The dominant processes of sediment distribution and focusing in a small, eutrophic, monomictic lake

Hilton, J.; Lishman, J.P.; Allen, P. V.

doi:10.4319/lo.1986.31.1.0125

Cited by 176 publications

(111 citation statements)

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“…During permanent deposition from the source to the bottom of the lake, sedimentary organic matter is influenced by a variety of factors including river inputs, underwater topography, and lake wind and induced waves, which eventually leads to different spatial distribution patterns [19][20][21][22][23][45][46][47]. In some small lakes, the spatial distribution of sedimentary organic matter is relatively simple, owing to one factor showing the greatest effect [48].…”

Section: Influence Factors and Paleolimnological Significancementioning

confidence: 99%

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

et al. 2012

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In this study, 67 surface sediment samples collected from Nam Co in central Tibet were analyzed for total carbon, total organic carbon and total nitrogen, and 51 of these samples were also analyzed for n-alkanes. The origin and spatial distribution of organic matter were then investigated using these proxies, and the control factors responsible for the spatial distribution patterns and paleolimnological significance were discussed. The results indicated that the origin of organic matter in surface sediment of Nam Co is consistent with the sources of n-alkanes, which were primarily submerged plants, followed by terrestrial plants, and then aquatic algae and bacteria. The organic matter in surface sediments of the lake showed typical spatial variability. Because of the great influence of underwater topography, river inputs and water quality, the spatial distribution of organic matter is enriched from the source to the deposit center. This spatial variability of organic matter in the lake indicates that the sediments in different areas have different sensitivities to environmental changes, which is important to reconstruction of paleoenvironments and paleoclimate using lake sediment cores.Tibetan Plateau, Nam Co, surface sediments, spatial distribution, sedimentary processes Citation:Wang Y, Zhu L P, Wang J B, et al. The spatial distribution and sedimentary processes of organic matter in surface sediments

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Section: Influence Factors and Paleolimnological Significancementioning

confidence: 99%

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

et al. 2012

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“…Not all of the four sediment focusing mechanisms identified by Hilton et al (1986a) are relevant to Llyn Conwy. Given that this lake is oligotrophic, hosts virtually no aquatic macrophytes and has extremely low turbidity and nutrient loadings, the organic degradation mechanism can be readily discounted here.…”

Section: Evaluation Of Alternative Sediment Focusing Mechanismsmentioning

confidence: 99%

“…An early application of seismic stratigraphic survey by Cronin et al (1993) to another small upland lake in Wales found limited evidence for slumping of highly organic sediments on slopes of about 15 degrees (26%) and it would be interesting to undertake bed imaging (e.g., using sidescan sonar) in Llyn Conwy to investigate the prevalence of slides and slumps. Hilton et al (1986a) also describe a process that they term "intermittent complete mixing," driven by widespread resuspension, mixing, and settling. This leads to sediment focusing by virtue of the greater water column sediment mass in deeper water.…”

Section: Evaluation Of Alternative Sediment Focusing Mechanismsmentioning

confidence: 99%

“…The work of Hilton (1985) and Hilton et al (1986a) has been especially valuable in providing a conceptual framework for understanding sedimentation in small lakes. Hilton et al (1986a) identified 10 distinct mechanisms for sediment dispersal.…”

mentioning

confidence: 99%

“…Hilton et al (1986a) identified 10 distinct mechanisms for sediment dispersal. Four of these are potentially associated with sediment focusing: peripheral wave action; intermittent complete mixing; slumping and sliding; and organic degradation.…”

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Three‐dimensional hydrodynamic and sediment transport modeling to test the sediment focusing hypothesis in upland lakes

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et al. 2017

Limnology & Oceanography

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Palaeolimnological studies rely on assumptions regarding the distribution and completeness of lake deposits that are not always fully supported by observations. In particular, the assumption that "focusing" of suspended sediments leads to preferential deposition in the deepest part of a lake is not always justified, especially in upland lakes subject to energetic wind forcing. Few studies have investigated the hydrodynamic controls on lake sediment focusing, especially the importance of wind-driven currents in deep water. We combine a three-dimensional numerical hydrodynamic and suspended sediment model (FVCOM) with a semi-empirical wind wave model to investigate the potential mobility of bottom sediments in a small oligotrophic upland lake (Llyn Conwy, north Wales, UK). Exploratory simulations of wave-and current-generated bottom stress and suspended sediment dynamics confirm the expected importance of wave-generated bottom stresses in shallower waters (< 3 m depth) around the shore. Field survey shows that lake sediments are largely absent from this zone. This is consistent with peripheral wave action as a sediment focusing mechanism. In deeper water, wind-driven currents become the dominant contributor to bottom stress. Strong wind forcing events drive an energetic circulation with peak bottom stresses that intermittently exceed any realistic erosion threshold over a large proportion of the lake at depths far below those at which waves can be effective. The spatial distribution of lake sediments, and the completeness of the sediment record, is thus determined by a complex interaction between wind-driven circulation and bathymetry, rather than by bathymetry alone. Although our sediment dynamics simulations are purely exploratory, the results are consisted with survey results that show a patchy distribution of deep-water accumulation. Some implications of these results for the selection of sediment coring locations and the interpretation of sediment records are considered.

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Effects of historical land use on sediment yield from a lacustrine watershed in central Chile

Cisternas¹,

Araneda²,

Martínez³

et al. 2001

Earth Surf. Process. Landforms

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Sediment yield in the San Pedro Lake watershed, inferred from sedimentation in the lake, can be related to land use changes shown on aerial photographs taken during the period 1943-1994. In this watershed, which covers 4Á5 km 2 of mountainous terrain in San Pedro County, central Chile, the area of native forest species decreased from 70 per cent in 1943 to 13 per cent in 1994. During this same period, the area of pine plantations increased from 4 to 46 per cent. To study effects of these changes, we took a core from the centre of the lake and estimated sedimentation rates by 210 Pb dating, which we checked with 137 Cs and pine pollen. The results show that sedimentation rate ranged from 5 mg cm À2 a À1 in the late 1800s to 60 mg cm À2 a À1 in the late 1960s. These rates, together with assumptions about the production and delivery of the sediment, give corresponding figures for sediment yields with maximum values close to 1 t ha À1 a À1 . Sediment yield between 1955 and 1994 closely tracks the total land use change that can be detected, irrespective of land use type, on sets of aerial photographs taken four to 18 years apart. However, this measure of land use change, while convenient and successful as a predictor of historical erosion, may be unreliable because it probably excludes many changes that occurred in long intervals between successive photographs.

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The dominant processes of sediment distribution and focusing in a small, eutrophic, monomictic lake

Cited by 176 publications

References 28 publications

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

Three‐dimensional hydrodynamic and sediment transport modeling to test the sediment focusing hypothesis in upland lakes

Effects of historical land use on sediment yield from a lacustrine watershed in central Chile

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