Northern Water Research Articles

Multiple paternity in a wild population of northern water snakes, Nerodia sipedon

For most animal species, a single mating is sufficient to fertilize all of a female's offspring. As a result, females do not usually increase their reproductive success with successive matings. However, multiple paternity has been discovered in many animal taxa. We demonstrate that the majority of female water snakes in a wild population mate with more than one male for each litter. Field observations indicated that a highly skewed operational sex ratio (3.6:1 M : F) during the breeding season, while not necessary for multiple paternity to occur, created ample opportunity for females to mate multiply. Protein electrophoretic analysis showed that at least 12 of 14 litters from naturally mated females had more than one father. Since male snakes can not force copulations, multiple matings seem likely to be the result of female choice.

The role of temperature in microhabitat selection by northern water snakes (Nerodia sipedon)

Using field observations and laboratory experiments we examined the role of temperature in microhabitat selection by an eastern Ontario population of northern water snakes (Nerodia sipedon). From 1349 random transects through a marsh we found that basking activity peaked at 09:00 and then declined steadily until 14:00 before increasing again. Our ability to detect snakes depended upon the microhabitat they occupied, and to the time of day when the snakes were encountered in water. In the field, temperatures of basking snakes averaged (±SE) 26.3 ± 0.7 °C (n = 36), while captive snakes in a thermal gradient showed a narrower selectivity, averaging 27.7 ± 0.4 °C (n = 21). The temperatures of basking snakes never exceeded 33 °C, even though a model snake placed in the sun reached 48 °C, suggesting that the snakes were thermoregulating to prevent overheating. In both the field and enclosures, water snakes basked more frequently as the temperature of the air increased relative to the water. Experimental manipulation of water temperature relative to air temperature revealed that temperature influenced microhabitat selection independently of circadian patterns. Finally, when in water, snakes tended to frequent habitats where leopard frogs (Rana pipiens), a common prey species, were most abundant, suggesting that prey distribution may also be an important component of water snake habitat selection.

Thermal constraints on swimming performance and escape response of northern water snakes (Nerodia sipedon)

We examined the influence of body temperature on swimming speed of northern water snakes (Nerodia sipedon) and determined how variation in water temperature influenced their escape response. In a laboratory experiment, swimming speed increased as a function of water temperature and body size. Swimming speed was less thermally dependent at temperatures approximating the snakes' normal range of activity, suggesting that selection has favoured increased performance breadth at this range. In the field, basking snakes retreated to water when approached. Despite a decrease in swimming speed at lower temperatures, and the cost associated with reduced metabolic rate due to loss of body temperature, however, flight distances were independent of water temperature. We found that basking snakes retreated to water sooner when perched at lower heights, possibly indicating that N. sipedon are more vulnerable to predators when on low perches. Predicting water snake escape behaviour may require not only knowledge of variation both among snakes and in their environment, but also a better understanding of the interaction between the snakes and their natural predators.

Activity of fecal coliform bacteria measured by 4-methylumbelliferyl-ß-D-glucuronide substrate in the northern Adriatic Sea with special reference to marine snow

Activity of fecal coliform bacteria measured by 4-methylumbelliferyl-ß-D-glucuronide substrate in the northern Adriatic Sea with special reference to marine snow

The Os Coxae of a Digging Form of the Northern Water Vole, Arvicola terrestris (Rodentia, Arvicolidae)

Data on the morphology, relative growth and sexual dimorphism of the os coxae of a digging form of the northern water vole Arvicola terrestris (A.t. monticola) are given. Two hundred ninety-nine specimens (146 males and 153 females) caught in the Aran Valley (Spanish Pyrenees) were analyzed. The specimens were distributed into six classes of relative age, according to the skull morphology, kind of coat, moulting state, weight and sexual state. The morphological features of the os coxae in these specimens are similar to those described in other species of Arvicolidae. The hormonal effect upon the pelvis in adult females during pregnancy and parturition leads to the appearance of marked intersexual differences in the obturator foramen length, the pubis length, the pelvis length and, specially, in the pelvis height and the pubis width. By means of Becker's and Dunmire's procedures both sexes can be correctly discriminated in a 78.87 and a 76.4% respectively. Conjugating the variation patterns obtained with Becker's index and the pelvis height, we have obtained a more effective method of sexual differentiation (an 85.51% of correct discrimination).

Reduction of Ice Thickness on Northern Water Reservoirs

Many northern communities rely on open reservoirs as a water source during winter. In the north, open reservoirs can experience ice thicknesses of over 2 m, which can result in a loss in usable storage of up to 60% of the total reservoir volume. This loss increases the required total size of the reservoir and cost. This paper evaluates available methods of reducing the loss of storage to ice. Methods considered included the geometrical optimization of the design, reducing ice thickness, and shortening the period that storage is required. To allow evaluation of many different options, the study concentrated on theoretical aspects, with many options being evaluated with a numerical ice growth model. It is recommended that field tests be conducted on the most promising options. Results indicated that of the geometric factors considered, depth was the most important. To reduce ice thickness, many methods were considered. However only accumulating snow on the surface and the placement of insulation on the ice surface proved to be feasible. The study also found the time period of storage could be slightly reduced by accelerating ice decay in the spring.

The role of water ice clouds in the Martian hydrologic cycle

A one‐dimensional model for the seasonal cycle of water on Mars has been used to investigate the direction of the net annual transport of water on the planet and to study the possible role of water ice clouds, which are included as an independent phase in addition to ground ice and water vapor, in the cycle. The calculated seasonal and spatial patterns of occurrence of water ice clouds are qualitatively similar to the observed polar hoods, suggesting that these polar clouds are, in fact, an important component of the water cycle. A residual dry ice cap in the south acts as a cold trap which, in the absence of sources other than the caps, will ultimately attract the water ice from the north cap; however, in the presence of a source of water in northern mid‐latitudes during spring, it is possible that the observed distribution of vapor and ice can be in a steady state even if a residual CO2 cap is a permanent feature of the system.

Metabolic acclimation in three species of sympatric, semi-aquatic snakes

Abstract 1. 1. Metabolic rates of brown water snakes (Nerodia taxispilota), northern water snakes (N. sipedon), and eastern cottonmouths (Agkistrodon piscivorus), acclimated to 22 and 32°C, were measured over ambient temperatures of 4–36°C and at 32°C during acclimation from 22 to 32°C. 2. 2. There was statistically significant variation in metabolic rate between acclimation temperatures and among species even though metabolic rate was adjusted for the effects of body mass and ambient temperature and all snakes were collected in the same area. 3. 3. Northern water snakes acclimate more rapidly and to a greater degree than do brown water snakes and eastern cottonmouths. 4. 4. Rate of acclimation in these three species of snakes is a significant function of body mass with small snakes acclimating more rapidly than large ones. 5. 5. Interspecific differences in rate and degree of acclimation suggest that acclimational capability is related to these species' geographic distributions and seasonal variations in behavior.

Paleocene lakes of the central rocky mountains, Western United States

Lacustrine environments are well developed in the Paleocene to early Eocene sedimentary sequences in the intermontane basins of the central Rocky Mountains. The available evidence points toward a widespread episode of lake formation in the middle-late Paleocene (Torrejonian-Tiffanian) followed by a second major period during the latest Paleocene to early Eocene (Clarkforkian-Wasatchian). The earlier period of lake formation is dominated by relatively shallow, although often areally extensive, freshwater lakes associated with fluvial and paludal environments. In basins in northern Wyoming and Montana, a high clastic input prevailed. Thich mudstone, often structureless, marks the deep-water facies of these lakes, with tabular sandstone, lenticular carbonate and lignite occurring along the fluviodeltaic margins. Farther south and west, in Colorado and Wyoming, alkaline lakes dominated by carbonate deposition were prevalent. The appearance and disappearance of standing water in both northern and southern basins may be more closely controlled by tectonics than by climate: most evidence points toward prevailing humid sub-tropical conditions until the very end of the Paleocene.

A Dynamical Interpretation of the Tritium Maximum in the Central Equatorial Pacific

Abstract The tropical tritium distribution between 1974 and 1981 is characterized by a maximum along the equator centered between 125° and 145°W. It signifies that this region has received the maximum input of high northern latitude water. A dynamical interpretation of the maximum shows that it can be explained by the strength of the Sverdrup circulation in the central equatorial Pacific where there is a strong zonal convergence in the North Equatorial Countercurrent (NECC) and a strong meridional geostrophic flow towards the equator.

Oceanographic variability off Ecuador associated with an El Niño event in 1982–1983

The development of the 1982–1983 El Niño event is described by reference to the oceanographic conditions prevailing off Ecuador during the period 1982–1984. The first signs of the anomaly's onset off the Ecuadorian coast were observed in August 1982: the 16°C isotherm was found some 50 m deeper than normal along 82°30′W; this observation preceded by approximately 2 months the rapid rise in sea level, the appearance of warm sea surface temperature (SST) anomalies, and heavy rainfalls. By February 1983, the whole area off Ecuador was covered by very warm (29°–30°C) and low salinity (less than 33.0 parts per thousand) surface water. Two mechanisms seemed to be involved in the formation of the low‐salinity water: advection of northern water and dilution by local rainfall. Although the ocean surface was 4°C warmer than normal, the most notable changes took place throughout the water column: a strong depression of the thermocline and all the isotherms down to 15°C, the largest anomalies being observed over the 100‐m water column, up to 9°C at 50‐m depth. During the subsequent months SSTs continued to increase; thus the highest SST anomalies (6.3°C) were observed in May and June. Recovery from the 1982–1983 anomaly started in July 1983 with a general uprising of the isotherms and a fall in sea level. By October, the warm SST anomalies had dropped to 1.5°C. In November 1983, the presence of the equatorial front also attested to the return to normal of the oceanographic conditions in the region.

Northern Water Quality Monitoring Workshop Observations, Conclusions, Recommendations

Abstract Development continues to occur in the North. With development, there is the potential for ecological damage. This is particularly true in the North, with its harsh environment coupled with its fragile ecosystems. One of these systems, the aguatic ecosystem, is the focal point of this special issue of the Water Pollution Research Journal of Canada. The ten preceedinq papers were presented at the Northern Water Quality Monitoring Workshop, held in Yellowknife, May 4-7, 1987. The Workshop was organized into three basic stages. Day 1 was devoted to invited presentations from data users while days 2 to 4 were devoted to scientific presentations on: General Monitoring, Mining and Hydrocarbons. The scientific presentations were followed by Workgroup Sessions and a Plenary session daily. This paper attempts to highlight the various views and opinions, often without creditation, from the verbatim transcripts of the invited presentations (day 1), Workgroup Sessions and Plenary Sessions (days 2-4) found in Inland Waters/Land Directorate, Technical Workshop Series No. 7, Northern Water Quality Monitoring, 1988.

Histological aspects of natural eustrongyloid infections of the northern water snake, Nerodia sipedon.

Encapsulated as well as unencapsulated fourth stage larvae of Eustrongylides sp. were found in four northern water snakes, Nerodia sipedon, from Virginia. Unencapsulated nematodes occurred within muscle, subcutaneous tissue and in the coelom. Encapsulated nematodes occurred in three forms: recently encapsulated, degenerating, or sclerotic; they were found on the mesentery, in muscle and subcutaneous tissue. Encapsulation was associated with muscular hypotrophy, fibroplasia and eosinophilia.

Opening of the Japan Sea and Marine Biogeography during the Miocene

A sharp changeover of benthic molluscs from warm water to cold water faunas is widely recognized in the Japan Sea coast early Middle Miocene deposits dating from about 15 Ma ago and lying within the Blow's N. 9 planktonic foraminiferal zone. The change in the molluscan faunas is attributable to a regional change in paleogeography around the Japan Sea. Recent paleomagnetic work shows that the clockwise rotation of Southwest Japan took place within a very short interval, probably between 15 and 14Ma ago, at about the same time as the faunal change. The sharp change in marine faunas may be reasonably explained by the rotation and opening of the Japan Sea. As Southwest Japan rotated clockwise around the pivot located in the northern East China Sea, the seas around the Tsushima Straits, a passageway of the warm Kuroshio Current, might be closed. The Japan Sea was turned to open toward the north, and thus brought the fauna under the influence of cold, northern water.

The evolving structure of an upwelling filament

The evolution of an upwelling filament was studied over a 2‐week period by using satellite infrared images, and its thermohaline structure was mapped in situ. The surface velocity field consisted of a large meander extending offshore for at least 300 km. The northern branch was ∼40 km wide, flowing offshore at a peak velocity of 0.55 m/s; the southern branch was flowing inshore at 0.35 m/s. The offshore transport was more than 106 m3 s−1, larger than the Ekman transport. The meander was unstable to barotropic instabilities at a scale of ∼15 km. From a succession of images a surface convergence γ ≈ 8·10−6 s−1 over 20 km was observed near the sharp front limiting the filament to the south. The ∼350 m width of the front indicates a separation of scales between the large‐scale strain field and the mixed‐layer turbulence parameterized with an eddy diffusion coefficient KH ≈ 0.25 m2 s−1. Thermohaline layers that originated at the convergence near the sharp front suggest a secondary circulation subducting denser waters to the south underneath the lighter northern water.

Metals in riparian wildlife of the lead mining district of southeastern Missouri.

Five species of riparian vertebrates (425 individuals) primarily representing upper trophic levels were collected from the Big River and Black River drainages in two lead mining districts of southeastern Missouri, 1981–82. Big River is subject to metal pollution via erosion and seepage from large tailings piles from inactive lead mines. Black River drains part of a currently mined area. Bullfrogs (Rana catesbeiana), muskrats (Ondatra zibethicus), and green-backed herons (Butorides striatus) collected downstream from the source of metal contamination to Big River had significantly (ANOVA, P<0.05) higher lead and cadmium levels than specimens collected at either an uncontaminated upstream site or on Black River. Northern water snakes (Nerodia sipedon) had elevated lead levels below the tailings source, but did not seem to accumulate cadmium. Levels of lead, cadmium, or zinc in northern rough-winged swallows (Stelgidopteryx serripennis) were not related to collecting locality. Carcasses of ten bank swallows (Riparia riparia) collected from a colony nesting in a tailings pile along the Big River had lead concentrations of 2.0–39 ppm wet weight. Differences between zinc concentrations in vertebrates collected from contaminated and uncontaminated sites were less apparent than differences in lead and cadmium. There was little relationship between metal concentrations in the animals studied and their trophic levels. Bullfrogs are the most promising species examined for monitoring environmental levels of lead, cadmium, and zinc. Downstream from the source of tailings, bullfrogs had markedly higher levels of these metals in most of their tissues. The species is also widely distributed in North America, easily caught, and relatively sedentary.

Contiguous distribution of two species of Cebus monkeys in El Tuparro National Park, Colombia.

The geographic distribution of two congeneric monkeys (Cebus albifrons and C. apella) was studied in El Tuparro National Park in the llanos of eastern Colombia. Extensive trips were undertaken by land and river to collect 268 precisely located groups of these two species. The distributions of these monkeys were generally mutually exclusive and parapatric, contrasting with their known sympatry in closed-canopy rainforest farther to the south. The replacement of one species by the other was abrupt along the northern water courses in the park; however, the two species' ranges partially overlapped and contained islands of sympatry towards the southern parts of the park, where forests are more extensive. Along the rivers, C. albifrons was found in seasonally inundated forests and woodlands that were seldom entered by C. apella. Such inundatable vegetation was extensive in downriver sites in the typically flat llanos geography of this part of Colombia. Although some differential use of habitat was demonstrated, many forests containing the two species seemed essentially identical so that historical precedence, competition, or both may also be posited to partially explain the distributions, although this remains to be demonstrated.

Errata: The Effect of Body Temperature and CO₂ Breathing on Ventilation and Acid-Base Status in the Northern Water Snake Nerodia sipedon

Previous articleNext article No AccessErrata: The Effect of Body Temperature and CO₂ Breathing on Ventilation and Acid-Base Status in the Northern Water Snake Nerodia sipedonPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 56, Number 3Jul., 1983 Article DOIhttps://doi.org/10.1086/physzool.56.3.30152613 Views: 1Total views on this site Journal History This article was published in Physiological Zoology (1928-1998), which is continued by Physiological and Biochemical Zoology (1999-present). Copyright 1983 The University of ChicagoPDF download Crossref reports no articles citing this article.

The Effect of Body Temperature and CO2Breathing on Ventilation and Acid-Base Status in the Northern Water Snake Nerodia sipedon

Oxygen uptake (Ṁo2), ventilation (V̇E), and arterial pH (pHa) were measured in catheterized, unanesthetized water snakes (Nerodia sipedon) in a head-body plethysmograph, while the snakes breathed either room air or a hypercapnic (5.2% CO2) gas mixture. Measurements were made at 15, 25, and 30 C. Pulmonary ventilation and oxygen uptake increased with body temperature (Tb) during both room-air and CO₂ breathing. However, Ṁo₂ increased in greater proportion, so that the air convection requirement (ACR = V̇E/Ṁo2) decreased with increasing Tb. As a result, arterial pH decreased by −0.012 pH units/°C in animals breathing room air, and the pH changes resulted in a relative constancy of the charge distribution on blood proteins (αPr). Despite the relative hyperventilation seen in snakes, both pHa and αPr are similar to values observed for other reptiles. Snakes breathing CO₂ for 30 min showed a higher ventilation and a lower pHa at each Tb compared with room-air breathers. Temperature-induced changes in V̇E were due largely to changes in respiratory frequency, while CO₂ breathing increased V̇E primarily by increasing tidal volume.

Physical evolution of Tasman Sea Eddy J

The evolution of warm-core eddy J was followed from March 1979 until May 1980. From March to October 1979, eddy J developed a deep surface mixed layer that, after summer capping, became a subsurface 'signature' for subsequent identification. During the first half of the observation period, eddy J was subjected to frequent peripheral injections of northern water, mainly from the East Australian Current but on one occasion from a northern eddy. Between mid-December 1979 and early February 1980, the signature layer of eddy J moved on top of the signature layer of another eddy. This is suggested to be an indication of the coalescence of the two eddies. The prehistory of eddy J was conjectured from the nature of a signature layer that the eddy already had in March 1979.