Papers by Judith McDowell
Estuarine and Coastal Marine Science, 1979
The toxicity of free chlorine and combined chlorine as chloramine to the rotifer Brachiunus plica... more The toxicity of free chlorine and combined chlorine as chloramine to the rotifer Brachiunus plicatilis at three exposure temperatures has been evaluated. Chloramine was more toxic to rotifers than the free halogen form with LC,, values for 3o-min exposures at zo "C of 0.35 mg 1-l applied chloramine and 1.20 mg 1-i applied free chlorine, 0.02 mg 1-i and o-18 mg 1-i residual levels, respectively. The synergistic effect of temperature on the toxicity of both halogen forms was also noted. Rotifers surviving exposure to either halogen toxicant had significantly lower filtration rates and egg production rates than control animals. The reduced reproductive rates were not sustained by the second generation of rotifers and it appears that exposure to free chlorine or chloramine does not result in a permanent alteration in the reproductive potential of rotifer populations.
Estuarine and Coastal Marine Science, 1977
The differential effects of free chlorine and chloramine on three species of juvenile marine fish... more The differential effects of free chlorine and chloramine on three species of juvenile marine fish have been investigated in continuous flow bioassay units, The toxicity of both chlorine forms to winter flounder, Pseudopleuronectes americanus, scup, Stenotomus vwsicolor, and killifish, Fundulus heteroclitus, appeared to be a threshold effect: an abrupt increase in mortality was observed over a narrow range of toxicant concentrations. The three species were similar in their responses to free chlorine, the more toxic of the two chlorine forms. However, there was a difference in chloramine toxicity among the three species tested; killifish were more susceptible than either of the other two species, probably reflecting differences in metabolic regulation or uptake rates. Behavioral aberrations-distended gills and erratic swimming behavior-of winter flounder and scup and significant reductions in standard respiration rates of killifish were observed with exposure to chlorine or chloramine concentrations approaching lethal levels.
Water Research, 1976
The differential effects of free chlorine and chloramine on stage I larvae of the American lobste... more The differential effects of free chlorine and chloramine on stage I larvae of the American lobster Homarus americanus have been investigated in continuous flow bioassay units. Applied chloramine was more toxic than corresponding concentrations of applied free chlorine to lobster larvae with estimated LCso values at 25 ° of 16.30 mg/l applied free chlorine and 2.02 mg/1 applied chloramine. The synergistic effect of temperature on the toxicity of both free chlorine and chloramine has also been demonstrated. Exposure to applied free chlorine at 20 ° resulted in no significant mortality of test organisms, whereas exposure at 30 ° resulted in an estimated LCs0 value of 2.50mg/1. Applied chloramine was considerably more toxic with an estimated LC50 value at 20 ° of 4.08 mg/1 and at 30 ° of 0.56 mg/1. The action of each toxicant appeared to be an alteration of standard metabolic activity as revealed by changes in respiration rates during and after exposure to applied free chlorine and chloramine. Initial respiratory stress was detected during exposure to 0.05 mg/l applied chloramine and 5.00 mg/1 applied free chlorine. Reductions in respiration rates 48 h after exposure were observed with exposure to all concentrations tested, similar results being obtained following exposure to 0.05 mg/1 applied chloramine and 0.10 mg/1 applied free chlorine. These results are indicative of the need for information in addition to that obtained in standard bioassays for an adequate assessment of chlorine toxicity. The apparent chlorine demand of the seawater used in this study was determined after removal of particulate and dissolved organics and ammonia. Approximately 18% of the applied level of free chlorine and chloramine was recovered as residuals, measured by amperometric titration; however, no reason for this low recovery has been determined. Until it has been established that undetected chlorine and chloramine in seawater do not result in the production of toxic compounds, both applied and residual levels should be reported in toxicity studies.
Water Research, 1979
... CHLORINE DISAPPEARANCE IN SEA-WATER* JOEL C. GOLDMAN, HELI'N L. QI.JINBY andJUDITH M. CA... more ... CHLORINE DISAPPEARANCE IN SEA-WATER* JOEL C. GOLDMAN, HELI'N L. QI.JINBY andJUDITH M. CAPUZZO Woods Hole Oceanographic ... artificial sea-water were greatly reduced, indicating that the lost applied chlorine was associated with the bromine chemical system ...
Marine Pollution Bulletin, 1979
Marine Pollution Bulletin, 1977
... Chlorinated Cooling Waters in the Marine Environment: Development of Effluent GuidelinesJUDIT... more ... Chlorinated Cooling Waters in the Marine Environment: Development of Effluent GuidelinesJUDITH M. CAPUZZO, JOEL C. GOLDMAN, JOHN A ... compounds, or placed in microrespirometer units and were allowed to result in the formation of its bromine counterparts acclimate ...
Marine Geology, 1973
... In Piper's work (1971) on an anoxic fjord, chromium was associated with suspended ma... more ... In Piper's work (1971) on an anoxic fjord, chromium was associated with suspended matter only in the upper 20 m of the water column where oxygenated waters prevailed. ... Folk, RL, 1965. Petrology of Sedimentary Rocks. Hemphill's, Austin, Texas, 159 pp. Fr6hlich, F., 1960. ...
Marine Environmental Research, 1985
Marine Environmental Research, 1989
The concentrations of individual chlorobiphenyl congeners were measured in the mussel Mytilus edu... more The concentrations of individual chlorobiphenyl congeners were measured in the mussel Mytilus edulis transplanted to several stations in Buzzards Bay and Nantucket Sound, MA (USA). Individual stations represented a gradient of chemical contamination and the sampling period ...
Marine Environmental Research, 1988
Marine Environmental Research, 1984
ABSTRACT
Marine Biology, 1992
Solemya borealis Totten was collected from anoxic sediments in Buzzards Bay, Massachusetts in Apr... more Solemya borealis Totten was collected from anoxic sediments in Buzzards Bay, Massachusetts in April and July 1989 and examined for the presence of symbiotic, chemoautotrophic bacteria. In addition, sediment cores collected at the same site were analyzed throughout the year, to provide a detailed description of the S. borealis habitat. Here we present structural, enzymatic, biochemical, and stable isotope data which suggests that S. borealis, like the related species Solemya velum Say and Solemya reidi Bernard, contains high concentrations of symbiotic chemoautotrophic bacteria in gill bacteriocytes which play a significant role in nutrition. Transmission electron microscopy revealed the presence of rod-shaped cells, which resemble Gram-negative bacteria, within gill epithelial cells. Ribulose-l,5-bisphosphate carboxylase activity in cell-free extracts of S. borealis gill tissue was comparable with that found in other invertebrate-chemoautotroph symbioses. Very negative 634S ratios (-32.6 to-15.7 %o) suggest the utilization of porewater sulfides as both an energy and a sulfur source for the symbionts. Carbon and nitrogen stable isotope ratios were extremely negative (61ac =-32 to-34.6%o, 615N =-9.7 to-8.6%o), similar to those of other bivalve-chemoautotroph symbioses. High concentrations of cis-vaccenic acid, a fatty acid previously found in other invertebrate-chemoautotroph symbioses, were found in all the major lipid classes of the gills of S. borealis. The stable isotope ratios and lipid composition of S. borealis suggest that most of this bivalve's nutritional requirements are supplied by bacterial endosymbionts. High levels of taurine in the free amino acid pool of S. borealis suggest the existence of unusual amino acid metabolic pathways which may be the result of endosymbiont activity. The S. borealis specimens were found in relatively shallow water sediments dominated by silts and clays. The sediments contain high concentrations of organic carbon and nitrogen, exhibit limited oxygen pene
Limnology and Oceanography, 1989
Notes 249 Limnol. Oceanogr., 34(1), 1989, 249-255 © 1989, by the American Society of Limnology an... more Notes 249 Limnol. Oceanogr., 34(1), 1989, 249-255 © 1989, by the American Society of Limnology and Oceanography, Inc. The role of endosymbiotic bacteria in the nutrition of Solemya velum: Evidence from a stable isotope analysis of endosymbionts and host Abstract—C, ...
Journal of Plankton Research, 1990
Protozoa are an important component of both the nano-and microplankton in marine and freshwater e... more Protozoa are an important component of both the nano-and microplankton in marine and freshwater environments and are preyed upon by zooplankton, including suspension-feeding cope pods, some gelatinous zoopiankters and some first-feeding fish larvae. The clearance rates of suspension-feeding zooplankton for ciliates, in particular, are higher than for most phytoplankton. For at least some suspension-feeding zooplankton, protozoans are calculated to be quantitatively an important component of the diet during certain seasons. In laboratory studies, protozoan components in the diet appear to enhance growth and survival of certain life-history stages or enhance fecundity. These data suggest that protozoans are qualitatively as well as quantitatively important in the diets of marine zooplankton. Most studies of predation on Protozoa have focused on the euphotic zone in nearshore waters. Predation on Protozoa is expected, however, to be particularly important both quantitatively and qualitatively in marine environments and seasons in which primary production is dominated by cells <5 |im in size, such as nearshore environments after the spring phytoplankton bloom, in oligotrophic waters, and in environments dominated by detritusdominated food webs, such as the deep sea. In detritus-dominated food webs, Protozoa may be a source of essential nutrients and may thus facilitate utilization of bacterial and detrital carbon by metazoan plankton.
Journal of Experimental Marine Biology and Ecology, 1990
Activities of digestive protease, lipase, and amylase from the foregut and midgut gland were meas... more Activities of digestive protease, lipase, and amylase from the foregut and midgut gland were measured during the course of early development in the American lobster Homarus americanus Mihre Edwards. Total enzyme activities were very low among embryos sampled 3 days prior to hatching Protease and amylase activities increased slightly at the time of hatching and again during larval Stage I; lipaae activity did not change. Activity of the three enzymes more than doubled among Stage II larvae and although there were slight increases in enzyme activities during Stage III, they were not significant. Protease activity peaked during Stage IV, whereas Iipase and amylase activities were greatest among Stage V juveniles. Different patterns were observed when specific enzyme activities (normaliied on the basis of protein) are examined. Specific activities of the three enzymes were very low in embryos just prior to hatching and increased slightly during the hatching process. During Stage I, the specific activity of protease doubled, lipase specific activity increased by a factor of 10, and that of amylase increased slightly. Activities of both protease and amylase more than doubled in Stage II larvae; in general, there were no significant differences in specific activities measured in Stages II through V. Lipase specific activity did not change sibilantly among Stages I through V. The increase in enzyme activities among the hatching stages correlates well with morphologiical changes observed in the midgut gland (hepatopancreas), specifically in regard to the presence of enzyme-producing B-cells. Changes in enzyme activities among the postmetamorphic Stages IV and V may be related to changes in body form, habitat, or patterns ofenergy storage and utilization. Lobster larvae normally hatch during early summer but embryonic development can be accelerated in the laboratory by maintenance at high (21 'C) rather than ambient temperature. Temperature conditions during embryonic development, however, had no effect on digestive enzyme activities of larvae that were induced to hatch out of season.
Journal of Experimental Marine Biology and Ecology, 1990
The biochemical composition of a subtropical bivalve, the turkey-wing mussel Arca zebra, was exam... more The biochemical composition of a subtropical bivalve, the turkey-wing mussel Arca zebra, was examined in specimens deployed along two contaminant gradients (Castle Harbour and Hamilton Harbour) in Bermuda. Pooled homogenized samples of the mussel were analysed for protein, ash, total lipid and lipid-class composition. The biochemical composition of A. zebra was similar to that observed in other bivalves that rely on glycogen as their primary energy substratum. Differences were noted in the lipid content and composition in mussels deployed in the two harbours. These differences suggest that Hamilton Harbour has higher food availability than Castle Harbour and so the A. zebra from Hamilton Harbour were in better physiological condition as indicated by higher lipid levels, primarily neutral lipids. The biochemical composition of the mussels provides no evidence that Castle Harbour is impacted by contaminants at a local dumpsite. Mussels deployed at Hamilton Harbour had increasing neutral lipid levels along an increasing contaminant gradient, a pattern observed previously in bivalves impacted by anthropogenic inputs to their environment. These changes may indicate impaired mobilization of free fatty acids from the neutral to polar lipid pools, or possible gonadal resorption following exposure to lipophilic contaminants.
Journal of Experimental Marine Biology and Ecology, 1979
The weight-specific respiration rates of fed and starved lobsters and the ammonia excretion rates... more The weight-specific respiration rates of fed and starved lobsters and the ammonia excretion rates of fed lobsters increased with each larval stage (I through IV) and decreased with the first postlarval stage (V). The rate of change in metabolic rates was greater than the rate of change of ...
Helgoländer Meeresuntersuchungen, 1980
The relative importance of thermal, mechanical and biocidal stresses to marine zooplankton entrai... more The relative importance of thermal, mechanical and biocidal stresses to marine zooplankton entrained in cooling waters from coastal power-plant operations is dependent on specific features of power-plant design and siting. Toxic effects of power-plant operations will vary with (1) the degree of mechanical stress induced by pumping velocities of cooling water; (2) the physical and chemical interaction of receiving and discharge waters; (3) the dosage of chlorine or other biocide added to cooling waters for fouling control; (4) the exposure time to stress conditions experienced during passage through condenser conduits and discharge canals~ and (5) the nature of receiving waters, affecting the production and availability of the various halogen toxicants formed upon chlorination of seawater. Because of these variables, the problem of entrainment-induced mortality of zooplankton and the resulting effects on secondary production in receiving waters is difficult to assess. A review of laboratory and field studies addressing these problems is presented and particular emphasis given to the synergistic effect of multiple stresses.
Helgoländer Meeresuntersuchungen, 1985
Effects of feeding and starvation on the moult cycle and on the ultrastructure of hepatopancreas ... more Effects of feeding and starvation on the moult cycle and on the ultrastructure of hepatopancreas cells were studied in StageI lobster larvae (Homarus americanus Milne-Edwards). The relative significance of yolk and first food was quite different in larvae originating from two females. This difference was evident also in the amounts of stored lipid in the R-cells of the larval hepatopancreas. Most larvae from one hatch were, in principle, able to develop exclusively with yolk reserves (without food) to the second instar. The larvae from the second hatch showed lecithotrophic development only to the transition between late intermoult and early premoult (Stages C/D 0 of Drachs's moult cycle) of the first larval instar. When initial starvation in this group lasted for 3 days or more, the point of no return (PNR) was exceeded. After the PNR, consumption of food was still possible, but development ceased in the transition C/D 0 or in late premoult (D3-4). It is suggested that these stages of the moult cycle are critical points were cessation of development and increased mortality are particularly likely in early larval lobsters under nutritional stress. Examination of hepatopancreas R-cells suggested that the PNR is caused by an irreversible loss of the ability to restore lipid reserves depleted during initial starvation. Initial periods of starvation ending before the PNR prolonged mainly Stage D O of the same instar (I). During this delay, structural changes in the R-cells caused by the preceding period of starvation were reversed: reduced lipid inclusions, swollen mitochondria, an increased number of residual bodies indicating autolysis, and a reduction of the microvillous processes. Continually starved larvae which showed lecithotrophic development throughout the first instar and were then re-fed after moulting successfully, had later a prolonged intermoult (Stage C) period in the second instar. This shows that, despite occasional lecithotrophy, food is an important factor in early larval development of the lobster.
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Papers by Judith McDowell