High resolution measurements of sediment resuspension above an accumulation bottom in a stratified lake

Pierson, Donald C.; Weyhenmeyer, Gesa A.

doi:10.1007/bf00005730

Cited by 65 publications

(32 citation statements)

References 33 publications

(33 reference statements)

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“…2). During the period of stratification, direct wind/wave activities will not influence sediment resuspension in the hypolimnion, but internal seiche activities can cause sediment resuspension (Gloor et al 1994;Pierson and Weyhenmeyer 1994). Because it is not yet known how currents due to internal seiche activities differ quantitatively from currents due to direct wind/wave activities, the daily maximum horizontal current velocity was calculated in the same way during stratified as during unstratified periods.…”

Section: Acknowledgmentsmentioning

confidence: 99%

A validated model for daily variations in the flux, origin, and distribution of settling particles within lakes

Weyhenmeyer

Håkanson

Meili

1997

Limnology & Oceanography

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We performed intensive sediment trap studies at different water depths and locations in nine Swedish lakes to determine the flux, distribution, and origin of settling particulate matter in the pelagic zone. From these data, we developed a dynamic model that includes important mechanisms controlling fluxes of autochthonous, allochthonous, and resuspended particles in lakes during both stratification and turnover. The data suggest that during the period of turnover, sediment resuspension is a function of direct wind/wave activities. During these periods, resuspended particles are quite evenly distributed in the water column. During stratification, however, particles in deeper lakes are enriched in the hypolimnion. We suggest that these particles are resuspended due mainly to internal water motions. The model describes how much and at which water depths material is resuspended, and how this material is distributed in the water column. This includes the process of sediment focusing. The model allows determination of sediment accumulation at different water depths and of the boundary between erosion, transportation, and accumulation of sediment. Furthermore, the model shows the time dependence of the flux and distribution of settling particles in relation to changes in wind speed. The model is driven by wind, stratification, and lake morphometric data that can be determined with good accuracy. Some coefficients describing particle dynamics are also needed, e.g. particle settling velocity, vertical water mixing velocity, and sediment resuspension rate. The most uncertain coefficients were subjected to sensitivity analyses. The model can explain differences over time in the flux, origin, and distribution of settling particles in different lakes. Because it has earlier been recognized that the flux and distribution of settling particles can be of great importance for the dispersal, burial, biouptake, and ecological effects of nutrients and contaminants, the model may provide valuable information for lake management.Settling particles have often been considered to be the major transport media for nutrients, toxic metals, and organic contaminants, and they are known to be important for the removal of bioavailable nutrients and pollutants from the water column (Salomons and Forstner 1984;Allan 1986;Allard et al. 1991; Baudo et al. 1991). To determine spatial distribution patterns, sedimentation and resuspension, biological uptake, and ecological effects of nutrients and pollutants, information is needed about the flux of carrier particles, in particular about the amount, the composition, and the distribution of settling particulate matter (SPM; see notations). It is quite common to study characteristics of SPM with sediment traps (Eadie et al. 1984;Rosa 1985; Bloesch and Uehlinger 1986), and the processes of sediment distribution are well known (Hilton 1985; Hilton et al. 1986). Nevertheless, fluxes of SPM in lakes are not completely understood, most likely because there are still uncertainties in quantifying the ...

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Section: Acknowledgmentsmentioning

confidence: 99%

A validated model for daily variations in the flux, origin, and distribution of settling particles within lakes

Weyhenmeyer

Håkanson

Meili

1997

Limnology & Oceanography

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“…Seiche dissipation generates turbulence, which is responsible for mixing heat [Lorrai et al, 2011], sediments [Pierson and Weyhenmeyer, 1994], chemicals [MacIntyre and Jellison, 2001], organisms [Serra et al, 2007], and pollutants [Sorensen et al, 2004].…”

Section: Introductionmentioning

confidence: 99%

Vertical propagation of lakewide internal waves

Henderson¹,

Deemer²

2012

Geophysical Research Letters

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[1] Internal waves with diurnal period dominated velocities measured by an Acoustic Doppler Profiler (ADP) in a small lake (main basin 3000 m by 400 m by 18 m). ADP profiles and an along-lake temperature section indicate that the observed waves, like seiches, had horizontal wavelengths exceeding the metalimnion length. However, unlike non-dissipative seiches, the observed waves propagated vertically, carrying energy to the lakebed where waves were absorbed, rather than being strongly reflected. This absorption is predicted by a standard parameterization of boundary layer dissipation. The absence of upward-propagating energy precludes seiche resonance, limits focusing of waves toward attractors, and suggests that hypolimnion dissipation was limited by the supply of downward-propagating energy. Vertical wavelengths were less than the lake depth. Simplified calculations suggest that vertically-propagating waves, as opposed to vertically standing seiches, are most likely where vertical wavelengths are short, near-bed stratification is strong, and lakes are short and deep.

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“…Les teneurs en sels nutritifs montrent un épuisement des nitrates sur toute la colonne d'eau ( Fig.5A), en même temps qu'un enrichissement du milieu en éléments phosphores ( Fig.5B et C). En réalité, la faible profondeur de la colonne d'eau durant cette année sèche (Fig.2), associée aux vents quasi-permanents régnant au niveau de la retenue (Chergui), contribueraient en bonne partie à la resuspension des sédiments fortement enrichis en phosphore, et à l'enrichissement du compartiment aquatique en éléments phosphores (Piersen & Weyhenmeyer 1994, Derraz 1995. Parallèlement, et sous l'action des vents de direction Est (Chergui), les colonies «flottantes» de Microcystis forment des tapis étalés sur plusieurs hectares vers l'amont de la retenue, atteignant des valeurs maximales de 450 mgl" 1 .…”

Section: Dynamique Saisonnière De Quelques Espèces Dominantesunclassified

Dynamique du phytoplancton en relation avec certains paramètres physico-chimiques dans la retenue El Kansera (Maroc)

Berrada

Benzekri³

1999

Ann. Limnol. - Int. J. Lim.

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Mots-clés : phytoplancton, dynamique, cyanobactéries, diatomées, retenue de barrage. L'étude de la dynamique saisonnière du phytoplancton dans la retenue El Kansera a été réalisée dans le but de comprendre au mieux le phénomène d'eutrophisation de cet écosystème lacustre. La biomasse (exprimée en poids frais) a été suivie pendant un cycle et demi, d'avril 1995 à août 1996. Cette période étant marquée par la transition d'une année de sécheresse avec une année pluvieuse, la composition et la dynamique saisonnière des peuplements algaux est analysée en fonction des variables environnementales. En 1995, année de sécheresse, le peuplement algal est dominé par les cyanobactéries, en particulier Microcystis aeruginosa qui représente plus de 99 % de la biomasse algale totale. En 1996, année pluvieuse, le peuplement algal est plus diversifié et constitué d'une diatomée centrique (Cyclotella ocellata) et de Chlorococcales (Crucigenia apiculata, Scenedesmus ecornis, Oocystis lacustris...). La saison d'été est marquée en revanche par la recolonisation du milieu par M.aeruginosa. Les variables environnementales (climat, physico-chimie de l'eau et apports exogènes) semblent régir de près la succession phytoplanctonique dans la retenue El Kansera. Dynamics of phytoplankton and relationship with physical and chemical parameters in El Kansera lake-reservoir (Morroco)Keywords : phytoplankton, dynamics, cyanobacteria, diatoms, lake-reservoir.A study of the seasonal dynamics of the phytoplankton in the El Kansera lake-reservoir has been carried out in order to understand the eutrophication process of this lake. Biomass (wet weight) was monitored from April 1995 to August 1996. This period is characterised by the transition from a dry year to a rainy year. So, composition and dynamics of phytoplankton are analysed, and related to environmental factors. In 1995 cyanobacteria dominated the algal communities ; Microcystis aeruginosa represented more than 99 % of the total biomass. In 1996, phytoplankton was more diversified and constituted of a centric diatom (Cyclotella ocellata) and chlorococcals (Crucigenia apiculata, Scenedesmus ecornis, Oocystis lacustris...). In summer, M.aeruginosa appeared again and dominated the algal communities. Environmental factors (climate, water composition and exogenic inputs) seem to control appreciably the phytoplankton succession in El Kansera lake-reservoir.

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High resolution measurements of sediment resuspension above an accumulation bottom in a stratified lake

Cited by 65 publications

References 33 publications

A validated model for daily variations in the flux, origin, and distribution of settling particles within lakes

A validated model for daily variations in the flux, origin, and distribution of settling particles within lakes

Vertical propagation of lakewide internal waves

Dynamique du phytoplancton en relation avec certains paramètres physico-chimiques dans la retenue El Kansera (Maroc)

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