Seasonal Variations In Water Temperature Research Articles

Seasonal variation of water temperature in the Seto Inland Sea

The seasonal variation of water temperature in the Seto Inland Sea, Japan is examined using data analysis and numerical experiments and is shown to be controlled by heat exchange through the sea surface and horizontal heat dispersion from the Pacific Ocean. The average water temperature goes down from the Pacific Ocean to the center of the Seto Inland Sea indicating that 4.0 to 6.0×1015 cal day−1 (1.6 to 2.5×1016 joule day−1) of heat is transported from the Pacific Ocean to the Seto Inland Sea and is lost through the sea surface. The amplitude of seasonal variation of water temperature is large at the center of the Seto Inland Sea and the maximum water temperature is reached first at Bisan Straits and last at Iyo-Nada.

Biological observations on sharks caught by sport fisherman of New South Wales

Between 1979 and 1982, 523 sharks representing four families and 13 species were examined from sport fishing catches off New South Wales. Additional catch data were available from records of the Sydney Game Fishing Club extending from 1953 to 1979. The species composition of sharks caught changes through the year, probably as a result of seasonal variations in water temperature. Prionace glauca and Isurus oxyrinchus are most abundant in the catches during the cooler months from May to November. Galeocerdo cuvieri, Carcharhinus brevipinna, C. longimanus, C. falciformis, C. limbatus and Sphyrna lewini are taken principally during the warmer months from December to April. The sex ratio of P. glauca and Sphyrna zygaena changes through the year due to a seasonal influx of gravid females. At least six of the species examined give birth off New South Wales and, apart from C. falciformis, all of these appear to have restricted breeding seasons. P. glauca and S. zygaena feed mainly on cephalopods and to a lesser extent on fish, I. Oxyrinchus principally on fish, and G. cuvieri mostly on fish, birds, unidentified mammals and cephalopods.

かつら沢貯留水池における密度躍層の季節的変化

The seasonal variation of water temperature and suspended solid concentration (SS) were measured in Katsurazawa Reservoir in a period from May, 1978 to April, 1979, Measurements were carried out at a station 50-100m from the dam site.In early spring the reservoir was filled with water of low temperature and high SS which was caused by the melting snow. The inflow water formed the transitional SS layer at the same depth as thermocline in spring and early summer, In the circulation period after summer, both the thermocline and the SS transitional layer descended toward the bottom. In November and December, the latter remained at a depth of about 30m after the former had disappeared, showing that the thickness of the surface mixing layer could not be adequately estimated only by the apparent thermocline. Concentration of SS increases exponentially with depth in each of the surface and the bottom layers. The vertical gradients change under the influence of seasonal climate condition. In the heating period, water density of the surface layer is much lower than in the bottom layer, and so the density stratification is stable. On the other hand, the gradient of vertical distribution of water density is small and the stratification is unstable in the cooling period.

Les populations néoténiques de Triturus helveticus Raz. des Causses et du Bas-Languedoc. II. Écologie

The physical, chemical, and biotic characteristics of the ponds where neotenic populations of Palmate newts are found in Southern France are described. The frequency of neoteny is high in permanent ponds, at an altitude ranging from 400 to 700 m, on arid limestone plateaux with a yearly rainfall of 1500-2000 mm. In such areas there are large seasonal variations of water temperature, ranging from + 1 to + 28°C, water remaining cold (below + 15°C) for 8 to 10 months during the year. The saline content of water is low, as shown by conductivity figures (less than 200 μmhos/cm/cm²). No iodine deficiency was ever found in the ponds of the study area. A correlation has been found between the frequency of neoteny and the water concentration in Ca, Mg and particularly K (which may account for 35-40 % of the cations). The aridity of the area surrounding the pools can also contri¬ bute to the selection of neotenic individuals, paedogenesis being of obvious adaptive value in such an environment.

Estimated, in situ, rates of egg production for the copepod centropages typicus (Krøyer) in the new york bight

Centropages typicus (Krøyer) and Pseudocalanus sp. are the two predominant copepods in the Continental Shelf waters immediately south of Long Island, New York. The estimated, in situ, rate of egg production for Centropages typicus ranged from 5 to 230 eggs female −1 day −1 during this study. Variability was partly attributed to seasonal variation in water temperature and partly to variations in the physiological condition of individual females. It could not be shown that the ability to produce eggs varied seasonally due to factors related to food. Egg production by Pseudocalamus sp. is probably from 1–10 eggs female −1 day −1. The two reproductive behaviours result in average abundances of adults that are approximately the same, although the peaks are at different times of the year, indicating that Centropages typicus has a higher mortality between the egg and adult stages than Pseudocalanus sp.

A gravity-flow column to provide pesticide-laden water for aquatic bioassays.

Concentrations of mirex among individual tanks in each test were not statistically different at the 5-percent significance level; whereas, differences in mirex concentrations in tank water among experiments were significant. Paired comparisons indicated statistical differences between the first and second, and the second and third experiments, but not between the first and third experiment. These differences in mean mirex concentrations in tank water may have been caused by seasonal variations in water temperature. Fluctuations in the mirex concentrations within individual tanks were not significant.

Seasonal and daily dynamics in pelagic larvae of marine shelf bottom invertebrates in nearshore waters of Kandalaksha Bay (White Sea)

Seasonal and daily population dynamics have been studied in pelagic larvae of littoral and upper-sublittoral bottom invertebrates in the plankton of the shallow, narrow Velikaya Salma Sound, which connects the inner and outer areas of the Kandalaksha Bay in the western part of the White Sea. Hydrologically, this Sound is characterised by a clearly defined cycle of great seasonal variations in water temperature coupled with more or less stable salinities and regular, pronounced semi-diurnal tides corresponding to daily and lunar monthly tidal cycles. The seasonal dynamics of larvae in the Sound reflect differences in occurrence of spawning periods in local waters of various species and systematic groups of bottom invertebrates. These differences are caused by the correlation of spawning periods of local species of different zoogeographical origin with the different water temperatures. They reflect, also, lunar periodicities of spawning and larval hatchings. The daily dynamics of larval abundancies are related to the daily spawning rhythms of many species with pelagic development affected by the daily tidal cycles of the Velikaya Salma Sound. A daily invasion of the Sound by pelagic larvae of bottom invertebrates from the inner and the outer parts of the Kandalaksha Bay occurs at ebb tide, and also at flood tide; the rhythms of the invasions coincide with the daily spawning rhythms of the Sound's invertebrates. From literature data summarized by Mileikovsky (1958a, b, 1960a, b, c, 1961, 1965, 1968, 1970), it is concluded that seasonal, lunar and daily (tidal) reproductive periodicities for the marine shallowshelf bottom invertebrates concerned, follow world-wide ecological patterns. It is evident that the effects of these rhythms upon the population dynamics of pelagic invertebrate larvae, as demonstrated by the present data on the Velikaya Salma Sound (White Sea), must also follow world-wide regularities.

UNIALGAL CULTURES OF CLADOPHORA GLOMERATA (L.) KÜTZ.(1) (2) : I. RESPONSE TO TEMPERATURE.

Unialgal cultures of Cladophora glomerata (L.) Kütz. grew with increasing vigor at temperatures between 15 and 30 C. Vegetative cells were killed upon freezing or when exposed to temperatures above 30 C. No growth occurred at 5 C and only slight growth was observed at 10 C. Effects of near lethal temperature on C. glomerata were dependent upon the duration of exposure in addition to the actual temperature attained. The response of this alga to various temperatures under culture conditions is in accord with tolerance limits established for naturally occurring populations. It seems probable that the annual periodicity of C. glomerata is regulated in large measure by seasonal variations in water temperature, greatest abundance coinciding with water temperatures between 15 and 30 C.

キハダ,メバチ,クロカワのカロリン,マーシャル諸島付近における游泳層の季節変化について―IV

The author studied the seasonal variations in water temperature at various depths and sub-regions in the area of Caroline and Marshall Islands. The seasonal variation in the water temperature at surface and 50 meters in depth was found to be different from those of 150, 200 and 300 meters in depth. In the earlier period of the year the water temperatures at surface and 50 meters in depth were lower than those of the latter period but the water temperatures at the other deeper layers in the earlier period were higher than those of the latter period of the year.