Small Volumes Of Seawater Research Articles

Determination of aluminum, lead, and vanadium in North Atlantic seawater after coprecipitation with ferric hydroxide

Recent advances in instrumentation technology for atomic absorption spectrometry using the heated graphite furnace now make it possible to analyze for many trace metals after concentration from small volumes (50-200 mL) of seawater when the major ions are eliminated. Coprecipitation with ferric hydroxide requires few reagents and minimal sample manipulation, suggesting its use as a routine preconcentration procedure for the analysis of seawater. The separation of Al, Pb, and V from small volumes of seawater is described along with analysis by neutron activation or atomatic absorption spectrometry. 18 references, 3 tables.

A study of feeding behaviour in Temora longicornis (Müller) (Crustacea:Copepoda)

The feeding behaviour of Temora longicornis (Müller) was studied using a suction restraint technique in large volumes of sea water. Observations and records were made with a video-tape recorder and Temora cephalic limb beat movements recorded with a micro-impedance pneumograph. The classical copepod feeding swirls, shown for other calanoid copepods, were shown to be artefacts of the constraints imposed by small volumes of sea water. No feeding swirls were seen when sea water flowed past the animals at a speed equivalent to that of slow swimming by copepods. Food particles were brought to the restraining surfaces of the cephalic appendages from in front, and not behind, the maxillipedes. Female T. longicornis were shown to increase their limb beat frequency and amplitude when presented with patches of the diatom Skeletonema. Such an increase in limb beat movement would suggest that Temora could adjust its feeding speed to the availability of algal food in the sea water.

The Determination of Heavy Metals in the Ligurian Sea. III. Distribution of Copper, Iron, and Nickel in the 0–200 Metre Layer in Open Sea

Abstract Dissolved Cu, Fe and Ni were determined in sea water samples from 9 stations in the Ligurian Sea located along the two traverses Imperia-Capo Corso and Nice-Calvi and at depths between 0 and 200 m. The samples were preconcentrated from small volumes of sea water by complexation with ammonium pyrrolidine-dithiocarbammate (APDC), extraction with CCl4 and determination by AAS with electrothermal atomisation. The geographical distribution shows that in the central part of the inner traverse there is a maximum of Cu and Fe concentration; the vertical distribution shows no significant depletion of the dissolved elements in the epithalassa. The results allow for a first approach to the more general problem of the distribution of the trace elements in the Ligurian Sea.

An ion-exchange technique for concentrating ammonia from small volumes of seawater

An ion-exchange technique was used to concentrate ammonia from seawater. Precipitation of bivalent cations, prior to concentration, reduced the variability of ammonia recovery from the ion-exchange column and lengthened column life. Analysis of the eluate was by the phenolhypochlorite reaction. The method was designed for use with small seawater samples (>10ml) and has the advantage that it can be adapted for use with small volumes of seawater with no loss in sensitivity. In a 10 ml seawater example NH 3-N concentrations of 10–150 μg l −1 were accurately determined.

The respiratory response to asphyxia of Typhlogobius californiensis (Teleostei: Gobiidae) and some related gobies.

1. The respiratory, metabolic, and behavioral responses to asphyxia of three gobiid fishes are compared. Adult specimens of Typhlogobius californiensis and Gillichthys mirabilis are subject to hypoxic stress in their natural habitats, while Coryphopterus nicholsii generally is not.2. Oxygen tensions in burrows of the ghost shrimp Callianassa affinis, commensal host of Typhlogobius, fall rapidly to nearly anoxic levels following exposure of the burrow openings by the outgoing tide.3. The resting oxygen consumption of Typhlogobius is extremely low; the one gram intercept for the wet weight-oxygen uptake regression is 17 µl O2/g/hr. The other two species consume oxygen 3 to 5 times as rapidly at rest.4. Resting specimens of Typhlogobius are capable of maintaining a constant rate of oxygen uptake down to a critical ambient oxygen tension of 9-16 mm Hg. Gillichthys and Coryphopterus are capable of regulating oxygen uptake down to critical levels of 16-25 mm Hg and 19-28 mm Hg respectively.5. Both Typhlogobius and Gillichthys metabolize gasbladder oxygen during the initial few hours of asphyxia.6. Typhlogobius accumulates lactate ion during periods of prolonged asphyxia, indicating that maintenance energy is derived from anaerobic metabolism. The 95% confidence limits for the rate of lactate accumulation are energetically equivalent to 33% to 52% of the respirometrically measured aerobic metabolic rate.7. The survival time of Typhlogobius in deoxygenated seawater varies with the volume of seawater. In very small volumes of seawater (< 10-20 ml), survival time is less than 24 hours. In larger volumes of seawater, survival time asymptotically approaches 80 to 100 hours. The decreased asphyxial survival time in small volumes of seawater may result from rapid accumulation of an excreted acid byproduct of anaerobic metabolism.Gillichthys survives exposure to deoxygenated seawater for a relatively short period of time; survival times varied from 6.5 to 12.5 hours and were independent of seawater volume. Coryphopterus survives anoxia only 28 to 42 minutes.8. It is hypothesized that the ability of Typhlogobius to function as a facultative anaerobe may be related to the low energy demand of the brain, to vascular adaptations which facilitate the exchange of metabolites between brain and circulating blood, and to an ability to excrete the acid by-product(s) of anaerobic metabolism.

Sea Water Drinking and Water Flux in Starved and in Fed Harbor Seals, Phoca vitulina

Harbor seals maintained in sea water were either starved or fed graded amounts of herring of known water and total chloride contents. Total body water and exchangeable chloride in the seals were measured by initial dilution of injected tritiated water and Na36Cl. The decline in specific activities of plasma water and chloride was then followed for 12 to 14 days. Average daily fluxes of water and Cl− were calculated. Sea water ingestion was calculated from the daily chloride flux and the chloride contents of the food and sea water. In five animals fed from 0 to 1500 g herring/day, total water flux was linearly related to food intake and ranged from 500 to 1590 ml water per day. In the same animals ingested sea water and metabolic plus inspired water were also linearly related to food intake, and ranged respectively from 35 to 140 ml and 470 to 625 ml water per day. The data provide definitive evidence that starving Harbor seals derive sufficient oxidative water to satisfy the major part of their needs and that they drink very little sea water. In feeding seals the sum of preformed water and metabolic plus inspired water accounts for about 90% of the total water flux, which is comparable in magnitude to that of most terrestrial mammals. The small volume of sea water ingested by Harbor seals, and its linear relationship to food intake, show compellingly that sea water ingestion is coincident to swallowing food under water rather than due to deliberate drinking.

Potassium movement in relation to nerve activity.

The depolarization of crab nerve during repetitive stimulation is unaffected by the presence of glucose or by an increase in the calcium content of the medium. It is increased in both amplitude and rate by veratrine; in the presence of this alkaloid mixture the rate but not the magnitude of the depolarization is increased by an elevation in the calcium concentration. Repolarization following stimulation is unaltered by glucose and accelerated by a greater calcium concentration. Veratrine increases both the amplitude and the time constant of repolarization; its effect on the time constant is counteracted by an elevation of the calcium in the medium. Potassium released during stimulation and its reabsorption following activity have been observed by analyses of small volumes of sea water in contact with crab nerve. Under the conditions employed 3 x 10(-8) microM potassium is liberated per impulse per gm. wet weight of nerve. This loss is increased by low concentrations of veratrine, which also increase the amount reabsorbed during recovery. The depletion of potassium from the medium is appreciably less if the potassium previously released during activity has not been removed. Inexcitability resulting from anoxia can be washed away with oxygen-free solution-rapidly and completely in the case of the squid axon, slowly and incompletely in crab nerve. The potassium shifts are in the proper direction and of the correct order of magnitude to account for the negative and positive after-potentials in terms of potassium accumulation or depletion in the extracellular space.

Potassium retention in crab nerve.

Spectrophotometric determinations of the potassium content of small volumes of sea water brought into contact with crab nerves over half-hour intervals demonstrate (a) a continuous loss of potassium from the fibers while at rest in oxygen; (b) an appreciable increase in the leakage during anoxia; (c) a reabsorption of potassium during postanoxic recovery; and (d) a reduction in the amplitude of the anoxic and postanoxic changes in the presence of glucose.

OBSERVATIONS ON THE MULTIPLICATION OF BACTERIA IN DIFFERENT VOLUMES OF STORED SEA WATER AND THE INFLUENCE OF OXYGEN TENSION AND SOLID SURFACES

The storage of sea water is accompanied by a great increase in the number of bacteria and a decrease in bacterial species.Appreciably more bacteria per cc. appear in small volumes of sea water than in large volumes of identical water.Although the oxygen content of sea water is a factor which influences the activity of bacteria, it does not account for the denser bacterial populations which appear in the smaller volumes.The favorable influence of small volumes is attributed to the contact of the water with the larger solid surface area in the small receptacles. Between ten and a hundred million bacteria per cc. have been demonstrated in sea water stored in sand which presents an enormous surface area whereas less than three hundred thousand bacteria per cc. appearing similar water stored in 10-liter bottles presenting relatively little surface area.The beneficial effect of small volumes and their large surface areas occurs only in dilute nutrient solutions. Upon the addition of 10 to 100 mgm. of organic matter to sea water, the volume effects disappear. Solid surfaces may serve as a resting place for periphytes, they may help concentrate the nutrients by adsorption or otherwise, or they may favor bacterial enzymatic activity and the absorption of metabolites.