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1.
The effects of zinc being added to sea water, to final concentrations of 0·1–20 ppm, have been studied on the heart rate, valve movements, mortality of Scrobicularia and on both isolated and in situ inhalant siphon preparations.The acute toxicity threshold for added zinc was determined to be about 10 ppm at 10°C. The median lethal times for 10 and 20 ppm zinc were 143·5 and 116·1 h respectively.The responses of Scrobicularia to zinc concentrations in sea water of between 0·1 and 10 ppm were tested by exposure for 6 h. Above 1 ppm, valve closure and bradycardia occur within 10–15 min. Below 5 ppm the valves subsequently opened and heart rate increased over the 6 h period, but in 10 ppm closure and pronounced bradycardia were maintained throughout.Addition of zinc, to final concentrations of 1, 5 and 10 ppm, had no effect on the isolated inhalant siphon in contrast to copper at 0·25 and 0·5 ppm which caused very marked siphonal contractions. However, when zinc (1–10 ppm) was added to an in situ inhalant siphon preparation, contractions occurred which were lost on removal of zinc from the bathing medium. Cutting the cruciform muscles medially resulted in the loss or delay of the response to zinc. This suggests the possibility of the cruciform muscle complex (muscle strands and associated sense organs) responding to zinc. This contrasts with the direct action of copper on the neuromuscular system of an isolated siphon.  相似文献   

2.
Concentrations of zinc, manganese, copper, cadmium, magnesium and iron in three species of red, four species of brown and three species of green macroalgae, and also in sea water have been determined at two localities along the coast of Aqaba. Significant differences in metal concentrations were found between the various species (P<0·01). Similar significant differences were found with regard to different metals (P<0·001). Concentration factors ranged between 102 for Cd and 9·2 × 104 for Fe. The difference in levels of metals between the two localities, however, was not significant (P > 0·05). Of the three groups of algae examined, rhodopytes exhibited the highest concentration power of metals.  相似文献   

3.
The effects of ozone-produced oxidants (OPO) on three developmental stages of the American oyster, Crassostrea virginica, were evaluated. Both straight-hinge (48-h post fertilisation) and setting pediveliger larvae were exposed to a series of OPO concentrations ranging from 0·05 to 0·30 mg/litre OPO (as total residual chlorine) at 25°C for 96 h. Mortality was used as the response parameter and results were quantitatively compared with the effects of chlorine-produced oxidants (CPO) obtained from the literature on these same developmental stages. Adult oysters (2- to 4-year class) were exposed to OPO concentrations ranging from 0·01 to 0·50 mg/litre at 15°C for 5 days and to the same concentration range at 25°C for two consecutive 6-day periods. Shell deposition and faecal matter accumulation were used as the response parameters for this stage.Straight-hinge larvae were significantly more sensitive to OPO than setting pediveliger larvae. Both larval stages were significantly more sensitive to CPO than to OPO. Shell deposition was significantly inhibited at all OPO concentrations for both 15°C and 25°C acclimated adult oysters. No significant differences were found between the shell deposition response of oysters at the two acclimation temperatures. Faecal matter accumulation was significantly reduced at OPO concentrations ≥ 0·05 mg/litre at both 15°C and 25°C. It was significantly (p < 0·05) greater for 25°C acclimated oysters than for 15°C acclimated oysters at OPO concentrations < 0·10 mg/litre but not at higher concentrations.  相似文献   

4.
Pacific oyster, Crassostrea gigas Thunberg, embryos were exposed to copper and silver salts, alone and in combination, through the completion of embryogenesis and metal effects upon normal embryonic development were monitored. Copper concentrations throughout the test period ranged from 0·0 to 12·0 μg litre?1 while silver concentrations were between 0·0 and 18·0 μg litre?1.Administered individually, silver and copper yielded decreasing per cent normal embryonic development with increasing metal concentration. However, both metals exhibited ‘plateaus’ wherein per cent normal embryonic development did not decrease with increasing metal concentration until a particular concentration was attained. A rapid decrease in per cent normal embryonic development occurred with increasing metal concentrations greater than 6·0 μg litre?1 copper and 11·0 μg litre?1 silver.The dose-response patterns of copper and silver appear to be similar with copper exhibiting somewhat greater toxicity. At a copper concentration of 10 μg litre?1 only 50% of the embryos could be considered normally developed, whereas silver concentrations between 16·0 and 18·0 μg litre?1 yielded 50% normal embryonic development.Response surface methodology indicated that copper and silver interacted additively, with embryonic development affected to a much greater degree by copper than by silver. Optimum development of Crassostrea gigas embryos was greatly influenced by copper concentrations and occurred at all silver concentrations wherein the corresponding copper concentrations were 6·0 μg litre?1 or less. Above 6·0 μg litre?1 copper, per cent normal embryonic development was significantly reduced, even at the lowest tested silver concentrations.Abnormal embryos exhibited retarded shell growth, reduced size and extremely erratic swimming behaviour. These sublethal effects probably have a biochemical origin and would limit the organism's capacity to feed properly, escape predation and develop normally, thereby reducing the chances of successful metamorphosis and recruitment into the adult population.  相似文献   

5.
Excreted salts and leaves from the Salt Marsh Cordgrass Spartina alterniflora were collected from two different sites. One site, Piles Creek (PC), is near heavily industrialized Linden, New Jersey, USA. The other site, Big Sheepshead Creek (BSC), is located near non-industrialized Tuckerton, New Jersey, USA. PC soil concentrations of mercury were 18·17 ± 7·67 ppm, while BSC soil concentrations were 0·22 ± 0·04 ppm. Spartina leaves from PC contained 0·16 ± 0·07 ppm of mercury, and BSC leaves contained 0·02 ± 0·0 ppm. Laboratory studies showed that S. alterniflora from both sites was capable of excreting mercury. Field collected salts from PC Spartina plants contained 0·11 ± 0·02 ppm of mercury, 2·60 ± 0·52 ppm of cadmium and 11·98 ± 0·94 ppm of zinc. These levels of heavy metals were as much as five- and-a-half times the concentrations of these metals found in ambient sea salts.  相似文献   

6.
Mussels, Mytilus edulis L., were exposed to elevated concentrations of copper or cadmium in the laboratory, then placed in cages in the sea (salinity 7‰). One year later maximum lengths of the mussels were measured and shells screened for deformities. Growth was 0·6 cm year?1 in the control cages and retarded in cages of exposed mussels. A total of 63% of cadmium-exposed and 46% of copper-exposed mussels had shell deformities. In the control cages 26% were deformed while in a natural population only 3% were deformed. The proportion of deformities to growth was inversely related. Low concentrations showed their injuriousness in this long-term test, probably due to the closing of the valves during exposure to high concentrations.  相似文献   

7.
The addition of stock copper and zinc nitrate solutions to filtered seawater (pH 7·91) resulted in a large pH shift which was more pronounced with copper. The pH shift was minimized by increasing the buffering capacity of seawater using 10 mm Tris-Tes pH 7·91. Subsequent experimentation was carried out in both unbuffered and buffered seawater.In unbuffered seawater, both copper and zinc had a pronounced inhibitory effect on Mytilus edulis sperm respiration with 50% inhibition occurring at 0.65 mm (41·3 ppm) copper and 1.0 mm (65·4 ppm) zinc. Egg respiration was also inhibited by copper with 50% inhibition occurring at 0.9 mm (57·2 ppm) whereas zinc inhibited egg respiration by only 30% at 1·5 mM (98·1 ppm).In buffered seawater, both copper and zinc produced an inhibitory effect on sperm respiration. However, with copper the inhibition was much reduced whereas zinc had tthe same inhibitory effect as in unbuffered seawater. In contrast to unbuffered seawater, egg respiration was stimulated by copper but zinc produced a comparable respiratory inhibition. The uptake of both copper and zinc in sperm and egg in buffered seawater increased with increasing metal concentration. Metal ion uptake, when expressed as ng ions μl cell volume?1, was approximately 3-fold greater in the sperm than in the eggs and in both cases zinc uptake exceeded copper uptake.At a seawater pH of < 7·5, in the absence of copper or zinc, the respiration of both egg and sperm was inhibited. The maximum levels of inhibition at pH 5·4 were 15% and 30% for sperm and egg, respectively.The differing actions of copper on egg respiration in buffered and unbuffered seawater appear to be due to enhanced copper uptake in unbuffered seawater.  相似文献   

8.
Lower molecular weight volatile fatty acids are important intermediates in the anaerobic degradation of organic matter in marine sediments. The analysis of these compounds at the low in situ concentrations, however, still presents difficulties. A new derivatization procedure for the analysis of these compounds, coupled with high-performance liquid chromatography, has been modified for the analysis of volatile fatty acids in marine pore water to cover a linear calibration range from 0·5 μm to 10 mm. The modifications resulted in the detection of concentrations 40 times lower than in the original method and in good recoveries of fatty acid standards added to pore water (mean 101%). This modified procedure was then used to analyse fatty acids in pore water from sediments along a gradient of organic enrichment. The relative ratios of the individual acids were 1:0·1:0·02:0·01:0·02:0·01 for acetate, propionate, n-butyrate 2-methylbutyrate, iso-valerate and n-valerate. There was a tendency for the concentration of the more reduced acids to increase (propionate and n-butyrate) as organic enrichment increased. Several fatty acids were found that have not commonly been reported in marine pore water. These include 2-methylbutyrate, which is a specific anaerobic degradation product of iso-leucine, which, to the authors' knowledge, has not been previously found in marine pore water.  相似文献   

9.
Sensitivity of larval Paralithodes camtschatica and Eualus suckleyi exposed 20 min–96 h to the water-soluble fraction (WSF) of crude oil was determined. Swimming cessation in half the animals occurred within 20 minutes' exposure to 2 ppm WSF for shrimp larvae and only 0·5 ppm for crab larvae. Half the larvae of both species died after 6 hours' exposure to 8 ppm or 24 hours' exposure to 2–4 ppm, but deaths did not occur until several days after exposure ended. In the field, most non-swimming larvae would probably die as well.  相似文献   

10.
Three species of estuarine invertebrates, Palaemonetes pugio (grass shrimp), Pagurus longicarpus (hermit crab) and Argopecten irradians (bay scallop), were exposed to Cd in flowing seawater at concentrations of 0·06, 0·12, 0·25, 0·5 and 1·0 mg/litre. Incipient LC50 values of 0·53 and 0·07 mg/litre were estimated for bay scallop and hermit crab, respectively. The toxicity curve for grass shrimp had not stabilised, but the incipient LC50 value was estimated to fall within a range of 0·2 to 0·3 mg/litre. Short-term response, as measured by time to 50% mortality at the highest Cd concentration, was 10, 21 and 23 days for the bay scallop, hermit crab and grass shrimp, respectively. Scallop growth was inhibited at all exposure concentrations with a measured 42-day EC50 value of 0·078 mg/litre Cd. Byssal thread detachment precedes death in bay scallops. An EC50 value of 0·54 mg/litre Cd for byssal detachment was measured on day 8 of the bioassay before appreciable mortality. This compared favourably with the incipient LC50 value of 0·53 mg/litre Cd. Cadmium accumulation occurred at all concentrations in bay scallop and grass shrimp.  相似文献   

11.
Chlorine, used to control bio fouling in coastal power station, sea water cooling circuits, is also toxic to non fouling marine organisms. Experiments quantified the toxicity of power station cooling water to postlarval Atlantic herring Clupea harengus L. Postlarvae were exposed to chlorinated sea water for 30 min, to simulate passage through a typical power station cooling water circuit, and 24h, during which detectable chlorine decayed away, to simulate a ‘worst case’ exposure. Twenty four hour LC50S were 0·63 ppm initial concentration for 30 min exposure and 0·36 ppm initial concentration for 24 h exposure. The present findings are contrasted with work assessing the suitability of power station cooling water for aquaculture which used maintained concentrations of chlorine.  相似文献   

12.
A seasonal study of trace metal behavior and transport in the Brazos River estuary was conducted in the winter, spring and fall of 1981. Surface water was analyzed for total dissolved Pb, Cu, Mn and Fe, and particulate Cd, Pb, Cu, Mn and Fe. Ancillary data included river discharge, total suspended matter, pH, major ions, nutrients, dissolved and particulate organic carbon and humic acid.The major ions were generally conservative across the river water-seawater mixing zone; however, a significant input of alkalinity and Ca was measured in the spring, attributable to cation exchange on clays and sediment diagenetic processes. Distinct concentration maxima were found in the 3–10‰ chlorinity range for dissolved Pb (0·06–0·9 nm), Cu (6–42 nm), Mn (2–290 nm) and Fe (5–80 nm). Particulate metal concentrations showed significant seasonal and spatial variations: Cd, 0·09–0·57 ppm; Pb, 15–43 ppm; Cu, 12–32 ppm; Mn, 250–1990 ppm and Fe 0·5–5·4%. Reducing conditions leading to diagenetic remobilization in estuarine sediments are proposed to be an important source of dissolved metals for estuarine water. Calculations of dissolved riverine metal transport to the ocean that include estuarine metal input are as much as 40 times greater than when estuarine processes are ignored.  相似文献   

13.
Orchestia gammarellus (Pallas) will tolerate temperatures from 0°C to c. 30°C but dies in < 1 h at 35°C. Both small and large animals survive > 96 h in water (aerated) between 1 and 60%(.) salinity. In distilled water and 100%(.) brine death occurred after 8–24 h. In fully saline water, pH reduction to c. 3·3 is tolerated. Highly alkaline (pH 11–13) conditions in low salinity media are rapidly fatal. Ammonium concentrations (in fully saline water) some five orders of magnitude higher than normal for seawater are tolerated, reflecting the enhanced ammonium concentration encountered in rotting weed beds. Cl− ion concentration equivalent to that in normal seawater will not support O. gammarellus in the absence of Na+ ions. High NO3− concentrations (> 100 mg NO3− litre−1) are fatal in < 24 h. A large range of NaCl concentrations is tolerated (one to two orders of magnitude dilution) by immersed animals. Animals will live longer in air, however, when fed low Na+ food than when immersed in seawater diluted to an equivalent ion strength. Ca2+ and K+ ions cannot substitute for Na+. Orchestia gammarellus will, however, tolerate wide variations in the ratio of Na+:K+ ions (i.e to a shift from 30:1 to 0·3.1) in hypo-osmotic media. At 10°C it will survive c. 5 h of anoxia. It will penetrate into strongly reducing conditions (− 318 mV) even with access to better oxygenated conditions. In nature, behavioural avoidance probably ensures that O. gammarellus does not encounter many of these parameters at acutely limiting values. That this species is so tolerant, however, bears on the evolutionary adaptability of talitrid amphipods to non-marine conditions. Desiccation sensitivity and Na+ ion dependency are the species' most important barriers to life on land.  相似文献   

14.
The bivalves Protothaca staminea and Mytilus edulis were exposed to five depths of decomposing bark from an active log transfer facility for 13–96 days in a field experiment at Auke Bay, Alaska. Survival and condition of both species was inversely related to depth and duration of bark coverage. As little as 6 cm of bark reduced survival; survival declined most rapidly between 10 and 15 cm of bark. The depths of bark under which half the animals died after 96 days of exposure were 12·8 ± 1·6 cm for P. staminea and 10·9 ± 1·5 cm for M. edulis. Interstitial water in the bark deposits had low concentrations of dissolved O2 (2·5–5·3 mg/liter) and elevated concentrations of hydrogen sulfide (1·0–8·1 mg/liter total sulfide) and ammonia (46–131 μg-at N/liter) compared to the surface water from the control treatment. Survival of P. staminea and M. edulis was inversely related to concentrations of hydrogen sulfide and ammonia and directly related to dissolved O2 concentrations.  相似文献   

15.
Low levels of dissolved oil hydrocarbons are demonstrated to produce sublethal effects on the early cod larval stages. These effects are discussed in relation to larval survival through the first critical stages.Continuous exposure of cod eggs and larvae to 0·05 and 0·25 ppm of the water-soluble fraction (WSF) of Ekofisk crude oil for 14 days caused significant reduction in growth and change in neutral buoyancy. The larvae exposed to 0·25 ppm showed malformation in the foremost part of the head and jaw, which reduced their ability to capture prey organisms at first feeding.  相似文献   

16.
The rotatory-flow technique was applied to cod, Gadus morrhua L., from different regions of Scandinavia. Fish from three area (Vikanes, Norway and Kristineberg and Gårdby, Sweden) in which the water is relatively unpolluted did not differ significantly as to the mean reaction quotient. Experiments to determine the fitness of cod from the Kristineberg and Stenungsund areas were conducted during a 29-month period. The mean reaction quotients for Stenungsund cod were significantly lower than those for Kristineberg cod for all the experiments except for the final tests conducted during November, 1975. They did not vary inversely to the amounts of monomethyl mercury, PCB and DDT analysed in the trunk muscles of tested specimens.In order to determine the effect of these toxic compounds on the efficiency of the fish from Kristineberg, cod were treated with sublethal doses given by oral intubation. A significant decrease in the reaction quotients was obtained with the lowest level of DDT used (1 ppm), the decreases in the reaction quotients being linearly correlated (r = 0·60) with the amount of DDT in the muscle tissue (mean value 0·36 ppm wet tissue). For PCB and mercury the corresponding mean levels in muscles were 1·8 and 1·5 ppm, respectively. These amounts are about 10, 30 and 75 times greater, respectively, than those found in the Stenungsund cod. It is, however, doubtful whether the distribution of the toxicants within the fish body corresponded to that occurring in the sea.  相似文献   

17.
Editorial     
A flow-through system for exposure of seagrass to pollutants is described. Sea water with dissolved atrazine or PCP (pentachlorophenol) was pumped through a sealed 2-litre volume glass exposure vessel that contained either whole plants or leaves of Thalassia testudinum. Effects of the compounds on oxygen evolution and uptake by leaves were measured after exposure for 40 and 88 h. Rate of oxygen evolution was depressed strongly after 40 h by 1 ppm of atrazine or PCP. The rate of oxygen uptake was slightly depressed by atrazine but strongly depressed by PCP. Photosynthesis/respiration ratios were depressed to less than one by 1 ppm of atrazine or PCP and by 0·5 ppm atrazine. EC50 values based upon depression of oxygen evolution after 40 hours exposure were: atrazine, 0·32 ppm PCP, 0·74 ppm. The data suggest that leaves may recover from, or adapt to, the presence of either toxicant.  相似文献   

18.
To determine one possible mechanism of hydrocarbon toxicity, studies were carried out to establish: (a) the availability of hydrocarbons from sea water to the crab haemolymph, (b) the effects on respiration and (c) the possible effects on haemocyanin—O2 binding characteristics in oiled crabs.Crabs incubated in 14C-naphthalene labelled oiled sea water (Kuwait crude) readily accumulated the isotope into the haemolymph, in concentrations exceeding those in the surrounding sea water medium with one-hour bioconcentration factors from 2·53 to 23·51. Respiration, as measured by uptake of O2 from the respirometer sea water, was 12·5% lower in crabs held in 11·0 ppm Kuwait crude/sea water than in the same animals when held in unoiled sea water. Respiration levels returned to preoiling levels when the oiled sea water was replaced with fresh non-oiled sea water.Despite the observed effects of oiled sea water on respiration, the haemocyanin—O2 binding potential, as well as the structural integrity of haemocyanin (as determined by its UV absorption spectrum, sub-unit dissociation and serum-free Cu++ levels), remained unaltered. The results suggest that disruption of blood-oxygen transport via disruption of haemocyanin—O2 binding as one possible mechanism of hydrocarbon toxicity is unlikely and that other alternatives must be considered.  相似文献   

19.
The effects of 1-naphthol, the first hydrolytic product of the insecticide Sevin®, have been studied on the estuarine bivalve Scrobicularia. Median lethal times for 5 and 10 mg l?1 1-naphthol were 15 and 9 days respectively. Final concentrations of 1, 5, 10 and 20 mg l?1 of 1-naphthol resulted in the immediate contraction of the isolated siphon. The contractions were more pronounced at higher concentrations. Application of the same range of concentrations of 1-naphthol to intact Scrobicularia resulted in valve closure and bradycardia. The similarity between the results of median lethal time experiments and the isolated siphonal and behavioural responses of Scrobicularia indicates the feasibility of the use of the isolated siphon preparations to make rapid assessments of environmental stress conditions.  相似文献   

20.
Multiple regression analyses indicate that the most important factors controlling Ag, Cd, Co, Cu, Pb and Zn concentrations in the estuarine bivalve Scrobicularia plana and the polychaete Nereis diversicolor are the concentrations of these metals in surface sediments and the partitioning of sediment-bound metals between different sediment constituents. Extraction of the sediments with 1-n HCl provides more information about the bioavailability of the metals than do extractions with five other techniques. Biologically available Cd and Co in solution contribute significantly to Cd and Co concentrations in both Scrobicularia and Nereis. Concentrations of Ag in Scrobicularia are reduced where Cu concentrations in sediments are high. An unexplained increase in concentrations of Cu in Scrobicularia at specific stations in six estuaries suggests that under certain very anoxic conditions the availability of copper may be exceptionally high.  相似文献   

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