Water relations of pliable-shelled eggs of common snapping turtles (Chelydra serpentina)

1980 ◽  
Vol 58 (8) ◽  
pp. 1404-1411 ◽  
Author(s):  
Gary C. Packard ◽  
Theodore L. Taigen ◽  
Mary J. Packard ◽  
Thomas J. Boardman
Keyword(s):  
Water Vapour ◽  
Water Relations ◽  
Liquid Water ◽  
Water Loss ◽  
Considerable Importance ◽  
Chelydra Serpentina ◽  
Snapping Turtles ◽  
Transpirational Water Loss

Pliable-shelled eggs of common snapping turtles were incubated at 29 °C under hydric conditions simulating those to which eggs are exposed in natural nests. Eggs exposed to conditions similar to those encountered at the centre of nests experienced net declines in mass during incubation, presumably owing to the loss of water vapour to air trapped inside the chamber. Eggs exposed to conditions similar to those encountered at the periphery of nests absorbed liquid water across that part of their shell contacting the substrate and increased in mass during the early weeks of incubation. However, transpirational water loss from exposed surfaces of these eggs seemed to increase coincident with metabolism of developing embryos, and became high enough by the midpoint of incubation that absorption of liquid water could not compensate for the loss of water vapour, thereby causing eggs to decline in mass for the remainder of incubation. The size of hatchlings was related both to the position of eggs inside the chamber and to wetness of the substrate, indicating that the water exchanges of pliable-shelled eggs of snapping turtles may be of considerable importance to developing embryos.

Daily and seasonal variation in hydric conditions and temperature inside nests of common snapping turtles (Chelydra serpentina)

1985 ◽  
Vol 63 (10) ◽  
pp. 2422-2429 ◽  
Author(s):  
Gary C. Packard ◽  
Gary L. Paukstis ◽  
Thomas J. Boardman ◽  
William H. N. Gutzke
Keyword(s):  
Seasonal Variation ◽  
Water Potential ◽  
Water Relations ◽  
Chelydra Serpentina ◽  
Fair Weather ◽  
Diel Cycles ◽  
Water Potentials ◽  
Snapping Turtles ◽  
Warm Weather ◽  
Heavy Rainfalls

Water potential and temperature are interrelated variables that must be studied simultaneously to gain insight concerning the water relations of reptilian eggs incubating in subterranean nests. We measured these variables inside nests of common snapping turtles (Chelydra serpentina) using thermocouple psychrometry. Water potentials in nests were high after heavy rainfalls, but declined during periods of fair weather. Likewise, temperatures in nests increased progressively during intervals of warm weather, but declined abruptly during cool periods accompanied by overcast and precipitation. On clear days, diel cycles in temperature occurred at the top, in the middle, and at the bottom of nests, but the cycles were slightly out of phase and their amplitudes decreased with increasing depth. These cycles in temperature drove cycles in evaporation–condensation of water that led in turn to complex cycles in diffusion of vapour. Net movement of vapour was into nests on some occasions, but out of them on others. Transport of liquid occurred also in the vicinity of nests, but probably was less important than transport of vapour as a means for translocating water. The eggs themselves influenced water potentials and vapour pressures in the vicinity of their nests and thereby elicited different movements of water in their immediate surroundings than occurred in the soil at large.

The Adaptive Strategy for Overwintering by Hatchling Snapping Turtles (Chelydra serpentina)

2001 ◽  
Vol 35 (3) ◽  
pp. 514 ◽  
Author(s):  
Paul A. Sims ◽  
Gary C. Packard ◽  
Philip L. Chapman
Keyword(s):  
Adaptive Strategy ◽  
Chelydra Serpentina ◽  
Snapping Turtles

Mercury concentrations in snapping turtles (Chelydra serpentina) correlate with environmental and landscape characteristics

Ecotoxicology ◽  
2011 ◽  
Vol 20 (7) ◽  
pp. 1599-1608 ◽  
Author(s):  
Madeline A. Turnquist ◽  
Charles T. Driscoll ◽  
Kimberly L. Schulz ◽  
Martin A. Schlaepfer
Keyword(s):  
Chelydra Serpentina ◽  
Landscape Characteristics ◽  
Snapping Turtles

A Simplified Thermodynamic Analysis of a LiBr-H2O Vertical Tube Absorber

2002 ◽  
Author(s):  
E. D. Rogdakis ◽  
V. D. Papaefthimiou
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water Vapour ◽  
Liquid Water ◽  
Mass Fraction ◽  
Superheated Steam ◽  
Vertical Tube ◽  
Solution Temperature ◽  
Absorption Process

One of the most important components of an absorption air-conditioning/heat pump system is the absorber, where the refrigerant water vapour is absorbed into the liquid solution. While absorption systems have been in use for several years, the complex transport phenomena occurring in the absorber are not fully elucidated yet. Thus, an attempt is made to model the absorption process of water vapour in aqueous solutions of lithium bromide considering a falling-film, vertical-tube absorber. The proposed analysis is based on the formulation of four differential equations describing the spatial variation (parallel to the tube-axis) of solution mass, temperature, mass fraction and coolant temperature. The system of ordinary differential equations is numerically solved using a non-stiff numerical method. Thermophysical properties and especially, heat and mass transfer coefficients are calculated using widely-accepted and reliable relationships, which are extracted from the literature using recently published information on wavy-laminar flows. In the present study, the questionable assumption of treating the water vapour as an ideal gas is heavily modified utilizing. Consequently, the hypothesis of saturated water vapour at the steam-solution interaction surface is revised by introducing an energy difference between the superheated steam and the liquid water within the binary solution. The last correction encouraged us to compare theoretical results for solution temperature, mass fraction and mass flow rate, which were obtained using both assumptions. It was proved that the initial treatment causes an underestimation of the absorbed steam mass and correspondingly, an underestimation of solution temperature and mass fraction at the mass exchange interface. An attempt is made also to identify the effect of mass transfer coefficient on the effectiveness of the absorption process and on the energy differences between the superheated steam and the liquid water either as pure substance or as component of the binary mixture. It was shown that the increase of mass transfer coefficient leads to an increase of steam mass transfer rate and to a corresponding decrease of solution temperature slope at the entrance of a tube. Correspondingly, the increase of mass transfer coefficient results in an increase of heat of absorption and heat of dilution at the same variation range of the solution mass fraction.

Effects of a sudden increase in natural mortality of adults on a population of the common snapping turtle (Chelydra serpentina)

1991 ◽  
Vol 69 (5) ◽  
pp. 1314-1320 ◽  
Author(s):  
Ronald J. Brooks ◽  
Gregory P. Brown ◽  
David A. Galbraith
Keyword(s):  
Clutch Size ◽  
Research Area ◽  
Effective Density ◽  
Egg Mass ◽  
Sudden Increase ◽  
Chelydra Serpentina ◽  
Density Dependent ◽  
Snapping Turtles ◽  
The Mean ◽  
Clutch Mass

A northern population of snapping turtles (Chelydra serpentina) centred around Lake Sasajewun in the Wildlife Research Area in Algonquin Park, Ontario, has been studied and individually marked since 1972. From 1972 to 1985, annual mortality and survivorship of adult females had been estimated at 1 and 96.6%, respectively, and only six dead turtles were found. Lake Sasajewun's population of C. serpentina was estimated in 1978–1979 and 1984–1985 at 38 and 47 adults, respectively. From 1976 to 1987, total number of nests found in the study area remained fairly constant and there were no significant changes in mean clutch size, mean clutch mass, or mean egg mass. On the main nest site, recruitment from 1976 to 1987 was 1.15 (1.8%) new females per year. From 1987 to 1989, we found 34 dead adult snapping turtles in the Wildlife Research Area. Observations of freshly dead animals indicated that most were killed by otters (Lutra canadensis) during the turtles' winter hibernation. A few uninjured turtles also died of septicemia in early spring shortly after emerging from hibernation. The estimated number of adults in Lake Sasajewun was 31 in 1988–1989, and the minimum number of adult residents known to be alive in the lake dropped from 47 in 1986 to 16 in 1989. In 1986 and 1987, annual adult female survivorship was estimated at 80 and 55%, respectively, and estimated numbers of nesting females declined from 82 in 1986 to 71 and 55 in 1987 and 1988, respectively. The actual number of nests found declined by 38 and 20% over the same periods. Although no significant differences occurred in mean egg mass or mean clutch size between 1987 and 1989 and earlier years, the mean clutch mass in 1988 was larger than in 1977 or 1978. This difference appeared to be due to a gradual increase in the mean age and body size of breeding females rather than to density-dependent changes. Recruitment into the adult breeding female population in 1987–1989 remained less than two individuals per year. Hatchling survival and number of juveniles were low throughout the study. Our observations support the view that populations of species with high, stochastic juvenile mortality and long adult life spans may be decimated quickly by increased mortality of adult animals, particularly if numbers of juveniles and immigrants are low. Recovery of such populations should be very slow because of a lack of effective density-dependent response in reproduction and recruitment.

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