Predicting the potential effects of changes in climate on freshwater species requires an understanding of the relationships between physiological traits and environmental conditions among populations. While water temperature is a primary factor regulating metabolic rates in freshwater ectotherms, how metabolic rates vary across the species range is unclear. In addition, photoperiod has also been hypothesised to influence metabolic rates in freshwater taxa based on seasonal changes in activity rates. Using an experimental approach, we investigated whether variation in routine metabolic rate (RMR) and sensitivity of RMR to changes in temperature are correlated with local thermal regimes, photoperiods and body mass among ten populations across the geographic range of the Bluntnose minnow (
Geometric morphometrics provides a powerful means of evaluating differences in phenotypic traits among specimens. However, inferences of trait variability can be confounded when measurements are based on preserved samples. We evaluated effects of ethanol preservation on morphology over a 22‐week time period for a Laurentian Great Lakes invasive fish, round goby (
- Award ID(s):
- 1811821
- NSF-PAR ID:
- 10360284
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Morphology
- Volume:
- 282
- Issue:
- 12
- ISSN:
- 0362-2525
- Page Range / eLocation ID:
- p. 1772-1784
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract Pimephales notatus ), a North American freshwater fish species. Routine metabolic rate data were collected from populations acclimatised to three temperature treatments (9, 18 and 27°C) and correlated with water temperature and photoperiod estimates at collection locations for each population. Routine metabolic rate was negatively correlated with minimum photoperiod at 9°C, negatively correlated with weekly high temperature at 18°C and positively correlated with weekly high temperature at 27°C. Body mass was also a predictor of RMR at each temperature treatment. Thermal sensitivity of RMR was positively correlated with weekly high temperature, indicating that individuals from warmer low latitude populations experienced greater sensitivity of RMR to changes in temperature than individuals from cooler high latitude populations. These results indicate differential responses among populations to variation in temperature and suggest the importance of recognising this variation when characterising responses of freshwater taxa to increases in water temperature. -
more » « less
Abstract Lakes are vulnerable to climate change, and warming rates in the Arctic are faster than anywhere on Earth. Fishes are sensitive to changing temperatures, which directly control physiological processes. Food availability should partly dictate responses to climate change because energetic demands change with temperature, but few studies have simultaneously examined temperature and food availability.
We used a fully factorial experiment to test effects of food availability and temperature (7.6, 12.7, and 17.4°C; 50 days) on growth, consumption, respiration, and excretion, and effects of temperature (12 and 19.3°C; 27 days) on habitat use and growth of a common, but understudied, mid‐level consumer, slimy sculpin
Cottus cognatus , in arctic lakes. We also used bioenergetics modelling to predict consumptive demand under future warming scenarios.Growth rates were 3.4× higher at 12.7°C in high food compared to low food treatments, but the magnitude of differences depended on temperature. Within low food treatments, there was no statistical difference in growth rates among temperatures, suggesting food limitation. Consumption, respiration, and nitrogen excretion increased with temperature independent of food availability. Lower growth rates coincided with lower phosphorus excretion at the highest temperature, suggesting that fish selectively retained phosphorus at high temperatures and low food. In habitat choice experiments, fish were more likely to use the 12°C side of the tank, closely matching their optimal temperature. We predicted a 9% increase in consumption is required to maintain observed growth under a 4°C warming scenario.
These results highlight considering changes in food resources and other associated indirect effects (e.g. excretion) that accompany changing temperatures with climate change. Depending on how food webs respond to warming, fish may cope with predicted warming if density‐dependent feedback maintains population sizes.
-
more » « less
Abstract The study was conducted to quantify laryngeal cartilage matrix composition and to investigate its relationship with cartilage shape in a mouse model. A sample of 30 mice (CD‐1 mouse,
Mus musculus ) from five age groups (postnatal Days 2, 21, 90, 365, and 720) were used. Three‐dimensional mouse laryngeal thyroid cartilage reconstructions were generated from contrast‐enhanced micro‐computed tomography (CT) image stacks. Cartilage matrix composition was estimated as Hounsfield units (HU). HU were determined by overlaying 3D reconstructions as masks on micro‐CT image stacks and then measuring the attenuation. Cartilage shape was quantified with landmarks placed on the surface of the thyroid cartilage. Shape differences between the five age groups were analyzed using geometric morphometrics and multiparametric analysis of landmarks. The relationship between HU and shape was investigated with correlational analyses. Among five age groups, HU became higher in older animals. The shape of the thyroid cartilage changes with age throughout the entire life of a mouse. The changes in shape were not synchronized with changes in cartilage matrix composition. The thyroid cartilage of young and oldM. musculus larynx showed a homogenous mineralization pattern. High‐resolution contrast‐enhanced micro‐CT imaging makes the mouse larynx accessible for analysis of genetic and environmental factors affecting shape and matrix composition. -
more » « less
Abstract Multiple highly divergent lineages have been identified within
Ligia occidentalis sensu lato , a rocky supralittoral isopod distributed along a ~3000 km latitudinal gradient that encompasses several proposed marine biogeographic provinces and ecoregions in the eastern Pacific. Highly divergent lineages have nonoverlapping geographic distributions, with distributional limits that generally correspond with sharp environmental changes. Crossbreeding experiments suggest postmating reproductive barriers exist among some of them, and surveys of mitochondrial and nuclear gene markers do not show evidence of hybridization. Populations are highly isolated, some of which appear to be very small; thus, the effects of drift are expected to reduce the efficiency of selection. Large genetic divergences among lineages, marked environmental differences in their ranges, reproductive isolation, and/or high isolation of populations may have resulted in morphological differences inL. occidentalis , not detected yet by traditional taxonomy. We used landmark‐based geometric morphometric analyses to test for differences in body shape among highly divergent lineages ofL. occidentalis , and among populations within these lineages. We analyzed a total of 492 individuals from 53 coastal localities from the southern California Bight to Central Mexico, including the Gulf of California. We conducted discriminant function analyses (DFA s) on body shape morphometrics to assess morphological variation among genetically differentiated lineages and their populations. We also tested for associations between phylogeny and morphological variation, and whether genetic divergence is correlated to multivariate morphological divergence. We detected significant differences in body shape among highly divergent lineages, and among populations within these lineages. Nonetheless, neither lineages nor populations can be discriminated on the basis of body shape, because correct classification rates of cross‐validatedDFA s were low. Genetic distance and phylogeny had weak to no effect on body shape variation. The supralittoral environment appears to exert strong stabilizing selection and/or strong functional constraints on body shape inL. occidentalis , thereby leading to morphological stasis in this isopod. -
more » « less
Abstract Primate craniofacial growth is traditionally assumed to cease upon maturation or at least be negligible, whereas bony remodeling is typically associated with advanced adult age and, in particular, tooth loss. Therefore, size and shape of the craniofacial skeleton of young and middle‐aged adults should be stable. However, research on both modern and historic human samples suggests that portions of the
CFS exhibit age‐related changes in mature individuals, both related to and independent of tooth loss. These results demonstrate that the age‐category ‘adult’ is heterogeneous, containing individuals demonstrating post‐maturational age‐related variation, but the topic remains understudied outside of humans and in the cranial vault and base. Our research quantifies variation in a sample of captive adult female baboons (n =CFS . Craniometric landmarks and sliding semilandmarks were collected fromcomputed tomography (CT) scans of adult baboons aged 7–32 years old. To determine whether craniofacial morphology is sensitive to aging mechanisms and whether any such effects are differentially distributed throughout the cranium, geometric morphometric techniques were employed to compare the shapes of various cranial regions among individuals of increasing age. Unexpectedly, the biggest form differences were observed between young and middle‐aged adults, rather than between adults with full dentitions and those with some degree of tooth loss. Shape variation was greatest in masticatory and nuchal musculature attachment areas. Our results indicate that thecraniofacial skeleton changes form during adulthood in baboons, raising interesting questions about the molecular and biological mechanisms governing these changes.
