Function Of Water Temperature Research Articles

Estimation of bioluminescence intensity of the dinoflagellates Noctiluca scintillans, Polykrikos kofoidii, and Alexandrium mediterraneum populations in Korean waters using cell abundance and water temperature

Many dinoflagellates produce bioluminescence. To estimate the intensity of bioluminescence produced by populations of the heterotrophic dinoflagellates Noctiluca scintillans and Polykrikos kofoidii and autotrophic dinoflagellate Alexandrium mediterraneum in Korean waters, we measured cellular bioluminescence intensity as a function of water temperature and calculated population bioluminescence intensity with cell abundances and water temperature. The mean 200-second-integrated bioluminescence intensity per cell (BLcell) of N. scintillans satiated with the chlorophyte Dunaliella salina decreased continuously with increasing water temperature from 5 to 25°C. However, the BLcell of P. kofoidii satiated with the mixotrophic dinoflagellate Alexandrium minutum continuously increased from 5 to 15°C but decreased at temperatures exceeding this (to 30°C). Similarly, the BLcell of A. mediterraneum continuously increased from 10 to 20°C but decreased between 20 and 30°C. The difference between highest and lowest BLcell of N. scintillans, P. kofoidii, and A. mediterraneum at the tested water temperatures was 3.5, 11.8, and 21.0 times, respectively, indicating that water temperature clearly affected BLcell. The highest estimated population bioluminescence intensity (BLpopul) of N. scintillans in Korean waters in 1998–2022 was 4.22 × 1013 relative light unit per liter (RLU L-1), which was 1,850 and 554,000 times greater than that of P. kofoidii and A. mediterraneum, respectively. This indicates that N. scintillans populations produced much brighter bioluminescence in Korean waters than the populations of P. kofoidii or A. mediterraneum.

Harmful blooms across a longitudinal gradient in central Europe during heatwave: Cyanobacteria biomass, cyanotoxins, and nutrients

Climate change has increased the frequency, duration and intensity of heatwaves in Europe. These extreme events result in alterations of physical, chemical, and biological properties of lakes that may synergistically promote cyanobacterial dominance. In our study we focused on cyanobacterial blooms in lakes distributed over a longitudinal gradient in Central Europe during one of the “top ten European heat waves” in summer 2015. 92 lakes were included in the study, located across three climatic subregions: cool northern lakes, situated in Lithuania, temperate northern lakes in Poland, and warm northern lakes in Croatia. The objective of the study was to determine if cyanobacterial biomass, predominant species, and cyanotoxin concentration differed, across the south-north gradient, as a function of water temperature, total phosphorus, and total nitrogen. Statistical significance of observed patterns was tested using the Kruskal-Wallis rank sum test and the generalized linear model. We found the lowest average epilimnion temperature, but the highest average cyanobacterial biomass in the northern, ‘cool’ lakes while the highest average temperature with the lowest average cyanobacterial biomass in the southern, ‘warm’ lakes. The concentration of cyanotoxins was also the highest in the ‘cool’ lakes. Total phosphorus and total nitrogen correlated significantly with cyanobacterial biomass, cyanotoxins concentration and biomass of some cyanobacterial species (mainly Planktothrix agardhii), regardless of the latitude. Only in the ‘cool’ lakes concentration of cyanotoxins (microcystins and anatoxin-a) correlated significantly with cyanobacterial biomass and the biomass of some dominant cyanobacterial species (P. agardhii). Our results emphasized the differences of heat weaves impact on lakes of various latitudes, with the strongest increase in toxic cyanobacterial blooms in northern ‘cool’ lakes, situated in high latitudes. On the other hand, nutrients directly enhanced blooms across all the studied latitudes of Central Europe. The cyanobacteria species dominating in blooms might be recognized as ecological indicators of climate change, especially in the north-eastern part of Europe.

Experimental and Theoretical Investigation of Single-Slope Passive Solar Still with Phase-Change Materials

Many attempts are made worldwide to create cheap, efficient, and eco-friendly water desalination systems. Passive solar stills (SS) are considered to be such. This paper presents the results of the experimental and theoretical investigation of the effects of using phase-change materials (PCM) on the performance of SS. The experiments were conducted for two paraffin waxes, as PCM and 1.0, 2.5, and 5.0 kg of PCM were used. The results of the experimental studies were used to validate a mathematical model, which was based on the energy balance ordinary differential equations. The equations were solved numerically since the approximate solutions obtained numerically are sufficient and relatively simple as compared to the exact analytical solutions. A theoretical analysis was then carried out and a novel and detailed dependence on the water evaporation rate as a function of water temperature and the difference between water and cover temperature was determined. It was also found that the productivity of the SS with PCM strongly depends on the operating conditions. For uniform initial temperatures of the SS, its productivity decreases with an increasing PCM-to-water mass ratio, and the maximum decrease is 10.8%. If the SS is not thermally insulated, the PCM can take the role of a thermal insulator and increase productivity by 1.1%, but there is an optimal PCM-to-water mass ratio. The greatest increase in productivity, by up to 47.1%, can be obtained when the PCM is heated outside the SS and inserted into the SS when the water temperature starts to decrease. In this case, the productivity increases with the increasing PCM-to-water mass ratio. These outcomes fill a knowledge gap caused by a lack of justification for why in some cases, the application of PCM fails to improve the productivity of SS.

Waterborne virus transport and the associated risks in a large lake

Waterborne enteric viruses in lakes, especially at recreational water sites, may have a negative impact on human health. However, their fate and transport in lakes are poorly understood. In this study, we propose a coupled water quality and quantitative microbial risk assessment (QMRA) model to study the transport, fate and infection risk of four common waterborne viruses (adenovirus, enterovirus, norovirus and rotavirus), using Lake Geneva as a study site. The measured virus load in raw sewage entering the lake was used as the source term in the water quality simulations for a hypothetical scenario of discharging raw wastewater at the lake surface. After discharge into the lake, virus inactivation was modeled as a function of water temperature and solar irradiance that varied both spatially and temporally during transport throughout the lake. Finally, the probability of infection, while swimming at a popular beach, was quantified and compared among the four viruses. Norovirus was found to be the most abundant virus that causes an infection probability that is at least 10 times greater than the other viruses studied. Furthermore, environmental inactivation was found to be an essential determinant in the infection risks posed by viruses to recreational water users. We determined that infection risks by enterovirus and rotavirus could be up to 1000 times lower when virus inactivation by environmental stressors was accounted for compared with the scenarios considering hydrodynamic transport only. Finally, the model highlighted the role of the wind field in conveying the contamination plume and hence in determining infection probability. Our simulations revealed that for beaches located west of the sewage discharge, the infection probability under eastward wind was 43% lower than that under westward wind conditions. This study highlights the potential of combining water quality simulation and virus-specific risk assessment for a safe water resources usage and management.

Air-water interactions regulating water temperature of lakes: Direct observations (Agamon Hula, Israel) and analytical solutions

Air-water interactions regulate lake-water temperature by balancing the rate of change of water temperature (stored heat) with the incoming and outgoing heat fluxes, which are functions of water temperature and external forcing. Yet, there is a large knowledge gap in quantifying the thermoregulation of a lake, and especially managed lakes, which is hypothesized to be related to both external environmental forcing and management decisions on lake depth and water inflow. Here we explore the thermoregulation of a restored and managed Mediterranean lake (Agamon Hula, Israel), by direct measurements of all major heat fluxes. We interpret the results with a rigorous analysis of the thermoregulation equation, obtained by formulating the energy balance equation in terms of water temperature. The equation shows how water temperature of a lake shifts toward steady state, scaled by the lake’s response time. Where the steady-state temperature was reached, it was controlled by external environmental forcing and not by lake depth. Whereas the thermal response time to re-attain steady state, following an abrupt change in various environmental conditions, is controlled by water depth. The lake-temperature response to pre-defined oscillations of the environmental forcing showed that the amplitude of water temperature fluctuations and the time delay from steady-state are controlled by the ratio between the environmental forcing’s time period (diurnal, seasonal or other cycles) and the thermal response time of the lake. The summertime measured CO2 fluxes of Agamon Hula revealed the lake acts as a CO2 source to the atmosphere, overpassing similar water bodies from different climates.

RETRACTED: Globally, Freshwater Ecosystems Emit More CO2 Than the Burning of Fossil Fuels

Freshwater emits substantial volumes of CO2 to the atmosphere. This has largely gone unnoticed in global carbon budgets. My aim was to quantify the CO2 emanating from freshwater from 66° N to 47° S latitudes via in situ bacterial respiration (BR). I determined BR (n = 326) as a function of water temperature. Freshwater is emitting CO2 at a rate of 58.5 Pg C y−1 (six times that of fossil fuel burning). Most is emitted from the Northern Hemisphere. This is because the high northern summer temperatures coincide with most of the world’s freshwater. Diffuse DOC sources, for example dust, may be driving high freshwater BR. However, many sources remain elusive and not individually quantified in the literature. We must include freshwater CO2 emissions in climate models. Identifying, quantifying and managing freshwater’s diffuse sources of Dissolved Organic Carbon (DOC) will hopefully provide us with another opportunity to change our current climate trajectory.

Aqualuz: a new solar disinfection device for treatment of cistern water

Abstract We conducted field, laboratory and modeling studies to evaluate the efficiency of a new solar disinfection (SODIS) device called Aqualuz for the removal of Escherichia coli (EC) from cistern water in the Brazilian semiarid, for different solar exposure–water temperature conditions. The results indicated EC contamination (100–300 MPN/100 mL) in all tests performed. As compared to the literature, lower exposure times (2.5–4.0 h) and solar radiations (250–410 W/m²) were sufficient for EC elimination. Then, assuming the complete-mix approach and first-order kinetics, it was possible to adjust EC decay rate constants (k) considering three different models: constant k-value, k as a function of water temperature and a new formulation for k as a function of both solar radiation and water temperature. All models performed well with normalized root mean squared logarithmic error (NRMSLE) lower than 20%, but the best fitting was obtained with the new approach. A new relationship between solar radiation and water temperature was also obtained, which allowed model simulations of EC decay for 34 municipalities in the Brazilian northeast, resulting in a color map for the region depicting the exposure periods of 1.8–5.6 h for reaching a 3-log reduction.

Multimedia distributions and the fate of microcystins from freshwater discharge in the Geum River Estuary, South Korea: Applicability of POCIS for monitoring of microalgal biotoxins

Here, we investigated the characteristics of the environmental multimedia distribution of microcystins (MCs) introduced from freshwater discharge through the estuary dam of the Geum River. In addition, the applicability of a passive sampling device (polar organic chemical integrative sampler, POCIS) for monitoring MCs was evaluated. Surface water, suspended solids (SS), sediments, and oysters were collected from the inner and outer estuary dam. Seven MC variants were analyzed using HPLC-MS/MS. POCIS was deployed at three sites over one week, and MCs were monitored for four weeks from August to September 2019. Before POCIS was deployed in the field, compounds-specific sampling rates of MCs were determined as functions of water temperature (10, 20, and 30 °C), flow rate (0, 0.38, and 0.76 m s−1), and salinity (0, 15, and 30 psu) in the laboratory. The sampling rates of MCs in POCIS increased significantly with increasing water temperature and flow rate, whereas salinity did not significantly affect the sampling rates between freshwater and saltwater. The MCs in the Geum River Estuary mainly existed as particulate forms (mean: 78%), with relatively low proportions of dissolved forms (mean: 22%), indicating that MCs were mainly contained in cyanobacterial cells. There was no significant correlation among the concentrations of MCs in water, SS, sediments, and oysters. Time-weighted average concentrations of MCs from POCIS were not significantly correlated with the concentrations of MCs in water and oysters. The metabolites of MCs, including MC-LR-GSH, MC-LR-Cys, MC-RR-GSH, and MC-RR-Cys, were detected in oysters (no metabolites were detected in POCIS). Overall, POCIS can be useful for monitoring dissolved MCs in the aquatic ecosystem, particularly in calculating time-weighted average concentrations, but it seems to have limitations in evaluating the contamination status of total MCs, mainly in particulate form.

The influence of microbial mats on travertine precipitation in active hydrothermal systems (Central Italy)

AbstractThe study of hydrothermal travertines contributes to the understanding of the interaction between physico‐chemical processes and microbial mats in carbonate precipitation. Three active travertine sites were investigated in Central Italy to characterise the types of carbonate precipitates and the associated microbial mats at varying physico‐chemical parameters. Carbonate precipitated fabrics at the decimetre to millimetre‐scale and microbial mat composition vary with decreasing water temperature: (a) at relatively higher temperature (55–44°C) calcite and aragonite crystals precipitate on microbial mats of Chloroflexi and sulphur‐oxidizing microbes forming filamentous streamer fabrics with sparse cyanobacteria, (b) at intermediate temperature (44–40°C), rafts, coated gas bubbles and dendrites are associated with Spirulina cyanobacteria and other filamentous and rod‐shaped cyanobacteria, (c) low temperature (34–33°C) laminated crusts and oncoids forming in a terraced slope system are associated with diverse Oscillatoriales and Nostocales filamentous cyanobacteria, Spirulina and diatoms. At the microscale, carbonate precipitates are similar in the three sites consisting of prismatic calcite crystals organised in radial rosettes or fibrous aragonite spherulites (40–300 µm in diameter), overlying or embedded in Extracellular Polymeric Substances. Clotted peloidal micrite dominates at temperatures <40°C, also encrusting filamentous microbes. Carbonates are associated with gypsum crystals; extracellular polymeric substances are enriched in silicon, aluminium, magnesium, calcium, phosphorous and sulphur; authigenic aluminium‐silicates form aggregates on Extracellular Polymeric Substances. This study confirms that microbial communities in hydrothermal settings vary as a function of water temperature. Carbonate precipitates at the microscale are similar in the three settings, despite different microbial communities, suggesting that travertine precipitation, driven by carbon dioxide degassing, is influenced by biofilm extracellular polymeric substances acting as a substrate for crystal nucleation (Extracellular Polymeric Substances‐mediated mineralization) and affecting the resultant fabric types, independently from specific microbial community composition and metabolism.

An assessment Indonesia’s Ocean Thermal Energy Conversion (OTEC) as an electrical energy resource

The primary source of Indonesian electricity still has a dependence on the availability of fossil energy, which is limited in its presence and has non-renewable properties. It is necessary for alternative energy research as a renewable source of electrical power to replace energy sources that cannot be renewed. The one of energy is ocean thermal energy conversion, in which the technology is based on the thermal energy difference between surface temperatures and deepsea water to produce electricity. The research aimed to assess the power potential generated by utilizing the vertical sea temperature in some Indonesian waters. The survey method was used to collect secondary data from the HYbrid Coordinate Ocean Model. The process was completed with the conversion of OTEC to produce the electric base on the model applied by Rauchenstein. This model calculated the net power production of an OTEC plant as a function of water temperature and chilled water pipe length with the potential OTEC power generated for a closed cycle power plant of 100 MW / 150 MW gross power. The study found an average temperature difference of 20 °C at a depth of ≥500 m. Based on the seasonally mean, the highest potential of power was in the Papua of 174 MW during transitional season 2. The lowest value was assessed in Southeast Sulawesi of 82.09 MW in the southeast season. The highest electricity potential for annual average has been obtained in Papua with 168.33 MW and the lowest around 97.69 MW in North Sulawesi.

Unravelling the hydrological effects on spatiotemporal variability of water chemistry in mountainous rivers from Southwest China

AbstractUnderstanding the effects of hydrological processes on solute dynamics is critical to interpret biogeochemical processes. Water chemistry and isotopic compositions of surface water (δ18Ow and δDw) were investigated in rivers from Southwest China to study the effects of hydrological variability on biogeochemical processes. The inverse relationship between deuterium excess (d‐excess) and δ18Ow could be ascribed to non‐equilibrium fractionation processes, and the slope of the Local River Water Line was much lower than the Local Meteoric Water Line, suggesting the post‐precipitation evaporation pattern. The evaporation fraction (1–f) was estimated by the d‐excess method, varying from 0.01 to 0.18. (1–f), was a function of water temperature and drainage mean elevation, indicating that evaporation easily occurs at high temperatures in low‐elevation regions. The hydrological processes co‐varied with solute dynamics in the river network, and fluid transit time and temperature were likely responsible for the co‐variations. Also, we found that hydrological processes played an important role in solute dynamics through shifting the geochemical processes (e.g., enrichment, water‐rock reaction, photosynthesis, and secondary mineral precipitation). This study highlights that biogeochemical processes co‐vary with hydrological processes, and we suggest that investigating hydrological processes can help to understand biogeochemical processes.

Underwater Wireless Sensor Networks: Estimation of Acoustic Channel in Shallow Water

Underwater sensor networks (UWSN) include a large number of devices and sensors which are positioned in a specific area to carry out monitoring in cooperation with each other as well as data collection. In this paper it has been studied and simulated the performance of an extremely important parameter for communication in UWSN such as the acoustic channel capacity as function of water temperature and salinity arise. The performance’s knowledge on acoustic channel may be improved with a deep study of its dependence by season, weather conditions or environmental parameters variation. If an accurate estimation of the acoustic communication capacity utilization for a given area is required, we must consider also the bottom materials of this area. The simulation results presented in this study through an improved algorithm, will help to understand better the underwater acoustic channel performance as a function of all these factors. This is of particular importance for acoustic modems designing, in order to implement suitable functionalities able to adapt the data transmission capacity of the acoustic link to the structure of the oceanic bottom and its component material.

Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction.

The role of roasting in cold brew coffee chemistry is poorly understood. The brewing temperature influences extraction processes and may have varying effects across the roast spectrum. To understand the relationship between brew temperature and roast temperature, hot and cold brew coffees were prepared from Arabica Columbian coffee beans roasted to light, medium, and dark levels. Chemical and physical parameters were measured to investigate the relationships among degree of roast, water temperature, and key characteristics of resulting coffees. Cold brew coffees showed differential extraction marked by decreased acidity, lower concentration of browned compounds, and fewer TDS indicating that cold water brewing extracts some compounds less effectively than hot water brewing. Compounds in coffee did exhibit sensitivity to degree of roast, with darker roasts resulting in decreased concentrations for both hot and cold brew coffees. Total antioxidant capacity (TAC) was only sensitive to degree of roast in cold brew coffees, while hot brew coffees had a constant TAC for all three roast levels. This indicates that the solid bean matrix and its chemical constituents interact with cold water differently than with hot water. Surface wetting, pore dynamics, and solubility all contribute to the extraction potential during brewing and are all functions of water temperature.

Traveling to thermal refuges during stressful temperatures leads to foraging constraints in a central-place forager

AbstractCentral-place foragers can be constrained by the distance between habitats. When an organism relies on a central place for thermal refuge, the distance to food resources can potentially constrain foraging behavior. We investigated the effect of distance between thermal refuges and forage patches of the cold-intolerant marine mammal, the Florida manatee (Trichechus manatus latirostris), on foraging duration. We tested the alternative hypotheses of time minimization and energy maximization as a response to distance between habitats. We also determined if manatees mitigate foraging constraints with increased visits to closer thermal refuges. We used hidden Markov models to assign discrete behaviors from movement parameters as a function of water temperature and assessed the influence of distance on foraging duration in water temperatures above (> 20°C) and below (≤ 20°C) the lower critical limit of the thermoneutral zone of manatees. We found that with increased distance, manatees decreased foraging duration in cold water temperature and increased foraging duration in warmer temperatures. We also found that manatees returned to closer thermal refuges more often. Our results suggest that the spatial relationship of thermal and forage habitats can impact behavioral decisions regarding foraging. Addressing foraging behavior questions while considering thermoregulatory behavior implicates the importance of understanding changing environments on animal behavior, particularly in the face of current global change.

Using meta-analysis to derive a respiration model for Atlantic salmon (Salmo salar) to assess bioenergetics requirements of juveniles in two Canadian rivers

Standard metabolic rates (SMRs) for Atlantic salmon (Salmo salar) have been calculated independently for different life stages and populations, but the absence of a comprehensive SMR model limits its application for modelling the energy use or life stage-specific growth. Atlantic salmon respiration data were compiled from a meta-analysis of 26 publications, and exponential or optimal relationships were fitted to the metadata to estimate respiration equation parameters and generate confidence intervals dependent on temperature and body mass. While model parameters were significant for both models, mass-corrected standard metabolic rates (g O2·day−1) increased as a function of water temperature (°C) and decreased beyond ∼16 °C following an optimal relationship (AICoptimal= –9185.50 versus AICexponential= –8948.95; ΔAIC = 236.55). Juvenile Atlantic salmon growth (cohorts 1 and 2) from bioenergetics simulations did not vary between Little Southwest Miramichi and Northwest Miramichi rivers; however, variation between simulations using the different respiration models (i.e., exponential versus optimal) led to differences in the way fish allocate energy throughout the year. Results from this analysis will inform conservation efforts for the species throughout its current range and predict the energetic requirements at juvenile life stages.

Measurement of temperature dependent absorption coefficient of water at 1064nm wavelength

Measurements of the water absorption coefficient at a laser wavelength of 1064 nm are reported as a function of water temperature. A low power laser beam was used as the probe. The measurement net procedure took into consideration the absorption of the cuvette, while it included detection of bubble formation on the walls of the measurement cuvette and in the water volume. The measurements indicate that the absorption coefficient of water slightly increases in the range of temperatures below 40 °C, reaches maximum and then significantly decreases in the range of temperatures 40 °C – 70 °C. The significant decrease of the temperature dependence of the absorption coefficient supports the supposition that a high transparency of water can be achieved.

Estimation and impact of carbon dioxide capture on drinking water: Tillmans equilibrium diagram

Abstract The increase of CO2 in the atmosphere may produce some effects on drinking water because water tends to naturally capture CO2 species. The main purpose was the study of the impact of capture of free CO2 and its transformation to carbonic acid (H2CO3) and bicarbonate ions (HCO−3). The study used a Tillmans equilibrium diagram obtained from the modified Mojmir Mach model as a function of water temperature and considered the effects on anion and cation composition. Three wells located in different zones were selected, with similar characteristics (capture of CO2). Samples were taken in different seasons of the year and the amount of CO2 in the drinking water was calculated. It was found that with increasing concentrations of free CO2 the pH decreases, and this process makes the water acid and susceptible to dissolve some elements (Ca, Na, K, Si) and other species (HCO−3). The capture of CO2 has important effects on the anion and cation composition of drinking water and on the variation of pH by more than one unit, which may affect the health of consumers. The method presented in this study is an excellent user-friendly alternative to determine the impact of natural capture of total CO2 by water.

Entropy generation analysis and thermal characteristics of radiation heating system

This article presents the developed methodology for the numerical simulation of radiation heat transfer from water panel heaters and optimization results of water temperature in the supply pipeline from the mass flow rate of the heat-carrier and the surface area for a given thermal power of the panel system. A numerical mathematical model is developed in the assumption that heat transfer occurs by means of radiation heat exchange by longitudinal ribs and pipes, which are thermally insulated on top. It is assumed that the temperature of the rib base is equal to the temperature of the outer wall of the pipe. The irregularity of the radiation density in different directions depends on the angle and distance to the irradiated area. The aim of the work is to develop a methodology to simulate the heat transfer processes of a radiation panel water heating system and optimization of design and operating parameters. The radiation intensity is determined by a numerical method using the MATLsoftware package. Our results of experimental studies of the radiation flux density are presented and compared with the results of numerical ones. The thermodynamic efficiency of a panel heating system is analyzed using the entropy production method (exergy destruction). The multicriteria optimization of water temperature in the supply pipeline is performed by LP?-search. It is found that the unevenness of surface temperature of panels reaches 24.4% as well as for the panels of about 50m in length a decrease in water temperature to 20K is observed, which leads to the unevenness of radiation flux density over the heated area. The area of the cooling system as a function of water temperature and the conditions under which the entropy production in the system is minimal is determined.

Submerged attached-growth reactors as lagoon retrofits for cold-weather ammonia removal: performance and sizing.

Small towns that operate wastewater treatment lagoons struggle to meet ammonia limits in cold weather. Here we report the performance of a lagoon, retrofitted with submerged attached growth reactors (SAGRsTM), to provide insight on ammonia effluent compliance and optimal SAGR sizing as functions of water temperature. The lagoon-SAGR water resource recovery facility (WRRF) removed 95% of incoming ammonia with 94% attributed to the SAGRs. The high treatment capacity of the two primary SAGRs, evidenced by nearly continuous dissolved oxygen saturation and exceedingly high ammonia removals, suggested the two secondary SAGRs were essentially unnecessary and that all four SAGRs should be reduced in size. Furthermore, without the secondary SAGRs, the primary SAGR effluent would have exceeded the permitted ammonia discharge limit only four times in the 2.5-year study. At its current size, the lagoon-SAGR WRRF never exceeded permitted ammonia limits, but size reductions should be used for future retrofits.

High temperature accelerates growth of aerobic anoxygenic phototrophic bacteria in seawater.

Temperature is an important controlling factor in the growth activity of all microorganisms. Aerobic anoxygenic phototrophic (AAP) bacteria actively grow in the ocean and are known as one of the main driving forces in organic matter cycling in surface seawater environments. Whether temperature change affects AAP bacteria activity from an ecological viewpoint remains an open question. To date, no known studies have reported the effect of temperature change on AAP bacteria growth in the ocean. We here show that the growth rate of AAP bacteria exceeded that of other bacterial types at high water temperatures in the absence of grazers. The slope of the regression line of the net growth rate of AAP bacteria as a function of water temperature was the same as that for non‐AAP bacteria at all temperatures (10, 20, and 30°C); however, when grazers were eliminated, it was 4.7 times higher than that of non‐AAP bacteria. This result suggests that AAP bacteria are more responsive to water temperature increases than other bacteria and that AAP bacteria might become more dominant than other bacteria under elevated water temperatures.