Low Temperature Season Research Articles

Climatic and Catchment-Scale Predictors of Chinese Stream Insect Richness Differ between Taxonomic Groups.

Little work has been done on large-scale patterns of stream insect richness in China. We explored the influence of climatic and catchment-scale factors on stream insect (Ephemeroptera, Plecoptera, Trichoptera; EPT) richness across mid-latitude China. We assessed the predictive ability of climatic, catchment land cover and physical structure variables on genus richness of EPT, both individually and combined, in 80 mid-latitude Chinese streams, spanning a 3899-m altitudinal gradient. We performed analyses using boosted regression trees and explored the nature of their influence on richness patterns. The relative importance of climate, land cover, and physical factors on stream insect richness varied considerably between the three orders, and while important for Ephemeroptera and Plecoptera, latitude did not improve model fit for any of the groups. EPT richness was linked with areas comprising high forest cover, elevation and slope, large catchments and low temperatures. Ephemeroptera favoured areas with high forest cover, medium-to-large catchment sizes, high temperature seasonality, and low potential evapotranspiration. Plecoptera richness was linked with low temperature seasonality and annual mean, and high slope, elevation and warm-season rainfall. Finally, Trichoptera favoured high elevation areas, with high forest cover, and low mean annual temperature, seasonality and aridity. Our findings highlight the variable role that catchment land cover, physical properties and climatic influences have on stream insect richness. This is one of the first studies of its kind in Chinese streams, thus we set the scene for more in-depth assessments of stream insect richness across broader spatial scales in China, but stress the importance of improving data availability and consistency through time.

고군산군도 해역의 식물플랑크톤 군집의 시·공간적 분포 및 출현 환경특성

서해 새만금 방조제에 인접하는 고군산군도 해역에서 2011년 4회 계절별 식물플랑크톤 군집의 시 공간적 분포특성 파악을 위한 현장조사를 실시하였다. 출현한 식물플랑크톤은 56속 104종으로 다양하였으나 기존 서해해역의 출현 종수에 비해 낮았다. 분류군별은 규조류가 60.5%, 와편모조류가 34.6%로 규조류 점유률이 높았다. 현존량은 가을 <TEX>$9.6{\times}10^4cells/L$</TEX>에서 겨울 <TEX>$1.0{\times}10^7cells/L$</TEX>의 범위로 큰 변동 폭과 값으로 겨울과 여름에 높고, 봄과 가을에 낮았다. 우점종은 겨울 Skeletonema costatum-like species, Thalassiosira nordenskioeldii, Dactyliosolen fragillisimus, Chaetoceros debilis, 봄 Guinardia delicatula, 여름 Eucampia zodiacus, Cylindrotheca closterium, Ch. debilis, Ch. curvisetus, 그리고 가을 S. costatum-like species, Ch. debilis, Ch. curvisetus, G. delicatula, Leptocylindrus danicus로 가을과 겨울을 제외하면 계절적 변화가 분명하였다. 또한 서해의 토착 및 일시성 부유종은 39종으로 1980년에 비해 1/3로 감소하였다. Chl-a 농도는 가을 <TEX>$3.82{\mu}g/L$</TEX>에서 여름 <TEX>$13.36{\mu}g/L$</TEX>로 변화하였고, 최대는 여름 <TEX>$44.24{\mu}g/L$</TEX>로 1980년대 서해 최대 <TEX>$50{\mu}g/L$</TEX>에 비하면 9배 가까운 증가를 나타내었다. 다만 Chl-a 농도와 세포밀도의 계절변화 사이에 유의적 관련성은 발견되지 않았다. 주성분분석에 의한 고군산군도 해역의 생물해양학적 특성은 고수온기에는 새만금 수괴, 저수온기에는 금강 수괴에 지배되었고, 중심목과 우상목 규조류의 출현 환경은 서로 다르게 나타났다. 즉 고군산군도 해역은 새만금 방조제 완공 이후 급격하게 부영양화가 진행되어, 현재 내만성 환경으로 진행되어 있는 것으로 판단되었다. This study examined the spatio-temporal distributions of the phytoplankton community in the coastal waters of Gogunsan Islands (CoWGIs), West Sea of Korea, from January to September 2011. A total of 104 species of phytoplankton belonging to 56 genera were identified. This was low compared to the surrounding seas of the West Sea. In particular, diatoms and dinoflagellates comprised 60.5% and 34.6%, respectively, and it was most diverse in autumn. The standing crops fluctuated from <TEX>$9.6{\times}10^4cells/L$</TEX> to <TEX>$1.0{\times}10^7cells/L$</TEX>. This was high in winter and summer and low in spring and autumn. The seasonal dominant species were Skeletonema costatum-like species, Thalassiosira nordenskioeldii, Dactyliosolen fragillisimus, and Chaetoceros debilis in winter, Guinardia delicatula in spring, Eucampia zodiacus, Cylindrotheca closterium, Ch. debilis, and Ch. curvisetus in summer, and S. costatum-like species, Ch. debilis, Ch. curvisetus, G. delicatula, and Leptocylindrus danicus in autumn. The total number of autochthonous and tychopelagic species was 39 species. This showed a 1/3 (33.3%) decrease compared to the 1980's. The chlorophyll a concentration fluctuated from <TEX>$3.82{\mu}g/L$</TEX> in autumn to <TEX>$13.36{\mu}g/L$</TEX> in summer. The bio-oceanographic characteristics of the CoWGIs based on principle component analysis (PCA) showed that it was dominated by the Saemangeum water mass in the high temperature season and by the Geum River water mass in the low temperature season. In other words, there has been a conversion to a closed inner bay followed by the dramatic progress of eutrophication, even in the CoWGIs after completion of the Saemangeum embankment.

Frost Damage Mechanism Analysis and Preventive Measures of Bridge

In order to guarantee the safety and smooth of road traffic in low temperature season, deicing salt is usually adopted to solute the problem of bridge deck snow. However, the frequent use of de-icing salt causes the salt frozen erosion damage of concrete, at the same time, it induces to internal corrosion of steel bars and concrete material performance, furthermore, it will also result in the bridge structure durability degradation, shorten the service life of the bridge. Aiming at this phenomenon, this paper analyzes the mechanism of concrete frost damage, and put forward the corresponding prevention measures.

Effects of elevated temperature postharvest on color aspect, physiochemical characteristics, and aroma components of pineapple fruits.

In this work, 2 separate experiments were performed to describe the influence of elevated temperature treatments postharvest on the color, physiochemical characteristics and aroma components of pineapple fruits during low-temperature seasons. The L* (lightness) values of the skin and pulp of pineapple fruits were decreased. The a* (greenness-redness) and b* (blueness-yellowness) values of the skin and pulp were all markedly increased. The elevated temperature significantly increased the contents of total soluble solids (TSS) and slightly affected contents of vitamin C (nonsignificant). Titratable acidity (TA) of pineapple fruits were notably decreased, whereas the values of TSS/TA of pineapple fruits were significantly increased. The firmness of the pineapple fruits decreased and more esters and alkenes were identified. The total relative contents of esters were increased, and the total relative contents of alkenes were decreased.

Seasonal and genotypic changes in escherichia coli phylogenetic groups in the Yeongsan River basin of South Korea.

With 3,480 E. coli strains isolated from the Yeongsan River basin, South Korea, correlations between phylogenetic groups and horizontal fluorophore enhanced rep-PCR (HFERP) genotypes were examined, and environmental factors affecting E. coli phylogenetic groups in the river water were determined. Interestingly, multidimentional scaling (MDS) analyses based on HFERP DNA fingerprint data indicated that E. coli in phylogenetic groups A and B1 were uniquely clustered. Results of self-organized maps (SOMs) analyses also indicated that E. coli phylogenetic groups were seasonally affected by water temperature, with greater occurrences of phylogenetic groups A and B1 in low and high temperature seasons, respectively. The presence of E. coli in phylogenetic groups A and B1 were inversely related. Furthermore, redundancy analysis (RDA) revealed that phylogenetic group B1 correlated positively with temperature, strain diversity, and biochemical oxygen demand (BOD) but negatively with phylogenetic group A. Results of this study indicated that while E. coli strains could be clustered based on their genotypes and environment conditions, their phylogenetic groups did not change in relation to the same conditions. The distributional differences of phylogenetic groups among E. coli populations in different environments may be caused by different genomic adaptability and plasticity of E. coli strains belonging to each phylogenetic group. Although several previous studies have reported different E. coli ecological structures depending on their origins, this study is a first description of the specific environmental factors affecting E. coli phylogenetic groups in river water.

Toward production of microalgae in photobioreactors under temperate climate

The issue of presented paper is the cultivation of microalgae in temperate climate where the problems are: too low temperature and short vegetation season. The solution is to increase the efficiency of utilization of nutrients under unfavorable climate conditions. The cultivation could be performed in the closed systems, with the application of better source of light to lengthen the growing season and greenhouse to keep high temperature even during the night. The aim of the work was to choose the best method for growth, as well as harvesting the biomass to obtain microalage that can be used in the human diet, animal feed or for industrial applications. The description of available photobioreactors was provided. Different aspects of photobioreactors engineering were discussed: construction, mixing, separation, as well as the overall technology of microalgal biomass cultivation. Two novel photobioreactors were also proposed: column in large-laboratory scale with the capacity of 0.5m3 and stirred tank in semi-technical scale with the capacity of 10m3 located under the glasshouse. The strain of Spirulinamaxima was cultivated in the new photobioreactors, because of the simplicity of separation as well as the possibility to maintain the monoculture conditions. A higher growth rate was obtained in pilot-scale reactor (0.4301/day) at a rate comparing to a column reactor (0.2991/day), although the ratio A/V of 10m3 reactor was 22 times smaller than the capacity of the reactor with the capacity 0.5m3. After 45 days of culture in the column photobioreactor, about 0.3kg of dry mass, and in the reactor with the capacity 10m3 about 3kg dry mass, was obtained.

Fossil palm beetles refine upland winter temperatures in the Early Eocene Climatic Optimum.

Eocene climate and associated biotic patterns provide an analog system to understand their modern interactions. The relationship between mean annual temperatures and winter temperatures-temperature seasonality-may be an important factor in this dynamic. Fossils of frost-intolerant palms imply low Eocene temperature seasonality into high latitudes, constraining average winter temperatures there to >8 °C. However, their presence in a paleocommunity may be obscured by taphonomic and identification factors for macrofossils and pollen. We circumvented these problems by establishing the presence of obligate palm-feeding beetles (Chrysomelidae: Pachymerina) at three localities (a fourth, tentatively) in microthermal to lower mesothermal Early Eocene upland communities in Washington and British Columbia. This provides support for warmer winter Eocene climates extending northward into cooler Canadian uplands.

Thermal energetics of the New-Guinean moss-forest rat (Rattus niobe) in comparison with other tropical murid rodents

The thermal energetics of rodents from cool, wet tropical highlands are poorly known. Metabolic rate, body temperature and thermal conductance were measured in the moss-forest rat, Rattus niobe (Rodentia), a small murid endemic to the highlands of New Guinea. These data were evaluated in the context of the variation observed in the genus Rattus and among tropical murids. In 7 adult R. niobe, basal metabolic rate (BMR) averaged 53.6±6.6mLO2h−1, or 103% of the value predicted for a body mass of 42.3±5.8g. Compared to other species of Rattus, R. niobe combines a low body temperature (35.5±0.6°C) and a moderately low minimal wet thermal conductance cmin (5.88±0.7mLO2h−1°C−1, 95% of predicted) with a small size, all of which lead to reduced energy expenditure in a constantly cool environment. The correlations of mean annual rainfall and temperature, altitude and body mass with BMR, body temperature and cmin were analyzed comparatively among tropical Muridae. Neither BMR, nor cmin or body temperature correlated with ambient temperature or altitude. Some of the factors which promote high BMR in higher latitude habitats, such as seasonal exposure to very low temperature and short reproductive season, are lacking in wet montane tropical forests. BMR increased with rainfall, confirming a pattern observed among other assemblages of mammals. This correlation was due to the low BMR of several desert adapted murids, while R. niobe and other species from wet habitats had a moderate BMR.

Purification effects of two eco-ditch systems on Chinese soft-shelled turtle greenhouse culture wastewater pollution

The present study used an eco-ditch system that employed Eichhornia crassipes, Bacillus subtilis, and Bellamya aeruginosa (E-B-B) during the summer and fall (high temperature) seasons and a second eco-ditch system that employed Elodea nuttallii, a compound microbial preparation called "EM bacteria", and Hypophthalmichthys molitrix (E-E-H) during the winter and spring (low temperature) seasons successively to purify the discharged wastewater produced by Chinese soft-shelled turtle greenhouse cultivation. The wastewater was sampled, and the dynamic changes in the major nutrient pollutant indicators over several months were analysed. After the E-B-B and E-E-H eco-ditch purification systems were operated for nearly 140days each, the following results were observed: the total nitrogen (TN) removal rates in the wastewater were 75% and 69%, respectively; the total phosphorus (TP) removal rates were 82% and 86%, respectively; the NH4 (+)-N removal rates were 91% and 75%, respectively; the chemical oxygen demand (CODcr) decreased 54% and 44%, respectively; the dissolved oxygen (DO) contents increased nearly 3 to 4 times; and the wastewater was maintained at neutral or alkaline pH values. The wastewater physical traits gradually changed from being yellow, brown, and muddy to being pale yellow, slightly turbid, and odourless. Both eco-ditch systems were observed to have a relatively favourable effect on the purification of Chinese soft-shelled turtle aquaculture wastewater. The continuous use of both eco-ditch systems could result in a year-round purification effect on Chinese soft-shelled turtle greenhouse aquaculture wastewater; therefore, this method has good prospects for promotion and application.

Alimentación de dos especies de anfibios (Anura: Hylidae) en la estación de bajas temperaturas y su relación con la acumulación de energía en Santa Fe, Argentina

Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina. In environments with thermal and pluvial seasonality such as those of the Middle Paraná River floodplain (Province of Santa Fe, Argentina), most amphibian species reproduce during the warm season and drastically diminish their activity during winter. Even though, a few species remain active during the cold season, such as Hypsiboas pulchellus that has its reproductive peak during the autumn-winter period (and the consequent energy demand). The objective of this study was to analyze and compare the feeding and development of fat bodies during the low temperature season for H. pulchellus and Dendropsophus nanus. We analyzed entire gastrointestinal tract contents of both species (H. pulchellus = 110 specimens; D. nanus = 114 specimens) and applied an index (IRI%) that combines prey abundance, volume and frequency to describe frogs diets; we used fat bodies weights as indicators of stored energy reserves. We compared diet between species with a niche overlap index (Ojk: 0-1) and used null models to ascribe statistical significance to evaluate overlap; and we analyzed variation in empty guts proportions through months and between species. Also, using ANCOVAs we explored differences in fat bodies, number and volume of prey consumed along months, between species and sexes. The most important preys in H. pulchellus diet during the cold season were Araneae (IRI% = 34.96), Chironomidae (IRI% = 33.08), Tipulidae (IRI% = 11.44) and Gryllidae (IR1% = 7.31); while for D. nanus, Chironomidae (IR1% = 48.14), Tipulidae (IRI% = 18.41), Psychodidae (IRI% = 7.44) and Araneae (IRI% = 7.34). Diet overlap between species was elevated (Ojk=0.78) and higher than expected by chance (mean simulated indices: Ojk = 0.04; p[observed > or = expected]<0.01; p[observed < or = expected] = 1). In H. pulchellus there was a monthly variation in number of prey per gut, while in D. nanus there was a difference in fat bodies development between sexes. Fat bodies development, number of prey per gut and preys volume also varied between species. Despite diet similarity between H. pulchellus and D. nanus, each species showed a different strategy to accumulate energy and support their activity during the cold season. The low rate of gastrointestinal emptiness in H. pulchellus (< 10% in any analyzed month) together with the poor development of their fat bodies, allows us to point out that, to sustain the breeding elevated energy demands, this species continues with a high feeding rate even at the low temperatures of cold season. On the other hand, the rate of gastrointestinal emptiness of D. nanus was higher than that of H. pulchellus (May = 17.24%, July = 22.22% and August = 35.71%), while their fat bodies were well developed. Thus, D. nanus would depend more on their stored reserves to sustain the energy demands of being active during the low temperatures season and hence would reach the reproductive season in spring-summer in good body condition.

배양액의 농도가 딸기 '매향' 생육, 과실의 품질 및 수량에 미치는 영향

국내에서 육성되어 수출딸기의 주역인 '매향' 딸기의 수경재배에서 적절한 배양액 농도를 구명하고자 하였다. 2010년 9월 20일에 코코피트를 충진한 수경재배 벤치에 정식하고, 야마자키 조성 딸기배양액을 이용하여 처리별로 EC를 0.6, 0.8, 1.2, <TEX>$1.8dS{\cdot}m^{-1}$</TEX>로 급액하였다. 지상부 생육은 배양액 농도 차이에 따라 일부 차이를 나타내긴 하였지만 그 차이는 미미하여 큰 영향을 받지는 않는 것으로 생각되었다. 과장은 정화방에서는 EC 0.8과 <TEX>$1.2dS{\cdot}m^{-1}$</TEX>처리에서 가장 길었고 <TEX>$1.8dS{\cdot}m^{-1}$</TEX>에서 가장 짧았다. 제 2화방에서는 EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX>처리에서 가장 짧았고 나머지 처리 간에는 유의한 차이가 없었다. 제 3화방은 정화방과 동일한 경향을 나타내었으며, 제 4화방은 처리 간에 통계적으로 유의한 차이가 없었다. 과경은 정화방과 제 1화방에서는 처리 간에 유의한 차이가 없었으며, 제 3화방에서는 EC 1.8의 높은 농도보다는 0.6의 가장 낮은 농도에서 과경이 더 길었다. 제 4화방에서는 EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX>처리에서 가장 과경이 짧았으며 다른 처리 간에는 유의한 차이가 없었다. 과중은 정화방에서는 EC 1.2와 <TEX>$0.8dS{\cdot}m^{-1}$</TEX>에서 가장 컸고 높은 농도의 EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX>에서 낮았다. 제 2화방에서는 EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX>에서 가장 낮았으며 다른 농도 간에는 유의한 차이가 없었다. 제 3화방에서는 처리 간에 유의한 차이가 없었으며, 제 4화방에서는 0.8에서 <TEX>$1.8dS{\cdot}m^{-1}$</TEX>까지는 차이가 없었지만 낮은 농도의 <TEX>$0.6dS{\cdot}m^{-1}$</TEX>보다는 높은 농도의 <TEX>$1.8dS{\cdot}m^{-1}$</TEX>의 과중이 월등하게 낮았다. 과실 내의 가용성 고형물은 각 화방에 따라서 처리 간에 약간의 변화는 있었지만 전반적으로 EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX> 처리에서 가장 높은 경향을 나타내었다. 특히 제 3화방에서는 EC 0.6에서 <TEX>$1.8dS{\cdot}m^{-1}$</TEX>까지 배양액의 농도가 높아짐에 따라 가용성 고형물의 함량이 순차적으로 낮아지는 것을 볼 수 있었다. 딸기 '매향'의 수경재배에서 배양액의 EC 관리는 온도가 낮은 저온기에는 EC <TEX>$0.8-1.2dS{\cdot}m^{-1}$</TEX> 농도로 관리하는 것이 좋을 것으로 생각되었다. 이러한 결과는 딸기 수경재배에서 유용하게 활용될 것으로 기대된다. Experiments were conducted to investigate the optimum concentration of nutrient solution for strawberry 'Maehyang' bred domestically for exportation in hydroponics. Nutrient solutions for strawberry, which was made by Yamazaki, were supplied electrical conductivity (EC) 0.6, 0.8, 1.2, and <TEX>$1.8dS{\cdot}m^{-1}$</TEX> after planting on cocopeat medium during the experiment period. Growth of shoot of strawberries did not show any statistical differences among treatments. Fruit length showed the longest in EC 0.8 and <TEX>$1.2dS{\cdot}m^{-1}$</TEX>, followed by 0.6 and <TEX>$1.8dS{\cdot}m^{-1}$</TEX> in the first and third cluster. It showed the shortest in EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX> in the second cluster but there were no significant differences among treatments in the fourth cluster. Fruit diameter did not show significant differences among treatments in the first and second cluster but was the longest in the lowest concentration EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX> in the third cluster. The shortest was in EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX> in the fourth cluster. The heaviest mean fruit weight appeared in EC 0.8 and <TEX>$1.2dS{\cdot}m^{-1}$</TEX>, and the lightest was in EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX> in the first cluster and also lightest in EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX> but no significant differences was found among other treatments in the second & third cluster. Also the fruit weight was significantly light in plants grown in EC <TEX>$1.8dS{\cdot}m^{-1}$</TEX> than <TEX>$0.6dS{\cdot}m^{-1}$</TEX> in the fourth cluster. Soluble solids content of fruit was the highest in EC <TEX>$0.6dS{\cdot}m^{-1}$</TEX> in all cluster. As a result, we came to the conclusion that the optimum EC for strawberry 'Maehyang' was EC 0.8 - <TEX>$1.2dS{\cdot}m^{-1}$</TEX> during low temperature season. This result will be utilized as an indicator for strawberry hydroponics.

The effects of dredging on nitrogen balance in sediment-water microcosms and implications to dredging projects

Sediment dredging is a controversial technology for eutrophication control. It is necessary to understand its environmental effectiveness and mechanisms. In this study, sediments from un-dredged (UDR), fresh-dredged (FDR) and post-dredged (PDR, 3 years later) regions of Dongqian Lake were collected to compose sediment-water microcosms for evaluating the effects of dredging on nitrogen cycling. From 0 to 19 days, ammonia in the overlying water greatly increased in UDR (603.1%) and FDR (269.3%), but slightly in PDR (88.7%). The increase of ammonia concentration in water was negatively correlated with DO which was higher in two dredged groups than that in un-dredged groups. These results suggest that dredging could lead to ammonia release to water column in a short term, while ammonia release risk is low few years after dredging. In addition to high DO content, high Eh values, low pH and sediment porosity in two dredged groups may weaken the attenuation of nitrate. TN contents in both sediment and overlying water indicate that nitrogen lost in un-dredged group while had no significantly change in two dredged groups, indicating the ability of nitrogen removal in dredged groups was weakened. Our study suggests that dredging may have potentials to weaken nitrate and/or nitrogen removal from lake systems over years. For this, we should pay more attention on dredging area in dredging projects. Moreover, dredging is better to be conducted in low temperature seasons after blocking external nutrient loadings.

Seasonality, montane beta diversity, and Eocene insects: Testing Janzen's dispersal hypothesis in an equable world

We test Janzen's (1967) hypothesis that the low temperature seasonality in the modern tropics accounts for increased local species turnover (beta diversity) across montane landscapes relative to those of the more seasonal Temperate Zone. In the Eocene, low seasonality extended beyond the hot tropics to Polar Regions, therefore, its effects on montane dispersal ability should have been decoupled from low latitude. We sampled fossil insect communities across the Okanagan Highlands: a thousand kilometer transect of temperate, low temperature seasonality, higher mid-latitude Eocene uplands of far-western North America. We find high species turnover, supporting a prime role of temperature fluctuation in controlling montane beta diversity. This high upper mid-latitude montane endemism is consistent with greater Eocene global biodiversity.

Study on the Drafting and Early-Warning of Temperature Double-Control Index of Different Sections & Periods of Concrete Block

Although real-time tracking and feedback were carried out for the dam concrete construction process, there was still certain blindness in the construction units. The temperature double-control index, which is the allowable temperature and temperature gradient under typical age before concrete block reaching its maximum temperature, was proposed in this paper on the basis of the analysis of measured temperature process curves of concrete blocks. The probabilistic method was applied to draft the temperature double-control index of different sections and periods based on the measured temperature process curve of the poured block of a constructing extra-high arch dam in southwest China. Furthermore, the prediction model was also provided and applied in the dynamic feedback of new pouring block. It is demonstrated by the practice that the prediction model proposed in this paper has better pertinence and maneuverability for the construction units to control the maximum temperature of concrete block, i.e. the maximum temperature in high temperature season and in low temperature season are both controllable.

GLOBAL PATTERNS OF LEAF DEFENSES IN OAK SPECIES

Plant defensive traits drive patterns of herbivory and herbivore diversity among plant species. Over the past 30 years, several prominent hypotheses have predicted the association of plant defenses with particular abiotic environments or geographic regions. We used a strongly supported phylogeny of oaks to test whether defensive traits of 56 oak species are associated with particular components of their climatic niche. Climate predicted both the chemical leaf defenses and the physical leaf defenses of oaks, whether analyzed separately or in combination. Oak leaf defenses were higher at lower latitudes, and this latitudinal gradient could be explained entirely by climate. Using phylogenetic regression methods, we found that plant defenses tended to be greater in oak species that occur in regions with low temperature seasonality, mild winters, and low minimum precipitation, and that plant defenses may track the abiotic environment slowly over macroevolutionary time. The pattern of association we observed between oak leaf traits and abiotic environments was consistent with a combination of a seasonality gradient, which may relate to different herbivore pressures, and the resource availability hypothesis, which posits that herbivores exert greater selection on plants in resource-limited abiotic environments.

Selection of Suitable Species of Chlorella, Nannochloris, and Nannochloropsis in High- and Low-Temperature Seasons for Mass Culture of the Rotifer Brachionus plicatilis

To find seasonally optimal microalgae for mass culture of the rotifer Brachionus plicatilis, the growth rates of 12 microalgal species (two marine Chlorella spp., five marine Nannochloris spp., two marine Nannochloropsis spp., one estuarine Nannochloropsis sp., and two estuarine Chlorella spp.) were compared at 25°C at 15 psu and 30 psu. Among these, six species showing high growth rates were chosen and examined again at high (30°C and 32°C) and low (10°C) temperatures. Their amino and fatty acids and the dietary value of the rotifers that fed on each microalgal species were examined. Nannochloris sp. (KMMCC-119) and Chlorella vulgaris (KMMCC-120) showed the highest growth rates at temperatures over 30 o C and at 10°C, respectively. The growth rate of Nannochloris was higher than those of Chlorella and Nannochloropsis at high temperatures, but lower than those of the latter at low temperatures. The growth rate of rotifers fed on Nannochloropsis was highest and that of those fed on Chlorella was lowest. Levels of eicosapentaenoic acid and docosahexaenoic acid were highest in Nannochloropsis and lowest in Nannochloris. However, total amino acid content was highest in Nannochloris and lowest in Chlorella. In conclusion, Nannochloropsis sp. (KMMCC-33) was the best microalgal species for the mass culture of the rotifer. However, during high- or low-temperature seasons in which Nannochloropsis does not grow well, Nannochloris spp. (KMMCC-119, 395) and C. vulgaris (KMMCC-120) would adequately replace Nannochloropsis sp. (KMMCC-33).

배합사료의 수침과 공급량이 넙치(Paralichthys olivaceus)의 성장, 혈액 및 조직 성상에 미치는 영향

Two consecutive feeding trials investigated the effects of feeding rate and pellet expansion by water-soaking on the growth performance, blood components and histology of olive flounder Paralichthys olivaceus. The first two experiments were carried out to determine the effects of pellet expansion and feeding rate. In the first experiment, growth performance, feed utilization and survival of fish were not significantly affected by pellet expansion for six weeks. There were no significant differences in hematocrit, hemoglobin, aspartate aminotransferase, alanine aminotransferase, glucose and total protein of fish fed the expanded pellet. However, whole-body lipid content of fish in the non-expanded group was significantly higher than that in the expanded group. Histological analysis of the anterior intestine revealed that fish in the expanded group had shorter and smaller mucous folds. These results indicate that pellet expansion had no beneficial effect in terms of growth performance, feed utilization and fish health. In the second experiment, weight gain and feed efficiency were significantly increased as feeding rate increased from 0 to 2.5% body weight per day (BW/d), but there were no significant differences in weight gain or feeding efficiency in fish fed the expanded pellet at ratios of 2.5% BW/d and satiation for three weeks. Plasma aspartate aminotransferase activity of fish fed the expanded pellet at a ratio of 2.5% was significantly lower than that of starved fish. Histological analysis of the anterior intestine revealed that fish in the 0% group had shorter mucous folds. Broken-line regression analysis suggested that the optimum juvenile olive flounder feeding rate was 3.5% BW/d during the low temperature season (<TEX>$16-17^{\circ}C$</TEX>).

Regulating Strategies of Strengthening Nitrogen Removal for Low-Carbon Wastewater in Reversed A&lt;sup&gt;2&lt;/sup&gt;/O Process

According to the ineffective denitrification and the initial controlling technique flaws for low-carbon source in reversed A2/O process, and full scale experimental studies were conducted to strengthen denitrification at normal and low temperature days in 2008~2010, to ensure the best conditions of biological denitrification and promote the stable and efficient operation of the system. The results showed that in normal temperature seasons of 2008, after shortening the HRT of the primary sedimentation tank to 1/3 of design value, improving the MLSS to 4500mg/L, setting the first section of the aerobic zone as the denitrification transition section and improving the reflux ratio, available carbon source was increased by 15%, the effluent NH3-N was 2.5mg / L and the removal rate was 90%, the effluent TN was 17 mg/L and the removal rate was increased to 54% and unit power consumption was reduced by 15% to 0.22Kw•h/m3.At low temperature seasons of 2008~2009,by improving the MLSS to 6000mg/L, extending the sludge age to enrich a large number of nitrification and denitrification bacteria, controlling DO at about 1.2mg / L in the aerobic zone and so on, the effluent NH3-N was 3 mg / L and the removal rate was 88%, the effluent TN was 15.5 mg/L and the removal rate was 62%. In low temperature of 2009 ~2010, besides the same measures as before, adding a blender in the first section of the aerobic zone to provide a better anoxic environment for denitrification and to improve nitrogen removal, the effluent NH3-N was 3 mg / L and the removal rate was 87%, the effluent TN was 13.5 mg/L and the removal rate was 66%.

Role of Rbp1 in the Acquired Chill-Light Tolerance of Cyanobacteria

Synechocystis sp. strain PCC 6803 cultured at 30°C losses viability quickly under chill (5°C)-light stress but becomes highly tolerant to the stress after conditioning at 15°C (Y. Yang, C. Yin, W. Li, and X. Xu, J. Bacteriol. 190:1554-1560, 2008). Hypothetically, certain factors induced during preconditioning are involved in acquisition of chill-light tolerance. In this study, Rbp1 (RNA-binding protein 1) rather than Rbp2 was found to be accumulated during preconditioning, and the accumulation of Rbp1 was correlated with the increase of chill-light tolerance. Inactivation of its encoding gene rbp1 led to a great reduction in the acquired chill-light tolerance, while ectopic expression of rbp1 enabled the cyanobacterium to survive the chill-light stress without preconditioning. Microarray analyses suggested that the Rbp1-dependent chill-light tolerance may not be based on its influence on mRNA abundance of certain genes. Similarly to that in Synechocystis, the Rbp1 homologue(s) can be accumulated in Microcystis cells collected from a subtropic lake in low-temperature seasons. Rbp1 is the first factor shown to be both accumulated early during preconditioning and directly involved in development of chill-light tolerance in Synechocystis. Its accumulation may greatly enhance the overwintering capability in certain groups of cyanobacteria.

Dietary Effects of the Protease Treatments of Fish Meal on the Growth, Feed Efficiency, and Protein Digestibility of Yellowtail During Low Temperature Season

Dietary Effects of the Protease Treatments of Fish Meal on the Growth, Feed Efficiency, and Protein Digestibility of Yellowtail During Low Temperature Season