Cold Temperate Climate Research Articles

Habitat, Niche, and Evolution of Sirenian Mating Systems

Lek polygyny, monogamy and scramble promiscuity have been reported in the two families and five species of Recent sirenians. Evidence for lek mating in the dugong or "sea pig" (Dugong dugon), monogamy in Steller's sea cow (Hydrodamalis gigas), and scramble promiscuity in the three manatees or "river cows" (Trichechus manatus, Trichechus senegalensis, and Trichechus inunguis), as well as in one dugong population, is reviewed. Sirenians are long-lived "K-strategists" with precocious young, few potential young per female lifetime, high female investment in a few young, little apparent opportunity for post-copulatory male investment, and "paenungulate" reproductive physiologies that appear to increase uncertainty as to female receptivity and assurance as to paternity. Common features notwithstanding, diverse habitats, climates, and niches may account for mating system diversity. Scenarios for evolution of diverse mating systems, based on our understanding of mating systems in terrestrial herbivores, are presented. The dugong retains the ancestral low latitude marine, seagrass dependent, bottom-feeding, niche characteristic of diverse, tusked, Oligocene and Miocene sirenian faunas. With a long breeding season and high polygyny potential, retention of tusks by male dugongs in the absence of any foraging function suggests that tusks may have always had social functions and lekking may be of ancient origin. The sea cow lineage, isolated on the shoreline of the northeastern Pacific as seagrasses declined, turned to surface foraging on chemically undefended kelps and lost both tusks and molar teeth. As it followed kelps northwards, adaptation to a cold-temperate climate compressed the breeding season, limited the polygyny potential, and, in conjunction with incentives for paternal investment, favored pair bonding and the monogamous mating system postulated by George Steller (1751). Manatees, evolving in botanically-rich fresh waters of the Amazon basin as an aberrant offshoot of the marine dugongid line, remained in the tropics and retained a high polygyny potential, but became generalist foragers in the upper few meters of the water column. Labyrinthine river systems provided little opportunity for male aggregation and display (or rhizome foraging) and tusks were lost as the uncertainty of female inseminability drove the mating system toward scramble promiscuity and sperm competition. An observation of manatee-like behavior in a dense and sedentary dugong population in eastern Australia suggests plasticity in sirenian mating, and the likelihood that a form of scramble promiscuity may exist where no suitable site for lekking is available, where large group size makes female defence impossible, or where vulnerability of territorial males to hunting has resulted in extirpation of a lekking tradition. Dugong and manatee life history characteristics conform to expectations based on observed differences in mating systems.

Effects of green manures on soil organic matter and wheat yields and N nutrition

A field study was conducted for 5 yr (1993-1997) to evaluate the effects of green manure residues applied to the soil in 1993 and 1995, on wheat (Triticum aestivum L.) yields and N nutrition as subsequent crop in 1994, 1996 and 1997. The effect of green manure application was also evaluated on soil microbial activity (CO2), on C and N contents of whole soil and on labile (LF) and heavy fractions (HF) of organic matter (OM). The experiment was initiated on a Le Bras silt loam (Humic Gleysol). The green manures, as a main factor, were clover (Trifolium pratense L.), buckwheat (Fagapyrum esculentum L.), millet (Echinicloa crus galli L.), mustard (Brassica hirta Moench), and colza (Brassica campestris L.), and there was a control without green manure. The sub-factors consisted of four N fertilizer rates for wheat in the subsequent years at 0, 30, 60 and 90 kg N ha–1. Broadcast application of 15N- labelled NH4NO3 was made in 90 kg N ha–1 fertilizer treatments. Two green manure applications did not influence the C and N contents of densimetric fractions of OM (LF and HF), but significantly increased those of whole soil, and microbial respiration (CO2). Green manures significantly increased wheat yields and N uptake in 1994 and 1996. Levels of N derived from fertilizer (Ndff) were lower in all green manure treatments as compared to the control, which indicates that the proportion of N derived from soil and green manures (% Ndfs) was higher in these treatments. The contribution of N from green manure varied in the following order: buckwheat < clover < mustard < millet < colza. With the exception of the clover treatment (< 100%), the N recoveries from the other green manure N (NRGM) ranged from 23 to 34% and from 19 to 36% for 1994 and 1996, respectively. Green manure application provided 15 to 24 kg N ha–1 in 1994 and from 16 to 36 kg N ha–1 in 1996 and this contribution accounted for 25 to 31% of the total wheat N uptake. Significant green manure effects on wheat yield and N nutrition were primarily due to the improvement of soil properties and to high N recoveries from the green manure. In the cold temperate climate of Québec, green manure incorporation into soil in late summer or early fall of the preceding year allowed N synchronization with wheat N needs in subsequent cropping seasons. Nitrogen fertilizer rates could be reduced after the incorporation of green manures having high yields and N contents in the previous season. Key words: Green manure, wheat yields and N uptake, N recoveries, microbial respiration, labile and heavy fractions of OM, C and N contents

A survey strategy and environmental monitoring network for an estuary supporting finfish cage culture

The Huon estuary, in southeastern Tasmania, is an important location for finfish, and to a lesser extent shellfish, farming. The Huon catchment is a lightly populated rural and forested region in a cold temperate climate which supports agriculture (horticulture and livestock), forestry, and tourism. The estuary (40 km in length) is microtidal, with a stratified to partially mixed water column. Effective design of sampling procedures for either monitoring or interdisciplinary studies is essential for resolution of the key time and space scales, and the operational programme must be relevant for events and processes in both the water column and the sediments. We chose to track seasonal changes in physical, chemical, and biological parameters by doing quarterly samplings of the water column at a grid of stations (63 in all) that encompassed the entire estuary from a freshwater end-member to a designated marine boundary. More rapid events were captured by monitoring (both autonomous instrument systems and manual sampling), at hourly to weekly intervals, at a small representative subset of the estuarine stations. Underway measurements from the research vessel were used to map transient surface and near-surface features. Sediments are long-term integrators of processes in the water column and therefore an intensive spatial survey of the sediment characteristics has been made to characterize the long-term influence of human activities. Knowledge gained from field observations of the baseline study has been used to outline an autonomous monitoring network that will derive the environmental information critical for the prudent management of the waterway for both its natural and commercial values.

The Late Permian climate. What can be inferred from climate modelling concerning Pangea scenarios and Hercynian range altitude?

A major unsolved geodynamic problem is the Permian Pangea plate configuration at the end of Paleozoic era (around 255 Ma). While consensual geology indicates a plate arrangement close to that of the Jurassic prior to the Atlantic opening (Pangea A), paleomagnetic data indicates a nearly 3000 km more eastward position of Gondwana with respect to Laurussia, leading to major plate and relieves reorganisation during Permo-Triassic times (Pangea B). Using an atmospheric general circulation model (AGCM), we simulate the climatic response to both configurations. We also test the fundamental role of paleo-elevations through sensitivity experiments. Each simulated climate is then compared with the aim of constraining the best fit to a particular paleogeographic scenario. Main trends of simulated Late Permian climate in agreement with paleoclimatic indicators are: (1) a warm temperate climate accompanied by a monsoon circulation over the eastern side of Gondwana; (2) a cold temperate climate marked by strong annual thermal amplitude at high latitudes in Gondwana and in Siberia; (3) an arid belt in the subtropics over the western side of Gondwana and Laurussia; and (4) strong climatic differences over both hemispheres, respectively. Main variance is found over Laurussia with a simulated tropical climate while an arid climate is suggested by paleodata. Simulating different paleo-elevations of the Appalachian and the Variscan fold belts can solve this discrepancy. The best model–data fit is reached for a mean altitude of 4500 m in the Appalachians and appears to be dependent of Pangea configuration with a southern Europe Variscan range of some 3000 m in a Pangea A configuration or only 2000 m in for Pangea B. Taking into account the geodynamic context, we argue that Pangea B appears to be the more probable configuration.

Abiogenic and Biochemogenic Alteration of Basaltic Glass under Low-Temperature Conditions

The material for investigations was obtained in Iceland in the area of active volcanism and tectonics in the recent rift zone under cold-temperate and humid climate and glacial conditions. The presence of abundant remnants of microbiota differently mineralized by palagonite was established in weathering zone on the surface of basaltic glass fragments situated at the top of hyaloclastites devoid of terrestrial vegetation. This gives conclusive evidence for the biochemogenic nature of palagonization in basaltic glass under these conditions. Among a number of possible reasons of the origination of palagonite, the most interesting is the relation of microbiological processes to the influx of gaseous hydrocarbons from the depth. This mechanism needs further investigations.

Metabolic adaptations of overwintering European common lizards (Lacerta vivipara).

The European common lizard Lacerta vivipara, a reptile of cold-temperate climates, provides us an interesting model of low-temperature adaptation. Indeed its unique cold-hardiness strategy, which employs both freeze tolerance and freeze avoidance, may be seen as the primary reason for its large distribution, which extends from Spain to beyond the Arctic circle. To study the metabolism supporting this capacity, we used three techniques: two techniques of calorimetry (oxygen consumption and thermogenesis) and nuclear magnetic resonance spectroscopy. These techniques were used to examine the metabolic balance and the different molecular pathways used between three different periods through the year (September, January, and May). The results show a significant 20% augmentation of winter anaerobic metabolism compared to other periods of the year. This is mainly because of an activation of the lactic fermentation pathway leading to an increase of lactate concentration (>34% in winter). Furthermore, glucose, which increases some 245% in winter, is used as antifreeze and metabolic substrate. Furthermore, this study provides evidence that the physiological adaptations of the common lizard differ from those of other ectotherms such as Rana sylvatica. Concentrations of alanine and glycerol, commonly used as antifreeze by many overwintering ectotherms, do not increase during winter.

Efficacy of the nematophagous fungus Duddingtonia flagrans in reducing equine cyathostome larvae on pasture in south Louisiana

The effectiveness of Duddingtonia flagrans in reducing the free living third stage larvae (L 3) of equine cyathostomes on pasture when fed to horses has been demonstrated in cold temperate climates. The objective of this experiment was to assess the efficacy of D. flagrans against equine cyathostomes in the subtropical environment of southern Louisiana. Fecal pats were prepared by mixing feces obtained from a parasite-free horse fed D. flagrans at a dose of approximately 2×10 6 spores kg −1, with feces containing cyathostome eggs from a parasitized horse. Control pats contained feces from a parasite-free horse mixed with feces containing cyathostome eggs. The fecal pats were placed on pasture in six replicates at 4-week intervals from March 1997 until January 1998. Comparison of recoveries of L 3 from non-treated control pats in the field with non-treated coprocultures maintained in the laboratory indicated that L 3 survival on pasture was reduced during the months of May, June, July, August and September. The efficacy of the fungus was determined by L 3 recovery from grass surrounding the fecal pats of treated and control groups. D. flagrans significantly reduced L 3 during the months of April, May, and October 1997 to January 1998 (range 66–99% reduction, p=0.0001), and for the year as a whole ( p=0.0001).

Winter fluxes of greenhouse gases from snow‐covered agricultural soil:intra‐annual and interannual variations

Despite the length of winter in cold temperate climates, few studies refer to greenhouse gas emissions from soils during the nongrowing season. In this study, N2O and CO2 fluxes from agricultural and forest soils in southeastern Quebec (Canada) were measured during winter and spring from 1994 to 1997, and the influences of climate, soil, and snow properties on the gaseous emissions were examined. N2O fluxes were far greater from the agricultural soil (2‐187 ng N2O m−2 s−1) than from the forest soil (< 3 ng N2O m−2 s−1), but CO2 fluxes were equivalent for both soil systems (2‐102 μ CO2 m−2 s−1). The higher N2O concentrations in the lower soil horizons could be explained by positive temperature gradients with depth and concomitant negative gas solubility gradients. However, the higher N2O concentrations could also be explained by variations in the expression of N2O reductase with depth, which can modify the N2/N2O ratios in relation to the availability of O2. Calculated N2O‐N fluxes showed that N losses by gaseous emissions from soils during winter and spring were comparable to, or exceeded, similar reported N losses during the growing season. The highest winter fluxes observed in 1997 were interpreted to be due to favorable meteorological conditions that prevailed for denitrification through high soil water content in summer and fall of 1996. Although interannual and nterseasonal variations of fluxes are important, this study shows that wintertime losses of N2O from agricultural soil can be up to 2 to 4 times greater than emissions measured during the growing season in similar agroecosystems.

Window pane condensation and high indoor vapour contribution - markers of an unhealthy indoor climate?

The aim of this study was to investigate whether window pane condensation and indoor vapour contribution >/= 3 g/m3 could be used as indicators of defective air change rate, high indoor humidity and high mite allergen concentration in mattress dust. Actual ventilation rate, indoor temperature, air humidity (AIH/RH) and concentrations of mite allergen were measured in 59 houses and compared with received outdoor temperatures and air humidity. Indoor vapour contribution defined as the difference between the indoor and the outdoor vapour concentration was calculated. Sensitivity, specificity, predictive values and accuracy were calculated for window pane condensation and high vapour contribution (>/= 3 g/m3), as indicators of defective ventilation (< 0.5 ACH), high indoor humidity (>/= 7 g/kg and >/= 45% RH) and high mite allergen concentration in mattress dust (>/= 2 microg/g). All houses with high humidity and high mite allergen concentrations were positive for the two indicators (high sensitivity), but with a specificity of only 50% so that half of the houses with reported condensation and high vapour contribution turned out to be low pollution houses with adequate high ventilation levels. Both indicators had high negative predictive values and absence of the two indicators almost certainly (97-100%) excluded high indoor pollution with high humidity and high mite concentrations. Overall more than 70% of the dwellings were correctly classified by the two indicators. Absence of window pane condensation on double-glazed windows and low indoor vapour contribution (< 3 g/m3) during the winter are true markers of a dwelling without high indoor air humidity and without high mite allergen concentrations in mattress dust in houses in a cold temperate climate with subzero outdoor temperatures. The presence of the two indicators is associated with a 18-45% risk of high humidity and mite allergen concentrations so in this latter group further measurements are needed for correct classification.

Seasonal response of denitrifiers to temperature in a Quebec cropped soil

While some studies indicate no denitrification activity in early spring, others have demonstrated that denitrifiers from temperate region soils can adapt to low temperatures. The aim of the present paper was to study how seasonal changes in temperature affect denitrifying enzyme activity (DEA) in a cropped humic gleysol located in a cold temperate climate (Quebec). Soil was sampled monthly during a 16-mo period and DEA was measured at nine temperatures from 2 to 35°C. A seasonal effect of temperature on DEA was significant at all incubation temperatures and was more important in November and in May–June. The effect of temperature on DEA was better fitted with the square root model of Ratkowsky than with the Arrhenius equation. The regression coefficient b (Ratkowsky parameter) varied seasonally with a trend similar to that of DEA. These results show that the Ratkowsky model should be used instead of Arrhenius equation to describe the effect of cold temperature on denitrification. Key words: Denitrification, temperature, cold, Arrhenius equation, Ratkowsky model

How ‘Green’ Are Aquaculture, Constructed Wetlands and Conventional Wastewater Treatment Systems?

The term ‘green’ is nowadays widely used (and misused) in connection with many types of technologies. If a technology is ‘green’ it usually means that the technology requires less non-renewable energy sources than other alternatives. However, other parameters need to be considered as well, such as sustainability, recycling potential, treatment capacity and potential, conservation of ecosystems, etc. In this paper the energy requirements and nutrient recycling potential of constructed wetlands and wastewater aquaculture facilities are compared with that of conventional wastewater treatment technologies. The energy requirements of constructed wetlands are very low, but if significant reuse of nutrients is included (aquaculture), the energy requirements increase significantly and usually beyond the energy equivalent of the biomass produced. This is especially true in cold temperate climates where the aquaculture systems need to be housed in heated greenhouses and artificial light must be provided to secure operation throughout the year. In countries where fresh water itself is a limiting resource and where the economic capability may limit the use of artificial fertilisers, the reuse potential of wastewater may be more important. The potential for sustainable cropping of the plant biomass is excellent in tropical wetlands as the plants have a high productivity and a continuous growing season. In order to evaluate in more detail the ‘greenness’ of the different wastewater treatment technologies, the life-cycle approach might be applied. However, because constructed wetlands, besides the water quality improvement function, perform a multitude of other functions such as biodiversity, habitat, climatic, hydrological and public use functions, methodologies need to be developed to evaluate these functions and to weigh them in relation to the water quality issues.

Upper Palaeozoic carbonate reservoirs on the Norwegian arctic shelf; delineation of reservoir models with application to the Loppa High

The reservoir potential of the Upper Palaeozoic carbonates in the Barents Sea area is primarily controlled by early diagenetic processes. Upper Bashkirian to Asselian shallow platform carbonates deposited in warm, arid to semi-arid climates were dominated by aragonitic organisms and mineralogically unstable aragonite and high-Mg calcite cements and mud. A reservoir model for these carbonates involves extensive dolomitization and dissolution of metastable carbonate during repeated subaerial exposure. The reservoir model is confirmed by drilling and is accordingly regarded as low risk. Artinskian and Upper Permian shallow water carbonates deposited in a cold temperate climate were dominated by calcitic organisms and silica sponges, and associated with calcite cements and mud and chert. A reservoir model for these carbonates involves either preservation of primary porosity in carbonate build-ups or extensive dissolution of build-up marine cement during prolonged subaerial exposure. This model is not confirmed by drilling and is regarded as high risk.

How ‘green’ are aquaculture, constructed wetlands and conventional wastewater treatment systems?

The term ‘green’ is nowadays widely used (and misused) in connection with many types of technologies. If a technology is ‘green’ it usually means that the technology requires less non-renewable energy sources than other alternatives. However, other parameters need to be considered as well, such as sustainability, recycling potential, treatment capacity and potential, conservation of ecosystems, etc. In this paper the energy requirements and nutrient recycling potential of constructed wetlands and wastewater aquaculture facilities are compared with that of conventional wastewater treatment technologies. The energy requirements of constructed wetlands are very low, but if significant reuse of nutrients is included (aquaculture), the energy requirements increase significantly and usually beyond the energy equivalent of the biomass produced. This is especially true in cold temperate climates where the aquaculture systems need to be housed in heated greenhouses and artificial light must be provided to secure operation throughout the year. In countries where fresh water itself is a limiting resource and where the economic capability may limit the use of artificial fertilisers, the reuse potential of wastewater may be more important. The potential for sustainable cropping of the plant biomass is excellent in tropical wetlands as the plants have a high productivity and a continuous growing season. In order to evaluate in more detail the ‘greenness’ of the different wastewater treatment technologies, the life-cycle approach might be applied. However, because constructed wetlands, besides the water quality improvement function, perform a multitude of other functions such as biodiversity, habitat, climatic, hydrological and public use functions, methodologies need to be developed to evaluate these functions and to weigh them in relation to the water quality issues.

Nothofagidites Erdtman ex Potoniédans le Paléogène de l'île Roi Georges, Antarctique

Nothofagidites (fusca and brassii) were found in the Palaeogene of King George Island (SouthShetland Islands). They are associated with a rich palynoflora composed of many ferns, Podocarpaceae, Araucariaceae, Proteaceae and Gunneraceae. A comparative study of extant and fossil pollen grains (optical microscope and SEM) allowed the establishment of some botanical affinities with South American species to be established. Nevertheless the Nothofagidites of King George Island have an exine with strong spines, a characteristic of some species of the brassii group living in New Guinea and New Caledonia under a warm and humid climate. According to these data, and those based on the study of fossil woods from the same sites, it appears that, during Palaeogene, the fossil southern beech (Nothofagus) were trees of warm and humide climate with alternation of dry and wet seasons. These trees were growing together with plants now living under a subtropical climate. During glacial periods and through the volcanic and tectonic events of the late Paleogene, at least some Nothofagus species migrated, became adapted to the climatic changes and live today in the Southern Hemisphere cold temperate forests, particularly in southern Chile. So the sole presence of Nothofagus in the Tertiary sediments cannot be used as a criterion for the existence of a cold temperate climate as it is often argued.

Seasonal Variation in Cold Tolerance, Basal Metabolic Rate, and Maximal Capacity for Thermogenesis in White-Breasted Nuthatches Sitta carolinensis and Downy Woodpeckers Picoides pubescens, Two Unrelated Arboreal Temperate Residents

White-breasted Nuthatches Sitta carolinensis and Downy Woodpeckers Picoides pubescens are permanent residents in areas with cold temperate climates and are ecologically similar, but belong to different taxonomic orders. We measured basal metabolic rate (BMR) and peak metabolic rate (PMR = peak rate of cold-induced thermogenesis) for wild, free-living summer and winter acclimatised White-breasted Nuthatches and Downy Woodpeckers to determine seasonal and interspecific variation in cold tolerance and thermogenic ability. Both species were more cold tolerant and had significantly higher BMR and PMR in winter than in summer. Furthermore, during midsummer (early July to mid-August), nuthatches exhibited a significant decrement in cold tolerance and PMR relative to other seasons. A winter increment of metabolism, coupled with only minor seasonal variation in body mass and fat scores in both species, indicates that both species rely more on metabolic adjustments than gross morphological adjustments for winter acclimatisation. Woodpeckers and nuthatches exhibited roughly similar BMR and PMR at both seasons. The only significant interspecific differences in metabolic rates involved per-bird PMR in winter and midsummer, per-bird BMR in winter and summer (woodpeckers > nuthatches in both cases), and mass-specific PMR in summer (early/ late summer nuthatches > summer woodpeckers). Interspecific differences in cold tolerance and metabolic rates are probably explained, at least in part, by differences in body mass, as woodpeckers were significantly larger than nuthatches at all seasons. These data indicate that White-breasted Nuthatches and Downy Woodpeckers exhibit similar thermogenic performance and major phylogenetic effects on thermoregulation are not apparent.

The palaeoclimate of the Karoo: evidence from plant fossils

Abstract The common and conspicuous Karoo fossil floras flourished in what appears to be climatically disadvantageous conditions, as southern Gondwana lay within the Antarctic Circle throughout much of the Permian. Most previous climatic reconstructions suggest a cold-temperate climate. Plant structures are sensitive to environmental conditions, particularly climate, and may be used to predict these conditions. Large Glossopteris leaves dominate fossil plant assemblages, and considerable deposits of coal were laid down at this time. Quantitative analyses of fossil leaves from three coeval localities indicate that the climate prevailing at the time of the burial of these Glossopteris floras was seasonal, with summer conditions extremely favourable for plant growth, comparable to tropical regions today, and winters that were also correspondingly warmer than has previously been suggested.

Solar heat transformation alternatives

SYNOPSIS The utilization of solar energy in wintertime corresponds with the low temperature of the produced heat, which is often too low to directly feed heating plants. Heat transformation appears to be an attractive way of increasing the temperature of solar fluids, so that in the present paper some solutions are examined with different operating mixtures, i.e. H2O-LiBr, CH3OH-LiBr, CH3OH-LiBr-ZnBr2 (2:1, 3:1). The overall efficiencies of the mentioned systems are determined, as well as the heat rates and the exergetic efficiencies. The conclusions are positive, especially with low values of the solar radiant power Wi. For values of Wi less than 700W/m2, which cover the majority of situations in temperate climates, it is remarkable that the introduction of an absorption heat transformer increases the overall efficiency; the advantage becomes very appropriate for low values of Wi, as it is usual in cold-temperate climates.

Reduced mite allergen levels in dwellings with mechanical exhaust and supply ventilation

Seventy similar bungalows constructed between 1968 and 1970 in the same suburban area of Stockholm were investigated regarding the content of house dust mite allergen, absolute indoor humidity, type of ventilation and basement construction. Houses with mechanical exhaust and supply ventilation had an indoor humidity above 7 g/kg less often than houses without this type of ventilation (Odds ratio 0.1, 95% confidence interval 0.0-0.2). Furthermore, only five of the 24 houses with exhaust and supply ventilation contained mattress dust mite allergen concentrations exceeding the median value (98.5 ng/g) compared with 30 of 46 hours which did not have such ventilation (odds ratio = 0.1, C.I. 0.0-0.5). Houses with both natural ventilation and crawl space basement harboured significantly less mattress mite allergen than houses having the same type of ventilation, but with a concrete slab basement. In a cold temperature climate, type of building construction and ventilation seem to be important for the occurrence of house dust mite allergens in dwellings. Our results indicate that modern energy-efficient houses should be equipped with mechanical exhaust and supply ventilation to reduce indoor air humidity during the dry winter months and the risk of mite infestation.

Structurally preserved larch and spruce cones from the Pliocene of Alaska

Twenty-three specimens of seed cones from early Pliocene terrace gravels outcropping between Birch Creek and the town of Circle in east-central Alaska were studied. The cones are preserved as semifusain and internal tissue structure is present, permitting close comparison of anatomical details of the fossil with those of modern counterparts. Six specimens represent Larix circlensis, a new species of larch that is most similar to cones of the modern L. decidua, which occurs today through the Alps and Carpathians of southern Europe. Seventeen cones belong to Picea and are indistinguishable from those of P. glauca (white spruce), which grows in interior Alaska today. White spruce and many species of modern larch grow under cool to cold temperate climates. Both conifers are capable of becoming established on immature and exposed soils and are often dominant taxa in modern boreal forests. These general conditions of climate and ecology are inferred for the early Pliocene of interior Alaska.

Experimental intensive culture of Penaeus monodon in the cold-temperate climate of the North-East coast of Italy (a fishery ‘valle’ of the River Po Delta)

An intensive culture trial was conducted with the black tiger shrimp, Penaeus monodon Fabricius, on the North-East coast of Italy, characterized by a cold temperate climate. The culture was carried out in two steps: a pre-growing phase in fibreglass tanks lasting 31 days, and a 71-day grow-out phase (stocking density of 9.1 individuals m −2) in an earthen pond (0.79 ha). Survival rate was 55.4% during the first phase and 73.8% during the second phase, with an overall 40.9% recovery rate at the end of the trial. Average final weight was 17.9 g with a monthly wet weight increase of 7.49 g during the grow-out phase; production in the pond reached 1208 kg·ha −1 in 71 days. Temperature appeared to be the main environmental factor influencing the intensive culture process.