Peak In May Research Articles

Spatial and temporal variability of organic C and N concentrations and export from 30 boreal rivers induced by land use and climate

Climate change scenarios for northern boreal regions indicate that there will be increasing temperature and precipitation, and the changes are expected to be larger in winter than in summer. These precipitation and discharge patterns, coupled with shorter ice cover/soil frost periods in the future would be expected to contribute significantly to changing flow paths of organic matter over a range of land use patterns. In order to study the impact of climate change on the seasonality of organic matter export we compared total organic carbon (TOC) and total organic nitrogen (TON) concentrations and export, during different seasons and climatically different years, over 12years for 30 Finnish rivers separated into forest, agriculture and peat dominated catchments. The mean monthly TOC concentrations were highest during autumn and there was also a peak in May during the highest flow period. The mean monthly concentrations of TON were lowest during winter, increased in spring and remaining high throughout summer and autumn. The TOC/TON ratios were lowest during summer and highest during winter, and in all seasons the ratios were lowest in catchments with a high proportion of agricultural land and highest in peat-dominated catchments. The seasonality of TOC and TON exports reflected geographical location, hydrology and land use patterns. Most of the TOC and TON were transported during the high flow following the spring snowmelt and during rainfall in autumn. In all catchments the relative importance of the spring snowmelt decreased in wet and warm years. However, in peat-dominated catchments the proportion of spring period was over 30% of the annual export even in these wet and warm years, while in other catchments the proportion was about 20%. This might be linked to the northern location of the peat-dominated catchments and the permanent snow cover and spring snowmelt, even in warm years.

Clinical features of children infected with influenza virus A in year 2009 in Wuhan area

Objective To explore the clinical and pandemic features and respiratory pathogen co-infection characteristics of children infected with influenza virus A(Flu A)in year 2009. Methods A retrospective study of hospitalized children with flu-like clinical symptoms in 2009 was conducted.The peripheral blood serum was analyzed to detect common respiratory agents, including Flu A, respiratory syncytial virus, adenovirus, influenza virus B, parainfluenza virus 1, 2 and 3, chlamydia pneumonia and mycoplasma pneumonia, klebsiella pneumonia(KP), haemophilus in-fluenza and legionella pneumophila by using indirect immunofluorescence test for the antibody detection (IgM). And a standard medical history was recorded, including epidemiological data, clinical manifestation, and the length of hospital stay, white blood count and chest X-ray elsewhere.All specimens were collected in Department of Pediatrics, Zhongnan Hospital of Wuhan University, from Jan.2009 to Dec.2009. Results Flu A was detected in 234 of the 599 (39.1%, 234/599 cases) flu-like children.The mean age was 48.8 months (range from 3 to 167 months). The detection rate in less than 1-year-old group (11.1%, 18/162 cases) was obviously lower than that of the older groups(P<0.001). Especially for the group< 6 months, there was only 1 infant (1.43%, 1/70 cases) with Flu A positive.Compared with Flu A negative group, the main clinical features of children with Flu A positive group were fever(78.2%, 183/234 cases, P=0.013) and cough(76.5%, 179/234 cases, P=0.04), however asthma (14.1%, 33/234 cases, P=0.003) and diarrhea (6.0%, 14/234 cases, P=0.001) cases were less.The detection rates of Flu A reached a peak of 57.0% in November and December, and a secondary peak of 45.0% in May and June.Flu A infection children less than 1 year old were simple in etiology.The children were older, the etiology was more complex.The primary coinfection pathogen was KP (53.8%, 126/234 cases) and Flu B(48.3%, 113/234 cases). Compared Flu A coinfection with or without KP, there was no difference between these 2 groups in the clinical features. Conclusions Influenza A is the main pathogen of hospitalized children with flu-like symptoms in 2009.Children over 1 year old age were the major infection groups of Flu A. The detection rates of Flu A reached peaks in May to June and November to December.Flu A positive children were prone to KP coinfection. Key words: Influenza A; Child; Respiratory tract infection; Coinfection

Representativeness and seasonality of major ion records derived from NEEM firn cores

Abstract. The seasonal and annual representativeness of ionic aerosol proxies (among others, calcium, sodium, ammonium and nitrate) in various firn cores in the vicinity of the NEEM drill site in northwest Greenland have been assessed. Seasonal representativeness is very high as one core explains more than 60% of the variability within the area. The inter-annual representativeness, however, can be substantially lower (depending on the species) making replicate coring indispensable to derive the atmospheric variability of aerosol species. A single core at the NEEM site records only 30% of the inter-annual atmospheric variability in some species, while five replicate cores are already needed to cover approximately 70% of the inter-annual atmospheric variability in all species. The spatial representativeness is very high within 60 cm, rapidly decorrelates within 10 m but does not diminish further within 3 km. We attribute this to wind reworking of the snow pack leading to sastrugi formation. Due to the high resolution and seasonal representativeness of the records we can derive accurate seasonalities of the measured species for modern (AD 1990–2010) times as well as for pre-industrial (AD 1623–1750) times. Sodium and calcium show similar seasonality (peaking in February and March respectively) for modern and pre-industrial times, whereas ammonium and nitrate are influenced by anthropogenic activities. Nitrate and ammonium both peak in May during modern times, whereas during pre-industrial times ammonium peaked during July–August and nitrate during June–July.

Phytoplankton dynamics and water quality of Prashar Lake, Himachal Pradesh, India

Abstract Prashar Lake, an unexplored, high-altitude, shallow, and cold water body located in Himachal Pradesh (India) was studied through monthly surveys in two consecutive years (March 2008 to February 2010). The seasonal variations in chlorophyll a , abundance, and species composition of plankton in relation to hydrography were studied. A total of 67 species belonging to eight groups of phytoplankton were identified. Among 67 phytoplankton species, 19 species exhibited perennial habit. Both plankton and chlorophyll a showed bimodal pattern of fluctuation with peaks in May and September. Annual mean concentrations of chlorophyll a (mg L − 1 ) were recorded as 4.87 in 2008–09, and 4.03 in 2009–10. Palmer pollution index indicated absence of all the 20 pollution tolerant algal species. Pearson correlation revealed a significant relationship between physicochemical parameters and different algal groups. Important physicochemical parameters responsible for distribution of phytoplankton have been studied taking into account the portability of water for irrigation and drinking purposes as per permissible limits of WHO, ICMR, and ISI standards. The values of water quality index were 14.42 during 2008–09 and 16.51 during 2009–10. Based on water quality standards given by Central Pollution Control Board, the water quality at Prashar Lake was between “A and B”. Carlson’s trophic status classified Prashar Lake as oligotrophic with TSI values 17.085 (2008–09) and 14.57 (2009–10). The phytoplankton assemblage, as well as water quality data, suggest that water at Prashar Lake is unpolluted and could be used for various human purposes after disinfection.

Characteristics and changes of streamflow on the Tibetan Plateau: A review

• Basins on the Tibetan Plateau have their unique environmental settings. • Rivers are affected by their settings, contributors, climate systems and human activity. • Outstanding research topics in hydrology of the Tibetan Plateau are identified. The Tibetan Plateau (TP). The TP exerts great influence on regional and global climate through thermal and mechanical forcings. The TP is also the headwater of large Asian rivers that provide water for billions of people and numerous ecosystems. Understanding the characteristics and changes of streamflow on the TP will help manage water resources under changing environment. Three categories of rivers (the Pacific Ocean, the Indian Ocean, and the interior) on the TP were examined for their seasonal and long term change patterns. Outstanding research issues were also identified. Streamflow follows the monthly patterns of precipitation and temperature in that all peak in May–September. Streamflow changes are affected by climate change and human activities depending on the basins. Streamflow is precipitation dominated in the northern, eastern and southeastern basins. In the central and western basin either melt water or groundwater, or both contributes significantly to streamflow. Human activities have altered streamflow in the lower reaches of the eastern, northern and western basins. Long-term trends in streamflow vary with basins. Outstanding research issues include: (1) What are the linkages between streamflow and climate systems? (2) What are the basin-wide hydrological processes? And (3) What are the cryospheric change impacts on hydrological processes and water balance?

Seasonal variation of planktonic chrysophytes with special focus on Dinobryon.

The diversity of chrysophytes is often underestimated in morphological surveys because of the limited amount of detectable characters under the light microscope. Addressing biodiversity issues solely based on morphological characters is further problematic since molecular analyses revealed a huge genetic diversity within morphotypes, even showing polyphyly in some morphological defined species. In order to address the seasonal variations of chrysophytes, 10 samples were collected in 2007 from the oligotrophic lake Fuschlsee (Salzkammergut, Austria). By using Dinobryon as a case study, we compared different gene phylogenies of single cells of the 18S, ITS (including ITS1, 5.8S, partial ITS2) and the mitochondrial marker COI. No clear molecular phylogenetic separation between morphological identified cells of D. divergens and D. bavaricum could be accomplished based on the 18S rDNA sequences. ITS and COI sequence data revealed a higher genetic diversity then the 18S, with several independent lineages consisting of D. divergens cells. We further encountered divergent phylogenies by comparing 18S/ITS sequence data with COI data within D. pediforme, D. sociale and D. bavaricum lineages. By combining the results of the single cell approach with seasonal data based on 454 pyrosequencing, we addressed the question in how far one morphological species may dominate in the water column over the course of a single year. The results of the 454 pyrosequencing revealed that the D.divergens/D. bavaricum lineage shows the highest abundance from all Chrysophyceae/Synurophyceae and strong seasonal variations with peaks in May and October.

Comprehensive Pattern of Deep Convective Systems over the Tibetan Plateau–South Asian Monsoon Region Based on TRMM Data

Abstract Diurnal and seasonal variation, intensity, and structure of deep convective systems (DCSs; with 20-dBZ echo tops exceeding 14 km) over the Tibetan Plateau–South Asian monsoon region from the Tibetan Plateau (TP) to the ocean are investigated using 14 yr of Tropical Rainfall Measuring Mission (TRMM) data. Four unique regions characterized by different orography are selected for comparison, including the TP, the southern Himalayan front (SHF), the South Asian subcontinent (SAS), and the ocean. DCSs and intense DCSs (IDCSs; with 40-dBZ echo tops exceeding 10 km) occur more frequently over the continent than over the ocean. About 23% of total DCSs develop into IDCSs in the SHF, followed by the TP (21%) and the SAS (15%), with the least over the ocean (2%). The average 20-dBZ echo-top height of IDCSs exceeds 16 km and 9% of them even exceed 18 km. DCSs and IDCSs are the most frequent over the SHF, especially in the westernmost SHF, where the intensity—in terms of strong radar echo-top (viz., 40 dBZ) height, ice-particle content, and lightning flash rate—is the strongest. DCSs over the TP are relatively weak in convective intensity and small in size but occur frequently. Oceanic DCSs possess the tallest cloud top (which mainly reflects small ice particles) and the largest size, but their convective intensity is markedly weaker. DCSs and IDCSs show a similar diurnal variation, mainly occurring in the afternoon with a peak at 1600 local time over land. Although most of both DCSs and IDCSs occur between April and October, DCSs have a peak in August, whereas IDCSs have a peak in May.

A Cross-sectional Study on Scorpionism in Masjed Soleyman County, Southwestern Iran

In Iran, scorpions are the important causative agents of toxication and deaths among venomous animals. Understanding about their epidemiologic characteristics could lead to the utilization of suitable preventive methods. Therefore, with the aim of contributing to basic knowledge on scorpion sting as acommon health problem, epidemiological features of scorpionism have been investigated in Masjed Soleyman County, Khuzestan Province, South west of Iran, over a two year period (2006-2007). This is a descriptive study which was done in Masjed Soleyman County. All the patients which were referred to Masjed Soleyman health services centers were assayed. Some data about epidemiologic and demography parameters were collected and recorded bya physician in a questionnaire. Then, these information were analyzed in SPSS by using descriptive statistics. During the period of study, 11169 cases of scorpion stings had been reported to Masjed Soleyman health services centers. Of total 11169 studied patients 54.4 were male. Feet (39.3) and hands (37) were the most common body part affected. The highest incidence of envenoming occurred during the first three months of the year, with the highest peak in May (14.4). The most cases occurred during spring (36.8) and summer (33.8) seasons. Our experience indicates that scorpionism appeared with more frequency in the urban areas (79.6). In all, 20.4 of individuals were from rural regions. Scorpion stings have been mostly seen in individuals of the age of 15 and over (77.4). In this study, 14 of the stings were in children aged up to 10 years while those aged 44 and over constituted only 18.6 of the reported accidents. About 10.5 and 50.8 of envenomed cases were due to black and yellow scorpions, respectively. A good control plan for this region should be observed all year long, particularly ago or during the greater risk periods. As regards scorpion envenoming is of a seasonal feature in Masjed Soleyman County, it is possible to forespeak the greater incidence periods and take the relevant measures. © 2014 Academic Journals Inc.

Annual population dynamics of mango fruit flies (Diptera: Tephritidae) in West Africa: socio-economic aspects, host phenology and implications for management

Introduction. Losses in West African commercial mango orchards due to fruit fly infestations have exceeded 50% by the middle of the crop season since 2005, resulting in considerable income loss for the growers. Materials and methods. In 2009, weekly monitoring of adult fruit fly species of economic significance was carried out in eight West African countries at 12 sites across five agro-ecological zones: (i) Humid Forest, (ii) Guinean savanna, (iii) Southern Sudan, (iv) Northern Sudan, and (v) Sahelian. Trapping was performed using methyl eugenol and terpinyl acetate in 288 Tephri-traps, targeting Bactrocera invadens and Ceratitis cosyra. Results. The data showed that B. invadens was present throughout the year in the Forest zone, abundant for 7 months, with a peak in May at the end of the mango season, C. cosyra being totally absent. In the Guinean savanna zone, B. invadens was abundant for 6-7 months, with a peak at the beginning of June coinciding with the season, with a few C. cosyra. In the Southern Sudan zone, B. invadens was abundant for 6 months, with a peak in mid-June during the season, C. cosyra peaking in April. In the Northern Sudan zone, B. invadens was abundant for 5 months, with a peak at the end of June at the end of the season, C. cosyra peaking in May. In the Sahelian zone, B. invadens was abundant for 4 months, peaking in August during the season, C. cosyra peaking just before. These preliminary results showed that the exotic species, B. invadens, was present at high levels [mean peak of 378 flies per trap per day (FTD)] in all agro-ecological zones, while the native species, C. cosyra, preferred the drier zones of West Africa, with lower population levels (mean peak of 77 FTD). Conclusion. Detection trapping of male flies with parapheromones is a useful indicator of field population levels and could be used to deploy control measures (IPM package) in a timely manner when the Economic Injury Level is reached. Control strategies for these quarantine mango fruit fly species are discussed with respect to agro-ecological zones and the phenological stages of the mango tree.

Investigating the coupling between phytoplankton biomass, aerosol optical depth and sea-ice cover in the Greenland Sea

We investigate the relationship between satellite-derived time series for microalgal biomass, measured using remotely sensed chlorophyll-a (CHL: mgm−3), aerosol optical depth (AOD) and sea ice cover (ICE) in the Greenland Sea (10° W–10° E, 65–80° N) over the decadal period 2003–2012. Zonal averages for all variables were computed in 5-degree latitude bands. Unlike other regions of the Arctic Ocean, the marginal ice zone in the Greenland Sea is confined to north of 75° N. The CHL time series is characterized by high interannual variability, especially in the northern marginal sea ice zone (MIZ) where variability in sea ice extent is a likely factor. The ten-year climatology shows that CHL increases from March, reaching a seasonal peak in May in the southern sector and in June in the northern sectors. The climatological peak of AOD is achieved in April in all latitude bands, about a month before the peak in CHL. This suggests that the Arctic aerosol burden is strongly affected by continental sources in early spring.Interestingly, a summer increase in AOD (which succeeds the CHL maximum) is seen in some years. Sea ice extent in early spring is less than 40% in the northern sector in all years. There is considerable interannual variability in both the onset of melt and the extent of sea ice loss during summer, with the minimum summer sea ice extent decreasing to almost zero in five of the years. Cross-correlation analyses of the three times series identify a statistically significant relation between CHL and AOD in six of the years in the southern sector, but no correlation between CHL and ICE was found in the northern sector. There is, however, a significant correlation between AOD and ICE time series in the northern sector in four years. High AOD values registered in early spring are most likely of anthropogenic origin, however, peaks later in summer coincident with the phytoplankton bloom and high emissions of biogenic aerosol precursors such as dimethylsulfide and other primary aerosols of marine origin, suggest the summer atmospheric aerosol burden is likely influenced by biogenic emissions.

Atmospheric mercury speciation and mercury in snow over time at Alert, Canada

Abstract. Ten years of atmospheric mercury speciation data and 14 years of mercury in snow data from Alert, Nunavut, Canada, are examined. The speciation data, collected from 2002 to 2011, includes gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM). During the winter-spring period of atmospheric mercury depletion events (AMDEs), when GEM is close to being completely depleted from the air, the concentration of both PHg and RGM rise significantly. During this period, the median concentrations for PHg is 28.2 pgm−3 and RGM is 23.9 pgm−3, from March to June, in comparison to the annual median concentrations of 11.3 and 3.2 pgm−3 for PHg and RGM, respectively. In each of the ten years of sampling, the concentration of PHg increases steadily from January through March and is higher than the concentration of RGM. This pattern begins to change in April when the levels of PHg peak and RGM begin to increase. In May, the high PHg and low RGM concentration regime observed in the early spring undergoes a transition to a regime with higher RGM and much lower PHg concentrations. The higher RGM concentration continues into June. The transition is driven by the atmospheric conditions of air temperature and particle availability. Firstly, a high ratio of the concentrations of PHg to RGM is reported at low temperatures which suggests that oxidized gaseous mercury partitions to available particles to form PHg. Prior to the transition, the median air temperature is −24.8 °C and after the transition the median air temperature is −5.8 °C. Secondly, the high PHg concentrations occur in the spring when high particle concentrations are present. The high particle concentrations are principally due to Arctic haze and sea salts. In the snow, the concentrations of mercury peak in May for all years. Springtime deposition of total mercury to the snow at Alert peaks in May when atmospheric conditions favour higher levels of RGM. Therefore, the conditions in the atmosphere directly impact when the highest amount of mercury will be deposited to the snow during the Arctic spring.

Enterovirus infection in children attending two outpatient clinics in Zhejiang province, China

Enteroviruses are responsible for hand, foot, and mouth disease, and have caused many deaths in China during recent years. But the natural history of enterovirus infection in children, especially asymptomatic children, is not yet clear. From April 2011 to May 2012, 505 stool and throat swab samples of children attending outpatients clinics in two hospitals were collected weekly to test for Enterovirus 71, Coxsackievirus A16, and other enterovirus nucleic acids by real-time RT-PCR. Two hundred sixty-four patients were enterovirus positive, the positive rate was 52.3%, 27.5% (22/80) in children without a rash and 56.9% (242/425) in children with a rash. Coxsackievirus A16 positive rate of male (24%, 61/254) was higher than that of female (15.2%, 26/171) (χ(2) = 4.87, P = 0.027). The highest positive rate of enterovirus infection was 63.5% in the 2-year-old age group. Comparing children with and without a rash, within the same age groups, no statistical difference was found (P > 0.05). The seasonal distribution of Enterovirus 71 had only one peak in May, but Coxsackievirus A16 had two peaks in April and October. In patients with a rash, the frequency of Enterovirus 71 was relatively high before July, and then that of Coxsackievirus A16 increased gradually. In the case of Enterovirus 71 and Coxsackievirus A16, stool specimens had a higher positive rate than throat swab specimens' (χ(2) = 3.88, P = 0.05; χ(2) = 15.13, P < 0.001). Enterovirus infection was more frequent in males 2-3 year-old children, with the implicated virus varying by season. Targeted prevention and control measures should be carried out.

Phenology of a tropical dry deciduous forest of Bhadra wildlife sanctuary, southern India

IntroductionThis paper describes the leafing, flowering and fruiting phenology of canopy trees in the dry deciduous forest of Bhadra wildlife sanctuary from June 2004 to May 2006.MethodAll the woody canopy individuals (> 20 cm girth at breast height) were identified and tagged with a unique number along a transect of approximately 2 Km comprising 157 individuals of 22 species. Observations were made at monthly intervals from June 2004 to May 2006 for leafing, flowering and fruiting phenophases.ResultLeaf fall starts in September, with a peak in December and January. Leaf initiation begins in February, with a peak in April before the monsoon. Leaf expansion starts in February from pre-monsoon with a peak in May and July during the monsoon. Leaf senescence begins in September to November and peaks in January to March. Flower bud initiates in January with a peak in April and May, and pollination begins in April with a peak in May and July before the monsoon to onset of monsoon. Fruit bud initiates in May with a peak in September and October. Unripened fruit was observed in May with a peak in September and November. Fruit fall begins in November with a peak in March.ConclusionOur results show that leafing and flowering activities occur in the summer or pre-monsoon. Fruiting patterns occur during the monsoon to post - monsoon season. Seasonality among various phenophases indicates that leaf senescence flower initiation and fruit fall have strong seasonality.

Age, Growth, and Mortality of Yellowmouth Grouper from the Southeastern United States

AbstractThe Yellowmouth Grouper Mycteroperca interstitialis is a member of the snapper–grouper complex that is managed by the South Atlantic Fishery Management Council. There is little published life history information—specifically age–growth parameters—for use in assessing the resource. We sampled Yellowmouth Grouper from the fisheries along the southeastern U.S. coast from 1980 to 2012 (n = 391), determining ages by counting opaque zones on sectioned sagittal otoliths. Opaque zones were annular, forming in May–August with a peak in May and June. Yellowmouth Grouper age ranged from 3 to 31 years, and the largest fish was 859 mm FL. Body size relationships were as follows: whole weight W (g) = (8.89×10−6)(FL, mm)3.07 (n = 339; r2 = 0.96); W (g) = (1.13×10−5)(TL, mm)3.01 (n = 165; r2 = 0.96); and TL (mm) = 10.09 + [1.05×(FL, mm)] (n = 162; r2 = 0.98). The von Bertalanffy growth equation for Yellowmouth Grouper was Lt (length at age t) = 755[1 − e−0.14(t + 1.42)] when the model included an adjustment for minimum size limits and was Lt = 772[1 − e−0.11(t + 4.18)] when the model was not adjusted. Natural mortality (M) estimated by Hewitt and Hoenig's (2005) longevity‐based method was 0.14. Age‐specific estimates of M were obtained with the Charnov et al. (2013) method. The selection of growth model (size limit adjusted versus unadjusted) had a marked effect on M for the earliest ages: M was 1.22 versus 0.43 for age 0; 0.72 versus 0.35 for age 1; 0.51 versus 0.29 for age 2; 0.40 versus 0.26 for age 3; 0.33 versus 0.23 for age 4; and 0.29 versus 0.21 for age 5. We believe that these life history parameter estimates are accurate for Yellowmouth Grouper in southeastern U.S. fisheries.Received June 6, 2013; accepted November 12, 2013

Synergistic Approach for the Aerosol Monitoring and Identification of Types over Indo-Gangetic Basin in Pre-Monsoon Season

Aerosol optical and microphysical properties were studied at two major industrial cities (Delhi and Kanpur) of the Indo-Gangetic Basin (IGB) during three (2007–2009) consecutive pre-monsoon (PrM: March–May) seasons, using synergetic analyses of CALIOP, MODIS, AERONET and PARASOL observations. CALIOP-derived aerosol properties show vertically elevated aerosol profiles (up to 4 km altitude), majorly consisting of dust particles during all three PrM seasons with maximum loading in May, 2008. The above inference is well corroborated with columnar aerosol properties from MODIS and AERONET observations. The results also show higher aerosol optical depth (AOD) over Delhi as compared to Kanpur. The high aerosol loading found during the late PrM season at both locations can be attributed to the fact that dust/burning activities are at their peak in May during the PrM season over the IGB. The analyses of optical and microphysical parameters coupled with backward trajectory analyses indicate the presence of three different aerosol types (Type I, Type II and Type III) over both cities during PrM 2009. Type I is characterized as dust-dominated aerosols coming via long-range transportation from major dust sources (desert of Sahara, Iran, Afghanistan and western India), whereas a mixture of absorbing aerosols and dust coming from the Arabian Peninsula and the Thar Desert is characterized as Type II aerosols. The presence of highly absorbing, fine mode dominated Type III aerosols are categorized as urban-industrial/biomass burning aerosols, mainly locally originated and/or influenced by agriculture fires in the Himalayan foothills. A combination of CALIOP and PARASOL observations with ground-based measurements also highlights the dominance of biomass burning smoke (mixed with polluted continental) over the IGB during the middle of May in 2009. The variability in aerosol types found during the PrM season indicates the significant effect of natural/human activities, associated with different meteorological conditions, on aerosol behavior over the region.

Stoichiometric characteristics of nitrogen and phosphorus in major wetland vegetation of China

Aims Little is known on the stoichiometric characteristics of nitrogen (N) and phosphorus (P) in wetland vegetation across China. This work is aimed to study the stoichiometric characteristics of wetland vegetation in China, which are of great significance for revealing the coupling relationship between vegetation and habitats. Methods Based on previous studies, a data set comprising N and P contents and N:P of wetland vegetation attained from 649 observations in 52 study sites, was classified and analyzed, which concerned vegetation organs, growth periods, plant life forms, climate zones and wetland types. Important findings The geometric mean of N, P and the N:P of different organs occurred in descending order as follows: leaf (N, 16.07 mg·g; P, 1.85 mg·g; N:P, 8.67) > aboveground organ (N, 13.54 mg·g; P, 1.72 mg·g; N:P, 7.96) > stem (N, 7.86 mg·g; P, 1.71 mg·g; N:P, 4.58). Leaf N showed a three-peak seasonal distribution, with the peaks occurring in May, July and September, whilst stem N exhibited a bimodal distribution with peaks in May and September. Leaf N:P fluctuated in conformity to N before maturity, but changed corresponding to P in senescence phase. The type of wetlands was found to be the key factor significantly impacted the stoichiometric characteristics of wetland vegetation in China. Specifically, the highest and lowest leaf N and P contents were found in the bottom lands and marshes, respectively, while the N:P displayed a reversed trend. The geometric mean of leaf N, P contents and the N:P followed the order of: tropics > temperate zone > subtropics, albeit no significant differences (p > 0.05) among them. In addition, most of the leaf N:P were less than 14, indicating that the wetland vegetation in China was under the conditions of N limitation.

Investigating Annual Diving Behaviour by Hooded Seals (Cystophora cristata) within the Northwest Atlantic Ocean

With the exception of relatively brief periods when they reproduce and moult, hooded seals, Cystophora cristata, spend most of the year in the open ocean where they undergo feeding migrations to either recover or prepare for the next fasting period. Valuable insights into habitat use and diving behaviour during these periods have been obtained by attaching Satellite Relay Data Loggers (SRDLs) to 51 Northwest (NW) Atlantic hooded seals (33 females and 18 males) during ice-bound fasting periods (2004−2008). Using General Additive Models (GAMs) we describe habitat use in terms of First Passage Time (FPT) and analyse how bathymetry, seasonality and FPT influence the hooded seals’ diving behaviour described by maximum dive depth, dive duration and surface duration. Adult NW Atlantic hooded seals exhibit a change in diving activity in areas where they spend >20 h by increasing maximum dive depth, dive duration and surface duration, indicating a restricted search behaviour. We found that male and female hooded seals are spatially segregated and that diving behaviour varies between sexes in relation to habitat properties and seasonality. Migration periods are described by increased dive duration for both sexes with a peak in May, October and January. Males demonstrated an increase in dive depth and dive duration towards May (post-breeding/pre-moult) and August–October (post-moult/pre-breeding) but did not show any pronounced increase in surface duration. Females dived deepest and had the highest surface duration between December and January (post-moult/pre-breeding). Our results suggest that the smaller females may have a greater need to recover from dives than that of the larger males. Horizontal segregation could have evolved as a result of a resource partitioning strategy to avoid sexual competition or that the energy requirements of males and females are different due to different energy expenditure during fasting periods.

Epidemiological features and risk factors associated with the spatial and temporal distribution of human brucellosis in China

BackgroundHuman brucellosis incidence in China has been increasing dramatically since 1999. However, epidemiological features and potential factors underlying the re-emergence of the disease remain less understood.MethodsData on human and animal brucellosis cases at the county scale were collected for the year 2004 to 2010. Also collected were environmental and socioeconomic variables. Epidemiological features including spatial and temporal patterns of the disease were characterized, and the potential factors related to the spatial heterogeneity and the temporal trend of were analysed using Poisson regression analysis, Granger causality analysis, and autoregressive distributed lag (ADL) models, respectively.ResultsThe epidemic showed a significantly higher spatial correlation with the number of sheep and goats than swine and cattle. The disease was most prevalent in grassland areas with elevation between 800–1,600 meters. The ADL models revealed that local epidemics were correlated with comparatively lower temperatures and less sunshine in winter and spring, with a 1–7 month lag before the epidemic peak in May.ConclusionsOur findings indicate that human brucellosis tended to occur most commonly in grasslands at moderate elevation where sheep and goats were the predominant livestock, and in years with cooler winter and spring or less sunshine.

Moisture recycling and the maximum of precipitation in spring in the Iberian Peninsula

In the semiarid interior of the Iberian Peninsula, the topographic insulation from the surrounding seas promotes the role of internal sources of moisture and water recycling in the rainfall regime. In inland Iberia, the annual cycle of precipitation often has a distinctive peak in the springtime, when evapotranspiration (ET) is the highest, in contrast to the coastal areas, where it is more closely related to the external moisture availability and synoptic forcing, with a maximum in winter-autumn and a pronounced minimum in the summer. In this work we investigate the role of land surface water fluxes in the intensification of the hydrological cycle in the Iberian spring. We used data from 5 km resolution WRF-ARW model simulations over the Iberian Peninsula for eleven months of May (2000–2010). To bring out the effect of ET fluxes, we conducted experiments where ET water over land was removed from the system. Our findings indicate that the impact of ET on precipitation is on average very large (37 % increase). The impact is particularly strong in the interior north and northeast areas where the observed annual rainfall cycle has a peak in May, suggesting that the role of surface water fluxes is very important there. To investigate whether this role is as a water source or to amplify precipitation dynamics, we computed the recycling ratio analytically from the model data. In addition, we developed a procedure to quantify the amplification impact by comparing the recycling ratio and the relative change in precipitation between control and experiments with ET removed. Results show that the role of surface water fluxes on precipitation depends on large-scale forcing and moisture advection. When the synoptic forcing and moisture advection are strong, such as in fronts associated to Atlantic storms, the impact of ET fluxes is small. When there is potential for convection, as is commonly the case of late spring in the Iberian Peninsula, ET fluxes have a significant impact. Surface moisture fluxes moisten the boundary layer and increase moist static energy, strengthening convective processes, and their role goes from being a primary water source for precipitation (recycling) to have mostly an amplification effect as external moisture availability increases. Our findings show that for the eleven simulated May cases over the Iberian Peninsula, the role of ET fluxes in activating recycling is important and explains 27–58 % of their total impact on precipitation, depending on the method used to calculate the recycling ratio. This indicates that the complementary effect of ET on amplifying rainfall from external sources of moisture is comparable in magnitude to the recycling mechanism and important as well.

Age and reproduction of the finless porpoises, Neophocaena asiaeorientalis, in the Yellow Sea, Korea

A total of 116 finless porpoises, Neophocaena asiaeorientalis, were collected in the Yellow Sea off Korea. About 111 specimens were incidentally caught by stow nets on anchors from March to June 2010, and five were stranded in February 2011. Age was determined by counting dentinal growth layer groups (GLGs) in thin-sectioned teeth, and sexual maturity rating (SMR) was classified by investigating ovaries and testis macroscopically and microscopically. Immature females were ranged 1–4 years old and 92.6–141.2 cm in total body length (TBL), pubertal ones were all 5 years old and 125.4–136.0 cm, and mature ones ranged 5–19 years old and 131.6–155.2 cm. Age at attainment of sexual maturity of females was 4–5 years old. Parturition season estimated based on TBL of eight fetuses was from April to August with a peak in April to May. The first age at parturition was 5 years old. Among 62 males, immature males were 1–4 years old and 87.9–154.6 cm, pubertal ones were 3–5 years old and 121.5–134.5 cm, and mature ones were 4–19 years old and 125.3–229.0 cm. Males reached sexual maturity at 4–5 years old. Testicular mass and the diameters of seminiferous tubules were dramatically increased with SMR and regressed in testis of the individuals stranded in February. It suggested that male finless porpoises have aspermatogenic period between October and February. It is presumed that the breeding season would be May–September with a peak in May–June.