Seasonal Swings Research Articles

Seasonal Swings and Graphical Tale of Growth and Productivity of Wheat in Gujarat State in Comparison with National Market (India)

This study comprehensively analyzes the growth and variability in the area, production, and productivity of wheat, a staple food grain in Gujarat state, India, for the period 2001-2022. Wheat holds significant importance in India's agricultural landscape, being one of the staple crops vital for food security. Gujarat, known for its diverse agro-climatic conditions, plays a pivotal role in contributing to the nation's wheat production. Understanding the seasonal dynamics, growth patterns, and productivity trends of wheat in Gujarat which is the broader national market provides valuable insights into the agricultural dynamics of the region. Utilizing exponential fitting and statistical regression techniques, the research presents compound growth rates for India and Gujarat, revealing significant positive correlations between wheat cultivation area, production, and productivity. Graphical representations depict trends and fluctuations, highlighting periods of deviation from trend lines. Instability analyses for India and Gujarat shed light on the consistency and fluctuations in wheat cultivation, production, and productivity. Additionally, the study explores seasonal variations in wheat prices across markets in Gujarat, providing insights into intra-year price cycles and coefficient variations. The findings contribute valuable insights into the dynamics of wheat agriculture in Gujarat, offering implications for policy and agricultural practices.

Evolution and driving mechanisms of water circulation during the late Paleozoic to early Mesozoic

<p indent="0mm">Water circulation plays a crucial role in the Earth’s systems, linking the atmosphere, hydrosphere, lithosphere, and biosphere. During the Paleozoic-Mesozoic transition, climatic and environmental conditions turned into crises, caused by a sudden and serious global warming, accompanied by the largest known extinction event of all time. Several studies have been conducted to discover the causes of this notable climate change. Nevertheless, the evolution of water circulation processes during the Paleozoic-Mesozoic transition is still unclear. Several lithologic indicators present in paleoclimate records have been described over the last few decades. Based on these data, we defined climate zones and calculated their area values using Thiessen polygons and Geographic Information System technology to visualize climate evolution during the Paleozoic-Mesozoic transition. Results of a few of the climate simulations showed changes in precipitation and the amplitudes of the inter-tropical convergence zone (ITCZ) seasonal migration. The results showed several changes in water circulation during the late Paleozoic to early Mesozoic. (1) The climate zones reconstructed by sedimentary and paleontological records showed a remarkable arid expansion. The distribution area of evaporites began to expand in the Middle to Late Permian and reached a peak in the Early Triassic, returned to Middle-Late Permian levels in the Middle Triassic, and thereafter continued to narrow during the Late Triassic to Early Jurassic. (2) Global precipitation was higher during the Late Carboniferous and Early Jurassic and lower in the Middle to Late Permian and Early Triassic. Such a “V” shape represents considerable swing. (3) The assembly of Pangea might have led to “giant land surface winds” in Pangaea and “trans-equatorial winds” in the Tethys region, resulting in a global “megamonsoon”. (4) Seasonal movements of the ITCZ were located at lower latitudes from the Silurian to Carboniferous and from the Jurassic to the present, while reaching higher latitudes with large seasonal oscillations during the Permian-Triassic. Depending on the timing of events, these major changes in water circulation coincided with the assembly of Pangaea, the Variscan or Hercynian orogeny, the end of the late Paleozoic ice age, major carbon emissions, and global warming. These factors are closely related to the changes in atmospheric and water circulation during the Paleozoic-Mesozoic transition. The assembly of Pangea redistributed water storage and altered atmospheric circulation and the “megamonsoon”, while the elevation reduction of mountains traversing middle Pangea weakened the resistance of north and south winds. These factors promoted the evolution of a “megamonsoon” with strong seasonal swings of the ITCZ, which led to the expansion of arid zones and reduced precipitation during the Middle and Late Permian. Meanwhile, large carbon emissions and dramatic global warming altered the energy transition within global systems, which influenced atmospheric circulation. In addition, transformations of global plant clades affected the carbon budget and altered water circulation. In summary, strong fluctuations in water circulation were present during the Paleozoic-Mesozoic transition, especially as observed through climate zones, precipitation and runoff, the “monsoon”, and ITCZ. These crucial processes reflect the interaction between the lithosphere, atmosphere, hydrosphere, and biosphere. However, we have limited knowledge of the complete process of water circulation because geological records and climate simulations are extremely imprecise for the Paleozoic-Mesozoic transition. Future research could focus on other water circulation processes, such as the evolution of underground water, reserves, and fluxes of lakes, rather than only precipitation and “monsoons”. Moreover, the upgrade and extension of big data platforms and a larger number of climate simulations should be considered in future studies.

Stable isotope and geochemical evidence for genesis of secondary copper deposits at Girilambone, New South Wales, Australia

AbstractThe Girilambone copper deposit of New South Wales, Australia, serves as an end-member model for development of a classic oxidation-zone profile in an environment virtually free of both the effects of active tectonics and significant fluctuation in the local water table. The oxidation zone of other copper deposits may be interpreted for history of recently active tectonics, palaeoclimate, and water-table stability by comparison to the Girilambone deposit. Unlike the oxidation profiles of porphyry copper deposits of western North America, which have been overprinted by many water-table fluctuations produced by active tectonics, the Girilambone deposit appears to have little modification to the original oxidation profile. Oxidation of primary sulfides at Girilambone was an exothermic process facilitated by chemolithotrophic bacteria, recorded by malachite oxygen isotope thermometry estimates of up to 52°C, and very light malachite carbon isotope values. The bacteria generated CO2 which migrated upwards to react with copper rich meteoric fluids of the vadose zone to precipitate malachite. Unlike porphyry copper deposits of western North America which experienced recent tectonic activity, the secondary minerals (clays, iron oxides and copper carbonates) at Girilambone were not repeatedly fractured and offset during oxidation to re-establish permeability. This reduced permeability of the oxidation zone and slowed the release of CO2 from the system, producing significantly elevated partial pressure of CO2, sufficient for azurite formation to dominate. Azurite oxygen and carbon isotope values indicate formation at lower temperatures up to 32°C, and with less bacterial activity than for malachite. The sulfide-digesting bacteria at Girilambone were relatively free of seasonal swings in population, as the deposit does not have the interbanded azurite and malachite typical of episodic bacterial populations triggered by seasonal precipitation. Thus the absence of significant Cu-carbonate banding at Girilambone serves as a palaeoclimate indicator. Deeper in the Girilambone oxidation zone, native copper and cuprite dominate, whereas chalcocite formed an enrichment blanket just above and at the modern water table. Oxygen and carbon isotope values for pseudomorphs of malachite after azurite indicate that these were generated as a retrograde reaction when CO2 production from bacterial digestion of sulfides waned and temperatures in the oxidation zone were near ambient. In the post mining environment, chloride-rich groundwater seeps actively precipitate atacamite, while exposed remnants of sulfide masses form an outer rind of porous malachite. Exceptions to this oxidation zone sequence occur due to localised fluid channelisation and perched water-table lenses that generated mineralogical overprints.

Accurate Simulation of Both Sensitivity and Variability for Amazonian Photosynthesis: Is It Too Much to Ask?

Estimates of Amazon rainforest gross primary productivity (GPP) differ by a factor of 2 across a suite of three statistical and 18 process models. This wide spread contributes uncertainty to predictions of future climate. We compare the mean and variance of GPP from these models to that of GPP at six eddy covariance (EC) towers. Only one model's mean GPP across all sites falls within a 99% confidence interval for EC GPP, and only one model matches EC variance. The strength of model response to climate drivers is related to model ability to match the seasonal pattern of the EC GPP. Models with stronger seasonal swings in GPP have stronger responses to rain, light, and temperature than does EC GPP. The model to data comparison illustrates a trade‐off inherent to deterministic models between accurate simulation of a mean (average) and accurate responsiveness to drivers. The trade‐off exists because all deterministic models simplify processes and lack at least some consequential driver or interaction. If a model's sensitivities to included drivers and their interactions are accurate, then deterministically predicted outcomes have less variability than is realistic. If a GPP model has stronger responses to climate drivers than found in data, model predictions may match the observed variance and seasonal pattern but are likely to overpredict GPP response to climate change. High or realistic variability of model estimates relative to reference data indicate that the model is hypersensitive to one or more drivers.

Modelling seasonal mortality with individual data

Most studies of seasonal variation in mortality rely on aggregated death counts at population level. In this paper, we use individual data to present a series of models for different aspects of seasonal variation. The models are fitted to a variety of international pensioner data sets and suggest a high degree of commonality across countries with different climates and different health systems. The power of individual life-history survival modelling allows the detection of seasonal patterns in even modest-sized portfolios. We measure the tendency for seasonal fluctuations to increase with age, and we again find strong similarities between geographically distinct populations. We further find that seasonal effects are generally uncorrelated with gender, but that low-income pensioners can suffer greater seasonal swings than high-income ones. Finally, we propose a single-parameter measure for the extent to which winter mortality is a spike and summer mortality is a shallower trough, and show results for a variety of data sets.

Vertical stratification collapses under seasonal shifts in climate

AbstractAimTropical forests are vertically complex, and offer unique niche opportunities in the form of climate, habitat and resource gradients from ground to canopy. Rainforest species organize within this vertical spatial gradient and recent macroecological research suggests that the highest levels of vertical stratification occur in structurally complex and climatically stable tropical rainforests. However, although the classical view of the tropics is that of aseasonality, particularly in temperature, there is strong seasonality in rainfall. Thus, we predict considerable variation in vertical stratification in time, characterized by a seasonal restructuring of communities across vertical space.LocationSierra Llorona, Colón Province, Panama.TaxonAmphibians.MethodsWe performed 121 ground‐to‐canopy surveys across the wet and dry seasons for amphibians. Using a bootstrap simulation method we calculated species‐specific and community‐wide vertical height and abundance shifts between seasons. Separately, we tested the importance of vertical height and season on the vertical distribution of species using a redundancy analysis, and employed linear models to explore turnover in species composition across vertical height between seasons.ResultsOur results show a clear downward shift of 5 m in height in amphibian communities from the wet season to dry season. We also observe significant changes in species composition across vertical strata in both seasons, driven primarily by nestedness in the dry season (loss of species over height) and genuine turnover in the wet season (loss and addition of species over height).Main conclusionsThe exploitation of canopy microhabitats and resources in the wet season resulted in complex patterns of stratification, whereas drying flattened the distribution and simplified the composition of arboreal communities. As such, pattern and process in the vertical dimension is not static in time but rather exists as a dichotomy with inverse patterns between wet and dry seasons. Complex, multidimensional distributions of diverse rainforest communities can be simplified by climatic constraints – an important consideration as anthropogenic climate change increases the magnitude of seasonal swings in temperature and precipitation.

Mississippi river sediment diversions and coastal wetland sustainability: Synthesis of responses to freshwater, sediment, and nutrient inputs

Management and restoration of coastal wetlands require insight into how inundation, salinity, and the availability of mineral sediment and nutrients interact to influence ecosystem functions that control sustainability. The Mississippi River Delta, which ranks among the world's largest and most productive coastal wetland complexes, has experienced extensive deterioration over the last century due, in large part, to enhanced vulnerability to relative sea-level rise and lateral erosion caused by a combination of natural processes and anthropogenic modifications of hydrology. This land loss crisis has prompted the State of Louisiana to develop a comprehensive restoration plan that includes constructing and implementing a series of large-scale sediment diversions that will reconnect sediment- and nutrient-rich Mississippi River water to adjacent bays, estuaries, and wetlands. Sediment loading through diversions is predicted to enhance the long-term sustainability of coastal wetlands; however, the additive effects of increased inundation, abrubt changes in the salinity regime, and high nutrient loads on wetland plant growth and organic matter (SOM) decomposition rates, which help regulate accretion and elevation change, is uncertain. Therefore, this review attempts to synthesize existing information to inform predictions of the interactive effects of diversions on these drivers of coastal wetland sustainability. The data suggest that sediment deposition within an optimal elevation range will increase the overall productivity of existing wetlands where prolonged flooding does not counter this effect by limiting plant growth. A reduction in salinity may increase plant productivity and cause vegetation shifts to less salt tolerant species, but seasonal swings in salinity may have unforeseen consequences. Nutrient-loading is predicted to lead to greater aboveground productivity, which, in turn, can facilitate additional sediment trapping; however, belowground productivity may decline, particularly in areas where sediment deposition is limited. In areas experiencing net deposition, nutrient-enrichment is predicted to enhance belowground growth into new sediment and contribute to positive effects on soil organic matter accumulation, accretion, and elevation change. Thus, we contend that sediment input is essential for limiting the negative effects of flooding and nutrient-enrichment on wetland processes. These conclusions are generally supported by the biophysical feedbacks occurring in existing prograding deltas of the Mississippi River Delta complex.

Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

Abstract. In this study, we characterize the transport of ozone from Africa to Asia through the analysis of the simulations of a global chemical transport model, GEOS-Chem, from 1987 to 2006. The receptor region Asia is defined within 5–60∘ N and 60–145∘ E, while the source region Africa is within 35∘ S–15∘ N and 20∘ W–55∘ E and within 15–35∘ N and 20∘ W–30∘ E. The ozone generated in the African troposphere from both natural and anthropogenic sources is tracked through tagged ozone simulation. Combining this with analysis of trajectory simulations using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, we find that the upper branch of the Hadley cell connects with the subtropical westerlies in the Northern Hemisphere (NH) to form a primary transport pathway from Africa to Asia in the middle and upper troposphere throughout the year. The Somali jet that runs from eastern Africa near the equator to the Indian subcontinent in the lower troposphere is the second pathway that appears only in NH summer. The influence of African ozone mainly appears over Asia south of 40∘ N. The influence shows strong seasonality, varying with latitude, longitude, and altitude. In the Asian upper troposphere, imported African ozone is largest from March to May around 30∘ N (12–16 ppbv) and lowest during July–October around 10∘ N (∼ 2 ppbv). In the Asian middle and lower troposphere, imported African ozone peaks in NH winter between 20 and 25∘ N. Over 5–40∘ N, the mean fractional contribution of imported African ozone to the overall ozone concentrations in Asia is largest during NH winter in the middle troposphere (∼ 18 %) and lowest in NH summer throughout the tropospheric column (∼ 6 %). This seasonality mainly results from the collective effects of the ozone precursor emissions in Africa and meteorology and chemistry in Africa, in Asia and along the transport pathways. The seasonal swing of the Hadley circulation and subtropical westerlies along the primary transport pathway plays a dominant role in modulating the seasonality. There is more imported African ozone in the Asian upper troposphere in NH spring than in winter. This is likely due to more ozone in the NH African upper troposphere generated from biogenic and lightning NOx emissions in NH spring. The influence of African ozone on Asia appears larger in NH spring than in autumn. This can be attributed to both higher altitudes of the elevated ozone in Africa and stronger subtropical westerlies in NH spring. In NH summer, African ozone hardly reaches Asia because of the blocking by the Saharan High, Arabian High, and Tibetan High on the transport pathway in the middle and upper troposphere, in addition to the northward swing of the subtropical westerlies. The seasonal swings of the intertropical convergence zone (ITCZ) in Africa, coinciding with the geographic variations of the ozone precursor emissions, can further modulate the seasonality of the transport of African ozone, owing to the functions of the ITCZ in enhancing lightning NOx generation and uplifting ozone and ozone precursors to upper layers. The strength of the ITCZ in Africa is also found to be positively correlated with the interannual variation of the transport of African ozone to Asia in NH winter. Ozone from NH Africa makes up over 80 % of the total imported African ozone over Asia in most altitudes and seasons. The interhemispheric transport of ozone from southern hemispheric Africa (SHAF) is most evident in NH winter over the Asian upper troposphere and in NH summer over the Asian lower troposphere. The former case is associated with the primary transport pathway in NH winter, while the latter case is associated with the second transport pathway. The intensities of the ITCZ in Africa and the Somali jet can each explain ∼ 30 % of the interannual variations in the transport of ozone from SHAF to Asia in the two cases.

Classified model and characteristics of strategies at tourist companies

The research is devoted to the assessment of the scientific approaches to the identification of classification features of the strategy and its types distinguished in accordance with the mentioned features. The research object is the activities of tourist companies and this determines the choice of strategies typical for the tourism field. It is substantiated that the scientific approaches to the classification of strategies are various in specific literature because of obscurity in the strategy definition, vagueness and plurality of its classified features. Due to the current research the authors have improved the classified model of strategies for tourist companies that will result in making effective management decisions directed to the development of enterprise potential under conditions of unstable and unpredictable external environment. The paper singles out the peculiarities of functioning the tourism branch, which are the following : high sensitivity to the changes in external environment; the high level of competition in the field; dynamics and the lack of necessity for the use of «far-seeing» strategies; insufficiency of information provision for the application of traditional western models and matric methods of strategy development; time gap between obtaining the service and its consumption; a great number of intermediaries; seasonal swings in demands; the sudden shift of external environment caused by cyclicity, globalization, political decisions of separate countries and etc. The article shows essential differences in the development of financial strategies of small-scale enterprises and stock companies of tourist business. It is substantiated that small-scale enterprises develop strategies directed to a higher level of personal services, occupational competence, ability and experience in designing, the best knowledge of regional conditions and flexible decisions caused by the peculiarities of the received orders. Taking into account the peculiarities of functioning tourist companies of small- and middle-scale business, and according to the classification proposed, the author suggests the following priority in strategies: the 1-st priority is focusing on differentiation; the 2-nd priority is differentiation; the 3-d priority is focusing on expenditures; the 4-th priority is the leadership according to the expenditures.

Effect of Seasonal Swings and Age Specific Variations on Body Weight of Indian Gerbille (Tatera indica)

Effect of Seasonal Swings and Age Specific Variations on Body Weight of Indian Gerbille (Tatera indica)

Assessing the potential of sun-induced fluorescence and the canopy scattering coefficient to track large-scale vegetation dynamics in Amazon forests

Two new remote sensing vegetation parameters derived from spaceborne spectrometers and simulated with a three dimensional radiative transfer model have been evaluated in terms of their prospects and drawbacks for the monitoring of dense vegetation canopies: (i) sun-induced chlorophyll fluorescence (SIF), a unique signal emitted by photosynthetically active vegetation and (ii) the canopy scattering coefficient (CSC), a vegetation parameter derived along with the directional area scattering factor (DASF) and expected to be particularly sensitive to leaf optical properties. Here, we present the first global data set of DASF/CSC and examine the potential of CSC and SIF for providing complementary information on the controversially discussed vegetation seasonality in Amazon forests. A comparison between near-infrared SIF derived from the Global Ozone Monitoring Experiment-2 (GOME-2) instrument and the Orbiting Carbon Observatory-2 (OCO-2) (overpass time in the morning and noon, respectively) reveals the response of SIF to instantaneous photosynthetically active radiation (PAR). Large-scale seasonal swings of GOME-2 SIF amount up to 21% (regarding the annual maximum) and peak in October and around February, while OCO-2 SIF peaks in February. However, both time series agree very well if SIF is normalized by overpass time and wavelength. We further examine anistropic reflectance characteristics with the finding that the hot spot effect significantly impacts observed GOME-2 SIF values. On the contrary, our sensitivity analysis suggests that CSC is highly independent of sun-sensor geometry as well as atmospheric effects. The slight annual variability of CSC (3%) shows no clear seasonal cycle, while a relatively high spatial standard deviation points to a high degree of spatial heterogeneity in our study domain within the central Amazon Basin.

Selenium Speciation in the Fountain Creek Watershed (Colorado, USA) Correlates with Water Hardness, Ca and Mg Levels.

The environmental levels of selenium (Se) are regulated and strictly enforced by the Environmental Protection Agency (EPA) because of the toxicity that Se can exert at high levels. However, speciation plays an important role in the overall toxicity of Se, and only when speciation analysis has been conducted will a detailed understanding of the system be possible. In the following, we carried out the speciation analysis of the creek waters in three of the main tributaries—Upper Fountain Creek, Monument Creek and Lower Fountain Creek—located in the Fountain Creek Watershed (Colorado, USA). There are statistically significant differences between the Se, Ca and Mg, levels in each of the tributaries and seasonal swings in Se, Ca and Mg levels have been observed. There are also statistically significant differences between the Se levels when grouped by Pierre Shale type. These factors are considered when determining the forms of Se present and analyzing their chemistry using the reported thermodynamic relationships considering Ca2+, Mg2+, SeO42−, SeO32− and carbonates. This analysis demonstrated that the correlation between Se and water hardness can be explained in terms of formation of soluble CaSeO4. The speciation analysis demonstrated that for the Fountain Creek waters, the Ca2+ ion may be mainly responsible for the observed correlation with the Se level. Considering that the Mg2+ level is also correlating linearly with the Se levels it is important to recognize that without Mg2+ the Ca2+ would be significantly reduced. The major role of Mg2+ is thus to raise the Ca2+ levels despite the equilibria with carbonate and other anions that would otherwise decrease Ca2+ levels.

Liquidity Risk, Bank Networks, and the Value of Joining the Federal Reserve System

Reducing systemic liquidity risk related to seasonal swings in loan demand was one reason for the founding of the Federal Reserve System. Existing evidence on the post-Federal Reserve increase in the seasonal volatility of aggregate lending and the decrease in seasonal interest rate swings suggests that it succeeded in that mission. Nevertheless, less than 8 percent of state-chartered banks joined the Federal Reserve in its first decade. Some have speculated that nonmembers could avoid higher costs of the Federal Reserve’s reserve requirements while still obtaining access indirectly to the Federal Reserve discount window through contacts with Federal Reserve members. We find that individual bank attributes related to the extent of banks’ ability to mitigate seasonal loan demand variation predict banks’ decisions to join the Federal Reserve. Consistent with the notion that banks could obtain indirect access to the discount window through interbank transfers, we find that a bank’s position within the interbank network (as a user or provider of liquidity) predicts the timing of its entry into the Federal Reserve System and the effect of Federal Reserve membership on its lending behavior. We also find that indirect access to the Federal Reserve was not as good as direct access. Federal Reserve member banks saw a greater increase in lending than nonmember banks.

Seasonal swings match latitudinal shifts in shut down

![Figure][1] Winter is generally not the best time of year for organisms. Temperatures are low and food is scarce, and for those species that can't fly south for the winter, surviving is a matter of hunkering down and making the best of a bad lot. But some individuals are lucky enough to

Prioritizing the Factors Affecting the Retailer’s Supply Chain Performance

In this study, we examined and prioritized the importance of a set of supply chain management (SCM) related factors on retailer’s performance. A two-level supply chain with linear demand and seasonal swings was simulated under varying operating situations in order to explore the relationships among bullwhip effect, lead time, forecast accuracy, seasonality, service levels and retailer’s performance. Next, a series of univariate tests were undertaken to identify the relationships among the simulation outputs including bullwhip ratio, total inventory cost, fraction of no stock-out cycles and fill rate. Finally, based on a structural equation model (SEM), a research framework was developed and tested in order to provide a rigorous analysis of the casual links among the SCM-related variables and retailer’s performance. Of the SCM-related factors, strong causal links were found between forecast inaccuracy and bullwhip ratio and also between lead time and total inventory cost. Desired service level was noted to...

Recensement des spores fongiques dans l’atmosphère de la ville de Sousse (Tunisie)

Introduction Outdoor atmospheric pollution seems to have a noticeable effect on the respiratory system, increasing of the prevalence of allergic respiratory diseases such as the asthma and the rhinitis. Purpose To determine fungal spore counts and their seasonal swings in the outdoor atmosphere of the city of Sousse, Tunisia during the year 2003. Materials and methods A volumetric Burkard © sensor was placed on the roof of the maternity service of the local hospital. Samples were sent every week to the European Bioclimatic Medical Center of Research and University Education (CEMBREU) for counting. The results were expressed as the number of fungal spores per cubic meter of air. The following meteorological data were recorded: relative humidity, mean annual outdoor temperature and mean annual rainfall. Results One hundred and sixty thousand and two hundred and ten fungal spores per cubic meter of air were detected in the outdoor atmosphere in Sousse. Four varieties of spores were observed: Alternaria, Cladosporium, Epicoccum and Botrytis. The maximum concentration of outdoor fungal spores was observed in spring. During this season, the density of Alternaria, Cladosporium and Epicoccum spores correlated in a positive and significant way with the temperature, which varied between 15°C and 25°C. Conclusion As a result of their high ambient concentrations, fungal spores could be considered to be an important etiological factor in allergic respiratory diseases including rhinitis and asthma.

Seasonal dynamics of dissolved Ra isotopes in the semi-arid bays of south Texas

Copano Bay, Nueces Bay, and Baffin Bay, Texas exhibit some of the highest dissolved 226Ra activities observed in coastal waters despite being in a semi-arid region where surface water is scarce. To determine the reason for this, dissolved 226Ra and 228Ra activities were measured in these bays at three periods during the course of their seasonal flushing cycles. CH 4 and dissolved Cl/Br ratios were also measured during the final sampling period to independently assess the possibility of oil-field brine leakage and its potential influence on bay Ra activities. Independent of the high bay Ra activities, evidence for oil-field brine leakage was not found, though we cannot discount this possible influence on the Ra budget. Our results do show that all three bays exhibit pronounced seasonal swings in Ra activity that culminate in high absolute values. Mixing model results indicated that supply from submarine groundwater discharge can balance the Ra budgets of these bays. However, the Ra cycle in these systems is not controlled by a single dominant process, but rather the seasonal relationship of riverine Ra supply, submarine groundwater discharge, input from benthic sediments, and direct evaporation. Thus these bays are best described by a Ra cycle where activities are controlled by several processes in a dynamic, seasonal equilibrium. This illustrates the importance of seasonal controls on estuarine Ra cycling in general, but seasonality may be especially important for semi-arid regions where the hydrologic cycle is influenced by episodic freshwater inputs.

Large seasonal swings in leaf area of Amazon rainforests

Despite early speculation to the contrary, all tropical forests studied to date display seasonal variations in the presence of new leaves, flowers, and fruits. Past studies were focused on the timing of phenological events and their cues but not on the accompanying changes in leaf area that regulate vegetation-atmosphere exchanges of energy, momentum, and mass. Here we report, from analysis of 5 years of recent satellite data, seasonal swings in green leaf area of approximately 25% in a majority of the Amazon rainforests. This seasonal cycle is timed to the seasonality of solar radiation in a manner that is suggestive of anticipatory and opportunistic patterns of net leaf flushing during the early to mid part of the light-rich dry season and net leaf abscission during the cloudy wet season. These seasonal swings in leaf area may be critical to initiation of the transition from dry to wet season, seasonal carbon balance between photosynthetic gains and respiratory losses, and litterfall nutrient cycling in moist tropical forests.

TROUT TAKE ON THERMAL CHALLENGE

Lake-dwelling fish are restricted to their watery homes, so they can't escape from seasonal temperature swings. Since fish are cold-blooded, they are sensitive to changes in temperature. So it's likely that their muscle performance – and therefore their swimming ability – is affected by hot and

Cold Capitalism: The Political Ecology of Frozen Concentrated Orange Juice

Abstract Frozen concentrated orange juice (FCOJ) was invented in 1945 by government researchers. To Florida orange growers beset by surplus production in some years and hard winter freezes in others, FCOJ was a "miracle" technology. Easily stored and transported, concentrate made it possible for orange juice processors to provide consumers with a uniform-quality product year-round. By the mid-1950s constantly rising consumer demand for FCOJ had essentially eliminated Florida orange growers’ constant surplus problem. Furthermore, many oranges that suffered from occasional winter frosts could be transformed into concentrate rather than destroyed. Thus, FCOJ appeared to rationalize the Florida orange industry in the 1950s, eliminating seasonal and annual swings in production and stabilizing prices and profits. However, when severe frosts attacked Florida groves in 1957-58 and again in 1962-63, FCOJ processors responded by doubling prices. Unlike other industrial agriculturists in American history, Florida orange growers and processors did not use technology to control nature in order to increase profits. Instead, they used the environmental limits imposed by Florida’s subtropical climate, along with their oligopolistic market position, to squeeze higher profits out of consumers. They respected the role of nature in limiting their production, not because they were enlightened ecologists, but because their control over orange juice production allowed them to make just as much money from a damaged crop of oranges as from a bumper crop. This case study thus calls into question the meaning of "rationalized" agriculture, showing that the logic of capitalist agriculture is not always straightforward.