Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Journal of Thermal Biology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

44 records · Page 3Linked to original sources

Engineering a future for amphibians under climate change

1. Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. 2. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydroperiod or water levels at breeding sites. 3. Synthesis and applications. There are currently few meaningful management actions that will tangibly impact the pervasive threat of climate change on amphibians. A host of potentially useful but poorly tested actions could be incorporated into local or regional management plans, programmes and activities for amphibians. Examples include: installation of irrigation sprayers to manipulate water potentials at breeding sites; retention or supplementation of natural and artificial shelters (e.g. logs, cover boards) to reduce desiccation and thermal stress; manipulation of canopy cover over ponds to reduce water temperature; and, creation of hydrologoically diverse wetland habitats capable of supporting larval development under variable rainfall regimes. We encourage researchers and managers to design, test and scale up new initiatives to respond to this emerging crisis.

Journal of Applied Ecology↗

Assessment of potential recovery viability for Colorado Pikeminnow Ptychocheilus lucius in the Colorado River in Grand Canyon

Colorado Pikeminnow Ptychocheilus lucius, the Colorado River’s top native predatory fish, was historically distributed from the Gulf of California delta to the upper reaches of the Green, Colorado, and San Juan rivers in the Colorado River basin in the Southwestern US. In recent decades Colorado Pikeminnow population abundance has declined, primarily due to predation by warmwater nonnative fish and habitat modification following dam construction. Small, reproducing populations remain in the Green and upper Colorado rivers, but their current population trajectory is declining and the San Juan River population is maintained primarily through stocking. As such, establishment of an additional population could aid recovery efforts and increase the species’ resilience and population redundancy. The Colorado River in Grand Canyon once supported Colorado Pikeminnow, but until recently habitat suitability in this altered reach was considered low due to a depressed thermal regime and abundant nonnative predators. Climate change and ongoing drought has presented an opportunity to evaluate the feasibility of native fish restoration in a system where declining reservoir storage has led to warmer releases and re-emergence of riverine habitat. These changes in the physical attributes of the river have occurred in concert with a system-wide decline in nonnative predators. Conditions ten years ago were not compatible with reintroduction feasibility in Grand Canyon; however, due to rapidly changing conditions an expert Science Panel was convened to evaluate whether the physical and biological attributes of this reach could now support various life stages of Colorado Pikeminnow. Here, we report on the evaluation process and outcome from the Science Panel, which developed a science-based recommendation to the U.S. Fish and Wildlife Service on reintroduction feasibility. The Science Panel concluded that current habitat attributes in Grand Canyon could satisfy some, but perhaps not all, Colorado Pikeminnow life history requirements. This reach has the potential to support adult and sub-adult growth, foraging, migrations, and spawning, but low juvenile survival may limit recruitment. However, populations of other native species are successfully reproducing and increasing in western Grand Canyon, even in areas once considered suboptimal habitat. Should managers decide to move to the next phase of this process, actions such as experimental stocking and monitoring, telemetry studies, bioenergetics modeling, and laboratory-based research may provide additional information to further evaluate a potential reintroduction effort in this rapidly changing but highly altered system.

Arizona↗

The diving physiology of bottlenose dolphins (Tursiops truncatus). III. Thermoregulation at depth

During diving, marine mammals initiate a series of cardiovascular changes that include bradycardia and decreased peripheral circulation. Because heat transfer from thermal windows located in peripheral sites of these mammals depends on blood flow, such adjustments may limit their thermoregulatory capabilities during submergence. Here, we demonstrate how the thermoregulatory responses of bottlenose dolphins ( Tursiops truncatus ) are coordinated with the diving response. Heart rate, skin temperature and heat transfer from the dorsal fin and flank were measured while dolphins rested on the water surface, stationed 5–50 m under water and floated at the surface immediately following a dive. The results showed that heat flow ranged from 42.9±7.3 to 126.2±23.1 W m −2 and varied with anatomical site and diving activity. Upon submergence, heat flow declined by 35 % from the dorsal fin and by 24 % from the flank. An immediate increase in heat flow to levels exceeding pre-dive values occurred at both sites upon resurfacing. Changes in heart rate during diving paralleled the thermoregulatory responses. Mean pre-dive heart rate (102.0±2.6 beats min −1 , N =26) decreased by 63.4 % during dives to 50 m and immediately returned to near resting levels upon resurfacing. These studies indicate that heat dissipation by dolphins is attenuated during diving. Rather than challenge the diving response, heat transfer is delayed until post-dive periods when the need for oxygen conservation is reduced.

Journal of Experimental Biology↗

Growth of juvenile steelhead Oncorhynchus mykiss under size-selective pressure limited by seasonal bioenergetic and environmental constraints

Increased freshwater growth of juvenile steelhead Oncorhynchus mykiss improved survival to smolt and adult stages, thus prompting an examination of factors affecting growth during critical periods that influenced survival through subsequent life stages. For three tributaries with contrasting thermal regimes, a bioenergetics model was used to evaluate how feeding rate and energy density of prey influenced seasonal growth and stage-specific survival of juvenile O. mykiss . Sensitivity analysis examined target levels for feeding rate and energy density of prey during the growing season that improved survival to the smolt and adult stages in each tributary. Simulated daily growth was greatest during warmer months (1 July to 30 September), whereas substantial body mass was lost during cooler months (1 December to 31 March). Incremental increases in annual feeding rate or energy density of prey during summer broadened the temperature range at which faster growth occurred and increased the growth of the average juvenile to match those that survived to smolt and adult stages. Survival to later life stages could be improved by increasing feeding rate or energy density of the diet during summer months, when warmer water temperatures accommodated increased growth potential. Higher growth during the summer period in each tributary could improve resiliency during subsequent colder periods that lead to metabolic stress and weight loss. As growth and corresponding survival rates in fresh water are altered by shifting abiotic regimes, it will be increasingly important for fisheries managers to better understand the mechanisms affecting growth limitations in rearing habitats and what measures might maintain or improve growth conditions and survival.

Washington↗

Precise determination of δ 88 Sr in rocks, minerals, and waters by double-spike TIMS: A powerful tool in the study of chemical, geologic, hydrologic and biologic processes

We present strontium isotopic ( 88 Sr/ 86 Sr and 87 Sr/ 86 Sr) results obtained by 87 Sr– 84 Sr double spike thermal ionization mass-spectrometry (DS-TIMS) for several standards as well as natural water samples and mineral samples of abiogenic and biogenic origin. The detailed data reduction algorithm and a user-friendly Sr-specific stand-alone computer program used for the spike calibration and the data reduction are also presented. Accuracy and precision of our δ 88 Sr measurements, calculated as permil (‰) deviations from the NIST SRM-987 standard, were evaluated by analyzing the NASS-6 seawater standard, which yielded δ 88 Sr = 0.378 ± 0.009‰. The first DS-TIMS data for the NIST SRM-607 potassium feldspar standard and for several US Geological Survey carbonate, phosphate, and silicate standards (EN-1, MAPS-4, MAPS-5, G-3, BCR-2, and BHVO-2) are also reported. Data obtained during this work for Sr-bearing solids and natural waters show a range of δ 88 Sr values of about 2.4‰, the widest observed so far in terrestrial materials. This range is easily resolvable analytically because the demonstrated external error (±SD, standard deviation) for measured δ 88 Sr values is typically ≤0.02‰. It is shown that the “true” 87 Sr/ 86 Sr value obtained by the DS-TIMS or any other external normalization method combines radiogenic and mass-dependent mass-fractionation effects, which cannot be separated. Therefore, the “true” 87 Sr/ 86 Sr and the δ 87 Sr parameter derived from it are not useful isotope tracers. Data presented in this paper for a wide range of naturally occurring sample types demonstrate the potential of the δ 88 Sr isotope tracer in combination with the traditional radiogenic 87 Sr/ 86 Sr tracer for studying a variety of biological, hydrological, and geological processes.

Journal of Analytical Atomic Spectrometry↗

Experimental determination of soil heat storage for the simulation of heat transport in a coastal wetland

Two physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32 m diameter by 0.99 m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat–sand–soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed. Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1 cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9 cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6 cm of water and 55.9 cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat–sand–soil mix lags behind maximum solar radiation by approximately 2 h. A slightly longer temperature lag was observed between the maximum solar radiation and maximum water temperature both with and without soil.

Journal of Hydrology↗

Upper thermal limits of growth in brook trout and their relationship to stress physiology

Despite the threat of climate change, the physiological mechanisms responsible for reduced performance at high temperatures remain unclear for most species. Elevated but sublethal temperatures may act via endocrine and cellular stress responses to limit performance in important life-history traits such as growth. Here, brook trout ( Salvelinus fontinalis ) subjected to chronically elevated or daily oscillating temperatures were monitored for growth and physiological stress responses. Growth rate decreased at temperatures above 16°C and was negative at 24°C, with an estimated upper limit for positive growth of 23.4°C. Plasma cortisol increased with temperature and was 12- and 18-fold higher at 22 and 24°C, respectively, than at 16°C, whereas plasma glucose was unaffected by temperature. Abundance of heat shock protein 70 (HSP70) in the gill increased with temperature and was 11- and 56-fold higher at 22°C and 24°C, respectively, than at 16°C. There was no relationship between temperature and plasma Cl − , but there was a 53% and 80% decrease in gill Na + /K + -ATPase activity and abundance at 24°C in comparison with 16°C. Daily temperature oscillations of 4°C or 8°C (19–23°C or 17–25°C) were compared with 21°C controls. Growth rate decreased with temperature and was 43% and 35% lower by length and mass, respectively, in the 8°C daily oscillation treatment than in the controls. There was no effect of temperature oscillation on plasma cortisol or glucose levels. In contrast, gill HSP70 abundance increased with increasing daily oscillation and was 40- and 700-fold greater at 4°C and 8°C daily oscillation, respectively, than in the constant temperature controls. In individuals exposed to 17–25°C diel oscillations for 4 days and then allowed to recover at 21°C, gill HSP70 abundance was still elevated after 4 days recovery, but not after 10 days. Our results demonstrate that elevated temperatures induce cellular and endocrine stress responses and provide a possible mechanism by which growth is limited at elevated temperatures. Temperature limitations on growth may play a role in driving brook trout distributions in the wild.

Journal of Experimental Biology↗

Migration timing and tributary use of spawning flannelmouth sucker (Catostomus latipinnis)

Spawning phenology and associated migrations of fishes are often regulated by factors such as temperature and stream discharge, but flow regulation of mainstem rivers coupled with climate change might disrupt these cues and affect fitness. Flannelmouth sucker (Catostomus latipinnis) persisting in heavily modified river networks are known to spawn in tributaries that might provide better spawning habitat than neighboring mainstem rivers subject to habitat degradation (e.g., embedded sediments, altered thermal regimes, and disconnected floodplains). Passive integrative transponder (PIT) tag data and radio telemetry were used to quantify the timing and duration of flannelmouth sucker tributary spawning migrations in relation to environmental cues in McElmo Creek, a tributary to the San Juan River in the American Southwest. We also tested the extent of the tributary migration and assessed mainstem movements prior to and following tributary migrations. Additionally, multi-year datasets of PIT detections from other tributaries in the Colorado River basin were used to quantify interannual and cross-site variation in the timing of flannelmouth sucker spawning migrations in relation to environmental cues. The arrival and residence times of fish spawning in McElmo Creek varied among years with earlier migration and a three-week increase in residence time in relatively wet years compared to drier years. Classification tree analysis suggested a combination of discharge and temperature determined arrival timing. Of fish PIT tagged in the fall, 56% tagged within 10 km of McElmo Creek spawned in the tributary the following spring, as did 60% of radio-tagged fish, with a decline in its use corresponding to increased distance of tagging location. A broader analysis of four tributaries in the Colorado River basin, including McElmo Creek, found photoperiod and temperature of tributary and mainstem rivers were the most important variables in determining migration timing, but tributary and mainstem discharge also aided in classification success. The largest tributary, the Little Colorado River, had more residential fish or fish that stayed for longer periods (median = 30 days), while McElmo Creek fish stayed an average of just 10 days in 2022. Our results generally suggest that higher discharge, across years or across sites, results in extended use of tributaries by flannelmouth suckers. Conservation actions that limit water extraction and maintain natural flow regimes in tributaries, while maintaining open connection with mainstem rivers may benefit migratory species including flannelmouth suckers.

Journal of Fish Biology↗