Settlement of gilthead sea bream Sparus aurata L. in a southern Irish Sea coastal habitat

For the first time, early juvenile stages of gilthead sea bream Sparus aurata were consistently collected in a brackish estuarine area in the southern Irish Sea over a period of 4 months. This finding, in connection with other recent evidence, raises the possibility that S. aurata may currently spawn, or at least successfully settle, in more northern locations than previously known.     

An ES-like cell line from the marine fish Sparus aurata: Characterization and chimaera production

Embryonic stem (ES) cells provide a unique tool for cell-mediated gene transfer and targeted gene mutations due to the possibility of in vitro selection of desired genotypes. When selected cells contribute to the germ line in chimaeric embryos, transgenic animals may be generated with modified genetic traits. Though the ES cell approach has up to now been limited to mice, there is an increasing interest to develop this technology in both model and commercial fish species, with so far promising results in the medaka and zebrafish. In this study, we present evidence regarding a long-term stable cell line (SaBE-1c), derived from embryonic cells of the aquaculture marine fish Sparus aurata which has been characterized for (i) cell proliferation, (ii) chromosome complement, (iii) molecular markers, and (iv) in vitro tests of pluripotency by alkaline phosphatase (AP) staining, telomerase activity, and induced cell differentiation. These cells have proved their pluripotent capacities by in vitro tests. Furthermore, we have demonstrated their ability to produce chimaeras and to contribute to the formation of tissues from all three embryonic germ layers. These features suggest that SaBE-1c cells have the potential for multiple applications for the ES technology in fish, with the added value of originating from an economically important species.     

Ontogenesis of opercular deformities in gilthead sea bream Sparus aurata: a histological description

The aim of this study was to characterize histological changes during opercular osteogenesis in farmed gilthead sea bream Sparus aurata larvae from 7 to 69 days post hatching (dph) and compare normal osteogenesis with that of deformed opercles. Mild opercular deformities were first detected in 19 dph larvae by folding of the opercle's distal edge into the gill chamber. Here, the variation in the phenotype and the irregular bone structure at the curled part of the opercles is described and compared with the histology of normal opercles. Results indicated that deformed opercles still undergo bone growth with the addition of new matrix by osteoblasts at the opercular surface, especially at its edges. No significant difference was found in bone thickness between deformed and normal opercles. In addition to differences in bone architecture, differences in collagen fibre thickness between normal and deformed opercles were also found.     

Light and feeding entrainment of the molecular circadian clock in a marine teleost (Sparus aurata)

Daily light and feeding cycles act as powerful synchronizers of circadian rhythmicity. Ultimately, these external cues entrain the expression of clock genes, which generate daily rhythmic behavioral and physiological responses in vertebrates. In the present study, we investigated clock genes in a marine teleost (gilthead sea bream). Partial cDNA sequences of key elements from both positive (Bmal1, Clock) and negative (Per2, Cry1) regulatory loops were cloned before studying how feeding time affects the daily rhythms of locomotor activity and clock gene expression in the central (brain) and peripheral (liver) oscillators. To this end, all fish were kept under a light-dark (LD) cycle and were divided into three experimental groups, depending on the time of their daily meal: mid-light (ML), mid-darkness (MD), or at random (RD) times. Finally, the existence of circadian control on gene expression was investigated in the absence of external cues (DD?+?RD). The behavioral results showed that seabream fed at ML or RD displayed a diurnal activity pattern (>91% of activity during the day), whereas fish fed at MD were nocturnal (89% of activity during the night). Moreover, seabream subjected to regular feeding cycles (ML and MD groups) showed food-anticipatory activity (FAA). Regardless of the mealtime, the daily rhythm of clock gene expression in the brain peaked close to the light-dark transition in the case of Bmal1 and Clock, and at the beginning of the light phase in the case of Per2 and Cry1, showing the existence of phase delay between the positive and negative elements of the molecular clock. In the liver, however, the acrophases of the daily rhythms differed depending on the feeding regime: the maximum expression of Bmal1 and Clock in the ML and RD groups was in antiphase to the expression pattern observed in the fish fed at MD. Under constant conditions (DD?+?RD), Per2 and Cry1 showed circadian rhythmicity in the brain, whereas Bmal1, Clock, and Per2 did in the liver. Our results indicate that the seabream clock gene expression is endogenously controlled and in liver it is strongly entrained by food signals, rather than by the LD cycle, and that scheduled feeding can shift the phase of the daily rhythm of clock gene expression in a peripheral organ (liver) without changing the phase of these rhythms in a central oscillator (brain), suggesting uncoupling of the light-entrainable oscillator (LEO) from the food-entrainable oscillator (FEO). These findings provide the basis and new tools for improving our knowledge of the circadian system and entraining pathways of this fish species, which is of great interest for the Mediterranean aquaculture. (Author correspondence: javisan@um.es).     

Oxygen uptake,heart rate and activities of locomotor muscles during a critical swimming speed protocol in the gilthead sea bream Sparus aurata

Oxygen uptake, heart rate and contraction frequencies of slow oxidative (SO) and fast glycolytic (FG) muscle were measured simultaneously in gilthead seabream Sparus aurata submitted to stepwise increases in current speed in a swimming respirometer. Variation in oxygen uptake was closely related to variation in heart rate, over initial steps these rose in concert with an increase in contraction frequency of SO muscle. There was an asymptote in oxygen uptake and heart rate at high speeds that reflected a transition from exclusive use of aerobic SO muscle to a combination of SO and anaerobic FG muscle, and which preceded fatigue.     

气候变暖对昆虫影响研究进展

"全球气候变化"已成为国内外最受关注的环境问题。气候变化中以温度升高为特征的气候变暖对变温动物昆虫自身及其所在的生物群落产生直接或间接影响。从研究内容与研究方法2个方面综述了气候变暖对昆虫影响研究的国内外进展。气候变暖导致昆虫发生期提前,地理分布向更高纬度和海拔地区扩散,低温适生种种群密度下降,高温适生种种群密度增加。气候变暖改变寄主植物—害虫—天敌的物候同步性和昆虫原有种间互作关系,影响植食性昆虫的寄主植物范围和取食为害程度。长期的气候变暖带来的强烈的选择性压力引起某些昆虫种群的基因组发生变异。以日均温升高、日最高气温升高和昼夜温差变化等为主要特征气候变暖对昆虫发育、繁殖及存活等生态学指标产生重要影响。研究方法上主要是利用野外直接观察法、回归预测模型、有效积温模型、CLIMEX和GIS等生态风险评估软件、生物化石比较技术、人工气候下生态试验、检测标记基因频率变化等方法来研究气候变暖对昆虫的影响。最后简要评述了已有研究的不足并指出未来的研究方向:(1)气候变暖情景下开展昆虫种间互作研究并拓展研究对象;(2)高温下昆虫适应性研究;(3)建立完善人工模拟气候下的实验方法;(4)构建昆虫有效生态机理模型。     

Effect of decreased environmental salinity on growth hormone cells in the gilthead sea bream (Sparus aurata)

The effect of decreased environmental salinity on growth hormone producing cells (GH cells) of the adenohypophysial proximal pars distalis has been studied in the gilthead sea bream ( Sparus aurata L.) adapted to sea water (SW, 980 mosmol kg ⁻¹) and brackish water (BW, 200 mosmol kg ⁻¹). A combined immunocytochemical, morphometric and electron microscopic study was carried out. GH cells offish adapted to BW occupied a greater hypophysial volume (about 21% of the total hypophysial volume in BW, 17% in SW) and had a larger nuclear area (mean 16 μm² in BW, 13 μm² in SW) than GH cells of SW-adapted fish. The immunoreactivity against a salmon GH-antiserum was lower in BW (mean optical density 142 in BW, 159 in SW). Ultrastructural characteristics of GH cells of BW-adapted fish were distended rough endo-plasmatic reticulum and large secretory granules (about 216 nm in diameter for BW, 209 nm in SW). Volumetric, densitometric and ultrastructural evidence suggested that the synthesis and release of GH were activated in S. aurata adapted to hypo-osmotic environment.     

Effects of global climate change on marine and estuarine fishes and fisheries

Global climate change is impacting and will continue to impact marine and estuarine fish and fisheries. Data trends show global climate change effects ranging from increased oxygen consumption rates in fishes, to changes in foraging and migrational patterns in polar seas, to fish community changes in bleached tropical coral reefs. Projections of future conditions portend further impacts on the distribution and abundance of fishes associated with relatively small temperature changes. Changing fish distributions and abundances will undoubtedly affect communities of humans who harvest these stocks. Coastal-based harvesters (subsistence, commercial, recreational) may be impacted (negatively or positively) by changes in fish stocks due to climate change. Furthermore, marine protected area boundaries, low-lying island countries dependent on coastal economies, and disease incidence (in aquatic organisms and humans) are also affected by a relatively small increase in temperature and sea level. Our interpretations of evidence include many uncertainties about the future of affected fish species and their harvesters. Therefore, there is a need to research the physiology and ecology of marine and estuarine fishes, particularly in the tropics where comparatively little research has been conducted. As a broader and deeper information base accumulates, researchers will be able to make more accurate predictions and forge relevant solutions.     

Effect of music stimulus on gilthead seabream Sparus aurata physiology under different light intensity in a re‐circulating water system

The aim of the present study was to evaluate music effects (Mozart, K525) on gilthead seabream Sparus aurata and investigate whether its response to music was differentiated when combined with different lighting conditions. Therefore, S. aurata (mean ±s .e . 1·51 ± 0·01 g) were reared in re‐circulating water system under 80 and 200 lx and subjected to 2 and 4 h of music transmissions or to no music at all (control, ambient noise only). Underwater ambient noise of the equipment (e.g. pumps and aerators) in all experimental tanks was 121 dB re 1 μPa and music transmitted was set at 140 dB re 1 μPa. During the first 89 days of rearing, music resulted in enhanced growth. Nevertheless, at the end of the experiment (on day 117) no significant differences were found for body mass but music treatment resulted in more homogeneous fish populations than controls. Brain neurotransmitter levels were reduced especially when music transmission was combined with 200 lx. Feed utilization was significantly improved when fish were subjected to 4 h of music and 200 lx, while stomach proteolytic enzymes and intestine total carbohydrases were lower and higher, respectively, compared to controls. Some differences were also observed in liver and plasma fatty acids composition. The present results provide the initial evidence that music transmission under specific rearing conditions could have enhancing effects on S. aurata growth performance, at least at specific fish sizes. Moreover, the observed music effects on several aspects of fish physiology (e.g. digestive enzymes, fatty acid composition and brain neurotransmitters) imply that music could possibly provide even further enhancement in growth, quality, welfare and production.     

Earlier plant flowering in spring as a response to global warming in the Washington, DC, area

Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from -3.2 to -46 days, while those for later-flowering species range from +3.1 to +10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (T _min).     

Adaptive microevolutionary responses to simulated global warming in Simocephalus vetulus: a mesocosm study

Although several studies suggest the occurrence of microevolutionary responses that may allow local persistence of populations under global warming, rigorous experimental proof is lacking. Here, we combined the realism and rigid, replicated experimental design of a large‐scale mesocosm study where populations of the zooplankter Simocephalus vetulus were exposed for 1 year to different global warming scenarios with a life table experiment under laboratory conditions at three temperatures that eliminated confounding, nongenetic factors. Our results provide solid proof for a rapid microevolutionary response to global warming in both survival and the subcomponents of individual performance (age at reproduction and number of offspring), which may allow populations of S. vetulus to persist locally under predicted scenarios of global warming. Such microevolutionary responses may buffer changes in community structure under global warming and help explain the outcome of previous mesocosm studies finding only marginal effects of global warming at the community level.     

Amazon Basin climate under global warming: the role of the sea surface temperature

The Hadley Centre coupled climate-carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both the tropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely, a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry season soil moisture deficits from being recharged through the SAM season, leading to a perennial soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary productivity (NPP). A further 23% NPP reduction occurs in response to a 3.5 degrees C warmer air temperature associated with a global mean SST warming.     

Ocean cleaning stations under a changing climate: biological responses of tropical and temperate fish‐cleaner shrimp to global warming

Cleaning symbioses play an important role in the health of certain coastal marine communities. These interspecific associations often occur at specific sites (cleaning stations) where a cleaner organism (commonly a fish or shrimp) removes ectoparasites/damaged tissue from a ‘client’ (a larger cooperating fish). At present, the potential impact of climate change on the fitness of cleaner organisms remains unknown. This study investigated the physiological and biochemical responses of tropical (Lysmata amboinensis) and temperate (L. seticaudata) cleaner shrimp to global warming. Specifically, thermal limits (CTMax), metabolic rates, thermal sensitivity, heat shock response (HSR), lipid peroxidation [malondialdehyde (MDA) concentration], lactate levels, antioxidant (GST, SOD and catalase) and digestive enzyme activities (trypsin and alkaline phosphatase) at current and warming (+3 °C) temperature conditions. In contrast to the temperate species, CTMax values decreased significantly from current (24–27 °C) to warming temperature conditions (30 °C) for the tropical shrimp, where metabolic thermal sensitivity was affected and the HSR was significantly reduced. MDA levels in tropical shrimp increased dramatically, indicating extreme cellular lipid peroxidation, which was not observed in the temperate shrimp. Lactate levels, GST and SOD activities were significantly enhanced within the muscle tissue of the tropical species. Digestive enzyme activities in the hepatopancreas of both species were significantly decreased by warmer temperatures. Our data suggest that the tropical cleaner shrimp will be more vulnerable to global warming than the temperate Lysmata seticaudata; the latter evolved in a relatively unstable environment with seasonal thermal variations that may have conferred greater adaptive plasticity. Thus, tropical cleaning symbioses may be challenged at a greater degree by warming‐related anthropogenic forcing, with potential cascading effects on the health and structuring of tropical coastal communities (e.g. coral reefs).     

Free Air Temperature Increase (FATI): a new tool to study global warming effects on plants in the field

A new technique, called Free Air Temperature Increase (FATI), was developed to artificially induce increased canopy temperature in field conditions without the use of enclosures. This acronym was chosen in analogy with FACE (Free Air CO₂ Enrichment), a technique which produces elevated CO₂ concentrations [CO₂] in open field conditions. The FATI system simulates global warming in small ecosystems of limited height, using infrared heaters from which all radiation below 800 nm is removed by selective cut-off filters to avoid undesirable photomorpho-genetic effects. An electronic control circuit tracks the ambient canopy temperature in an unheated reference plot with thermocouples, and modulates the radiant energy from the lamps to produce a 2.5°C increment in the canopy temperature of an associated heated plot (continuously day and night). This pre-set target differential is relatively-constant over time due to the fast response of the lamps and the use of a proportional action controller (the standard deviation of this increment was <1°C in a 3 week field study with 1007 measurements). Furthermore, the increase in leaf temperature does not depend on the vertical position within the canopy or on the height of the stand. Possible applications and alternative designs are discussed.     

Behavioral buffering of global warming in a cold‐adapted lizard

Alpine lizards living in restricted areas might be particularly sensitive to climate change. We studied thermal biology of Iberolacerta cyreni in high mountains of central Spain. Our results suggest that I. cyreni is a cold‐adapted thermal specialist and an effective thermoregulator. Among ectotherms, thermal specialists are more threatened by global warming than generalists. Alpine lizards have no chance to disperse to new suitable habitats. In addition, physiological plasticity is unlikely to keep pace with the expected rates of environmental warming. Thus, lizards might rely on their behavior in order to deal with ongoing climate warming. Plasticity of thermoregulatory behavior has been proposed to buffer the rise of environmental temperatures. Therefore, we studied the change in body and environmental temperatures, as well as their relationships, for I. cyreni between the 1980s and 2012. Air temperatures have increased more than 3.5°C and substrate temperatures have increased by 6°C in the habitat of I. cyreni over the last 25 years. However, body temperatures of lizards have increased less than 2°C in the same period, and the linear relationship between body and environmental temperatures remains similar. These results show that alpine lizards are buffering the potential impact of the increase in their environmental temperatures, most probably by means of their behavior. Body temperatures of I. cyreni are still cold enough to avoid any drop in fitness. Nonetheless, if warming continues, behavioral buffering might eventually become useless, as it would imply spending too much time in shelter, losing feeding, and mating opportunities. Eventually, if body temperature exceeds the thermal optimum in the near future, fitness would decrease abruptly.     

The toughest animals of the Earth versus global warming: Effects of long‐term experimental warming on tardigrade community structure of a temperate deciduous forest

Understanding how different taxa respond to global warming is essential for predicting future changes and elaborating strategies to buffer them. Tardigrades are well known for their ability to survive environmental stressors, such as drying and freezing, by undergoing cryptobiosis and rapidly recovering their metabolic function after stressors cease. Determining the extent to which animals that undergo cryptobiosis are affected by environmental warming will help to understand the real magnitude climate change will have on these organisms. Here, we report on the responses of tardigrades within a five‐year‐long, field‐based artificial warming experiment, which consisted of 12 open‐top chambers heated to simulate the projected effects of global warming (ranging from 0 to 5.5°C above ambient temperature) in a temperate deciduous forest of North Carolina (USA). To elucidate the effects of warming on the tardigrade community inhabiting the soil litter, three community diversity indices (abundance, species richness, and Shannon diversity) and the abundance of the three most abundant species (Diphascon pingue, Adropion scoticum, and Mesobiotus sp.) were determined. Their relationships with air temperature, soil moisture, and the interaction between air temperature and soil moisture were tested using Bayesian generalized linear mixed models. Despite observed negative effects of warming on other ground invertebrates in previous studies at this site, long‐term warming did not affect the abundance, richness, or diversity of tardigrades in this experiment. These results are in line with previous experimental studies, indicating that tardigrades may not be directly affected by ongoing global warming, possibly due to their thermotolerance and cryptobiotic abilities to avoid negative effects of stressful temperatures, and the buffering effect on temperature of the soil litter substrate.     

Radiation and speciation of pelagic organisms during periods of global warming: the case of the common minke whale, Balaenoptera acutorostrata

How do populations of highly mobile species inhabiting open environments become reproductively isolated and evolve into new species? We test the hypothesis that elevated ocean‐surface temperatures can facilitate allopatry among pelagic populations and thus promote speciation. Oceanographic modelling has shown that increasing surface temperatures cause localization and reduction of upwelling, leading to fragmentation of feeding areas critical to pelagic species. We test our hypothesis by genetic analyses of populations of two closely related baleen whales, the Antarctic minke whale (Balaenoptera bonaerensis) and common minke whale (Balaenoptera acutorostrata) whose current distributions and migration patterns extent are largely determined by areas of consistent upwelling with high primary production. Phylogeographic and population genetic analyses of mitochondrial DNA control‐region nucleotide sequences collected from 467 whales sampled in four different ocean basins were employed to infer the evolutionary relationship among populations of B. acutorostrata by rooting an intraspecific phylogeny with a population of B. bonaerensis. Our findings suggest that the two species diverged in the Southern Hemisphere less than 5 million years ago (Ma). This estimate places the speciation event during a period of extended global warming in the Pliocene. We propose that elevated ocean temperatures in the period facilitated allopatric speciation by disrupting the continuous belt of upwelling maintained by the Antarctic Circumpolar Current. Our analyses revealed that the current populations of B. acutorostrata likely diverged after the Pliocene some 1.5 Ma when global temperatures had decreased and presumably coinciding with the re‐establishment of the polar–equatorial temperature gradient that ultimately drives upwelling. In most population samples, we detected genetic signatures of exponential population expansions, consistent with the notion of increasing carrying capacity after the Pliocene. Our hypothesis that prolonged periods of global warming facilitate speciation in pelagic marine species that depend on upwelling should be tested by comparative analyses in other pelagic species.     

基于文献计量分析土壤微生物对气候变暖的响应

【背景】面对全球气候变暖,土壤微生物在陆地生态系统对全球变暖反馈中起到了至关重要的作用。【目的】了解土壤微生物对气候变暖响应研究的发展现状、研究热点及前沿动态,厘清当前该研究领域的知识结构关系。【方法】以1999-2021年Web of Science核心数据库中土壤微生物对气候变暖响应研究已发表的3 189篇论文为数据源,利用Vosviewer和CiteSpace软件对年发文量、文献被引频次、作者、机构、国家、学科和关键词等进行可视化分析。【结果】研究总体呈逐步增长趋势,经历缓慢增长、稳步增长和高速增长3个阶段;高被引论文均发表在国际顶级期刊上,研究成果具有较高的学术影响力。在学科融合与合作交流方面,环境科学、生态学和土壤学是该研究领域的主要学科,而多学科交叉学在该领域占有重要地位;作者骆亦其、Schuur和周集中是该领域核心学者,作者之间的合作关系主要以同一研究团队内部合作为主;主要的科研机构有中国科学院、加利福尼亚大学和美国能源部,各科研机构之间合作较为紧密;中国、美国和欧洲是土壤微生物对气候变暖响应研究领域的主要力量,国家之间相互合作程度高。该领域的主要研究热点是气候变暖改变了土壤微生物的群落结构组成、多样性和生理生化功能,进而对地球化学物质循环产生影响;土壤微生物在土壤碳库释放中的作用机理和调控机制是该领域研究前沿。【结论】目前,不同生态系统研究中土壤微生物对增温的响应与适应机制存在着差异,而且对微生物碳功能基因和多环境交互因子的研究较少。因此,建议后期应更加聚焦特定生态系统的细化研究,开展大范围、大尺度、长时期的定位研究,加强对微生物碳降解和碳固定功能基因的研究,多关注环境因子变化的交互作用对土壤微生物生态过程的影响。     

Changes in chromosomal polymorphism and global warming: The case of Drosophila subobscura from Apatin (Serbia)

In this study, chromosomal inversion polymorphism data for a natural population of Drosophila subobscura from a swampy region near the town of Apatin (Serbia) were compared with data for the same population collected approximately 15 years earlier. The pattern of chromosomal inversion polymorphism changed over time. There were significant increases in the frequency of characteristic southern latitude ("warm" adapted) chromosomal arrangements and significant decreases in the frequency of characteristic northern latitude ("cold" adapted) chromosomal arrangements in the O and U chromosomes. The chromosomal arrangements O(3+4) and O(3+4) (+) (22) (derived from the O(3+4) arrangement) showed significant increases in 2008 and 2009 with regard to the 1994 sample. There was also a significant increase (～50%) in the U(1) (+) (2) arrangement, while U(1+8) (+) (2) (a typical southern arrangement) was detected for the first time. Since the Apatin swampy population of D. subobscura has existed for a long time in a stable habitat with high humidity that has not been changed by man our results indicate that natural selection has produced chromosomal changes in response to the increase in temperature that has occurred in the Balkan Peninsula of central southeastern European.     

Investigating the potential impacts of climate change on a marine turtle population

Recent increases in global temperatures have affected the phenology and survival of many species of plants and animals. We investigated a case study of the effects of potential climate change on a thermally sensitive species, the loggerhead sea turtle, at a breeding location at the northerly extent of the range of regular nesting in the United States. In addition to the physical limits imposed by temperature on this ectothermic species, sea turtle primary sex ratio is determined by the temperature experienced by eggs during the middle third of incubation. We recorded sand temperatures and used historical air temperatures (ATs) at Bald Head Island, NC, to examine past and predict future sex ratios under scenarios of warming. There were no significant temporal trends in primary sex ratio evident in recent years and estimated mean annual sex ratio was 58% female. Similarly, there were no temporal trends in phenology but earlier nesting and longer nesting seasons were correlated with warmer sea surface temperature. We modelled the effects of incremental increases in mean AT of up to 7.5°C, the maximum predicted increase under modelled scenarios, which would lead to 100% female hatchling production and lethally high incubation temperatures, causing reduction in hatchling production. Populations of turtles in more southern parts of the United States are currently highly female biased and are likely to become ultra‐biased with as little as 1°C of warming and experience extreme levels of mortality if warming exceeds 3°C. The lack of a demonstrable increase in AT in North Carolina in recent decades coupled with primary sex ratios that are not highly biased means that the male offspring from North Carolina could play an increasingly important role in the future viability of the loggerhead turtle in the Western Atlantic.