Thermal Regime Research Articles

Climate induced declines in maternal size may come at a cost to embryonic investment and larval performance in the American lobster

Many crustacean taxa mature at a smaller size in warmer thermal regimes. Over the past four decades, female lobsters American lobster (Homarus americanus) in the rapidly warming Gulf of Maine have also been reported to be maturing at significantly smaller sizes over time. Smaller females have lower fecundity, but whether they also produce lower quality eggs and larvae has been unclear. Here we examine the hypothesis that smaller females invest less energy per larva than larger females, thereby compromising post-hatch performance and survival. This study used a combination of laboratory and field studies to assess the maternal size effect on embryos and larvae. In a space-for-time comparison of lobsters from contrasting thermal regimes along the coast of New England, we also investigated how lobster collected from populations in cooler northern regions may respond to future warming. We found smaller females not only are less fecund, but their embryos are smaller and generally less well invested with lipids than those from larger females. Furthermore, stage I larvae from smaller females are smaller and have less energy reserves needed to survive starvation. Our geographic comparison also revealed that female lobsters living in the warmer thermal regime of southern New England are more fecund and produced larger eggs than females of the same size from colder regimes in the Gulf of Maine, and we cautiously interpret this novel finding as evidence of a counter-gradient adaptation that could compensate for smaller maturation size at lower latitudes, a phenomenon requiring further investigation. These results help to reveal the cascading effects warming can have on important reproductive and larval survival traits on an economically important species.

Duoculture diminishes social interaction costs and improves growth rates of two fish species at different temperatures.

Duoculture has been reported to increase growth rates of some fishes when reared in combination, due to "shading" effects between the species. Two experiments, one involving outdoor cage-rearing in a reservoir, and the other, indoor tank-rearing, were conducted within each of three temperatures ranges (means of ~18.0°C, ~22.0°C and ~26.5°C), to determine whether duoculture of bluegill (BG) Lepomis macrochirus and yellow perch (YP) Perca flavescens would lead to improved growth relative to when the two species were reared separately. Juvenile bluegill and yellow perch were reared in triplicated groups each involving monoculture sets of 100% BG and 100% YP, and a duoculture set of 50% BG + 50% YP. Experiments in cages (Exp. 1) ran for 150 days while those in tanks ran for 126 days (Exp. 2). In Experiment 1, bluegill exhibited significantly greater (P<0.05) mean weight (P<0.05) in duoculture than in monoculture, under the high summer-like range of temperature (~26.5°C) over most of the experiment, whereas yellow perch showed no significant difference in mean weight in duoculture versus monoculture. By the end of a 150-d experiment, bluegill in duoculture outweighed those in monoculture by 62.5%. In Experiment 2, yellow perch in duoculture grew significantly larger than in monoculture (P<0.05) under the warm thermal regime (mean of ~22°C), while no significant differences were detected in mean weight of bluegill in monoculture versus duoculture. Yellow perch in duoculture outweighed those in monoculture by 33.1% at the end of the experiment. Yellow perch performed better in duoculture than in monoculture under the low thermal regime (mean of ~18°C) in both experiments. A significantly greater reduction of CVwt was observed for both bluegill and yellow perch in duoculture than in monoculture in Experiment 1, while no differences in CVwt reduction were detected for bluegill in Experiment 2. Feed conversion ratios (FCR) of bluegill and yellow perch reared in duoculture were significantly lower than for both fishes reared in monoculture in Experiment 1, while there were no significant differences in FCR among the three groups throughout most of Experiment 2. Findings indicate that duoculture of yellow perch and bluegill holds good potential to improve growth and FCR, and to reduce size variation by diminishing social interaction costs.

Impacts of wildfires on boreal forest ecosystem carbon dynamics from 1986 to 2020

Wildfires significantly change boreal forest ecosystem carbon balance through both direct combustion and post-fire carbon dynamics. Affected vegetation influences soil thermal regime and carbon cycling by impacting the surface energy balance of boreal forests. This study uses a process-based biogeochemistry model to quantify carbon budget of North American boreal forests during 1986–2020 based on satellite-derived burn severity data. During the study period, burn severity generally increases. Fires remove ecosystem carbon of 2.4 Pg C and reduce net ecosystem production (NEP) from 32.6 to 0.8 Tg C yr−1, making the forest ecosystems lose 3.5 Pg C, shifting a carbon sink to a source. The canopy’s cooling effect leads to lower soil temperature and lower net primary production due to lower nitrogen mineralization and uptake. Post-fire NEP decreases from 1.6 to 0.8 Tg C yr−1. This reduction accounts for 50% of the simulated NEP when the effects of fire-affected canopy are not considered. Our study highlights the importance of wildfires and their induced-canopy changes in soil thermal and ecosystem carbon dynamics of boreal forests.

Building a carbon dioxide storage portfolio for the Barrow-Dampier sub-basins through regional screening – an integrated geoscience approach

Safe geological carbon dioxide (CO2) storage (GCS) requires rocks with suitable injectivity, capacity and sealing properties to ensure secure long-term containment of injected CO2. A regional understanding of the subsurface is essential to determine the potential for GCS of a basin and to select target sites. This is best addressed by integrating the basin’s tectono-stratigraphic evolution, its gross depositional environment, and its hydrodynamic, thermal and stress regimes. A basin-scale GCS assessment for the Barrow-Dampier sub-basins was conducted by Geoscience Australia and SLB. The objective of the study is to high-grade geological intervals and sites for potential GCS and to understand potential storage capacity and key risk factors. Stratigraphic and structural mapping of key storage intervals was performed using the reprocessed seismic volume and well database associated with the project. Analysis of critically stressed faults was used to estimate the likelihood of reactivation based on the far-field regional stress field and fault mechanical properties. Pressure, temperature, porosity, permeability, and water geochemistry data have been screened for &gt;500 wells for assessing the storage unit intervals and predicting the hydrodynamic regime. Calibrated 2D basin models provide information on the regional pressure-temperature regime, porosity/permeability distribution, and sealing effectiveness. Potentiometric surface maps for the aquifer systems inform the distribution of potential CO2 plume migration. Results of this integrated regional basin study are used to quantify the risk of identified storage containers and to map the chance of success for GCS at a regional scale. The project results are publicly available via NOPIMS.

Germination attributes of metsulfuron-resistant and metsulfuron-susceptible tropical ageratum (Ageratum conyzoides) populations under various environmental conditions

Abstract Tropical ageratum (Ageratum conyzoides L.) is a problematic weed frequently observed in association with commercially important crops in Australian agroecosystems. Knowledge of the germination response of A. conyzoides is crucial for proactively managing this weed species, especially when herbicide resistance is involved. Herbicide screening and metsulfuron dose-response experiments were conducted on two separate populations of A. conyzoides (referred to as Sugarcane and Roadside) in an open environment to identify a metsulfuron-resistant population. Based on the survival percentage in the metsulfuron dose-response experiment, the Sugarcane population was found to be 54 times more resistant compared to the metsulfuron-susceptible population (referred to as Roadside). Subsequent laboratory experiments were performed to investigate the differential germination response of the two populations. No germination or emergence difference was observed between the Sugarcane and Roadside populations under various thermal regimes (15/5 to 35/25 C with a 12/12-hour photoperiod), salinity levels (0 to 320 mM), osmotic potentials (0 to -1.6 MPa), and burial depths (1 to 4 cm). However, different environmental conditions significantly impacted the germination and emergence of A. conyzoides. Ageratum conyzoides germinated over a wide range of temperatures, with the highest germination rate (&gt;90%) occurring at 30/20 C. With increasing levels of salinity, osmotic potential, and burial depth, the germination/emergence of A. conyzoides declined and was completely inhibited at 300 mM salinity, -0.8 MPa osmotic potential, and a 1 cm burial depth. The data generated from this study will be useful in developing a model-based approach to predict the occurrence of this weed species and thus aid in designing ecologically sustainable integrated weed management protocols.

Extensive palaeo-surfaces beneath the Evans–Rutford region of the West Antarctic Ice Sheet control modern and past ice flow

Abstract. The subglacial landscape of Antarctica records and influences the behaviour of its overlying ice sheet. However, in many places, the evolution of the landscape and its control on ice sheet behaviour have not been investigated in detail. Using recently released radio-echo sounding data, we investigate the subglacial landscape of the Evans–Rutford region of West Antarctica. Following quantitative analysis of the landscape morphology under ice-loaded and ice-unloaded conditions, we identify 10 flat surfaces distributed across the region. Across these 10 surfaces, we identify two distinct populations based on clustering of elevations, which potentially represent remnants of regionally coherent pre-glacial surfaces underlying the West Antarctic Ice Sheet (WAIS). The surfaces are bounded by deeply incised glacial troughs, some of which have potential tectonic controls. We assess two hypotheses for the evolution of the regional landscape: (1) passive-margin evolution associated with the break-up of the Gondwana supercontinent or (2) an extensive planation surface that may have been uplifted in association with either the West Antarctic Rift System or cessation of subduction at the base of the Antarctic Peninsula. We suggest that passive-margin evolution is the most likely of these two mechanisms, with the erosion of glacial troughs adjacent to, and incising, the flat surfaces likely having coincided with the growth of the WAIS. These flat surfaces also demonstrate similarities to other identified surfaces, indicating that a similar formational process may have been acting more widely around the Weddell Sea embayment. The subsequent fluctuations of ice flow, basal thermal regime, and erosion patterns of the WAIS are therefore controlled by the regional tectonic structures.

Effect of Different Thermal Regimes and Moisture Levels on the Growth Parameters of Wheat (Triticum aestivum L.) Crop Grown under Agro-climatic Conditions of Eastern Uttar Pradesh, India

Effect of Different Thermal Regimes and Moisture Levels on the Growth Parameters of Wheat (Triticum aestivum L.) Crop Grown under Agro-climatic Conditions of Eastern Uttar Pradesh, India

Effect of sowing management and herbicides application on weeds and yield of berseem (Trifolium alexandrinum)

A field experiment was conducted during winter (rabi) seasons of 2020–2021 and 2021–2022 at research farm of College of Agriculture, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh to study the impact of planting time and herbicides application on weeds and berseem (Trifolium alexandrinum L.) yield. Experiment was conducted in a split plot design with 20 treatments comprising of 4 dates of sowing, viz. October 15th, October 30th, November 15th and November 30th in main plots and these were superimposed with 5 weed control treatments i.e. Pyroxasulfone 125 g/ha as pre emergence; Pyroxasulfone 125 g/ha at 14 DAS; Oxyfluorfen 100 g/ ha + Imazethapyr 15 g/ha after first cutting; Oxyfluorfen 100 g/ha + Imazethapyr 15 g/ha after first and second cutting, replicated thrice. Berseem variety JB 05-9 was sown in the experimental field with recommended package of practices. There was predominance of dicot weeds as compared to monocot in berseem at Jabalpur, Madhya Pradesh. Among the dicot weeds, Medicago truncatula Gaertn. (37.48%) and Cichorium intybus (L.) (27.74%) were predominant. However, other weeds like Cyperus rotundus (L.) (13.79%), Anagallis arvensis (L.) (11.21%) and Chenopodium album (L.) (9.78%) were also present in good numbers. Sowing of berseem in the thermal regimes of 15th October and application of Oxyfluorfen 100 g/ha + Imazethapyr 15 g/ha after first and second cutting was most effective treatment for curbing the growth of weeds as it attained the minimum density and dry weight of weeds during both the years. However, sowing of 15th October with application of Oxyfluorfen 100 g/ha + Imazethapyr 15 g/ha after first cutting recorded the superior values of growth parameters, yield attributing traits, green fodder yield, dry matter yield and seed yield and found more remunerative as it fetched the higher NMR and B:C ratio as compared to other combinations.

Latitudinal variation in thermal performance of the common coral, Pocillopora spp.

Understanding how tropical corals respond to temperatures is important to evaluating their capacity to persist in a warmer future. We studied the common Pacific coral Pocillopora over 44° of latitude, and used populations at three islands with different thermal regimes to compare their responses to temperature using thermal performance curves (TPCs) for respiration and gross photosynthesis. Corals were sampled in the local autumn from Moorea, Guam, and Okinawa where mean (± s.d.) annual seawater temperature is 28.0±0.9°C, 28.9±0.7°C, and 25.1±3.4°C, respectively. TPCs for respiration were similar among latitudes, the thermal optimum (Topt) was above the local maximum temperature at all three islands, and maximum respiration was lowest at Okinawa. TPCs for gross photosynthesis were wider, implying greater thermal eurytopy, with a higher Topt in Moorea versus Guam and Okinawa. Topt was above the maximum temperature in Moorea, but was similar to daily temperatures over 13% of the year in Okinawa, and 53% of the year in Guam. There was greater annual variation in daily temperatures in Okinawa than Guam or Moorea, which translated to large variation in the supply of metabolic energy and photosynthetically fixed carbon at higher latitudes. Despite these trends, the differences in TPCs for Pocillopora were not profoundly different across latitudes, reducing the likelihood that populations of these corals could better match their phenotypes to future more extreme temperatures through migration. Any such response would place a premium on high metabolic plasticity and tolerance of large seasonal variations in energy budgets.

Assessing the effects of cold storage regimes of North American Bombus Gynes

AbstractBumble bees are the primary commercial pollinators for greenhouse‐grown crops and managing them requires insight into the Bombus life cycle. However, some aspects of the life cycle are not fully understood. Once mated, adult Bombus gynes can be stored for a short term at a constant low temperature (CLT). However, survival rates for some species are low during CLT, particularly when storage periods exceed a month. To address this, we tested the hypothesis that Bombus gynes stored in a fluctuating thermal regime (FTR) have increased survival compared to gynes stored in CLT. Specifically, the FTR had a baseline temperature of 2°C, with a daily fluctuation to 20°C relative to the CLT of 2°C with no warming pulse. We tested the effects of FTR on gyne survival and post‐cold storage lipid content in three species used for commercial pollination in North America: B. vosnesenskii, B. huntii and B. impatiens. We further assessed how additional factors influence cold storage survival, including gyne body weight, body size and colony age. Survival responses varied among species. Bombus vosnesenskii and B. huntii had a lower survival rate in FTR compared to CLT, but B. impatiens gynes had a significantly higher survival rate in FTR. We did not observe significant effects of FTR on lipid stores for any species, but survival increased with an increasing initial weight prior to cold storage. Moreover, gynes produced later in the colony life cycle had lower body weight and decreased survival compared to early emerging gynes. Our study provides insight into how cold storage conditions interact with colony and gyne characteristics to influence captive overwintering survival. Our findings have economic applications for improving commercial rearing and efforts for conservation rearing of at‐risk Bombus species.

Formation of an anomalous thermal regime in autumn and spring on the European territory of Russia

Formation of an anomalous thermal regime in autumn and spring on the European territory of Russia

Formation of an anomalous thermal regime in autumn and spring on the European territory of Russia

Formation of an anomalous thermal regime in autumn and spring on the European territory of Russia

Effect of evaporator curvature on the local non-equilibrium heat regulation in two-phase closed thermosyphon embankment in permafrost regions

The evaporator curvatures can affect the heat transfer performance of two-phase closed thermosyphons (TPCTs) in permafrost regions. To explore the working features and control performance of TPCTs with different evaporator curvatures, two types of TPCTs with horizontal and inclined evaporator were designed. Then, a series of scale embankment models were conducted to test the thermal and deformation performance of the two TPCTs, including a TPCT embankment with inclined evaporator, a TPCT embankment with horizontal evaporator, and a contrast embankment without any TPCTs. The results show that the thermal regulation performance of the TPCT with horizontal evaporator is much better than that with inclined evaporator. The thermal regime difference caused by the vapour-liquid interface interaction occurs in the whole pipe domain above the liquid pool for the TPCT with inclined evaporator while it mainly exists in the condenser domain for the TPCT with horizontal evaporator. Meanwhile, the TPCT with horizontal evaporator can decrease the temperature gradient, and thus weaken the frost heave of the embankment. The TPCT with horizontal evaporator is more appropriate to adjust the local non-equilibrium heat process in embankment. The findings of this study supply a scientific reference for the design of TPCTs embankment in permafrost regions.

Controlled photothermal ablative processing of commercial polymers minimizing undesired thermal effects under high frequency femtosecond laser irradiation

The response of three commercial polymers (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) with different thermal properties under high repetition rates (1 kHz-1 MHz) with femtosecond (450 fs) multi-pulse laser irradiation at λ = 515 nm (1.4 J/cm2) is reported resulting in a complete study with controlling the ablation depth and minimizing collateral thermal effects. Tunable ablation depth is achieved accurately by varying the repetition rate at a constant fluence. The results are compared to a photothermal model that aims at explaining the heat accumulation effect of successive pulses as a function of the repetition rate and predicts three different heat regimes (non-cumulative, cumulative and saturation). The threshold frequencies for each regime can be estimated from the model, providing control for selecting frequency values and thermal regimes. Thermal analyses are performed to characterize the materials, concluding that thermal parameters are vital for selecting optimal materials and laser processing parameters.

Preparation and High-Temperature Resistance Properties of Phenolic Resin/Phosphate Hybrid Coatings.

In this study, a novel fabrication method was used to synthesize phenolic resin/phosphate hybrid coatings using aluminum dihydrogen phosphate (Al(H2PO4)3, hereafter denoted as Al), SC101 silica sol (Si) as the primary film-forming agent, and phenolic resin (PF) as the organic matrix. This approach culminated in the formation of Al+Si+PF organo-inorganic hybrid coatings. Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) results confirmed the successful integration of hybrid structures within these coatings. The crystalline structure of the coatings post-cured at various temperatures was elucidated using X-ray diffraction (XRD). Additionally, the surface and cross-sectional morphologies were meticulously analyzed using scanning electron microscopy (SEM), offering insights into the microstructural properties of the coatings. The coatings' porosities under diverse thermal and temporal regimes were quantitatively evaluated using advanced image processing techniques, revealing a significant reduction in porosity to a minimum of 5.88% following a thermal oxidation process at 600 °C for 10 h. The antioxidant efficacy of the phosphate coatings was rigorously assessed through cyclic oxidation tests, which revealed their outstanding performance. Specifically, at 300 °C across 300 h of cyclic oxidation, the weight losses recorded for phosphate varnish and the phenolic resin-infused phosphate coatings were 0.15 mg·cm-2 and 0.09 mg·cm-2, respectively. Furthermore, at 600 °C and over an identical period, the weight reduction was noted as 0.21 mg·cm-2 for phosphate varnish and 0.085 mg·cm-2 for the hybrid coatings, thereby substantiating the superior antioxidation capabilities of the phenolic resin hybrid coatings in comparison to the pure phosphate varnish.

Variation in resting respiration rate of Brook Trout among source populations: Implications for bioenergetic models

AbstractObjectiveOur objective was to compare wild and hatchery sourced Brook Trout Salvelinus fontinalis to determine the importance of source population on routine respiration rate (RRR), the major cost term in bioenergetic models.MethodsWe evaluated intraspecific variation in RRRs of one hatchery and four wild Brook Trout populations. Hatchery fish were obtained from the Bowden State Fish Hatchery in Elkins, West Virginia, and were the basis for the previously published bioenergetics model for the species. Wild fish were obtained from four headwater streams in West Virginia. Using intermittent respirometry, we measured and analyzed RRRs sequentially at 20, 16, and 12°C. Measures on hatchery fish were censored to restrict the dataset to similar sizes and temperatures as used with the wild populations. We used a suite of mixed effects models and one linear model to compare RRRs of hatchery fish with wild fish, as well as to determine whether wild populations differed.ResultWe found that the RRR of hatchery fish was double that of wild fish over the range of 12–20°C. Within the wild populations, the RRR of the Potomac drainage fish was lower than two of the three Ohio drainage populations despite all steams falling within 55 km of each other.ConclusionOur findings suggest that selective pressures at the hatchery, as well as factors that influence thermal regimes in wild populations, likely influence RRR in Brook Trout. More research is needed to identify correlates related to intraspecific variation in fish respiration rates. Most fish bioenergetics models are not based on, or calibrated to, the specific population to which they are applied. Therefore, we encourage greater efforts be expended to calibrate and validate such models in the future.

L-PBF AM process failures causal chain: an FMEA-based monitoring approach for process control

ABSTRACT The laser powder bed fusion (L-PBF) additive manufacturing process offers many advantages. However, its industrial integration still needs to be improved due to the certification constraints of the produced parts. Thus, this paper proposes a phenomenological causal chain of process failures to ensure the control of the L-PBF process and further certify the quality of the parts produced. Consequences of unsuitable thermal regimes are analysed using a failure mode and effects analysis (FMEA) approach, allowing a more global understanding of all the causal chain-related data. The proposed approach is based on standard acquisition equipment available on industrial machines and proves relevant for identifying process failures. Experimental validation of the proposed monitoring method is implemented on a use case using dedicated software. Finally, it is shown that the method is relevant in this confrontation and compatible with the time scale of the process for future NC integration and real-time monitoring.

Лизиметрическим исследованиям в Федеральном научном центре кормопроизводства и агроэкологии имени В.Р. Вильямса исполнилось 50 лет

The study of ecosystems, biological and ecological features of perennial grasses, soils, groundwater and monitoring of their dynamics are impossible without lysimetric studies. Lysimeters serve as a reliable means of studying and managing agroecosystems and the entire complex of plant development factors. At the All-Union Williams feed research Institute, lysimetric studies on the study, regulation and forecasting of water, food and thermal regimes of reclaimed natural forage lands in the agroecosystem "soil — plant — infiltration runoff" on irrigated pastures in the conditions of the Central District of the Non-Chernozem zone (Moscow region) were started at the Lysimetric Station built in 1972. The station includes a laboratory building, a tunnel room with a depth of about 3 m and a length of more than 40 m, a hardware room, lysimetric devices and installations of a special design. The lysimetric installation allows you to jointly study the water balance, the balance of chemicals and automate the observation processes. The developed design of the measuring equipment increased the accuracy of the experiment, and due to its small dimensions, it allowed experiments to significantly expand the range of studied groundwater depths (from 0.75 m to 2 m). Lysimeters of 2 types (for water balance and agrochemical studies) are designed for year-round observations. The results of lysimetric studies are extrapolated to areas with similar environmental conditions.

Stability of monovarietal Sicilian olive oils under different storage condition: Chemical composition, sensory characteristics, and consumer preference

Monovarietal olive oils, known for their distinct aromatic profiles, face challenges in preserving their initial quality due to variations in stability and susceptibility to oxidative deterioration. This study focused on the storage stability of two Italian cultivars, ‘Biancolilla’ and ‘Cerasuola’, from Sicily, chosen for their aromatic complexity and divergent storage stability. Oils, whether filtered or unfiltered, underwent storage at two thermal regimes (18 °C and – 20 °C) over a year. The combination of filtration and low-temperature storage was employed to mitigate oxidative deterioration and hydrolytic processes, as filtration removes suspended particles and emulsified water, while low temperatures slow down enzymatic activities and oxidative reactions, thereby enhancing the overall stability and shelf life of the olive oils. Unfiltered samples at room temperature showed a significant increase in secoiridoid aglycone derivatives (Hydroxytyrosol and Tyrosol) due to hydrolytic processes, along with a decrease in secoiridoid aglycone. Filtration delayed these processes, with a more pronounced effect observed when combined with −20 °C storage. Sensory analysis identified the emergence of the “fusty” defect in the less resilient ‘Biancolilla’ cultivar after six months, a phenomenon mitigated by filtration and freezing. Consumer tests validated these findings. In summary, the synergistic approach of combining filtration with low-temperature storage emerges as a promising strategy for maintaining high-quality standards, especially for less stable monovarietal extra virgin olive oils. This strategy ensures compliance with EU regulations beyond the conventional 12-month shelf life, offering a practical solution for preserving the nutritional and sensory quality of olive oil.

Warming alters life-history traits and competition in a phage community.

Host-parasite interactions are highly susceptible to changes in temperature due to mismatches in species thermal responses. In nature, parasites often exist in communities, and responses to temperature are expected to vary between host-parasite pairs. Temperature change thus has consequences for both host-parasite dynamics and parasite-parasite interactions. Here, we investigate the impact of warming (37°C, 40°C, and 42°C) on parasite life-history traits and competition using the opportunistic bacterial pathogen Pseudomonas aeruginosa (host) and a panel of three genetically diverse lytic bacteriophages (parasites). We show that phages vary in their responses to temperature. While 37°C and 40°C did not have a major effect on phage infectivity, infection by two phages was restricted at 42°C. This outcome was attributed to disruption of different phage life-history traits including host attachment and replication inside hosts. Furthermore, we show that temperature mediates competition between phages by altering their competitiveness. These results highlight phage trait variation across thermal regimes with the potential to drive community dynamics. Our results have important implications for eukaryotic viromes and the design of phage cocktail therapies.IMPORTANCEMammalian hosts often elevate their body temperatures through fevers to restrict the growth of bacterial infections. However, the extent to which fever temperatures affect the communities of phages with the ability to parasitize those bacteria remains unclear. In this study, we investigate the impact of warming across a fever temperature range (37°C, 40°C, and 42°C) on phage life-history traits and competition using a bacterium (host) and bacteriophage (parasite) system. We show that phages vary in their responses to temperature due to disruption of different phage life-history traits. Furthermore, we show that temperature can alter phage competitiveness and shape phage-phage competition outcomes. These results suggest that fever temperatures have the potential to restrict phage infectivity and drive phage community dynamics. We discuss implications for the role of temperature in shaping host-parasite interactions more widely.