Marine soft-bottom benthic community offshore from Black Rock sewage outfall, Connewarre, Victoria

1980 ◽  
Vol 31 (2) ◽  
pp. 155 ◽  
Author(s):  
JH Dorsey ◽  
RN Synnot
Keyword(s):  
Shallow Water ◽  
Benthic Community ◽  
Sewage Effluent ◽  
Soft Bottom ◽  
Suspension Feeders ◽  
Sewage Outfall ◽  
Fine Grained ◽  
Sandy Sediments

The shallow-water benthic community offshore from Black Rock sewage outfall consists of a moderately diverse crustacean and polychaete infaunal assemblage living in fine-grained, homogeneous, sandy sediments. Most organisms are detritus- or suspension-feeders, with detritus coming largely from planktonic and suspended sources. Sewage effluent may secondarily enrich inshore sediments which support dense populations of spionid polychaetes and Callianassa ceramica.

Changes in the benthic community of china clay waste deposits in Mevagissey Bay following a reduction of discharges

1981 ◽  
Vol 61 (3) ◽  
pp. 789-804 ◽  
Author(s):  
P. Keith Probert
Keyword(s):  
Benthic Community ◽  
Species Interactions ◽  
Suspended Solid ◽  
Soft Bottom ◽  
Fine Grained ◽  
China Clay ◽  
Suspended Solid Concentration ◽  
Amphiura Filiformis ◽  
Faunal Density ◽  
Deposit Feeding

Macrobenthic infauna was sampled in Mevagissey Bay, off the south coast of Cornwall, England, when the bay was receiving fine-grained mineral waste from the china clay industry at a rate of about 450000 tons per annum. Quintuplicate 0·1 m2 grab samples, washed on a 0·5 mm mesh, were taken on 15 occasions over two years at a station about 1 km from the outfall and at a water depth of 13 m. The fauna had a range of density of 755–2144 individuals/0–5 m2 and in composition resembled a partially impoverished Echinocardium cordatum/Amphiurafiliformis community. Population densities of Goniada maculata (Polychaeta), Cingula semicostata (Gastropoda), Nucula turgida, Mysella bidentata, Venus striatula and Tellina fabula (Bivalvia) showed no clear trends during the two years' sampling. Magelona filiformis (Polychaeta), Abra alba and Phaxas pellucidus (Bivalvia), Acrocnida brachiata and Amphiura filiformis (Ophiuroidea) declined in abundance, whereas the densities of Nephtys hombergi (Polychaeta) and Labidoplax digitata (Holothurioidea) increased. L. digitata became the commonest species, with a peak density of 708 individuals/0·5 m2. A month after sampling began the rate of waste discharged was reduced from 700000 tons per annum, but this did not appear to improve conditions for the benthic community. Total faunal density remained relatively stable but species diversity declined. It is argued that the suspended solid concentration was unlikely to have adversely affected the predominantly deposit-feeding community, but that persistent sediment instability continued to be a source of stress. Nevertheless, the observed major changes of community structure were similar to natural fluctuations of coastal soft-bottom populations resulting from species interactions and differences of larval success.

The shallow-water soft-bottom benthos in lindåspollene, western Norway

Sarsia ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Jens Petier Taase ◽  
Tore Høisæter
Keyword(s):  
Shallow Water ◽  
Soft Bottom ◽  
Western Norway

scholarly journals Crevasse splays within a lignite seam at the Tomisławice opencast mine near Konin, central Poland: architecture, sedimentology and depositional model

Geologos ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Lilianna Chomiak
Keyword(s):  
Middle Miocene ◽  
Structural Features ◽  
Fine Grained ◽  
Opencast Mine ◽  
Main River ◽  
Main River Channel ◽  
Lignite Mine ◽  
Flooding Event ◽  
Crevasse Splay ◽  
Sandy Sediments

AbstractThe present article focuses predominantly on sandy deposits that occur within the Middle Miocene lignite seam at the Tomisławice opencast mine, owned by the Konin Lignite Mine. As a result of mining activity, these siliciclastics were available for direct observation in 2015–2016. They are situated between two lignite benches over a distance of ~500 m in the lower part and ~200 m in the higher part of the exploitation levels. The maximum thickness of these sandy sediments, of a lenticular structure in a S–N cross section, is up to 1.8 m. With the exception of a thin lignite intercalation, these siliciclastics comprise mainly by fine-grained and well-sorted sands, and only their basal and top layers are enriched with silt particles and organic matter. Based on a detailed analysis of the sediments studied (i.e., their architecture and textural-structural features), I present a discussion of their genesis and then propose a model of their formation. These siliciclastics most likely formed during at least two flood events in the overbank area of a Middle Miocene meandering or anastomosing river. Following breaching of the natural river levee, the sandy particles (derived mainly from the main river channel and levees) were deposited on the mire (backswamp) surface in the form of crevasse splays. After each flooding event, vegetation developed on the top of these siliciclastics; hence, two crevasse-splay bodies (here referred to as the older and younger) came into existence. As a result, the first Mid-Polish lignite seam at the Tomisławice opencast mine is currently divided in two by relatively thick siliciclastics, which prevents a significant portion of this seam from being used for industrial purposes.

TWO MODELING APPROACHES FOR REVERBERATION IN A SHALLOW WATER WAVEGUIDE WHERE THE SCATTERING ARISES FROM A SUB-BOTTOM INTERFACE

2009 ◽  
Vol 17 (01) ◽  
pp. 29-43 ◽  
Author(s):  
CHARLES W. HOLLAND ◽  
DALE D. ELLIS
Keyword(s):  
Shallow Water ◽  
Silty Clay ◽  
Sediment Layer ◽  
Angle Distribution ◽  
Vertical Angle ◽  
Fine Grained ◽  
Bottom Interface ◽  
Grazing Angles ◽  
Scattering Kernel ◽  
Sediment Interface

In shallow water environments where the uppermost sediment layer is a fine-grained fabric (e.g. clay or silty-clay), the observed reverberation may be dominated by scattering from the sub-bottom. Here, reverberation predictions from normal mode and energy flux models are compared for the case where the scattering arises from a sub-bottom half-space under a fine-grained sediment layer. It is shown that in such an environment, the position of the angle of intromission, in addition to the angular dependence of the scattering kernel, is a factor controlling the reverberation and its vertical angle distribution. It is also shown that the reverberation from a sub-bottom horizon is typically governed by higher grazing angles than the case where the scattering occurs at the water–sediment interface. There was generally very close agreement between the models as a function of frequency (200–1600 Hz), layer thickness (0–8 m), and range (1–15 km). The model comparisons, showing some differences, illuminate the result of different approximations in the two approaches.

Intra-annual Variability in Hawaiian Shallow-water, Soft-bottom Macrobenthic Communities Adjacent to a Eutrophic Estuary

2000 ◽  
Vol 50 (2) ◽  
pp. 245-258 ◽  
Author(s):  
S.A. Mccarthy ◽  
E.A. Laws ◽  
W.A. Estabrooks ◽  
J.H. Bailey-Brock ◽  
E.A. Kay
Keyword(s):  
Shallow Water ◽  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Annual Variability

A modern soft-bottom, shallow-water crinoid fauna (Echinodermata) from the Great Barrier Reef, Australia

Coral Reefs ◽  
2005 ◽  
Vol 25 (1) ◽  
pp. 164-168 ◽  
Author(s):  
C. G. Messing ◽  
D. L. Meyer ◽  
U. E. Siebeck ◽  
L. S. Jermiin ◽  
D. I. Vaney ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Shallow Water ◽  
Barrier Reef ◽  
Soft Bottom

Surficial Sediments of Lake Erie

1976 ◽  
Vol 33 (3) ◽  
pp. 385-403 ◽  
Author(s):  
R. L. Thomas ◽  
J.-M. Jaquet ◽  
A. L. W. Kemp ◽  
C. F. M. Lewis
Keyword(s):  
Grain Size ◽  
Shallow Water ◽  
Lake Erie ◽  
Central Basin ◽  
Sediment Accretion ◽  
Western Basin ◽  
Grab Sampling ◽  
Fine Grained ◽  
Basin Region ◽  
Skewness And Kurtosis

On the basis of extensive echosounding and grab sampling, three major units have been recognized in Lake Erie: till and bedrock, glaciolacustrine clay, and postglacial muds. These units represent the late glacial and postglacial evolution of the basin and occur in an offshore younging sequence. The main basin of the lake is subdivided by residual glacial moraines into four depositional basins: Western, Sandusky, Central, and Eastern basins. The sediment texture has been defined by moment measures (mean, standard deviation, skewness, and kurtosis), the trends of which are related to the mixing of two primary grain-size populations in the sand- and clay-size ranges. A third grain-size mode in the silt size, composed of fine quartz with some carbonate, has been recognized. This mode has a modifying effect on the symmetry of the two primary populations and may, to some extent, be sufficiently abundant to behave as a discrete population. The trends in the textural characteristics, particularly skewness and kurtosis, have been utilized to define energy regimes at the sediment–water interface which indicates three distinct sedimentary or hydraulic regions: 1) Western basin region — Fine-grained sediment accretion in shallow water related to an imbalance in sediment budget, with high input loadings of fine-grained sediment, and deficit in coarse materials, with an excess of input over sediment export to the Central basin region. This results in net sediment accretion in shallow water with texture in disequilibrium with environmental energy, which produces mixing and suspension, followed by redeposition; 2) Central basin region — West to East coarsening of sediment in textural equilibrium with hydraulic energy, as it relates to increasing fetch under westerly and southwesterly prevailing winds; 3) Eastern basin region — Deepwater basin with sediments showing decreasing size offshore with increasing water depth. The deepwater sediment is modified by the influx of substantial quantities of the silt-size material derived from shoreline erosion in the north shore of the Central basin region.The interrelationships of parameters indicate textural dependence on mineralogic composition, particularly important being the relationship of clay concentration to mean grain size. This has particular value in modelling the physical behavior of clay-associated geochemical elements such as phosphorus.

Effect of sewage effluent on dragonflies (Odonata) of Bulimba Creek, Brisbane

1982 ◽  
Vol 33 (3) ◽  
pp. 517 ◽  
Author(s):  
JAL Watson ◽  
AH Arthington ◽  
DL Conrick
Keyword(s):  
Water Quality ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Contaminated Site ◽  
Sewage Effluent ◽  
Sewage Outfall

The adult dragonfly fauna and the larval fauna and abundance decrease markedly immediately downstream of the outfall from the Mimosa Sewage Treatment Plant into Bulimba Creek. The adult fauna is substantially restored farther downstream, but the larval fauna and abundance are not. Of the 36 species of Odonata observed at Bulimba Creek, the 10 abundant, essentially stream-dwelling species were most affected by the sewage effluent. Adults of only one of these stream species were found at the most contaminated site, and then only in very low numbers; those of two others were not observed downstream of the outfall. The diversities of both adult and larval dragonfly faunas give a qualitative indication of water quality. Parallels between the distribution or abundance of Odonata and the concentrations of contaminants indicate that chlorine may be the most important toxicant immediately downstream of the sewage outfall in Bulimba Creek.

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