Periods Of Cold Weather Research Articles

Phytoplankton death and nitrification at low temperatures

An extremely tight coupling was found between microalgal biomass decreases and nitrification in a shallow dirt pond filled with coastal seawater after a spring tide. Degradation of half the phytoplankton standing crop and transformation into dissolved nitrate occurred within 2–3 days without accumulation of intermediate compounds such as ammonium or nitrite. The event time scale was of the order of one week, starting with a sub-zero water temperature, followed by a two-fold decrease in chlorophyll- a and particulate nitrogen, a simultaneous two-fold increase in nitrate over 48 h, and ending with recovery of the phytoplankton population within five days. A second event then started with a new period of cold weather. These mesocosm events were duplicated in a 2-1 microcosm, showing that nitrification had taken place in the water column for the most part, and can proceed at sub-zero temperatures very efficiently.

A High-Resolution Anion Profile of an Ice Core From Dolleman Island, Antarctic Peninsula (Abstract)

In January 1986, a 133 m ice core, with an estimated age at the bottom of 300-350 years, was collected (using an electromechanical drill) on Dolleman Island (70° 35.2′S, 60°55.5′ W; 398 ma.s.l.; 10 m temperature −16.75°C). The site lies on the east coast of the Antarctic Peninsula and has a continental-type climate dominated by perennial sea ice in the Weddell Sea. The core is being analysed for a range of chemical impurities, in order to assess their potential as indicators of past climate.High-resolution (10-15 samples a−1) continuous profiles of the anionic species Cl−1, NO3− and SO42−, together with the cation Na+, have been measured on a section of the core from 26 to 71 m depth. The core has previously been dated between 0 and 32 m depth using the δ18O profile (Peel and others 1988). Lack of δ18O data for the section 32-71 m forced us to seek an alternative method of dating.Biogenic outgassing of sulphurous gases from the ocean and subsequent photochemical oxidation contribute an excess of sulphate over that derived from the marine aerosol. We show that excess sulphate, calculated as(concentrations in Eq. 1−1 and assuming that all measured Na+ is derived from sea salt), is highly seasonal in character, and annual horizons are well preserved over the whole of the core. This enabled us to determine the chronology to 71 m depth, and date the bottom of this section as 1844 ± 5 years.Cl− is derived mainly from sea salt. Its profile in the core is also seasonal in character, with peaks that tend to occur in late summer, reflecting the period of minimum sea-ice extent in the Weddell Sea, and therefore maximum source area for the uptake of sea salt. From instrumental meteorological records, Limbert (1974) showed that there were three extended periods of warm or cold weather in the Antarctic Peninsula between 1903 and 1944. During the two 4 year cold periods, when the summer break-up of sea ice in the Weddell Sea is likely to have been reduced, we found that the annual flux of Cl− to the Dolleman Island snow-pack was lower than the average. Conversely, the 3 year warm period showed a peak in the values of annual flux of Cl−. We therefore propose that Cl− can be used as a palaeoclimatic indicator for sea-ice extent.Extending our chloride data into the latter half of the nineteenth century (before the earliest continuous instrumental records for the Antarctic), we found three distinct peaks in the values of annual flux of Cl−. We suggest that the period 1850-60 was marked by a decrease in Weddell Sea ice extent (due perhaps to a warm period), followed by an extended period of increased sea ice. There were then two periods of much-reduced sea ice during (approximately) 1885-1890 and 1895-1900, with an intervening period of greatly increased ice coverage. These events are in good agreement with the warm and cold periods which Aristarain and others (1986) identified in the deuterium profile from James Ross Island.

A High-Resolution Anion Profile of an Ice Core From Dolleman Island, Antarctic Peninsula (Abstract)

In January 1986, a 133 m ice core, with an estimated age at the bottom of 300-350 years, was collected (using an electromechanical drill) on Dolleman Island (70° 35.2′S, 60°55.5′ W; 398 ma.s.l.; 10 m temperature −16.75°C). The site lies on the east coast of the Antarctic Peninsula and has a continental-type climate dominated by perennial sea ice in the Weddell Sea. The core is being analysed for a range of chemical impurities, in order to assess their potential as indicators of past climate. High-resolution (10-15 samples a−1) continuous profiles of the anionic species Cl−1, NO3 − and SO4 2−, together with the cation Na+, have been measured on a section of the core from 26 to 71 m depth. The core has previously been dated between 0 and 32 m depth using the δ18O profile (Peel and others 1988). Lack of δ18O data for the section 32-71 m forced us to seek an alternative method of dating. Biogenic outgassing of sulphurous gases from the ocean and subsequent photochemical oxidation contribute an excess of sulphate over that derived from the marine aerosol. We show that excess sulphate, calculated as (concentrations in Eq. 1−1 and assuming that all measured Na+ is derived from sea salt), is highly seasonal in character, and annual horizons are well preserved over the whole of the core. This enabled us to determine the chronology to 71 m depth, and date the bottom of this section as 1844 ± 5 years. Cl− is derived mainly from sea salt. Its profile in the core is also seasonal in character, with peaks that tend to occur in late summer, reflecting the period of minimum sea-ice extent in the Weddell Sea, and therefore maximum source area for the uptake of sea salt. From instrumental meteorological records, Limbert (1974) showed that there were three extended periods of warm or cold weather in the Antarctic Peninsula between 1903 and 1944. During the two 4 year cold periods, when the summer break-up of sea ice in the Weddell Sea is likely to have been reduced, we found that the annual flux of Cl− to the Dolleman Island snow-pack was lower than the average. Conversely, the 3 year warm period showed a peak in the values of annual flux of Cl−. We therefore propose that Cl− can be used as a palaeoclimatic indicator for sea-ice extent. Extending our chloride data into the latter half of the nineteenth century (before the earliest continuous instrumental records for the Antarctic), we found three distinct peaks in the values of annual flux of Cl−. We suggest that the period 1850-60 was marked by a decrease in Weddell Sea ice extent (due perhaps to a warm period), followed by an extended period of increased sea ice. There were then two periods of much-reduced sea ice during (approximately) 1885-1890 and 1895-1900, with an intervening period of greatly increased ice coverage. These events are in good agreement with the warm and cold periods which Aristarain and others (1986) identified in the deuterium profile from James Ross Island.

Improvement in the efficiency of stocking lakes with larvae of Coregonus albula L. by delaying hatching

Low survival of vendace ( Coregonus albula) eggs incubating on natural spawning grounds (due to silting, oxygen deficits and action of predators) is discussed as one of the reasons for the great fluctuation in numbers of commercial fish. Incubation of eggs in hatcheries where the survival rate averages 60% could compensate for the great numerical disparity between the eggs spawned naturally and those taken for hatcheries. In the absence of the effects of mass stocking of lakes with vendace larvae, one can conclude that apparent mortality during the larval stage also determines the strength of the successive year-class. Vendace larvae are usually stocked immediately after the ice cover recedes from lakes. At this time they often face a period of cold weather when water temperature is low and food organisms are scarce. Poor environmental conditions cause slow growth of larvae. This increases the period of highest vulnerability of the larvae to predation. It is possible to accelerate the growth of larvae by synchronizing the time of stocking with the development of favourable thermal conditions and food availability in lakes. In Polish climatic conditions the first 10 days of May seem to be a suitable time for stocking lakes. A technique for delaying vendace egg hatching by cooling the hatchery water has been developed. It enables hatching of vendace to be delayed from the beginning of April until the beginning of May, thereby inducing mass hatching of larvae when lake conditions are optimal for stocking.

Notes on the Population Ecology of Perognathus fallax (Rodentia: Heteromyidae) in Southern California

-A population of the San Diego pocket mouse, Perognathus fallax, from San Diego County, California, was monitored by monthly live trapping from September, 1978, through August, 1980. Peaks in population size were observed each spring and the precise timing of these peaks varied between years. A dramatic decline in density occurred as the study was concluded in the summer of 1980. Reproductive activity displayed significant seasonal heterogeneity, with the highest proportions of breeding adults being observed in the spring. Similarly, survival was also found to vary seasonally, with significantly lower survival in the spring. There were no significant differences in survival rates between sexes. The average P. fallax remained on the study site for 5.2 ? 1.4 months after first capture. The deserts of North America support diverse rodent communities and the primary thrust of recent ecological research on these communities has been to identify factors which regulate species diversity and determine community structure (Brown, 1973; Hafner, 1977; Rosenzweig and Sterner, 1970). Although life history characteristics of component populations may be important to patterns of species diversity (M'Closkey, 1972), there is a general paucity of detailed demographic studies on rodents inhabiting arid environments (Conley et al., 1977). The San Diego pocket mouse (Perognathus fallax Merriam) is one of seven perognathine species occurring in San Diego County, California (Bond, 1977). It inhabits open, sandy areas of both the Upper and Lower Sonoran life-zones of southwestern California and northern Baja California (Bond, 1977; Ingles, 1965). Adult individuals weigh about 20 g and rely primarily on seeds for food (Meserve, 1976). Torpor is employed during periods of cold weather (Bartholomew and Cade, 1957; MacMillen, 1964) and it has been shown that P. fallax survival is independent of drinking water (MacMillen, 1964). Several workers have reported the presence of P. fallax on their study plots (M'Closkey, 1972; MacMillen, 1964; Meserve, 1976), but only general information about the population ecology of this species was gathered in these studies because of low densities and sporadic

Feeding activity of ducks in relation to diel emergence of chironomids

The diel emergence of chironomids, an insect group important as food item for both adult and young ducks, was studied in relation to the feeding activity and behaviour of ducks on a northern Swedish lake (66°3′ N, 23°46′ E) during 1975–1978. Emergence and swarming activity of chironomids peaked between 0800 and 1200. Emergence occurred even on windy days, but almost completely ceased during periods of rainy and cold weather. Swarming occurred mainly around 1000 on warm days with little or no wind. During such occasions, a large number of chironomids were observed over the entire surface of the lake. Dabbling ducks fed throughout a 24-h period, but peak feeding coincided with periods of chironomid emergence. Surface feeding by both dabbling and diving ducks on chironomid imagines present on the water surface and on emergent vegetation increased during these periods of chironomid emergence.

Physiological adaptations to low temperature in freezing-tolerant Phyllodecta laticollis beetles

1. 1. Adult beetles of the species Phyllodecta laticollis, overwintering at exposed sites beneath loose bark of dry trees, were found to tolerate freezing to about −42°C in winter. 2. 2. Phyllodecta laticollis beetles are also freezing-tolerant in summer having a low temperature tolerance limit of about −9°C. 3. 3. The hemolymph of Phyllodecta laticollis contained nucleating agents the whole year through. The supercooling points of the beetles varied from about −5°C in summer to about −7°C in winter. 4. 4. The increase in the freezing tolerance of the beetles from summer to winter is correlated with an accumulation of glycerol to high concentrations; the body fluid of the beetles reaching osmolality values of about 2500 mOsm. The osmotic contribution of glycerol seems to account for almost the whole increase in hemolymph osmolality. In winter, the high cold-hardiness of the beetles seems to be due to the colligative properties of glycerol. 5. 5. From autumn/winter to spring, however, there is a shift in the cold-hardiness. Beetles having the same hemolymph osmolalities and glycerol concentrations tolerate about 10°C lower temperatures in spring than in autumn. This increased freezing tolerance in spring seems to be based on other mechanisms than colligative ones. 6. 6. The increased cold-hardiness in spring might be of great importance to Phyllodecta laticollis, in that the glycerol concentration might decrease during the day due to sun exposure at a time when the beetles still are likely to be exposed to low temperatures at night or sudden periods of cold weather. 7. 7. The total amino acid concentration of the beetles varied from about 165 mMolal in summer to about 300 mMolal in winter. In spring and autumn the amino acid concentration was the same, so that the shift in cold-hardiness of Phyllodecta laticollis could not be explained by differences in total amino acid concentrations.

Effect of low winter temperatures on milk production of dairy cows grazed on farms in a warm temperate climate (Australia)

Two-day milk production figures for dairymen at Armidale (31° S Lat.) and Goulburn (35° S Lat.), Australia, were compared with minimum daily temperatures. Comparisons were made between production levels on days with temperatures above and below 0°C, and between days with varying intensities of cold: differences in production were minor. The infrequent, more prolonged periods of cold weather (“cold” being days on which the minimum temperature was below 0°C) were also associated with only very slight reductions in milk output; and the most pronounced decline in production was not attributable to low temperatures. Although short-term fluctuations in output were not related to low temperature events or low temperatures in combination with rain, thermal stress on plant growth during winter contributed to a seasonal downturn in production and below-average annual milk yields in areas with low winter temperatures.

Deterioration of visibility at Bombay airport due to atmospheric pollutants

As seen from round-the-clock current, weather observations, the total number of occassions in the year when the visibility over Bombay airport deteriorated to less than 3000 metres was only 9 in 1956 whereas the figures rose to 574 in 1970. This large increase, it has been found, is mainly due to the markedly high frequency of visibility deterioration during recent years in the early hours of the morning of the cold weather period, December to February. The poor visibility conditions seem to develop generally not due to moist phenomena like mist or fog but due to suspended particulate matter and smoke factory chimneys and domestic fires which move or stagnate over the eastern side of the aerodrome under the prevailing and conditions. It has been shown that the concentration of factories/population towards the east and north of the airport is the source of these atmospheric pollutants. The conditions under which prolonged spells of poor visibility, occur have also been discussed.

Genetic Improvement in Ponni (Mashuri) Rice.

Ponni (Mashuri) is a medium duration rice variety largely grown during Sambo and Thalodi seasons in Tamil Nadu extending from August to February. It is known for its fine and good quality rice coupled with adaptability to monsoon conditions followed by cold weather period. But being a tall indica variety it is susceptible for lodging resulting in drastic reductions in yields. Therefore to improve this variety for plant type, high yielding with fine grains resembling that of Ponni and adaptability for monsoon period hybridization was effected with IR 8 in the year 1972. Twenty selections confirming to these objectives were finally evaluated in F 6 for the yield and yield components and grain type. It has been identified that genotypes P. 151, 162, 166, 174 and 191 appear promising from their desirable level of expression of yield components, and higher yields coupled with the duration and grain type of Ponni.

Drainage of an ice-dammed lake, Okstindan, Nordland, Norway

Knudsen, N. T. 1978. Drainage of an ice-dammed lake, Okstindan, Nordland, Norway. Norsk geogr. Tidsskr. Vol. 32, pp. 55–61. Oslo. ISSN 0029-1951. Conditions during the drainage of an ice-dammed lake in Okstindan, Nordland, Norway are described. The observations in 1976 are discussed and compared with observations during other jokulhlaups. The drainage mechanism of this particular lake is discussed, and it is suggested that a period of cold weather, causing a pressure drop in the glacier's internal drainage system, released the hlaup.

Pre- and Postharvest Factors Affecting Textural Quality of Fresh Asparagus1

Abstract Factors determined to have a pronounced effect on shear-press peak-force values of asparagus, Asparagus officinalis L. included sample size, spear diameter, length of green, and preharvest temperature. Shear-press values were greater following periods of cold weather in early spring. Larger diameter spears had lower peak-force values than smaller spears, indicating that larger spears are more tender than smaller spears. The number and diameter of spears produced by a particular cultivar, and not differences between cultivars, were the characteristics observed to influence shear-press values. Shear-press max peak-force values correlated well with subjective and objective determinations of asparagus fiber.

Curling Deformations and Stresses of Insulated Rigid Pavements

The problems associated with freezing and thawing of the subgrade soil underneath highway and airfield pavements in countries with cold winters like Canada are well known. In the southern parts of Canada, the subgrade can be protected from freezing by a thick layer of granular material or a thin insulating layer. In northern regions, layers of granular materials or insulation can maintain the subgrade in a frozen condition.Previous studies have shown that extruded polystyrene foam is effective as an insulating material. However, the effect of this material on the physical behavior of pavements has not previously been investigated.To study the effect of a thin insulating layer on the curling deformation and thermal properties of rigid pavements two concrete slabs were cast in the field. One slab was laid over a 1½ in (4 cm) thick layer of styrofoam, while the second slab was cast over a 1½ in. (4 cm) thick layer of sand without insulation. A 10 in. (25 cm) subbase layer of compacted gravel was used underneath both slabs.Both slabs were instrumented from surface through foundation to determine the temperature distribution and to establish the curling behavior of the slabs. Periodic readings were taken during one warm and one cold weather period. The results derived from these readings have indicated that insulation reduces curling deformation of pavement slabs and does not significantly effect temperature gradients across their thickness.

Extended Storage of Quail, Chicken, and Turkey Eggs: 3. Tertiary Sex Ratio in Quail

INTRODUCTIONWHILE analyzing observations on embryos in stored and unstored Japanese quail eggs, some trends in sex ratio became apparent that, to our knowledge, have not been reported before.MATERIALS AND METHODSThe quail used in this study belonged to generation 13 of line 908 which was maintained by pedigreed single-pair matings. Non-inbred progeny, i.e. controls, were produced by random matings among non-inbred parents. Deliberately inbred progeny (F = 0.3125) were produced in the present trial by non-inbred parents in a cyclical mating system. Data from non-inbred progeny in the cyclical mating system were pooled with those of the controls.Eggs were collected daily for a total of five weeks starting March 2, 1966. At that time, birds were still recovering from a cold weather period which was reflected in substantial increases of egg production and fertility during the early weeks of the trial (Sittmann et al., 1971). Eggs were…

ADFREEZING OF LEDA CLAY TO ANCHORED FOOTING COLUMNS

The heaving force transmitted to [Formula: see text] (7.6-cm) diameter steel pipes by adfreezing in Leda clay was measured in the field for two consecutive winters. The maximum uplift force was approximately 6000 lb (2700 kg), which corresponds to an apparent adfreeze strength of about 12.5 p.s.i. (≈ 0.9 kg/cm2). It developed gradually during prolonged periods of cold weather, but dropped off rapidly during warming trends, although the whole soil profile remained below 0 °C. Adfreezing did not retard frost heave in the soil in the vicinity of the steel pipes.Agreement between experimental values for maximum uplift forces by adfreezing and values predicted by Dalmotov's equation suggests that such predictions can be used as a guide for design purposes if no other information is available.

The domestic tung industry today

AbstractThe tung tree (Aleurites fordii) requires a moderately acid soil, an annual rainfall of 45 to 70 in., and a long hot summer, yet it must have a period of cold weather in winter. These factors limit its culture in North America to a narrow belt along the Gulf of Mexico from Florida to Texas. The majority of the orchards presently consist of miscellaneous seedlings that are about 30 years of age. By replacing these with orchards of new varieties, on suitable soil, and by following recommended practices, growers can produce oil at lower costs than previously. However, crop loss from frost is still a serious problem. Machine harvesting is now a reality. During World War II the government requisitioned the entire domestic production of tung oil for military purposes, and regular customers had to turn to other products. This market has not yet been fully won back, and growers look to utilization research to improve the market.

St. Anthony Falls Navigation Project

St. Peter sandstone is a soft loosely bonded rock that disintegrates readily when subjected to flowing water. This type of foundation, encountered in the St. Anthony Falls project, called for careful geological investigating and testing. De-watering excavated areas required special precautions for the control of subsurface seepage. Deep seated steel sheet piling, wellpoint system and chemical grouting were adopted as essential construction safety measures. A type of structure was selected in order to assure that the foundation under and adjacent to the completed locks and dams would not be disturbed. Meticulous regulations of the pool levels within the metropolitan areas requires the use of control gates that will minimize interference with the operation of existing structures and utilities. Radiant heating and low pressure bubbler systems were adopted to keep the gates operable during cold weather periods. Railway bridge alterations made under sustained traffic required the coordination of planning and execution by the contractor, the operating agency, and the designing engineer.

Dubbing White Leghorn Pullets

A number of workers have reported on the practice of dubbing White Leghorn pullets. A majority of such reports have indicated some benefit from dubbing during the colder season of the year. Davis et al. (1953) reported approximately 20 percent greater production with dubbed birds at the Wyoming Station without a corresponding increase in feed consumption. Jones and Kohlmeyer (1950) reported better performance from dubbed birds during periods of cold weather but little difference in total annual egg production. Cole and Hutt (1954) reported no statistical difference in egg production between dubbed and control groups as measured by annual production but they indicated that a difference in favor of dubbed lots was present between treatments during cold weather.Since most of the work reported has been concerned with birds housed in floor pens and the response to dubbing associated with cold weather, the value of dubbing pullets housed in open …

Phenology of Spring Weeds in Norman, Oklahoma

Weed calendars were kept for January-May 1954 and 1955, involving 75 species, more than half native. Details are given for the 25 most abundant. Percentage of those initiating flowering reached a peak in April; of those actually in bloom, about mid-May. A list and tables are given for the commonest species by month, growth habit, and habitat, with tables of temperatures and precipitation for the two seasons. A study of the phenology of the weeds of Norman was initiated in January of 1954. The purposes of the investigation were to prepare a phenological calendar for the spring weeds and to determine the effects of weather on the phenology of these weeds. In practice field trips were made at least twice a week except during extended periods of cold or rainy weather. On each trip observations were made on foliation, exsertion of flower buds, flowering, fruiting and seed dissemination. From these data, graphic tables and phenological calendars were prepared. RESULTS During the two years of investigation, some phenological data were obtained on 75 herbaceous weeds in Norman. Some species that were present in 1954 were not found in 1955. On the other hand, eight new species were discovered in 1955. In analyzing the detailed record, for 1954 and 1955, it was observed that adequate records were obtained only on the more common species. In view of these facts, data are presented only on the 25 most abundant species. On the species in Table 1, the dandelion, Taraxacum officinale, flowered discontinuously throughout the year, even in December and January. The first plant to initiate anthesis in the spring, therefore, was the shepherd's purse, Capsella Bursa-pastoris. Relatively few new species started to flower in February or March, most of the species initiated flowering in April and a few new ones began to flower in May (Table 1). The flowering period of spring weeds was found to be comparatively long. Many of the earliest flowering species had anthoperiods of twelve or more weeks. Because of this, the peak of flowering of weedy species occurs about May 15. This contrasts markedly with shrubs and trees which reach their flowering maxima about May 1 and April 15 respectively (Table 2). In comparing the phenological weed calendars in 1954 and 1955 it will be observed that no species were in bloom by mid-February, 1954, This content downloaded from 157.55.39.208 on Fri, 14 Oct 2016 04:15:09 UTC All use subject to http://about.jstor.org/terms

Comparison of the Growth of Lake Trout Fingerlings from Eggs Taken in Seneca, Saranac, and Raquette Lakes

Conclusions 1. In hatchery practice, the relative growth rates of the fingerling lake trout of the three strains reared in New York State are obscured by two circumstances. First, because of a difference In spawning times, the fingerlings from eggs of wild fish from Seneca Lake usually start to feed nearly a month earlier than those taken from Raquette Lake, and 6 weeks earlier than those from Saranac Lake; thus, at any given time, comparison favors the older strains. Second, the strains which regularly start to feed earliest in the winter have the longest period of cold weather before spring and consequently the lowest average temperature. This tends to reduce the growth rate of the strains which start to feed earliest. A fair comparison of the growth rates requires a study at equal ages and an adjustment of growth rate to compensate for different water temperatures. 2. When adjustment of the growth rates for temperature differences has been made and the strains are compared at equal ages, the Seneca fin...