Effects Of Water Temperature Changes Research Articles

Effects of water temperature changes on the early life stages (egg and larvae) of walleye Pollock (Gadus chalcogrammus) – Laboratory experiments and field applications

The eastern coast of Korea (ECK) is the southern limit of walleye pollock (pollock) distribution in the North Pacific. Since the climate regime shift in the 1980s, pollock catch has decreased sharply, with <1 ton recorded annually since the 2000s. Pollock, a semi-demersal cold-water species, is greatly affected by sea surface temperature changes during its early life stages. This study analyzed the effect of different water temperatures (3.6, 5.1, 7.1, 10.0, 13.3, and 15.1 °C) on the survival and growth of fertilized pollock eggs and larvae to investigate whether the ECK is still suitable for the early life stages development of pollock. The hatching rate of eggs was 82%, 57%, and 4%, and the hatching period was 20.7, 11.6, and 5.6 d at 3.6, 10.0, and 15.1 °C, respectively. The larval size-at-hatch was the highest at 3.6 °C (5.14 mm) and lowest at 15.1 °C (4.24 mm). Above 10.0 °C, the hatching rate decreased rapidly, and the abnormality rate increased. Since the 1980s, the 10 °C isotherm in the ECK has been moving northward in winter, which is the pollock spawning season. Continuous warming of the ECK has thus been unfavorable for the early life stages of pollock. Overall, this study improves our understanding of changes in pollock abundance due to climate change.

Effects of water temperature changes on oxygen consumption and hematological factors in olive flounder Paralichthys olivaceus

Water temperature (WT) is a major environmental factor of metabolic rate in fish; it directly affects food intake, ammonia excretion, oxygen consumption (OC), growth, and survival. Thus, the purpose of this study was to investigate changes in the OC and the hematological response of olive flounder Paralichthys olivaceus because of WT changes. In Exp. I, WT was increased from 20°C to 29°C within 18 h and maintained at 29°C for 96 h. Then, WT was decreased from 29°C to 20°C within 18 h and maintained at 20°C for 24 h. In Exp. II, WT was decreased from 20°C to 11°C within 18 h and maintained at 11°C for 96 h. Then, WT was increased from 11°C to 20°C within 18 h and maintained at 20°C for 24 h. The Exp. III maintained that the Exp. I and II was consecutively. In Exp. I, the OC increased from 116.7 mg O2 kg−1 hr−1 to 317.5 mg O2 kg−1 hr−1 with increasing WT. In Exp. II, the OC decreased from 96.5 mg O2 kg−1 hr−1 to 71.3 mg O2 kg−1 hr−1 with decreasing WT. In Exp. III, OC tended to increase or decrease in inverse proportion to temperature. In Exp. I, cortisol, glucose, and aspartate aminotransferase (AST) values increased with increasing WT. In Exp. II, Cl−, osmolality, AST, and alanine aminotransferase (ALT) values significantly changed during the experimental period: glucose values increased, whereas cortisol values decreased with decreasing WT. Exp. III was shown to be a more stressful environment to olive flounder than Exp. I and Exp. II. The results of our study will be useful for evaluating current aquaculture procedures of olive flounder and developing techniques to minimize stress in aquaculture farms.

How Can We Make Pump and Treat Systems More Energetically Sustainable?

Pump and treat (P&amp;T) systems are still widely employed for the hydraulic containment of contaminated groundwater despite the fact that their usage is decreasing due to their high operational costs. A way to partially mitigate such costs, both in monetary and environmental terms, is to perform heat exchange (directly or with a heat pump) on the groundwater extracted by these systems, thus providing low-carbon and low-cost heating and/or cooling to buildings or industrial processes. This opportunity should be carefully evaluated in view of preserving (or even improving) the removal efficiency of the remediation process. Therefore, the heat exchange should be placed upstream or downstream of all treatments, or in an intermediate position, depending on the effect of water temperature change on the removal efficiency of each treatment step. This article provides an overview of such effects and is meant to serve as a starting reference for a case-by-case evaluation. Finally, the potentiality of geothermal use of P&amp;T systems is assessed in the Italian contaminated Sites of National Interest (SIN), i.e., the 41 priority contaminated sites in Italy. At least 29 of these sites use pumping wells as hydraulic barriers or P&amp;T systems. The total discharge rate treated by these plants exceeds 7000 m3/h and can potentially provide about 33 MW of heating and/or cooling power.

An experimental study of the effect of water bodies temperature on water heat pump performance

The purpose of this research is to study the effect of water temperature change in the reservoir on water heat pump performance. An experimental analyse is done on the heat pump station which depends on water as a heat source. The experimental results confirm that the ice formation has a negative effect on the heat exchange efficiency, and the increase in water source temperature slow down the ice formation rate which causes an appositive effect on the system performance.

THE EFFECT OF TEMPERATURE CHANGE ON ERYTHROCYTE PROFILE OF Carassius gibelio

A research on the effect of water temperature change on erythrocyte profile was conducted on Prussian carp (Carassius gibelio) from the Bardaca area (BiH). The study included 38 individuals which were divided into two aquaria, adapted to experimental conditions and then subjected to different temperature regime. The control group had constant water temperature of 10oC, while for treated fish water temperature was gradually increased to 20oC for three days. Conducted analysis of erythrocyte profile, which includes erythrocyte count, hemoglobin concentration, packed cell volume, MCV, MCH and MCHC showed that individuals exposed to temperature increase had significantly higher values of erythrocyte count and packed cell volume, while control individuals had higher values of MCH and MCHC.

Effects of Water Temperature Changes on the Oxygen Consumption Rhythm in the Japanese eel, Anguilla japonica

We investigated the effects of temperature changes on the oxygen consumption rhythm in Japanese eels, Anguilla japonica, using an automatic intermittent flow respirometer (AIFR). The endogenous rhythm of the oxygen consumption rate (OCR) in the eels (n = 18; 44-74 cm, 145-690 g), freshly collected by bag net from estuaries, was nearly synchronous with the tidal pattern of the estuarine collection site. The magnitude of mean OCR (mOCR) of eels showed variable range of 82.2 - 116.5 ml <TEX>$O_2\;kg^{-1}ww \;h^{-1}$</TEX> under constant conditions. In case of increasing temperature from 25 to <TEX>$38^{\circ}C$</TEX>, the OCR of eels exhibited a gradually increasing trend with a rhythmic pattern until <TEX>$36^{\circ}C$</TEX>. Above <TEX>$36^{\circ}C$</TEX> the rhythms of the OCR dampened and the OCR decreased rapidly at around <TEX>$36-37^{\circ}C$</TEX>. The OCR of the eels exhibited the maximum value at <TEX>$38^{\circ}C$</TEX>, and then it sharply decreased. The results suggested that the critical thermal maximum (CTM) regarding the endogenous rhythms of the eels was at around <TEX>$36-37^{\circ}C$</TEX> when water temperature increased at <TEX>$0.5^{\circ}C$</TEX>/14 h following the acclimation at <TEX>$25^{\circ}C$</TEX>. In case of decreasing temperature (<TEX>$0.5^{\circ}C$</TEX>/14 h) from 25 to <TEX>$0^{\circ}C$</TEX>, the OCR of the eels displayed a abrupt decrease up to <TEX>$23^{\circ}C$</TEX>, and between at 23 and <TEX>$20^{\circ}C$</TEX>, there was an agitation which showed a slight increase in the OCR with a duration of 1-2 days. Below <TEX>$9^{\circ}C$</TEX>, the OCR rhythm of the eels showed a constant state regardless of temperature decreasing. These results suggest that the Japanese eel has an upper incipient lethal temperature at <TEX>$36^{\circ}C$</TEX>, with a lower thermal limit at <TEX>$9^{\circ}C$</TEX>. The biochemical aspects of the eels influenced by water temperature need to be further studied.

Characterization Factors for Thermal Pollution in Freshwater Aquatic Environments

To date the impact of thermal emissions has not been addressed in life cycle assessment despite the narrow thermal tolerance of most aquatic species. A method to derive characterization factors for the impact of cooling water discharges on aquatic ecosystems was developed which uses space and time explicit integration of fate and effects of water temperature changes. The fate factor is calculated with a 1-dimensional steady-state model and reflects the residence time of heat emissions in the river. The effect factor specifies the loss of species diversity per unit of temperature increase and is based on a species sensitivity distribution of temperature tolerance intervals for various aquatic species. As an example, time explicit characterization factors were calculated for the cooling water discharge of a nuclear power plant in Switzerland, quantifying the impact on aquatic ecosystems of the rivers Aare and Rhine. The relative importance of the impact of these cooling water discharges was compared with other impacts in life cycle assessment. We found that thermal emissions are relevant for aquatic ecosystems compared to other stressors, such as chemicals and nutrients. For the case of nuclear electricity investigated, thermal emissions contribute between 3% and over 90% to Ecosystem Quality damage.

Temperature induced disease in the starfish Astropecten jonstoni

In recent years there has been an increasing interest in the effects of water temperature changes on the structure of marine populations. During the 1970s the burrowing starfish Astropecten jonstoni was present in large numbers along the southeast of Sardinia (Italy). When investigations were resumed in 1999 fewer active individuals could be found than in the 1970s, with anecdotal evidence suggesting an increase in sightings of dying animals on the sand surface. These observations, combined with a hitherto unknown susceptibility to handling stress, caused us to investigate the effect of water temperature, salinity and individual size on A. jonstoni survival. Results indicated that significantly fewer starfish were affected by a wasting disease when kept at 12° compared with individuals maintained at 20°C and 25°C regardless of salinity (28 or 35 ppt) and that smaller starfish were less affected. Microbiological analysis revealed that, amongst other species, bacteria of the genus Vibrio, which have been associated with diseases of stressed marine invertebrates, were present in both field and laboratory animals.

Testing the Sensitivity of Phytoplankton Communities to Changes in Water Temperature and Nutrient Load, in a Temperate Lake

Freshwater lakes are biologically sensitive to changes in the surrounding environment and the impacts that such changes have on their water quality are of considerable ecological, recreational and economic importance. In this study the phytoplankton community model, PROTECH, was used to experiment with the effects of elevated temperatures and increased nutrient load on phytoplankton succession and productivity. The response of a phytoplankton community to combined incremental changes in these drivers was analysed, in order to elucidate the resulting ecological changes. Annual mean phytoplankton biomass increased with increases in temperature and nutrient loading, although the latter had the larger effect. The phenology of the dominant phytoplankton taxa changed with increasing water temperature; the three spring blooming species all peaked earlier in the year. The simulated summer bloom of Anabaena became earlier in the year and the Chlorella bloom later. The increased phytoplankton biomass was largely dominated by the cyanobacterium Anabaena, which was especially prevalent during the summer bloom. This resulted in a progressive loss of phytoplankton biodiversity with increasing water temperature and nutrient supply. Model experimentation showed that whilst both factors greatly affected the community, the changes to nutrient loading generally had the greater effect and that at low nutrient levels the effect of water temperature change was reduced considerably. Finally, the model predicted that cyanobacteria have the potential to dominate the phytoplankton community, with clear consequences for water quality, and that this dominance was at its greatest when high water temperatures were combined with high nutrient loads.

Lake phosphorus dynamics and climate warming: A mechanistic model approach

Model results in this work indicate that lakes may respond very differently to climate change depending on their physical character. A physical lake model and a mechanistic phosphorus model are combined with two temperature scenarios generated by a regional climate model (RCM) in three sites in central Sweden—Lake Erken and two basins of Lake Mälaren (Galten and Ekoln). In the phosphorus model water mixing, mineralization, diffusion and biouptake are temperature dependent. In the simulations, Lake Erken is much more sensitive to climate warming than the two basins of Lake Mälaren, and the reason is shown to be the much longer water residence time in Lake Erken (7 years), stressing the importance of internal lake processes. In Galten and Ekoln the water residence times are less than 1 year, and the effects of water temperature changes are small. In Lake Erken the concentration of epilimnetic-dissolved phosphorus is almost doubled in spring and autumn in the warmest climate scenario. Since the lake is mostly phosphorus limited, this means that the potential for phytoplankton production is almost doubled. The implication would be that in Lake Erken, and in other eutrophic lakes with long water residence times, eutrophication problems may become serious in the future, and that managers may need to take action today in order to maintain good water quality in these lakes.

D-2 Application of phase conjugate wave to measurement of fix point displacement on seafloor and effect of water temperature change

D-2 Application of phase conjugate wave to measurement of fix point displacement on seafloor and effect of water temperature change

Filamentous cyanobacteria, temperature and Daphnia growth: the role of fluid mechanics

Viscosity increases significantly with a fall in water temperature, thus temperature change affects not only the metabolic rates of aquatic suspension feeders, but also the physical properties of the surrounding fluid. This mechanistic effect of water temperature change on growth was separated from the effect of metabolism by using culture media with modified viscosity, while the temperature was kept constant. The effect of water viscosity on growth rate and feeding of four Daphnia species (D. magna, D. pulicaria, D. hyalina, D. galeata) was investigated. Increased viscosity decreased the growth rate significantly for three species, with the exception of D. galeata. Changing viscosity also affects growth qualitatively: the filamentous blue-green Cylindrospermopsis raciborskii reduces the growth rate of D. pulicaria at low viscosity, but its negative effect disappears when viscosity is higher. The findings are consistent with the hypothesis that it is the Reynolds number of the filtering appendages that determines the qualitative features of Daphnia filtration. The edibility of C. raciborskii at high water viscosity is most probably caused by lack of interference with filtering combs, and explains the coexistence of D. pulicaria with filamentous blue-green species in the field, and also the observed temperature dependence of growth inhibition of filaments.

Effects of water temperature changes on the endogenous and exogenous rhythms of oxygen consumption in glass eels Anguilla japonica

The oxygen consumption rate (OCR) of glass eels Anguilla japonica was measured to determine the effects of water temperature changes on their endogenous and exogenous rhythms. Glass eels were exposed to different water-temperature patterns during simulated 12, 14 and 24 h cycles. The OCR of wild glass eels, freshly collected from estuaries, exhibited a clear endogenous circatidal rhythm while kept in constant darkness at 15 ± 0.1°C. However, if the temperature was varied, the glass eels OCR coincided with the gradually increasing water temperature (Δt = 1°C per 12 or 24 h) in the experimental chamber. This minor variation in water temperature (Δt = 1°C per 12 or 24 h) was significant enough to affect the rhythmicity of the glass eels' OCR. When the glass eels were exposed to a cyclic increase or decrease in water temperature (1°C per 14 h), the OCR peaks displayed a clear rhythmicity at 14 h intervals. The results indicate that the glass eels' OCR is controlled not only by an endogenous circatidal rhythm, but also by exogenous rhythms related to small environmental changes, such as water temperature changes of as little as 1°C. The possible mechanisms underlying these temperature responses are discussed and the implications of the findings for the eco-physiology and metabolic activity rhythms of glass eels are highlighted.

Factors Affecting the Diurnal Variation of Carbon Dioxide Concentration in Standing Water in a Rice Field.

The carbon dioxide concentration (pCO2) in irrigation water in a rice field was measured from August 9 to 11, 1996. The pCO2 showed low values of a few μatm in the daytime, and high values over 2, 500μatm (=253.3Pa) in the early morning. This large diel change of pCO2 is associated with three factors; water temperature change, gas exchange across air-water interface, and biological consumption of carbon dioxide in water through photosynthesis. The effect of water temperature change results in the modification by 60μatm in pCO2 (2% of the diurnal change) taking into account the diurnal change of water temperature (ca. 6°C). The carbon dioxide exchange across the air-water interface varied from -2.7 to 28.4μgm-2s-1, with a daily mean of 5.5μgm-2s-1, causing a variation of about 609μatm per day (24% of the diurnal change). Dissolved carbon dioxide [CO2] and oxygen [O2] data showed the photosynthetic (respiration) relationship: [CO2]/[O2]=-106/138. This suggests the possibility that the photosynthetic (respiration) activity of algae is responsible for the residual fraction (ca. 73%) of the diurnal change of pCO2. It is also noted that there was a measurable increase in the downward carbon dioxide flux (ca. 0.3mgm-2s-1) from the atmosphere when the paddy field was flooded compared to when it was drained. The increment of the downward carbon dioxide flux was compatible with the carbon dioxide emission rates at the soil surface. The carbon dioxide exchange rates at the water surface were smaller by a factor of 1, 000 compared with fluxes over a rice stand and smaller by a factor of 100 than the carbon dioxide emission rates at the soil surface.

Temperature Effects in Nuclear Magnetic Resonance Spectroscopy

The effect of temperature on the stability of the Varian V-4300–2 NMR spectrometer has been investigated. The spectrometer was most sensitive to changes in room-air temperature. A change of 0.3°C per minute caused a spectrometer drift of about 20 cps per minute. A change of 0.1°C per minute in temperature of magnet cooling water caused a spectrometer drift of 1 cps per minute. Enclosing the magnet served to minimize effects of air temperature changes but amplified the effects of water temperature changes. Satisfactory control was attained by running the refrigeration units continuously and regulating the temperatures by controlling the suction pressure on the evaporators. Under these conditions spectra were reproducible to within ½ cps.