Fine Stream Sediments Research Articles

Short-term exposure to elevated suspended sediment increases oxygen uptake of gilled larval Eastern Hellbender (Cryptobranchus alleganiensis) salamanders

Freshwater ecosystems are increasingly impacted by anthropogenic elevated levels of suspended sediment that may negatively affect aquatic organisms, including salamanders. Although increasing fine sediment in streams has been suggested as a reason for population declines, to date no study has empirically assessed the effect of suspended sediment on gilled larval Eastern Hellbenders (Cryptobranchus alleganiensis (Sonnini de Manoncourt and Latreille, 1801)), a critical life-history stage and a species of conservation concern. We used custom respirometers to elucidate effects of suspended sediments on larval Eastern Hellbender oxygen uptake in trials conducted in situ in Georgia (USA) streams. Mean oxygen uptake increased and was significantly higher in trials when larval salamanders were exposed to suspended sediment (mean = 5.06 mg O2/L for 800 mg/L of sediment treatment vs. 2.25 mg O2/L for 0.00 mg/L of sediment control). This may indicate elevated physiological stress in response to short-term exposure to suspended sediments. Qualitatively, individuals in both groups exhibited rocking behavior in response to low oxygen (hypoxia), albeit at different frequencies (sediment exposure = 7.6 rocks/min and control = 2.1 rocks/min). Larval salamanders may be able to temporarily compensate for low oxygen through increased rocking behavior when high suspended sediment loads are present, with future respirometry research needed.

Mechanical Behavior of Fired-Clay Bricks from Stream Sediments under Uniaxial Compressive Loading

In the northeast of Thailand, raw material for fired-clay brick is obtained from fine stream sediments in the lower Nam Phong and upper Chi River sub-watersheds. Hundreds of brickyards exist along the waterway producing rice husk ash (RHA) bricks for construction. Technical study on the production of these bricks is limited, therefore, detailed studies on mechanical and chemical properties will enhance the understanding of the production process in order for further improvement. In this study, a preliminary investigation of the brickyards and production process was conducted. Brick samples as well as raw sediment materials were collected from 6 randomly selected locations for laboratory testing on physical, chemical, and mechanical properties. A total of 300 brick specimens were collected being 50 specimens from each location. The brick dimensions are roughly 5×5×15 cm with an average weight of about 680 g. X-Ray Diffractometry show that the fired brick composition is approximately 90-98% quartz, 5-7% clay minerals, and less than 1% minor minerals. Mechanical behavior of the fired-clay bricks was evaluated by compressive loading of single brick units conducted under dry and submerged (with reverse osmosis water) conditions. The compressive strength of the brick unit is found to be proportional to its density with values in the range of about 0.4-1.2 MPa. Bricks with RHA to sediment ratio of 1:3 exhibit a higher average strength that that of other ratios.

Applicable Fine Stream Sediments from Upper Chi River Produced Fired Clay Bricks

Stream sediments from the upper Chi River basin, including Chi and Nam Phong sub-watershed, are applicable to be a source of raw materials to produce fired clay bricks. The sampling locations of clay materials are generally found along the river terrace where are covering three different regions (upper-, mid-and lower sub-watershed) nearby brickyards. Quartz is the main mineral of all samples. Moreover, mainly clay mineral groups consist of mica, kaolinite, and chlorite group composing totally around 5%. Other mineral compositions, such as carbonate, evaporite, corundum, hematite and pyrolusite are normally found both in fine stream sediments and fired clay bricks. Additional minerals in fired bricks are forsterite, zircon and mullite group which are less than 0.2%. Their strength in submersion test expressed in the air-dried to pure water both 1 day and 5 days is revealed that their strength and strain intend to increase with the submersed brick. Besides, prism compressive strength decreases in half related to a fired brick unit. Their impact resistances are significantly distinctive by mineral composition of clay mineral group and silica. The compressive strength of air-dried fired brick at the ultimate stress and strain corresponding by time in water absorption test show that water filled in void or pore can enhance their strength and strain. Thus, fired clay bricks are capable to resist compressive force than the normal condition.

Evaluating habitat effects on population status: influence of habitat restoration on spring‐run Chinook salmon

Summary1. A key element of conservation planning is the extremely challenging task of estimating the likely effect of restoration actions on population status. To compare the relative benefits of typical habitat restoration actions on Pacific salmon (Oncorhynchus spp.), we modelled the response of an endangered Columbia River Chinook salmon (O. tshawytscha) population to changes in habitat characteristics either targeted for restoration or with the potential to be degraded.2. We applied a spatially explicit, multiple life stage, Beverton‐Holt model to evaluate how a set of habitat variables with an empirical influence on spring‐run Chinook salmon survivorship influenced fish population abundance, productivity, spatial structure and diversity. Using habitat condition scenarios – historical conditions and future conditions with restoration, no restoration, and degradation – we asked the following questions: (i) how is population status affected by alternative scenarios of habitat change, (ii) which individual habitat characteristics have the potential to substantially influence population status and (iii) which life stages have the largest impact on population status?3. The difference in population abundance and productivities resulting from changes in modelled habitat variables from the ‘historical’ to ‘current’ scenarios suggests that there is substantial potential for improving population status. Planned restoration actions directed toward modelled variables, however, produced only modest improvements.4. The model predicted that population status could be improved by additional restoration efforts directed toward further reductions in the percentage of fine sediments in the streambed, a factor that has a large influence on egg survival. Actions reducing fines were predicted to be especially effective outside the national forest that covers most of the basin. Scenarios that increased capacity by opening access to habitat in good condition also had a positive but smaller effect on spawner numbers.5. Degradation in habitat quality, particularly in percent fine sediments, within stream reaches located in the national forest had great potential to further reduce this population’s viability. This finding supports current forest planning efforts to minimise road density and clear‐cut harvests and to return forest stand structure in dry regions to the historical condition that promoted frequent low‐intensity fires rather than catastrophic stand‐replacing fires, as these landscape factors have been shown to influence percent fine sediment in streams.6. Together, these results suggest that planning focusing on protecting currently good habitat, reducing fine sediments to promote egg survival and increasing spawner capacity will be beneficial to endangered spring‐run Chinook population status.

STREAM INSECTS AS BIOINDICATORS OF FINE SEDIMENT

Fine inorganic sediment (≤ 2mm) is a major non-point source pollutant in streams. While some fine sediment in streams is natural, loads in human-impacted streams often exceed their capacity to flush these sediments during high flows. Regardless of the source, the negative effects of increased levels of fine sediment in streams are realized in all biotic components of stream ecosystems from microbes to fish and in functional components such as primary and secondary production and nutrient cycling. Bioindicators sensitive to these negative impacts would be a valuable tool for resource managers. We focus on aquatic insects and their usefulness as bioindicators of increased fine sediment in stream ecosystems. Aquatic biomonitoring typically is used in most stream monitoring protocols. One disadvantage of current applications of aquatic biomonitoring is that it does not allow one to discriminate among pollutants. To address this disadvantage we targeted a specific pollutant, fine inorganic sediment, and examined the relationship between fine inorganic sediment and aquatic insects. A biotic index to be used to detect and monitor changes in stream ecosystem health directly due to increases in fine inorganic sediments is necessary for resource managers as they work to maintain aquatic ecosystem biodiversity and productivity, as well as sustain economic growth. In this study, fine sediment and invertebrate data were analyzed from 562 stream segments from Idaho, Oregon, Washington, and Wyoming. From 661 invertebrate taxa a subset (n=83) of widely-occurring insects was used to develop the fine sediment bioassessment index (FSBI). We found that there are species- specific responses to the amount of fine sediment in the streambed. We also found that traditional metrics such as the ratio of Ephemeroptera (E), Plecoptera (P), Trichoptera (T) to Diptera (D) could not discriminate among streams with varying levels of fine sediment. To test the fine sediment index as a predictor of sediment levels, a subset of streams were scored with the FSBI using an independent data set collected by the Idaho Department of Environmental Quality from the eastern Snake River Basin/ High Desert ecoregion. Using the FSBI score for each stream the percent fine sediment in a the stream was predicted and then compared to the measured value (r 2

Lithogeochemical Prospecting Through Stream Sediments in Bela Ophiolite of Lasbela Area

Lithogeochemical investigation of sediments of active streams draining through Bela Ophiolite. from Lasbela area are presented. This area consists mainly of ophiolites associated with sedimentary rocks of Jurassic-Cretaceousa ge. Quantitative examinationso f important immobile ,elements such as Fe, Mn, Ti & Cr, and semi-mobile to mobile like Zn, Cu, Ni and Co have been carried out. These elements have anomalous concentrations in fine stream sediments in certain regions. An attempt is made to demarcate the areas of possible occurrences of ore mineralization associated with the Bela Ophiolite based on statistical analysis of the geochemical data.. Statistical analysis and plots of data were employed to evaluate the distribution and interrelationship of these elements and coefficient of variation and correlation coefficients were calculated. The suitability of the methods is discussed in relation with the arid climatic conditions of southern Balochistan and the local geology.

Correlations between mineralogical and chemical compositions of fine stream sediments: application to geochemical exploration in tropical rain forests, Bolívar State, Venezuela

In this work we have studied stream sediments that differ in hydrodynamic energy of depositional environments and in the lithologies of source areas. The first type consists of sediment sampled in stream channels in a relatively high energy environment (samples CS); the other type is from sediments deposited laterally, along margins of channels, where stream energy decreases (samples LS). Eighteen CS samples and 36 LS samples, sieved to 230 mesh, taken from streams and rivers that drain different lithologies, were analyzed for mineralogical and chemical compositions. Samples CS and LS have different chemical compositions, although they are composed of the same minerals. CS samples have low concentrations of absorbing phases (e.g., clay and Fe-Mn oxides), low total and extractable Cu, Co, Ni and Cr, and high zircon and quartz. Conversely, LS samples have greater abundances of absorbing phases, transition elements, and lower zircon and quartz. The sample types can be discriminated by compositional differences in Zr, Si and Al. Differences in proportions of minerals of the fine sediment samples (Fe-Mn oxides, clays, quartz and zircon) result from differences in source areas and hydrodynamic characteristics of depositional sites. It is difficult, if not impossible, to collect all samples from sites with exactly the same hydrodynamic conditions or from the same source area; it is therefore necessary to classify samples according to mineralogical compositions, and to know proportions of absorber phases, clays and oxides, to the inert phase, quartz, before interpretation.

New Technique for Measuring Fine Sediment in Streams

Abstract Techniques commonly used to measure fine-sediment accumulation in streambed gravels can be labor and equipment intensive. We evaluated the sediment trapping capabilities of modified Whitlock–Vibert boxes under both laboratory and field conditions and compared the accumulated fine sediment to that contained in adjacent gravels as indicated by McNeil core samples. Our results suggest the boxes can be used as an alternative to core sampling for monitoring intergravel fine sediment levels. Advantages include ease of transport to remote field sites, small sample volumes, and reduced analysis time. Problems encountered were displacement of boxes by flood and ice flows and inundation by large sediment spills.

The invertebrate fauna of a forest stream and its association with fine particulate matter

Abstract The invertebrate fauna colonising wooden blocks placed in a beech forest stream was studied over a period of 1 year. At least 31 species were taken during the course of the study, with 3 species of Chironomidae predominating numerically. Most species were associated principally with fine particulate matter (FPM) deposited on the upper surfaces of blocks, although a stonefly, Spaniocerca zelandica, was most abundant on the barer surfaces. Of the Chironomidae, Paucispinig‐era approximata and Polypedilum canum had clearly defined life history patterns with emergence from February to April and October to January, respectively. Psectrocladius sp. had a poorly defined life history. Gut contents of 16 insect species showed that 4 were predominantly predatory, and the remainder were detritivores. The latter could be categorised as shredders (large particle detritivores) or collector‐browsers which mainly ingested particles in the dominant (<50 μm) size range. Oxygen consumption by fine stream sediments was similar at different times of year which suggests that the food quality of detritus may tie relatively constant at all times.