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1.
Time of day and water temperature modify the physiological stress response in green sturgeon,Acipenser medirostris 总被引:4,自引:0,他引:4
Lankford SE Adams TE Cech JJ 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,135(2):291-302
The effects of time of day and water temperature on the acute physiological stress response were investigated in young-of-the-year green sturgeon (Acipenser medirostris). The response to a 1-min air-emersion stressor was assessed during the day (08.00 h) and at night (20.00 h), as well as after acclimation to either 11 degrees C or 19 degrees C. Blood samples were collected prior to stress and at several times after exposure to the stressor, and plasma concentrations of cortisol, lactate, and glucose were determined. The magnitudes of cortisol (19.1 ng ml(-1) vs. 4.9 ng ml(-1)) and lactate (190.6 mg l(-1) vs. 166.7 mg l(-1)) were significantly higher in fish stressed at night when compared with the day. There were no significant differences in glucose levels between time periods. Although, acclimation temperature did not affect peak cortisol concentrations (56.7 and 50.3 ng ml(-1) at 11 degrees C and 19 degrees C, respectively), the duration of the response was significantly extended at 11 degrees C. Post-stressor lactate increases were similar between temperature groups, but at 11 degrees C post-stressor glucose levels were significantly increased through 6 h, suggesting stressor-induced glycogenolysis and gluconeogenesis or decreased glucose utilization. These data demonstrate that the physiological stress response in green sturgeon is modified by both time of day and temperature. 相似文献
2.
To detect shifts in the threshold core temperature (Tc) for sweating caused by particular nonthermal stresses, it is necessary to stabilize or standardize all other environmental and physiological variables which cause such shifts. It is, however, difficult to cause progressive changes in Tc without also causing changes in skin temperature (Tsk). This study compares the technique of body warming by immersion in water at 40 degrees C, and subsequent body cooling in water at 28 degrees C, to determine the core threshold for sweating, with one by which Tc was raised by cycling exercise in air at 20 degrees C, and then lowered by immersion in water at 28 degrees C. The first of these procedures involved considerable shifts in Tsk upon immersion in water at 40 degrees C, and again upon transfer to water at 28 degrees C; the second procedure caused only small changes in Tsk. The onset of sweating at a lower esophageal temperature (Tes) during immersion in water at 40 degrees C (36.9 +/- 0.1 degrees C) than during exercise (37.4 +/- 0.3 degree C) is attributed to the high Tsk since Tes was then unchanged. Likewise, the rapid decline in the sweat rate during immersion at 28 degrees C had the same time course to extinction after the pretreatments. This related more to the Tsk, which was common, than to the levels or rates of change of Tes, which both differed between techniques. Tes fell most rapidly, and thus sweating was extinguished at a lower Tes, following 40 degrees C immersion than following exercise.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Bonvillain CP Rutherford DA Kelso WE Green CC 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2012,163(1):15-21
The crayfish industry in Louisiana is the largest in the United States, with crayfish frequently harvested from waters that experience episodic or chronic hypoxia (dissolved oxygen [DO]≤ 2 mg/l). We examined physiological biomarkers (hemolymph lactate, glucose, and protein concentrations) of hypoxic stress in the red swamp crayfish Procambarus clarkii from chronically hypoxic natural habitats and laboratory hypoxia experiments. P. clarkii from normoxic and hypoxic areas in the Atchafalaya River Basin were sampled monthly from April to July 2010. Laboratory experiments subjected P. clarkii to severe hypoxia (1 mg/l DO), moderate hypoxia (2 mg/l DO), or normoxic conditions (control: DO>7.5 mg/l) for 12, 24, and 48 h. P. clarkii from normoxic and hypoxic natural habitats did not display significantly different hemolymph lactate or glucose concentrations; however, mean hemolymph protein concentration was significantly lower in crayfish from hypoxic areas. P. clarkii exposed to severe hypoxia in laboratory experiments had significantly higher hemolymph lactate and glucose concentrations for all three exposure times, whereas large differences in protein concentrations were not observed. These results suggest that elevated hemolymph lactate and glucose concentrations are responses to acute hypoxia in P. clarkii, while differences in protein concentrations are the result of chronic hypoxic exposure. 相似文献
4.
In a series of laboratory studies designed to simulate bycatch processes, sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium oncentrations. In fish that were towed in a net and exposed to air, cortisol, lactate, potassium and sodium concentrations increased, but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air, that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood. 相似文献
5.
Racotta IS Hernández-Herrera R 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2000,125(4):437-443
Juvenile shrimp were individually exposed during 24 h to 0.007 (control), 0.36, 1.07, and 2.14 mmol/l total ammonia-N at 28 degrees C and 39 ppt salinity. After 22 h of ammonia-N exposure, oxygen consumption was measured for 2 h, and then hemolymph, hepatopancreas, and muscle tissues were sampled. Oxygen consumption, and levels of lactate and glycogen in the hepatopancreas increased significantly at the highest ammonia-N concentration. Concentration of oxyhemocyanin, acylglycerol, and cholesterol in hemolymph, and lactate in muscle decreased significantly in the group exposed to the highest ammonia levels. The changes observed in hemolymph and tissue metabolic fuels suggest a reduced use of carbohydrate through anaerobic metabolism and an increase in the use of lipids to satisfy the metabolic demand. 相似文献
6.
The impact of variation in water temperature and dissolved oxygen on recovery of largemouth bass Micropterus salmoides from exercise was examined. For this, largemouth bass were first exercised and recovered for either 1, 2 or 4 h at ambient water temperatures (25° C) in fully oxygenated water. Results showed that exercise forced fish to utilize anaerobic metabolism to meet energy demands, and resulted in reductions in anaerobic energy stores adenosine triphosphate (ATP), Phosphocreatine (PCr) and glycogen. Exercise also resulted in a seven‐fold increase in lactate within white muscle. After 2 h of recovery in oxygenated water at acclimation temperature, physiological recovery from exercise was under way, and by 4 h most variables examined had returned to control levels. Next, largemouth bass were exercised at ambient temperatures and recovered for 2 h in environments with either elevated temperature (32° C), reduced temperature (14 and 20° C), hypoxia or hyperoxia. Both elevated and reduced temperature impaired recovery of tissue lactate and tissue ATP relative to fish recovered in water at acclimation temperature, while hyperoxic water impaired recovery of tissue ATP. Moderately hypoxic waters impaired the recovery of plasma glucose, plasma lactate and tissue PCr relative to fish recovered in fully oxygenated water. Results from this study are discussed in the context of critical oxygen and temperature guidelines for largemouth bass. In addition, several recommendations are made concerning remedial treatments used in livewells (tanks) during angling tournaments when fish are recovering from exercise associated with angling. 相似文献
7.
Folco Giomi Saša Raicevich Otello Giovanardi Fabio Pranovi Paolo Di Muro Mariano Beltramini 《Hydrobiologia》2008,606(1):195-202
Several studies have considered the direct and indirect effects of demersal trawling on discarded species in terms of sublethal
damages, survival, and stress due to the fishing processes. Nevertheless the effects of air temperature on the physiological
stress and the survival of species during sorting operations were only marginally explored. This factor could be particularly
important in the context of sustainable fisheries at temperate latitudes where the seasonal variation of air temperature can
be particularly pronounced. In this study the seasonal effects of rapido trawling on the non-target species Liocarcinus depurator (Portunidae) in the Northern Adriatic Sea (Mediterranean Sea) have been compared by applying survival tests and considering
the unbalance in metabolites’ concentration as indicators of physiological stress. Results showed consistently higher mortalities
during exposure to air in summer (temperature: 28°C), which reached about 96% in 20 min, compared to winter (temperature:
9°C) when only 2% of individuals died. Furthermore trawled and emersed crabs showed significant increase of hemolymph ammonia,
lactate, and glucose concentrations as effects of extreme exercise and suffocation, which was more prominent during summer,
suggesting that air temperature can play an important role in determining non-target species survival.
Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan
Challenges to Marine Ecosystems 相似文献
8.
D G Penney C C Helfman J C Dunbar L E McCoy 《Canadian journal of physiology and pharmacology》1991,69(8):1168-1177
Human and animal studies suggest a poorer outcome in the presence of abnormal blood glucose concentration during cerebral hypoxia-ischemia. It is unknown whether this is also the case in acute severe carbon monoxide poisoning. Using Levine-prepared rats, three groups were established and exposed to CO to answer this question: (1) hyperglycemics resulting from the administration of a 50% glucose solution, (2) hypoglycemics resulting from the administration of normal saline, and (3) untreated controls. The rats inhaled 2400 ppm CO for 90 min in the absence of anesthesia. Blood glucose was raised to a mean value of 402 mg/dL just prior to CO exposure in group 1. This resulted in an increased mortality rate (i.e., 54%), and during 4 h of room air recovery an impaired ability to regain body temperature, an increased plasma lactate dehydrogenase activity, and an increased neurologic deficit as compared with group 3. Hypoglycemia, which developed during CO exposure in group 2 (mean minimum glucose after 90 min, 44 mg/dL), resulted in an increased mortality rate (i.e., 46%), and during 4 h of room air recovery an impaired ability to regain body temperature and an increased neurologic deficit as compared with group 3. Blood glucose concentration in the rats in groups 2 and 3 that died during or shortly after CO exposure was significantly depressed relative to the survivors of those groups. Plasma insulin activity was elevated during CO exposure in group 1 as compared with group 3, but fell during recovery; insulin remained low throughout CO exposure and recovery in group 2. The results demonstrate the deleterious effects of both a very high and a very low blood glucose concentration during acute CO exposure. 相似文献
9.
Oliveira GT Eichler P Rossi IC Da Silva RS 《Journal of experimental zoology. Part A, Comparative experimental biology》2004,301(3):240-248
C. granulata is a semiterrestrial crab that lives in the mesolittoral and the supralittoral zones of estuaries and faces hypoxia and anoxia when exposed to atmospheric air. The carbohydrate or protein content of the diets administered to the crabs induced different metabolic adjustments during anoxia and post-anoxia recovery period. During the first hour in anoxia a marked increase in L-lactate concentration in hemolymph was induced, followed by a reduction in its levels accompanied by two peaks in hepatopancreas gluconeogenic capacity. Anoxia exposure did not induce a reduction in the hepatopancreas phosphoenolpyruvate carboxykinase activity in either dietary group. Our results suggest that in anaerobiosis this crab uses the conversion of lactate to glucose in hepatopancreas to maintain the acid-base balance and the glucose supply. In post-anoxia recovery, the fate of L-lactate is the hepatopancreas gluconeogenesis in high protein maintained crabs. On the other hand, in the crabs maintained on carbohydrate-rich diet the L-lactate levels decreased gradually in the hemolymph during the post-anoxia recovery; however, the hepatopancreas gluconeogenesis did not increase. In both dietary groups, an increase in the gluconeogenic capacity of hepatopancreas occurred at 30 h of post-anoxia recovery. 相似文献
10.
This study was intended to discover whether forcing largemouth bass (Micropterus salmoides) to swim at 0.5 body lengths/second following exercise would expedite recovery relative to fish recovered in static water. Exercise resulted in a suite of physiological disturbances for largemouth bass that included a depletion of anaerobic energy stores, an accumulation of lactate, and increased cardiac output. At 1 h following exercise, exhaustively exercised largemouth bass forced to swim exhibited expedited recovery relative to fish in static water, evidenced by lower concentrations of lactate in white muscle, elevated concentrations of phosphocreatine in white muscle, and reduced concentrations of glucose in plasma. By 4 h postexercise, largemouth bass forced to swim during recovery exhibited signs of physiological disturbance that were absent in fish recovered in static water. These signs of disturbance included a loss of osmotically active particles from plasma, elevated lactate in plasma, reductions of phospocreatine in white muscle, and increased cardiac output. These results are discussed in relation to the body of work with salmonid fishes showing physiological benefits to recovering fish in flowing water. 相似文献
11.
Nine healthy volunteers underwent three experimental procedures in random order. The protocols were 4 h of thermal dehydration followed by 2 h of head-out water immersion, 4 h of thermal dehydration followed by 2 h of chair rest, and 6 h of rest in the supine position. Four hours of heat exposure (50 degrees C) resulted in a body weight loss of approximately 3.5%. Plasma osmolality rose by approximately 5 mosmol/kg, mean arterial pressure (MAP) decreased from 85 to 78 mmHg, and body temperature increased from 36.8 to 38.6 degrees C. As a consequence of the combined action of hypertonicity, hypovolemia, hypotension, and hyperthermia, plasma arginine vasopressin (AVP) increased from 2.1 to 8.1 pg/ml after 4 h thermal dehydration. Changes in body weight, plasma osmolality, body temperature, and MAP were similar after either a subsequent 2 h of water immersion or 2 h of chair rest. However, during chair rest plasma AVP remained elevated (8.4 pg/ml), whereas during immersion plasma AVP decreased from 8.1 to 4.7 pg/ml. This was probably due to the central hypervolemia induced by immersion. Our results support the hypothesis that central hypervolemia rather than hypotonicity is the primary stimulus for AVP suppression during water immersion in dehydrated subjects. During the early immersion period hypoosmolality might contribute to the AVP suppression. 相似文献
12.
This research examined the influence of acute changes of water temperature on the recovery processes following exhaustive exercise in juvenile Atlantic salmon (Salmo salar). White muscle phosphocreatine (PCr), ATP, lactate, glycogen, glucose, pyruvate, plasma lactate, and plasma osmolality were measured during rest and at 0, 1, 2, and 4 h following exhaustive exercise in fish acclimated and exercised at 12 degrees C and acutely exposed to either 6 degrees C or 18 degrees C water during recovery. An acute exposure to 6 degrees C water during the recovery period resulted in a severe reduction of metabolic recovery in salmon. However, metabolites such as muscle PCr and ATP and plasma lactate recovered very quickly (2-4 h) in fish acutely exposed to 18 degrees C during recovery. Overall, differences exist when postexercise metabolite levels are compared between acclimated fish and those fish acutely exposed to different water temperatures (either higher or lower). Taken together, the findings of the acute experiments suggest that at some point following exercise fish may seek warmer environments to speed the recovery process. However, the relationship between behavioural thermoregulation and recovery following exhaustive exercise in fish is not well understood. 相似文献
13.
Mautz WJ Dohm MR 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2004,139(3):371-377
Ozone at concentrations found in urban air pollution is known to have significant physiological effects on humans and other mammals. Exposure of the lizard, Sceloporus occidentalis, to 0.6 ppm ozone for 4 h at 25 degrees C induced 1.6 degrees C of behavioral hypothermia immediately following exposure, but selected body temperature recovered to control 35.3 degrees C the next day. Lizards exposed at 35 degrees C to 0.6 ppm ozone for 4 h selected body temperatures 1.9 degrees C below controls after exposure, and the behavioral hypothermic response persisted and increased to 3.3 degrees C the following day. Four-hour exposures of the frog, Pseudacris cadaverina, to 0.2 to 0.8 ppm ozone resulted in concentration-dependent alterations of respiration including depression of lung ventilation and oxygen consumption and the adoption of a low profile posture that reduced the exposed body surface. Ozone levels in wilderness habitats downwind of urban sources can potentially have stressful physiological effects on wildlife. Defensive physiological and behavioral reactions to ozone exposure may interfere with routine activities, and oxidant air pollution may be in part responsible for observed wildlife population declines. 相似文献
14.
Payette AL McGaw IJ 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,136(3):539-556
The behavioral thermoregulation of the red swamp crayfish, Procambarus clarki, was investigated in its burrow environment. In the field, air and water temperatures within crayfish burrows fluctuated less compared with surface temperatures in the Mojave Desert. However, crayfish could still experience sub-optimal temperature regimes inside burrows. In the laboratory, P. clarki heated and cooled more rapidly in water than in air. In a thermal gradient, the crayfish selected a water temperature of 22 degrees C and avoided water temperatures above 31 degrees C and below 12 degrees C. Observations of behavior in an artificial burrow showed that P. clarki displayed three main shuttling behaviors between water and air in response to temperature. The number of bilateral emersions and emigrations, as well as the amount of time spent in air (in a 24 h period), were significantly greater at 34 degrees C than at 12, 16, 22 or 28 degrees C. This reflected an increased use of the behavioral thermoregulation at temperatures approaching the critical thermal maximum of this species. Upon migrating from 34 degrees C water into 38 degrees C air, crayfish body temperature decreased significantly. These periods of emersion were interspersed with frequent dipping in the water, allowing the crayfish to gain the benefits of evaporative cooling, without the physiological costs incurred by long-term exposure to air. 相似文献
15.
American oysters, Crassostrea virginica, and hard clams, Mercenaria mercenaria, were experimentally contaminated with Escherichia coli, Salmonella typhimurium, and Shigella flexneri either by intracardial injection or via the natural route of ingestion. Bacterial inactivation in the hemolymph was monitored for 72 h after exposure to these enteric pathogens at 20 and 6 degrees C. At 6 degrees C, both mean bacterial uptake by ingestion and subsequent clearance was singificantly lower that at 20 degrees C. However, substantial bacterial clearance from the hemolymph occurred for both shellfish at each temperature. At 20 degrees C, viable bacteria were no longer detectable after 24 h in hemolymph of either clams or oysters after exposure to contaminated water containing 4 x 10(3) bacteria per ml. 相似文献
16.
Vivo clearance of enteric bacteria from the hemolymph of the hard clam and the American oyster. 总被引:1,自引:1,他引:0
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American oysters, Crassostrea virginica, and hard clams, Mercenaria mercenaria, were experimentally contaminated with Escherichia coli, Salmonella typhimurium, and Shigella flexneri either by intracardial injection or via the natural route of ingestion. Bacterial inactivation in the hemolymph was monitored for 72 h after exposure to these enteric pathogens at 20 and 6 degrees C. At 6 degrees C, both mean bacterial uptake by ingestion and subsequent clearance was singificantly lower that at 20 degrees C. However, substantial bacterial clearance from the hemolymph occurred for both shellfish at each temperature. At 20 degrees C, viable bacteria were no longer detectable after 24 h in hemolymph of either clams or oysters after exposure to contaminated water containing 4 x 10(3) bacteria per ml. 相似文献
17.
Peter Tikuisis 《Journal of applied physiology》2003,95(1):89-96
Certain previous studies suggest, as hypothesized herein, that heat balance (i.e., when heat loss is matched by heat production) is attained before stabilization of body temperatures during cold exposure. This phenomenon is explained through a theoretical analysis of heat distribution in the body applied to an experiment involving cold water immersion. Six healthy and fit men (mean +/- SD of age = 37.5 +/- 6.5 yr, height = 1.79 +/- 0.07 m, mass = 81.8 +/- 9.5 kg, body fat = 17.3 +/- 4.2%, maximal O2 uptake = 46.9 +/- 5.5 l/min) were immersed in water ranging from 16.4 to 24.1 degrees C for up to 10 h. Core temperature (Tco) underwent an insignificant transient rise during the first hour of immersion, then declined steadily for several hours, although no subject's Tco reached 35 degrees C. Despite the continued decrease in Tco, shivering had reached a steady state of approximately 2 x resting metabolism. Heat debt peaked at 932 +/- 334 kJ after 2 h of immersion, indicating the attainment of heat balance, but unexpectedly proceeded to decline at approximately 48 kJ/h, indicating a recovery of mean body temperature. These observations were rationalized by introducing a third compartment of the body, comprising fat, connective tissue, muscle, and bone, between the core (viscera and vessels) and skin. Temperature change in this "mid region" can account for the incongruity between the body's heat debt and the changes in only the core and skin temperatures. The mid region temperature decreased by 3.7 +/- 1.1 degrees C at maximal heat debt and increased slowly thereafter. The reversal in heat debt might help explain why shivering drive failed to respond to a continued decrease in Tco, as shivering drive might be modulated by changes in body heat content. 相似文献
18.
This study examined the effects of an oral 30-mg dose of pyridostigmine bromide (PYR) on thermoregulatory and physiological responses of men undergoing cold stress. Six men were immersed in cold water (20 degrees C) for up to 180 min on two occasions, once each 2 h after ingestion of PYR and 2 h after ingestion of a placebo. With PRY, erythrocyte cholinesterase inhibition was 33 +/- 12% (SD) 110 min postingestion (10 min preimmersion) and 30 +/- 7% at termination of exposure (mean 117 min). Percent cholinesterase inhibition was significantly related to lean body mass (r = -0.91, P less than 0.01). Abdominal discomfort caused termination in three of six PYR experiments but in none of the control experiments (mean exposure time 142 min). During immersion, metabolic rate, ventilatory volume, and respiratory rate increased significantly (P less than 0.05) over preimmersion levels and metabolic rate increased with duration of immersion (P less than 0.01) in both treatment but did not differ between conditions. PYR had no significant effect on rectal temperature, mean body temperature, thermal sensations, heart rate, plasma cortisol, or change in plasma volume. It was concluded that a 30-mg dose of PYR does not increase an individual's susceptibility to hypothermia during cold water immersion; however, in combination with cold stress, PYR may result in marked abdominal cramping and limit cold tolerance. 相似文献
19.
Fernando Díaz Ana Denisse Re Ariadna Sánchez Honorio Cruz Ricardo A. González L. Noemi Sánchez 《Marine and Freshwater Behaviour and Physiology》2013,45(6):365-374
Exposure to thermal stress was shown to have a significant effect on the osmotic pressure of the hemolymph, glucose levels, total count of hemocyte (TCH), and proPO activity in adult white shrimp Litopenaeus vannamei. Exposure of the shrimp to CTMax significantly increased the osmotic pressure of the hemolymph relative to the control group. In organisms reaching CTMax, temperature elicited a secondary stress response that included an increase in hemolymph glucose of 31?mg?mL?1. Metabolites in hemolymph such as cholesterol, acylglycerides, and total protein were not significantly affected by exposure to CTMax. CTMax exposure affected several immunological parameters causing decreases in TCH and proPO activity. We suggested that biomarkers such as osmolality, glucose levels, TCH, and proPO activity could be used as sensitive predictors of exposure to CTMax in white shrimp. 相似文献
20.
Elisabeth Simonik 《Marine and Freshwater Behaviour and Physiology》2014,47(2):101-115
The green shore crab, Carcinus maenas, undergoes on average 6?h periods of emersion during each low-tide cycle during the summer months. Under those conditions, the crab is cut off from its normal water environment and is exposed to potential stress from a suite of environmental and physiological changes: dehydration, compromised gas exchange and resultant internal hypoxia and hypercapnia, thermal stress, and ammonia toxicity. This study examined the comprehensive responses of the green crab in water and to a 6?h emersion period laboratory simulation of a tidal cycle followed by a 1?h re-immersion period, measuring indicators of dehydration, hemolymph osmolality, oxygen uptake, hemolymph acid–base status, heart and ventilatory rate, and hemolymph ammonia and ammonia excretion. Green crabs showed physiological responses of varying magnitude to 6?h of emersion. Individuals were found in the field exclusively under rocks and large clumps of seaweed where temperatures were approximately half those of exposed surfaces and relative humidity was about twice as high as ambient air. During emersion, crabs lost less than 5% of their wet weight, and hemolymph osmolality did not increase significantly. Oxygen uptake continued in air at about 50% of the control, aquatic values; and the gills continued to be ventilated by the scaphognathite, albeit at lower rates. Hemolymph lactate concentrations increased, indicating a shift to a greater reliance on anaerobic metabolism to support energetic needs. A slight acidosis developed in the hemolymph after 1?h of emersion, but it did not increase thereafter. Ammonia concentrations in the hemolymph were unchanged, as ammonia was volatilized by the gills and excreted into the air as NH3 gas. These results show that the green crab copes with emersion by seeking refuge in microhabitats that mitigate the changes in the physical parameters of intertidal emersion. Physiologically, desiccation is avoided, cardio-respiratory processes are maintained at reduced levels, and hemolymph acid–base balance is minimally affected. Ammonia toxicity appears to be avoided by a shift to excreting NH3 gas directly or indirectly to air. 相似文献