Effects of aeration, sediment grain size and burial on stream litter breakdown and consumer performance: a microcosm study

2017 ◽  
Vol 68 (12) ◽  
pp. 2266 ◽  
Author(s):  
Olatz Pereda ◽  
Maite Arroita ◽  
Ibon Aristi ◽  
Lorea Flores ◽  
Aitor Larrañaga ◽  
...  
Keyword(s):  
Grain Size ◽  
Hyporheic Zone ◽  
Food Resource ◽  
Low Flow ◽  
Sediment Grain Size ◽  
Water Abstraction ◽  
Fine Sediments ◽  
Sediment Size ◽  
Microcosm Study ◽  
Laboratory Microcosm

Turbulence and aeration are reduced in many streams during low-flow periods as a consequence of drought or water abstraction, thus affecting invertebrate interactions and pivotal ecosystem processes such as the breakdown of organic matter (OM). These effects can be larger in the hyporheic zone (HZ), the ecotone connecting the surface stream and groundwater, especially when fine sediments reduce hydraulic conductivity. In addition, OM breakdown in the HZ could depend on the availability of OM in the benthic zone (BZ), because the latter would not only be a more accessible, and thus preferred, food resource, but also more easily scoured downstream. In a laboratory microcosm experiment of 28 days duration, we manipulated aeration, sediment size and location of OM (either all buried or half buried with half on the surface, simulating the HZ and BZ respectively). Six mayfly (Habroleptoides) individuals and four stonefly (Capnioneura) individuals were enclosed in each microcosm and the consumption of OM was measured. Lack of aeration reduced oxygen saturation from 94 to 66%, reducing OM consumption particularly on the surface, in contrast with our expectations. As hypothesised, the availability of surface OM significantly reduced invertebrate consumption of buried OM. Habroleptoides performed better than Capnioneura, especially in fine sediments. The results suggest that reduced turbulence can affect invertebrate trophic interactions as well as the decomposition of OM, depending on sediment grain size and the location of OM.

Late Holocene Lake Sedimentology and Climate Change in Southern Alberta, Canada

1998 ◽  
Vol 49 (1) ◽  
pp. 96-101 ◽  
Author(s):  
Celina Campbell
Keyword(s):  
Grain Size ◽  
Ice Age ◽  
Low Flow ◽  
Sediment Grain Size ◽  
High Discharge ◽  
Climate Fluctuations ◽  
Fine Grained ◽  
Fine Sediments ◽  
Southern Alberta ◽  
Paleoclimate Proxy

Climatic changes in southern Alberta, Canada, for the past 4000 yr are reflected in a high-resolution record of lake sediment grain size. The proposed mechanism for this response is that outflow discharge removes fine-grained sediments, but increasingly fine sediments are retained and deposited as streamflow declines. At the same time, coarse sediments are brought in by high discharge entering the lake. The net effect of these two processes is to leave coarse, clay-deficient sediments during times of high streamflow and clay-rich sediments during times of low flow. The grain-size record from Pine Lake reflects historic climate fluctuations, as well as prehistoric fluctuations including the Little Ice Age and the Medieval Warm Period. Grain size at this site provides a simple, economical, and nonbiologically mediated paleoclimate proxy.

scholarly journals Universal relation with regime transition for sediment transport in fine-grained rivers

2019 ◽  
Vol 117 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Hongbo Ma ◽  
Jeffrey A. Nittrouer ◽  
Baosheng Wu ◽  
Michael P. Lamb ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sediment Load ◽  
Yellow River ◽  
Fine Sand ◽  
Sediment Flux ◽  
Universal Relation ◽  
Sediment Grain Size ◽  
Fine Grained ◽  
Predictive Algorithm ◽  
Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

scholarly journals Patterns of grain-size temporal variation of sediment transported by overland flow associated with moving storms: interpreting soil flume experiments

2011 ◽  
Vol 11 (9) ◽  
pp. 2605-2615 ◽  
Author(s):  
J. L. M. P. de Lima ◽  
P. A. Dinis ◽  
C. S. Souza ◽  
M. I. P. de Lima ◽  
P. P. Cunha ◽  
...  
Keyword(s):  
Grain Size ◽  
Overland Flow ◽  
Strong Relationship ◽  
Flume Experiments ◽  
Sediment Grain Size ◽  
Sediment Yields ◽  
Sediment Size ◽  
Size Evolution ◽  
Mean Grain Size ◽  
Recession Limb

Abstract. This study describes and interprets the evolution of grain-size distribution of sediment yields generated in an experimental soil flume subjected to downstream and upstream moving rain storms. Results of laboratory experiments show that downstream moving storms cause more soil loss than do upstream moving storms. The pattern of sediment grain-size evolution in time during a runoff event exhibits a clear dependence on the direction of storm movement. A strong relationship between overland flow discharge and mean sediment size is found. Nevertheless, the mean grain-size of sediments transported during the rising limb of the hydrograph is coarser than during the recession limb of the hydrograph. This is more marked for downstream moving storms.

scholarly journals Variability of suspended sediment grain size distribution in winter floods

2016 ◽  
Vol 48 (2) ◽  
pp. 141-151
Author(s):  
Agnieszka Hejduk ◽  
Leszek Hejduk
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Standard Deviation ◽  
Size Distribution ◽  
Suspended Sediment ◽  
Grain Size Distribution ◽  
Sediment Grain Size ◽  
Mean Values ◽  
Average Value ◽  
Sediment Size

Abstract Variability of suspended sediment grain size distribution in winter floods. The work presents the results of research concern variability of suspended sediment grain size, transported during the winter floods in agricultural catchment, in the period of hydrological years 2012-2015. The information about grain size distribution from nine winter flood events were collected over the study period, which allowed to analyze the variability of suspended sediment particle size during the various events. Grain size of sediment was determined using a laser particle size analyzer Mastersizer Microplus from Malvern Instruments Ltd. Variability of individual particle size classes were observed in each flood. Sand fraction dominated in seven of nine measured events. There was no significant increase of suspended sediment size in relation to the maximum of discharge. It can be explain by a relatively low discharge of recorded events. The percentage of material classified as clay (<4 μm) ranged from 0.08 to 1.01%, silt-sized material (>4 and <63 μm) ranged between 9.31 and 67.17% and sand-size material (>63 μm) ranged from 32.01 to 90.61%. The relationship between the particle size and the discharge requires further studies. The diameter d10, d50 and d90 and a standard deviation were calculated for each flood. Mean values of d50 for individual flood ranged between 41.05 and 191.32 μm with average value of 99.01 μm and average standard deviation of 32.57.

scholarly journals Characterizing the Relationship between the Sediment Grain Size and the Shoreline Variability Defined from Sentinel-2 Derived Shorelines

2021 ◽  
Vol 13 (14) ◽  
pp. 2829
Author(s):  
Carlos Cabezas-Rabadán ◽  
Josep E. Pardo-Pascual ◽  
Jesus Palomar-Vázquez
Keyword(s):  
Grain Size ◽  
Remote Sensing Data ◽  
Western Mediterranean ◽  
Fundamental Parameter ◽  
Numerical Function ◽  
Sediment Grain Size ◽  
Sediment Size ◽  
Definition Of ◽  
The Relationship ◽  
Sentinel 2

Sediment grain size is a fundamental parameter conditioning beach-face morphology and shoreline changes. From remote sensing data, an efficient definition of the shoreline position as the water–land interface may allow studying the geomorphological characteristics of the beaches. In this work, shoreline variability is defined by extracting a set of Satellite Derived Shorelines (SDS) covering about three and a half years. SDS are defined from Sentinel 2 imagery with high accuracy (about 3 m RMSE) using SHOREX. The variability is related to a large dataset of grain-size samples from the micro-tidal beaches at the Gulf of Valencia (Western Mediterranean). Both parameters present an inverse and non-linear relationship probably controlled by the beach-face slope. High shoreline variability appears associated with fine sands, followed by a rapid decrease (shifting point about medium/coarse sand) and subsequent small depletions as grain sizes increases. The relationship between both parameters is accurately described by a numerical function (R2 about 0.70) when considering samples at 137 open beaches. The definition of the variability is addressed employing different proxies, coastal segment lengths, and quantity of SDS under diverse oceanographic conditions, allowing to examine the effect they have on the relation with the sediment size. The relationship explored in this work improves the understanding of the mutual connection between sediment size, beach-face slope, and shoreline variability, and it may set up the basis for a rough estimation of sediment grain size from satellite optical imagery.

scholarly journals EXPLORING THE INFLUENCE OF LAND RECLAMATION ON SEDIMENT GRAIN SIZE DISTRIBUTION ON TIDAL FLATS: A NUMERICAL STUDY

2018 ◽  
pp. 85
Author(s):  
Lei Chen ◽  
Zeng Zhou ◽  
Mengpiao Xu ◽  
Fan Xu ◽  
Jianfeng Tao ◽  
...  
Keyword(s):  
Grain Size ◽  
Tidal Flat ◽  
Land Reclamation ◽  
State Of The Art ◽  
Numerical Study ◽  
Morphological Evolution ◽  
Sediment Grain Size ◽  
Fine Sediments ◽  
Sediment Sorting ◽  
Flat Profile

We explore the effects of land reclamation on the morphological evolution and sediment sorting on a tidal flat using a state-of-the-art numerical model (Delft3D). Consistent with existing field observations and analytical theories, model results indicate that the longitudinal profile adjusts itself converging to new equilibrium states (narrower and steeper) after a series of reclamations. Relatively fine sediments deposit adjacent to the sea dike, due to the flood-dominated tidal hydrodynamics. The amount of sediment deposition in front of the dike peaks when the dike is designed at mean sea level. After sequential reclamations, sediment grain size appears to be coarser offshore and on the tidal flat. Overall, this study suggests that land reclamation can lead to the readjustment of tidal flat profile shapes and coarsening of sediment grain size, which should be taken into account when reclamation projects are planned.

scholarly journals Centennial Impacts of the East Asian Summer Monsoon on Holocene Deltaic Evolution of the Huanghe River, China

2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi
Keyword(s):  
Grain Size ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
River Delta ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
The Huanghe River

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.

scholarly journals Water Temperature and Hydrological Modelling in the Context of Environmental Flows and Future Climate Change: Case Study of the Wilmot River (Canada)

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2101
Author(s):  
Christian Charron ◽  
André St-Hilaire ◽  
Taha B.M.J. Ouarda ◽  
Michael R. van den Heuvel
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Environmental Flows ◽  
Low Flow ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Water Abstraction ◽  
Surface Water Flow ◽  
Modelling Studies ◽  
Rcp 8.5

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

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