Positive Effect Of Temperature Research Articles

Direct and indirect effects of elevation, climate and vegetation structure on bird communities on a tropical mountain

Climate and vegetation structure are important predictors of biodiversity along mountain slopes. The drivers of elevational biodiversity gradients are not yet fully resolved. For instance, there is little understanding of how direct and indirect effects of elevation shape species communities along mountain slopes. In this study, we identify the main drivers of bird diversity along an elevational gradient spanning 2000 m in the Ecuadorian Andes. We simultaneously tested the direct and indirect effects of elevation, temperature, precipitation and vegetation structure on overall bird diversity and on frugivorous and insectivorous birds, using structural equation models (SEMs). We found that elevation was mostly indirectly associated with bird diversity, mediated via abiotic (i.e., temperature, precipitation) and biotic (i.e., vegetation structure) factors. We found consistent positive effects of temperature and vegetation structure and negative effects of precipitation on overall bird diversity and on frugivorous and insectivorous birds. In addition, elevation was directly, positively associated with insectivore richness and abundance, but not with that of frugivores. Our results show that climatic factors and vegetation structure jointly shape the richness of bird communities on tropical mountains. However, other factors, such as biotic interactions or different evolutionary histories of lowland and highland communities, may additionally contribute to elevational patterns in bird diversity. Thus, species communities across tropical mountain slopes are shaped by a multitude of abiotic and biotic factors that need to be studied simultaneously for a mechanistic understanding of patterns in biodiversity.

Can Variations in Temperature Explain the Systemic Risk of European Firms?

We employ a varDelta CoVaR model in order to measure the potential impact of temperature fluctuations on systemic risk, considering all companies from the STOXX Europe 600 Index, which covers a wide range of industries for the period from 1/1/1990 to 29/12/2017. Furthermore, in this study, we decompose temperature into 3 factors; namely (1) trend, (2) seasonality and (3) anomaly. Findings suggest that, temperature has indeed a significant impact on systemic risk. In fact, we provide significant evidence of either positive or nonlinear temperature effects on financial markets, while the nonlinear relationship between temperature and systemic risk follows an inverted U-shaped curve. In addition, hot temperature shocks strongly increase systemic risk, while we do witness the opposite for cold shocks. Additional analysis shows that deviations of temperature by 1,^{circ }hbox {C} can increase the daily Value at Risk by up to 0.24 basis points. Overall, higher temperatures are highly detrimental for the financial system. Results remain robust under the different proxies that were employed to capture systemic risk or temperature.

Response of juveniles of seven forest tree species and their populations to different combinations of simulated climate change-related stressors: spring-frost, heat, drought, increased UV radiation and ozone concentration under elevated CO2 level.

The study aimed to assess response of juvenile progeny of seven forest tree species, Pinus sylvestris, Picea abies, Betula pendula, Alnus glutinosa, Populus tremula, Quercus robur and Fraxinus excelsior, and their populations to different combinations of climate change-related multiple stressors, simulated in a phytotron under elevated CO2 concentration: (1) heat + elevated humidity (HW); (2) heat + frost + drought (HFD); (3) heat + elevated humidity + increased UV-B radiation doses + elevated ozone concentration (HWUO); and (4) heat + frost + drought + increased UV-B radiation doses + elevated ozone concentration (HFDUO). Effects of the complex treatments, species and species-by-treatment interaction were highly significant in most of the growth, physiological and biochemical traits studied, indicating general and species-specific responses to the applied treatments. For deciduous trees, height increment was much higher under HW treatment than in ambient conditions (control) indicating a positive effect of elevated temperature and better water and CO2 availability. HFD treatment caused reduction of height increment in comparison to HW treatment in most species except for Q. robur and F. excelsior which benefited from lower humidity. Treatments HWUO and HFDUO have caused substantial damages to leaves in fast growing deciduous P. tremula, A. glutinosa and B. pendula, and resulted in their lower height increment than in HW treatment, although it was the same or even higher than that in the control. Rates of photosynthesis in most of the tree species were greatest in HFD treatment. A lower photosynthetic rate (compared to control) was observed in B. pendula, P. tremula and F. excelsior in HW treatment, and in most species-in HWUO treatment. Compared to control, intrinsic water use efficiency in all treatments was significantly lower in P. tremula, A. glutinosa and F. excelsior and higher in conifers P. sylvestris and P. abies. Significant population-by-treatment interactions found for most traits showed variation in response of populations, implying that this reflects adaptive potential of each tree species. The observed responses may not always be considered as adaptive as deteriorating growth of some populations or species may lead to loss of their competitiveness thus compromising regeneration and natural successions.

Liberation and Micellarization of Carotenoids from Different Smoothies after Thermal and Ultrasound Treatments.

The consumption of a varied diet rich in fruit and vegetables helps prevent and treat certain chronic diseases. The development of smoothies based on derivatives from fruit and vegetables rich in bioactive compounds can help increase the consumption of these foods, and therefore, contribute to the prevention of various health problems. However, during the processing of the fruit and vegetable smoothies, these properties may change. The elaboration of smoothies is based on fruits and vegetables rich in carotenoids: Carrot juice-papaya-mango (smoothie A) and carrot juice-pumpkin-mango (smoothie B). The objective of this study is to evaluate the impact of the application of different thermal technologies (mild and intensive heat treatment) and non-conventional technologies (ultrasound) on carotenoids (α-carotene, β-carotene, lutein and β-cryptoxantin) and determine the physiochemical parameters of derivatives from fruit and vegetable smoothies. In addition, the bioaccessibility of carotenoids is also evaluated through a process of in vitro simulated digestion. With regard to the bioaccessibility of the fruit and vegetable smoothies analyzed, a positive effect of temperature on liberation and micellarization was observed.

Direct and indirect effects of regional and local climatic factors on trophic interactions in the Arctic tundra

Climate change can impact ecosystems by reshaping the dynamics of resource exploitation for predators and their prey. Alterations of these pathways could be especially intense in ecosystems characterized by a simple trophic structure and rapid warming trends, such as in the Arctic. However, quantifying the multiple direct and indirect pathways through which climate change is likely to alter trophic interactions and their relative strength remains a challenge. Here, we aim to identify direct and indirect causal mechanisms driven by climate affecting predator-prey interactions of species sharing a tundra food web. We based our study on relationships between one Arctic predator (Arctic fox) and its two main prey - lemmings (preferred prey) and snow geese (alternate prey) - which are exposed to variable local and regional climatic factors across years. We used a combination of models mapping multiple causal links among key variables derived from a long-term dataset (21years). We obtained several possible scenarios linking regional climate factors (Arctic oscillations) and local temperature and precipitation to the breeding of species. Our results suggest that both regional and local climate factors have direct and indirect impacts on the breeding of foxes and geese. Local climate showed a positive causal link with goose nesting success, while both regional and local climate displayed contrasted effects on the proportion of fox breeding. We found no impact of climate on lemming abundance. We observed positive relationships between lemming, fox and goose reproduction highlighting numerical and functional responses of fox to the variability of lemming abundance. Our study measures causal links and strength of interactions in a food web, quantifying both numerical response of a predator and apparent interactions between its two main prey. These results improve our understanding of the complex effects of climate on predator-prey interactions and our capacity to anticipate food web response to ongoing climate change.

Long‐term survey data reveal large predator and temperature effects on population growth of multiple zooplankton species

AbstractPredators can strongly affect prey communities, but their influence may be difficult to distinguish from bottom‐up and other environmental effects. The problem of assessing predator impact is especially difficult in large systems that do not allow for comparisons across multiple units (e.g., small lakes) that have varying predator density. For instance, the invasion of the predatory zooplankter, Bythotrephes longimanus, into the Laurentian Great Lakes contributed to the nearly complete disappearance of several zooplankton species, but current effects on extant zooplankton are not well understood. We used generalized additive models (GAMs) applied to long‐term data time series (1994–2012) to examine B. longimanus effects on zooplankton species in Lake Michigan. Because B. longimanus abundance varied over time, our approach allowed assessment of predator effects from field data while accounting for other factors, including food resources, temperature, and seasonality. Results suggest that B. longimanus substantially reduces some zooplankton population growth rates, with the largest effects on species that B. longimanus affected more strongly in experiments. For example, at maximum B. longimanus abundance, Daphnia mendotae, Bosmina longirostris, and Diacyclops thomasi population growth rates were estimated to be reduced by 17%, 30%, and 21%, respectively, compared to no effect on calanoid copepods. Results further indicated positive temperature effects on population growth that differed by species. Our study thus provides field‐based evidence for ongoing impacts of invasive species and temperature on zooplankton production and composition, with potential consequences for planktivorous fish, and exemplifies how GAMs can be used to determine predator effects from time series data.

Determinants of Urban Residential Water Demand in Libya

This article analyzes the effect of several economic, environmental and social determinants for the per capita demand for water in Libya. Besides prices, income and population size, the article reflects the impact of urban population size, the temperature, summer temperature, and precipitation. The article also explores why the current per capita residential water demand in the urban areas is about more than in the other areas in Libya. In this study, the econometric model based on E-views method, instrumental-variable procedures, the ARDL model and the demand equation are applied. The co-integration analysis has shown a significant positive effect of temperature on water demand over the short and long term with partial flexibility of long-term temperature (5.44). Also, there is a positive relationship between rainfall and water demand in the long term and its less impact in the short term. There is a significant positive relationship between urban population and water demand. The greater urban population is greater the water demand and vice versa, partial flexibility of the urban population in the long term is at 0.23. On the other hand, there is a significant negative effect of income on water demand. Therefore, water demand is inflexible to changes in income. The study demonstrated that there is a negative effect on water price in relation to water demand. The estimated long-term variable of water value is 220.98, indicates that if the water price increases by 100%, the demand for water will go down by 221%.

Vegetation dynamics and their relationships with climatic factors in the Qinling Mountains of China

The “China Core” of China’s ecosystem, the Qinling Mountains (QM), occupies a special geographical location and has a unique ecosystem. Recently, the growth of vegetation has become an important indicator, reflecting the changes of the ecosystem. The characteristics of spatio-temporal variation of the vegetation and their relationships with climatic factors in the QM were analyzed using the Normalized Difference Vegetation Index (NDVI), based on statistical analysis and Hurst exponent analysis. The results showed that NDVI generally increased over the past 16 years, with increasing NDVI occupying 96.29% of the total study area. The marginal areas of the northern QM were the major regions showing decreasing vegetation growth, while the largest increase in vegetation growth occurred in the northwest. Changes in topographical elements (slope, elevation) had marked impact on vegetation growth, with degraded vegetation being mainly distributed on slopes <30° and at an elevation <1000 m. In the growing season, the relationship between increased precipitation and increased NDVI became weak when average precipitation exceeded 80 mm, whereas the positive effects of average temperature on NDVI increased as the temperature rose. The change-point of NDVI mainly occurred in the southwestern margin and the central-eastern regions of the QM, especially in 2006, 2007 and 2008. This study provides useful information on the vegetation growth status in the QM, and has practical implications for government policy in the vegetated areas.

Contrasting consequences of climate change for migratory geese: Predation, density dependence and carryover effects offset benefits of high-arctic warming.

Climate change is most rapid in the Arctic, posing both benefits and challenges for migratory herbivores. However, population-dynamic responses to climate change are generally difficult to predict, due to concurrent changes in other trophic levels. Migratory species are also exposed to contrasting climate trends and density regimes over the annual cycle. Thus, determining how climate change impacts their population dynamics requires an understanding of how weather directly or indirectly (through trophic interactions and carryover effects) affects reproduction and survival across migratory stages, while accounting for density dependence. Here, we analyse the overall implications of climate change for a local non-hunted population of high-arctic Svalbard barnacle geese, Branta leucopsis, using 28years of individual-based data. By identifying the main drivers of reproductive stages (egg production, hatching and fledging) and age-specific survival rates, we quantify their impact on population growth. Recent climate change in Svalbard enhanced egg production and hatching success through positive effects of advanced spring onset (snow melt) and warmer summers (i.e. earlier vegetation green-up) respectively. Contrastingly, there was a strong temporal decline in fledging probability due to increased local abundance of the Arctic fox, the main predator. While weather during the non-breeding season influenced geese through a positive effect of temperature (UK wintering grounds) on adult survival and a positive carryover effect of rainfall (spring stopover site in Norway) on egg production, these covariates showed no temporal trends. However, density-dependent effects occurred throughout the annual cycle, and the steadily increasing total flyway population size caused negative trends in overwinter survival and carryover effects on egg production. The combination of density-dependent processes and direct and indirect climate change effects across life history stages appeared to stabilize local population size. Our study emphasizes the need for holistic approaches when studying population-dynamic responses to global change in migratory species.

The effect of low positive temperature on the content of low molecular weight antioxidants in the organs of a vegetable chrysanthemum plant

The use of the rapid amperometric method made it possible to promptly measure and evaluate the total content of water- and ethanol-soluble antioxidants in extracts from Chryzantemum coronarium L. plants. The effect of optimal and low positive temperatures on the accumulation of low molecular weight antioxidants: ascorbic acid, phenolic compounds, soluble carbohydrates, carotenoids in various organs of vegetable chrysanthemum plant were investigated. In the leaves of the studied varieties, the content of flavonoids was two times higher than in the stems, while the accumulation level of condensed and polymeric polyphenols in the stem was three times higher than the level of their accumulation in the leaves. The maximum total antioxidant content was found in the inflorescences, whereas in other organs of the plant they accumulated 2-3 times less. Under the conditions of hypothermia in November, the amount of ascorbic acid, photosynthetic pigments and the total antioxidant content remained at a higher level in the upper photosynthesizing leaves. The data obtained indicate the important role of low molecular weight antioxidants in the protection of plant cells under the action of low positive temperatures.

Weather and daily mobility in international perspective: A cross-comparison of Dutch, Norwegian and Swedish city regions

With climate change, weather has emerged as an important theme in transport research and planning. Although recent studies demonstrate profound weather effects on mobility in single case study areas, international cross-comparisons are required to reveal how effects differ between cities with different transport and climate regimes. This paper provides an international cross-comparison of the simultaneous effects of weather on destination choices, distances, trip chaining, and transport modes in the urban regions of Utrecht (Netherlands), Oslo and Stavanger (Norway), and Stockholm (Sweden). Hereto, regional subsamples of national travel survey data were linked to meteorological records for the three respective countries and analysed in generalised Structural Equation Models. Our findings generally indicate that light, calm, dry and warm atmospheric conditions may positively affect cycling and the selection of outdoor leisure destinations, while cold and to a lesser extent wet and windy weather conditions reduce cycling and enhance car use and travel optimising strategies like trip chaining, to reduce weather exposures. A positive effect of air temperature on cycling flattens out above 20–25 °C in most of our study areas, but hot weather does not seem to reduce cycling strongly. However, our findings also show considerable regional differences in the effects of weather on mobility. Both general effects and differences are interpreted in relation to geographical context, transport and land use, climate conditions, cultures, habits and adaptations and are discussed to formulate policies to mitigate active transport mode users’ exposures to adverse weather and make walking and cycling (even more) year-round modes.

Exploring thermal flight responses as predictors of flight ability and geographic range size in Drosophila

Thermal flight performance curves (TFPCs) may be a useful proxy for determining dispersal on daily timescales in winged insect species. Few studies have assessed TFPCs across a range of species under standard conditions despite that they may be useful in predicting variation in performance, abundance or geographic range shifts with forecast climate variability. Indeed, the factors determining realized dispersal within and among flying insect species are generally poorly understood. To better understand how flight performance may be correlated with geographic range extent and potential latitudinal climate variability, we estimated the thermal performance curves of flight ability in 11 Drosophilidae species (in 4 °C increments across 16–28 °C) after standard laboratory rearing for two generations. We tested if key morphological, evolutionary or ecological factors (e.g. species identity, sex, body mass, wing loading, geographic range size) predicted traits of TFPCs (including optimum temperature, maximum performance, thermal breadth of performance) or flight ability (success/failure to fly). Although several parameters of TFPCs varied among species these were typically not statistically significant probably owing to the relatively small pool of species assessed and the limited trait variation detected. The best explanatory model of these flight responses across species included significant positive effects of test temperature and wing area. However, the rank of geographic distribution breadth and phylogeny failed to explain significant variation in most of the traits, except for thermal performance breadth, of thermal flight performance curves among these 11 species. Future studies that employ a wider range of Drosophilidae species, especially if coupled with fine-scale estimates of species' environmental niches, would be useful.

Winter Wheat Green-up Date Variation and its Diverse Response on the Hydrothermal Conditions over the North China Plain, Using MODIS Time-Series Data

Vegetation phenology plays a critical role in the dynamic response of terrestrial ecosystems to climate change. However, the relationship between the phenology of winter wheat and hydrothermal factors is inadequate, especially in typical agricultural areas. In this study, the possible effects of preseason climate changes on the green-up date (GUD) of winter wheat over the North China Plain (NCP) was investigated, using the MODIS EVI 8-day time-series data from 2000 to 2015, as well as the concurrent monthly mean temperature (Tm), mean maximum (Tmax) and minimum temperature (Tmin) and total precipitation (TP) data. Firstly, we quantitatively identified the time lag effects of winter wheat GUD responses to different climatic factors; then, the major driving factors for winter wheat GUD were further explored by applying multiple linear regression models. The results showed that the time lag effects of winter wheat GUD response to climatic factors were site- and climatic parameters-dependent. Negative temperature effects with about a 3-month time lag dominated in most of the NCP, whereas positive temperature effects with a zero-month lag were most common in some of the southern parts. In comparison, total precipitation had a negative zero-month lag effect in the northern region, but two lagged months occurred in the south. Regarding the time lag effects, the explanation power of climatic factors improved relatively by up to 77%, and the explanation area increased by 41.20%. Additionally, change in winter wheat GUD was primarily determined by temperature rather than by TP, with a marked spatial heterogeneity of the Tmax and Tmin effect. Our results confirmed different time lag effects from different climatic factors on phenological processes in spring, and further suggested that both Tmax and Tmin should be considered to improve the performance of spring phenology models.

Detection of environmental and morphological adaptation despite high landscape genetic connectivity in a pest grasshopper (Phaulacridium vittatum).

Widespread species that exhibit both high gene flow and the capacity to occupy heterogeneous environments make excellent models for examining local selection processes along environmental gradients. Here we evaluate the influence of temperature and landscape variables on genetic connectivity and signatures of local adaptation in Phaulacridium vittatum, a widespread agricultural pest grasshopper, endemic to Australia. With sampling across a 900-km latitudinal gradient, we genotyped 185 P.vittatum from 19 sites at 11,408 single nucleotide polymorphisms (SNPs) using ddRAD sequencing. Despite high gene flow across sites (pairwise FST =0.0003-0.08), landscape genetic resistance modelling identified a positive nonlinear effect of mean annual temperature on genetic connectivity. Urban areas and water bodies had a greater influence on genetic distance among sites than pasture, agricultural areas and forest. Together, FST outlier tests and environmental association analysis (EAA) detected 242 unique SNPs under putative selection, with the highest numbers associated with latitude, mean annual temperature and body size. A combination of landscape genetic connectivity analysis together with EAA identified mean annual temperature as a key driver of both neutral gene flow and environmental selection processes. Gene annotation of putatively adaptive SNPs matched with gene functions for olfaction, metabolic detoxification and ultraviolet light shielding. Our results imply that this widespread agricultural pest has the potential to spread and adapt under shifting temperature regimes and land cover change.

Growth of Penaeus aztecus Ives, 1891 and Penaeus duorarum Burkenroad, 1931 in a hypersaline lagoon: relationships with environmental conditions and body size

Growth rates of the brown shrimp Penaeus aztecus Ives, 1891 and pink shrimp Penaeus duorarumBurkenroad, 1931 were estimated using length-frequency data in the hypersaline coastal lagoon, Laguna Madre of Tamaulipas, Mexico. The influence of environmental variables (salinity and temperature) and shrimp body size on the growth of both penaeid species were also evaluated. Shrimps were collected monthly from two fishing zones located at the central part of the lagoon throughout one year. A total of 4458 shrimps were analysed (69.3% P. aztecus and 30.7% P. duorarum) with total lengths (TL) ranging from 50.9 to 131.4 mm in P. aztecus and 59.7 to 134.5 mm in P. duorarum. Mean growth rate (±SD) of P. duorarum (3.10 ±1.78 mm TL per week) was slightly higher than that of P. aztecus (2.71 ±1.37 mm TL per week); however, the interspecific difference was not significant (p&gt;0.05). Growth rates for both the penaeid shrimp species increased as water temperature increased. Additionally, a negative relationship between the growth rate and body length of shrimp was also detected suggesting that the positive effect of water temperature on the increase in shrimp length may be size-dependent.

Two-phase heat transfer in horizontal dimpled/protruded surface tubes with petal-shaped background patterns

Experimental investigations were carried out to measure the average heat transfer coefficient and frictional pressure loss of R410A during condensation and evaporation in five newly-developed dimpled tubes and two smooth tubes. These dimpled tubes were called EHT series tubes enhanced by dimple or protrusion arrays and staggered petal-shaped background patterns on their inner surface. Tests were conducted at three condensation temperatures and two evaporation temperatures; over a mass flux range of 60–450 kg/(m2·s); with an inlet vapor quality of 0.8/0.2 and outlet vapor quality of 0.2/0.8. Among the copper test tubes having the same outer diameter, the 1EHTa tube (dimpled surface tube) showed the highest condensing coefficient and pressure drop under the same test conditions. On the contrary, the superior evaporation heat transfer performance was given by the 1EHTb tube (protruded surface tube). In addition, the positive effects of small tube diameter and low saturation temperature on thermal performance have been confirmed. It was also observed that measured heat transfer coefficient and pressure drop of the copper 1EHTa tube were higher in comparison with the stainless steel one. The main reason could be the low thermal conductivity of stainless steel material. A comparison of heat transfer enhancement in these enhanced tubes has been done. Results indicated that both the copper 1EHTa and 1EHTb tubes provided the satisfactory surface thermal efficiency.

Sr:F co-doping of In2O3 thin film and its dual inhibition effect on trap states to achieve a high stability thin film transistor deposited by solution process

In the paper, excellent stability for a solution-processed SrInOF thin film transistor (TFT) device has been achieved by an ingenious Sr:F co-doping route, which is attributed to the dual inhibition effect on the trap states in the SrInOF system. The metal Sr cations exhibit a stronger binding dissociation energy for Sr–O than for In–O, while the F anions present a similar ionic radius compared to oxygen, which results in a strong suppressive effect on the trap states in the SrInOF system and leads to superior stability. The optimized ΔVTH under the negative bias-illumination stress (NBIS), positive bias stress (PBS) and temperature effect are −0.7 V, 0.8 V and −1.2 V for the superior SrInOF TFT device, compared to −11.6 V (NBIS), 8.1 V (PBS) and −8.0 V (temperature effect) for the initial In2O3 TFT, respectively. Furthermore, F anions can simultaneously substitute for oxygen atoms in the lattice, releasing a free electron to the conduction band, which can enhance the electrical performance of the SrInOF TFT. The µ, VTH, SS and Ion/Ioff for the optimized SrInOF TFT are 14.1 V−1 s−1, 1.51 V, 0.22 V/dec and 2.66 × 107, which fully meets the operational need for TFTs in flat panel displays. It implies that Sr:F co-doping is the perfect method to enhance TFT stability and their electrical performance.

Modulation of the Eelgrass – Labyrinthula zosterae Interaction Under Predicted Ocean Warming, Salinity Change and Light Limitation

Marine infectious diseases can have large-scale impacts when they affect foundation species such as seagrasses and corals. Interactions between host and disease, in turn, may be modulated by multiple perturbations associated with global change. A case in point is the infection of the foundation species Zostera marina (eelgrass) with endophytic net slime molds (Labyrinthula zosterae), the putative agent of eelgrass wasting disease that caused one of the most severe marine pandemics across the North-Atlantic in the 1930s. The contemporary presence of L. zosterae in many eelgrass meadows throughout Europe raises the question whether such a pandemic may re-appear if coastal waters become more eutrophic, warmer and less saline. Accordingly, we exposed uninfected Baltic Sea Z. marina plants raised from seeds to full factorial combinations of controlled L. zosterae inoculation, heat stress, light limitation (mimicking one consequence of eutrophication) and two salinity levels. We followed eelgrass wasting disease dynamics, along with several eelgrass responses such as leaf growth, mortality and carbohydrate storage, as well as the ability of plants to chemically inhibit L. zosterae growth. Contrary to our expectation, inoculation with L. zosterae reduced leaf growth and survival only under the most adverse condition to eelgrass (reduced light and warm temperatures). We detected a strong interaction between salinity and temperature on L. zosterae abundance and pathogenicity. The protist was unable to infect eelgrass under high temperature (27°C) in combination with low salinity (12 psu). With the exception of a small positive effect of temperature alone, no further effects of any of the treatment combinations on the defense capacity of eelgrass against L. zosterae were detectable. This work supports the idea that contemporary L. zosterae isolates neither represent an immediate risk for eelgrass beds in the Baltic Sea, nor a future one under the predicted salinity decrease and warming of the Baltic Sea.

EFFECT OF POSITIVE TEMPERATURES ON THE GLYCOGEN CONTENT IN TRICHINELLA LARVAE

In the present study, the effect of positive temperatures on the content of glycogen, the main reserve polysaccharide of trichinella, which plays an important role in their metabolism, was studied. The concentration of glycogen, determined by the modi-fied method of E.O. Danchenko and A.A. Chirkina (2010), was 0.007 μg per 1 T. nativa larva on the third day of the experiment, which corresponded to the time period for their viability to zero.Trichinosis is a helminthic disease of humans and animals that belongs to the group of dangerous helminth toxic diseases. Due to the fact that trichinella mainly exhibit anoxybiotic metabolism, their main storage substance is glycogen, which they ac-cumulate in significant quantities at the muscular stage of development [3]. Consid-ering the fact that under the influence of positive temperatures, the newly isolated Trichinella larvae exhibit mobility, the mobilization of energy resources, primarily glycogen, to ensure the basal metabolism and motor activity continues until the en-ergy sources are reduced to a critical level. In this study, we established the concen-tration of glycogen in Trichinella nativa larvae in conjunction with the viability index under the influence of elevated temperatures, affecting the intensity of metabolism.

Combined effects of nutritional, biochemical and environmental stimuli on growth performance and fatty acid composition of gilthead sea bream (Sparus aurata).

The reliance of the aquafeed industry on marine resources has to be reduced by innovative approaches in fish nutrition. Thus, a three-factorial approach (fish oil reduced diet, phytochemical genistein, and temperature reduction) was chosen to investigate the interaction of effects on growth performance and tissue omega-3 long chain polyunsaturated fatty acid (LC-PUFA) levels in juvenile sea bream (Sparus aurata, 12.5 ± 2.2 g). Genistein is a phytoestrogen with estrogen-like activity and thus LC-PUFA increasing potential. A decrease in the rearing temperature was chosen based on the positive effects of low temperature on fish lipid quality. The experimental diets were reduced in marine ingredients and had a fish oil content of either 6% dry matter (DM; F6: positive control) or 2% DM (F2: negative control) and were administered in the plain variant or with inclusion of 0.15% DM genistein (F6 + G and F2 + G). The feeding trial was performed simultaneously at 23°C and 19°C. The results indicated that solely temperature had a significant effect on growth performance and whole body nutrient composition of sea bream. Nevertheless, the interaction of all three factors significantly affected the fatty acid compositions of liver and fillet tissue. Most importantly, they led to a significant increase by 4.3% of fillet LC-PUFA content in sea bream fed with the diet F6 + G in comparison to control fish fed diet F6, when both groups were held at 19°C. It is hypothesized that genistein can act via estrogen-like as well as other mechanisms and that the dietary LC-PUFA content may impact its mode of action. Temperature most likely exhibited its effects indirectly via altered growth rates and metabolism. Although effects of all three factors and of genistein in particular were only marginal, they highlight a possibility to utilize the genetic capacity of sea bream to improve tissue lipid quality.