scholarly journals Estabilidade osmótica dos fluídos celômicos de um pepino do mar (Holothuria grisea) e de uma estrela-do-mar (Asterina stellifera) (Echinodermata) expostos ao ar durante a maré baixa: um estudo de campo

2002 ◽  
Vol 31 ◽  
Author(s):  
DENILTON VIDOLIN ◽  
IVONETE A. SANTOS GOUVEA ◽  
CAROLINA A. FREIRE

Animais de entre-marés podem ser expostos ao ar durante a maré baixa, por pelo menos 1-2 horas. Os animais expostos ao ar são susceptíveis a perda de sal e/ou entrada de água durante chuva intensa, ou perda de água pela ação de dessecação do sol. A osmolalidade de amostras de fluido celômico obtidas do pepino-do-mar Holothuria grisea e da estrela-do-mar Asterina stellifera expostas ao ar, ou de animais controles imersos na água do mar adjacente foi determinada. As amostras foram obtidas imediatamente após a exposição ao ar, e novamente após uma hora de exposição ao ar, durante a maré baixa no campo, em tempo nublado, chuvoso, ou ensolarado, na Praia rochosa do Quilombo, Penha, Sul do Brasil. Uma hora de exposição a qualquer das condições climáticas indicadas não alterou a osmolalidade dos fluidos celômicos. Houve pequena redução nas osmolalidades dos fluidos celômicos durante a exposição ao ar com precipitação de chuva. Sugere-se que estes equinodermas possam imediatamente detectar sua exposição ao ar, e possam então reduzir a permeabilidade osmótica de sua parede do corpo, para evitar perda de água para o ar ou entrada de água/saída de sal durante a chuva. ABSTRACT Intertidal animals can be exposed to the air during low tide, for at least 1-2 hours. Animals exposed to the air are subject to salt loss (or water gain) from heavy rains or volume loss from the desiccating action of the sun. Coelomic fluid samples obtained from the sea-cucumber Holothuria grisea and the starfish Asterina stellifera exposed to the air or from control animals submerged in surrounding sea water have been assayed for osmolality. Samples were obtained right after air exposure and again after 1 hour of exposure to the air during low tide in the field, either under cloudy, rainy or sunny weather conditions, in the rocky beach of Quilombo, Penha, Southern Brazil. One hour of exposure to any of the conditions did not change coelomic fluid osmolalities. There was a slight reduction in coelomic fluid osmolalities upon air exposure during rainfall. It is suggested that these echinoderms can somehow immediately detect air exposure and reduce their body wall permeability to avoid water loss or water influx/salt loss during rainfall. RÉSUMÉ Animaux d’entre-marées peuvent êtres exposés a l’air libre pendant le reflux de la marée, pour environ une ou deux heures seulement. Ces animaux, quand exposés a l’air libre, sont susceptibles de perdre du sel et d’absorber de l’eau pendant une période de pluie intense. Par contre, ils peuvent perdre de l’eau si soumis a l’action de dessèchement due a une éxposition au soleil. On a réussi a determiner l’osmolalité d’échantillons du fluide celomique obtenus du Pépin-de-mer Holothuria grisea et de l’Étoile-de-mer Asterina stellifera exposés a l’air libre, e d’animaux-controles immergés dans l’eau de mer voisin. Les échantillons ont été obtenus tout de suite après l’exposition à l’air et, une seconde fois, après une heure d’exposition à l’air libre, pendant la durée de la marée basse, soit sous la pluie, soit au soleil ou soit sous un ciel ombrageux, à la plage rocailleuse de Quilombo, Penha, au sud du Brésil. Une heure d’éxposition à n’importe quelles conditions climatiques indiquées, n’ont pas pu altérer l’osmolalité des fluides celomiques, ce que sugère la conclusion que ces échinodermes peuvent détecter immédiatement sa exposition à l’air libre et peuvent tout de suite réduire la permeabilité osmotique de la membrane que recouvre son corps pour éviter perdre d’eau et, de la même façon, reduire l’absortion de l’eau pendant la pluie. On a observé une petite réduction de fluides celomiques pendant l’exposition a l’air, avec ocurrence de pluie.

1999 ◽  
Vol 202 (7) ◽  
pp. 855-866 ◽  
Author(s):  
K. Hauschild ◽  
W.M. Weber ◽  
W. Clauss ◽  
M.K. Grieshaber

Thiosulphate, the main sulphide detoxification product, is accumulated in the body fluids of the lugworm Arenicola marina. The aim of this study was to elucidate the fate of thiosulphate. Electrophysiological measurements revealed that the transepithelial resistance of body wall sections was 76+/−34 capomega cm2 (mean +/− s.d., N=14), indicating that the body wall of the lugworm is a leaky tissue in which mainly paracellular transport along cell junctions takes place. The body wall was equally permeable from both sides to thiosulphate, the permeability coefficient of which was 1. 31×10(−)3+/−0.37×10(−)3 cm h-1 (mean +/− s.d., N=30). No evidence was found for a significant contribution of the gills or the nephridia to thiosulphate permeation. Thiosulphate flux followed the concentration gradient, showing a linear correlation (r=0.997) between permeated and supplied (10–100 mmol l-1) thiosulphate. The permeability of thiosulphate was not sensitive to the presence of various metabolic inhibitors, implicating a permeation process independent of membrane proteins and showing that the lugworm does not need to use energy to dispose of the sulphide detoxification product. The present data suggest a passive permeation of thiosulphate across the body wall of A. marina. In live lugworms, thiosulphate levels in the coelomic fluid and body wall tissue decreased slowly and at similar rates during recovery from sulphide exposure. The decline in thiosulphate levels followed a decreasing double-exponential function. Thiosulphate was not further oxidized to sulphite or sulphate but was excreted into the sea water.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Tomás Lombardo ◽  
Guillermo A. Blanco

Clot formation in the sipunculidThemiste petricola, a coelomate nonsegmented marine worm without a circulatory system, is a cellular response that creates a haemostatic mass upon activation with sea water. The mass with sealing properties is brought about by homotypic aggregation of granular leukocytes present in the coelomic fluid that undergo a rapid process of fusion and cell death forming a homogenous clot or mass. The clot structure appears to be stabilized by abundant F-actin that creates a fibrous scaffold retaining cell-derived components. Since preservation of fluid within the coelom is vital for the worm, clotting contributes to rapidly seal the body wall and entrap pathogens upon injury, creating a matrix where wound healing can take place in a second stage. During formation of the clot, microbes or small particles are entrapped. Phagocytosis of self and non-self particles shed from the clot occurs at the clot neighbourhood, demonstrating that clotting is the initial phase of a well-orchestrated dual haemostatic and immune cellular response.


This paper deals with chemical analyses for hydrogen, sodium, potassium, calcium, chloride, sulphate and nitrate ions in daily precipitation samples collected in the English Lake District, and examines the correlations of these analyses with ( a ) one another, ( b ) the amount of precipitation, ( c ) wind direction, ( d ) wind velocity, and ( e ) temperature. Highly significant correlations are found between estimates for H, K, Ca, NO 3 and SO 4 ions, and atmospheric pollution appears to supply much of the sulphate in Lake District rain, since it comes largely as sulphuric acid from the south-east. The correlation between Na and Cl is also extremely close, with the proportion between the two ions very similar to that in sea water. Since these two ions are supplied mainly from the south-west, in amounts which are greatly increased by high winds, sea spray may be inferred as the principal source. Nevertheless, evidence is presented for some small supply from atmospheric pollution, and it is furthermore suggested that mixed droplets of sea salt and sulphuric acid may, upon abstraction of moisture by freezing or evaporation, release gaseous hydrogen chloride to the air and so alter the balance of Na and Cl in precipitation. The supply of Na and Cl is also considerably higher in cold than in warm weather, a phenomenon possibly connected with stormier conditions and greater evaporation over the Atlantic Ocean. The atmospheric contribution of ions to natural waters via precipitation is shown to be of great importance, in particular to bog pools, to upland tarns on hard rocks, and to the soil solution in highly organic mor humus layers overlying heavily leached hillside soils. Sodium and chloride in most surface waters appears to be almost wholly supplied by sea spray, while calcium and magnesium bicarbonates are the main products of soil weathering. A net loss of rain acids is evident in all soil waters, although some may be more acid than normal rain water owing to considerable concentration by evaporation. The soil waters are relatively rich in potassium, presumably supplied from decaying vegetation.


1970 ◽  
Vol 53 (2) ◽  
pp. 425-443
Author(s):  
C. R. FLETCHER

1. Nereis diversicolor tolerates changes in the concentration of calcium and magnesium in its coelomic fluid proportional to the concentrations in the medium between chlorosities of 100-1000 mM/kg of water. 2. In lower salinities both ions are maintained relatively constant providing that the ratios of these ions to chloride in the medium are similar to the ratios in sea water. 3. The ratio of the concentration of calcium in the coelomic fluid to the concentration in the medium is a function of the salinity of the medium but not of the calcium concentration. 4. Both calcium and magnesium are at lower electrochemical potentials in the coelomic fluid than in the medium, indicating that it is not necessary to invoke active uptake. 5. The rate of calcium influx is substantial. 6. In salinities below to mM of chloride/kg of water the urine must contain less calcium than the coelomic fluid. 7. The significance of these results is discussed.


1960 ◽  
Vol s3-101 (54) ◽  
pp. 149-176
Author(s):  
R. B. CLARK ◽  
M. E. CLARK

Nephtys lacks circular body-wall muscles. The chief antagonists of the longitudinal muscles are the dorso-ventral muscles of the intersegmental body-wall. The worm is restrained from widening when either set of muscles contracts by the combined influence of the ligaments, some of the extrinsic parapodial muscles, and possibly, to a limited extent, by the septal muscles. Although the septa are incomplete, they can and do form a barrier to the transmission of coelomic fluid from one segment to the next under certain conditions, particularly during eversion of the proboscis. Swimming is by undulatory movements of the body but the distal part of the parapodia execute a power-stroke produced chiefly by the contraction of the acicular muscles. It is suspected that the extrinsic parapodial muscles, all of which are inserted in the proximal half of the parapodium, serve to anchor the parapodial wall at the insertion of the acicular muscles and help to provide a rigid point of insertion for them. Burrowing is a cyclical process involving the violent eversion of the proboscis which makes a cavity in the sand. The worm is prevented from slipping backwards by the grip the widest segments have on the sides of the burrow. The proboscis is retracted and the worm crawls forward into the cavity it has made. The cycle is then repeated. Nephtys possesses a unique system of elastic ligaments of unusual structure. The anatomy of the system is described. The function of the ligaments appears to be to restrain the body-wall and parapodia from unnecessary and disadvantageous dilatations during changes of body-shape, and to serve as shock-absorbers against the high, transient, fluid pressures in the coelom, which are thought to accompany the impact of the proboscis against the sand when the worm is burrowing. From what is known of its habits, Nephtys is likely to undertake more burrowing than most other polychaetes.


2020 ◽  
Vol 1 (2) ◽  
pp. 97-109
Author(s):  
Fathan Pangestu ◽  
Andri Andri

Palembang City is one of the big cities in Indonesia. Along with the increasing population and the increasing number of motorized vehicles, it will certainly have an impact on the increasing number of traffic accidents in the city of Palembang. In this study, the writer will determine the pattern of traffic accidents by using the fp-growth algorithm and using various variables. The variables that will be used consist of weather, time of incident, road geometry, profession, level of injury. This research is expected to be a reference for the police to be able to take anticipatory measures in order to reduce the number of traffic accidents in the Palembang City area. The fp-growth algorithm can be applied properly to determine the pattern of the causes of traffic accidents in the city of Palembang by using 2 minimum support of 40% and 50% and 2 minimum confidence of 70% and 90%. Based on the resulting rules, there are rules with the highest confidence value of 98% with these rules: When an accident occurs with a Side-Side accident type, the accident occurs in sunny weather conditions


2020 ◽  
pp. 84-87
Author(s):  
S. V. Koroleva ◽  
N. B. Shulyak

Relevance. The most complex and common physiological disease on the cabbage is a tip burn, associated with impaired Ca2 + transport inside the plant. Of all the ways to control this physiological disease, the most effective is the cultivation of tolerant hybrids. Material and methods.The aim of the research was to evaluate the mid-late and late ripening F1 hybrids of white cabbage for a tip burn and to determine the degree of hybrids responsiveness to calcium deficiency depending on weather conditions. The studies were carried out at breeding and experimental plot of the vegetable growing department at All-Russian Rice Research Institute in 2017-2019 on drip irrigation. Material - hybrid combinations of ARRRI breeding.Results. The manifestation of a physiological disturbance called “burn of the top of the inner leaves of the cabbage head” or “tip burn” on individual hybrids was observed during all years of cultivation, but to a different degree; The greatest damage to the heads was recorded in the years (2017 and 2019) with high productivity, which is due to the intensive assimilation ability against the background of warm sunny weather. In 2019, the manifestation of burns was noted in 25% of hybrids, which allowed them to be divided into 4 groups, depending on the degree of damage and the spread of the disease.It was established that hybrids with overmature standing for 2.5-3 weeks and also hybrids that were promptly removed at the time of mass technical ripeness had a high degree of damage. The lines that are most often found in hybrid combinations with signs of burns (269-824, Agr1321, 269Jas13, Byum112, Yas25, etc.) were identified, but it is rather difficult to assume the nature of inheritance, and, therefore, to develop the principle of pair selection when developing relatively stable hybrids also not yet possible.


1953 ◽  
Vol 1 (4) ◽  
pp. 225-244
Author(s):  
C.W.C. Beekom

The effect of sea floods on grassland is described and recommendations are made for the restoration of inundated grassland. Turf may be heavily damaged after +or- 4 weeks inundation with water containing more than 20 g. NaCl per 1. At lower salt concentrations Poa sp. and Trifolium repens are still badly damaged but other species, notably Lolium perenne, Agrostis stolonifera and Alopecurus sp., are capable of immediate regrowth after drainage. If grassland remains submerged during spring, rising temperatures promote active growth of the grasses followed by rapid decay caused by lack of oxygen. L. perenne is especially sensitive to submergence in warm weather. The dominant weed communities which appear on land on which the turf has been destroyed by sea-water are described. Reseeding is recommended as the quickest method of restoring badly damaged turf. The flooded land should first be thoroughly drained and then repeatedly harrowed to produce a shallow seed-bed on which herbage mixtures can be sown without the application of gypsum. Given average weather conditions, normal permanent grassland mixtures can be sown at salt concentrations, measured in spring, of up to 8-10 g. NaCl per 1. of moisture in the 5-20 cm. soil layer. At a salt concentration of about 10 g. per 1. measured in spring, L. perenne tends to dominate over other species while Poa sp. and T. repens suffer during the summer. At a salt concentration of 10-15 g. per 1. in spring, Poa sp. and T. repens should be omitted from seed mixtures, instead mixtures consisting of different types of L. perenne, Festuca pratensis and Phleum pratense should be sown. When the salt concentration of the soil moisture is higher that 15 g. per 1. in spring, sowing should be delayed and the weeds checked by mowing or grazing. Temporary rises of the salt concentration in dry symmers to 25 g. per 1. are tolerated by L. perenne, F. pratensis and Ph. pratense; similar rises up to 15-18 g. per 1. are tolerated by Poa sp. and T. repens.-W.J.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1972 ◽  
Vol 57 (1) ◽  
pp. 83-102
Author(s):  
H. J. FYHN ◽  
J. A. PETERSEN ◽  
K. JOHANSEN

1. Physiological responses to environmental stresses of the intertidal cirriped Pollicipes polymerus have been studied by combined field and laboratory experiments. 2. The body temperature of air-exposed animals is always lower than expected from the heat load. Evaporation from the peduncle is responsible for the heat loss. 3. The rate of water loss by evaporation from the peduncle cuticle is 1.5 µl/cm2 h mmHg both at 21 and 27 °C. The transpiration is proportional to the saturation deficit of the air. The water loss from the capitulum is negligible in comparison to that from the peduncle. 4. The haemolymph osmolality of animals in the field increases during exposure to sunshine and decreases during exposure to rain. The increase in haemolymph osmolality during desiccation is equal to that calculated from the decrease in body water. The water loss during air exposure is adequately replaced during submersion, probably by osmosis. 5. Pollicipes is an osmoconformer but is 5-20 m-osmoles hyperosmotic. It tolerates sea-water dilutions down to about 50%. The hyperosmolality seems to be balanced by a high internal hydrostatic pressure. 6. An excretory activity is observed. The excretion is isosmotic to the haemolymph and is possibly an ultrafiltrate of the latter. 7. The muscle cells show volume regulation, but free amino acids seem to be unimportant in regulation of intracellular osmolality. The concentration of ninhydrinpositive substances in the muscle tissue is about 200 mM for animals in full strength sea water.


1976 ◽  
Vol 65 (1) ◽  
pp. 131-145 ◽  
Author(s):  
E. D. Stevens ◽  
A. M. Sutterlin

1. The ability of fish gills to transfer heat was measured by applying a heat pulse to blood in the ventral aorta and measuring it before and after passing through the gills of a teleost, Hemitripterus americanus. 2. 80–90% of heat contained in the blood is lost during passage through the gills. 3. The fraction of heat not lost during passage through the gills is due to direct transfer of heat between the afferent and efferent artery within the gill bar. 4. The major fraction of metabolic heat (70 - 90%) is lost through the body wall and fins of the sea raven in sea water at 5 degrees C; the remainder is lost through the gills.


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