Water Suspended Matter Research Articles

The effect of suspended sediment depth distribution on coastal water spectral reflectance: theoretical simulation

Abstract The spectral distribution of water surface reflectance, in the visible region (0.4-0.7 µm), has been numerically estimated, for various concentration profiles of suspended matter in water, including contributions from yellow substances, chlorophyll and mineral sediment. Mie theory for light scattering, has been used to estimate extinction, scattering and absorption coefficients for a system of suspended spherical particles characterized by Junge size-distribution and containing absorbing and non-absorbing components. Significant changes in the shape of the simulated spectral reflectance have been obtained when the suspended sediment distribution in the water column, extending from the surface to the light penetration depth, varies. The preliminary theoretical results presented seem to sustain the possibility of retrieving sediment depth profile from remote sensed spectral data.

The high resolution imaging spectrometer (HIRIS) for Eos

The high resolution imaging spectrometer (HIRIS) designed for the Earth Observing System (Eos) is designed to acquire images in 192 spectral bands simultaneously in the 0.4-2.5- mu m wavelength region. HIRIS is a targeting rather than a continuous acquisition instrument and obtains high-spatial- and spectral-resolution images in a 30-km swath with a 30-m ground instantaneous field of view (GIFOV) in vertical viewing. Pointing will allow image acquisition at -30 degrees to +60 degrees along-track and +or-24 degrees cross-track. The raw data rate of the instrument is 512 Mbs. The high spectral resolution will make it possible to identify many surficial materials such as rocks, soils, and suspended matter in water directly. HIRIS also offers the possibility of studying biochemical processes in vegetation canopies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Evaluation of the ‘Fugacity' (FEQUM) and the ‘Exams' Chemical Fate and Transport Models: A Case Study on the Pollution of the Norrsundet Bay (Sweden)

Two different models have been used to investigate how chemicals present in wastewater from a kraft mill are transported and spread in an aquatic environment. The models, FEQUM (Fugacity EQUilibrium Model) and EXAMS, are presented, their characteristics explained and a comparison of the models is made. In FEQUM the concept of fugacity is considered as the driving force behind chemical transport. The EXAMS dispersion model uses water and sediment flow as the basis for calculating the dispersion of chemicals. FEQUM encompasses the whole environment, water, air, soil, sediments, suspended matter in water and biota, whereas EXAMS includes the aquatic domain only. Both models have been applied to the Norrsundet area. Norrsundet is a heavily polluted bay on the east coast of Sweden. The pollution is mainly due to a kraft mill located in the area. The models were calibrated using data on chloroform in wastewater and seawater, and then tested on four other pollutants present in the wastewater. Both models give satisfactory results for the compounds investigated, tetrachlorocatechol constituting the only exception. Correlation coefficients between calculated and measured concentrations vary from 0.86 to 0.97. The poor results obtained for tetrachlorocatechol are probably due to the especially high affinity of this compound for suspended particles.

Organic geochemistry of the deep ocean-sediment interface and interstitial water

The sea water-suspended matter—sediment—interstitial water interface was studied for samples collected in the eastern North Atlantic. Fatty acid and hydrocarbon analyses were performed by gas liquid chromatography and mass spectometry in conjunction with microbiological and biochemical studies (French Programme ORGON). The geochemistry of the ocean-sediment interface was examined for selected cores, either sterile or characterized by high heterotrophic bacterial concentrations and organic matter assimilation capacities. Enrichments in odd carbon numbered and polyunsaturated fatty acid concentrations connected to specific sediment levels analyzed by microbiologists demonstrate that the interstitial water is a specific medium in which to observe obvious traces of microbial activities in sediments.

Trace element fractionation by suspended matter in water

Fractionation of trace elements by silt and sediment particles in natural waters has been studied by means of radioactive tracers. Partition of dissolved tracer ions between sediments and water has been observed as well as the relative changes in concentration of fission product ions in a mixture, after contact with suspended particles in naturally occurring abundances. Gamma-ray spectra have been obtained to illustrate the extent of separation occurring as a result of preferential adsorption of some of the fission products on clay silt particles. In waters with a high organic content, the pattern of fractionation is different, as expected, with a higher extraction of anions and anionic complexes. The results have an important bearing on the degree of self-purification by bottom sediments in turbulent, polluted streams. Careful distinction is required in analytical reports between truly dissolved elements and total “dissolved solids,” which may include ions adsorbed on submicron silt particles.

A note on the action of common salt on the larvae of Stegomyia fasciata

It has been pointed out by Graham* that measures designed to bring about the destruction of mosquito larvae may be divided into (a) measures intended to destroy the larvae, and (b) measures intended to destroy their food supply. He points out that very little attention has been paid to the second method, which entails an exact knowledge of the freshwater algae. Graham found that the suspended matter in water in which the larvae of Pyretophorus costalis were breeding could be precipitated by the addition of 3 per cent, of common salt, and that then the larvae became cannibalistic and destroyed one another. He considered that this phenomenon was due to the larvae being deprived of their natural food, the algae, which had been destroyed by the addition of salt. “In lesser concentration,” he concluded, “salt appears to inhibit the growth of very young larvae, probably by diminishing the supply of food, but the development of fully-grown larvae appears to be hastened in a hypertonic medium, and they pass into and through the pupal stage with unusual rapidity.”

VI.—River Curves Round Alluvial Plains

In the Geological Magazine for October, 1902, Dr. Callaway mentions the explanation of these curves that I gave in a paper printed twenty-one years ago. His quotation should be read with the immediate context—”These [the tributary streams] keep open a channel into which the larger stream falls.” This is the essence of my argument.Professor Phillips and Sir A. Geikie have remarked that an alluvial plain in the course of a river may be regarded as an old lake-bottom, now drained; the lake-like appearance being renewed in times of flood. Let us suppose ABCB (Fig. 1) to represent such an area with a river flowing through it in a straight line, and, on one side, a tributary stream, or, to use a shorter and more expressive term, an affluent, coming in at an angle. Such a condition, if it existed, would not continue even in consolidated alluvial soil; it is still less likely to have existed in the soft mud when the area was first drained. A succession of floods would certainly wash away the bank where the affluent, coming through it, had caused a break in its continuity. By this the river-bed opposite the affluent would be expanded beyond its requirements when at low water. At every flood the whole of the bed of the river and the adjoining area of land will be covered with water, the ordinary river channel being effaced. From this water suspended matter falls and forms a deposit, visible after the flood has subsided, but in greater quantity on the banks by the sides of the low-water channel than on the adjoining land.