Winter Dry Season Research Articles

Blue intensity from a tropical conifer’s annual rings for climate reconstruction: An ecophysiological perspective

We developed Blue Intensity (BI) measurements from the crossdated ring sequences of Fokienia hodginsii (of the family Cupressaceae) from central Vietnam. BI has been utilized primarily as an indirect proxy measurement of latewood (LW) density of conifers (i.e., LWBI) from high latitude, temperature-limited boreal forests. As such, BI closely approximates maximum latewood density (MXD) measurements made from soft x-ray. The less commonly used earlywood (EW) BI (EWBI) represents the minimum density of EW and is influenced by the lighter pixels from the vacuoles or lumens of cells. The correlation of our BI measurements with climate, strongest for EWBI, rivals that for total ring width (RW), and we demonstrate that it can be successfully employed as an independent predictor for reconstruction models. EWBI exhibits robust spatial correlations with winter and spring land temperature, sea surface temperature (SST) over the regional domain of ENSO, and the Standardized Precipitation Evapotranspiration Index (SPEI) over Indochina. However, in order to mitigate the effects of color changes at the heartwood – sapwood boundary we calculated ΔBI (EWBI-LWBI), and it too exhibits a significant (p < 0.05), temporally stable response to prior autumn (Oct-Nov) rainfall and winter (December to April) dry season temperature. We interpret this response as reflecting a potential cavitation defense by reducing lumen diameter as a means to safeguard hydraulic conductivity in the stem, and to prevent the xylem from imploding due to negative pressure. This study has wide implications for the further use of BI from the global tropics, though it is unclear how many tropical tree species will be appropriate for use. It seems very likely that other wood anatomical measurements can be combined with BI and RW for climate reconstruction.

Growth and wool production of sheep reared at highland of Nepal

Sheep farmers lived in high altitude of Nepal have limited options of supplying roughages in winter season which is resulting severe feed deficit in these periods. Quality roughages like hay and other dried cereal stalks are not sufficiently available in the areas to mitigate the feed deficit in dry harsh winter. Therefore, the study was conducted to evaluate the effects of commonly practiced feeding system on growth and wool production of sheep in winter season. The research was performed at Sheep and Goat Research farm, Jumla, Nepal which is located at 2700 meters above sea level. The animals were supplied with three different rations viz (i) adlibitum oat hay with concentrate feed @ 1% of body weight;(ii) adlibitum conventional hay with concentrate feed @1% of body weight, and (iii) grazing in moderate pasture with concentrate feed @ 1% of body weight. The differences among the treatments were found significant ((p&lt;0.05) changes in terms of average daily weight gain and total weight gain, while wool length and wool production were not significantly different (p&gt;0.05) among the treatments. The treatment of feeding oat hay with concentrate @ 1% of body weight had yielded highest body weight gain. The result of the study revealed that feeding oat hay was more profitable in comparison to conventional system of grazing and feeding conventional hay. Inclusion of oat hay on the sheep diet in dry harsh winter season could make substantial improvement in the body weight gain of the sheep in the high altitude of Nepal.Bang. J. Anim. Sci. 2017. 46 (3): 159-163

Hydrological alterations as the major driver on environmental change in a floodplain Lake Poyang (China): Evidence from monitoring and sediment records

Abstract Due to the lack of long-term records on shallow lake environmental change, knowledge of the processes and mechanisms behind the limnological response of many shallow floodplain lakes to hydrological alterations and nutrient loading is often limited. We examined seasonal monitoring data and a dated sediment core from Lake Poyang, a large floodplain lake located on the Yangtze floodplain in the SE China. Multivariate analysis based on contemporary data (diatoms and water quality) revealed that the seasonal changes in the diatom assemblage of the lake were correlated with water temperature and Secchi depth (SD), although the weak spatial effect was not negligible. During the dry winter season, low water temperature, low SD, and high nutrient levels, were accompanied by high abundances of planktonic Aulacoseira species along with Stephanodiscus hantzschii, a species well adapted to cold and eutrophic waters. During the summer wet season, however, when water temperature and SD were high and nutrient levels low, benthic and epiphytic diatoms, such as the genus Achnanthes, dominated. Sediment records of diatoms and geochemistry were used to estimate long-term variation in the ecological condition of the lake. During the past ~60 years, the lake has shifted from a natural hydrologically connected, oligotrophic lake dominated by benthic and epiphytic diatoms to a poorly hydrologically connected, eutrophic state driven by nutrient-tolerant planktonic and eutrophic diatoms. Furthermore, our results indicate that the proposed Poyang dam may severely affect the water quality and ecosystem of the lake by altering its seasonal hydrology.

Drivers of waterbird communities and their declines on Yangtze River floodplain lakes

The seasonally flooded Yangtze Valley Floodplain wetlands of China are globally important for wintering waterbirds in the East Asian-Australasian Flyway. These birds have declined in the last 60years, so understanding factors shaping waterbird distribution and abundance patterns is critical for their conservation. We applied linear mixed models to investigate the effects of climate, winter water area and inundation area (the difference between maximum flooded and winter dry season water area) on waterbird abundance and diversity at 72 lakes in 2005 and 2016. Neither winter water area nor climate featured in the best models, rather inundation area was the key determinant of waterbird abundance and diversity. Future water abstraction and land claim will therefore have greater impacts on waterbird abundance and diversity than likely climate change effects. Significant declines in waterbird abundance and diversity between 2005 and 2016 were not explained by modelled variables and there was no reduction in wetland inundation areas to explain these declines, confirming other factors were responsible. These potentially include declining wetland quality affecting carrying capacity (e.g. flooding phenology, disturbance, habitat loss and degradation, declining water quality caused by eutrophication and pollution) and/or factors limiting migratory waterbird populations at other stages in their life cycle elsewhere. The studied Yangtze lakes are amongst the best for wintering waterbirds and many are protected for their biodiversity, suggesting such protection cannot fully safeguard these internationally shared populations when threatened by other, currently unknown factors. This confirms the urgent need for more research to safeguard these ephemeral lake systems for their global biodiversity significance.

Identification of relationships between climate indices and long-term precipitation in South Korea using ensemble empirical mode decomposition

Climate indices characterize climate systems and may identify important indicators for long-term precipitation, which are driven by climate interactions in atmosphere-ocean circulation. In this study, we investigated the climate indices that are effective indicators of long-term precipitation in South Korea, and examined their relationships based on statistical methods. Monthly total precipitation was collected from a total of 60 meteorological stations, and they were decomposed by ensemble empirical mode decomposition (EEMD) to identify the inherent oscillating patterns or cycles. Cross-correlation analysis and stepwise variable selection were employed to select the significant climate indices at each station. The climate indices that affect the monthly precipitation in South Korea were identified based on the selection frequencies of the selected indices at all stations. The NINO12 indices with four- and ten-month lags and AMO index with no lag were identified as indicators of monthly precipitation in South Korea. Moreover, they indicate meaningful physical information (e.g. periodic oscillations and long-term trend) inherent in the monthly precipitation. The NINO12 indices with four- and ten- month lags was a strong indicator representing periodic oscillations in monthly precipitation. In addition, the long-term trend of the monthly precipitation could be explained by the AMO index. A multiple linear regression model was constructed to investigate the influences of the identified climate indices on the prediction of monthly precipitation. Three identified climate indices successfully explained the monthly precipitation in the winter dry season. Compared to the monthly precipitation in coastal areas, the monthly precipitation in inland areas showed stronger correlation to the identified climate indices.

Tree legumes-temperate grass agroforestry system effects on inorganic soil nitrogen as ecosystem services provision for smallholder farming systems in South Africa

ABSTRACTNitrogen is an essential macro-nutrient for plant growth and is indispensable for high agricultural food productivity and quality. Shortage of good quality forage under the dry winter season and low soil fertility conditions are the major constraints in rural farming systems in the Moist Tall Grassveld of the Upper Thukela, South Africa. The effect of legumes on inorganic soil nitrogen was assessed in an agroforestry trial (Leucaena leucocephala (Lam.) De Wit, Acacia karroo Hayne, Dactylis glomerata L., Festuca arundinacea Schreb.), by soil sampling method. In the agroforestry trial, total inorganic soil nitrogen accumulation was significantly greater under intercropping than under sole crop treatments and, irrespective of the treatments, significantly more nitrate than ammonium nitrogen was measured. The study demonstrated that intercropping grasses with tree legumes could provide important ecosystem services of nitrogen supply in the soil. The results suggested that introducing legume intercrops might constitute a relevant cropping strategy to improve the soil fertility status with regard to nitrogen while at the same time providing forage in smallholder farming systems in South Africa’s Moist Tall Grassveld regions.

Modeling calcification periods of &amp;lt;i&amp;gt;Cytheridella ilosvayi&amp;lt;/i&amp;gt; from Florida based on isotopic signatures and hydrological data

Abstract. The isotopic signatures of ostracod shells are the result of the temperature and composition of their host water and the phenology and ecology of the target species. Investigations addressing the influence of site-specific environmental variations on the isotopic ranges of ostracod shells are still rare but can provide important information on habitat-dependent variations and may signify a seasonally restricted timing of calcification periods. Here we present isotopic signatures (δ18Oostr, δ13Costr) of living Cytheridella ilosvayi (Ostracoda) and physical, chemical, and isotopic (δD, δ18Owater, δ13CDIC) compositions of 14 freshwater habitats (rivers, lakes, canals, marshes, sinkholes) in South Florida from winter 2013 and summer 2014. We also present instrumental data of river temperatures and δ18O of precipitation (δ18Oprec) from this region. The physicochemical and isotopic compositions of the selected sites characterize the different habitats and show the influence of the source water, biological activity, and duration of exposure to the surface. Mean δ18Oostr and δ13Costr signatures of C. ilosvayi shells correlate well with the isotopic composition of their host waters. Within-sample variabilities in repeated isotopic measurements of single ostracod shells reflect habitat-dependent ranges. The similarly high range of ostracod δ18O in rivers and one marsh sample indicates that both temperature and δ18Oprec are responsible for their variation in the whole study area. Rivers and canals, which are predominantly influenced by the input and mixing of inorganic carbon from the catchment, show smaller δ13Costr ranges than the marsh dominated by local fluctuations in biological activities. Based on these observations, background data of water temperatures and δ18Oprec were used to calculate monthly δ18O variations in a theoretical calcite formed in rivers in Florida assuming a direct reaction on precipitation changes. The calculated values showed a high variation coupled with low mean values during the summer wet season, while during the winter dry season the variation remains small and mean values increased. Inferred configurations were used to approximate possible calcification periods of C. ilosvayi. For a plausible calcification period, mean values and ranges of δ18Oostr had to be equal to the theoretical calcite with a slight positive offset (vital effect). The applied model suggests a seasonal calcification period of C. ilosvayi in early spring that is probably coupled to the hydrologic cycle of Florida.

Discrete seasonal hydroclimate reconstructions over northern Vietnam for the past three and a half centuries

We present a 350-year hydroclimatic year (HY) index for northern Vietnam derived from three discrete seasonal reconstructions from tree rings: an index of autumn rainfall from the earlywood widths of Chinese Douglas fir (Pseudotsuga sinensis), the first such record from this species, and two nearby published Palmer Drought Severity Index (PDSI) reconstructions from cypress (Fokienia hodginsii) tree rings for spring and summer, respectively. Autumn rainfall over the study region constitutes only around 9% of the annual total, but its variability is strongly linked to the strength of the atmospheric gradient over Asia during the transition from the boreal summer to winter monsoons. Deficit or surplus of autumn rainfall enhances or mitigates, respectively, the impact of the annual winter dry season on trees growing on porous karst hillsides. The most protracted HY drought (dry across all seasons) occurred at the turn of the twentieth century at a time of relative quiet, but a mid-to-late eighteenth century multi-year HY drought coincided with a period of great societal turmoil across mainland Southeast Asia and the Tay Son Rebellion in northern Vietnam. A mid-nineteenth century uprising accompanied by a smallpox epidemic, crop failure and famine, occurred during the worst autumn drought of the past two and a half centuries but only moderate drought in spring and summer. The “Great Vietnamese Famine” of the mid-twentieth century was dry only in autumn, with a wet spring and an average summer.

Field Study of Rice Yield Diminished by Soil Arsenic in Bangladesh.

Rice was traditionally grown only during the summer (aman) monsoon in Bangladesh but more than half is now grown during the dry winter (boro) season and requires irrigation. A previous field study conducted in a small area irrigated by a single high-arsenic well has shown that the accumulation of arsenic (As) in soil from irrigating with high-As groundwater can reduce rice yield. We investigated the effect of soil As on rice yield under a range of field conditions by exchanging the top 15 cm of soil between 13 high-As and 13 low-As plots managed by 16 different farmers, and we explore the implications for mitigation. Soil As and rice yields were measured for soil replacement plots where the soil was exchanged and adjacent control plots where the soil was not exchanged. Differences in yield (ranging from +2 to -2 t/ha) were negatively correlated to the differences in soil As (ranging from -9 to +19 mg/kg) between adjacent replacement and control plots during two boro seasons. The relationship between soil As and yield suggests a boro rice yield loss over the entire country of 1.4-4.9 million tons annually, or 7-26% of the annual boro harvest, due to the accumulation of As in soil over the past 25 years.

Impacts of Climate change on Hydropower Potential in Kaligandaki River Basin -A Case Study of Kaligandaki Gorge Hydropower Project, North of Nepal

Nepal has a considerable hydropower potentiality, however the analysis of Kaligandaki River Basin optimization of power potentiality and subsequently identified two critical impacts of climate change-GLOF’s and variability of runoff along with temperature difference are most pronounced during the dry winter season, and least during the height of the monsoon. In Himalaya region the Intergovernmental Panel on Climate Change (IPCC) has indicated that global warming is occurring relatively faster in recent decades, with the rate of temperature increase being greater in the high altitude Himalaya, then lowland parts of Nepal [1].

Phosphorus concentrations in a Florida Everglades water conservation area before and after El Niño events in the dry season

The Florida Everglades depends on both seasonal hydroperiods and low nutrient loading. This study investigated phosphorus concentrations in a 237,000-ha wetland complex in the Greater Florida Everglades known as Water Conservation Area 3A (WCA-3A). WCA-3A is south and downstream of Lake Okeechobee and most of the agricultural activity in the Everglades region, but immediately north and upstream of the Everglades National Park. The original goal of the study was to investigate if this water conservation area was serving as a phosphorus sink during a 9-month period (October 2015 to June 2016) that normally would have bracketed the dry winter season of south Florida. The beginning of 2016 brought several unexpected polar fronts with high rainfall, an unusual weather pattern in subtropical Florida later confirmed to have been caused by an El Niño condition in the Pacific Ocean. Samples taken at the beginning of the dry season (October through December 2015 during pre-El Niño conditions) showed low phosphorus concentrations. In April and June 2016 during post-El Niño conditions, monthly average total phosphorus concentrations averaged 7.1–7.2ppb total phosphorus in inflow region of WCA-3A, significantly higher (P=0.030 and 0.045) than 3.0 and to 2.6ppb in the wetland’s outflow region. The wetland was found to be a sink of phosphorus with a 47% decrease in total phosphorus from north to south during this post- El Niño time. If future additional wetlands and water quality strategies are not in place to mitigate fluxes of phosphorus during future climate variations such as this El Niño condition, this wetland complex may take on an even greater role of protecting the water quality of the downstream Everglades National Park.

Analyzing cloud base at local and regional scales to understand tropical montane cloud forest vulnerability to climate change

Abstract. The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming or deforestation. To establish a baseline for quantifying future changes in cloud base, we installed a ceilometer at 100 m altitude in the forest upwind of the TMCF that occupies an altitude range from ∼ 600 m to the peaks at 1100 m in the Luquillo Mountains of eastern Puerto Rico. Airport Automated Surface Observing System (ASOS) ceilometer data, radiosonde data, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite data were obtained to investigate seasonal cloud base dynamics, altitude of the trade-wind inversion (TWI), and typical cloud thickness for the surrounding Caribbean region. Cloud base is rarely quantified near mountains, so these results represent a first look at seasonal and diurnal cloud base dynamics for the TMCF. From May 2013 to August 2016, cloud base was lowest during the midsummer dry season, and cloud bases were lower than the mountaintops as often in the winter dry season as in the wet seasons. The lowest cloud bases most frequently occurred at higher elevation than 600 m, from 740 to 964 m. The Luquillo forest low cloud base altitudes were higher than six other sites in the Caribbean by ∼ 200–600 m, highlighting the importance of site selection to measure topographic influence on cloud height. Proximity to the oceanic cloud system where shallow cumulus clouds are seasonally invariant in altitude and cover, along with local trade-wind orographic lifting and cloud formation, may explain the dry season low clouds. The results indicate that climate change threats to low-elevation TMCFs are not limited to the dry season; changes in synoptic-scale weather patterns that increase frequency of drought periods during the wet seasons (periods of higher cloud base) may also impact ecosystem health.

Feeding Response of Tree Fodder Bhimal (Grewia optiva) on Growth Performance of Castrated Male Goats

Bhimal (Grewia optiva) is a fodder tree mostly found in mid hills of mid and far western region of Nepal. Bhimal could constitutes one of the main livestock green fodders, especially for goats when fresh green fodder become limited during the winter dry season. However, the feeding value of Bhimal leaves on growth performance of castrated goats probably has not been evaluated so far. Therefore, an experiment was conducted to evaluate the effect of Bhimal leaves feeding on growth performance of castrated male goats for 90 days. Altogether 16 growing castrated male goats of same breed, age and body weight were selected and equally divided into four treatments T1, T2, T3 and T4 with four replications by using Completely Randomized Design (CRD). Four types of experimental diets were prepared having various levels (0 to 100%) of Bhimal leaves as fodder. Experimental animals of Treatment 1 were fed with seasonal fodder + 100 g concentrate mixture, Treatment 2 with 100% Bhimal fodder + 100 g concentrate mixture, Treatment 3with 75% Bhimal fodder + 25% seasonal fodder + 100 g concentrate mixture, while Treatment 4 with 50% Bhimal fodder + 50% season fodder + 100 g concentrate mixture. All diets were fed ad-lib and experimental animals had free access to drinking water. The diets offered and refusal was measured daily and weight change was observed fortnightly. The result showed that fodder intake (g/d/animal) and total dry matter intake (TDMI g/kg live weight) of goats differed significantly (P&lt;0.01), but concentrate intake was not differed significantly (P&lt;0.01) among treatments. The highest dry matter intake per animal /day was in Treatment 2 (52.75 g/kg live weight) followed by Treatment 4, Treatment 3 and Treatment 1 (51.7, 48.56 and 32.69 g/kg live weight, respectively).The average daily gain in body weight was observed highest in Treatment 2 (66.66 g/d) followed by Treatment 3 (31.66 g/d) and Treatment 4 (30.83 g). The growth rate was significantly (P&lt;0.01) different among diet groups (P&lt;0.05, P&lt;0.01 and P&lt;0.01 for 60, 75 and 90 days, respectively). In case of the feed conversion ratio, Treatment 2 had best ratio (8.79:1) than Treatment 1 (14.21:1), T3 (17.03:1) and Treatment 4 (18.59:1). The present response study showed that body weight in castrated male goats can be increased significantly (P&lt;0.05) implying that in winter season when other green forages are poorly available goat farming can be supported by Bhimal fodder tree.Journal of Nepal Agricultural Research Council Vol.3 2017: 1-11

Spatiotemporal variations in precipitation across the Chinese Mongolian plateau over the past half century

Precipitation, as affected by climate change, controls the growth of steppe grasses and grassland degradation/desertification in semiarid/arid regions, including the Chinese Mongolian plateau. This study examined the spatial variability and temporal trends in precipitation across the plateau in terms of four indexes: total precipitation (P), number of rainy days (Wd), number of precipitation events (N), and average precipitation intensity (Imean). Although seldom published in the literature, this information is vital for efforts to develop adaptive measures to sustain this vulnerable pasture economy. Seven hundred time series were formulated by preprocessing the data on daily precipitation over the period 1960 to 2012 at 25 weather stations scattered across the plateau. The results indicated that although the plateau was becoming drier overall, the intensity of storm events increased markedly, as indicated by decreasing trends for P, Wd and N but an increasing trend for Imean. On average, P decreased by 0.65mmyr−1 over the study period, while Imean increased by 0.2mmd−1yr−1. Across the plateau, the western part was becoming wetter, while the central-eastern part was becoming drier. This spatial discrepancy in the precipitation trends was particularly obvious in the winter dry season, with Imean tending to increase more rapidly in the central-eastern than western part, especially in the spring dry season. It is expected that these trends will continue, thus further challenging the already vulnerable eco-environment of the plateau.

Productivity ofMoringa oleiferaaugmented with intercropped tropical legumes

In Limpopo Province of South Africa, a trial was conducted over four seasons (one each year, from September 2011 to May 2015) to assess the productivity of Moringa oleifera 'PKM 1' grown with tropical legumes. Season 1 was devoted to the establishment of 120-m long rows of moringa trees, with seeds spaced 1 (in-row) × 3 (between-row) m. Except for a 1-m wide weed-free band at the base of each moringa row, the alleys were kept in native grasses to minimize weeding. Arranged in a randomized complete block design with five replications, treatments consisted of a no-legume control and four legumes [cowpea (Vigna unguiculata 'ITD98'), jack bean (Canivalia ensiformis), lablab (Lablab purpureus 'Highworth') and pigeon pea (Cajanus cajan 'Kranti')] sown below the moringa trees during seasons 2 and 4. During season 3, the 1-m wide weed-free strip beneath the moringa trees was sown to okra (Abelmoschus esculentus) and kale (Brassica oleracea). The moringa trees were heavily mulched with straw over the winter dry seasons, and pruned to a height of 1 m at each of two leaf harvests per season (2-4). Total season-2 (223-279 kg ha-1) and season-3 (314-466 kg ha-1) moringa powder yields were unaffected by season-2 legumes. Season-4 moringa productivity, however, was lower (P<0.0001) with (191-340 kg ha-1) than without (473 kg ha-1) legumes, likely due to weather conditions favoring legume competition with moringa. Legumes performed better under moringa than the vegetables. Results indicated that, where short-duration freezes occur, 1 ha of this system can provide - over the course of a year - a daily supply of 5 g of moringa powder for each of 120-153 people by the second season. Additionally, legumes were shown to contribute as much as 5 (jack bean) to 6 (lablab) t ha-1 of dry, above-ground biomass and 525 kg ha-1 (lablab) of dry beans. Steps such as pruning moringa above 1 m are suggested to minimize adverse effects of legume competitiveness with moringa.

Holistic performance appraisal of a photovoltaic system

During this research, performance of a 2.45 kWp PV system was evaluated over a period of 5 years. International electrotechnical committee (IEC) standard, IEC 61724: 1998 and a robust mathematical model were used as a guide for the purpose. Performance of the system was closely monitored during the dry winter season. Annual production decreased from 3463.8 kWh to 3370.9 kWh and the capacity utilisation factor decreased from 16.14% to 15.71% over the period. Monthly production was stochastic, but the average monthly production curve followed the same trend as incident global horizontal radiation with low production during dry winter months. Performance ratio was above 90% at the beginning of dry winter month, it then decreased to less than 70% after three months. A mathematical model based on five parameter model and one diode equation was then used to extract essential cell parameters and simulate performance of the system. Statistical indices were computed to assess performance of the model against measurement data. Hence the quality factor of the PV system was computed and was found to be between 60% and 100% with an average of 87% in the dry winter month.

Seasonal Pattern In the High-Elevation Fluvial Travertine From the Jiuzhaigou National Nature Reserve, Sichuan, Southwestern China

Abstract: The Jiuzhaigou National Nature Reserve on the Tibetan Plateau (Sichuan, southwestern China) is characterized by the deposition of fluvial travertine in a spectacular array of shoals, waterfalls, pool dams, and multicolored lakes. This is possibly the highest vegetated travertine setting of the world, from 2200 to 2900 m above sea level, an environment sensitive to minimal changes in temperature and precipitation regime. The evolution of the system is driven by two seasonal monsoon climate patterns with a wet spring–summer travertine deposition and then a dry fall–winter characterized by no precipitation or erosion. Spring and phreatic–vadose deposits transition from laminated columnar calcite to clotted micrite encrustation, possibly correlated with a mid-Holocene peak in precipitation and high lake levels in the northeastern Tibetan area connected to glacial advance. The most peculiar features are the fluvial shoals, a rather uncommon travertine surface consisting of two main superimposed facies of alternating weak- and strong-turbulence water flow. The low-turbulence facies consists of clotted micrite encrustation of mosses and cyanobacteria filaments, and platy calcite crystals covering algal filaments. The high-water-turbulence facies show seasonal alternation of diatom-rich bundles of Phormidium sp. (late spring) with algal Oocardium stratum levels (summer–fall). Upslope and downslope of the shoals, the precipitation of calcium carbonate results in the formation of prograding waterfalls and dam–pool systems that encrust macrophytes with microspar and clotted micrite. Encrusted chironomids larvae tubes are present in the waterfall walls up to an elevation of 2860 m, possibly the highest ever recorded. Early diagenetic processes such as dissolution of diatom frustules take place over the span of several years, a slower phenomenon compared to other travertine occurrences. In this high-elevation extreme setting, travertine sand and gravel bar deposits are produced by the exposure to severe weathering of a section of the valley that is bypassed through an underground karst system during the winter dry season. High-elevation travertine probably has a low preservation potential, but it appears to be more sensitive to climate changes than other depositional settings, especially in the Himalayan–Tibetan area, where the extent of the Quaternary glacial advances and retreats is still a matter of debate.

The response of some physiological traits of chickpea (Cicer arietinum L.)to biochar and phosphorus fertilizer application

This study assessed the response of photosynthesis, chlorophyll content (CC), stomatal conductance (SC) and intercepted radiation (IR) of chickpea to biochar (0, 5 10 and 20 t ha-1) and phosphorus (P) fertilizer (0 and 90 kg ha-1) rates in Thohoyandou, South Africa in 2013/2014 summer and winter seasons. Photosynthesis, CC, SC and IR were determined at vegetative and reproductive stages. Biochar increased SC and CC by 22 - 49% and 57 – 126%, respectively. P increased CC by up to 9% in the winter sowing. IR increased with P and biochar application in both sowings. Biochar increased plant height only at 70 days after emergence and P increased plant height at all plant growth stages. Biochar and phosphorus did not affect photosynthesis in either season. Therefore the use of biochar and inorganic phosphorus fertilizer may be beneficial in chickpea cropping systems characterised by poor soils and dry winter seasons.

Coral reef origins of atmospheric dimethylsulfide at Heron Island, southern Great Barrier Reef, Australia

Abstract. Atmospheric dimethylsulfide (DMSa), continually derived from the world's oceans, is a feed gas for the tropospheric production of new sulfate particles, leading to cloud condensation nuclei that influence the formation and properties of marine clouds and ultimately the Earth's radiation budget. Previous studies on the Great Barrier Reef (GBR), Australia, have indicated coral reefs are significant sessile sources of DMSa capable of enhancing the tropospheric DMSa burden mainly derived from phytoplankton in the surface ocean; however, specific environmental evidence of coral reef DMS emissions and their characteristics is lacking. By using on-site automated continuous analysis of DMSa and meteorological parameters at Heron Island in the southern GBR, we show that the coral reef was the source of occasional spikes of DMSa identified above the oceanic DMSa background signal. In most instances, these DMSa spikes were detected at low tide under low wind speeds, indicating they originated from the lagoonal platform reef surrounding the island, although evidence of longer-range transport of DMSa from a 70 km stretch of coral reefs in the southern GBR was also observed. The most intense DMSa spike occurred in the winter dry season at low tide when convective precipitation fell onto the aerially exposed platform reef. This co-occurrence of events appeared to biologically shock the coral resulting in a seasonally aberrant extreme DMSa spike concentration of 45.9 nmol m−3 (1122 ppt). Seasonal DMS emission fluxes for the 2012 wet season and 2013 dry season campaigns at Heron Island were 5.0 and 1.4 µmol m−2 day−1, respectively, of which the coral reef was estimated to contribute 4 % during the wet season and 14 % during the dry season to the dominant oceanic flux.

Geosystem pollution by radioactive strontium near a regional radioactive waste repository

Radioecological studies were carried out in a territory polluted by 90Sr delivered by groundwater after leakage from a tank in a near-surface radioactive waste repository. The layer-by-layer vertical distribution of 90Sr in soil down to 3 m is analyzed. The area of radioactive pollution above the minimal significant activity level (1 Bq/kg by NRB-99/2009) in the examined soil layers decrease with depth as follows: 1808 m2 at 0–5 cm, 302 m2 at 5–10 cm, and 181 m2 at 10–15 cm. The accumulation of 90Sr takes place at a natural sorption geochemical barrier—a swampy area in a near-terrace depression. The radiation dozes were calculated for terrestrial mollusk of Bradybaena fruticum, accumulating strontium in its shell; the doses are in excess of the screening value of 2.4 μGr/day in 41% of the territory. This is higher than the acceptable risk level (5%) for this mollusk population. An excess of the intervention level for 90Sr was recorded in both subsurface and surface waters in this geosystem during winter and summer dry seasons and autumn showers.