Characteristics Of Suspended Particulate Matter Research Articles

Characterization of suspended particulate matter surrounding a salmonid net-pen in the Broughton Archipelago, British Columbia

region of the net-pen. Approximately 87% and 30% of the mean SPM were observed at depth and beside the net-pen, respectively, suggesting that transport of suspended particulates was predominantly in the vertical direction. Sediment trap deployments revealed that sedimentation fluxes of total SPM, carbon, and nitrogen were higher below the farm than at the control site located 500 m away. Major and minor elemental analyses of feed pellets and sediment trap contents showed that calcium, phosphorus, sulphur, and strontium were removed within the net-pen system. The feed-specific carbon isotope signature ( 13 C=21.4 to 22.0‰) was not evident in the trap samples deployed beside the bottom of the net-pen ( 13 C=23.4‰), suggesting the relative absence of feed pellet particles, isotopic alteration through fish assimilation and/or dilution of the isotope signature with other carbon sources. However, a feed-signature was evident in samples collected in the upper water column (depth 5 m), suggesting that 13 C might serve as a useful tracer of feed particles.

MORPHOLOGICAL AND CHEMICAL CHARACTERIZATION OF NEUTRALLY BUOYANT PLUME-DERIVED PARTICLES AT THE EASTERN MANUS BASIN HYDROTHERMAL FIELD, PAPUA NEW GUINEA

Neutrally buoyant particulate matter emitted from hydrothermal plumes in the eastern Manus Basin hydrothermal field, Papua New Guinea, was detected and sampled by CTD-transmissometer surveys during marine expeditions in 1991 and 1993. Characterization of suspended particulate matter has helped to prove that the main sources of venting are along a prominent 20km-long NE–SW-striking felsic volcanic ridge. Elemental composition and particle morphology were determined by scanning electron microscopy and X-ray energy-dispersion spectroscopy. The size distribution and relative abundance of particles were determined by image analysis on selected samples. By looking at the composition of particulate matter, we can infer the origin, maturity and proximity of the source that is producing the particles. Seven types of particles have been morphologically and chemically characterized: i) filaments of probable biogenic origin of a Mn–Fe–Si phase containing traces of Cu and Zn, ii) orblike particles of an Fe–Mn–Si phase containing minor Mg, Al, P, K and Ca, iii) barite, iv) anhydrite, v) colloidal-sized amorph ous iron oxide, vi) an unidentified Si–Fe-rich phase, and vii) widespread biogenic detritus (shrimps, diatoms, silicoflagellates, copepods and unidentified gelatinous organic matter). Most of the particles are <2 � m in size and range from <2 � m for amorphous iron oxide to 100 � m for anhydrite and the Si–Fe-rich phase. Studies on suspended particulate matter constitute an effective way to recognize hydrothermal plumes.

Compositional characterization of suspended particulate matter in hellenic volcanic arc hydrothermal centres

Suspended particulate matter (SPM) separated from waters discharging from a number of submarine hydrothermal vents at Palaeochori bay, Milos island was analysed for major and trace elements (i.e. Fe, Mn, Cu, Pb, Cd, Ca, Sr, Si, Al, B a).It was found that SPM in the hydrothermal waters investigated was strongly enriched in Fe, Mn, Si and Ba compared with normal Aegean Sea waters.Four major hydrothermal centres were distinguished on the basis of the SPM chemical characteristics. On average Fe decreases in the four hydrothermal centres in the following order : A > D > C > B while Si decreases as follows: D > A > C > B.Calcium, Sr, Si and Ba show a strong biogenic affiliation. The marked enrichment of these elements in hydrothermal centre D relative to the other hydrothermal centres indicates strong biological activity there.The diurnal variability of Ca, Sr, Si and Ba shows increase in the afternoon. On average the concentrations of Fe, Si and Ca were higher in September 1996 than in June 1996. By contrast Mn, Cu, Pb and Sr were more enriched in June than in September 96.

Quantifying the response of optical backscatter devices and transmissometers to variations in suspended particulate matter

Optical instruments have been used effectively in studies of sediment dynamics for several decades. Without accurate instrument calibrations, calculated concentrations of suspended particulate matter (SPM) may be unreliable, with implications for interpretations of sedimentary processes and sediment fluxes. This review aims to quantify the effect of variations in SPM characteristics on the response of optical instruments (optical backscatter sensors OBS and transmissometers) and to note the implications for users of these instruments. A number of factors have a significant impact on instrument response, for example; a change in grain size from medium sands to fine silts may lead to a×100 increase in instrument response; flocculation of fine particles may decrease instrument response by×2; and the presence of plankton in suspension may lead to poor instrument calibrations of SPM concentration. Calibrations carried out in environments either with multi-modal bottom sediments, where flocculation of fine-grained sediments is likely, or where the hydrodynamics or grain type are highly variable must also include a determination of the changing nature of the suspended load in space and time. A more complete understanding of instrument response to SPM and of calibration requirements may enable optical devices to be used to a greater potential as long-term measures of SPM concentration, and also enable improvements in calculations of net sediment fluxes.

Validation of a field filtration technique for characterization of suspended particulate matter from freshwater. Part I. Major elements

A field filtration method for the concentration and separation of suspended particulate matter (SPM) from freshwater systems for subsequent determination of major elements (Si, Al, Ca, Fe, Mn, Mg, Na, K, P, Ti and S) is validated with respect to precision and bias. The validation comprises the whole procedure including filtration, sample digestion and instrumental analysis. The method includes two digestion procedures (microwave acid digestion and alkali fusion) in combination with inductively coupled plasma atomic emission spectrometry (ICP–AES). Total concentrations of the elements have been determined in suspended particulate matter from lake and river water with low levels of suspended solids (<2 mg l −1 DW), and a wide range of element concentrations. The precision of the method including filtration, digestion and instrumental determination ranges between 10 and 14% RSD for most elements on a dry weight basis. Non-detectable concentrations of some elements are reported due to small differences between blank filter levels and the amounts of elements present on the filters after sampling. The calculated sums of main inorganic components, expressed as oxides, ranges between 94.0 and 98.0% ash weight. The method limits of detection range between 3 and 100 μg, as estimated from the blank filter samples. These detection limits are 3–1000 times higher compared to the corresponding instrumental (ICP–AES) limits of detection. A better knowledge of the mechanisms of filter clogging in sampling of suspended matter is important in order to extend the applicability of the method. For the sample types investigated in this study, the amount of inorganic material in the suspended particulate matter (SPM) seems to be the most important factor controlling the maximum volume of filterable water, and Fe is presumably the most important clogging regulating parameter in the group of elements included in the inorganic matter. A critical evaluation of the indirect method of calculating concentrations in SPM as the difference between unfiltered-digested and filtered subsamples is also included.

Development of air quality indices for Mumbai, India

This paper proposes a simple approach for developing air quality indices for different sites in an urban region of India. The database used for calculating these indices included various physical and chemical characteristics of suspended particulate matter, such as particle size distribution, chemical (elemental) properties and parameters governing the acidity of precipitation. The indices were used to rank various sites in terms of air pollution, and higher indices indicated more polluted sites. The analysis showed that complex and large amounts of data could be converted into easily understandable simple numbers. The indices could thus serve as a ready reckoner for comparing different sites, and the information can be used to design efficient air quality management programmes and to frame appropriate abatement policies.

Aggregation and resuspension of suspended particulate matter at a seasonally stratified site in the southern North Sea: physical and biological controls

The physical and biological characteristics of suspended particulate matter (SPM) have been investigated at a site in the southern North Sea characterised by a seasonally stratified water column and a muddy sand bed. Significant variability in SPM concentration, composition, size and settling velocity was observed over tidal, spring/neap and seasonal time scales. Tidal currents alone are not sufficient to resuspend the bulk of the sea-bed sediment. However, sea-bed erosion does occur when wind/wave action enhances the bed shear stress during winter storms. Also, during winter and summer aggregated organic-rich material with a modal settling velocity of 0.2 mm s -1, originating from the sediment/water interface or from pelagic organic detritus, is subject to spring-tide or wind/wave resuspension. Phytoplankton production in the surface mixed layer (SML) is nutrient limited during much of the summer, but there can be sufficient light penetration to allow production at or below the thermocline. So production in the bottom mixed layer (BML) can be either light or nutrient limited, and BML nutrient levels do not gradually recover during the summer. Aggregation of phytoplankton is an important process at this site, resulting in significant modification of settling behaviour and hence dynamics of SPM. Settling velocity and particle size measurements indicate that both diatom and dinoflagellate blooms form large aggregates towards the end of their growth phase, with modal settling velocities between 2 and 5 mm s -1. Nitszchia pseudoseriata aggregates were relatively stable, remaining as viable sites for primary production over several cycles of tidal resuspension and deposition. Moreover, they efficiently ‘scavenged’ fine inorganic particles from the water column as they settled out. Tidal resuspension of these aggregates results in much higher water-column residence times than would be calculated simply from settling rate and water depth. This allows a greater proportion of remineralisation to be performed in the water column, rather than within the sea bed.

Biogeochemical characterization of suspended particulate matter in the Columbia River estuary

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 160:173-184 (1997) - doi:10.3354/meps160173 Biogeochemical characterization of suspended particulate matter in the Columbia River estuary F. G. Prahl*, L. F. Small, B. Eversmeyer College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA *E-mail: fprahl@oce.orst.edu In order to understand what controls the composition of suspended particulate material (SPM) in estuarine turbidity maxima (ETM), a set of SPM samples collected in the Columbia River and estuary (northwestern USA) during 3 seasons (fall 1990, summer 1991, spring 1992) was analyzed for detrital mineral (Min), total organic matter [OM, as 2 x particulate organic carbon (POC)], biogenic silica (BSi), chlorophyll a, δ13C, and lignin. In most samples, Min, OM and BSi collectively accounted for 100% of total SPM mass, although their relative importance changed seasonally. The ETM was a trap for organic matter during all 3 seasons, which can explain the intense microbial activity and microcrustacean grazing observed previously. The organic matter was particularly rich in chlorophyll a in late spring to early summer. The source of this seasonal enrichment was mainly riverine phytoplankton. The organic matter contribution to ETM from the ocean was minor compared to the river, but apparently not negligible. Despite large seasonal variations in chlorophyll content, the δ13C of POC concentrated in ETM remained nearly constant between -26 and -25.5o/oo. Vascular plant debris, as depicted by lignin phenol content, always comprised a minor fraction of the organic matter in ETM, although ETM had higher lignin levels than the OM of surrounding waters. Intertidal mudflats are if not an additional source of organic matter at least an important site for transforming riverine organic matter that is ultimately concentrated in ETM. Columbia River estuary · Estuarine turbidity maxima (ETM) · Mudflats · Suspended particulate material (SPM) · Particulate organic carbon (POC) · Chlorophyll · Lignin · Aluminum · Manganese Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 160. Publication date: December 15, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Quantification and characterisation of suspended particulate matter in indoor air

Quantification and characterisation of suspended particulate matter (SPM) from homes in the city of Oslo was carried out. In 29 households the dust concentrations were found to vary between 9 and 56 μg/m 3 (median value 26 μg/m 3). In 12 of the 29 households, a thorough analysis was carried out to determine the size and element distribution of the particles using transmission electron microscopy (TEM) and X-ray microanalysis (XRMA). The vast majority of the collected particles were less than 2.5 μm in diameter, i.e. they belonged to the fine fraction. In this fraction a considerable amount of soot and sulphur particles were found, usually less than 1 μm in diameter. The coarse fraction (particles > 2.5 μm in diameter) was found to consist mainly of organic material, silicates and larger soot aggregates. Both a thorough analysis of individual particles and a ‘bulk analysis’ (i.e. recording XRMA spectra from whole grid masks) were performed, and the two methods were found to show good agreement.

Geochemical considerations on trace element distributions in suspended matter and sediments at the river-sea interface, Adige River mouth, northern Adriatic sea

The particulate matter at the Adige River mouth has been investigated in order to determine the natural geochemical processes in the estuarine environment, and the anthropogenic influence on the biogeochemical cycling of heavy metals. The determination of suspended matter and sediment physico-chemical characteristics (grain size, mineralogy, organic matter content, specific surface area), and of concentrations of major and trace elements in the Adige River mouth in different hydrological conditions, has shown that this mouth acts as a trap for most heavy metals. Heavy metals were found to be preferentially bonded to the particulates, and in the estuarine mixing zone scavenging of most dissolved metals occurs, due to salinity and pH gradients, and to the formation of new particulate organic matter. The surface characteristics of suspended particulate matter [fine grain size, abundance of clay minerals, large specific surface area (SSA), organic and inorganic coatings] favour the adsorption of heavy metals. The sedimentation pattern (rapid deposition due to flocculation of fine particles, and to low environmental energy and estuarine circulation) causes accumulation of particulate matter, enriched in heavy metals, in the prodelta zone. Moderate anthropogenic influence on Cu, Pb, Cd, and Cr concentrations has been recognised in the Adige River. The environmental fate of these elements is determined by the same natural processes, and therefore accumulation in front of the river mouth occurs. The elevated partitioning in the organic phase of the anthropogenically influenced elements, could favour their mobility in different environmental conditions.