共查询到20条相似文献，搜索用时 109 毫秒
1.
Guy Boucher 《Marine pollution bulletin》1985,16(8):328-333
Long term temporal variations in nematode and copepod densities were monitored in the upper and lower part of the Bay of Morlaix (West Channel), which was heavily contaminated by the 1978 Amoco Cadiz oil spill. Deseasonalization of abundance data allowed estimates to be made of the different components, namely the annual and seasonal trends and the residue. Reduced nematode abundance was long lasting in both types of sediment investigated: it appeared to be a gradual decrease in sublittoral sand but there was a dramatic reduction in estuarine mud 2 years after disturbance. Copepod variability, however, was related to seasonal factors. 相似文献
2.
G.W. Gooday 《Marine pollution bulletin》1980,11(4):101-103
The intertidal symbiotic flatworm, Convoluta roscoffensis, was found on the sandy beach at Dunes de Ste. Marguerite 4 months after heavy pollution by oil from the Amoco Cadiz. Seven of the nine sites recorded 2 years previously had colonies of worms. The colonies were fewer and smaller, but densities within colonies were unchanged. 相似文献
3.
The ratio of nematodes to copepods was calculated for meiofauna samples from 17 beaches and additional values for intertidal and sublittoral sites were obtained from the literature. Intertidal ratios increased with decreasing particle size, but ratios from polluted sites were always extremely high. Sublittoral ratios increased with depth. It is suggested that this ratio has potential for monitoring organic pollution of sandy beaches. 相似文献
4.
Nematode response to metal, PAHs and organic enrichment in tourist marinas of the mediterranean sea 总被引：1，自引：0，他引：1
The structure of nematode assemblages was investigated in the sediments of two different tourist marinas in the Mediterranean Sea and related to pollution variables. Nematode densities and generic compositions were determined, as were concentrations of heavy metals, PAHs and organic matter. Results showed different assemblages at the two marinas, with a dominance of the genera Paralongicyatholaimus and Daptonema. Significant correlations between nematodes and concentrations of environmental contaminants were found. In particular, Paralongicyatholaimus showed a significant negative correlation with Cu concentrations and was almost absent at the stations where higher Cu concentrations were found. The presence of sensitive/tolerant nematode genera represents a promising tool to identify areas subjected to a higher level of disturbance and to define the correct environmental management strategy for harbors. 相似文献
5.
P.J.D. Lambshead 《Marine pollution bulletin》1984,15(7):256-259
An analysis is presented of some intertidal meiofauna assemblages from the Firth of Clyde. The results cast doubt on the validity of the nematode/copepod ratio as a means of assessing marine pollution. In the light of this analysis, data from the literature on the meiofauna assemblages of the Firth of Clyde are reinterpreted. It is concluded that the ratio is unreliable because (a) it oversimplifies a highly complex set of relationships and (b) nematode and copepod populations may react independently to a variety of environmental parameters, of which pollution is only one. In these circumstances it is suggested that the ratio should be abandoned as a practical pollution indicator. 相似文献
6.
The nematode/copepod ratio and its use in pollution ecology 总被引：1，自引：0，他引：1
R.M. Warwick 《Marine pollution bulletin》1981,12(10):329-333
The nematode/copepod ratio is critically examined with a view to adding some precision to its proposed use in pollution ecology. At two unpolluted intertidal sites, differing markedly in sediment grade, the metabolic requirements of copepods are shown to be equivalent to the requirements of that fraction of the nematode population which feeds in the same way. The partitioning of this total energy requirement among individuals depends on the distribution of individual metabolic body sizes and the relative rates of metabolism. The distribution of body sizes is constrained by the sediment granulometry, which affects nematodes and copepods differently. These considerations enable precise predictions of the nematode/copepod ratios expected in unpolluted situations, against which observed ratios can be compared. 相似文献
7.
P.A. Read K.J. Anderson J.E. Matthews P.G. Watson M.C. Halliday G.M. Shiells 《Marine pollution bulletin》1983,14(1):12-16
A long-term benthic study has been undertaken in the Firth of Forth to assess the environmental impact of a new sewage treatment scheme for the city of Edinburgh. The Sewage Scheme reduces the suspended solids content of the liquid effluent by approximately 60% and achieves a lowering of the concentration of materials in solution through more efficient dilution and dispersion. Marked changes in the intertidal benthic flora and fauna have been recorded along the Edinburgh coastal zone. These changes have been apparent as the decline and disappearance of populations of certain pollution indicator species and the appearance and establishment of several species previously unrecorded along the more polluted parts of the Edinburgh shoreline. Study of the sublittoral benthos has shown no deleterious effect arising from the new effluent outfall, although there does appear to be some enhancement of the fauna in the area. 相似文献
8.
The spatiotemporal distributions of dissolved and/or dispersed oil in seawater and pore water were monitored on site by fluorometric detection method after the Hebei Spirit oil spill. The oil concentrations in intertidal seawater, 15 days after the spill, were as high as 16,600 μg/L and appeared to decrease below the Korean marine water quality standard of 10 μg/L at most sites 10 months after the spill. Fluorometric detection of oil in pore water was introduced to eliminate the effects of grain size for the quantification of oil in sediments and to better explain spatial and temporal distribution of oil pollution at sandy beaches. The fluorescence detection method was compared with the conventional laboratory technique of total petroleum hydrocarbon analysis using gas chromatography. The method of fluorescence detection of oil was capable of generating results much faster and more cost-effectively than the traditional GC technique. 相似文献
9.
The most important natural function of exposed sandy beaches is the filtration of large volumes of sea water which are flushed through the interstitial pore system by the actions of tides and waves. In this process organic material is mineralized by the interstitial fauna and nutrients returned to the sea. This paper examines the physical effects of oil in blocking or reducing this filtration. Reduced filtration of sea water may be caused by prevention or retardation of interstitial water flow and/or decrease in pore space. The magnitude of the effects depends on the volume of oil, its state of weathering, its location on the beach and its degree of admixture with sand. It appears that under all but the heaviest conditions of pollution these effects are relatively small and only become significant in situ when discrete layers of weathered oil occur near the surface in the upper intertidal zone where maximum water input normally occurs. 相似文献
10.
P. W. French 《Marine pollution bulletin》1993,26(12):692-697
A series of 150 samples from the contemporary intertidal zone of the Severn Estuary and Bristol Channel have been analysed for levels of copper, lead, zinc, rubidium, and particulate coal debris to investigate the present pollution status of the system. The analysis reveals a systematic streamwise variation in pollution concentrations which is taken to reflect a combination of land-based pollutant inputs and the reworking of pollutant-rich sediments from the erosion of salt marshes along the margins of the estuary.
This streamwise variation demonstrates a down-stream decrease in concentration, superimposed on which are nine areas of contemporary pollutant input with regard to metals but non relating to coal. The occurrence of coal in modern intertidal sediments at levels significantly higher than the underlying pollution trend is only possible via the reworking of anthropogenically derived material stored in the intertidal sediments of the system and from a wreck located offshore. 相似文献
11.
The intertidal bivalve mollusc Macoma balthica shows potential as an indicator of oil pollution. In experiments designed to simulate stranding of an oil slick on a mudflat, a significant increase in mortality of this species was found to accompany increasing concentration of petroleum in sediment and increasing duration of exposure. 相似文献
12.
Impact of discards of beam trawl fishing on the nematode community from the Tagus estuary (Portugal)
Franco MA Steyaert M Cabral HN Tenreiro R Chambel L Vincx M Costa MJ Vanaverbeke J 《Marine pollution bulletin》2008,56(10):1728-1736
The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments. 相似文献
13.
We discuss the use of the nematode to copepod ratio in relation to determining the extent of metals impact using the Cha?aral area of northern Chile, where the dumping of copper mine tailings has taken place for many years, as an example. Data were collected from 12 beaches in the area on eight occasions between January 1997 and October 1998. We find that the ratio is not a good predictor of pollution due to the generally low densities of meiofauna on impacted beaches and the absence of harpacticoid copepods from those beaches. We suggest that in the case of metal pollution the mean number of Harpacticoida per site may be a better indicator of impact stress. We rule out the use of the nematode to copepod ratio as an indicator in biomonitoring studies where metal enrichment is thought to occur. 相似文献
14.
Frans Witte Ole Seehausen Jan H. Wanink Mary A. Kishe-Machumu Marjolein Rensing Tijs Goldschmidt 《Aquatic Sciences - Research Across Boundaries》2013,75(2):169-183
During the past decades, major anthropogenic environmental changes occurred in Lake Victoria, including increased predation pressure due to Nile perch introduction, and decreases in water transparency and dissolved oxygen concentrations due to eutrophication. This resulted in a collapse of the haplochromine cichlids in the sub-littoral waters of the Mwanza Gulf in 1986–1990, followed by a recovery of some species in the 1990s and 2000s, when Nile perch densities declined. We studied two data sets: (1) haplochromines from sand and mud bottoms in the pre-collapse period; (2) haplochromines from sub-littoral areas during the pre-collapse, collapse and recovery periods. Water over mud is murkier and poorer in oxygen than water over sand, and differences in haplochromine communities in these natural habitats during the pre-collapse period may predict the effects of anthropogenic eutrophication during the collapse and recovery periods. In the pre-collapse period, haplochromine densities over sand and mud did not differ, but species richness over sand was 1.6 times higher than over mud bottoms. Orange- and white-blotched colour morphs were most common at the shallowest sand station. More specifically, insectivores and mollusc-shellers had higher numbers of species over sand than over mud, whereas for mollusc-crushers no difference was found. Laboratory experiments revealed that mollusc shelling was more affected by decreased light intensities than mollusc crushing. During the pre-collapse period, spawning occurred year-round in shallow areas with hard substrates and relatively clear water. In deeper areas with mud bottoms, spawning mainly occurred during months in which water clarity was high. No effects of hypoxia on spawning periods were found. It follows that clearer water seems to support differentiation in feeding techniques as well as year-round spawning, and both may facilitate species coexistence. Water clarity is also known to be important for mate choice. These observations may explain why, since the decline of Nile perch, haplochromine densities have recovered, the numbers of hybrids increased and species diversity in the current eutrophic sub-littoral waters has remained 70 % lower than before the environmental changes. 相似文献
15.
van der Wal D Forster RM Rossi F Hummel H Ysebaert T Roose F Herman PM 《Marine pollution bulletin》2011,62(1):99-108
An experiment was performed to test an alternative dredging strategy for the Westerschelde estuary. Clean sand dredged from the navigation channel was disposed seawards of an eroding intertidal flat in order to modify morphology and hydrodynamics, improving the multi-channel system with ecologically productive shallow water habitat. Five years of intensive monitoring revealed that part of the disposed sediment moved slowly towards the flat, increasing the very shallow subtidal and intertidal area, as planned. The sand in the impact zone became gradually finer after disposal, possibly due to reduced current velocities. Nevertheless, no changes in macrobenthic biomass, density, species richness and composition were detected in the subtidal zone, also demonstrating rapid macrobenthic recovery. In the intertidal zone, no ecological effects could be revealed superimposed on trends associated with long-term sediment fining. Thus, despite morphological success and absence of detected negative ecological impacts of the experiment, new beneficial habitat was not created. 相似文献
16.
The major process involved in the removal of stranded petroleum residues or ‘tar lumps’ from sandy high energy beaches is the adsorption of sand and shell particles to the residues effecting a density change. This results in transport off the beach, sinking, and sometimes burial of the tar in sublittoral sediments. 相似文献
17.
The effects of plastic fines on the instability of sand were studied in this article. For this purpose, the results of undrained monotonic triaxial compression tests conducted on specimens of sand with variation in fines content from 0% to 30% are presented. The specimens were prepared in two different initial dry unit densities and were subjected to two different confining pressures. The results of the tests are shown in four groups. They demonstrate that an increase in plastic fines leads to an increase in the instability, followed by a decrease with a further increase in fines content. It is also seen that the slope of the steady-state lines in p’-q space increases with increase in fines content, but after certain fines content, it begins to decrease. A reverse trend is observed for the slope of instability lines; it decreases at lower fines content, followed by an increase with a further increase in fines content. 相似文献
18.
The physicochemistry of the Black River and adjacent marine beach, in terms of tidal, daily and seasonal fluctuations of temperature and salinity, presents a highly stressed environment exacerbated by canalization of the river mouth. Riverine pollution further stresses this environment, producing low densities and diversities of marine infauna adjacent to the river. No fauna were found in the river mouth where typical estuarine conditions exist only during high tide. Tolerance of the dominant marine species, Cerebratulus fuscus, to temperature, salinity and river water combinations showed that mortality was more rapid after exposure to river water dilutions than after exposure to distilled water dilutions. Computer-generated models suggested that this species should survive conditions closer to the river than were observed. This confirmed additional stress due to pollution carried in the river from urban and industrial drainage. Lower river water temperatures during winter appear to ameliorate pollution stress, enhancing survivability of the infauna. 相似文献
19.
The sediment parameters and nematode assemblages in the intertidal zone of the Hichirippu shallow lagoon, Hokkaido, Japan, were investigated. The objectives of this study were to observe the seasonal variation in the nematodes in the sediment, and to investigate the relationships between the nematodes and environmental factors. Samples were collected bi-monthly from five stations on the tidal flat from April 2003 to February 2004. It was found that the sediment parameters (Chl a concentration, AVS, TOC and TN contents) varied throughout the 10-month study. Fifty-four species of nematodes were found in the study area. The density and biomass of the nematodes varied in accordance with the sediment temperature during the sampling period. In this study, there was a seasonal variation in the nematode assemblage found in the intertidal zone of this shallow lagoon. The important factors affecting this variation were sediment temperature, and food competition among the nematodes themselves. The seasonal variation of the nematode also showed a relationship with the Chl a concentration in the sediment during the sampling period. 相似文献
20.
In 1981–83 sublittoral macroinvertebrates were collected by means of SCUBA diving from artificial substrates submerged near
the outfalls from eight sewage treatment plants in Lake Zürich. Pollution around the outfall resulted on the one hand in a
reduction of pollution intolerant benthic invertebrates, on the other hand in a considerable increase in the relative abundance
of pollution tolerant taxa such as leeches, flatworms and crustaceans. Changes in the faunal composition were related to nutrient
enrichment and changes in the nature of the substratum due to sedimentation of sewage sludge. Species diversity (Simpson index)
showed low values near the outfall from some plants, high values near the outfall from others. Low species diversity did not
always mark the sites where greatest pollution has been observed.
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