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Identifying the source and abundance of sediment transported within tidal creeks is essential for studying the connectivity between coastal watersheds and estuaries. The fine-grained suspended sediment load (SSL) makes up a substantial portion of the total sediment load carried within an estuarine system and efficient sampling of the SSL is critical to our understanding of nutrient and contaminant transport, anthropogenic influence, and the effects of climate. Unfortunately, traditional methods of sampling the SSL, including instantaneous measurements and automatic samplers, can be labor intensive, expensive and often yield insufficient mass for comprehensive geochemical analysis. In estuaries this issue is even more pronounced due to bi-directional tidal flow. This study tests the efficacy of a time-integrated mass sediment sampler (TIMS) design, originally developed for uni-directional flow within the fluvial environment, modified in this work for implementation the tidal environment under bi-directional flow conditions. Our new TIMS design utilizes an ‘L’ shaped outflow tube to prevent backflow, and when deployed in mirrored pairs, each sampler collects sediment uniquely in one direction of tidal flow. Laboratory flume experiments using dye and particle image velocimetry (PIV) were used to characterize the flow within the sampler, specifically, to quantify the settling velocities and identify stagnation points. Further laboratory tests of sediment indicate that bidirectional TIMS capture up to 96% of incoming SSL across a range of flow velocities (0.3–0.6 m s −1 ). The modified TIMS design was tested in the field at two distinct sampling locations within the tidal zone. Single-time point suspended sediment samples were collected at high and low tide and compared to time-integrated suspended sediment samples collected by the bi-directional TIMS over the same four-day period. Particle-size composition from the bi-directional TIMS were representative of the array of single time point samples, but yielded greater mass, representative of flow and sediment-concentration conditions at the site throughout the deployment period. This work proves the efficacy of the modified bi-directional TIMS design, offering a novel tool for collection of suspended sediment in the tidally-dominated portion of the watershed. [ABSTRACT FROM AUTHOR]

Shallow water environments are often difficult ones from which to recover undisturbed sediment cores, lending themselves to neither deep water sampling, nor techniques employed for wetland areas. The most simple and obvious way to obtain a core in water depths of less than 2 m is to drive a core tube directly into the sediments using some form of push rod or a percussion (hammer) device. A core driven by percussive methods, however, may be difficult to recover and sealing the tube may be problematic for retention of the sample. Here we describe a simple coring device designed for shallow water operation. The design contains elements of both deeper water gravity and directly driven push rod coring equipment. The device can recover cores up to about 1 m in length in water depths up to about 3-4 m deep. The sampling device has been tested over a number of years from diverse limnological settings (high and mid-Arctic lakes, temperate lakes) with consistently satisfactory results. [ABSTRACT FROM AUTHOR]

A testemunhagem por vibração ("vibracoring") tem se mostrado como um método eficaz na amostragem de sedimentos inconsolidados. Com o intuito de facilitar a portabilidade e reduzir o peso do equipamento, foi desenvolvido um testemunhador a vibração ("vibracorer") a partir de um motor de roçadeira costal adaptado. Os resultados alcançados demonstram as vantagens do aparelho desenvolvido, mesmo quando de sua utilização em áreas submersas.Vibracoring has been described as an efficient method for the sampling of unconsolidated sediments. In order to improve portability as well as reduce weight, a vibracorer was developed from a brush cutter, with some adaptations. The results show the advantages of the model, even for its use in offshore areas.