Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

International Nuclear Information System (INIS)

Rodriguez Pleguezuelo, C. R.; Duran Zuzo, V. H.; Martin Peinado, F. J.; Franco Tarifa, D.

2009-01-01

In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha - 1 yr - 1, and for runoff 34.1 and 6.8 mm yr - 1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Pleguezuelo, C. R.; Duran Zuzo, V. H.; Martin Peinado, F. J.; Franco Tarifa, D.

2009-07-01

In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha{sup -}1 yr{sup -}1, and for runoff 34.1 and 6.8 mm yr{sup -}1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

Condensation heating of the Asian summer monsoon and the subtropical anticyclone in the Eastern Hemisphere

Energy Technology Data Exchange (ETDEWEB)

Liu, Y.M.; Wu, G.X.; Liu, H.; Liu, P. [Chinese Academy of Sciences, Beijing (China). Inst. of Atmospheric Physics

2001-02-01

The effects of condensation heating on the formation of the subtropical anticyclone in the Eastern Hemisphere (EH) are studied by means of theoretical analysis and numerical simulation. The complete vorticity equation is employed for the analysis. It is found that, due to the vertical gradient of strong condensation heating, the distribution of cyclone and anticyclone in the upper troposphere is out of phase with that in the middle and lower troposphere. This is confirmed by a series of numerical experiments. The horizontal gradient of the condensation heating also affects the configuration of the subtropical anticyclone. It is concluded that condensation heating is a key factor for the formation and location of the summer subtropical anticyclone in the EH. The latent heating released by the Asian monsoon rainfall contributes to the formation of the 200 hPa South Asian anticyclone on the western side of the heating center and the 500 hPa western Pacific subtropical anticyclone on the eastern side of the center. Such configurations are modified to some extent by surface sensible heating and orography. The circulation in mid-latitudes is also affected by the latent heating in the subtropical area through the propagation of Rossby waves. (orig.)

Polycentric Structures in Latin American Metropolitan Areas : Identifying Employment Sub-centres

NARCIS (Netherlands)

Fernández-Maldonado, Ana María; Romein, Arie; Verkoren, Otto|info:eu-repo/dai/nl/073181773; Parente Paula Pessoa, Renata

2014-01-01

Fernández-Maldonado A. M., Romein A., Verkoren O. and Parente Paula Pessoa R. Polycentric structures in Latin American metropolitan areas: identifying employment sub-centres, Regional Studies. The significant spatial transformations that have occurred within Latin American metropolitan areas since

Long-Term Seasonal and Interannual Patterns of Marine Mammal Strandings in Subtropical Western South Atlantic

Science.gov (United States)

Prado, Jonatas H. F.; Mattos, Paulo H.; Silva, Kleber G.; Secchi, Eduardo R.

2016-01-01

Understanding temporal patterns of marine mammal occurrence is useful for establishing conservation strategies. We used a 38 yr-long dataset spanning 1976 to 2013 to describe temporal patterns and trends in marine mammal strandings along a subtropical stretch of the east coast of South America. This region is influenced by a transitional zone between tropical and temperate waters and is considered an important fishing ground off Brazil. Generalized Additive Models were used to evaluate the temporal stranding patterns of the most frequently stranded species. Forty species were documented in 12,540 stranding events. Franciscana (n = 4,574), South American fur seal, (n = 3,419), South American sea lion (n = 2,049), bottlenose dolphins (n = 293) and subantarctic fur seal (n = 219) were the most frequently stranded marine mammals. The seasonality of strandings of franciscana and bottlenose dolphin coincided with periods of higher fishing effort and strandings of South American and subantarctic fur seals with post-reproductive dispersal. For South American sea lion the seasonality of strandings is associated with both fishing effort and post-reproductive dispersal. Some clear seasonal patterns were associated with occurrence of cold- (e.g. subantarctic fur seal) and warm-water (e.g. rough-toothed dolphin) species in winter and summer, respectively. Inter-annual increases in stranding rate were observed for franciscana and South American fur seal and these are likely related to increased fishing effort and population growth, respectively. For subantarctic fur seal the stranding rate showed a slight decline while for bottlenose dolphin it remained steady. No significant year to year variation in stranding rate was observed for South American sea lion. The slight decrease in frequency of temperate/polar marine mammals and the increased occurrence of subtropical/tropical species since the late 1990s might be associated with environmental changes linked to climate change

Long-Term Seasonal and Interannual Patterns of Marine Mammal Strandings in Subtropical Western South Atlantic.

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Jonatas H F Prado

Full Text Available Understanding temporal patterns of marine mammal occurrence is useful for establishing conservation strategies. We used a 38 yr-long dataset spanning 1976 to 2013 to describe temporal patterns and trends in marine mammal strandings along a subtropical stretch of the east coast of South America. This region is influenced by a transitional zone between tropical and temperate waters and is considered an important fishing ground off Brazil. Generalized Additive Models were used to evaluate the temporal stranding patterns of the most frequently stranded species. Forty species were documented in 12,540 stranding events. Franciscana (n = 4,574, South American fur seal, (n = 3,419, South American sea lion (n = 2,049, bottlenose dolphins (n = 293 and subantarctic fur seal (n = 219 were the most frequently stranded marine mammals. The seasonality of strandings of franciscana and bottlenose dolphin coincided with periods of higher fishing effort and strandings of South American and subantarctic fur seals with post-reproductive dispersal. For South American sea lion the seasonality of strandings is associated with both fishing effort and post-reproductive dispersal. Some clear seasonal patterns were associated with occurrence of cold- (e.g. subantarctic fur seal and warm-water (e.g. rough-toothed dolphin species in winter and summer, respectively. Inter-annual increases in stranding rate were observed for franciscana and South American fur seal and these are likely related to increased fishing effort and population growth, respectively. For subantarctic fur seal the stranding rate showed a slight decline while for bottlenose dolphin it remained steady. No significant year to year variation in stranding rate was observed for South American sea lion. The slight decrease in frequency of temperate/polar marine mammals and the increased occurrence of subtropical/tropical species since the late 1990s might be associated with environmental changes linked to

The Role of Subtropical Intrusion in the Development of Typhoon Usagi (5W) 2007

National Research Council Canada - National Science Library

DeLeon, Raymund P

2008-01-01

... of a decaying baroclinic system in the WNP. This analysis of the formation of Usagi points to sub-tropical intrusion of a strong lower-tropospheric baroclinic system undergoing decay as potential seedlings for typhoon formation in areas...

Latin American protected areas: Protected from chemical pollution?

Science.gov (United States)

Rodríguez-Jorquera, Ignacio A; Siroski, Pablo; Espejo, Winfred; Nimptsch, Jorge; Choueri, Paloma Gusso; Choueri, Rodrigo Brasil; Moraga, Claudio A; Mora, Miguel; Toor, Gurpal S

2017-03-01

Protected areas (PAs) are critically important means to preserve species and maintain natural ecosystems. However, the potential impacts of chemical pollution on PAs are seldom mentioned in the scientific literature. Research on the extent of the occurrence of chemical pollution inside PAs and in-depth assessments of how chemical contaminants may adversely affect the maintenance of species abundance, species survival, and ecosystem functions are scarce to nonexistent. We investigated 1) the occurrence of chemical contaminants inside 119 PAs in Latin America from publically available databases, and 2) reviewed case studies of chemical contaminants and pollution in 4 Latin American PAs. Cases of chemical pollution and contamination inside Latin American PAs mostly originated from sources such as mining, oil, and gas extraction. To date, the focus of the research on chemical pollution research inside Latin American PAs has been primarily on the detection of contamination, typically limited to trace metals. Where management actions have occurred, they have been reactive rather than proactive. Protected areas established in wetlands are the most affected by chemical pollution. Based on the information from the pollution and/or contamination occurrence and the case studies analyzed, Latin American PAs are not well safeguarded from chemical pollution, resulting in both challenges and opportunities to conserve biodiversity and ecosystems. Integr Environ Assess Manag 2017;13:360-370. © 2016 SETAC. © 2016 SETAC.

Alkalithermophilic actinomycetes in a subtropical area of Jujuy, Argentina Actinomicetos termoalcalófilos del área subtropical de Jujuy, Argentina

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L. Carrillo

2009-06-01

Full Text Available The objective of this study was to examine the alkalithermophilic actinomycete communities in the subtropical environment of Jujuy, Argentina, characterized by sugarcane crops. Laceyella putida, Laceyella sacchari, Thermoactinomyces intermedius, Thermoactinomyces vulgaris and Thermoflavimicrobium dichotomicum were isolated on the media with novobiocin, from sugar cane plants and renewal rhizospheres, and grass and wood soils. Soil pH was almost neutral or lightly alkaline, except for grass soil acidified by lactic liquor. A smaller number of actinomycetes was found on the living plants and bagasse (recently obtained or stored according to the Ritter method with respect to decomposed leaves on the soil. Thermophilic species of Laceyella, Thermoactinomyces, Thermoflavimicrobium, Saccharomonospora, Streptomyces and Thermononospora were isolated on the media without novobiocin, from composted sugar cane residues. Air captured near composted bagasse piles, contained alkalithermophilic actinomycete spores.El objetivo de este trabajo fue examinar los actinomicetos termoalcalófilos presentes en el área subtropical de Jujuy, Argentina, caracterizada por el cultivo de la caña de azúcar. Se aislaron en medio con novobiocina las especies Laceyella putida, Laceyella sacchari, Thermoactinomyces intermedius, Thermoactinomyces vulgaris y Thermoflavimicrobium dichotomicum a partir de la rizósfera de plantas y de renuevos de caña de azúcar, así como de suelos de pastura y de monte natural. El pH de los suelos era casi neutro a ligeramente alcalino, excepto en un solo caso en que el suelo estaba acidificado por licor láctico. El número de actinomicetos encontrados sobre los tejidos vivos y en el bagazo recién obtenido o almacenado según el método de Ritter fue pequeño en comparación con el observado sobre las hojas en descomposición. L. sacchari predominó respecto de T. vulgaris. Se aislaron especies termoalcalófilas de Laceyella

Coastal Culture Area. Native American Curriculum Series.

Science.gov (United States)

Ross, Cathy; Fernandes, Roger

Background information, legends, games, illustrations, and art projects are provided in this booklet introducing elementary students to the history and culture of Indian tribes of the North Pacific Coast and Pacific Northwest. One in a series of Native American instructional materials, the booklet provides an overview of the coastal culture area,…

Tsunami hazard mitigation in tourism in the tropical and subtropical coastal areas: a case study in the Ryukyu Islands, southwest of Japan

Science.gov (United States)

Matsumoto, T.

2006-12-01

Life and economy (including tourism) in tropical and subtropical coastal areas, such as Okinawa Prefecture (Ryukyu) are highly relying on the sea. The sea has both "gentle" side to give people healing and "dangerous" side to kill people. If we are going to utilise the sea for marine tourism such as constructing resort facilities on the oceanfront, we should know all of the sea, including the both sides of the sea: especially the nature of tsunamis. And also we islanders should issue accurate information about the sea towards outsiders, especially tourists visiting the island. We have already learned a lesson about this issue from the Sumatra tsunami in 2004. However, measures against the tsunami disaster by marine tourism industry are still inadequate in these areas. The goal of tsunami hazard mitigation for those engaged in tourism industry in tropical and subtropical coastal areas should be as follows. (1) Preparedness against tsunamis: "Be aware of the characteristics of tsunamis." "Prepare tsunamis when you feel an earthquake." "Prepare tsunamis when an earthquake takes place somewhere in the world." (2) Maintenance of an exact tsunami hazard map under quantitative analyses of the characteristics of tsunamis: "Flooding areas by tsunami attacks are dependent not only on altitude but also on amplification and inundation due to the seafloor topography near the coast and the onland topographic relief." "Tsunami damage happens repeatedly." (3) Maintenance of a tsunami disaster prevention manual and training after the manual: "Who should do what in case of tsunamis?" "How should the resort hotel employees lead the guests to the safe place?" Such a policy for disaster prevention is discussed in the class of the general education of "Ocean Sciences" in University of the Ryukyus (UR) and summer school for high school students. The students (most of them are from Okinawa Prefecture) consider, discuss and make reports about what to do in case of tsunamis as an islander

Sub-tropical coastal lagoon salinization associated to shrimp ponds effluents

Science.gov (United States)

Cardoso-Mohedano, José-Gilberto; Lima-Rego, Joao; Sanchez-Cabeza, Joan-Albert; Ruiz-Fernández, Ana-Carolina; Canales-Delgadillo, Julio; Sánchez-Flores, Eric-Ivan; Páez-Osuna, Federico

2018-04-01

Anthropogenic salinization impacts the health of aquatic and terrestrial ecosystems worldwide. In tropical and subtropical areas, shrimp farm aquaculture uses water from adjacent ecosystems to fill the culture ponds, where enhanced evaporation cause salinization of discharged water. In this study, we studied water salinity before and after shrimp farm harvest and implemented a three-dimensional hydrodynamic model to assess the impact on a subtropical coastal lagoon that receives water releases from shrimp ponds. The shrimp pond discharge significantly increased the salinity of receiving waters, at least 3 psu over the local variation. In the worst-case salinization scenario, when harvest occurs after a long dry season, salinity could increase by up to 6 psu. The induced salinization due to shrimp pond effluents remained up to 2 tidal cycles after harvest, and could affect biota. The methodology and results of this study can be used to assess the impacts of shrimp aquaculture worldwide.

Metal contamination of vineyard soils in wet subtropics (southern Brazil)

International Nuclear Information System (INIS)

Mirlean, Nicolai; Roisenberg, Ari; Chies, Jaqueline O.

2007-01-01

The vine-growing areas in Brazil are the dampest in the world. Copper maximum value registered in this study was as much as 3200 mg kg -1 , which is several times higher than reported for vineyard soils in temperate climates. Other pesticide-derived metals accumulate in the topsoil layer, surpassing in the old vineyards the background value several times for Zn, Pb, Cr and Cd. Copper is transported to deeper soils' horizons and can potentially contaminate groundwater. The soils from basaltic volcanic rocks reveal the highest values of Cu extracted with CaCl 2 , demonstrating a high capacity of copper transference into plants. When evaluating the risks of copper's toxic effects in subtropics, the soils from rhyolitic volcanic rocks are more worrisome, as the Cu extracted with ammonium acetate 1 M surpasses the toxic threshold as much as 4-6 times. - Copper-based pesticide use in wet subtropics is environmentally more risky

Holocene temperature variability revealed by brGDGTs in subtropical southwestern China

Science.gov (United States)

Feng, X.; Zhao, C.

2017-12-01

Subtropical areas are important source region of moisture and heat in global climate system. Paleoclimate reconstructions from these regions, especially quantitative records, would not only help to better understand the nature of climate system through time, but also provide important constraining dataset for long-term ecosystem variations in these ecological important areas. To date, quantitative climate records with reliable chronological controls are still limited from terrestrial archives in subtropical areas. Here we present a 50-year-resolution quantitative temperature record throughout the Holocene based on branched GDGTs at a small alpine lake, Tiancai Lake (26°38'E, 99°43'N, 3898 m.a.s.l) in southwestern China. The record is based on a temporal calibration between instrumental mean annual air temperature (MAAT) and brGDGT compounds (GDGT-IIIa, GDGT-IIa', GDGT-IIb, GDGT-Ia and GDGT-Ic). The MAAT was relatively low -0.6 ° between 11 and 7.5 ka, then abruptly increased 1 ° to 4 °until 7 ka. The MAAT was relatively warm 2° between 7 and 1 ka, then decreased to 1° over the last 1 ka. The Middle to Late Holocene was 3 ° warmer than the Early Holocene. The MAAT variation at Lake Tiancai is supported by changes in evergreen oaks and Tsuga from the same sediment core, suggesting that the growth of cold-tolerant forest in place of subtropical evergreen broadleaved forest has been driven by the decrease in MAAT. The early Holocene cold interval revealed by our record and pollen data is different with the chironomid-based summer temperature reconstruction from the same lake, the latter has been driven by summer insolation. This difference suggests that a pronounced winter contribution to the mean annual temperature during the early Holocene, which was probably caused by a low winter insolation, and strengthened by a sparse vegetation cover and influences of winter ice/snow cover in tropical high latitude regions.

Stalagmite water content as a proxy for drip water supply in tropical and subtropical areas

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N. Vogel

2013-01-01

Full Text Available In this pilot study water was extracted from samples of two Holocene stalagmites from Socotra Island, Yemen, and one Eemian stalagmite from southern continental Yemen. The amount of water extracted per unit mass of stalagmite rock, termed "water yield" hereafter, serves as a measure of its total water content. Based on direct correlation plots of water yields and δ18Ocalcite and on regime shift analyses, we demonstrate that for the studied stalagmites the water yield records vary systematically with the corresponding oxygen isotopic compositions of the calcite (δ18Ocalcite. Within each stalagmite lower δ18Ocalcite values are accompanied by lower water yields and vice versa. The δ18Ocalcite records of the studied stalagmites have previously been interpreted to predominantly reflect the amount of rainfall in the area; thus, water yields can be linked to drip water supply. Higher, and therefore more continuous drip water supply caused by higher rainfall rates, supports homogeneous deposition of calcite with low porosity and therefore a small fraction of water-filled inclusions, resulting in low water yields of the respective samples. A reduction of drip water supply fosters irregular growth of calcite with higher porosity, leading to an increase of the fraction of water-filled inclusions and thus higher water yields. The results are consistent with the literature on stalagmite growth and supported by optical inspection of thin sections of our samples. We propose that for a stalagmite from a dry tropical or subtropical area, its water yield record represents a novel paleo-climate proxy recording changes in drip water supply, which can in turn be interpreted in terms of associated rainfall rates.

Water use in the tropics and subtropics and human health

OpenAIRE

Rodrigues, Manoel Gonçalves; Universidade Federal do Rio de Janeiro; Centro Universitário da Cidade; Almeida, Josimar Ribeiro de; Universidade Federal do Rio de Janeiro; Bahé, Jackeline Maria Cardoso de França; Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro

2011-01-01

The main purpose of this paper is to analyze the environmental degradation and its effects in the human health particularly related to the use of water of the tropics and subtropics areas on Earth. In this conception towards a healthy society a continuous investing in basic and environmental sanitation is very important and simultaneously less expensive than dealing with illnesses. In order to improve a better and friendly society linked to Sustainable Development with a good population life ...

Why do we lose protected areas? Factors influencing protected area downgrading, downsizing and degazettement in the tropics and subtropics.

Science.gov (United States)

Symes, William S; Rao, Madhu; Mascia, Michael B; Carrasco, L Roman

2016-02-01

Protected areas (PAs) are an essential tool for the conservation of biodiversity globally. Previous studies have focussed on the effectiveness of PAs and the design of optimal PA networks. However, not all PAs remain intact permanently; many PAs undergo downgrading, downsizing and/or degazettement (PADDD), a fact largely ignored until recently. The drivers of enacted PADDD events and the factors influencing its spatial occurrence are poorly understood, potentially undermining the efficacy of PAs and PA networks. Here we examine the spatial relationship between PADDD and economic, demographic and structural variables, using a 110-year data set of 342 enacted PADDD events across 44 countries in the tropics and subtropics. We find that the probability of an enacted PADDD event increases with the size of the PA and through a synergistic interaction between PA size and local population densities. Our results are robust to the under-reporting of enacted PADDD events that occur among smaller PAs and in regions with lower population density. We find an economic motive for PADDD events, given that the opportunity costs associated with larger PAs are higher, on average, than smaller PAs. Our findings suggest a need for conservation practitioners to better consider PA characteristics, as well as the social, economic and political context in which PAs are situated, to aid the creation of more efficient and sustainable PA networks. In particular, the dynamics of enacted PADDD events highlight the need to explicitly consider PA robustness as a core component of systematic conservation planning for PA networks. © 2015 John Wiley & Sons Ltd.

Environmental radioactivity investigations in the Georgian subtropical region

International Nuclear Information System (INIS)

Pagava, S.; Kakashvili, P.; Avtandilashvili, M.; Kharashvili, G.; Robakidze, Z.; Rusetski, V.; Togonidze, G.; Baratashvili, D.

2002-01-01

Environmental changes in the contamination of the Georgian subtropical region have been investigated by analysing anthropogenic and natural radionuclides in samples of soil and tea leaves for possible chromosome mutations. As the tea industry in Georgia is an important economic activity, such investigations are of great importance. The changes in the morphology of tea leaves, their colour, blossoming, growth inhibition or stimulation, prolongation of the germination period and levels of tanin-katechin complexes have been investigated. The results of radionuclide measurements in soil and tea leaves ( 40 K, 210 Pb and 137 Cs) are presented. Elevated concentrations of 137 Cs were observed in soil samples due to fallout from Chernobyl, however, no direct relationship between the concentration of 137 Cs in soil and tea leaves has been observed. Cyto-genetic analyses of tea primary roots will be presented and compared for different time periods. Further, ichtyofauna samples taken from the Georgian subtropical areas were analysed for anthropogenic ( 137 Cs) and natural ( 40 K) radionuclides. The observed concentrations of 137 Cs were low, close to the detection limit of the order of 0.4 Bq/kg dry weight. Some of the investigations were carried out in the framework of the IAEA Technical Co-operation project 'Marine Environmental Assessment of the Black Sea Region'

Taxonomic survey and characterization of the habitat of aquatic insects in protected areas in a subtropical island

Directory of Open Access Journals (Sweden)

Jéssica da Rosa Pires

2015-09-01

Full Text Available Taxonomic inventories are the basis of several ecological studies and they enable a better understanding of the local and regional biodiversity. This paper aimed to survey the aquatic insect fauna in a subtropical island, as well as to generate information on the habitats used by the taxa found. Two regions showing a good state of environmental conservation in the Santa Catarina Island, in Santa Catarina, Brazil, were selected: “Lagoa do Peri” Municipal Park and “Desterro” Environmental Protected Area. Aquatic invertebrates were collected by using a Surber sampler (in a lotic environment and an Eckman-Birge dredger (in a lentic environment between 2009 and 2012. Sixty taxa were found, belonging to eight taxonomic orders. Thus, there were 19 new registers of aquatic insect families for Santa Catarina. At the sites of this study, 13 families already known for Santa Catarina were not observed, according to a comparison with articles published until July 2014. As for the habitat, richness differed between the types of the habitats sampled, with lower richness in the substrate “sand”. The study represents a significant contribution to knowledge on aquatic insects in Santa Catarina, especially regarding the biodiversity in islands.

Temporal dynamics of a subtropical urban forest in San Juan, Puerto Rico, 2001-2010

Science.gov (United States)

J. M. Tucker Lima; C. L. Staudhammer; T. J. Brandeis; F. J. Escobedo; W. Zipperer

2013-01-01

Several studies report urban tree growth and mortality rates as well as species composition, structural dynamics, and other characteristics of urban forests in mostly temperate, inland urban areas. Temporal dynamics of urban forests in subtropical and tropical forest regions are, until now, little explored and represent a new and important direction for study and...

Pleistocene niche stability and lineage diversification in the subtropical spider Araneus omnicolor (Araneidae.

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Elen A Peres

Full Text Available The influence of Quaternary climate oscillations on the diversification of the South American fauna is being increasingly explored. However, most of these studies have focused on taxa that are endemic to tropical environments, and relatively few have treated organisms restricted to subtropical biomes. Here we used an integrative phylogeographical framework to investigate the effects of these climate events on the ecological niche and genetic patterns of the subtropical orb-weaver spider Araneus omnicolor (Araneidae. We analyzed the mitochondrial (Cytochrome Oxidase I, COI and nuclear (Internal Transcribed Subunit II, ITS2 DNA of 130 individuals throughout the species' range, and generated distribution models in three different climate scenarios [present, Last Glacial Maximum (LGM, and Last Interglacial Maximum (LIG]. Additionally, we used an Approximate Bayesian Computation (ABC approach to compare possible demographic scenarios and select the hypothesis that better explains the genetic patterns of A. omnicolor. We obtained high haplotype diversity but low nucleotide variation among sequences. The population structure and demographic analyses showed discrepancies between markers, suggesting male-biased dispersal in the species. The time-calibrated COI phylogenetic inference showed a recent diversification of lineages (Middle/Late Pleistocene, while the paleoclimate modeling indicated niche stability since ~120 Kya. The ABC results agreed with the niche models, supporting a panmictic population as the most likely historical scenario for the species. These results indicate that A. omnicolor experienced no niche or population reductions during the Late Pleistocene, despite the intense landscape modifications that occurred in the subtropical region, and that other factors beside LGM and LIG climate oscillations might have contributed to the demographic history of this species. This pattern may be related to the high dispersal ability and wide

A Reassessment of the Integrated Impact of Tropical Cyclones on Surface Chlorophyll in the Western Subtropical North Atlantic

Energy Technology Data Exchange (ETDEWEB)

Foltz, Gregory R.; Balaguru, Karthik; Leung, Lai-Yung R.

2015-02-28

The impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998–2011. Previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone-induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of cyclone-induced changes in mixed layer depth, here it is shown that accumulated cyclone energy explains 22% of the interannual variability in seasonally-averaged (June–November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explained by tropical cyclones is thus about 70% of that explained by the NAO, which has well-known impacts in this region. It is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.

The Ocean deserts:salt budgets of northern subtropical oceans and their

KAUST Repository

Carton, Jim

2011-04-09

The Ocean deserts: salt budgets of northern subtropical oceans and their relationship to climate variability The high salinity near surface pools of the subtropical oceans are the oceanic deserts, with high levels of evaporation and low levels of precip

Management practices and controls on methane emissions from sub-tropical wetlands

Science.gov (United States)

DeLucia, Nicholas; Casa-Nova Gomez, Nuri; Bernacchi, Carl

2015-04-01

It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on any combination of climate conditions, natural and anthropogenic disturbances, or ecosystem perturbations. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are the main source for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. CH4 is one of the most damaging green house gases with current emission estimates ranging from 55 to 231 Tg CH4 yr-1. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04"N, 81o21'8.56"W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified

Explosive development of winter storm Xynthia over the subtropical North Atlantic Ocean

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M. L. R. Liberato

2013-09-01

Full Text Available In winter of 2009–2010 south-western Europe was hit by several destructive windstorms. The most important was Xynthia (26–28 February 2010, which caused 64 reported casualties and was classified as the 2nd most expensive natural hazard event for 2010 in terms of economic losses. In this work we assess the synoptic evolution, dynamical characteristics and the main impacts of storm Xynthia, whose genesis, development and path were very uncommon. Wind speed gusts observed at more than 500 stations across Europe are evaluated as well as the wind gust field obtained with a regional climate model simulation for the entire North Atlantic and European area. Storm Xynthia was first identified on 25 February around 30° N, 50° W over the subtropical North Atlantic Ocean. Its genesis occurred on a region characterized by warm and moist air under the influence of a strong upper level wave embedded in the westerlies. Xynthia followed an unusual SW–NE path towards Iberia, France and central Europe. The role of moist air masses on the explosive development of Xynthia is analysed by considering the evaporative sources. A lagrangian model is used to identify the moisture sources, sinks and moisture transport associated with the cyclone during its development phase. The main supply of moisture is located over an elongated region of the subtropical North Atlantic Ocean with anomalously high SST, confirming that the explosive development of storm Xynthia had a significant contribution from the subtropics.

Intra-population variation in activity ranges, diel patterns, movement rates, and habitat use of American alligators in a subtropical estuary

Science.gov (United States)

Rosenblatt, Adam E.; Heithaus, Michael R.; Mazzotti, Frank J.; Cherkiss, Michael; Jeffery, Brian M.

2013-12-01

Movement and habitat use patterns are fundamental components of the behaviors of mobile animals and help determine the scale and types of interactions they have with their environments. These behaviors are especially important to quantify for top predators because they can have strong effects on lower trophic levels as well as the wider ecosystem. Many studies of top predator movement and habitat use focus on general population level trends, which may overlook important intra-population variation in behaviors that now appear to be common. In an effort to better understand the prevalence of intra-population variation in top predator movement behaviors and the potential effects of such variation on ecosystem dynamics, we examined the movement and habitat use patterns of a population of adult American alligators (Alligator mississippiensis) in a subtropical estuary for nearly four years. We found that alligators exhibited divergent behaviors with respect to activity ranges, movement rates, and habitat use, and that individualized behaviors were stable over multiple years. We also found that the variations across the three behavioral metrics were correlated such that consistent behavioral types emerged, specifically more exploratory individuals and more sedentary individuals. Our study demonstrates that top predator populations can be characterized by high degrees of intra-population variation in terms of movement and habitat use behaviors that could lead to individuals filling different ecological roles in the same ecosystem. By extension, one-size-fits-all ecosystem and species-specific conservation and management strategies that do not account for potential intra-population variation in top predator behaviors may not produce the desired outcomes in all cases.

Okinawan Subtropical Plants as a Promising Resource for Novel Chemical Treasury.

Science.gov (United States)

Matsunami, Katsuyoshi; Otsuka, Hideaki

2018-01-01

The Okinawa Islands are a crescent-shaped archipelago and their natural forests hold a huge variety of unique subtropical plants with relatively high endemism. We have performed phytochemical study on Okinawan subtropical plants for many years. In this review, we describe our recent research progress on the isolation of new compounds and their various bioactivities.

Subduction in the Subtropical Gyre: Seasoar Cruises Data Report

Science.gov (United States)

1995-09-01

Julie Pallant , Frank Bahr, Terrence Joyce, Jerome Dean, James R. Luyten & Performing Organization Rept No. WHOI-95- 13 IL Performing Organization Name...AD-A28 6 861 WHOI-95-13 Woods Hole x Oceanc grapbic Ifliotitutionf de Subduction in the Subtropical Gyre: Seasoar Cruises Data Report by Julie S. •P...unlimiled. =Tfl QUALuTr =S) ij Ai Si 4 ;•IIII.. " - II •r * 9 9 * 11S 0 WIHOI-95-13 Subduction in the Subtropical Gyre: Seasoar Cruises Data Report by 0 Julie

Breast cancer among American Japanese in the San Francisco Bay area.

Science.gov (United States)

Dunn, J E

1977-12-01

The Japanese-American population was particularly well suited for the study of cancer occurrence because: 1) An American-born population as well as the immigrant Japanese-American population could be studied; 2) good cancer incidence and mortality data from Japan could be compared with data from the United States; and 3) some differences in the rate of occurrence of several specific cancer sites in Japan as compared with the United States were striking. The most significant of these involved the gastrointestinal tract and sex organs. Data were presented concerning cancer incidence rates for the Japanese-American population of the San Francisco Bay area. The high gastric rates for the Japanese in Japan were reduced in a stepwise fashion in the immigrant Japanese-American population to the American-born Japanese who were approaching the low rate of the United States. Colon cancer rates, which were low in Japan, approached the rates in the United States in both the immigrants from Japan and in Japanese Americans. The low rates of cancers of the breast, uterine corpus, and ovary of Japanese women in Japan and for prostate cancer among men rapidly approached the higher rates for these cancer sites that existed in the United States. A study of nutritional factors related to the increase of cancer of the breast in Japanese Americans is being conducted.

Agroecology and biodiversity of the catchment area of Swat River

International Nuclear Information System (INIS)

Ahmad, H.; Ahmed, R.

2003-01-01

Agroecological studies of the of the Swat River catchment area showed that the terrestrial ecosystem of the area is divided into subtropical, humid temperate, cool temperate, cold temperate, subalpine, alpine and cold desert zones. Indicator species along with their altitudinal limits are specified for each zone. Unplanned population growth, agriculture extension, habitat losses, deforestation, environmental pollution and unwise use of natural resources are threats to the natural biodiversity of these zones. Its severity is very evident in the subtropical and humid temperate zones. The losses encountered to the biodiversity of the area under the influence of various anthropogenic stresses are highlighted. (author)

Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. II. Protozooplankton and copepods

DEFF Research Database (Denmark)

Andersen, Nikolaj G.; Nielsen, Torkel Gissel; Jakobsen, Hans Henrik

2011-01-01

the potential reasons why Atlantic eels Anguilla spp. use this area for spawning, we investigated the distribution and productivity of the zooplankton community across the Subtropical Convergence Zone (STCZ) in the Sargasso Sea in March and April 2007. The vertical and horizontal distributions of protozoans...

Nitrate source apportionment in a subtropical watershed using Bayesian model

International Nuclear Information System (INIS)

Yang, Liping; Han, Jiangpei; Xue, Jianlong; Zeng, Lingzao; Shi, Jiachun; Wu, Laosheng; Jiang, Yonghai

2013-01-01

Nitrate (NO 3 − ) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (September 2011 to July 2012). The highest NO 3 − concentration in water was in May (wet season, mean ± SD = 17.45 ± 9.50 mg L −1 ) and the lowest concentration occurred in December (dry season, mean ± SD = 10.54 ± 6.28 mg L −1 ). Nevertheless, no water sample in the study area exceeds the WHO drinking water limit of 50 mg L −1 NO 3 − . Four sources of NO 3 − (atmospheric deposition, AD; soil N, SN; synthetic fertilizer, SF; manure and sewage, M and S) were identified using both hydrochemical characteristics [Cl − , NO 3 − , HCO 3 − , SO 4 2− , Ca 2+ , K + , Mg 2+ , Na + , dissolved oxygen (DO)] and dual isotope approach (δ 15 N–NO 3 − and δ 18 O–NO 3 − ). Both chemical and isotopic characteristics indicated that denitrification was not the main N cycling process in the study area. Using a Bayesian model (stable isotope analysis in R, SIAR), the contribution of each source was apportioned. Source apportionment results showed that source contributions differed significantly between the dry and wet season, AD and M and S contributed more in December than in May. In contrast, SN and SF contributed more NO 3 − to water in May than that in December. M and S and SF were the major contributors in December and May, respectively. Moreover, the shortcomings and uncertainties of SIAR were discussed to provide implications for future works. With the assessment of temporal variation and sources of NO 3 − , better agricultural management practices and sewage disposal programs can be implemented to sustain water quality in subtropical watersheds

N2O production pathways in the subtropical acid forest soils in China

International Nuclear Information System (INIS)

Zhang Jinbo; Cai Zucong; Zhu Tongbin

2011-01-01

To date, N 2 O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15 N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N 2 O production in four subtropical acid forest soils (pH 2 O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N 2 O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N 2 O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N 2 O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N 2 O product ratios from nitrification. The ratio of N 2 O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N 2 O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N 2 O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N 2 O production. → While, contribution of autotrophic nitrification to N 2 O production was little. → Ratios of N 2 O-N emission from nitrification were higher than those in most previous references.

Divergent profile of emerging cutaneous leishmaniasis in subtropical Brazil: new endemic areas in the southern frontier.

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Mariel Asbury Marlow

Full Text Available BACKGROUND: Although known to be highly endemic in the Amazon regions of Brazil, the presence of cutaneous leishmaniasis (CL in the subtropical southern part of the country has largely been ignored. This study was conducted to demonstrate CL is emerging in the Brazilian state of Santa Catarina, as well as to characterize the epidemiological profile and Leishmania species involved. METHODOLOGY/PRINCIPAL FINDINGS: For this cross-sectional study, data from all CL cases from Santa Catarina, Brazil, reported to the Brazilian National Notifiable Diseases Information System from 2001 to 2009 were investigated. Amplification of the kDNA minicircle conserved region followed by restriction fragment length polymorphism (PCR-RFLP was conducted to screen for Leishmania species present in patient biopsy. Overall, 542 CL cases were reported, with majority resulting from autochthonous transmission (n = 401, 73.99% and occurring in urban zones (n = 422, 77.86%. Age, gender, zone of residence, origin of case, clinical form and case outcome were found to differ significantly by region. Imported cases were over seven times more likely to relapse (95% CI 2.56-21.09. Mapping of cases revealed new endemic areas in northeastern Santa Catarina with two species present. With the exception of three L. (Leishmania amazonensis cases (1.20%, majority of PCR positive samples were found to be L. (Viannia braziliensis (n = 248, 98.80%. CONCLUSIONS/SIGNIFICANCE: CL is now endemic in the state of Santa Catarina, Brazil, with case profiles varying significantly by region. L. (V. braziliensis has been identified as the predominant species in the region.

Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

Science.gov (United States)

Tian, Di; Li, Peng; Fang, Wenjing; Xu, Jun; Luo, Yongkai; Yan, Zhengbing; Zhu, Biao; Wang, Jingjing; Xu, Xiaoniu; Fang, Jingyun

2017-07-01

Reactive nitrogen (N) increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m × 20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings), and ground-cover plants (ferns) according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height) of 5-10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha-1 yr-1) and N100 fertilized plots (100 kg N ha-1 yr-1), while the growth of median and large trees with a DBH of > 10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical forest, and that the limitation of other nutrients in the forest

Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

Directory of Open Access Journals (Sweden)

D. Tian

2017-07-01

Full Text Available Reactive nitrogen (N increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m  ×  20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings, and ground-cover plants (ferns according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height of 5–10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha−1 yr−1 and N100 fertilized plots (100 kg N ha−1 yr−1, while the growth of median and large trees with a DBH of  >  10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical

Community-weighted mean of leaf traits and divergence of wood traits predict aboveground biomass in secondary subtropical forests.

Science.gov (United States)

Ali, Arshad; Yan, En-Rong; Chang, Scott X; Cheng, Jun-Yang; Liu, Xiang-Yu

2017-01-01

Subtropical forests are globally important in providing ecological goods and services, but it is not clear whether functional diversity and composition can predict aboveground biomass in such forests. We hypothesized that high aboveground biomass is associated with high functional divergence (FDvar, i.e., niche complementarity) and community-weighted mean (CWM, i.e., mass ratio; communities dominated by a single plant strategy) of trait values. Structural equation modeling was employed to determine the direct and indirect effects of stand age and the residual effects of CWM and FDvar on aboveground biomass across 31 plots in secondary forests in subtropical China. The CWM model accounted for 78, 20, 6 and 2% of the variation in aboveground biomass, nitrogen concentration in young leaf, plant height and specific leaf area of young leaf, respectively. The FDvar model explained 74, 13, 7 and 0% of the variation in aboveground biomass, plant height, twig wood density and nitrogen concentration in young leaf, respectively. The variation in aboveground biomass, CWM of leaf nitrogen concentration and specific leaf area, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf explained by the joint model was 86, 20, 13, 7, 2 and 0%, respectively. Stand age had a strong positive direct effect but low indirect positive effects on aboveground biomass. Aboveground biomass was negatively related to CWM of nitrogen concentration in young leaf, but positively related to CWM of specific leaf area of young leaf and plant height, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf. Leaf and wood economics spectra are decoupled in regulating the functionality of forests, communities with diverse species but high nitrogen conservative and light acquisitive strategies result in high aboveground biomass, and hence, supporting both the mass ratio and niche complementarity hypotheses in secondary subtropical forests

The nitrate export in subtropical mountainous catchment: implication for land use change impact

Science.gov (United States)

Huang, J.-C.; Lee, T.-Y.; Kao, S.-J.; Hsu, S.-C.; Lin, H.-J.; Peng, T.-R.

2010-12-01

Agricultural activity is the dominant factor affecting water quality and nitrate export, which causes eutrophication and episodic acidification in downstream water bodies (e.g., reservoirs, lakes, and coastal zones). However, in subtropical mountainous areas such environmental impact due to the land use change was rarely documented. In this study, we investigated 16 sub-catchments during 2007 and 2008 in the Chi-Chia-Wan catchment where is the sole habitat for the endemic species, Formosan landlocked salmon (Oncorhynchus masou formosanus). The results revealed that the NO3-N concentration in pristine catchments varied from 0.144 to 0.151 mg/L without significant seasonal variation. This concentration was comparable with other forestry catchments around the world. However, the annual nitrate export was around 375.3-677.1 kg/km2/yr, much higher than other catchments due to the greater amount of rainfall. This is an important baseline for comparisons with other climate areas. As for the impact of agricultural activities, the catchments with some human disturbance, ~5.2% of the catchment area, might yield 5947.2 kg N/km2/yr - over 10-times higher than that of pristine catchment. Such high export caused by such a low level of disturbance might indicate that subtropical mountainous area is highly sensitive to agricultural activities. As for the land-use effect on nitrate yield, the forestry land might yield 488.5 ± 325.1 kg/km2/yr and the vegetable farm could yield 298 465.4 ± 3347.2 kg/km2/yr - 1000-times greater than the forestry. The estimated nitrate yields for land use classes were a crucial basis and useful for the land manager to assess the possible impacts (e.g., non-point source pollution evaluation and the recovery of land expropriation).

An observational study of the carbon-sink strength of East Asian subtropical evergreen forests

International Nuclear Information System (INIS)

Tan Zhenghong; Zhang Yiping; Zhang Yongjiang; Song Qinhai; Cao Kunfang; Schaefer, D A; Liu Yuhong; Liang Naishen; Hsia, Yue-Joe; Zhou Guoyi; Li Yuelin; Yan Junhua; Juang, Jehn-Yih; Chu Housen; Yu Guirui; Sun Xiaomin

2012-01-01

Relatively little is known about the effects of regional warming on the carbon cycle of subtropical evergreen forest ecosystems, which are characterized by year-round growing season and cold winters. We investigated the carbon balance in three typical East Asia subtropical evergreen forests, using eddy flux, soil respiration and leaf-level measurements. Subtropical evergreen forests maintain continuous, high rates of photosynthetic activity, even during winter cold periods. Warm summers enhance photosynthetic rates in a limited way, because overall ecosystem productivity is primarily restrained by radiation levels during the warm period. Conversely, warm climates significantly enhance the respiratory carbon efflux. The finding of lower sensitivity of photosynthesis relative to that of respiration suggests that increased temperature will weaken the carbon-sink strength of East Asia subtropical evergreen forests. (letter)

Source apportionment of heavy metals and ionic contaminants in rainwater tanks in a subtropical urban area in Australia.

Science.gov (United States)

Huston, R; Chan, Y C; Chapman, H; Gardner, T; Shaw, G

2012-03-15

Due to prolonged droughts in recent years, the use of rainwater tanks in urban areas has increased in Australia. In order to apportion sources of contribution to heavy metal and ionic contaminants in rainwater tanks in Brisbane, a subtropical urban area in Australia, monthly tank water samples (24 sites, 31 tanks) and concurrent bulk deposition samples (18 sites) were collected during mainly April 2007-March 2008. The samples were analysed for acid-soluble metals, soluble anions, total inorganic carbon and total organic carbon, and characteristics such as total solid and pH. The Positive Matrix Factorisation model, EPA PMF 3.0, was used to apportion sources of contribution to the contaminants. Four source factors were identified for the bulk deposition samples, including 'crustal matter/sea salt', 'car exhausts/road side dust', 'industrial dust' and 'aged sea salt/secondary aerosols'. For the tank water samples, apart from these atmospheric deposition related factors which contributed in total to 65% of the total contaminant concentration on average, another six rainwater collection system related factors were identified, including 'plumbing', 'building material', 'galvanizing', 'roofing', 'steel' and 'lead flashing/paint' (contributing in total to 35% of the total concentration on average). The Australian Drinking Water Guideline for lead was exceeded in 15% of the tank water samples. The collection system related factors, in particular the 'lead flashing/paint' factor, contributed to 79% of the lead in the tank water samples on average. The concentration of lead in tank water was found to vary with various environmental and collection system factors, in particular the presence of lead flashing on the roof. The results also indicated the important role of sludge dynamics inside the tank on the quality of tank water. Copyright © 2011 Elsevier Ltd. All rights reserved.

Strong hydrological control on nutrient cycling of subtropical rainforests

Science.gov (United States)

Lin, T. C.; Chang, C. T.; Huang, J. C.; Wang, L.; Lin, N. H.

2016-12-01

Forest nutrient cycling is strongly controlled by both biological and hydrological factors. However, based on a close examination of earlier reports, we highlight the role of hydrological control on nutrient cycling at a global scale and is more important at humid tropical and subtropical forests. we analyzed the nutrient budget of precipitation input and stream water output from 1994 to 2013 in a subtropical forest in Taiwan and conducted a data synthesis using results from 32 forests across the globe. The results revealed that monthly input and output of ions were positively correlated with water quantity, indicating hydrological control on nutrient cycling. Hydrological control is also evident from the greater ions export via stream water during the warm and wet growing season. The synthesis also illustrates that strong hydrological control leads to lower nitrogen retention and greater net loss of base cations in humid regions, particularly in the humid tropical and subtropical forests. Our result is of great significance in an era of global climate change because climate change could directly affect ecosystem nutrient cycling particularly in the tropics through changes in patterns of precipitation regime.

Effect of interannual variation in winter vertical mixing on CH4 dynamics in a subtropical reservoir

Science.gov (United States)

Itoh, Masayuki; Kobayashi, Yuki; Chen, Tzong-Yueh; Tokida, Takeshi; Fukui, Manabu; Kojima, Hisaya; Miki, Takeshi; Tayasu, Ichiro; Shiah, Fuh-Kwo; Okuda, Noboru

2015-07-01

Although freshwaters are considered to be substantial natural sources of atmospheric methane (CH4), in situ processes of CH4 production and consumption in freshwater ecosystems are poorly understood, especially in subtropical areas, leading to uncertainties in the estimation of global CH4 emissions. To improve our understanding of physical and biogeochemical factors affecting CH4 dynamics in subtropical lakes, we examined vertical and seasonal profiles of dissolved CH4 and its carbon isotope ratio (δ13C) and conducted incubation experiments to assess CH4 production and oxidation in the deep subtropical Fei-Tsui Reservoir (FTR; Taiwan). The mixing pattern of the FTR is essentially monomixis, but the intensity of winter vertical mixing changes with climatic conditions. In years with incomplete vertical mixing (does not reach the bottom) and subsequent strong thermal stratification resulting in profundal hypoxia, we observed increases in sedimentary CH4 production and thus profundal CH4 storage with the development of reducing conditions. In contrast, in years with strong winter vertical mixing to the bottom of the reservoir, CH4 production was suppressed under NO3--rich conditions, during which denitrifiers have the competitive advantage over methanogens. Diffusive emission from profundal CH4 storage appeared to be negligible due to the efficiency of CH4 oxidation during ascent through methane-oxidizing bacteria (MOB) activity. Most of the profundal CH4 was rapidly oxidized by MOB in both oxic and anoxic layers, as characterized by its carbon isotope signature. In contrast, aerobic CH4 production in the subsurface layer, which may be enhanced under high temperatures in summer, may account for a large portion of atmospheric CH4 emissions from this reservoir. Our CH4 profiling results provide valuable information for future studies predicting CH4 emissions from subtropical lakes with the progress of global warming.

Radiation preservation of subtropical fruits in South Africa

International Nuclear Information System (INIS)

Brodrick, H.T.; Thomas, A.C.

1978-01-01

Investigations on the radiation treatment of subtropical fruits were conducted over several seasons at the Atomic Energy Board in conjunction with the Citrus and Subtropical Fruit Research Institute, Nelspruit. In the case of mangoes irradiation, in combination with hot-water or heated-fungicide treatment, by controlling fungal and insect attack, makes possible the transport of fruits to Europe by sea and, with the additional advantage od delayed ripening, a marked improvement in national distribution is also achieved. A commercial feasibility study for mango processing is summarized and a pilot-plant operation for mangoes is also described. Promising results have also been obtained with respect to disease control and delayed senescence in papayas, and similar benefits to those described for mangoes can be achieved under local-market and export conditions. In the case of litchis, although work is in an early stage, effective disease control has been obtained with irradiation treatment. With regard to avocados, a greatly reduced dose with a mild heat treatment produced delayed ripening without significant adverse effects, and resulted in a shelf-life extension of several days. The results given in the report show that the irradiation of subtropical fruits holds considerable promise in terms of reduced losses, improved fruit quality, better distribution and large-scale exports. With the possibility of international clearances within the foreseeable future, commercialization of the process should follow in due course. (author)

Nitrate source apportionment in a subtropical watershed using Bayesian model

Energy Technology Data Exchange (ETDEWEB)

Yang, Liping; Han, Jiangpei; Xue, Jianlong; Zeng, Lingzao [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Shi, Jiachun, E-mail: jcshi@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Wu, Laosheng, E-mail: laowu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Jiang, Yonghai [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012 (China)

2013-10-01

Nitrate (NO{sub 3}{sup −}) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (September 2011 to July 2012). The highest NO{sub 3}{sup −} concentration in water was in May (wet season, mean ± SD = 17.45 ± 9.50 mg L{sup −1}) and the lowest concentration occurred in December (dry season, mean ± SD = 10.54 ± 6.28 mg L{sup −1}). Nevertheless, no water sample in the study area exceeds the WHO drinking water limit of 50 mg L{sup −1} NO{sub 3}{sup −}. Four sources of NO{sub 3}{sup −} (atmospheric deposition, AD; soil N, SN; synthetic fertilizer, SF; manure and sewage, M and S) were identified using both hydrochemical characteristics [Cl{sup −}, NO{sub 3}{sup −}, HCO{sub 3}{sup −}, SO{sub 4}{sup 2−}, Ca{sup 2+}, K{sup +}, Mg{sup 2+}, Na{sup +}, dissolved oxygen (DO)] and dual isotope approach (δ{sup 15}N–NO{sub 3}{sup −} and δ{sup 18}O–NO{sub 3}{sup −}). Both chemical and isotopic characteristics indicated that denitrification was not the main N cycling process in the study area. Using a Bayesian model (stable isotope analysis in R, SIAR), the contribution of each source was apportioned. Source apportionment results showed that source contributions differed significantly between the dry and wet season, AD and M and S contributed more in December than in May. In contrast, SN and SF contributed more NO{sub 3}{sup −} to water in May than that in December. M and S and SF were the major contributors in December and May, respectively. Moreover, the shortcomings and uncertainties of SIAR were discussed to provide implications for future works. With the assessment of temporal variation and sources of NO{sub 3}{sup −}, better

High carbon dioxide uptake by subtropical forest ecosystems in the East Asian monsoon region

Science.gov (United States)

Yu, Guirui; Chen, Zhi; Piao, Shilong; Peng, Changhui; Ciais, Philippe; Wang, Qiufeng; Li, Xuanran; Zhu, Xianjin

2014-01-01

Temperate- and high-latitude forests have been shown to contribute a carbon sink in the Northern Hemisphere, but fewer studies have addressed the carbon balance of the subtropical forests. In the present study, we integrated eddy covariance observations established in the 1990s and 2000s to show that East Asian monsoon subtropical forests between 20°N and 40°N represent an average net ecosystem productivity (NEP) of 362 ± 39 g C m−2 yr−1 (mean ± 1 SE). This average forest NEP value is higher than that of Asian tropical and temperate forests and is also higher than that of forests at the same latitudes in Europe–Africa and North America. East Asian monsoon subtropical forests have comparable NEP to that of subtropical forests of the southeastern United States and intensively managed Western European forests. The total NEP of East Asian monsoon subtropical forests was estimated to be 0.72 ± 0.08 Pg C yr−1, which accounts for 8% of the global forest NEP. This result indicates that the role of subtropical forests in the current global carbon cycle cannot be ignored and that the regional distributions of the Northern Hemisphere's terrestrial carbon sinks are needed to be reevaluated. The young stand ages and high nitrogen deposition, coupled with sufficient and synchronous water and heat availability, may be the primary reasons for the high NEP of this region, and further studies are needed to quantify the contribution of each underlying factor. PMID:24639529

Genetic diversity and distribution of the ciguatera-causing dinoflagellate Gambierdiscus spp. (Dinophyceae in coastal areas of Japan.

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Tomohiro Nishimura

Full Text Available The marine epiphytic dinoflagellate genus Gambierdiscus produce toxins that cause ciguatera fish poisoning (CFP: one of the most significant seafood-borne illnesses associated with fish consumption worldwide. So far, occurrences of CFP incidents in Japan have been mainly reported in subtropical areas. A previous phylogeographic study of Japanese Gambierdiscus revealed the existence of two distinct phylotypes: Gambierdiscus sp. type 1 from subtropical and Gambierdiscus sp. type 2 from temperate areas. However, details of the genetic diversity and distribution for Japanese Gambierdiscus are still unclear, because a comprehensive investigation has not been conducted yet.A total of 248 strains were examined from samples mainly collected from western and southern coastal areas of Japan during 2006-2011. The SSU rDNA, the LSU rDNA D8-D10 and the ITS region were selected as genetic markers and phylogenetic analyses were conducted. The genetic diversity of Japanese Gambierdiscus was high since five species/phylotypes were detected: including two reported phylotypes (Gambierdiscus sp. type 1 and Gambierdiscus sp. type 2, two species of Gambierdiscus (G. australes and G. cf. yasumotoi and a hitherto unreported phylotype Gambierdiscus sp. type 3. The distributions of type 3 and G. cf. yasumotoi were restricted to the temperate and the subtropical area, respectively. On the other hand, type 1, type 2 and G. australes occurred from the subtropical to the temperate area, with a tendency that type 1 and G. australes were dominant in the subtropical area, whereas type 2 was dominant in the temperate area. By using mouse bioassay, type 1, type 3 and G. australes exhibited mouse toxicities.This study revealed a surprising diversity of Japanese Gambierdiscus and the distribution of five species/phylotypes displayed clear geographical patterns in Japanese coastal areas. The SSU rDNA and the LSU rDNA D8-D10 as genetic markers are recommended for further use.

The 2014 summer coral bleaching event in subtropical Hong Kong.

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Xie, James Y; Lau, Dickey C C; Kei, Keith; Yu, Vriko P F; Chow, Wing-Kuen; Qiu, Jian-Wen

2017-11-30

We reported a coral bleaching event that occurred in August-September 2014 in Hong Kong waters based on video transect surveys conducted at eight sites. The bleaching affected eight species of corals with different growth forms. Bleaching at seven of the eight study sites was minor, affecting only 0.4-5.2% colonies and 0.8-10.0% coral-covered area. Sharp Island East, however, suffered from a moderate level of bleaching, with 13.1% colonies and 30.1% coral-covered area affected. Examination of the government's environmental monitoring data indicated abnormal water quality conditions preceding and during the bleaching event. Follow-up field surveys of tagged colonies showed that 76% of them had fully recovered, 12% partially recovered, and 12% suffered from mortality. These results indicate that the subtropical corals of Hong Kong are not immune to bleaching, and there is a need to study their responses under climate change scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tidal influence on subtropical estuarine methane emissions

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Sturm, Katrin; Grinham, Alistair; Werner, Ursula; Yuan, Zhiguo

2014-05-01

The relatively unstudied subtropical estuaries, particularly in the Southern Hemisphere, represent an important gap in our understanding of global greenhouse gas (GHG) emissions. These systems are likely to form an important component of GHG budgets as they occupy a relatively large surface area, over 38 000 km2 in Australia. Here, we present studies conducted in the Brisbane River estuary, a representative system within the subtropical region of Queensland, Australia. This is a highly modified system typical of 80% of Australia's estuaries. Generally, these systems have undergone channel deepening and straightening for safer shipping access and these modifications have resulted in large increases in tidal reach. The Brisbane River estuary's natural tidal reach was 16 km and this is now 85 km and tidal currents influence double the surface area (9 km2 to 18 km2) in this system. Field studies were undertaken to improve understanding of the driving factors behind methane water-air fluxes. Water-air fluxes in estuaries are usually calculated with the gas exchange coefficient (k) for currents and wind as well as the concentration difference across the water-air interface. Tidal studies in the lower and middle reaches of the estuary were performed to monitor the influence of the tidal stage (a proxy for kcurrent) on methane fluxes. Results for both investigated reaches showed significantly higher methane fluxes during the transition time of tides, the time of greatest tidal currents, than during slack tide periods. At these tidal transition times with highest methane chamber fluxes, lowest methane surface water concentrations were monitored. Modelled fluxes using only wind speed (kwind) were at least one order of magnitude lower than observed from floating chambers, demonstrating that current speed was likely the driving factor of water-air fluxes. An additional study was then conducted sampling the lower, middle and upper reaches during a tidal transition period

The subtropical nutrient spiral

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Jenkins, William J.; Doney, Scott C.

2003-12-01

We present an extended series of observations and more comprehensive analysis of a tracer-based measure of new production in the Sargasso Sea near Bermuda using the 3He flux gauge technique. The estimated annually averaged nitrate flux of 0.84 ± 0.26 mol m-2 yr-1 constitutes only that nitrate physically transported to the euphotic zone, not nitrogen from biological sources (e.g., nitrogen fixation or zooplankton migration). We show that the flux estimate is quantitatively consistent with other observations, including decade timescale evolution of the 3H + 3He inventory in the main thermocline and export production estimates. However, we argue that the flux cannot be supplied in the long term by local diapycnal or isopycnal processes. These considerations lead us to propose a three-dimensional pathway whereby nutrients remineralized within the main thermocline are returned to the seasonally accessible layers within the subtropical gyre. We describe this mechanism, which we call "the nutrient spiral," as a sequence of steps where (1) nutrient-rich thermocline waters are entrained into the Gulf Stream, (2) enhanced diapycnal mixing moves nutrients upward onto lighter densities, (3) detrainment and enhanced isopycnal mixing injects these waters into the seasonally accessible layer of the gyre recirculation region, and (4) the nutrients become available to biota via eddy heaving and wintertime convection. The spiral is closed when nutrients are utilized, exported, and then remineralized within the thermocline. We present evidence regarding the characteristics of the spiral and discuss some implications of its operation within the biogeochemical cycle of the subtropical ocean.

Plant trait-species abundance relationships vary with environmental properties in subtropical forests in eastern china.

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En-Rong Yan

Full Text Available Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N and phosphorus (P contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA, leaf N concentration (LN, and total leaf area per twig size (TLA were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests.

Lead poisoning among Arab American and African American children in the Detroit metropolitan area, Michigan.

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Nriagu, Jerome; Senthamarai-Kannan, Raghavendra; Jamil, Hikmet; Fakhori, Monty; Korponic, Summer

2011-09-01

This study explored the hypothesis that acculturation is a risk factor for childhood lead poisoning in the Detroit area of Michigan. Blood lead levels (BLLs) were determined in 429 Arab American and African American children, aged 6 months to 15 years, who were receiving well-child examination in three Women, Infant, and Children (WIC) clinics in the city. Mean BLL was 3.8 ± 2.3 μg/dL (range: 1-18 μg/dL) and 3.3% of the children tested had blood lead values above the 10 μg/dL level of concern. Neither the age of the dwelling units nor ethnicity of the child was significantly associated with the BLL. Multivariable analyses instead identified a number of acculturation-related factors that are associated with elevation in blood lead including paternal education, language spoken at home (English only, English and Arabic, or Arabic only), home ownership, smoking in the home, and exposure of child to home health remedies. The difference in blood lead between Arab American children from families where Arabic only versus Arabic and English is spoken at home was found to be statistically significant. This study provides information showing that immigrant children are at heightened risk of being poisoned by lead which can be useful in identifying groups at risk of atypical exposures.

The winter diet of short-eared owls in subtropical Texas: Do southern diets provide evidence of opportunity?

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Williford, Damon; Woodin, Marc C.; Skoruppa, Mary Kay

2011-01-01

Winter diet of the Short-eared Owl (Asio flammeus) in Texas is little known. We investigated the diet of Short-eared Owls wintering in McMullen County, in subtropical Texas, by analyzing the contents of 129 pellets collected over two winters (28 November 2007 to 22 February 2008 and 11 December 2008 to 11 February 2009) and conducted a latitudinal-based comparison of published diet studies of Short-eared Owls. In southern Texas, we recovered the remains of 162 prey items, 98% of which were vertebrates. Hispid cotton rats (Sigmodon hispidus) were the most important prey species in terms of percent of total number (67%) and percent of total biomass (87%). Most (86%) Short-eared Owl diet studies (based on ≥100 pellets) have been conducted north of 35°N, with only six studies, including the present study, conducted at or south of 35°N latitude. Voles (primarily Microtus spp.) were the dominant prey in North American studies (71%), but microtines were not the dominant prey in any of the six studies conducted south of 35°N latitude. We suggest that Short-eared Owls do not specialize on microtines, as is often implied, but rather depend on rodents with cyclic populations, such as the hispid cotton rat in southern areas.

Ocean-Atmosphere CO2 Fluxes in the North Atlantic Subtropical Gyre: Association with Biochemical and Physical Factors during Spring

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Macarena Burgos

2015-08-01

Full Text Available Sea surface partial pressure of CO2 (pCO2 was measured continuously in a transect of the North Atlantic subtropical gyre between Santo Domingo, Dominican Republic (18.1° N, 68.5° W and Vigo, Spain (41.9° N, 11.8° W during spring 2011. Additional biogeochemical and physical variables measured to identify factors controlling the surface pCO2 were analyzed in discrete samples collected at 16 sites along the transect at the surface and to a depth of 200 m. Sea surface pCO2 varied between 309 and 662 μatm, and showed differences between the western and eastern subtropical gyre. The subtropical gyre acted as a net CO2 sink, with a mean flux of −5.5 ± 2.2 mmol m−2 day−1. The eastern part of the transect, close to the North Atlantic Iberian upwelling off the Galician coast, was a CO2 source with an average flux of 33.5 ± 9.0 mmol m−2 day−1. Our results highlight the importance of making more surface pCO2 observations in the area located east of the Azores Islands since air-sea CO2 fluxes there are poorly studied.

Biodiversity promotes tree growth during succession in subtropical forest.

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Martin Barrufol

Full Text Available Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems.

Terminal Restriction Fragment Length Polymorphism Analysis of Soil Bacterial Communities under Different Vegetation Types in Subtropical Area.

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Zeyan Wu

Full Text Available Soil microbes are active players in energy flow and material exchange of the forest ecosystems, but the research on the relationship between the microbial diversity and the vegetation types is less conducted, especially in the subtropical area of China. In this present study, the rhizosphere soils of evergreen broad-leaf forest (EBF, coniferous forest (CF, subalpine dwarf forest (SDF and alpine meadow (AM were chosen as test sites. Terminal-restriction fragment length polymorphisms (T-RFLP analysis was used to detect the composition and diversity of soil bacterial communities under different vegetation types in the National Natural Reserve of Wuyi Mountains. Our results revealed distinct differences in soil microbial composition under different vegetation types. Total 73 microbes were identified in soil samples of the four vegetation types, and 56, 49, 46 and 36 clones were obtained from the soils of EBF, CF, SDF and AM, respectively, and subsequently sequenced. The Actinobacteria, Fusobacterium, Bacteroidetes and Proteobacteria were the most predominant in all soil samples. The order of Shannon-Wiener index (H of all soil samples was in the order of EBF>CF>SDF>AM, whereas bacterial species richness as estimated by four restriction enzymes indicated no significant difference. Principal component analysis (PCA revealed that the soil bacterial communities' structures of EBF, CF, SDF and AM were clearly separated along the first and second principal components, which explained 62.17% and 31.58% of the total variance, respectively. The soil physical-chemical properties such as total organic carbon (TOC, total nitrogen (TN, total phosphorus (TP and total potassium (TK were positively correlated with the diversity of bacterial communities.

Environmental Life Cycle Assessment of long-term organic rice production in a Subtropical area of China

DEFF Research Database (Denmark)

Xueqing, He; Qiao, Yuhui; Liang, Long

2018-01-01

a considerable environmental impact and changing from conventional to organic rice cultivation might therefore have a potentially great impact. Meanwhile, it takes time for the organic farming systems to reach a new steady state after conversion to organic. Thus, the environmental profile of the organic products...... will change over time and it is therefore important to examine whether the difference to conventional will be reduced (and disappear) or be increased over time. The aim of the present study was therefore to assess the environmental impact of organic rice production 5 (OR5), 10 (OR10) and 15 (OR15) years since...... conversion and compare it to conventional rice (CR) in subtropical China. The life cycle assessment (LCA) method was used to assess environmental impact of rice production systems with regard to nine environmental impact categories: Non-renewable Energy Depletion (NED), Water Depletion (WD), Land Occupation...

Genome Wide Association Study for Drought, Aflatoxin Resistance, and Important Agronomic Traits of Maize Hybrids in the Sub-Tropics

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Farfan, Ivan D. Barrero; De La Fuente, Gerald N.; Murray, Seth C.; Isakeit, Thomas; Huang, Pei-Cheng; Warburton, Marilyn; Williams, Paul; Windham, Gary L.; Kolomiets, Mike

2015-01-01

The primary maize (Zea mays L.) production areas are in temperate regions throughout the world and this is where most maize breeding is focused. Important but lower yielding maize growing regions such as the sub-tropics experience unique challenges, the greatest of which are drought stress and aflatoxin contamination. Here we used a diversity panel consisting of 346 maize inbred lines originating in temperate, sub-tropical and tropical areas testcrossed to stiff-stalk line Tx714 to investigate these traits. Testcross hybrids were evaluated under irrigated and non-irrigated trials for yield, plant height, ear height, days to anthesis, days to silking and other agronomic traits. Irrigated trials were also inoculated with Aspergillus flavus and evaluated for aflatoxin content. Diverse maize testcrosses out-yielded commercial checks in most trials, which indicated the potential for genetic diversity to improve sub-tropical breeding programs. To identify genomic regions associated with yield, aflatoxin resistance and other important agronomic traits, a genome wide association analysis was performed. Using 60,000 SNPs, this study found 10 quantitative trait variants for grain yield, plant and ear height, and flowering time after stringent multiple test corrections, and after fitting different models. Three of these variants explained 5–10% of the variation in grain yield under both water conditions. Multiple identified SNPs co-localized with previously reported QTL, which narrows the possible location of causal polymorphisms. Novel significant SNPs were also identified. This study demonstrated the potential to use genome wide association studies to identify major variants of quantitative and complex traits such as yield under drought that are still segregating between elite inbred lines. PMID:25714370

Tree diversity promotes insect herbivory in subtropical forests of south-east China.

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Schuldt, Andreas; Baruffol, Martin; Böhnke, Martin; Bruelheide, Helge; Härdtle, Werner; Lang, Anne C; Nadrowski, Karin; von Oheimb, Goddert; Voigt, Winfried; Zhou, Hongzhang; Assmann, Thorsten; Fridley, Jason

2010-07-01

1.Insect herbivory can strongly affect ecosystem processes, and its relationship with plant diversity is a central topic in biodiversity-functioning research. However, very little is known about this relationship from complex ecosystems dominated by long-lived individuals, such as forests, especially over gradients of high plant diversity.2.We analysed insect herbivory on saplings of 10 tree and shrub species across 27 forest stands differing in age and tree species richness in an extraordinarily diverse subtropical forest ecosystem in China. We tested whether plant species richness significantly influences folivory in these highly diverse forests or whether other factors play a more important role at such high levels of phytodiversity.3.Leaf damage was assessed on 58 297 leaves of 1284 saplings at the end of the rainy season in 2008, together with structural and abiotic stand characteristics.4.Species-specific mean damage of leaf area ranged from 3% to 16%. Herbivory increased with plant species richness even after accounting for potentially confounding effects of stand characteristics, of which stand age-related aspects most clearly covaried with herbivory. Intraspecific density dependence or other abiotic factors did not significantly influence overall herbivory across forest stands.5.Synthesis.The positive herbivory-plant diversity relationship indicates that effects related to hypotheses of resource concentration, according to which a reduction in damage by specialized herbivores might be expected as host plant concentration decreases with increasing plant diversity, do not seem to be major determinants for overall herbivory levels in our phytodiverse subtropical forest ecosystem. We discuss the potential role of host specificity of dominant herbivores, which are often expected to show a high degree of specialization in many (sub)tropical forests. In the forest system we studied, a much higher impact of polyphagous species than traditionally assumed might

Turbulent vertical diffusivity in the sub-tropical stratosphere

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I. Pisso

2008-02-01

Full Text Available Vertical (cross-isentropic mixing is produced by small-scale turbulent processes which are still poorly understood and paramaterized in numerical models. In this work we provide estimates of local equivalent diffusion in the lower stratosphere by comparing balloon borne high-resolution measurements of chemical tracers with reconstructed mixing ratio from large ensembles of random Lagrangian backward trajectories using European Centre for Medium-range Weather Forecasts analysed winds and a chemistry-transport model (REPROBUS. We focus on a case study in subtropical latitudes using data from HIBISCUS campaign. An upper bound on the vertical diffusivity is found in this case study to be of the order of 0.5 m² s⁻¹ in the subtropical region, which is larger than the estimates at higher latitudes. The relation between diffusion and dispersion is studied by estimating Lyapunov exponents and studying their variation according to the presence of active dynamical structures.

Population expanding with the phalanx model and lineages split by environmental heterogeneity: a case study of Primula obconica in subtropical China.

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Hai-Fei Yan

Full Text Available Current and historical events have both affected the current distribution patterns and intraspecific divergence of plants. While numerous studies have focused on the Qinghai-Tibetan Plateau (QTP, the impacts of such events on the flora of subtropical China remain poorly understood. Subtropical China is famous for its highly complex topography and the limited impact from glaciation during the Pleistocene; this may have resulted in a different genetic legacy for species in this region compared to fully glaciated areas.We used plastid and nuclear DNA sequence data and distribution modeling to analyze the divergence patterns and demographic history of Primula obconica Hance, a widespread herbaceous montane species in subtropical China. The phylogenetic analysis revealed two major lineages (lineage A and lineage B, representing a west-east split into the Yunnan and Eastern groups, and the Sichuan and Central groups, respectively. The Eastern and Central groups comprised relatively new derived haplotypes. Nested Clade Analysis and Bayesian Skyline Plot analyses both indicated that P. obconica mainly experienced a gradual expansion of populations. In addition, the simulated distribution of P. obconica during the Last Glacial Maximum was slightly larger than its present-day distribution.Our results are the first to identify a west-east migration of P. obconica. The gradual expansion pattern and a larger potential distribution range in cold periods detected for P. obconica indicate that the population expansion of this species is consistent with the phalanx model. In addition, the current patterns of genetic differentiation have persisted as a result of the extensive environmental heterogeneity that exists in subtropical China.

Accuracy of LiDAR-based tree height estimation and crown recognition in a subtropical evergreen broad-leaved forest in Okinawa, Japan

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Azita Ahmad Zawawi

2015-04-01

Full Text Available Aim of study: To present an approach for estimating tree heights, stand density and crown patches using LiDAR data in a subtropical broad-leaved forest. Area of study: The study was conducted within the Yambaru subtropical evergreen broad-leaved forest, Okinawa main island, Japan. Materials and methods: A digital canopy height model (CHM was extracted from the LiDAR data for tree height estimation and a watershed segmentation method was applied for the individual crown delineation. Dominant tree canopy layers were estimated using multi-scale filtering and local maxima detection. The LiDAR estimation results were then compared to the ground inventory data and a high resolution orthophoto image for accuracy assessment. Main results: A Wilcoxon matched pair test suggests that LiDAR data is highly capable of estimating tree height in a subtropical forest (z = 4.0, p = 0.345, but has limitation to detect small understory trees and a single tree delineation. The results show that there is a statistically significant different type of crown detection from LiDAR data over forest inventory (z = 0, p = 0.043. We also found that LiDAR computation results underestimated the stand density and overestimated the crown size. Research highlights: Most studies involving crown detection and tree height estimation have focused on the analysis of plantations, boreal forests and temperate forests, and less was conducted on tropical and/or subtropical forests. Our study tested the capability of LiDAR as an effective application for analyzing a highly dense forest

Effects of growth form and functional traits on response of woody plants to clearing and fragmentation of subtropical rainforest.

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Kooyman, R M; Zanne, A E; Gallagher, R V; Cornwell, W; Rossetto, M; O'Connor, P; Parkes, E A; Catterall, C F; Laffan, S W; Lusk, C H

2013-12-01

The conservation implications of large-scale rainforest clearing and fragmentation on the persistence of functional and taxonomic diversity remain poorly understood. If traits represent adaptive strategies of plant species to particular circumstances, the expectation is that the effect of forest clearing and fragmentation will be affected by species functional traits, particularly those related to dispersal. We used species occurrence data for woody plants in 46 rainforest patches across 75,000 ha largely cleared of forest by the early 1900s to determine the combined effects of area reduction, fragmentation, and patch size on the taxonomic structure and functional diversity of subtropical rainforest. We compiled species trait values for leaf area, seed dry mass, wood density, and maximum height and calculated species niche breadths. Taxonomic structure, trait values (means, ranges), and the functional diversity of assemblages of climbing and free-standing plants in remnant patches were quantified. Larger rainforest patches had higher species richness. Species in smaller patches were taxonomically less related than species in larger patches. Free-standing plants had a high percentage of frugivore dispersed seeds; climbers had a high proportion of small wind-dispersed seeds. Connections between the patchy spatial distribution of free-standing species, larger seed sizes, and dispersal syndrome were weak. Assemblages of free-standing plants in patches showed more taxonomic and spatial structuring than climbing plants. Smaller isolated patches retained relatively high functional diversity and similar taxonomic structure to larger tracts of forest despite lower species richness. The response of woody plants to clearing and fragmentation of subtropical rainforest differed between climbers and slow-growing mature-phase forest trees but not between climbers and pioneer trees. Quantifying taxonomic structure and functional diversity provides an improved basis for

Technological feasibility studies on combination treatments for subtropical fruits

International Nuclear Information System (INIS)

Brodrick, H.T.; Linde, H.J. van der

1981-01-01

Research with subtropical fruits such as papayas and mangoes had advanced beyond the experimental stage in South Africa. This may be attributed to the potential economic benefits likely to be obtained from the combination of heat and irradiation treatments. The outcome of recent marketing trials, however, revealed several problem areas which need further investigation. Some of these problems were studied in greater detail and are reported in this presentation. The effect of time delays between hot-water and irradiation treatments on the efficacy in disease control in the fruit, has received particular attention in the investigations. Efforts have also been made to correlate these results with those obtained in fungal studies in the laboratory. These and other factors relating to the technological feasibility in the use of combined treatments for the preservation of mangoes and papayas are discussed and recommendations or guidelines for future studies are given in this paper. (author)

Characterization of Unexplored Deadwood Mycobiome in Highly Diverse Subtropical Forests Using Culture-independent Molecular Technique.

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Purahong, Witoon; Pietsch, Katherina A; Lentendu, Guillaume; Schöps, Ricardo; Bruelheide, Helge; Wirth, Christian; Buscot, François; Wubet, Tesfaye

2017-01-01

The deadwood mycobiome, also known as wood-inhabiting fungi (WIF), are among the key players in wood decomposition, having a large impact on nutrient cycling in forest soils. However, our knowledge of WIF richness and distribution patterns in different forest biomes is limited. Here, we used pyrotag sequencing of the fungal internal transcribed spacer (ITS2) region to characterize the deadwood mycobiome of two tree species with greatly different wood characteristics ( Schima superba and Pinus massoniana ) in a Chinese subtropical forest ecosystem. Specifically, we tested (i) the effects of tree species and wood quality properties on WIF OTU richness and community composition; (ii) the role of biotic and abiotic factors in shaping the WIF communities; and (iii) the relationship between WIF OTU richness, community composition and decomposition rates. Due to different wood chemical properties, we hypothesized that the WIF communities derived from the two tree species would be correlated differently with biotic and abiotic factors. Our results show that deadwood in subtropical forests harbors diverse fungal communities comprising six ecological functional groups. We found interesting colonization patterns for this subtropical biome, where Resinicium spp. were highly detected in both broadleaved and coniferous deadwood. In addition, the members of Xylariales were frequently found in Schima . The two deadwood species differed significantly in WIF OTU richness ( Pinus > Schima ) and community composition ( P < 0.001). Variations in WIF community composition of both tree species were significantly explained by wood pH and ecological factors (biotic: deadwood species, basal area and abiotic: soil pH), but the WIF communities derived from each tree species correlated differently with abiotic factors. Interestingly, we found that deadwood decomposition rate significantly correlated with WIF communities and negatively correlated with WIF OTU richness. We conclude that the

The impact of anthropogenic pollution on limnological characteristics of a subtropical highland reservoir “Lago de Guadalupe”, Mexico

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Sepulveda-Jauregui A.

2013-08-01

Full Text Available “Lago de Guadalupe” is an important freshwater ecosystem located in the northern part of the metropolitan area surrounding Mexico City, under high demographic pressure. It receives approximately 15 hm3·y-1 of untreated municipal wastewater from the surrounding municipalities. In order to develop a comparative assessment of the pollution effect over the limnological characteristics of Lago de Guadalupe, this lake was characterised from February 2006 to July 2009, and the results were compared with those obtained from a non-polluted lake “Lago el Llano” located in the same drainage area. Lago de Guadalupe was hypereutrophic with anoxic conditions throughout most of the water column. In contrast, Lago el Llano was mesotrophic with high dissolved oxygen concentrations throughout the entire water column with a clinograde profile. Both reservoirs had a monomictic mixing regime. The longitudinal zonation of physicochemical and biological variables were investigated in order to better understand the processes controlling the water quality across the reservoir during its residence time. This study shows the impact of anthropogenic pollution on the limnological characteristics of a subtropical reservoir and confirms that under adequate management schemes, namely avoiding pollution and wastewater discharges, subtropical reservoirs can be prevented from developing eutrophic conditions.

Utilization and preference rating of various subtropical pasture ...

African Journals Online (AJOL)

The percentage utilization and preference demonstrated by Bonsmara beef cows was measrued twice (December 1976 and March 1977) on 18 subtropical grasses, legumes and grass-legume mixtures under supplemental spray irrigation. Clipping before and after grazing, with a two to three day period of stay, was carried ...

Residents’ Experiences of Privacy and Comfort in Multi-Storey Apartment Dwellings in Subtropical Brisbane

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Rosemary Kennedy

2015-06-01

Full Text Available Dwellings in multi-storey apartment buildings (MSAB are predicted to increase dramatically as a proportion of housing stock in subtropical cities over coming decades. The problem of designing comfortable and healthy high-density residential environments and minimising energy consumption must be addressed urgently in subtropical cities globally. This paper explores private residents’ experiences of privacy and comfort and their perceptions of how well their apartment dwelling modulated the external environment in subtropical conditions through analysis of 636 survey responses and 24 interviews with residents of MSAB in inner urban neighbourhoods of Brisbane, Australia. The findings show that the availability of natural ventilation and outdoor private living spaces play important roles in resident perceptions of liveability in the subtropics where the climate is conducive to year round “outdoor living”. Residents valued choice with regard to climate control methods in their apartments. They overwhelmingly preferred natural ventilation to manage thermal comfort, and turned to the air-conditioner for limited periods, particularly when external conditions were too noisy. These findings provide a unique evidence base for reducing the environmental impact of MSAB and increasing the acceptability of apartment living, through incorporating residential attributes positioned around climate-responsive architecture.

Effects of forest conversion on the assemblages' structure of aquatic insects in subtropical regions

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Tiago R.N. Bertaso

2015-03-01

Full Text Available The effects of forest conversion to agricultural land uses on assemblages of aquatic insects were analyzed in subtropical streams. Organisms and environmental variables were collected in six low-order streams: three streams located in a forested area, and three in areas converted to agricultural land uses. We expected that the aquatic insects' assemblage attributes would be significantly affected by forest conversion, as well as by environmental variables. Streams in converted areas presented lower species richness, abundance and proportion of sensitive insect taxa. The ANOSIM test evidenced strong difference in EPT assemblage structure between streams of forested and converted areas. The ISA test evidenced several EPT genera with high specificity to streams in forested areas and only one genus related to streams in converted areas. Thus, the impacts of the conversion of forested area to agricultural land uses have significantly affected the EPT assemblages, while environmental variables were not affected. We suggest that the effects detected can be influenced by two processes related to vegetation cover: i lower input of allochthonous material, and ii increased input of fine sediments in streams draining converted areas.

Gooseneck barnacles (Lepas spp. ingest microplastic debris in the North Pacific Subtropical Gyre

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Miriam C. Goldstein

2013-10-01

Full Text Available Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp., which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

Dieta e uso de habitat da jararaca-do-brejo, Mastigodryas bifossatus Raddi (Serpentes, Colubridade em domínio subtropical do Brasil Diet and habitat use of swamp racer snake, Mastigodryas bifossatus Raddi (Serpentes, Colubridae in subtropical domains of Brazil

Directory of Open Access Journals (Sweden)

Pedro T. Leite

2007-01-01

Full Text Available A serpente Mastigodryas bifossatus Raddi, 1820 é um grande colubrídeo neotropical que habita áreas abertas na América do Sul. Sua dieta é composta principalmente por anfíbios, mas inclui outros itens como mamíferos e lagartos. A dissecção de 224 espécimes desta serpente, provenientes dos estados do Rio Grande do Sul, Santa Catarina e Paraná, preservados em coleções herpetológicas do Brasil e um estudo de campo entre 1996 e 1998, fornecem informações sobre os hábitos alimentares e uso de habitat dessa serpente em domínio subtropical no Brasil. Essa serpente alimenta-se de anfíbios (80%, em sua maioria da família Leptodactylidae, mamíferos (10% e lagartos (2%. Foi verificada mudança ontogenética na dieta de M. bifossatus, o tamanho das presas ingeridas aumenta com o aumento de tamanho da serpente. Essa espécie ocorre principalmente em áreas abertas, algumas vezes perto de áreas antrópicas em domínio subtropical no Brasil.Mastigodryas bifossatus Raddi, 1820 is a large neotropical colubrid snake that inhabits open areas in South America. The diet is mainly composed by frogs, but it includes other items like mammals and lizards. The dissection of 224 specimens of this snake, proceeding from the states of Rio Grande do Sul, Santa Catarina and Paraná, stored in herpetological collections in Brazil and a field study between 1996 and 1998, provided information on dietary habits and habitat use of this snake in subtropical domains in Brazil. This snake eats mainly amphibians of the family Leptodactylidae (80%, mammals (10% and lizards (2%. There is ontogenetic diet shift in M. bifossatus, as the snake grows, the range of preys grows as well. M. bifossatus occur in open areas.

Electricity use characteristics of purpose-built office buildings in subtropical climates

International Nuclear Information System (INIS)

Lam, Joseph C.; Chan, Ricky Y.C.; Tsang, C.L.; Li, Danny H.W.

2004-01-01

The electricity use characteristics of 20 air conditioned office buildings in the public sector in subtropical Hong Kong were investigated. Monthly electricity consumption data were gathered and analysed. The annual electricity use per unit gross floor area ranged from 163 to 389 kW h/m 2 , with a mean of 270 kW h/m 2 . Detailed energy audits and site surveys were conducted to obtain a breakdown of the energy use. The percentage consumption for the four major electricity end users, namely heating, ventilation and air conditioning, lighting, electrical equipment and lifts and escalators were 47.5%, 27.4%, 21.8% and 3.3%, respectively. Regression techniques were used to correlate the monthly electricity use with the design and climatic variables. This paper presents the work and discusses the energy use implications

Cropping Systems and Climate Change in Humid Subtropical Environments

Directory of Open Access Journals (Sweden)

Ixchel M. Hernandez-Ochoa

2018-02-01

Full Text Available In the future, climate change will challenge food security by threatening crop production. Humid subtropical regions play an important role in global food security, with crop rotations often including wheat (winter crop and soybean and maize (summer crops. Over the last 30 years, the humid subtropics in the Northern Hemisphere have experienced a stronger warming trend than in the Southern Hemisphere, and the trend is projected to continue throughout the mid- and end of century. Past rainfall trends range, from increases up to 4% per decade in Southeast China to −3% decadal decline in East Australia; a similar trend is projected in the future. Climate change impact studies suggest that by the middle and end of the century, wheat yields may not change, or they will increase up to 17%. Soybean yields will increase between 3% and 41%, while maize yields will increase by 30% or decline by −40%. These wide-ranging climate change impacts are partly due to the region-specific projections, but also due to different global climate models, climate change scenarios, single-model uncertainties, and cropping system assumptions, making it difficult to make conclusions from these impact studies and develop adaptation strategies. Additionally, most of the crop models used in these studies do not include major common stresses in this environment, such as heat, frost, excess water, pests, and diseases. Standard protocols and impact assessments across the humid subtropical regions are needed to understand climate change impacts and prepare for adaptation strategies.

Diameter growth of subtropical trees in Puerto Rico

Science.gov (United States)

Thomas J. Brandeis

2009-01-01

Puerto Rico’s forests consist of young, secondary stands still recovering from a long history of island-wide deforestation that largely abated in the mid-20th century. Limited knowledge about growth rates of subtropical tree species in these forests makes it difficult to accurately predict forest yield, biomass accumulation, and carbon...

Runoff and soil erosion of field plots in a subtropical mountainous region of China

Science.gov (United States)

Fang, N. F.; Wang, L.; Shi, Z. H.

2017-09-01

Anthropogenic pressure coupled with strong precipitation events and a mountainous landscape have led to serious soil erosion and associated problems in the subtropical climate zone of China. This study analyzes 1576 rainfall-runoff-soil loss events at 36 experimental plots (a total of 148 plot-years of data) under a wide range of conditions in subtropical mountainous areas of China where slope farming is commonly practiced. The plots, which have standardized dimensions, represent five common types of land use and have four different slopes. Event-based analyses show that almost half of the total rainfall caused soil erosion in the study area. The dominant factor controlling the runoff coefficient is the slope gradient rather than the land use type. The maximum soil lossfor crop plots under steep tillage (35°) is 5004 t km-2 for a single event. Among the common local crops, the average soil loss values increase in the following order: buckwheat soil loss increase in the following order: red clover soil loss is caused by a small number of extreme events. The annual average soil loss of the 44 plots ranges from 19 to 4090 t km-2 year-1. The annual soil loss of plots of different land use types decrease in the following order: bare land (1533 t km-2 year-1) > cropland (1179 t km-2 year-1) > terraced cropland (1083 t km-2 year-1) > orchard land (1020 t km-2 year-1) > grassland (762 t km-2 year-1) > terraced orchard land (297 t km-2 year-1) > forest and grassland (281 t km-2 year-1).

Active biomonitoring of a subtropical river using glutathione-S ...

African Journals Online (AJOL)

Active biomonitoring of a subtropical river using glutathione-S-transferase (GST) and heat shock proteins (HSP 70) in. Oreochromis niloticusas surrogate biomarkers of metal contamination. Victor Kurauone Muposhi1, Beaven Utete1*, Idah Sithole-Niang2 and Stanley Mukangenyama2. 1Wildlife Ecology and Conservation, ...

The efficiency of tobacco Bel-W3 and native species for ozone biomonitoring in subtropical climate, as revealed by histo-cytochemical techniques

International Nuclear Information System (INIS)

Alves, Edenise S.; Moura, Barbara B.; Pedroso, Andrea N.V.; Tresmondi, Fernanda; Domingos, Marisa

2011-01-01

We aimed to verify whether hydrogen peroxide (H 2 O 2 ) accumulation and cell death are detected early in three bioindicators of ozone (O 3 ), Nicotiana tabacum 'Bel-W3', Ipomoea nil 'Scarlet O'Hara' and Psidium guajava 'Paluma', and whether environmental factors also affect those microscopic markers. The three species were exposed to chronic levels of O 3 in a subtropical area and a histo-cytochemical technique that combines 3,3'-diaminobenzidine (DAB) with Evans blue staining was used in the assessments. The three species accumulated H 2 O 2 , but a positive correlation with O 3 concentration was only observed in N. tabacum. A positive correlation between O 3 and cellular death was also observed in N. tabacum. In I. nil and P. guajava, environmental factors were responsible for symptoms at the microscopic level, especially in P. guajava. We conclude that the most appropriate and least appropriate bioindicator plant for O 3 monitoring in the subtropics are N. tabacum 'Bel-W3' and P. guajava 'Paluma', respectively. - Highlights: → H 2 O 2 and cell death occur in response to O 3 and other stressful factors. → H 2 O 2 can be detected by DAB and cell death by Evans blue staining. → These techniques contribute for analysis of susceptible bioindicator species. → H 2 O 2 and cell death were explained by high levels of O 3 in N. tabacum 'Bel-W3'. → N. tabacum is the most appropriate plant for monitoring in subtropics. - Nicotiana tabacum 'Bel-W3' is better than native species for O 3 biomonitoring in the subtropics, as revealed by histo-cytochemical techniques.

TIGER/Line Shapefile, 2014, Series Information File for the Current American Indian/Alaska Native/Native Hawaiian Areas (AIANNH) National Shapefile

Data.gov (United States)

US Census Bureau, Department of Commerce — The American Indian/Alaska Native/Native Hawaiian (AIANNH) Areas Shapefile includes the following legal entities: federally recognized American Indian reservations...

Strong population bottleneck and repeated demographic expansions of Populus adenopoda (Salicaceae) in subtropical China.

Science.gov (United States)

Fan, Liqiang; Zheng, Honglei; Milne, Richard I; Zhang, Lei; Mao, Kangshan

2018-03-14

Glacial refugia and inter-/postglacial recolonization routes during the Quaternary of tree species in Europe and North America are well understood, but far less is known about those of tree species in subtropical eastern Asia. Thus, we have examined the phylogeographic history of Populus adenopoda (Salicaceae), one of the few poplars that naturally occur in this subtropical area. Genetic variations across the range of the species in subtropical China were surveyed using ten nuclear microsatellite loci and four chloroplast fragments (matK, trnG-psbK, psbK-psbI and ndhC-trnV). Coalescent-based analyses were used to test demographic and migration hypotheses. In addition, species distribution models (SDMs) were constructed to infer past, present and future potential distributions of the species. Thirteen chloroplast haplotypes were detected, and haplotype-rich populations were found in central and southern parts of the species' range. STRUCTURE analyses of nuclear microsatellite loci suggest obvious lineage admixture, especially in peripheral and northern populations. DIYABC analysis suggests that the species might have experienced two independent rounds of demographic expansions and a strong bottleneck in the late Quaternary. SDMs indicate that the species' range contracted during the Last Glacial Maximum (LGM), and contracted northward but expanded eastward during the Last Interglacial (LIG). Chloroplast data and SDMs suggest that P. adenopoda might have survived in multiple glacial refugia in central and southern parts of its range during the LGM. Populations of the Yunnan-Guizhou Plateau in the southern part have high chloroplast DNA diversity, but may have contributed little to the postglacial recolonization of northern and eastern parts. The three major demographic events inferred by DIYABC coincide with the initiation of the LIG, start of the LGM and end of the LGM, respectively. The species may have experienced multiple rounds of range contraction during

Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

Directory of Open Access Journals (Sweden)

Enqing Hou

Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

Soil Erosion and Nutrient Losses control by Plant Covers: Environmental Implications for a Subtropical Agroecosystem (SE Spain)

Energy Technology Data Exchange (ETDEWEB)

Rodriguez-Pleguezuelo, C. R.; Duran-Zuazo, V. H.; Martin-Peinado, F. J.; Franco-Tarifa, D.; Martinez-Raya, A.; Francia-Martinez, J. R.; Carceles-Rodriguez, B.; Arroyo-Panadero, L.; Casado, J. P.

2009-07-01

Soil erosion, in addition to causing on-site loss of topsoil and reducing the productivity of the land, brings about major off-site environmental effects such as water body pollution and eutrophication. In the Mediterranean area, this fact is especially relevant where precipitation is characterized by scarcity, torrent storms and extreme variability in space and time. To study the effects of soil erosion runoff potential pollution we installed six erosion plots on the taluses of orchard terraces where an intensive irrigated agriculture based on subtropical crops has been established. (Author)

Age and area predict patterns of species richness in pumice rafts contingent on oceanic climatic zone encountered.

Science.gov (United States)

Velasquez, Eleanor; Bryan, Scott E; Ekins, Merrick; Cook, Alex G; Hurrey, Lucy; Firn, Jennifer

2018-05-01

The theory of island biogeography predicts that area and age explain species richness patterns (or alpha diversity) in insular habitats. Using a unique natural phenomenon, pumice rafting, we measured the influence of area, age, and oceanic climate on patterns of species richness. Pumice rafts are formed simultaneously when submarine volcanoes erupt, the pumice clasts breakup irregularly, forming irregularly shaped pumice stones which while floating through the ocean are colonized by marine biota. We analyze two eruption events and more than 5,000 pumice clasts collected from 29 sites and three climatic zones. Overall, the older and larger pumice clasts held more species. Pumice clasts arriving in tropical and subtropical climates showed this same trend, where in temperate locations species richness (alpha diversity) increased with area but decreased with age. Beta diversity analysis of the communities forming on pumice clasts that arrived in different climatic zones showed that tropical and subtropical clasts transported similar communities, while species composition on temperate clasts differed significantly from both tropical and subtropical arrivals. Using these thousands of insular habitats, we find strong evidence that area and age but also climatic conditions predict the fundamental dynamics of species richness colonizing pumice clasts.

Distribution patterns of oceanic micronekton at seamounts and hydrographic fronts of the subtropical Atlantic Ocean

OpenAIRE

Diekmann, Rabea

2004-01-01

In the past the oceanic environment has often been compared with terrestrial deserts and until today relatively little is known about the ecology of the high seas. Within the present study pelagic oceanic communities of cephalopods and fish in the subtropical North Atlantic were investigated, and it was analysed at different spatial scales how these communities varied in response to physical gradients and hydrographic processes. First, the influence of the subtropical convergence zone in the ...

Influence of transient flooding on methane fluxes from subtropical pastures

Science.gov (United States)

Seasonally flooded subtropical pastures are major methane (CH4) sources, where transient flooding drives episodic and high-magnitude emissions from the underlying landscape. Understanding the mechanisms that drive these patterns is needed to better understand pasture CH4 emissions and their response...

Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

Institute of Scientific and Technical Information of China (English)

Xiaqin Luo; Min Cao; Min Zhang; Xiaoyang Song; Jieqiong Li; Akihiro Nakamura; Roger Kitching

2017-01-01

Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration.Although soil seed banks in different habitats have been reported,how soil seed banks vary with elerational gradients in different climatic zones is still unknown.This paper investigates seed density,species composition and nonconstituent species of forest soil seed banks in Yunnan Province,southwest China.Similarity between the soil seed bank and standing vegetation was also examined.We collected soil samples from sites spanning 12 elevations in tropical rain forests,subtropical evergreen broadleaved forests and subalpine coniferous forests,and transported them to a glasshouse for germination trials for species identification.The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests.Seeds of woody species dominated the soil seed banks of tropical and subtropical forests,while herbs dominated those of subalpine forests.The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests,followed by subtropical forests but were completely absent from subalpine forests.

Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

Directory of Open Access Journals (Sweden)

Xiaqin Luo

2017-10-01

Full Text Available Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration. Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density, species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broad-leaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine forests. The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.

Mercury in tropical and subtropical coastal environments

Science.gov (United States)

Costa, Monica F.; Landing, William M.; Kehrig, Helena A.; Barletta, Mário; Holmes, Christopher D.; Barrocas, Paulo R. G.; Evers, David C.; Buck, David G.; Vasconcellos, Ana Claudia; Hacon, Sandra S.; Moreira, Josino C.; Malm, Olaf

2012-01-01

Anthropogenic activities influence the biogeochemical cycles of mercury, both qualitatively and quantitatively, on a global scale from sources to sinks. Anthropogenic processes that alter the temporal and spatial patterns of sources and cycling processes are changing the impacts of mercury contamination on aquatic biota and humans. Human exposure to mercury is dominated by the consumption of fish and products from aquaculture operations. The risk to society and to ecosystems from mercury contamination is growing, and it is important to monitor these expanding risks. However, the extent and manner to which anthropogenic activities will alter mercury sources and biogeochemical cycling in tropical and sub-tropical coastal environments is poorly understood. Factors as (1) lack of reliable local/regional data; (2) rapidly changing environmental conditions; (3) governmental priorities and; (4) technical actions from supra-national institutions, are some of the obstacles to overcome in mercury cycling research and policy formulation. In the tropics and sub-tropics, research on mercury in the environment is moving from an exploratory “inventory” phase towards more process-oriented studies. Addressing biodiversity conservation and human health issues related to mercury contamination of river basins and tropical coastal environments are an integral part of paragraph 221 paragraph of the United Nations document “The Future We Want” issued in Rio de Janeiro in June 2012. PMID:22901765

Explaining the species richness of birds along a subtropical elevational gradient in the Hengduan Mountains

DEFF Research Database (Denmark)

Wu, Yongjie; Colwell, Robert K.; Rahbek, Carsten

2013-01-01

AimTo document the species richness pattern of birds in the Hengduan Mountains and to understand its causes. LocationHengduan Mountains, China. MethodsSpecies richness of 738 breeding bird species was calculated for each 100-m elevational band along a gradient from 100 to 6000m a.s.l. Climate data...... were compiled based on monthly records from 182 meteorological stations in the Hengduan Mountains from 1959 to 2004. We calculated the planimetric area, predicted richness under geometric constraints, three-year average NDVI (normalized difference vegetation index) and EVI (enhanced vegetation index...... that climatic and energy factors correlate well with the richness pattern of birds, and that on the surveyed subtropical mountain, the elevational bands with highest seasonality harbour fewer species than areas with less seasonal variation in temperature. The results, however, vary somewhat among taxonomic...

Nurse plant theory and its application in ecological restoration in lower subtropics of China

Institute of Scientific and Technical Information of China (English)

Hai Ren; Long Yang; Nan Liu

2008-01-01

Nurse plants are those that facilitate the growth and development of other plant species (target species) beneath their canopy because they offer benign microhabitats that are more favorable for seed germination and/or seedling recruitment than their surrounding envi-ronment. Nurse plants have been mainly used to restore vegetation in arid and sub-arid zones in recent years. Based on summarizing the definition of nurse plant and target plant, we review the nursing effect mechanisms, ecological factors that influence nursing effect, relationships between nurse plant and ecological restoration. This review also brings forward possible pairs of nurse and target species at lower subtropical areas. Furthermore, we provide the potential tendency in nurse plant research and application.

Wetter subtropics in a warmer world: Contrasting past and future hydrological cycles

Science.gov (United States)

Burls, Natalie J.; Fedorov, Alexey V.

2017-12-01

During the warm Miocene and Pliocene Epochs, vast subtropical regions had enough precipitation to support rich vegetation and fauna. Only with global cooling and the onset of glacial cycles some 3 Mya, toward the end of the Pliocene, did the broad patterns of arid and semiarid subtropical regions become fully developed. However, current projections of future global warming caused by CO2 rise generally suggest the intensification of dry conditions over these subtropical regions, rather than the return to a wetter state. What makes future projections different from these past warm climates? Here, we investigate this question by comparing a typical quadrupling-of-CO2 experiment with a simulation driven by sea-surface temperatures closely resembling available reconstructions for the early Pliocene. Based on these two experiments and a suite of other perturbed climate simulations, we argue that this puzzle is explained by weaker atmospheric circulation in response to the different ocean surface temperature patterns of the Pliocene, specifically reduced meridional and zonal temperature gradients. Thus, our results highlight that accurately predicting the response of the hydrological cycle to global warming requires predicting not only how global mean temperature responds to elevated CO2 forcing (climate sensitivity) but also accurately quantifying how meridional sea-surface temperature patterns will change (structural climate sensitivity).

Greenhouse design for vegetable production in subtropical climate in Taiwan

NARCIS (Netherlands)

Hemming, S.; Speetjens, S.L.; Wang, D.; Tsay, J.R.

2014-01-01

In Taiwan open field vegetable production is threatened by subtropical climatic disasters, such as high wind speeds and heavy rainfall, which can cause the destruction of whole crops. Next to that vegetable production is threatened by pests and diseases resulting a high need for pesticides.

Brood pheromone effects on colony protein supplement consumption and growth in the honey bee (Hymenoptera: Apidae) in a subtropical winter climate.

Science.gov (United States)

Pankiw, Tanya; Sagili, Ramesh R; Metz, Bradley N

2008-12-01

Fatty acid esters extractable from the surface of honey bee, Apis mellifera L. (Hymenoptera: Apidae), larvae, called brood pheromone, significantly increase rate of colony growth in the spring and summer when flowering plant pollen is available in the foraging environment. Increased colony growth rate occurs as a consequence of increased pollen intake through mechanisms such as increasing number of pollen foragers and pollen load weights returned. Here, we tested the hypothesis that addition of brood pheromone during the winter pollen dearth period of a humid subtropical climate increases rate of colony growth in colonies provisioned with a protein supplement. Experiments were conducted in late winter (9 February-9 March 2004) and mid-winter (19 January-8 February 2005). In both years, increased brood area, number of bees, and amount of protein supplement consumption were significantly greater in colonies receiving daily treatments of brood pheromone versus control colonies. Amount of extractable protein from hypopharyngeal glands measured in 2005 was significantly greater in bees from pheromone-treated colonies. These results suggest that brood pheromone may be used as a tool to stimulate colony growth in the southern subtropical areas of the United States where the package bee industry is centered and a large proportion of migratory colonies are overwintered.

Potential role of resurfacing Subtropical Underwater in ENSO evolution

Science.gov (United States)

Qu, T.; Chi, J.

2017-12-01

Results from a model of the Estimating the Circulation and Climate of the Ocean (ECCO) have shown that the resurfacing of high salinity Subtropical Underwater contributes to the sea surface salinity variability in the equatorial Pacific. On interannual time scale, this contribution can account for as much as 25% of the surface freshwater flux anomalies and is believed to play a role in ENSO evolution. Having these results in mind, this study investigates the surface salinity budget and its primary controls in the equatorial Pacific using ECCO output for the period 1993-2016. Particular attention is paid to 2014/2015 and 2015/2016. Preliminary analyses of the model results suggest that enhanced subsurface processes and in particular enhanced entrainment of Subtropical Underwater are primarily responsible for the positive sea surface salinity anomalies in the central equatorial Pacific during 2014/2015, which represents an opposite phase of El Niño. These subsurface processes weakened during 2015/2016, diretly contributing to the development of the 2015/2016 El Niño. The mechanisms controlling these subsurface processes are discussed.

The efficiency of tobacco Bel-W3 and native species for ozone biomonitoring in subtropical climate, as revealed by histo-cytochemical techniques

Energy Technology Data Exchange (ETDEWEB)

Alves, Edenise S., E-mail: ealves@ibot.sp.gov.br [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Moura, Barbara B., E-mail: bmourabio@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Pedroso, Andrea N.V., E-mail: andreanvpedroso@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Tresmondi, Fernanda, E-mail: ftresmondi@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Domingos, Marisa, E-mail: mmingos@superig.com.br [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil)

2011-12-15

We aimed to verify whether hydrogen peroxide (H{sub 2}O{sub 2}) accumulation and cell death are detected early in three bioindicators of ozone (O{sub 3}), Nicotiana tabacum 'Bel-W3', Ipomoea nil 'Scarlet O'Hara' and Psidium guajava 'Paluma', and whether environmental factors also affect those microscopic markers. The three species were exposed to chronic levels of O{sub 3} in a subtropical area and a histo-cytochemical technique that combines 3,3'-diaminobenzidine (DAB) with Evans blue staining was used in the assessments. The three species accumulated H{sub 2}O{sub 2}, but a positive correlation with O{sub 3} concentration was only observed in N. tabacum. A positive correlation between O{sub 3} and cellular death was also observed in N. tabacum. In I. nil and P. guajava, environmental factors were responsible for symptoms at the microscopic level, especially in P. guajava. We conclude that the most appropriate and least appropriate bioindicator plant for O{sub 3} monitoring in the subtropics are N. tabacum 'Bel-W3' and P. guajava 'Paluma', respectively. - Highlights: > H{sub 2}O{sub 2} and cell death occur in response to O{sub 3} and other stressful factors. > H{sub 2}O{sub 2} can be detected by DAB and cell death by Evans blue staining. > These techniques contribute for analysis of susceptible bioindicator species. > H{sub 2}O{sub 2} and cell death were explained by high levels of O{sub 3} in N. tabacum 'Bel-W3'. > N. tabacum is the most appropriate plant for monitoring in subtropics. - Nicotiana tabacum 'Bel-W3' is better than native species for O{sub 3} biomonitoring in the subtropics, as revealed by histo-cytochemical techniques.

Native American interpretation of cultural resources in the area of Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Stoffle, R.W.; Evans, M.J.; Harshbarger, C.L.

1989-03-01

This report presents the location and interpretation of Native American cultural resources on or near Yucca Mountain, Nevada. This work builds on the archaeological reconnaissance and identifications of cultural resources by the Desert Research Institute (for a summary, see Pippin and Zerga, 1983; Pippin, 1984). Interpretations provided by Native American Indian people are not intended to refute other scientific studies, such as botanical, wildlife, and archaeological studies. Rather, they provide additional hypotheses for future studies, and they provide a more complete cultural understanding of the Yucca Mountain area. Representatives of sixteen American Indian tribes identified the cultural value of these resources as part of a consultation relationship with the US Department of Energy (DOE). This interim report is to be used to review research procedures and findings regarding initial consultation with the sixteen tribes, in-depth interviews with tribal elders, and findings from the first on-site visit with representatives of the sixteen tribes. As additional information is collected, it will be reviewed separately. An annual report will integrate all findings. 44 refs., 58 figs., 2 tabs

Current status of the South African research program on the radiation preservation of subtropical fruits

International Nuclear Information System (INIS)

Thomas, A.C.; Brodrick, H.T.

1977-05-01

In July 1976, the Atomic Energy Board (AEB) entered into a Research Agreement with the International Atomic Energy Agency (IAEA). This was done at the invitation of the Agency, as part of its function of coordinating research programs and assisting in broadening the contact of scientific investigators with similar interests. The relevant AEB research project is that involving radiation preservation of subtropical fruits, which forms part of the IAEA's coordinated program on Technological and Economic Feasibility of Food Irradiation. The report describes the results of several season's research carried out at the AEB in conjunction with the Citrus and Subtropical Fruit Research Institute, Nelspruit, on the radiation treatment of subtropical fruits. A commercial feasibility study for mango processing is summarised and plans for pilot-plant operation are described. Equally promising results have been obtained with respect to disease control and delayed senescence in papayas. Disease in litchis was also markedly reduced by irradiation treatment, but work on this fruit is still at an early stage. In the case of avocados, a greatly reduced dose, with a mild heat treatment, produced delayed ripening without significant adverse effects, and results in a shelf-life extention of about six days. The results obtained show that the irradiation of subtropical fruits holds considerable promise in terms of reduced losses, better fruit quality, improved distribution and large-scale exports [af

Lack of a response of the sub-tropical rodent (Saccostomus ...

African Journals Online (AJOL)

1998-03-09

Mar 9, 1998 ... A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxyben- zoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent ...

Phytoplankton growth and microzooplankton grazing in the subtropical Northeast Atlantic.

Directory of Open Access Journals (Sweden)

Carlos Cáceres

Full Text Available Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E. Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11-1.60 d(-1, especially in the case of the large fraction. Grazing rates were also high (0.15-1.29 d(-1, suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres.

Phytoplankton Growth and Microzooplankton Grazing in the Subtropical Northeast Atlantic

Science.gov (United States)

Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo

2013-01-01

Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2–5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11–1.60 d−1), especially in the case of the large fraction. Grazing rates were also high (0.15–1.29 d−1), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres. PMID:23935946

An annotated list of the flora of the Bisley Area Luquillo Experimental Forest, Puerto Rico 1987 to 1992

Science.gov (United States)

Jesus Danilo Chinea; Renee J. Beymer; Carlos Rivera; Ines Sastre de Jeses; F.N. Scatena

1993-01-01

Known species of plants, including bryophytes and ferns, are listed for the area of the Bisley experimental watershed area, a subtropical wet forest in the Luquillo Mountains of northeastern Puerto Rico.

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

Science.gov (United States)

Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

2011-01-01

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr-1. NEP will increase to about 5 Mt C yr-1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little

Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

Science.gov (United States)

Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

2005-01-01

The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

Influence of Subtropical Jetstream on Arabian Gulf Precipitation

Science.gov (United States)

Sandeep, S.; Pauluis, O.; Ravindran, A. M.; TP, S.

2017-12-01

The Arabian Gulf and surrounding regions are predominantly arid. However, this region hosts a large population due to the intense economic activity that is centered on the exploration of natural resources in and around the Arabian Gulf. Thus, few precipitation events that occur during boreal winter are important for society and ecology of this region. The mechanisms of winter precipitation over the Gulf are not well understood, partly due to a lack of long term meteorological observation. Here we explore the dynamics of Arabian Gulf winter precipitation events using available observations and a high resolution atmospheric model simulation. Our analyses show that the northern Gulf receives about six times more precipitation than the southern Gulf. Often, the southern Gulf precipitation forms as a result of downstream development of northern Gulf disturbance. The southward movement of northern Gulf disturbances is influenced by the location of subtropical jet. The probability of a northern Gulf precipitating weather system to move south is higher when the subtropical jet is located equatorward of 30°N. The equatorward position of jet favors the penetration of mid-latitude weather systems over the Arabian Peninsula, which in turn pushes the Arabian anticyclone eastward and triggers moisture transport from the Arabian Sea that is essential for southern Gulf precipitation events.

Subtropical and Polar Cirrus Clouds Characterized by Ground-Based Lidars and CALIPSO/CALIOP Observations

Directory of Open Access Journals (Sweden)

Córdoba-Jabonero Carmen

2016-01-01

Full Text Available Cirrus clouds are product of weather processes, and then their occurrence and macrophysical/optical properties can vary significantly over different regions of the world. Lidars can provide height-resolved measurements with a relatively good both vertical and temporal resolutions, making them the most suitable instrumentation for high-cloud observations. The aim of this work is to show the potential of lidar observations on Cirrus clouds detection in combination with a recently proposed methodology to retrieve the Cirrus clouds macrophysical and optical features. In this sense, a few case studies of cirrus clouds observed at both subtropical and polar latitudes are examined and compared to CALIPSO/CALIOP observations. Lidar measurements are carried out in two stations: the Metropolitan city of Sao Paulo (MSP, Brazil, 23.3°S 46.4°W, located at subtropical latitudes, and the Belgrano II base (BEL, Argentina, 78ºS 35ºW in the Antarctic continent. Optical (COD-cloud optical depth and LR-Lidar Ratio and macrophysical (top/base heights and thickness properties of both the subtropical and polar cirrus clouds are reported. In general, subtropical Cirrus clouds present lower LR values and are found at higher altitudes than those detected at polar latitudes. In general, Cirrus clouds are detected at similar altitudes by CALIOP. However, a poor agreement is achieved in the LR retrieved between ground-based lidars and space-borne CALIOP measurements, likely due to the use of a fixed (or low-variable LR value in CALIOP inversion procedures.

Vegetation description and phytoclimatic gradients of subtropical forests of nandiar khuwar catchment district battagram

International Nuclear Information System (INIS)

Haq, F.; Iqbal, Z.; Ahmad, H.

2015-01-01

This paper communicates an analytical exploration of the vegetational profile in the subtropical zone of Nandiar Khuwar catchment area, District Battagrtam, Pakistan. On the basis of physiognomy of vegetation the study area was divided into 16 stands. Six plant communities were recognized by TWINSPAN classification. Among biological spectrum nanophanerophytes was dominated with 36 species and leaf size spectra were dominated by microphyll contributing 63 species. Similarity index was maximum (33.61) between Pinus, Micromeria, Rubus community and Pinus, Rubus, Cynodon community. In Bray-Curtis ordination the maximum ordination scores were recorded for axis 2 (0.921). The gradient length was maximum (3.35) for axis 1 with eigenvalue 0.50. Total variance (inertia) in the species data were 2.92, explanatory variables account for 100%. Among environmental variables the maximum positive strength were recorded for altitude (0.818) and Phosphorous (0.801) while maximum negative strength were recorded for wind speed (-0.864), barometric pressure (-0.825) and temperature (-0.820). (author)

Multi-scale forcing and the formation of subtropical desert and monsoon

Directory of Open Access Journals (Sweden)

G. X. Wu

2009-09-01

Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows. First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west. The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are located over the western

Multi-scale forcing and the formation of subtropical desert and monsoon

Directory of Open Access Journals (Sweden)

G. X. Wu

2009-09-01

Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows.

First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west.

The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are

CSFRI symposium: research into citrus and subtropical crops

International Nuclear Information System (INIS)

1986-10-01

This publication only contains the abstracts of papers delivered on the Citrus and Subtropical Fruit Research Institute symposium which was held at Nelspruit on 21-23 October 1986. The abstracts primarily discuss the problems in and around the South African fruit industry such as pest control, etiology, plant diseases, problems with greening, flowering, and plant growth. One abstract specifically discusses the effect of gamma radiation on the reproductive potential of false cadling moth

Modeling the drift of massive icebergs to the subtropical North Atlantic

Science.gov (United States)

Condron, A.; Hill, J. C.

2013-12-01

New evidence from high-resolution seafloor bathymetry data indicates that massive (>300m thick) icebergs from the Laurentide Ice Sheet (LIS) drifted south to the tip of Florida during the last deglaciation. This finding is particularly exciting as it contradicts evidence from marine sediments that icebergs were mainly confined to the subpolar North Atlantic (50 - 70N) at this time. Indeed, the freshwater released from icebergs melting in the subpolar gyre is repeatedly cited as a main trigger for a slow-down of the Atlantic MOC in the past, and the possible cause of any climate cooling related to the melting of the Greenland Ice Sheet in the future. Using a sophisticated iceberg model (MITberg), coupled to a high (18-km; 1/6 deg.) resolution ocean model (MITgcm), we investigate the ocean circulation dynamics required to allow icebergs to drift to the southern tip of Florida. We find that icebergs only reach this location if they turn right at the Grand Banks of Newfoundland, and stay inshore of the Gulf Stream all the way to Florida. Modern-day circulation dynamics do not readily allow this to happen as cold, southward flowing, Labrador Current Water (important for iceberg survival) has little penetration south of Cape Hatteras. However, when a liquid meltwater flood is released from Hudson Bay at the same time, icebergs are rapidly transported (inshore of the Gulf Stream) in a narrow, buoyant, coastal current all the way to southern Florida. The meltwater and icebergs result in a significant freshening of the subtropical North Atlantic and weaken the strength of the Gulf Stream, suggesting such an event would have a large cooling effect on climate. We are only able to simulate the flow of meltwater and icebergs to the subtropics by modeling ocean circulation at a resolution that is 5 - 10 times higher than the majority of existing paleoclimate models; at lower resolutions the narrow, coastal boundary currents important for iceberg transport to the subtropics are

Alkaline phosphatase activity in the subtropical ocean: insights from nutrient, dust and trace metal addition experiments

Directory of Open Access Journals (Sweden)

Claire eMahaffey

2014-12-01

Full Text Available Phosphorus is an essential nutrient for all life on earth. In the ocean, the most bioavailable form of phosphorus is inorganic phosphate, but in the extensive subtropical gyres, phosphate concentrations can be chronically low and limit primary productivity and nitrogen fixation. In these regions, organisms produce hydrolytic enzymes, such as alkaline phosphatase (AP, that enable them to utilize the more replete dissolved organic phosphorus (DOP pool to meet their cellular phosphorus demands. In this study, we synthesized data from 14 published studies and present our own findings from two research cruises (D326 and D361 in the eastern subtropical Atlantic to explore the relationship between AP activity (APA and nutrients, Saharan dust and trace metals. We found that below a threshold phosphate concentration of ~ 30 nM, APA increased with an inverse hyperbolic relationship with phosphate concentration. Meanwhile, DOP concentrations decreased with enhanced APA, indicating utilization of the DOP pool. We found APA rates were significantly higher in the subtropical Atlantic compared to the subtropical Pacific Ocean, even over the same low phosphate concentration range (0 to 50 nM. While the phosphate concentration may have a first order control on the APA rates, we speculate that other factors influence this basin scale contrast. Using bioassay experiments, we show that the addition of Saharan dust and zinc significantly increased the rate of APA. To our knowledge, our results are the first direct field-based evidence that APA is limited by zinc in the subtropical ocean. Further work is required to explore the relationship between trace metals such as iron and zinc, which are co-factors of phosphohydrolytic enzymes, specifically PhoX and PhoA, respectively, and APA in the ocean.

Characteristics of radon and thoron exhalation rates in Okinawa, subtropical region of Japan

International Nuclear Information System (INIS)

Shiroma, Y.; Kina, S.; Fujitani, T.; Hosoda, M.; Sorimachi, A.; Ishikawa, T.; Sahoo, S. K.; Tokonami, S.; Furukawa, M.

2012-01-01

Radon and thoron exhalation rates from the ground surface were estimated in three islands of Okinawa Prefecture, a subtropical region of Japan. In situ measurements of the exhalation rates were conducted at a total of 88 points using an accumulation technique with a ZnS(Ag) scintillation detector. The radon and thoron exhalation rates were calculated to be 1-137(arithmetic mean: 21) mBq m -2 s -1 and 32-6244 (1801) mBq m -2 s -1 , respectively. In the surface soil samples collected at 53 measurement points, 238 U and 232 Th series concentrations were estimated to be 17.9-254.0 (64.0) Bq kg -1 dry and 17.8-136.1 (58.8) Bq kg -1 dry, respectively. The maximum rates and concentrations were observed in the dark red soil area. Recent studies strongly suggest that the base material of the soils may be the eolian dust derived from the southeastern part of China, a high background radiation area. The eolian dust is, therefore, considered to be an enhancer for the radon and thoron exhalations in Okinawa. (authors)

Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. I. Phytoplankton and bacterioplankton

DEFF Research Database (Denmark)

Riemann, Lasse; Nielsen, Torkel Gissel; Kragh, Theis

2011-01-01

Elevated levels of biomass and productivity are often associated with ocean frontal systems. The Subtropical Convergence Zone (STCZ) in the southern Sargasso Sea shows pronounced and stable thermal fronts, but little is known about the ecological consequences of these hydrographic features....... With the aim of improving the understanding of physical and lower trophic level processes in the area, we carried out field studies of physical, chemical and biological characteristics along 3 transects crossing thermal fronts associated with the STCZ in March to April 2007. Thermal and chemical stratification...

Lysogenic infection in sub-tropical freshwater cyanobacteria cultures and natural blooms

NARCIS (Netherlands)

Steenhauer, L.M.; Pollard, P.C.; Brussaard, C.P.D.; Säwström, C.

2014-01-01

Lysogeny has been reported for a few freshwater cyanobacteria cultures, but it is unknown how prevalent it is in freshwater cyanobacteria in situ. Here we tested for lysogeny in (a) cultures of eight Australian species of subtropical freshwater cyanobacteria; (b) seven strains of one species:

Linking The Atlantic Gyres: Warm, Saline Intrusions From Subtropical Atlantic to the Nordic Seas

Science.gov (United States)

Hakkinen, Sirpa M.; Rhines, P. B.

2010-01-01

Ocean state estimates from SODA assimilation are analyzed to understand how major shifts in the North Atlantic Current path relate to AMOC, and how these shifts are related to large scale ocean circulation and surface forcing. These complement surface-drifter and altimetry data showing the same events. SODA data indicate that the warm water limb of AMOC, reaching to at least 600m depth, expanded in density/salinity space greatly after 1995, and that Similar events occurred in the late 1960s and around 1980. While there were large changes in the upper limb, there was no immediate response in the dense return flow, at least not in SODA, however one would expect a delayed response of increasing AMOC due to the positive feedback from increased salt transport. These upper limb changes are winddriven, involving changes in the eastern subpolar gyre, visible in the subduction of low potential vorticity waters. The subtropical gyre has been weak during the times of the northward intrusions of the highly saline subtropical waters, while the NAO index has been neutral or in a negative phase. The image of subtropical/subpolar gyre exchange through teleconnections within the AMOC overturning cell will be described.

Manure management in the (Sub-)Tropics : training manual for extension workers

NARCIS (Netherlands)

Teenstra, E.D.; Buisonjé, de F.E.; Ndambi, A.; Pelster, D.

2015-01-01

Having identified a general lack of knowledge about the value of livestock manure and integrated manure management at multiple levels in government and society, a concerted action led to the compilation of a training manual for extension workers on manure management in the (sub-)tropics. Covering

Intra- and interspecific trait variations reveal functional relationships between specific leaf area and soil niche within a subtropical forest.

Science.gov (United States)

He, Dong; Chen, Yongfa; Zhao, Kangning; Cornelissen, J H C; Chu, Chengjin

2018-02-03

How functional traits vary with environmental conditions is of fundamental importance in trait-based community ecology. However, how intraspecific variability in functional traits is connected to species distribution is not well understood. This study investigated inter- and intraspecific variation of a key functional trait, i.e. specific leaf area (leaf area per unit dry mass; SLA), in relation to soil factors and tested if trait variation is more closely associated with specific environmental regimes for low-variability species than for high-variability species. In a subtropical evergreen forest plot (50 ha, southern China), 106 700 leaves from 5335 individuals of 207 woody species were intensively collected, with 30 individuals sampled for most species to ensure a sufficient sample size representative of intraspecific variability. Soil conditions for each plant were estimated by kriging from more than 1700 observational soil locations across the plot. Intra- and interspecific variation in SLA were separately related to environmental factors. Based on the species-specific variation of SLA, species were categorized into three groups: low-, intermediate- and high-intraspecific variability. Intraspecific habitat ranges and the strength of SLA-habitat relationships were compared among these three groups. Interspecific variation in SLA overrides the intraspecific variation (77 % vs. 8 %). Total soil nitrogen (TN, positively) and total organic carbon (TOC, negatively) are the most important explanatory factors for SLA variation at both intra- and interspecific levels. SLA, both within and between species, decreases with decreasing soil nitrogen availability. As predicted, species with low intraspecific variability in SLA have narrower habitat ranges with respect to soil TOC and TN and show a stronger SLA-habitat association than high-variability species. For woody plants low SLA is a phenotypic and probably adaptive response to nitrogen stress, which drives the

Iodine monoxide in the north subtropical free troposphere

OpenAIRE

O. Puentedura; M. Gil; A. Saiz-Lopez; T. Hay; M. Navarro-Comas; A. Gómez-Pelaez; E. Cuevas; J. Iglesias; L. Gomez

2012-01-01

Iodine monoxide (IO) differential slant column densities (DSCD) have been retrieved from a new multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument deployed at the Izaña subtropical observatory as part of the Network for the Detection of Atmospheric Composition Change (NDACC) programme. The station is located at 2370 m a.s.l., well above the trade wind inversion that limits the top of the marine boundary layer, and hence is representative of the free troposphere. We r...

Extreme weather: Subtropical floods and tropical cyclones

Science.gov (United States)

Shaevitz, Daniel A.

Extreme weather events have a large effect on society. As such, it is important to understand these events and to project how they may change in a future, warmer climate. The aim of this thesis is to develop a deeper understanding of two types of extreme weather events: subtropical floods and tropical cyclones (TCs). In the subtropics, the latitude is high enough that quasi-geostrophic dynamics are at least qualitatively relevant, while low enough that moisture may be abundant and convection strong. Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent, and large latent heat release. In the first part of this thesis, I examine the possible triggering of convection by the large-scale dynamics and investigate the coupling between the two. Specifically two examples of extreme precipitation events in the subtropics are analyzed, the 2010 and 2014 floods of India and Pakistan and the 2015 flood of Texas and Oklahoma. I invert the quasi-geostrophic omega equation to decompose the large-scale vertical motion profile to components due to synoptic forcing and diabatic heating. Additionally, I present model results from within the Column Quasi-Geostrophic framework. A single column model and cloud-revolving model are forced with the large-scale forcings (other than large-scale vertical motion) computed from the quasi-geostrophic omega equation with input data from a reanalysis data set, and the large-scale vertical motion is diagnosed interactively with the simulated convection. It is found that convection was triggered primarily by mechanically forced orographic ascent over the Himalayas during the India/Pakistan flood and by upper-level Potential Vorticity disturbances during the Texas/Oklahoma flood. Furthermore, a climate attribution analysis was conducted for the Texas/Oklahoma flood and it is found that anthropogenic climate change was responsible for a small amount of rainfall during the event but the

Experimental evidence for a phylogenetic Janzen-Connell effect in a subtropical forest

NARCIS (Netherlands)

Liu, Xubing; Liang, Minxia; Etienne, Rampal S.; Wang, Yongfan; Staehelin, Christian; Yu, Shixiao

Observational evidence increasingly suggests that the JanzenConnell effect extends beyond the species boundary. However, this has not been confirmed experimentally. Herein, we present both observational and experimental evidence for a phylogenetic JanzenConnell effect. In a subtropical forest in

Distribution of functional traits in subtropical trees across environmental and forest use gradients

Science.gov (United States)

Blundo, Cecilia; Malizia, Lucio R.; González-Espinosa, Mario

2015-11-01

The relationship between functional traits and environmental factors contribute to understanding community structure and predicting which species will be able to elude environmental filters in different habitats. We selected 10 functional traits related to morphology, demography and regeneration niche in 54 subtropical premontane tree species to describe their main axes of functional differentiation. We derived species traits, environmental variables and species abundance data from 20 1-ha permanent plots established in a seasonal subtropical premontane forest in northwestern Argentina. We analyzed the relationship between species functional traits and environmental factors through RLQ and fourth-corner analyzes. We found an axis of structural differentiation that segregates understory from canopy species, and an axis of functional differentiation that segregates species that maximize resource acquisition from those that promote resource conservation. Environmental and forest use gradients operate hierarchically over subtropical premontane tree species influencing the distribution of demographic and morphological traits. The interaction between climatic and topographic factors influences the distribution of species functional traits at the regional scale. In addition, the history of forest use seems to operate at the landscape scale and explains the distribution of species traits reflecting a trade-off between resource acquisition and resource conservation strategies in secondary forests across different successional stages. Our results support the idea that functional traits may be used to analyze community structure and dynamics through niche differentiation and environmental filtering processes.

Depositional history of sedimentary linear alkylbenzenes (LABs) in a large South American industrial coastal area (Santos Estuary, Southeastern Brazil)

International Nuclear Information System (INIS)

Martins, Cesar C.; Bicego, Marcia C.; Mahiques, Michel M.; Figueira, Rubens C.L.; Tessler, Moyses G.; Montone, Rosalinda C.

2010-01-01

This paper reports the reconstruction of the contamination history of a large South American industrial coastal area (Santos Estuary, Brazil) using linear alkylbenzenes (LABs). Three sediment cores were dated by 137 Cs. Concentrations in surficial layers were comparable to the midrange concentrations reported for coastal sediments worldwide. LAB concentrations increased towards the surface, indicating increased waste discharges into the estuary in recent decades. The highest concentration values occurred in the early 1970s, a time of intense industrial activity and marked population growth. The decreased LAB concentration, in the late 1970s was assumed to be the result of the world oil crisis. Treatment of industrial effluents, which began in 1984, was represented by decreased LAB levels. Microbial degradation of LABs may be more intense in the industrial area sediments. The results show that industrial and domestic waste discharges are a historical problem in the area. - The contamination history of a large South American industrial coastal area indicated by molecular indicator of sewage input.

Nutrient leaching under zero tension in a subtropical clonal eucalypt ...

African Journals Online (AJOL)

Little is known about the effects of residue burning or retention on nutrient leaching during the inter-rotation of clonal Eucalyptus grown on the sandy soils of subtropical Zululand, South Africa. A study compared zero-tension nutrient leaching through the top metre of soil at depths of 0.15, 0.5 and 1.0 m in an undisturbed crop ...

The structuring role of submerged macrophytes in a large subtropical shallow lake

NARCIS (Netherlands)

Finkler Ferreira, Tiago; Crossetti, Luciane O.; Motta Marques, David M.L.; Cardoso, Luciana; Fragoso, Carlos Ruberto; Nes, van Egbert H.

2018-01-01

It is well known that submerged macrophytes exert positive feedback effects that enhance the water transparency, stabilizing the clear-water state in shallow temperate lakes. However, the structuring effect of macrophytes on the food web of subtropical and tropical ecosystems is still poorly

Identifying role of subtropical southeast Pacific SST anomalies on precipitation dynamics in Central Chile

Science.gov (United States)

Bozkurt, D.; Garreaud, R.

2014-12-01

Central Chile (CC, western South America coasts, 28°S- 38°S) is the heartland of Chile with the highest population and important economic activities. The region is characterized by semiarid Mediterranean climate with a marked precipitation gradient along the coast from north to south, mostly due to the positioning of the South Pacific Subtropical Anticyclone and the midlatitude westerlies belt. Although there are several diagnostic studies that focus on the impact of tropical Pacific SST on CC precipitation variability via atmospheric teleconnections, less attention has been placed on impacts of subtropical southeast (SE) Pacific SST on precipitation. The later region is immediately adjacent to CC and it interferes with the overpassing atmospheric systems. In particular we want to assess the impact of a consistent cooling over the SE Pacific during the last 30 years. This study is being tackled by a combination of observational and reanalysis datasets together with numerical simulations. Observational dataset includes gridded dataset of CRU, TRMM and GPCP. Moreover, Reynolds SST data V2 based on AVHRR infrared satellite SST data is used for analyzing spatial and temporal changes in SST. Current modelling experiment includes a control simulation, used as reference, and sensitivity simulation that involves perturbations to SST over subtropical SE Pacific for a normal year austral winter (2001) season. A number of simulations with different initial conditions have been carried out by employing ICTP-RegCM4. The domain for simulations was centered at 82oW and 32oW with 288x288 grid cells on 20 km spatial resolution. Preliminary results indicate that the response of precipitation in CC to SST anomalies in the subtropical SE Pacific exhibits more or less linear behavior. In the colder SST experiments, drier conditions dominate over CC, which is possibly related with the intensification of South Pacific Subtropical Anticyclone (SPSA) or a reduction in the available

Reciprocal experimental transplantations to assess effects of organic enrichment on the recolonization of benthic macrofauna in a subtropical estuary.

Science.gov (United States)

Gern, Fabiana Regina; Lana, Paulo da Cunha

2013-02-15

Coastal benthic habitats are usually in a state of continuous recolonization as a consequence of natural disturbances or human activities. Recolonization patterns can be strongly affected by the quality of the sediment. We evaluated herein the macrobenthic recolonization of organically enriched sediments through a manipulative experiment involving reciprocal transplants between contaminated and non-contaminated intertidal areas. Regardless of the experimental treatments, the density of the polychaete Capitella sp. was extremely high in the contaminated area as well as the density of the gastropod Cylichna sp. in the non-contaminated area. We rejected the hypothesis that differences in sediment quality would determine macrofaunal recolonization at least in the considered scales of space in meters and time in weeks. The recolonization process in a subtropical estuarine environment was strongly dependent on the migration of adults present in the sediments adjacent to the experimental units. Copyright © 2012 Elsevier Ltd. All rights reserved.

A synthesis of the environmental response of the North and South Atlantic Sub-Tropical Gyres during two decades of AMT

Science.gov (United States)

Aiken, Jim; Brewin, Robert J. W.; Dufois, Francois; Polimene, Luca; Hardman-Mountford, Nick J.; Jackson, Thomas; Loveday, Ben; Hoya, Silvana Mallor; Dall'Olmo, Giorgio; Stephens, John; Hirata, Takafumi

2017-11-01

Anthropogenically-induced global warming is expected to decrease primary productivity in the subtropical oceans by strengthening stratification of the water column and reducing the flux of nutrients from deep-waters to the sunlit surface layers. Identification of such changes is hindered by a paucity of long-term, spatially-resolved, biological time-series data at the basin scale. This paper exploits Atlantic Meridional Transect (AMT) data on physical and biogeochemical properties (1995-2014) in synergy with a wide range of remote-sensing (RS) observations from ocean colour, Sea Surface Temperature (SST), Sea Surface Salinity (SSS) and altimetry (surface currents), combined with different modelling approaches (both empirical and a coupled 1-D Ecosystem model), to produce a synthesis of the seasonal functioning of the North and South Atlantic Sub-Tropical Gyres (STGs), and assess their response to longer-term changes in climate. We explore definitive characteristics of the STGs using data of physical (SST, SSS and peripheral current systems) and biogeochemical variables (chlorophyll and nitrate), with inherent criteria (permanent thermal stratification and oligotrophy), and define the gyre boundary from a sharp gradient in these physical and biogeochemical properties. From RS data, the seasonal cycles for the period 1998-2012 show significant relationships between physical properties (SST and PAR) and gyre area. In contrast to expectations, the surface layer chlorophyll concentration from RS data (CHL) shows an upward trend for the mean values in both subtropical gyres. Furthermore, trends in physical properties (SST, PAR, gyre area) differ between the North and South STGs, suggesting the processes responsible for an upward trend in CHL may vary between gyres. There are significant anomalies in CHL and SST that are associated with El Niño events. These conclusions are drawn cautiously considering the short length of the time-series (1998-2012), emphasising the need

Ecophysiological and anatomical characteristics of the subtropical shrub Zanthoxylum acanthopodium (Rutaceae) in conditions of a temperate continental climate (Serbia)

DEFF Research Database (Denmark)

Rakic, Tamara; Sinzar-Sekulic, Jasmina; Filipovic, Biljana

2009-01-01

The evergreen shrub Zanthoxylum acanthopodium DC. (Rutaceae), originating from warm temperate and subtropical Asia, has existed successfully in the Jevremovac Botanical Garden in Belgrade for more than 80 years. The seasonal pattern of water management in leaves, electrolyte leakage, essential oil...... composition, and leaf anatomy were examined in order to understand the resistance and viability of this subtropical shrub in the temperate continental climate of Belgrade, Serbia....

Grasslands feeling the heat: The effects of elevated temperatures on a subtropical grassland

Directory of Open Access Journals (Sweden)

Rowan D. Buhrmann

2016-12-01

Conclusions: OTCs can simulate realistic increases of air temperature in subtropical grasslands. Graminoids and shrubs appear to benefit from elevated temperatures whilst forbs decrease in abundance, possibly through competition and/or direct physiological effects.

Perfluoroalkylated substances in the global tropical and subtropical surface oceans.

Science.gov (United States)

González-Gaya, Belén; Dachs, Jordi; Roscales, Jose L; Caballero, Gemma; Jiménez, Begoña

2014-11-18

In this study, perfluoroalkylated substances (PFASs) were analyzed in 92 surface seawater samples taken during the Malaspina 2010 expedition which covered all the tropical and subtropical Atlantic, Pacific and Indian oceans. Nine ionic PFASs including C6-C10 perfluoroalkyl carboxylic acids (PFCAs), C4 and C6-C8 perfluoroalkyl sulfonic acids (PFSAs) and two neutral precursors perfluoroalkyl sulfonamides (PFASAs), were identified and quantified. The Atlantic Ocean presented the broader range in concentrations of total PFASs (131-10900 pg/L, median 645 pg/L, n = 45) compared to the other oceanic basins, probably due to a better spatial coverage. Total concentrations in the Pacific ranged from 344 to 2500 pg/L (median = 527 pg/L, n = 27) and in the Indian Ocean from 176 to 1976 pg/L (median = 329, n = 18). Perfluorooctanesulfonic acid (PFOS) was the most abundant compound, accounting for 33% of the total PFASs globally, followed by perfluorodecanoic acid (PFDA, 22%) and perfluorohexanoic acid (PFHxA, 12%), being the rest of the individual congeners under 10% of total PFASs, even for perfluorooctane carboxylic acid (PFOA, 6%). PFASAs accounted for less than 1% of the total PFASs concentration. This study reports the ubiquitous occurrence of PFCAs, PFSAs, and PFASAs in the global ocean, being the first attempt, to our knowledge, to show a comprehensive assessment in surface water samples collected in a single oceanic expedition covering tropical and subtropical oceans. The potential factors affecting their distribution patterns were assessed including the distance to coastal regions, oceanic subtropical gyres, currents and biogeochemical processes. Field evidence of biogeochemical controls on the occurrence of PFASs was tentatively assessed considering environmental variables (solar radiation, temperature, chlorophyll a concentrations among others), and these showed significant correlations with some PFASs, but explaining small to moderate percentages of variability

Coherent mesoscale eddies in the North Atlantic subtropical gyre: 3-D structure and transport with application to the salinity maximum

Science.gov (United States)

Amores, Angel; Melnichenko, Oleg; Maximenko, Nikolai

2017-01-01

The mean vertical structure and transport properties of mesoscale eddies are investigated in the North Atlantic subtropical gyre by combining historical records of Argo temperature/salinity profiles and satellite sea level anomaly data in the framework of the eddy tracking technique. The study area is characterized by a low eddy kinetic energy and sea surface salinity maximum. Although eddies have a relatively weak signal at surface (amplitudes around 3-7 cm), the eddy composites reveal a clear deep signal that penetrates down to at least 1200 m depth. The analysis also reveals that the vertical structure of the eddy composites is strongly affected by the background stratification. The horizontal patterns of temperature/salinity anomalies can be reconstructed by a linear combination of a monopole, related to the elevation/depression of the isopycnals in the eddy core, and a dipole, associated with the horizontal advection of the background gradient by the eddy rotation. A common feature of all the eddy composites reconstructed is the phase coherence between the eddy temperature/salinity and velocity anomalies in the upper ˜300 m layer, resulting in the transient eddy transports of heat and salt. As an application, a box model of the near-surface layer is used to estimate the role of mesoscale eddies in maintaining a quasi-steady state distribution of salinity in the North Atlantic subtropical salinity maximum. The results show that mesoscale eddies are able to provide between 4 and 21% of the salt flux out of the area required to compensate for the local excess of evaporation over precipitation.

Carbon cycling and exports over diel and flood-recovery timescales in a subtropical rainforest headwater stream

Energy Technology Data Exchange (ETDEWEB)

Looman, Arún, E-mail: arun.looman@scu.edu.au [National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales (Australia); School of Environment, Science, and Engineering, Southern Cross University, Lismore, New South Wales (Australia); Santos, Isaac R.; Tait, Douglas R.; Webb, Jackie R. [National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales (Australia); School of Environment, Science, and Engineering, Southern Cross University, Lismore, New South Wales (Australia); Sullivan, Caroline A.; Maher, Damien T. [School of Environment, Science, and Engineering, Southern Cross University, Lismore, New South Wales (Australia)

2016-04-15

Catchment headwaters comprise the majority of all stream length globally, however, carbon (C) dynamics in these systems remains poorly understood. We combined continuous measurements of pCO{sub 2} and radon ({sup 222}Rn, a natural groundwater tracer) with discrete sampling for particulate organic, dissolved organic and inorganic carbon (POC, DOC, and DIC) to assess the short-term carbon dynamics of a pristine subtropical headwater stream in Australia, over contrasting hydrologic regimes of drought, flash-flooding and recovery. Observations over 23 days revealed a shift from carbon losses dominated by CO{sub 2} outgassing under conditions of low flow (66.4 ± 0.4% of carbon export) to downstream exports of carbon during the flood (87.8 ± 9.7% of carbon export). DOC was the dominant form of downstream exports throughout the study (DOC:DIC:POC = 0.82:0.05:0.13). The broadest diel variability among variables occurred during the drought phase, with diel variability up to 662 μatm d{sup −1} (or 27 μM [CO{sub 2}*] d{sup −1}), 17 μM d{sup −1} and 268 Bq m{sup −3} d{sup −1} for pCO{sub 2}, dissolved oxygen and {sup 222}Rn, respectively. Diel dynamics indicated multiple interrelated drivers of stream water chemistry including groundwater seepage and in-stream metabolism. The catchment exported terrestrial carbon throughout the field campaign, with a mean net stream flux of 4.7 ± 7.8 mmol C m{sup −2} (catchment area) d{sup −1} which is equivalent to 1.4 ± 2.3% of the estimated local terrestrial net primary production. Our observations highlight the importance of accounting for hydrological extremes when assessing the carbon budgets and ecosystem metabolism of headwater streams, and provide a first estimate of aquatic carbon exports from a pristine Australian subtropical rainforest. - Highlights: • First carbon export estimates of a pristine Australian subtropical headwater catchment. • Metabolism and hydrology were drivers of aquatic carbon flux. �

Carbon cycling and exports over diel and flood-recovery timescales in a subtropical rainforest headwater stream

International Nuclear Information System (INIS)

Looman, Arún; Santos, Isaac R.; Tait, Douglas R.; Webb, Jackie R.; Sullivan, Caroline A.; Maher, Damien T.

2016-01-01

Catchment headwaters comprise the majority of all stream length globally, however, carbon (C) dynamics in these systems remains poorly understood. We combined continuous measurements of pCO_2 and radon ("2"2"2Rn, a natural groundwater tracer) with discrete sampling for particulate organic, dissolved organic and inorganic carbon (POC, DOC, and DIC) to assess the short-term carbon dynamics of a pristine subtropical headwater stream in Australia, over contrasting hydrologic regimes of drought, flash-flooding and recovery. Observations over 23 days revealed a shift from carbon losses dominated by CO_2 outgassing under conditions of low flow (66.4 ± 0.4% of carbon export) to downstream exports of carbon during the flood (87.8 ± 9.7% of carbon export). DOC was the dominant form of downstream exports throughout the study (DOC:DIC:POC = 0.82:0.05:0.13). The broadest diel variability among variables occurred during the drought phase, with diel variability up to 662 μatm d"−"1 (or 27 μM [CO_2*] d"−"1), 17 μM d"−"1 and 268 Bq m"−"3 d"−"1 for pCO_2, dissolved oxygen and "2"2"2Rn, respectively. Diel dynamics indicated multiple interrelated drivers of stream water chemistry including groundwater seepage and in-stream metabolism. The catchment exported terrestrial carbon throughout the field campaign, with a mean net stream flux of 4.7 ± 7.8 mmol C m"−"2 (catchment area) d"−"1 which is equivalent to 1.4 ± 2.3% of the estimated local terrestrial net primary production. Our observations highlight the importance of accounting for hydrological extremes when assessing the carbon budgets and ecosystem metabolism of headwater streams, and provide a first estimate of aquatic carbon exports from a pristine Australian subtropical rainforest. - Highlights: • First carbon export estimates of a pristine Australian subtropical headwater catchment. • Metabolism and hydrology were drivers of aquatic carbon flux. • Catchment exports ranged between 1.1 and 18.6 mmol C m

Grazing alters net ecosystem C fluxes and the global warming potential of a subtropical pasture.

Science.gov (United States)

Gomez-Casanovas, Nuria; DeLucia, Nicholas J; Bernacchi, Carl J; Boughton, Elizabeth H; Sparks, Jed P; Chamberlain, Samuel D; DeLucia, Evan H

2018-03-01

The impact of grazing on C fluxes from pastures in subtropical and tropical regions and on the environment is uncertain, although these systems account for a substantial portion of global C storage. We investigated how cattle grazing influences net ecosystem CO 2 and CH 4 exchange in subtropical pastures using the eddy covariance technique. Measurements were made over several wet-dry seasonal cycles in a grazed pasture, and in an adjacent pasture during the first three years of grazer exclusion. Grazing increased soil wetness but did not affect soil temperature. By removing aboveground biomass, grazing decreased ecosystem respiration (R eco ) and gross primary productivity (GPP). As the decrease in R eco was larger than the reduction in GPP, grazing consistently increased the net CO 2 sink strength of subtropical pastures (55, 219 and 187 more C/m 2 in 2013, 2014, and 2015). Enteric ruminant fermentation and increased soil wetness due to grazers, increased total net ecosystem CH 4 emissions in grazed relative to ungrazed pasture (27-80%). Unlike temperate, arid, and semiarid pastures, where differences in CH 4 emissions between grazed and ungrazed pastures are mainly driven by enteric ruminant fermentation, our results showed that the effect of grazing on soil CH 4 emissions can be greater than CH 4 produced by cattle. Thus, our results suggest that the interactions between grazers and soil hydrology affecting soil CH 4 emissions play an important role in determining the environmental impacts of this management practice in a subtropical pasture. Although grazing increased total net ecosystem CH 4 emissions and removed aboveground biomass, it increased the net storage of C and decreased the global warming potential associated with C fluxes of pasture by increasing its net CO 2 sink strength. © 2017 by the Ecological Society of America.

Carbon and water vapore balance in a primary subtropical evergreen forest in Southewest China under a changing climate

Science.gov (United States)

Song, Q. H.; Zhang, Y. P.

2017-12-01

The Ailaoshan Nature Reserve in Yunnan province, southwestern China hosts about 5000 ha of primary subtropical evergreen mountain cloud forest. A widespread and severe drought occurred in southwestern China in 2009 and 2010, providing a unique opportunity to directly evaluate how water use efficiency (WUE) changes with drought stress in the primary subtropical forest. We calculated WUE using measures of gross primary production (GPP) and evapotranspiration (ET) from five years of continuous eddy covariance measurements (2009-2013) obtained over a primary subtropical evergreen broadleaved forest in southwestern China. Annual mean WUE exhibited a decreasing trend from 2009 to 2013, varying from 2.28 to 2.68 g C kg H2O-1. The multiyear average WUE was 2.48 ± 0.17 (mean ± standard deviation) g C kg H2O-1. WUE increased greatly in the driest year (2009), due to a larger decline in ET than in GPP. Unfortunately, the same study site experienced a particularly extreme climate anomaly during January 2015, with a heavy snow of up to 50 cm in depth, which led to severe forest damage. The forest canopy was severely damaged by the heavy snow, and the leaf area index (LAI) decreased significantly from January to July 2015. GPP, net ecosystem exchange (NEE), and Ecosystem respiration (Reco) all sharply decreased in 2015 after the heavy snow. On average, a strong decrease of 544 g C m-2 year-1 in annual NEE in 2015 was associated with a decrease of 829 g C m-2 year-1 in annual GPP and a decrease of 285 g C m-2 year-1 in annual Reco. Overall, annual net C uptake in 2015 was reduced by 76% compared to the mean C uptake of the previous four years. A sharp increase in carbon uptake was also observed in 2016, indicating that long-term, continuous measurements should be carried out to evaluate the overall response to the disturbance.

Transformation and fate of microphytobenthos carbon in subtropical shallow subtidal sands: A

NARCIS (Netherlands)

Oakes, J.M.; Eyre, B.D.; Middelburg, J.J.

2012-01-01

Microphytobenthos (MPB) in photic sediments are highly productive but the fate of this production remains uncertain. Over 33 d, tracing of C-13 from added bicarbonate in subtropical shallow subtidal sand showed rapid transfer of MPB-derived carbon to deeper sediment; below 2 cm (31% within 60 h) and

Anticyclonic eddies increase accumulation of microplastic in the North Atlantic subtropical gyre

NARCIS (Netherlands)

Brach, Laurent; Deixonne, Patrick; Bernard, Marie France; Durand, Edmée; Desjean, Marie Christine; Perez, Emile; van Sebille, Erik; ter Halle, Alexandra

2018-01-01

There are fundamental gaps in our understanding of the fates of microplastics in the ocean, which must be overcome if the severity of this pollution is to be fully assessed. The predominant pattern is high accumulation of microplastic in subtropical gyres. Using in situ measurements from the 7th

The role of the cold Okhotsk Sea in strengthening of the Pacific subtropical high and Baiu precipitation

Science.gov (United States)

Kawasaki, K.; Tachibana, Y.; Nakamura, T.; Yamazaki, K.; Kodera, K.

2016-12-01

It is commonly known that the formation of a stationery precipitation zone in association with the Baiu front is influenced by the existence of the warm Tibetan Plateau. Some GCM studies in which the Tibetan Plateau is removed pointed out that without the Tibetan Plateau, the Baiu front wound not appear. The cold Okhotsk Sea, which is located to the north of Japan, is also important in forming cold air for the Bai front. This study focused on the role of the Okhotsk Sea in the formation of the Baiu front by using an atmospheric GCM. One GCM is executed without the Okhotsk Sea, in which was changed to an eastern part of the Eurasian continent as if the Okhotsk Sea was totally landfilled (land run). The other (sea run) is a control run under the boundary condition of climatic seasonal changes of the SST over the globe. The comparison of the land run with the sea run showed that precipitation over Japan would weaken in the Baiu season without the Okhotsk Sea, indicating that the existence of the Okhotsk Sea has an impact on the increase in precipitation. The precipitation increase in the sea run is directly accounted by the strengthening of southeast wind in association with the strengthening of the subtropical high located over the Pacific Ocean (Fig. 1). The westerly jet, which is located at the northern part of the subtropical high, was also accelerated in the sea run. The subtropical high in association with the accelerated jet was strengthened by meridional atmospheric thermal gradient caused by underlying cold Okhotsk Sea and the warm Pacific Ocean. The strengthened thermal gradient also activated the storm track that extends zonally over the Okhotsk Sea, and the activated storm track further strengthened the jet and subtropical high by wave-mean flow feedback. This feedback loop could further strengthen the Baiu precipitation. In consequence, the Okhotsk plays a significant role in the strengthening the subtropical high and its associated Baiu precipitation.

Acid deposition and assessment of its critical load for the environmental health of waterbodies in a subtropical watershed, China

Science.gov (United States)

Jia, Junjie; Gao, Yang

2017-12-01

Atmospheric acidic deposition in subtropical watersheds poses an environmental risk of causing acidification of aquatic ecosystems. In this study, we evaluated the frequency of acid deposition in a subtropical forest ecosystem and the associated critical loads of acidity for a sensitive aquatic ecosystem. We found that out of 132 rainfall events, 33(25%) were acidic rainfall occurrences. Estimated wet acid deposition (2282.78 eq·ha-1·yr-1), consistent with SO42- and NH4+ deposition, was high in spring and summer and low in autumn and winter. Waterbodies surrounded by mixed wood and citrus orchard experience severe acidification, mostly from S deposition because acidic deposition exceeds the corresponding critical loads of acidity. Modifications that take acid rain deposition into consideration are needed for land-use and agricultural management strategies to improve the environmental health of waterbodies in subtropical watersheds.

Subtropical Climate Variability since the Last Glacial Maximum from Speleothem Precipitation Reconstructions in Florida

Science.gov (United States)

Polk, J.; van Beynen, P.; DeLong, K. L.; Asmerom, Y.; Polyak, V. J.

2017-12-01

Teleconnections between the tropical-subtropical regions of the Americas since the Last Glacial Maximum (LGM), particularly the Mid- to Late-Holocene, and high-resolution proxy records refining climate variability over this period continue to receive increasing attention. Here, we present a high-resolution, precisely dated speleothem record spanning multiple periods of time since the LGM ( 30 ka) for the Florida peninsula. The data indicate that the amount effect plays a significant role in determining the isotopic signal of the speleothem calcite. Collectively, the records indicate distinct differences in climate in the region between the LGM, Mid-Holocene, and Late Holocene, including a progressive shift in ocean composition and precipitation isotopic values through the period, suggesting Florida's sensitivity to regional and global climatic shifts. Comparisons between speleothem δ18O values and Gulf of Mexico marine records reveal a strong connection between the Gulf region and the terrestrial subtropical climate in the Late Holocene, while the North Atlantic's influence is clear in the earlier portions of the record. Warmer sea surface temperatures correspond to enhanced evaporation, leading to more intense atmospheric convection in Florida, and thereby modulating the isotopic composition of rainfall above the cave. These regional signals in climate extend from the subtropics to the tropics, with a clear covariance between the speleothem signal and other proxy records from around the region, as well as global agreement during the LGM period with other records. These latter connections appear to be driven by changes in the mean position of the Intertropical Convergence Zone and time series analysis of the δ18O values reveals significant multidecadal periodicities in the record, which are evidenced by agreement with the AMV and other multidecadal influences (NAO and PDO) likely having varying influence throughout the period of record. The climate variability

Retention of available P in acid soils of tropical and subtropical evergreen broad-leaved forests

Institute of Scientific and Technical Information of China (English)

CHEN Jianhui; ZOU Xiaoming; YANG Xiaodong

2007-01-01

Precipitation of mineral phosphate is often recognized as a factor of limiting the availability of P in acidic soils of tropical and subtropical forests.For this paper,we studied the extractable P pools and their transformation rates in soils of a tropical evergreen forest at Xishuangbanna and a subtropical montane wet forest at the Ailao Mountains in order to understand the biogeochemical processes regulating P availability in acidic soils.The two forests differ in forest humus layer;it is deep in the Ailao forest while little is present in the Xishuangbanna forest.The extractable P pools by resin and sodium-bicarbonate decreased when soil organic carbon content was reduced.The lowest levels of extractable P pools occurred in the surface (0-10 era) mineral soils of the Xishuangbanna forest.However,microbial P in the mineral soil of the Xishuangbauna forest was twice that in the Ailao forest.Potential rates of microbial P immobilization were greater than those of organic P mineralization in mineral soils for both forests.We suggest that microbial P immobilization plays an essential role in avoiding mineral P precipitation and retaining available P of plant in tropical acidic soils,whereas both floor mass accumulation and microbial P immobilization function benefit retaining plant available P in subtropical montane wet forests.

Propagation of Native Tree Species to Restore Subtropical Evergreen Broad-Leaved Forests in SW China

Directory of Open Access Journals (Sweden)

Yang Lu

2016-01-01

Full Text Available Subtropical evergreen broad-leaved forest (EBLF is a widespread vegetation type throughout East Asia that has suffered extensive deforestation and fragmentation. Selection and successful propagation of native tree species are important for improving ecological restoration of these forests. We carried out a series of experiments to study the propagation requirements of indigenous subtropical tree species in Southwest China. Seeds of 21 tree species collected from the natural forest were materials for the experiment. This paper examines the seed germination and seedling growth performance of these species in a nursery environment. Germination percentages ranged from 41% to 96% and were ≥50% for 19 species. The median length of germination time (MLG ranged from 24 days for Padus wilsonii to 144 days for Ilex polyneura. Fifteen species can reach the transplant size (≥15 cm in height within 12 months of seed collection. Nursery-grown seedlings for each species were planted in degraded site. Two years after planting, the seedling survival rate was >50% in 18 species and >80% in 12 species. Based on these results, 17 species were recommended as appropriate species for nursery production in forest restoration projects. Our study contributes additional knowledge regarding the propagation techniques for various native subtropical tree species in nurseries for forest restoration.

Pre-travel preparation practices among business travellers to tropical and subtropical destinations: results from the Athens International Airport Survey.

Science.gov (United States)

Pavli, Androula; Silvestros, Chrysovalantis; Patrinos, Stavros; Lymperi, Ioanna; Maltezou, Helena C

2014-01-01

The number of business travellers from Greece to tropical and subtropical areas has recently increased. The study aimed to assess travel health preparation practices of business travellers departing to Africa, the Middle East and Asia. A questionnaire-based survey was conducted at Athens International Airport, from 1st of November 2011 to 30th of April 2013. A total of 684 business travellers participated in the study; the majority were men (86.1%), of Greek nationality (95.3%), with tertiary education (90.8%) and employed (98%). Their mean age was 40 years; 62% and 26% of them were 35-49 and 19-34 years of age respectively. 84.8% were travelling alone. Most frequent destinations were the Middle East (46.8%) and sub-Saharan Africa (16%). For 23.5% of the travellers it was their first trip to a tropical or subtropical country. Only 58.8% pursued pre-travel health consultation; vaccination and malaria chemoprophylaxis were administered to 24.7% and 25.7% of the travellers, respectively. Hepatitis A and typhoid vaccination rates were lower than expected (70% and 35%, respectively). Nearly half of the travellers who visited malaria endemic areas did not receive any chemoprophylaxis. Having elementary education level, travelling to the Middle East or North Africa, travelling for less than 1 month duration, and staying in a house or a hotel were associated with a higher probability of not pursuing health consultation. Significant gaps were found in pre-travel health practices of business travellers departing to Africa, the Middle East and Asia. Strategies should be developed in order to improve awareness of business travellers. Copyright © 2013 Elsevier Ltd. All rights reserved.

The South-American distribution and southernmost record of Biomphalaria peregrina—a potential intermediate host of schistosomiasis

Directory of Open Access Journals (Sweden)

Alejandra Rumi

2017-05-01

Full Text Available Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South-American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas

Distribution of the species of Lucifer Thompson, 1829 in the subtropical South Atlantic between parallels 20º and 30ºs

Directory of Open Access Journals (Sweden)

André Marafon-Almeida

Full Text Available Abstract The distribution of the species of Lucifer Thompson, 1829 (Decapoda: Luciferidae in the South Atlantic Subtropical Gyre was assessed by the Brazil Transatlantic Commission in November and December 2009. The samples were collected at 83 stations on two profiles between Brazil and Africa (20 º and 30 ºS. Oblique hauls were performed with a WP-2 net up to 150 meters deep. A distinct sexual relationship was noted between the two species found and L. faxoni presented a significantly higher number of females relative to males 1:0.5 (X2 = 21.77, p = 0.0001. The L. typus sex ratio had significantly more males than females 1.86:1 (X2=50.84, p = 0.0001. The distribution of L. typus occurred in both the western and the eastern portions of the Mid-Oceanic Ridge. This distribution was significantly related to salinity (R2 = 0:13; F = 3.79, p = 0.009, which was higher in the western portion of the study area. In addition, the recordings of the two species were extended to the Atlantic Subtropical Gyre. Overall, Luciferidae shrimp were more common and abundant at the stations west of the Mid-Oceanic Ridge and L. typus was the most frequent and abundant species.

Organic carbon budget for the eastern boundary of the North Atlantic subtropical gyre: major role of DOC in mesopelagic respiration.

Science.gov (United States)

Santana-Falcón, Yeray; Álvarez-Salgado, Xosé Antón; Pérez-Hernández, María Dolores; Hernández-Guerra, Alonso; Mason, Evan; Arístegui, Javier

2017-08-31

Transports of suspended particulate (POC susp ) and dissolved (DOC) organic carbon are inferred from a box-model covering the eastern boundary of the North Atlantic subtropical gyre. Corresponding net respiration rates (R) are obtained from a net organic carbon budget that is based on the transport estimates, and includes both vertical and lateral fluxes. The overall R in the mesopelagic layer (100-1500 m) is 1.6 ± 0.4 mmol C m -2 d -1 . DOC accounts for up to 53% of R as a result of drawdown of organic carbon within Eastern North Atlantic Central Water (ENACW) that is entrained into sinking Mediterranean Overflow Water (MOW) that leads to formation of Mediterranean water (MW) at intermediate depths (~900 m). DOC represents 90% of the respired non-sinking organic carbon. When converted into oxygen units, the computed net respiration rate represents less than half the oxygen utilization rates (OUR) reported for the mesopelagic waters of the subtropical North Atlantic. Mesoscale processes in the area, not quantified with our approach, could account in part for the OUR differences observed between our carbon budget and other published studies from the North Atlantic, although seasonal or interannual variability could also be responsible for the difference in the estimates.

Descriptions of the immature stages and new host plant records of Notozulia entreriana (Berg) (Hemiptera: Cercopidae) pests of grasses in subtropical areas of the Americas.

Science.gov (United States)

Foieri, Alvaro; Lenicov, Ana M Marino De Remes; Virla, Eduardo G

2016-04-11

Notozulia entreriana (Berg) (Hemiptera: Cercopidae) is one of the most common spittlebugs inhabiting the subtropical region of the America, inflicting important economic damage to grass crops. The immature stages are described and illustrated; the main characteristics that distinguish instars are the body size, color, number of flagellomeres, and number of tibial and metatarsomere spines. A key for identification of nymphs is provided as a tool to develop field studies.  Nine host plants, all belonging to Poaceae, are recorded as breeding and feeding host plants from different localities in northern Argentina.

Direct Evidence for PCB Destruction in the Subtropical Troposphere by OH Radicals

Science.gov (United States)

Mandalakis, M.; Berresheim, H.; Stephanou, E.

2003-04-01

Although polychlorinated biphenyls (PCBs) production and use were banned by the mid-1970s, PCBs are ubiquitous pollutants in nearly all environmental compartments. Because of their high persistence and toxicity PCBs can pose toxic effects on animals and humans, decades after their release into the environment. It has been supported that warm temperatures at the tropical and subtropical regions of the earth favor the volatilization of PCBs, which are subsequently transported to colder areas of high latitude. This process, known as "global distillation effect", could cause an enhancement of PCB concentrations in the plant biomass and the marine mammals of Earth's polar regions. It has been experimentally established, that chemical reactions of PCBs with OH radicals might be the dominant loss processes in the atmosphere1. Nevertheless, PCBs atmospheric removal by OH radicals has never been positively demonstrated under real atmospheric conditions, mainly due to the difficulties to measure simultaneously the concentration of OH radicals and PCBs in the atmosphere. By applying elaborated sampling and analytical techniques2,3, under real atmospheric conditions, we achieved the simultaneous determination of OH radicals and PCBs congeners and demonstrated for the first time that PCB removal from the troposphere of subtropical regions is due to a large extent to reactions with OH radicals. References 1. Anderson, P. N. &Hites, R. A. OH radical reactions: The major removal pathway for polychlorinated biphenyls from the atmosphere. Environ. Sci. Technol. 30, 1756-1763 (1996). 2. Berresheim, H., Elste, T., Plass-Dülmer, C., Eisele, F. L. &Tanner, D. J. Chemical ionization mass spectrometer for long-term measurements of atmospheric OH and H2SO4. Int. J. Mass Spectrom. 202, 91-109 (2000). 3. Mandalakis, M., M. Tsapakis, and E.G. Stephanou, Optimization and application of high-resolution gas chromatography with ion trap tandem mass spectrometry to the determination of

Reproductive biology of the swamp racer Mastigodryas bifossatus (Serpentes: Colubridae in subtropical Brazil

Directory of Open Access Journals (Sweden)

Pedro T. Leite

2009-03-01

Full Text Available The swamp racer Mastigodryas bifossatus (Raddi, 1820 is a large snake of Colubrinae. It is widely distributed in open areas throughout South America. Dissection of 224 specimens of this species housed in herpetological collections of the southern Brazilian states of Rio Grande do Sul, Santa Catarina and Paraná provided information on its sexual dimorphism, reproductive cycle and fecundity in subtropical Brazil. Adult specimens of M. bifossatus average approximately 1190 mm in snout-vent length and females are larger than males. The reproductive cycle of females is seasonal, with secondary vitellogenesis occurring from July to December. However, examination of male gonads did not reveal signs of reproductive seasonality in this sex. Egg laying was recorded from November to January. The estimated recruitment period extends from February to April. The mean number of individuals per clutch is 15, and there is a positive correlation between female length and clutch size.

INFLUENCE OF LIGHT ON BACTERIOPLANKTON PRODUCTION AND RESPIRATION IN A SUBTROPICAL CORAL REEF

Science.gov (United States)

The influence of sunlight on bacterioplankton production (14C-leucine (Leu) and 3H-thymidine (TdR) incorporation; changes in cell abundances) and O2 consumption was investigated in a shallow subtropical coral reef located near Key Largo, Florida. Quartz (light) and opaque (dark) ...

Brief history of the development of the Subtropical Botanical Garden of the Kuban

Directory of Open Access Journals (Sweden)

Karpun Yuriy Nikolaevich

2017-12-01

Full Text Available A retrospective report of the Director of the Subtropical Botanical Garden of Kuban, Karpun YN, at the opening of the First National Dendrological Conference, dedicated to the 40th anniversary of the Garden, held on March 14-16, 2017 in Sochi

Regimes of Diurnal Variation of Summer Rainfall over Subtropical East Asia

Energy Technology Data Exchange (ETDEWEB)

Yuan W.; Lin W.; Yu, R.; Zhang, M.; Chen, H.; Li, J.

2012-05-01

Using hourly rain gauge records and Tropical Rainfall Measuring Mission 3B42 from 1998 to 2006, the authors present an analysis of the diurnal characteristics of summer rainfall over subtropical East Asia. The study shows that there are four different regimes of distinct diurnal variation of rainfall in both the rain gauge and the satellite data. They are located over the Tibetan Plateau with late-afternoon and midnight peaks, in the western China plain with midnight to early-morning peaks, in the eastern China plain with double peaks in late afternoon and early morning, and over the East China Sea with an early-morning peak. No propagation of diurnal phases is found from the land to the ocean across the coastlines. The different diurnal regimes are highly correlated with the inhomogeneous underlying surface, such as the plateau, plain, and ocean, with physical mechanisms consistent with the large-scale 'mountain-valley' and 'land-sea' breezes and convective instability. These diurnal characteristics over subtropical East Asia can be used as diagnostic metrics to evaluate the physical parameterization and hydrological cycle of climate models over East Asia.

Surface energy exchanges over contrasting vegetation types on a subtropical sand island

Science.gov (United States)

Gray, Michael; McGowan, Hamish; Lowry, Andrew; Guyot, Adrien

2017-04-01

The surface energy balance of subtropical coastal vegetation communities has thus far received little attention. Here we present a multi-year observational data set using the eddy covariance method to quantify for the first time the surface energy balance over three contrasting vegetation types on a subtropical sand island in eastern Australia: a periodically inundated sedge swamp, an exotic pine plantation and a coastal heath. Maximum daily sensible heat flux varied between sites but was typically > 280 Wm-2 in the coastal heath and pine plantation but no more than 250 Wm-2 in the swamp when dry and 1. The partitioning of energy, as represented by β, is similar to a variety of Australian ecosystems, and a range of coastal vegetation types in other latitudes, but differs from other tropical or subtropical locations which have strongly seasonal rainfall patterns and therefore a switch from β > 1 before rainfall to β changes in background meteorology with the most important influences being net radiation, absolute humidity, and rainfall. The main factor differentiating the sites was soil water content, with the remnant coastal heath and swamp having ready access to water but the exotic pine plantation having much drier soils. Should the current balance between remnant vegetation and the pine plantation undergo changes there would be a corresponding shift in the surface energy balance of the island as a whole, and altered plant water use may lead to reduced water table depth, important because the groundwater of the local islands is used as part of a regional water grid. A better understanding of the response of coastal vegetation to atmospheric forcing will enable more informed decision making on land use changes, as coastal regions the world over face development pressure.

The Outlier Sectors: Areas of Non-Free Trade in the North American Free Trade Agreement

OpenAIRE

Eric T. Miller

2002-01-01

Since its entry into force, the North American Free Trade Agreement (NAFTA) has been enormously influential as a model for trade liberalization. While trade in goods among Canada, the United States and Mexico has been liberalized to a significant degree, this most famous of agreements nonetheless contains areas of recalcitrant protectionism. The first part of this paper identifies these "outlier sectors" and classifies them by primary source advocating protectionism, i.e., producer interests ...

Organomineral Interactions and Herbicide Sorption in Brazilian Tropical and Subtropical Oxisols under No-Tillage.

Science.gov (United States)

Bonfleur, Eloana J; Kookana, Rai S; Tornisielo, Valdemar L; Regitano, Jussara B

2016-05-25

We evaluated the effects of the soil organic matter (SOM) composition, distribution between soil aggregates size, and their interactions with the mineral phase on herbicide sorption (alachlor, bentazon, and imazethapyr) in tropical and subtropical Oxisols under no-till systems (NT). Using soil physical fractionation approach, sorption experiments were performed on whole soils and their aggregates. SOM chemistry was assessed by CP/MAS (13)C NMR. The lower sorption observed in tropical soils was attributed to the greater blockage of SOM sorption sites than in subtropical soils. When these sites were exposed upon physical fractionation, sorption of the three herbicides in tropical soils increased, especially for imazethapyr. High amounts of poorly crystallized sesquioxides in these soils may have contributed to masking of sorption sites, indicating that organomineral interactions may lead to blockage of sorption sites on SOM in tropical soils.

Subtropical westerly jet waveguide and winter persistent heavy rainfall in south China

Science.gov (United States)

Ding, Feng; Li, Chun

2017-07-01

Using observed daily precipitation and National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis data, what induced winter large spatial persistent heavy rainfall (PHR) events in south China was examined, based on composite analyses of 30 large spatial PHR events during 1951-2015. The results showed that wave trains within North Africa-Asia (NAA) westerly jet existed in upper troposphere during these PHR processes. The wave trains shared the characteristic of a Rossby wave. The Rossby wave originated from northwest Europe, entered into the NAA jet through strong cold air advection to form convergence over the Mediterranean, and then propagated eastward along subtropical NAA jet. The Rossby wave propagated toward Southeast Asia and caused strong divergence in the upper troposphere. The strong divergence in the upper troposphere induced vertical convection and favored large spatial PHR events in south China. In addition, the enhanced India-Burma trough and subtropical high in the northwestern Pacific supplied enough water vapor transportation. This mechanism would be useful to the medium-range forecast of such winter rainfall processes over south China.

Estimations of evapotranspiration in an age sequence of Eucalyptus plantations in subtropical China.

Directory of Open Access Journals (Sweden)

Wenfei Liu

Full Text Available Eucalyptus species are widely planted for reforestation in subtropical China. However, the effects of Eucalyptus plantations on the regional water use remain poorly understood. In an age sequence of 2-, 4- and 6-year-old Eucalyptus plantations, the tree water use and soil evaporation were examined by linking model estimations and field observations. Results showed that annual evapotranspiration of each age sequence Eucalyptus plantations was 876.7, 944.1 and 1000.7 mm, respectively, accounting for 49.81%, 53.64% and 56.86% of the annual rainfall. In addition, annual soil evaporations of 2-, 4- and 6-year-old were 318.6, 336.1, and 248.7 mm of the respective Eucalyptus plantations. Our results demonstrated that Eucalyptus plantations would potentially reduce water availability due to high evapotranspiration in subtropical regions. Sustainable management strategies should be implemented to reduce water consumption in Eucalyptus plantations in the context of future climate change scenarios such as drought and warming.

The study of azaarene behavior over atmosphere of subtropical city(Keelung)

Science.gov (United States)

Liu, Chih Yun

2017-04-01

In this study, we collected the Total Suspended Particulates (TSP) from July 2014 to February 2016 in the subtropical city (Keelung), and researched azaarene behavior over atmosphere. Polycyclic Aromatic Compounds (PAHs) are ubiquitous pollutants in the environment; they have known carcinogens and/or mutagens, mainly produce from incomplete combustion. Azaarenes are polycyclic aromatic hydrocarbon derivative compounds in which a carbon atom in one of the aromatic rings is substituted by a nitrogen atom. Organism exposure to azaarenes occurs through inhalation of polluted air and by ingestion of food and/or water containing combustion products and accumulate in the body. Total azaarene concentration (16 individual compound concentration of the aggregate) is between 0.92 to 3.76 μg/m3, results showed that the concentration of azaarenes have significant seasonal variation, they have higher concentration in the cold month. In molecular weight, the highest proportion is the molecular weight equal to 143(ΣMQ) and then the molecular weight equal to 179(BAP), ΣMQ would rise from 30% 40% to 40% 50% during the cold month and warm months. Compared to ring number, 2-rings are biggest part, the smallest is 4-rings, its ratio has slight variation, but primary species is 2-rings. Emissions from transportation, local housing heating, factories burning fossil fuels and dust from Mainland south air mass are pollutant, their sources and climate conditions can affect concentration and composition of compound. There are highly significant correlation between 3-rings and 4-rings, which suggests that there are similar source strengths and transport mechanisms for these compounds. Correlation between concentration of azaarenes and ambient temperature is negative moderation, with concentration of atmospheric suspended particles is positive moderate correlation. Finally, we establish the relationship between the three parameters to predict concentration of azaarenes over atmosphere of

Response of Termite (Blattodea: Termitoidae) Assemblages to Lower Subtropical Forest Succession: A Case Study in Dinghushan Biosphere Reserve, China.

Science.gov (United States)

Li, Zhi-Qiang; Ke, Yun-Ling; Zeng, Wen-Hui; Zhang, Shi-Jun; Wu, Wen-Jing

2016-02-01

Termite (Blattodea: Termitoidae) assemblages have important ecological functions and vary in structure between habitats, but have not been studied in lower subtropical forests. To examine whether differences in the richness and relative abundance of termite species and functional groups occur in lower subtropical regions, termite assemblages were sampled in Dinghushan Biosphere Reserve, China, among pine forest, pine and broad-leaved mixed forest (mixed forest), and monsoon evergreen broad-leaved forest (monsoon forest). The dominant functional group was wood-feeding termites (family Termitidae), and the mixed forest hosted the greatest richness and relative abundance. Soil-feeding termites were absent from the lower subtropical system, while humus-feeding termites were sporadically distributed in mixed forest and monsoon forest. The species richness and functional group abundance of termites in our site may be linked to the forest succession. Altitude, soil temperature, air temperature, surface air relative humidity, and litter depth were significant influences on species and functional group diversity.

The application of lichens as ecological surrogates of air pollution in the subtropics: a case study in South Brazil.

Science.gov (United States)

Koch, Natália M; Branquinho, Cristina; Matos, Paula; Pinho, Pedro; Lucheta, Fabiane; Martins, Suzana M A; Vargas, Vera M F

2016-10-01

The use of lichens as ecological surrogates has been an important tool to evaluate the impact of air pollution in both ecosystem and human health but remains underused in the subtropics due to lack of knowledge. Aiming to support the application of lichen as ecological surrogates of the effects of air pollution in the subtropics, we hypothesized that urbanization was an important driver of changes on lichen diversity, composition, and vitality. For that, we quantified several lichen diversity metrics (richness, cover, and community composition) and photobiont vitality in relation to atmospheric pollution or its surrogates (modeled pollutant gases, pollutants in lichen thallus, and land cover). We confirmed that air pollution was a key driver for lichen diversity. Changes in lichen community composition and vitality were very significantly related to air pollution and integrated the effect of multiple stressors (particulate matter, NOx, and Cu), thus being powerful ecological indicators of air pollution in the subtropics.

Spatio-temporal patterns and predictions of phytoplankton assemblages in a subtropical river delta system

DEFF Research Database (Denmark)

Wang, Chao; Li, Xinhui; Wang, Xiangxiu

2016-01-01

Spatial and seasonal sampling within a subtropical river delta system, the Pearl River Delta (China), provided data to determine seasonal phytoplankton patterns and develop prediction models. The high nutrient levels and frequent water exchanges resulted in a phytoplankton community with greatest...

The western boundary current of the seasonal subtropical gyre in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Shetye, S.R.; Gouveia, A.D.; Shenoi, S.S.C.; Sundar, D.; Michael, G.S.; Nampoothiri, G.

, and monthly mean wind stress, we propose that the poleward current is the western boundary current of a seasonal anticyclonic subtropical gyre which forms in the Bay during January, is best developed during March-April, and decays by June. The gyre...

Examining South Atlantic Subtropical Cyclone Anita using the Satellite-Enhanced Regional Downscaling for Applied Studies Hourly Outputs

Science.gov (United States)

Vaicberg, H.; Palmeira, A. C. P. A.; Nunes, A.

2017-12-01

Studies on South Atlantic cyclones are mainly compromised by scarcity of observations. Therefore, remote sensing and global (re) analysis products are usually employed in investigations of their evolution. However, the frequent use of global reanalysis might difficult the assessment of the characteristics of the cyclones found in South Atlantic. In that regard, studies on "subtropical" cyclones have been performed using the 25-km resolution, Satellite-enhanced Regional Downscaling for Applied Studies (SRDAS), a product developed at the Federal University of Rio de Janeiro in Brazil. In SRDAS, the Regional Spectral Model assimilates precipitation estimates from environmental satellites, while dynamically downscaling a global reanalysis using the spectral nudging technique to maintain the large-scale features in agreement with the regional model solution. The use of regional models in the downscaling of general circulation models provides more detailed information on weather and climate. As a way of illustrating the usefulness of SRDAS in the study of the subtropical South Atlantic cyclones, the subtropical cyclone Anita was selected because of its intensity. Anita developed near Brazilian south/southeast coast, with damages to local communities. Comparisons with available observations demonstrated the skill of SRDAS in simulating such an extreme event.

Performance evaluation of photovoltaic-thermosyphon system for subtropical climate application

Energy Technology Data Exchange (ETDEWEB)

Chow, T.T.; He, W.; Chan, A.L.S. [Division of Building Science and Technology, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR (China); Ji, J. [Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Anhui (China)

2007-01-15

The rapid development and sales volume of photovoltaic (PV) modules has created a promising business environment in the foreseeable future. However, the current electricity cost from PV is still several times higher than from the conventional power generation. One way to shorten the payback period is to bring in the hybrid photovoltaic-thermal (PVT) technology, which multiplies the energy outputs from the same collector surface area. In this paper, the performance evaluation of a new water-type PVT collector system is presented. The thermal collection making use of the thermosyphon principle eliminates the expense of pumping power. Experimental rigs were successfully built. A dynamic simulation model of the PVT collector system was developed and validated by the experimental measurements, together with two other similar models developed for PV module and solar hot-water collector. These were then used to predict the energy outputs and the payback periods for their applications in the subtropical climate, with Hong Kong as an example. The numerical results show that a payback period of 12 year for the PVT collector system is comparable to the side-by-side system, and is much shorter than the plain PV application. This is a great encouragement in marketing the PVT technology. (author)

Performance evaluation of photovoltaic-thermosyphon system for subtropical climate application

International Nuclear Information System (INIS)

Chow, T.T.; He, W.; Chan, A.L.S.; Ji, J.

2007-01-01

The rapid development and sales volume of photovoltaic (PV) modules has created a promising business environment in the foreseeable future. However, the current electricity cost from PV is still several times higher than from the conventional power generation. One way to shorten the payback period is to bring in the hybrid photovoltaic-thermal (PVT) technology, which multiplies the energy outputs from the same collector surface area. In this paper, the performance evaluation of a new water-type PVT collector system is presented. The thermal collection making use of the thermosyphon principle eliminates the expense of pumping power. Experimental rigs were successfully built. A dynamic simulation model of the PVT collector system was developed and validated by the experimental measurements, together with two other similar models developed for PV module and solar hot-water collector. These were then used to predict the energy outputs and the payback periods for their applications in the subtropical climate, with Hong Kong as an example. The numerical results show that a payback period of 12 year for the PVT collector system is comparable to the side-by-side system, and is much shorter than the plain PV application. This is a great encouragement in marketing the PVT technology. (author)

Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

OpenAIRE

Lundgren, Karin; Kjellström, Tord

2013-01-01

Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly elect...

Development of equations for predicting Puerto Rican subtropical dry forest biomass and volume

Science.gov (United States)

Thomas J. Brandeis; Matthew Delaney; Bernard R. Parresol; Larry Royer

2006-01-01

Carbon accounting, forest health monitoring and sustainable management of the subtropical dry forests of Puerto Rico and other Caribbean Islands require an accurate assessment of forest aboveground biomass (AGB) and stem volume. One means of improving assessment accuracy is the development of predictive equations derived from locally collected data. Forest inventory...

American Indian Areas Located in Region 2 (CENSUS.AM_INDIAN_AREAS_R2)

Data.gov (United States)

U.S. Environmental Protection Agency — There are both legal and statistical American Indian, Alaska Native, and native Hawaiian entities for which the U.S. Census Bureau provides data for Census 2000. The...

Nematode parasite control of livestock in the tropics/subtropics: the need for novel approaches.

Science.gov (United States)

Waller, P J

1997-10-01

Because parasites are more abundant, small ruminants in the tropical/subtropical regions of the world experience much greater ravages from internal parasitic disease than those in the temperate regions. In the tropics/subtropics, the limiting ecological factor influencing the severity of parasitism is rainfall, as temperatures almost always favour hatching and development of the free-living stages. Attempts to expand sheep and goat production by replacing traditional village production systems, which rarely involve anthelmintic treatment, with large-scale intensive commercial enterprises invariably induce complete reliance on anthelmintics to control nematode parasites. This has led to the widespread development of high level, multiple anthelmintic resistance throughout the tropics/subtropics, and in certain regions this has reached the ultimate disastrous scenario of total chemotherapeutic failure. Immediate concerted efforts are needed to resolve this crisis. Significant benefits are likely to emerge from research into non-chemotherapeutic approaches to nematode parasite control, such as grazing management, worm vaccines, breed selection and biological control. However, it is likely that none, in isolation or collectively, will completely replace the need for effective anthelmintics. What is needed is the integration of all methods of parasite control as they come to hand, with the underlying aim of reducing the use and thus preserving the effectiveness of anthelmintics. Although cheap and simple procedures, based on sound epidemiological principles, can achieve dramatic benefits in worm control, they have been poorly adopted by livestock owners. Clearly then, the greatest need is for technology transfer and education programmes, but these activities are generally found to be chronically under-resourced.

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang, E-mail: ywang@magnet.fsu.edu [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States); Gu, Binhe [South Florida Water Management District, West Palm Beach, FL 33406 (United States); Lee, Ming-Kuo [Department of Geology and Geography, Auburn University, Auburn, AL 36839 (United States); Jiang, Shijun, E-mail: sjiang@jnu.edu.cn [Institute of Hydrobiology/Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou, Guangdong 510632 (China); Xu, Yingfeng [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States)

2014-07-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

International Nuclear Information System (INIS)

Wang, Yang; Gu, Binhe; Lee, Ming-Kuo; Jiang, Shijun; Xu, Yingfeng

2014-01-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Atmospheric Mercury Deposition to a Remote Islet in the Subtropical Northwest Pacific Ocean

Science.gov (United States)

Sheu, G.; Lin, N.

2013-12-01

Thirty-four weekly rainwater samples were collected in 2009 at Pengjiayu, a remote islet in the subtropical Northwest (NW) Pacific Ocean with an area of 1.14 km^2, to study the distribution of rainwater mercury (Hg) concentrations and associated wet deposition fluxes. This is the first study concerning wet Hg deposition to the subtropical NW Pacific Ocean downwind of the East Asian continent, which is the major source region for Hg emissions worldwide. Sample Hg concentrations ranged from 2.25 to 22.33 ng L^-1, with a volume-weighted mean (VWM) concentration of 8.85 ng L^-1. The annual wet Hg deposition flux was 10.18 μg m^-2, about 2.5 times the fluxes measured at sites on the Pacific coast of the USA, supporting the hypothesis that deposition is higher in the western than in the eastern Pacific. Seasonal VWM concentrations were 7.23, 11.58, 7.82, and 9.84 ng L^-1, whereas seasonal wet deposition fluxes were 2.14, 3.45, 2.38, and 2.21 μg m^-2, for spring, summer, fall and winter, respectively. Higher summer wet Hg deposition was a function of both higher rainwater Hg concentration and greater rainfall. The seasonal pattern of rainwater Hg concentrations was the opposite of the general seasonal pattern of the East Asian air pollutant export. Since there is no significant anthropogenic Hg emission source on the islet of Pengjiayu, the observed high summertime rainwater Hg concentration hints at the importance of Hg(0) oxidation and/or scavenging of upper-altitude reactive gaseous Hg (RGM) by deep convection. Direct anthropogenic RGM emissions from the East Asian continent may not contribute significantly to the rainwater Hg concentrations, but anthropogenic Hg(0) emissions could be transported to the upper troposphere or marine boundary layer where they can be oxidized to produce RGM, which will then be effectively scavenged by cloud water and rainwater.

Stability and activity of anaerobic sludge from UASB reactors treating sewage in subtropical regions

NARCIS (Netherlands)

Seghezzo, L.; Cuevas, C.M.; Trupiano, A.P.; Guerra, R.G.; Gonzalez, S.M.; Zeeman, G.; Lettinga, G.

2006-01-01

The production of small amounts of well-stabilized biological sludge is one of the main advantages of upflow anaerobic sludge bed (UASB) reactors over aerobic wastewater treatment systems. In this work, sludge produced in three pilot-scale UASB reactors used to treat sewage under subtropical

Decadal phytoplankton dynamics in response to episodic climatic disturbances in a subtropical deep freshwater ecosystem.

Science.gov (United States)

Ko, Chia-Ying; Lai, Chao-Chen; Hsu, Huang-Hsiung; Shiah, Fuh-Kwo

2017-02-01

Information of the decadal timescale effects of episodic climatic disturbances (i.e., typhoons) on phytoplankton in freshwater ecosystems have received less attention and fewer seasonal evaluations partly due to the lack of long-term time-series monitoring data in typhoon prevailing areas. Through field observations of a total 36 typhoon cases in a subtropical deep freshwater ecosystem in the period of 2005-2014, we quantified phytoplankton biomass, production and growth rate in response to meteorological and hydrological changes in the weeks before, during and after typhoons between summer and autumn, and also investigated the effects of typhoon characteristics on the aforementioned phytoplankton responses. The results showed that phytoplankton exposed to typhoon disturbances generally exhibited an increasing trend over the weeks before, during and after typhoons in summer but varied in autumn. The correlations and multivariate regressions showed different contributions of meteorological and hydrological variables to individual phytoplankton responses before, during and after typhoons between seasons. The post-typhoon weeks (i.e., within two weeks after a typhoon had passed) were especially important for the timeline of phytoplankton increases and with a detectable seasonal variation that the chlorophyll a concentration significantly increased in autumn whereas both primary production and growth rate were associated with significant changes in summer. Additionally, phytoplankton responses during the post-typhoon weeks were significantly different between discrete or continuous types of typhoon events. Our work illustrated the fact that typhoons did influence phytoplankton responses in the subtropical deep freshwater ecosystem and typhoon passages in summer and autumn affected the phytoplankton dynamics differently. Nevertheless, sustained and systematic monitoring in order to advance our understanding of the role of typhoons between seasons in the modulation of

The role of coral-associated bacterial communities in Australian Subtropical White Syndrome of Turbinaria mesenterina.

Science.gov (United States)

Godwin, Scott; Bent, Elizabeth; Borneman, James; Pereg, Lily

2012-01-01

Australian Subtropical White Syndrome (ASWS) is an infectious, temperature dependent disease of the subtropical coral Turbinaria mesenterina involving a hitherto unknown transmissible causative agent. This report describes significant changes in the coral associated bacterial community as the disease progresses from the apparently healthy tissue of ASWS affected coral colonies, to areas of the colony affected by ASWS lesions, to the dead coral skeleton exposed by ASWS. In an effort to better understand the potential roles of bacteria in the formation of disease lesions, the effect of antibacterials on the rate of lesion progression was tested, and both culture based and culture independent techniques were used to investigate the bacterial communities associated with colonies of T. mesenterina. Culture-independent analysis was performed using the Oligonucleotide Fingerprinting of Ribosomal Genes (OFRG) technique, which allowed a library of 8094 cloned bacterial 16S ribosomal genes to be analysed. Interestingly, the bacterial communities associated with both healthy and disease affected corals were very diverse and ASWS associated communities were not characterized by a single dominant organism. Treatment with antibacterials had a significant effect on the rate of progress of disease lesions (p = 0.006), suggesting that bacteria may play direct roles as the causative agents of ASWS. A number of potential aetiological agents of ASWS were identified in both the culture-based and culture-independent studies. In the culture-independent study an Alphaproteobacterium closely related to Roseovarius crassostreae, the apparent aetiological agent of juvenile oyster disease, was found to be significantly associated with disease lesions. In the culture-based study Vibrio harveyi was consistently associated with ASWS affected coral colonies and was not isolated from any healthy colonies. The differing results of the culture based and culture-independent studies highlight the

The role of coral-associated bacterial communities in Australian Subtropical White Syndrome of Turbinaria mesenterina.

Directory of Open Access Journals (Sweden)

Scott Godwin

Full Text Available Australian Subtropical White Syndrome (ASWS is an infectious, temperature dependent disease of the subtropical coral Turbinaria mesenterina involving a hitherto unknown transmissible causative agent. This report describes significant changes in the coral associated bacterial community as the disease progresses from the apparently healthy tissue of ASWS affected coral colonies, to areas of the colony affected by ASWS lesions, to the dead coral skeleton exposed by ASWS. In an effort to better understand the potential roles of bacteria in the formation of disease lesions, the effect of antibacterials on the rate of lesion progression was tested, and both culture based and culture independent techniques were used to investigate the bacterial communities associated with colonies of T. mesenterina. Culture-independent analysis was performed using the Oligonucleotide Fingerprinting of Ribosomal Genes (OFRG technique, which allowed a library of 8094 cloned bacterial 16S ribosomal genes to be analysed. Interestingly, the bacterial communities associated with both healthy and disease affected corals were very diverse and ASWS associated communities were not characterized by a single dominant organism. Treatment with antibacterials had a significant effect on the rate of progress of disease lesions (p = 0.006, suggesting that bacteria may play direct roles as the causative agents of ASWS. A number of potential aetiological agents of ASWS were identified in both the culture-based and culture-independent studies. In the culture-independent study an Alphaproteobacterium closely related to Roseovarius crassostreae, the apparent aetiological agent of juvenile oyster disease, was found to be significantly associated with disease lesions. In the culture-based study Vibrio harveyi was consistently associated with ASWS affected coral colonies and was not isolated from any healthy colonies. The differing results of the culture based and culture-independent studies

Pharmacological, ethnopharmacological, and botanical evaluation of subtropical medicinal plants of Lower Kheng region in Bhutan.

Science.gov (United States)

Wangchuk, Phurpa; Yeshi, Karma; Jamphel, Kinga

2017-12-01

The Bhutanese Sowa Rigpa medicine (BSM) uses medicinal plants as the bulk ingredients. Our study was to botanically identify subtropical medicinal plants from the Lower Kheng region in Bhutan, transcribe ethnopharmacological uses, and highlight reported pharmacological activities of each plant. We freely listed the medicinal plants used in the BSM literature, current formulations, and the medicinal plants inventory documents. This was followed by a survey and the identification of medicinal plants in the Lower Kheng region. The botanical identification of each medicinal plant was confirmed using The Plant List , eFloras , and TROPICOS . Data mining for reported pharmacological activities was performed using Google Scholar, Scopus, PubMed, and SciFinder Scholar. We identified 61 subtropical plants as the medicinal plants used in BSM. Of these, 17 plants were cultivated as edible plant species, 30 species grow abundantly, 24 species grow in moderate numbers, and only seven species were scarce to find. All these species grow within the altitude range of 100-1800 m above sea level. A total of 19 species were trees, and 13 of them were shrubs. Seeds ranked first in the parts usage category. Goshing Gewog (Block) hosted maximum number of medicinal plants. About 52 species have been pharmacologically studied and only nine species remain unstudied. Lower Kheng region is rich in subtropical medicinal plants and 30 species present immediate economic potential that could benefit BSM, Lower Kheng communities and other Sowa Rigpa practicing organizations.

Reconstructing Holocene (sub)tropical climate and cyclone variability using geochemical proxies

OpenAIRE

van Soelen, E.E.

2012-01-01

Anthropogenic greenhouse gas emissions are responsible for a warming trend that cannot easily be reversed. This warming trend is expected to have a large impact on global weather patterns and local environmental conditions, for example by changing precipitation patterns, sea level rise and increasing tropical cyclone activity. Therefore, (sub)tropical coastal regions are expected to be heavily impacted by future climate change. To improve our understanding of the possible consequences of futu...

Coral reef ecosystem marine protected area monitoring in Fagamalo, American Samoa: benthic images collected during belt transect surveys in 2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In 2010 the village of Fagamalo, Tutuila, American Samoa, designated a no-take Marine Protected Area that sees the protection of 2.25 square kilometers of ocean....

Iodine monoxide in the north subtropical free troposphere [Discussion paper

OpenAIRE

Puentedura, Olga; Gil-Ojeda, Manuel; Saiz-Lopez, Alfonso; Hay, Tim; Navarro Comas, Mónica; Gómez Peláez, Ángel Jesús; Cuevas Agulló, Emilio; Iglesias, J.

2011-01-01

Iodine monoxide (IO) was retrieved using a new multi-axis DOAS instrument deployed at the Izaña subtropical observatory as part of the Network for the Detection of Atmospheric Composition Change (NDACC) programme. The station is located at 2370 m a.s.l., well above the trade wind inversion that limits the top of the marine boundary layer, and is hence representative of the free troposphere. We report daily observations from May to August 2010 at different viewing angles. During this period, t...

Single-Column Model Simulations of Subtropical Marine Boundary-Layer Cloud Transitions Under Weakening Inversions

NARCIS (Netherlands)

Neggers, R.A.J.; Ackerman, Andrew S.; Angevine, W. M.; Bazile, Eric; Beau, I.; Blossey, P. N.; Boutle, I. A.; de Bruijn, C.; cheng, A; van der Dussen, J.J.; Fletcher, J.; Dal Gesso, S.; Jam, A.; Kawai, H; Cheedela, S. K.; Larson, V. E.; Lefebvre, Marie Pierre; Lock, A. P.; Meyer, N. R.; de Roode, S.R.; de Rooy, WC; Sandu, I; Xiao, H; Xu, K. M.

2017-01-01

Results are presented of the GASS/EUCLIPSE single-column model intercomparison study on the subtropical marine low-level cloud transition. A central goal is to establish the performance of state-of-the-art boundary-layer schemes for weather and climate models for this cloud regime, using

Forest Type and Tree Characteristics Determine the Vertical Distribution of Epiphytic Lichen Biomass in Subtropical Forests

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Su Li

2017-11-01

Full Text Available Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens were quantified on 73 whole trees in five forest types in Southwest China to clarify the vertical stratification of their biomass in subtropical forests. Lichen biomass was significantly influenced by forest type and host attributes, varying from 187.11 to 8.55 g∙tree−1 among forest types and from 289.81 to <0.01 g∙tree−1 among tree species. The vertical stratification of lichen biomass was also determined by forest type, which peaked at the top in primary Lithocarpus forest and middle-aged oak secondary forest and in the middle upper heights in other forests. Overall, the proportion of lichen biomass accounted for 73.17–100.00% of total lichen biomass on branches and 0.00–26.83% on trunks in five forests, and 64.53–100.00% and 0.00–35.47% on eight host species. Seven functional groups showed marked and various responses to tree height between and among forest types. This information improves our understanding of the distribution of epiphytic lichens in forest ecosystems and the promotion of forest management in subtropical China.

Elevated UV-B radiation increased the decomposition of Cinnamomum camphora and Cyclobalanopsis glauca leaf litter in subtropical China

Energy Technology Data Exchange (ETDEWEB)

Song, Xinzhang Z.; Zhang, Huiling L.; Jiang, Hong; Yu, Shuquan Q. [Zhejiang Agriculture and Forestry Univ., Lin' an (China). The Nurturing Station for the State Key Lab. of Subtropical Silviculture; Zhejiang Agriculture and Forestry Univ., Lin' an (China). Zhejiang Provincial Key Lab. of Carbon Cycling and Carbon Sequestration in Forest Ecosystems; Chang, Scott X. [Alberta Univ., Edmonton (Canada). Dept. of Renewable Resources; Peng, Changhui H. [Quebec Univ., Montreal (Canada). Inst. of Environment Sciences

2012-03-15

Ultraviolet-B (UV-B) radiation reaching the earth's surface has been increasing due to ozone depletion and can profoundly influence litter decomposition and nutrient cycling in terrestrial ecosystems. The role of UV-B radiation in litter decomposition in humid environments is poorly understood; we thus investigated the effect of UV-B radiation on litter decomposition and nitrogen (N) release in a humid subtropical ecosystem in China. We conducted a field-based experiment using the litterbag method to study litter decomposition and N release under ambient and elevated (31% above ambient) UV-B radiation, using the leaf litter of two common tree species, Cinnamomum camphora and Cyclobalanopsis glauca, native to subtropical China. Elevated UV-B radiation significantly increased the decomposition rate of C. camphora and C. glauca leaf litter by 16.7% and 27.8%, respectively, and increased the N release from the decomposing litter of C. glauca but not C. camphora. Elevated UV-B radiation significantly accelerated the decomposition of litter of two native tree species and the N release from the decomposition litter of C. glauca in humid subtropical China, which has implications for soil carbon flux and forest productivity. (orig.)

Lineage-specific late pleistocene expansion of an endemic subtropical gossamer-wing damselfly, Euphaea formosa, in Taiwan

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Huang Jen-Pan

2011-04-01

Full Text Available Abstract Background Pleistocene glacial oscillations have significantly affected the historical population dynamics of temperate taxa. However, the general effects of recent climatic changes on the evolutionary history and genetic structure of extant subtropical species remain poorly understood. In the present study, phylogeographic and historical demographic analyses based on mitochondrial and nuclear DNA sequences were used. The aim was to investigate whether Pleistocene climatic cycles, paleo-drainages or mountain vicariance of Taiwan shaped the evolutionary diversification of a subtropical gossamer-wing damselfly, Euphaea formosa. Results E. formosa populations originated in the middle Pleistocene period (0.3 Mya and consisted of two evolutionarily independent lineages. It is likely that they derived from the Pleistocene paleo-drainages of northern and southern Minjiang, or alternatively by divergence within Taiwan. The ancestral North-central lineage colonized northwestern Taiwan first and maintained a slowly growing population throughout much of the early to middle Pleistocene period. The ancestral widespread lineage reached central-southern Taiwan and experienced a spatial and demographic expansion into eastern Taiwan. This expansion began approximately 30,000 years ago in the Holocene interglacial period. The ancestral southern expansion into eastern Taiwan indicates that the central mountain range (CMR formed a barrier to east-west expansion. However, E. formosa populations in the three major biogeographic regions (East, South, and North-Central exhibit no significant genetic partitions, suggesting that river drainages and mountains did not form strong geographical barriers against gene flow among extant populations. Conclusions The present study implies that the antiquity of E. formosa's colonization is associated with its high dispersal ability and larval tolerance to the late Pleistocene dry grasslands. The effect of late Pleistocene

Excess winter mortality and cold temperatures in a subtropical city, Guangzhou, China.

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Chun-Quan Ou

Full Text Available BACKGROUND: A significant increase in mortality was observed during cold winters in many temperate regions. However, there is a lack of evidence from tropical and subtropical regions, and the influence of ambient temperatures on seasonal variation of mortality was not well documented. METHODS: This study included 213,737 registered deaths from January 2003 to December 2011 in Guangzhou, a subtropical city in Southern China. Excess winter mortality was calculated by the excess percentage of monthly mortality in winters over that of non-winter months. A generalized linear model with a quasi-Poisson distribution was applied to analyze the association between monthly mean temperature and mortality, after controlling for other meteorological measures and air pollution. RESULTS: The mortality rate in the winter was 26% higher than the average rate in other seasons. On average, there were 1,848 excess winter deaths annually, with around half (52% from cardiovascular diseases and a quarter (24% from respiratory diseases. Excess winter mortality was higher in the elderly, females and those with low education level than the young, males and those with high education level, respectively. A much larger winter increase was observed in out-of-hospital mortality compared to in-hospital mortality (45% vs. 17%. We found a significant negative correlation of annual excess winter mortality with average winter temperature (rs=-0.738, P=0.037, but not with air pollution levels. A 1 °C decrease in monthly mean temperature was associated with an increase of 1.38% (95% CI:0.34%-2.40% and 0.88% (95% CI:0.11%-1.64% in monthly mortality at lags of 0-1 month, respectively. CONCLUSION: Similar to temperate regions, a subtropical city Guangzhou showed a clear seasonal pattern in mortality, with a sharper spike in winter. Our results highlight the role of cold temperature on the winter mortality even in warm climate. Precautionary measures should be strengthened to mitigate

Analyzing the efficacy of subtropical urban forests in offsetting carbon emissions from cities

Science.gov (United States)

Francisco Escobedo; Sebastian Varela; Min Zhao; John E. Wagner; Wayne Zipperer

2010-01-01

Urban forest management and policies have been promoted as a tool to mitigate carbon dioxide (CO2) emissions. This study used existing CO2 reduction measures from subtropical Miami-Dade and Gainesville, USA and modeled carbon storage and sequestration by trees to analyze policies that use urban forests to offset carbon emissions. Field data were analyzed, modeled, and...

76 FR 18419 - Movement of Hass Avocados From Areas Where Mediterranean Fruit Fly or South American Fruit Fly Exist

Science.gov (United States)

2011-04-04

... where the infested avocados were grown will immediately be suspended from the export program until an... Avocados From Areas Where Mediterranean Fruit Fly or South American Fruit Fly Exist AGENCY: Animal and... certain restrictions regarding the movement of fresh Hass variety avocados. Specifically, we are proposing...

Decadal Drought and Wetness Reconstructed for Subtropical North America in the Mexican Drought Atlas

Science.gov (United States)

Burnette, D. J.; Stahle, D. W.; Cook, E. R.; Villanueva Diaz, J.; Griffin, D.; Cook, B.

2014-12-01

A new drought atlas has been developed for subtropical North America, including the entire Republic of Mexico. This Mexican Drought Atlas (MXDA) is based on 251 tree-ring chronologies, including 82 from Mexico and another 169 from the southern U.S. and western Guatemala. Point-by-point principal components regression was used to reconstruct the self-calibrating Palmer Drought Severity Index (PDSI) for June-August. Calibration and verification statistics were improved over what was previously possible with the North American Drought Atlas, which was based on fewer chronologies only in Mexico. The MXDA will be served on the web with analytical tools for composite, correlation, and congruence analyses. The new PDSI reconstructions provide a more detailed estimation of decadal moisture regimes over the past 2000 years, but are most robust after 1400 AD, when several chronologies are available across Mexico. Droughts previously identified in a subset of chronologies are confirmed and their spatial impact quantified in the new reconstructions. This includes the intense drought of the mid-15th Century described in Aztec legend, the 16th Century megadrought, and "El Año del Hambre", one of the worst famines in Mexican history. We also use the best replicated portion of the MXDA in the 18th and 19th Centuries to reconstruct moisture anomalies during key time periods of Mexican turmoil (e.g., the Mexican War of Independence).

Facilitation influences patterns of perennial species abundance and richness in a subtropical dune system.

Science.gov (United States)

Dalotto, Cecilia E S; Sühs, Rafael B; Dechoum, Michele S; Pugnaire, Francisco I; Peroni, Nivaldo; Castellani, Tânia T

2018-04-01

Positive interactions in plant communities are under-reported in subtropical systems most likely because they are not identified as stressful environments. However, environmental factors or disturbance can limit plant growth in any system and lead to stressful conditions. For instance, salinity and low nutrient and water availability generate a gradient of stressful conditions in coastal systems depending on distance to shore. In a tropical coastal system in SE Brazil, we aimed to assess whether Guapira opposita , a shrub common in restinga environments, acted as nurse involved in ecological succession and which factors influenced its facilitation process. We sampled perennial species above 10 cm in height under the canopy of 35 G. opposita individuals and in neighbouring open areas. Shrub height, canopy area and distance to freshwater bodies were measured in the field, and distance to the ocean was obtained from aerial images. In addition, we measured the distance to the closest forest patch as a potential source of seeds. Plant abundance and species richness were higher under the canopy of G. opposita than in open areas. Facilitation by G. opposita was mainly determined by shrub height, which had a positive relationship with woody and bromeliads abundance and species richness while there was no relationship with the other factors. Overall, our data evidence that tropical environments may be highly stressful for plants and that nurse species play a key role in the regeneration of restinga environments, where their presence is critical to maintain ecosystem diversity and function.

Plants of the American continent with antimalarial activity

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Ingrid R. Mariath

Full Text Available Malaria is a human parasitic disease caused by protozoa species of the Plasmodium genus. This disease has affected populations of the tropical and subtropical regions. About 500 million new cases occur annually on the world and therefore it is considered an emerging disease of important public health problem. In this context, the natural products as vegetables species have their bioactive molecules as targets for pharmacological, toxicological and phytochemical studies towards the development of more effective medicines for the treatment of many diseases. So this work intends to aid the researchers in the study of natural products to the treatment of malaria. In this review, 476 plants of the American continent were related for the antimalarial activity and of these vegetables species 198 were active and 278 inactive for some type of Plasmodium when they were evaluated through of in vitro or in vivo bioassays models.

Biogeography of azooxanthellate corals in the Caribbean and surrounding areas

Science.gov (United States)

Dawson, J.

2002-04-01

Biogeographic patterns for azooxanthellate corals are not as well known as those of zooxanthellate (primarily reef-building) corals. I analyzed occurrences of 129 species of azooxanthellate corals in 19 geopolitical regions in the Caribbean and surrounding areas. I performed an unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis using Bray-Curtis' similarity measure on the complete data set and shallow- and deep-water subsets of the data. The results indicate two provinces, each with a widespread (tropical and subtropical distributions) component to its fauna. One province has a tropical and primarily insular component to it, while the other has a subtropical and primarily continental component. By contrast, zooxanthellate corals have a uniform faunal composition throughout the Caribbean. Moreover, zooxanthellate corals have half as many species in the Caribbean as the azooxanthellate corals even though their global diversities are equal. These differences in diversity and geographic distribution patterns should be considered when developing conservation strategies.

A comparative assessment of heavy metal accumulation in soft parts and byssus of mussels from subarctic, temperate, subtropical and tropical marine environments

International Nuclear Information System (INIS)

Szefer, P.; Fowler, S.W.; Ikuta, K.; Osuna, F. Paez; Ali, A.A.; Kim, B.-S.; Fernandes, H.M.; Belzunce, M.-J.; Guterstam, B.; Kunzendorf, H.; Wolowicz, M.; Hummel, H.; Deslous-Paoli, M.

2006-01-01

Existing data on metal concentrations in mussels from subarctic, temperate, subtropical and tropical waters were analyzed using multivariate statistics in order to assess regional variations in metal contamination. Potential errors were reduced by only analyzing data from surveys that employed the same protocols, analytical methodologies and analysts. Factor analysis demonstrated that mussels inhabiting extremely contaminated areas (e.g. from Japanese and Swedish metallurgy sources) could be separated from mussels from other contaminated areas, and that metals such as Cd, Pb, Cu and Zn could be used to identify heavily contaminated samples while Co, Fe, Cr and Ni concentrations were good markers for exposure to inputs from different industrial sources. Furthermore byssus, like soft tissue, selectively and sensitively reflects variations of certain metal concentrations in ambient waters and thus serves as a reliable biomonitor for these contaminants in a variety of coastal and estuarine areas. - Byssus of mytilids, like soft tissues can be used as efficient biomonitor for heavy metals in the marine environment

A comparative assessment of heavy metal accumulation in soft parts and byssus of mussels from subarctic, temperate, subtropical and tropical marine environments

Energy Technology Data Exchange (ETDEWEB)

Szefer, P. [Department of Food Sciences, Medical University of Gdansk, Al. Gen. J. Hallera 107, PL 80-416 Gdansk (Poland)]. E-mail: pszef@amg.gda.pl; Fowler, S.W. [IAEA Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 (Monaco); Ikuta, K. [Laboratory of Aquatic Environment and Ecology, Department of Fisheries, Faculty of Agriculture, Miyazaki University, 889-21 Miyazaki (Japan); Osuna, F. Paez [Institute of Marine Sciences and Limnology, Mazatlan Station, National Autonomous University of Mexico, Mazatlan 82000, Sinaloa (Mexico); Ali, A.A. [Faculty of Science, Arts and Education, University of Aden, PO Box 6014, Khormaksar, Aden (Yemen); Kim, B.-S. [School of Earth and Environmental Science, Seoul National University, 56-1 Shillimdong, 151-742 (Korea, Republic of); Fernandes, H.M. [Instituto de Radioprotecao e Dosimetria, Cz. Postal 37 750 - CEP: 22642-970, Rio de Janeiro (Brazil); Belzunce, M.-J. [Instituto Tecnnologico Pesquero y Alimentario, Dpto de Oceanografia y Medio Ambiente Marino, Herrera Kaia, Portualdea z/g, 20110 Pasaia (Gipuzkoa) (Spain); Guterstam, B. [Stensund Ecological Center, 61991 Trosa, Sweden and Global Water Partnership Secretariat, Hantverkargatan 5, SE-112 21 Stockholm (Sweden); Kunzendorf, H. [Gamma Dating Center (GDC), Institute of Geography, University of Copenhagen, Oster Voldgage 10 DK-1350 Copenhagen K (Denmark); Wolowicz, M. [Laboratory of Estuarine Ecology, Institute of Oceanography, University of Gdansk, Al. Pilsudskiego 46, 81-378, Gdynia (Poland); Hummel, H. [Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology, Korringaweg 7, 4401 NT Yerseke (Netherlands); Deslous-Paoli, M. [IFREMER, Unite Ecologie Conchylicole, 1, rue Jean Vilar, 34200 Sete (France)

2006-01-15

Existing data on metal concentrations in mussels from subarctic, temperate, subtropical and tropical waters were analyzed using multivariate statistics in order to assess regional variations in metal contamination. Potential errors were reduced by only analyzing data from surveys that employed the same protocols, analytical methodologies and analysts. Factor analysis demonstrated that mussels inhabiting extremely contaminated areas (e.g. from Japanese and Swedish metallurgy sources) could be separated from mussels from other contaminated areas, and that metals such as Cd, Pb, Cu and Zn could be used to identify heavily contaminated samples while Co, Fe, Cr and Ni concentrations were good markers for exposure to inputs from different industrial sources. Furthermore byssus, like soft tissue, selectively and sensitively reflects variations of certain metal concentrations in ambient waters and thus serves as a reliable biomonitor for these contaminants in a variety of coastal and estuarine areas. - Byssus of mytilids, like soft tissues can be used as efficient biomonitor for heavy metals in the marine environment.

Potential for biotic resistance from herbivores to tropical and subtropical plant invasions in aquatic ecosystems

NARCIS (Netherlands)

Petruzella, A.; Grutters, B.M.C.; Thomaz, S.M.; Bakker, E.S.

2017-01-01

Invasions of tropical and subtropical aquatic plants threaten biodiversity and cause ecological and economic impacts worldwide. An urgent question is whether native herbivores are able to inhibit the spread of these alien species thus providing biotic resistance. The potential for biotic resistance

Water Level and Fire Regulate Carbon Sequestration in a Subtropical Peat Marsh

Science.gov (United States)

Graham, S.; Sumner, D.; Shoemaker, B.; Benscoter, B.; Hinkle, C. R.

2014-12-01

Managed wetlands provide valuable ecosystem services, including carbon storage. Management practices, such as water-level manipulation and prescribed fire, can have a profound effect on the carbon dynamics of these ecosystems. Fluxes of carbon dioxide have been measured by eddy covariance methods over a subtropical peat marsh in Florida, USA since 2009. During this 5-year period, the site has experienced hydroperiods ranging from nine to twelve months. Hydroperiod was found to affect net ecosystem productivity, which was relatively low (70-130 grams carbon per square meter) in years with periodic drying events and much higher (300-600 grams carbon per square meter) during years with constant marsh inundation. The site experienced a prescribed fire in Spring of 2014, which consumed approximately 80% of the aboveground biomass (800 grams carbon per square meter). In addition to the carbon released by the fire, photosynthetic uptake during what would normally be the most productive part of the year was reduced relative to previous years due to low leaf area. These results illustrate how management practices can affect carbon sequestration, which is important for both atmospheric greenhouse gas concentrations and maintenance of peat topography.

Maintenance of a living understory enhances soil carbon sequestration in subtropical orchards.

Science.gov (United States)

Liu, Zhanfeng; Lin, Yongbiao; Lu, Hongfang; Ding, Mingmao; Tan, Yaowen; Xu, Shejin; Fu, Shenglei

2013-01-01

Orchard understory represents an important component of the orchards, performing numerous functions related to soil quality, water relations and microclimate, but little attention has been paid on its effect on soil C sequestration. In the face of global climate change, fruit producers also require techniques that increase carbon (C) sequestration in a cost-effective manner. Here we present a case study to compare the effects of understory management (sod culture vs. clean tillage) on soil C sequestration in four subtropical orchards. The results of a 10-year study indicated that the maintenance of sod significantly enhanced the soil C stock in the top 1 m of orchard soils. Relative to clean tillage, sod culture increased annual soil C sequestration by 2.85 t C ha(-1), suggesting that understory management based on sod culture offers promising potential for soil carbon sequestration. Considering that China has the largest area of orchards in the world and that few of these orchards currently have sod understories, the establishment and maintenance of sod in orchards can help China increase C sequestration and greatly contribute to achieving CO2 reduction targets at a regional scale and potentially at a national scale.

Relating land use patterns to stream nutrient levels in red soil agricultural catchments in subtropical central China.

Science.gov (United States)

Wang, Yi; Li, Yong; Liu, Xinliang; Liu, Feng; Li, Yuyuan; Song, Lifang; Li, Hang; Ma, Qiumei; Wu, Jinshui

2014-09-01

Land use has obvious influence on surface water quality; thus, it is important to understand the effects of land use patterns on surface water quality. This study explored the relationships between land use patterns and stream nutrient levels, including ammonium-N (NH4 (+)-N), nitrate-N (NO3 (-)-N), total N (TN), dissolved P (DP), and total P (TP) concentrations, in one forest and 12 agricultural catchments in subtropical central China. The results indicated that the TN concentrations ranged between 0.90 and 6.50 mg L(-1) and the TP concentrations ranged between 0.08 and 0.53 mg L(-1), showing that moderate nutrient pollution occurred in the catchments. The proportional areal coverages of forests, paddy fields, tea fields, residential areas, and water had distinct effects on stream nutrient levels. Except for the forest, all studied land use types had a potential to increase stream nutrient levels in the catchments. The land use pattern indices at the landscape level were significantly correlated to N nutrients but rarely correlated to P nutrients in stream water, whereas the influence of the land use pattern indices at the class level on stream water quality differentiated among the land use types and nutrient species. Multiple regression analysis suggested that land use pattern indices at the class level, including patch density (PD), largest patch index (LPI), mean shape index (SHMN), and mean Euclidian nearest neighbor distance (ENNMN), played an intrinsic role in influencing stream nutrient quality, and these four indices explained 35.08 % of the variability of stream nutrient levels in the catchments (pstream nutrient pollution in subtropical central China.

Precipitation and temperature drive seasonal variation in bioaccumulation of polycyclic aromatic hydrocarbons in the planktonic food webs of a subtropical shallow eutrophic lake in China.

Science.gov (United States)

Tao, Yuqiang; Yu, Jing; Xue, Bin; Yao, Shuchun; Wang, Sumin

2017-04-01

Hydrophobic organic contaminants (HOCs) are toxic and ubiquitous in aquatic environments and pose great risks to aquatic organisms. Bioaccumulation by plankton is the first step for HOCs to enter aquatic food webs. Trophic status is considered to dominate variations in bioaccumulation of HOCs in plankton in temperate and frigid deep oligotrophic waters. However, long-term driving factors for bioaccumulation of HOCs in planktonic food webs of subtropical shallow eutrophic waters have not been well investigated. China has the largest subtropical lake density in the Northern Hemisphere. Due to limited field data, long-term variations in the bioaccumulation of HOCs in these lakes are almost unknown. Here we take Lake Xuanwu as an example to investigate long-term variations in the bioaccumulation, and biomagnification of polycyclic aromatic hydrocarbon (PAHs) in planktonic food webs of subtropical shallow eutrophic lakes in China, and elucidate the driving factors. Our results indicate that temperature rather than nutrients dominates long-term dynamics of planktonic biomass in this lake. Precipitation significantly enhances the concentrations of the PAHs, and total suspended particles, and consequently affects the distribution of the PAHs in the water column. Biomass dilution induced by temperature dominates bioaccumulation of the PAHs by both phytoplankton and zooplankton (copepods and cladocerans). Biomagnification of the PAHs from phytoplankton to zooplankton is positively correlated with temperature. Our study suggests that temperature and precipitation drive long-term variations in the bioaccumulation of the PAHs in the planktonic food webs of this subtropical shallow eutrophic lake. Lake Xuanwu has a similar mean annual temperature, annual precipitation, sunshine duration, and nutrient levels as other subtropical shallow eutrophic lakes in China. This study may also help to understand the bioaccumulation of HOCs in planktonic food webs of other subtropical shallow

Reproductive Performance of Arabian and Thoroughbred Mares under Subtropical Conditions of Pakistan.

Science.gov (United States)

Warriach, H M; Memon, M A; Ahmad, N; Norman, S T; Ghafar, A; Arif, M

2014-07-01

Breeding records of 57 Arabian and 66 Thoroughbred mares were analysed to assess their reproductive performance under the subtropical conditions of Pakistan. The Arabian mares showed significantly higher conception rates (p500±32 days) was significantly (psummer (June to August) months. Age of mares affected the conception rates, as mares at ages 3 to 7 and 8 to 12 years of ages had significantly higher conception rates (psummer months.

Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins.

Science.gov (United States)

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Harris, Willie G; Xuan, Zhemin

2012-01-01

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L and decreases in nitrate nitrogen (NO-N) from 2.7 mg L to soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0-7.8 mg L), resulting in NO-N of 1.3 to 3.3 mg L in shallow groundwater. Enrichment of δN and δO of NO combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO transport beneath the sandy basin. Soil-extractable NO-N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO impacts. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Comparison of stream nutrient conditions in a subtropical lowland watershed to EPA suggested criteria

Science.gov (United States)

April Mason; Y. Jun Xu; Johnny M. Grace

2007-01-01

Nutrients such as nitrogen, phosphorus and organic carbon are essential to the health and diversity of stream ecosystems. However, excess nutrients can cause eutrophication, resulting in overgrowth of aquatic plants and decline of the ecosystem diversity. A paired-watershed study was initiated in a subtropical forested watershed within the Ouachita River Basin in...

Enhanced or Weakened Western North Pacific Subtropical High under Global Warming?

OpenAIRE

He, Chao; Zhou, Tianjun; Lin, Ailan; Wu, Bo; Gu, Dejun; Li, Chunhui; Zheng, Bin

2015-01-01

The Western North Pacific Subtropical High (WNPSH) regulates East Asian climate in summer. Anomalous WNPSH causes floods, droughts and heat waves in China, Japan and Korea. The potential change of the WNPSH under global warming is concerned by Asian people, but whether the WNPSH would be enhanced or weakened remains inconclusive. Based on the multi-model climate change projection from the 5th phase of Coupled Model Intercomparison Project (CMIP5), we show evidences that the WNPSH tends to wea...

Rainfall declines over Queensland from 1951-2007 and links to the Subtropical Ridge and the SAM

International Nuclear Information System (INIS)

Cottrill, D A; Ribbe, J

2010-01-01

Much of southern and eastern Australia including Queensland have experienced rainfall declines over recent decades affecting agricultural production and accelerating water infrastructure development. Rainfall declines from southern Australia have now been directly related to changes in the Southern Annular Mode (SAM) and the subtropical ridge. In southern and coastal Queensland, the rainfall declines have occurred mostly in the austral summer and autumn. Observations from this region reveal the rainfall decline is correlated to an increase in the mean sea level pressure (MSLP) at many stations. The largest increases in MSLP are over southeast Queensland and coastal regions, where some of the largest rainfall declines occur. This study indicates the subtropical ridge as one of the main factors in the rainfall decline over this region. SAM is also likely to be important, although its seasonal influence, apart from winter, is harder to determine.

Repeated range expansions and inter-/postglacial recolonization routes of Sargentodoxa cuneata (Oliv.) Rehd. et Wils. (Lardizabalaceae) in subtropical China revealed by chloroplast phylogeography.

Science.gov (United States)

Tian, Shuang; Lei, Shu-Qing; Hu, Wan; Deng, Ling-Li; Li, Bo; Meng, Qing-Lin; Soltis, Douglas E; Soltis, Pamela S; Fan, Deng-Mei; Zhang, Zhi-Yong

2015-04-01

Most plant phylogeographic studies in subtropical China have stressed the importance of multiple refugia and limited admixture among refugia. Little attention has been paid to range expansion and recolonization routes in this region. In this study, we implemented a phylogeographic survey on Sargentodoxa cuneata, a widespread woody deciduous climber in subtropical China to determine if it conforms to the expansion-contraction (EC) model during the Pleistocene. Sequence variation of two chloroplast intergenic spacers (IGSs) in 369 individuals from 54 populations of S. cuneata was examined. Twenty-six chloroplast haplotypes were recovered. One of these (H5) occurred across the range of S. cuneata and was absent from only 13 populations. Sixteen of the 26 haplotypes were connected to H5 by one mutation and displayed a star-like pattern in the haplotype network. All chloroplast haplotypes clustered into two lineages (A and B) in a Bayesian tree, and most haplotypes (18 out of 26) originated during the mid-Pleistocene (0.63-1.07Ma). Demographic analyses detected a recent range expansion that occurred at 95.98ka (CI: 61.7-112.53ka) for Lineage A. The genetic signature of an ancient range expansion after the Middle Pleistocene Transition (MPT) was also evident. Three recolonization routes were identified in subtropical China. The results suggest that temperate plants in subtropical China may conform to the EC model to some extent. However, the genetic signature from multiple historical processes may complicate the phylogeographic patterns of organisms in the region due to the mild Pleistocene climate. This study provides a new perspective for understanding the evolutionary history of temperate plants in subtropical China. Copyright © 2015 Elsevier Inc. All rights reserved.

Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India

Directory of Open Access Journals (Sweden)

Fenella Mary War Nongkhlaw

2014-12-01

Full Text Available The present study was aimed to investigate the endophytic and epiphytic bacteria associated with selected ethnomedicinal plants from the pristine subtropical forests of Meghalaya and analyse them for plant growth promotion and antagonistic ability. This study is an attempt to explore plant associated bacteria which are beneficial to host plants, and thus aid in the conservation of ethnomedicinal plants of the studied subtropical forests, which are dwindling due to exploitation. The plant growth promotion parameters like indole acetic acid (IAA production, mineral phosphate solubilisation, acid phosphatase activity, presence of 1-aminocyclopropane-1-carboxylic acid deaminase (ACC gene, nitrogen fixation, cellulose digestion, chitin and pectin degradation were screened among the isolates. The study revealed significant differences in bacterial population not only between the epiphytic and endophytic microhabitats, but also amongst the host plants. Out of the 70 isolated plant associated bacteria, Bacillus sp., Serratia sp., Pseudomonas sp., Pantoea sp., and Lysinibacillus sp. showed potent plant growth promotion properties. Bacillus siamensis C53 and B. subtilis cenB showed significant antagonistic activity against the tested pathogens. This study indicated the isolates inhabiting the plants prevalent in the subtropical sacred forests could be explored for use as plant growth promoters while practising the cultivation and conservation of ethnomedicinal plants. Rev. Biol. Trop. 62 (4: 1295-1308. Epub 2014 December 01.

Subtropical Low Cloud Response to a Warmer Climate in an Superparameterized Climate Model: Part I. Regime Sorting and Physical Mechanisms

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Peter N Blossey

2009-07-01

Full Text Available The subtropical low cloud response to a climate with SST uniformly warmed by 2 K is analyzed in the SP- CAM superparameterized climate model, in which each grid column is replaced by a two-dimensional cloud-resolving model (CRM. Intriguingly, SP-CAM shows substantial low cloud increases over the subtropical oceans in the warmer climate. The paper aims to understand the mechanism for these increases. The subtropical low cloud increase is analyzed by sorting grid-column months of the climate model into composite cloud regimes using percentile ranges of lower tropospheric stability (LTS. LTS is observed to be well correlated to subtropical low cloud amount and boundary layer vertical structure. The low cloud increase in SP-CAM is attributed to boundary-layer destabilization due to increased clear-sky radiative cooling in the warmer climate. This drives more shallow cumulus convection and a moister boundary layer, inducing cloud increases and further increasing the radiative cooling. The boundary layer depth does not change substantially, due to compensation between increased radiative cooling (which promotes more turbulent mixing and boundary-layer deepening and slight strengthening of the boundary-layer top inversion (which inhibits turbulent entrainment and promotes a shallower boundary layer. The widespread changes in low clouds do not appear to be driven by changes in mean subsidence.
In a companion paper we use column-mode CRM simulations based on LTS-composite profiles to further study the low cloud response mechanisms and to explore the sensitivity of low cloud response to grid resolution in SP-CAM.

Native American plant resources in the Yucca Mountain Area, Nevada

International Nuclear Information System (INIS)

Stoffle, R.W.; Evans, M.J.; Halmo, D.B.

1989-11-01

This report presents Native American interpretations of and concerns for plant resources on or near Yucca Mountain, Nevada. This one of three research reports regarding Native American cultural resources that may be affected by site characterization activities related to the Yucca Mountain high-level radioactive waste disposal facility. Representatives of the sixteen involved American Indian tribes identified and interpreted plant resources as part of a consultation relationship between themselves and the US Department of Energy (DOE). Participants in the ethnobotany studies included botanists who have conducted, and continue to conduct, botanical studies for the Yucca Mountain Project. This report is to be used to review research procedures and findings regarding the process of consulting with the sixteen tribes, interviews with tribal plant specialists and elders, and findings from the ethnobotanical visits with representatives of the sixteen tribes. An annual report will include a chapter that summarizes the key findings from this plant resources study. 23 refs., 75 figs., 39 tabs

Native American plant resources in the Yucca Mountain Area, Nevada

Energy Technology Data Exchange (ETDEWEB)

Stoffle, R.W.; Evans, M.J.; Halmo, D.B. [Michigan Univ., Ann Arbor, MI (USA). Inst. for Social Research; Niles, W.E.; O`Farrell, J.T. [EG and G Energy Measurements, Inc., Goleta, CA (USA)

1989-11-01

This report presents Native American interpretations of and concerns for plant resources on or near Yucca Mountain, Nevada. This one of three research reports regarding Native American cultural resources that may be affected by site characterization activities related to the Yucca Mountain high-level radioactive waste disposal facility. Representatives of the sixteen involved American Indian tribes identified and interpreted plant resources as part of a consultation relationship between themselves and the US Department of Energy (DOE). Participants in the ethnobotany studies included botanists who have conducted, and continue to conduct, botanical studies for the Yucca Mountain Project. This report is to be used to review research procedures and findings regarding the process of consulting with the sixteen tribes, interviews with tribal plant specialists and elders, and findings from the ethnobotanical visits with representatives of the sixteen tribes. An annual report will include a chapter that summarizes the key findings from this plant resources study. 23 refs., 75 figs., 39 tabs.

Variability and trend in ozone over the southern tropics and subtropics

Science.gov (United States)

Toihir, Abdoulwahab Mohamed; Portafaix, Thierry; Sivakumar, Venkataraman; Bencherif, Hassan; Pazmiño, Andréa; Bègue, Nelson

2018-03-01

Long-term variability in ozone trends was assessed over eight Southern Hemisphere tropical and subtropical sites (Natal, Nairobi, Ascension Island, Java, Samoa, Fiji, Reunion and Irene), using total column ozone data (TCO) and vertical ozone profiles (altitude range 15-30 km) recorded during the period January 1998-December 2012. The TCO datasets were constructed by combination of satellite data (OMI and TOMS) and ground-based observations recorded using Dobson and SAOZ spectrometers. Vertical ozone profiles were obtained from balloon-sonde experiments which were operated within the framework of the SHADOZ network. The analysis in this study was performed using the Trend-Run model. This is a multivariate regression model based on the principle of separating the variations of ozone time series into a sum of several forcings (annual and semi-annual oscillations, QBO (Quasi-Biennial Oscillation), ENSO, 11-year solar cycle) that account for most of its variability. The trend value is calculated based on the slope of a normalized linear function which is one of the forcing parameters included in the model. Three regions were defined as follows: equatorial (0-10° S), tropical (10-20° S) and subtropical (20-30° S). Results obtained indicate that ozone variability is dominated by seasonal and quasi-biennial oscillations. The ENSO contribution is observed to be significant in the tropical lower stratosphere and especially over the Pacific sites (Samoa and Java). The annual cycle of ozone is observed to be the most dominant mode of variability for all the sites and presents a meridional signature with a maximum over the subtropics, while semi-annual and quasi-biannual ozone modes are more apparent over the equatorial region, and their magnitude decreases southward. The ozone variation mode linked to the QBO signal is observed between altitudes of 20 and 28 km. Over the equatorial zone there is a strong signal at ˜ 26 km, where 58 % ±2 % of total ozone variability is

Intensificación de la circulación atmosférica meridional en la región subtropical de América del sur inferida a partir de registros dendroclimatológicos

Directory of Open Access Journals (Sweden)

1998-01-01

áticas en el subtrópico y establecer sus relaciones con los cambios en la circulación atmosférica a nivel continental. INTENSIFICATION OF MERIDIONAL CIRCULATION IN THE SOUTH AMERICAN SUBTROPICS INFERRED FROM TREE-RING RECORDS. The main goal of this study is to show the use of tree-ring records to properly characterize the climatic changes which have affected the South American subtropics during the past two centuries. Tree-ring width chronologies from nogal criollo (Juglans australis and cedro tucumano (Cedrela lilloi have been used to estimate regional changes in temperature and precipitation since 1800. Similar to instrumental records, precipitation-sensitive chronologies indicate a steady increase of precipitation in the subtropics starting around 1950. This precipitation increase is unprecedented in the 200-year long tree-ring records. The mean sea-level pressure (MSLP gradient between the tropics and subtropics, measured as the differences in MSLP between Cuiabá (15° S and Reconquista (29° S, shows a increase since about 1950. This intensification of the pressure gradient, together with an increase in temperatures at the subtropics, appears to have induced a southward shift of the continental low pressure cell over South America. This southward displacement of the low pressure cell may have increased precipitation and reduced the extent of the dry season in the subtropics. Spatial correlation patterns between tree rings and sea-surface temperatures (SST indicate that subtropical precipitation changes may also be related to a steady increase in SST in the South Atlantic during the past four decades. These results consistently show the large potential of tree-ring records to reconstruct climatic variations in the subtropics and to establish the relationships between regional climate and large-scale climatic forcing.

The role of tropical cyclones in precipitation over the tropical and subtropical North America

Science.gov (United States)

Dominguez, Christian; Magaña, Victor

2018-03-01

Tropical cyclones (TCs) are essential elements of the hydrological cycle in tropical and subtropical regions. In the present study, the contribution of TCs to seasonal precipitation around the tropical and subtropical North America is examined. When TC activity over the tropical eastern Pacific (TEP) or the Intra Americas Seas (IAS) is below (above-normal), regional precipitation may be below (above-normal). However, it is not only the number of TCs what may change seasonal precipitation, but the trajectory of the systems. TCs induce intense precipitation over continental regions if they are close enough to shorelines, for instance, if the TC center is located, on average, less than 500 km-distant from the coast. However, if TCs are more remote than this threshold distance, the chances of rain over continental regions decrease, particularly in arid and semi-arid regions. In addition, a distant TC may induce subsidence or produce moisture divergence that inhibits, at least for a few days, convective activity farther away than the threshold distance. An analysis of interannual variability in the TCs that produce precipitation over the tropical and subtropical North America shows that some regions in northern Mexico, which mostly depend on this effect to undergo wet years, may experience seasonal negative anomalies in precipitation if TCs trajectories are remote. Therefore, TCs (activity and trajectories) are important modulators of climate variability on various time scales, either by producing intense rainfall or by inhibiting convection at distant regions from their trajectory. The impact of such variations on water availability in northern Mexico may be relevant, since water availability in dams recovers under the effects of TC rainfall. Seasonal precipitation forecasts or climate change scenarios for these regions should take into account the effect of TCs, if regional adaptation strategies are implemented.

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1997-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. At ANSTO, a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional dispersion and deposition data to determine the dose to man via the major pathways of external and internal irradiation. The external irradiation data will need to include lifestyle information such as time spent L indoors/outdoors, the high/low activity times of the different groups of people (especially critical groups) and shielding factors for housing. The internal irradiation data requires food consumption values, effect of food processing and transfer parameters (soil to plant, plant to animal) to be obtained for tropical and sub-tropical regions. The model allows the user to specify the radionuclide of interest, the age of the person receiving l the dose, race, dietary components and lifestyle. The operator may use a number of default categories, but regional information may also be entered and incorporated into the radiological model allowing assessment of dose to critical groups using site specific data. Initially, the model will deal with the South East Asian region but flexibility has been incorporated into the design to allow application in other regions. A geographic information system is used for display of all input and output data allowing quick access to not only the results but also the underlying assumptions. The model also has portability across computer platforms. The model has been developed to provide a tool for directing future research, has application as a planing tool for emergency response operations but its priority lies in understanding the behaviour of radionuclides in the tropical and sub-tropical environments and their effect on humankind

Atlanta ariejansseni, a new species of shelled heteropod from the Southern Subtropical Convergence Zone (Gastropoda, Pterotracheoidea)

NARCIS (Netherlands)

Wall-Palmer, D.; Burridge, A.K.; Peijnenburg, K.T.C.A.

2016-01-01

The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics: a systematic literature review.

NARCIS (Netherlands)

Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

Aim: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This paper reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. Method: Global health databases were searched in three

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review

NARCIS (Netherlands)

Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

AIM: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. METHOD: Global health databases were searched in three

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1998-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. The information used in these models pertains mostly to temperate and cold climate data, with these data mostly being hard-wired into the body of the model. At the Australian Nuclear Science and Technology Organisation (ANSTO), a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional data (South East Asia) with transfer parameters (soil to plant, plant to animal) obtained for tropical and sub-tropical regions. Flexibility has been incorporated into the the design of the model to allow application in other regions. Where the relevant data are not available, default temperate data are used whilst specific research will be initiated to determine the information required. A Geographic Information System (GIS) is used for the display of input and output data allowing quick access to not only the results but also to the underlying assumptions

Application of the operative once-for-all dressing kits in subtropical zone after radio-disinfection

International Nuclear Information System (INIS)

Dai Tingen; Sun Sujin; Wang Genchun; Wan Jian; Luo Xuelin; Wang Haiqiao; Tang Dongxu

1988-01-01

After irradiation with 10.0 - 20.0 kGy, the sterilized dressing kits have been found to be reliable, safe and without and side effect in field operation in subtropical ambient. They were used in 175 cases, altogether 1347 times. They are very useful for the field operations

Performance analysis of solar air cooled double effect LiBr/H2O absorption cooling system in subtropical city

International Nuclear Information System (INIS)

Li, Zeyu; Ye, Xiangyang; Liu, Jinping

2014-01-01

Highlights: • The meteorological data during the working period of air conditioning was measured. • The suitable working range of collector temperature of system was gotten. • The characteristic of hourly and monthly total efficiency of system were obtained. • The yearly performance of system was calculated. - Abstract: Due to the absence of cooling tower and independent on water, the air cooled solar double effect LiBr/H 2 O absorption cooling system is more convenient to be used in commercial building and household use. The performance with collector temperature is an important field for such system. The paper mainly deals with the performance with collector temperature for the solar air cooled double effect LiBr/H 2 O absorption cooling system in subtropical city. The parameters of system are: aperture area of collector array is 27 m 2 , tilted angle of collector with respect to the horizontal plane is 20 toward to south evaporator temperature is 5 °C and the cooling capacity is 20 kW. The simulation is based on the meteorological data of monthly typical day which was summarized from a year round measured data. A corresponding parametric model was developed. The hourly and average performance with the collector temperature for monthly typical day was obtained and discussed. It was found that the suitable working range of inlet temperature of collector is 110–130 °C to improve performance and lower the risk of crystallization. The difference of hourly total efficiency in 9:00–16:00 is less, and the monthly total efficiency from May to October is approximate. The yearly performance of system including total efficiency, cooling capacity per area of collector and solar fraction was given. Furthermore, the effect of effectiveness of heat exchanger and pressure drop on total efficiency and solar fraction was studied and compared. The paper can serve as a preliminary investigation of solar air cooled double effect LiBr/H 2 O absorption cooling system in

Woody Floristic Composition, Size Class Distribution and spatial Pattern of a Subtropical Lowland Rainforest at Nanjen Lake, Southernmost Taiwan

Directory of Open Access Journals (Sweden)

Su-Wei Fan

2005-12-01

Full Text Available A permanent 2.21 ha plot of lowland subtropical rainforest was established at Nanjen Lake of the Nanjenshan Nature Reserve in southern Taiwan. All free-standing woody plants in the plot with DBH  1 cm were identified, measured, tagged, and mapped. A total of 120 tree species (21,592 stems, belonging to 44 families and 83 genera, was recorded. The community structure was characterized by a relative dominance of Castanopsis carlesii in the canopy, Illicium arborescens in the subcanopy, and Psychotria rubra in the understory. The dominant families were Fagaceae, Illiciaceae, Aquifoliaceae, Lauraceae and Theaceae. However, typical species of lowland area in Taiwan, such as members of Euphorbiaceae and Moraceae, were relatively rare. Thus, floristic composition of this area was comparable with that found in some of the subtropical rain forests or even warm-temperate rain forests of the Central Range in Taiwan. The analysis of size-class distributions of individual species showed good recruitment patterns with a rich sapling bank for each species. TWINSPAN analysis revealed four distinct groups of samples, with the ridge top and northwest streamside plant communities representing two opposite extremes of the gradient. The dominant families of the ridge group were Fagaceae, Illiciaceae, Theaceae, Aquifoliaceae and Lauraceae, whereas those dominating the streamside group were Rubiaceae, Araliceae, Lauraceae, Fagaceae, and Staphyleaceae. Most species had a patchy distribution and many were distributed randomly. Among those with a patchy distribution, Cyclobalanopsis championii and Rhododendron simsii only occurred on the ridge top, while Drypetes karapinensis and Ficus fistulosa occurred along the streamside. Illicium arborescens and Ilex cochinchinensis were commonly distributed on the intermediate slope. Species that appeared to be randomly or near-randomly distributed over the plot included Schefflera octophylla and Daphniphyllum glaucescens ssp

Primary production and chlorophyll distributions in the subtropical and tropical waters of the Atlantic Ocean in the autumn of 2002

Science.gov (United States)

Vedernikov, V. I.; Gagarin, V. I.; Demidov, A. B.; Burenkov, V. I.; Stunzhas, P. A.

2007-06-01

In October and November 2002, high and relatively high values of the chlorophyll a concentration at the sea surface ( C chl) were observed in the English Channel (0.47 mg/m3), in the waters of the North Atlantic Current (0.25 mg/m3), in the tropical and subtropical anticyclonic gyres (0.07-0.42 mg/m3), and also in the southwestern region of the southern subtropical anticyclonic gyre (usually 0.11-0.23 mg/m3). The central regions of the southern subtropical anticyclonic gyre (SATG) and the North Atlantic tropical gyre (NATR) were characterized by lower values of C chl (0.02-0.08 mg/m3 for the SATG and 0.07-0.14 mg/m3 for the NATR). At most of the SATG stations, the values of the surface primary production ( C phs) varied from 2.5 to 5.5 mg C/m3 per day and were mainly defined by the fluctuations of C chl ( r = +0.78) rather than by those of the assimilation number ( r = +0.54). The low assimilation activity of phytoplankton in these waters (1.3-4.6 mg chl a per hour) pointed to a lack of nutrients. An analysis of the variability of their concentration and the composition of photosynthetic pigments showed that, in the waters north of 30° N, the growth of phytoplankton was mostly restricted by the deficiency of nitrogen, while, in more southern areas, at the majority of stations (about 60%), the phosphorus concentrations were the minimum. At the low concentrations of nitrates and nitrites, ammonium represented itself as a buffer that prevented planktonic algae from extreme degrees of nitric starvation. In the tropical waters and in the waters of the SATG, the primary production throughout the water column varied from 240 to 380 mg C/m2 30° per day. This level of productivity at stations with low values of C chl (photosynthesis based on in situ measurements point to the high efficiency of utilizing the penetrating solar radiation by phytoplankton on cloudy days.

Diet preferences of goats in a subtropical dry forest and implications for habitat management

Science.gov (United States)

Genie M. Fleming; Joseph Wunderle Jr.; David N. Ewert

2016-01-01

As part of an experimental study of using controlled goat grazing to manage winter habitat of the Kirtland’s warbler (Setophaga kirtlandii), an endangered Nearctic neotropical migratory bird, we evaluated diet preferences of domesticated goats within early successional subtropical dry forest in The Bahamas. We expected goats would show a low preference for two plants (...

Facilitation influences patterns of perennial species abundance and richness in a subtropical dune system

Science.gov (United States)

Dalotto, Cecilia E S; Sühs, Rafael B; Dechoum, Michele S; Pugnaire, Francisco I; Peroni, Nivaldo; Castellani, Tânia T

2018-01-01

Abstract Positive interactions in plant communities are under-reported in subtropical systems most likely because they are not identified as stressful environments. However, environmental factors or disturbance can limit plant growth in any system and lead to stressful conditions. For instance, salinity and low nutrient and water availability generate a gradient of stressful conditions in coastal systems depending on distance to shore. In a tropical coastal system in SE Brazil, we aimed to assess whether Guapira opposita, a shrub common in restinga environments, acted as nurse involved in ecological succession and which factors influenced its facilitation process. We sampled perennial species above 10 cm in height under the canopy of 35 G. opposita individuals and in neighbouring open areas. Shrub height, canopy area and distance to freshwater bodies were measured in the field, and distance to the ocean was obtained from aerial images. In addition, we measured the distance to the closest forest patch as a potential source of seeds. Plant abundance and species richness were higher under the canopy of G. opposita than in open areas. Facilitation by G. opposita was mainly determined by shrub height, which had a positive relationship with woody and bromeliads abundance and species richness while there was no relationship with the other factors. Overall, our data evidence that tropical environments may be highly stressful for plants and that nurse species play a key role in the regeneration of restinga environments, where their presence is critical to maintain ecosystem diversity and function. PMID:29644027

Rapid structural and compositional change in an old-growth subtropical forest: using plant traits to identify probable drivers.

Science.gov (United States)

Malizia, Agustina; Easdale, Tomás A; Grau, H Ricardo

2013-01-01

Recent studies have shown directional changes in old-growth tropical forests, but changes are complex and diverse, and their drivers unclear. Here, we report rapid net structural and compositional changes in an old-growth subtropical forest and we assess the functional nature of these changes to test hypothetical drivers including recovery from past disturbances, reduction in ungulate browsing, CO2 fertilization, and increases in rainfall and temperature. The study relies on 15 years of demographic monitoring within 8 ha of subtropical montane forest in Argentina. Between 1992 and 2007, stem density markedly increased by 50% (12 stems ha(-1) y(-1)) and basal area by 6% (0.13 m(2) ha(-1) y(-1)). Increased stem density resulted from enhanced recruitment of understory treelets (Piper tucumanum, Eugenia uniflora, Allophylus edulis) into small size classes. Among 27 common tree species, net population growth was negatively correlated with maximum tree size and longevity, and positively correlated with leaf size and leaf nutrient content, especially so when initial population size was controlled for. Changes were inconsistent with predictions derived from past disturbances (no increase in shade-tolerant or long-lived late-succesional species), rainfall or temperature increase (no increase in evergreen or deciduous species, respectively). However, the increase in nutrient-rich soft-leaved species was consistent with exclusion of large herbivores two decades before monitoring started; and CO2 fertilization could help explain the disproportionate increase in small stems. Reductions in populations of large vertebrates have been observed in many otherwise undisturbed tropical forests, and our results suggest they can have important structural and functional repercussions in these forests.

Satellite Detection of Orographic Gravity-wave Activity in the Winter Subtropical Stratosphere over Australia and Africa

Science.gov (United States)

Eckermann, S. D.; Wu, D. L.

2012-01-01

Orographic gravity-wave (OGW) parameterizations in models produce waves over subtropical mountain ranges in Australia and Africa that propagate into the stratosphere during austral winter and deposit momentum, affecting weather and climate. Satellite sensors have measured stratospheric GWs for over a decade, yet find no evidence of these waves. So are parameterizations failing here? Here we argue that the short wavelengths of subtropical OGWs place them near or below the detection limits of satellite sensors. To test this hypothesis, we reanalyze nine years of stratospheric radiances from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite during austral winter, applying new averaging techniques to maximize signal-to-noise and improve thresholds for OGW detection. Deep climatological enhancements in stratospheric OGW variance over specific mountain ranges in Australia and southern Africa are revealed for the first time, which exhibit temporal and vertical variations consistent with predicted OGW responses to varying background winds.

Effects of imidacloprid on the ecology of sub-tropical freshwater microcosms.

Science.gov (United States)

Sumon, Kizar Ahmed; Ritika, Afifat Khanam; Peeters, Edwin T H M; Rashid, Harunur; Bosma, Roel H; Rahman, Md Shahidur; Fatema, Mst Kaniz; Van den Brink, Paul J

2018-05-01

The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Increasing potential for intense tropical and subtropical thunderstorms under global warming.

Science.gov (United States)

Singh, Martin S; Kuang, Zhiming; Maloney, Eric D; Hannah, Walter M; Wolding, Brandon O

2017-10-31

Intense thunderstorms produce rapid cloud updrafts and may be associated with a range of destructive weather events. An important ingredient in measures of the potential for intense thunderstorms is the convective available potential energy (CAPE). Climate models project increases in summertime mean CAPE in the tropics and subtropics in response to global warming, but the physical mechanisms responsible for such increases and the implications for future thunderstorm activity remain uncertain. Here, we show that high percentiles of the CAPE distribution (CAPE extremes) also increase robustly with warming across the tropics and subtropics in an ensemble of state-of-the-art climate models, implying strong increases in the frequency of occurrence of environments conducive to intense thunderstorms in future climate projections. The increase in CAPE extremes is consistent with a recently proposed theoretical model in which CAPE depends on the influence of convective entrainment on the tropospheric lapse rate, and we demonstrate the importance of this influence for simulated CAPE extremes using a climate model in which the convective entrainment rate is varied. We further show that the theoretical model is able to account for the climatological relationship between CAPE and a measure of lower-tropospheric humidity in simulations and in observations. Our results provide a physical basis on which to understand projected future increases in intense thunderstorm potential, and they suggest that an important mechanism that contributes to such increases may be present in Earth's atmosphere. Published under the PNAS license.

Facts about American Indian Education

Science.gov (United States)

American Indian College Fund, 2010

2010-01-01

As a result of living in remote rural areas, American Indians living on reservations have limited access to higher education. One-third of American Indians live on reservations, according to the U.S. Census Bureau. According to the most recent U.S. government statistics, the overall poverty rate for American Indians/Alaska Natives, including…

SEASONAL VARIATIONS IN HUMAN PAROTID FLUID FLOW RATE IN A SUBTROPICAL CLIMATE.

Science.gov (United States)

Parotid fluid was collected under conditions of very minimal stimulation from 3,868 systemically healthy young adult males over a period of two...calendar years. The study was carried out in a subtropical climate in which the only thermal discomfort resulted from the summer heat. Parotid flow rate...fall. During the summer months the mean rate of parotid flow was 0.031 ml./minute; during the winter the flow rate mean increased by 35% to 0.042 ml

Study of Subtropical Forestry Index Retrieval Using Terrestrial Laser Scanning and Hemispherical Photography

Directory of Open Access Journals (Sweden)

Ting Yun

2015-01-01

Full Text Available In order to retrieve gap fraction, leaf inclination angle, and leaf area index (LAI of subtropical forestry canopy, here we acquired forestry detailed information by means of hemispherical photography, terrestrial laser scanning, and LAI-2200 plant canopy analyzer. Meanwhile, we presented a series of image processing and computer graphics algorithms that include image and point cloud data (PCD segmentation methods for branch and leaf classification and PCD features, such as normal vector, tangent plane extraction, and hemispherical projection method for PCD coordinate transformation. In addition, various forestry mathematical models were proposed to deduce forestry canopy indexes based on the radiation transfer model of Beer-Lambert law. Through the comparison of the experimental results on many plot samples, the terrestrial laser scanner- (TLS- based index estimation method obtains results similar to digital hemispherical photograph (HP and LAI-2200 plant canopy analyzer taken of the same stands and used for validation. It indicates that the TLS-based algorithm is able to capture the variability in LAI of forest stands with a range of densities, and there is a high chance to enhance TLS as a calibration tool for other devices.

Condiciones medias de invierno y ondas cuasi-estacionarias de Rossby asociadas a la frecuencia invernal de noches frias y cálidas en Argentina subtropical Mean winter conditions and quasi-stationary Rossby waves associated with the winter frequency of warm and cold nights in subtropical Argentina

Directory of Open Access Journals (Sweden)

Eduardo A Agosta

2012-12-01

nights (TN10 and warm nights (TN90 during winter (JJA over subtropical Argentina, to the north of 40°S and surrounding areas (ASA from meteorological stations and NCEP/DOE AMIP-II and ECMWF ERA-interim reanalysis data. It is found that the frequency of warm nights (Tmin over percentile 90, TN90 is modulated at interannual scales by quasi-stationary wave propagation induced by convection anomalies in the Indic and Pacific. The high frequency of warm nights is associated with anomalous warming over the central equatorial Pacific (positive phase of El Niño-Southern Oscillation, ENSO. The low frequency of warm nights is linked to anomalous convection over the monsoon Indian area and the western tropical southern Indic. Hence quasi-stationary Rossby wave activity propagation is favored over the Indic, Pacific and southern South America. Such a teleconnection favors in turn the high fequency of cold nights (Tmin below percentile 10, TN10. Instead, the low frequency of cold nights is linked to the low-frequency variability of the Southern Hemisphere high-latitude mode (SAM. It is found that winters with high (low frequency of cold (warm nights are characterized by a strengthening (weakening of the subtropical jet over southern South America and adjacent areas. The current remote forcings are related with atmospheric/oceanic processes that are interconnected at seasonal-interseasonal scales, which could allow us to develop statistical-dynamical forecasts for the higher or lower occurrence of warm or cold nights in winter.

Integrated studies of a regional ozone pollution synthetically affected by subtropical high and typhoon system in the Yangtze River Delta region, China

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L. Shu

2016-12-01

Full Text Available Severe high ozone (O3 episodes usually have close relations to synoptic systems. A regional continuous O3 pollution episode was detected over the Yangtze River Delta (YRD region in China during 7–12 August 2013, in which the O3 concentrations in more than half of the cities exceeded the national air quality standard. The maximum hourly concentration of O3 reached 167.1 ppb. By means of the observational analysis and the numerical simulation, the characteristics and the essential impact factors of the typical regional O3 pollution are comprehensively investigated. The observational analysis shows that the atmospheric subsidence dominated by the western Pacific subtropical high plays a crucial role in the formation of high-level O3. The favorable weather conditions, such as extremely high temperature, low relative humidity and weak wind speed, caused by the abnormally strong subtropical high are responsible for the trapping and the chemical production of O3 in the boundary layer. In addition, when the YRD cities are at the front of Typhoon Utor, the periphery circulation of typhoon system can enhance the downward airflows and cause worse air quality. However, when the typhoon system weakens the subtropical high, the prevailing southeasterly surface wind leads to the mitigation of the O3 pollution. The integrated process rate (IPR analysis incorporated in the Community Multi-scale Air Quality (CMAQ model is applied to further illustrate the combined influence of subtropical high and typhoon system in this O3 episode. The results show that the vertical diffusion (VDIF and the gas-phase chemistry (CHEM are two major contributors to O3 formation. During the episode, the contributions of VDIF and CHEM to O3 maintain the high values over the YRD region. On 10–12 August, the cities close to the sea are apparently affected by the typhoon system, with the contribution of VDIF increasing to 28.45 ppb h−1 in Shanghai and 19.76 ppb h−1 in

American cutaneous leishmaniasis in dogs from an endemic urban area in Cianorte municipality, Paraná State, Brazil

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DA Cerino

2010-01-01

Full Text Available American cutaneous leishmaniasis (ACL was investigated in dogs from an urban endemic area in Cianorte, Paraná state, Brazil. Of 169 studied dogs, none presented suspected ACL lesions. Eleven animals (6.6% had anti-Leishmania braziliensis antibodies (titers > 40 detected by the immunofluorescent antibody test (IFAT while four (2.4% showed L. braziliensis-complex DNA by the polymerase chain reaction (PCR. Although no associations were found between IFAT or PCR results and age, sex, origin, free-roaming animals or length of residence at the address, the majority of IFAT- or PCR-positive dogs were from the urban area of the city and were allowed to roam freely beyond their neighborhood. The presence of anti-Leishmania braziliensis antibodies and L. braziliensis-complex DNA in dogs from this urban area near a native-forest park indicates the importance of following up on these dogs to confirm the ACL diagnosis.

Macrobioerosion in Porites corals in subtropical northern South China Sea: a limiting factor for high-latitude reef framework development

Science.gov (United States)

Chen, Tianran; Li, Shu; Yu, Kefu

2013-03-01

Bioerosion is an important limiting factor in carbonate accretion and reef framework development; however, few studies have quantified the direct impact of macroborers on high-latitude coral communities, which are viewed as potential refuge during a period of global warming. In this study, internal macrobioerosion of Porites corals was examined at Daya Bay, subtropical northern South China Sea. The principal borers were the bivalve Lithophaga spp. and the sponges Cliona spp. and Cliothosa spp. (≥80 %), while sipunculid and polychaete worms and barnacles accounted for small amounts of bioerosion (≤20 %). Porites corals were heavily bioeroded in areas impacted by aquacultural and urban activities (10.34-27.55 %) compared with corals in relatively unpolluted areas (2.18-6.76 %). High levels of bioerosion, especially boring bivalve infestation, significantly weaken the corals and increase their susceptibility to dislodgement and fragmentation in typhoons, limiting accumulation of limestone framework. This study implies that carbonate accretion and reef development for high-latitude coral communities may be limited in future high-CO2 and eutrophication-stressed environments.

Changes in Photosystem Ⅱ Activity and Leaf Reflectance Features of Several Subtropical Woody Plants Under Simulated SO2 Treatment

Institute of Scientific and Technical Information of China (English)

Nan Liu; Chang-Lian Peng; Zhi-Fang Lin; Gui-Zhu Lin; Ling-Ling Zhang; Xiao-Ping Pan

2006-01-01

The effects of simulated SO2 treatment on the photosynthetic apparatus were investigated in five subtropical forest plants, namely Pinus massoniana Lamb., Schima superba Gardn. et Champ., Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., Acmena acuminatissima (BI.) Merr et Perry, and Cryptocarya concinna Hance. After leaf sections had been immersed in 0, 20, 50, and 100 mmol/L NaHSO3 for 20 h, total chlorophyll (Chl) content, Chl a/b, maximal photochemical efficiency, and the photochemical quantum yields of photosystem Ⅱ of all five woody plants were reduced to different degrees, whereas lutein content (Chl base) was increased. Two protective mechanisms, namely the xanthophyll cycle (de-epoxidation) and an anti-oxidant system (1,1-diphenyl-2-picrylhydrazyl radical-scavenging capacity), showed differences in the degree of modulation under simulated SO2 treatment. Compared with control (distilled water treatment), the revised normalized difference vegetation index, a leaf reflectance index, was lowered with increasing concentrations of NaHSO3. Cryptocarya concinna, a dominant species in the late succession stage of subtropical forests in South China, exhibited less sensitivity to NaHSO3. Conversely, Pinus massoniana, the pioneer heliophyte species, was most susceptible to NaHSO3 treatment. It is suggested that SO2 pollution may accelerate the succession of subtropical forest.

Preliminary comparison of different immune and production components in local and imported Saanen goats reared under a sub-tropical environment.

Science.gov (United States)

Barbour, Elie K; Itani, Houssam H; Sleiman, Fawwak T; Saade, Maya F; Harakeh, Steve; Nour, Afif M Abdel; Shaib, Houssam A

2012-01-01

Three objectives were included in this research work. The first objective compared different immune components in healthy mature males, mature females, and female kids of local and imported Saanen goats, reared under a sub-tropical environment. The significantly differing immune components were the blood monocyte percent, blood CD8 count, and the total white blood cell count. The second objective compared the performance of Saanen versus local does. The means of the milk yield and prolificacy of the imported Saanen does were significantly higher than those of the local does (pgoats on protection potential against prevalent diseases in the sub-tropical zone of the eastern Mediterranean countries is discussed.

Abundance and ecological implications of microplastic debris in the North Pacific Subtropical Gyre

OpenAIRE

Goldstein, Miriam Chanita

2012-01-01

Plastic pollution in the North Pacific Subtropical Gyre (NPSG), dubbed the "Great Pacific Garbage Patch," has been the subject of substantial public concern. However, there is relatively limited scientific understanding of how microplastic affects pelagic ecosystems. The motivation for this dissertation is to provide scientific information on the extent and impact of microplastic in the NPSG. The dissertation is organized around two central questions : 1) What are the abundance, distribution,...

Microbial community diversity in the gut of the South American termite Cornitermes cumulans (Isoptera: Termitidae).

Science.gov (United States)

Grieco, Maria Angela B; Cavalcante, Janaina J V; Cardoso, Alexander M; Vieira, Ricardo P; Machado, Ednildo A; Clementino, Maysa M; Medeiros, Marcelo N; Albano, Rodolpho M; Garcia, Eloi S; de Souza, Wanderley; Constantino, Reginaldo; Martins, Orlando B

2013-01-01

Termites inhabit tropical and subtropical areas where they contribute to structure and composition of soils by efficiently degrading biomass with aid of resident gut microbiota. In this study, culture-independent molecular analysis was performed based on bacterial and archaeal 16S rRNA clone libraries to describe the gut microbial communities within Cornitermes cumulans, a South American litter-feeding termite. Our data reveal extensive bacterial diversity, mainly composed of organisms from the phyla Spirochaetes, Bacteroidetes, Firmicutes, Actinobacteria, and Fibrobacteres. In contrast, a low diversity of archaeal 16S rRNA sequences was found, comprising mainly members of the Crenarchaeota phylum. The diversity of archaeal methanogens was further analyzed by sequencing clones from a library for the mcrA gene, which encodes the enzyme methyl coenzyme reductase, responsible for catalyzing the last step in methane production, methane being an important greenhouse gas. The mcrA sequences were diverse and divided phylogenetically into three clades related to uncultured environmental archaea and methanogens found in different termite species. C. cumulans is a litter-feeding, mound-building termite considered a keystone species in natural ecosystems and also a pest in agriculture. Here, we describe the archaeal and bacterial communities within this termite, revealing for the first time its intriguing microbiota.

Variability and trend in ozone over the southern tropics and subtropics

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A. M. Toihir

2018-03-01

Full Text Available Long-term variability in ozone trends was assessed over eight Southern Hemisphere tropical and subtropical sites (Natal, Nairobi, Ascension Island, Java, Samoa, Fiji, Reunion and Irene, using total column ozone data (TCO and vertical ozone profiles (altitude range 15–30 km recorded during the period January 1998–December 2012. The TCO datasets were constructed by combination of satellite data (OMI and TOMS and ground-based observations recorded using Dobson and SAOZ spectrometers. Vertical ozone profiles were obtained from balloon-sonde experiments which were operated within the framework of the SHADOZ network. The analysis in this study was performed using the Trend-Run model. This is a multivariate regression model based on the principle of separating the variations of ozone time series into a sum of several forcings (annual and semi-annual oscillations, QBO (Quasi-Biennial Oscillation, ENSO, 11-year solar cycle that account for most of its variability. The trend value is calculated based on the slope of a normalized linear function which is one of the forcing parameters included in the model. Three regions were defined as follows: equatorial (0–10° S, tropical (10–20° S and subtropical (20–30° S. Results obtained indicate that ozone variability is dominated by seasonal and quasi-biennial oscillations. The ENSO contribution is observed to be significant in the tropical lower stratosphere and especially over the Pacific sites (Samoa and Java. The annual cycle of ozone is observed to be the most dominant mode of variability for all the sites and presents a meridional signature with a maximum over the subtropics, while semi-annual and quasi-biannual ozone modes are more apparent over the equatorial region, and their magnitude decreases southward. The ozone variation mode linked to the QBO signal is observed between altitudes of 20 and 28 km. Over the equatorial zone there is a strong signal at  ∼ 26�

Mercury dynamics and mass balance in a subtropical forest, southwestern China

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M. Ma

2016-04-01

Full Text Available The mid-subtropical forest area in southwest China was affected by anthropogenic mercury (Hg emissions over the past 3 decades. We quantified mercury dynamics on the forest field and measured fluxes and pools of Hg in litterfall, throughfall, stream water and forest soil in an evergreen broadleaved forest field in southwestern China. Total Hg (THg input by the throughfall and litterfall was assessed at 32.2 and 42.9 µg m−2 yr−1, respectively, which was remarkably higher than those observed from other forest fields in the background of North America and Europe. Hg fluxes across the soil–air interface (18.6 mg m−2 yr−1 and runoff and/or stream flow (7.2 µg m−2 yr−1 were regarded as the dominant ways for THg export from the forest field. The forest field hosts an enormous amount of atmospheric Hg, and its reserves is estimated to be 25 341 µg m2. The ratio of output to input Hg fluxes (0.34 is higher compared with other study sites. The higher output / input ratio may represent an important ecological risk for the downstream aquatic ecosystems, even if the forest field could be an effective sink of Hg.

Isoprene Emission Factors for Subtropical Street Trees for Regional Air Quality Modeling.

Science.gov (United States)

Dunn-Johnston, Kristina A; Kreuzwieser, Jürgen; Hirabayashi, Satoshi; Plant, Lyndal; Rennenberg, Heinz; Schmidt, Susanne

2016-01-01

Evaluating the environmental benefits and consequences of urban trees supports their sustainable management in cities. Models such as i-Tree Eco enable decision-making by quantifying effects associated with particular tree species. Of specific concern are emissions of biogenic volatile organic compounds, particularly isoprene, that contribute to the formation of photochemical smog and ground level ozone. Few studies have quantified these potential disservices of urban trees, and current models predominantly use emissions data from trees that differ from those in our target region of subtropical Australia. The present study aimed (i) to quantify isoprene emission rates of three tree species that together represent 16% of the inventoried street trees in the target region; (ii) to evaluate outputs of the i-Tree Eco model using species-specific versus currently used, generic isoprene emission rates; and (iii) to evaluate the findings in the context of regional air quality. Isoprene emission rates of (Myrtaceae) and (Proteaceae) were 2.61 and 2.06 µg g dry leaf weight h, respectively, whereas (Sapindaceae) was a nonisoprene emitter. We substituted the generic isoprene emission rates with these three empirical values in i-Tree Eco, resulting in a 182 kg yr (97%) reduction in isoprene emissions, totaling 6284 kg yr when extrapolated to the target region. From these results we conclude that care has to be taken when using generic isoprene emission factors for urban tree models. We recommend that emissions be quantified for commonly planted trees, allowing decision-makers to select tree species with the greatest overall benefit for the urban environment. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effects of land cover change on litter decomposition and soil greenhouse gas fluxes in subtropical Hong Kong

Science.gov (United States)

Ngar Wong, Chun; Lai, Derrick Yuk Fo

2017-04-01

Nowadays, over 50% of the world's population live in urbanized areas and the level of urbanization varies substantially across countries. Intense human activities and management associated with urbanization can alter the microclimate and biogeochemical processes in urban areas, which subsequently affect the provision of ecosystem services and functions. Litter decomposition and soil greenhouse gas (GHG) exchange play an important role in governing nutrient cycling and future climate change, respectively. Yet, the effects of urbanization on these two biogeochemical processes remain uncertain and not well understood, especially in subtropical and high-density cities. This study aims to examine the effects of urbanization on decomposition and GHG fluxes among four land covers- natural forest, urban forest, farmland and roadside planter, in Hong Kong based on litterbag experiment and closed chamber measurements for one full year. Litter decomposition rate was significantly lower in farmland than in other land cover types. Significant differences in CO2 emission were detected among the four land cover types (pmean N2O fluxes, respectively. The emission of CO2 was positively correlated with soil potassium content, while CH4 and N2O flux increased markedly with soil temperature and nitrate nitrogen content, respectively. The results obtained in this study will enhance our understanding on urban ecosystem and be useful for recommending sustainable management strategies for conservation of ecosystem services in urban areas.

Mapping the occurrence of Chromolaena odorata (L.) in subtropical forest gaps using environmental and remote sensing data

CSIR Research Space (South Africa)

Malahlela, OE

2015-07-01

Full Text Available Globally, subtropical forests are rich in biodiversity. However, the native biodiversity in these forests is threatened by the presence of invasive species such as Chromolaena odorata (L.) King and Robinson, which thrives in forest canopy gaps. Our...

Effects of Hypoxia on the Phylogenetic Composition and Species Distribution of Protists in a Subtropical Harbor.

Science.gov (United States)

Rocke, Emma; Jing, Hongmei; Xia, Xiaomin; Liu, Hongbin

2016-07-01

Tolo Harbor, a subtropical semi-enclosed coastal water body, is surrounded by an expanding urban community, which contributes to large concentrations of nutrient runoff, leading to algal blooms and localized hypoxic episodes. Present knowledge of protist distributions in subtropical waters during hypoxic conditions is very limited. In this study, therefore, we combined parallel 454 pyrosequencing technology and denaturing gradient gel electrophoresis (DGGE) fingerprint analyses to reveal the protist community shifts before, during, and after a 2-week hypoxic episode during the summer of 2011. Hierarchical clustering for DGGE demonstrated similar grouping of hypoxic samples separately from oxic samples. Dissolved oxygen (DO) concentration and dissolved inorganic nitrogen:phosphate (DIN:PO4) concentrations significantly affected OTU distribution in 454 sequenced samples, and a shift toward a ciliate and marine alveolate clade II (MALV II) species composition occurred as waters shifted from oxic to hypoxic. These results suggest that protist community shifts toward heterotrophic and parasitic tendencies as well as decreased diversity and richness in response to hypoxic outbreaks.

Isolation and evaluation of oil-producing microalgae from subtropical coastal and brackish waters.

Directory of Open Access Journals (Sweden)

David K Y Lim

Full Text Available Microalgae have been widely reported as a promising source of biofuels, mainly based on their high areal productivity of biomass and lipids as triacylglycerides and the possibility for cultivation on non-arable land. The isolation and selection of suitable strains that are robust and display high growth and lipid accumulation rates is an important prerequisite for their successful cultivation as a bioenergy source, a process that can be compared to the initial selection and domestication of agricultural crops. We developed standard protocols for the isolation and cultivation for a range of marine and brackish microalgae. By comparing growth rates and lipid productivity, we assessed the potential of subtropical coastal and brackish microalgae for the production of biodiesel and other oil-based bioproducts. This study identified Nannochloropsis sp., Dunaniella salina and new isolates of Chlorella sp. and Tetraselmis sp. as suitable candidates for a multiple-product algae crop. We conclude that subtropical coastal microalgae display a variety of fatty acid profiles that offer a wide scope for several oil-based bioproducts, including biodiesel and omega-3 fatty acids. A biorefinery approach for microalgae would make economical production more feasible but challenges remain for efficient harvesting and extraction processes for some species.

Long-term trends of heat stress and energy use implications in subtropical climates

Energy Technology Data Exchange (ETDEWEB)

Lam, Joseph C.; Wan, Kevin K.W.; Wong, S.L.; Lam, Tony N.T. [Building Energy Research Group, Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR (China)

2010-02-15

Past and future trends of human comfort in terms of heat and cold stresses under the local subtropical climates using measured meteorological data as well as predictions from general climate models were investigated. Summer discomfort showed an increasing trend (and winter discomfort a decreasing trend) over the past 41 years from 1968 to 2008. Monthly mean minimum and maximum temperatures and moisture content predictions from a general climate model (MIROC3.2-H) were used to determine summer and winter discomfort for future years (2009-2100) based on two emissions scenarios B1 and A1B (low and medium forcing). The 92-year (2009-2100) mean cold stress would be reduced from the 41-year (1968-2008) mean value of 8.7 to about three for both emissions scenarios. The 92-year mean heat stress would be 115.9 and 120.6 for B1 and A1B, respectively, representing 31.6% and 36.9% increase over the 1968-2008 long-term average of 88.1. These suggest that the already small winter heating requirement in subtropical Hong Kong would become even more insignificant in future years, whereas the increasing trend of summer discomfort would result in more cooling demand in the built environment. (author)

Dynamics of Understory Shrub Biomass in Six Young Plantations of Southern Subtropical China

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Yuanqi Chen

2017-11-01

Full Text Available Understory shrubs are an important component of forest ecosystems and drive ecosystem processes, such as ecosystem carbon cycling. However, shrub biomass carbon stocks have rarely been reported, which limits our understanding of ecosystem C stock and cycling. In this study, we evaluated carbon accumulation of shrub species using allometric equations based on height and basal diameter in six subtropical plantations at the age of 1, 3, 4 and 6 years. The results showed that plantation type did not significantly affect the total biomass of shrubs, but it significantly affected the biomass of Rhodomyrtus tomentosa, Ilex asprella, Clerodendrum fortunatum and Baeckea frutescens. The biomass of dominant shrub species R. tomentosa, I. asprella, Gardenia jasminoides and Melastoma candidum increased with stand age, while the biomass of C. fortunatum and B. frutescens decreased. The inconsistent biomass-time patterns of different shrub species may be the primary reason for the altered total shrub biomass in each plantation. Consequently, we proposed that R. tomentosa, I. asprella, G. jasminoides and M. candidum could be preferable for understory carbon accumulation and should be maintained or planted because of their important functions in carbon accumulation and high economic values in the young plantations of southern subtropical China.

A Citizen Science Approach: A Detailed Ecological Assessment of Subtropical Reefs at Point Lookout, Australia.

Science.gov (United States)

Roelfsema, Chris; Thurstan, Ruth; Beger, Maria; Dudgeon, Christine; Loder, Jennifer; Kovacs, Eva; Gallo, Michele; Flower, Jason; Gomez Cabrera, K-le; Ortiz, Juan; Lea, Alexandra; Kleine, Diana

2016-01-01

Subtropical reefs provide an important habitat for flora and fauna, and proper monitoring is required for conservation. Monitoring these exposed and submerged reefs is challenging and available resources are limited. Citizen science is increasing in momentum, as an applied research tool and in the variety of monitoring approaches adopted. This paper aims to demonstrate an ecological assessment and mapping approach that incorporates both top-down (volunteer marine scientists) and bottom-up (divers/community) engagement aspects of citizen science, applied at a subtropical reef at Point Lookout, Southeast Queensland, Australia. Marine scientists trained fifty citizen scientists in survey techniques that included mapping of habitat features, recording of substrate, fish and invertebrate composition, and quantifying impacts (e.g., occurrence of substrate damage, presence of litter). In 2014 these volunteers conducted four seasonal surveys along semi-permanent transects, at five sites, across three reefs. The project presented is a model on how citizen science can be conducted in a marine environment through collaboration of volunteer researchers, non-researchers and local marine authorities. Significant differences in coral and algal cover were observed among the three sites, while fluctuations in algal cover were also observed seasonally. Differences in fish assemblages were apparent among sites and seasons, with subtropical fish groups observed more commonly in colder seasons. The least physical damage occurred in the most exposed sites (Flat Rock) within the highly protected marine park zones. The broad range of data collected through this top-down/bottom-up approach to citizen science exemplifies the projects' value and application for identifying ecosystem trends or patterns. The results of the project support natural resource and marine park management, providing a valuable contribution to existing scientific knowledge and the conservation of local reefs.

The role of the subtropical North Atlantic water cycle in recent US extreme precipitation events

Science.gov (United States)

Li, Laifang; Schmitt, Raymond W.; Ummenhofer, Caroline C.

2018-02-01

The role of the oceanic water cycle in the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies was much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.

On the occurrence of egg masses of the diamond-shaped squid Thysanoteuthis rhombus Troschel, 1857 in the subtropical eastern Atlantic (Canary Islands. A potential commercial species?

Directory of Open Access Journals (Sweden)

Alejandro Escanez

2012-09-01

Full Text Available Data on opportunistic sightings of diamond-shaped squid Thysanoteuthis rhombus egg masses in the Canary Islands (Atlantic Ocean are presented. A total of 16 egg masses of this species were recorded and photographed from 2000 to 2010 around the western islands of the archipelago (El Hierro, Tenerife and La Gomera. These data reveal the existence of an important spawning area for diamond-shaped squid around the Canary Islands, in subtropical east Atlantic waters. We provide preliminary data for the potential development of an artisanal fishery focused on this species, and a discussion on its potential impacts on the marine ecosystem.

Throughfall patterns of a Subtropical Atlantic Forest in Brazil

Science.gov (United States)

Macedo Sá, João Henrique; Borges Chaffe, Pedro Luiz; Yuimi de Oliveira, Debora; Nery Giglio, Joana; Kobiyama, Masato

2017-04-01

The interception process is responsible for the spatial and temporal redistribution of the precipitation that reaches the ground. This process is important especially in forested areas since it influences recycling of moisture from the air and also the amount of water that effectively reaches the ground. The contact of the precipitation with the canopy influences on the water quality, increasing the concentration of various nutrients in the throughfall (Tf) and stemflow (Sf). Brazil, only about 8% of the original Atlantic Forest cover remains. That is an important biome and little is known about the characteristics of rainfall interception of this forest. The total interception loss in forested areas is usually formulated as the gross precipitation (P) minus the sum of the throughfall (Tf) and the stemflow (Sf). The stems characteristics influence on Sf, meanwhile, the value of Tf strongly depends on the canopy and leaf structures. Because of the complex structure of the canopy, these characteristics are usually expressed by the simpler Leaf Area Index (LAI) or the Canopy Cover Fraction (CCF). The Araponga river experimental catchment (ARA) with 5.3 ha is on the northern plateau of Santa Catarina State, southern Brazil. It is an area completely covered by secondary subtropical Atlantic Forest, the regional climate is the Köppen Cfb type, i.e., temperate climate without dry season and with warm summer (the mean temperature of the hottest month is always under 22°C). The objectives of the present study were (i) to evaluate the spatial and temporal variation of canopy cover; (ii) to influence of the interception process on the precipitation quality; and (iii) to explore the relation between canopy cover and throughfall. Inside the catchment, 9 Tf gauges were installed 40 cm above the soil surface in order to include the interception by shrub. 28 hand-made gauges were installed on a circular area of 3 m radius to analyze the spatial variability of throughfall. During

Can small island mountains provide relief from the Subtropical Precipitation Decline? Simulating future precipitation regimes for small island nations using high resolution Regional Climate Models.

Science.gov (United States)

Bowden, J.; Terando, A. J.; Misra, V.; Wootten, A.

2017-12-01

Small island nations are vulnerable to changes in the hydrologic cycle because of their limited water resources. This risk to water security is likely even higher in sub-tropical regions where anthropogenic forcing of the climate system is expected to lead to a drier future (the so-called `dry-get-drier' pattern). However, high-resolution numerical modeling experiments have also shown an enhancement of existing orographically-influenced precipitation patterns on islands with steep topography, potentially mitigating subtropical drying on windward mountain sides. Here we explore the robustness of the near-term (25-45 years) subtropical precipitation decline (SPD) across two island groupings in the Caribbean, Puerto Rico and the U.S. Virgin Islands. These islands, forming the boundary between the Greater and Lesser Antilles, significantly differ in size, topographic relief, and orientation to prevailing winds. Two 2-km horizontal resolution regional climate model simulations are used to downscale a total of three different GCMs under the RCP8.5 emissions scenario. Results indicate some possibility for modest increases in precipitation at the leading edge of the Luquillo Mountains in Puerto Rico, but consistent declines elsewhere. We conclude with a discussion of potential explanations for these patterns and the attendant risks to water security that subtropical small island nations could face as the climate warms.

50 CFR 665.98 - Management area.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Management area. 665.98 Section 665.98 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... Management area. The American Samoa fishery management area is the EEZ seaward of the Territory of American...

Transformation and fate of microphytobenthos carbon in subtropical shallow subtidal sands: A 13C-labeling study

NARCIS (Netherlands)

Oakes, J.M.; Eyre, B.D.; Middelburg, J.J.

2012-01-01

Microphytobenthos (MPB) in photic sediments are highly productive but the fate of this production remains uncertain. Over 33 d, tracing of 13C from added bicarbonate in subtropical shallow subtidal sand showed rapid transfer of MPB-derived carbon to deeper sediment; below 2 cm (31% within 60 h)

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

Science.gov (United States)

Di Tullio, Juliana Couto; Gandra, Tiago B. R.; Zerbini, Alexandre N.; Secchi, Eduardo R.

2016-01-01

Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m) and slope (1500m) off southeastern and southern Brazil (~23°S to ~34°S). The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the subtropical Southwestern

Use of metabolic profiles in dairy cattle in tropical and subtropical countries on smallholder dairy farms

International Nuclear Information System (INIS)

Whitaker, D.A.; Goodger, W.J.; Garcia, M.; Perera, B.M.A.O.; Wittwer, F.

1999-01-01

Metabolic profile testing has generally been used as part of a multi-disciplinary approach for dairy herds in temperate climates. Our goal was to evaluate the effectiveness of the technique for identifying constraints on productivity in small herds in environments less favourable for milk production. Metabolites tested were chosen for stability in the sample after collection of blood, ease of analysis and practical knowledge of the meaning of the results. Blood levels of five different metabolites in low producing dairy cows belonging to smallholders in tropical and subtropical environments were measured. The study involved 13 projects with 80 cows in each, carried out in six Latin American, six Asian and one southern European country. Data was also collected on feeding, body condition (BCS) and weight change, parasitism and reproduction. In Chile, Mexico, Paraguay, Philippines, Uruguay and Venezuela globulin levels were high in more than 17% of cows sampled on each occasion. Globulin levels were also high in Turkey and Viet Nam on one or more occasions. In Paraguay 49% of cows had high globulin levels at 2-3 months after calving. These results suggest that inflammatory disease was present to a potentially important degree, although this was not always investigated and not always taken into account. In all countries except Mexico and Venezuela high β-hydroxybutyrate (BHB) levels before calving in many cows highlighted the presence of condition loss in late pregnancy, an important potential constraint on productivity and fertility. Fewer cows showed high BHB levels in lactation where change in BCS and weight was more sensitive for measuring negative energy balance. Urea concentrations were only found to be low in small numbers of cows suggesting that dietary protein shortages were not common. Albumin values were low mainly in cows where globulin values were high and so did not generally provide additional information. The exception was in China where pregnant yaks

Analysis of sensitivity to different parameterization schemes for a subtropical cyclone

Science.gov (United States)

Quitián-Hernández, L.; Fernández-González, S.; González-Alemán, J. J.; Valero, F.; Martín, M. L.

2018-05-01

A sensitivity analysis to diverse WRF model physical parameterization schemes is carried out during the lifecycle of a Subtropical cyclone (STC). STCs are low-pressure systems that share tropical and extratropical characteristics, with hybrid thermal structures. In October 2014, a STC made landfall in the Canary Islands, causing widespread damage from strong winds and precipitation there. The system began to develop on October 18 and its effects lasted until October 21. Accurate simulation of this type of cyclone continues to be a major challenge because of its rapid intensification and unique characteristics. In the present study, several numerical simulations were performed using the WRF model to do a sensitivity analysis of its various parameterization schemes for the development and intensification of the STC. The combination of parameterization schemes that best simulated this type of phenomenon was thereby determined. In particular, the parameterization combinations that included the Tiedtke cumulus schemes had the most positive effects on model results. Moreover, concerning STC track validation, optimal results were attained when the STC was fully formed and all convective processes stabilized. Furthermore, to obtain the parameterization schemes that optimally categorize STC structure, a verification using Cyclone Phase Space is assessed. Consequently, the combination of parameterizations including the Tiedtke cumulus schemes were again the best in categorizing the cyclone's subtropical structure. For strength validation, related atmospheric variables such as wind speed and precipitable water were analyzed. Finally, the effects of using a deterministic or probabilistic approach in simulating intense convective phenomena were evaluated.

White-faced storm-petrels Pelagodroma marina predated by gulls as biological monitors of plastic pollution in the pelagic subtropical Northeast Atlantic

International Nuclear Information System (INIS)

Furtado, Ricardo; Menezes, Dilia; Santos, Carolina Jardim; Catry, Paulo

2016-01-01

Marine plastic pollution is rapidly growing and is a source of major concern. Seabirds often ingest plastic debris and are increasingly used as biological monitors of plastic pollution. However, virtually no studies have assessed plastics in seabirds in the deep subtropical North Atlantic. We investigated whether remains of white-faced storm-petrels (WFSP) present in gull pellets could be used for biomonitoring. We analysed 263 pellets and 79.0% of these contained plastic debris originating in the digestive tract of WFSP. Pellets with no bird prey did not contain plastics. Most debris were fragments (83.6%) with fewer plastic pellets (8.2%). Light-coloured plastics predominated (71.0%) and the most frequent polymer was HDPE (73.0%). Stable isotopes in toe-nails of WFSP containing many versus no plastics did not differ, indicating no individual specialisation leading to differential plastic ingestion. We suggest WFSP in pellets are highly suitable to monitor the little known pelagic subtropical Northeast Atlantic. - Highlights: • Plastics in gull pellets reflect contamination of their avian prey. • 79% of white-faced storm petrels in the Northeast Atlantic contain plastics. • Gull pellets are suitable to monitor the little known subtropical NE Atlantic.

History of Asian American psychology.

Science.gov (United States)

Leong, Frederick T L; Okazaki, Sumie

2009-10-01

An overview of the history of Asian American psychology is provided by reviewing the context for the development of the field as well as the early founding of the Asian American Psychological Association (AAPA). The presidents of AAPA as well as key events and conferences are noted. The involvement of AAPA leaders in national mental health policies and activities are reviewed. The substantive areas of Asian American psychology and the education and training of Asian American psychologists are also discussed. The article ends with some comments about the future of Asian American psychology. Copyright 2009 APA, all rights reserved.

Hepatitis B and liver cancer knowledge and preventive practices among Asian Americans in the San Francisco Bay Area, California.

Science.gov (United States)

Wu, Charlotte A; Lin, Steven Y; So, Samuel K; Chang, Ellen T

2007-01-01

Chronic hepatitis B virus (HBV) infection causes liver cancer and disproportionately affects the Asian community in the U.S. In order to advance HBV and liver cancer awareness and prevention, it is important to identify existing gaps in knowledge and preventive practices among Asian Americans. Therefore, the authors administered a written questionnaire to 199 adults in the Asian-American community of the San Francisco Bay Area, California. Although the majority of adults had at least a college education, knowledge regarding HBV transmission, prevention, symptoms, risks, and occurrence was low. Fewer than 60% reported having been tested for HBV, only 31% reported having been vaccinated against HBV, and only 44% reported having had their children vaccinated. Asians, especially those born in China or Southeast Asia, had significantly poorer knowledge regarding HBV and liver cancer than non-Asians. Those with higher knowledge levels were significantly more likely to have been tested for HBV and to have had their children vaccinated. Younger adults, women, Caucasians, more highly educated individuals, those not born in China or Hong Kong, and those with a personal or family history of liver disease were more likely to have taken preventive action against HBV. Our results suggest that HBV and liver cancer knowledge among Asian Americans, especially Chinese Americans, is poor, and that better knowledge is associated with increased preventive practices. Thus, there is a need for increased HBV education and improved community-based interventions to prevent HBV-related liver disease in the high-risk Asian-American community.

Geomorphology, disturbance, and the soil and vegetation of two subtropical wet steepland watersheds of Puerto Rico.

Science.gov (United States)

Ariel E. Lugo F.N. Scatena

1995-01-01

Relationships between landforms, soil nutrients, forest structure, and the relative importance of different disturbances were quantified in two subtropical wet steepland watersheds in Puerto Rico. Ridges had fewer landslides and treefall gaps, more above-ground biomass, older aged stands, and greater species richness than other landscape positions. Ridge soils had...

Water quality dynamics in an urbanizing subtropical estuary(Oso Bay, Texas).

Science.gov (United States)

Wetz, Michael S; Hayes, Kenneth C; Fisher, Kelsey V B; Price, Lynn; Sterba-Boatwright, Blair

2016-03-15

Results are presented from a study of water quality dynamics in a shallow subtropical estuary, Oso Bay, Texas, which has a watershed that has undergone extensive urbanization in recent decades. High inorganic nutrient, dissolved organic matter and chlorophyll concentrations, as well as low pH (Oso Bay that receives wastewater effluent. Despite being shallow (Oso Bay, suggesting that it may be exported to adjacent Corpus Christi Bay and contribute to seasonal hypoxia development in that system as well. These results argue for wastewater nutrient input reductions in order to alleviate the symptoms of eutrophication. Copyright © 2016 Elsevier Ltd. All rights reserved.

Perceived value in food selection when dining out: comparison of African Americans and Euro-Americans.

Science.gov (United States)

Vinci, Debra M; Philipp, Steven F

2007-06-01

This descriptive study compares African Americans' and Euro-Americans' perceived value of food selection pertaining to cost, portion size, and meal satisfaction when eating away from home. A stratified sample was drawn from a southern U.S. metropolitan area (N= 1,011; 486 African American, 525 Euro-American). Analysis showed no difference between African-American and Euro-American adults by sex or how often they dined out. These two groups significantly differed across years of education, age, and answering 14 of 18 rated statements on value perceptions. African-Americans' value perceptions were influenced more by lower cost foods and larger portion sizes than those of Euro-Americans. For meal satisfaction, African Americans were more likely to agree with statements that indicate preferring foods high in energy and low in essential micronutrient density. This study supports the need for more investigation.

Changes in carbon pool and stand structure of a native subtropical mangrove forest after inter-planting with exotic species Sonneratia apetala.

Science.gov (United States)

Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

2014-01-01

In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration.

Biodiversity of frog haemoparasites from sub-tropical northern KwaZulu-Natal, South Africa

OpenAIRE

Edward C. Netherlands; Courtney A. Cook; Donnavan J.D. Kruger; Louis H. du Preez; Nico J. Smit

2015-01-01

Since South Africa boasts a high biodiversity of frog species, a multispecies haemoparasite survey was conducted by screening the blood from 29 species and 436 individual frogs. Frogs were collected at three localities in sub-tropical KwaZulu-Natal, a hotspot for frog diversity. Twenty per cent of the frogs were infected with at least one of five groups of parasites recorded. Intraerythrocytic parasites comprising Hepatozoon, Dactylosoma, and viral or bacterial organisms, as well as extracell...

Breeding biology of passerines in a subtropical montane forest in northwestern Argentina

Science.gov (United States)

Auer, S.K.; Bassar, R.D.; Fontaine, J.J.; Martin, T.E.

2007-01-01

The breeding ecology of south temperate bird species is less widely known than that of north temperate species, yet because they comprise a large portion of the world's avian diversity, knowledge of their breeding ecology can contribute to a more comprehensive understanding of the geographic diversity of avian reproductive traits and life history strategies. We provide the first detailed examination of the reproductive strategies of 18 forest passerines of subtropical, northwestern Argentina. Mean clutch sizes were smaller and egg mass was greater than for north temperate birds, but differed among species and nest types, with cavity-nesters having larger clutches than species with open-cup and enclosed nests. Across all species, the average breeding season duration was 50 days; thus, the common perception that southern species have smaller clutch sizes because of longer breeding seasons is not supported in this community. Daily nest predation rates were influenced by nest type, cavity nests suffering the least from predation, as found in north temperate systems. Only females incubated eggs in all but one species, whereas both parents fed and cared for nestlings in all species. Mean nest attentiveness was low compared to north temperate passerines. Mean hourly nestling feeding rates differed among species and were negatively related to nest predation risk. In short, coexisting species in this subtropical forest varied in their life history strategies, in part correlated with variation in nest predation risk, but also differing from north temperate species. ?? The Cooper Ornithological Society 2007.

Soil and phosphorus accretion rates in sub-tropical wetlands: Everglades Stormwater Treatment Areas as a case example.

Science.gov (United States)

Bhomia, R K; Inglett, P W; Reddy, K R

2015-11-15

Wetlands are known to serve as sinks for particulate matter and associated nutrients and contaminants. Consequently rate of soil accretion is critical for continued performance of wetlands to provide ecosystem services including water quality improvement and reduce excess contaminant loads into downstream waters. Here we demonstrate a new technique to determine rate of soil accretion in selected subtropical treatment wetlands located in southern USA. We also report changes in soil accretion rates and subsequent phosphorus (P) removal efficiency with increasing operational history of these treatment wetlands. Utilizing discernible signatures preserved within the soil depth profiles, 'change points' (CP) that corresponded to specific events in the life history of a wetland were determined. The CP was observed as an abrupt transition in the physico-chemical properties of soil as a manifestation of prevailing historical conditions (e.g. startup of treatment wetlands in this case). Vertical depth of CP from the soil surface was equivalent to the depth of recently accreted soil (RAS) and used for soil accretion rate calculations. Annual soil and P accretion rates determined using CP technique (CPT) in studied wetlands ranged from 1.0±0.3 to 1.7±0.8 cm yr(-1) and 1.3±0.6 to 3.3±2 g m(-2) yr(-1), respectively. There was no difference in RAS depth between emergent and submerged aquatic vegetation communities found at the study location. Our results showed that soil and P accretion rates leveled off after 10 yr of treatment wetlands' operation. On comparison, soil accretion rates and RAS depth determined by CPT were commensurate with that measured by other techniques. CPT can be easily used where a reliable record of wetland establishment date or some significant alteration/perturbation is available. This technique offers a relatively simple alternative to determine vertical accretion rates in free-water surface wetlands. Copyright © 2015 Elsevier B.V. All rights

Morphological and physio-chemical characterization of five Canistel accessions at the subtropical horticulture research station in Miami Florida

Science.gov (United States)

Fruit of five canistel cultivars, 'Fairchild','E11', 'Keisau', 'TREC#3' and 'TREC 3680' were evaluated and characterized at the National Germplasm Repository, Subtropical horticulture Research Station (SHRS) Miami, Florida. Thirty fruits were harvested from clonal accessions during July and August, ...

Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya

Directory of Open Access Journals (Sweden)

Kumar Munesh

2009-08-01

Full Text Available Abstract Background The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC. However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known. Results This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora and subtropical (Pinus roxburghii forests, respectively. Conclusion The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation

Characterization and evaluation of five jaboticaba accessions at the subtropical horticulture research station in Miami, Florida

Science.gov (United States)

Fruit of five Jaboticaba (Myrciaria caulifloria) cultivars ‘MC-05-06’, ‘MC-05-14’, ‘MC-05-12’, ‘MC-06-15,’ and ‘MC-06-14’ were evaluated and characterized at the National Germplasm Repository, Subtropical horticulture Research Station (SHRS) Miami, Florida. Thirty fruits were harvested from clona...

Assessment of the Status of African-Americans. Volume III: The Education of African-Americans.

Science.gov (United States)

Willie, Charles V., Ed.; Garibaldi, Antoine M., Ed.; Reed, Wornie L., Ed.

In 1987 a project was undertaken to assess the status of African Americans in the United States in the topical areas to be addressed by the National Research Council's Study Committee on the Status of Black Americans: education, employment, income and occupations, political participation and the administration of justice, social and cultural…

Effect of Simulated N Deposition on Soil Exchangeable Cations in Three Forest Types of Subtropical China

Institute of Scientific and Technical Information of China (English)

LU Xian-Kai; MO Jiang-Ming; P.GUNDERSERN; ZHU Wei-Xing; ZHOU Guo-Yi; LI De-Jun; ZHANG Xu

2009-01-01

The effects of simulated nitrogen (N) deposition on soil exchangeable cations were studied in three forest types of subtropical China.Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control (0 kg N ha-1 year-1),low N (50 kg N ha-1 year-1),medium N (100 kg N ha-1 year-1) and high N (150 kg N ha-1 ycar-1),and only three treatments (i.e.,control,low N,medium N) were established for the pine and mixed forests.Nitrogen had been applied continuously for 26 months before the measurement.The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests,and exhibited some significant negative symptoms,e.g.,soil acidification,Al mobilization and leaching of base cations from soil.The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations.Response of soil exchangeable cations to N deposition varied in the forests of subtropical China,depending on soil N status and land-nse history.

The impact of a high magnitude flood on metal pollution in a shallow subtropical estuarine embayment.

Science.gov (United States)

Coates-Marnane, J; Olley, J; Burton, J; Grinham, A

2016-11-01

Drought-breaking floods pose a risk to coastal water quality as sediments, nutrients, and pollutants stored within catchments during periods of low flow are mobilized and delivered to coastal waters within a short period of time. Here we use subtidal surface sediment surveys and sediment cores to explore the effects of the 2011 Brisbane River flood on trace metals zinc (Zn), lead (Pb), copper (Cu), nickel (Ni), chromium (Cr), manganese (Mn), and phosphorus (P) deposition in Moreton Bay, a shallow subtropical bay in eastern Australia. Concentrations of Zn, Cu, and Pb in sediments in central Moreton Bay derived from the 2011 flood were the highest yet observed in the Bay. We suggest flushing of metal rich sediments which had accumulated on the Brisbane River floodplain and in its estuary during the preceding 10 to 40years of low flows to be the primary source of this increase. This highlights the importance of intermittent high magnitude floods in tidally influenced rivers in controlling metal transport to coastal waters in subtropical regions. Copyright © 2016. Published by Elsevier B.V.

Los Dos Mundos: Rural Mexican Americans, Another America.

Science.gov (United States)

Baker, Richard

This book explores race relations between Mexican Americans and Anglo Americans in "Middlewest," a fictitious name for an actual rural Idaho community with the highest proportion of Mexican Americans in the state. Many Mexican Americans in this predominantly agricultural area are current or former migrant workers. The first chapter…

Sago-Type Palms Were an Important Plant Food Prior to Rice in Southern Subtropical China

Science.gov (United States)

Yang, Xiaoyan; Barton, Huw J.; Wan, Zhiwei; Li, Quan; Ma, Zhikun; Li, Mingqi; Zhang, Dan; Wei, Jun

2013-01-01

Poor preservation of plant macroremains in the acid soils of southern subtropical China has hampered understanding of prehistoric diets in the region and of the spread of domesticated rice southwards from the Yangtze River region. According to records in ancient books and archaeological discoveries from historical sites, it is presumed that roots and tubers were the staple plant foods in this region before rice agriculture was widely practiced. But no direct evidences provided to test the hypothesis. Here we present evidence from starch and phytolith analyses of samples obtained during systematic excavations at the site of Xincun on the southern coast of China, demonstrating that during 3,350–2,470 aBC humans exploited sago palms, bananas, freshwater roots and tubers, fern roots, acorns, Job's-tears as well as wild rice. A dominance of starches and phytoliths from palms suggest that the sago-type palms were an important plant food prior to the rice in south subtropical China. We also believe that because of their reliance on a wide range of starch-rich plant foods, the transition towards labour intensive rice agriculture was a slow process. PMID:23667584

Thermal performance of natural airflow window in subtropical and temperate climate zones - A comparative study

International Nuclear Information System (INIS)

Chow Tintai; Lin Zhang; Fong Kwongfai; Chan Lokshun; He Miaomiao

2009-01-01

Airflow window is highly useful in conserving building energy, and lessens the comfort problems caused by glazing. In this study, the thermal performance of a natural airflow window was examined through the use of a dynamic model, developed based on the integrated energy balance and airflow networks. The validity of the model was first tested by measured data obtained from a prototype installed at an environmental chamber. The application in the subtropical and temperate climate zones were then examined with the typical weather data of Hong Kong and Beijing. The findings confirmed that the natural airflow window can achieve substantial energy saving in both cities, and the reversible window frame is only required for Beijing, a location with hot summer and cold winter. The space cooling load via fenestration in Hong Kong, a subtropical city, can be reduced to 60% of the commonly used single absorptive glazing. In Beijing, as an example of the temperate climate, this can be reduced to 75% of the commonly used double glazing configuration in the summer period, and the space heat gain can be improved by 46% in the winter period.

High 210Po atmospheric deposition flux in the subtropical coastal area of Japan

International Nuclear Information System (INIS)

Tateda, Yutaka; Iwao, Kenji

2008-01-01

Bulk atmospheric deposition fluxes of 210 Po and 210 Pb were measured at three coastal regions of Japan, the Pacific Ocean coastal area of the Japanese mainland (Odawa Bay), the Chinese continental side of Japanese coastal area (Tsuyazaki), and an isolated island near Okinawa (Akajima). Wet and dry fallout collectors were continuously deployed from September 1997 through August 1998 for periods of 3 to 31 days depending on the frequency of precipitation events. Annual 210 Pb deposition fluxes at Odawa Bay (35 o N 139 o E), Tsuyazaki (33 o N 130 o E) and Akajima (26 o N 127 o E) were 73.3 ± 8.0, 197 ± 35 and 78.5 ± 8.0 Bq m -2 y -1 , respectively. Higher 210 Pb deposition was observed at the Chinese continental side of Japanese coast than at the Pacific Ocean coastal site. The high 210 Pb atmospheric flux at the Chinese continental side coast was thought to be attributable to 222 Rn-rich air-mass transport from the Chinese continent during the winter monsoon. In contrast, the annual 210 Po deposition fluxes at the three study sites were 13.0 ± 2.3 (Odawa Bay), 21.9 ± 4.4 (Tsuyazaki) and 58.4 ± 7.7 (Akajima) Bq m -2 y -1 , respectively, indicating unusual high 210 Po deposition at Akajima during winter. Anomalous unsupported 210 Po input was observed during summer 1997, suggesting unknown source of 210 Po at this area

Effects of natural banks of free-floating plants on zooplankton community in a shallow subtropical lake in Southern Brazil

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Vanessa Gazulha

2011-08-01

Full Text Available The aim of this study was to test the effects of natural free-floating plants on zooplankton distribution in a shallow subtropical lake. First, the hypothesis that free-floating plants have an effect on physico-chemicals, leading to a decrease on nutrient availability and influencing the phytoplankton biomass and zooplankton community was tested. Second, the hypothesis that free-floating plants act as a refuge for zooplankton was tested. Three microhabitats were selected: free-floating plants, littoral area and open water. Results demonstrated that the effects of different microhabitats on phytoplankton biomass and physico-chemicals were not significant, indicating a weak influence of the plants. Zooplankton densities were higher in free-floating plants and littoral area, although the effect of microhabitats was weak for most of the predominant genera. The absence of free-floating plant effects on phytoplankton and physico-chemicals showed that it was not a factor influencing the microcrustacean distribution in the microhabitats. Low differences in densities of zooplankton among microhabitats and low abundance of large-bodied cladocerans led to reject the hypothesis that free-floating plants act as a refuge for zooplankton.

American Academy of Dental Sleep Medicine

Science.gov (United States)

... New Research AADSM Highlights Members More news... Dental Sleep Medicine: An area of dental practice that focuses on ... SomnoMed Silver Sponsors Copyright © American Academy of Dental Sleep Medicine, All Rights Reserved. American Academy of Dental Sleep ...

FUEL CONDITIONS ASSOCIATED WITH NATIVE AND EXOTIC GRASSES IN A SUBTROPICAL DRY FOREST IN PUERTO RICO

Science.gov (United States)

Jarrod M. Thaxton; Skip J. Van Bloem; Stefanie Whitmire

2012-01-01

Exotic grasses capable of increasing frequency and intensity of anthropogenic fire have invaded subtropical and tropical dry forests worldwide. Since many dry forest trees are susceptible to fire, this can result in decline of native species and loss of forest cover. While the contribution of exotic grasses to altered fire regimes has been well documented, the role of...

An A-train and MERRA view of cloud, thermodynamic, and dynamic variability within the subtropical marine boundary layer

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B. H. Kahn

2017-08-01

Full Text Available The global-scale patterns and covariances of subtropical marine boundary layer (MBL cloud fraction and spatial variability with atmospheric thermodynamic and dynamic fields remain poorly understood. We describe an approach that leverages coincident NASA A-train and the Modern Era Retrospective-Analysis for Research and Applications (MERRA data to quantify the relationships in the subtropical MBL derived at the native pixel and grid resolution. A new method for observing four subtropical oceanic regions that capture transitions from stratocumulus to trade cumulus is demonstrated, where stratocumulus and cumulus regimes are determined from infrared-based thermodynamic phase. Visible radiances are normally distributed within stratocumulus and are increasingly skewed away from the coast, where trade cumulus dominates. Increases in MBL depth, wind speed, and effective radius (re, and reductions in 700–1000 hPa moist static energy differences and 700 and 850 hPa vertical velocity correspond with increases in visible radiance skewness. We posit that a more robust representation of the cloudy MBL is obtained using visible radiance rather than retrievals of optical thickness that are limited to a smaller subset of cumulus. The method using the combined A-train and MERRA data set has demonstrated that an increase in re within shallow cumulus is strongly related to higher MBL wind speeds that further correspond to increased precipitation occurrence according to CloudSat, previously demonstrated with surface observations. Hence, the combined data sets have the potential of adding global context to process-level understanding of the MBL.

Leishmaniose tegumentar americana: flebotomíneos de área de transmissão no Norte do Paraná, Brasil American cutaneous leishmaniasis: phlebotominae of the area of transmission in the North of Parana, Brazil

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Ueslei Teodoro

1991-04-01

Full Text Available Dos casos de leishmaniose tegumentar diagnosticados no Laboratório de Ensino e Pesquisa de Análises Clínicas da Universidade Estadual de Maringá-PR (Brasil, a maioria está relacionada a áreas, no Norte do Paraná, que vem sendo ocupadas desde a década de 1940, quando se iniciou extenso desmatamento naquela Região. A vegetação nativa, já em grande parte destruída, é constituída por mata densa do tipo tropical de transição para subtropical. A paisagem no seu conjunto é de planalto, com clima tropical de transição para subtropical, temperaturas médias anuais entre 20°C e 22°C e média do mês mais quente superior a 22°C. Das florestas nativas restam poucas e esparsas manchas de vegetação, geralmente modificadas, ao longo das bacias dos rios Ivaí, Paranapanema e Paraná, e seus afluentes. Neste ambiente foram feitas 24 capturas de flebotomíneos, 2 por mês, de outubro de 1986 a setembro de 1987, das 18 horas à l hora do dia seguinte. As capturas, com armadilhas de Shannon, foram realizadas às margens de mata modificada, tendo sido classificados 16.496 flebotomíneos, pertencentes na sua quase totalidade a 13 espécies. Observou-se prevalência de Lutzomyia whitmani com 11.188 (67,82% exemplares, seguido por Lutzomyia intermedia com 2.900 (17,58% e Lutzomyia migonei com 1.491 (9,03%. Lutzomyia whitmani e Lutzomyia intermedia vêm mostrando grande capacidade de adaptação nos ambientes antrópicos, onde têm destacado papel na transmissão de leishmaniose.Most of the cases of cutaneous leishmaniasis diagnosed in the laboratory of the State University of Maringá, Paraná, Brazil, are related to areas of northern Paraná State, which have been settled since 40 years age, when the destructions of vast areas of forest in this region was begun. The native vegetation, already, in large part, destroyed is constituted of dense forest of the type found in the transition from tropical to subtropical regions. The landscape is

The plant economics spectrum is structured by leaf habits and growth forms across subtropical species.

Science.gov (United States)

Zhao, Yan-Tao; Ali, Arshad; Yan, En-Rong

2017-02-01

The plant economics spectrum that integrates the combination of leaf and wood syndromes provides a useful framework for the examination of species strategies at the whole-plant level. However, it remains unclear how species that differ in leaf habits and growth forms are integrated within the plant economics spectrum in subtropical forests. We measured five leaf and six wood traits across 58 subtropical plant species, which represented two leaf habits (evergreen vs deciduous) and two growth forms (tree vs shrub) in eastern China. Principal component analysis (PCA) was employed separately to construct the leaf (LES), wood (WES) and whole-plant (WPES) economics spectra. Leaf and wood traits are highly intra- and intercorrelated, thus defining not only the LES and WES, but also a WPES. Multi-trait variations in PCAs revealed that the traits which were representative of the acquisitive strategy, i.e., cheap tissue investment and rapid returns on that investment, were clustered at one end, while traits that represented the conservative strategy, i.e., expensive tissue investment and slower returns, were clustered at other end in each of the axes of the leaf and wood syndromes (PC1-axis) and the plant height strategy (PC2-axis). The local WPES, LES and WES were tightly correlated with each other. Evergreens shaped the conservative side, while deciduous species structured the acquisitive side of the WPES and LES. With respect to plant height strategies, trees formulated the acquisitive side and shrub species made up the conservative side of the WPES, LES and WES. In conclusion, our results suggested that the LES and WES were coordinated to a WPES for subtropical species. The finding of this local spectrum of plant form and function would be beneficial for modeling nutrient fluxes and species compositions in the changing climate, but also for understanding species strategies in an evolutionary context. © The Author 2016. Published by Oxford University Press. All rights

Birds surveyed in the harvested and unharvested areas of a reduced-impact logged forestry concession, located in the lowland subtropical humid forests of the Department of Santa Cruz, Bolivia.

Directory of Open Access Journals (Sweden)

Felton, A.

2007-01-01

Full Text Available As part of a larger study of reduced-impactlogging effects on bird community composition,we surveyed birds from December to Februaryduring the 2003-2004 wet-season within harvestedand unharvested blocks of the La Chonta forestryconcession, Department of Santa Cruz, Bolivia.The logged forest was harvested using reduced-impactlogging techniques between one and fouryears previously. During point count surveys, weidentified 5062 individual birds, belonging to 155species, and 33 families. We provide a list of birdspecies found within the harvested andunharvested blocks of the concession for thebenefit of other researchers assessing theresponses of Neotropical avifauna to disturbance,and to facilitate increased understanding of thediverse bird assemblages found within thelowland subtropical humid forests of Bolivia.

Epidemiological aspects of American Cutaneous Leishmaniasis in a periurban area of the metropolitan region of Belo Horizonte, Minas Gerais, Brazil

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V. M. A. Passos

1993-03-01

Full Text Available In order to characterize the epidemiology of American Cutaneous Leishmaniasis (ACL in a periurban area of the municipality of Sabará in the metropolitan region of Belo Horizonte (MRBH, an area until then considered free of the disease, a cross sectional survey was undertaken in 1990. The survey of the population consisted of 1119 interviews and 881 clinical examinations using Montenegro's skin test (MST. A low prevalence (3.7% of positive MST was encountered. The disease had been occuring in the area for about 20 years in the form of sporadic cases. The predominant species of sandfly both in domestic areas and nearby areas of secondary vegetation was Lutzomyia whitmani. A canine survey of delayed hypersensitivity to the antigen P10,000 identified only one dog with a positive reaction out of 113 examined. The transmission of ACL in MRBH was confirmed. The occurrence of the disease in women, children and individuals with no contact with forest areas as well as the presence of potential vector species in the domiciliar environment, suggests the transmission of the disease in this environment.

DINÂMICA DA CHUVA DE SEMENTES EM REMANESCENTE DE FLORESTA ESTACIONAL SUBTROPICAL

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Marta Silvana Volpato Sccoti

2016-01-01

Full Text Available The aim of this study was to evaluate the dynamics of the seed rain in two Floristic groups formed in a remnant of Subtropical Seasonal Forest. The clusters were characterized by successional stage of the forest, namely group I (Secondary Forest in Intermediate Stage-FSEM, with a predominance of early secondary species, and group II (Secondary Forest in Advanced Stage-FSEA, with a predominance of late secondary species. Seed rain was evaluated in 70 collectors of 1 m², randomly distributed in the two groups, whereas in group I were installed 15 collectors and in group II, due to its greater area, 55 collectors. The deposited material was collected monthly from October 2008 to October 2010. The dynamics of seed rain was assessed by the density of seeds of each species of dispersal and seasonal production. We used the nonparametric Test of Wilcoxon Sum of Orders (W to determine statistical differences in the mean density of seeds in each year of assessment for each patch of forest. Seed rain in the remaining studied during three years of study, was represented by 114 species and higher seed production occurred in 2008 (1632-seeds.m-2 in group I and 1270-seeds.m-2 in group II, mainly due to the occurrence of high production Chusquea ramosissima Lindm., Dasyphyllum spinescens (Less. Cabrera, Vernonanthura discolor (Spreng. H.Rob. Only in the second year (2009 observed statistical differences in mean density between the two groups (FSEM=565.6 seeds.m-2 and FSEA=274 seeds.m-2; Z=1.96 and tabulated; W FSEM x FSEA =2.248. Zoochorous species predominated in the study area, and periods of increased seed production were the winter and spring. The seed rain proved important mechanism for natural regeneration of remnant forest and is affected by climate conditions and successional stage of the forest.

Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China

International Nuclear Information System (INIS)

Zhou, Jun; Wang, Zhangwei; Zhang, Xiaoshan; Chen, Jian

2015-01-01

Tieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m −2 and averaged 14.5 mg m −2 , indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils. - Highlights: • Soil THg pools and influence factors were studied at an acidic catchment in southwestern China. • THg concentrations was increased significantly with TOM concentrations and altitude increasing, decreased with pH. • THg pools in soils were highly elevated and deepened on TOM pools and altitude. • Difference in THg output by volatilization and runoff was a major reason for THg distribution at different altitudes. - Mercury pools increased with altitude increasing as mercury lost more at low elevation area in acidic subtropical forest

Influence of Ecological Factors on Estimation of Impervious Surface Area Using Landsat 8 Imagery

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Yuqiu Jia

2017-07-01

Full Text Available Estimation of impervious surface area is important to the study of urban environments and social development, but surface characteristics, as well as the temporal, spectral, and spatial resolutions of remote sensing images, influence the estimation accuracy. To investigate the effects of regional environmental characteristics on the estimation of impervious surface area, we divided China into seven sub-regions based on climate, soil type, feature complexity, and vegetation phenology: arid and semi-arid areas, Huang-Huai-Hai winter wheat production areas, typical temperate regions, the Pearl River Delta, the middle and lower reaches of the Yangtze River, typical tropical and subtropical regions, and the Qinghai Tibet Plateau. Impervious surface area was estimated from Landsat 8 images of five typical cities, including Yinchuan, Shijiazhuang, Shenyang, Ningbo, and Kunming. Using the linear spectral unmixing method, impervious and permeable surface areas were determined at the pixel-scale based on end-member proportions. We calculated the producer’s accuracy, user’s accuracy, and overall accuracy to assess the estimation accuracy, and compared the accuracies among images acquired from different seasons and locations. In tropical and subtropical regions, vegetation canopies can confound the identification of impervious surfaces and, thus, images acquired in winter, early spring, and autumn are most suitable; estimations in the Pearl River Delta, the middle and lower reaches of the Yangtze River are influenced by soil, vegetation phenology, vegetation canopy, and water, and images acquired in spring, summer, and autumn provide the best results; in typical temperate areas, images acquired from spring to autumn are most effective for estimations; in winter wheat-growing areas, images acquired throughout the year are suitable; and in arid and semi-arid areas, summer and early autumn, during which vegetation is abundant, are the optimal seasons for

Temperature dependence of plankton community metabolism in the subtropical and tropical oceans

KAUST Repository

Garcia-Corral, Lara S.; Holding, Johnna M.; Carrillo-de-Albornoz, Paloma; Steckbauer, Alexandra; Pé rez-Lorenzo, Marí a; Navarro, Nuria; Serret, Pablo; Gasol, Josep M.; Moran, Xose Anxelu G.; Estrada, Marta; Fraile-Nuez, Eugenio; Bení tez-Barrios, Veró nica; Agusti, Susana; Duarte, Carlos M.

2017-01-01

Here we assess the temperature dependence of the metabolic rates (gross primary production (GPP), community respiration (CR), and the ratio GPP/CR) of oceanic plankton communities. We compile data from 133 stations of the Malaspina 2010 Expedition, distributed among the subtropical and tropical Atlantic, Pacific, and Indian oceans. We used the in vitro technique to measured metabolic rates during 24 h incubations at three different sampled depths: surface, 20%, and 1% of the photosynthetically active radiation measured at surface. We also measured the % of ultraviolet B radiation (UVB) penetrating at surface waters. GPP and CR rates increased with warming, albeit different responses were observed for each sampled depth. The overall GPP/CR ratio declined with warming. Higher activation energies (E-a) were derived for both processes (GPP(Chla) = 0.97; CRChla = 1.26; CRHPA = 0.95 eV) compared to those previously reported. The Indian Ocean showed the highest E-a (GPP(Chla) = 1.70; CRChla = 1.48; CRHPA = 0.57 eV), while the Atlantic Ocean showed the lowest (GPP(Chla) = 0.86; CRChla = 0.77; CRHPA = -0.13 eV). We believe that the difference between previous assessments and the ones presented here can be explained by the overrepresentation of Atlantic communities in the previous data sets. We found that UVB radiation also affects the temperature dependence of surface GPP, which decreased rather than increased under high levels of UVB. Ocean warming, which causes stratification and oligotrophication of the subtropical and tropical oceans, may lead to reduced surface GPP as a result of increased penetration of UVB radiation.

Temperature dependence of plankton community metabolism in the subtropical and tropical oceans

KAUST Repository

Garcia-Corral, Lara S.

2017-06-22

Here we assess the temperature dependence of the metabolic rates (gross primary production (GPP), community respiration (CR), and the ratio GPP/CR) of oceanic plankton communities. We compile data from 133 stations of the Malaspina 2010 Expedition, distributed among the subtropical and tropical Atlantic, Pacific, and Indian oceans. We used the in vitro technique to measured metabolic rates during 24 h incubations at three different sampled depths: surface, 20%, and 1% of the photosynthetically active radiation measured at surface. We also measured the % of ultraviolet B radiation (UVB) penetrating at surface waters. GPP and CR rates increased with warming, albeit different responses were observed for each sampled depth. The overall GPP/CR ratio declined with warming. Higher activation energies (E-a) were derived for both processes (GPP(Chla) = 0.97; CRChla = 1.26; CRHPA = 0.95 eV) compared to those previously reported. The Indian Ocean showed the highest E-a (GPP(Chla) = 1.70; CRChla = 1.48; CRHPA = 0.57 eV), while the Atlantic Ocean showed the lowest (GPP(Chla) = 0.86; CRChla = 0.77; CRHPA = -0.13 eV). We believe that the difference between previous assessments and the ones presented here can be explained by the overrepresentation of Atlantic communities in the previous data sets. We found that UVB radiation also affects the temperature dependence of surface GPP, which decreased rather than increased under high levels of UVB. Ocean warming, which causes stratification and oligotrophication of the subtropical and tropical oceans, may lead to reduced surface GPP as a result of increased penetration of UVB radiation.

Measuring surface salinity in the N. Atlantic subtropical gyre. The SPURS-MIDAS cruise, spring 2013

Science.gov (United States)

Font, Jordi; Ward, Brian; Emelianov, Mikhail; Morisset, Simon; Salvador, Joaquin; Busecke, Julius

2014-05-01

SPURS-MIDAS (March-April 2013) on board the Spanish R/V Sarmiento de Gamboa was a contribution to SPURS (Salinity Processes in the Upper ocean Regional Study) focused on the processes responsible for the formation and maintenance of the salinity maximum associated to the North Atlantic subtropical gyre. Scientists from Spain, Ireland, France and US sampled the mesoscale and submesoscale structures in the surface layer (fixed points and towed undulating CTD, underway near surface TSG) and deployed operational and experimental drifters and vertical profilers, plus additional ocean and atmospheric data collection. Validation of salinity maps obtained from the SMOS satellite was one of the objectives of the cruise. The cruise included a joint workplan and coordinated sampling with the US R/V Endeavor, with contribution from SPURS teams on land in real time data and analysis exchange. We present here an overview of the different kinds of measurements made during the cruise, as well as a first comparison between SMOS-derived sea surface salinity products and salinity maps obtained from near-surface sampling in the SPURS-MIDAS area and from surface drifters released during the cruise.

Integrated Studies of a Regional Ozone Pollution Synthetically Affected by Subtropical High and Typhoon System in the Yangtze River Delta Region, China

Science.gov (United States)

Xie, M.; Shu, L.

2017-12-01

Severe high ozone (O3) episodes usually have close relations to synoptic systems. A regional continuous O3 pollution episode was detected over the Yangtze River Delta (YRD) region in China during August 7-12, 2013, in which the O3 concentrations in more than half of the cities exceeded the national air quality standard. By means of the observational analysis and the WRF/CMAQ numerical simulation, the characteristics and the essential impact factors of the typical regional O3 pollution are investigated. The observational analysis shows that the atmospheric subsidence dominated by Western Pacific subtropical high plays a crucial role in the formation of high-level O3. In addition, when the YRD cities at the front of Typhoon Utor, the periphery circulation of typhoon system can enhance the downward airflows and cause more serious air pollution. But when the typhoon system weakens the subtropical high, the prevailing southeasterly surface wind leads to the mitigation of the O3 pollution. The Integrated Process Rate (IPR) analysis incorporated in CMAQ is applied to further illustrate the combined influence of subtropical high and typhoon system in this O3 episode. The results show that the vertical diffusion (VDIF) and the gas-phase chemistry (CHEM) are two major contributors to O3 formation. On August 10-11, the cities close to the sea are apparently affected by the typhoon system, with the contribution of VDIF increasing to 28.45 ppb/h in Shanghai and 19.76 ppb/h in Hangzhou. When the YRD region is under the control of the typhoon system, the contribution values of all individual processes decrease to a low level in all cities. These results provide an insight for the O3 pollution synthetically impacted by the Western Pacific subtropical high and the tropical cyclone system.

The South Florida Avocado Breeding Program at USDA-Agricultural Research Service Subtropical Horticulture Research Station (USDA-ARS SHRS)

Science.gov (United States)

USDA-ARS SHRS is part of the USDA National Germplasm Repository system and houses collections of tropical and subtropical fruit trees such as mango, lychee, and avocado. In addition to maintaining the germplasm collections, our mission is to also identify genetic diversity in the collections, to ev...

[Early responses of soil fauna in three typical forests of south subtropical China to simulated N deposition addition].

Science.gov (United States)

Xu, Guolian; Mo, Jiangming; Zhou, Guoyi

2005-07-01

In this paper, simulated N deposition addition (0, 50, 100 and 150 kg x hm(-2) x yr(-1)) by spreading water or NH4NO3 was conducted to study the early responses of soil fauna in three typical native forests (monsoon evergreen broadleaf forest, pine forest, and broadleaf-pine mixed forest) of subtropical China. The results showed that in monsoon evergreen broadleaf forest, N deposition addition had an obviously negative effect on the three indexes for soil fauna, but in pine forest, the positive effect was significant (P soil fauna community could reach the level in mixed forest, even that in monsoon evergreen broadleaf forest at sometime. The responses in mixed forest were not obvious. In monsoon evergreen broadleaf forest, the negative effects were significant (P soil fauna groups. The results obtained might imply the N saturation-response mechanisms of forest ecosystems in subtropical China, and the conclusions from this study were also consisted with some related researches.

The winter diet of elephant in Eastern Cape Subtropical Thicket, Addo Elephant National Park

OpenAIRE

R.G.T. Paley; G.I.H. Kerley

1998-01-01

Direct observational methods were used to establish the winter diet of elephants in Eastern Cape Subtropical Thicket in the Addo Elephant National Park, thereby determining which plant species were most at risk from elephant herbivory. A total of 70 species were identified as food plants for elephants, with the grass Cynodon dactylon and the succulents Portulacaria afra and Platythyra haeckeliana dominating, both in terms of frequency of feeding events and volume consumed. In view of the fact...

Involvement of adrenal hormones in tissue respiration of sub-tropical hibernating and non-hibernating species of frogs.

Science.gov (United States)

Gupta, B B; Mahanta, A

1997-03-01

Effects of norepinephrine (NE), epinephrine (EP), corticosterone and cortisol were studied both in vivo and in vitro on the rate of oxygen consumption of tissues (liver, skeletal muscle and kidney) of sub-tropical Indian frogs Rana limnocharis (a hibernating species) and Rana cyanophlyctis (a non-hibernating species) exposed to natural climatic conditions during winter and summer/rainy seasons. Further, the effects of NE and EP were also studied in vitro in the presence of specific beta- and alpha-adrenergic antagonists (propranolol and prazosin). NE, EP and corticosterone, when administered in vivo or in vitro, significantly stimulated the respiratory rate of the tissues of both the species irrespective of the seasons/temperature. Results suggest that NE, EP and corticosterone are directly involved in regulation of the energy metabolism of both hibernating and non-hibernating species of sub-tropical frogs. The calorigenic action of NE and EP seems to be mediated by both beta- and alpha-adrenergic receptors. However, the temporal involvement of beta- and alpha-adrenergic receptors seems to be tissue-dependent.

[Effect of UV-B radiation on release of nitrogen and phosphorus from leaf litter in subtropical region in China].

Science.gov (United States)

Song, Xin-Zhang; Zhang, Hui-Ling; Jiang, Hong; Yu, Shu-Quan

2012-02-01

The release of nitrogen and phosphorus from leaf litter of six representative species, Cunninghamia lanceolata, Pinus massoniana, Schima superba, Cinnamanun camphora, Cyclobalanopsis glauca and Castanopsis eyeri, was investigated with litterbag method under ambient and reduced UV-B radiation (22.1% below ambient) treatments in subtropical region. The results showed that, the N dynamics exhibited three patterns: immobilization, mineralization-immobilization and mineralization-immobilization-mineralization. P dynamics also exhibited three different patterns: mineralization, immobilization-mineralization-immobilization and no large change. Compared with ambient treatment, the reduced treatment significantly delayed the N release from C. eyeri and P release from both C. glanca and C. eyeri (Plitter decomposition. The C: P ratios can partly explain the P dynamics during decomposition. The more works need to be done to better understand the role of UV-B radiation in the forest ecosystem in humid subtropical China under global environment change.

Plant Trait Dataset for Tree-Like Growth Forms Species of the Subtropical Atlantic Rain Forest in Brazil

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Arthur Vinicius Rodrigues

2018-05-01

Full Text Available Plant functional traits have been incorporated in studies of vegetation ecology to better understand the mechanisms of ecological processes. For this reason, a global effort has been made to collect functional traits data for as many species as possible. In light of this, we identified the most common species of an area of 15,335 km2 inserted in the subtropical Atlantic Rain Forest in Southern Brazil. Then, we compiled functional trait information mostly from field samples, but also from herbarium and literature. The dataset presents traits of leaf, branch, maximum potential height, seed mass, and dispersion syndrome of 117 species, including trees, tree ferns, and palms. We also share images of anatomical features of branches used to measure wood traits. Data tables present mean trait values at individual and species level. Images of wood and stomatal features may be useful to assess other anatomical traits that were not covered in the data tables for the anatomical determination of species and/or for educational purposes.

Regulation of Light Energy Utilization and Distribution of Photosynthesis in Five Subtropical Woody Plants

Institute of Scientific and Technical Information of China (English)

Nan Liu; Chang-Lian Peng; Zhi-Fang Lin; Gui-Zhu Lin; Xiao-Ping Pan

2007-01-01

The adaptations and responses of photosynthesis to long- and short-term growth light gradient treatments were investigated in five subtropical forest plants, namely Pinus massoniana Lamb., Schima superba Gardn. et Champ.,Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., Acmena acuminatissima (BI.) Merr et Perry, and Cryptocarya concinna Hance. With diurnal changes in sunlight and air temperature, the de-epoxidation state and lutein content in the five woody plants under three light intensifies first increased and then decreased during the day. However,maximal photochemical efficiency (Fv/Fm; where Fm is the maximum fluorescence yield and Fv is variable fluorescence) and the photochemical quantum yields of photosystem (PS) Ⅱ (ΦPSII) of the species examined changed in the opposite manner, with those in plants grown under 100% natural light changing the most. After long-term treatment (21 months), anti-oxidant capacity (1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)-scavenging capacity) and utilization of excitation energy showed differences in modulation by different light intensities. It was shown that A.acuminatissima and C. concinna, as dominant species in the late succession stage of a subtropical forest in Dinghu mountain, South China, were better able to adapt to different light environments. However, P. massoniana, the pioneer species of this forest, exhibited less adaptation to Iow light intensity and was definitely eliminated by the forest successlon process.

Size-dependent responses of zooplankton to submerged macrophyte restoration in a subtropical shallow lake

Science.gov (United States)

Zeng, Lei; He, Feng; Zhang, Yi; Liu, Biyun; Dai, Zhigang; Zhou, Qiaohong; Wu, Zhenbin

2018-03-01

To explore the size-dependent responses of zooplankton to submerged macrophyte restoration, we collected macrophyte, zooplankton and water quality samples seasonally from a subtropical shallow lake from 2010 to 2012. Special attention was given to changes in rotifers and crustaceans (cladocerans and copepods). The rotifers were grouped into three size classes (400 μm) to explore their size-related responses to macrophyte restoration. The results showed that during the restoration, the annual mean biomass and macrophyte coverage increased significantly from 0 to 637 g/m2 and 0 to 27%, respectively. In response, the density and biomass of crustaceans and the crustacean-to-rotifer ratio increased significantly, while the rotifer density decreased significantly. Moreover, rotifers showed significant sizedependent responses to macrophyte restoration. Specially, rotifers sized zooplankton tended to boom, while that of small rotifers was inhibited during macrophyte restoration. Redundancy analysis (RDA) revealed positive correlations between macrophytes and crustaceans, rotifers and COD or Chl- a, but negative correlations between macrophytes and COD or Chl- a, and between crustaceans and Chl- a. Moreover, the results indicate that increased predation on phytoplankton by large-sized zooplankton might be an important mechanism for macrophyte restoration during development of aquatic ecosystems, and that this mechanism played a very important role in promoting the formation of a clear-water state in subtropical shallow lakes.

Forensic use of a subtropical blowfly: the first case indicating minimum postmortem interval (mPMI) in southern Brazil and first record of Sarconesia chlorogaster from a human corpse.

Science.gov (United States)

Vairo, Karine P; Corrêa, Rodrigo C; Lecheta, Melise C; Caneparo, Maria F; Mise, Kleber M; Preti, Daniel; de Carvalho, Claudio J B; Almeida, Lucia M; Moura, Mauricio O

2015-01-01

Southern Brazil is unique due to its subtropical climate. Here, we report on the first forensic entomology case and the first record of Sarconesia chlorogaster (Wiedemann) in a human corpse in this region. Flies' samples were collected from a body indoors at 20°C. Four species were found, but only Chrysomya albiceps (Wiedemann) and S. chlorogaster were used to estimate the minimum postmortem interval (mPMI). The mPMI was calculated using accumulated degree hour (ADH) and developmental time. The S. chlorogaster puparium collected was light in color, so we used an experiment to establish a more accurate estimate for time since initiation of pupation where we found full tanning after 3 h. Development of C. albiceps at 20°C to the end of the third instar is 7.4 days. The mPMI based on S. chlorogaster (developmental time until the third instar with no more than 3 h of pupae development) was 7.6 days. © 2014 American Academy of Forensic Sciences.

MOLECULAR CHARACTERIZATION OF AMERICAN CUTANEOUS LEISHMANIASIS IN THE TRI‑BORDER AREA OF ASSIS BRASIL, ACRE STATE, BRAZIL

Directory of Open Access Journals (Sweden)

Carolina Bioni Garcia TELES

2015-08-01

Full Text Available SUMMARY In this study, Leishmaniaspecies were identified by Polymerase Chain Reaction (PCR. The epidemiology of patients suspected of having American Cutaneous Leishmaniasis in the municipality of Assis Brasil, Acre State, located in the Brazil/Peru/Bolivia triborder was also investigated. By PCR, the DNA of Leishmaniawas detected in 100% of the cases (37 samples and a PCR-Restriction Fragment Length Polymorphism (RFLP of the hsp 70gene identified the species in 32 samples: Leishmania (Viannia braziliensis (65.6% , L. (V. shawi (28.1% , L. (V. guyanensis (3.1% and mixed infection L. (V. guyanensis and L. (Leishmania amazonensis (3.1%This is the first report of L. (V. shawiand L. (L. amazonensis in Acre. The two predominant species were found in patients living in urban and rural areas. Most cases were found in males living in rural areas for at least three years and involved in rural work. This suggests, in most cases, a possible transmission of the disease from a rural/forest source, although some patients had not engaged in activities associated with permanence in forestall areas, which indicate a possible sandflies adaptation to the periurban setting.

Determinants of Tree Assemblage Composition at the Mesoscale within a Subtropical Eucalypt Forest

Science.gov (United States)

Hero, Jean-Marc; Butler, Sarah A.; Lollback, Gregory W.; Castley, James G.

2014-01-01

A variety of environmental processes, including topography, edaphic and disturbance factors can influence vegetation composition. The relative influence of these patterns has been known to vary with scale, however, few studies have focused on environmental drivers of composition at the mesoscale. This study examined the relative importance of topography, catchment flow and soil in influencing tree assemblages in Karawatha Forest Park; a South-East Queensland subtropical eucalypt forest embedded in an urban matrix that is part of the Terrestrial Ecosystem Research Network South-East Queensland Peri-urban SuperSite. Thirty-three LTER plots were surveyed at the mesoscale (909 ha), where all woody stems ≥1.3 m high rooted within plots were sampled. Vegetation was divided into three cohorts: small (≥1–10 cm DBH), intermediate (≥10–30 cm DBH), and large (≥30 cm DBH). Plot slope, aspect, elevation, catchment area and location and soil chemistry and structure were also measured. Ordinations and smooth surface modelling were used to determine drivers of vegetation assemblage in each cohort. Vegetation composition was highly variable among plots at the mesoscale (plots systematically placed at 500 m intervals). Elevation was strongly related to woody vegetation composition across all cohorts (R2: 0.69–0.75). Other topographic variables that explained a substantial amount of variation in composition were catchment area (R2: 0.43–0.45) and slope (R2: 0.23–0.61). Soil chemistry (R2: 0.09–0.75) was also associated with woody vegetation composition. While species composition differed substantially between cohorts, the environmental variables explaining composition did not. These results demonstrate the overriding importance of elevation and other topographic features in discriminating tree assemblage patterns irrespective of tree size. The importance of soil characteristics to tree assemblages was also influenced by topography, where ridge top sites were

Two-step upflow anaerobic sludge bed system for sewage treatment under subtropical conditions with posttreatment in waste stabilization ponds

NARCIS (Netherlands)

Seghezzo, L.; Trupiano, A.P.; Liberal, V.; Todd, P.G.; Figueroa, M.E.; Gutierrez, M.A.; Silva Wilches, Da A.C.; Iribarnegaray, M.; Guerra, R.G.; Arena, A.; Cuevas, C.M.; Zeeman, G.; Lettinga, G.

2003-01-01

A pilot-scale sewage treatment system consisting of two upflow anaerobic sludge bed (UASB) reactors followed by five waste stabilization ponds (WSPs) in series was studied under subtropical conditions. The first UASB reactor started up in only 1 mo (stable operation, high chemical oxygen demand

Prevalence of Clonorchis sinensis infection in dogs and cats in subtropical southern China

Directory of Open Access Journals (Sweden)

Chen Mu-Xin

2011-09-01

Full Text Available Abstract Background Clonorchiasis, caused by Clonorchis sinensis, is one of the major parasitic zoonoses in China, particularly in China's southern Guangdong province where the prevalence of C. sinensis infection in humans is high. However, little is known of the prevalence of C. sinensis infection in its reservoir hosts dogs and cats. Hence, the prevalence of C. sinensis infection in dogs and cats was investigated in Guangdong province, China between October 2006 and March 2008. Results A total of 503 dogs and 194 cats from 13 administrative regions in Guangdong province were examined by post-mortem examination. The worms were examined, counted, and identified to species according to existing keys and descriptions. The average prevalences of C. sinensis infection in dogs and cats were 20.5% and 41.8%, respectively. The infection intensities in dogs were usually light, but in cats the infection intensities were more serious. The prevalences were higher in some of the cities located in the Pearl River Delta region which is the most important endemic area in Guangdong province, but the prevalences were relatively lower in seaside cities. Conclusions The present investigation revealed a high prevalence of C. sinensis infection in its reservoir hosts dogs and cats in China's subtropical Guangdong province, which provides relevant "base-line" data for conducting control strategies and measures against clonorchiasis in this region.

Prevalence of Clonorchis sinensis infection in dogs and cats in subtropical southern China

Science.gov (United States)

2011-01-01

Background Clonorchiasis, caused by Clonorchis sinensis, is one of the major parasitic zoonoses in China, particularly in China's southern Guangdong province where the prevalence of C. sinensis infection in humans is high. However, little is known of the prevalence of C. sinensis infection in its reservoir hosts dogs and cats. Hence, the prevalence of C. sinensis infection in dogs and cats was investigated in Guangdong province, China between October 2006 and March 2008. Results A total of 503 dogs and 194 cats from 13 administrative regions in Guangdong province were examined by post-mortem examination. The worms were examined, counted, and identified to species according to existing keys and descriptions. The average prevalences of C. sinensis infection in dogs and cats were 20.5% and 41.8%, respectively. The infection intensities in dogs were usually light, but in cats the infection intensities were more serious. The prevalences were higher in some of the cities located in the Pearl River Delta region which is the most important endemic area in Guangdong province, but the prevalences were relatively lower in seaside cities. Conclusions The present investigation revealed a high prevalence of C. sinensis infection in its reservoir hosts dogs and cats in China's subtropical Guangdong province, which provides relevant "base-line" data for conducting control strategies and measures against clonorchiasis in this region. PMID:21929783

Testing Dragonflies as Species Richness Indicators in a Fragmented Subtropical Atlantic Forest Environment.

Science.gov (United States)

Renner, S; Sahlén, G; Périco, E

2016-06-01

We surveyed 15 bodies of water among remnants of the Atlantic Forest biome in southern Brazil for adult dragonflies and damselflies to test whether an empirical selection method for diversity indicators could be applied in a subtropical ecosystem, where limited ecological knowledge on species level is available. We found a regional species pool of 34 species distributed in a nested subset pattern with a mean of 11.2 species per locality. There was a pronounced difference in species composition between spring, summer, and autumn, but no differences in species numbers between seasons. Two species, Homeoura chelifera (Selys) and Ischnura capreolus (Hagen), were the strongest candidates for regional diversity indicators, being found only at species-rich localities in our surveyed area and likewise in an undisturbed national forest reserve, serving as a reference site for the Atlantic Forest. Using our selection method, we found it possible to obtain a tentative list of diversity indicators without having detailed ecological information of each species, providing a reference site is available for comparison. The method thus allows for indicator species to be selected in blanco from taxonomic groups that are little known. We hence argue that Odonata can already be incorporated in ongoing assessment programs in the Neotropics, which would also increase the ecological knowledge of the group and allow extrapolation to other taxa.

Changes of Dietary Pattern, Food Choice, Food Consumption, Nutrient Intake and Body Mass Index of Korean American College Students with Different Length of Residence in the Los Angeles Areas

Science.gov (United States)

Kim, Nam; Tam, Chick F.; Poon, George; Lew, Polong; Kim, Samuel Saychang; Kim, James C.; Kim, Rachel Byungsook

2010-01-01

This study was to investigate how dietary pattern, food choice, food consumption, nutrient intake and body mass index (BMI) vary with length of residence for Korean American college students. The respondents were 60 Korean American residents living in the Los Angeles Area. They were divided into two groups based on the length of stay in the U.S.:…

Sino-American Corporation in Peru

Institute of Scientific and Technical Information of China (English)

Wang Mingcai; Xu Yunming

1996-01-01

@@ Sino-American Oil Development Corporation (hereinafter referred to as"SODC") has taken part in the international operation activities in petroleum exploration and development in Latin-American area since 1992 and some progress has been made. At present, SODC is carrying out the operations within the Sixth and Seventh Blocks of Tarara oil field of the Republic of Peru and gains a good prestige.

Marine boundary layer over the subtropical southeast Pacific during VOCALS-REx – Part 2: Synoptic variability

Directory of Open Access Journals (Sweden)

D. A. Rahn

2010-05-01

Full Text Available In the second part of this work we study the day-to-day variability of the marine atmospheric boundary layer (MBL over the subtropical southeast Pacific using primarily results from a numerical simulation that covered the whole VOCALS-REx period (October–November 2008. In situ and satellite-derived observations of the MBL height in the offshore region indicate rapid, significant variations (from 500 m to 1700 m a.s.l. over a few days during October. These MBL changes are connected with the passage of midlatitude troughs that altered the large-scale environment over the VOCALS-REx region. In contrast, the synoptic forcing and MBL changes were less prominent during November. Modelled and observed MBL depth at Point Omega (20° S, 85° W compare quite well during October (but the simulation is on average 200 m lower while in November the simulation does not perform as well.

In the prognostic local MBL height equation the height change, the horizontal MBL height advection, and the large scale vertical velocity at MBL top are calculated explicitly from the simulation. The entrainment velocity is calculated as the residual of the other terms in the equation. While the vertical velocity and residual terms are opposing and generally have the largest magnitude on average, it is the variability in the advection that explains most of the large changes in the MBL depth. Examination of several cases during VOCALS-REx suggests that the advective term is in turn largely controlled by changes in wind direction, driven by midlatitude activity, acting on a MBL that generally slopes down toward the coast. In one phase, the subtropical anticyclone is reinforced and extends toward the Chilean coast, leading to easterly wind that advects low MBL heights from the coast as far as Point Omega. The opposite phase occurs after the passage of an extratropical cyclone over southern Chile, leading to southwesterly wind that advects a deeper MBL towards subtropical

Mitigation of pedestrian heat stress using parasols in a humid subtropical region

Science.gov (United States)

Watanabe, Shinichi; Ishii, Jin

2017-11-01

Concerns over heat illness have been an increasing social problem in humid subtropical regions. One measure for avoiding excessive heat stress in hot outdoor environments is the use of parasols or umbrellas. The advantage of parasols is that they are a mobile and inexpensive way to provide personal shade outdoors. The objectives of this study were to compare the wet-bulb globe temperature (WBGT) under parasols and at an unshaded point as a reference, and to quantify the reduction in WBGT from the use of parasols in a humid subtropical region. Measurements using three parasols of different colors and materials were conducted at the athletics field at Daido University, Nagoya, Japan, between 9:00 and 15:00 Japan Standard Time in August 2015. The WBGT was obtained at heights of 0.1 m (ankles), 1.1 m (abdomen), and 1.7 m (head) above ground, according to the measurement procedure described in ISO 7243. On a sunny and partly cloudy day, the use of a parasol lowered the average globe temperature by up to 6.2 °C, through blocking direct solar radiation. The average reduction in WBGT by the parasol was found to be 1.8 °C at head level in sunny conditions with solar radiation of over 800 W/m2. The reduction in WBGT at head level by the use of parasols in sunny conditions was greater than that in cloudy conditions. However, although parasols can reduce WBGT at the head level of the user regardless of solar radiation, they cannot reduce it at the level of the abdomen or ankles.

A model of seasonal foliage dynamics of the subtropical mangrove species Rhizophora stylosa Griff. growing at the northern limit of its distribution

Directory of Open Access Journals (Sweden)

Sahadev Sharma

2014-08-01

Full Text Available Background Progress of forest production in response to the environment requires a quantitative understanding of leaf area development. Therefore, it is necessary to investigate the dynamics of seasonal crown foliage in order to understand the productivity of mangroves, which play an important role in the subtropical and tropical coastlines of the world. Method Crown foliage dynamics of the mangrove Rhizophora stylosa were studies to reveal patterns of leaf recruitment, survival and seasonal leaf area growth. Results Flushing of leaves occurred throughout the year, but both flushing and leaf area growth pattern of leaves varied with season. Maximum flushing occurred in summer, but leaf areas did not differ significantly with season. The half-expansion period is longer, and the intrinsic rate of increase was lower in winter. Summer flushed leaves grew faster at their initial stage and reached their maximum area over a shorter period of time. The difference in temperature and air vapor pressure deficit (VPD between summer and winter contributed to the present dynamics of foliage patterns. The mean leaf longevity was estimated to be 13.1 month. The crown foliage area was almost stable throughout the year. Conclusions Homeostatic control of the crown foliage area may be accompanied by the existence of ecophysiological mechanisms in R. stylosa. Integrating crown foliage dynamics into forest models represents an important step towards incorporating physiological mechanisms into the models for predicting growth responses to environmental changes and for understanding the complex responses of tree growth and litter production.

The Use of a Geographic Information System and Remote Sensing Technology for Monitoring Land Use and Soil Carbon Change in the Subtropical Dry Forest Life Zone of Puerto Rico

Science.gov (United States)

Velez-Rodriguez, Linda L. (Principal Investigator)

1996-01-01

Aerial photography, one of the first form of remote sensing technology, has long been an invaluable means to monitor activities and conditions at the Earth's surface. Geographic Information Systems or GIS is the use of computers in showing and manipulating spatial data. This report will present the use of geographic information systems and remote sensing technology for monitoring land use and soil carbon change in the subtropical dry forest life zone of Puerto Rico. This research included the south of Puerto Rico that belongs to the subtropical dry forest life zone. The Guanica Commonwealth Forest Biosphere Reserve and the Jobos Bay National Estuarine Research Reserve are studied in detail, because of their location in the subtropical dry forest life zone. Aerial photography, digital multispectral imagery, soil samples, soil survey maps, field inspections, and differential global positioning system (DGPS) observations were used.

Endangered Species and North American Waterfowl Management Plan Joint Venture Areas

National Research Council Canada - National Science Library

Allred, Karla

1996-01-01

...) Endangered Species Recovery Plans that meet the recovery plan requirements; and the percent of Corps acreage included within North American Waterfowl Management Joint Venture Implementation Plans where proposed work has been accomplished...

A Research Note on American Indian Criminal Justice

Science.gov (United States)

Braunstein, Rich; Anderson, Bill

2008-01-01

One confronts many difficulties when conducting policy-relevant criminal justice research that focuses on American Indian interests. Foremost among these difficulties is the great variation in relevant contexts that apply to this area of research. From the urban context of large American cities, where American Indians constitute a slim minority…

Impact of the North American Free Trade Agreement on transportation in the border areas of the United States : with emphasis on the California-Mexico border

Science.gov (United States)

1999-08-01

This report identifies impacts of the North ?American Free Trade Agreement (NAFTA) on transportation in the U.S. border areas. Emphasis is on the California-Baja California border zone. Focus is on the identification of recommendations to the Califor...

Plastic pollution in the South Pacific subtropical gyre.

Science.gov (United States)

Eriksen, Marcus; Maximenko, Nikolai; Thiel, Martin; Cummins, Anna; Lattin, Gwen; Wilson, Stiv; Hafner, Jan; Zellers, Ann; Rifman, Samuel

2013-03-15

Plastic marine pollution in the open ocean of the southern hemisphere is largely undocumented. Here, we report the result of a (4489 km) 2424 nautical mile transect through the South Pacific subtropical gyre, carried out in March-April 2011. Neuston samples were collected at 48 sites, averaging 50 nautical miles apart, using a manta trawl lined with a 333 μm mesh. The transect bisected a predicted accumulation zone associated with the convergence of surface currents, driven by local winds. The results show an increase in surface abundance of plastic pollution as we neared the center and decrease as we moved away, verifying the presence of a garbage patch. The average abundance and mass was 26,898 particles km(-2) and 70.96 g km(-2), respectively. 88.8% of the plastic pollution was found in the middle third of the samples with the highest value of 396,342 particles km(-2) occurring near the center of the predicted accumulation zone. Copyright © 2013 Elsevier Ltd. All rights reserved.

[American cutaneous leishmaniasis: phlebotomine transmission area in the Municipality of Uberlândia, MG].

Science.gov (United States)

Lemos, Jureth Couto; Lima, Samuel do Carmo

2005-01-01

From May 2000 to January 2001 four, 15 hour-long collections of phlebotomine were done to the insect monitoring. The collection was done in an area of infection of American cutaneous leishmaniasis in the basin of the Araguari River in the municipality of Uberlandia (MG). The first collection was made in May (a cold, damp month), the second in June 2000 (a cold, dry month) the third in October 2000 (a hot, dry month) and the fourth in January 2001 (a hot, rainy month). CDC and Shannon light traps were used 6551 phlebotomne were captured and identified, 1990 male and 4562 female, comprised of two lines (Lutzomyia and Brumptomyia) and 8 species. Lutzomyia intermedia predominated with the largest number of specimens (6531), which accounted for 99.7% of the collected insects. In the four collections, it was observed that Lutzomyia intermedia manifested a preference for the month preceding the rainy season, with its high temperatures and humidity.

32 CFR Appendix A to Part 552 - DPCA Recreational Areas in Training Areas

Science.gov (United States)

2010-07-01

... guests. Boat launch adjacent to Officer's Club Beach on American Lake/Beachwood area Cat Lake Picnic and Fishing Area—Training Area 19 Chambers Lake Picnic and *Fishing Area—Training Area 12 (See para 2 below) Ecology Park Hiking Path—North Fort, CTA A West Fiander Lake Picnic and Fishing Area—Training Area 20...

Astronomically Forced Hydrology of the Late Cretaceous Sub-tropical Potosí Basin, Bolivia

Science.gov (United States)

Tasistro-Hart, A.; Maloof, A. C.; Schoene, B.; Eddy, M. P.

2017-12-01

Orbital forcings paced the ice ages of the Pleistocene, demonstrating that periodic variations in the latitudinal distribution of insolation amplified by ice-albedo feedbacks can guide global climate. How these forcings operate in the hot-houses that span most of the planet's history, however, is unknown. The lacustrine El Molino formation of the late Cretaceous-early Paleogene Potosí Basin in present-day Bolivia contains carbonate-mud parasequences that record fluctuating hydrological conditions from 73 to 63 Ma. This study presents the first cyclostratigraphic analysis using high-resolution drone-derived imagery and 3D elevation models, combined with conventional stratigraphic measurements and magnetic susceptibility data. The drone-derived data are integrated over the entire outcrop at two field areas using a novel application of stratigraphic potential field modeling that increases signal-to-noise ratios prior to spectral analysis. We demonstrate that these parasequences exhibit significant periodicities consistent with eccentricity (400 and 100 kyr), obliquity (50 kyr, 40 kyr, and 29 kyr), precession (17-23 kyr), and semi-precession (9-11 kyr). New U-Pb ID-TIMS zircon ages from intercalacted ash beds corroborate the interpreted sedimentation rates at two sites, indicating that the Potosí Basin contains evidence for hot-house astronomical forcing of sub-tropical lacustrine hydrology. Global climate simulations of late Cretaceous orbital end-member configurations demonstrate precessional-eccentricity and obliquity driven modulation of basin hydrology. In model simulations, the forcings drive long-term shifts in the location of the intertropical convergence zone, changing precipitation along the northern extent of the Potosí Basin's catchment area. This study is the first to demonstrate orbital forcing of a lacustrine system during the Maastrichtian and could ultimately contribute to a precise age for the Cretaceous-Paleogene boundary.

32 CFR Appendix A to Subpart M of... - DPCA Recreational Areas in Training Areas

Science.gov (United States)

2010-07-01

... launch adjacent to Officer's Club Beach on American Lake—Beachwood area Cat Lake Picnic and Fishing Area—Training Area 19 Chambers Lake Picnic and Fishing Area—Training Area 12 (See Para 3 below) Fiander lake Picnic and Fishing Area—Training Area 20 Johnson Marsh—Training Area 10 Lewis Lake Picnic and Fishing...

Balancing Methane Emissions and Carbon Sequestration in Tropical/Subtropical Coastal Wetlands: A Review

Science.gov (United States)

Mitsch, W. J.; Schafer, K. V.; Cabezas, A.; Bernal, B.

2016-02-01

Wetlands are estimated to emit about 20 to 25 percent of current global CH4 emissions, or about 120 to 180 Tg-CH4 yr-1. Thus, in climate change discussions concerning wetlands, these "natural emissions" often receive the most attention, often overshadowing the more important ecosystem services that wetlands provide, including carbon sequestration. While methane emissions from coastal wetlands have generally been described as small due to competing biogeochemical cycles, disturbance of coastal wetlands, e.g., the introduction of excessive freshwater fluxes or substrate disturbance, can lead to much higher methane emission rates. Carbon sequestration is a more positive carbon story about wetlands and coastal wetlands in particular. The rates of carbon sequestration in tropical/subtropical coastal wetlands, mainly mangroves, are in the range of 100 to 200 g-C m-2 yr-1, two to ten times higher rates than in the more frequently studied northern peatlands. This function of coastal wetlands has significant international support now for mangrove conservation and it is referred to in the literature and popular press as blue carbon. This presentation will summarize what we know about methane emissions and carbon sequestration in tropical/subtropical coastal wetlands, how these rates compare with those in non-tropical and/or inland wetlands, and a demonstration of two or three models that compare methane fluxes with carbon dioxide sequestration to determine if wetlands are net sinks of radiative forcing. The presentation will also present a global model of carbon with an emphasis on wetlands.

The college life experiences of African American women athletes.

Science.gov (United States)

Sellers, R M; Kuperminc, G P; Damas, A

1997-10-01

The present study provides a descriptive analysis of four areas of African American women student athletes' college life experiences: academic performance; alienation and abuse; perceived social advantage as the result of athletics; and life satisfaction. Multivariate comparisons were made between the four areas of college life experiences of 154 African American women student athletes and 793 White women student athletes, 250 African American women nonathletes, and 628 African American men student athletes from a national sample of 39 NCAA Division I universities. Overall, African American women student athletes are performing adequately academically, integrating socially within the university, perceiving some social advantage as the result of being athletes, and are fairly satisfied with their life. Their experiences seem most consistent with African American women nonathletes. Results are discussed in the context of potential policy recommendations as well as the need for more research on this particular population.

Effect of urbanization on the structure and functional traits of remnant subtropical evergreen broad-leaved forests in South China

Science.gov (United States)

Liujing Huang; Hongfeng Chen; Hai Ren; Jun Wang; Qinfeng Guo

2013-01-01

We investigated the effects of major environmental drivers associated with urbanization on species diversity and plant functional traits (PFTs) in the remnant subtropical evergreen broad-leaved forests in Metropolitan Guangzhou (Guangdong, China). Twenty environmental factors including topography, light, and soil properties were used to quantify the effects of...

Floristic diversity and vegetation structure of the remnant subtropical broad leaved forests from Kabal valley, Swat, Pakistan

International Nuclear Information System (INIS)

Ilyas, M.; Qureshi, R.; Akhtar, N.

2018-01-01

Under the prevailing anthropogenic and deteriorating environmental conditions, subtropical broad leaved forests in Pakistan are vanishing at a rapid pace. Muslim communities living in rural areas pay great respect and sanctity to the graveyards and avoid interference with the natural vegetation in these sites. The relics of the natural climax plant communities can be seen in the Muslim graveyards of almost every village of Kabal valley, Swat. Little attention has been given to the significance of cultural norms and religious beliefs in conserving phytodiversity. The present endeavor was undertaken to quantify the existing phytodiversity from the studied area during 2010 to 2014. Species and environmental data from 40 releves measuring 10 x 10 m size laid in different Muslim graveyards was stored in TURBOVEG and exported to JUICE for analysis through Two Way Hierarchical Cluster Analysis and Canonical Correspondence Analysis (CCA). The vegetation comprised of an association dominated by Olea ferruginea and Celtis eriocarpa with five distinct communities based on floristic components and environmental variables. Soil moisture, pH, phosphorus, organic matter content and altitude were the main determining factors in establishing these plant communities. The vegetation was stratified with the highest tree layer (17.48+-2.94m), shrub layer (1.85+-0.28m) and herb layer (65.25+-17.79cm). The canopy covered the area about 84.38+-11.83%, of which tree layer shared 69.25+-16.15%, shrub layer 37.63+-11.43% and herb layer56.50+-11.72%. In all, 229 vascular plant species were recorded from the sampled area. Mean species richness was 28.83+-6.69, followed by Shannon index (2.59+-0.32), Simpson index (0.85+-0.06) and evenness index (0.78+-0.07). The significance of indigenous peoples' beliefs and taboos in biodiversity conservation has been discussed in the paper. (author)

Coral reef ecosystem marine protected area monitoring in Fagamalo, American Samoa: comprehensive assessment of coral demography (adult and juvenile corals) from belt transect surveys in 2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In 2010 the village of Fagamalo, Tutuila, American Samoa, designated a no-take Marine Protected Area that sees the protection of 2.25 square kilometers of ocean....

The extreme 2014 flood in south-western Amazon basin: the role of tropical-subtropical South Atlantic SST gradient

International Nuclear Information System (INIS)

Espinoza, Jhan Carlo; Marengo, José Antonio; Ronchail, Josyane; Carpio, Jorge Molina; Flores, Luís Noriega; Guyot, Jean Loup

2014-01-01

Unprecedented wet conditions are reported in the 2014 summer (December–March) in South-western Amazon, with rainfall about 100% above normal. Discharge in the Madeira River (the main southern Amazon tributary) has been 74% higher than normal (58 000 m 3 s −1 ) at Porto Velho and 380% (25 000 m 3 s −1 ) at Rurrenabaque, at the exit of the Andes in summer, while levels of the Rio Negro at Manaus were 29.47 m in June 2014, corresponding to the fifth highest record during the 113 years record of the Rio Negro. While previous floods in Amazonia have been related to La Niña and/or warmer than normal tropical South Atlantic, the 2014 rainfall and flood anomalies are associated with warm condition in the western Pacific-Indian Ocean and with an exceptionally warm Subtropical South Atlantic. Our results suggest that the tropical and subtropical South Atlantic SST gradient is a main driver for moisture transport from the Atlantic toward south-western Amazon, and this became exceptionally intense during summer of 2014. (letter)

What are Hospice Providers in the Carolinas Doing to Reach African Americans in Their Service Area?

Science.gov (United States)

Payne, Richard; Kuchibhatla, Maragatha N.

2016-01-01

Abstract Background: Experts and national organizations recommend that hospices work to increase service to African Americans, a group historically underrepresented in hospice. Objective: The study objective was to describe strategies among hospices in North and South Carolina to increase service to African Americans and identify hospice characteristics associated with these efforts. Methods: The study was a cross-sectional survey using investigator-developed scales to measure frequency of community education/outreach, directed marketing, efforts to recruit African American staff, cultural sensitivity training, and goals to increase service to African Americans. We used nonparametric Wilcoxon tests to compare mean scale scores by sample characteristics. Results: Of 118 eligible hospices, 79 (67%) completed the survey. Over 80% were at least somewhat concerned about the low proportion of African Americans they served, and 78.5% had set goals to increase service to African Americans. Most were engaged in community education/outreach, with 92.4% reporting outreach to churches, 76.0% to social services organizations, 40.5% to businesses, 35.4% to civic groups, and over half to health care providers; 48.0% reported directed marketing via newspaper and 40.5% via radio. The vast majority reported efforts to recruit African American staff, most often registered nurses (63.75%). Nearly 90% offered cultural sensitivity training to staff. The frequency of strategies to increase service to African Americans did not vary by hospice characteristics, such as profit status, size, or vertical integration, but was greater among hospices that had set goals to increase service to African Americans. Conclusions: Many hospices are engaged in efforts to increase service to African Americans. Future research should determine which strategies are most effective. PMID:26840854

Isotopic assessment of soil phosphorus fertility and evaluation of rock phosphates as phosphorus sources for plants in subtropical China

International Nuclear Information System (INIS)

Xiong, L.M.; Zhou, Z.G.; Feng, G.L.; Lu, R.K.; Fardeau, J.C.

2002-01-01

Soil phosphorus (P) deficiency is a major factor limiting crop productivity in many tropical and subtropical soils. Due to the acidic nature of these soils, rock phosphate (RP)-based P fertilizers that are cheaper than manufactured water-soluble P fertilizers can be an attractive alternative under certain conditions. Assessment of the efficacy of these alternative P fertilizers and a rational management of local P resources for sustainable agricultural production require an understanding of the dynamics of P in the soil-plant system and the interactions of various P sources in soils and monitoring of soil available P levels. The present work was conducted to test the applicability of the 32 P isotopic kinetic method to assess the soil P fertility status and evaluate the agronomic effectiveness of local rock phosphates in subtropical China. A series of experiments was carried out in the laboratory, greenhouse and field conditions with the following specific objectives: (a) to evaluate the suitability of this isotopic kinetic method in evaluating soil P fertility in 32 soil samples collected across southern China, (b) to test and further develop chemical extraction methods for routine soil P testing, (c) to monitor the dissolution kinetics of local low to medium grade rock phosphate sources and their effect on soil properties and (d) to evaluate their agronomic effectiveness in greenhouse and field experiments. Since most of the studied soils had very low concentrations of soluble P and high P-fixing capacities, the isotopic kinetic method was found unsuitable for evaluating soil P fertility and to predict plant P uptake. In contrast, the proposed chemical extraction method (NaHCO 3 -NH 4 F) predicted very well plant P uptake, suggesting that this extraction method can be routinely used to evaluate soil bioavailable P in similar soils in subtropical China. From the incubation study, it was found that although the local low to medium grade RPs were inferior to the

Analyzing Multidecadal Trends in Cloudiness Over the Subtropical Andes Mountains of South America Using a Regional Climate Model.

Science.gov (United States)

Zaitchik, B. F.; Russell, A.; Gnanadesikan, A.

2016-12-01

Satellite-based products indicate that many parts of South America have been experiencing increases in outgoing longwave radiation (OLR) and corresponding decreases in cloudiness over the last few decades, with the strongest trends occurring in the subtropical Andes Mountains - an area that is highly vulnerable to climate change due to its reliance on glacial melt for dry-season runoff. Changes in cloudiness may be contributing to increases in atmospheric temperature, thereby raising the freezing level height (FLH) - a critical geophysical parameter. Yet these trends are only partially captured in reanalysis products, while AMIP climate models generally show no significant trend in OLR over this timeframe, making it difficult to determine the underlying drivers. Therefore, controlled numerical experiments with a regional climate model are performed in order to investigate drivers of the observed OLR and cloudiness trends. The Weather Research and Forecasting model (WRF) is used here because it offers several advantages over global models, including higher resolution - a critical asset in areas of complex topography - as well as flexible physics, parameterization, and data assimilation capabilities. It is likely that changes in the mean states and meridional gradients of SSTs in the Pacific and Atlantic oceans are driving regional trends in clouds. A series of lower boundary manipulations are performed with WRF to determine to what extent changes in SSTs influence regional OLR.

[Floristic composition and distribution of the Andean subtropical riparian forests of Lules River, Tucuman, Argentina].

Science.gov (United States)

Sirombra, Martín G; Mesa, Leticia M

2010-03-01

We studied the floristic composition and distribution of the riparian forest of two hydrographical systems in a subtropical Andean region. Using uni and multivariate techniques, we tested the hypotheses that a differentiable riparian forest exists, composed by native vegetation typical of the Yungas phytogeographical province, and that the distribution of vegetation varied significantly with geomorphologic characteristics. Parallel transects along the water courses were used to collect presence-absence data of vegetation in eleven sites. Detrended Correspondence Analysis defined a group of common riparian species for the studied area (Solanum riparium, Phenax laevigatus, Tipuana tipu, Cestrum parqui, Carica quercifolia, Acacia macracantha, Celtis iguanaea, Juglans australis, Pisoniella arborescens, Baccharis salicifolia, Cinnamomum porphyrium and Eugenia uniflora) and identified two reference sites. The distribution of the riparian vegetation varied significantly with the geomorphic characteristics along the studied sites. Riparian habitats were composed by native and exotic species. A distinct riparian flora, different in structure and function from adjacent terrestrial vegetation, could not be identified. Riparian species were similar to the adjacent terrestrial strata. These species would not be limited by the proximity to the river. Anthropogenic impacts were important factors regulating the introduction and increase of exotic vegetation. The lack of regulation of some activities in the zone could cause serious problems in the integrity of this ecosystem.

Co-existence of freshwater and marine T4-like myoviruses in a typical subtropical estuary.

Science.gov (United States)

Liu, Lu; Cai, Lanlan; Zhang, Rui

2017-11-01

Viruses are the most abundant biological entities on Earth and play an important role in microbial community dynamics and biogeochemical cycling, yet their ecological characteristics in estuarine ecosystems are unclear. Here, virioplankton communities in a typical subtropical estuary, the Jiulong River estuary (JRE) in China, were investigated. The abundance of virioplankton ranged from 1.01 ± 0.05 × 107 to 1.62 ± 0.09 × 107 particles mL-1 in JRE, and the population size of viruses was correlated with temperature and nutrient levels. Three tailed viral morphotypes (myovirus, siphovirus and podovirus) were observed. Phylogenetic analysis showed that most of the g23 sequences in the JRE fell into three previously established groups (Marine, Paddy and Lake Groups) and two potential Estuary Groups. This demonstrates the co-existence of typical freshwater and marine T4-like myoviruses in the estuarine ecosystem, suggesting the movement of viruses and their hosts among biomes. Additionally, the spatial variation of g23 sequences suggests a geographic distribution pattern of T4-like myoviruses in the JRE, which might be shaped by the environmental gradient and/or their host distribution. These results provide valuable insights into the abundance, diversity and distribution patterns of virioplankton, as well as the factors influencing them, in subtropical estuarine ecosystems. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

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A. Goldner

2011-07-01

Full Text Available Substantial evidence exists for wetter-than-modern continental conditions in North America during the pre-Quaternary warm climate intervals. This is in apparent conflict with the robust global prediction for future climate change of a northward expansion of the subtropical dry zones that should drive aridification of many semiarid regions. Indeed, areas of expected future aridification include much of western North America, where extensive paleoenvironmental records are documented to have been much wetter before the onset of Quaternary ice ages. It has also been proposed that climates previous to the Quaternary may have been characterized as being in a state with warmer-than-modern eastern equatorial sea surface temperatures (SSTs. Because equatorial Pacific SSTs exert strong controls on midlatitude atmospheric circulation and the global hydrologic cycle, the teleconnected response from this permanent El Niño-like mean state has been proposed as a useful analogue model, or "blueprint", for understanding global climatological anomalies in the past. The present study quantitatively explores the implications of this blueprint for past climates with a specific focus on the Miocene and Pliocene, using a global climate model (CAM3.0 and a nested high-resolution climate model (RegCM3 to study the hydrologic impacts on global and North American climate of a change in mean SSTs resembling that which occurs during modern El Niño events. We find that the global circulation response to a permanent El Niño resembles a large, long El Niño event. This state also exhibits equatorial super-rotation, which would represent a fundamental change to the tropical circulations. We also find a southward shift in winter storm tracks in the Pacific and Atlantic, which affects precipitation and temperature over the mid-latitudes. In addition, summertime precipitation increases over the majority of the continental United States. These increases in precipitation are

Rapid City Native American Population Needs Assessment.

Science.gov (United States)

Farrokhi, Abdollah

1993-01-01

Interviews with 301 Native American households in Rapid City, South Dakota, examined demographic variables and attitudes and needs in the areas of education, housing, transportation, health care, recreation, and employment. The ultimate goals for Native American people are achieving empowerment and group determination through greater cultural…

Sixty-two years of change in subtropical wet forest structure and composition at El Verde, Puerto Rico

Science.gov (United States)

A.P. Drew; J.D. Boley; Y. Zhao; F.H. Wadsworth

2009-01-01

A plot established in 1943 in a subtropical wet forest at the Luquillo Experimental Forest of Puerto Rico has been assessed periodically for changes in species and size of all trees >4cm diameter. Forest dynamics on a 0.72ha plot (EV-3) at 400masl at El Verde show recovery principally from hurricanes of 1928 and 1932, timber stand improvement in 1958, and from...

Urbanization effects on leaf litter decomposition, foliar nutrient dynamics and aboveground net primary productivity in the subtropics

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Heather A. Enloe; B. Graeme Lockaby; Wayne C. Zipperer; Greg L. Somers

2015-01-01

Urbanization can alter nutrient cycling. This research evaluated how urbanization affected nutrient dynamics in the subtropics. We established 17–0.04 ha plots in five different land cover types—slash pine (Pinus elliottii) plantations (n=3), rural natural pine forests (n= 3), rural natural oak forests (n=4), urban pine forests (n=3) and urban oak forests (n=4) in the...

The Relationship between Native American Ancestry, Body Mass Index and Diabetes Risk among Mexican-Americans.

Science.gov (United States)

Hu, Hao; Huff, Chad D; Yamamura, Yuko; Wu, Xifeng; Strom, Sara S

2015-01-01

Higher body mass index (BMI) is a well-established risk factor for type 2 diabetes, and rates of obesity and type 2 diabetes are substantially higher among Mexican-Americans relative to non-Hispanic European Americans. Mexican-Americans are genetically diverse, with a highly variable distribution of Native American, European, and African ancestries. Here, we evaluate the role of Native American ancestry on BMI and diabetes risk in a well-defined Mexican-American population. Participants were randomly selected among individuals residing in the Houston area who are enrolled in the Mexican-American Cohort study. Using a custom Illumina GoldenGate Panel, we genotyped DNA from 4,662 cohort participants for 87 Ancestry-Informative Markers. On average, the participants were of 50.2% Native American ancestry, 42.7% European ancestry and 7.1% African ancestry. Using multivariate linear regression, we found BMI and Native American ancestry were inversely correlated; individuals with ancestry were 2.5 times more likely to be severely obese compared to those with >80% Native American ancestry. Furthermore, we demonstrated an interaction between BMI and Native American ancestry in diabetes risk among women; Native American ancestry was a strong risk factor for diabetes only among overweight and obese women (OR = 1.190 for each 10% increase in Native American ancestry). This study offers new insight into the complex relationship between obesity, genetic ancestry, and their respective effects on diabetes risk. Findings from this study may improve the diabetes risk prediction among Mexican-American individuals thereby facilitating targeted prevention strategies.

Cloud Cover Assessment for Operational Crop Monitoring Systems in Tropical Areas

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Isaque Daniel Rocha Eberhardt

2016-03-01

Full Text Available The potential of optical remote sensing data to identify, map and monitor croplands is well recognized. However, clouds strongly limit the usefulness of optical imagery for these applications. This paper aims at assessing cloud cover conditions over four states in the tropical and sub-tropical Center-South region of Brazil to guide the development of an appropriate agricultural monitoring system based on Landsat-like imagery. Cloudiness was assessed during overlapping four months periods to match the typical length of crop cycles in the study area. The percentage of clear sky occurrence was computed from the 1 km resolution MODIS Cloud Mask product (MOD35 considering 14 years of data between July 2000 and June 2014. Results showed high seasonality of cloud occurrence within the crop year with strong variations across the study area. The maximum seasonality was observed for the two states in the northern part of the study area (i.e., the ones closer to the Equator line, which also presented the lowest averaged values (15% of clear sky occurrence during the main (summer cropping period (November to February. In these locations, optical data faces severe constraints for mapping summer crops. On the other hand, relatively favorable conditions were found in the southern part of the study region. In the South, clear sky values of around 45% were found and no significant clear sky seasonality was observed. Results underpin the challenges to implement an operational crop monitoring system based solely on optical remote sensing imagery in tropical and sub-tropical regions, in particular if short-cycle crops have to be monitored during the cloudy summer months. To cope with cloudiness issues, we recommend the use of new systems with higher repetition rates such as Sentinel-2. For local studies, Unmanned Aircraft Vehicles (UAVs might be used to augment the observing capability. Multi-sensor approaches combining optical and microwave data can be another

Dynamics of ecosystem services provided by subtropical forests in Southeast China during succession as measured by donor and receiver value

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The trends in the provision of ecosystem services during restoration and succession of subtropical forests and plantations were quantified, in terms of both receiver and donor values, based on a case study of a 3-step secondary succession series that included a 400-year-old subtr...

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Science.gov (United States)

Lizotte, Martine; Levasseur, Maurice; Law, Cliff S.; Walker, Carolyn F.; Safi, Karl A.; Marriner, Andrew; Kiene, Ronald P.

2017-11-01

The oceanic frontal region above the Chatham Rise east of New Zealand was investigated during the late austral summer season in February and March 2012. Despite its potential importance as a source of marine-originating and climate-relevant compounds, such as dimethyl sulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP), little is known of the processes fuelling the reservoirs of these sulfur (S) compounds in the water masses bordering the subtropical front (STF). This study focused on two opposing short-term fates of DMSP-S following its uptake by microbial organisms (either its conversion into DMS or its assimilation into bacterial biomass) and has not considered dissolved non-volatile degradation products. Sampling took place in three phytoplankton blooms (B1, B2, and B3) with B1 and B3 occurring in relatively nitrate-rich, dinoflagellate-dominated subantarctic waters, and B2 occurring in nitrate-poor subtropical waters dominated by coccolithophores. Concentrations of total DMSP (DMSPt) and DMS were high across the region, up to 160 and 14.5 nmol L-1, respectively. Pools of DMSPt showed a strong association with overall phytoplankton biomass proxied by chlorophyll a (rs = 0.83) likely because of the persistent dominance of dinoflagellates and coccolithophores, both DMSP-rich taxa. Heterotrophic microbes displayed low S assimilation from DMSP (less than 5 %) likely because their S requirements were fulfilled by high DMSP availability. Rates of bacterial protein synthesis were significantly correlated with concentrations of dissolved DMSP (DMSPd, rs = 0.86) as well as with the microbial conversion efficiency of DMSPd into DMS (DMS yield, rs = 0.84). Estimates of the potential contribution of microbially mediated rates of DMS production (0.1-27 nmol L-1 day-1) to the near-surface concentrations of DMS suggest that bacteria alone could not have sustained DMS pools at most stations, indicating an important role for phytoplankton-mediated DMS

Shifting nitrous oxide source/sink behaviour in a subtropical estuary revealed by automated time series observations

Science.gov (United States)

Reading, Michael J.; Santos, Isaac R.; Maher, Damien T.; Jeffrey, Luke C.; Tait, Douglas R.

2017-07-01

The oceans are a major source of the potent greenhouse gas nitrous oxide (N2O) to the atmosphere. However, little information is available on how estuaries and the coastal ocean may contribute to N2O budgets, and on the drivers of N2O in aquatic environments. This study utilised five time series stations along the freshwater to marine continuum in a sub-tropical estuary in Australia (Coffs Creek, Australia). Each time series station captured N2O, radon (222Rn, a natural submarine groundwater discharge tracer), dissolved nitrogen, and dissolved organic carbon (DOC) concentrations for a minimum of 25 h. The use of automated time series observations enabled spatial and tidal-scale variability of N2O to be captured. Groundwater was highly enriched in N2O (up to 306 nM) compared to the receiving surface water. Dissolved N2O supersaturation as high as 386% (27.4 nM) was observed in the upstream freshwater and brackish water areas which represented only a small (∼13%) proportion of the total estuary area. A large area of N2O undersaturation (as low as 53% or 3.9 nM) was observed in the mangrove-dominated lower estuary. This undersaturated area likely resulted from N2O consumption due to nitrate/nitrite (NOx) limitation in mangrove sediments subject to shallow porewater exchange. Overall, the estuary was a minor source of N2O to the atmosphere as the lower mangrove-dominated estuary sink of N2O counteracted groundwater-dominated source of N2O in the upper estuary. Average area-weighted N2O fluxes at the water-air interface approached zero (0.2-0.7 μmol m-2 d-1, depending on piston velocity model used), and were much lower than nitrogen-rich Northern Hemisphere estuaries that are considered large sources of N2O to the atmosphere. This study revealed a temporally and spatially diverse estuary, with areas of N2O production and consumption related to oxygen and total dissolved nitrogen availability, submarine groundwater discharge, and uptake within mangroves.

Microbiome of Trichodesmium Colonies from the North Pacific Subtropical Gyre

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Mary R. Gradoville

2017-07-01

Full Text Available Filamentous diazotrophic Cyanobacteria of the genus Trichodesmium, often found in colonial form, provide an important source of new nitrogen to tropical and subtropical marine ecosystems. Colonies are composed of several clades of Trichodesmium in association with a diverse community of bacterial and eukaryotic epibionts. We used high-throughput 16S rRNA and nifH gene sequencing, carbon (C and dinitrogen (N2 fixation assays, and metagenomics to describe the diversity and functional potential of the microbiome associated with Trichodesmium colonies collected from the North Pacific Subtropical Gyre (NPSG. The 16S rRNA and nifH gene sequences from hand-picked colonies were predominantly (>99% from Trichodesmium Clade I (i.e., T. thiebautii, which is phylogenetically and ecologically distinct from the Clade III IMS101 isolate used in most laboratory studies. The bacterial epibiont communities were dominated by Bacteroidetes, Alphaproteobacteria, and Gammaproteobacteria, including several taxa with a known preference for surface attachment, and were relatively depleted in the unicellular Cyanobacteria and small photoheterotrophic bacteria that dominate NPSG surface waters. Sequencing the nifH gene (encoding a subcomponent of the nitrogenase enzyme identified non-Trichodesmium diazotrophs that clustered predominantly among the Cluster III nifH sequence-types that includes putative anaerobic diazotrophs. Trichodesmium colonies may represent an important habitat for these Cluster III diazotrophs, which were relatively rare in the surrounding seawater. Sequence analyses of nifH gene transcripts revealed several cyanobacterial groups, including heterocystous Richelia, associated with the colonies. Both the 16S rRNA and nifH datasets indicated strong differences between Trichodesmium epibionts and picoplankton in the surrounding seawater, and also between the epibionts inhabiting Trichodesmium puff and tuft colony morphologies. Metagenomic and 16S r

Seagrass community dynamics in a subtropical estuarine lagoon

Energy Technology Data Exchange (ETDEWEB)

Thorhaug, A.; Roessler, M.A.

1977-11-01

The temporal and spatial distributions of major plant and animal species were investigated for 4 years in south Biscayne Bay including Card Sound, Florida, a subtropical estuarine lagoon. This was part of a larger study including chemical, physical and geological investigations. The major species of plants were Thalassia testudinum Banks ex Konig, turtle grass, Laurencia poitei (Lamour.) Howe, a red macroalga and the green algae Penicillus capitatus Lamarck and Halimeda incrassata (Ellis) Lamour. Standing crop and production of plant material taken bi-weekly is given in detail for 16 stations in Card Sound for the 4-year period and for eight stations in Biscayne Bay for a 1-year period. The major animal species were not equally distributed; in the near-shore Thalassia community, species of Pagurus, Neopanope, Hippolyte, Cerithium, Bulla, Prunum and Modulus were dominant. In mid-bay, where patchy Thalassia plus green algae occurred, Thor and Chondrilla were the dominant animals. Near the fringing islands, where tidal flow caused more oceanic conditions, the community was dominated by sponges, urchins and corals. This highlights the structural differences in what is now termed the ''Thalassia community.'' Comparisons with other known Thalassia communities are made.

An integrated evaluation of molecular marker indices and linear alkylbenzenes (LABs) to measure sewage input in a subtropical estuary (Babitonga Bay, Brazil)

International Nuclear Information System (INIS)

Martins, César C.; Cabral, Ana Caroline; Barbosa-Cintra, Scheyla C.T.; Dauner, Ana Lúcia L.; Souza, Fernanda M.

2014-01-01

Babitonga Bay is a South Atlantic estuary with significant ecological function; it is part of the last remaining areas of mangrove communities in the Southern Hemisphere. The aim of this study was to determine the spatial distribution of the faecal sterols and linear alkylbenzenes (LABs) in surface sediments and to perform an integrated evaluation of several molecular marker indices to assess the sewage contamination status in the study area. The highest observed concentrations of faecal sterols (coprostanol + epicoprostanol) and LABs were 6.65 μg g −1 and 413.3 ng g −1 , respectively. Several faecal sterol indices were calculated and correlated with coprostanol levels; these analyses showed that the index limits presented in the current literature could underestimate the sewage contamination in this study area. For the overall estuarine system, a low sewage impact may be assumed based on the low total mass inventories calculated for coprostanol (between 1.4% and 4.8%). - Highlights: • Sewage contamination in a South Atlantic estuary was confirmed by molecular markers. • Faecal sterol indices were established as indicators of sewage contamination. • Estimates of the total mass inventory of coprostanol and LABs are presented. • Faecal sterols are preferable to LABs for the evaluation of sewage inputs in this study area. - Faecal sterols index limits has been established to a subtropical environment as way to ensure reliability for a more precise assessment of sewage contamination

Characterization of rain heights due to 0° isotherm in tropical and subtropical climates: implication on rain-induced attenuation prediction

Science.gov (United States)

Ojo, J. S.; Owolawi, P. A.

2018-01-01

In this paper, the dynamics of the structure of the rain profile as related to the zero-degree isotherm height and the implications for attenuation prediction along the Earth-space propagation links at locations in Nigeria, a tropical region, and South Africa, a subtropical region, are presented. Five-year (January 2010-December 2014) precipitation data on board the Tropical Rainfall Measuring Mission (TRMM) satellite have been analyzed over some selected locations in the two regions. The influences of the zero-degree isotherm height on some observed weather parameters are also discussed. The result on the influence of air temperature on rain height h r shows a significant increase in the tropical environment as compared with those in the subtropics. However, when h r results are compared with those obtained using rain height as recommended by the International Telecommunication Union (ITU), there is a significant difference at the 0.01% unavailability of the signal in a year particularly at higher frequencies. Further comparison with the slant path attenuation at 0.01% unavailability of the signal in a year shows a slight deviation (between 1.04 and 2.13 dB) in rain height than those acquired using the measured rain height in the tropical locations. Nevertheless, the result is slightly less than those obtained using the measured rain height in the subtropical locations with the differences in dB between - 0.49 and - 1.18. The overall results will be useful for estimating the link budgeting for digital radio satellite broadcasting. It will also be applicable for radar propagation systems at higher-frequency bands in Nigeria and South Africa.

Numerical simulation of cooling effect of vegetation enhancement in a subtropical urban park

International Nuclear Information System (INIS)

Yang, An-Shik; Juan, Yu-Hsuan; Wen, Chih-Yung; Chang, Chao-Jui

2017-01-01

Highlights: • The cooling efficacy from vegetation implanted in a urban public park is studied. • Three cases showing various types of greening in the park renewal were conducted. • On-site measurements were also conducted to validate the CFD simulation results. • The increase of GCR are linear with PET comfort area percentage. • Results can be used as a guideline for the green sustainability. - Abstract: Vegetation covers in urban parks are very useful for providing a cool microclimate which mitigates urban heat islands (UHIs). The objectives of this investigation are to therefore conduct on-site measurements and computational fluid dynamic simulations to evaluate the cooling efficacy from vegetation planted in a public park in Taipei, which is a subtropical city in Taiwan. The thermo-flow characteristics are predicted and compared with the measured air velocity and temperature data by using ultrasonic anemometers and an infrared camera to validate the computer modeling, including the sophisticated configurations of trees. Computations are also conducted to resolve the physiological equivalent temperature (PET) profiles for assessing the thermal comfort state at the pedestrian level of the outdoor environment. To investigate the impacts of park renewal on the urban microclimate, three pavilions and supplementary green areas are added to the simulation, and the results reveal that there is a better cooling effect in the park with a higher green coverage ratio (GCR). Moreover, the simulations find that the increased tree coverage ratio can more than compensate for loss of coverage of grasses, resulting in an overall decrease in average temperature. The relationship between thermal comfortable area and green coverage ratio tends to be nonlinear in nature. However, it would be more convenient for applications to adopt the linear regression analysis for determining the correlation between the GCR and PET for the percentage of areas that are comfortable (C

Nitrogen incorporation and retention by bacteria, algae, and fauna in a subtropical, intertidal sediment: An in situ 15N-labeling study

NARCIS (Netherlands)

Veuger, B.; Eyre, B.D.; Maher, D.; Middelburg, J.J.

2007-01-01

We performed a 15N-labeling study to investigate nitrogen incorporation and retention by the benthic microbial community (bacteria and benthic microalgae) and fauna in the intertidal sediment of the subtropical Australian Brunswick Estuary. The main experiment involved an in situ 15N pulse–chase

Correlação entre características quantitativas e qualitativas de frutos de pessegueiros na geração F2 cultivados em região subtropical Correlation between quantitative and qualitative characteristics of fruits of peach trees grown in subtropical conditions

Directory of Open Access Journals (Sweden)

Danielle Fabíola Pereira Silva

2013-02-01

Full Text Available O objetivo deste trabalho foi avaliar as relações entre características quantitativas e qualitativas de frutos de pessegueiro, cultivados em região subtropical. Para isso foram utilizados frutos totalmente maduros, obtidos de cinco populações, em geração F2, cultivadas em condições de clima subtropical. Foram avaliados: coloração da epiderme (coordenadas b* e h°, diâmetro médio do fruto, comprimento do fruto, firmeza instrumental da polpa, teor de sólidos solúveis, acidez titulável, teor de ácido ascórbico, percentagem de vermelho na epiderme, coloração da polpa, aderência do caroço, consistência manual da polpa e época de colheita. Os dados foram utilizados para obtenção de coeficientes parciais de correlação entre todas as variáveis. Observou-se variação entre os valores obtidos para cada característica. Há correlações parciais significativas a 1% de probabilidade, de intensidades médias e fracas, entre as características estudadas de frutos de pessegueiro. As maiores correlações foram obtidas entre comprimento e diâmetro de frutos (0,690** e entre os descritores b e h, obtidos por meio de colorímetro (0,516**. Frutos mais tardios apresentam, geralmente, maior firmeza de polpa, menores teores de vitamina C e menos pigmentação amarela na epiderme. Pêssegos de polpa amarela são mais firmes e apresentam maior acidez no suco.The objective this study was to evaluate the relationship between quantitative and qualitative characteristics of peach grown in subtropical regions. Fully ripe fruits obtained from five F2 populations grown in a subtropical climate were evaluated for: skin color (coordinates b* and h°, average fruit diameter, fruit length, pulp instrumental firmness, soluble solids, titratable acidity, ascorbic acid, percentage of red skin, flesh color , flesh adherence to pit, pulp consistency and harvest time. These data were used to obtain partial correlation coefficients of all variables

The Zoot Suit Riots: Exploring Social Issues in American History

Science.gov (United States)

Chiodo, John J.

2013-01-01

The Zoot Suit Riots provide students with a case study of social unrest in American history. The influx of Latinos into the Los Angeles area prior to World War II created high levels of social unrest between Mexican Americans, military servicemen, and local residences. With large numbers of soldiers stationed in the area during the Second World…

ENERGY BALANCE AND CO2 EXCHANGE BEHAVIOUR IN SUB-TROPICAL YOUNG PINE (Pinus roxburghii PLANTATION

Directory of Open Access Journals (Sweden)

B. K. Bhattacharya

2012-08-01

Full Text Available A study was conducted to understand the seasonal and annual energy balance behaviour of young and growing sub-tropical chir pine (Pinus roxburghii plantation of eight years age in the Doon valley, India and its coupling with CO2 exchange. The seasonal cycle of dekadal daytime latent heat fluxes mostly followed net radiation cycle with two minima and range between 50–200 Wm-2 but differed from the latter during the period when soil wetness and cloudiness were not coupled. Dekadal evaporative fraction closely followed the seasonal dryness-wetness cycle thus minimizing the effect of wind on energy partitioning as compared to diurnal variation. Daytime latent heat fluxes were found to have linear relationship with canopy net assimilation rate (Y = 0.023X + 0.171, R2 = 0.80 though nonlinearity exists between canopy latent heat flux and hourly net CO2 assimilation rate . Night-time plant respiration was found to have linear relationship (Y = 0.088 + 1.736, R2 = 0.72 with night-time average vapour pressure deficit (VPD. Daily average soil respiration was found to be non-linearly correlated to average soil temperatures (Y = -0.034X2 + 1.676X – 5.382, R2 = 0.63 The coupled use of empirical models, seasonal energy fluxes and associated parameters would be useful to annual water and carbon accounting in subtropical pine ecosystem of India in the absence high-response eddy covariance tower.

Distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, as compared with those of the eastern Chinese subtropical regions

Directory of Open Access Journals (Sweden)

Tang, C. Q.

2015-12-01

Full Text Available This paper analyzes the geographic distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, and compares with other subtropical regions in the east of China in terms of forest types, pertinent species, and spatial distribution along latitudinal, longitudinal and altitudinal gradients. In general, for both the western and the eastern subtropical regions, the evergreen broad-leaved forests are dominated by species of Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia, and Michelia, (Magnoliaceae, while in southwestern China there are more diverse forest types including semi-humid, monsoon, mid-montane moist and humid evergreen broad-leaved forests, but only monsoon and humid forests in the east. The Yunnan area has more varied species of Lithocarpus or Cyclobalanopsis or Castanopsis as dominants than does eastern China, where the chief dominant genus is Castanopsis. The upper limits of the evergreen broad-leaved forests are mainly 2400–2800 m in western Yunnan and western Sichuan, much higher than in eastern China (600–1500, but 2500 m in Taiwan. Also discussed are the environmental effects on plant diversity of the evergreen broad-leaved forest ecosystems exemplified by Yunnan and Taiwan.En este trabajo se analiza los patrones de distribución geográfica de los bosques subtropicales perennifolios de hoja ancha del suroeste de china, y se comparan con los de otras regiones subtropicales del este de China en términos de tipología de bosque, especies relevantes, y distribución espacial a lo largo de un gradiente latitudinal, longitudinal y altitudinal. De manera general, los bosques perennifolios de hoja ancha de la regiones subtropicales tanto orientales como occidentales presentan dominancia de especies de Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia y Michelia

Characterizing spatial and temporal variability in methane gas-flux dynamics of subtropical wetlands in the Big Cypress National Preserve, Florida

Science.gov (United States)

Sirianni, M.; Comas, X.; Shoemaker, B.

2017-12-01

Wetland methane emissions are highly variable both in space and time, and are controlled by changes in certain biogeochemical controls (i.e. organic matter availability; redox potential) and/or other environmental factors (i.e. soil temperature; water level). Consequently, hot spots (areas with disproportionally high emissions) may develop where biogeochemical and environmental conditions are especially conducive for enhancing certain microbial processes such as methanogenesis. The Big Cypress National Preserve is a collection of subtropical wetlands in southwestern Florida, including extensive forested (cypress, pine, hardwood) and sawgrass ecosystems that dry and flood annually in response to rainfall. In addition to rainfall, hydroperiod, fire regime, elevation above mean sea level, dominant vegetation type and underlying geological controls contribute to the development and evolution of organic and calcitic soils found throughout the Preserve. Currently, the U.S. Geological Survey employs eddy covariance methods within the Preserve to quantify carbon and methane exchanges over several spatially extensive vegetation communities. While eddy covariance towers are a convenient tool for measuring gas exchanges at the ecosystem scale, their spatially extensive footprint (hundreds of meters) may mask smaller scale spatial variabilities that may be conducive to the development of hot spots. Similarly, temporal resolution (i.e. sampling effort) at scales smaller that the eddy covariance measurement footprint is important since low resolution data may overlook rapid emission events and the temporal variability of discrete hot spots. In this work, we intend to estimate small-scale contributions of organic and calcitic soils to gas exchanges measured by the eddy covariance towers using a unique combination of ground penetrating radar (GPR), capacitance probes, gas traps, and time-lapse photography. By using an array of methods that vary in spatio-temporal resolution, we

New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir

Science.gov (United States)

Wells, Ray E.; Haugerud, Ralph A.; Niem, Alan; Niem, Wendy; Ma, Lina; Madin, Ian; Evarts, Russell C.

2018-04-10

A geologic map of the greater Portland, Oregon, metropolitan area is planned that will document the region’s complex geology (currently in review: “Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington,” by Wells, R.E., Haugerud, R.A., Niem, A., Niem, W., Ma, L., Evarts, R., Madin, I., and others). The map, which is planned to be published as a U.S. Geological Survey Scientific Investigations Map, will consist of 51 7.5′ quadrangles covering more than 2,500 square miles, and it will represent more than 100 person-years of geologic mapping and studies. The region was mapped at the relatively detailed scale of 1:24,000 to improve understanding of its geology and its earthquake hazards. More than 100 geologic map units will record the 50-million-year history of volcanism, sedimentation, folding, and faulting above the Cascadia Subduction Zone. The geology contributes to the varied terroir of four American Viticultural Areas (AVAs) in the northwestern Willamette Valley: the Yamhill-Carlton, Dundee Hills, Chehalem Mountains, and Ribbon Ridge AVAs. Terroir is defined as the environmental conditions, especially climate and soils, that influence the quality and character of a region’s crops—in this case, grapes for wine.On this new poster (“New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir”), we present the geologic map at a reduced scale (about 1:175,000) to show the general distribution of geologic map units, and we highlight, discuss, and illustrate six major geologic events that helped shape the region and form its terrior. We also discuss the geologic elements that contribute to the character of each of the four AVAs in the northwestern Willamette Valley.

Transfer of 137Cs from soil to plants in a wet montane forest in subtropical Taiwan

International Nuclear Information System (INIS)

Chih-Yu Chiu

1999-01-01

The distribution of 137 Cs in an undisturbed, multistoried, subtropical wet montane forest ecosystem surrounding Yuanyang Lake (lake surface level ca. 1670 m, in northeastern Taiwan), was investigated. The mossy forest here represents a currently-rare perhumid temperate environment in subtropical region. The radioactivity concentration of 137 Cs was determined by γ-spectroscopy with a Ge(Li) detector. Although the soil is extremely acidic (pH 3.3 to 3.6) and the rainfall is high, 137 Cs is evidently retained in the organic layer. The radioactivity concentration of 137 Cs in surface soil ranges from 28 to 71 Bq x kg -1 . The concentrations of 137 Cs in the ground moss layer and litter were much lower than that in the soil organic layer; this suggests that 137 Cs detected is not from the newly deposited radioactive fallout. The radioactivity concentration and transfer factor (TF) of 137 Cs varied with plant species. Shrubs and ferns have higher values than a coniferous tree (Taiwan cedar). The TF in this ecosystem is as high as 0.21 to 1.88. The high values of TF is attributed to the abundance of the organic matter in the forest soils. The rapid recycling of 137 Cs through the soil-plant system of this undisturbed multistoried ecosystem suggests the existence of an internal cycling that help the accumulation of 137 Cs in this ecosystem. (author)

Anthropogenic effects on the subtropical jet in the Southern Hemisphere: aerosols versus long-lived greenhouse gases

International Nuclear Information System (INIS)

Rotstayn, L D; Collier, M A; Jeffrey, S J; Syktus, J I; Wong, K K; Kidston, J

2013-01-01

We use single-forcing historical simulations with a coupled atmosphere–ocean global climate model to compare the effects of anthropogenic aerosols (AAs) and increasing long-lived greenhouse gases (LLGHGs) on simulated winter circulation in the Southern Hemisphere (SH). Our primary focus is on the subtropical jet, which is an important source of baroclinic instability, especially in the Australasian region, where the speed of the jet is largest. For the period 1950 to 2005, our simulations suggest that AAs weaken the jet, whereas increasing LLGHGs strengthen the jet. The different responses are explained in terms of thermal wind balance: increasing LLGHGs preferentially warm the tropical mid-troposphere and upper troposphere, whereas AAs have a similar effect of opposite sign. In the mid-troposphere, the warming (cooling) effect of LLGHGs (AAs) is maximal between 20S and 30S; this coincides with the descending branch of the Hadley circulation, which may advect temperature changes from the tropical upper troposphere to the subtropics of the SH. It follows that LLGHGs (AAs) increase (decrease) the mid-tropospheric temperature gradient between low latitudes and the SH mid-latitudes. The strongest effects are seen at longitudes where the southward branches of the Hadley cell in the upper troposphere are strongest, notably at those that correspond to Asia and the western Pacific warm pool. (letter)

Analysis of the Relationship Between Physical Environmental Parameters and Beach Water Quality in a Subtropical Setting

Science.gov (United States)

Zhu, X.; Wang, J. D.; Elmir, S.; Solo-Gabriele, H. M.; Wright, M. E.; Abdelzaher, A.

2006-12-01

Fecal Indicator Bacteria(FIB) are found in high concentrations in sewage water, and thus are used to indicate whether there is fecal material related pathogen present and to determine whether a beach is safe for recreational use. Studies have shown, however, in subtropical regions, FIB concentrations above EPA standards may be present in the absence of known point sources of human or animal waste, thus reducing the efficacy of FIB beach monitoring programs. An interdisciplinary study is being conducted in Miami, Florida , the goal is to understand the sources and behavior of FIB on a beach without point source loads and also to improve beach health hazard warnings in subtropical regions. This study, examines relationship between enterococci (EPA recommended FIB for use in marine water) and physical environmental parameters such as rain, tide and wind. FIB data employed include Florida Department of Health weekly beach monitoring enterococci (ENT) data during a five year period and a two-day experiment with hourly sampling at Hobie Cat Beach on Virginia Key in the Miami metropolitan area. The environmental data consist of wind from a nearby CMAN tower, and local rain and tide. The analysis also includes data from nearby beaches monitored by the Health Department. Results show the correlation coefficient between ENT and tide at Hobie Cat Beach is positive but not significant(r=0.17). Rain events have a significant influence on ENT at Hobie Cat Beach, with a correlation coefficient of up to 0.7 while at other beaches the correlation is less than 0.2. Reasons for this aberration are being investigated. Although this is the only beach allowing dogs there are other factors of possible importance, such as tidal flats frequented by birds and weaker water circulation and exchange at this beach facing a bay rather than the ocean. Higher ENT levels (> 300CFU/100ml water) are more likely (67% of the time) to be associated with periods of onshore winds, which may affect the

White-faced storm-petrels Pelagodroma marina predated by gulls as biological monitors of plastic pollution in the pelagic subtropical Northeast Atlantic.

Science.gov (United States)

Furtado, Ricardo; Menezes, Dilia; Santos, Carolina Jardim; Catry, Paulo

2016-11-15

Marine plastic pollution is rapidly growing and is a source of major concern. Seabirds often ingest plastic debris and are increasingly used as biological monitors of plastic pollution. However, virtually no studies have assessed plastics in seabirds in the deep subtropical North Atlantic. We investigated whether remains of white-faced storm-petrels (WFSP) present in gull pellets could be used for biomonitoring. We analysed 263 pellets and 79.0% of these contained plastic debris originating in the digestive tract of WFSP. Pellets with no bird prey did not contain plastics. Most debris were fragments (83.6%) with fewer plastic pellets (8.2%). Light-coloured plastics predominated (71.0%) and the most frequent polymer was HDPE (73.0%). Stable isotopes in toe-nails of WFSP containing many versus no plastics did not differ, indicating no individual specialisation leading to differential plastic ingestion. We suggest WFSP in pellets are highly suitable to monitor the little known pelagic subtropical Northeast Atlantic. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Latin American Moessbauer research community

International Nuclear Information System (INIS)

Stevens, J.G.

1994-01-01

Interest in Moessbauer spectroscopy among the Latin American countries has increased in the last five years. Two-thirds of the published research is coming from the Moessbauer research groups in Brazil. Other Latin American countries with active Moessbauer research include Argentina, Chile, Columbia, Cuba, Mexico, Peru, and Venezuela. In recent years, the area having the most interest has been the investigation of minerals and high temperature superconductors. (orig.)

Bryophyte-dominated biological soil crusts mitigate soil erosion in an early successional Chinese subtropical forest

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S. Seitz

2017-12-01

Full Text Available This study investigated the development of biological soil crusts (biocrusts in an early successional subtropical forest plantation and their impact on soil erosion. Within a biodiversity and ecosystem functioning experiment in southeast China (biodiversity and ecosystem functioning (BEF China, the effect of these biocrusts on sediment delivery and runoff was assessed within micro-scale runoff plots under natural rainfall, and biocrust cover was surveyed over a 5-year period. Results showed that biocrusts occurred widely in the experimental forest ecosystem and developed from initial light cyanobacteria- and algae-dominated crusts to later-stage bryophyte-dominated crusts within only 3 years. Biocrust cover was still increasing after 6 years of tree growth. Within later-stage crusts, 25 bryophyte species were determined. Surrounding vegetation cover and terrain attributes significantly influenced the development of biocrusts. Besides high crown cover and leaf area index, the development of biocrusts was favoured by low slope gradients, slope orientations towards the incident sunlight and the altitude of the research plots. Measurements showed that bryophyte-dominated biocrusts strongly decreased soil erosion, being more effective than abiotic soil surface cover. Hence, their significant role in mitigating sediment delivery and runoff generation in mesic forest environments and their ability to quickly colonise soil surfaces after disturbance are of particular interest for soil erosion control in early-stage forest plantations.

Bryophyte-dominated biological soil crusts mitigate soil erosion in an early successional Chinese subtropical forest

Science.gov (United States)

Seitz, Steffen; Nebel, Martin; Goebes, Philipp; Käppeler, Kathrin; Schmidt, Karsten; Shi, Xuezheng; Song, Zhengshan; Webber, Carla L.; Weber, Bettina; Scholten, Thomas

2017-12-01

This study investigated the development of biological soil crusts (biocrusts) in an early successional subtropical forest plantation and their impact on soil erosion. Within a biodiversity and ecosystem functioning experiment in southeast China (biodiversity and ecosystem functioning (BEF) China), the effect of these biocrusts on sediment delivery and runoff was assessed within micro-scale runoff plots under natural rainfall, and biocrust cover was surveyed over a 5-year period. Results showed that biocrusts occurred widely in the experimental forest ecosystem and developed from initial light cyanobacteria- and algae-dominated crusts to later-stage bryophyte-dominated crusts within only 3 years. Biocrust cover was still increasing after 6 years of tree growth. Within later-stage crusts, 25 bryophyte species were determined. Surrounding vegetation cover and terrain attributes significantly influenced the development of biocrusts. Besides high crown cover and leaf area index, the development of biocrusts was favoured by low slope gradients, slope orientations towards the incident sunlight and the altitude of the research plots. Measurements showed that bryophyte-dominated biocrusts strongly decreased soil erosion, being more effective than abiotic soil surface cover. Hence, their significant role in mitigating sediment delivery and runoff generation in mesic forest environments and their ability to quickly colonise soil surfaces after disturbance are of particular interest for soil erosion control in early-stage forest plantations.

Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest.

Science.gov (United States)

Jin, Yi; Qian, Hong; Yu, Mingjian

2015-01-01

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as βNRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.

Investigating effect of environmental controls on dynamics of CO2 budget in a subtropical estuarial marsh wetland ecosystem

Science.gov (United States)

Lee, Sung-Ching; Fan, Chao-Jung; Wu, Zih-Yi; Juang, Jehn-Yih

2015-02-01

In this study, we quantified the ecosystem-scale CO2 exchange of two different but typical low-latitude vegetation types, para grass and reed, in a subtropical wetland ecosystem by integrating flux observation with the parameterization of environmental variables. In addition, we explored how seasonal dynamics of environmental factors affected variations in CO2 budget. The results suggest that gross primary production (GPP, in the order of 1700 gC m-2 yr-1) of CO2 was higher in this site than in previous studies of northern peatlands and estuarial wetlands because of the direct effect of environmental factors. Temperature and radiation had a larger effect than water status (soil moisture content and vapor pressure deficit) on GPP for the two low-latitude ecosystems, which differ from the results for high-latitude regions. Environmental variables had a strong but different impact on the CO2 budget for para grass and reed areas. This diversity led to different potential shifts and trends of biomass accumulation and distribution of these two typical low-latitude vegetation types under different scenarios of environmental change. The findings from this study can sufficiently provide quantitative understanding of CO2 budgets in low-latitude wetlands.

[Blood feeding preference of Lutzomyia whitmani (Diptera, Psychodidae) in a transmission area for American cutaneous leishmaniasis in the State of Maranhão, Brazil].

Science.gov (United States)

Fonteles, Raquel Silva; Vasconcelos, Gabriel Costa E; Azevêdo, Patrícia Castelo Branco; Lopes, Gildevan Nolasco; Moraes, Jorge Luiz Pinto; Lorosa, Elias Seixas; Kuppinger, Oliver; Rebêlo, José Manuel Macário

2009-01-01

The aim of this study was to determine the sources of blood meals for females of Lutzomyia whitmani, a phlebotomine species incriminated as the main vector for American cutaneous leishmaniasis in Maranhão. For this, 70 Lutzomyia whitmani females were collected in the municipality of Axixá, an area with one of the greatest numbers of cases of American cutaneous leishmaniasis in humans in Maranhão. They were analyzed using the precipitin technique. Ninety percent of the specimens showed a reaction to some type of antiserum positive immune reaction, among which 73% presented single reactions, with predominance for chicken blood (22%), rodent blood (14.3%) and human blood (12.7%). Among the double reactions, the predominant combinations were chicken/human (6.3%), chicken/opossum (4.8%), ox/human (3.2%) and opossum/human (3.2%). Thus, we conclude that humans and domestic and synanthropic animals are blood meal sources for Lutzomyia whitmani and may play an important role in the transmission cycle for American cutaneous leishmaniasis, thus explaining the cases of this disease in Axixá.

Biodiversity of frog haemoparasites from sub-tropical northern KwaZulu-Natal, South Africa

Science.gov (United States)

Netherlands, Edward C.; Cook, Courtney A.; Kruger, Donnavan J.D.; du Preez, Louis H.; Smit, Nico J.

2015-01-01

Since South Africa boasts a high biodiversity of frog species, a multispecies haemoparasite survey was conducted by screening the blood from 29 species and 436 individual frogs. Frogs were collected at three localities in sub-tropical KwaZulu-Natal, a hotspot for frog diversity. Twenty per cent of the frogs were infected with at least one of five groups of parasites recorded. Intraerythrocytic parasites comprising Hepatozoon, Dactylosoma, and viral or bacterial organisms, as well as extracellular parasites including trypanosomes and microfilarid nematodes were found. A significant difference (P Hepatozoon and Trypanosoma species accounted for most of the infections, the former demonstrating significant differences in intensity of infection across species, families and habitat types (P = 0.028; P = 0.006; P = 0.007 respectively). Per locality, the first, the formally protected Ndumo Game Reserve, had the highest biodiversity of haemoparasite infections, with all five groups of parasites recorded. The other two sites, that is the area bordering the reserve and the Kwa Nyamazane Conservancy, had a lower diversity with no parasite infections recorded and only Hepatozoon species recorded respectively. Such findings could be ascribed to the anthropogenic impact on the latter two sites, the first by the rural village activities, and the second by the bordering commercial sugar cane agriculture. Future studies should include both morphological and molecular descriptions of the above parasites, as well as the identification of potential vectors, possibly clarifying the effects human activities may have on frog haemoparasite life cycles and as such their biodiversity. PMID:25830113

Cutaneous larva migrans in northern climates. A souvenir of your dream vacation.

Science.gov (United States)

Edelglass, J W; Douglass, M C; Stiefler, R; Tessler, M

1982-09-01

Three young women recently returned to the metropolitan Detroit area with cutaneous larva migrans. All three had vacationed at a popular club resort on the Caribbean island of Martinique. Cutaneous larva migrans is frequently seen in the southern United States, Central and South America, and other subtropical areas but rarely in northern climates. Several organisms can cause cutaneous larva migrans, or creeping eruption. The larvae of the nematode Ancylostoma braziliense are most often the causative organisms. Travel habits of Americans make it necessary for practitioners in northern climates to be familiar with diseases contracted primarily in warmer locations. The life cycle of causative organisms and current therapy are reviewed.

Unsynchronized influenza epidemics in two neighboring subtropical cities

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Xiujuan Tang

2018-04-01

Full Text Available Objective: The aim of this study was to examine the synchrony of influenza epidemics between Hong Kong and Shenzhen, two neighboring subtropical cities in South China. Methods: Laboratory-confirmed influenza data for the period January 2006 to December 2016 were obtained from the Shenzhen Center for Disease Control and Prevention and the Department of Health in Hong Kong. The population data were retrieved from the 2011 population censuses. The weekly rates of laboratory-confirmed influenza cases were compared between Shenzhen and Hong Kong. Results: Unsynchronized influenza epidemics between Hong Kong and Shenzhen were frequently observed during the study period. Influenza A/H1N1 caused a more severe pandemic in Hong Kong in 2009, but the subsequent seasonal epidemics showed similar magnitudes in both cities. Two influenza A/H3N2 dominant epidemic waves were seen in Hong Kong in 2015, but these epidemics were very minor in Shenzhen. More influenza B epidemics occurred in Shenzhen than in Hong Kong. Conclusions: Influenza epidemics appeared to be unsynchronized between Hong Kong and Shenzhen most of the time. Given the close geographical locations of these two cities, this could be due to the strikingly different age structures of their populations. Keywords: Influenza epidemics, Synchrony, Shenzhen, Hong Kong

Tolerance to High Temperature Extremes in an Invasive Lace Bug, Corythucha ciliata (Hemiptera: Tingidae), in Subtropical China

OpenAIRE

Ju, Rui-Ting; Gao, Lei; Zhou, Xu-Hui; Li, Bo

2013-01-01

Biological invasions are predicted to be more frequent as climate change is increasing its positive impact on the prevalence of invasive exotic species. Success of insect invaders in different temperature zones is closely related to their tolerance to temperature extremes. In this study, we used an exotic lace bug (Corythucha ciliata) as the study organism to address the hypotheses that an insect species invading a subtropical zone from temperate regions has a high capacity to survive and ada...

Toxocariosis en niños de una región subtropical

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María de los Ángeles López

2005-06-01

Full Text Available La toxocariosis está presente en todo el mundo, pero se considera en mayor riesgo a los habitantes de zonas con deficiencias sanitarias y particularmente a los niños. El objetivo de este trabajo fue conocer aspectos inmunológicos y clínicos de la infección infantil en un área subtropical de Argentina, para lo cual se estudiaron 182 niños de ambos sexos de la ciudad de Resistencia (Noreste de Argentina, de 0 a 16 años, con eosinofilia mayor al 10%. Se realizaron exámenes clínicos, encuestas epidemiológicas, exámenes copropa-rasitológicos y dosajes de IgG e IgM anti Toxocara canis por EIE; los sueros positivos fueron confirmados por Western Blot. De los 182 niños estudiados, 122 resultaron seropositivos (67%, 28.8% no contaban con agua potable en su domicilio, 58.8% no tenían cloacas, 91.1% habían tenido contacto con perros y/o gatos, 30.0% tenían antecedentes de geofagia y 86.7% vivían sobre calles sin pavimento. La infección se presentó en forma asintomática en el 77.8% de los casos, como larva migrans ocular en el 6.7% y como larva migrans visceral en el 15.5 % de los casos. En 22 niños el seguimiento serológico post-tratamiento hasta los 18 meses mostró que la IgG se mantuvo estable en 10 casos, en 11 disminuyó pero manteniendo valores elevados y en uno aumentó. Hubo 19 casos con IgM positiva; 8 disminuyeron sus títulos, uno se mantuvo estable y 10 se negativizaron. Hubo un caso de reinfección. Estos resultados reafirman la importancia que las autoridades sanitarias deben asignar a esta infección, particularmente en las regiones carenciadas, en las que habitualmente no se reconoce a la toxocariosis como un problema relevante de salud pública.Toxocariasis in children from a subtropical region

Performance assessment of earth pipe cooling system for low energy buildings in a subtropical climate

International Nuclear Information System (INIS)

Ahmed, S.F.; Khan, M.M.K.; Amanullah, M.T.O.; Rasul, M.G.; Hassan, N.M.S.

2015-01-01

Highlights: • Earth pipe cooling performance was investigated in a subtropical climate in Australia. • A thermal model was developed using Fluent to assess the cooling performance. • A temperature reduction of around 2 °C was found for the earth pipe cooling system. • Annual energy savings of maximum 866.54 kW (8.82%) was achieved for a 27.23 m"3 room. - Abstract: Energy consumption in heating and cooling around the world has been a major contributor to global warming. Hence, many studies have been aimed at finding new techniques to save and control energy through energy efficient measures. Most of this energy is used in residential, agricultural and commercial buildings. It is therefore important to adopt energy efficiency measures in these buildings through new technologies and novel building designs. These new building designs can be developed by employing various passive cooling systems. Earth pipe cooling is one of these which can assist to save energy without using any customary mechanical units. This paper investigates the earth pipe cooling performance in a hot humid subtropical climate of Rockhampton, Australia. A thermal model is developed using ANSYS Fluent for measuring its performance. Impacts of air velocity, air temperature, relative humidity and soil temperature on room cooling performance are also assessed. A temperature reduction of around 2 °C was found for the system. This temperature reduction contributed to an energy saving of a maximum of 866.54 kW (8.82%) per year for a 27.23 m"3 room.

Carbon stocks assessment in subtropical forest types of Kashmir Himalayas

International Nuclear Information System (INIS)

Shaheen, H.; Khan, R.W.A.; Hussain, K.; Ullah, T.S.; Mehmood, A.

2016-01-01

Estimation of carbon sequestration in forest ecosystem is necessary to mitigate impacts of climate change. Current research project was focused to assess the Carbon contents in standing trees and soil of different subtropical forest sites in Kashmir. Tree biomass was estimated by using allometric equations whereas Soil carbon was calculated by Walkey-Black titration method. Total carbon stock was computed as 186.27 t/ha with highest value of 326 t/ha recorded from Pinus roxburghii forest whereas lowest of 75.86 t/ha at mixed forest. Average biomass carbon was found to be 151.38 t/ha with a maximum value of 294.7 t/ha and minimum of 43.4 t/ha. Pinus roxburghii was the most significant species having biomass value of 191.8 t/ha, followed by Olea cuspidata (68.9 t/ha), Acacia modesta (12.71 t/ha), Dalbergia sissoo (12.01 t/ha), Broussonetia papyrifera (5.93 t/ha), Punica granatum (2.27 t/ha), Mallotus philippensis (2.2 t/ha), Albizia lebbeck (1.8t/ha), Ficus palmata (1.51 t/ha), Acacia arabica (1.4 t/ha), Melia azedarach, (1.14 t/ha) and Ficus carica (1.07 t/ha) respectively. Recorded value of tree density was 492/ha; average DBH was 87.27 cm; tree height was 13.3m; and regeneration value was 83 seedlings/ha. Soil carbon stocks were found to be 34.89 t/ha whereas agricultural soil carbon was calculated as 27.18 t/ha. Intense deforestation was represented by a stump density of 147.4/ha. The results of Principal Component Analysis (PCA) revealed the distinct species clusters on the basis of location, biomass and Carbon stock values. Pinus roxburghii and Olea cuspidata were found to be the major contributors of carbon stock having maximum vector lengths in the PCA Biplot. Forest in the area needs to be managed in a sustainable manner to increase its carbon sequestration potential. (author)

Impacts of increasing typhoons on the structure and function of a subtropical forest: reflections of a changing climate.

Science.gov (United States)

Lin, Kuo-Chuan; Hamburg, Steven P; Wang, Lixin; Duh, Chin-Tzer; Huang, Chu-Mei; Chang, Chung-Te; Lin, Teng-Chiu

2017-07-07

Due to their destructive and sporadic nature, it is often difficult to evaluate and predict the effects of typhoon on forest ecosystem patterns and processes. We used a 21-yr record of litterfall rates to explore the influence of typhoon frequency and intensity, along with other meteorological variables, on ecosystem dynamics in a subtropical rainforest. Over the past half century there has been an increasing frequency of strong typhoons (category 3; >49.6 m s -1 ; increase of 1.5 typhoons/decade) impacting the Fushan Experimental Forest, Taiwan. At Fushan strong typhoons drive total litterfall mass with an average of 1100 kg ha -1 litterfall typhoon -1 . While mean typhoon season litterfall has been observed to vary by an order of magnitude, mean litterfall rates associated with annual leaf senescence vary by typhoon frequency, total annual litter mass increased gradually over the 21-year record following three major typhoons in 1994. Monthly maximum wind speed was predictive of monthly litterfall, yet the influence of precipitation and temperature was only evident in non-typhoon affected months. The response of this subtropical forest to strong typhoons suggests that increasing typhoon frequency has already shifted ecosystem structure and function (declining carbon sequestration and forest stature).

Oviposition activity and seasonal pattern of a population of Aedes (Stegomyia aegypti (L. (Diptera: Culicidae in subtropical Argentina

Directory of Open Access Journals (Sweden)

Micieli María Victoria

2003-01-01

Full Text Available Monthly oviposition activity and the seasonal density pattern of Aedes aegypti were studied using larvitraps and ovitraps during a research carried out by the Public Health Ministry of Salta Province, in Tartagal, Aguaray and Salvador Mazza cities, in subtropical Argentina. The A. aegypti population was active in both dry and wet seasons with a peak in March, accordant with the heaviest rainfall. From May to November, the immature population level remained low, but increased in December. Ae. aegypti oviposition activity increased during the fall and summer, when the relative humidity was 60% or higher. Eggs were found in large numbers of ovitraps during all seasons but few eggs were observed in each one during winter. The occurrence and the number of eggs laid were variable when both seasons and cities were compared. The reduction of the population during the winter months was related to the low in the relative humidity of the atmosphere. Significant differences were detected between oviposition occurrences in Tartagal and Aguaray and Salvador Mazza cities, but no differences in the number of eggs were observed. Two factors characterize the seasonal distribution pattern of Ae. aegypti in subtropical Argentina, the absence of a break during winter and an oviposition activity concomitant of the high relative humidity of the atmosphere.

Organizational Religious Behavior among Older African Americans: Findings from the National Survey of American Life.

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Taylor, Robert Joseph; Chatters, Linda M; Bullard, Kai McKeever; Wallace, John M; Jackson, James S

2009-07-01

This study utilizes data from the older African American sub-sample of the National Survey of American Life (n=837) to examine the sociodemographic and denominational correlates of organizational religious involvement among older African Americans. Six measures of organizational religious participation are utilized, including two measures of time allocation for organized religious pursuits. The findings indicate significant gender, region, marital status and denominational differences in organizational religiosity. Of particular note, although older black women generally displayed higher levels of religious participation, older black men spent more hours per week in other activities at their place of worship. The findings are discussed in relation to prior work in the area of religious involvement among older adults. New directions for research on religious time allocation are outlined.

Detecting the progression of ocean acidification from the saturation state of CaCO3 in the subtropical South Pacific

Science.gov (United States)

Murata, Akihiko; Hayashi, Kazuhiko; Kumamoto, Yuichiro; Sasaki, Ken-ichi

2015-04-01

Progression of ocean acidification in the subtropical South Pacific was investigated by using high-quality data from trans-Pacific zonal section at 17°S (World Ocean Circulation Experiment section P21) collected in 1994 and 2009. During this 15 year period, the CaCO3 saturation state of seawater with respect to calcite (Ωcal) and aragonite (Ωarg) in the upper water column (Pacific Ocean.

Impacts of disturbance initiated by road construction in a subtropical cloud forest in the Luquillo Experimental Forest, Puerto Rico

Science.gov (United States)

Lydia P. Olander; F.N Scatena; Whendee L. Silver

1998-01-01

The impacts of road construction and the spread of exotic vegetation, which are common threats to upper elevation tropical forests, were evaluated in the subtropical cloud forests of Puerto Rico. The vegetation, soil and microclimate of 6-month-old road®lls, 35-year-old road®lls and mature forest with and without grass understories were compared. Recent road®lls had...

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Institute of Scientific and Technical Information of China (English)

HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

2012-01-01

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

Three Generations of Greek Americans: A Study in Ethnicity.

Science.gov (United States)

Scourby, Alice

1980-01-01

Measures ethnic identity among three generations of Greek Americans living in the New York Metropolitan area. Shows that, though there is a generational variation, the majority of Greeks still have relatively strong attachment to their ethnic culture, despite their identification with American society. (Author/GC)

Cesium and strontium sorption by selected tropical and subtropical soils around nuclear facilities

International Nuclear Information System (INIS)

Chiang, P.N.; Wang, M. K.; Huang, P.M.; Wang, J.J.; Chiu, C.Y.

2010-01-01

The dynamics of Cs and Sr sorption by soils, especially in the subtropics and tropics, as influenced by soil components are not fully understood. The rates and capacities of Cs and Sr sorption by selected subtropical and tropical soils in Taiwan were investigated to facilitate our understanding of the transformation and dynamics of Cs and Sr in soils developed under highly weathering intensity. The Langmuir isotherms and kinetic rates of Cs and Sr sorption on the Ap1 and Bt1 horizons of the Long-Tan (Lt) and the A and Bt1 horizons of the Kuan-Shan (Kt), Mao-Lin (Tml) and Chi-Lo (Cl) soils were selected for this study. Air-dried soil ( -5 to 1.88 x 10 -3 M of CsCl (pH 4.0) or 1.14 x 10 -4 to 2.85 x 10 -3 M of SrCl 2 (pH 4.0) solutions at 25 deg. C. The sorption maximum capacity (q m ) of Cs by the Ap1 and Bt1 horizons of the Lt soil (62.24 and 70.70 mmol Cs kg -1 soil) were significantly (p -1 soil in Kt soil and 34.83 and 29.96 mmol Cs kg -1 soil in Cl soil, respectively), however, the sorption maximum capacity values of the Lt and Tml soils did not show significant differences. The amounts of pyrophosphate extractable Fe (Fe p ) were correlated significantly with the Cs and Sr sorption capacities (for Cs sorption, r 2 = 0.97, p -4 ; for Sr sorption, r 2 = 0.82, p -3 ). The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil >> Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data. The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. This is attributable to the availability of more energy for bond breaking and bond formation brought about by the higher temperatures. The rate constant of Cs sorption at 308 K was 1.39-2.09 times higher than that at 278 K in the four soils. The activation energy of Cs and Sr sorbed by the four soils ranged from 7.2 to 16.7 kJ mol -1 and from 15.2 to 22.4 kJ mol

Literature review and ethnohistory of Native American occupancy and use of the Yucca Mountain Region

International Nuclear Information System (INIS)

Stoffle, R.W.; Olmsted, J.E.; Evans, M.J.

1990-01-01

This report presents a review of the literature concerning Native American occupancy and use of the Yucca Mountain area and vicinity. It draws on a wide range of material, including early traveler reports, government documents, ethnographic and historical works, and local newspapers. The report complements two other concurrent studies, one focused on the cultural resources of Native American people in the study area and the other an ethnobotanical study of plant resources used by Native American people in the study area. The literature review has had two principal purposes: to determine the completeness of the Yucca Mountain Native American study design and to contribute to the understanding of the presence of Native American people in the Yucca Mountain area. A review of the existing literature about the Yucca Mountain area and southern Nye County, supplemented by the broader literature about the Great Basin, has verified three aspects of the study design. First, the review has aided in assessing the completeness of the list of Native American ethnic groups that have traditional or historical ties to the site. Second, it has aided in the production of a chronology of Native American activities that occurred on or near the site during the late nineteenth and early twentieth centuries. Third, it has helped to identify the location of cultural resources, including burials and other archaeological sites, in the study area and vicinity. 200 refs., 16 figs., 6 tabs

Seasonal and environmental influences on recruitment patterns and habitat usage among resident and transient fishes in a World Heritage Site subtropical estuary.

Science.gov (United States)

Pichler, H A; Gray, C A; Broadhurst, M K; Spach, H L; Nagelkerken, I

2017-01-01

This study investigated whether the fish communities inhabiting shallow non-vegetated habitats in two divergent bays in a subtropical World Heritage Site estuarine system differed according to wet (spring-summer) and dry (autumn-winter) seasons or polyhaline and mesohaline zones, within the broader objective of facilitating spatio-temporal management. Species richness (total of 74 taxa; total length, L T  = 11-552 mm) and abundance (51 109 individuals) were mostly greater in the wet than dry season and in polyhaline than mesohaline areas. There was a major effect of rainfall on recruitment, particularly among transient fishes, which could be the result of enhanced survival of young via greater productivity (food resources) and protection from predators (via turbidity reducing visual cues). Salinity had strong interactive effects with rainfall and temperature in one bay, with greater species richness and overall abundances as well as large abundances of four key species [Anchoa januaria and Atherinella brasiliensis (pelagic residents), Cetengraulis edentulus (pelagic transient) and Diapterus rhombeus (demersal transient)] during the wet season in polyhaline areas; possibly reflecting a biodiversity hotspot that might be affected by distance to the estuary mouth and convergence hydrology. Regionally, the results support enforcing spatio-temporal restrictions to minimize anthropogenic activities within statutory (but not always enforced) protected areas. Globally, the data reiterate the need to identify and understand biotic and abiotic effects on estuarine ichthyofaunal distributions and abundances as a precursor to their management. © 2016 The Fisheries Society of the British Isles.

Assessment of atmospheric processes driving ozone variations in the subtropical North Atlantic free troposphere

Directory of Open Access Journals (Sweden)

E. Cuevas

2013-02-01

Full Text Available An analysis of the 22-yr ozone (O₃ series (1988–2009 at the subtropical high mountain Izaña~station (IZO; 2373 m a.s.l., representative of free troposphere (FT conditions, is presented. Diurnal and seasonal O₃ variations as well as the O₃ trend (0.19 ± 0.05 % yr⁻¹ or 0.09 ppbv yr⁻¹, are assessed. A climatology of O₃ transport pathways using backward trajectories shows that higher O₃ values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O₃ is transported from the Saharan continental boundary layer (CBL. O₃ data have been compared with PM₁₀, ²¹⁰Pb, ⁷Be, potential vorticity (PV and carbon monoxide (CO. A clear negative logarithmic relationship was observed between PM₁₀ and surface O₃ for all seasons. A similar relationship was found between O₃ and ²¹⁰Pb. The highest daily O₃ values (90th percentile are observed in spring and in the first half of summer time. A positive correlation between O₃ and PV, and between O₃ and ⁷Be is found throughout the year, indicating that relatively high surface O₃ values at IZO originate from the middle and upper troposphere. We find a good correlation between O₃ and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O₃ from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O₃ values seem to be the result of stratosphere-to-troposphere (STT exchange processes in regions neighbouring the Canary Islands. Since 1995–1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative

An integrated database on ticks and tick-borne zoonoses in the tropics and subtropics with special reference to developing and emerging countries.

Science.gov (United States)

Vesco, Umberto; Knap, Nataša; Labruna, Marcelo B; Avšič-Županc, Tatjana; Estrada-Peña, Agustín; Guglielmone, Alberto A; Bechara, Gervasio H; Gueye, Arona; Lakos, Andras; Grindatto, Anna; Conte, Valeria; De Meneghi, Daniele

2011-05-01

Tick-borne zoonoses (TBZ) are emerging diseases worldwide. A large amount of information (e.g. case reports, results of epidemiological surveillance, etc.) is dispersed through various reference sources (ISI and non-ISI journals, conference proceedings, technical reports, etc.). An integrated database-derived from the ICTTD-3 project ( http://www.icttd.nl )-was developed in order to gather TBZ records in the (sub-)tropics, collected both by the authors and collaborators worldwide. A dedicated website ( http://www.tickbornezoonoses.org ) was created to promote collaboration and circulate information. Data collected are made freely available to researchers for analysis by spatial methods, integrating mapped ecological factors for predicting TBZ risk. The authors present the assembly process of the TBZ database: the compilation of an updated list of TBZ relevant for (sub-)tropics, the database design and its structure, the method of bibliographic search, the assessment of spatial precision of geo-referenced records. At the time of writing, 725 records extracted from 337 publications related to 59 countries in the (sub-)tropics, have been entered in the database. TBZ distribution maps were also produced. Imported cases have been also accounted for. The most important datasets with geo-referenced records were those on Spotted Fever Group rickettsiosis in Latin-America and Crimean-Congo Haemorrhagic Fever in Africa. The authors stress the need for international collaboration in data collection to update and improve the database. Supervision of data entered remains always necessary. Means to foster collaboration are discussed. The paper is also intended to describe the challenges encountered to assemble spatial data from various sources and to help develop similar data collections.

Psychometric evaluation of the Problem Areas in Diabetes (PAID survey in Southern, rural African American women with Type 2 diabetes

Directory of Open Access Journals (Sweden)

Elasy Tom A

2008-02-01

Full Text Available Abstract Background The Problem Areas in Diabetes (PAID survey is a measure of diabetes-related stress for which reported use has been in largely Caucasian populations. Our purpose was to assess the psychometric properties of the PAID in Southern rural African American women with Type 2 diabetes. Methods A convenience sample of African American women (N = 131 ranging from 21–50 years of age and diagnosed with Type 2 diabetes were recruited for a survey study from two rural Southern community health centers. Participants completed the PAID, Center for Epidemiological Studies-Depression Scale (CES-D, and the Summary of Diabetes Self-Care Activities Scale (SDSCA. Factor analysis, Cronbach's coefficient alpha, and construct validation facilitated psychometric evaluation. Results A principle component factor analysis of the PAID yielded two factors, 1 a lack of confidence subscale, and 2 a negative emotional consequences subscale. The Lack of Confidence and Negative Emotional Consequences subscales, but not the overall PAID scale, were associated with glycemic control and body mass index, respectively. Relationships with measures of depression and diabetes self-care supported construct validity of both subscales. Both subscales had acceptable (alpha = 0.85 and 0.94 internal consistency measures. Conclusion A psychometrically sound two-factor solution to the PAID survey is identified in Southern, rural African American women with Type 2 diabetes. Lack of confidence in and negative emotional consequences of diabetes self-care implementation provide a better understanding of determinants of glycemic control and weight than an aggregate of the two scales.

Rainfall, fog and throughfall dynamics in a sub-tropical ridge-top cloud forest, National Park of Garajonay (La Gomera, Canary Islands, Spain)

NARCIS (Netherlands)

García-Santos, G.; Bruijnzeel, L.A.

2011-01-01

Mixed tree-heath/beech forest is a type of subtropical montane cloud forest found on wind- and fog-exposed ridges in the Canary Islands. With a dry season of 5 months and an annual precipitation of 600-700 mm, the extra water inputs through fog interception assume particular importance in this

50 CFR 697.18 - Lobster management areas.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Lobster management areas. 697.18 Section... Measures § 697.18 Lobster management areas. The following lobster management areas are established for... American lobster EEZ management areas is available upon request to the Office of the Regional Administrator...

Vernon Bermuda Workshop: A Course in Sub-tropical Island Ecology

Science.gov (United States)

Werdell, P. Jeremy

2012-01-01

More than 30 years ago, educators in central Connecticut developed the Vernon Bermuda Workshop as a means of introducing middle- and high-school students to subtropical island ecology. Each year, after months of classroom preparation, approximately 20 top students spend one week at the Bermuda Institute of Ocean Sciences (St. George's, Bermuda) studying the local flora and fauna in both the field and laboratory. The curriculum includes an additional array of activities, ranging from historical and ecological tours to spelunking, and culminates in a series of field-observation-related presentations. I am responsible for the meteorological and oceanographic components of the curriculum. In the field, my students collect time-series of biophysical variables over the course of a day, which they use to interpret diurnal patterns and interactions amongst the variables. I also add remote-sensing and phytoplankton biology components to the curriculum - in previous years, my students have studied time-series of Sea WIFS imagery collected at Bermuda during our trip. I have been an Instructor for this Workshop since 2003. The Workshop provides an outreach activity for GSFC Code 616.

A Cluster Analytic Examination of Acculturation and Health Status among Asian Americans in the Washington DC Metropolitan Area, United States

Science.gov (United States)

Lee, Sunmin; Chen, Lu; He, Xin; Miller, Matthew J.; Juon, Hee-Soon

2013-01-01

Previous studies reported mixed findings on the relationship between acculturation and health status among Asian Americans due to different types of acculturation measures used or different Asian subgroups involved in various studies. We aim to fill the gap by applying multiple measures of acculturation in a diverse sample of Asian subgroups. A cross sectional study was conducted among Chinese, Korean and Vietnamese Americans in Washington D.C. Metropolitan Area to examine the association between health status and acculturation using multiple measures including the Suinn-Lew Asian Self-Identity Acculturation (SL-ASIA) scale, clusters based on responses to SL-ASIA, language preference, length of stay, age at arrival in the United Sates and self-identity. Three clusters (Asian (31%); Bicultural (47%); and American (22%)) were created by using a two-step hierarchical method and Bayesian Information Criterion values. Across all the measures, more acculturated individuals were significantly more likely to report good health than those who were less acculturated after adjusting for covariates. Specifically, those in the American cluster were 3.8 times (95% Confidence Interval (CI): 2.2, 6.6) more likely and those in the Bicultural cluster were 1.7 times more likely (95% CI: 1.1, 2.4) to report good health as compared to those in the Asian cluster. When the conventional standardized SL-ASIA summary score (range: −1.4 to 1.4) was used, a one point increase was associated with 2.2 times greater odds of reporting good health (95% CI: 1.5, 3.2). However, the interpretation may be challenging due to uncertainty surrounding the meaning of a one point increase in SL-ASIA summary score. Among all the measures used, acculturation clusters better approximated the acculturation process and provided us with a more accurate test of the association in the population. Variables included in this measure were more relevant for our study sample and may have worked together to capture the

Large scale features and energetics of the hybrid subtropical low `Duck' over the Tasman Sea

Science.gov (United States)

Pezza, Alexandre Bernardes; Garde, Luke Andrew; Veiga, José Augusto Paixão; Simmonds, Ian

2014-01-01

New aspects of the genesis and partial tropical transition of a rare hybrid subtropical cyclone on the eastern Australian coast are presented. The `Duck' (March 2001) attracted more recent attention due to its underlying genesis mechanisms being remarkably similar to the first South Atlantic hurricane (March 2004). Here we put this cyclone in climate perspective, showing that it belongs to a class within the 1 % lowest frequency percentile in the Southern Hemisphere as a function of its thermal evolution. A large scale analysis reveals a combined influence from an existing tropical cyclone and a persistent mid-latitude block. A Lagrangian tracer showed that the upper level air parcels arriving at the cyclone's center had been modified by the blocking. Lorenz energetics is used to identify connections with both tropical and extratropical processes, and reveal how these create the large scale environment conducive to the development of the vortex. The results reveal that the blocking exerted the most important influence, with a strong peak in barotropic generation of kinetic energy over a large area traversed by the air parcels just before genesis. A secondary peak also coincided with the first time the cyclone developed an upper level warm core, but with insufficient amplitude to allow for a full tropical transition. The applications of this technique are numerous and promising, particularly on the use of global climate models to infer changes in environmental parameters associated with severe storms.

Impact of Geography and Climate on the Genetic Differentiation of the Subtropical Pine Pinus yunnanensis.

Science.gov (United States)

Wang, Baosheng; Mao, Jian-Feng; Zhao, Wei; Wang, Xiao-Ru

2013-01-01

Southwest China is a biodiversity hotspot characterized by complex topography, heterogeneous regional climates and rich flora. The processes and driving factors underlying this hotspot remain to be explicitly tested across taxa to gain a general understanding of the evolution of biodiversity and speciation in the region. In this study, we examined the role played by historically neutral processes, geography and environment in producing the current genetic diversity of the subtropical pine Pinus yunnanensis. We used genetic and ecological methods to investigate the patterns of genetic differentiation and ecological niche divergence across the distribution range of this species. We found both continuous genetic differentiation over the majority of its range, and discrete isolated local clusters. The discrete differentiation between two genetic groups in the west and east peripheries is consistent with niche divergence and geographical isolation of these groups. In the central area of the species' range, population structure was shaped mainly by neutral processes and geography rather than by ecological selection. These results show that geographical and environmental factors together created stronger and more discrete genetic differentiation than isolation by distance alone, and illustrate the importance of ecological factors in forming or maintaining genetic divergence across a complex landscape. Our findings differ from other phylogenetic studies that identified the historical drainage system in the region as the primary factor shaping population structure, and highlight the heterogeneous contributions that geography and environment have made to genetic diversity among taxa in southwest China.

American Women and American Studies.

Science.gov (United States)

Chmaj, Betty E.

The American Studies Association (ASA) is an interprofessional group, representing a cross-section of persons from American literature, American history, the social sciences, philosophy, archeology, Black Studies, Urban Studies, American Studies, and others. This document by the ASA Commission on the Status of Women includes: (1) a report of the…

[Spatial and/or olfactory memory in sandflies in an endemic area for American cutaneous leishmaniasis, southern Brazil].

Science.gov (United States)

Freitas, Janaína Sales de; Reinhold-Castro, Kárin Rosi; Casanova, Cláudio; Silva, Joseane Padilha da; Previdelli, Isolde; Teodoro, Ueslei

2009-01-01

The results from an investigation on the possibility that sandflies in an endemic area for American cutaneous leishmaniasis, in the state of Paraná, may have memory are reported. Sandflies were caught in Recanto Marista, Doutor Camargo, State of Paraná, Brazil, using Falcão traps in two chicken sheds (G1 and G2), between November 15 and 26, 2007. A total of 2,080 sandflies were caught (1,000 in G1 and 1,080 in G2) and these were marked and released. Nyssomyia neivai was the most (90.5%) frequent species. Out of the total released, 168 sandflies (8%) were recaptured and the recapture rate in G2 was significant. The results show that it is possible that spatial or olfactory memory and/or host loyalty exists, and that this will guide the sandflies in recognizing the places where sources of blood are available.

Biodiversity of frog haemoparasites from sub-tropical northern KwaZulu-Natal, South Africa.

Science.gov (United States)

Netherlands, Edward C; Cook, Courtney A; Kruger, Donnavan J D; du Preez, Louis H; Smit, Nico J

2015-04-01

Since South Africa boasts a high biodiversity of frog species, a multispecies haemoparasite survey was conducted by screening the blood from 29 species and 436 individual frogs. Frogs were collected at three localities in sub-tropical KwaZulu-Natal, a hotspot for frog diversity. Twenty per cent of the frogs were infected with at least one of five groups of parasites recorded. Intraerythrocytic parasites comprising Hepatozoon, Dactylosoma, and viral or bacterial organisms, as well as extracellular parasites including trypanosomes and microfilarid nematodes were found. A significant difference (P frog species. None of those species described as purely terrestrial and aquatic were infected. Hepatozoon and Trypanosoma species accounted for most of the infections, the former demonstrating significant differences in intensity of infection across species, families and habitat types (P = 0.028; P = 0.006; P = 0.007 respectively). Per locality, the first, the formally protected Ndumo Game Reserve, had the highest biodiversity of haemoparasite infections, with all five groups of parasites recorded. The other two sites, that is the area bordering the reserve and the Kwa Nyamazane Conservancy, had a lower diversity with no parasite infections recorded and only Hepatozoon species recorded respectively. Such findings could be ascribed to the anthropogenic impact on the latter two sites, the first by the rural village activities, and the second by the bordering commercial sugar cane agriculture. Future studies should include both morphological and molecular descriptions of the above parasites, as well as the identification of potential vectors, possibly clarifying the effects human activities may have on frog haemoparasite life cycles and as such their biodiversity.

Seasonal implications on toxicity biomarkers of Loricariichthys anus (Valenciennes, 1835) from a subtropical reservoir.

Science.gov (United States)

do Amaral, Aline Monique Blank; de Lima Costa Gomes, Jeane; Weimer, Gustavo Henrique; Marins, Aline Teixeira; Loro, Vania Lucia; Zanella, Renato

2018-01-01

Cropping systems based on intensive land use and continuous application of agricultural chemicals inflict a threat to aquatic organisms since these substances will inevitably be carried in to water bodies where they can accumulate, particularly in lentic sites. Pesticides exposure in aquatic animals can cause changes that can be quantified through biomarkers. Thus, this study aimed to investigate the effects of season on oxidative stress and neurotoxicity biomarkers in Loricariichthys anus from a subtropical reservoir surrounded by agricultural areas in southern Brazil. Ten armored catfish were collected from six sites in February and August 2016. Pesticides present in the water, sediment and muscle were identified and quantified. No pesticides were detected either in sediment nor in muscle. During the winter, the water contained atrazine, imidacloprid, simazine, azoxystrobin, and propoxur; however, in summer, only atrazine was present in the water. In the winter, there was an increase in the hepatic GST activity and in GPx that kept lipid peroxidation (TBARS) constant and, in the summer, there was an increase in metallothioneins levels. In the gills, variables related to summer were possibly responsible for the elevation of GST, GPx and TBARS; during the winter, there was greater carbonylation of proteins. In the winter, the increased AChE activity in brain and muscle tissue was related to carbonylation of proteins in brain. Although the amount of pesticides detected in the water was low, chronic exposure in addition to environmental variations can cause direct and indirect effects on L. anus population. Copyright © 2017 Elsevier Ltd. All rights reserved.

Deployment Area Selection and Land Withdrawal/Acquisition. M-X/MPS (M-X/Multiple Protective Shelter) Environmental Technical Report. Native Americans Nevada/Utah.

Science.gov (United States)

1981-10-02

The malevolent goals of an evil shaman were accomplished primarily through psychic activity (i.e., by willing that a person fall ill). In some cases...older) Employed Unemployed Rate Duckwater 62 27 35 56.0 Yomba 39 21 18 53.8 Goshute 53 28 25 47.0 Moapa 98 63 35 36.0 Las Vegas 32 29 3 9.4 Ely 79 40 39... unemployed Native Americans who are enrolled at reservations and colonies in the study areas. The Region of Influence (RO) and the AOAs are defined in

Diversity and Spatial Structure of Belowground Plant–Fungal Symbiosis in a Mixed Subtropical Forest of Ectomycorrhizal and Arbuscular Mycorrhizal Plants

Science.gov (United States)

Toju, Hirokazu; Sato, Hirotoshi; Tanabe, Akifumi S.

2014-01-01

Plant–mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant–fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant–fungal symbiosis in subtropical forests is complex in that it includes “non-typical” plant–fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in

Diversity and spatial structure of belowground plant-fungal symbiosis in a mixed subtropical forest of ectomycorrhizal and arbuscular mycorrhizal plants.

Science.gov (United States)

Toju, Hirokazu; Sato, Hirotoshi; Tanabe, Akifumi S

2014-01-01

Plant-mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant-fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant-fungal symbiosis in subtropical forests is complex in that it includes "non-typical" plant-fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in that

Land use effect and hydrological control on nitrate yield in subtropical mountainous watersheds

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J.-C. Huang

2012-03-01

Full Text Available Nitrate export in small subtropical watersheds is rarely observed and the estimation of individual land use nitrate yield from a mixed combination within catchments has scarcely been studied. In this study the nitrate concentrations at 16 nested catchments in the Chi-Chia-Wan watershed in Central Taiwan were measured during 2007–2008. A 3-layer TOPMODEL was applied to estimate daily discharge for ungauged sub-catchments. The observed nitrate concentrations and the simulated discharges were used for nitrate flux estimations through four flux methods. Meanwhile, a new deconvolution computation was developed to resolve the nitrate yield of each land use from within the mixed combinations.

The results showed that the observed mean NO₃-N concentration in relatively pristine catchments was approximately 0.145 ± 0.103 mg l⁻¹, which is comparable with other forestry catchments around the world. However, the higher rainfall/runoff, substantial N deposition, and other nitrogen sources resulted in significantly higher annual export of approximately 238–1018 kg-N km⁻² yr⁻¹. Our deconvolution computation showed that the background yield of natural forestry was ~351 ±62 kg-N km⁻² yr⁻¹. On the other hand, the extremely high nitrate yield of active farmland was ~308, 170 ± 19 241 kg-N km⁻² yr⁻¹ due to over-fertilization. The deconvolution computation technique is capable of tracing the mixed signals at the outlet back to the nitrate productions from varied land use patterns. It advances the application of river monitoring network. The typical values of nitrate yields can serve as a guideline for land management. Comparing the nitrogen input and output, we found some nitrogen missing in the cycling which may indicate certain removal processes and we therefore suggest further study to be carried out to fully understand nitrogen cycling in

Estuarine demersal fish assemblage from a transition region between the tropics and the subtropics of the South Atlantic

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Mauricio Hostim-Silva

2013-06-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2013v26n3p153 Estuarine demersal fish assemblage from a transition region between the tropics and the subtropics of the South Atlantic. The coastal state of Espírito Santo is in the central region of Brazil, where biological productivity is considered low. The objective of this work is to present a current list of demersal, estuarine fish from northern Espírito Santo. This work is based on the compilation of data collected monthly using trawl nets. The ichthyofauna comprises 57 species, within 10 orders and 32 families. The family Sciaenidae has the largest number of species (8, followed by Carangidae (4 and Gerreidae (4. This coincides with what has been found for the Brazilian coast and for the coast of the South Atlantic. It is important to note that the total species richness in the estuaries of northern Espírito Santo is lower than other estuaries of the South West Atlantic coast. Most of the species are widely distributed in the Western Atlantic. Only a small part (14% of the fauna of northern Espírito Santo was evaluated in regards to risk of extinction, but conservation should be prioritized in the area due to overexploitation of species.

Sea-level driven glacial-age refugia and post-glacial mixing on subtropical coasts, a palaeohabitat and genetic study.

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Dolby, Greer A; Hechinger, Ryan; Ellingson, Ryan A; Findley, Lloyd T; Lorda, Julio; Jacobs, David K

2016-11-30

Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify and assess a sea-level-driven recolonization process following the Last Glacial Maximum (LGM). Our palaeohabitat modelling reveals dramatic changes in estuarine habitat distribution along the coast of California (USA) and Baja California (Mexico). At the LGM (approx. 20 kya), when sea level was approximately 130 m lower, the palaeo-shoreline was too steep for tidal estuarine habitat formation, eliminating this habitat type from regions where it is currently most abundant, and limiting such estuaries to a northern and a southern refugium separated by 1000 km. We assess the recolonization of estuaries formed during post-LGM sea-level rise through examination of refugium-associated alleles and approximate Bayesian computation in three species of estuarine fishes. Results reveal sourcing of modern populations from both refugia, which admix in the newly formed habitat between the refuges. We infer a dramatic peak in habitat area between 15 and 10 kya with subsequent decline. Overall, this approach revealed a previously undocumented dynamic and integrated relationship between sea-level change, coastal processes and population genetics. These results extend glacial refugial dynamics to unglaciated subtropical coasts and have significant implications for biotic response to predicted sea-level rise. © 2016 The Author(s).

Mesoscale modeling of smoke transport over Central Africa: influences of trade winds, subtropical high, ITCZ and vertical statistics

Science.gov (United States)

Yang, Z.; Wang, J.; Hyer, E. J.; Ichoku, C. M.

2012-12-01

A fully-coupled meteorology-chemistry-aerosol model, Weather Research and Forecasting model with Chemistry (WRF-Chem), is used to simulate the transport of smoke aerosol over the Central Africa during February 2008. Smoke emission used in this study is specified from the Fire Locating and Modeling of Burning Emissions (FLAMBE) database derived from Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. Model performance is evaluated using MODIS true color images, measured Aerosol Optical Depth (AOD) from space-borne MODIS (550 nm) and ground-based AERONET (500 nm), and Cloud-Aerosol Lidar data with Orthogonal Polarization (CALIOP) level 1 and 2 products. The simulated smoke transport is in good agreement with the validation data. Analyzing from three smoke events, smoke is constrained in a narrow belt between the Equator and 10°N near the surface, with the interplay of trade winds, subtropical high, and ITCZ. At the 700 hpa level, smoke expands farther meridionally. Topography blocks the smoke transport to the southeast of study area, because of high mountains located near the Great Rift Valley region. The simulation with injection height of 650 m is consistent with CALIOP measurements. The particular phenomenon, aerosol above cloud, is studied statistically from CALIOP observations. The total percentage of aerosol above cloud is about 5%.

Evaluation of soil carbon pools after the addition of prunings in subtropical orchards placed in terraces

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Márquez San Emeterio, Layla; Martín Reyes, Marino Pedro; Ortiz Bernad, Irene; Fernández Ondoño, Emilia; Sierra Aragón, Manuel

2017-04-01

The amount of carbon that can be stored in a soil depends on many factors, such as the type of soil, the chemical composition of plant rests and the climate, and is also highly affected by land use and soil management. Agricultural ecosystems are proved to absorb a large amount of CO2 from the atmosphere through several sustainable management practices. In addition, organic materials such as leaves, grass, prunings, etc., comprise a significant type of agricultural practices as a result of waste recycling. The aim of this research was to evaluate the effects of the addition of different organic prunings on the potential for carbon sequestration in agricultural soils placed in terraces. Three subtropical orchards were sampled in Almuñécar (Granada, S Spain): mango (Mangifera indica L.), avocado (Persea americana Mill.) and cherimoya (Annonacherimola Mill.). The predominant climate is Subtropical Mediterranean and the soil is an Eutric Anthrosol. The experimental design consisted in the application of prunings from avocado, cherimoya and mango trees, placed on the surface soil underneath their correspondent trees, as well as garden prunings from the green areas surrounding the town center on the surface soils under the three orchard trees. Control experiences without the addition of prunings were also evaluated. These experiences were followed for three years. Soil samples were taken at4 cm depth. They were dried for 3-4 days and then sieved (<2 mm).Total soil organic C, water-soluble soil organic C, mineral-associated organic C and non-oxidable C were analyzed and expressed as carbon pools (Mg C ha-1for total soil organic C, or Kg C ha-1for the others). The results showed an increase of all organic carbon pools in all pruning treatments compared to the control experiences. Differences in total organic carbon pool were statistically significant between soils under avocado prunings and their control soil, and between soils under garden prunings with cherimoya and

Organic tracers of primary biological aerosol particles at subtropical Okinawa Island in the western North Pacific Rim

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Zhu, Chunmao; Kawamura, Kimitaka; Kunwar, Bhagawati

2015-06-01

Primary biological aerosol particles (PBAPs) play an important role in affecting atmospheric physical and chemical properties. Aerosol samples were collected at Cape Hedo, Okinawa Island, Japan, from October 2009 to February 2012 and analyzed for five primary saccharides and four sugar alcohols as PBAP tracers. We detected high levels of sucrose in spring when blossoming of plants happens and prolifically emits pollen to the air. Concentrations of glucose, fructose, and trehalose showed levels higher than the other saccharides in spring in 2010. In comparison, primary saccharide levels were mutually comparable in spring, summer, and autumn in 2011, indicating the interannual variability of their local production in subtropical forests, which is driven by local temperature and radiation. High trehalose events were found to be associated with Asian dust outflows, indicating that Asian dust also contributes to PBAPs at Okinawa. Sugar alcohols peaked in summer and correlated with local precipitation and temperature, indicating high microbial activities. Positive matrix factorization analysis confirmed that the PBAPs are mainly derived from local vegetation, pollen, and fungal spores. A higher contribution of PBAP tracers to water-soluble organic carbon (WSOC) was found in summer (14.9%). The annual mean ambient loadings of fungal spores and PBAPs were estimated as 0.49 µg m-3 and 4.12 µg m-3, respectively, using the tracer method. We report, for the first time, year-round biomarkers of PBAP and soil dust and their contributions to WSOC in the subtropical outflow region of the Asian continent.

Inorganic and organic nitrogen acquisition by a fern Dicranopteris dichotoma in a subtropical forest in South China.

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Xingliang Xu

Full Text Available The fern Dicranopteris dichotoma is an important pioneer species of the understory in Masson pine (Pinus massoniana forests growing on acidic soils in the subtropical and tropical China. To improve our understanding of the role of D. dichotoma in nitrogen (N uptake of these forests, a short-term (15N experiment was conducted at mountain ridge (MR, with low N level and mountain foot (MF, with high N level. We injected (15N tracers as (15NH4, (15NO3 or (15N-glycine into the soil surrounding each plant at both MR and MF sites. Three hours after tracer injection, the fern D. dichotoma took up 15NH4+ significantly faster at MF than at MR, but it showed significantly slower uptake of (15NO3- at MF than at MR. Consequently, (15NO3- made greater contribution to the total N uptake (50% to the total N uptake at MR than at MF, but (15N-glycine only contributed around 11% at both sites. Twenty-four hours after tracer injection, D. dichotoma preferred (15NH4+ (63% at MR, whereas it preferred (15NO3- (47% at MF. We concluded that the D. dichotoma responds distinctly in its uptake pattern for three available N species over temporal and spatial scales, but mainly relies on inorganic N species in the subtropical forest. This suggests that the fern employs different strategies to acquire available N which depends on N levels and time.

Battling pollution in coastal areas | IDRC - International ...

International Development Research Centre (IDRC) Digital Library (Canada)

At the same time they represent subtropical and tropical climates and fresh and salt ... IDRC Research Chair in Environmental Health and Management Federal ... Author of more than 100 peer-reviewed journal articles, he also serves on the ...

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

A. Morel; H. Claustre; B. Gentili

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account ...

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

Morel, A.; Claustre, H.; Gentili, B.

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") acc...

Everyday problem solving in African Americans and European Americans with Alzheimer's disease: an exploratory study.

Science.gov (United States)

Ripich, Danielle N; Fritsch, Thomas; Ziol, Elaine

2002-03-01

In this exploratory study, we compared the performance of 10 African American and 26 European American persons with early- to mid-stage Alzheimer's disease (AD) to 20 nondemented elderly (NE), using a shortened version of the Test of Problem Solving (TOPS). The TOPS measures verbal reasoning to solve everyday problems in five areas: explaining inferences, determining causes, answering negative why questions, determining solutions, and avoiding problems. Six linguistic measures were also examined: total utterances, abandoned utterances, length of utterances, maze words, questions, and total words. NE performed better than AD subjects on all but one measure of verbal reasoning ability. AD subjects also showed a trend to use more total utterances and abandoned utterances than NE. For the AD group, no ethnic differences were found for verbal reasoning or linguistic measures. The findings from this preliminary investigation suggest that, compared to European Americans, African American persons with AD demonstrate similar everyday problem solving and linguistic skills. Thus, assessments such as TOPS that examine everyday problem solving may be a useful nonbiased evaluation tool for persons with AD in these two ethnic groups.

Effects of nutrient enrichment derived from fish farming activities on macroinvertebrate assemblages in a subtropical region of Hong Kong.

Science.gov (United States)

Gao, Qin-Feng; Cheung, Kwok-Leung; Cheung, Siu-Gin; Shin, Paul K S

2005-01-01

To study the correlation between nutrient enrichment derived from fish farming activities and changes in macrobenthic assemblages, a one-year field study was conducted in Kau Sai Bay marine fish culture zone of Hong Kong. Bimonthly sediment samples were collected at six stations: two at the fish cages, two near the boundary of the fish culture area, and two reference sites further away from the culture area. Sediment physico-chemical characteristics in terms of silt/clay fraction, moisture content, total organic carbon (TOC), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) were analyzed. The macrobenthos (>0.5 mm) present in the sediment were sorted, identified and enumerated. On average, TOC, TKN and TP levels at the fish cage stations were 82.8%, 128.5% and 1315.7% higher than those at the reference stations, respectively. As a result, the N:P molar ratio was greatly reduced from 8.75 at the reference stations to 1.83 at the fish cage stations. Univariate and multivariate analyses revealed that diversity of macrofauna was significantly reduced and community structure differed at the fish cage stations relative to the reference sites. The intermediary stations near the fish culture area showed a transitional state of disturbance. Faunal diversity was negatively correlated with nutrient level, reflecting the adverse impacts of nutrient enrichment derived from fish farming activities on the benthic assemblages. Whilst in subtropical Asia-Pacific trash fish is the major feed for fish culture resulting in a higher nutrient loading and nutrient ratio accumulated in the sediment beneath the fish rafts, the effects of nutrient enrichment on macrobenthic assemblages are comparable to that in temperate waters owing to relatively high sediment metabolism rate and smaller fish culture scale in Hong Kong.

Prevalence of Colacium vesiculosum (Colaciales: Euglenophyceae on planktonic crustaceans in a subtropical shallow lake of Argentina

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Yolanda Zalocar

2011-09-01

Full Text Available Colacium vesiculosum (Euglenophyceae is an epibiont common on planktonic microcrustaceans of continental waters. The interaction between epibionts and substrate organisms is not very well known, particularly in subtropical environments of South America. In the present work, we analyzed the prevalence, density, biomass and attachment sites of C. vesiculosum on planktonic microcrustaceans from Paiva Lake, a subtropical lake of Argentina. With the aim to evaluate whether epibionts affect the filtering rates of Notodiaptomus spiniger, the dominant planktonic crustacean, we carried out bioassays using phytoplankton Colacium vesiculosum Ehrenberg (Euglenophyceae es un epibionte común en microcrustáceos del plancton de aguas continentales. La interacción epibiontes y organismo substrato es poco conocida, particularmente en ambientes subtropicales de América del Sur. Se analiza la prevalencia, densidad, biomasa y sitios de adhesión de C. vesiculosum en microcrustáceos planctónicos de un lago subtropical de Argentina. Con el fin de evaluar si los epibiontes afectan la tasa de filtración de Notodiaptomus spiniger Brian, crustáceo dominante del zooplancton, se realizaron bioensayos utilizando el fitoplancton <53µm. Los crustáceos fueron muestreados con un tubo de PVC (1m de largo, 10cm de diámetro filtrándose 50L de agua a través de una red de 53µm de abertura de malla. El recuento de los microcrustáceos se realizó en cámaras de Bogorov bajo microscopio estereoscópico. Los organismos infectados fueron separados y observados al microscopio fotónico para determinaciones de densidad y biovolumen de los epibiontes, y su distribución en el exoesqueleto. La prevalencia de C. vesiculosum fue mayor en crustáceos adultos que en estadíos larvales y juveniles. El grupo más infestado fue el de los copépodos calanoideos en relación con su alta densidad. Los sitios de adhesión sobre el exoesqueleto fueron las regiones del cuerpo que durante la

Tree species traits but not diversity mitigate stem breakage in a subtropical forest following a rare and extreme ice storm.

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Karin Nadrowski

Full Text Available Future climates are likely to include extreme events, which in turn have great impacts on ecological systems. In this study, we investigated possible effects that could mitigate stem breakage caused by a rare and extreme ice storm in a Chinese subtropical forest across a gradient of forest diversity. We used Bayesian modeling to correct stem breakage for tree size and variance components analysis to quantify the influence of taxon, leaf and wood functional traits, and stand level properties on the probability of stem breakage. We show that the taxon explained four times more variance in individual stem breakage than did stand level properties; trees with higher specific leaf area (SLA were less susceptible to breakage. However, a large part of the variation at the taxon scale remained unexplained, implying that unmeasured or undefined traits could be used to predict damage caused by ice storms. When aggregated at the plot level, functional diversity and wood density increased after the ice storm. We suggest that for the adaption of forest management to climate change, much can still be learned from looking at functional traits at the taxon level.

Cancer statistics for African Americans, 2013.

Science.gov (United States)

DeSantis, Carol; Naishadham, Deepa; Jemal, Ahmedin

2013-05-01

In this article, the American Cancer Society estimates the number of new cancer cases and deaths for African Americans and compiles the most recent data on cancer incidence, mortality, survival, and screening prevalence based upon incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. It is estimated that 176,620 new cases of cancer and 64,880 deaths will occur among African Americans in 2013. From 2000 to 2009, the overall cancer death rate among males declined faster among African Americans than whites (2.4% vs 1.7% per year), but among females, the rate of decline was similar (1.5% vs 1.4% per year, respectively). The decrease in cancer death rates among African American males was the largest of any racial or ethnic group. The reduction in overall cancer death rates since 1990 in men and 1991 in women translates to the avoidance of nearly 200,000 deaths from cancer among African Americans. Five-year relative survival is lower for African Americans than whites for most cancers at each stage of diagnosis. The extent to which these disparities reflect unequal access to health care versus other factors remains an active area of research. Overall, progress in reducing cancer death rates has been made, although more can and should be done to accelerate this progress through ensuring equitable access to cancer prevention, early detection, and state-of-the-art treatments. Copyright © 2013 American Cancer Society, Inc.

Linking Seasonal Variations in the Spectral Slope of Chromophoric Dissolved Organic Matter (CDOM) with Apparent Oxygen Utilization and Excess Nitrogen (DINxs) in the North Atlantic Subtropical Gyre

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McDonald, N.; Barnes, R.; Nelson, N. B.

2016-02-01

The optically active or chromophoric fraction of dissolved organic matter (CDOM) is a topic of much interest to researchers due to its role in many biogeochemical processes in the global oceans. As CDOM effectively regulates the underwater light field, its influences on photosynthesis and primary productivity are significant. Despite recognition of its importance in biogeochemical cycles in natural waters, its chemical composition remains nebulous, due to photochemical processes, as well as spatial and temporal variations in composition. Understanding of CDOM composition and links to ocean processes is especially complex in pelagic, oligotrophic waters such as the North Atlantic Subtropical Gyre. In this region, minimum CDOM concentrations have been observed and it is decoupled from both dissolved organic carbon (DOC) and from net primary production (NPP). As CDOM absorbance has been shown to influence estimates of NPP from remote sensing models in the subtropical gyres, and as it has the potential to serve as an invaluable tracer of ocean DOM cycling, a better understanding of links between the optical properties of CDOM and biogeochemical processes in the subtropical gyres is crucial. In this study, monthly depth profiles of CDOM absorbance (between 1m and 3000m) were measured for a period of five years at the Bermuda Atlantic Timeseries Site (BATS) in the North Atlantic Subtropical Gyre to investigate seasonal variations and periodicity in CDOM optical properties. From this data, the spectral slope ratio (Sr) was calculated according to Helms et. al, 2008. Sr can be a useful tool in eliciting information about molecular weight, diagenetic state and microbial processes affecting CDOM composition, especially when coupled with other diagnostic parameters. In this study multivariate analysis techniques were utilized to examine links between Sr and ancillary parameters including apparent oxygen utilization (AOU) and excess nitrogen (DINxs) both of which can be a

Interpretation of Upper-Storey Canopy Area in Subtropical Broad-leaved Forests in Okinawa Island Using Laser Scanning Data

International Nuclear Information System (INIS)

Noor Janatun Naim Jemali; Shiba, M.; Azita Ahmad Zawawi; Noor Janatun Naim Jemali

2015-01-01

Conventional forest inventory practice took huge of effort, and is time- and cost- consuming. With the aid of remote sensing technology by light detection and ranging (LiDAR), those unbearable factors could be minimized. LiDAR is able to capture forest characteristic information and is well known for estimating forest structure accurately in many studies. Forest monitoring related to forest resource inventory (FRI) becomes more effective by utilizing LiDAR data and it is tremendously useful, especially to distinguish information on density, growth and distribution of trees in a selected area. In this study, LiDAR data was utilized aimed to delineate crown cover and estimate upper-storey canopy area in Yambaru Forest using object-based segmentation and classification techniques. Agreement between field survey and LiDAR data analysis showed that only 33.7 % of upper-storey canopy area was successfully delineated. The low accuracy level of canopy detection in Yambaru Forest area was expected mainly due to tree structure, density and topographic condition. (author)

Dominant Species in Subtropical Forests Could Decrease Photosynthetic N Allocation to Carboxylation and Bioenergetics and Enhance Leaf Construction Costs during Forest Succession.

Science.gov (United States)

Xiao, Yihua; Liu, Shirong; Tong, Fuchun; Chen, Bufeng; Kuang, Yuanwen

2018-01-01

It is important to understand how eco-physiological characteristics shift in forests when elucidating the mechanisms underlying species replacement and the process of succession and stabilization. In this study, the dominant species at three typical successional stages (early-, mid-, and late-succession) in the subtropical forests of China were selected. At each stage, we compared the leaf construction costs (CC), payback time (PBT), leaf area based N content ( N A ), maximum CO 2 assimilation rate ( P max ), specific leaf area (SLA), photosynthetic nitrogen use efficiency (PNUE), and leaf N allocated to carboxylation ( N C ), and to bioenergetics ( N B ). The relationships between these leaf functional traits were also determined. The results showed that the early-succession forest is characterized with significantly lower leaf CC, PBT, N A , but higher P max , SLA, PNUE, N C , and N B , in relation to the late-succession forest. From the early- to the late-succession forests, the relationship between P max and leaf CC strengthened, whereas the relationships between N B , N C , PNUE, and leaf CC weakened. Thus, the dominant species are able to decrease the allocation of the photosynthetic N fraction to carboxylation and bioenergetics during forest succession. The shift in these leaf functional traits and their linkages might represent a fundamental physiological mechanism that occurs during forest succession and stabilization.

Terrestrial gamma radiation dose rate in Ryukyu Islands, subtropical region of Japan

International Nuclear Information System (INIS)

Furukawa, M.; Shiroma, M.; Motomura, D.; Fujioka, S.; Kawakami, T.; Yasuda, Y.; Arakawa, K.; Fukahori, K.; Jyunicho, M.; Ishikawa, S.; Ohomoto, T.; Kina, S.; Shiroma, Y.; Masuda, N.; Hiraoka, H.; Shingaki, R.; Akata, N.; Zhuo, W.; Tokonami, S.

2015-01-01

In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h -1 , respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time. (authors)

A comparison of skin tone discrimination among African American men: 1995 and 2003

OpenAIRE

Uzogara, Ekeoma E.; Lee, Hedwig; Abdou, Cleopatra M.; Jackson, James S.

2014-01-01

This study investigated perceptions of skin tone discrimination among adult African American men. Research suggests that through negative African American stereotypes, out-group members (Whites) perceive light-skinned African Americans favorably and dark-skinned African Americans unfavorably. However, it is unclear how treatment by in-group members (other African Americans) uniquely affects men. Using data from the 1995 Detroit Area Study and the 2003 National Survey of America...

Physical nutrient transport in the North Atlantic Subtropical Gyre

Science.gov (United States)

Jenkins, W.; Lott, D. E.

2009-04-01

Use of the helium-3 flux gauge to estimate the physically mediated flux of new nutrients to the euphotic zone of the North Atlantic subtropical gyre broadly suggests a pathway whereby inorganic nutrients that have been remineralized within the main thermocline may be returned to the seasonally accessible layer in the Sargasso Sea: the so-called "Nutrient Spiral" (Jenkins and Doney (2003), Glob. Biog. Cyc., 17(4), doi:1110.1029/2003GB002085.) The challenge, however, is identifying the exact mechanism whereby this occurs. One possible process is that of "obduction", whereby the combination of strong advection and rapidly deepening winter mixed layers result in the effective outcropping of substantial amounts of thermocline nutrients and tritiugenic helium-3. We present here a quantitative estimate based on hydrographic sections and geostrophic transports of the fluxes and transformations of both tritugenic helium-3 and nitrate within the basin, and attempt to relate these estimates to the specific shallow-water behaviors of these tracers, and their global and regional physical transports. An important constraint for these estimates lies in the evolving distributions of the transient tracers tritium and helium-3. We compare these results with other tracer-based estimates of new, net-community, and export production.

ABOVE GROUND BIOMASS MICRONUTRIENTS IN A SEASONAL SUBTROPICAL FOREST

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Hamilton Luiz Munari Vogel

2015-06-01

Full Text Available In the above ground biomass of a native forest or plantation are stored large quantities of nutrients, with few studies in the literature, especially concerning micronutrients. The present work aimed to quantify the micronutrients in above ground biomass in a Seasonal Subtropical forest in Itaara-RS, Brazil. For the above ground biomass evaluation, 20 trees of five different diameter classes were felled. The above ground biomass was separated in the following compartments: stem wood, stem bark, branches and leaves. The contents of B, Cu, Fe, Mn and Zn in the biomass samples were determined. The stock of micronutrients in the biomass for each component was obtained based on the estimated dry biomass, multiplied by the nutrient content. The total production of above ground biomass was estimated at 210.0 Mg.ha-1. The branches, stem wood, stem bark and leaves corresponded to 48.8, 43.3, 5.4 and 2.4% of the above ground biomass. The lower levels of B, Cu, Fe and Mn are in stem wood, except for Zn; in the branches and trunk wood are the largest stocks of B, Cu, Fe and Mn. In the branches, leaves and trunk bark are stored most micronutrients, pointing to the importance of these to remain on the soil.

American Indians, Place Meanings and the Old/New West

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Leo McAvoy

2002-01-01

The American West includes millions of acres of national parks, forests and other protected lands. These landscapes are often associated with sense of place and place meanings for those who live there and for people who go there for recreation and tourism. American Indian place meanings regarding national parks and protected areas are often very different from those of...

Effects of Different Biochars on Pinus elliottii Growth, N Use Efficiency, Soil N2O and CH4 Emissions and C Storage in a Subtropical Area of China

Institute of Scientific and Technical Information of China (English)

LIN Zhibin; XIE Zubin; LIU Qi; LIU Gang; Annette L.COWIE; BEI Qicheng; LIU Benjuan; WANG Xiaojie; MA Jing; ZHU Jianguo

2017-01-01

Intensive management of planted forests may result in soil degradation and decline in timber yield with successive rotations.Biochars may be beneficial for plant production,nutrient uptake and greenhouse gas mitigation.Biochar properties vary widely and are known to be highly dependent on feedstocks,but their effects on planted forest ecosystem are elusive.This study investigated the effects of chicken manure biochar,sawdust biochar and their feedstocks on 2-year-old Pinus elliottii growth,fertilizer N use efficiency (NUE),soil N2O and CH4 emissions,and C storage in an acidic forest soil in a subtropical area of China for one year.The soil was mixed with materials in a total of 8 treatments:non-amended control (CK);sawdust at 2.16 kg m-2 (SD);chicken manure at 1.26 kg m-2 (CM);sawdust biochar at 2.4 kg m-2 (SDB);chicken manure biochar at 2.4 kg m-2 (CMB);15N-fertilizer alone (10.23 atom％ 15N) (NF);sawdust biochar at 2.4 kg m-2 plus 15N-fertilizer (SDBN) and chicken manure biochar at 2.4 kg m-2 plus 15N-fertilizer (CMBN).Results showed that the CMB treatment increased P.elliottii net primary production (aboveground biomass plus litterfall) and annual net C fixation (ANCF) by about 180％ and 157％,respectively,while the the SDB treatment had little effect on P.elliottii growth.The 15N stable isotope labelling technique revealed that fertilizer NUE was 22.7％ in CK,25.5％ in the NF treatment,and 37.0％ in the CMB treatment.Chicken manure biochar significantly increased soil pH,total N,total P,total K,available P and available K.Only 2％ of the N in chicken manure biochar was available to the tree.The soil N2O emission and CH4 uptake showed no significant differences among the treatments.The apparent C losses from the SD and CM treatments were 35％ and 61％,respectively;while those from the CMB and SDB treatments were negligible.These demonstrated that it is crucial to consider biochar properties while evaluating their effects on plant growth and C

AMERICAN INDIANS AND EDUCATIONAL LABORATORIES.

Science.gov (United States)

BASS, WILLARD P.; BURGER, HENRY G.

MANY OF THE DIVERSE EDUCATIONAL PROBLEMS OF THE AMERICAN INDIAN HAVE BEEN IDENTIFIED FOR YEARS, BUT HAVE BEEN PERMITTED TO LAY DORMANT. SOCIO-ECONOMIC DISADVANTAGEMENT IS EXHIBITED IN AREAS OF INCOME, UNEMPLOYMENT, SCHOOL DROPOUT RATE, EXPECTED LIFE SPAN, INFANT MORTALITY RATE, BIRTH RATE, AND HEALTH HISTORY. COMMUNICATION PROBLEMS BLOCK THE…

Asian American Librarians and Chinese American Librarians: Their Impact on the Profession and on U.S. Communities

Directory of Open Access Journals (Sweden)

Jian-Zhong (Joe Zhou

2003-10-01

Full Text Available

頁次：14-21

Among 150,000 librarians working in the United States, about 5% were Asians and Pacific Islanders (API, who worked mainly in the academic and large public libraries. Most Asian librarians had the unique characters of bilingual and bicultural background. They not only played a key service role to the API communities in the U.S., but also served as a bridge between mainstream American culture and the Asian culture that bound the API community together for generations. The Chinese American librarians have been a major component of API librarians and their association -- Chinese American Librarians Association (CALA is one of the most active ones among U.S. minority librarians associations. Chinese American librarians worked in all areas of library profession, especially in the technical services and Asian Studies libraries. The representation of Chinese American librarians working in the management category has been below the national average, which was a common phenomenon among Asian American educators in general.

Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

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Karin Lundgren

2013-07-01

Full Text Available Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly electricity use to outdoor temperatures and humidity; modeled future predictions when facing additional heat due to climate change, related air conditioning with increased street level heat and estimated future air conditioning use in major urban areas. However, global and localized studies linking climate variables with air conditioning alone are lacking. More research and detailed data is needed looking at the effects of increasing air conditioning use, electricity consumption, climate change and interactions with the urban heat island effect. Climate change mitigation, for example using renewable energy sources, particularly photovoltaic electricity generation, to power air conditioning, and other sustainable methods to reduce heat exposure are needed to make future urban areas more climate resilient.

Application of Synthetic Storm Technique for Diurnal and Seasonal Variation of Slant Path Ka-Band Rain Attenuation Time Series over a Subtropical Location in South Africa

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J. S. Ojo

2015-01-01

Full Text Available As technology advances and more demands are on satellite services, rain-induced attenuation still creates one of the most damaging effects of the atmosphere on the quality of radio communication signals, especially those operating above 10 GHz. System designers therefore require statistical information on rain-induced attenuation over the coverage area in order to determine the appropriate transmitter and receiver characteristics to be adopted. This paper presents results on the time-varying rain characterization and diurnal variation of slant path rain attenuation in the Ka-band frequency simulated with synthetic storm techniques over a subtropical location in South Africa using 10-year rain rate time-series data. The analysis is based on the CDF of one-minute rain rate; time-series seasonal variation of rain rate observed over four time intervals: 00:00–06:00, 06:00–12:00, 12:00–18:00, and 18:00–24:00; diurnal fades margin; and diurnal variation of rain attenuation. Comparison was also made between the synthesized values and measured attenuation data. The predicted statistics are in good agreement with those obtained from the propagation beacon measurement in the area. The overall results will be needed for an acceptable planning that can effectively reduce the fade margin to a very low value for an optimum data communication over this area.

Chemical composition and antimicrobial activity of honeybee ( Apis mellifera ligustica) propolis from subtropical eastern Australia

Science.gov (United States)

Massaro, Carmelina Flavia; Simpson, Jack Bruce; Powell, Daniel; Brooks, Peter

2015-12-01

Propolis is a material manufactured by bees and contains beeswax, bee salivary secretions and plant resins. Propolis preparations have been used for millennia by humans in food, cosmetics and medicines due to its antibacterial effects. Within the hive, propolis plays an important role in bees' health, with much of its bioactivity largely dependent on the plant resins the bees select for its production. Few chemical studies are available on the chemistry of propolis produced by Australian honeybees ( Apis mellifera, Apidae). This study aimed to determine the chemical composition as well as in vitro antimicrobial effects of propolis harvested from honeybees in subtropical eastern Australia. Honeybee propolis was produced using plastic frames and multiple beehives in two subtropical sites in eastern Australia. Methanolic extracts of propolis were analysed by liquid chromatography with ultraviolet detection and high-resolution mass spectrometry (ultra-high-pressure liquid chromatography (UHPLC)-UV-high-resolution tandem mass spectrometry (HR-MS/MS)) and by gas chromatography mass spectrometry (GC-MS). The resulting chemical data were dereplicated for compound characterisation. The two crude extracts in abs. ethanol were tested in vitro by the agar diffusion and broth dilution methods, using a phenol standard solution as the positive control and abs. ethanol as the negative control. Chemical constituents were identified to be pentacyclic triterpenoids and C-prenylated flavonoids, including Abyssinoflavanone VII, Propolin C and Nymphaeol C. The two propolis crude extracts showed bactericidal effects at the minimal inhibitory concentrations of 0.37-2.04 mg mL-1 against Staphylococcus aureus ATCC 25923. However, the extracts were inactive against Klebsiella pneumoniae ATCC 13883 and Candida albicans ATCC 10231. The antistaphylococcal potential of propolis was discussed, also in relation to honeybees' health, as it warrants further investigations on the social and

Collaborative Research: Atlantic Ocean Tropical/Subtropical Processes from Seasonal to Decadal Time Scales: Model/Data, Model/Model Comparison and Model/Data Synthesis Through Assimilation

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Malannotte-Rizzoli, Paola

2003-01-01

The effort of this first year of research has been focused on the assimilation of TOPEX/Poseidon altimetric data into a primitive equation model of the Atlantic tropical/subtropical circulation. A reduced-rank, stationary Kalman filter has been constructed to assimilate the altimetric sea surface height anomaly (SHA) into the model. The goal is to assess how the inter-hemispheric transports between the Atlantic subtropics and tropics are affected by the assimilation and how the subsurface thermocline structure , and its variability ,is dynamically constrained by the SHA. The model is a reduced-gravity primitive equation GCM of the upper Atlantic Ocean between 30 S and 30 N. The assimilation scheme is an approximation to the extended Kalman filter in which the error covariances of the state estimates are calculated only in a reduced- dimension subspace. The subspace is defined by the leading empirical orthogonal functions calculated from an unconstrained model calculation. Both an identical twin experiment using simulated SHA observations and assimilation of the real TOPEX data were performed. Results from the twin experiments demonstrate the ability of the method to constrain the ocean circulation and the subsurface temperature structure. The impact on the subsurface temperature structure of TOPEX assimilation was assessed using data from expandable bathythermographs. This showed a substantial improvement in the estimated temperature variability only within 13 degrees in latitude around the equator. The impact of TOPEX SHA assimilation on zonally integrated meridional transport across different latitudes was also estimated. Again within 13 degrees from the equator both the mean amplitude and interannual variability of the surface and subsurface transports were significantly enhanced, while the transports were insensitive to the assimilation in the subtropics.

Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?

Science.gov (United States)

Wei, Hui; Chen, Xiaomei; Xiao, Guoliang; Guenet, Bertrand; Vicca, Sara; Shen, Weijun

2015-01-01

Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of Rh while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations. PMID:26670822

Effects of altitude and beehive bottom board type on wintering losses of honeybee colonies under subtropical climatic conditions

Energy Technology Data Exchange (ETDEWEB)

Ucak-Koc, A.

2014-06-01

The effects of altitude and beehive bottom board types (BBBT) on the wintering performance of honeybee colonies were investigated in the South Aegean Region of Turkey: Experiment I (E-I), with 32 colonies, in 2010-2011, and Experiment II (E-II), with 20 colonies, in 2011-2012. Each lowland (25 m) and highland (797 m) colony was divided randomly into two BBBT subgroups, open screen floor (OSF) and normal bottom floor (NBF), and wintered for about three months. In E-I, the local genotype Aegean ecotype of Anatolian bee (AE) and Italian race (ItR) were used, while in E-II, only the AE genotype was present. In E-I, the effect of wintering altitudes on the number of combs covered with bees (NCCB), and the effects of BBBT on brood area (BA) and the NCCB were found to be statistically significant (p < 0.05), but the effects of genotype on BA and NCCB were statistically insignificant (p > 0.05). In the E-II, the effect of wintering altitude on beehive weight was found to be statistically significant (p < 0.05), while its effect on the NCCB was statistically insignificant (p > 0.05). The wintering losses in the highland and lowland groups in E-I were determined to be 25% and 62.5% respectively. In contrast to this result, no loss was observed in E-II for both altitudes. In E-I, the wintering losses for both OSF and NBF groups were the same (43.75%). In conclusion, under subtropical climatic conditions, due to variations from year to year, honeybee colonies can be wintered more successfully in highland areas with OSF bottom board type. (Author)

Subsurface lateral flow from hillslope and its contribution to nitrate loading in streams through an agricultural catchment during subtropical rainstorm events

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B. Zhang

2011-10-01

loss. The results suggest that subsurface lateral flow through hydraulically stratified soil pedons have to be paid more attention for controlling non-point source surface water pollution from intensive agricultural catchment particularly in the subtropical areas with great soil infiltration.

Radiation preservation of foods of plant origin. Part IV. Subtropical fruits: citrus, grapes, and avocados

International Nuclear Information System (INIS)

Thomas, P.

1986-01-01

Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined. 128 references

Diffuse pollution and bio monitoring, Subtropical area experience

International Nuclear Information System (INIS)

Fernandez, H.

2012-01-01

This presentation is about a study carried out in Lules River Basin in San Javier, Tucuman. The state of the riverbanks, the biological quality, the nutrients in the water as well as the erosion processes were determined in Autumm.

Basin-scale variability in plankton biomass and community metabolism in the sub-tropical North Atlantic Ocean

Science.gov (United States)

Harrison, W. G.; Arístegui, J.; Head, E. J. H.; Li, W. K. W.; Longhurst, A. R.; Sameoto, D. D.

Three trans-Atlantic oceanographic surveys (Nova Scotia to Canary Islands) were carried out during fall 1992 and spring 1993 to describe the large-scale variability in hydrographic, chemical and biological properties of the upper water column of the subtropical gyre and adjacent waters. Significant spatial and temporal variability characterized a number of the biological pools and rate processes whereas others were relatively invariant. Systematic patterns were observed in the zonal distribution of some properties. Most notable were increases (eastward) in mixed-layer temperature and salinity, depths of the nitracline and chlorophyll- a maximum, regenerated production (NH 4 uptake) and bacterial production. Dissolved inorganic carbon (DIC) concentrations, phytoplankton biomass, mesozooplankton biomass and new production (NO 3 uptake) decreased (eastward). Bacterial biomass, primary production, and community respiration exhibited no discernible zonal distribution patterns. Seasonal variability was most evident in hydrography (cooler/fresher mixed-layer in spring), and chemistry (mixed-layer DIC concentration higher and nitracline shallower in spring) although primary production and bacterial production were significantly higher in spring than in fall. In general, seasonal variability was greater in the west than in the east; seasonality in most properties was absent west of Canary Islands (˜20°W). The distribution of autotrophs could be reasonably well explained by hydrography and nutrient structure, independent of location or season. Processes underlying the distribution of the microheterophs, however, were less clear. Heterotrophic biomass and metabolism was less variable than autotrophs and appeared to dominate the upper ocean carbon balance of the subtropical North Atlantic in both fall and spring. Geographical patterns in distribution are considered in the light of recent efforts to partition the ocean into distinct "biogeochemical provinces".

Prevalence of Colacium vesiculosum (Colaciales: Euglenophyceae on planktonic crustaceans in a subtropical shallow lake of Argentina

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Yolanda Zalocar

2011-09-01

Full Text Available Colacium vesiculosum (Euglenophyceae is an epibiont common on planktonic microcrustaceans of continental waters. The interaction between epibionts and substrate organisms is not very well known, particularly in subtropical environments of South America. In the present work, we analyzed the prevalence, density, biomass and attachment sites of C. vesiculosum on planktonic microcrustaceans from Paiva Lake, a subtropical lake of Argentina. With the aim to evaluate whether epibionts affect the filtering rates of Notodiaptomus spiniger, the dominant planktonic crustacean, we carried out bioassays using phytoplankton <53µm. Crustaceans were sampled using a PVC tube (1.2m long and 10cm in diameter, filtering 50L of water through a 53µm-mesh. Microcrustaceans were counted in Bogorov chambers under a stereoscopic microscope. The infested organisms were separated and observed with a photonic microscope to determine density and biovolume of epibionts, by analyzing their distribution on the exoskeleton. The prevalence of C. vesiculosum was higher in adult crustaceans than in their larvae and juveniles. The most infested group was that of calanoid copepods, related to their high density. The attachment sites on the exoskeleton were found to be the portions of the body which have a higher probability of encounter with epibionts during locomotion and feeding, i.e., antennae and thoracic legs in copepods, and thoracic legs and postabdomen in cladocerans. The similar values found in the filtering rate of infested and uninfested individuals of N. spiniger and the constant prevalence (<40% of epibiont algae, suggest that C. vesiculosum does not condition the life of planktonic crustaceans of Paiva Lake. Rev. Biol. Trop. 59 (3: 1295-1306. Epub 2011 September 01.

Sensitivity of glaciation in the arid subtropical Andes to changes in temperature, precipitation, and solar radiation

Science.gov (United States)

Vargo, L. J.; Galewsky, J.; Rupper, S.; Ward, D. J.

2018-04-01

The subtropical Andes (18.5-27 °S) have been glaciated in the past, but are presently glacier-free. We use idealized model experiments to quantify glacier sensitivity to changes in climate in order to investigate the climatic drivers of past glaciations. We quantify the equilibrium line altitude (ELA) sensitivity (the change in ELA per change in climate) to temperature, precipitation, and shortwave radiation for three distinct climatic regions in the subtropical Andes. We find that in the western cordillera, where conditions are hyper-arid with the highest solar radiation on Earth, ELA sensitivity is as high as 34 m per % increase in precipitation, and 70 m per % decrease in shortwave radiation. This is compared with the eastern cordillera, where precipitation is the highest of the three regions, and ELA sensitivity is only 10 m per % increase in precipitation, and 25 m per % decrease in shortwave radiation. The high ELA sensitivity to shortwave radiation highlights the influence of radiation on mass balance of high elevation and low-latitude glaciers. We also consider these quantified ELA sensitivities in context of previously dated glacial deposits from the regions. Our results suggest that glaciation of the humid eastern cordillera was driven primarily by lower temperatures, while glaciations of the arid Altiplano and western cordillera were also influenced by increases in precipitation and decreases in shortwave radiation. Using paleoclimate records from the timing of glaciation, we find that glaciation of the hyper-arid western cordillera can be explained by precipitation increases of 90-160% (1.9-2.6× higher than modern), in conjunction with associated decreases in shortwave radiation of 7-12% and in temperature of 3.5 °C.

Biodiversity of frog haemoparasites from sub-tropical northern KwaZulu-Natal, South Africa

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Edward C. Netherlands

2015-04-01

Full Text Available Since South Africa boasts a high biodiversity of frog species, a multispecies haemoparasite survey was conducted by screening the blood from 29 species and 436 individual frogs. Frogs were collected at three localities in sub-tropical KwaZulu-Natal, a hotspot for frog diversity. Twenty per cent of the frogs were infected with at least one of five groups of parasites recorded. Intraerythrocytic parasites comprising Hepatozoon, Dactylosoma, and viral or bacterial organisms, as well as extracellular parasites including trypanosomes and microfilarid nematodes were found. A significant difference (P < 0.01 in the prevalence of parasitaemia was found across species, those semi-aquatic species demonstrating the highest, followed by semi-terrestrial frog species. None of those species described as purely terrestrial and aquatic were infected. Hepatozoon and Trypanosoma species accounted for most of the infections, the former demonstrating significant differences in intensity of infection across species, families and habitat types (P = 0.028; P = 0.006; P = 0.007 respectively. Per locality, the first, the formally protected Ndumo Game Reserve, had the highest biodiversity of haemoparasite infections, with all five groups of parasites recorded. The other two sites, that is the area bordering the reserve and the Kwa Nyamazane Conservancy, had a lower diversity with no parasite infections recorded and only Hepatozoon species recorded respectively. Such findings could be ascribed to the anthropogenic impact on the latter two sites, the first by the rural village activities, and the second by the bordering commercial sugar cane agriculture. Future studies should include both morphological and molecular descriptions of the above parasites, as well as the identification of potential vectors, possibly clarifying the effects human activities may have on frog haemoparasite life cycles and as such their biodiversity.

Underestimated effects of low temperature during early growing season on carbon sequestration of a subtropical coniferous plantation

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W.-J. Zhang

2011-06-01

Full Text Available The impact of air temperature in early growing season on the carbon sequestration of a subtropical coniferous plantation was discussed through analyzing the eddy flux observations at Qianyanzhou (QYZ site in southern China from 2003 to 2008. This site experienced two cold early growing seasons (with temperature anomalies of 2–5 °C in 2005 and 2008, and a severe summer drought in 2003.
Results indicated that the low air temperature from January to March was the major factor controlling the inter-annual variations in net carbon uptake at this site, rather than the previously thought summer drought. The accumulative air temperature from January to February showed high correlation (R²=0.970, p<0.001 with the annual net ecosystem production (NEP. This was due to the controls of early-month temperature on the plant phenology developing and the growing season length at this subtropical site. The cold spring greatly shortened the growing season length and therefore reduced the carbon uptake period. The eddy flux observations showed a carbon loss of 4.04 g C m⁻² per growing-season day at this coniferous forest site. On the other hand, the summer drought also reduced the net carbon uptake strength because the photosynthesis was more sensitive to water deficit stress than the ecosystem respiration. However, the impact of summer drought occurred within a relatively shorter period and the carbon sequestration went back to the normal level once the drought was relieved.

Comparisons between POC and zooplankton swimmer flux from sediment traps in the subarctic and subtropical North Pacific

Science.gov (United States)

Yokoi, Naoya; Abe, Yoshiyuki; Kitamura, Minoru; Honda, Makio C.; Yamaguchi, Atsushi

2018-03-01

Seasonal changes in zooplankton swimmer (ZS) abundance, biomass and community structure were evaluated based on samples collected by moored sediment traps at a depth of 200 m in the subarctic (SA) and subtropical (ST) western North Pacific. Based on these samples, we made comparisons on two topics: 1) latitudinal (subarctic vs. subtropical) changes in ZS abundance, biomass and community and 2) quantitative differences between the ZS and particle organic carbon (POC) fluxes based on data from moored or drifting sediment traps. The results showed that the ZS flux was greater in the SA (annual mean: 311 ind. m-2 day-1 or 258 mg C m-2 day-1) than in the ST (135 ind. m-2 day-1 or 38 mg C m-2 day-1). The peak ZS flux was observed from July-August in the SA and from April-May in the ST. The dominant taxa were Copepoda and Chaetognatha in the SA and Ostracoda and Mollusca in the ST. These latitudinal differences are likely related to the dominance of large-sized Copepoda in the SA, regional differences in the timing of the spring phytoplankton bloom, and the magnitude and size structure of primary producers. The percent composition of ZS to the total C flux (= ZS+POC flux) varied by region: 85-95% in the SA and 47-75% in the ST. These differences between the ZS composition and the total C flux are most likely caused by the dominance of large-sized Copepoda (Neocalanus spp. and Eucalanus bungii) in the SA.

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria.

Science.gov (United States)

Tonetta, D; Laudares-Silva, R; Petrucio, M M

2015-05-01

Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

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D. Tonetta

Full Text Available Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.

Analysis of the mixing processes in the subtropical Advancetown Lake, Australia

Science.gov (United States)

Bertone, Edoardo; Stewart, Rodney A.; Zhang, Hong; O'Halloran, Kelvin

2015-03-01

This paper presents an extensive investigation of the mixing processes occurring in the subtropical monomictic Advancetown Lake, which is the main water body supplying the Gold Coast City in Australia. Meteorological, chemical and physical data were collected from weather stations, laboratory analysis of grab samples and an in-situ Vertical Profiling System (VPS), for the period 2008-2012. This comprehensive, high frequency dataset was utilised to develop a one-dimensional model of the vertical transport and mixing processes occurring along the water column. Multivariate analysis revealed that air temperature and rain forecasts enabled a reliable prediction of the strength of the lake stratification. Vertical diffusion is the main process driving vertical mixing, particularly during winter circulation. However, a high reservoir volume and warm winters can limit the degree of winter mixing, causing only partial circulation to occur, as was the case in 2013. This research study provides a comprehensive approach for understanding and predicting mixing processes for similar lakes, whenever high-frequency data are available from VPS or other autonomous water monitoring systems.

Effects of land use change on soil gross nitrogen transformation rates in subtropical acid soils of Southwest China.

Science.gov (United States)

Xu, Yongbo; Xu, Zhihong

2015-07-01

Land use change affects soil gross nitrogen (N) transformations, but such information is particularly lacking under subtropical conditions. A study was carried out to investigate the potential gross N transformation rates in forest and agricultural (converted from the forest) soils in subtropical China. The simultaneously occurring gross N transformations in soil were quantified by a (15)N tracing study under aerobic conditions. The results showed that change of land use types substantially altered most gross N transformation rates. The gross ammonification and nitrification rates were significantly higher in the agricultural soils than in the forest soils, while the reverse was true for the gross N immobilization rates. The higher total carbon (C) concentrations and C / N ratio in the forest soils relative to the agricultural soils were related to the greater gross N immobilization rates in the forest soils. The lower gross ammonification combined with negligible gross nitrification rates, but much higher gross N immobilization rates in the forest soils than in the agricultural soils suggest that this may be a mechanism to effectively conserve available mineral N in the forest soils through increasing microbial biomass N, the relatively labile organic N. The greater gross nitrification rates and lower gross N immobilization rates in the agricultural soils suggest that conversion of forests to agricultural soils may exert more negative effects on the environment by N loss through NO3 (-) leaching or denitrification (when conditions for denitrification exist).

Effects of Spartina alterniflora invasion on biogenic elements in a subtropical coastal mangrove wetland.

Science.gov (United States)

Yu, Xiaoqing; Yang, Jun; Liu, Lemian; Tian, Yuan; Yu, Zheng

2015-02-01

The invasion by exotic cordgrass (Spartina alterniflora) has become one of the most serious and challenging environmental and ecological problems in coastal China because it can have adverse effects on local native species, thereby changing ecosystem processes, functions, and services. In this study, 300 surface sediments were collected from 15 stations in the Jiulong River Estuary, southeast China, across four different seasons, in order to reveal the spatiotemporal variability of biogenic elements and their influencing factors in the subtropical coastal mangrove wetland. The biogenic elements including carbon, nitrogen, and sulfur (C, N, and S) were determined by an element analyzer, while the phosphorus (P) was determined by a flow injection analyzer. The concentrations of biogenic elements showed no significant differences among four seasons except total phosphorus (TP); however, our ANOVA analyses revealed a distinct spatial pattern which was closely related with the vegetation type and tidal level. Values of total carbon (TC) and total nitrogen (TN) in the surface sediment of mangrove vegetation zones were higher than those in the cordgrass and mudflat zones. The concentrations of TC, TN, TP, and total sulfur (TS) in the high tidal zones were higher than those in the middle and low tidal zones. Redundancy analysis (RDA) revealed that tidal level, vegetation type, and season had some significant influence on the distribution of biogenic elements in the Jiulong River Estuary, by explaining 18.2, 7.7, and 4.9 % of total variation in the four biogenic elements, respectively. In conclusion, S. alterniflora invasion had substantial effects on the distributions of biogenic elements in the subtropical coastal wetland. If regional changes in the Jiulong River Estuary are to persist and much of the mangrove vegetation was to be replaced by cordgrass, there would be significant decreases on the overall storage of C and N in this coastal zone. Therefore, the native

Reconstructing vegetation past: Pre-Euro-American vegetation for the midwest driftless area, USA

Science.gov (United States)

Monika E. Shea; Lisa A. Schulte; Brian J. Palik

2014-01-01

Historical reference conditions provide important context for creating ecological restoration and management plans. The U.S. 19th Century Public Land Survey (PLS) records provide extensive ecological information for constructing such reference conditions. We used PLS records to reconstruct pre-Euro-American tree species cover class and vegetation structure types for...

The winter diet of elephant in Eastern Cape Subtropical Thicket, Addo Elephant National Park

Directory of Open Access Journals (Sweden)

R.G.T. Paley

1998-07-01

Full Text Available Direct observational methods were used to establish the winter diet of elephants in Eastern Cape Subtropical Thicket in the Addo Elephant National Park, thereby determining which plant species were most at risk from elephant herbivory. A total of 70 species were identified as food plants for elephants, with the grass Cynodon dactylon and the succulents Portulacaria afra and Platythyra haeckeliana dominating, both in terms of frequency of feeding events and volume consumed. In view of the fact that elephants represent 78 of the herbivore biomass in the park, it appears likely that elephant feeding restricts the availability of forage for other browsers. Due to the limited time frame of this study, further research is needed to provide a comprehensive record of the elephant diet for all seasons of the year.

Phylogenetic congruence between subtropical trees and their associated fungi.

Science.gov (United States)

Liu, Xubing; Liang, Minxia; Etienne, Rampal S; Gilbert, Gregory S; Yu, Shixiao

2016-12-01

Recent studies have detected phylogenetic signals in pathogen-host networks for both soil-borne and leaf-infecting fungi, suggesting that pathogenic fungi may track or coevolve with their preferred hosts. However, a phylogenetically concordant relationship between multiple hosts and multiple fungi in has rarely been investigated. Using next-generation high-throughput DNA sequencing techniques, we analyzed fungal taxa associated with diseased leaves, rotten seeds, and infected seedlings of subtropical trees. We compared the topologies of the phylogenetic trees of the soil and foliar fungi based on the internal transcribed spacer (ITS) region with the phylogeny of host tree species based on matK , rbcL , atpB, and 5.8S genes. We identified 37 foliar and 103 soil pathogenic fungi belonging to the Ascomycota and Basidiomycota phyla and detected significantly nonrandom host-fungus combinations, which clustered on both the fungus phylogeny and the host phylogeny. The explicit evidence of congruent phylogenies between tree hosts and their potential fungal pathogens suggests either diffuse coevolution among the plant-fungal interaction networks or that the distribution of fungal species tracked spatially associated hosts with phylogenetically conserved traits and habitat preferences. Phylogenetic conservatism in plant-fungal interactions within a local community promotes host and parasite specificity, which is integral to the important role of fungi in promoting species coexistence and maintaining biodiversity of forest communities.

Phytoplankton community structure at the juncture of the Agulhas return front and subtropical front in the Indian Ocean sector of Southern Ocean: Bottom-up and top-down control

Digital Repository Service at National Institute of Oceanography (India)

Naik, R.K.; George, J.V.; Soares, M.A.; Devi, A.; Anilkumar, N.; Roy, R.; Bhaskar, P.V.; Murukesh, N.; Achuthankutty, C.T.

The juncture of the Agulhas Return Front (ARF) and Subtropical Front (STF) in the Indian Ocean sector of Southern Ocean (SO) is characterized by high mesoscale turbulence, which results in sporadic, short lived phytoplankton proliferation The biota...

Characteristics and Mechanisms of Zonal Oscillation of Western Pacific Subtropical High in Summer

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Guan, W.; Ren, X.; Hu, H.

2017-12-01

The zonal oscillation of the western Pacific subtropical high (WPSH) influences the weather and climate over East Asia significantly. This study investigates the features and mechanisms of the zonal oscillation of the WPSH during summer on subseasonal time scales. The zonal oscillation index of the WPSH is defined by normalized subseasonal geopotential height anomaly at 500hPa averaged over the WPSH's western edge (110° - 140°E, 10° - 30°N). The index shows a predominant oscillation with a period of 10-40 days. Large positive index indicates a strong anticyclonic anomaly over East Asia and its coastal region south of 30°N at both 850hPa and 500hPa. The WPSH stretches more westward accompanied by warmer SST anomalies beneath the western edge of the WPSH. Meanwhile, above-normal precipitation is seen over the Yangtze-Huaihe river basin and below-normal precipitation over the south of the Yangtze River. Negative index suggests a more eastward position of WPSH. The anomalies in circulation and SST for negative index are almost the mirror image of those for the positive index. In early summer, the zonal shift of the WPSH is affected by both the East Asia/Pacific (EAP) teleconnection pattern and the Silk road pattern (SRP). The positive (negative) phase of the EAP pattern is characterized by a low-level anticyclonic (cyclonic) anomaly over the subtropical western Pacific, indicating the western extension (eastward retreat) of the WPSH. Comparing with the EAP pattern, the SRP forms an upper-level anticyclonic (cyclonic) anomaly in mid-latitudes of East Asia, and then leads to the westward (eastward) movement of the WPSH. In late summer, the zonal shift of the WPSH is mainly affected by the EAP pattern, because the EAP pattern in late summer is stronger than that in early summer. The zonal shift of the WPSH is also influenced by the subseasonal air-sea interaction locally. During the early stage of WPSH's westward stretch, the local SST anomaly in late summer is

Change in Intra-Abdominal Fat Predicts the Risk of Hypertension in Japanese Americans.

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Sullivan, Catherine A; Kahn, Steven E; Fujimoto, Wilfred Y; Hayashi, Tomoshige; Leonetti, Donna L; Boyko, Edward J

2015-07-01

In Japanese Americans, intra-abdominal fat area measured by computed tomography is positively associated with the prevalence and incidence of hypertension. Evidence in other populations suggests that other fat areas may be protective. We sought to determine whether a change in specific fat depots predicts the development of hypertension. We prospectively followed up 286 subjects (mean age, 49.5 years; 50.4% men) from the Japanese American Community Diabetes Study for 10 years. At baseline, subjects did not have hypertension (defined as blood pressure ≥140/90 mm Hg) and were not taking blood pressure or glucose-lowering medications. Mid-thigh subcutaneous fat area, abdominal subcutaneous fat area, and intra-abdominal fat area were directly measured by computed tomography at baseline and 5 years. Logistic regression was used to estimate odds of incident hypertension over 10 years in relation to a 5-year change in fat area. The relative odds of developing hypertension for a 5-year increase in intra-abdominal fat was 1.74 (95% confidence interval, 1.28-2.37), after adjusting for age, sex, body mass index, baseline intra-abdominal fat, alcohol use, smoking status, and weekly exercise energy expenditure. This relationship remained significant when adjusted for baseline fasting insulin and 2-hour glucose levels or for diabetes mellitus and pre-diabetes mellitus classification. There were no significant associations between baseline and change in thigh or abdominal subcutaneous fat areas and incident hypertension. In conclusion, in this cohort of Japanese Americans, the risk of developing hypertension is related to the accumulation of intra-abdominal fat rather than the accrual of subcutaneous fat in either the thigh or the abdominal areas. © 2015 American Heart Association, Inc.

Help-Seeking Experiences and Attitudes among African American, Asian American, and European American College Students

Science.gov (United States)

Masuda, Akihiko; Anderson, Page L.; Twohig, Michael P.; Feinstein, Amanda B.; Chou, Ying-Yi; Wendell, Johanna W.; Stormo, Analia R.

2009-01-01

The study examined African American, Asian American, and European American college students' previous direct and indirect experiences of seeking professional psychological services and related attitudes. Survey data were collected from 254 European American, 182 African American and 82 Asian American college students. Results revealed that fewer…

Latin American cooperation on nuclear energy

International Nuclear Information System (INIS)

Faria, N.M. de; Associacao Brasileira de Direito Nuclear, Rio de Janeiro)

1984-01-01

The cooperation between Latin American countries on nuclear matters in which Brazil should play a significant role is presented. The possible areas for cooperation, particularly the nuclear law, are focused. The cooperation should be developed on bilateral or multilateral basis, by governmental and non governmental entities. (Author) [pt

Contribution of aerobic anoxygenic phototrophic bacteria to total organic carbon pool in aquatic system of subtropical karst catchments, Southwest China: evidence from hydrochemical and microbiological study.

Science.gov (United States)

Li, Qiang; Song, Ang; Peng, Wenjie; Jin, Zhenjiang; Müller, Werner E G; Wang, Xiaohong

2017-06-01

Aerobic anoxygenic phototrophic bacteria may play a particular role in carbon cycling of aquatic systems. However, little is known about the interaction between aerobic anoxygenic phototrophic bacteria and hydrochemistry in groundwater-surface water exchange systems of subtropical karst catchments. We carried out a detailed study on the abundance of aerobic anoxygenic phototrophic bacteria and bacterioplankton, hydrochemistry and taxonomy of bacterioplankton in the Maocun watershed, Southwest China, an area with karst geological background. Our results revealed that bacteria are the important contributors to total organic carbon source/sequestration in the groundwater-surface water of this area. The aerobic anoxygenic phototrophic bacteria, including β-Proteobacteria, also appear in the studied water system. In addition to that, the genus Polynucleobacter of the phototropic β-Proteobacteria shows a close link with those sampling sites by presenting bacterial origin organic carbon on CCA biplot and is found to be positively correlated with total nitrogen, dissolved oxygen and pH (r = 0.860, 0.747 and 0.813, respectively) in the Maocun watershed. The results suggest that Polynucleobacter might be involved in the production of organic carbon and might act as the negative feedback on global warming. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

American Samoa Initial Technical Assessment Report

Energy Technology Data Exchange (ETDEWEB)

Busche, S.; Conrad, M.; Funk, K.; Kandt, A.; McNutt, P.

2011-09-01

This document is an initial energy assessment for American Samoa, the first of many steps in developing a comprehensive energy strategy. On March 1, 2010, Assistant Secretary of the Interior Tony Babauta invited governors and their staff from the Interior Insular Areas to meet with senior principals at the National Renewable Energy Laboratory (NREL). Meeting discussions focused on ways to improve energy efficiency and increase the deployment of renewable energy technologies in the U.S. Pacific Territories. In attendance were Governors Felix Camacho (Guam), Benigno Fitial (Commonwealth of the Northern Mariana Islands), and Togiola Tulafono, (American Samoa). This meeting brought together major stakeholders to learn and understand the importance of developing a comprehensive strategic plan for implementing energy efficiency measures and renewable energy technologies. For several decades, dependence on fossil fuels and the burden of high oil prices have been a major concern but never more at the forefront as today. With unstable oil prices, the volatility of fuel supply and the economic instability in American Samoa, energy issues are a high priority. In short, energy security is critical to American Samoa's future economic development and sustainability. Under an interagency agreement, funded by the Department of Interior's Office of Insular Affairs, NREL was tasked to deliver technical assistance to the islands of American Samoa. Technical assistance included conducting an initial technical assessment to define energy consumption and production data, establish an energy consumption baseline, and assist with the development of a strategic plan. The assessment and strategic plan will be used to assist with the transition to a cleaner energy economy. NREL provided an interdisciplinary team to cover each relevant technical area for the initial energy assessments. Experts in the following disciplines traveled to American Samoa for on-island site assessments: (1

A Mexican American Woman Encounters Sociology: An Autobiographical Perspective.

Science.gov (United States)

Williams, Norma

1988-01-01

Describes the author's experience of teaching bilingual educators. Identifies the bureaucratic structure of the school and the Mexican American culture as the two problem areas focused upon during the course. Concludes that her major areas of research interest in sociology are a direct product of her ethnicity, work experience, and this…

Crop Response to Gypsum Application to Subtropical Soils Under No-Till in Brazil: a Systematic Review

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Tales Tiecher

2018-02-01

Full Text Available ABSTRACT The use of gypsum to improve the root environment in tropical soils in the southeastern and central-western regions of Brazil is a widespread practice with well-established recommendation criteria. However, only recently gypsum began to be used on subtropical soils in South of Brazil, so available knowledge of its effect on crop yield is incipient and mainly for soils under no-till (NT systems. Avaiable studies span a wide range of responses, from a substantial increase to a slight reduction in crop yield. Also, the specific conditions leading to a favorable effect of gypsum application on crop yield are yet to be accurately identified. The primary objectives of this study were to examine previously reported results to assess the likelihood of a crop response to gypsum and to develop useful recommendation criteria for gypsum application to subtropical soils under NT in Brazil. For this purpose, we examined the results of a total of 73 growing seasons, reported in 20 different scientific publications that assessed grain yield as a function of gypsum rates. Four different scenarios were examined, by the occurrence or not of high subsurface acidity (viz., Al saturation >20 % and/or exchangeable Ca 3 cmolc dm-3 failed to increase crop yield, irrespective of the soil water status. Under these conditions, high gypsum rates (6-15 Mg ha−1 may even reduce grain yield, possibly by inducing K and Mg deficiency. On the other hand, applying gypsum to soils with high subsurface acidity increased yield by 16 % in corn (87 % of cases and by 19 % in winter cereals (83 % of cases, whether or not the soil was water-deficient. By contrast, soybean yield was only increased by gypsum applied in the simultaneous presence of high soil subsurface acidity and water deficiency (average increase 27 %, 100 % of cases.

Changes in the influence of the western Pacific subtropical high on Asian summer monsoon rainfall in the late 1990s

Science.gov (United States)

Huang, Yanyan; Wang, Bin; Li, Xiaofan; Wang, Huijun

2017-10-01

The Year-to-year variability of the western Pacific subtropical high (WPSH) is primarily controlled by atmosphere-ocean interaction (AOI) between the WPSH and the Indo-Pacific warm pool dipole SST anomalies (AOI mode) and the anomalous SST forcing from the equatorial central Pacific (the CP forcing mode). In this study, we show that the impacts of the WPSH variability on Asian summer monsoon rainfall have changed after the late 1990s. Before the late 1990s (the PRE epoch), the WPSH primarily affects East Asian summer monsoon (EASM) and had little influence on Indian summer monsoon (ISM), whereas after the late 1990s (the POST epoch), the WPSH has strengthened its linkage to the ISM while weakened its relationship with the EASM. This epochal change is associated with a change in the leading circulation mode in the Asia-WP region. During the PRE (POST) epoch the WPSH variation is mainly controlled by the AOI (CP forcing) that mainly affects EASM (ISM). The epochal change of the leading mode may be attributed to the change of the ENSO properties in late 1990s: the CP types of El Nino become a leading ENSO mode in the POST epoch. This work provides a new perspective for understanding decadal changes of the ENSO-monsoon relationship through subtropical dynamics.

Interrelated variations of O3, CO and deep convection in the tropical/subtropical upper troposphere observed by the Aura Microwave Limb Sounder (MLS during 2004–2011

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L. Froidevaux

2013-01-01

Full Text Available The interrelated geographic and temporal variability seen in more than seven years of tropical and subtropical upper tropospheric (215 hPa ozone, carbon monoxide and cloud ice water content (IWC observations by the Aura Microwave Limb Sounder (MLS are presented. Observed ozone abundances and their variability (geographic and temporal agree to within 10–15 ppbv with records from sonde observations. MLS complements these (and other observations with global coverage and simultaneous measurements of related parameters. Previously-reported phenomena such as the ozone "wave one" feature are clearly seen in the MLS observations, as is a double peak in ozone abundance over tropical East Africa, with enhanced abundances in both May to June and September to November. While repeatable seasonal cycles are seen in many regions, they are often accompanied by significant interannual variability. Ozone seasonal cycles in the southern tropics and subtropics tend to be more distinct (i.e., annually repeatable than in the northern. By contrast, carbon monoxide shows distinct seasonal cycles in many northern subtropical regions, notably from India to the Eastern Pacific. Deep convection (as indicated by large values of IWC is typically associated with reductions in upper tropospheric ozone. Convection over polluted regions is seen to significantly enhance upper tropospheric carbon monoxide. While some regions show statistically significant correlations among ozone, carbon monoxide and IWC, simple correlations fall well short of accounting for the observed variability. The observed interrelated variations and metrics of annual and interannual variability described here represent a new resource for validation of atmospheric chemistry models.

Soil organic carbon stock and distribution in cultivated land converted to grassland in a subtropical region of China.

Science.gov (United States)

Zhang, J H; Li, F C; Wang, Y; Xiong, D H

2014-02-01

Land-use change from one type to another affects soil carbon (C) stocks which is associated with fluxes of CO2 to the atmosphere. The 10-years converted land selected from previously cultivated land in hilly areas of Sichuan, China was studied to understand the effects of land-use conversion on soil organic casrbon (SOC) sequestration under landscape position influences in a subtropical region of China. The SOC concentrations of the surface soil were greater (P\\0.001) for converted soils than those for cultivated soils but lower (P\\0.001) than those for original uncultivated soils. The SOC inventories (1.90–1.95 kg m-2) in the 0–15 cm surface soils were similar among upper, middle, and lower slope positions on the converted land, while the SOC inventories (1.41–1.65 kg m-2) in this soil layer tended to increase from upper to lower slope positions on the cultivated slope. On the whole, SOC inventories in this soil layer significantly increased following the conversion from cultivated land to grassland (P\\0.001). In the upper slope positions, converted soils (especially in 0–5 cm surface soil) exhibited a higher C/N ratio than cultivated soils (P = 0.012), implying that strong SOC sequestration characteristics exist in upper slope areas where severe soil erosion occurred before land conversion. It is suggested that landscape position impacts on the SOC spatial distribution become insignificant after the conversion of cultivated land to grassland, which is conducive to the immobilization of organic C. We speculate that the conversion of cultivated land to grassland would markedly increase SOC stocks in soil and would especially improve the potential for SOC sequestration in the surface soil over a moderate period of time (10 years).

Renewable energy plan of action for American Samoa

Energy Technology Data Exchange (ETDEWEB)

Shupe, J.W. (USDOE San Francisco Operations Office, Honolulu, HI (USA). Pacific Site Office); Stevens, J.W. (Sandia National Labs., Albuquerque, NM (USA))

1990-11-01

American Samoa has no indigenous fossil fuels and is almost totally dependent for energy on seaborne petroleum. However, the seven Pacific Islands located at 14 degrees south latitude that constitute American Samoa have a wide variety of renewable resources with the potential for substituting for imported oil. Included as possible renewable energy conversion technologies are solar thermal, photovoltaics, wind, geothermal, ocean thermal, and waste-to-energy recovery. This report evaluates the potential of each of these renewable energy alternatives and establishes recommended priorities for their development in American Samoa. Rough cost estimates are also included. Although renewable energy planning is highly site specific, information in this report should find some general application to other tropical insular areas.

Integrated fossil and molecular data reveal the biogeographic diversification of the eastern Asian-eastern North American disjunct hickory genus (Carya Nutt.).

Science.gov (United States)

Zhang, Jing-Bo; Li, Rui-Qi; Xiang, Xiao-Guo; Manchester, Steven R; Lin, Li; Wang, Wei; Wen, Jun; Chen, Zhi-Duan

2013-01-01

The hickory genus (Carya) contains ca. 17 species distributed in subtropical and tropical regions of eastern Asia and subtropical to temperate regions of eastern North America. Previously, the phylogenetic relationships between eastern Asian and eastern North American species of Carya were not fully confirmed even with an extensive sampling, biogeographic and diversification patterns had thus never been investigated in a phylogenetic context. We sampled 17 species of Carya and 15 species representing all other genera of the Juglandaceae as outgroups, with eight nuclear and plastid loci to reconstruct the phylogeny of Carya. The phylogenetic positions of seven extinct genera of the Juglandaceae were inferred using morphological characters and the molecular phylogeny as a backbone constraint. Divergence times within Carya were estimated with relaxed Bayesian dating. Biogeographic analyses were performed in DIVA and LAGRANGE. Diversification rates were inferred by LASER and APE packages. Our results support two major clades within Carya, corresponding to the lineages of eastern Asia and eastern North America. The split between the two disjunct clades is estimated to be 21.58 (95% HPD 11.07-35.51) Ma. Genus-level DIVA and LAGRANGE analyses incorporating both extant and extinct genera of the Juglandaceae suggested that Carya originated in North America, and migrated to Eurasia during the early Tertiary via the North Atlantic land bridge. Fragmentation of the distribution caused by global cooling in the late Tertiary resulted in the current disjunction. The diversification rate of hickories in eastern North America appeared to be higher than that in eastern Asia, which is ascribed to greater ecological opportunities, key morphological innovations, and polyploidy.

Integrated fossil and molecular data reveal the biogeographic diversification of the eastern Asian-eastern North American disjunct hickory genus (Carya Nutt..

Directory of Open Access Journals (Sweden)

Jing-Bo Zhang

Full Text Available The hickory genus (Carya contains ca. 17 species distributed in subtropical and tropical regions of eastern Asia and subtropical to temperate regions of eastern North America. Previously, the phylogenetic relationships between eastern Asian and eastern North American species of Carya were not fully confirmed even with an extensive sampling, biogeographic and diversification patterns had thus never been investigated in a phylogenetic context. We sampled 17 species of Carya and 15 species representing all other genera of the Juglandaceae as outgroups, with eight nuclear and plastid loci to reconstruct the phylogeny of Carya. The phylogenetic positions of seven extinct genera of the Juglandaceae were inferred using morphological characters and the molecular phylogeny as a backbone constraint. Divergence times within Carya were estimated with relaxed Bayesian dating. Biogeographic analyses were performed in DIVA and LAGRANGE. Diversification rates were inferred by LASER and APE packages. Our results support two major clades within Carya, corresponding to the lineages of eastern Asia and eastern North America. The split between the two disjunct clades is estimated to be 21.58 (95% HPD 11.07-35.51 Ma. Genus-level DIVA and LAGRANGE analyses incorporating both extant and extinct genera of the Juglandaceae suggested that Carya originated in North America, and migrated to Eurasia during the early Tertiary via the North Atlantic land bridge. Fragmentation of the distribution caused by global cooling in the late Tertiary resulted in the current disjunction. The diversification rate of hickories in eastern North America appeared to be higher than that in eastern Asia, which is ascribed to greater ecological opportunities, key morphological innovations, and polyploidy.

Native American Arts and Crafts of the United States. Bibliography 1.

Science.gov (United States)

Indian Arts and Crafts Board, Washington, DC.

The selected readings listed in this annotated bibliography are suggested as an introduction to the varied arts and crafts created from prehistoric to modern times by Native American peoples of the United States. The publications are organized by culture area to encompass major media practiced by Native American artists and craftsmen of these…

Weathering on land and transport of chromium to the ocean in a subtropical region (Misiones, NW Argentina)

DEFF Research Database (Denmark)

Frei, Robert; Poiré, Daniel G.; Frei, Karin Margarita

2014-01-01

We have investigated the pathway of chromium from its mobilization on land and along its riverine transport in a subtropical region of South America (Misiones Province, Argentina), in an attempt to link Cr stable isotope compositions recently measured in seawater with signals prevailing in rivers......; this is essentially due to the affinity of REE and U, but not Cr with secondary phosphates which form during weathering processes. Smaller tributaries in NW Argentina to the Paraná River (second largest river in South America) carry dissolved Cr in the order of 0.7–1.4 ppb (13–27 nM) with δ53Cr values of + 0.2 to + 0...

Using eddy geopotential height to measure the western North Pacific subtropical high in a warming climate

Science.gov (United States)

He, Chao; Lin, Ailan; Gu, Dejun; Li, Chunhui; Zheng, Bin; Wu, Bo; Zhou, Tianjun

2018-01-01

The western North Pacific subtropical high (WNPSH) is crucial to the East Asian summer climate, and geopotential height ( H) is widely used to measure the WPNSH. However, a rapidly rising trend of H in the future is projected by the models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Diagnoses based on the hypsometric equation suggest that more than 80% of the rise in H are attributable to zonal uniform warming. Because circulation is determined by the gradient of H rather than its absolute magnitude, the spatially uniform rising trend of H gives rise to difficulties when measuring the WNPSH with H. These difficulties include an invalid western boundary of WNPSH in the future and spurious information regarding long-term trends and interannual variability of WNPSH. Using CMIP5 model simulations and reanalysis data, the applicability of a metric based on eddy geopotential height ( H e ) to the warming climate is investigated. The results show that the H e metric outperforms the H metric under warming climate conditions. First, the mean state rainfall- H e relationship is more robust than the rainfall- H relationship. Second, the area, intensity, and western boundary indices of WNPSH can be effectively defined by the H e = 0-m contour in future warming climate scenarios without spurious trends. Third, the interannual variability of East Asian summer rainfall is more closely related to the H e -based WNPSH indices. We recommend that the H e metric be adopted as an operational metric on the WNPSH under the current warming climate.

Susceptibility of a North American Culex quinquefasciatus to Japanese encephalitis virus

Science.gov (United States)

Japanese encephalitis virus (JEV) is a flavivirus that is transmitted by Culex (Cx.) tritaeniorhynchus in tropical and subtropical regions of Asia. The endemic transmission cycle involves domestic pigs and avian species that serve as amplification hosts; humans are incidental hosts that cannot devel...

Proceedings of the Latin American School of Physics

International Nuclear Information System (INIS)

1991-01-01

The main subjects covered by the Latin American School of Physics are nuclear physics and elementary particle physics. Some areas such as solid state physics, statistical mechanics and gravitation are also included. (M.C.K.)

Molecular phylogenetic analysis of the Persea group (Lauraceae) and its biogeographic implications on the evolution of tropical and subtropical Amphi-Pacific disjunctions.

Science.gov (United States)

Li, Lang; Li, Jie; Rohwer, Jens G; van der Werff, Henk; Wang, Zhi-Hua; Li, Hsi-Wen

2011-09-01

The Persea group (Lauraceae) has a tropical and subtropical amphi-pacific disjunct distribution with most of its members, and it includes two Macaronesian species. The relationships within the group are still controversial, and its intercontinental disjunction has not been investigated with extensive sampling and precise time dating. • ITS and LEAFY intron II sequences of 78 Persea group species and nine other Lauraceae species were analyzed with maximum parsimony and Bayesian inference. Divergence time estimation employed Bayesian Markov chain Monte Carlo method under a relaxed clock. • Several traditional genera or subgenera within the Persea group form well-supported monophyletic groups except Alseodaphne and Dehaasia. The divergence time of the Persea group is estimated as ∼55.3 (95% higher posterior densities [HPD] 41.4-69.9) million years ago (mya). Two major divergences within the Persea group are estimated as ∼51.9 (95% HPD 38.9-63.9) mya and ∼48.5 (95% HPD 35.9-59.9) mya. • Persea can be retained as a genus by the inclusion of Apollonias barbujana and exclusion a few species that do not fit into the established subgenera. A major revision is recommended for the delimitation between Alseodaphne, Dehaasia, and Nothaphoebe. We suggest that the Persea group originated from the Perseeae-Laureae radiation in early Eocene Laurasia. Its amphi-pacific disjunction results from the disruption of boreotropical flora by climatic cooling during the mid- to late Eocene. The American-Macaronesian disjunction may be explained by the long-distance dispersal.

Monitoring hymenoptera and diptera pollinators in a sub-tropical forest of southern punjab, pakistan

International Nuclear Information System (INIS)

Bashir, M.; Sajjad, A.

2013-01-01

Bees (Hymenoptera) and flies (Diptera) play an essential role in natural and agricultural ecosystems as pollinators of flowering plants while pollinators are declining around the world. Colored pan traps and Malaise traps have widely been used for monitoring pollinators. However, their efficiencies may vary with landscapes and type of fauna in a particular habitat. A yearlong study was carried out during 2009 to investigate the relative efficacy of colored pan traps and Malaise traps towards sampling flies and bees for the first time in a sub-tropical wildlife sanctuary Pirowal of Southern Punjab, Pakistan. Fifteen pan traps (5 each of 3 colors i.e. white, red and blue) were deployed against one Malaise trap for 7 hours (9:00-16:00 hrs) on fortnightly basis. For the comparison and confirmation of an insect as a floral visitor, collection with the hand net was also performed. It was concluded that hand net collection is essential to have a comprehensive list of floral visitors of an area as the maximum number (63) of species and their abundance (5428 individuals) were recorded with it. Malaise trap collected only 671 individuals of 48 species. Although blue, yellow and white pan traps caught 46, 51 and 35 species but the numbers of individuals (1383) were fairly higher than that of Malaise traps. Keeping in view the cost effectiveness and better performance of colored pan traps, we recommend species specific pan trap colors when targeting certain groups or species, nevertheless variety of pan colors should be used when sampling overall biodiversity. We generalize these findings for both bees and flies due to similar collection pattern i.e. the maximum abundance and diversity in hand net method followed by pan traps and Malaise traps. (author)

Monitoring Temporal Variation to Assess Changes in the Structure of Subtropical Atlantic Forest Butterfly Communities.

Science.gov (United States)

Iserhard, Cristiano Agra; Romanowski, Helena Piccoli; Richter, Aline; Mendonça, Milton de Souza

2017-08-01

The study of fauna through long-term surveys is important in unveiling how temporal patterns shape the structure of communities in tropical habitats. The butterfly assemblage of the subtropical Atlantic Forest may be considered highly diverse and shows changes in diversity and composition over time, highlighting the importance of long-term inventories. This work assessed temporal diversity patterns in the distribution and composition of butterfly assemblages in an Atlantic Forest site in southern Brazil using combined data from three years of standardized sampling with entomological nets, increasing the knowledge on this group in the Neotropics for monitoring and conservation. The butterfly fauna was analyzed in terms of richness, abundance, and composition. The inventories reached 401 species, with 14,442 butterfly individuals sampled. All the diversity parameters evaluated show significant differences between the first year of sampling compared to the second and third years. The latter had higher values of richness and abundance, followed by the first and second years. Hesperiidae was the richest family, followed by Nymphalidae and Lycaenidae, indicating a good representation of the assemblage as a whole. The results of this work are important for developing conservation programs in the Atlantic Forest and other forested environments in the neotropics, especially concerning reliable diversity assessments for the monitoring and management of protected areas. Decision making and public policy might also benefit from knowledge on temporal patterns of diversity regarding the maintenance of native habitats and integrity of biomes and their associated fauna. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Phylogenetic turnover during subtropical forest succession across environmental and phylogenetic scales.

Science.gov (United States)

Purschke, Oliver; Michalski, Stefan G; Bruelheide, Helge; Durka, Walter

2017-12-01

Although spatial and temporal patterns of phylogenetic community structure during succession are inherently interlinked and assembly processes vary with environmental and phylogenetic scales, successional studies of community assembly have yet to integrate spatial and temporal components of community structure, while accounting for scaling issues. To gain insight into the processes that generate biodiversity after disturbance, we combine analyses of spatial and temporal phylogenetic turnover across phylogenetic scales, accounting for covariation with environmental differences. We compared phylogenetic turnover, at the species- and individual-level, within and between five successional stages, representing woody plant communities in a subtropical forest chronosequence. We decomposed turnover at different phylogenetic depths and assessed its covariation with between-plot abiotic differences. Phylogenetic turnover between stages was low relative to species turnover and was not explained by abiotic differences. However, within the late-successional stages, there was high presence-/absence-based turnover (clustering) that occurred deep in the phylogeny and covaried with environmental differentiation. Our results support a deterministic model of community assembly where (i) phylogenetic composition is constrained through successional time, but (ii) toward late succession, species sorting into preferred habitats according to niche traits that are conserved deep in phylogeny, becomes increasingly important.

Plankton community dynamics in a subtropical lagoonal system and related factors

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LETÍCIA DONADEL

2016-03-01

Full Text Available ABSTRACT Changes of the plankton community in a shallow, subtropical lagoonal system and its relation to environmental conditions were investigated during an annual cycle to provide information on its spatial and seasonal variation pattern. The study carried out at four sites (three in the Peixe lagoon and one in the Ruivo lagoon, which are located in the Lagoa do Peixe National Park, southern Brazil. The system has a temporary connection to the Atlantic Ocean by a narrow channel. The phytoplankton density was higher in the Peixe lagoon whereas the specific richness was higher in the Ruivo lagoon which is also a site with the lower salinity. The phytoplankton biomass near the channel showed seasonal variation with the highest value in fall and lowest in winter. Zooplankton richness was inversely correlated with salinity, and had the highest values in the Ruivo lagoon. Ordination analysis indicated seasonal and spatial patterns in plankton community in this lagoonal system, related to variation in salinity. In addition, the wind action and precipitation were important factors on the spatial and seasonal salinity changes in the lagoon with direct influence on the plankton community dynamics.

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove.

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Sousa, Mariana M DE; Colpo, Karine D

2017-01-01

It is not unusual to find epiphytic bromeliads in mangroves, but most studies on mangrove vegetation do not record their presence. This study aimed to evaluate the diversity and distribution of epiphytic bromeliads in a subtropical mangrove. The richness, abundance and life form (atmospheric and tank) of bromeliads were recorded and compared among host tree species and waterline proximity. The effects of diameter and height of host trees on the abundance of bromeliads were also assessed. The mangrove was composed of Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. We recorded seven bromeliad species of the genera Tillandsia and Vriesea. The waterline proximity did not affect the abundance or diversity of bromeliads, but atmospheric forms were predominant near the waterline, whereas tank bromeliads were more frequent in the interior of the mangrove. The three mangrove species hosted bromeliads, but L. racemosa was the preferred host. The species composition showed that the distribution of bromeliads is more related to the host species than to the distance from the waterline. Bromeliad abundance increased with tree size. Bromeliads can be biological indicators of ecosystem health; therefore, inventories and host tree preferences are necessary knowledge for an adequate management of sensitive ecosystems as mangroves.

47 CFR 27.1208 - BTA service areas.

Science.gov (United States)

2010-10-01

.... Except for incumbent BRS licenses, BRS service areas are Basic Trading Areas (BTAs) or additional service... in places where Rand McNally has not defined BTAs: American Samoa; Guam; Gulf of Mexico Zone A; Gulf of Mexico Zone B; Gulf of Mexico Zone C; Northern Mariana Islands; Mayaguez/Aguadilla-Ponce, Puerto...

White-faced storm-petrels Pelagodroma marina predated by gulls as biological monitors of plastic pollution in the pelagic subtropical northeast atlantic

OpenAIRE

Furtado, Ricardo Miranda; Menezes, Dilia; Santos, Carolina Jardim; Catry, Paulo

2016-01-01

Marine plastic pollution is rapidly growing and is a source of major concern. Seabirds often ingest plastic debris and are increasingly used as biological monitors of plastic pollution. However, virtually no studies have assessed plastics in seabirds in the deep subtropical North Atlantic. We investigated whether remains of white-faced storm-petrels (WFSP) present in gull pellets could be used for biomonitoring. We analysed 263 pellets and 79.0% of these contained plastic debris originating i...

Energy conservation measures in an institutional building in sub-tropical climate in Australia

International Nuclear Information System (INIS)

Rahman, M.M.; Rasul, M.G.; Khan, M.M.K.

2010-01-01

In this study, various energy conservation measures (ECMs) on heating, ventilating and air conditioning (HVAC) and lighting systems for a four-storied institutional building in sub-tropical (hot and humid climate) Queensland, Australia are evaluated using the simulation software called DesignBuilder (DB). Base case scenario of energy consumption profiles of existing systems are analysed and simulated first then, the simulated results are verified by on-site measured data. Three categories of ECMs, namely major investment ECMs (variable air volume (VAV) systems against constant air volume (CAV); and low coefficient of performance (COP) chillers against high COP chillers); minor investment ECMs (photo electric dimming control system against general lighting, and double glazed low emittance windows against single-glazed windows) and zero investment ECMs (reset heating and cooling set point temperatures) are evaluated. It is found that the building considered in this study can save up to 41.87% energy without compromising occupancies thermal comfort by implementing the above mentioned ECMs into the existing system.

A Qualitative Analysis of the Use of Financial Services and Saving Behavior Among Older African Americans and Latinos in the Los Angeles Area

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Luisa R. Blanco

2015-01-01

Full Text Available For this study, we conducted seven focus groups in the Los Angeles area with a total of 70 participants (42 Latinos and 28 African Americans recruited from three senior centers and a church. There was a wide variety of responses in relation to the usage of financial services among participants. We found that although some participants seem to participate more in the formal financial sector and show a higher level of sophistication when managing their finances, other participants’ use of formal financial institutions is minimal. Among African American participants, we found several instances in which individuals feel very comfortable using banks. Lower levels of participation in the formal financial sector were found among the lower income Latino participants. In relation to barriers to participate in the financial sector, supply was not an issue, but demand and behavioral factors seem more important. Overall, no participants saved very much on a regular basis. We also find that participants in general do not want to ask their children for money, and also do not want to save and accumulate wealth to leave to their children.

Influence of organic phosphorus on reproductive performance and metabolic profiles of anoestrous Farafra ewes in subtropics at the end of breeding season.

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Senosy, W; Kassab, A Y; Hamdon, H A; Mohammed, A A

2018-05-07

The effect of organic phosphorus on metabolic, haematological and hormonal status, restoration of ovarian functions and conception rate in anoestrous Farafra ewes in subtropics were evaluated. Anoestrous Farafra ewes (n = 24; 34.72 ± 0.52 kg body weight) were allocated into two equal groups: control and phosphorus groups. The ewes of phosphorus group were treated with sodium 4-dimethylamino-2-methyl-phenyl-phosphonate as an organic bound phosphorous twice a week for successive 3 weeks. Ovarian follicle development and corpora lutea were checked three times a week till occurrence of oestrus using ultrasonography while pregnancy was confirmed at 30 days post-service. Plasma metabolites, reproductive hormones, thyroid hormones and minerals were detected at weeks -2, -1, 0 (mating day) and + 4 weeks post-oestrus. Phosphorus group had significantly (p ewes (2.1 ± 0.8 weeks vs. 4.6 ± 1.1 weeks). In addition, phosphorous supplementation significantly (p ewes (10.8 ± 0.44; p ewes in subtropics could improve reproductive performance and restore ovarian activity at the end of spring and early summer. © 2018 Blackwell Verlag GmbH.

Fauna of phlebotomine sand flies (Diptera, Psychodidae in areas with endemic American cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil

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Paulo Silva de Almeida

2013-03-01

Full Text Available Fauna of phlebotomine sand flies (Diptera, Psychodidae in areas with endemic American cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil. The aim of this study was to investigate the ecological aspects of the main vectors of American cutaneous leishmaniasis (ACL in four monitoring stations situated in the municipalities of Naviraí, Nova Andradina, Novo Horizonte do Sul and Rio Verde de Mato Grosso. For each monitoring station, the captures of sand flies were undertaken each month from July 2008 to June 2010 using CDC and Shannon traps. The CDC traps were installed simultaneously for three consecutive nights in three collection sites: intradomicile, peridomicile and edge of the forest. A Shannon trap was installed from dusk to 10 pm, inside the forest, one night per month. A total of 7,651 sand flies belonging to nine genera and twenty-nine species were captured. Nyssomyia neivai (52.95%, Psathyromyia hermanlenti (10.91%, Psathyromyia runoides (9.16%, Nyssomyia whitmani (7.95%, Psathyromyia aragaoi (4. 89%, Nyssomyia antunesi (3.14% and Evandromyia bourrouli (2.20% were the most frequent species. Approximately 65% of the sand flies were collected in the forest environment. The municipalities presented significantly different indexes of species diversity. Naviraí presented the lowest species diversity index, however, it showed the highest abundance. Novo Horizonte do Sul had the highest species diversity index, but the lowest abundance (< 5%. It is noteworthy the occurrence of vector species of Leishmania in the areas studied, especially in Naviraí, where Ny. neivai presented high frequencies which may explain the increased number of ACL cases in this municipality.

Ethnic differences in inter- and intra-situational blood pressure variation: Comparisons among African-American, Hispanic-American, Asian-American, and European-American women.

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James, Gary D; Bovbjerg, Dana H; Hill, Leah A

2016-11-01

The purpose of this study was to compare the daily inter- and intra-situational ambulatory blood pressure (BP) variation by ethnicity in women. The African-American (N = 82; Age = 39.7 + 8.9), Hispanic-American (N = 25; age = 37.5 + 9.4), Asian-American (N = 22; Age = 35.2 + 8.6), and European-American (N = 122; Age = 37.2+ 9.4) women in this study all worked in similar positions at two major medical centers in NYC. Each wore an ambulatory monitor during the course of one mid-week workday. Proportional BP changes from work or home to sleep, intra-situational BP variation (standard deviation [SD]) and mean situational BP levels were compared among the groups using ANOVA models. African-American and Asian-American women had significantly smaller proportional work-sleep systolic changes than either European- (P women, but the Asian-American women's changes tended to be smallest. The variability (SD) of diastolic BP at work was significantly greater among African- and Hispanic-American women compared to Asian- and European-American women (all P women had greater sleep variability than European-American women (P Asian-American women had the highest level of sleep diastolic pressure (all comparisons P Asian-American women have an attenuated proportional BP decline from waking environments to sleep compared to European-American and Hispanic-American women. Asian-American nocturnal BP may be elevated relative to all other groups. Am. J. Hum. Biol. 28:932-935, 2016. © 2016Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

American Nuclear Society 1994 student conference eastern region

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

This report contains abstracts from the 1994 American Nuclear Society Student Conference. The areas covered by these abstracts are: fusion and plasma physics; nuclear chemistry; radiation detection; reactor physics; thermal hydraulics; and corrosion science and waste issues.

American Nuclear Society 1994 student conference eastern region

International Nuclear Information System (INIS)

1994-01-01

This report contains abstracts from the 1994 American Nuclear Society Student Conference. The areas covered by these abstracts are: fusion and plasma physics; nuclear chemistry; radiation detection; reactor physics; thermal hydraulics; and corrosion science and waste issues

Communication, coping, and quality of life of breast cancer survivors and family/friend dyads: a pilot study of Chinese-Americans and Korean-Americans.

Science.gov (United States)

Lim, Jung-Won

2014-11-01

This study aimed to understand the dyadic relationships between family communication and quality of life (QOL) and between coping and QOL in Chinese-American and Korean-American breast cancer survivor (BCS)-family member dyads. A cross-sectional survey design was used. A total of 32 Chinese-American and Korean-American BCS-family member dyads were recruited from the California Cancer Surveillance Program and area hospitals in Los Angeles County, California, USA. The dyadic data were analyzed using a pooled regression actor-partner interdependence model. The study findings demonstrated that the survivors' general communication and use of reframing coping positively predicted their own QOL. The survivors' and family members' general communication was also a strong predictor of the family members' physical-related QOL score specifically. Meanwhile, each person's use of mobilizing coping negatively predicted his or her partner's QOL. The study findings add important information to the scarce literature on the QOL of Asian-American survivors of breast cancer. The findings suggest that Chinese-American and Korean-American BCS and their family members may benefit from interventions that enhance communication and coping within the family unit. Copyright © 2014 John Wiley & Sons, Ltd.

Close relationships between Asian American and European American college students.

Science.gov (United States)

Chen, C; Edwards, K; Young, B; Greenberger, E

2001-02-01

The authors examined attitudes and behaviors regarding close relationships between European and Asian Americans, with a particular emphasis on 5 major subgroups of Asian Americans (Chinese, Japanese, Korean, Vietnamese, and Filipino Americans). Participants were 218 Asian American college students and 171 European American college students attending a culturally diverse university. The European Americans did not differentiate among the various subgroups of Asian Americans. Their attitudes regarding close relationships were less positive toward Asian Americans than toward Mexican and African Americans, a finding contrary to the prediction of social exchange theory (H. Tajfel, 1975). In contrast to the European Americans' view of homogeneity among Asian Americans, the 5 major subgroups of Asian Americans expressed a distinctive hierarchy of social preference among themselves. Results are discussed in terms of their implications for future research on interethnic relations involving Asian Americans.

Religious values and healthcare accommodations: voices from the American Muslim community.

Science.gov (United States)

Padela, Aasim I; Gunter, Katie; Killawi, Amal; Heisler, Michele

2012-06-01

Minority populations receive a lower quality healthcare in part due to the inadequate assessment of, and cultural adaptations to meet, their culturally informed healthcare needs. The seven million American Muslims, while ethnically and racially diverse, share religiously informed healthcare values that influence their expectations of healthcare. There is limited empirical research on this community's preferences for cultural modifications in healthcare delivery. Identify healthcare accommodations requested by American Muslims. Using community-based participatory research (CBPR) methods, we partnered with four community organizations in the Greater Detroit area to design and conduct thirteen focus groups at area mosques serving African American, Arab American, and South Asian American Muslims. Qualitative content analysis utilized a framework team-based approach. Participants reported stigmatization within the healthcare system and voiced the need for culturally competent healthcare providers. In addition, they identified three key healthcare accommodations to address Muslim sensitivities: the provision of (1) gender-concordant care, (2) halal food and (3) a neutral prayer space. Gender concordance was requested based on Islamic conceptions of modesty and privacy. Halal food was deemed to be health-promoting and therefore integral to the healing process. Lastly, a neutral prayer space was requested to ensure security and privacy during worship. This study informs efforts to deliver high-quality healthcare to American Muslims in several ways. We note three specific healthcare accommodations requested by this community and the religious values underlying these requests. Healthcare systems can further cultural sensitivity, engender trust, and improve the healthcare experiences of American Muslims by understanding and then attempting to accommodate these values as much as possible.