The Energetics of Osmotic Regulation in Brackish- and Fresh-Water Animals

1954 ◽  
Vol 31 (4) ◽  
pp. 618-630 ◽  
Author(s):  
W. T. W. POTTS
Keyword(s):  
Surface Area ◽  
Fresh Water ◽  
Brackish Water ◽  
External Medium ◽  
Urine Concentration ◽  
Marine Animal ◽  
Osmotic Regulation ◽  
Moderate Reduction ◽  
Important Means ◽  
Theoretical Minimum

1. The dynamics of osmoregulation in an ideal semi-permeable animal are discussed. The theoretical minimum osmotic work is evaluated in terms of the surface area of the animal, its permeability and the concentrations of the blood, urine and external medium. 2. It is shown that: (a) The most important means whereby a marine animal entering brackish water can reduce the strain upon its osmoregulatory mechanisms is by reducing the concentration of its blood. (b) In a brackish-water animal the production of urine hypotonic to the blood has only a very small effect upon the osmotic work. (c) In a fresh-water animal the reduction of the urine concentration to the point at which it is isotonic with the medium can reduce the osmotic work by as much as 90%; but even a moderate reduction of the urine concentration, so that the urine is hypotonic to the blood but many times more concentrated than the medium, greatly reduces the osmotic work and is compatible with high osmoregulatory efficiency. 3. These conclusions are discussed with reference to some fresh-water animals.

Osmotic Regulation in Mosquito Larvae

1950 ◽  
Vol 27 (2) ◽  
pp. 145-157 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
External Medium ◽  
Freezing Point ◽  
Anterior Part ◽  
Osmotic Regulation ◽  
Opposite Process ◽  
Normal Environment ◽  
Different Parts

1. The processes of osmotic regulation in the larvae of Aedes aegypti and of A. detritus have been studied by determination of the freezing-point of samples of fluid collected from different parts of the gut. 2. In A. aegypti, kept in fresh water (its normal environment), the fluid passing down the intestine to the rectum is isotonic with the haemolymph. In the rectum it becomes strongly hypotonic before being eliminated. 3. In A. detritus, kept in sea water (its normal environment), the opposite process is observed, the fluid in the rectum becoming hypertonic to the haemolymph and approximately isotonic with the external medium before being eliminated. 4. In A. detritus, which is able to live in dilute media as well as in sea water, the only two specimens from fresh water available for examination were found to have the rectal fluid hypotonic to the haemolymph. 5. The ability of A. detritus, not possessed by A. aegypti, to produce an hypertonic fluid in the rectum is tentatively associated with a region in the anterior part of the rectum and lined with an epithelium distinctly different from that in the remainder of the rectum. This anterior region has not been found in A. aegypti.

Osmotic Regulation in the Crab-Eating Frog (Rana Cancrivora)

1961 ◽  
Vol 38 (3) ◽  
pp. 659-678 ◽  
Author(s):  
MALCOLM S. GORDON ◽  
KNUT SCHMIDT-NIELSEN ◽  
HAMILTON M. KELLY
Keyword(s):  
Fresh Water ◽  
External Medium ◽  
Short Circuit ◽  
Inorganic Ions ◽  
Short Circuit Current ◽  
Water Levels ◽  
Close Relative ◽  
Osmotic Regulation ◽  
Water Frogs ◽  
Nacl Concentration

1. The osmotic and ionic regulatory abilities of adults of the euryhaline crab-eating frog (Rana cancrivora) have been studied. Adult frogs tolerated environmental salinities as high as 28‰ at 30°C. Tadpoles of this form tolerated salinities as high as 39%‰ at the same temperature. 2. Changes in body weight of frogs following transfers to different environmental salinities indicate both that the skin of this frog is permeable to water and that these animals do not swallow large volumes of external medium, even in high salinities. 3. Above salinities of about 9%‰, plasma Δ rises with increasing environmental Δ. Plasma Δ is always higher than environmental Δ. Increases in plasma concentration above fresh-water levels are due partly to increased NaCl concentration (about 40%), partly to increased urea concentration (about 60%). Urea concentrations as high as 0.48 M (2.9%) have been measured. 4. Urinary Δ parallels plasma Δ, but is always lower than plasma Δ. Considerable quantities of urea are lost via the urine, even though urinary urea levels are below plasma levels. 5. Measurements of short-circuit current indicate that active uptake by the skin of inorganic ions continues in R. cancrivora acclimatized to high salinities. 6. R. cancrivora is no less susceptible to water loss by evaporation from the skin than are other amphibians. 7. In preference experiments R. cancrivora chooses salinities below 18%‰, but shows no strong preference for a particular salinity. 8. Similar observations on osmoregulatory mechanisms in a close relative of R. cancrivora, the tiger frog (R. tigerina), show that the latter species is similar to ordinary fresh-water frogs. 9. The striking physiological convergence between R. cancrivora and the elasmo-branch fishes is discussed, as are various possible implications of our data regarding nitrogen metabolism in tadpoles and kidney function in adult frogs.

scholarly journals Content of inorganic solutes in lettuce grown with brackish water in different hydroponic systems

2017 ◽  
Vol 21 (3) ◽  
pp. 150-155 ◽  
Author(s):  
Alide M. W. Cova ◽  
Fabio T. O. de Freitas ◽  
Paula C. Viana ◽  
Maria R. S. Rafael ◽  
André D. de Azevedo Neto ◽  
...  
Keyword(s):  
Fresh Water ◽  
Nutrient Solution ◽  
Brackish Water ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Matter Production ◽  
Water Plant ◽  
Hydroponic Systems ◽  
Inorganic Solutes

ABSTRACT The objective of this study was to evaluate the growth and accumulation of ions in lettuce grown in different hydroponic systems and recirculation frequencies. The experimental design was randomized blocks with 8 treatments and 4 replicates. The evaluated hydroponic systems were Nutrient Flow Technique (NFT) and an adapted Deep Flow Technique (DFT), the latter with recirculation frequencies of 0.25, 2 and 4 h. Both systems used fresh water and brackish water. Plant growth, accumulation of inorganic solutes (Na+, K+, Cl- and NO3-) and the correlation between dry matter production and Na+/K+ and Cl-/NO3- were evaluated. The salinity of the water used to prepare the nutrient solution caused decrease in growth and K+ and NO3- levels, and increased contents of Na+ and Cl- in the plants. When using fresh water the highest dry matter production was obtained in the NFT system. In case of brackish water the adapted DFT system increased the production, in relation to NFT system (at same recirculation frequency: 0.25 h). It was found that the choice of the type of hydroponic system and recirculation interval for the cultivation of lettuce depends on the quality of the water used to prepare the nutrient solution.

Sodium Regulation in the Amphipod Gammarus Duebeni Lilljeborg form Freshwater Localities in Ireland

1968 ◽  
Vol 48 (2) ◽  
pp. 339-358
Author(s):  
D. W. SUTCLIFFE ◽  
J. SHAW
Keyword(s):  
Fresh Water ◽  
Loss Rate ◽  
Sea Water ◽  
Detailed Comparison ◽  
Urine Concentration ◽  
Sodium Influx ◽  
Fresh Waters ◽  
Low Sodium ◽  
Characteristic Features ◽  
Sodium Regulation

1. A quantitative study of sodium influx and loss was made on populations of Gammarus duebeni obtained from four freshwater localities in Ireland. 2. Characteristic features of sodium regulation in animals from the four localities were as follows, (a) The sodium influx increases gradually with increasing external sodium concentrations, but a maximum (saturation) level is abruptly reached at an external concentration of 1-2 mM/l. and the transporting system is half saturated at about 0.5 mM/l. sodium, (b) Over the range of sodium concentrations found in fresh waters a low rate of sodium uptake is sufficient to balance sodium losses at concentrations down to between 0.5 and 0.25 mM/l. At lower concentrations the influx is increased and the loss rate is reduced. (c) Calculations suggest that hypotonic urine containing approximately 40 mM/l sodium is produced at external concentrations ranging from fresh water to 40 % sea water. At external concentrations below 0.25 mM/l. sodium the urine concentration is probably reduced to well below 40 mM/l. sodium. 3. A detailed comparison is made of sodium regulation at external concentrations ranging between 0.07 and 1 mM/l. sodium in G. duebeni from fresh water in Ireland and from fresh water and brackish water in Britain. It is suggested that G. duebeni in Ireland constitutes a distinct physiological race adapted for living in fresh waters with relatively low sodium concentrations.

scholarly journals Adaptational Responses of Rainbow Trout to Lowered External Nacl Concentration: Contribution of the Branchial Chloride Cell

1989 ◽  
Vol 147 (1) ◽  
pp. 147-168 ◽  
Author(s):  
STEVE F. PERRY ◽  
PIERRE LAURENT
Keyword(s):  
Rainbow Trout ◽  
Surface Area ◽  
Fresh Water ◽  
Primary Response ◽  
Chloride Cell ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Apical Surface ◽  
Ionic Fluxes ◽  
Area 5

1. Whole-body ionic fluxes and gill chloride cell (CC) morphology were monitored in rainbow trout (Salmo gairdneri) exposed acutely or chronically to natural fresh water (NFW; [Na+]=0.120 mmoll−1; [Cr]=0.164 mmoll−1) or artificially prepared fresh water with reduced [NaCl] (AFW; [Na+]=0.017 mmoll−1; [CT]=0.014 mmoll−1). 2. Net fluxes of Na+ (JnetNa) and Cl− (JnetCl) became extremely negative (indicating net NaCl loss to the environment) upon immediate exposure to AFW exclusively as a result of reduced NaCl influx (JinNa and JinNa). JnetNa and JnetCl were gradually restored to control rates during prolonged (30 days) exposure to AFW. 3. The restoration of JnetCl in AFW was due both to increased JinCl and to reduced Cl− efflux (JoutCl) whereas the primary response contributing to the restoration of JnetNa a t was an increase of JNain. 4. The total apical surface area of branchial CCs exposed to the external environment increased markedly after 24 h in AFW and remained elevated for 1 month as a consequence of enlargement of individual CCs and, to a lesser extent, increased CC density. JinNa and JinNa were correlated significantly with total CC apical surface area. 5. Plasma cortisol levels rose transiently in fish exposed to AFW. Treatment of NFW-adapted fish with cortisol for 10 days (a protocol known to cause CC proliferation) caused pronounced increases in JinCl and JinNa, as measured in both NFW and AFW. 6. These results suggest that an important adaptational response of rainbow trout to low environmental [NaCl] is cortisol-mediated enlargement of branchial epithelial CCs which, in turn, enhances the NaCl-transporting capacity of the gill as a result of the proliferation of Na+ and Cl− transport sites.

scholarly journals Aedes Aegypti: Energetics of Osmoregulation

1982 ◽  
Vol 101 (1) ◽  
pp. 135-141 ◽  
Author(s):  
H.A. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Energy Cost ◽  
Sea Water ◽  
External Medium ◽  
Minimum Energy ◽  
Body Volume ◽  
Wet Weight ◽  
Minimum Energy Cost ◽  
Anal Papillae ◽  
Theoretical Minimum

1. Oxygen consumption of A. aegypti larvae, about 210 mul l g−1 tissue wet weight h−1, does not change when the salinity of the environment is changed. The number of mitochondria in the anal papillae, a salt-absorbing epithelium, increases as the external medium is diluted. There is no difference in oxygen consumption between isolated anal papillae in 0, 2 and 20% sea water. The papillae represent about 5% of body volume and their oxygen consumption is about 2% of the animal's total. The theoretical minimum energy cost of osmoregulation is four orders of magnitude smaller than the measured figure for the anal papillae alone. Osmoregulatory phenomena which would explain the recorded observations are discussed.

XII.—The Brackish-water Lochs of North Uist

1937 ◽  
Vol 56 ◽  
pp. 169-195 ◽  
Author(s):  
A. T. Nicol
Keyword(s):  
Fresh Water ◽  
Brackish Water

About the year 1695 Martin Martin visited the Hebrides, and of the Island of North Uist he writes, “There is such a number of fresh water lakes here as can hardly be believed. … They are generally well stocked with trout and eels and some of them with salmon, and, which is yet more strange, cod, ling, mackerel, etc., are taken in these lakes into which they are brought by the spring tides.” This old reference suggested that the brackish-water fauna of the Hebrides might be of considerable interest and extent. Consequently I spent part of the summers of 1933 and 1935 in North Uist in order to study the fauna of the lochs and the conditions under which the animals were living.

Application of geothermal energy for heating and fresh water production in a brackish water greenhouse desalination unit: A case study from Algeria

2010 ◽  
Vol 14 (1) ◽  
pp. 512-517 ◽  
Author(s):  
Hacene Mahmoudi ◽  
Nawel Spahis ◽  
Mattheus F. Goosen ◽  
Noreddine Ghaffour ◽  
Nadjib Drouiche ◽  
...  
Keyword(s):  
Fresh Water ◽  
Brackish Water ◽  
Geothermal Energy ◽  
Water Production

scholarly journals Response of Water-Salt Migration to Brackish Water Irrigation with Different Irrigation Intervals and Sequences

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2089 ◽  
Author(s):  
Zhu ◽  
Yang ◽  
Sun ◽  
Zhang
Keyword(s):  
Fresh Water ◽  
Brackish Water ◽  
Irrigation Treatment ◽  
Water Infiltration ◽  
Laboratory Simulation ◽  
Irrigation Interval ◽  
Significant Difference ◽  
Soil Desalination ◽  
The Mean ◽  
Irrigation Treatments

Establishing methods for scientific and rational use of brackish water resources is the key to farmland irrigation in the Yellow River Delta region of China. In this study, we conducted laboratory simulation experiments with soil columns and monitored the changes in water infiltration and salt distribution under eight irrigation treatments, including four intervals (0, 30, 60, and 90 min between irrigations) and two sequences (brackish-brackish-fresh water and brackish-fresh-brackish water). The results showed that the duration of water infiltration into the soil was higher under intermittent irrigation than continuous irrigation, with the highest value recorded at the 90-min irrigation interval. There was no significant difference in the mean soil water content between the brackish-brackish-fresh water (28.01–29.71%) and brackish-fresh-brackish water (28.85–29.98%) irrigation treatments. However, the mean soil desalination rate of the brackish-brackish-fresh irrigation treatment (42.51–46.83%) was higher than that of the brackish-fresh-brackish irrigation treatment (39.48–46.47%), and a much higher soil desalination rate was observed at the 90-min irrigation interval, compared with the other intervals. In conclusion, brackish-brackish-fresh water irrigation at longer time intervals (e.g., 90 min between irrigations) is conducive to reduce soil salt content in the surface soil in the study region.

Sign in / Sign up

Export Citation Format

Share Document