Seasonal Temperature Oscillations Research Articles

Temperature and shear-rate effects in two pure clays: Possible implications for clay landslides

Temperature fluctuations in landslide shear zones can originate from heat exchanges with deeper layers as well as with the atmosphere through the landslide body. Shallow landslides (depth <10 m) are especially subject to seasonal temperature oscillations and rapid climatic changes. Various hydro-mechanical properties of clayey soils are sensitive to changes in temperature. Few studies suggested that the residual shear strength may vary significantly even in temperature ranges typical of shallow layers in temperate and warm regions. Here, we verified the response of two pure clays (Ca-bentonite, kaolin) to shearing at temperatures up to ∼55 °C under various normal stresses (50–150 kPa) and shear rates (0.018–44.5 mm/min) by equipping a ring-shear device with a temperature-control system. Then, we performed experiments on an ideal slope to quantify the extent to which ground temperature can condition the stability of clay slopes, across the seasons and under prolonged warming. Considering the largest effects evaluated experimentally (change in residual shear strength by ±1.5 %/°C), we determined changes in global factor of safety by ∼20 % for rotational slides ∼6 m deep, solely attributable to seasonal heating-cooling. Warming of 5 °C over decades would change the stability condition by an additional ±7 %. Although these results were obtained under simplified geometry and boundary conditions, without considering changes in triggers, preconditions, and effects of other thermo-hydro-mechanical couplings, they provide an upper bound to the role of the temperature-dependence of the residual shear strength on the factor of safety. We argue that this role should not be neglected in slope stability and landslide hazard assessments in clay-rich soils, thus warranting in-depth experimental analyses and advanced modelling.

Growth rate rather than temperature affects the B∕Ca ratio in the calcareous red alga &amp;lt;i&amp;gt;Lithothamnion corallioides&amp;lt;/i&amp;gt;

Abstract. The B/Ca ratio in calcareous marine species is informative of past seawater CO32- concentrations, but scarce data exist on B/Ca in coralline algae. Recent studies suggest influences of temperature and growth rates on B/Ca, the effect of which could be critical for the reconstructions of surface ocean pH and atmospheric pCO2. In this paper, we present the first laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of Mg, Sr, Li, and B in the coralline alga Lithothamnion corallioides collected from different geographic settings and depths across the Mediterranean Sea and in the Atlantic Ocean. We produced the first data on putative temperature proxies (Mg/Ca, Li/Ca, Sr/Ca, Mg/Li) and B/Ca in a coralline algal species grown in different basins from across the photic zone (12, 40, 45, and 66 m depth). We tested the B/Ca correlation with temperature proxies and growth rates in order to evaluate their possible effect on B incorporation. Our results suggested a growth rate influence on B/Ca, which was evident in the sample with the lowest growth rate of 0.10 mm yr−1 (Pontian Isl., Italy; 66 m depth) and in Elba (Italy; 45 m depth), where the algal growth rate was the highest (0.14 mm yr−1). At these two sites, the measured B/Ca was the lowest at 462.8 ± 49.2 µmol mol−1 and the highest at 757.7 ± 75.5 µmol mol−1, respectively. A positive correlation between B/Ca and temperature proxies was found only in the shallowest sample from Morlaix (Atlantic coast of France; 12 m depth), where the amplitude of temperature variation (ΔT) was the highest (8.9 ∘C). Still, fluctuations in B/Ca did not mirror yearly seasonal temperature oscillations as for Mg/Ca, Li/Ca, and Sr/Ca. We concluded that growth rates, triggered by the different ΔT and light availability across depth, affect the B incorporation in L. corallioides.

Forecast of Thermal Mode for the Slope Fill-Up Ground, Considering the Operation of Seasonal Cooling Units in Cryolithic Zone Conditions

The article is concerned with the solution of the issue of freezing and stabilization of negative thermal mode for the slopes made of fill-up ground, which are held by a gabion wall in cryolithic zone conditions. To estimate the efficiency of artificial freezing of the slope ground, a mathematical 3D model of heat-exchange processes was worked out, which takes into account the phase change of moisture, freezing temperature, length of cooling devices, their quantity and location, the annual cycle of ambient air temperature and ground bedding. The model takes into account geometrical parameters of the slope and impact of daylight surface. The issue had been solved with numerical technique of finite differences. The calculations indicated the efficiency of implementation of seasonal cooling units for increasing of the fill-up slope stability. Their implementation results in progressive accumulation of cold in its ground. By the end of the fourth year of freezing, the whole mass of the fill-up slope ground turns into a frozen state. When seasonal cooling units were switched off in next years, the frozen area in the fill-up slope remains the same and thermal mode of the slope ground becomes a stable periodic cycle, i.e. expected seasonal temperature oscillations take place.

Rock Glacier Dynamics by a Thermo-Elastic-Viscoplastic Constitutive Relationship

As a result of mountain permafrost creep, rock glaciers are common features in high-altitude periglacial areas. From a practical point of view, beyond their localization and inventorying, both the monitoring and prediction of their evolution due to climate changes are crucial. One of the effects of climate change is the thickening of the basal shear zone (the portion of the rock glacier where most deformations are localized), eventually leading to the development of unexpected and unprecedented (in terms of location, magnitude, frequency, and timing) instability phenomena. These phenomena bear consequences for the understanding of landscape evolution, natural hazards, and the safe and sustainable operation of high-mountain infrastructures. Most of the studies about active rock glaciers are focused on the analysis of monitoring data, while just a few studies are focused on modeling their behavior to understand their possible further evolution. The active rock glacier response is characterized by a viscous (rate-dependent) behavior, influenced by seasonal temperature oscillations, and characterized by a seasonal transition from slow to fast. In this work, a new thermo-mechanical model based on the delayed plasticity theory and calibrated on experimental results is proposed. The model is employed to evaluate the influence of geometry and forcing (air temperature) on a real rock glacier (Murtèl-Corvatsch rock glacier) creep behavior.

Seasonal bedrock temperature oscillations and inversions as a function of depth and the implications for thermal fatigue

ABSTRACT Research was undertaken to assess the influence of aspect and sub-surface depth on thermal fatigue in bedrock. Contact temperatures were recorded at depths of 0.3 m, 2.0 m and 6.0 m in boreholes drilled on three aspects of a tillite outcrop from mid-winter to mid-summer. Results showed that seasonal temperature oscillations of up to 20 ºC occurred in bedrock and that heat dissipation and build-up do not commence or cease at the same time throughout the rock mass, conceptually resulting in lateral and vertical thermal strain. Critically, thermal fatigue at depth may induce micro-cracking in bedrock, well before surface-related weathering processes or mechanisms commence.

Seasonal Temperature Oscillations Drive Contrasting Arsenic and Antimony Mobilization in a Mining‐Impacted River System

AbstractArsenic (As) and antimony (Sb) speciation and mobility in river systems can be influenced by the redox conditions of benthic and hyporheic zone sediments. However, our understanding of how temperature fluctuations influence riverine As and Sb mobility over diel and seasonal time frames, via moderation of sediment redox conditions, is poorly constrained. Here we compare diel and seasonal water quality data from a river system contaminated with As and Sb with results from sediment‐water incubations conducted at temperatures spanning 8°C to 32°C under low‐dissolved oxygen conditions. Higher incubation temperatures caused faster microbial respiration, lower redox potential, and greater Asaq concentrations, coincident with reduction of As(V), Mn (III/IV), Fe (III), and SO42−. Initial rates of As3+aq formation increased exponentially with temperature (Q10 = 3.3 ± 0.5) and were positively correlated with microbial respiration (r2 = 0.99, P &lt; 0.01). In contrast, Sbaq displayed an initially negative and comparatively weak overall temperature dependence during incubations. In river waters, diel mobilization of reduced species (As3+aq and Fe2+aq) and contrasting attenuation of Sb was coincident with lower redox potential during nightly respiration cycles. Distinct seasonal oscillations in river water Asaq were exponentially correlated with temperature (r2 = 0.68, P &lt; 0.01), whereas Sbaq was not. These characteristics reflect the fundamental role of anaerobic metabolism (as influenced by temperature) within benthic and hyporheic zone sediments as a key driver of contrasting riverine As and Sb mobility. The findings imply that riverine As mobility may be enhanced, while Sb mobility possibly attenuated, by eutrophication or by elevated stream temperatures due to a warming climate.

Modelling methane hydrate stability changes and gas release due to seasonal oscillations in bottom water temperatures on the Rio Grande cone, offshore southern Brazil

Abstract The stability of methane hydrates on continental margins worldwide is sensitive to changes in temperature and pressure conditions. It has been shown how gradual increases in bottom water temperatures due to ocean warming over post-glacial timescales can destabilize shallow oceanic hydrate deposits, causing their dissociation and gas release into the ocean. However, bottom water temperatures (BWT) may also vary significantly over much shorter timescales, including due to seasonal temperature oscillations of the ocean bottom currents. In this study, we investigate how a shallow methane hydrate deposit responds to seasonal BWT oscillations with an amplitude of up to 1.5 °C. We use the TOUGH + HYDRATE code to model changes in the methane hydrate stability zone (MHSZ) using data from the Rio Grande Cone, in the South Atlantic Ocean off the Brazilian coast. In all the cases studied, BWT oscillations resulted in significant gaseous methane fluxes into the ocean for up to 10 years, followed by a short period of small fluxes of gaseous methane into the ocean, until they stopped completely. On the other hand, aqueous methane was released into the ocean during the 100 years simulated, for all the cases studied. During the temperature oscillations, the MHSZ recedes continuously both horizontally and, in a smaller scale, vertically, until a permanent and a seasonal region in MHSZ are defined. Sensitivity tests were carried out for parameters of porosity, thermal conductivity and initial hydrate saturation, which were shown to play an important role on the volume of methane released into the ocean and on the time interval in which such release occurs. Overall, the results indicate that in a system with no gas recharge from the bottom, seasonal temperature oscillations alone cannot account for long-term gas release into the ocean.

Environmental Factors Controlling the 13C and 18O Variations of Recent Fluvial Tufas: A 12-Year Record from the Monasterio de Piedra Natural Park (Ne Iberian Peninsula)

Abstract A 12-year study (2000–2012) of the stable isotopes of recent fluvial tufas has been performed in the Monasterio de Piedra Natural Park (River Piedra, NE Iberian Peninsula), an area of Mediterranean climate with intense tufa deposition since the Pleistocene. The biannual monitoring of the tufa calcite δ13C and δ18O signatures and of the water δ18O value has demonstrated a clear seasonal pattern for the tufa-calcite oxygen isotope composition, with less negative values for cool periods, which is consistent with regional temperature oscillations. The tufa calcite δ13C values only occasionally exhibit a pattern, which is inconclusive and opposite to the δ18O clear pattern. The water δ18O signature has a distinct seasonal pattern, also opposite to the tufa-calcite δ18O clear pattern. The temperature calculations from the tufa-calcite δ18O values and average water δ18O values agree with the seasonal pattern of measured water temperatures, with a mean difference of 2.3 °C between the calculated and measured temperatures. The anomalous values recorded for both the water and the tufa-calcite oxygen isotope composition during a two-year period are characterized by smoothing of the seasonal variations of the tufa calcite and by reversal of the water pattern. There is also an increase in the differences between the measured and estimated temperatures. The detected anomaly is roughly synchronous with a change in the isotopic signature of the regional precipitation δ18O values. This contribution demonstrates that tufas in this depositional and climatic context are good indicators of seasonal temperature oscillations, and that tufas can also record other interannual environmental changes such as variations in the isotopic composition of precipitation. These results can be extrapolated to ancient tufa systems developed in similar contexts, which would expand the potential of tufas as high-resolution records of paleoenvironmental conditions.

Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 441:141-149 (2011) - DOI: https://doi.org/10.3354/meps09399 Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences Ester Canali1, Giovanna Ponte1,*, Paola Belcari2,3, Francisco Rocha4, Graziano Fiorito1 1Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy 2Dipartimento di Scienze dell’Uomo e dell’Ambiente, University of Pisa, 56126 Pisa, Italy 3London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, UK 4Department of Ecology and Animal Biology, University of Vigo, Campus of Lagoas-Marcosende, 36310 Vigo, Spain *Email: giovanna.ponte@szn.it ABSTRACT: Several internal structures have been used to estimate age in the cephalopod Octopus vulgaris, but with limited accuracy. We estimated age by investigating growth increments (rings) in the upper beaks of octopus collected between 2003 and 2010 in the Bay of Naples, Italy (Mediterranean Sea). To validate the daily periodicity of ring deposition, ‘thermal shock marking’ was for the first time applied to live octopuses fished between 2009 and 2010; this method produced a mark on the beak corresponding to the day of thermal shock, enabling us to elucidate the relationship between ring number and time elapsed (i.e. ~30 d). In addition, rings were counted in >700 preserved specimens of O. vulgaris collected between 2003 and 2009, also in the Bay of Naples. The estimated age of of these octopuses ranged from about 70 to 370 d. Specimens with similar body weights had different numbers of rings, confirming the view that body size is a not a good index of age. Additionally, the relationship between body weight and number of rings was affected by sex and season, with the distance between rings clearly correlated to seasonal temperature oscillations. Our data suggest that different cohorts of octopus exist in the Bay of Naples and that temperature has a strong influence on growth. Overall the results demonstrate that growth increments in the upper beak of O. vulgaris provide a reliable method of aging that can be applied to assessing differences in the growth patterns in wild populations, and one that provides a record of environmental influences upon an individual. KEY WORDS: Octopus · Age · Thermal marking · Upper beak · Seasonal variability Full text in pdf format PreviousNextCite this article as: Canali E, Ponte G, Belcari P, Rocha F, Fiorito G (2011) Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences. Mar Ecol Prog Ser 441:141-149. https://doi.org/10.3354/meps09399 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 441. Online publication date: November 15, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Moisture source temperatures and precipitation δ18O‐temperature relationships across the United States

Understanding and modeling precipitation isotope (δ18O and δD) patterns for large regions of the globe requires quantifying processes governing continental‐scale climatology and hydrology. In this study, we have evaluated the extent to which inclusion of monthly moisture source temperature and moisture source locations in the Rayleigh distillation model aid in reproducing the relationships between monthly time series of precipitation isotope (δ18O) values and temperature across the contiguous United States. The steepest isotope‐temperature slopes (0.5‰–0.6‰ δ18O/°C) and greatest δ18O value correlations with temperature (r2 = 0.5–0.8), derived from 5 continuous years of the data from the United States Network for Isotopes in Precipitation, occurred in the high altitudes of the Rocky Mountains and the upper Great Lakes region. The isotope‐temperature slopes derived from the site‐specific time series were consistently lower along the coastal regions of the United States as were the coefficients of determination. The low coastal isotope‐temperature slopes are not easily explained by the simple Rayleigh model that uses condensation temperatures as the primary driver of precipitation isotopes. However, the Raleigh model equipped with moisture source temperatures defined by seasonal temperature oscillations and migrating moisture source locations provides a robust replication of the δ18O‐temperature slopes along coastal regions. These findings emphasize the importance of moisture sources conditions when interpreting palaeoclimate proxies (i.e., tree rings, ice cores, etc.), and argue that moisture source dynamics should always be included in models that use isotopes as diagnostic tools in testing hydrologic models.

Diurnal Habitability of Frozen Worlds

In this work we discuss effects allowing local habitability of some extraterrestrial planets of low average surface temperatures. We analyze the problem of diurnal and seasonal changes of temperature and biological productivity at different locations on a hypothetical Earth-like planet. We have found, that under some circumstances the temperature may locally rise well above the average value, allowing periods of enhanced biological activity. In this way, bioproductivity can become periodically possible on a planet that has an average temperature clearly below 0°C. Such thermal conditions are encountered on Mars (Smith et al. in Science 306:1750–1753, 2004) generally considered as inhabitable. In reality, an appropriate temperature is not sufficient for habitability. The presence of liquid water at the considered location is also necessary. We discuss how temperature oscillations affect habitability in the framework of a conceptual model. We find that the considered effect of diurnal and seasonal temperature oscillations can extend the outer boundary of the habitable zone up to 2 AU, while global average temperatures are below 0°C for heliocentric distances R h > 1.12 AU (dry atmosphere, low CO2 pressure), or R h > 1.66 AU (humid atmosphere, high CO2 pressure).

Modelling the effect of temperature on hatching and settlement patterns of meroplanktonic organisms: the case of octopus

The duration of embryonic development and the planktonic stage of meroplanktonic species is highly temperature dependent and thus the seasonal temperature oscillations of temperate regions greatly affect the patterns of hatching and benthic settlement. Based on data from the literature on embryonic development and planktonic duration of Octopus vulgaris (common octopus) in relation to temperature, and on observed temperature patterns, several models of hatching and settlement patterns were created. There was a good fit between observed settlement patterns and model predictions. Based on these models we concluded that in temperate regions: (1) when temperature is increasing (from early spring to mid summer) the hatching and settlement periods tend to shorten, while when the temperature is decreasing (during autumn) the hatching and settlement periods tend to lengthen; (2) hatching and settlement peaks are narrower and more intense than a spring spawning peak but wider and less intense than an autumn spawning peak; (3) at lower latitudes, hatching and settlement patterns tend to follow the spawning pattern more closely, (4) the periodic temperature pattern of temperate areas has the potential to cause a convergence of hatching during spring.

Geographic variations in the thermal and diffusive stability of ground ice on Mars

To investigate the stability of ground ice within the top several meters of the Martian regolith, time‐dependent models of the thermal and diffusive behavior of the regolith have been developed. The geographic distribution of thermal inertia and albedo as well as the latitudinal variation in insolation have been included in calculations of surface and subsurface temperatures between ±60° latitude. Ground ice was found to be stable where the annual mean surface and subsurface temperatures were below the atmospheric frost point. This generally occurs poleward of the mid‐latitudes. The latitude poleward of which ground ice is stable varies by about 20° to 30° from one longitude to another. Geographic variations in thermal inertia and albedo are the primary factors controlling regional variations in ice stability. Calculations of temperatures at high and low obliquity suggest that ground ice would be stable globally at high obliquity and would not be stable between ±60° latitude at low obliquity. Thermally driven diffusion of atmospheric water vapor within the regolith was modeled accounting for both ordinary molecular and Knudsen transport and equilibrium between ice, vapor, and adsorbed phases. Atmospheric water vapor was found to be able to supply the top few meters of the regolith with ice in regions where the annual mean surface temperature was below the atmospheric frost point. Ice was found to begin condensing in as short as 1000 Martian years. Rapid accumulation of ice in the pore space of the upper layers of the regolith acted to choke transport to lower layers and slow the diffusion process. Even so, after 105 Martian years, in some cases, as much as 30% to 40% of the available pore space accumulated ice. The total amount of subsurface ice ranged from a few to more than 25 g/cm2 within the top few meters in regions of stability. Ground ice was found to form below a depth where the annual average vapor pressure over ice was equal to the annual average atmospheric vapor pressure near the surface. Atmospheric vapor was not found to accumulate as ice below a depth where the seasonal temperature oscillations gave way to the geothermal gradient. The time scales for condensation of ground ice were found to be comparable to that of orbital oscillations suggesting that the present geographic distribution of ground ice may depend on the orbital history of Mars.

Seasonal Temperature Effects on a Foundation

During the construction of a large chimney at the Porto Tolle power station, a settlement-monitoring program disclosed unusual yet periodic deflections in the performance of the pile-supported concrete foundation, in addition to the expected settlements due to soil consolidation. A special monitoring program using embedded thermocouples revealed that the deflections were seasonal and related to thermal gradients in the soil-foundation system. It is concluded that in some cases stresses caused by seasonal temperature oscillations should be considered in the design phase of foundations. A simple heat transfer analysis is applied which can be used to estimate the highest temperature gradient to be expected.

Displacement registration of sandstone blocks in the Stolowe Gory mountains, Poland

A local geodetic observation of block displacements in the Szczeliniec Massif was started in 1972, and later was supplemented by an exact fissure dilatation measurement and extended to cover the whole massif. Special instrumentation has been used and a three-dimensional observation system has been developed. Results reveal fluctuating displacements that can be, to some extent, explained by seasonal temperature oscillations. It is intended to continue the observations to acquire more specific results, since the present results cannot be definitely interpreted in favour of slope movements of blocks due to creep in the bed, which was anticipated.