada

Rooney

Kalff

Habel

2003

Limnology & Oceanography

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The relationships between long-term (ϳ115-year) phosphorus and sediment accumulation and submerged macrophyte biomass were determined both within a submerged macrophyte bed and among beds in Lake Memphremagog, Quebec, Canada. Strong relationships between present submerged macrophyte biomass and littoral-zone sediment and phosphorus accumulation rates both within and among macrophyte beds yielded simple models for estimating long-term littoral-zone accumulation rates. Mean sediment particle size at the depth of maximum submerged macrophyte biomass, estimated from water content, was comparable with the mean particle size in profundal zone of Lake Memphremagog, suggesting that energy environments differ little between vegetated littoral zones and profundal zones. The mean total sediment-accumulation rate of 1.2 mm yr Ϫ1 in the macrophyte beds was indistinguishable from average profundal rates of sediment accumulation in North American lakes. Although dense beds accumulated twice as much bulk sediment per unit area (g m Ϫ2 yr Ϫ1

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Littoral vs profundal components of sediment accumulation: Contrasting roles as phosphorus sinks

Cited by 14 publications

References 17 publications

Phosphorus flux from lake sediments: Effect of epipelic algal oxygen production

Phosphorus flux from lake sediments: Effect of epipelic algal oxygen production

Gradient-dominated ecosystems: sources and regulatory functions of dissolved organic matter in freshwater ecosystems

The role of submerged macrophyte beds in phosphorus and sediment accumulation in Lake Memphremagog, Quebec, Canada

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