Water temperature induced interannual variation in spawning of Japanese Spanish mackerel Scomberomorus niphonius in the northern Yellow Sea

Japanese Spanish mackerel Scomberomorus niphonius is a pelagic,neritic species that occurs in the Yellow Sea in high commercial value.The spawning period of this fast-growing species is controlled by water temperature.Based on microstructural analysis of otoliths from 145 young-of-the-year(YoY)S.niphonius collected by trawl in 2017,2018,and 2020,and the temporal variation in the spawning period in the northern Yellow Sea,and its relationship to water temperature were examined.We found that the spawning lasted from late April to late June but differed in year:in 2017 it occurred from April 23 to June 1 and peaked in early May,in 2018 it extended later from May 7 to June 29,and in 2020 from May 6 to June 22 and peaked later from late May to mid-June.The highest temperature in 2017 corresponds with the earliest end of the spawning period and a lower growing degree-day(GDD,℃·day)of 383℃·day.In 2018,slower warming corresponds with a longer spawning period,and a GDD spawning period of 506℃·day.Rapid warming in late 2020 corresponds with a spawning peak,and a GDD spawning temperature of 448℃·day.Despite differences in spawning period,the water temperature when spawning commenced was 10-12℃.Therefore,water temperature is the major determinant of the spawning period,affecting both the starting and the ending of spawning.This study improved our understanding of the spawning dynamics and environmental adaptation of S.niphonius,and how these might change in environments subject to increased warming.

Changes of Water Temperature and Harmful Algal Bloom in the Daya Bay in the Northern South China Sea

Economic development around the Daya Bay, China has profoundly affected the marine environment in the bay area in recent years, particularly since the operation of Daya Bay Nuclear Power Station （DNPS） in 1994. This study analyzed the changes of water temperature and harmful algal blooms （HABs） for two periods： 1983-1993 and 1994-2004, using in situ and satellite data. Results showed that yearly mean surface water temperature （SWT） and Chl-a concentration （Chl-a） increased by 1.1 ℃ and 1.9 mg/m^3, respectively, after 1994. The monthly occurrence of HAB was found to have increased also. HABs appeared only in spring and autumn before 1994, but occurred all the year round after 1994. SWT, Chl-a and HABs all increased significantly in May. Those changes were associated with environmental changes in this area, such as thermal discharge from the DNPS and enhancement of eutrophication from human activities around the Daya Bay.

Mechanism of Nutrient Silicon and Water Temperature Influences on Phytoplankton Growth

This paper analyzed how nutrient silicon and water temperature influenced the variation of phytoplankton growth and the change of its assemblage structure, and probed the different characteristics of the variation of phytoplankton growth and the different profiles of the change of its assemblage structure influenced by nutrient silicon and water temperature. Taking Jiaozhou Bay for example, this paper showed the process of both the variation of phytoplankton growth and the change of its assemblage structure, unveiled the mechanism of nutrient silicon and water temperature influencing the variation of phytoplankton growth and the change of its assemblage structure, and determined that nutrient silicon and water temperature were the motive power for the healthy running of the marine ecosystem.

Simulation of water temperature distribution in Fenhe Reservoir

In order to evaluate the need of controlling the temperature of water discharged from the Fenhe Reservoir, the reservoir water temperature distribution was examined. A three-dimensional mathematical model was used to simulate the in-plane and vertical distribution of water temperature. The parameters of the model were calibrated with field data of the temperature distribution in the Fenhe Reservoir. The simulated temperature of discharged water is consistent with the measured data. The difference in temperature between the discharged water and the natural river channel is less than 3 ℃ under the current operating conditions. This will not significantly impact the environment of downstream areas.

Effect of water temperature on digestive enzyme activity and gut mass in sea cucumber Apostichopus japonicus (Selenka),with special reference to aestivation

The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopusjaponicus, including relative gut mass （RGM）, amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28℃ over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21 ℃ and markedly decreased over the whole experiment period at 28℃; however, no significant effect of duration was observed at 7 or 14℃. At 14℃, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28℃. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28℃, lipase activity peaked in 20 days and then markedly decreased to a minimum at the end of the experiment. On the other hand, pepsin activity at 28℃ continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21℃ group and in the previous 20 days in the 28℃ group were in the prophase of aestivation. At 28℃, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion ofA. japonicus is comparatively weak within a specific range of water temperatures and aestivation behavior is accompanied by significant changes in RGM and digestive enzyme activities.

Evaluation of spatial-temporal dynamics in surface water temperature of Qinghai Lake from 2001 to 2010 by using MODIS data

Lake surface water temperature （SWT） is an important indicator of lake state relative to its water chemistry and aquatic ecosystem,in addition to being an important regional climate indicator.However,few literatures involving spatial-temporal changes of lake SWT in the Qinghai-Tibet Plateau,including Qinghai Lake,are available.Our objective is to study the spatial-temporal changes in SWT of Qinghai Lake from 2001 to 2010,using Moderate-resolution Imaging Spectroradiometer （MODIS） data.Based on each pixel,we calculated the temporal SWT variations and long-term trends,compared the spatial patterns of annual average SWT in different years,and mapped and analyzed the seasonal cycles of the spatial patterns of SWT.The results revealed that the differences between the average daily SWT and air temperature during the temperature decreasing phase were relatively larger than those during the temperature increasing phase.The increasing rate of the annual average SWT during the study period was about 0.01℃/a,followed by an increasing rate of about 0.05℃/a in annual average air temperature.The annual average SWT from 2001 to 2010 showed similar spatial patterns,while the SWT spatial changes from January to December demonstrated an interesting seasonal reversion pattern.The high-temperature area transformed stepwise from the south to the north regions and then back to the south region from January to December,whereas the low-temperature area demonstrated a reversed annual cyclical trace.The spatial-temporal patterns of SWTs were shaped by the topography of the lake basin and the distribution of drainages.

Effects of water temperature and dietary carbohydrate levels on growth and energy budget of juvenile Litopenaeus vannamei

A 3×3 factorial experiment was conducted to determine the effects of water temperature (22 ℃, 27℃ and 32℃) and dietary carbohydrate (CBH) levels (15.47%, 29.15% and 41.00%) on growth, food consumption, feed efficiency, apparent digestibility coefficient and energy budget of juvenile Lito- penaeus vannamei. The results showed that, at each dietary CBH level, specific growth rate, food con- sumption and apparent digestibility coefficient generally increased, while feed efficiency decreased with increasing water temperatures. Specific growth rate and food consumption were the highest in the shrimps fed with diet of 29.15% CBH, closely followed by those with 15.47% CBH, and those with 41.00% CBH had the lowest value.

Convolutional Neural Network-Based Identity Recognition Using ECG atDifferent Water Temperatures During Bathing

This study proposes a convolutional neural network(CNN)-based identity recognition scheme using electrocardiogram(ECG)at different water temperatures(WTs)during bathing,aiming to explore the impact of ECG length on the recognition rate.ECG data was collected using non-contact electrodes at five different WTs during bathing.Ten young student subjects(seven men and three women)participated in data collection.Three ECG recordings were collected at each preset bathtub WT for each subject.Each recording is 18 min long,with a sampling rate of 200 Hz.In total,150 ECG recordings and 150 WT recordings were collected.The R peaks were detected based on the processed ECG(baseline wandering eliminated,50-Hz hum removed,ECG smoothing and ECG normalization)and the QRS complex waves were segmented.These segmented waves were then transformed into binary images,which served as the datasets.For each subject,the training,validation,and test data were taken from the first,second,and third ECG recordings,respectively.The number of training and validation images was 84297 and 83734,respectively.In the test stage,the preliminary classification results were obtained using the trained CNN model,and the finer classification results were determined using the majority vote method based on the preliminary results.The validation rate was 98.71%.The recognition rates were 95.00%and 98.00%when the number of test heartbeats was 7 and 17,respectively,for each subject.

Variation in the distribution of wintering anchovy Engraulis japonicus and its relationship with water temperature in the central and southern Yellow Sea

In the present study,we investigated a shift in the spatial distribution of wintering anchovy(Engraulis japonicus)and its relationship with water temperature,using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea,during 2000–2015.Our results indicate that the latitudinal distribution of wintering anchovy varied between years,but there was no consistent pattern in the direction of change(north or south).Wintering anchovy did not move northward with increasing water temperature.However,the latitudinal distribution of wintering anchovy correlated well with 10°C and 11°C isotherms.The results of both a one-step and a two-step generalized additive model indicated that water temperature was associated with both presence and biomass of wintering anchovy.This paper is the fi rst to systematically examine the relationship between anchovy distribution and water temperature using a variety of techniques.All the fi ndings confi rm the impact of water temperature on wintering anchovy distribution,which has important implications for the continued management of the anchovy resource and the enhancement of marine fi shery resources in the Yellow Sea,especially as the climate changes.However water temperature only partly explains the species distribution of anchovy,and stock characteristics also aff ect fi shery distribution.Therefore,other factors should be considered in future research.

New acoustic system for continuous measurement of river discharge and water temperature

In many cases, river discharge is indirectly estimated from water level or streamflow velocity near the water surface. However, these methods have limited applicability. In this study, an innovative system, the fluvial acoustic tomography system （FATS）, was used for continuous discharge measurement. Transducers with a central frequency of 30 kHz were installed diagonally across the river. The system＇s significant functions include accurate measurement of the travel time of the transmission signal using a GPS clock and the attainment of a high signal-to-noise ratio as a result of modulation of the signal by the 10th order M-sequence. In addition, FATS is small and lightweight, and its power consumption is low. Operating in unsteady streamflow, FATS successfully measured the cross-sectional average velocity. The agreement between FATS and acoustic Doppler current profilers （ADCPs） on water discharge was satisfactory. Moreover, the temporal variation of the cross-sectional average temperature deduced from the sound speed of FATS was similar to that measured by a temperature sensor near the bank.

Diurnal Variation in Relative Photosynthetic Performance of Marestail (Hippuris vulgaris Linn.) Across a Water Temperature Gradient using PAM Fluorometry in Jiuzhaigou National Nature Reserve,Sichuan Province,China

This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates （ETRmax） were measured as rapid light curves （RLCs） by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 ~C. Non- photochemical quenching （NPQ） of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield （Fv/Fm） of submerged marestail in Five Colored Lake showed full recovery at 170o h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highestin Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant＇s ecophysiological reactions.

Coseismic effects of water temperature based on digital observation from Tayuan well,Beijing

On the basis of digital records from Tayuan well, we study coseismic effects of water temperature caused by remote earthquakes. The records show that the water temperature changes are consistently following the process of drop-rise-recovery regardless of focal mechanism or epicentral directions. The step amplitude of water temperature increases with the increase of earthquake magnitude, and decreases with the decrease of epicentral distances. They have rather well correlation. Water temperature rising after earthquake is influenced by water level variations. Fi- nally, the mechanisms of coseismic effects of water temperature have been discussed. Preliminary study shows that accelerated convection and mixing of different temperature water in virtue of seismic wave are the main causes of water temperature drops. Seismic wave accelerates water convection, which causes warm water to move up from deeper part of the well and cold water to go down from the upper part. Temperature probe will detect water temperature drops at early stage. After the occurrence of earthquake, as the fluctuation of water level gradually quiets down, water temperature near the probe begins to rise.

Environmental Ecological Response to Increasing Water Temperature in the Daya Bay, Southern China in 1982-2012

The increase of water temperature, due to thermal discharges from two nuclear power stations, was one of the most significant environmental changes since 1982 in the Daya Bay, located in the north of the South China Sea. This study investigates the long-term (1982-2012) environmental changes in Daya Bay in response to the increase of water temperature, via comprehensively interpreting and analyzing both satellite and in situ observations along with previous data. The results show that: 1) salinity, dissolved oxygen (DO), chemical oxygen demand (COD) and nutrients had been enhanced after the thermal discharges started in 1994;2) the concentration of Chl-a increased while the net-phytoplankton abundance decreased;3) diversity of the phytoplankton community had decreased;4) fishery production had declined;and 5) frequency of Harmful Algal Bloom occurrence had increased. Satellite images show clearly that a thermal plume from the power stations extended toward the interior of Daya Bay, and that surface temperature of the seawater increased as one approached the power stations. The analysis suggests that the thermal water discharged from the two power stations was a driver of the ecosystem’s change in Daya Bay. Several factors, including nutrients, salinity, DO, and COD, varied according to the increase of water temperature. These factors affected the water quality, Chl-a, and phytoplankton in the short term and impaired aquatic organisms and the whole ecosystem in the long term.

Numerical Simulation of Coseismic Response and Its Mechanism of Well Water Temperature to Farfield Strong Earthquakes1

Heat flow is inevitably accompanied by temperature change,thus,the water temperature coseismic response during earthquake activity should also obey the laws of thermodynamics.Taking the M S8.0 Wenchuan,Sichuan,China earthquake and the M9.0Tohoku,Japan earthquake as an example,and based on the data of water temperature coseismic responses observed in well ZK26 in Haikou,Hainan Province,China,we investigate the relationship between well water temperature change and heat transfer in the coseismic response process and the relevant thermodynamic mechanism by using the numerical simulation method for thermodynamic equations.Then,through forward modeling,we obtain several simulation curves of water temperature change in response to earthquakes along the well depth at different times.The simulated curves of water temperature change approximately fit the observed curves.Consequently,based on the variation of temperature,we find that the modes of well water temperature coseismic response( ascending,descending or stable) are related to factors such as the location of sensors,distribution and location of heat sources,the span between sensors and heat sources.

Refined Modeling of Water Temperature and Salinity in Coastal Areas

The prediction of water temperature and salinity in coastal areas is one of the essential tasks in water quality control and management. This paper takes a refined forecasting model of water temperature and salinity in coastal areas as a basic target. Based on the Navier-Stokes equation and k-epsilon turbulence model, taking the characteristics of coastal areas into account, a refined model for water temperature and salinity in coastal areas has been developed to simulate the seasonal variations of water temperature and salinity fields in the Hakata Bay, Japan. The model takes into account the effects of a variety of hydrodynamic and meteorological factors on water temperature and salinity. It predicts daily fluctuations in water temperature and salinity at different depths throughout the year. The model has been calibrated well against the data set of historical water temperature and salinity observations in the Hakata Bay, Japan.

Soft-Sensing Method of Water Temperature Measurement for Controlled Cooling System

Aiming at the water temperature measuring problem for controlled cooling system of rolling plant,a new water temperature measuring method based on soft-sensing method with a water temperature model of on-line self correction parameter was built.A water temperature compensation factor model was also built to improve coiling temperature control precision.It was proved that the model meets production requirements.The soft-sensing technique has extensive applications in the field of metal forming.

Effect of water temperature on pulse duration and energy of stimulated Brillouin scattering

The water temperature has a strong effect on the kinematic viscosity, which is inversely proportional to the phonon lifetime and the gain coefficient. The higher the temperature is, the smaller the kinematic viscosity is, and the larger the phonon lifetime is. At a low pump power and a short focal length, we can derive a single-peak stimulated Brillouin scattering （SBS） pulse. The duration of this single-peak SBS pulse depends mainly on the phonon lifetime of water. With the increase of the water temperature, the duration of such a single-peak SBS pulse will become longer, and the SBS energy will become higher for the gain coefficient, which is related to the phonon lifetime. Therefore, varying the medium temperature can lead to the changes of SBS pulse duration and SBS energy.

Effect of Water Temperature on Feeding Rhythm in Common Carp (Cyprinus carpio haematopterus Temminck et Schlegel)

Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.

Test of numerical prediction of sea water temperature in the Taiwan Strait

A dynamic numerical prediction model of sea water temperature for limited sea area is used to predict the sea water temperature at the sea area near Fujian. Essential adjustments have been made in accordance with the characteristics of this region. Two Tests have been made. One is in summer (3 d) and the other is in winter (10 d). In the summer test, a typhoon is just passing by and the calculated current field well responds to typhoon. In the winter test, variation tendency of the predicted sea water temperature field agrees with that of the observation basically, the absolute mean error in the whole sea area is 0 .6 ℃. The variation of the sea water temperature is mostly af- fected by entrainment and pumping, which is related to the topography of the strait.

Analysis of influence of water temperature on milk powder proteins using MALDI-TOF MS

The influence of water temperature on protein composition in the reconstitution of milk powder was evaluated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS）. 11 ion peaks in the matrix-assisted laser desorption/ionization （MALDI） spectra were examined to study the alteration of relative quantities of milk proteins when water at different temperature was employed in the reconstitution of milk powder. A discrepancy factor Dij was implemented to represent the degree of milk proteins＇ denaturation. Data obtained indicated that Dij value increased with rising water temperature, and thermal damage to milk proteins became evidently when the water temperature exceeded 60℃. The results confirmed that nutrient loss occurred when milk proteins denatured in water at high temperatures.