Sample records for amazon river prawn

  1. Toxicity of rotenone to giant river freshwater prawn Macrobrachium rosenbergii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquaculturists have often suffered predation losses in the production of freshwater giant river prawn Macrobrachium rosenbergii due to the presence of wild fish species in culture ponds. The piscicide rotenone is widely used to remove undesirable fish species from ponds. Although evidence in the t...

  2. The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system

    E-print Network

    Bermingham, Eldredge

    The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system Keywords: Amazon basin Amazon River Late Miocene Paleogeography Paleoecology fossil vertebrates palinology

  3. cDNA Cloning and Expression Analysis of Gustavus Gene in the Oriental River Prawn Macrobrachium nipponense

    PubMed Central

    Zhang, Fengying; Chen, Liqiao; Qin, Jianguang; Zhao, Weihong; Wu, Ping; Yu, Na; Ma, Lingbo

    2011-01-01

    The gustavus gene is required for localizing pole plasm and specifying germ cells. Research on gustavus gene expression will advance our understanding of the biological function of gustavus in animals. A cDNA encoding gustavus protein was identified and termed MnGus in the oriental river prawn Macrobrachium nipponense. Bioinformatic analyses showed that this gene encoded a protein of 262 amino acids and the protein belongs to the Spsb1 family. Real-time quantitative PCR analyses revealed that the expression level of MnGus in prawn embryos was slightly higher at the cleavage stage than at the blastula stage, and reached the maximum level during the zoea stage of embryos. The minimum level of MnGus expression occurred during the perinucleolus stage in the ovary, while the maximum was at the oil globule stage, and then the level of MnGus expression gradually decreased with the advancement of ovarian development. The expression level of MnGus in muscle was much higher than that in other tissues in mature prawn. The gustavus cDNA sequence was firstly cloned from the oriental river prawn and the pattern of gene expression was described during oocyte maturation, embryonic development, and in other tissues. The differential expression patterns of MnGus in the embryo, ovary and other somatic tissues suggest that the gustavus gene performs multiple physiological functions in the oriental river prawn. PMID:21359189

  4. Effects of Host Phylogeny and Habitats on Gut Microbiomes of Oriental River Prawn (Macrobrachium nipponense)

    PubMed Central

    Chen, Po-Cheng; Weng, Francis Cheng-Hsuan; Jean, Wen Dar; Wang, Daryi

    2015-01-01

    The gut microbial community is one of the richest and most complex ecosystems on earth, and the intestinal microbes play an important role in host development and health. Next generation sequencing approaches, which rapidly produce millions of short reads that enable the investigation on a culture independent basis, are now popular for exploring microbial community. Currently, the gut microbiome in fresh water shrimp is unexplored. To explore gut microbiomes of the oriental river prawn (Macrobrachium nipponense) and investigate the effects of host genetics and habitats on the microbial composition, 454 pyrosequencing based on the 16S rRNA gene were performed. We collected six groups of samples, including M. nipponense shrimp from two populations, rivers and lakes, and one sister species (M. asperulum) as an out group. We found that Proteobacteria is the major phylum in oriental river prawn, followed by Firmicutes and Actinobacteria. Compositional analysis showed microbial divergence between the two shrimp species is higher than that between the two populations of one shrimp species collected from river and lake. Hierarchical clustering also showed that host genetics had a greater impact on the divergence of gut microbiome than host habitats. This finding was also congruent with the functional prediction from the metagenomic data implying that the two shrimp species still shared the same type of biological functions, reflecting a similar metabolic profile in their gut environments. In conclusion, this study provides the first investigation of the gut microbiome of fresh water shrimp, and supports the hypothesis of host species-specific signatures of bacterial community composition. PMID:26168244

  5. Mouths of the Amazon River, Brazil, South America

    NASA Technical Reports Server (NTRS)

    1992-01-01

    In this view of the Amazon River Mouth (0.0, 51.0W), a large sediment plume can be seen expanding outward into the Atlantic Ocean. The sediment plume can be seen hugging the coast north of the delta as a result of the northwest flowing coastal Guyana Current. In recent years, the flow of the Amazon has become heavily laden with sediment as soil runoff from the denuded landscape of the interior enters the Amazon River (and other rivers) drainage system.

  6. River dynamics and the diversity of Amazon lowland forest

    Microsoft Academic Search

    Jukka Salo; Risto Kalliola; Ilmari Häkkinen; Yrjö Mäkinen; Pekka Niemelä; Maarit Puhakka; Phyllis D. Coley

    1986-01-01

    We suggest here that large-scale natural forest disturbance and primary succession in the lowland rainforests of the Peruvian Amazon is caused by lateral erosion and channel changes of meandering rivers. Our results indicate that in the upper Amazon region, primary succession on newly deposited riverine soils is a major mode of forest regeneration. Landsat imagery analyses show that 26.6% of

  7. Screening of parasitic and IHHNV infections in wild giant freshwater prawn Macrobrachium rosenbergii from Rejang River at Kuching, Sarawak.

    PubMed

    Kua, Beng Chu; Choong, F C; Hazreen Nita, M K; Muhd Faizul H, A H; Bhassu, S; Imelda, R R; Mohammed, M

    2011-04-01

    A preliminary survey of parasitic and infectious hypodermal and haematopoietic necrosis virus (IHHNV) infections in giant freshwater prawn from the Damak Sea of Rejang River, Kuching, Sarawak was conducted. Symptoms of black spots/patches on the rostrum, carapace, pleopods or telson were observed in most of the 107 samples collected. Parasitic examination revealed sessiline peritrichs such as (Zoothamnium sp.), nematode larvae, gregarine stage and cocoon of leech with prevalences of 1.2%, 1.2%, 5% and 17% respectively. Under histopathological examination, changes like accumulation of hemocytes around hepatopancreatic tubules due to vibriosis, basophilic intranuclear inclusions in the epithelium and E-cell of hepatopancreatic tubules as a result of HPV were seen through the section. No positive infection of IHHNV was detected in 78 samples. As such, the wild giant freshwater prawns in Damak Sea of Rejang River in Kuching are IHHNV-free though infections of parvo-like virus and bacteria were seen in histopathology. PMID:21602773

  8. Sediment budget of the Napo River, Amazon basin, Ecuador and Peru A., Laraque1

    E-print Network

    Paris-Sud XI, Université de

    transfer and geodynamic processes at the Andean Piedmont. Key Words : Amazon River basin, Sediment yield and Meade, 1983). Most of the sediment discharged (95%) to the Atlantic Ocean by the Amazon River comes from

  9. Complete larval development of the Monkey River Prawn Macrobrachium lar (Palaemonidae) using a novel greenwater technique.

    PubMed

    Lal, Monal M; Seeto, Johnson; Pickering, Timothy D

    2014-01-01

    This study documents the complete larval development of the Monkey River Prawn Macrobrachium lar using a new greenwater rearing technique. Approximately 6,000 larvae were reared for 110 days at an initial stocking density of 1 ind./6 L. Salinity at hatch was 10?±?2 ppt and progressively increased to 30?±?2 ppt until decapodids had metamorphosed. Temperature was maintained at 28?±?0.5°C, pH at 7.8?±?0.2, DO2?>?6.5 mg/L and NH(4+) and NH3???1.5 and ?0.1 ppm respectively throughout the culture period. Larval development was extended and occurred through 13 zoeal stages, with the first decapodid measuring 6.2?±?0.63 mm in total length observed after 77 days. 5 decapodids in total were produced, and overall survival to this stage was 0.08%. Overall, the pattern of larval growth shares similarities with those of other Macrobrachium spp. that have a prolonged/normal type of development, and it is likely that larvae underwent mark time moulting which contributed to the lengthened development duration. While this study represents a significant breakthrough in efforts to domesticate M. lar, improvement of larval survival rates and decreased time till metamorphosis are required before it can become fully viable for commercial scale aquaculture. PMID:25332868

  10. Seasonality of Reproduction in Amazon River Dolphins (Inia geoffrensis) in Three Major River Basins of South America

    Microsoft Academic Search

    Tamara L. McGuire; Enzo R. Aliaga-Rossel

    2007-01-01

    Reproduction of Amazon River Dolphins, Inia geoffrensis, is generally reported to be highly seasonal; however, this conclusion is based on studies from only one area of Inia distribution from throughout the Amazon and Orinoco river basins. Our observations of live dolphins from the Orinoco, Amazon, and Mamore river basins (in Venezuela, Peru and Bolivia, respectively) indicate that reproduction in Inia

  11. Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean

    E-print Network

    Subramaniam, Ajit

    #12;Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean in carbon sequestration. Here, we report that the Amazon River plume supports N2 fixation far from the mouth of atmospheric carbon to the deep ocean (3), or ``carbon sequestration'' (4). The Amazon River has the largest

  12. Factors driving the biogeochemical budget of the Amazon River and its statistical modelling

    E-print Network

    Paris-Sud XI, Université de

    Factors driving the biogeochemical budget of the Amazon River and its statistical modelling the period 1982­1984 during the Carbon in the AMazon River Experiment (CAMREX) project. The relevant factors-regressive model coupled to variance analysis. Basically, the compositional fluctuations in the Amazon River

  13. The Prawn Macrobrachium vollenhovenii in the Senegal River Basin: Towards Sustainable Restocking of All-Male Populations for Biological Control of Schistosomiasis

    PubMed Central

    Savaya Alkalay, Amit; Rosen, Ohad; Sokolow, Susanne H.; Faye, Yacinthe P. W.; Faye, Djibril S.; Aflalo, Eliahu D.; Jouanard, Nicolas; Zilberg, Dina; Huttinger, Elizabeth; Sagi, Amir

    2014-01-01

    Early malacological literature suggests that the outbreak of schistosomiasis, a parasitic disease transmitted by aquatic snails, in the Senegal River basin occurred due to ecological changes resulting from the construction of the Diama dam. The common treatment, the drug praziquantel, does not protect from the high risk of re-infection due to human contact with infested water on a daily basis. The construction of the dam interfered with the life cycle of the prawn Macrobrachium vollenhovenii by blocking its access to breeding grounds in the estuary. These prawns were demonstrated to be potential biological control agents, being effective predators of Schistosoma-susceptible snails. Here, we propose a responsible restocking strategy using all-male prawn populations which could provide sustainable disease control. Male prawns reach a larger size and have a lower tendency to migrate than females. We, therefore, expect that periodic restocking of all-male juveniles will decrease the prevalence of schistosomiasis and increase villagers' welfare. In this interdisciplinary study, we examined current prawn abundance along the river basin, complemented with a retrospective questionnaire completed by local fishermen. We revealed the current absence of prawns upriver and thus demonstrated the need for restocking. Since male prawns are suggested to be preferable for bio-control, we laid the molecular foundation for production of all-male M. vollenhovenii through a complete sequencing of the insulin-like androgenic gland-encoding gene (IAG), which is responsible for sexual differentiation in crustaceans. We also conducted bioinformatics and immunohistochemistry analyses to demonstrate the similarity of this sequence to the IAG of another Macrobrachium species in which neo-females are produced and their progeny are 100% males. At least 100 million people at risk of schistosomiasis are residents of areas that experienced water management manipulations. Our suggested non-breeding sustainable model of control—if proven successful—could prevent re-infections and thus prove useful throughout the world. PMID:25166746

  14. Holocene coastal vegetation changes at the mouth of the Amazon River

    Microsoft Academic Search

    Clarisse Beltrão Smith; Marcelo Cancela Lisboa Cohen; Luiz Carlos Ruiz Pessenda; Marlon Carlos França; José Tasso Felix Guimarães; Dilce de Fátima Rossetti; Rubén José Lara

    2011-01-01

    Wetland dynamics in the eastern Amazon region during the past 7000years were studied using pollen, textural and structural analyses of sediment cores, as well as AMS radiocarbon dating. Four sediment cores were sampled from Marajó Island, which is located at the mouth of the Amazon River. Marajó Island is covered mainly by Amazon coastal forest, as well as herbaceous and

  15. The history of the introduction of the giant river prawn, Macrobrachium cf. rosenbergii (Decapoda, Palaemonidae), in Brazil: New insights from molecular data

    PubMed Central

    Iketani, Gabriel; Pimentel, Luciana; Silva-Oliveira, Glaúcia; Maciel, Cristiana; Valenti, Wagner; Schneider, Horacio; Sampaio, Iracilda

    2011-01-01

    The giant river prawn, Macrobrachium cf. rosenbergii, is one of the most cultivated freshwater prawns in the world and has been introduced into more than 40 countries. In some countries, this prawn is considered an invasive species that requires close monitoring. Recent changes in the taxonomy of this species (separation of M. rosenbergii and M. dacqueti) require a re-evaluation of introduced taxa. In this work, molecular analyses were used to determine which of these two species was introduced into Brazil and to establish the geographic origin of the introduced populations that have invaded Amazonian coastal waters. The species introduced into Brazil was M. dacqueti through two introduction events involving prawns originating from Vietnam and either Bangladesh or Thailand. These origins differ from historical reports of the introductions and underline the need to confirm the origin of other exotic populations around the world. The invading populations in Amazonia require monitoring not only because the biodiversity of this region may be affected by the introduction, but also because admixture of different native haplotypes can increase the genetic variability and the likelihood of persistence of the invading species in new habitats. PMID:21637558

  16. Effect of thermal acclimation on organ mass, tissue respiration, and allometry in Leichhardtian river prawns Macrobrachium tolmerum (Riek, 1951).

    PubMed

    Crispin, Taryn S; White, Craig R

    2013-01-01

    Changes to an animal's abiotic environment-and consequent changes in the allometry of metabolic rate in the whole animal and its constituent parts-has considerable potential to reveal important patterns in both intraspecific and interindividual variation of metabolic rates. This study demonstrates that, after 6 wk of thermal acclimation at replicate treatments of 16°, 21°, and 25°C, standard metabolic rate (SMR) scales allometrically in Leichhardtian river prawns Macrobrachium tolmerum ([Formula: see text]) and that the scaling exponent and normalization constant of the relationship between SMR and body mass is not significantly different among acclimation treatments when measured at 21°C. There is, however, significant variation among individuals in whole-animal metabolic rate. We hypothesized that these observations may arise because of changes in the metabolic rate and allometry of metabolic rate or mass of organ tissues within the animal. To investigate this hypothesis, rates of oxygen consumption in a range of tissues (gills, gonads, hepatopancreas, chelae muscle, tail muscle) were measured at 21°C and related to the body mass (M) and whole-animal SMR of individual prawns. We demonstrate that thermal acclimation had no effect on organ and tissue mass, that most organ and tissue (gills, gonads, hepatopancreas) respiration rates do not change with acclimation temperature, and that residual variation in the allometry of M. tolmerum SMR is not explained by differences in organ and tissue mass and respiration rates. These results suggest that body size and ambient temperature may independently affect metabolic rate in this species. Both chelae and tail muscle, however, exhibited a reduction in respiration rate in animals acclimated to 25° relative to those acclimated to 16° and 21°C. This reduction in respiration rates of muscle at higher temperatures is evidence of a tissue-specific acclimation response that was not detectable at the whole-animal level. PMID:23799841

  17. The Amazon River exits the Andes mountains more than 4000 kilometers (km) from its estuary,but along its

    E-print Network

    McClain, Michael

    Articles The Amazon River exits the Andes mountains more than 4000 kilometers (km) from its estuary of the environment and distinct aquatic eco- systems of the lowland Amazon River (summarized in Sioli [1984], Junk source of sediments and solutes to the lower reaches of the Amazon River.The most visible characteristics

  18. PUBLISHED ONLINE: 21 NOVEMBER 2010 | DOI: 10.1038/NGEO1017 Miocene drainage reversal of the Amazon River

    E-print Network

    Liu, Lijun

    of the Amazon River driven by plate­mantle interaction G. E. Shephard1 *, R. D. Müller1 , L. Liu2 and M. Gurnis2 by the formation of the eastward-draining Amazon River, which has been attributed to Andean uplift1­5 . However the establishment of the Amazon River, suggesting that mantle convection can profoundly affect the evolution

  19. 2005 drought event in the Amazon River basin as measured by GRACE and estimated by climate models

    E-print Network

    Yang, Zong-Liang

    2005 drought event in the Amazon River basin as measured by GRACE and estimated by climate models J extreme drought event in the Amazon river basin, regarded as the worst in over a century. GRACE measures. Yang, and G. Y. Niu (2009), 2005 drought event in the Amazon River basin as measured by GRACE

  20. Amazon River water in the northeastern Caribbean Sea and its effect on larval reef fish assemblages during April 2009

    E-print Network

    Amazon River water in the northeastern Caribbean Sea and its effect on larval reef fish assemblages.S.A. ABSTRACT During April to June 2009, a large bolus of Amazon River water impacted the northeastern Caribbean words: Amazon River plume, Caribbean Sea, chlorophyll-a, hydrography, larval fish assemblages, North

  1. Amazon River carbon dioxide outgassing fuelled by wetlands.

    PubMed

    Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C; Savoye, Nicolas; Deborde, Jonathan; Souza, Edivaldo Lima; Albéric, Patrick; Landim de Souza, Marcelo F; Roland, Fabio

    2014-01-16

    River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters. PMID:24336199

  2. Molecular cloning and expression analysis of female sterile homeotic gene (fsh) in the oriental river prawn Macrobrachium nipponense.

    PubMed

    Zhang, W Y; Jiang, S F; Xiong, Y W; Fu, H T; Qiao, H; Sun, S M; Gong, Y S; Jin, S B

    2015-01-01

    The gene female sterile homeotic (fsh) plays crucial roles in molecular function, including protein kinase activity and DNA binding, which are involved in biological processes such as terminal region determination and negative regulation of DNA-dependent transcription. Although fsh has been found in Drosophila melanogaster, little is known regarding its expression in crustaceans. In this study, a fsh gene homologue, designated as Mnfsh, was cloned and characterized from the testis of the oriental river prawn, Macrobrachium nipponense, by using EST analysis and the RACE approach for the first time. The full-length cDNA of Mnfsh was 2029 bp, consisting of a 5' UTR of 361 bp, a 3' UTR of 216 bp, and an ORF of 1452 bp encoding 484 amino acids. qRT-PCR analysis showed that the Mnfsh gene was expressed in the testis, ovary, muscle, heart, eyestalk, and abdominal ganglion, with the highest level of expression in the ovary and the lowest in the heart. qRT-PCR analyses showed that the expression levels of Mnfsh mRNA both significantly increased in the zoea stage, the VII larvae, and 1st day post-larvae after metamorphosis. In conclusion, the results of the present study indicate that Mnfsh is an arthropod fsh homologue and probably also plays important roles in embryogenesis, organogenesis, and morphological differentiation of M. nipponense. PMID:25966204

  3. Lithium isotopes fractionation in Amazon river-borne material

    NASA Astrophysics Data System (ADS)

    Dellinger, M.; Gaillardet, J.; Louvat, P.; Bouchez, J.; France-Lanord, C.

    2012-12-01

    Silicate weathering is a key geological process controlling the long-term climatic cycle through the consumption of atmospheric CO2. The determination of paleo-weathering conditions is therefore critical to understand past climatic variations. For this purpose, there is evidence from numerous recent studies that Li isotopes in river-dissolved load could be a potentially good silicate weathering proxy because (i) Li is derived predominately from silicates rocks (ii) Li is mobile during chemical weathering and (iii) the water/rocks interactions induce the fractionation of Li isotopes with the preferential enrichment of 7Li in the dissolved phase. However, the respective influence of factors and weathering regime on the Li isotopes fractionation during chemical weathering is still poorly understood. In this study we investigate the Li isotopic fractionation in river-borne material of the largest river system on Earth, the Amazon River. This river system offers the possibility to study Li isotopes fractionation by chemical weathering at a continental scale, in a relatively unpolluted area with equatorial conditions and, to compare weathering and transport limited regimes of erosion. First results show that about 5 to 15% of the total lithium is transported in the dissolved phase. The dissolved Li isotopes composition (?7Li) ranges from +6.4‰ to +30.8‰ and is much heavier than corresponding sand and suspended sediments samples (-3.6‰ to +4‰). Rio Negro have the lowest ?7Li values (+6.4‰) while Mamore River in the Madeira basin have the heaviest ?7Li composition (+30.8‰). Mass budget calculation between dissolved and particulate phases provides insights about the respective influence of parameters controlling the extent of Li isotopes fractionation during chemical weathering.

  4. Sediment supply as a driver of river evolution in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Ahmed, Joshua; Constantine, José Antonio; Dunne, Thomas; Legleiter, Carl; Lazarus, Eli D.

    2015-04-01

    The Amazon represents the only large river basin in the world where there is a sufficient range of sediment supplies and a lack of engineering controls to assess how sediment supply drives the evolution of meandering rivers. Despite recent analytical advances (Asahi et al., 2013; Pittaluga and Seminara, 2011), modern theory does not yet identify or explain the effects of externally imposed sediment supplies, a fundamental river characteristic, on meandering river evolution. These sediment supplies would be radically reduced by the construction of large dams proposed for the Amazon Basin (Finer and Jenkins, 2012). Here, we demonstrate that the sediment loads imposed by their respective drainage basins determine planform changes in lowland rivers across the Amazon. Our analysis, based on Landsat image sequences, indicates that rivers with high sediment loads draining the Andes and associated foreland basin experience annual migration rates that are on average four times faster than rivers with lower sediment loads draining the Central Amazon Trough and shields. Incidents of meander cutoff also occur more frequently along the rivers of the Andes and foreland basin, where the number of oxbows in the floodplains is more than twice that observed in the floodplains of the Central Amazon Trough and shields. Our results, which cannot be explained by differences in channel slope or hydrology, highlight the importance of sediment supply in modulating the ability of meandering alluvial rivers to reshape the floodplain environment through river migration. Asahi, K., Shimizu, Y., Nelson, J., Parker, G., 2013. Numerical simulation of river meandering with self-evolving banks. Journal of Geophysical Research: Earth Surface, 118(4), 2013JF002752. Finer, M., Jenkins, C.N., 2012. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity. PLOS One, 7(4), e35126. Pittaluga, M.B., Seminara, G., 2011. Nonlinearity and unsteadiness in river meandering: a review of progress in theory and modelling. Earth Surface Processes and Landforms, 36(1), 20-38.

  5. The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system

    NASA Astrophysics Data System (ADS)

    Latrubesse, Edgardo M.; Cozzuol, Mario; da Silva-Caminha, Silane A. F.; Rigsby, Catherine A.; Absy, Maria Lucia; Jaramillo, Carlos

    2010-05-01

    On the basis of paleontological content (vertebrates and palynology) and facies analysis from river banks, road cuts, and three wells, we have assigned the uppermost levels of the Solimões Formation in western Amazonia, Brazil, to the Late Miocene. The vertebrate fossil record from outcropping sediments is assigned to the Huayquerian-Mesopotamian mammalian biozones, spanning 9-6.5 Ma. Additionally, we present results that demonstrate that deposits in Peruvian Amazonia attributed to Miocene tidal environments are actually fluvial sediments that have been misinterpreted (both environmentally and chronologically) by several authors. The entire Late Miocene sequence was deposited in a continental environment within a subsiding basin. The facies analysis, fossil fauna content, and palynological record indicate that the environment of deposition was dominated by avulsive rivers associated with megafan systems, and avulsive rivers in flood basins (swamps, lakes, internal deltas, and splays). Soils developed on the flatter, drier areas, which were dominated by grasslands and gallery forest in a tropical to subtropical climate. These Late Miocene sediments were deposited from westward of the Purus arch up to the border of Brazil with Peru (Divisor Ranges) and Bolivia (Pando block). Eastward of the Iquitos structural high, however, more detailed studies, including vertebrate paleontology, need to be performed to calibrate with more precision the ages of the uppermost levels of the Solimões Formation. The evolution of the basin during the late Miocene is mainly related to the tectonic behavior of the Central Andes (˜ 3°-15°S). At approximately 5 Ma, a segment of low angle of subduction was well developed in the Nazca Plate, and the deformation in the Subandean foreland produced the inland reactivation of the Divisor/Contamana Ranges and tectonic arrangements in the Eastern Andes. During the Pliocene southwestern Brazilian Amazonia ceased to be an effective sedimentary basin, and became instead an erosional area that contributed sediments to the Amazon fluvial system. At that time, the lowland fluvial systems of southwestern Amazonia (the Purus, Jurua and Javarí basins) become isolated from the Andes by the newly formed north-flowing Ucayali system and south-east flowing Madre de Dios System. It was during the early Pliocene that the Amazon fluvial system integrated regionally and acquired its present appearance, and also when it started to drain water and sediments on a large scale to the Atlantic Ocean.

  6. Molecular cloning, characterization, and expression analysis of two different types of lectins from the oriental river prawn, Macrobrachium nipponense.

    PubMed

    Xiu, Yunji; Wang, Yinghui; Jing, Yunting; Qi, Yakun; Ding, Zhengfeng; Meng, Qingguo; Wang, Wen

    2015-08-01

    Lectins, which are widely expressed in invertebrates, play important roles in many biological processes, including protein trafficking, cell signaling, pathogen recognition, as effector molecules, and so on (Wang and Wang, 2013). This study identified one novel M-type lectin and one L-Type lectin, designated as MnMTL1 and MnLTL1, from the oriental river prawn Macrobrachium nipponense. The full-length cDNA of MnMTL1 was 2064 bp with a 1761 bp ORF encoding a putative protein of 586 deduced amino acids. The full-length cDNA of MnLTL1 was 1744 bp with a 972 bp ORF encoding a 323-amino acid peptide. The deduced MnMTL1 protein contained a putative type II transmembrane region and a 440-aa Glycoside hydrolase family 47 (GH47) domain. One luminal carbohydrate recognition domain and a 23-aa type I transmembrane region were identified from the MnLTL1. MnMTL1 shared 78% identity with Marsupenaeus japonicus M-type lectin and MnLTL1 shared 83% similarity with M. japonicus L-type lectin. RT-PCR analysis showed that MnMTL1 and MnLTL1 were expressed in all tested tissues. Quantitative real-time PCR analysis revealed that MnMTL1 and MnLTL1 are substantially fluctuant during Aeromonas hydrophila and Aeromonas veronii infections. Based on immune responses and previous literature, we assumed that MnMTL1 and MnLTL1 might be functioned as pattern recognition receptors and play important roles in the immune response of M. nipponense. PMID:25929240

  7. PUBLISHED ONLINE: XX MONTH XXXX | DOI: 10.1038/NGEO1017 Miocene drainage reversal of the Amazon River

    E-print Network

    Müller, Dietmar

    of the Amazon River driven by plate­mantle interaction G. E. Shephard1 *, R. D. Müller1 , L. Liu2 and M. Gurnis2 by the formation of the4 eastward-draining Amazon River, which has been attributed5 to Andean uplift1­5 . However towards26 the Atlantic. This shift, initiating the fluviolacustrine system that27 is now the Amazon River

  8. Interannual variability in water storage over 2003-2007 in the Amazon Basin2 from GRACE space gravimetry, in situ river level3

    E-print Network

    Boyer, Edmond

    2003-2007 of different hydrological parameters in28 the Amazon river basin: vertically-integrated water storage from the GRACE space gravimetry29 mission, surface water level over the Amazon River and its storage from GRACE and31 in situ river level along the Amazon River and its main tributaries. We also

  9. Modern Environmental Changes on Amapa Coastal Plain under Amazon River Influence

    Microsoft Academic Search

    V. F. Santos; A. G. Figueiredo; O. M. Silveira; L. Polidori

    2007-01-01

    The Amazonian coastal environment is very dynamic compared to other coasts. It is situated at the edge of the Earth's largest forest, and is segmented by fluvial systems, with the biggest being the Amazon River. The rivers are particularly influenced by the Intertropical Convergence Zone (ITCZ), which controls the water and particle discharge, and the flooding regime. Moderate and strong

  10. Freshwater fishes of the Amazon River basin: their biodiversity, fisheries, and habitats

    Microsoft Academic Search

    Wolfgang J. Junk; Maria Gercilia Mota Soares; Peter B. Bayley

    2007-01-01

    Stretching more than seven million square kilometers, the Amazon River basin is the largest river basin in the world and discharges about one-sixth of all freshwater from the continents to the oceans of the world. The age of this ecosystem, its position near the equator and the enormous diversity of its aquatic habitats, have produced the most diverse fish fauna

  11. Water resources, salinity and salt yields of the rivers of the Bolivian Amazon

    NASA Astrophysics Data System (ADS)

    Roche, Michel-Alain; Jauregui, Carlos Fernandez

    1988-06-01

    This is the first time that the water resources, the salinity and the yields of the upper basins of the Madera River have been reported. Formed by the confluence of the Beni and Mamore, the Madera is one of the world's largest rivers: 17,000 m 3s -1, approximately half the discharge of the Congo River. It has a dissolved discharge close to that of the Congo River: 1 ts -1 of ions. Likewise, the Beni and the Mamore Rivers, are also classified as large rivers, greater than the Volga River, the largest in Europe, and the Niger River, the second largest in Africa. The amounts of water involved are considerable. The average dissolved content of these rivers, 57-61 mg l -1 respectively, is relatively low to medium. Many types of water, classified according to their ionic compositions, have been characterized in the Andes, the Amazon Plain, and in the main drainage axis. The slightly mineralized black water of the plain seems the most unique type. Recycling of water vapor in the Amazon Basin is confirmed by the low chloride and sodium contents of the water in the plain. Thus the importance of this phenomenon in the genesis of rainfall throughout the basin is emphasized. The contribution of the Upper Madera River to the Amazon River is 9.7% of the water and 10.9% of ionic load.

  12. Large-scale hydrologic and hydrodynamic modelling of the Amazon River basin2 Rodrigo Cauduro Dias de Paiva1,2

    E-print Network

    Paris-Sud XI, Université de

    1 Large-scale hydrologic and hydrodynamic modelling of the Amazon River basin2 3 4 Rodrigo Cauduro/hydrodynamic modelling of the Amazon River basin24 is presented using the MGB-IPH model with a validation using remotely vulnerability to natural hazards, particularly in55 the Amazon River basin, where extreme hydrological events

  13. Mid and late-Holocene sedimentary process and palaeovegetation changes near the mouth of the Amazon River

    Microsoft Academic Search

    José Tasso Felix Guimarães; Marcelo Cancela Lisboa Cohen; Luiz Carlos Ruiz Pessenda; Marlon Carlos França; Clarisse Beltrão Smith; Afonso César Rodrigues Nogueira

    2012-01-01

    The integration of sedimentary facies, pollen, spores, carbon and nitrogen isotopes records, C\\/N ratio and radiocarbon dates allowed the identification of changes in vegetation and the sources of organic matter accumulated on tidal flats near the mouth of the Amazon River during the mid and late Holocene. Data from the margin of Amazon River indicate marine influence related to mangrove

  14. River discharge and flood inundation over the Amazon based on IPCC AR5 scenarios

    NASA Astrophysics Data System (ADS)

    Paiva, Rodrigo; Sorribas, Mino; Jones, Charles; Carvalho, Leila; Melack, John; Bravo, Juan Martin; Beighley, Edward

    2015-04-01

    Climate change and related effects over the hydrologic regime of the Amazon River basin could have major impacts over human and ecological communities, including issues with transportation, flood vulnerability, fisheries and hydropower generation. We examined future changes in discharge and floodplain inundation within the Amazon River basin. We used the hydrological model MGB-IPH (Modelo de Grandes Bacias - Instituto de Pesquisas Hidráulicas) coupled with a 1D river hydrodynamic model simulating water storage over the floodplains. The model was forced using satellite based precipitation from the TRMM 3B42 dataset, and it had a good performance when validated against discharge and stage measurements as well as remotely sensed data, including radar altimetry-based water levels, gravity anomaly-based terrestrial water storage and flood inundation extent. Future scenarios of precipitation and other relevant climatic variables for the 2070 to 2100 time period were taken from five coupled atmosphere-ocean general circulation models (AOGCMs) from IPCC's Fifth Assessment Report (AR5) Coupled Model Intercomparison Project Phase 5 (CMIP5). The climate models were chosen based on their ability to represent the main aspects of recent (1970 to 2000) Amazon climate. A quantile-quantile bias removal procedure was applied to climate model precipitation to mitigate unreliable predictions. The hydrologic model was then forced using past observed climate data altered by delta change factors based on the past and future climate models aiming to estimate projected discharge and floodplain inundation in climate change scenario at several control points in the basin. The climate projections present large uncertainty, especially the precipitation rate, and predictions using different climate models do not agree on the sign of changes on total Amazon flood extent or discharge along the main stem of the Amazon River. However, analyses of results at different regions indicate an increase on flood inundation and discharge over the upper Amazon basin (west Amazon) and decreased discharges over the southeastern tributaries.

  15. Insight on the Peruvian Amazon River: A Planform Metric Characterization of its Morphodynamics

    NASA Astrophysics Data System (ADS)

    Garcia, A. M. P.; Ortals, C.; Frias, C. E.; Abad, J. D.; Vizcarra, J.

    2014-12-01

    Starting in Peru, the Amazon River flows through Colombia and Brazil; additionally, tributaries from Bolivia, Venezuela, and Ecuador contribute to the massive river and its unique geomorphic features. Accordingly, the Amazon Basin has become an important aspect of South America; it is an area of extraordinary biodiversity, rich resources, and unique cultures. However, due to the sheer magnitude and exceptionality of the Amazon River, research regarding the morphodynamic processes that shape and define the river has been difficult. Consequently, current research has not completely understood the planform dynamics of some portions of this river that present a main channel and secondary channels known as "anabranching structures". The purpose of this research was to gain an understanding of the geomorphology of the upper Amazon, the Peruvian section, by obtaining migration rates and planform metrics, including channel count, length, width, and sinuosity, as well as island count, area, and shape. With this data, the morphodynamics of the Peruvian Amazon, especially the relationship between the main channel and its secondary channels in each "anabranching structure" along the river, could be analyzed according to correlations found between various metrics. This analysis was carried out for 5-year time spans over a period of 25 years. Preliminary results showed that the average migration rate versus channel bend radius envelope peak is lower for the secondary channels than for the main channel. However, the maximum migration rate was not always found in the main channel; for several structures, the most dynamic channels were the secondary ones. This implies a certain periodicity to the river's migratory patterns that could be related to the valley boundaries, the local channel sinuosity or geological formations in the study area.

  16. Molecular identification of evolutionarily significant units in the Amazon River dolphin Inia sp. (Cetacea: Iniidae).

    PubMed

    Banguera-Hinestroza, E; Cárdenas, H; Ruiz-García, M; Marmontel, M; Gaitán, E; Vázquez, R; García-Vallejo, F

    2002-01-01

    The Amazon river dolphin, genus Inia, is endemic to the major river basins of northern South America. No previous studies have focused on the genetic structure of this genus. In this work, 96 DNA samples from specimens of this genus were collected in the Orinoco basin (four rivers), the Putumayo River, a tributary of the Colombian Amazon and the Mamoré, and the Tijamuchí and Ipurupuru rivers in theBolivian Amazon. These samples were used to amplify a fragment of 400 bp of the mitochondrial DNA (mtDNA) control region. In addition, 38 of these samples were also used to sequence 600 bp of the mitochondrial cytochrome b gene. The analysis of the population structure subdivision with an analysis of molecular variance (AMOVA) revealed important aspects about the genetic structure of Inia groups fromthese three geographically separate regions. By comparing the control region DNA and cytochrome b sequences, distinct types of nonshared haplotypes were observed. The net genetic divergence of control region sequences was 6.53% between the Orinoco and Bolivian rivers, 5.32% between the Putumayo and Bolivian rivers, and 2.50% between the Orinoco and Putumayo rivers. For the cytochrome b gene, these values were 2.48%, 2.98%, and 0.06%, respectively. The nucleotide sequences were analyzed phylogenetically using several genetic distance matrices and applying neighbor-joining, maximum likelihood, and maximum parsimony procedures. The results support the proposal to subdivide the Inia genus into at least two evolutionarily significant units: one confined to the Bolivian river basin and the other widely distributed across the Amazon and Orinoco basins. PMID:12547919

  17. Depth-integrated suspended sediment and geochemical fluxes in large rivers: the Amazon River system

    NASA Astrophysics Data System (ADS)

    Bouchez, J.; Lupker, M.; Gaillardet, J.; Metivier, F.; France-Lanord, C.; Maurice, L.

    2010-12-01

    Erosion and weathering produce a wide range of residual solid products, in terms of size, density, mineralogy and chemical composition. These solid products are then transported by rivers from the continents to the oceans as suspended particulate matter (SPM) and bedload. Large rivers account for an important part of this transfer of sediments at the global scale. In those rivers, deep channels allow for vertical differentiation, or sorting, of suspended sediment, following their size and density. This hydrodynamic sorting results in vertically heterogeneous depth-profiles in terms of SPM concentration and size distribution (e.g. Garcia, 2008), which in turn likely result in an heterogeneous chemical composition of SPM throughout channel depth (e.g. Galy, 2007), which has to be evaluated. We sampled river water of the main tributaries of the Amazon River system (in the lowland basin), at two distinct water-stages, at various depths following depth-profiles, using a point depth-sampler. After filtration, and SPM recovery, SPM concentration, grain size distribution and chemical composition were determined. River discharge and water velocity throughout the sampled cross-sections were recorded using Acoustic Doppler Current Profiler (ADCP). The large increase in SPM concentration with depth observed at most of the sampled depth-profiles is well accounted for by the Rouse model (e.g. Rouse, 1950). This analysis allows us to reliably infer the SPM concentration and grain size distribution throughout the sampled river cross-section, and thus to estimate the spatially-integrated instantaneous SPM flux using ADCP data (Bouchez et al., 2010). The study also emphasizes the potential role of particle aggregation, within the river system, as a complicating factor regarding the prediction of these depth-integrated SPM fluxes from easily measurable hydrodynamic parameters (surface SPM concentration and grain size, and water velocity). Then, using the previous analysis, combined with the strong correlation between grain size parameters and chemical composition of suspended sediment observed in our set of samples, we deduce the chemical composition of SPM throughout the cross-section, and thus the spatially-integrated chemical fluxes transported as suspended load for a number of elements. These results are finally compared with “simple” estimates relying on the geochemistry of channel surface suspended sediments. This highlights the different behaviors of chemical elements with respect to hydrodynamic sorting in large rivers. References: M.H. Garcia, 2008, Sedimentation engineering: processes, measurements, modeling and practice, EWRI. V. Galy et al., 2007, Nature 450 : 407-411. H. Rouse, 1950, Engineering Hydraulics, Wiley, New York. J. Bouchez et al., 2010, Hydrol. Proc., accepted.

  18. Sediment transport in the Rio Grande, an Andean river of the Bolivian Amazon drainage basin

    Microsoft Academic Search

    JEAN LOUP GUYOT; JACQUES BOURGES; JOSE CORTEZ

    1994-01-01

    The Rio Grande is one of the main Andean tributaries of the Rio Mamore, a tributary of the Rio Madeira which is the main southern affluent of the Amazon. The use of historical (1969-1990) and unpublish­ ed data on sediment transport from 15 Andean gauging stations, made it possible to assess the very strong temporal variability of river sediment-transport. Most

  19. Mercury in Fish-eating Communities of the Andean Amazon, Napo River Valley, Ecuador

    Microsoft Academic Search

    Jena Webb; Nicolas Mainville; Donna Mergler; Marc Lucotte; Oscar Betancourt; Robert Davidson; Edwin Cueva; Edy Quizhpe

    2004-01-01

    This exploratory study aimed to examine the relationship between fish eating habits, human mercury levels, and mercury levels in fish in three communities of the Napo River Valley, Ecuadorian Andean Amazon, a region without gold mining but with significant deforestation and volcanic soils with naturally high mercury levels. By recognizing the politicoeconomic factors which cause deforestation, the cultural factors which

  20. DDT and its metabolites in breast milk from the Madeira River basin in the Amazon, Brazil

    Microsoft Academic Search

    Antonio Azeredo; João P. M. Torres; Márlon de Freitas Fonseca; José Lailson Britto; Wanderley Rodrigues Bastos; Cláudio E. Azevedo e Silva; Giselle Cavalcanti; Rodrigo Ornellas Meire; Paula N. Sarcinelli; Luz Claudio; Steven Markowitz; Olaf Malm

    2008-01-01

    Until the 1990s the 1,1,1-trichloro-bis-2,2?-(4chlorophenyl) ethane (DDT) was sprayed in the walls of the house along the Madeira River basin, Brazilian Amazon, a region well known for its large number of malaria cases. In 1910, Oswaldo Cruz described the presence of malaria in 100% of the population living in some localities from the Madeira River basin. Data available in the

  1. McClain ME, R Galarraga, CA Llerena & JE Ruiz. 2007. Linking Global Change Research to Improved Policies and Management for Rivers: Lessons from the Andean Amazon Rivers Analysis and Monitoring

    E-print Network

    McClain, Michael

    Policies and Management for Rivers: Lessons from the Andean Amazon Rivers Analysis and Monitoring Project and management for rivers: Lessons from the Andean Amazon Rivers Analysis and Monitoring project Michael E. Mc that climate changes will only exacerbate their current development problems (CONAM 2002). Rivers

  2. 2005 drought event in the Amazon River basin as measured by GRACE and estimated by climate models

    Microsoft Academic Search

    J. L. Chen; C. R. Wilson; B. D. Tapley; Z. L. Yang; G. Y. Niu

    2009-01-01

    (1) Satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) provide new quantitative measures of the 2005 extreme drought event in the Amazon river basin, regarded as the worst in over a century. GRACE measures a significant decrease in terrestrial water storage (TWS) in the central Amazon basin in the summer of 2005, relative to the average of

  3. 2005 drought event in the Amazon River basin as measured by GRACE and estimated by climate models

    Microsoft Academic Search

    J. L. Chen; C. R. Wilson; B. D. Tapley; Z. L. Yang; G. Y. Niu

    2009-01-01

    Satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) provide new quantitative measures of the 2005 extreme drought event in the Amazon river basin, regarded as the worst in over a century. GRACE measures a significant decrease in terrestrial water storage (TWS) in the central Amazon basin in the summer of 2005, relative to the average of the

  4. C-13/C-12 of atmospheric CO2 in the Amazon basin - Forest and river sources

    NASA Technical Reports Server (NTRS)

    Quay, Paul; King, Stagg; Wilbur, Dave; Richey, Jeffrey; Wofsy, Steven

    1989-01-01

    Results are presented of measurements of the CO2 concentrations and C-13/C-12 ratios in CO2 in air samples collected from within the Amazonian rain forest and over the Amazon river between 1982 and 1987. Results indicate the presence of a diurnal cycle in the CO2 concentration and the C-13/C-12 ratio. It was found that the CO2 input to air in the forest was derived from the soil respiration, and the CO2 input to air over the Amazon river was derived from the degassing of CO2 from the river. It was also found that plants growing at heights lower than 7 m assimilate soil-derived CO2 with a low C-13/C-12 ratio.

  5. The Amazon river breeze and the local boundary layer. I - Observations

    NASA Technical Reports Server (NTRS)

    De Oliveira, Amauri P.; Fitzjarrald, David R.

    1993-01-01

    Observations of the diurnal evolution of the planetary boundary layer over the Amazon rain forest, made at sites close to the confluence of the Solimoes and Negro rivers (approximately at 3 deg S, 60 deg W) near Manaus, Amazonas, Brazil, show the existence of a diurnal rotation of the wind near the surface and the frequent presence of low-level nocturnal wind maxima. These circulations are shown to be plausibly explained as elements of a river and land breeze circulation induced by the thermal contrast between the rivers and the adjacent forest.

  6. How well does the ERA40 surface water budget compare to observations in the Amazon River basin?

    Microsoft Academic Search

    Kátia Fernandes; Rong Fu; Alan K. Betts

    2008-01-01

    The surface water budget of the Amazon River basin derived from the ERA40 reanalysis is evaluated by comparing it with observed precipitation (P), streamflow\\/runoff (R), and evapotranspiration (ET) data sets for the period of 1980-2002. The rainfall is averaged over 90% of the Amazon River basin, corresponding to the catchments of the Óbidos and Altamira streamflow gauges. The annual rainfall

  7. How well does the ERA40 surface water budget compare to observations in the Amazon River basin?

    Microsoft Academic Search

    Kátia Fernandes; Rong Fu; Alan K. Betts

    2008-01-01

    The surface water budget of the Amazon River basin derived from the ERA40 reanalysis is evaluated by comparing it with observed precipitation (P), streamflow\\/runoff (R), and evapotranspiration (ET) data sets for the period of 1980–2002. The rainfall is averaged over 90% of the Amazon River basin, corresponding to the catchments of the Óbidos and Altamira streamflow gauges. The annual rainfall

  8. Rivers in the sea - Can we quantify pigments in the Amazon and the Orinoco River plumes from space?

    NASA Technical Reports Server (NTRS)

    Muller-Karger, Frank E.; Walsh, John J.; Carder, Kendall L.; Zika, Rod G.

    1989-01-01

    Coastal Zone Color Scanner (CZCS) images of the western tropical Atlantic (1979-1982) were combined into monthly mean surface pigment fields. These suggest that Amazon River water flows along northeastern South America directly toward the Caribbean sea early in the year. After June, however, the North Brazil Current is shunted eastward, carrying a large fraction of Amazon water into the North Equatorial Countercurrent (NECC). This eastward flow causes diminished flow through the Caribbean, which permits northwestward dispersal of Orinoco River water due to local Ekman forcing. The Orinoco plume crosses the Caribbean, leading to seasonal variation in surface salinity near Puerto Rico. At least 50 percent of the pigment concentration estimated in these plumes seems due to viable phytoplankton.

  9. Nest placement of the giant Amazon river turtle, Podocnemis expansa, in the Araguaia River, Goiás State, Brazil.

    PubMed

    Ferreira, Paulo Dias Júnior; Castro, Paulo de Tarso Amorim

    2005-05-01

    The giant Amazon river turtle (Podocnemis expansa) nests on extensive sand bars on the margins and interior of the channel during the dry season. The high concentration of nests in specific points of certain beaches indicates that the selection of nest placement is not random but is related to some geological aspects, such as bar margin inclination and presence of a high, sandy platform. The presence of access channels to high platform points or ramp morphology are decisive factors in the choice of nesting areas. The eroded and escarped margins of the beaches hinder the Amazon river turtle arriving at the most suitable places for nesting. Through the years, changes in beach morphology can alter nest distribution. PMID:16042279

  10. Particulate organic carbon, sterols, fatty acids and pigments in the Amazon River system

    Microsoft Academic Search

    A. Saliot; L. Mejanelle; P. Scribe; J. Fillaux; C. Pepe; A. Jabaud; J. Dagaut

    2001-01-01

    Water samples were collected from the Amazon River system during a high flood period, in June 1989, and lipids associated with particles retained on GF\\/F filters were examined. Particles showed a highly variable organic carbon content (1.8–29.0%). Corresponding organic carbon concentrations varied from 0.36 to 1.13 mg\\/l. The flood conditions encountered during the sampling period may feed exceptional inputs of

  11. Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean

    PubMed Central

    Subramaniam, A.; Yager, P. L.; Carpenter, E. J.; Mahaffey, C.; Björkman, K.; Cooley, S.; Kustka, A. B.; Montoya, J. P.; Sañudo-Wilhelmy, S. A.; Shipe, R.; Capone, D. G.

    2008-01-01

    The fresh water discharged by large rivers such as the Amazon is transported hundreds to thousands of kilometers away from the coast by surface plumes. The nutrients delivered by these river plumes contribute to enhanced primary production in the ocean, and the sinking flux of this new production results in carbon sequestration. Here, we report that the Amazon River plume supports N2 fixation far from the mouth and provides important pathways for sequestration of atmospheric CO2 in the western tropical North Atlantic (WTNA). We calculate that the sinking of carbon fixed by diazotrophs in the plume sequesters 1.7 Tmol of C annually, in addition to the sequestration of 0.6 Tmol of C yr?1 of the new production supported by NO3 delivered by the river. These processes revise our current understanding that the tropical North Atlantic is a source of 2.5 Tmol of C to the atmosphere [Mikaloff-Fletcher SE, et al. (2007) Inverse estimates of the oceanic sources and sinks of natural CO2 and the implied oceanic carbon transport. Global Biogeochem Cycles 21, doi:10.1029/2006GB002751]. The enhancement of N2 fixation and consequent C sequestration by tropical rivers appears to be a global phenomenon that is likely to be influenced by anthropogenic activity and climate change. PMID:18647838

  12. Methane flux from the Amazon River floodplain - Emissions during rising water

    NASA Technical Reports Server (NTRS)

    Bartlett, Karen B.; Crill, Patrick M.; Bonassi, Jose A.; Richey, Jeffrey E.; Harriss, Robert C.

    1990-01-01

    Methane flux data obtained during a period of high and falling water level in the course of the dry season of 1985 (the Amazon Boundary Layer Experiment, ABLE 2A) and a period of moderate and rising water during the wet season of 1987 (ABLE 2B) were used to characterize the influence of seasonal variations in the vegetation, water column depth, and chemistry, as well as atmospheric dynamics, on the methane flux from the Amazon River floodplain. It was found that the annual estimate of methane from wetlands is identical to the annual estimate made by Matthews and Fung (1987) (both at 111 Tg). However, it was found that peatlands between 50 and 70 N contribute 39 Tg, with the large areas of forested and nonforested bogs making up 37 Tg of this figure, while the figures of Matthews and Fung were 63 and 62 Tg, respectively.

  13. Molecular characterization and developmental expression of vitellogenin in the oriental river prawn Macrobrachium nipponense and the effects of RNA interference and eyestalk ablation on ovarian maturation.

    PubMed

    Bai, Hongkun; Qiao, Hui; Li, Fajun; Fu, Hongtuo; Sun, Shengming; Zhang, Wenyi; Jin, Shubo; Gong, Yongsheng; Jiang, Sufei; Xiong, Yiwei

    2015-05-10

    Vitellogenin (Vg) is the precursor of yolk protein, which functions as a nutritive resource that is important for embryonic growth and gonad development. In this study, the cDNA encoding the Vg gene from the oriental river prawn Macrobrachium nipponense was cloned using expressed sequence tag (EST) analysis and the rapid amplification of cDNA ends (RACE) approach. The transcript encoded 2536 amino acids with an estimated molecular mass of 286.810 kDa. Quantitative real-time PCR indicated high expression of Mn-Vg in the female ovary, hemocytes, and hepatopancreas. As ovaries developed, the expression level of Mn-Vg increased in both the hepatopancreas and ovary. In the hepatopancreas, the expression level rose more slowly at the early stage of vitellogenesis and reached the peak more rapidly compared to the expression pattern in ovary. The observed changes in Mn-Vg expression level at different development stages suggest the role of nutrient source in embryonic and larval development. Eyestalk ablation caused the Mn-Vg expression level to increase significantly compared to eyestalk-intact groups during the ovary development stages. Ablation accelerated ovary maturation by removing hormone inhibition of Mn-Vg in the hepatopancreas and ovary. In adult females, Mn-Vg dsRNA injection resulted in decreased expression of Mn-Vg in both the hepatopancreas and ovary, and two injection treatment dramatically delayed ovary maturation. Vg RNA interference down-regulated the vitellogenin receptor (VgR) expression level in the ovary, which illustrates the close relationship between Vg and VgR in the process of vitellogenesis. PMID:25499697

  14. Rivers, refuges and population divergence of fire-eye antbirds (Pyriglena) in the Amazon Basin.

    PubMed

    Maldonado-Coelho, M; Blake, J G; Silveira, L F; Batalha-Filho, H; Ricklefs, R E

    2013-05-01

    The identification of ecological and evolutionary mechanisms that might account for the elevated biotic diversity in tropical forests is a central theme in evolutionary biology. This issue is especially relevant in the Neotropical region, where biological diversity is the highest in the world, but where few studies have been conducted to test factors causing population differentiation and speciation. We used mtDNA sequence data to examine the genetic structure within white-backed fire-eye (Pyriglena leuconota) populations along the Tocantins River valley in the south-eastern Amazon Basin, and we confront the predictions of the river and the Pleistocene refuge hypotheses with patterns of genetic variation observed in these populations. We also investigated whether these patterns reflect the recently detected shift in the course of the Tocantins River. We sampled a total of 32 individuals east of, and 52 individuals west of, the Tocantins River. Coalescent simulations and phylogeographical and population genetics analytical approaches revealed that mtDNA variation observed for fire-eye populations provides little support for the hypothesis that populations were isolated in glacial forest refuges. Instead, our data strongly support a key prediction of the river hypothesis. Our study shows that the Tocantins River has probably been the historical barrier promoting population divergence in fire-eye antbirds. Our results have important implications for a better understanding of the importance of large Amazonian rivers in vertebrate diversification in the Neotropics. PMID:23442128

  15. Regulation of laboratory populations of snails (Biomphalaria and Bulinus spp.) by river prawns, Macrobrachium spp. (Decapoda, Palaemonidae): implications for control of schistosomiasis.

    PubMed

    Sokolow, Susanne H; Lafferty, Kevin D; Kuris, Armand M

    2014-04-01

    Human schistosomiasis is a common parasitic disease endemic in many tropical and subtropical countries. One barrier to achieving long-term control of this disease has been re-infection of treated patients when they swim, bathe, or wade in surface fresh water infested with snails that harbor and release larval parasites. Because some snail species are obligate intermediate hosts of schistosome parasites, removing snails may reduce parasitic larvae in the water, reducing re-infection risk. Here, we evaluate the potential for snail control by predatory freshwater prawns, Macrobrachium rosenbergii and M. vollenhovenii, native to Asia and Africa, respectively. Both prawn species are high value, protein-rich human food commodities, suggesting their cultivation may be beneficial in resource-poor settings where few other disease control options exist. In a series of predation trials in laboratory aquaria, we found both species to be voracious predators of schistosome-susceptible snails, hatchlings, and eggs, even in the presence of alternative food, with sustained average consumption rates of 12% of their body weight per day. Prawns showed a weak preference for Bulinus truncatus over Biomphalaria glabrata snails. Consumption rates were highly predictable based on the ratio of prawn: snail body mass, suggesting satiation-limited predation. Even the smallest prawns tested (0.5-2g) caused snail recruitment failure, despite high snail fecundity. With the World Health Organization turning attention toward schistosomiasis elimination, native prawn cultivation may be a viable snail control strategy that offers a win-win for public health and economic development. PMID:24388955

  16. Riverine Li isotope fractionation in the Amazon River basin controlled by the weathering regimes

    NASA Astrophysics Data System (ADS)

    Dellinger, Mathieu; Gaillardet, Jerome; Bouchez, Julien; Calmels, Damien; Louvat, Pascale; Dosseto, Anthony; Gorge, Caroline; Alanoca, Lucia; Maurice, Laurence

    2015-09-01

    We report Li isotope composition (?7Li) of river-borne dissolved and solid material in the largest River system on Earth, the Amazon River basin, to characterize Li isotope fractionation at a continental scale. The ?7Li in the dissolved load (+1.2‰ to +32‰) is fractionated toward heavy values compared to the inferred bedrock (-1‰ to 5‰) and the suspended sediments (-6.8‰ to -0.5‰) as a result of the preferential incorporation of 6Li into secondary minerals during weathering. Despite having very contrasted weathering and erosion regimes, both Andean headwaters and lowland rivers share similar ranges of dissolved ?7Li (+1.2‰ to +18‰). Correlations between dissolved ?7Li and Li/Na and Li/Mg ratios suggest that the proportion of Li incorporated in secondary minerals during weathering act as the main control on the ?7Lidiss across the entire Amazon basin. A "batch" steady-state fractionation model for Andean and lowland rivers satisfactorily reproduces these variations, with a fractionation factor between weathering products and dissolved load (?sec-dis) of 0.983 ± 0.002. Two types of supply-limited weathering regimes can be identified for the lowlands: "clearwaters" with dominant incorporation of Li in secondary minerals, and "black waters" (e.g., Rio Negro) where dissolution of secondary minerals enhanced by organic matter produces low ?7Li. Apart from the black waters, the ?7Li of Andean and lowland rivers is negatively correlated to the denudation rates with the lowest ?7Li corresponding to the rivers having the highest denudation rates. In contrast, the main tributaries draining both the Andes and the lowlands have higher ?7Li compared to other rivers. We propose that part of the dissolved Li derived from weathering in the Andes is re-incorporated in sediments during transfer of water and sediments in floodplains and that this results in an increase of the dissolved ?7Li along the course of these rivers. Unlike other rivers, the dissolved ?7Li in the main tributaries is best described by a Rayleigh fractionation model with a fractionation factor ?sec-dis of 0.991. Altogether, the control imposed by residence time in the weathering zone and floodplain processes results in (i) a non-linear correlation between dissolved ?7Li and the weathering intensity (defined as W/D) and (ii) a positive relationship between the dissolved Li flux and the denudation rate. These results have important implications for the understanding of past ocean ?7Li and its use as a paleo weathering proxy.

  17. Metagenomics of the Water Column in the Pristine Upper Course of the Amazon River

    PubMed Central

    McMahon, Katherine D.; Toyama, Danyelle; Rinke, Raquel; Cristina Souza de Oliveira, Tereza; Wagner Garcia, José; Pellon de Miranda, Fernando; Henrique-Silva, Flavio

    2011-01-01

    River water is a small percentage of the total freshwater on Earth but represents an essential resource for mankind. Microbes in rivers perform essential ecosystem roles including the mineralization of significant quantities of organic matter originating from terrestrial habitats. The Amazon river in particular is famous for its size and importance in the mobilization of both water and carbon out of its enormous basin. Here we present the first metagenomic study on the microbiota of this river. It presents many features in common with the other freshwater metagenome available (Lake Gatun in Panama) and much less similarity with marine samples. Among the microbial taxa found, the cosmopolitan freshwater acI lineage of the actinobacteria was clearly dominant. Group I Crenarchaea and the freshwater sister group of the marine SAR11 clade, LD12, were found alongside more exclusive and well known freshwater taxa such as Polynucleobacter. A metabolism-centric analysis revealed a disproportionate representation of pathways involved in heterotrophic carbon processing, as compared to those found in marine samples. In particular, these river microbes appear to be specialized in taking up and mineralizing allochthonous carbon derived from plant material. PMID:21915244

  18. Interannual variability in water storage over 2003–2008 in the Amazon Basin from GRACE space gravimetry, in situ river level and precipitation data

    Microsoft Academic Search

    Luciano Xavier; M. Becker; A. Cazenave; L. Longuevergne; W. Llovel; O. C. Rotunno Filho

    2010-01-01

    We investigate the interannual variability over 2003–2008 of different hydrological parameters in the Amazon river basin: (1) vertically-integrated water storage from the GRACE space gravimetry mission, (2) surface water level of the Amazon River and its tributaries from in situ gauge stations, and (3) precipitation. We analyze the spatio-temporal evolution of total water storage from GRACE and in situ river

  19. Transcriptome Analysis of Androgenic Gland for Discovery of Novel Genes from the Oriental River Prawn, Macrobrachium nipponense, Using Illumina Hiseq 2000

    PubMed Central

    Jin, Shubo; Fu, Hongtuo; Zhou, Qiao; Sun, Shengming; Jiang, Sufei; Xiong, Yiwei; Gong, Yongsheng; Qiao, Hui; Zhang, Wenyi

    2013-01-01

    Background The oriental river prawn, Macrobrachium nipponense, is an important aquaculture species in China, even in whole of Asia. The androgenic gland produces hormones that play crucial roles in sexual differentiation to maleness. This study is the first de novo M. nipponense transcriptome analysis using cDNA prepared from mRNA isolated from the androgenic gland. Illumina/Solexa was used for sequencing. Methodology and Principal Finding The total volume of RNA sample was more than 5 ug. We generated 70,853,361 high quality reads after eliminating adapter sequences and filtering out low-quality reads. A total of 78,408 isosequences were obtained by clustering and assembly of the clean reads, producing 57,619 non-redundant transcripts with an average length of 1244.19 bp. In total 70,702 isosequences were matched to the Nr database, additional analyses were performed by GO (33,203), KEGG (17,868), and COG analyses (13,817), identifying the potential genes and their functions. A total of 47 sex-determination related gene families were identified from the M. nipponense androgenic gland transcriptome based on the functional annotation of non-redundant transcripts and comparisons with the published literature. Furthermore, a total of 40 candidate novel genes were found, that may contribute to sex-determination based on their extremely high expression levels in the androgenic compared to other sex glands,. Further, 437 SSRs and 65,535 high-confidence SNPs were identified in this EST dataset from which 14 EST-SSR markers have been isolated. Conclusion Our study provides new sequence information for M. nipponense, which will be the basis for further genetic studies on decapods crustaceans. More importantly, this study dramatically improves understanding of sex-determination mechanisms, and advances sex-determination research in all crustacean species. The huge number of potential SSR and SNP markers isolated from the transcriptome may shed the lights on research in many fields, including the evolution and molecular ecology of Macrobrachium species. PMID:24204682

  20. Transport, distribution and speciation of mercury in the Amazon River at the confluence of black and white waters of the Negro and Solimões Rivers

    Microsoft Academic Search

    Laurence Maurice-Bourgoin; Bernadette Quemerais; Patricia Moreira-Turcq; Patrick Seyler

    2003-01-01

    This study describes the transport and speciation of mercury (Hg) and the associated role of organic matter in these processes at the confluence of the Negro (black waters) and Solimões (white waters) Rivers, which form the Amazon River. The Negro has the highest total Hg content (11·6 to 18·2 ng l-1) due to the extreme particulate Hg concentrations (2074 ng

  1. [Prevalence of arterial hypertension in communities along the Madeira River, Western Brazilian Amazon].

    PubMed

    Oliveira, Beatriz Fátima Alves de; Mourão, Dennys de Souza; Gomes, Núbia; Costa, Janaina Mara C; Souza, Andreia Vasconcelos de; Bastos, Wanderley Rodrigues; Fonseca, Marlon de Freitas; Mariani, Carolina Fiorillo; Abbad, Guilherme; Hacon, Sandra S

    2013-08-01

    The aim of this cross-sectional study was to estimate the prevalence of hypertension among adults (n = 841) in communities along the Madeira River in the Brazilian Amazon, prior to startup of the Santo Antônio Hydroelectric Plant. The study gathered information on sociodemographic conditions, history of diseases, habits, fish consumption, and anthropometric parameters. Logistic regression was used to calculate odds ratios and the respective confidence intervals. Among the riverine communities, 26% (95%CI: 23%-29%) of adults presented hypertension (29% in men [95%CI: 24%-33%] and 23% in women [95%CI: 19%-27%]). Factors associated with hypertension were age, BMI, and place of residence in men and age, triglycerides, and blood glucose in women. The findings can contribute to strategies for state and municipal health services to monitor and prevent cardiovascular events. PMID:24005927

  2. Ontogeny of the plastron of the giant Amazon River turtle, Podocnemis expanse (Schweigger, 1812) (Testudines, Podocnemididae).

    PubMed

    Gonçalves Vieira, Lucélia; Quagliatto Santos, André L; Campos Lima, Fabiano; Souza Pinto, José G

    2009-07-01

    Podocnemis expanse, known popularly as the giant Amazon river turtle, is widely exploited. This makes specimens available for various studies, and we used this opportunity to investigate aspects of the development of the plastron. We examined several stages of pre- and post- hatching development in embryos and hatchlings collected starting from day 18 of natural incubation. Embryos and hatchlings were cleared and double stained for cartilage and bone. The epiplastron, endoplastron, hyoplastron, hypoplastron, xiphiplastron, and mesoplastron bones form the complete plastron of this turtle. In stage 16, bone centers become visible in most of the bones of the plastron. Alizarin Red stain retention indicated that the sequence of bone ossification is as follows: first the hyoplastron and the hypoplastron, then the endoplastron followed by the xiphiplastron, and lastly the mesoplastron. The epiplastron bone shows an ossification center only in stage 20. All these elements have independent ossification centers and join together only later. The plastron closes completely seven months after hatching. PMID:19663644

  3. Old sediment in young rivers- a multiple cosmogenic nuclide study in the Amazon basin

    NASA Astrophysics Data System (ADS)

    Wittmann, Hella; von Blanckenburg, Friedhelm; Maurice, Laurence; Guyot, Jean-Loup; Kubik, Peter

    2010-05-01

    The burial dating technique using in-situ produced cosmogenic isotope pairs (26Al and 10Be) of stationary geomorphic units like terrace deposits has become a valuable tool in deriving sediment deposition chronologies or paleo-denudation rates. In this study, we use 26Al/10Be ratios in detrital sediment from Amazonian rivers to explore the degrees of pre-erosional floodplain burial duration and burial depth as well as degrees of sediment mixing between the active modern rivers and old floodplain reservoirs. 26Al/10Be ratios below a surface production rate ratio of ~6.5 indicate sediment burial, as production of nuclides ceases due to deep shielding in the floodplain and differential decay of 26Al over 10Be causes 26Al/10Be ratios to decrease. Burial depths and durations can be constrained from a modified version of the erosion island plot (26Al/10Be ratio vs. 10Be nuclide concentration diagram) calculated for continuous irradiation during shallow burial. In order to constrain sediment mixing, we analyzed >40 samples for their 26Al/10Be ratios, encompassing the Andean as well as the Guyana and Brazilian Shield headwaters, and the main Amazonian lowland rivers that receive sediment from these differently eroding source areas (Solimões, Amazon, Madeira, Tapajós). The following first-order implications emerge: (i) samples from rapidly denuding Andean headwater streams typically are not affected by burial. (ii) in the Guyana and Brazilian Shield headwaters, average 26Al/10Be ratios are ~5.0, with burial durations between 0.5-1.0 Myr at burial depths around 3 m. (iii) in lowland rivers of central Amazonia that mostly drain the cratonic headwaters (Tapajós, Madeira), coarser grain sizes (> 500 µm) yield 26Al/10Be ratios similar to their cratonic headwaters, whereas finer grain sizes (125-500 µm) reflect the unburied modern stream sediment. (iv) in lowland rivers receiving most sediment from Andean headwaters (Solimões, Amazon), no trend for burial ratio vs. grain size is observable, and typical 26Al/10Be ratios of the main Amazon River are ~5.3, with associated average burial durations of <1 Myr at average depths of ~12 m. Here, also finer grain sizes show deeper burial at ratios <5.0. We observe that when plotted in an erosion island plot, central Amazonian samples evolve along mixing lines between a non-buried Andean end member (represented by modern fluvial sediment produced from hillslope erosion in the source area under continuous cosmic-ray exposure), and a deeply buried end member represented by ~Miocene floodplain sediment. The slope of the mixing lines is hereby a function of the prevailing denudation rate prior burial. For the Miocene floodplain end member, very low burial ratios of ~ 3.0 and long burial durations of ~10 Myr have been measured (Wittmann and von Blanckenburg, 2009). This buried sediment is incorporated into modern, Andean-derived sediment during channel avulsions. Using this dataset, we cannot only constrain the mixing of sediments from different provenances in the classical sense, but can also trace mixing fractions and account for floodplain burial of sediment along the long transfer of sediment from their source areas to the central Amazonian lowlands.(Wittmann, H., and von Blanckenburg, F., 2009, Cosmogenic nuclide budgeting of floodplain sediment transfer: Geomorphology, v. 109, no. 3-4, p. 246-256.)

  4. Pathways of clay mineral transport in the coastal zone of the Brazilian continental shelf from Ceará to the mouth of the Amazon River

    Microsoft Academic Search

    J. O. de Morais; M. Tintelnot; G. Irion; L. Souza Pinheiro

    2006-01-01

    The transport pathways of fine sediments (fraction <2 ?m) along the Brazilian continental shelf from Ceará to the Amazon River\\u000a mouth were studied by means of clay mineral analyses. On the continental shelf southeast of the Amazon mouth, fluctuations\\u000a in clay mineral compositions reflect simple mixing between the suspended load of the North Brazil Current and sediment from\\u000a several smaller rivers.

  5. Seasonal variability in concentration, composition, age, and fluxes of particulate organic carbon exchanged between the floodplain and Amazon River

    NASA Astrophysics Data System (ADS)

    Moreira-Turcq, Patricia; Bonnet, Marie-Paule; Amorim, Marcelo; Bernardes, Marcelo; Lagane, Christelle; Maurice, Laurence; Perez, Marcela; Seyler, Patrick

    2013-01-01

    The composition, sources, and age of particulate organic matter were determined in an Amazonian river-floodplain system during rising, high, falling, and low water periods over 7 yr (1999-2006), and a mass balance for total organic carbon (dissolved and particulate) was estimated. The Curuai floodplain, composed of several temporally interconnected lakes, is permanently connected to the Amazon River via channels. Organic matter (OM) is imported to the floodplain from the Amazon River mainly during the rising water period and produced in the floodplain and exported to the river during high and falling water periods. No significant exchanges occurred during low water periods. The OM produced in the floodplain is characterized by low C/N ratios and by high chlorophyll a concentrations (Chl-a). The ?13C signature has a seasonal trend, with more negative ?13C values during the high water period than other periods. ?14C results indicate that the bulk OM present in floodplain lakes is predominantly post-bomb (i.e., post-1950). Particulate organic carbon (POC) and dissolved organic carbon (DOC) fluxes exported by the Curuai floodplain represent 1.3% and 0.1%, respectively, of the POC and DOC annual fluxes in the mainstem Amazon River at Óbidos but may reach up to 3.3% and 0.8% during falling water. Based on ?14C, ?13C, Chl-a, and elemental analysis of the particulate organic matter, we demonstrate that floodplain lakes have intense phytoplankton and macrophyte primary production, which is partly exported to the main river channel. Floodplains are thus a significant source of modern and labile organic carbon to the river mainstem, where it can be rapidly degraded and recycled back to the atmosphere.

  6. Excitation-emission fluorescence matrix to study pHinfluence on organic matter fluorescence in the Amazon basin rivers

    Microsoft Academic Search

    N. Patel-Sorrentino; S. Mounier; J. Y. Benaim

    2002-01-01

    A study of the three-dimensional excitation-emission fluorescence matrix (EEFM) of organic matter from the Amazon basin rivers is reported in this paper. The EEFM, applied to the fractions obtained from sequential tangential ultrafiltration (STUF), give spectroscopic informations on the fluorescent properties of particulate (>0.22mm), colloidal and dissolved (o5 kD) organic matter. STUF process does not seem to alter the characteristic

  7. Mercury distribution and exchanges between the Amazon River and connected floodplain lakes.

    PubMed

    Maia, Poliana Dutra; Maurice, Laurence; Tessier, Emmanuel; Amouroux, David; Cossa, Daniel; Pérez, Marcela; Moreira-Turcq, Patricia; Rhéault, Isabelle

    2009-11-15

    This work presents the distribution and the partition of mercury (Hg) in the Curuai floodplain lakes along the Amazon River. The maximum Total Filtered Hg (T-FHg) concentrations in the floodplain lakes (28 to 52 pmol L(-1)) coincide with the maximum T-FHg concentrations of the Amazon River and are measured during the flooding period. The lowest T-FHg values (3 to 5 pmol L(-1)) are observed during the flood peak of the mainstream, during the rainy season, when waters are diluted by the local rainfall. In this system, Hg is mainly transported in the particulate phase, confirmed by elevated values of the Hg partition coefficient (4.77

  8. Planform evolution of two anabranching structures in the Upper Peruvian Amazon River

    NASA Astrophysics Data System (ADS)

    Frias, C. E.; Abad, J. D.; Mendoza, A.; Paredes, J.; Ortals, C.; Montoro, H.

    2015-04-01

    We present a study to relate the sinuosity of the main channel and its effect on the dynamics of the secondary channels of anabranching structures. For this purpose, two locations of the Peruvian Amazon River were selected: (1) a site with a medium to high-sinuosity main channel (MS site: Muyuy, Peru) and (2) a site with a low-sinuosity main channel (LS site: at the triple boundary between Brazil, Colombia, and Peru). The main channels for both the MS and LS anabranching structures have freedom to migrate in the lateral direction, while at least one of their secondary channels is adjacent to the geological valley. For MS and LS sites, temporal analysis of planform evolution was carried out using 30 years of satellite imagery from which metrics such as width, sinuosity, and annual maximum migration rates of main and secondary channels were calculated. Additionally, detailed hydrodynamic and bed morphology field measurements were carried out, and a two-dimensional shallow water numerical model was developed. For a medium to high-sinuosity main channel anabranching structure, the secondary channels present a dominant mechanism for reworking the floodplain, while for the low-sinuosity anabranching structure, the main channel planform dynamics is dominant. Flow velocities along the main and secondary channels for low, transition, and high-flow discharges describe that for MS (LS) site, the velocities are much higher along the secondary (main) channels.

  9. Mercury in fish of the Madeira river (temporal and spatial assessment), Brazilian Amazon.

    PubMed

    Bastos, Wanderley R; Dórea, José G; Bernardi, José Vicente E; Lauthartte, Leidiane C; Mussy, Marilia H; Lacerda, Luiz D; Malm, Olaf

    2015-07-01

    The Madeira River is the largest tributary of the Amazon River Basin and one of the most impacted by artisanal gold-mining activities, deforestation for agricultural projects, and recent hydroelectric reservoirs. Total Hg (and methylmercury-MeHg) concentrations was determined in 3182 fish samples of 84 species from different trophic levels as a function of standard size. Species at the top of the trophic level (Piscivorous, Carnivorous) showed the highest mean total Hg concentrations (51-1242µg/kg), Planctivorous and Omnivorous species showed intermediate total Hg concentrations (26-494µg/kg), while Detritivorous and Herbivorous species showed the lowest range of mean total Hg concentrations (9-275µg/kg). Significant correlations between fish size (standard length) and total Hg concentrations were seen for Planctivorous (r=0.474, p=0.0001), Piscivorous (r=0.459, p=0.0001), Detritivorous (r=0.227, p=0.0001), Carnivorous (r=0.212, p=0.0001), and Herbivorous (r=0.156, p=0.01), but not for the Omnivorous species (r=-0.064, p=0.0685). Moreover, fish trophic levels influenced the ratio of MeHg to total Hg (ranged from 70% to 92%). When adjusted for standard body length, significant increases in Hg concentrations in the last 10 years were species specific. Spatial differences, albeit significant for some species, were not consistent with time trends for environmental contamination from past alluvial gold mining activities. Fish-Hg bioaccumulation is species specific but fish feeding strategies are the predominant influence in the fish-Hg bioaccumulation pattern. PMID:25863592

  10. Differentiation in the fertility of Inceptisols as related to land use in the upper Solimões river region, western Amazon.

    PubMed

    Moreira, Fatima Maria de Souza; Nóbrega, Rafaela Simão Abrahão; Jesus, Ederson da Conceição; Ferreira, Daniel Furtado; Pérez, Daniel Vidal

    2009-12-20

    The Upper Solimões river region, western Amazon, is the homeland of indigenous populations and contains small-scale agricultural systems that are important for biodiversity conservation. Although traditional slash-and-burn agriculture is being practiced over many years, deforestation there is relatively small compared to other Amazon regions. Pastures are restricted to the vicinity of cities and do not spread to the small communities along the river. Inceptisols are the main soil order (>90%) in the area and have unique attributes including high Al content and high cation exchange capacity (CEC) due to the enrichment of the clay fraction with 2:1 secondary aluminosilicates. Despite its importance, few studies have focussed on this soil order when considering land use effects on the fertility of Amazon soils. Thus, the objective of this study was to evaluate changes in soil fertility of representative land use systems (LUSs) in the Upper Solimões region, namely: primary rainforest, old secondary forest, young secondary forest, agroforestry, pasture and agriculture. LUSs were significantly differentiated by the chemical attributes of their topsoil (0-20 cm). Secondary forests presented soil chemical attributes more similar to primary rainforest areas, while pastures exhibited the highest dissimilarity from all the other LUSs. As a whole, soil chemical changes among Inceptisols dominated LUSs showed patterns that were distinct from those reported from other Amazon soils like Oxisols and Ultisols. This is probably related to the presence of high-activity clays enriched in exchangeable aluminum that heavily influenced the soil chemical reactions over the expected importance of organic matter found in most studies conducted over Oxisol and Ultisol. PMID:19853281

  11. Metatranscriptomics of N2-fixing cyanobacteria in the Amazon River plume.

    PubMed

    Hilton, Jason A; Satinsky, Brandon M; Doherty, Mary; Zielinski, Brian; Zehr, Jonathan P

    2015-07-01

    Biological N2 fixation is an important nitrogen source for surface ocean microbial communities. However, nearly all information on the diversity and gene expression of organisms responsible for oceanic N2 fixation in the environment has come from targeted approaches that assay only a small number of genes and organisms. Using genomes of diazotrophic cyanobacteria to extract reads from extensive meta-genomic and -transcriptomic libraries, we examined diazotroph diversity and gene expression from the Amazon River plume, an area characterized by salinity and nutrient gradients. Diazotroph genome and transcript sequences were most abundant in the transitional waters compared with lower salinity or oceanic water masses. We were able to distinguish two genetically divergent phylotypes within the Hemiaulus-associated Richelia sequences, which were the most abundant diazotroph sequences in the data set. Photosystem (PS)-II transcripts in Richelia populations were much less abundant than those in Trichodesmium, and transcripts from several Richelia PS-II genes were absent, indicating a prominent role for cyclic electron transport in Richelia. In addition, there were several abundant regulatory transcripts, including one that targets a gene involved in PS-I cyclic electron transport in Richelia. High sequence coverage of the Richelia transcripts, as well as those from Trichodesmium populations, allowed us to identify expressed regions of the genomes that had been overlooked by genome annotations. High-coverage genomic and transcription analysis enabled the characterization of distinct phylotypes within diazotrophic populations, revealed a distinction in a core process between dominant populations and provided evidence for a prominent role for noncoding RNAs in microbial communities. PMID:25514535

  12. Evaluation of monotonic trends for streamflow in austral Amazon, Brazil: a case study for the Xingu and Tapajós rivers

    NASA Astrophysics Data System (ADS)

    Moura, L. Z.

    2015-06-01

    This paper has the goal of evaluating monotonic trends in the Xingu and Tapajós river basins in the Austral Amazon region, Brazil. Non-parametric statistical tests such as Mann-Kendall, Bootstrap Mann-Kendall, Sen and Bootstrap Sen are applied on streamflow gauging stations data, to determine the significance and magnitude of possible trends. Data in these river basins is relatively scarce, with time series ranging from twenty to forty years, having many gaps. Former studies indicate a decreasing trend for both annual average and minimum streamflow values in the Tapajós river basin, with 99% confidence level, and a decrease in maximum values in the Xingu river basin, with 90% confidence level. However, past analyses have only used one station near the basin outlet. This study uses data from 7 gauging stations in the Xingu basin and 14 stations in the Tapajós basin. Results indicate opposite trends at the 95% confidence level for different regions in the basins, and for different flow regimes. For the Xingu river basin, trends in the minimum flow for different sub-basins even out at the Altamira station, near its outlet. For the Tapajós river, the southeastern part of the basin has increasing trends, while the southwestern part decreases. At the Itaituba station, they also balance out.

  13. Decrease of soil fertility and release of mercury following deforestation in the Andean Amazon, Napo River Valley, Ecuador.

    PubMed

    Mainville, N; Webb, J; Lucotte, M; Davidson, R; Betancourt, O; Cueva, E; Mergler, D

    2006-09-01

    Soil erosion and degradation provoked by deforestation in the Amazon is a global concern, and recent studies propose a link between deforestation, soil erosion and the leaching of naturally occurring mercury (Hg). In the Ecuadorian Amazon, elevated deforestation rates and the proximity of volcanoes could play an important role in soil fertility and soil Hg levels. The goal of this study is to evaluate the impacts of deforestation on Andisol and Inceptisol fertility and Hg levels in the Napo River Valley, Ecuador. Results show a significant decrease in surface soil organic matter (-15% to -70% of C and N) and exchangeable cations (-25% to -60%) in deforested plots. Hg concentrations at the surface (0-5 cm), higher in Andisols (225 ng/g average) than in Inceptisols (95 ng/g average), show a decrease of up to 60% following deforestation. Soil erosion exposes the mineral horizon, a layer with a higher Hg burden, to the elements thus provoking and accelerating Hg leaching. These results suggest that deforestation and the associated Hg leaching could contribute to the fish Hg contamination measured in the Napo River watershed. PMID:16499953

  14. Boat-Based Eddy Covariance Measurements of CO2 and H2O Exchange Over Amazon and Tapajos Rivers and Lakes

    NASA Astrophysics Data System (ADS)

    Miller, S.; Freitas, H.; Read, E.; Goulden, M.; Rocha, H.; Doughty, C.

    2004-12-01

    Recent reports suggest that gas evasion of carbon dioxide from the Amazon river and its tributaries to the atmosphere may play an important role in the regional carbon budget. These gas transfer rates were estimated using air-water concentration gradients and gas transfer coefficients (piston velocities) derived from floating chamber measurements. Chamber techniques have inherent uncertainties due to their effect on the near-surface air turbulence. The micrometeorological technique of eddy covariance is attractive since it is a direct measurement of gas exchange and samples over a much larger area. In August 2004, we mounted equipment on a small riverboat to measure CO2 and H2O fluxes from the rivers and lakes near Santarem, Para. The motion of the boat was recorded using an inertial measurement package combined with a GPS receiver, and subtracted from the measured winds. We experimented with both thin-wall Teflon tubing and headspace equilibrators to measure the concentration of CO2 in the water continuously. Our sampling strategy included both "under-way" measurements and stationary (moored) 24-hour measurements on the Amazon and Tapajos rivers, and lakes connected to these rivers. CO2 concentration in the Amazon river and a connected lake was 3000-5000 ppm, much higher than the Tapajos river and a connected lake (range 400-1200 ppm). The "signal-to-noise" ratio was therefore greater for fluxes measured above the Amazon. Preliminary calculations indicate fluxes of order 1-2 micromoles/m2/s over the Amazon and 0.6-1 micromoles/m2/s over the Tapajos, and the calculated gas transfer velocity agrees with existing ocean-based parameterizations.

  15. Methylmercury exposure affects motor performance of a riverine population of the Tapajós river, Brazilian Amazon.

    PubMed

    Dolbec, J; Mergler, D; Sousa Passos, C J; Sousa de Morais, S; Lebel, J

    2000-04-01

    Gold mining and deforestation in the Brazilian Amazon are increasing mercury pollution of the extensive water system, exposing riverine populations to organic mercury through fish-eating. The aim of the present study was to evaluate the effect of such exposure on motor performance. This cross-sectional study was carried out in May 1996, in a village located on the banks of the Tapajós river in the Amazonian Basin, Brazil. Information concerning sociodemographics, health, smoking habits, alcohol drinking, dietary habits and work history were collected using an interview-administered questionnaire. Mercury concentrations were measured by cold vapor atomic absorption in blood and hair of each participant, of whom those aged between 15 and 79 years were assessed for motor performance (n = 84). Psychomotor performance was evaluated using the Santa Ana manual dexterity test, the Grooved Pegboard Fine motor test and the fingertapping motor speed test. Motor strength was measured by dynamometry for grip and pinch strength. Following the exclusion of 16 persons for previous head injury, working with mercury in the goldmining sites, or for diabetes, the relationship between performance and bioindicators of mercury was examined using multivariate statistical analyses, taking into account covariables. All participants in the study reported eating fish, which comprised 61.8% of the total meals eaten during the preceding week. The median hair total mercury concentration was 9 microg/g. Organic mercury accounted for 94.4 = 1.9% of the total mercury levels. Multivariate analysis of variance indicated that hair mercury was inversely associated with overall performance on the psychomotor tests, while a tendency was observed with blood mercury. Semipartial regression analyses showed that hair total mercury accounted for 8% to 16% of the variance of psychomotor performance. Neither hair nor blood total mercury was associated with the results of the strength tests in women and men. Although dose-effect relationships were observed in this cross-sectional study, they may reflect higher exposure levels in the past. The findings of this study demonstrated neurobehavioral manifestations of subtle neurotoxic effects on motor functions, associated with low-level methylmercury exposure. PMID:10787135

  16. Increasing the profitability of traditional, planted rubber agroforests at the Tapajós river, Brazilian Amazon

    Microsoft Academic Search

    G. Schroth; V. H. F. Moraes; M. S. S. da Mota

    2004-01-01

    The planted rubber agroforests of the Tapajós region in eastern Pará State, Brazilian Amazon, are a traditional land use practice of intermediate intensity between extractivism in natural forest and plantation agriculture, and thus of potential interest especially for inhabited conservation areas and Extractive Reserves. We measured rubber production of five groves of 23–40 years of age on representative soil types

  17. Habitat associations of exploited fish species in the Lower Amazon riverfloodplain system

    E-print Network

    Lorenzen, Kai

    Habitat associations of exploited fish species in the Lower Amazon river­floodplain system JOANA the habitat preferences of Amazon fish in order to identify and protect key habitat. The Lower Amazon river

  18. Amazon deforestation alters small stream structure, nitrogen biogeochemistry and connectivity to larger rivers

    Microsoft Academic Search

    Linda A. Deegan; Christopher Neill; Christie L. Haupert; M. Victoria R. Ballester; Alex V. Krusche; Reynaldo L. Victoria; Suzanne M. Thomas; Emily de Moor

    Human activities that modify land cover can alter the structure and biogeochemistry of small streams but these effects are\\u000a poorly known over large regions of the humid tropics where rates of forest clearing are high. We examined how conversion of\\u000a Amazon lowland tropical forest to cattle pasture influenced the physical and chemical structure, organic matter stocks and\\u000a N cycling of

  19. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil.

    PubMed

    Ceddia, Marcos Bacis; Villela, André Luis Oliveira; Pinheiro, Érika Flávia Machado; Wendroth, Ole

    2015-09-01

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0-30 and the 0-100cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80km(2) and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100cm soil depth were 3.28 and 7.32kg C m(-2), respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock. PMID:25918893

  20. Seasonal cycle and interannual variability in the Amazon hydrologic cycle

    E-print Network

    Zeng, Ning

    ], and historical Amazon River discharge. Over a seasonal cycle the precipitation is found to vary by 5 mm d 1­1996. The precipitation lags behind the Southern Oscillation Index by 3­4 months while the Amazon River discharge lags and accuracy [e.g., Xie and Arkin, 1996]. Together with the newly available long-term historical Amazon River

  1. Spatial and temporal rainfall variability near the Amazon-Tapajós confluence

    Microsoft Academic Search

    David R. Fitzjarrald; Ricardo K. Sakai; Osvaldo L. L. Moraes; Raimundo Cosme de Oliveira; Otávio C. Acevedo; Matthew J. Czikowsky; Troy Beldini

    2008-01-01

    Do the influences of river breezes or other mesoscale effects lead to a systematic river proximity bias in Amazon rainfall data? We analyzed rainfall for a network of 38 rain gauges located near the confluence of the Tapajós and Amazon rivers in the eastern Amazon Basin. Tipping bucket rain gauges worked adequately in the Amazon rainfall regime, but careful field

  2. Floodplain hydrology in an Amazon floodplain lake (Lago Grande de Curuai)

    E-print Network

    Boyer, Edmond

    ; accepted 16 October 2007 KEYWORDS Amazon river; Floodplain; River­floodplain interactions; Hydrologic with the Amazon River and its tributaries and these floodplains alter the transport of water and dissolved

  3. Use of Precipitation - Runoff Models to Generate Hydrologic Scenarios in a High-altitude Andean Basin of the Ecuadorian Amazon Region. Case study of the Quijos River Basin.

    NASA Astrophysics Data System (ADS)

    Galarraga, R.; McClain, M.; Ortega, F.; Estacio, A.; Febres, A.

    2007-05-01

    Little is known of the hydrology and meteorology of the expansive Andean Amazon region in South America, which extends for approximately 600.000 Km2 and represents around the 10% of the total Amazon region. Climatic processes that occur in the Andean part of the Amazon influence the middle and lower parts of the Amazon Region. Consequently, there is a need to understand the hydro-climatic characteristics in the high lands of the Andean Amazon. Understanding hydrologic processes in the Andean Amazon is challenged by the lack of hydro meteorological data at all levels. Especially challenging is the absence of data at the appropriate scale for adequate calibration and verification of mathematical models, mainly for understanding precipitation - runoff of high altitude watersheds located on the western most part of the Amazon. The study area is located on the upper part of the Napo River named the Quijos river basin after the junction of the Oyacachi River with a surface area of about 2.500,00 Km2. It is composed mainly of high altitude lands named Paramo, Andean grass lands, primary cloudy forest known for their high water retention and regulatory capacity. The models used in the Quijos river basin in the upper part of the Amazon region of Ecuador are precipitation-runoff models widely used around the world. The Simulator for Water Resources in Rural Basins - Water Quality (SWRRBWQ ) (Arnold et. al. 1990, Williams et. al. 1985), works on a daily time steps basis with daily values of meteorological data both observed in the field or generated by the model, and by sub diving the main basin into a suitable number of sub basins with a meteorological station in it The second model used is the Hydrologic Modeling System from the Hydrologic Engineering Center which is a precipitation - runoff model run at a daily basis as well. Input data sets are basic climate data as precipitation, evapotranspiration, temperature, relative humidity basin wide at daily basis; land cover, soil type, soil characteristics, hydrographic characteristics, as well as registered discharge information in several control points of the basin, that were used for calibration purposes. Several runs of the models were done in order to assess parameter sensibility of the models using appropriate parameter for each case. Calibration for the two models were done for a period where enough information exists even though the time record for verification purposes is well ahead of time so it is assumed that basin wide conditions have not change in time. Three hydrologic scenarios for future discharge prediction based on conservation policies, urbanization, deforestation, or land use change on the area were generated by using HEC-HMS model for the January 1984 - December 1987 period because of its better performance in comparison to the SWRRBWQ model. Scenarios one and two showed almost no difference with the original discharge but scenario three showed an increase in water discharge with time. Results show that in high altitude basins the HEC-HMS performs better than SWRRBWQ model in determining mainly peak discharges but differed in reproducing the total volume of run-off, keeping a good agreement to reproduce seasonality patterns of water discharge. Better information of basin wide characteristics like soil antecedent moisture conditions, land cover, and surface albedo during the calibration period is needed in order to improve model results mainly in volume discharge.

  4. Estimation of mercury wet deposition in the tributary sub-basins of the Negro river (Amazon-Brazil) using RS/GIS tools

    NASA Astrophysics Data System (ADS)

    Jardim, W. F.; Silvério da Silva, G.

    2003-05-01

    Recent studies have shown high concentrations of Hg in fish, soil, lakes and rivers of the Negro river basin. These concentrations were surprisingly high when considering the scarcity of anthropogenic point sources in the region (Fadini and Jardim, 2001). In order to investigate the role of wet deposition in the mercury biogeochemistry cycle in this basin, Hg deposition was estimated for 18 tributary sub-basins of the Negro river, covering an area of nearly 700,000 km2. Mercury wet deposition estimate was done by combining analytical data obtained from total Hg measurements in bulk precipitation (8 measurements between 1997 and 2002), Remote Sensoring (RS) and GIS (Geographie Information System) tools, with the help of orbital images from the JERS-1 SAR project (Global Rain Forest Mapping Project, South America-Amazon Basin), Amazon rainfall map (Sombroek, 2001) and SPRING (Geographie information of processing system) from INPE (Brazilian National Institute of Space Research). For each sub-basin, Hg wet deposition flux (ton km^{-2} yr^{-1}) and the annual amount of Hg (ton yr^{-1}) deposited on the area were estimated. The result allowed a clear picture of each sub-basins, by looking for a relation between the wet deposition, the drainage characteristics of each sub-basin and the Hg concentration in the water column.

  5. Pseudoparasitism by Calodium hepaticum (syn. Capillaria hepatica; Hepaticola hepatica) in the Negro River, Brazilian Amazon.

    PubMed

    Carvalho-Costa, Filipe A; Silva, Adriano Gomes; de Souza, Alberto H; Moreira, Carlos J de C; de Souza, Daniela L; Valverde, Joanna G; Jaeger, Lauren H; Martins, Patrícia P; de Meneses, Viviane F; Araújo, Adauto; Bóia, Márcio N

    2009-10-01

    We report the finding of eggs of Calodium spp. (syn. Capillaria spp.; Hepaticola spp.) in a fecal sample from an old woman living in a riverine community in the Negro River Basin and describe the associated epidemiological investigation. The case probably does not represent true parasitism; the eggs, which were compatible with the species Calodium hepaticum, were most likely ingested upon consumption of infected tapir (Tapirus terrestris) liver, subsequently passing through the gut and being eliminated. The evolution of these eggs to infective stages in the environment, given the poor sanitation background, could provide the risk of occurrence of hepatic disease in humans. PMID:19477475

  6. Post-confluence surface water and sediment distribution patterns of the Solimões-Amazon and Negro Rivers: a remote sensing-based geomorphic study of surface patterns at the large rivers confluences

    NASA Astrophysics Data System (ADS)

    Park, Edward; Latrubesse, Edgardo

    2015-04-01

    River channel confluences are recognized as critical features of the fluvial system, because both intensive and extensive hydro-physical and geo-ecological processes take place within this momentous interface. Despite the relevant findings on confluences as listed above, only a few cases concentrated on field measurements in large rivers. Along with improvements in hydrographic and geochemical surveying techniques, trials have been occasionally made to improve understanding of larger rivers confluences and their downstream hydro-morphodynamics, such as in some reaches of the Amazon, Brahmaputra, Jamuna, and Paraná Rivers. However, finite collections of point-based and cross-sectional measurements obtained from field using acoustic Doppler current profiler (ADCP), multi-beam echo sounder, global positioning system (GPS) or other geochemical applications (e.g. isotope tracing) around river confluences provide limited information of post-confluence hydro-geomorphologic behaviors. The identification of sediment routing through channel junctions and the role of confluence on downstream sediment transport is still poorly understood. Into this context, satellite remote sensing is the most relevant and efficient mean to regularly monitor the river sediment discharge over the large (regional to continental) scale. In this paper, we aim to characterize the spatiotemporal patterns of post-confluence sediment transport by mapping the surface water distribution using the ultimate example of large river confluence on Earth, where distinct water types drain: The Solimões-Amazon (muddy-white water) versus Negro (black water) Rivers, exploring the seasonal and inter-annual variations of water types and the spatial distribution patterns of surface waters through the branches of the main stem.

  7. On the offshore dispersal of the Amazon's Plume in the North Atlantic: Comments on the paper by A. Longhurst, "Seasonal

    E-print Network

    McGillicuddy Jr., Dennis J.

    space. In a recent paper by Longhurst (1993). the plume associated with the Amazon River was attributed plume originates at the Amazon River mouth near the equator, and the other at the Orinoco River mouth

  8. Dams in the Amazon: Belo Monte and Brazil's Hydroelectric Development of the Xingu River Basin

    NASA Astrophysics Data System (ADS)

    Fearnside, Phillip M.

    2006-07-01

    Hydroelectric dams represent major investments and major sources of environmental and social impacts. Powerful forces surround the decision-making process on public investments in the various options for the generation and conservation of electricity. Brazil’s proposed Belo Monte Dam (formerly Kararaô) and its upstream counterpart, the Altamira Dam (better known by its former name of Babaquara) are at the center of controversies on the decision-making process for major infrastructure projects in Amazonia. The Belo Monte Dam by itself would have a small reservoir area (440 km2) and large installed capacity (11, 181.3 MW), but the Altamira/Babaquara Dam that would regulate the flow of the Xingu River (thereby increasing power generation at Belo Monte) would flood a vast area (6140 km2). The great impact of dams provides a powerful reason for Brazil to reassess its current policies that allocate large amounts of energy in the country’s national grid to subsidized aluminum smelting for export. The case of Belo Monte and the five additional dams planned upstream (including the Altamira/Babaquara Dam) indicate the need for Brazil to reform its environmental assessment and licensing system to include the impacts of multiple interdependent projects.

  9. Factors controlling Hg levels in two predatory fish species in the Negro river basin, Brazilian Amazon.

    PubMed

    Belger, Lauren; Forsberg, Bruce Rider

    2006-08-15

    A number of environmental factors have been shown to influence the dynamics of Hg in aquatic ecosystems. Here we investigate the influence of fish size, pH, dissolved organic carbon (DOC), and the availability of potential methylation sites (floodplain forests and hydromorphic soils) on the concentration of total Hg in two carnivorous fishes: Cichla spp. and Hoplias malabaricus in the Negro River, Brazil. Fish and water samples for chemical analysis were collected from 33 sites in the Negro basin. The percentage of alluvial floodplains and hydromorphic soils (potential methylation sites) in the drainage basin upstream from each sampling point was estimated from radar imagery and existing soil maps with GIS. The average of Hg concentrations were 0.337 ppm (SD=0.244) in Cichla spp. and 0.350 ppm (SD=0.250) in H. malabaricus. Although the study area was geographically isolated from most major anthropogenic Hg sources, over 18% of Cichla spp. and 29% of H. malabaricus had Hg concentrations above 0.5 ppm, indicating naturally high background levels of Hg. Hg concentrations increased with size in both Cichla spp. (r(2)=0.664, p=0.000) and H. malabaricus (r(2)=0.299, p=0.000). Hg concentrations in H. malabaricus also increased with percent floodable area (p=0.006), pH (p=0.000) and DOC (0,063). In Cichla spp, Hg increased only in relation to percent floodable area (p=0.000). Hydromorphic soils did not influence fish Hg. PMID:16690103

  10. Trophic Ecology of Frugivorous Fishes in Floodplain forests of the Colombian Amazon 

    E-print Network

    Correa Valencia, Sandra Bibiana

    2012-10-19

    Diverse fish species consume fruits and seeds in the Neotropics, in particular in the lowland reaches of large rivers, such as the Amazon, Orinoco, and Parana in South America. Floodplains of the Amazon River and its ...

  11. Traditionally configured prawn trawls contain small diamond-

    E-print Network

    434 Traditionally configured prawn trawls contain small diamond- shaped meshes in the codend, and small diamond-mesh sections. A strategically located panel of 85-mm netting was inserted on the bar with a conventional diamond-mesh codend (control) showed that both square-mesh designs significantly re- duced

  12. A time series analysis of Prochilodus nigricans landings caught by small-scale fisheries in the lower stretch of the Amazon River.

    PubMed

    Santana, I F; Freitas, C E C

    2013-02-01

    We developed a time series analysis using data on curimatã (Prochilodus nigricans), which landed in Santarém, a small city located on the right banks of the Amazon River. A 10-year record of monthly average catches per day of P. nigricans was analyzed using forecasting procedures in the open-source software GRETL 1.7.8. We established two models from the identifications made with the correlograms of hyperparametrization and seasonal differences. The autoregressive terms of the model reach three years, indicating that individuals of the species are being caught around the age of three. This may indicate that the curimatãs in the landings at Santarém from 1992 to 2002 were more than two years old, potentially a sign of a lack of fishing pressure on the lower age groups. PMID:23644788

  13. (210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil.

    PubMed

    Nery, José Reinaldo Cardoso; Bonotto, Daniel Marcos

    2011-04-01

    Activity profiles of excess (210)Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na(2)O, K(2)O, CaO, MgO, Al(2)O(3), P(2)O(5), Fe(2)O(3) and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm(-2)yr(-1) were obtained, and are compatible with the results of others studies. The (210)Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile. PMID:21353731

  14. Rice-Freshwater Prawn Integrated Culture in Tan Phu Thanh Village, Chau Thanh A district, Can Tho Province

    Microsoft Academic Search

    Nguyen Thanh Phuong; Vu Nam; Vo Thanh Toan; Tran Thi; Thanh Hien; Pham Minh Duc

    Trials of freshwater prawn (Macrobrachium rosenbergii) farming in rice field and garden ditch is being conducted at JIRCAS project research site, Tan Phu Thanh village, Chau Thanh A, Can Tho province. It includes three rice-prawn farms and one garden ditch prawn farm. Juvenile prawns of 0,045 g\\/prawn in average were stocked at a density of 2 prawn\\/m2 in rice-prawn farms,

  15. Sensory Enhancement of Freshwater Prawns Through Post Harvest Salt Acclimation

    Microsoft Academic Search

    M. Wes Schilling; Juan L. Silva; Alessandra J. Pham; Taejo Kim; Louis R. DAbramo; Viodelda Jackson

    2012-01-01

    Freshwater prawns, Macrobrachium rosenbergii, were harvested and transferred to holding tanks containing aerated well water. One group of prawns was held in the well water without any addition of salt (control). For post harvest salt acclimation, experimental treatments consisted of different salt sources (solar, halite, marine) that were initially added to achieve a salinity of 10 ppt. Then 5 ppt

  16. Combining precipitation data from observed and numerical models to forecast precipitation characteristics in sparsely-gauged watersheds: an application to the Amazon River basin.

    NASA Astrophysics Data System (ADS)

    Dwelle, M. C.; Ivanov, V. Y.; Berrocal, V.

    2014-12-01

    Forecasting rainfall in areas with sparse monitoring efforts is critical to making inferences about the health of ecosystems and built environments. Recent advances in scientific computing have allowed forecasting and climate models to increase their spatial and temporal resolution. Combined with observed point precipitation from monitoring stations, these models can be used to inform dynamic spatial statistical models for precipitation using methods from geostatistics and machine learning. To prove the feasibility, process, and capabilities of these statistical models, we present a case study of two statistical models of precipitation for the Amazon River basin from 2003-2010 that can infer a spatial process at a point using areal data from numerical model output. We investigate the seasonality and accumulation of rainfall, and the occurrence of no-rainfall and large-rainfall events. These parameters are used since they provide valuable information on possible model biases when using climate models for forecasts of the future process of precipitation in the Amazon basin. This information can be vital for ecosystem, agriculture, and water-resource management. We use observed precipitation data from weather stations, three areal datasets derived from observed precipitation (CFSR, CMORPH-CRT, GPCC) and three climate model precipitation datasets from CMIP5 (MIROC4h, HadGEM2-CC, and GISS-E2H) to construct the models. The observational data in the model domain is sparse, with 195 stations in the approximate 7×106 square kilometers of the Amazon basin, and therefore requires the areal data to create a more robust model. The first model uses the method of Bayesian melding to combine and make inferences from the included data sets, and the second uses a regression model with spatially and temporally-varying coefficients. The models of precipitation are fitted using the areal products and a subset of the point data, while another subset of point data is held out for verification. The statistical models are evaluated based on the predictive performance using metrics such as mean absolute errors and coverage of predictive intervals. Precipitation estimates from the climate models are also evaluated on the basis of their performance in analyzing the accumulation, seasonality, and occurrence of rainfall.

  17. Physical oceanography of the Amazon shelf

    Microsoft Academic Search

    W. Rockwell Geyer; Robert C. Beardsley; Steven J. Lentz; Julio Candela; Richard Limeburner; William E. Johns; Belmiro M. Castro; Ivan Dias Soares

    1996-01-01

    The Amazon shelf is subject to energetic forcing from a number of different sources, including near-resonant semi-diurnal tides, large buoyancy flux from the Amazon River discharge, wind stress from the northeasterly tradewinds and strong along-shelf flow associated with the North Brazil Current. Although the large volume of river discharge produces a pronounced salinity anomaly, the water motions on the shelf

  18. TITLE: Seasonal and spatial variability of CO2 emission from a large floodplain lake in the1 lower Amazon2

    E-print Network

    California at Santa Barbara, University of

    of the Amazon River in four hydrological phases. We calculated surficial17 CO2 concentrations from measurements Amazon River23 inflows. CO2 concentration was reduced in regions with phytoplankton blooms. The range of].51 The annual flood of the Amazon River influences the ecology and biogeochemistry52 within its floodplain

  19. Water quality changes in floodplain lakes due to the Amazon River flood pulse: Lago Grande de Curuaí (Pará).

    PubMed

    Affonso, A G; Barbosa, C; Novo, E M L M

    2011-08-01

    Assurance of water quality for human consumption is essential for public health policies. In the Amazon floodplain, the seasonal water level variation causes periodic flooding of marginal areas that are usually used for settlements, agriculture and livestock. Therefore, the exchange of materials between the terrestrial and aquatic ecosystem affects the proportion of suspended and dissolved components in water and its physical-chemical characteristics, and consequently the quality of the water used by local people. Following this approach, the aim of this study is to evaluate changes in water quality in Lago Grande de Curuaí floodplain, Óbidos, Pará in response to the flood pulse, during one hydrological year from 2003 to 2004, based on water use classes (according to National Water Agency 357/2005 resolution) using chlorophyll-a and dissolved oxygen concentration as parameters and the eutrophication index. Ordinary kriging was applied to interpolate chlorophyll-a and dissolved oxygen and to predict values at non sampled locations. Each location was then classified according to water use acceptable parameters and to Carlson Trophic State Index modified by Toledo to map lake water classes and trophic status. The result showed that Lago Grande de Curuaí floodplain is a supereutrophic system, with levels of dissolved oxygen and chlorophyll-a not suitable for human supply during the receding water phase. These areas are located near the riverine communities, which can cause health problems due to the presence of potentially toxic algae. Therefore, monitoring water quality in Amazon lakes is essential to ensure the availability has appropriate quality for human and animal supplies. PMID:21881783

  20. Geothermal aquaculture: a guide to freshwater prawn culture

    SciTech Connect

    Hayes, A.; Johnson, W.C.

    1980-05-01

    Biological data of the Malaysian prawn, Macrobrachium rosenbergii, are summarized. A history on its rearing techniques is given, but through the use of geothermal water or industrial warm water effluent, its range can be expanded. The use of wasted geothermal water at the Oregon Institute of Technology for prawn ponds is noted. Pond management and design; the hatchery design and function for larval culture; and geothermal applications (legal aspects and constraints) are discussed. (MCW)

  1. [Diet and reproduction of the main fish species from the Mesay river (Colombian Amazon region) during the flooding season].

    PubMed

    Blanco-Parra, María del Pilar; Bejarano-Rodríguez, Ivonne

    2006-09-01

    The diet and reproduction of fish communities in three biotopes (river, stream, and lake) of the Mesay floodplain-river complex (Puerto Abeja, Serrania de Chiribiquete National Natural Park, Caquetá, Colombia) were sampled during the "high water" level or flooding period. A total of 79 species of fishes from 15 families and four orders were collected between July and September 2000. The most important items in their diet were fruits and seeds. Approximately 46 % of captured fish were near maturity, and 35 % were mature. The feeding and reproductive behavior of these fish were consistent with other studies on migratory Amazonian species during the high water period, when the floodplain plays an important role in the availability of food and refuge. During this period the fish make use of the vast food availability to accumulate fat reserves that later produce the energy needed for gonadal maturation and breeding migrations. PMID:18491626

  2. Routine Metabolic Rate and Limiting Oxygen Concentration of Freshwater Prawn Macrobrachium rosenbergii Larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malaysian prawns, Macrobrachium rosenbergii, are hatched and raised indoors in small tanks. Prawns may be raised and shipped at high densities which could result in low dissolved oxygen (DO) conditions. Because DO may play an important role in prawn development and survival, we measured routine me...

  3. Chemical weathering and atmospheric\\/soil CO 2 uptake in the Andean and Foreland Amazon basins

    Microsoft Academic Search

    Jean-Sébastien Moquet; Alain Crave; Jérôme Viers; Patrick Seyler; Elisa Armijos; Luc Bourrel; Eduardo Chavarri; Christelle Lagane; Alain Laraque; Waldo Sven Lavado Casimiro; Rodrigo Pombosa; Luis Noriega; Andrea Vera; Jean-Loup Guyot

    2011-01-01

    This study is a geochemical investigation of the Andean and Foreland basins of the Amazon River at high spatial and time resolution, carried out within the framework of the HYBAM research program (Hydro-geodynamics of the Amazon Basin). Monthly sampling was carried out at 27 gauging stations located in the upper tributaries of the Amazon Basin (from north to south: the

  4. Solar aquaculture: A wintering technique for parent prawns

    SciTech Connect

    Cao Jin Long [Aquaculture Res. Inst., Shandong Province (China)

    1994-09-01

    A new method of providing the warm water needed for parent prawn wintering using solar energy is described. Using solar energy for prawn wintering involves heat collection, heat storage and temperature maintenance. The system designed provides sufficient energy for the safe wintering of prawns with suitable water temperatures. The temperature control facilities consist of three parts: a salt gradient solar pond, a shallow solar pond and a plastic house. The technique involves use of a shallow solar pond for collection and storage of heat. The average temperature in the wintering pond plastic house was 11 degrees C and the minimum temperature in January was 5.4 degrees C. This system allowed the wintering process to be conducted using solar energy alone and may extend aquaculture to higher latitudes. The ratio of net profit with the solar energy system over investment is 1.5 which makes it economically viable.

  5. ULTRASTRUCTURE OF THE PRAWN NERVE SHEATHS

    PubMed Central

    Doggenweiler, C. F.; Heuser, John E.

    1967-01-01

    The sheaths from freshly teased nerve fibers of the prawn exhibit a positive radial birefringence, consistent with their EM appearance as highly organized laminated structures composed of numerous thin cytoplasmic sheets or laminae bordered by unit membranes and arranged concentrically around the axon. The closely apposed membranes in these sheaths are fragile and often break down into rows of vesicles during fixation. Desmosome-like attachment zones occur in many regions of the sheath. The membranes within these zones resist vesiculation and thereby provide a "control" region for relating the type of vesicles formed in the fragile portions of the sheaths to the specific fixation conditions. It is proposed that during fixation the production of artifactual vesicles is governed by an interplay of three factors: (a) direct chemical action of the fixative on the polar strata of adjacent unit membranes, (b) osmotic forces applied to membranes during fixation, and (c) the pre-existing natural relations between adjacent membranes. It is found that permanganate best preserves the continuity of the membranes but will still produce vesicles if the fixative exerts severe osmotic forces. These results support other reports (19) of the importance of comparing tissues fixed by complementary procedures so that systematic artifacts will not be described as characteristic of the natural state. PMID:4166578

  6. The {sup 18}O:{sup 16}O of dissolved oxygen in rivers and lakes in the Amazon Basin: Determining the ratio of respiration to photosynthesis rates in freshwaters

    SciTech Connect

    Quay, P.D.; Wilbur, D.O.; Richey, J.E. [Univ. of Washington, Seattle, WA (United States)] [and others

    1995-06-01

    The concentration and {sup 18}O:{sup 16}O ratio of dissolved oxygen were measured for 23 rivers and lakes of the Amazon Basin during 1988, 1990, and 1991. With only two exceptions, the rivers and lakes had dissolved oxygen concentrations that were at 20-90% of atmospheric saturation levels. The {delta}{sup 18}O of the dissolved oxygen ranged from 15 to 30% (vs. SMOW). The {delta}{sup 18}O for the lakes were the lowest at 15-23%. {delta}{sup 18}O < 24.2{per_thousand} (the atmospheric equilibrium value) are the result of photosynthetic oxygen input. The {delta}{sup 18}O of the rivers, in contrast, ranged from 24 to 30{per_thousand} > 24.2{per_thousand} resulted from respiration. Despite this clear difference between the {delta}{sup 18}O for rivers and lakes, these water bodies had similar levels of oxygen undersaturation. The {delta}{sup 18}O and dissolved oxygen concentrations are used to determine the ratio of community respiration (R) to gross photosynthesis (P) rates. R:P varied between {approximately}1 and 1.5 for lakes and between 1.5 and 4 for rivers. For all rivers and lakes, the measured {delta}{sup 18}O indicated the presence of photosynthetically produced oxygen, with the highest proportion occurring in lakes. The {delta}{sup 18}O of dissolved oxygen is a unique tracer of photosynthetic oxygen and provides, through a determination of R:P, a means of quantifying the heterotrophic state of freshwaters. 29 refs., 8 figs., 4 tabs.

  7. Biology of penaeid prawns in the Suez Canal lakes

    Microsoft Academic Search

    A. A.-F. A. Gab-Alla; R. G. Hartnoll; A.-F. Ghobashy; S. Z. Mohammed

    1990-01-01

    A study was made from January 1988 to March 1989 of the penaid prawns in the Great Bitter Lake and Lake Timsah located in the central part of the Suez Canal. Two species of Red Sea origin were investigated,Metapenaeus stebbingi andTrachypenaeus curvirostris; the former is by far the commoner. Both species displayed seasonal breeding over the period April to October,

  8. Volatile components associated with bacterial spoilage of tropical prawns.

    PubMed

    Chinivasagam, H N; Bremner, H A; Wood, A F; Nottingham, S M

    1998-06-30

    Analysis of headspace volatiles by gas chromatography/mass spectrometry from king (Penaeus plebejus), banana (P. merguiensis), tiger (P. esculentus/semisulcatus) and greasy (Metapenaeus bennettae) prawns stored in ice or ice slurry, which is effectively an environment of low oxygen tension, indicated the presence of amines at the early stages of storage (less than 8 days) irrespective of the nature of the storage media. Esters were more prevalent in prawns stored on ice (normal oxygen conditions) at the latter stages of storage (more than 8 days) and were only produced by Pseudomonas fragi, whereas sulphides and amines occurred whether the predominant spoilage organism was Ps. fragi or Shewanella putrefaciens. The free amino acid profiles of banana and king prawns were high in arginine (12-14%) and low in cysteine (0.1-0.17%) and methionine (0.1-0.2%). Filter sterilised raw banana prawn broth inoculated with a total of 15 cultures of Ps. fragi and S. putrefaciens and incubated for two weeks at 5 degrees C, showed the presence of 17 major compounds in the headspace volatiles analysed using gas chromatography/mass spectrometry (GC/MS). These were mainly amines, sulphides, ketones and esters. Principal Component Analysis of the results for the comparative levels of the volatiles produced by pure cultures, inoculated into sterile prawn broth, indicated three subgroupings of the organisms; I, Ps. fragi from a particular geographic location; II, S. putrefaciens from another geographic location; and III, a mixture of Ps. fragi and S. putrefaciens from different geographic locations. The sensory impression created by the cultures was strongly related to the chemical profile as determined by GC/MS. Organisms, even within the same subgrouping classified as identical by the usual tests, produced a different range of volatiles in the same uniform substrate. PMID:9706797

  9. Effect of cadmium on the ovarian development in the freshwater prawn Macrobrachium rosenbergii (De Man).

    PubMed

    Revathi, Peranandam; Vasanthi, Lourduraj Arockia; Munuswamy, Natesan

    2011-05-01

    In this investigation, effect of cadmium chloride (25 ?g/l) on oogenesis of freshwater prawn, Macrobrachium rosenbergii was studied. In vivo experiments were performed with both intact and eyestalk ablated prawns. The intact, cadmium-exposed prawns exhibited decrease in Gonado Somatic Index (GSI) and ovarian development compared to controls. Whereas, ablated treated ovary showed reduction of yolk material and oocyte membrane thickness at the end of 15 days exposure. Interestingly, the control prawn showed normal cellular architecture of gills, hepatopancreas and ovary with mature oocytes. But, the gills of treated prawns showed lamellar hypertrophy, cuticular dystrophy and irregular arrangement of epithelial cells. Hepatopancreas showed reduction in both tubular diameter and basement membrane thickness. Conspicuously, ovary showed hypertrophied primary oocytes with more vacuoles in intact-treated group. Cadmium had increased gonad inhibiting hormone (GIH) secretion and decreased gonad stimulating hormone (GSH) release as evident with the retardation of gonadal maturation in the intact prawns. PMID:21296420

  10. Gene Expression in Black Tiger Prawns Following Intramuscular Injection of ?-gal Plasmid

    Microsoft Academic Search

    Z. H. Sulaiman; R. H. Ming Chan; P. M. Simanjuntak

    1999-01-01

    Gene expression in black tiger prawns (Penaeus monodon) was studied following intra-muscular injection of CMVßGal plasmid into the second abdominal segment. We used an in situ staining technique to detect ß-gal expression in one- and three-month-old injected prawns. We found that only one of the three-month-old prawns expressed the marker gene (2 days after injection), and the site of expression

  11. Uranium in river water

    Microsoft Academic Search

    M. R. Palmer; J. M. Edmond

    1993-01-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains

  12. Elevated mercury concentrations in soils, sediments, water, and fish of the Madeira River basin, Brazilian Amazon: a function of natural enrichments?

    Microsoft Academic Search

    P. j. Lechler; J. r. Miller; L. d. Lacerda; D. Vinson; J.-C Bonzongo; W. b. Lyons; J. j. Warwick

    2000-01-01

    Previous site-specific investigations have found that mercury concentrations in water, sediments, and biota of the Brazilian Amazon are elevated above global averages, and that these concentrations are a direct result of widespread mercury amalgamation mining operations conducted by non-organized prospectors. In order to assess the regional impacts of Hg contamination from these non-organized gold mining activities, water, sediments, and fish

  13. The impact of global positioning systems and plotters on fishing power in the northern prawn fishery, Australia

    Microsoft Academic Search

    Carolyn M. Robins; You-Gan Wang; David Die

    1998-01-01

    The impact of global positioning systems (GPS) and plotter systems on the relative fishing power of the northern prawn fishery fleet on tiger prawns (Penaeus esculentus Haswell, 1879, and P. semisulcatus de Haan, 1850) was investigated from commercial catch data. A generalized linear model was used to account for differences in fishing power between boats and changes in prawn abundance.

  14. Spoilage Pattern of Five Species of Australian Prawns

    Microsoft Academic Search

    H. Nalini Chinivasagam; H. Allan Bremner; Stephen J. Thrower; Stephen M. Nottingham

    1996-01-01

    Five species of commercial prawns Penaeus plebejus, P. merguiensis, P. semisulcatus\\/P. esculentus and M. bennettae, were obtained from South-East and North Queensland, chilled soon after capture and then stored either whole or deheaded on ice and ice slurry, until spoilage. Total bacterial counts, total volatile nitrogen, K-values and total demerit scores were assessed at regular intervals. Their shelf lives ranged

  15. The status of infectious disease in the Amazon region.

    PubMed

    Tauil, Pedro Luiz

    2009-04-01

    The Amazon River basin region is a vast territory with an area >7 million km2, encompassing parts of 9 South American countries: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. The Amazon River, the longest river in the world, traverses the region from west to east, fed by multiple tributaries. The region also contains the largest tropical rainforest in the world, situated on a massive plain whose altitude is near sea level. With a climate characterized by high temperatures and humidity and copious rainfall, the region has the densest and most varied ecosystem in the world. PMID:19331757

  16. Hydrology and climate in the southwestern Amazon basin (Bolivia)

    Microsoft Academic Search

    J. Ronchail; L. Bourrel; L. Maurice-Bourgoin; P. Vauchel; G. Cochonneau; J. L. Guyot; L. Phillips; A. Castro

    2003-01-01

    The variability of the runoff of the Bolivian tributaries of the Madeira River, the greatest southern affluent of the Amazon R., is of major importance for the riparian people safety and for the economic development of the region. We investigated whether the discharge of these rivers is predictable or not, using the Sea Surface Temperatures Anomalies (SSTAs) in the Equatorial

  17. The "Prawn-in-the-Tube" Procedure in the Cuttlefish: Habituation or Passive Avoidance Learning?

    ERIC Educational Resources Information Center

    Dickel, Ludovic; Chichery, Marie-Paule; Agin, Veronique; Chichery, Raymond

    2006-01-01

    This study examines whether or not habituation contributes to the regulation of the inhibition of predatory behavior observed during the "prawn-in-the-tube" training procedure. When presented with prawns that are visible behind glass but untouchable, cuttlefish promptly learn to inhibit their capture attempts. The first three experiments…

  18. Management strategies for short lived species: The case of Australia's Northern Prawn Fishery

    Microsoft Academic Search

    Catherine M. Dichmont; André E. Punt; William Venables; Malcolm Haddon

    2006-01-01

    Management strategies for tiger prawns, Penaeus semisulcatus and P. esculentus, in Australia's Northern Prawn Fishery (NPF), are evaluated in terms of conservation- and economic-related performance measures. A two-stage process is used to determine the factors to which these performance measures are most sensitive. The first stage involves identifying the possible factors and their interactions, constructing a partial factorial design to

  19. Experiments on seed production and commercial culture of the freshwater prawn (Macrobrachium nipponense)

    Microsoft Academic Search

    Nguyen Quoc An; Phan Dinh Phuc; Phan Thi Le Anh; Nguyen Thi Tu; Ly Ngoc Tuyen; Le Phuoc

    Aquaculture of the freshwater prawn Macrobrachium nipponense has potential to develop into a high value enterprise. However, this commercial development faces the constraints of insufficient stocking material and a lack of suitable culture technology. This paper presents preliminary results of experiments designed to address these two problems. The experiments on prawn seed production used eight small (each 2 m2 in

  20. Studies on the Functional Morphology and Ecology of the Atyid Prawns of Dominica

    Microsoft Academic Search

    G. Fryer

    1977-01-01

    Six species of atyid prawns, representing five genera, occur in streams on the West Indian island of Dominica (figures 1-0). The ecology and habits of each are described and the relation of features of gross morphology to ways of life noted. Xiphocaris elongata, the most primitive living atyid, is a lightly built prawn whose adult habits are related to life

  1. GBR-prawn: modelling ecosystem impacts of changes in fisheries management of the commercial prawn (shrimp) trawl fishery in the far northern Great Barrier Reef

    Microsoft Academic Search

    Neil A Gribble

    2003-01-01

    GBR-prawn is a “mass-balance” trophic-based ecosystem model (ECOPATH II) of the Great Barrier Reef, which combines a model template of a generalised coral reef ecosystem with results from extensive cross-shelf surveys of the far northern Great Barrier Reef. The enhanced model includes both the trawl and line fisheries, but focuses on the effect of trawling on the penaeid prawn community

  2. In: Biology, Evolution and Conservation of River Dolphins... ISBN 978-60876-633-8 Editors: Manuel Ruiz-Garcia and Joseph Shostell 2010 Nova Science Publishers, Inc.

    E-print Network

    Solé-Cava, Antonio M.

    as in the Amazon River basin (Figure 1). Marine Sotalia are found from Honduras to the state of Santa Catarina and Colombia) and "lam" (Nicaragua). The distribution of riverine Sotalia comprises most of the Amazon River

  3. The JERS Amazon Multi-Season Mapping Study (JAMMS): Observation Strategies and Data Characteristics

    NASA Technical Reports Server (NTRS)

    Chapman, B.; Freeman, A.; Siqueira, P.

    2000-01-01

    The JERS-1 Amazon Multi-season Mapping Study (JAMMS), part of the Global Rain Forest Mapping (GRFM) project led by the National Space Development Agency of Japan (NASDA), had an ambitious agenda to completely map the Amazon River floodpain (and surrounding areas) twice at high resolution.

  4. Water buffalo and cattle ranching in the Lower Amazon Basin: Comparisons and conflicts

    Microsoft Academic Search

    Pervaze A. Sheikh; Frank D. Merry; David G. McGrath

    2006-01-01

    From 1975 to 2000, the water buffalo population in the Brazilian Amazon increased at nearly 13% per year, making it one of the fastest growing herds in the world. On the floodplains of the Amazon River buffalo are managed in a similar manner to cattle, but often earn superior production figures. This production advantage, however, is tempered by the role

  5. White Tail Disease of Freshwater Prawn, Macrobrachium rosenbergii.

    PubMed

    Sahul Hameed, A S; Bonami, Jean-Robert

    2012-09-01

    Macrobrachium rosenbergii is the most important cultured freshwater prawn in the world and it is now farmed on a large scale in many countries. Generally, freshwater prawn is considered to be tolerant to diseases but a disease of viral origin is responsible for severe mortalities in larval, post-larval and juvenile stages of prawn. This viral infection namely white tail disease (WTD) was reported in the island of Guadeloupe in 1995 and later in Martinique (FrenchWest Indies) in Taiwan, the People's Republic of China, India, Thailand, Australia and Malaysia. Two viruses, Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus-like particle (XSV) have been identified as causative agents of WTD. MrNV is a small icosahedral non-enveloped particle, 26-27 nm in diameter, identified in the cytoplasm of connective cells. XSV is also an icosahedral virus and 15 nm in diameter. Clinical signs observed in the infected animals include lethargy, opaqueness of the abdominal muscle, degeneration of the telson and uropods, and up to 100 % within 4 days. The available diagnostic methods to detect WTD include RT-PCR, dot-blot hybridization, in situ hybridization and ELISA. In experimental infection, these viruses caused 100 % mortality in post-larvae but failed to cause mortality in adult prawns. The reported hosts for these viruses include marine shrimp, Artemia and aquatic insects. Experiments were carried out to determine the possibility of vertical transmission of MrNV and XSV in M. rosenbergii. The results indicate that WTD may be transferred from infected brooders to their offspring during spawning. Replication of MrNV and XSV was investigated in apparently healthy C6/36 Aedes albopictus and SSN-1 cell lines. The results revealed that C6/36 and SSN-1cells were susceptible to these viruses. No work has been carried out on control and prevention of WTD and dsRNA against protein B2 produced RNAi that was able to functionally prevent and reduce mortality in WTD-infected redclaw crayfish. PMID:23997437

  6. Fortified versus incurred residues: extraction of furazolidinone metabolite from prawn.

    PubMed

    Johnston, Lesley; Croft, Meg; Murby, John

    2015-06-01

    Most methods reported in the literature for determination of nitrofuran metabolites use the same extraction and derivatisation conditions to hydrolyse and extract the protein-bound residues from animal tissue. While undertaking certification of reference materials for nitrofuran metabolites in freeze-dried prawn, it was found that these conditions are satisfactory for recovery of spiked residues; however, extraction efficiencies of incurred furazolidinone could be substantially increased by further optimisation of the extraction conditions. The availability of a suitable certified reference material allows laboratories to ensure that their method is optimised for incurred residues. PMID:25862475

  7. Rivers

    NSDL National Science Digital Library

    2011-08-15

    This video segment from IdahoPTV's D4K takes you on a trip down Idaho's Snake River near 1000 Springs and Blur Heart Springs while it explains how rivers are formed, their uses, and how they make valleys, canyons and even plains.

  8. Mercury and flooding cycles in the Tapajós River basin, Brazilian Amazon: the role of periphyton of a floating macrophyte (Paspalum repens).

    PubMed

    Coelho-Souza, Sérgio A; Guimarães, Jean R D; Miranda, Márcio R; Poirier, Hugo; Mauro, Jane B N; Lucotte, Marc; Mergler, Donna

    2011-06-15

    Methylmercury (MeHg) increases mercury (Hg) toxicity and is biomagnified in the trophic chain contaminating riverine Amazon populations. Freshwater macrophyte roots are a main site of Hg methylation in different Brazilian environments. Paspalum repens periphyton was sampled in four floodplain lakes during the dry, rainy and wet seasons for measurement of total Hg (THg), MeHg, Hg methylation potentials, %C, %N, ?(13)C, ?(15)N and bacterial heterotrophic production as (3)H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me(203)Hg formation was expressive (1-23%) showing that periphyton is an important matrix both in the accumulation of Hg and in MeHg production. The concentration of MeHg varied from 1 to 6 ng/g DW and was positively correlated with Me(203)Hg formation. Though methylmercury formation is mainly a bacterial process, no significant correlation was observed between the methylation potentials and bacterial production. The multiple regressions analyses suggested a negative correlation between THg and %C and %N and between methylation potential and ?(13)C. The discriminant analysis showed a significant difference in periphyton ?(15)N, ?(13)C and THg between seasons, where the rainy season presented higher ?(15)N and the wet period lighter ?(13)C, lower THg values and higher Me(203)Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. PMID:21536317

  9. The Hydrological Modeling and Analysis Platform (HyMAP): Evaluation in the Amazon Basin

    E-print Network

    Paris-Sud XI, Université de

    that the model can satisfactorily simulate the large-scale features of the water surface dynamics of the Amazon River basin. Among all stream gauges considered, 23% have Nash­Sutcliffe co- efficients (NS) higher than

  10. Flooding and carbon dynamics on the lower Amazon floodplain

    NASA Astrophysics Data System (ADS)

    Rudorff, Conrado de Moraes

    The Amazon basin stores and cycles large quantities of water and carbon, and floodplains are an important part of these processes. In this dissertation, I studied the interactions of hydrological and biogeochemical processes over a large floodplain unit in the eastern Amazon, the Curuai floodplain. I combined digital topography derived from the Shuttle Radar Topography Mission with extensive echo-sounding data to generate a hydraulically correct digital elevation model. Floodplain inundation was simulated over a period of 15 years (1995-2010) using LISFLOOD-FP, which combines one-dimensional river routing with two-dimensional overland flow, and a local hydrological model. An accurate filling and drainage of the floodplain was achieved with quantification of changes in water elevation, flooding extent, and river-floodplain flows. Levee height and channel topography were the main controls of river-floodplain exchanges during high and low-water, respectively. The inflow from the Amazon River corresponded to 82% of annual inputs from all sources, with dominant sources of inflow varying seasonally among direct rain and local runoff (November), Amazon River (December through August) and groundwater seepage (September and October). A water balance analysis and concentrations and transformations of carbon from other studies on the central Amazon floodplain were used to compute the fluxes through the major pathways of carbon loss from the Curuai floodplain. Carbon dioxide outgassing represented 86% of the total carbon loss and its seasonal and spatial variability was further investigated. The seasonal changes in lake mixing patterns exerted an important control over both carbon dioxide production and gas transfer velocities. The range of spatial variation in carbon dioxide concentration was least at low water and largest at high water. Gas transfer coefficients that take into account both wind and heat fluxes at the lake's surface were approximately four times higher than values previously used in regional estimates of gas evasion from lakes on the Amazon floodplain.

  11. Monitoring water level in large trans-boundary ungauged basins with altimetry: the example of ENVISAT over the Amazon basin

    Microsoft Academic Search

    Frederique Seyler; Stephane Calmant; Joecila da Silva; Naziano Filizola; Emmanuel Roux; Gerard Cochonneau; Philippe Vauchel; Marie-Paule Bonnet

    2009-01-01

    Brasil and Bolivia have water plans projects on the Beni-Madeira river, a major tributary of the Amazon. There are four main tributaries to the Rio Madeira: the Guapore, the Mamore and the Beni rivers into the Bolivian territory, and the Madre de Dios River crossing the North of Bolivia, coming from Peru. Most parts of these rivers are very far

  12. Improvement of red color development on the surface of kuruma prawn Marsupenaeus japonicus under various conditions.

    PubMed

    Ando, Masashi; Fukai, Takamitsu; Kawasaki, Ken-Ichi; Itoh, Tomohiro; Tsukamasa, Yasuyuki

    2014-02-01

    The degree of red color development on the surface of prawns by cooking is an important index for food quality. In this study, we tested several factors that are thought to influence the red color development to identify possible correlations with various conditions. Live kuruma prawns, Marsupenaeus japonicus, (15.4 cm, 25.2 g on average) were used in this study. In case of cooking at 100 °C for 1 min after 24 h of storage at 0 °C, 5 °C, and 20 °C, the red color development rate of prawns stored at 5 °C and 20 °C was significantly lower than that of prawns cooked just after killing. In case of cooking at 100 °C, 80 °C, and 60 °C after storage for 24 h at 0 °C, there was no color development at 60 °C and significantly less color development at 80 °C compared to cooking just after killing. Preparation using 1% sodium carbonate before cooking at 80 °C could compensate for the lack of red color development. Short exposure of live kuruma prawns to low-oxygen conditions had no influence on the color development, but putting the prawns in freshwater for 3 h significantly reduced the red color development rate. In conclusion, the storage time has little influence on the red color development when the cooking temperature is sufficiently high. However, in case a large amount of prawns is cooked followed by lowering the cooking temperature and/or prawns are exposed to serious stresses before cooking, an alkaline preparation could compensate for the lack of red color development. PMID:24456388

  13. Monitoring acoustically tagged king prawns Penaeus ( Melicertus ) plebejus in an estuarine lagoon

    Microsoft Academic Search

    Matthew D. Taylor; Anthony Ko

    2011-01-01

    Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use,\\u000a foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat\\u000a use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23

  14. Biochemical Stress Responses in Tissues of the Prawn Macrobrachium malcolmsonii on Exposure to Endosulfan

    Microsoft Academic Search

    P. Saravana Bhavan; P. Geraldine

    2001-01-01

    This study was conducted to investigate the induction of biochemical stress responses in Macrobrachium malcolmsonii following exposure to endosulfan and to determine the most sensitive parameter of endosulfan-induced stress in this species of prawn. Intermolt juvenile prawns were exposed to three sublethal concentrations of endosulfan (10.6, 16.0, and 32.0 ng\\/L) for a period of 21 days. Samples were taken from

  15. Histopathology of the hepatopancreas and gills of the prawn Macrobrachium malcolmsonii exposed to endosulfan

    Microsoft Academic Search

    P Saravana Bhavan; P Geraldine

    2000-01-01

    The tissue damage induced by various organic pollutants in aquatic animals is well-documented, but there is a dearth of information relating to the histological alterations induced by pesticides in freshwater prawns of the genus Macrobrachium. In the present study intermoult juveniles of the freshwater prawn Macrobrachium malcolmsonii (total length, 4.5–5.0 cm; weight, 1.0–1.25 g) were exposed to three sublethal concentrations

  16. Expressed sequence tags from eyestalk of kuruma prawn, Marsupenaeus japonicus.

    PubMed

    Yamano, Keisuke; Unuma, Tatsuya

    2006-02-01

    We analyzed the expressed sequence tags (ESTs) obtained from a cDNA library of the eyestalk of the kuruma prawn, Marsupenaeus japonicus, to examine gene expression profile with special focus on female reproduction. The assembly of 1988 ESTs created 136 contigs from 738 ESTs; however 1250 ESTs remained singletons. Significant similarities (blast score > or = 50 bits) to the DNA sequences in the databank were found for only 16.7% of the 1386 sequences (136 contigs plus 1250 singletons), suggesting that the eyestalk library contains many unknown genes. Ribosomal RNA and mitochondrial respiration enzymes with significant similarities were found abundantly in the ESTs, whereas genes related to maturation or endocrine systems were scarce. Three ESTs were assumed to encode novel eyestalk hormones with marked similarities to pigment-dispersing hormone, molt-inhibiting hormone and crustacean hyperglycemic hormone. Sequences encoding a product highly homologous to farnesoic acid O-methyltransferase, an enzyme that produces methyl farnesoate, were also found. PMID:16406641

  17. Development of regional future climate change scenarios in South America using the Eta CPTEC/HadCM3 climate change projections: climatology and regional analyses for the Amazon, São Francisco and the Paraná River basins

    NASA Astrophysics Data System (ADS)

    Marengo, Jose A.; Chou, Sin Chan; Kay, Gillian; Alves, Lincoln M.; Pesquero, José F.; Soares, Wagner R.; Santos, Daniel C.; Lyra, André A.; Sueiro, Gustavo; Betts, Richard; Chagas, Diego J.; Gomes, Jorge L.; Bustamante, Josiane F.; Tavares, Priscila

    2012-05-01

    The objective of this study is to assess the climate projections over South America using the Eta-CPTEC regional model driven by four members of an ensemble of the Met Office Hadley Centre Global Coupled climate model HadCM3. The global model ensemble was run over the twenty-first century according to the SRES A1B emissions scenario, but with each member having a different climate sensitivity. The four members selected to drive the Eta-CPTEC model span the sensitivity range in the global model ensemble. The Eta-CPTEC model nested in these lateral boundary conditions was configured with a 40-km grid size and was run over 1961-1990 to represent baseline climate, and 2011-2100 to simulate possible future changes. Results presented here focus on austral summer and winter climate of 2011-2040, 2041-2070 and 2071-2100 periods, for South America and for three major river basins in Brazil. Projections of changes in upper and low-level circulation and the mean sea level pressure (SLP) fields simulate a pattern of weakening of the tropical circulation and strengthening of the subtropical circulation, marked by intensification at the surface of the Chaco Low and the subtropical highs. Strong warming (4-6°C) of continental South America increases the temperature gradient between continental South America and the South Atlantic. This leads to stronger SLP gradients between continent and oceans, and to changes in moisture transport and rainfall. Large rainfall reductions are simulated in Amazonia and Northeast Brazil (reaching up to 40%), and rainfall increases around the northern coast of Peru and Ecuador and in southeastern South America, reaching up to 30% in northern Argentina. All changes are more intense after 2040. The Precipitation-Evaporation (P-E) difference in the A1B downscaled scenario suggest water deficits and river runoff reductions in the eastern Amazon and São Francisco Basin, making these regions susceptible to drier conditions and droughts in the future.

  18. In-Depth Tanscriptomic Analysis on Giant Freshwater Prawns

    PubMed Central

    Mohd-Shamsudin, Maizatul Izzah; Kang, Yi; Lili, Zhao; Tan, Tian Tian; Kwong, Qi Bin; Liu, Hang; Zhang, Guojie; Othman, Rofina Yasmin; Bhassu, Subha

    2013-01-01

    Gene discovery in the Malaysian giant freshwater prawn (Macrobrachium rosenbergii) has been limited to small scale data collection, despite great interest in various research fields related to the commercial significance of this species. Next generation sequencing technologies that have been developed recently and enabled whole transcriptome sequencing (RNA-seq), have allowed generation of large scale functional genomics data sets in a shorter time than was previously possible. Using this technology, transcriptome sequencing of three tissue types: hepatopancreas, gill and muscle, has been undertaken to generate functional genomics data for M. rosenbergii at a massive scale. De novo assembly of 75-bp paired end Ilumina reads has generated 102,230 unigenes. Sequence homology search and in silico prediction have identified known and novel protein coding candidate genes (?24%), non-coding RNA, and repetitive elements in the transcriptome. Potential markers consisting of simple sequence repeats associated with known protein coding genes have been successfully identified. Using KEGG pathway enrichment, differentially expressed genes in different tissues were systematically represented. The functions of gill and hepatopancreas in the context of neuroactive regulation, metabolism, reproduction, environmental stress and disease responses are described and support relevant experimental studies conducted previously in M. rosenbergii and other crustaceans. This large scale gene discovery represents the most extensive transcriptome data for freshwater prawn. Comparison with model organisms has paved the path to address the possible conserved biological entities shared between vertebrates and crustaceans. The functional genomics resources generated from this study provide the basis for constructing hypotheses for future molecular research in the freshwater shrimp. PMID:23734171

  19. Sources and sinks of sediment to the Amazon margin: The Amapa coast

    NASA Astrophysics Data System (ADS)

    Allison, M. A.; Nittrouer, C. A.; Faria, L. E. C.; Silveira, O. M.; Mendes, A. C.

    1996-03-01

    Modern and Holocene muddy strata were studied along the shoreline adjacent to the Amazon river mouth using sedimentological, radiochemical, physical, and seismic methods. The present paper is a synthesis of the results, collected during the AmasSeds project, that is used to outline a regional shoreline sediment budget. Erosion of relict Amazon muds in southern Amapa supplies 106 tons yr-1 to the Amazon advective mud stream. Local rivers are sediment-poor (total suspended discharge ~ 1 × 106 tons yr-1), but form depositional sandflats on the shoreface downdrift of the river mouths. Mudflat accumulation in northern Amapa sequesters 106 107 tons yr-1 by tidal-flat aggradation, alongshore mudcape accretion, and sediment trapping by mangroves. The processes temporarily store 1.5 × 108 tons of Amazon mud in January June.

  20. Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity

    PubMed Central

    Finer, Matt; Jenkins, Clinton N.

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics. PMID:22529979

  1. Challenges and Opportunities for Co-Management of a Migratory Fish (Prochilodus nigricans) in the Peruvian Amazon

    Microsoft Academic Search

    Mariana Montoya

    Fisheries co-management lies at the center of environmental, social, and economic issues in the lower Pastaza River basin in the Peruvian Amazon. In this remote region, the intermingling of black and white water systems creates unique aquatic habi- tats that harbor diverse assemblages of fishes, including Prochilodus nigricans, a migratory species of high ecological and socioeconomic importance throughout the Amazon.

  2. Effects of different feeding regimes on ovarian maturation and spawning of pond-reared giant tiger prawn in Thailand

    Microsoft Academic Search

    Sakon Sangpradub; Arlo W. Fast; Somkiat Piyatiratitivorakul; Piamsak Menasveta

    1994-01-01

    Large pond-reared Penaeus monodon were used in three maturation and spawning trials lasting 60 days. One group of prawns was fed a fresh diet only; a second group was supplied a fresh diet combined with a formulated pelleted diet; a third group of prawns received the formulated diet only. Total maturation (N = 66 and 55) and spawning events (N

  3. Genetic diversity of cultured and wild populations of the freshwater prawn Macrobrachium rosenbergii based on microsatellite analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Freshwater prawn Macrobrachium rosenbergii culture in the Western Hemisphere is primarily, if not entirely, based on thirty-six individual prawn introduced to Hawaii from Malaysia in 1965 and 1966. Little information is available regarding the genetic background or current population status of cult...

  4. Acute effects of deltamethrin on swimming velocity and biomarkers of the common prawn Palaemon serratus.

    PubMed

    Oliveira, Cristiana; Almeida, Joana; Guilhermino, Lúcia; Soares, Amadeu M V M; Gravato, Carlos

    2012-11-15

    The main purpose of the present study was to investigate the effects of deltamethrin on biomarkers and behavior of Palaemon serratus (common prawn), since this attempt to link different levels of biological organization will allow determining which biomarkers might be ecologically relevant and will be useful to complement the information about the effects of pesticides by using behavioral parameters. Therefore, parameters of liver antioxidant status, energy metabolism and neurotransmission were determined in different tissues of the common prawn and used to assess the effects at sub-individual level, whereas swimming velocity was used to assess the effects at the individual level. It was also investigated if the swimming velocity can be used as an endpoint in ecotoxicology bioassays and if it can be as sensitive as biomarker endpoints. Swimming velocity was significantly reduced in prawns exposed to deltamethrin, showing a lowest observed effect (LOEC) of 0.6 ng L(-1). Eye acetylcholinesterase (AChE) activity was significantly increased in prawns exposed to 0.6, 1.2 and 2.4 ng L(-1) deltamethrin, whereas muscle cholinesterase (ChE) activity was significantly increased in prawns exposed to 19 and 39 ng L(-1). On the other hand, lactate dehydrogenase (LDH) activity was significantly increased in muscle of prawns exposed to 0.6, 1.2, 2.4, 4.9 ng L(-1) deltamethrin, showing that organisms were requiring additional energy, but probably using it for detoxification processes rather than locomotion, since swimming velocity was inhibited. Glutathione S-transferase (GST) activity was significantly increased in the digestive gland of common prawn exposed to 19 and 39 ng L(-1) deltamethrin. Catalase (CAT) activity was significantly increased in digestive gland of prawn exposed to 19 ng L(-1) deltamethrin. However, CAT activity decreased in digestive gland of prawn exposed to 39 ng L(-1), suggesting an antioxidant defense system failure concomitant with high levels of lipid peroxidation. Thus, global results showed that decreased swimming velocity was not associated with cholinesterase inhibition. In fact, the impairment of swimming velocity may be due to allocation of energy for detoxification and antioxidant protection instead of swimming activity. The present study showed that swimming velocity could be used as an ecologically relevant tool and a sensitive endpoint to assess and complement the study of pesticide effects on marine organisms. PMID:22967730

  5. Peroxinectin gene transcription of the giant freshwater prawn Macrobrachium rosenbergii under intrinsic, immunostimulant, and chemotherapeutant influences.

    PubMed

    Liu, Chun-Hung; Yeh, Shinn-Pyng; Hsu, Pei-Yi; Cheng, Winton

    2007-04-01

    Peroxinectin (PE) gene expressions were determined using real-time PCR in the giant freshwater prawn Macrobrachium rosenbergii based on moulting; prawns were fed diets containing different concentrations of sodium alginate, and were exposed to different concentrations of copper sulphate, benzalkonium chloride (BKC), and trichlorfon. Results showed that PE mRNA expression of prawns was the highest in stage A, significantly decreased in stage B, and reached the lowest level in stages D0/D1. The PE transcript was significantly higher in prawns fed the 1.0 gkg(-1) sodium alginate-containing diet than those fed the 2.0 gkg(-1) sodium alginate-containing diet and those fed the control diet. PE transcripts significantly decreased in prawns exposed to 0.1-0.4 mgL(-1) copper sulphate after 96 h, 0.3-1.0 mgL(-1) BKC after 96 h, and 0.2-0.4 mgL(-1) trichlorfon after 48 h. It was concluded that the status of PE gene expression was seriously affected by the moult cycle, immunostimulant, and chemotherapeutants. PMID:17056274

  6. The Amazon and climate

    NASA Technical Reports Server (NTRS)

    Nobre, C. A.

    1984-01-01

    The climatologies of cloudiness and precipitation for the Amazon, are reviewed and the physical causes of some of the observed features and those which are not well known are explained. The atmospheric circulation over the Amazon is discussed on the large scale tropical circulations forced by deep diabatic heating sources. Weather deforestation which leads to a reduction in evapotranspiration into the atmosphere, and a reduction in precipitation and its implicated for the gobal climate is discussed. It is indicated that a large scale clearing of tropical rainforests there would be a reduction in rainfall which would have global effects on climate and weather both in the tropical and extratropical regions.

  7. Potential groundwater contribution to Amazon evapotranspiration

    NASA Astrophysics Data System (ADS)

    Fan, Y.; Miguez-Macho, G.

    2010-07-01

    Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations show enhanced growth in response to higher radiation under less cloudy skies, indicating an adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution). Here we assess the importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of water table depth from observations and groundwater modeling, and a map of potential capillary flux these water table depths can sustain. The maps show that the water table beneath the Amazon can be quite shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia). The water table can potentially sustain a capillary flux of >2.1 mm day-1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day-1 across nine study sites. Current models simulate a large-scale reduction in dry-season photosynthesis under today's climate and a possible dieback under projected future climate with a longer dry season, converting the Amazon from a net carbon sink to a source and accelerating warming. The inclusion of groundwater and capillary flux may modify the model results.

  8. Inundation, Wetland Vegetation and Biogeochemical Processes in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Melack, J. M.; Hess, L. L.; Hamilton, S. K.; Richey, J. E.; Novo, E. M.

    2001-12-01

    Remote sensing of the Amazon basin with passive and active microwave techniques were applied to determine the temporally varying extent of inundation and associated vegetation, and used in conjunction with field measurements to calculate regional rates of carbon dioxide emission from wetlands to the atmosphere. Monthly inundation areas were derived from analysis of the 37-GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer (1979 to 1987) for the mainstem Amazon floodplain in Brazil, the Llanos de Moxos (Beni and Mamore rivers) in Bolivia, the Bananal Island (Araguaia River) and Roraima savannas. Maximum areas subject to inundation, including permanent open waters in rivers and lakes, were as follows (in km2): mainstem Amazon 97,400; Moxos 92,000; Bananal 58,500, and Roraima 16,500. Data from the Japanese Earth Resources Satellite-1, L-band synthetic aperture radar were used to determine inundation and wetland vegetation for a quadrat in the central Amazon basin (0o N to 8o S, 72o W to 54o W) at high water (May-June 1996) and low water (October 1995). Flooded area of rivers and floodplains (> 100 m in width) ranged from 79,000 km2 to 290,000 km2. When combined with estimates of inundation associated with streams not detected by the radar, a maximum area of 350,000 km2 (or 20% of the quadrat) was flooded. Combining the areal extent of flooding and measurements of free dissolved CO2 with an evasion model leads to outgassing of CO2 from inundated surfaces to the atmosphere in the central Amazon of 1.1 plus or minus 0.2 MgC ha-1 y-1. Extrapolated over the whole basin, the flux is 10 times the fluvial export of organic carbon to the ocean.

  9. Phosphamidon, methylparathion and dichlorvos impact on tissue oxidative metabolism in penaeid prawn, Metapenaeus monoceros.

    PubMed

    Reddy, M S; Rao, K V

    1991-02-01

    Changes in oxidative metabolism of hepatopancreas and muscle tissues of penaeid prawn, Metapenaeus monoceros was studied, following its exposure to selected organophosphorous insecticides phosphamidon, dichlorovos and methylparathion. The OPI are found to inhibit the activity levels of acetylcholinesterase, succinate dehydrogenase, isocitrate dehydrogenase, pyruvate dehydrogenase, lactate dehydrogenase and cytochrome-c-oxidase and cause accumulation of acetylcholine in the hepatopancreas and muscle tissues. These changes in the activity levels of selected oxidative enzymes during insecticide exposure in these tissues of prawn indicates the shift in the metabolic emphasis from aerobic to anaerobic conditions and is interpreted as a functional adaptation to insecticide induced metabolic stress. These observed changes at cellular level pave way for successful survival of prawns in insecticide polluted environ. PMID:1877982

  10. Methylparathion, carbaryl and aldrin impact on nitrogen metabolism of prawn, Penaeus indicus.

    PubMed

    Reddy, M S; Rao, K V

    1991-01-01

    Changes in hepatopancreas, muscle and gill tissue nitrogen metabolic profiles were studied in a penaeid prawn, Penaeus indicus, following its exposure to sublethal concentrations of methylparathion, carbaryl and aldrin. In all the insecticide exposed prawn tissues, Ammonia levels were significantly increased and a shift in the nitrogen metabolism towards the synthesis of urea and glutamine was observed. Inhibition of glutamate oxidation to ammonia and alpha-ketoglutarate by glutamate dehydrogenase suggests a mechanism whereby hyperammonemia is reduced by minimizing the addition of further ammonia to the already existing elevated ammonia pool. Increased alanine and aspartate aminotransferases demonstrates the onset of gluconeogenesis. Mechanisms to detoxify the ammonia by enhancing the synthesis of urea and glutamine at the cellular level was observed in the selected tissues pave way for the survivability of prawns in insecticide polluted environs. PMID:1907140

  11. Identification and cloning of a selenium dependent glutathione peroxidase from giant freshwater prawn, Macrobrachium rosenbergii.

    PubMed

    Yeh, Shinn-Pyng; Liu, Kuan-Fu; Chiu, Shieh-Tsung; Jian, Shun-Ji; Cheng, Winton; Liu, Chun-Hung

    2009-08-01

    A selenium dependent glutathione peroxidase (Se-GPx) cDNA was cloned from haemocyte by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA (RACE). The 913 bp cDNA contained an open reading frame (ORF) of 558 bp encoded a deduced amino acid sequence of 186 amino acids. The prawn Se-GPx sequence contains a selenocysteine (Sec) residue which is encoded by the unusual stop codon, (115)TGA(117). According to the molecular modeling analysis, the active site Sec residue, located in the loop between beta3 and alpha2 in a pocket on the protein surface, and hydrogen bonded to Gln(73) and Trp(141). A GPx signature motif 2, (63)LAFPCNQF(70) and active site motif, (151)WNFEKF(156), two arginine (R) residues, R(89) and R(167) contribute to the electrostatic architecture that directs the glutathione donor substrate, and two putative N-glycosylation site, (75)NNT(77) and (107)NGS(109) were observed in the prawn Se-GPx sequence. In addition, the eukaryotic selenocysteine insertion sequence element is conserved in the 3'-UTR. Comparison of amino acid sequences showed that prawn Se-GPx is more closely related to vertebrate GPx 1. The prawn Se-GPx was synthesized in haemocyte, hepatopancreas, muscle, stomach, gill, intestine, eyestalk, heart, epidermis, lymph organ, ventral nerve cord, testis and ovary. The increase of respiratory burst in haemocyte was observed in pathogen, Debaryomyces hansenii-injected prawn in order to kill the pathogen, and the up-regulation in SOD and GPx acitivity, and prawn Se-GPx mRNA transcription were involved with the protection against damage from oxidation. PMID:19376233

  12. Glutathione S-transferase and metallothionein levels in the freshwater prawn Macrobrachium malcolmsonhi exposed to mercury.

    PubMed

    Yamuna, A; Bhavan, P Saravana; Geraldine, P

    2012-01-01

    Healthy juveniles of M. malcolmsoniiwere exposed to 24.1 microg l(-1) of mercury (96 hr LC50: 145 microg l(-1) Hg) for a period of 21 days. The hepatopancreas and gills of the prawns were sampled on 8th, 15th and 22nd day of exposure. Accumulation and elimination of Hg, activity of glutathione S-transferase (GST), content of glutathione (GSH) and metallothionein (MT) level were studied. Mercury accumulation was found to be higher in the hepatopancreas (88.60 microg g(-1)) and lower in the gills (67.8 microg g(-1)). However, Hg elimination was found to be faster in the gills (62%) and slower in the hepatopancreas (58%). Therefore, the rate of Hg elimination did not match the rate of its uptake. The activity of GST was found to be higher in tissues of test prawns (5.94-9.13 nmol mg(-1) protein min(-1)) on all sampling days when compared with controls (3.454.23 nmol mg(-1) protein min(-1)). Similarly, the content of GSH was found to be higher in tissues of test prawns (0.80-1.43 micromol g(-1) protein) on all sampling days when compared with controls (0.55-1.00 micromol g(-1) protein). These results indicate the formation of glutathione conjugate in test prawns to eliminate Hg. The induction of MT level was also found to be higher in tissues of test prawns (57.50-75.76 nmol g(-1) protein) on all sampling days when compared with control (20.24-45.22 nmol g(-1) protein). This indicates the fact that sequestration of Hg has occurred for its easy elimination. Thus, induction of GST-GSH and MT ensured protection and adaptation of test prawns to thrive in Hg contaminated environment. PMID:23033656

  13. Dopaminergic modulation of neuromuscular transmission in the prawn.

    PubMed Central

    Miller, M W; Parnas, H; Parnas, I

    1985-01-01

    The action of the putative crustacean neurohormone dopamine was examined in the fast extensor musculature of the prawn with intracellular and extracellular recording techniques. Dopamine produced a concentration-dependent (10(-7)-10(-5) M) decrease in the size of the excitatory junctional potential (e.j.p.). It had no effect on the muscle fibre resting membrane potential or input resistance. High concentrations (10(-5)M) of dopamine had no effect on the amplitude distribution or decay time of quantal unit currents, indicating that the agent does not act by blocking post-synaptic receptors or channels. Bath application of dopamine reduced the quantal content at single release sites with a similar time course and concentration dependence as that observed for the e.j.p. Dopamine had no effect on histograms of synaptic delays determined over a 10 degree C range, indicating that it does not modify the time course of phasic neurosecretion. Twin-impulse facilitation experiments showed a marked decrease in the duration of facilitation in the presence of dopamine. These results are interpreted according to recent theoretical and experimental findings as indicating that the dopamine-induced reduction in transmitter release is produced by a decrease in the entry of Ca during the nerve terminal action potential. PMID:2862279

  14. Rivers of Destiny

    NSDL National Science Digital Library

    These summaries and video excerpts examine the health of four river systems - the Mississippi, the Amazon, the Jordan and the Mekong, and how environmental problems are facing those who depend on them. There is an account of the flooding in Grafton, Illinois in 1993, one of many towns to suffer devastating damage when the upper Mississippi River overflowed its banks. The video excerpts are from the "Journey to Planet Earth" television series; each is approximately three minutes in length.

  15. The increase of immunity and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii by feeding with selenium enriched-diet.

    PubMed

    Chiu, Shieh-Tsung; Hsieh, Shu-Ling; Yeh, Shinn-Pyng; Jian, Shun-Ji; Cheng, Winton; Liu, Chun-Hung

    2010-10-01

    The effects of inorganic selenium (Se) (sodium selenate, SSe) and organic selenium (seleno-l-methionine, MSe) supplementation on the immune response, antioxidant status, and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii, were studied. Five experimental diets, including a control diet (without Se enrichment), 0.5 mg (kg diet)(-1) of MSe, 1 mg (kg diet)(-1) of MSe, 0.5 mg (kg diet)(-1) of SSe, and 1 mg (kg diet)(-1) of SSe, were used. After 75 days of culture, prawn fed the Se-enriched diets had lower mortality compared to that of prawn fed the control diet after being challenged by the pathogen, Debaryomyces hansenii. No significant differences in the total hemocyte count, superoxide dismutase activity, or clearance efficiency of prawn were recorded among the control and treated groups. Significantly increased phenoloxidase and phagocytic activities in prawn fed the Se-enriched diets were found compared to the controls. Respiratory bursts of prawn fed both forms of 1 mg Se (kg diet)(-1) significantly increased compared to control prawns. For the antioxidant status analysis, glutathione peroxidase, glutathione reductase, and glutathione s-transferase of prawn fed the SSe-enriched diet at 1 mg (kg diet)(-1) were significantly increased. The results indicated that the cheaper selenium, SSe is recommended to be added in prawn feed at the concentration of 0.5 mg resulting in 1.5 mg SSe (kg diet)(-1) increased prawn immunity and disease resistance against the pathogen, D. hansenii. PMID:20561587

  16. Effect of hypoxia on the immune response of giant freshwater prawn Macrobrachium rosenbergii and its susceptibility to pathogen Enterococcus

    Microsoft Academic Search

    Winton Cheng; Chun-Hung Liu; Jung-Ping Hsu; Jiann-Chu Chen

    2002-01-01

    Giant freshwater prawns Macrobrachium rosenbergii (14–19g) were challenged withEnterococcus (3×105cfu prawn?1) previously incubated in TSB medium for 24h, then placed in water having concentrations of dissolved oxygen (DO) at 7·75, 4·75, 2·75 and 1·75mg l?1. Onset of mortality occurred after 6h exposure to 1·75mg l?1 DO, and after 12h exposure to 2·75mg l?1 DO. Cumulative mortality of prawns at 1·75mg

  17. Fires in the Amazon

    NSDL National Science Digital Library

    Payne, Laura X.

    1998-01-01

    This week's In The News covers the issues around the massive fires burning in the Brazilian Amazon. The nine sites listed provide information and commentary on the global issue. Since July 1997, the media has paid attention to the Brazilian Amazon, as fires there increased and raged out of control. Thought to have been started by slash-and-burn agriculturists, these fires were influenced by El Nino weather patterns and spread in size and intensity until reaching devastating heights in late March, 1998. Although a fortuitous three-day rain extinguished most fires, experts warn that the threat of future fires remains high. While Brazil has received much attention in recent months, such fires are not limited to South America; Indonesia and other tropical countries face similar disturbances to their ecological and economic environments.

  18. Mosquito larvicidal potential of some extracts obtained from the marine organisms? prawn and sea cucumber

    Microsoft Academic Search

    Narsinh L Thakur; Sandhya P Mainkar; Reena A Pandit; Madhavi M Indap

    The larvicidal potential of two marine organisms was investigated by testing their non-polar to polar organic extracts against mosquito Culex pipens fatigans. In the present investigation the non-polar petroleum ether extract of prawn Nematopalaemon. tenuipes, Hendersen and polar methanol extract of sea cucumber Holothuria scabra, Jaeger body wall were found to be effective against mosquito larvae. The preliminary chemical analysis

  19. Study of biochemical biomarkers in freshwater prawn Macrobrachium borellii (Crustacea: Palaemonidae) exposed to organophosphate fenitrothion.

    PubMed

    Lavarías, S; García, C; Crespo, R; Pedrini, N; Heras, H

    2013-10-01

    Several agrochemicals like organophosphates are extensively used to control pests in agricultural practices but they also adversely affect non-target fauna. The effect of organophosphorous fenitrothion on the prawn Macrobrachium borellii was evaluated. The 96-h LC50 was determined. Activity of superoxide dismutase, catalase, glutathione-S-transferase and lipid oxidation levels, were evaluated in the hepatopancreas from adults exposed to sublethal fenitrothion concentrations for 1, 2, 4 and 7 days. In addition, superoxide dismutase mRNA expression, acetylcholinesterase inhibition and haemocyte DNA damage were determined. The 96-h LC50 was 4.24?g/l of fenitrothion. Prawn exposed to sublethal FS concentrations showed an increase of both catalase and superoxide dismutase activities, mainly after 2 and 4 days exposure and an increase of glutathione-S-transferase activity from day 2 to day 7 while lipid oxidation levels increased mainly on day 1. Superoxide dismutase transcripts were significantly higher in fenitrothion -treated prawns, indicating an induction mechanism. Hemolymph analysis showed that while acetylcholinesterase activity decreased after 2 days, haemocytes displayed most DNA damage after 7-day exposure to fenitrothion. These results indicate that prawn enzymes are highly sensitive to fenitrothion exposure, and these biological responses in M. borellii could be valuable biomarkers to monitor organophosphorous contamination in estuarine environments. PMID:23876938

  20. A Simple "in Vitro" Culture of Freshwater Prawn Embryos for Laboratory Investigations

    ERIC Educational Resources Information Center

    Porntrai, Supaporn; Damrongphol, Praneet

    2008-01-01

    Giant freshwater prawn ("Macrobrachium rosenbergii" De Man) embryos can be cultured "in vitro" to hatching in 15% (v/v) artificial seawater (ASW). This technique can be applied as a bioassay for testing toxicity or for the effects of various substances on embryo development and can be used as a simple and low-cost model for studying embryo…

  1. AbstractThe bycatch of Australia's northern prawn fishery (NPF) com

    E-print Network

    800 Abstract­The bycatch of Australia's northern prawn fishery (NPF) com prises 56 elasmobranch addressed. We obtained esti mates of catch rates and the within-net survival of elasmobranchs. Carcha rhinus the sustainability of elasmobranchs that are caught as bycatch by highlighting species for management and research

  2. Monodon baculovirus (MBV) infects the freshwater prawn Macrobrachium rosenbergii cultivated in Thailand

    Microsoft Academic Search

    Warachin Gangnonngiw; Kesinee Laisutisan; Siriporn Sriurairatana; Saengchan Senapin; Niti Chuchird; Chalor Limsuwan; Parin Chaivisuthangkura; Timothy W. Flegel

    2010-01-01

    Field specimens of post-larvae of the giant freshwater prawn (Macrobrachium rosenbergii) from Thailand showed hepatopancreatic tubule epithelial cells that contained central, eosinophilic inclusions within enlarged nuclei and marginated chromatin. These inclusions resembled those produced by some baculoviruses prior to formation of occlusion bodies that enclose virions in a polyhedrin protein matrix. By electron microscopy, the intranuclear inclusions contained bacilliform, enveloped

  3. Molecular Characterisation of Colour Formation in the Prawn Fenneropenaeus merguiensis

    PubMed Central

    Ertl, Nicole G.; Elizur, Abigail; Brooks, Peter; Kuballa, Anna V.; Anderson, Trevor A.; Knibb, Wayne R.

    2013-01-01

    Introduction Body colouration in animals can have a range of functions, with predator protection an important aspect of colour in crustaceans. Colour determination is associated with the carotenoid astaxanthin, which is taken up through the diet and stabilised in the tissues by the protein crustacyanin. As a variety of genes are found to play a role in colour formation in other systems, a holistic approach was employed in this study to determine the factors involved in Fenneropenaeus merguiensis colouration. Results Full length F. merguiensis crustacyanin subunit A and C sequences were isolated. Crustacyanin subunit A and C were found in the F. merguiensis transcriptomes of the muscle/cuticle tissue, hepatopancreas, eye stalk and nervous system, using 454 next generation sequencing technology. Custom microarray analysis of albino, light and dark F. merguiensis cuticle tissue showed genes encoding actin, sarcoplasmic calcium-binding protein and arginine kinase to be 4-fold or greater differentially expressed (p<0.05) and down-regulated in albinos when compared to light and dark samples. QPCR expression analysis of crustacyanin and total astaxanthin pigment extraction revealed significantly (p<0.05) lower crustacyanin subunit A and C gene transcript copy numbers and total astaxanthin levels in albinos than in the light and dark samples. Additionally, crustacyanin subunit A and C expression levels correlated positively with each other. Conclusions This study identified gene products putatively involved in crustacean colouration, such as crustacyanin, sarcoplasmic calcium-binding protein and forms of actin, and investigated differences in gene expression and astaxanthin levels between albino, light and dark coloured prawns. These genes open a path to enhance our understanding of the biology and regulation of colour formation. PMID:23441225

  4. Molecular and immunological responses of the giant freshwater prawn, Macrobrachium rosenbergii, to the organophosphorus insecticide, trichlorfon.

    PubMed

    Chang, Chin-Chyuan; Rahmawaty, Atiek; Chang, Zhong-Wen

    2013-04-15

    Trichlorfon is an organophosphorus (OP) insecticide that is used as an agriculture pesticide to destroy insects, a human medicine to combat internal parasites, and an ectoparasiticide in the livestock and aquaculture industries, but which has caused aquatic toxicity in the prawn industry. The aim of this study was to investigate the effects of trichlorfon on molecular and enzymatic processes of the immunological response of the giant freshwater prawn, Macrobrachium rosenbergii, at 0, 0.2, and 0.4mgL(-1) with 0, 3, 6, 12, and 24h of exposure. The total hemocyte count (THC), respiratory bursts (RBs), phenoloxidase (PO) activity, and superoxide dismutase (SOD) activity were examined to evaluate immunological responses and oxidative stress. Results showed that THCs of the prawn exposed to trichlorfon at both concentrations (0.2 and 0.4mgL(-1)) had increased after 12 and 24h; SOD and PO activities had significantly increased at 3h, whereas production of RBs had dramatically increased as oxidative stress at each sampling time after exposure to trichlorfon compared to the control. A potential biomarker of OPs, acetylcholinesterase (AChE) revealed a significant decrease after exposure for 6h, and showed a time-dependent tendency. Immune gene expressions, including prophenoloxidase (proPO), the lipopolysaccharide- and ?-1,3-glucan-binding protein (LGBP), peroxinectin (PE), ?2-macroglubulin (?2M), transglutaminase (TG), and copper, zinc (Cu,Zn)-SOD, of prawns exposed to trichlorfon at 0, 0.2, and 0.4mgL(-1) for 0, 6, and 24h were further evaluated. Expressions of all of the immune genes significantly decreased when prawns were exposed to 0.4mgL(-1) trichlorfon for 24h, and among them, an increase in SOD expression was seen after exposure to 0.4mgL(-1) for 6h. Prawns exposed to trichlorfon within 24h exhibited the decrease of circulating hemocytes, and also the induction of oxidative stress, which caused subsequent damage to DNA formation of immune genes. From these results, we concluded that immunological responses and immune gene expressions of prawn exposed to trichlorfon at 0.4mgL(-1) for 24h were perturbed, thus causing a deficiency in immunity and subsequent increased susceptibility to pathogen infections. PMID:23340335

  5. Mapping the Amazon: The Mouth of the Amazon

    NSDL National Science Digital Library

    Stuart Snodgrass

    2002-03-14

    The Amazon rain forest is the largest tropical forest in the world. It stretches across South America from nearly ocean to ocean. No seasonal view of this territory existed until a NASA-university collaboration began mapping the Amazon - from space. Scientists listed worked as a team on Mosaicking Software and Mosaic Production.

  6. Influence Deforestation on Hydrological Cycle at Amazon Basin

    NASA Astrophysics Data System (ADS)

    Cohen, J. C.; Beltrao, J.; Gandu, A. W.

    2007-05-01

    The last three decades, the Amazon Basin has been affected for the occupation with consequence large deforestation. The principal area deforested is located from Maranhao state to Rondonia state. This area is common called "Arc Deforestation", and representing the transition between two important Brazilian ecosystems, Amazon Forest and Savanna Region. Theses ecosystems have precious biodiversity, and it has population about 10.331.000. The objective of this work was to evaluate the impact of arc deforestation on the hydrological cycle at Amazon basin, using BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) including a model of dynamic vegetation, called GEMTM (General Energy and Mass Transport Model). In this study, numerical simulations were performed with a high spatial resolution regional model that allows capture some mesoscale aspects associated to the land used, topography, coastlines and large rivers. In order to predict the impact of the arc deforestation over the hydrological cycle, it was run two model simulations, conducted over a one-year period. In the first simulation, designated "control", it was used the scenarios derived from Soares Filho (2002), for the year 2002, in governance situation. In the second simulation called "deforestation", it was used the scenarios for the 2050, derived from results of Soares-Filho with governance, too. The higher-resolution regional modeling revealed important features of the deforestation process, displaying some associated mesoscale effects that are not typically represented in similar Global Circulation Model simulations. Near coastal zones and along large rivers, deforestation resulted in reduced precipitation. However, it was predicted increased precipitation over mountainous areas, especially on mountain slopes facing river valleys. Then, these higher-resolution simulations showed that, in general, orography, coastline profile and large river distribution play important roles in determining anomaly patterns of precipitation in Amazon Basin. It had seen an increase in the rain in the deforested regions, and it did not have substantial effect in the undisturbed regions. It was still observed, increase of temperature in the deforested region.

  7. Impact of methylparathion and malathion on cholinergic and non-cholinergic enzyme systems of penaeid prawn, Metapenaeus monoceros.

    PubMed

    Reddy, M S; Jayaprada, P; Rao, K V

    1990-11-01

    The nervous tissue AChE, BUChE and glutaminase activity levels were significantly inhibited, whereas glutamine synthetase activity, acetylcholine and glutamine contents were increased significantly following the sublethal exposure of prawn, Metapenaeus, monoceros to methylparathion and malathion. During OPI exposure ammoniagenesis was triggered by increased deamination of purines and oxidative deamination of glutamate. This results in the hyperammonemia. As a consequence of hyperammonemia, the OPI exposed prawn tissue have adopted the suitable mechanisms to detoxity the ammonia by enhancing the synthesis of urea and glutamine. From the study, it has been observed that 10 days of reclamation period is not enough but the prawn nervous tissue showed efficient mechanisms for the detoxification or biodegradation of OPI molecules, which will pave way for the successful survival prawns. PMID:1981826

  8. The toxic effect of phthalate esters on immune responses of giant freshwater prawn ( Macrobrachium rosenbergii) via oral treatment

    Microsoft Academic Search

    Wen-Liang Chen; Hung-Hung Sung

    2005-01-01

    A previous in vitro study has indicated that four phthalate esters (PAEs) could damage hemocytes and decreases the cellular immunity of prawns [Sung, H.H., Kao, W.Y., Su, Y.J., 2003. Effects and toxicity of phthalate esters to hemocytes of giant freshwater prawn, Macrobranchium rosenbergii. Aquat. Toxicol. 64, 25–37]. The aim of this study was to investigate the in vivo effect of

  9. The fish and prawn communities of a Malaysian coastal mangrove system, with comparisons to adjacent mud flats and inshore waters

    NASA Astrophysics Data System (ADS)

    Chong, V. C.; Sasekumar, A.; Leh, M. U. C.; D'Cruz, R.

    1990-11-01

    The fish and prawn communities of four coastal habitats in Selangor, Malaysia: (1) coastal mangrove swamps; (2) mud flats, including subtidal regions; (3) near inshore waters; and (4) far inshore waters, were examined with respect to species composition, abundance, diversity, similarity and sexual maturity. The number of fish species sampled for these habitats were 119, 70, 58 and 92 species respectively. For prawns, the number of species were 9, 16, 8 and 14 respectively. The mangrove community comprised 63-99% and 100% juvenile fish and prawn respectively. Despite a high species richness, it was low in fish species diversity due to the dominance (70%) of six species of fish of low economic value. In contrast, the prawn community was poor in species, and was dominated by three Penaeus spp. of high economic value. The intertidal mudflat community is largely transient and comprised mainly of species from both the mangrove and subtidal habitats. Fifty-six per cent of the fish population and 62·6% of the prawn population were juveniles. Many of the inshore fish and prawn species were also common species found in mangrove and mudflat habitats. Similarity coefficients indicate that the inshore fish and prawn communities are more similar to those of mud flats than mangroves. However, maturity studies indicate that only five species of fish are true migrants, that the majority of the fish species (juveniles and adults) are ubiquitous with a distribution that extends several nautical miles offshore. Results of this study indicate that tropical coastal mangroves function more importantly as feeding grounds than as nursery grounds for juveniles of commercially important fish species. Mangroves and mud flats are utilized during flood tides by many periodic foragers from the inshore waters. However, this study confirms that coastal mangroves and mud flats are important nursery areas for commercially important prawn species.

  10. Effect of benzalkonium chloride stress on immune resistance and susceptibility to Lactococcus garvieae in the giant freshwater prawn Macrobrachium rosenbergii.

    PubMed

    Cheng, Winton; Wang, Ching-Hsien; Chen, Jiann-Chu

    2003-02-27

    Addition of benzalkonium chloride (BKC) at 0, 0.3, 0.6 and 1.0 mg l(-1) to tryptic soy broth (TSB) had no effect on growth of Lactococcus garvieae, a bacterial pathogen of the giant freshwater prawn Macrobrachium rosenbergii. However, injection of the cultured cells into prawns at a dose of 4 x 10(6) colony-forming units (cfu) prawn(-1) resulted in significantly higher mortality at 120 h (p < 0.05) in prawns injected with cells grown in the absence of BKC than in prawns injected with cells grown in the presence of BKC. In other experiments, prawns were injected with TSB-grown L. garvieae (4 x 10(6) and 3 x 10(5) cfu prawn(-1)) and then held in water containing BKC at 0, 0.3, 0.6 and 1.0 mg l(-1). After 120 h, mortality was significantly higher in all the BKC treatments than in the control without BKC. Prawns showed no significant differences in total hemocyte count (THC) or differential hemocyte count (DHC) amongst treatment and control groups. However, 96 h exposure to 0.3 mg l(-1) BKC or more resulted in a decrease in phenoloxidase activity and an increase in respiratory burst to levels considered to be cytoxic. In summary, exposure of L. garvieae to BKC at 0.3 mg l(-1) or more decreased its virulence to M. rosenbergii, while exposure of M. rosenbergii to BKC at 0.3 mg l(-1) or more increased its susceptibility to L. garvieae infection. PMID:12691193

  11. Production and economic efficiencies of intensive black tiger prawn ( Penaeus monodon ) culture during different cropping seasons in the Mekong delta, Vietnam

    Microsoft Academic Search

    Vu Nam Son; Nguyen Thanh Phuong; Tran Ngoc Hai; Amararatne Yakupitiyage

    2011-01-01

    Production management of intensive prawn farming strongly differs between dry and wet season in terms of availability and\\u000a quality of prawn seeds and water quality. Secondary data implied that prawn seed batches from the market had a total pathogen\\u000a infection rate of 53%, predominantly caused by 37% white spot syndrome virus (WSSV), 19% monodon baculovirus (MBV) and 4%\\u000a yellow head

  12. Isolation and characterization of a female-specific DNA marker in the giant freshwater prawn Macrobrachium rosenbergii

    PubMed Central

    Ventura, T; Aflalo, E D; Weil, S; Kashkush, K; Sagi, A

    2011-01-01

    In this study, a female-specific DNA marker in the freshwater prawn Macrobrachium rosenbergii was identified through amplified fragment length polymorphism (AFLP). The AFLP-derived sequence-characterized amplified region (SCAR) marker was tested in over 200 individuals, giving reproducible sex identification. Further molecular characterization of the sex-marker's genomic region (?3?kb long) revealed the presence of tandem and inverted repeats. The ?3-kb sequence was identified both in male and female prawns, but with subtle differences: a deletion of 3?bp (present in female prawn but absent in male prawn) identified upstream of the SCAR marker sequence and two female-specific single-nucleotide polymorphisms, both indicating that male prawns are homozygous, whereas female prawns are heterozygous in this locus. Fluorescent in situ hybridization showed the ?3-kb sequence to be unique: to the best of our knowledge, this is the first report of a unique sex-specific sequence observed in situ in crustaceans. The sex-specific marker identified in M. rosenbergii may have considerable applied merit for crustacean culture in that it will enable the determination of genetic sex at early developmental stages when phenotypic differences are not identifiable. PMID:21522169

  13. Current Characterization at the Amazon estuary

    NASA Astrophysics Data System (ADS)

    Bezerra, M. O.

    2009-04-01

    At the estuary there are several mechanisms that cause turbulence: influence of solid contours (estuary bottom and shores), speed vertical shearing (fluid inside), wind shearing stress (free surface) and surface and internal gravity waves. Turbulence intensity controls vertical distribution of estuary water mass property concentration. As flow into the estuary takes place during the transition or turbulent regimen, produced by small space and time scale movements, entrainment, turbulent scattering and advection are the processes responsible for fresh water mixing up with the sea and for local salinity variation, as well as for concentration of natural properties and man-made ones. According to this focus, we shall describe general circulation, conveyance and mixing characteristics of the Amazon low estuary waters. Amazon estuary shows unusual characteristics: it is of vast length and enormous outflow. It is extremely wide - 150 Km - and its discharge into the Atlantic amounts to 180,000 m3s-1 (Otman, 1968, Figueiredo et al, 1991), which means 18% of all water discharged by rivers into oceans; this is the largest punctual source of fresh water for oceans (Milliman and Meade, 1983). Maximum outflow is 2.5 x 105 m3s-1, and it happens at the end of May. Minimum outflow is 1.2 x 105 m3 s-1, and it takes place in November. At Amazon River, the Mixing Zone occurs where the Coastal Zone usually is. The reason for that is the extension of fresh water plume moves Northeast for over 1000 Km (Gibbs, 1970; Muller-Karger et al 1988). This is the most extensive estuarine plume ever found in the ocean. During low fluvial discharge (June-November) plume reaches 300 Km; however, on high discharge (November-May) plume reaches 500 Km. Plume already is 3 to 10 m thick and 80 to 300 Km wide (Lentz and Limeburner, 1995). From June to January plume moves towards Africa, from whence 70% of it goes east carried by North Brazil Current retroflection and 30% goes towards the Caribbean. From February to May, the plume goes northwest towards the Caribbean. As to classification according to salinity stratification, at the quadrature the Amazon estuary is considered as "Saline Wedge" type (highly stratified estuary), salinity at 120 Km way from river moth standing out, whereas at sysygy it can be classified as well mixed (Limeburner et al. 1991e 1992; Patchineelam, 2004). Fresh water is everywhere in the river area, salty or mixed water is located in the ocean. In this estuary 90 Km away from the mouth surface water salinity is less than 0.05 and bottom salinity at 14 m deep is about 19 at high water on quadrature at the end of the rainy season. This behavior produces marked difference in the vertical salinity profile, showing the current is moving in the opposite direction (river fresh water and salty water brought by the tide). In this scenario, speed shearing at the interface produces interfacial friction stress that, from the entrainment process carries portions of water from the sea to the upper part. Usually, therefore, in "saline wedge" (highly stratified estuary) type estuaries, when river discharge is more intensive than the tide wave, entrainment is the predominant mechanism; and the greater tide amplitude is, the greater will its influence be to produce turbulent scattering and mixing be. Probably, at Amazon estuary quadrature entrainment processes are predominant and are the ones responsible for increased salinity in surface layer, whereas turbulence scattering mixing is secondary to it. "Saline wedge" (highly stratified estuary) type estuaries are typical of large fluvial discharge and microtide regions. But although the Amazon estuary is a macrotide region, this stratification is due to the river's exceptional discharge. Due to the remarkable river plume discharge on the platform, the tide - a dominant in macrotide region estuarine circulation - now has a secondary role, albeit not a negligible one, with quadrature amplitudes varying from 2 m to 90 Km from the mouth. It is important to point out that tide-ind

  14. Copepods and fishes in the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Thatcher, Vernon E.

    1998-06-01

    The Amazon basin comprises the largest river ecosystem in the world (7 million km 2) with annual high and low water peaks and a constant temperature near 29°C. Some 2000 fish species and 40 species of free-living copepods are known to occur in Amazonia. The free-living forms serve as food for most larval fishes and some adults, but they also transmit several parasites including representatives of the nematode family Camallanidae. About three dozen species of parasitic copepods have been described from the Brazilian Amazon. Females of Amazonian parasitic copepods are found on skin, gill filaments, gill rakers or within the nasal fossae. Parasitic copepods are found on fishes that are from a few millimeters long up to those over 2 m in length and they are usually quite host specific. All have body pigmentation in different patterns and colors (frequently blues, such as cerulean, cobalt, spectrum, smalt or campanula). It is suggested that the coloration serves to attract specific host fish. Copepods have evolved adaptations for attachment and feeding, especially in the second antennae and endopods. Examples of progenesis, phoresis and commensalism are shown. Some species produce pathology such as a tourniquet effect, hyperplasia, blood loss and anemia, and can kill fishes by limiting their respiration.

  15. Reexamining the late Cenozoic geologic evolution of the Amazon basin

    NASA Astrophysics Data System (ADS)

    Rigsby, C. A.; Latrubesse, E. M.; Baker, P. A.; Silva, C. G.

    2010-12-01

    The recent geologic evolution of the Amazon basin has been the focus of many recent studies. Our own research and our review of the literature suggest a need for reevaluation of many aspects of this history including several key questions: What was the timing of Andean uplift (especially, the Western Cordillera)? What is the relationship between the northernmost Solimões Formation and northern Andean tectonic activity? What is the precise age of the lowermost levels of the Solimões Formation? Were there marine incursions? Are tidal deposits recorded in Amazonia? Was there a very large, long-lived, Miocene "Pebas" megalake in the western Amazon? When did the trans-continental, eastern outlet, Amazon drainage become established? What is the antiquity of the Amazon fan? Correct answers to these questions are essential in order to gain a better understanding of the climatic and biogeographic history of the Amazon basin. Although several authors have suggested the existence of late Miocene tidal sediments deposited during a sea-level high stand and marine transgressions into the Amazon basin from the north (Caribbean Sea) or from the south (Paranáense Sea), both the existence of a late Miocene seaway through western Amazonia and the existence of thousands of square kilometers affected by tides are difficult to support. The faunal composition and pollen content of the upper Miocene Solimões Formation are inconsistent with tidal/marine environments. And, as we have demonstrated, deposits in Peruvian Amazonia that have been attributed to Miocene tidal environments are actually fluvial sediments that have been environmentally and chronologically misinterpreted. Further, the existence of a giant paleolake in western Amazonia during the middle to late Miocene is inconsistent with our paleoenvironmental reconstructions of shifting rivers in aggradational conditions - reconstructions that are consistent with the interpretations of the Solimões Formation in other parts of the basin and with sedimentary architecture at both basin scale and depositional-system scale. We have previously suggested that ca. 5 Ma, during the period when low-angle subduction was fully developed in the Nazca Plate between ~3° and 15°S, reorganization of drainage resulted in the transformation of the southwestern Brazilian Amazon from a basin that trapped sediments to an erosional region that contributed sediments to the Amazon fluvial system. It is likely that at that time the lowland fluvial systems of southwestern Amazonia began to drain to the Atlantic Ocean. A ca. 5 Ma reorganization of the Amazon fluvial system and its connection with the Atlantic Ocean is consistent with the record of terrigenous deposits in the Ceara Rise, close to the Amazon cone. Our analysis of new cores and seismic data from the Amazon fan, as well as a combined morphostratigraphic and biostratigraphic analysis of the western Amazonian lowlands, will provide additional clues to the relationship between tectonics, sea level, and the evolution of the trans-continental Amazon drainage.

  16. Antioxidant enzymes in freshwater prawn Macrobrachium malcolmsonii during embryonic and larval development

    Microsoft Academic Search

    S. Arun; P. Subramanian

    1998-01-01

    Activities of superoxide dismutase, catalase, glutathione peroxidase (selenium-dependent and selenium-independent) and glutathione-S-transferases were analysed in freshwater prawn Macrobrachium malcolmsonii during embryonic and larval development. An elevated level of these enzymes was encountered in the larval stage of M. malcolmsonii when compared to its preceding embryonic stages. Enzyme activities were also analysed in hepatopancreas, muscle and gill of M. malcolmsonii sub-adults

  17. Responses of Giant Freshwater Prawn ( Macrobrachium rosenbergii) to Challenge by Two Strains of Aeromonas spp

    Microsoft Academic Search

    Hung-Hung Sung; Shu-Fen Hwang; Fu-Ming Tasi

    2000-01-01

    The virulence of two Aeromonas strains (A. veronii and A. caviae) isolated from the hepatopancreas of apparently healthy giant freshwater prawns (Macrobrachium rosenbergii) was compared using a challenge by injections. For the A. veronii strain, challenge with 3.7 × 105 cells\\/g of body weight led to 100% mortality; for the A. caviae strain, 3.8 × 106 cells\\/g produced 100% mortality.

  18. Ingestion and absorption of nutrients by the freshwater prawn (Macrobrachium rosengergii)

    E-print Network

    Taechanuruk, Suchat

    1982-01-01

    will fulfill the requirements of the animal. Therefore, in order to minimize wastage of food and thus reduce the cost of feeding, each feed ingredient must be evaluated in terms of the ability of the animal to digest and absorb it. Knowledge of availability... and can decay, adversely affecting water quality. Bacterial growth on unconsumed food can further stress the culture system (Shlesser and Gallagher, 1974). In order to obtain maximum growth of prawns, feed should not only be of high nutritional quality...

  19. Involvement of opioid peptides in the regulation of reproduction in the prawn Penaeus indicus

    NASA Astrophysics Data System (ADS)

    Sreenivasula Reddy, P.

    The possible involvement of an endogenous opioid system in the regulation of ovarian development in the prawn Penaeus indicus was investigated. Injection of leucine-enkephalin significantly increased the ovarian index and oocyte diameter in a dose-dependent manner. In contrast, injection of methionine-enkephalin significantly decreased the ovarian index and oocyte diameters. These results provide evidence to support the hypothesis that an opioid system is involved in the regulation of reproduction in crustaceans.

  20. Trophic Value of the Unicellular Diatom Phaeodactylum tricornutum for Larvae of Kuruma Prawn, Penaeus japonicus

    Microsoft Academic Search

    Masanori Okauchi; Masaharu Tokuda

    The trophic value of the unicellular and silica-less diatom, Phaeodactylum tricornutum for the larvae of kuruma prawn, Penaeus japonicus, was evaluated in uni-algal culture, nutritive analyses and larval rearing in this experiment. The algal strain of Ph. tricornutum used in this experiment had been selected by more than 100 repeat colony screenings using an agar medium under 30°and light conditions

  1. In vitro inhibition of Ca+2 ATPase by methylparathion in prawn: a kinetic approach.

    PubMed

    Reddy, M S; Rao, K V

    1990-12-01

    After in vitro addition of IC50 concentration of methylparathion on Ca+2 ATPase in nervous and hepato-pancreatic tissues of prawn were studied. The inhibitory pattern of Ca+2 ATPase elucidate the interaction of methylparathion with ATPase system. The significant decrease in maximal velocity (Vmax) without appreciable change in apparent Michaelis-Menten constant (Km) suggests that the impact of methylparathion on Ca+2 ATPase is independent of substrate and is of a classical non-competitive type. PMID:2151019

  2. Identification of the major allergen of Macrobrachium rosenbergii (giant freshwater prawn)

    PubMed Central

    Yadzir, Zailatul Hani Mohamad; Misnan, Rosmilah; Abdullah, Noormalin; Bakhtiar, Faizal; Arip, Masita; Murad, Shahnaz

    2012-01-01

    Objective To characterize the major allergens of Macrobrachium rosenbergii (giant freshwater prawn). Methods Raw and cooked extracts of the giant freshwater prawn were prepared. The IgE reactivity pattern was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting technique with the sera of 20 skin prick test (SPT) positive patients. The major allergen identified was then characterized using the proteomics approach involving a combination of two-dimensional (2-DE) electrophoresis, mass spectrometry and bioinformatics tools. Results SDS-PAGE of the raw extract showed 23 protein bands (15–250 kDa) but those ranging from 40 to 100 kDa were not found in the cooked extract. From immunoblotting experiments, raw and cooked extracts demonstrated 11 and 5 IgE-binding proteins, respectively, with a molecular mass ranging from 15 to 155 kDa. A heat-resistant 36 kDa protein was identified as the major allergen of both extracts. In addition, a 42 kDa heat-sensitive protein was shown to be a major allergen of the raw extract. The 2-DE gel fractionated the prawn proteins to more than 50 different protein spots. Of these, 10 spots showed specific IgE reactivity with patients' sera. Matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis led to identification of 2 important allergens, tropomyosin and arginine kinase. Conclusions It can be concluded that the availability of such allergens would help in component-based diagnosis and therapy of prawn allergies. PMID:23569834

  3. Isolation and molecular identification of planctomycete bacteria from postlarvae of the giant tiger prawn, Penaeus monodon.

    PubMed Central

    Fuerst, J A; Gwilliam, H G; Lindsay, M; Lichanska, A; Belcher, C; Vickers, J E; Hugenholtz, P

    1997-01-01

    Bacteria phenotypically resembling members of the phylogenetically distinct planctomycete group of the domain Bacteria were isolated from postlarvae of the giant tiger prawn, Penaeus monodon. A selective medium designed in the light of planctomycete antibiotic resistance characteristics was used for this isolation. Planctomycetes were isolated from both healthy and monodon baculovirus-infected prawn postlarvae. The predominant colony type recovered from postlarvae regardless of viral infection status was nonpigmented. Other, less commonly observed types were pink or orange pigmented. A planctomycete-specific 16S rRNA-directed probe was designed and used to screen the isolates for their identity as planctomycetes prior to molecular phylogenetic characterization. 16S rRNA genes from nine prawn isolates together with two planctomycete reference strains (Planctomyces brasiliensis and Gemmata obscuriglobus) were sequenced and compared with reference sequences from the planctomycetes and other members of the domain Bacteria. Phylogenetic analyses and sequence signatures of the 16S rRNA genes demonstrated that the prawn isolates were members of the planctomycete group. Five representatives of the predominant nonpigmented colony type were members of the Pirellula group within the planctomycetes, as were three pink-pigmented colony type representatives. Homology values and tree topology indicated that representatives of the nonpigmented and pink-pigmented colony types formed two discrete clusters within the Pirellula group, not identical to any known Pirellula species. A sole representative of the orange colony type was a member of the Planctomyces group, virtually identical in 16S rDNA sequence to P. brasiliensis, and exhibited distinctive morphology. PMID:8979353

  4. Mass-physical and geotechnical properties of surficial sediments and dense nearbed sediment suspensions on the Amazon continental shelf

    Microsoft Academic Search

    Richard W. Faas

    1986-01-01

    Mass-physical and geotechnical properties of the surficial (to 3 m) sediments on the Amazon continental shelf were analyzed from 36 short (0.5 m) and longer (3m) cores obtained during a June July 1983 cruise which coincided with the high discharge period of the Amazon River. Data included undrained shear strength (measured by a hand-held shear vane) and water content measurements,

  5. Low-water maps of the groundwater table in the central Amazon by satellite altimetry

    NASA Astrophysics Data System (ADS)

    Pfeffer, Julia; Seyler, Frédérique; Bonnet, Marie-Paule; Calmant, Stéphane; Frappart, Frédéric; Papa, Fabrice; Paiva, Rodrigo C. D.; Satgé, Frédéric; Silva, Joecila Santos Da

    2014-03-01

    Groundwater plays a fundamental role in rainforest environments, as it is connected with rivers, lakes, and wetlands, and helps to support wildlife habitat during dry periods. Groundwater reservoirs are however excessively difficult to monitor, especially in large and remote areas. Using concepts from groundwater-surface water interactions and ENVISAT altimetry data, we evaluated the topography of the groundwater table during low-water periods in the alluvial plain of the central Amazon. The water levels are monitored using an unprecedented coverage of 491 altimetric stations over surface waters in the central Amazon. The groundwater table maps interpolated at spatial resolutions ranging from 50 to 100 km are consistent with groundwater wells data. They provide evidence of significant spatiotemporal organization at regional scale: heterogeneous flow from the hillslope toward the main rivers is observed, as well as strong memory effects and contrasted hydrological behaviors between the North and the South of the Amazon.

  6. Deforestation, floodplain dynamics, and carbon biogeochemistry in the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Bryan, M. L.; Dunne, T.; Richey, J.; Melack, J.; Simonett, D. S.; Woodwell, G.

    1984-01-01

    Three aspects of the physical geographic environment of the Amazon Basin are considered: (1) deforestation and reforestation, (2) floodplain dynamics, and (3) fluvial geomorphology. Three independent projects are coupled in this experiment to improve the in-place research and to ensure that the Shuttle Imaging Radar-B (SIR-B) experiment stands on a secure base of ongoing work. Major benefits to be obtained center on: (1) areal and locational information, (2) data from various depression angles, and (3) digital radar signatures. Analysis will be conducted for selected sites to define how well SIR-B data can be used for: (1) definition of extent and location of deforestation in a tropical moist forest, (2) definition and quantification of the nature of the vegetation and edaphic conditions on the (floodplain) of the Amazon River, and (3) quantification of the accuracy with which the geometry and channel shifting of the Amazon River may be mapped using SIR-B imagery in conjunction with other remote sensing data.

  7. Ballast water: a threat to the Amazon Basin.

    PubMed

    Pereira, Newton Narciso; Botter, Rui Carlos; Folena, Rafael Dompieri; Pereira, José Pinheiro Fragoso Neto; da Cunha, Alan Cavalcanti

    2014-07-15

    Ballast water exchange (BWE) is the most efficient measure to control the invasion of exotic species from ships. This procedure is being used for merchant ships in national and international voyages. The ballast water (BW) salinity is the main parameter to evaluate the efficacy of the mid-ocean ballast water exchange. The vessels must report to the Port State Control (PSC), via ballast water report (BWR), where and how the mid-ocean BWE was performed. This measure allows the PSC to analyze this information before the ship arrives at the port, and to decide whether or not it should berth. Ship BW reporting forms were collected from the Captaincy of Santana and some ships were visited near the Port of Santana, located in Macapá (Amazon River), to evaluate the BW quality onboard. We evaluated data submitted in these BWR forms and concluded that the BWE efficacy might be compromised, because data contained in these BWR indicate that some ships did not change their BW. We found mistakes in filling the BWR forms and lack of information. Moreover, these ships had discharged BW with high level of salinity, Escherichia coli and total coliforms into the Amazon River. We concluded that the authorities of the Amazon Region need to develop more efficient proceedings to evaluate the ballast water reporting forms and BW quality, as there is potential risk of future invasion of exotic species in Brazilian ports. PMID:24928458

  8. Identification and function of 11 Rab GTPases in giant freshwater prawn Macrobrachium rosenbergii.

    PubMed

    Huang, Ying; Ren, Qian

    2015-03-01

    Rab GTPases, members of the Ras-like GTPase superfamily, are central elements in endocytic membrane trafficking. However, little is known of the Rab genes in the giant freshwater prawn Macrobrachium rosenbergii. In this study, 11 Rab genes were identified from M. rosenbergii. All MrRabs have a RAB domain. Phylogenetic analysis showed that these 11 MrRabs were divided into different groups. The MrRab genes were ubiquitously expressed in heart, hemocytes, hepatopancreas, gills, stomach, and intestines. Real-time polymerase chain reaction revealed that the MrRab genes were significantly upregulated by white spot syndrome virus (WSSV) in the prawns, indicating that MrRabs might play an important role in innate immune response against WSSV. Moreover, after challenge with Vibrio parahaemolyticus, the expression levels of all MrRabs in the hepatopancreas were also upregulated, which might indicated the involvement of MrRabs in prawns antibacterial immunity. In all, these preliminary results showed that MrRabs were involved in innate immunity of M. rosenbergii. PMID:25542378

  9. Acute toxicity of organophosphate fenitrothion on biomarkers in prawn Palaemonetes argentinus (Crustacea: Palaemonidae).

    PubMed

    Lavarías, S; García, C F

    2015-03-01

    The effect of the organophosphate fenitrothion (FS) on the non-target freshwater prawn Palaemonetes argentinus was studied. Initially, the 96-h lethal concentration (LC50) of FS was determined in adult prawns. Inhibition of cholinesterase (ChE) in the muscle and hemolymph was assessed. Then, in the hepatopancreas, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) were analyzed. Lipid peroxidation (LPO) was also determined in the hepatopancreas. The 96-h LC50 value was 1.12 ?g/L. Hemolymph ChE activity showed a significant decrease in exposed prawns to FS compared to the control group, while no significant differences in the muscle were observed between groups (p?

  10. Acute toxicity of organochlorine insecticide endosulfan to the giant freshwater prawn Macrobrochium rosenbergii

    NASA Astrophysics Data System (ADS)

    Dai, Xilin; Xiong, Zhaodi; Xie, Jian; Ding, Fujiang

    2014-01-01

    Endosulfan, an organochlorine pesticide, is highly toxic and effective at controlling pests in agriculture, horticulture, and public health programs. In this study, static bioassays were used to evaluate the toxicity of endosulfan to freshwater prawns ( Macrobrachium rosenbergii) of various lengths (1.5±0.03, 4±0.08, and 7±0.06 cm). Additionally, the activities of peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase, acetylcholinesterase (AChE), and Na+/K+-ATPase were analyzed to reflect the effects of endosulfan exposure. The 96 h LC50 of endosulfan for prawns 1.5, 4, and 7 cm long were 1.86, 4.53, and 6.09 ?g/L, respectively, improved tolerance to endosulfan with growth. The POD activities of test organisms exposed to low concentrations of endosulfan were inhibited, indicating the presence of oxygen damaged tissue. Moreover, a notable decrease in AChE activity was observed due to overstimulation of neurotransmission, which might result in abnormal behavior. The effect caused by endosulfan on phosphatase production in the hepatopancreas of prawns 1.5, 4, and 7 cm long was different because the ability of nonspecific immune regulation increased with growth. The 96 h LC50 values obtained in this study could be used in the formulation of water-quality criteria in China. Moreover, the changes in enzymes activities of M. rosenbergii under stress of endosulfan could be applied in the establishment of early warning indicators for bio-safety.

  11. Sex and the Syndrome: Individual and Population Consistency in Behaviour in Rock Pool Prawn Palaemon elegans

    PubMed Central

    Chapman, Ben B.; Hegg, Alexander; Ljungberg, Peter

    2013-01-01

    Animal personality has been widely documented across a range of species. The concept of personality is composed of individual behavioural consistency across time and between situations, and also behavioural trait correlations known as behavioural syndromes. Whilst many studies have now investigated the stability of individual personality traits, few have analysed the stability over time of entire behavioural syndromes. Here we present data from a behavioural study of rock pool prawns. We show that prawns are temporally consistent in a range of behaviours, including activity, exploration and boldness, and also that a behavioural syndrome is evident in this population. We find correlations between many behavioural traits (activity, boldness, shoaling and exploration). In addition, behavioural syndrome structure was consistent over time. Finally, few studies have explicitly studied the role of sex differences in personality traits, behavioural consistency and syndrome structure. We report behavioural differences between male and female prawns but no differences in patterns of consistency. Our study adds to the growing literature on animal personality, and provides evidence showing that syndromes themselves can exhibit temporal consistency. PMID:23555034

  12. Monitoring the spreading of the Amazon freshwater plume by MODIS, SMOS, Aquarius and TOPAZ

    NASA Astrophysics Data System (ADS)

    Korosov, Anton; Counillon, Francois; Johannessen, Johnny A.

    2015-04-01

    A synergistic tool for studying the Amazon River Plume dynamics based on a novel algorithm for deriving sea surface salinity (SSS) from MODIS reflectance data together with SSS data from the SMOS and Aquarius satellites and the TOPAZ data assimilation system is proposed. The new algorithm is based on a neural network to relate spectral remote sensing reflectance measured by MODIS with SSS measured by SMOS in the Amazon river plume. The algorithm is validated against independent in-situ data and is found to be valid in the range of SSS from 29 to 35 psu, for the period of highest rates of Amazon River discharge with RMSE=0.79 psu and R2=0.84. Monthly SSS fields were reconstructed from the MODIS data for late summers from 2002 to 2012 at a 10 km resolution and compared to surface currents and SSS derived from the TOPAZ reanalysis system. The two datasets reveal striking agreement, suggesting that the TOPAZ system could be used for a detailed study of the Amazon River plume dynamics. Both the position and speed of the North Brazilian Current as well as the spreading of the Amazon River plume are monitored. In particular a recurrent mechanism was observed for the spreading of the rivers plumes, notably that the fresh water is usually advected towards the Caribbean Sea by the North Brazilian Current but get diverted into the tropical Atlantic when North Brazilian Current rings are shed. Innovative method for satellite data temporal morphing based on remotely sensed surface ocean currents allow to derive SSS at unprecedented spatial (1km) and temporal (1 day) resolution.

  13. Seabed dynamics of the inner Amazon continental shelf: temporal and spatial variability of surficial strata

    Microsoft Academic Search

    Steven A. Kuehl; Thomas D. Pacioni; James M. Rine

    1995-01-01

    The continental shelf southeast and northwest of the Amazon River mouth is overlain by a sediment layer of about a meter in thickness, characterized by 210Pb profiles consisting of one or more segments with nearly-uniform excess activity. Uniform 210Pb activity profiles in shelf environments commonly are a result of intense biological reworking of sediments; however, biological activity is minimal in

  14. Penaeus orientolis prawn freshness rapid determination method based on electronic nose and non-linear stochastic resonance technique.

    PubMed

    Wei, Liu; Yuanyuan, Han; Yanping, Cai; Jiaojiao, Jin; Guohua, Hui

    2015-01-01

    In this paper, Penaeus orientolis prawn freshness rapid determination method using electronic nose (e-nose) and non-linear data processing technique is studied. E-nose responses to prawns stored at 4 °C are measured. Meanwhile, physical/chemical indexes (firmness, pH, total volatile basic nitrogen (TVB-N), total viable count (TVC), and human sensory evaluation) are examined to provide freshness references for e-nose analysis. E-nose measurement data is analyzed by principal component analysis (PCA), stochastic resonance (SR), and double-layered cascaded serial stochastic resonance (DCSSR). PCA partially discriminates prawns under different storage time. SR and DCSSR signal-to-noise ratio (SNR) spectrum eigen values discriminate prawns successfully. Multi-variables regressions (MVR) are conducted between physical/chemical indexes and SR/DCSSR output SNR minimal (SNR-Min) values. Results indicate that SNR-Min values present more significant linearity relation with physical/chemical indexes. Prawn freshness forecasting model is developed via Harris fitting regression on DCSSR SNR-Min values. Validating experiments demonstrate that forecasting accuracy of this model is 94.29%. PMID:25551520

  15. A Healthier Amazon Jungle (NYT) 417 words

    E-print Network

    Lopez-Carr, David

    deforestation in a decade. The health of the Amazon is a global concern because the forest soaks up greenhouse gases, which lessens global warming. Deforestation means the Amazon could eventually become too small

  16. Are severe droughts in western Amazon here to stay?

    NASA Astrophysics Data System (ADS)

    Fernandes, K.; Goddard, L.; Baethgen, W.; Pinedo-Vasquez, M.

    2012-12-01

    Droughts do not immediately come to mind when one thinks of climate extremes that impact western Amazon (WA), where luscious green rainforest predominates. However, droughts in recent years have made the news due to their large socio-economic impacts, such as increased occurrence of fires, respiratory problems related to smoke and reduced fisheries and fluvial transportation due to low river levels. The two most recent notorious droughts in the region were those of 2005 and 2010, both referred to as a "100-year drought". Whether the severity of recent droughts is related to low frequency natural climate variability and/or climate change is not clear. To assess the relative importance of different modes of temporal variability on WA precipitation we calculate the dry season months (JAS) Standardized Precipitation Index (SPI) from two gridded precipitation datasets over a period of 76 years and statistically decompose them into interannual, inter-decadal and trend components. The same analysis is done for the Negro River standardized minimum water level, a major Amazon tributary for which nearly 100 years of data can be obtained. As we will show, the majority of the total variance of SPI from both precipitation datasets and minimum river water level is explained by internannual variability, and the least by trend. Additionally, the dry season precipitation variability in this region is shown to respond to anomalous North Tropical Atlantic (NTA) sea surface temperature (SST), especially over the last 15 years. To explore whether the different time scales of JAS SPI show similar relationship over the longer time period available (76 yrs), the partitioned time series are correlated to averaged April through September tropical SST. We find the strongest relationship to be with the north-south tropical Atlantic SST gradient (not the NTA alone) in both interannual and inter-decadal time scales, whereas the variability of tropical Pacific SST, know to affects eastern Amazon precipitation, shows no significant relationship to WA JAS SPI variability.

  17. Modelling sustainable international tourism demand to the Brazilian Amazon

    Microsoft Academic Search

    Jose Angelo Divino; Michael Mcaleer

    2009-01-01

    The Amazon rainforest is one of the world's greatest natural wonders and holds great importance and significance for the world's environmental balance. Around 60% of the Amazon rainforest is located in the Brazilian territory. The two biggest states of the Amazon region are Amazonas (the upper Amazon) and Pará (the lower Amazon), which together account for around 73% of the

  18. Effect of saponin on hematological and immunological parameters of the giant freshwater prawn, Macrobrachium rosenbergii

    Microsoft Academic Search

    Shinn-Pyng Yeh; Chun-Hung Liu; Tzeng-Gan Sung; Pai-Po Lee; Winton Cheng

    2006-01-01

    Giant freshwater prawns, Macrobrachium rosenbergii (17.9±2.7 g), exposed to different concentrations of saponin at 0, 0.3, 0.6, 0.9 and 1.2 mg l?1 for 168 h were examined for osmolality, electrolyte levels, oxyhemocyanin, protein levels, acid-base balance status, total hemocyte count (THC), phenoloxidase activity, and respiratory bursts. Hemolymph oxyhemocyanin, protein, and pO2 were inversely related to the saponin concentration. Hemolymph oxyhemocyanin, protein, pO2, pCO2,

  19. The ecdysteroid titer in the female prawn, Macrobrachium rosenbergii during the molt cycle 

    E-print Network

    Newitt, Richard Allen

    1981-01-01

    of labeled and unlabeled ecdysone through purification. Experiment 49: Ecdysteroid titer of prawn carcasses with determination of recovery. 38 39 TABLE 5. Experiment 410: HPLC analysis of zone E from TLC separations 45 TABLE 6. Experiment iI11... on scheme for ecdysteroi ds from car cass or ovaries Molt cycle stages A, 8, and C Molt cycle stages 0 and D I 0 Molt cycle stages Dl and Dl II III Molt cycle stage D3. 15 22 26 28 FIGURE 9: Contamination of HPLC system with ecdyster aids...

  20. Amazon RainForest Fires

    Microsoft Academic Search

    Robert L. Sanford; Juan Saldarriaga; Kathleen E. Clark; Christopher Uhl; Rafael Herrera

    1985-01-01

    Charcoal is common in the soils of mature rain forests within 75 kilometers of San Carlos de Rio Negro in the north central Amazon Basin. Carbon-14 dates of soil charcoal from this region indicate that numerous fires have occurred since the mid-Holocene epoch. Charcoal is most common in tierra firme forest Oxisols and Ultisols and less common in caatinga and

  1. 4, 99123, 2007 Amazon carbon

    E-print Network

    Boyer, Edmond

    , suggested much larger estimates for tropical forest carbon sequestration in the Ama- zon BasinBGD 4, 99­123, 2007 Amazon carbon balanc J. Lloyd et al. Title Page Abstract Introduction Discussions is the access reviewed discussion forum of Biogeosciences An airborne regional carbon balance

  2. Amazon Deforestation and Climate Change

    Microsoft Academic Search

    J. Shukla; C. Nobre; P. Sellers

    1990-01-01

    A coupled numerical model of the global atmosphere and biosphere has been used to assess the effects of Amazon deforestation on the regional and global climate. When the tropical forests in the model were replaced by degraded grass (pasture), there was a significant increase in surface temperature and a decrease in evapotranspiration and precipitation over Amazonia. In the simulation, the

  3. Potential hydrologic changes in the Amazon by the end of the 21st century and the groundwater buffer

    NASA Astrophysics Data System (ADS)

    Pokhrel, Yadu N.; Fan, Ying; Miguez-Macho, Gonzalo

    2014-08-01

    This study contributes to the discussions on the future of the Amazon rainforest under a projected warmer-drier climate from the perspectives of land hydrology. Using IPCC HadGEM2-ES simulations of the present and future Amazon climate to drive a land hydrology model that accounts for groundwater constraint on land drainage, we assess potential hydrologic changes in soil water, evapotranspiration (ET), water table depth, and river discharge, assuming unchanged vegetation. We ask: how will ET regimes shift at the end of the 21st century, and will the groundwater help buffer the anticipated water stress in some places-times? We conducted four 10 yr model simulations, at the end of 20th and 21st century, with and without the groundwater. Our model results suggest that, first, over the western and central Amazon, ET will increase due to increased potential evapotranspiration (PET) with warmer temperatures, despite a decrease in soil water; that is, ET will remain PET or atmospheric demand-limited. Second, in the eastern Amazon dry season, ET will decrease in response to decreasing soil water, despite increasing PET demand; that is, ET in these regions-seasons will remain or become more soil water or supply-limited. Third, the area of water-limited regions will likely expand in the eastern Amazonia, with the dry season, as indicated by soil water store, even drier and longer. Fourth, river discharge will be significantly reduced over the entire Amazon but particularly so in the southeastern Amazon. By contrasting model results with and without the groundwater, we found that the slow soil drainage constrained by shallow groundwater can buffer soil water stress, particularly in southeastern Amazon dry season. Our model suggests that, if groundwater buffering effect is accounted for, the future Amazon water stress may be less than that projected by most climate models.

  4. Immunomodulatory effect of Withania somnifera supplementation diet in the giant freshwater prawn Macrobrachium rosenbergii (de Man) against Aeromonas hydrophila.

    PubMed

    Harikrishnan, Ramasamy; Balasundaram, Chellam; Jawahar, Sundaram; Heo, Moon-Soo

    2012-01-01

    The effect of Withania somnifera extract supplementation diets on innate immune response in giant freshwater prawn Macrobrachium rosenbergii (de Man) against Aeromonas hydrophila was investigated. The bacterial clearance efficiency significantly increased in prawn fed with 0.1% and 1.0% doses of W. somnifera supplementation diet against pathogen from weeks 1-4 as compared to the control. The innate immune parameters such as, phenoloxidase activity, superoxide anion level, superoxide dismutase activity, nitrate, and nitrite concentrations were significantly enhanced in prawn fed with 0.1% and 1.0% doses of W. somnifera supplementation diet from weeks 1-4 against pathogen. The total hemocyte counts (THC) significantly increased in prawn fed with 0.1% and 1.0% doses diet from weeks 1-4 against pathogen as compared to the control. These results strongly suggested that administration of W. somnifera through supplementation diet positively enhances the innate immune system and enhanced survival rate in M. rosenbergii against A. hydrophila infection. PMID:22118967

  5. Toxicity of Drilling Waste and Its Impact on Gill Structure of Post Larvae of Tiger Prawn (Penaeus monodon)

    Microsoft Academic Search

    Agoes Soegianto; Bambang Irawan; Mochammad Affandi

    The study to evaluate the toxicity of used drilling muds (drilling wastes) and their impact on gill structure of the post larvae of tiger prawn Penaeus monodon has been done. The results showed that the 96 h LC50 of used drilling muds ranged from 30740 and 78271 ppm SPP. All toxicity values considered to be above the standard of Indonesian

  6. Effect of crude oil petroleum hydrocarbons on protein expression of the prawn Macrobrachium borellii.

    PubMed

    Pasquevich, M Y; Dreon, M S; Gutierrez Rivera, J N; Vázquez Boucard, C; Heras, H

    2013-05-01

    Hydrocarbon pollution is a major environmental threat to ecosystems in marine and freshwater environments, but its toxicological effect on aquatic organisms remains little studied. A proteomic approach was used to analyze the effect of a freshwater oil spill on the prawn Macrobrachium borellii. To this aim, proteins were extracted from midgut gland (hepatopancreas) of male and female prawns exposed 7 days to a sublethal concentration (0.6 ppm) of water-soluble fraction of crude oil (WSF). Exposure to WSF induced responses at the protein expression level. Two-dimensional gel electrophoresis (2-DE) revealed 10 protein spots that were differentially expressed by WSF exposure. Seven proteins were identified using MS/MS and de novo sequencing. Nm23 oncoprotein, arginine methyltransferase, fatty aldehyde dehydrogenase and glutathione S-transferase were down-regulated, whereas two glyceraldehyde-3-phosphate dehydrogenase isoforms and a lipocalin-like crustacyanin (CTC) were up-regulated after WSF exposure. CTC mRNA levels were further analyzed by quantitative real-time PCR showing an increased expression after WSF exposure. The proteins identified are involved in carbohydrate and amino acid metabolism, detoxification, transport of hydrophobic molecules and cellular homeostasis among others. These results provide evidence for better understanding the toxic mechanisms of hydrocarbons. Moreover, some of these differentially expressed proteins would be employed as potential novel biomarkers. PMID:23570752

  7. Temporal and spatial patterns in recruitment of three penaeid prawns in Moreton Bay, Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Courtney, A. J.; Masel, J. M.; Die, D. J.

    1995-10-01

    The size at recruitment, temporal and spatial distribution, and abiotic factors influencing abundance of three commercially important species of penaeid prawns in the sublittoral trawl grounds of Moreton Bay (Queensland, Australia) were compared. Metapenaeus bennettae and Penaeus plebejus recruit to the trawl grounds at sizes which are relatively small (14-15 mm carapace length, CL) and below that at which prawns are selected for, and retained, in the fleet's cod-ends. In contrast, Penaeus esculentus recruit at the relatively large size of 27 mm CL from February to May, well above the size ranges selected for. Recruitment of M. bennettae extends over several months, September-October and February-March, and was thus likely to be bi-annual, while the recruitment period of P. plebejus was distinct, peaking in October-November each year. Size classes of M. bennettae were the most spatially stratified of the three species. Catch rates of recruits were negatively correlated with depth for all three species, and were also negatively correlated with salinity for M. bennettae.

  8. Tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros during methylparathion, carbaryl and aldrin exposure.

    PubMed

    Reddy, M S; Rao, K V

    1991-01-01

    Changes in midgut gland and muscle tissue glycolytic potentials of penaeid prawn, Metapenaeus monoceros following exposure to methylparathion, carbaryl and aldrin were studied. A decrease in total carbohydrates, glycogen and pyruvate and an increase in lactate levels were observed. An increase in phosphorylase 'a' and aldolase activity levels suggested increased formation of trioses during selected insecticide toxicity. The decrease in the lactate dehydrogenase activity levels and an increase in the lactate content indicative of reduced mobilization of pyruvate into the citric acid cycle. During selected insecticide exposure, the prawn tissues adopting some sort of regulatory pathways such as enhanced glycolysis and a shift of metabolic emphasis from aerobiosis to anaerobiosis. All the above mentioned changes were more pronounced in the midgut gland compared to muscle tissue. The per cent decrease or increase are more under aldrin exposure followed by carbaryl and methylparathion exposure. The selected insecticides in the present investigation, though belongs to different representative groups, but appears to be neurotoxic leading to disturbances in the carbohydrate catabolism. PMID:1830481

  9. Impact of TBT on the vitellogenesis and sex hormones in freshwater prawn Macrobrachium rosenbergii (De Man, 1879)

    PubMed Central

    2013-01-01

    Background Tributyltin (TBT) is a ubiquitous persistent xenobiotic that can be found in freshwater, estuarine and marine ecosystem. TBT is a strong endocrine disrupting compound (EDC) that can cause toxic threat to aquatic organisms. Imposex, sexual deformities and endocrine dysfunctions are the causes of TBT to most of the aquatic organisms. Effect of TBT on the vitellogenesis and sex hormonal changes in Macrobrachium rosenbergii has never been reported. Hence, the present investigation was undertaken to find out the impact of TBT on histological changes in the different reproductive tissues, sex hormonal alterations and level of biomarkers like vitellogenin and vitellin in M. rosenbergii. Results The present investigation documents the possible impact of tributyltin (TBT) on the vitellogenesis in freshwater female prawn M. rosenbergii. TBT at 10 ng/l, 100 ng/l and 1000 ng/l concentrations were exposed individually to prawns for a period of three months. At higher concentration of 1000 ng/l, the ovarian development was arrested and ovary remained at spent stage. At lower concentration of TBT (10 ng/l), the development proceeded up to early vitellogenic stage. At intermediate concentration of 100 ng/l TBT, the ovary remained at pre vitellogenic stage and thereafter no development was noticed. Histological results indicated the normal ovarian development with vitellogenic oocytes, filled with yolk globules in control prawn. On the other hand, the TBT treated groups showed reduction in yolk globules, fusion of developing oocytes and abundance of immature oocytes. Immunofluorescence staining denoted the remarkable reduction in vitellin content in ovary of TBT treated prawn. Hence, TBT had conspicuously inhibited the vitellogenesis by causing hormonal imbalance in M. rosenbergii. Conclusion TBT had notably inhibited the vitellogenesis due to hormonal imbalance. This endocrine dysfunction ultimately impaired the oogenesis in the freshwater female prawn M. rosenbergii. PMID:23634699

  10. Spatial clustering and longitudinal variation of Anopheles darlingi (Diptera: Culicidae) larvae in a river of the Amazon: the importance of the forest fringe and of obstructions to flow in frontier malaria.

    PubMed

    Barros, F S M; Arruda, M E; Gurgel, H C; Honório, N A

    2011-12-01

    Deforestation has been linked to a rise in malaria prevalence. In this paper, we studied longitudinally 20 spots, including forested and deforested portions of a temporary river in a malarigenous frontier zone. Larval habitat parameters influencing distribution of Anopheles darlingi (Diptera: Culicidae) larvae were studied. We observed that larvae were clustered in forested-deforested transitions. For the first time in the literature, it was verified that parameters determining larval distribution varied from deforested to forested areas. The proximity to human dwellings was also a significant factor determining distribution, but larvae was most importantly associated with a previously undescribed parameter, the presence of small obstructions to river flow, such as tree trunks within the river channel, which caused pooling of water during the dry season ('microdams'). In deforested areas, the most important factor determining distribution of larvae was shade (reduced luminance). Larvae were absent in the entire studied area during the wet season and present in most sites during the dry season. During the wet-dry transition, larvae were found sooner in areas with microdams, than in other areas, suggesting that flow obstruction prolongs the breeding season of An. darlingi. Adult mosquito densities and malaria incidence were higher during the dry season. Our data correlate well with the published literature, including the distribution of malaria cases near the forest fringes, and has permitted the creation of a model of An. darlingi breeding, where preference for sites with reduced luminance, human presence and microdams would interact to determine larval distribution. PMID:21729392

  11. Biogeochemical Process in an Amazon Basin Floodplain - Curuai Várzea, Brazil

    NASA Astrophysics Data System (ADS)

    Moura, J. M. S.; Victoria, R. L.; Oliveira, E.; Ometto, J. P.; Martinelli, L.

    2014-12-01

    The work was performed during in the Amazon, mainly focusing in the study of a typical floodplain (Lago Grande de Curuai) located on the right bank of the Amazon River. During the low water phase, the mean concentration of SS was 320,0 ±43,6 mg L-1, which in turn, is 13-fold the mean concentration (24,5 ±3,9 mg L-1) measured during the high water phase. During the rising water phase the concentration of SS decreased significantly to 83,0 ±21,3 mg L-1 Concentration of DOC were very similar (~4 mg L-1) along the rising, high, and falling water phases, and increased significantly during the low water phase reaching mean value equal to 6,4±0,4 mg L-1. The C:N varied from ~7 to 9,2 showing the lowest value during the low water phase and highest values during the rising water. The ?15N values showed similar trend, varying from ~4‰ during the low water phase and reaching the most depleted (<2‰) values during the falling water phase. The carbon isotopic composition varied from -27‰ to -25‰, but the low water phase was not different from the other phases Dissolved and solid compounds suspended in the water of the Curuai Lake showed a very clear seasonal variation in concentrations, elementar and isotopic composition. During the ring water the Amazon River seems to be main source of organic matter and ions to floodplain. Inversely, primary production looks to be an important factor driving changes in the organic matter characteristics during low water phase

  12. REPRODUCTIVE MECHANISMS IN THE GIANT FRESHWATER PRAWN, MACROBRACHIUM ROSENBERGII AND COOPERATIVE RESEARCH TO IMPROVE SEED PRODUCTION TECHNOLOGY IN THE MEKONG DELTA REGION OF VIETNAM

    Microsoft Academic Search

    Marcy N. Wilder; Wei-Jun Yang; Do Thi Thanh Huong; Masachika Maeda

    The giant freshwater prawn, Macrobrachium rosenbergii , is a commercially important species of crustacean cultured extensively throughout Southeast Asia. In Vietnam, where Japan International Research Center for Agricultural Sciences (JIRCAS) is currently implementing a comprehensive project entitled \\

  13. Controls over the strontium isotope composition of river water

    Microsoft Academic Search

    M. R. Palmer; J. M. Edmond

    1992-01-01

    Strontium concentrations and isotope ratios have been measured in river and ground waters from the Granges, Orinoco, and Amazon river basins. When compared with major element concentrations, the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments: (1) typical drainage basins containing limestones, evaporites,

  14. Controls over the strontium isotope composition of river water

    Microsoft Academic Search

    M. R. Palmer; J. M. Edmond

    1992-01-01

    Strontium concentrations and isotope ratios have been measured in river and ground waters from the Ganges, Orinoco, and Amazon river basins. When compared with major element concentrations, the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments: 1. (1) \\

  15. Hydrology and climate in the southwestern Amazon basin (Bolivia)

    NASA Astrophysics Data System (ADS)

    Ronchail, J.; Bourrel, L.; Maurice-Bourgoin, L.; Vauchel, P.; Cochonneau, G.; Guyot, J. L.; Phillips, L.; Castro, A.

    2003-04-01

    The variability of the runoff of the Bolivian tributaries of the Madeira River, the greatest southern affluent of the Amazon R., is of major importance for the riparian people safety and for the economic development of the region. We investigated whether the discharge of these rivers is predictable or not, using the Sea Surface Temperatures Anomalies (SSTAs) in the Equatorial Pacific and in the Tropical Atlantic oceans. The hydrological variability is studied using daily river discharge data of 3 tributaries: the Rio Beni in Rurrenabaque, the Rio Ichilo in Puerto Villaroel and the Mamoré River in Puerto Varador, respectively representative of the Andes, the Andean Piedmont and the lowlands. This information has been collected and criticized in the mark of successive Bolivian - French conventions. The hydrological response of the Andean river is out of phase with that of the piedmont and plain rivers. The Rio Beni in Rurrenabaque experiments high runoff during La Niña events and during cool (warm) events in the northern (southern) tropical Atlantic. On the contrary, the Ichilo and Mamoré Rivers and inundation data show that high runoff are more frequent during El Niño events and when the southern tropical Atlantic Ocean is cooler than normally. 30% of the Beni R. discharge variability is explained by the ENSO events and 25% by the SSTAs in the tropical Atlantic. In the Andean piedmont and in the lowlands, the ENSO explains 45% of the discharges, but differences in series lengths may also contribute to this better result. On the contrary, the relationship with the southern tropical Atlantic is only a tendency and is not statistically significant. To conclude, the SSTAs in the tropical oceans do not allow a prediction of the discharge variability of the Bolivian tributaries of the Madeira River but they contribute to their comprehension. The present results, different for Andean and Piedmont or lowlands tributaries, are consistent with those relative to the ENSO and tropical Atlantic related rainfall anomalies in both regions of Bolivia.

  16. 9 Evaluating the effects of a turtle excluder device (TED) and square mesh codend bycatch reduction device (BRD) in Queensland's deepwater eastern king prawn (Penaeus plebejus) trawl fishery

    Microsoft Academic Search

    A. J. Courtney; M. J. Campbell; M. L. Tonks; D. P. Roy; S. W. Gaddes; P. M. Kyne; K. E. Chilcott

    9.1 ABSTRACT This chapter described the bycatch and quantified the effects of a turtle excluder device (TED) and square mesh codend bycatch reduction device (BRD) on the catch rates of bycatch and targeted prawns in the deepwater eastern king prawn fishery off the south-east Queensland coast, based on a 10-day research charter. A total of 227 taxa were recoded in

  17. Effects of dietary administration of water hyacinth (Eichhornia crassipes) extracts on the immune responses and disease resistance of giant freshwater prawn, Macrobrachium rosenbergii.

    PubMed

    Chang, Chin-Chyuan; Tan, Hui-Ching; Cheng, Winton

    2013-07-01

    The hot-water extract of Eichhornia crassipes leaves (ECE) was produced and incorporated into the diet of the prawn, Macrobrachium rosenbergii, as an immunostimulant. Survival rates of prawn against Lactococcus garvieae, and its immune parameters including the total haemocyte count (THC), different haemocyte count (DHC), phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, transglutaminase (TG) activity, haemolymph coagulation time, and phagocytic activity and clearance efficiency against L. garvieae by M. rosenbergii were determined when prawn (23.0 ± 2.8 g) were fed ECE-containing diets at 0, 1.0, 2.0 and 3.0 g kg(-1). Prawn fed a diet containing ECE at 2.0 and 3.0 g kg(-1) for 12 days showed significantly increased THC, HC, GC, PO activity, RBs, SOD activity, GPx activity, and TG activity, and a significantly decreased coagulation time. The phagocytic activity and clearance efficiency against L. garvieae of prawn fed the ECE-containing diets at 1.0, 2.0, and 3.0 g kg(-1) were significantly higher than those of prawn fed the control diet at 3-12 days. Survival rates of M. rosenbergii fed the diet containing ECE at concentrations of 2 and 3 g kg(-1) were significantly higher than those fed the control diet after challenge with L. garvieae for 48-144 h. The relative percentage survival of prawn fed the 1.0, 2.0, and 3.0 g kg(-1) ECE-containing diets for 12 days were 17.5%, 39.1%, and 52.2%. It was concluded that the ECE can be used as an immunostimulant for prawn through dietary administration to enhance immune responses and resistance of M. rosenbergii against L. garvieae. PMID:23603238

  18. Assesing Hydrophysical/Enivornmenal impacts by Dams in the Amazon (fluvial) Basin

    NASA Astrophysics Data System (ADS)

    Wight, C.; Latrubesse, E. M.

    2014-12-01

    Growing demands from human activities are increasing the pressure and impacts on the Amazon River basin. Covering almost 40% of South America, the Amazon River basin's health is of global importance. With tributaries in 6 different countries, the anthropogenic impacts on this large system are complex and hard to synthesize. However to better understand large system responses to human impacts such an analysis is called for. Our objective is to organize a rigorous analysis of the potential hydro-physical impacts of dams on the major sub-basins of the Amazon. We are incorporating existing data of sediment fluxes, deforestation and land-use land-change to include the entire extent of the basin as defined by the fluvial unit. In addition, we will be analyzing the spatial distributions of dams (planned, under construction, and constructed) within each sub-basin. Our preliminary results have used statistical analysis and remote sensing to calculate the extent of deforestation on fluvial regimes of the legal Amazon and concentrated to identify the potential disruptions of sediment fluxes. Combining the spatial distributions of dam sites, and deforestation per sub-basin we will develop a system to interpret land-use and land-change per catchment. This in turn will allow us to better predict changes in the fluvial regimes and allow for comparisons of vulnerability.

  19. Genetic variability in three Amazon parrot species.

    PubMed

    Lopes, I F; Del Lama, M A; Del Lama, S N

    2007-12-01

    Parrots of the genus Amazona are among the most threatened species of the Order Pscittaciformes. This work describes allozyme polymorphisms in three Amazon parrot species--the Blue-fronted Amazon (Amazona aestiva), the Orange-winged Amazon (Amazona amazonica), and the Festive Amazon (Amazona festiva) -, and provides useful data for the evaluation of their genetic variability. We electrophoretically analyzed blood samples from 68 wild-caught individuals, maintained in captivity in three Brazilian zoos. Eight of the ten studied enzyme loci exhibited polymorphism. Glucosephosphate isomerase (Gpi) proved to be a diagnostic locus for the identification of these Amazon species. The expected average heterozygosity of the Blue-fronted Amazon (0.060) differed significantly from the expected heterozygosities of the Orange-winged Amazon and the Festive Amazon (0.040 and 0.039, respectively). This result was discussed as a consequence of hybridization between two geographic A. aestiva subspecies, and alternatively as a particular trait of this species. Genetic variability of the Blue-fronted Amazon compared to birds in general is not low on a species-wide level, despite the fact that this parrot is one of the most illegally traded species. Allozyme analysis proved to be an useful tool in monitoring the genetic variation within the genus Amazona and can be applied in the management program of other threatened species of this genus. PMID:18278355

  20. Structure and floristic composition of flood plain forests in the Peruvian Amazon, II. The understorey of restinga forests

    Microsoft Academic Search

    Gustav Nebel; Jens Dragsted; Jerome K. Vanclay

    2001-01-01

    Structure and floristic composition of small trees and shrubs (1.5 m height to 10 cm diameter at breast height was described in two flood plain forests of the lower Ucayali river, Peruvian Amazon. The forests were of the high and low restinga type, on an annual average flooded around 1 and 2 months, respectively. The soils were nutrient rich entisols,

  1. Forest dynamics in flood plain forests in the Peruvian Amazon: effects of disturbance and implications for management

    Microsoft Academic Search

    Gustav Nebel; Lars Peter Kvist; Jerome K. Vanclay; Héctor Vidaurre

    2001-01-01

    Forest dynamics were studied from 1993 to 1997 for individuals ?10cm DBH in nine 1ha permanent sample plots. They were established in natural flood plain forests located on the lower Ucayali river in the Peruvian Amazon. After inventories of three plots in each of three forest types, a light and a heavy felling treatment were applied to each of the

  2. Xiphidorus amazonensis n. sp. (Nematoda: Longidoridae) from the Brazilian Amazon Basin.

    PubMed

    Uesugi, C H; Huang, C S; Cares, J E

    1985-07-01

    Xiphidorus amazonensis n. sp. was found in the rhizospheres of Jatropha curcas, Musa sp., Anona muricata, Cassia tora, Panicum laxum, Paspalum fasciculatum, Aeschynomene sensitiva, Saccharum officinarum, Manihot esculenta, Abelmoschus esculentus, Tamarindus indica, Mangifera indica, Vigna unguiculata, Zea mays, Commelina sp., Cyperus rotundus, Fimbristylis miliacea, Citrus sinensis, and Eichhornia crassipes on the Amazon River island of Xiborena, approximately 40 km southeast of Manaus, capital of the State of Amazonas. The type habitat is flooded annually for about 6 months by the Amazon River. Xiphidorus amazonensis n. sp. differs from the closely related species Xiphidorus yepesara Monteiro, 1976 by the larger size, by a, b, and c values, and by the rounded tail terminus. It also resembles Xiphidorus tucumanensis Chaves and Coomans, 1984, but can be distinguished by its larger size, larger a, b, and c values, more conical female tail, bilobed amphidial pouch, and the presence of a spermatheca full of sperm. PMID:19294098

  3. Xiphidorus amazonensis n. sp. (Nematoda: Longidoridae) from the Brazilian Amazon Basin

    PubMed Central

    Uesugi, C. H.; Huang, C. S.; Cares, J. E.

    1985-01-01

    Xiphidorus amazonensis n. sp. was found in the rhizospheres of Jatropha curcas, Musa sp., Anona muricata, Cassia tora, Panicum laxum, Paspalum fasciculatum, Aeschynomene sensitiva, Saccharum officinarum, Manihot esculenta, Abelmoschus esculentus, Tamarindus indica, Mangifera indica, Vigna unguiculata, Zea mays, Commelina sp., Cyperus rotundus, Fimbristylis miliacea, Citrus sinensis, and Eichhornia crassipes on the Amazon River island of Xiborena, approximately 40 km southeast of Manaus, capital of the State of Amazonas. The type habitat is flooded annually for about 6 months by the Amazon River. Xiphidorus amazonensis n. sp. differs from the closely related species Xiphidorus yepesara Monteiro, 1976 by the larger size, by a, b, and c values, and by the rounded tail terminus. It also resembles Xiphidorus tucumanensis Chaves and Coomans, 1984, but can be distinguished by its larger size, larger a, b, and c values, more conical female tail, bilobed amphidial pouch, and the presence of a spermatheca full of sperm. PMID:19294098

  4. A remote sensing/geochronological study of coastal morphology associated with episodic Amazon sediment supply

    E-print Network

    Lee, Michael Touchet

    2000-01-01

    of Advisory Committee: Dr. Mead Allison A combination of remotely sensed change detection surveys and geochronology (e. g. , ' Th, Be, ' Pb, and" Cs) ofsedimentcoresinthree separateareasin Braziland French Guiana are used to develop an understanding of how.... Sediment deposits on the shareface and inner shelf have been identified on major river shelves such as the Ganges-Brahmaputra (Kuehl et al. , 1989), Rhine (de Haas and Eisma, 1993), Yangtze (McKee et al. , 1983), and the Amazon (Allison et al. , 1994...

  5. Phospholipid fatty acid composition of hepatopancreatic brush-border membrane vesicles from the prawn Penaeus japonicus.

    PubMed

    Muriana, F J; Ruiz-Gutierrez, V; Blaya, J A; Bolufer, J

    1995-01-01

    Brush-border membrane vesicles (BBMV) were isolated from prawn hepatopancreas as we previously described (Muriana et al (1993) J Biochem 113, 625-629). The characterization of hepatopancreatic BBMV (hBBMV) by monitoring the activity of marker enzymes indicated a relatively pure apical membrane preparation reduced in basolateral contamination. Phospholipid composition of hBBMV was examined by the Iatroscan TLC/FID technique, whereas the fatty acid profile of phospholipids was examined by capillary gas chromatography. Phosphatidylcholine and phosphatidylethanolamine are the principal phospholipids of these membranes. The major fatty acids of phospholipids are palmitic (16:0), palmitoleic (16:1n-7), stearic (18:0), oleic (18:1n-9), eicosapentaenoic (20:5n-3) and docosapentaenoic (22:5n-3) acids. Individual phospholipids are characterized by distinct fatty acid compositions, but display a similar ratio of unsaturated-to-saturated fatty acids and a similar unsaturation index. PMID:7647111

  6. Transcriptomics of a Giant Freshwater Prawn (Macrobrachium rosenbergii): De Novo Assembly, Annotation and Marker Discovery

    PubMed Central

    Jung, Hyungtaek; Lyons, Russell E.; Dinh, Hung; Hurwood, David A.; McWilliam, Sean; Mather, Peter B.

    2011-01-01

    Background Giant freshwater prawn (Macrobrachium rosenbergii or GFP), is the most economically important freshwater crustacean species. However, as little is known about its genome, 454 pyrosequencing of cDNA was undertaken to characterise its transcriptome and identify genes important for growth. Methodology and Principal Findings A collection of 787,731 sequence reads (244.37 Mb) obtained from 454 pyrosequencing analysis of cDNA prepared from muscle, ovary and testis tissues taken from 18 adult prawns was assembled into 123,534 expressed sequence tags (ESTs). Of these, 46% of the 8,411 contigs and 19% of 115,123 singletons possessed high similarity to sequences in the GenBank non-redundant database, with most significant (E value < 1e–5) contig (80%) and singleton (84%) matches occurring with crustacean and insect sequences. KEGG analysis of the contig open reading frames identified putative members of several biological pathways potentially important for growth. The top InterProScan domains detected included RNA recognition motifs, serine/threonine-protein kinase-like domains, actin-like families, and zinc finger domains. Transcripts derived from genes such as actin, myosin heavy and light chain, tropomyosin and troponin with fundamental roles in muscle development and construction were abundant. Amongst the contigs, 834 single nucleotide polymorphisms, 1198 indels and 658 simple sequence repeats motifs were also identified. Conclusions The M. rosenbergii transcriptome data reported here should provide an invaluable resource for improving our understanding of this species' genome structure and biology. The data will also instruct future functional studies to manipulate or select for genes influencing growth that should find practical applications in aquaculture breeding programs. PMID:22174756

  7. Cloning and characterization of two different ficolins from the giant freshwater prawn Macrobrachium rosenbergii.

    PubMed

    Zhang, Xiao-Wen; Wang, Xian-Wei; Huang, Ying; Hui, Kai-Min; Shi, Yan-Ru; Wang, Wen; Ren, Qian

    2014-06-01

    Ficolins, a kind of lectin containing collagen-like and fibrinogen-related domains (FReDs, also known as FBG or FREP), are involved in the first line of host defense against pathogens. In this study, two ficolins, namely, MrFico1 and MrFico2, from the giant freshwater prawn Macrobrachium rosenbergii were identified. In contrast to other ficolins, these two ficolins have no collagen-like domain, but such ficolins contain a coiled region and a FReD domain. Phylogenetic analysis showed that MrFico1 and MrFico2, together with two ficolin-like proteins from Pacifastacus leniusculus, belonged to one group. Quantitative RT-PCR (qRT-PCR) showed that both MrFico1 and MrFico2 were expressed in hepatopancreas, stomach and intestine, with the highest expression in stomach for MrFico1, compared to the highest expression in hepatopancreas for MrFico2. qRT-PCR analysis also showed that MrFico1 was obviously upregulated upon Vibrio anguillarium challenge, while MrFico2 was upregulated after challenged by V. anguillarium or white spot syndrome virus. Bacterium-binding experiment showed that MrFico1 and MrFico2 could bind to different microbes, and sugar-binding assay revealed that these two ficolins could also bind to lipopolysaccharide and peptidoglycan, the glycoconjugates of bacteria surface. Moreover, these two ficolins could agglutinate bacteria in a calcium-dependent manner, and the results of bacteria clearance experiment showed that both ficolins could facilitate the clearance of injected bacteria in the prawn. Our results suggested that MrFico1 and MrFico2 may function as pattern-recognition receptors in the immune system of M. rosenbergii. PMID:24462836

  8. Low-level nocturnal wind maximum over the Central Amazon Basin

    NASA Technical Reports Server (NTRS)

    Greco, Steven; Ulanski, Stanley; Garstang, Michael; Houston, Samuel

    1992-01-01

    A low-level nocturnal wind maximum is shown to exist over extensive and nearly undisturbed rainforest near the central Amazon city of Manaus. Meteorological data indicate the presence of this nocturnal wind maximum during both the wet and dry seasons of the Central Amazon Basin. Daytime wind speeds which are characteristically 3-7 m/s between 300 and 1000 m increase to 10-15 m/s shortly after sunset. The wind-speed maximum is reached in the early evening, with wind speeds remaining high until several hours after sunrise. The nocturnal wind maximum is closely linked to a strong low-level inversion formed by radiational cooling of the rainforest canopy. Surface and low-level pressure gradients between the undisturbed forest and the large Amazon river system and the city of Manaus are shown to be responsible for much of the nocturnal wind increase. The pressure gradients are interpreted as a function of the thermal differences between undisturbed forest and the river/city. The importance of both the frictional decoupling and the horizontal pressure gradient suggest that the nocturnal wind maximum does not occur uniformly over all Amazonia. Low-level winds are thought to be pervasive under clear skies and strong surface cooling and that, in many places (i.e., near rivers), local pressure gradients enhance the low-level nocturnal winds.

  9. River of Venom

    NSDL National Science Digital Library

    BEGIN:VCARD VERSION:2.1 FN:Ken Eklund N:Eklund; Ken ORG:Writerguy REV:2005-04-05 END:VCARD

    1997-02-01

    You, the reader, show up to help study Africanized bees in the Amazon - only to discover the project's director unconscious on the floor. What's going on? Was it an accident or skullduggery? "River of Venom" has three parts. The story begins with Episode One, continues in Episode Two, and wraps up in the Conclusion. Episode One emphasis is medical science and human health. Episode Two requires deductive reasoning. Both episodes present clues and culminate in a mystery question that the reader tries to answer correctly. Facts about the science subjects are integrated into the clue-finding activity for each Episode.

  10. Detection of 3-amino-2-oxazolidinone (AOZ), a tissue-bound metabolite of the nitrofuran furazolidone, in prawn tissue by enzyme immunoassay.

    PubMed

    Cooper, K M; Elliott, C T; Kennedy, D G

    2004-09-01

    Furazolidone, a nitrofuran antibiotic, is banned from use in food animal production within the European Union. Increasingly, compliance with this ban is monitored by use of analytical methods to detect a stable tissue-bound metabolite, 3-amino-2-oxazolidinone (AOZ). Widespread use of furazolidone in poultry and prawns imported into Europe highlighted the urgent need for development of nitrofuran immunoassay screening tests. The first enzyme-linked immunoabsorbant assay for detection of AOZ residues in prawns (shrimps) is now described. Prawn samples were derivatized with o-nitrobenzaldehyde, extracted into ethyl acetate, washed with hexane and applied to a competitive enzyme immunoassay based on a rabbit polyclonal antiserum. Assay limit of detection (LOD) (mean + 3 s) calculated from the analysis of 20 known negative cold and warm water prawn samples was 0.1 microg kg(-1). Intra- and interassay relative standard deviations were determined as 18.8 and 38.2%, respectively, using a negative prawn fortified at 0.7 microg kg(-1). The detection capability (CCbeta), defined as the concentration of AOZ at which 20 different fortified samples yielded results above the LOD, was achieved at fortification between 0.4 and 0.7 microg kg(-1). Incurred prawn samples (n = 8) confirmed by liquid chromatography coupled with tandem mass spectrometry detection to contain AOZ concentrations between 0.4 and 12.7 microg kg(-1) were all screened positive by this enzyme-linked immunoabsorbant assay. Further data are presented and discussed with regard to calculating assay LOD based on accepting a 5% false-positive rate with representative negative prawn samples. Such an acceptance improves the sensitivity of an ELISA and in this case permitted an LOD of 0.05 microg kg(-1) and a CCbeta of below 0.4 microg kg(-1). PMID:15666977

  11. Influence of El Nino and ITCZ on Brazilian River Streamflows

    NASA Astrophysics Data System (ADS)

    Lopes, A.; Dracup, J. A.

    2010-12-01

    This study analyzes effects of climatic phenomena El Nino and ITCZ latitudinal movements on streamflow patterns in major Brazilian river basins: Amazon (north), Araguaia-Tocantins (central-north), Parana (central-south) and Sao Francisco (central-northeast). Multiple correlation between annual streamflows and the NINO 3.4 and North Tropical Atlantic SST indexes (NTA) were analyzed for each river basin using different annual periods in order to account for the delay in streamflow response. The data consists of unimpaired river discharge time series at key points (from the Brazilian National Water Agency (ANA)); normalized yearly averaged NINO3.4 index characterizing El Nino (from NOAA); and NTA index (from NOAA), as a surrogate of the latitudinal movement of the ITCZ, since it is correlated to the Atlantic SST gradient. As a result, each river basin showed a different response. At the Amazon river basin, almost all dry years occurred when NINO3.4 was above average (El Nino years). Moreover, in almost every year when NINO3.4 was below average (La Nina) the streamflows were above average. Thus, it seems that La Nina have strong effects in floods in Amazon river. Moreover, El Nino events seem to be a necessary, but not sufficient condition for low streamflows at Amazon river. A weaker relationship was found for Xingu river basin, since it is probably affected by cold fronts from the south. As the location of river basins changes towards the south, the effect of El Nino events gets weaker as for Araguaia-Tocantins and Sao Francisco river basins. At the Parana river basin, the relationship is reversed. Almost all extreme wet years occurred during El Nino years. The correlation between streamflows and the NTA indexes were very weak for all river basins except for the Amazon. When the NTA anomaly is negative, wet years occurs, since the ITCZ moves southwards and stays longer at that position, increasing rainfall over the Amazon and Northeast of Brazil. In contrast, almost all dry years occurred when the NTA index was positive. Annual streamflows were regressed on climatic indexes NINO 3.4 and NTA. At 95% level of significance, NINO3.4 and NTA indexes are significant variables in predicting streamflows at the Amazon (p=0.01% for NINO3.4 and p=0.30% for NTA) and at the Parana river basins (p=0.23% for NINO3.4 and p=1.11% for NTA). The values of R2 were significant high, 0.59 for Amazon and 0.26 for Parana, compared to very low values for Xingu (0.10), Araguaia-Tocantins (0.06) and Sao Francisco (0.04) river basins. The low correlation at central basins can be explained from the regression coefficients values. The coefficients for NTA index are all negative (except for Xingu river), indicating that negative NTA implies in greater streamflow and vice-versa. However, coefficients for NINO3.4 are negative at the Amazon and positive at Parana which means that negative anomalies (La Nina years) implies in greater streamflows at Amazon and lower streamflows at Parana and vice-versa. Opposite effects of El Nino/La Nina on north and south river basins seems to be neutralized in the central river basins so the correlation gets weaker: during El Nino (La Nina) events, the reduction (increasing) in rainfall at north is counter balanced by the enhancement (reduction) of rainfall at south associated with cold fronts.

  12. Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation.

    PubMed

    Ochoa, Luz Eneida; Pereira, Luiz Henrique G; Costa-Silva, Guilherme Jose; Roxo, Fábio F; Batista, Jacqueline S; Formiga, Kyara; Foresti, Fausto; Oliveira, Claudio

    2015-05-01

    Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for F ST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2-2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2-2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin. PMID:26045952

  13. Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation

    PubMed Central

    Ochoa, Luz Eneida; Pereira, Luiz Henrique G; Costa-Silva, Guilherme Jose; Roxo, Fábio F; Batista, Jacqueline S; Formiga, Kyara; Foresti, Fausto; Oliveira, Claudio

    2015-01-01

    Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for FST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2–2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2–2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin. PMID:26045952

  14. Influence of salinity and temperature on the oxygen consumption in young juveniles of the Indian prawn Penaeus indicus

    Microsoft Academic Search

    M. N. Kutty; G. Murugapoopathy; T. S. Krishnan

    1971-01-01

    Routine oxygen consumption of very young juveniles (0.1 g) of Penaeus indicusH. Milne Edwards was significantly influenced by ambient temperature and weight of the animal, but not by ambient salinity, when tested at salinities (7, 21, and 35‰) to which they had been long-term (over 10 days) acclimated. Standard oxygen consumption of young juvenile prawns (1 to 3 g), subjected

  15. Preparation of Two Recombinant Crustacean Hyperglycemic Hormones from the Giant Freshwater Prawn, Macrobrachium rosenbergii, and Their Hyperglycemic Activities

    Microsoft Academic Search

    Tsuyoshi Ohira; Naoaki Tsutsui; Hiromichi Nagasawa; Marcy N. Wilder

    2006-01-01

    Crustacean hyperglycemic hormone (CHH) is released from the X-organ\\/sinus gland complex located in the eyestalks, and regulates glucose levels in the hemolymph. In the giant freshwater prawn ( Macrobrachium rosenbergii ), two cDNAs encoding different CHH molecules were previously cloned by other workers. One of these (Mar-CHH-2) was expressed only in the eyestalks, whereas the other (Mar-CHH-L) was expressed in

  16. Current status of freshwater prawn culture in Vietnam and the development and transfer of seed production technology

    Microsoft Academic Search

    Nguyen Thanh Phuong; Tran Ngoc Hai; Tran Thi Thanh Hien; Tran Van Bui; Do Thi Thanh Huong; Vu Nam Son; Yoshinori Morooka; Yutaka Fukuda; Marcy N. Wilder

    2006-01-01

    In Vietnam, the giant freshwater prawn Macrobrachium rosenbergii is becoming an increasingly important targeted species, as its culture, especially in rice fields, is considered to have\\u000a the potential to raise income among improverished farmers. The production of M. rosenbergii based on aquaculture reached over 10 000 tons per year in 2002, having increased from about 2500 tons since the 1990s.

  17. Isolation and characterization of a female-specific DNA marker in the giant freshwater prawn Macrobrachium rosenbergii

    Microsoft Academic Search

    T Ventura; E D Aflalo; S Weil; K Kashkush; A Sagi

    2011-01-01

    In this study, a female-specific DNA marker in the freshwater prawn Macrobrachium rosenbergii was identified through amplified fragment length polymorphism (AFLP). The AFLP-derived sequence-characterized amplified region (SCAR) marker was tested in over 200 individuals, giving reproducible sex identification. Further molecular characterization of the sex-marker's genomic region (?3 kb long) revealed the presence of tandem and inverted repeats. The ?3-kb sequence

  18. Effects of Water-Borne Copper on Digestive and Metabolic Enzymes of the Giant Freshwater Prawn Macrobrachium rosenbergii

    Microsoft Academic Search

    Na Li; Yunlong Zhao; Jian Yang

    2008-01-01

    The aim of the present study was to evaluate the potential utility of enzyme parameters as indicators of water-borne copper\\u000a (Cu2+) contamination in the giant freshwater prawn Macrobrachium rosenbergii. Activities of the digestive enzymes of tryptase, pepsin, cellulase, amylase, and metabolic enzymes of alkaline phosphatase\\u000a (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and glutathione-S-transferase (GST) were measured in the hepatopancreas

  19. Modelling sustainable international tourism demand to the Brazilian Amazon

    Microsoft Academic Search

    J. A. Divino; M. J. McAleer

    2008-01-01

    The Amazon rainforest is one of the world’s greatest natural wonders and holds great importance and significance for the world’s environmental balance. Around 60% of the Amazon rainforest is located in the Brazilian territory. The two biggest states of the Amazon region are Amazonas (the upper Amazon) and Pará (the lower Amazon), which together account for around 73% of the

  20. Identification and Characterization of Differentially Expressed Transcripts in the Gills of Freshwater Prawn (Macrobrachium rosenbergii) under Salt Stress

    PubMed Central

    Barman, Hirak Kumar; Patra, Swagat Kumar; Das, Varsha; Mohapatra, Shibani Dutta; Jayasankar, Pallipuram; Mohapatra, Chinmayee; Mohanta, Ramya; Panda, Rudra Prasanna; Rath, Surya Narayan

    2012-01-01

    The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important species. It is a euryhaline shrimp, surviving in wide-range salinity conditions. A change in gene expression has been suggested as an important component for stress management. To better understand the osmoregulatory mechanisms mediated by the gill, a subtractive and suppressive hybridization (SSH) tool was used to identify expressed transcripts linked to adaptations in saline water. A total of 117 transcripts represented potentially expressed under salinity conditions. BLAST analysis identified 22% as known genes, 9% as uncharacterized showing homologous to unannotated ESTs, and 69% as unknown sequences. All the identified known genes representing broad spectrum of biological pathways were particularly linked to stress tolerance including salinity tolerance. Expression analysis of 10 known genes and 7 unknown/uncharacterized genes suggested their upregulation in the gills of prawn exposed to saline water as compared to control indicating that these are likely to be associated with salinity acclimation. Rapid amplification of cDNA ends (RACE) was used for obtaining full-length cDNA of MRSW-40 clone that was highly upregulated during salt exposure. The sequenced ESTs presented here will have potential implications for future understanding about salinity acclimation and/or tolerance of the prawn. PMID:22619594

  1. Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales.

    PubMed

    Stickler, Claudia M; Coe, Michael T; Costa, Marcos H; Nepstad, Daniel C; McGrath, David G; Dias, Livia C P; Rodrigues, Hermann O; Soares-Filho, Britaldo S

    2013-06-01

    Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations' energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local "direct" effects (through changes in ET within the watershed) and the potential regional "indirect" effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world's largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4-8% and 10-12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6-36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry's own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests. PMID:23671098

  2. Proteomic analysis of differentially expressed protein in hemocytes of wild giant freshwater prawn Macrobrachium rosenbergii infected with infectious hypodermal and hematopoietic necrosis virus (IHHNV)

    PubMed Central

    Alinejad, T.; Bin, Kwong Q.; Vejayan, J.; Othman, R.Y.; Bhassu, S.

    2015-01-01

    Epizootic diseases cause huge mortality and economical loses at post larvae stages in freshwater prawn aquaculture industry. These prawns seem less susceptible to viral diseases except for infectious hypodermal and hematopoietic necrosis virus (IHHNV). During viral infection in prawns, hemocytes are the primary organ that shows immunological response within the early stages of infection. We applied proteomic approaches to understand differential expression of the proteins in hemocytes during the viral disease outbreak. To aid the goal, we collected Macrobrachium rosenbergii broodstocks from the local grow out hatchery which reported the first incidence of IHHNV viral outbreak during larvae stage. Primarily, application of the OIE primer targeting 389 bp fragments of IHHNV virus was used in identification of the infected and non-infected samples of the prawn breeding line. Analysis of two-dimensional gel electrophoresis showed specific down-regulation of Arginine kinase and Sarcoplasmic calcium-binding protein and up/down-regulation of Prophenoloxidase1 and hemocyanin isoforms. These proteins were validated using semi quantitative RT-PCR and gene transcripts at mRNA level. These identified proteins can be used as biomarkers, providing a powerful approach to better understanding of the immunity pathway of viral disease with applications in analytic and observational epidemiology diagnosis. Proteomic profiling allows deep insight into the pathogenesis of IHHNV molecular regulation and mechanism of hemocyte in freshwater prawns. PMID:26106581

  3. Proteomic analysis of differentially expressed protein in hemocytes of wild giant freshwater prawn Macrobrachium rosenbergii infected with infectious hypodermal and hematopoietic necrosis virus (IHHNV).

    PubMed

    Alinejad, T; Bin, Kwong Q; Vejayan, J; Othman, R Y; Bhassu, S

    2015-09-01

    Epizootic diseases cause huge mortality and economical loses at post larvae stages in freshwater prawn aquaculture industry. These prawns seem less susceptible to viral diseases except for infectious hypodermal and hematopoietic necrosis virus (IHHNV). During viral infection in prawns, hemocytes are the primary organ that shows immunological response within the early stages of infection. We applied proteomic approaches to understand differential expression of the proteins in hemocytes during the viral disease outbreak. To aid the goal, we collected Macrobrachium rosenbergii broodstocks from the local grow out hatchery which reported the first incidence of IHHNV viral outbreak during larvae stage. Primarily, application of the OIE primer targeting 389 bp fragments of IHHNV virus was used in identification of the infected and non-infected samples of the prawn breeding line. Analysis of two-dimensional gel electrophoresis showed specific down-regulation of Arginine kinase and Sarcoplasmic calcium-binding protein and up/down-regulation of Prophenoloxidase1 and hemocyanin isoforms. These proteins were validated using semi quantitative RT-PCR and gene transcripts at mRNA level. These identified proteins can be used as biomarkers, providing a powerful approach to better understanding of the immunity pathway of viral disease with applications in analytic and observational epidemiology diagnosis. Proteomic profiling allows deep insight into the pathogenesis of IHHNV molecular regulation and mechanism of hemocyte in freshwater prawns. PMID:26106581

  4. Regionalization of Methane Emissions in the Amazon Basin with Multi-temporal Microwave Remote Sensing

    NASA Astrophysics Data System (ADS)

    Melack, J. M.; Hess, L. L.; Forsberg, B. R.; Hamilton, S. K.; Novo, E. M.

    2002-12-01

    Remote sensing of the Amazon basin with passive and active microwave techniques were applied to determine the temporally varying extent of inundation and associated vegetation, and used in conjunction with field measurements to calculate regional rates of methane emission from wetlands to the atmosphere. Monthly inundation areas were derived from analysis of the 37-GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer (1979 -87) for the mainstem Amazon floodplain in Brazil, the Llanos de Moxos (Beni and Mamore rivers) in Bolivia, the Bananal Island (Araguaia River) and Roraima savannas. Data from the Japanese Earth Resources Satellite-1, L-band synthetic aperture radar were used to determine inundation and wetland vegetation for Amazon basin less than 500 m above sea level at high water (May-June 1996) and low water (October 1995). Although all the measurements of methane emission from aquatic habitats have been performed in the deeply inundated, central basin in open water, flooded forests or floating macrophytes, our basin-wide remote sensing has revealed large areas of seasonally flooded savannas. Therefore, improvements in basin-wide estimates of methane emission will require field studies in wetlands such as those in Bolivia, Roraima and the Bananal.

  5. Rare earth elements in river waters

    NASA Technical Reports Server (NTRS)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-01-01

    To characterize the input to the oceans of rare earth elements (REE) in the dissolved and the suspended loads of rivers, the REE concentrations were measured in samples of Amazon, Indus, Mississippi, Murray-Darling, and Ohio rivers and in samples of smaller rivers that had more distinct drainage basin lithology and water chemistry. It was found that, in the suspended loads of small rivers, the REE pattern was dependent on drainage basin geology, whereas the suspended loads in major rivers had relatively uniform REE patterns and were heavy-REE depleted relative to the North American Shale composite (NASC). The dissolved loads in the five major rivers had marked relative heavy-REE enrichments, relative to the NASC and the suspended material, with the (La/Yb)N ratio of about 0.4 (as compared with the ratio of about 1.9 in suspended loads).

  6. Sternopygus branco: A New Species of Neotropical Electric Fish (Gymnotiformes: Sternopygidae) from the Lowland Amazon Basin, with Descriptions of Osteology, Ecology, and Electric Organ Discharges

    Microsoft Academic Search

    William G. R. Crampton; Kevin G. Hulen; James S. Albert; J. W. Armbruster

    2004-01-01

    Sternopygus branco n. sp. is described from the Amazon River between its conflu- ences with the Rios Japuraand Negro, and from the lower 100 km of the Rio Negro. This species is described using features of external morphology, meristics, pigmen- tation, osteology, and electric organ discharges (EODs). The new species is diag- nosed by a very low EOD repetition rate

  7. BanAI a new isoschizomer of the type II restriction endonuclease HaeIII discovered in a Bacillus anthracis isolate from Amazon Basin

    Microsoft Academic Search

    Jocelei M Chies; Ana C de O. Dias; Helio M. M Maia; Spartaco Astolfi-Filho

    2002-01-01

    Bacillus anthracis was isolated and identified from a bacterial collection of samples from the Amazon river bank. Type II restriction endonuclease activity was detected in this prokaryote, the enzyme was purified, the molecular mass of the native protein estimated by gel filtration, and optima pH, temperature and salt requirements were determined. Quality control assays showed complete absence of ‘non-specific nucleases’.

  8. A new species of freshwater crab of the genus Microthelphusa Pretzmann, 1968 (Crustacea: Brachyura: Pseudothelphusidae) from the Amazon region of Guyana.

    PubMed

    Pedraza, Manuel; Tavares, Marcos

    2014-01-01

    A new species of freshwater crab, Microthelphusa furcifer, is described and illustrated from the Potaro-Siparuni Kuribrong River in the Guyana Shield (Amazon region of Guyana). The new species can be easily separated from its congeners by the morphology of the first gonopod. The first gonopod of Microthelphusa meansi Cumberlidge, 2007, is illustrated to clarify some aspects of its morphology.  PMID:25112338

  9. Immunological characterization of cortical rod proteins of kuruma prawn, Marsupenaeus japonicus.

    PubMed

    Yamano, Keisuke; Seto, Hisatake; Qiu, Gao-Feng; Unuma, Tatsuya

    2003-10-01

    The penaeid shrimp develops cortical rods (CRs) in the oocyte after completing yolk accumulation during ovarian maturation. In this study, CRs from the mature ovary of the kuruma prawn (Marsupenaeus japonicus) were isolated and their proteins were characterized. Under reducing conditions of SDS-PAGE, the CR demonstrated five major bands of approximately 210, 150, 140, 130 and 30 kDa. Of 32 clones of monoclonal antibodies raised against the CR proteins, 21 were found to be immunoreactive by Western blotting, demonstrating 150, 140 and 130 kDa proteins simultaneously. This result suggested that the proteins were post-translational or post-transcriptional products from the same gene, or that they originated from the same gene family. CRs were identified by immunohistochemical analysis by 31 clones of monoclonal antibodies in paraffin sections and by 26 clones in cryostatic ones. Most of the antibodies also stained the yolk in both developing and mature oocytes, suggesting that CR proteins accumulated in developing oocytes, then assembled to form the CR structure. PMID:14511755

  10. Monodon baculovirus (MBV) infects the freshwater prawn Macrobrachium rosenbergii cultivated in Thailand.

    PubMed

    Gangnonngiw, Warachin; Laisutisan, Kesinee; Sriurairatana, Siriporn; Senapin, Saengchan; Chuchird, Niti; Limsuwan, Chalor; Chaivisuthangkura, Parin; Flegel, Timothy W

    2010-03-01

    Field specimens of post-larvae of the giant freshwater prawn (Macrobrachium rosenbergii) from Thailand showed hepatopancreatic tubule epithelial cells that contained central, eosinophilic inclusions within enlarged nuclei and marginated chromatin. These inclusions resembled those produced by some baculoviruses prior to formation of occlusion bodies that enclose virions in a polyhedrin protein matrix. By electron microscopy, the intranuclear inclusions contained bacilliform, enveloped virions (approximately 327+/-29nmx87+/-12nm) with evenly dense, linear nucleocapsids surrounded by trilaminar envelopes with lateral pockets containing nucleoproteinic filaments. In some cases, these were accompanied by moderately electron dense, spherical particles of approximately 20nm diameter resembling polyhedrin subunits of occlusion bodies (OB) of a bacilliform virus of the black tiger shrimp Penaeus monodon, previously reported from Thailand and called monodon baculovirus (MBV). It is currently listed by the International Committee on Taxonomy of viruses as Penaeus monodon nucleopolyhedrovirus (PemoNPV). Two polymerase chain reaction (PCR) assays for MBV gave positive results with DNA extracts prepared from M. rosenbergii samples using the hot phenol technique. One of these assays targeted the polyhedrin gene of MBV to which the resulting amplicon showed 100% sequence identity. Presence of the Penaeus monodon virus polyhedrin gene was confirmed by in situ hybridization assays and by positive immunohistochemical reactions in one sample batch. The data revealed that MBV can be found but may rarely produce polyhedrin occlusion bodies in M. rosenbergii. PMID:19963025

  11. Pre-Columbian Urbanism, Anthropogenic Landscapes, and the Future of the Amazon

    NASA Astrophysics Data System (ADS)

    Heckenberger, Michael J.; Russell, J. Christian; Fausto, Carlos; Toney, Joshua R.; Schmidt, Morgan J.; Pereira, Edithe; Franchetto, Bruna; Kuikuro, Afukaka

    2008-08-01

    The archaeology of pre-Columbian polities in the Amazon River basin forces a reconsideration of early urbanism and long-term change in tropical forest landscapes. We describe settlement and land-use patterns of complex societies on the eve of European contact (after 1492) in the Upper Xingu region of the Brazilian Amazon. These societies were organized in articulated clusters, representing small independent polities, within a regional peer polity. These patterns constitute a “galactic” form of prehistoric urbanism, sharing features with small-scale urban polities in other areas. Understanding long-term change in coupled human-environment systems relating to these societies has implications for conservation and sustainable development, notably to control ecological degradation and maintain regional biodiversity.

  12. Using remote sensing for validation of a large scale hydrologic and hydrodynamic model in the Amazon

    NASA Astrophysics Data System (ADS)

    Paiva, R. C.; Bonnet, M.; Buarque, D. C.; Collischonn, W.; Frappart, F.; Mendes, C. B.

    2011-12-01

    We present the validation of the large-scale, catchment-based hydrological MGB-IPH model in the Amazon River basin. In this model, physically-based equations are used to simulate the hydrological processes, such as the Penman Monteith method to estimate evapotranspiration, or the Moore and Clarke infiltration model. A new feature recently introduced in the model is a 1D hydrodynamic module for river routing. It uses the full Saint-Venant equations and a simple floodplain storage model. River and floodplain geometry parameters are extracted from SRTM DEM using specially developed GIS algorithms that provide catchment discretization, estimation of river cross-sections geometry and water storage volume variations in the floodplains. The model was forced using satellite-derived daily rainfall TRMM 3B42, calibrated against discharge data and first validated using daily discharges and water levels from 111 and 69 stream gauges, respectively. Then, we performed a validation against remote sensing derived hydrological products, including (i) monthly Terrestrial Water Storage (TWS) anomalies derived from GRACE, (ii) river water levels derived from ENVISAT satellite altimetry data (212 virtual stations from Santos da Silva et al., 2010) and (iii) a multi-satellite monthly global inundation extent dataset at ~25 x 25 km spatial resolution (Papa et al., 2010). Validation against river discharges shows good performance of the MGB-IPH model. For 70% of the stream gauges, the Nash and Suttcliffe efficiency index (ENS) is higher than 0.6 and at Óbidos, close to Amazon river outlet, ENS equals 0.9 and the model bias equals,-4.6%. Largest errors are located in drainage areas outside Brazil and we speculate that it is due to the poor quality of rainfall datasets in these areas poorly monitored and/or mountainous. Validation against water levels shows that model is performing well in the major tributaries. For 60% of virtual stations, ENS is higher than 0.6. But, similarly, largest errors are also located in drainage areas outside Brazil, mostly Japurá River, and in the lower Amazon River. In the latter, correlation with observations is high but the model underestimates the amplitude of water levels. We also found a large bias between model and ENVISAT water levels, ranging from -3 to -15 m. The model provided TWS in good accordance with GRACE estimates. ENS values for TWS over the whole Amazon equals 0.93. We also analyzed results in 21 sub-regions of 4 x 4°. ENS is smaller than 0.8 only in 5 areas, and these are found mostly in the northwest part of the Amazon, possibly due to same errors reported in discharge results. Flood extent validation is under development, but a previous analysis in Brazilian part of Solimões River basin suggests a good model performance. The authors are grateful for the financial and operational support from the brazilian agencies FINEP, CNPq and ANA and from the french observatories HYBAM and SOERE RBV.

  13. Strontium and its isotopes in Canadian rivers: Fluxes and global implications

    Microsoft Academic Search

    Moire A. Wadleigh; Ján Veizer; Christopher Brooks

    1985-01-01

    Systematic sampling of the 39 largest Canadian rivers shows that the weighted average 87 Sr \\/ 86 Sr ratio in the dissolved load is 0.7111, similar to previous measurements on such large rivers as the Amazon and Mississippi. Consequently, we believe that the above estimate is likely representative of the global average. This imposes a limit of 6.5 × 10

  14. Journey to Planet Earth: Rivers of Destiny. The Public Television Series. [Videotape].

    ERIC Educational Resources Information Center

    1999

    This video program focuses on four rivers: the Mississippi, the Amazon, the Jordan, and the Mekong. Each locale serves as an example of what can happen when human beings tamper with the natural system of a river. Without thoughtful planning, the consequences can be disastrous,, but when communities work together, a balance can be achieved between…

  15. Amazon Rain Forest Classification Using J-ERS-1 SAR Data

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Kramer, C.; Alves, M.; Chapman, B.

    1994-01-01

    The Amazon rain forest is a region of the earth that is undergoing rapid change. Man-made disturbance, such as clear cutting for agriculture or mining, is altering the rain forest ecosystem. For many parts of the rain forest, seasonal changes from the wet to the dry season are also significant. Changes in the seasonal cycle of flooding and draining can cause significant alterations in the forest ecosystem.Because much of the Amazon basin is regularly covered by thick clouds, optical and infrared coverage from the LANDSAT and SPOT satellites is sporadic. Imaging radar offers a much better potential for regular monitoring of changes in this region. In particular, the J-ERS-1 satellite carries an L-band HH SAR system, which via an on-board tape recorder, can collect data from almost anywhere on the globe at any time of year.In this paper, we show how J-ERS-1 radar images can be used to accurately classify different forest types (i.e., forest, hill forest, flooded forest), disturbed areas such as clear cuts and urban areas, and river courses in the Amazon basin. J-ERS-1 data has also shown significant differences between the dry and wet season, indicating a strong potential for monitoring seasonal change. The algorithm used to classify J-ERS-1 data is a standard maximum-likelihood classifier, using the radar image local mean and standard deviation of texture as input. Rivers and clear cuts are detected using edge detection and region-growing algorithms. Since this classifier is intended to operate successfully on data taken over the entire Amazon, several options are available to enable the user to modify the algorithm to suit a particular image.

  16. Major changes in glacial and Holocene terrestrial temperatures and sources of organic carbon recorded in the Amazon fan by tetraether lipids

    NASA Astrophysics Data System (ADS)

    Bendle, James A.; Weijers, Johan W. H.; Maslin, Mark A.; Sinninghe Damsté, Jaap S.; Schouten, Stefan; Hopmans, Ellen C.; Boot, Christopher S.; Pancost, Richard D.

    2010-12-01

    The Amazon basin is a major component of the global carbon and hydrological cycles, a significant natural source of methane, and home to remarkable biodiversity and endemism. Reconstructing past climate changes in the Amazon basin is important for a better understanding of the effect of such changes on these critical functions of the basin. Using a novel biomarker proxy, based on the membrane lipids of soil bacteria with a new regional calibration, we present a reconstruction of changes in mean annual air temperatures for the Amazon catchment during the last 37 kyr B.P. Biomarkers were extracted from Ocean Drilling Program sediment core ODP942 recovered from the Amazon fan. The Amazon fan is a major depository for terrestrial sediments, with the advantage that the terrestrial material captured reflects a regional integration of the whole river catchment. The reconstructed tropical Amazonian temperatures were ˜5°C cooler at the Last Glacial Maximum (˜21°C) compared to modern values (˜26°C). This is in agreement with previous estimates of tropical continental temperatures in the tropical Amazon basin and tropical Africa during the Last Glacial Maximum. Moreover, we also illustrate how the soil bacterial membrane lipid record reveals major changes in basin dynamics and sediment provenance during the glacial-Holocene transition, impacting the biomarker reconstructions from ˜11 kyr onward.

  17. Toxic impact of aldrin on acid and alkaline phosphatase activity of penaeid prawn, Metapenaeus monoceros: In vitro study

    SciTech Connect

    Reddy, M.S.; Jayaprada, P.; Rao, K.V.R. (Sri Venkateswara Univ. Post Graduate Center, Kavali (India))

    1991-03-01

    The increasing contamination of the aquatic environment by the indiscriminate and widespread use of different kinds of pesticides is a serious problem for environmental biologists. Organochlorine insecticides are more hazardous since they are not only more toxic but also leave residues in nature. The deleterious effects of aldrin on several crustaceans have been studied. But studies concerning the impact of aldrin on biochemical aspects of crustaceans are very much limited. The present study is aimed at probing the in vitro effects of aldrin on the acid and alkaline phosphatase activity levels in selected tissues of penaeid prawn, Metapenaeus monoceros (Fabricius).

  18. RESEARCH PAPER Mating Preferences of the Gynogenetic Amazon Molly Differ

    E-print Network

    Gabor, Caitlin - Department of Biology, Texas State University

    Amazon molly (Poecilia formosa) is a species of hybrid origins that are sympatric with one of the two parent species that provide sperm for reproduction, P. latipinna or P. mexicana. Amazons should preference across the different models. In contrast, Amazons from a popu- lation sympatric with P. mexicana

  19. Please consider the environment before printing Amazon logging industry declines

    E-print Network

    Please consider the environment before printing Amazon logging industry declines mongabay.com June on the Amazon logging industry in Brazil, reports a major new assessment conducted by Imazon and the Brazilian Grosso (33 percent) and Rondonia (15 percent). 9/13/2010 Amazon logging industry declines - Print

  20. Rapid neodymium release to marine waters from lithogenic sediments in the Amazon estuary.

    PubMed

    Rousseau, Tristan C C; Sonke, Jeroen E; Chmeleff, Jérôme; van Beek, Pieter; Souhaut, Marc; Boaventura, Geraldo; Seyler, Patrick; Jeandel, Catherine

    2015-01-01

    Rare earth element (REE) concentrations and neodymium isotopic composition (?Nd) are tracers for ocean circulation and biogeochemistry. Although models suggest that REE release from lithogenic sediment in river discharge may dominate all other REE inputs to the oceans, the occurrence, mechanisms and magnitude of such a source are still debated. Here we present the first simultaneous observations of dissolved (<0.45??m), colloidal and particulate REE and ?Nd in the Amazon estuary. A sharp drop in dissolved REE in the low-salinity zone is driven by coagulation of colloidal matter. At mid-salinities, total dissolved REE levels slightly increase, while ?Nd values are shifted from the dissolved Nd river endmember (-8.9) to values typical of river suspended matter (-10.6). Combining a Nd isotope mass balance with apparent radium isotope ages of estuarine waters suggests a rapid (3 weeks) and globally significant Nd release by dissolution of lithogenic suspended sediments. PMID:26158849

  1. Delineation of inundated area and vegetation along the Amazon floodplain with the SIR-C synthetic aperture radar

    Microsoft Academic Search

    Laura L. Hess; John M. Melack; Solange Filoso; Yong Wang

    1995-01-01

    Floodplain inundation and vegetation along the Negro and Amazon rivers near Manaus, Brazil were accurately delineated using multi-frequency, polarimetric synthetic aperture radar (SAR) data from the April and October 1994 SIR-C missions. A decision-tree model was used to formulate rules for a supervised classification into five categories: water, clearing (pasture), aquatic macrophyte (floating meadow), nonflooded forest, and flooded forest. Classified

  2. Modelling conservation in the Amazon basin

    NASA Astrophysics Data System (ADS)

    Soares-Filho, Britaldo Silveira; Nepstad, Daniel Curtis; Curran, Lisa M.; Cerqueira, Gustavo Coutinho; Garcia, Ricardo Alexandrino; Ramos, Claudia Azevedo; Voll, Eliane; McDonald, Alice; Lefebvre, Paul; Schlesinger, Peter

    2006-03-01

    Expansion of the cattle and soy industries in the Amazon basin has increased deforestation rates and will soon push all-weather highways into the region's core. In the face of this growing pressure, a comprehensive conservation strategy for the Amazon basin should protect its watersheds, the full range of species and ecosystem diversity, and the stability of regional climates. Here we report that protected areas in the Amazon basin-the central feature of prevailing conservation approaches-are an important but insufficient component of this strategy, based on policy-sensitive simulations of future deforestation. By 2050, current trends in agricultural expansion will eliminate a total of 40% of Amazon forests, including at least two-thirds of the forest cover of six major watersheds and 12 ecoregions, releasing 32 +/- 8Pg of carbon to the atmosphere. One-quarter of the 382 mammalian species examined will lose more than 40% of the forest within their Amazon ranges. Although an expanded and enforced network of protected areas could avoid as much as one-third of this projected forest loss, conservation on private lands is also essential. Expanding market pressures for sound land management and prevention of forest clearing on lands unsuitable for agriculture are critical ingredients of a strategy for comprehensive conservation.

  3. Forecasting Total Water Storage Changes in the Amazon basin using Atlantic and Pacific Sea Surface Temperatures

    NASA Astrophysics Data System (ADS)

    De Linage, C.; Famiglietti, J. S.; Randerson, J. T.

    2013-12-01

    Floods and droughts frequently affect the Amazon River basin, impacting the transportation, river navigation, agriculture, economy and the carbon balance and biodiversity of several South American countries. The present study aims to find the main variables controlling the natural interannual variability of terrestrial water storage in the Amazon region and to propose a modeling framework for flood and drought forecasting. We propose three simple empirical models using a linear combination of lagged spatial averages of central Pacific (Niño 4 index) and tropical North Atlantic (TNAI index) sea surface temperatures (SST) to predict a decade-long record of 3°, monthly terrestrial water storage anomalies (TWSA) observed by the Gravity Recovery And Climate Experiment (GRACE) mission. In addition to a SST forcing term, the models included a relaxation term to simulate the memory of water storage anomalies in response to external variability in forcing. Model parameters were spatially-variable and individually optimized for each 3° grid cell. We also investigated the evolution of the predictive capability of our models with increasing minimum lead times for TWSA forecasts. TNAI was the primary external forcing for the central and western regions of the southern Amazon (35% of variance explained with a 3-month forecast), whereas Niño 4 was dominant in the northeastern part of the basin (61% of variance explained with a 3-month forecast). Forcing the model with a combination of the two indices improved the fit significantly (p<0.05) for at least 64% of the grid cells, compared to models forced solely with Niño 4 or TNAI. The combined model was able to explain 43% of the variance in the Amazon basin as a whole with a 3-month lead time. While 66% of the observed variance was explained in the northeastern Amazon, only 39% of the variance was captured by the combined model in the central and western regions, suggesting that other, more local, forcing sources were important in these regions. The predictive capability of the combined model was monotonically degraded with increasing lead times. Degradation was smaller in the northeastern Amazon (where 49% of the variance was explained using a 8-month lead time versus 69% for a 1 month lead time) compared to the western and central regions of southern Amazon (where 22% of the variance was explained at 8 months versus 43% at 1 month). Our model may provide early warning information about flooding in the northeastern region of the Amazon basin, where floodplain areas are extensive and the sensitivity of floods to external SST forcing was shown to be high. This work also strengthens our understanding of the mechanisms regulating interannual variability in Amazon fires, as TWSA deficits may subsequently lead to atmospheric water vapor deficits and reduced cloudiness via water-limited evapotranspiration. Finally, this work helps to bridge the gap between the current GRACE mission and the follow-on gravity mission.

  4. The recent extreme hydrological events in the Western Amazon Basin: The role of the Pacific and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Espinoza, J.; Ronchail, J.; Guyot, J.; Santini, W.; Lavado, W.; Ore-Hybam Observatory

    2013-05-01

    The Peruvian Amazonas River, the main western tributary of the Amazon basin, has a huge drainage (750 000 km2, 50% of which lies in the Andes) and a mean discharge estimated in 32 000 m3/s, which correspond to 15% of the Amazon discharge at the estuary. Recently, in a context of significant discharge diminution during the low-water season (1970-2012), severe hydrological events, as intense droughts and floods, have been reported in the Peruvian Amazonas River. As they have not been always observed in other regions of the Amazon basin and because they have strong impacts on vulnerable riverside residents, we shall focus on the origin and the predictability of the western Amazon extremes, providing a review of the main findings about the climate features during recent extreme hydrological events in western Amazon. While the lowest discharge value was observed in September 2010 (8 300 m3/s) at the hydrological Tamshiyacu station (near to Iquitos city), a rapid transition toward a high discharge was noticed in April 2011 (45 000 m3/s). Finally, in April 2012, during the on going high waters period, the Amazonas River is experimenting its historical highest discharge (55 000 m3/s). Our work is based on several datasets including in-situ discharge and rainfall information from ORE-HYBAM observatory. Extreme droughts (1995, 2005 and 2010) are generally associated with positive SST anomalies in the tropical North Atlantic and weak trade winds and water vapor transport toward the western Amazon, which, in association with increased subsidence over central and southern Amazon, explain the lack of rainfall and very low discharge values. But, in 1998, toward the end of the 1997-98 El Niño event, the drought has been more likely related to an anomalous divergence of water vapor in the western Amazon that is characteristic of a warm event in the Pacific. The years with a rapid transition form low waters to very high floods (e.g. September 2010 to April 2011) are characterized by negative SST anomalies in the central equatorial Pacific during austral summer, corresponding to a La Niña mode. As a consequence of atmospheric teleconnections related to La Niña, the monsoon flux is retained over the Amazon and a strong convergence of humidity occurs in the north-western Amazon basin, favouring high rainfall and discharge. These features were also observed during the 2012 austral summer, with a major advection of humidity from the Caribbean Sea. During this event, an anticipated rainfall season also played an important role on the onset of the flood. In conclusion, recent works reveal an influence of the tropical North Atlantic on extreme droughts in the western Amazon, during the austral winter and spring, and a role of SST variability in the central equatorial Pacific to modulate floods intensity during the austral summer season.

  5. Amazon Health / Human Origins Update

    NSDL National Science Digital Library

    This 47-minute radio broadcast discusses a report by biologists that the types of trees in the inner Amazon rainforest are changing. Increasingly, they've found, larger, faster-growing tree species are crowding out smaller slower tree types - even in areas that have not yet been touched by logging or fires. The researchers suggest that increased carbon dioxide levels could be to blame. The second part of the show takes a look at current research into human origins. There is discussion about several recent research projects, including one which discovered six million-year-old fossils that may have come from one of the earliest known human ancestors and a new genetic analysis of mitochondrial DNA that researchers say shows that humans and Neanderthals did not interbreed. The show discusses the fossils of Ardipithecus kadabba; how temperature affects the extraction of DNA from fossils; how 5-7 million years ago the number of great ape species outnumbered that of monkeys; whether human ancestors had greater ability to form speech than Neanderthals; and how the gap in the fossil record of human ancestors is being filled.

  6. The impact of turtle excluder devices and bycatch reduction devices on diverse tropical marine communities in Australia's northern prawn trawl fishery

    Microsoft Academic Search

    David Brewer; Don Heales; David Milton; Quinton Dell; Gary Fry; Bill Venables; Peter Jones

    2006-01-01

    In 2001, paired-trawl comparisons were made during prawn trawl operations to assess the effect of turtle excluder devices and bycatch reduction devices on a range of species groups caught in tropical Australia. This study is one of the first to evaluate the commercial use of these devices in a tropical fishery. Nets with a combination of a turtle excluder device

  7. Neogene-Quaternary sedimentary and paleovegetation history of the eastern Solimões Basin, central Amazon region

    NASA Astrophysics Data System (ADS)

    Nogueira, Afonso César Rodrigues; Silveira, Rosemery; Guimarães, José Tasso Felix

    2013-10-01

    Palynological and stratigraphical analyses were carried out on the outcrops of the Solimões River to present new information about freshwater paleoenvironments of a fluvial-deltaic and meandering river system, evaluate the vegetation changes in the upper Solimões and Içá Formations in the eastern Solimões Basin, and the role of the Purus Arc in the evolution of central Amazon during the upper Neogene. The upper Miocene to Pliocene Solimões Formation is related to a fluvial-deltaic system, with fine-grained sediments of the prodelta-lacustrine environment supplied by meandering distributaries and delta front environment. The lake and distributaries were surrounded by extensive deltaic and floodplains colonized by lowland freshwater forests under wet climate conditions, persisting until the Pliocene. The Içá Formation started to deposit unconformably on the Solimões Formation during the Pleistocene, following the development of extensive meandering channels surrounded by floodplains of an essentially fluvial system linked to development of the present eastward direction of the Amazon River until the Atlantic coast. These floodplains were colonized by few palm species and pteridophytes of lowland freshwater forests during the Pleistocene. Additionally, no algae and fungi were observed, which may be related to drier climate conditions and/or different morphological conditions than the upper Solimões Formation.

  8. Lipid and fatty acid composition of hepatopancreatic brush-border membrane vesicles from the prawn Penaeus japonicus.

    PubMed

    Muriana, F J; Ruíz-Gutiérrez, V; Blaya, J A; Bolufer, J

    1993-05-01

    Brush-border membrane vesicles (BBMV) were isolated from prawn hepatopancreas by a procedure involving Mg2+ preparation. The lipid composition of hepatopancreatic BBMV (hBBMV) was examined by the Iatroscan TLC/FID technique, and the fatty acid profile of total lipids was determined by capillary gas chromatography. hBBMV were characterized by a high content of phospholipids and cholesterol. However, the cholesterol/phospholipid molar ratio is lower in prawn than in vertebrate BBMV, which agrees well with the membrane fluidity of BBMV from different sources. The fatty acid composition of hBBMV was similar to that in marine crustacean oils. The major fatty acids present were palmitic (16:0), palmitoleic (16:1n-7), stearic (18:0), oleic (18:1n-9), and eicosapentaenoic (20:5n-3) acids. The large amount of long-chain polyunsaturated fatty acids seems to be related to a high delta 5-desaturase activity in hBBMV. PMID:8340355

  9. Immune gene discovery by expressed sequence tag (EST) analysis of hemocytes in the ridgetail white prawn Exopalaemon carinicauda

    PubMed Central

    Duan, Yafei; Liu, Ping; Li, Jitao; Li, Jian; Chen, Ping

    2013-01-01

    The ridgetail white prawn Exopalaemon carinicauda is one of the most important commercial species in eastern China. However, little information of immune genes in E. carinicauda has been reported. To identify distinctive genes associated with immunity, an expressed sequence tag (EST) library was constructed from hemocytes of E. carinicauda. A total of 3411 clones were sequenced, yielding 2853 ESTs and the average sequence length is 436 bp. The cluster and assembly analysis yielded 1053 unique sequences including 329 contigs and 724 singletons. Blast analysis identified 593 (56.3%) of the unique sequences as orthologs of genes from other organisms (E-value < 1e-5). Based on the COG and Gene Ontology (GO), 593 unique sequences were classified. Through comparison with previous studies, 153 genes assembled from 367 ESTs have been identified as possibly involved in defense or immune functions. These genes are categorized into seven categories according to their putative functions in shrimp immune system: antimicrobial peptides, prophenoloxidase activating system, antioxidant defense systems, chaperone proteins, clottable proteins, pattern recognition receptors and other immune-related genes. According to EST abundance, the major immune-related genes were thioredoxin (141, 4.94% of all ESTs) and calmodulin (14, 0.49% of all ESTs). The EST sequences of E. carinicauda hemocytes provide important information of the immune system and lay the groundwork for development of molecular markers related to disease resistance in prawn species. PMID:23092732

  10. Molecular cloning and characterisation of peroxinectin, a cell adhesion molecule, from the giant freshwater prawn Macrobrachium rosenbergii.

    PubMed

    Hsu, Pei-I; Liu, Chun-Hung; Tseng, Deng-Yu; Lee, Pai-Po; Cheng, Winton

    2006-07-01

    Expression of peroxinectin cDNA was determined from haemocytes of giant freshwater prawn Macrobrachium rosenbergii using oligonucleotide primers and reverse transcription polymerase chain reaction (RT-PCR) based on the peroxinectin sequence of white shrimp Litopenaeus vannamei, tiger shrimp Penaeus monodon, and freshwater crayfish Pacifastacus leniusculus. The peroxinectin of M. rosenbergii was constitutively expressed. Analysis of the nucleotide sequence revealed that the cDNA clone has an open reading frame of 2,403 bp encoding a protein of 801 amino acids including a 20 amino acid signal peptide. The calculated molecular mass of the mature protein (781 amino acids) was 88.7 kDa with an estimated pI of 6.8. A putative peroxidase domain and a putative integrin-binding motif, KGD (Lys-Gly-Asp) were observed in prawn peroxinectin at the C-terminal. Sequence comparison showed that peroxinectin deduced amino acid of M. rosenbergii had an overall similarity of 62%, 64%, and 66% to that of P. leniusculus, P. monodon, and L. vannamei, respectively. Quantitative real-time PCR analysis showed that peroxinectin transcript in haemocyte of M. rosenbergii decreased significantly after 3, 6 and 12h injection with Lactococcus garvieae. PMID:16377210

  11. Evaluating the Amazon water cycle components using ED model against GRACE

    NASA Astrophysics Data System (ADS)

    Lee, E.; Han, S. C.; Yeo, I. Y.; Longo, M.; Swann, A. L. S.; Knox, R. G.; Briscoe, J.; Moorcroft, P. R.

    2014-12-01

    Changes in the water cycle components of the Amazon and its surrounding regions are a key to assessing regional impacts of climate and land-cover changes, as they may affect rain-fed agriculture and hydroelectric power generation in Brazil. A comprehensive validation of the modeled water budget, therefore, is a necessary part of understanding the region's hydroclimatology. We evaluate the water cycle components from Ecosystem Demography (ED) model both as a stand-alone model and a coupled model to the Brazilian Regional Atmospheric Modeling System (BRAMS). Model results are compared with satellite-driven observations and a flux tower measurement in central Amazon. Our results indicate that the modeled EDBRAMS precipitation over Amazonia replicates the observed patterns of the Tropical Rainfall Measuring Mission (TRMM) from 2001 to 2009. Total Water Storage Change (TWSC) anomalies from the ED model at the Paraná River basin shows a better agreement with the Gravity Recovery And Climate Experiment (GRACE) satellite observation from 2002 to 2008, as compared to the Global Land Data Assimilation System (GLDAS)/NOAH model. The Nash-Sutcliff model efficiency coefficient improved from 0.50 (GLDAS/NOAH vs. GRACE) to 0.65 (ED vs. GRACE). We also evaluate the modeled evapotranspiration (ET) against the flux tower measurement. Our study affirms the capabilities of the ED model in simulating the Amazon hydrological cycle, which helps investigate its sustainable thresholds with various land-cover and climate change scenarios.

  12. Gene expression profile analysis of testis and ovary of oriental river prawn, Macrobrachium nipponense, reveals candidate reproduction-related genes.

    PubMed

    Qiao, H; Xiong, Y W; Jiang, S F; Fu, H T; Sun, S M; Jin, S B; Gong, Y S; Zhang, W Y

    2015-01-01

    This study utilized high-throughput RNA sequencing technology to identify reproduction- and development-related genes of Macrobrachium nipponense by analyzing gene expression profiles of testis and ovary. More than 20 million 1 x 51-bp reads were obtained by Illumina sequencing, generating more than 7.7 and 11.7 million clean reads in the testis and ovary library, respectively. As a result, 10,018 unitags were supposed to be differentially expressed genes (DEGs) between ovary and testis. Compared to the ovary library, 4563 (45.5%) of these DEGs exhibited at least 6-fold upregulated expression, while 5455 (54.5%) DEGs exhibited at least 2-fold downregulated expression in the testis. The Gene Ontology (GO) enrichment analysis showed that 113 GO terms had potential molecular functions in reproduction. The Kyoto Encyclopedia of Genes and Genomes results revealed that the most important pathways may be relevant to reproduction and included 7 pathways. Forty-two genes were identified as reproduction-, development-, and sex-related genes based on GO classification and sequence comparison with other publications, including male reproductive-related LIM protein, spermatogenesis-associated protein, gametocyte-specific factor 1, VASA-like protein, vitellogenin, sex-determining protein fem-1, and other potential candidates. These results will advance research in the field of molecular genetics in M. nipponense and offer a valuable resource for further research related to reproduction in crustaceans. PMID:25867350

  13. Amazon Paleofires Records: Comparison Between Land Use Change and Palaeoclimatic Events

    NASA Astrophysics Data System (ADS)

    Cordeiro, R. C.; Turcq, B.; Moreira, L. S.; Rodrigues, R. D. A.; Simões Filho, F. L.; Martins, G. S.; Santos, A. B.; Barbosa, M.; da Conceição, M. C. G.; Rodrigues, R. D. C.; Evangelista, H.; Moreira-Turcq, P. F.; Penido, Y. P.; Sifeddine, A.; Seoane, J.

    2014-12-01

    Interpreting the geological record of Amazon biomass combustion requires comparing charcoal accumulation rates in various biomes at different time scales. Charcoal accumulation rates, a proxy for palaeofire records, were obtained in sediment cores from Amazon lakes surrounded by several vegetation types and from a reservoir in an intense land use change region. The records presented in this study were obtained in the following areas i) a reservoir in Alta Floresta region (northern Mato Grosso State); ii) Lago do Saci (southern Pará State), a lake close to Alta Floresta and located at the southern border of Pará State; iii) a bog in an ecotone area in the Humaitá region (southern Amazonas State); iv) lakes in lateritic iron crust of the Carajás Hills (southeastern Pará State); v) Lago Comprido, a floodplain lake close to the Amazon River and surrounded by tropical rain forest (Monte Alegre, Pará State; vi) Lagoa da Pata in the Morro dos Seis Lagos alkaline complex (São Gabriel da Cachoeira, Amazonas State) and vii) Lago Caracaranã, a secluded lake in the northern Amazon cerrado (Roraima State). The highest charcoal accumulation rates were observed for modern records related to an intense change in land use at Alta Floresta, which had no precedent during the Holocene history of the Amazon. High charcoal accumulation rates that were observed in the Carajás region during low lake level phases in the Amazon in the mid-Holocene were comparable to those at the onset of the human settlement in Alta Floresta region. An increase in charcoal accumulation rate was observed in the late Holocene when the lake level was high, suggesting an interaction between climates and human presence. Low charcoal accumulation rates are typical of modern high rainfall environments, as observed in Lagoa da Pata where the environment is not susceptible to occurrences of wildfires even during relatively drier climatic phases. Low charcoal accumulation rates also exist in the relatively dry cerrado (savanna type) biome even during relatively dry phases in the Caracaranã region where the savanna-type vegetation biomass is lower and thus generates less charcoal particles than forest ecosystems.

  14. What Drives Deforestation in the Brazilian Amazon?

    Microsoft Academic Search

    Alexander S. P. Pfaff

    1999-01-01

    While previous empirical analysis of deforestation focused on population, this paper builds from a model of land use which suggests many determinants of deforestation in the Brazilian Amazon. I derive a deforestation equation from this model and test a number of those factors using county-level data for the period 1978–1988. The data include a satellite deforestation measure which allows improved

  15. Satellite Monitoring of the Brazilian Amazon

    E-print Network

    : The birth of a deforestation culture Brazilian original vegetation cover (IBGE) #12;Present population of efectivity of deforestation control policies Public awareness of the deforestation in the amazon (www in Conservation Unities and municipalities #12;#12;2004-jun-08 #12;2004-jun-22 #12;#12;IBAMA's field control

  16. A cytosolic glutathione s-transferase, GST-theta from freshwater prawn Macrobrachium rosenbergii: molecular and biochemical properties.

    PubMed

    Arockiaraj, Jesu; Gnanam, Annie J; Palanisamy, Rajesh; Bhatt, Prasanth; Kumaresan, Venkatesh; Chaurasia, Mukesh Kumar; Pasupuleti, Mukesh; Ramaswamy, Harikrishnan; Arasu, Abirami; Sathyamoorthi, Akila

    2014-08-10

    Glutathione S-transferases play an important role in cellular detoxification and may have evolved to protect cells against reactive oxygen metabolites. In this study, we report the molecular characterization of glutathione s-transferase-theta (GST-?) from freshwater prawn Macrobrachium rosenbergii. A full length cDNA of GSTT (1417 base pairs) was isolated and characterized bioinformatically. Exposure to virus (white spot syndrome baculovirus or M. rosenbergii nodovirus), bacteria (Aeromonas hydrophila or Vibrio harveyi) or heavy metals (cadmium or lead) significantly increased the expression of GSTT (P<0.05) in hepatopancreas. Recombinant GST-? with monochlorobimane substrate had an optimum activity at pH7.5 and 35 °C. Furthermore recombinant GST-? activity was abolished by the denaturants triton X-100, Gua-HCl, Gua-thiocyanate, SDS and urea in a dose-dependent manner. Overall, the results suggest a potential role for M. rosenbergii GST-? in detoxification and possibly conferring immune protection. PMID:24879918

  17. Isolation of a bacterium resembling Pirellula species from primary tissue culture of the giant tiger prawn (Penaeus monodon).

    PubMed Central

    Fuerst, J A; Sambhi, S K; Paynter, J L; Hawkins, J A; Atherton, J G

    1991-01-01

    During attempts to establish tissue cultures from hepatopancreas, heart, and hemolymph of the giant tiger prawn (Penaeus monodon), using a medium including penicillin, streptomycin, and amphotericin B, bacterial contamination in the form of a sheet of growth attached to the tissue culture vessel was a persistent problem. Contaminant bacteria were teardrop-shaped cells arranged in rosettes, and electron microscopy revealed buds, crateriform structures, and the absence of a peptidoglycan layer in the cell wall, features characteristic of bacteria in the Planctomyces-Pirellula group, a phylogenetically distinct group of eubacteria. Two strains of contaminant bacteria were isolated in pure culture. Both exhibited morphology and antibiotic resistance consistent with their membership in the Planctomyces-Pirellula group (order Planctomycetales) of eubacteria. Tissue culture media for marine invertebrates may select for such bacteria if high concentrations of cell wall synthesis-inhibiting antibiotics are included. Images PMID:1781677

  18. Comparison of spaceborne measurements of sea surface salinity and colored detrital matter in the Amazon plume

    NASA Astrophysics Data System (ADS)

    Fournier, S.; Chapron, B.; Salisbury, J.; Vandemark, D.; Reul, N.

    2015-05-01

    Large rivers are key hydrologic components in oceanography, particularly regarding air-sea and land-sea exchanges and biogeochemistry. We enter now in a new era of Sea Surface Salinity (SSS) observing system from Space with the recent launches of the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius/Sac-D missions. With these new sensors, we are now in an excellent position to revisit SSS and ocean color investigations in the tropical northwest Atlantic using multiyear remote sensing time series and concurrent in situ observations. The Amazon is the world's largest river in terms of discharge. In its plume, SSS and upper water column optical properties such as the absorption coefficient of colored detrital matter (acdm) are strongly negatively correlated (<-0.7). Local quasi-linear relationships between SSS and acdm are derived for these plume waters over the period of 2010-2013 using new spaceborne SSS and ocean color measurements. Results allow unprecedented spatial and temporal resolution of this coupling. These relationships are then used to estimate SSS in the Amazon plume based on ocean color satellite data. This new product is validated against SMOS and in situ data and compared with previously developed SSS retrieval models. We demonstrate the potential to estimate tropical Atlantic SSS for the extended period from 1998 to 2010, prior to spaceborne SSS data collection.

  19. Comparison of Late Quaternary Climate Development Between the Niger Catchment Area and the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Zabel, M.; Ettwein, V.; Maslin, M.; Schneider, R. R.

    2003-04-01

    The inorganic terrigenous fraction of marine sediments offers a great number of different and well established proxy parameters to investigate the development of continental climate. In this study we present high resolution records of terrigenous source elements from the Niger River and the Amazon River fans. Sediment cores are well dated by radiocarbon measurements. Elemental records from both regions reveal strong evidence for rapid continental climate change over the last 18.000 years, especially during last deglaciation. While major changes obviously occure nearly simultaneously, the timing of shorter events is clearly offset between the two regions. In addition, significant differences can be recorded for the development of the sedimentary terrigenous composition during the Late Holocene. While element ratios indicates increasing arid conditions in catchment area of the Niger since the end of the last African Humid Period at about 5.5 kyr ago, in consistency with other studies increasing humid conditions prevail in the Amazon Basin during the Holocene. This opposing climate development could be caused by the discussed E-W SST contrasts due to variations in the thermohaline circulation within the tropical Atlantic. However, in order to support our findings in marine sediments and because we know that the terrigenous fraction in marine sediments contains to a certain degree a filtered climatic information due to Land-ocean transport and depositinal processes, we try to verify information from the marine records by additional information from the adjacent region like on sea and lake level fluctuations.

  20. Climate Change Impacts in the Amazon. Review of scientific literature

    SciTech Connect

    NONE

    2006-04-15

    The Amazon's hydrological cycle is a key driver of global climate, and global climate is therefore sensitive to changes in the Amazon. Climate change threatens to substantially affect the Amazon region, which in turn is expected to alter global climate and increase the risk of biodiversity loss. In this literature review the following subjects can be distinguished: Observed Climatic Change and Variability, Predicted Climatic Change, Impacts, Forests, Freshwater, Agriculture, Health, and Sea Level Rise.

  1. Characterization of a gC1qR from the giant freshwater prawn, Macrobrachium rosenbergii.

    PubMed

    Ye, Ting; Huang, Xin; Wang, Xian-Wei; Shi, Yan-Ru; Hui, Kai-Min; Ren, Qian

    2015-03-01

    gC1qR, as a multicompartmental and a multifunctional protein, plays an important role in innate immunity. In this study, a gC1qR homolog (MrgC1qR) in the giant freshwater prawn, Macrobrachium rosenbergii was identified. MrgC1qR, a 258-amino-acid polypeptide, shares high identities with gC1qR from other species. MrgC1qR gene was expressed in different tissues and was highest expressed in the hepatopancreas. In addition, the MrgC1qR transcript was significantly enhanced after 6 h of white spot syndrome virus (WSSV) infection or post 2 h, 24 h of Vibrio anguillarum challenge compared to appropriate controls. Moreover, recombinant MrgC1qR (rMrgC1qR) had bacterial binding activity, the result also revealed that rMrgC1qR could bind pathogen-associated molecular patterns (PAMPs) such as LPS or PGN, suggesting that MrgC1qRmight function as a pathogen-recognition receptor (PRR). Furthermore, glutathione S-transferase (GST) pull-down assays showed that rMrgC1qR with GST-tag could bind to rMrFicolin1 or rMrFicolin2 with His-tag. Altogether, these results may demonstrate a role for MrgC1qR in innate immunity in the giant freshwater prawns. PMID:25555810

  2. Identification and cloning of a transglutaminase from giant freshwater prawn, Macrobrachium rosenbergii, and its transcription during pathogen infection and moulting.

    PubMed

    Liu, Chun-Hung; Chang, Chin-Chyuan; Chiu, Yun-Chih; Cheng, Winton; Yeh, Maw-Sheng

    2011-12-01

    Complementary (c)DNA encoding transglutaminase (TG) messenger (m)RNA of the giant freshwater prawn, Macrobrachium rosenbergii, was cloned from haemocytes by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) using oligonucleotide primers based on the TG sequence of the horseshoe crab, Tachypleus tridentatus; tiger shrimp, Penaeus monodon; kuruma shrimp, Marsupenaeus japonicus; and crayfish, Pacifastacus leniusculus. The 2722-bp cDNA contained an open reading frame (ORF) of 2334 bp, a 72-bp 5'-untranslated region (UTR), and a 316-bp 3'-UTR containing a stop codon and a poly A tail. The molecular mass of the deduced amino acid (aa) sequence (778 aa) was 86.67 kDa with an estimated pI of 5.4. The M. rosenbergii TG (abbreviated MrTG, accession no.: JF309296) contains a typical transglutaminase-like homologue, two putative integrin-binding motifs (RGD), ten glycosylation sites, and four calcium-binding sites; a catalytic triad is present as in arthropod TGs. Sequence comparison and a phylogenetic analysis revealed that shrimp TG can be separated into three subgroups, penaeid TG1, freshwater crustacean TG2 and marine crustacean TG2, and MrTG was more closely related to TG2 than to TG1. MrTG mRNA and TG activities were detected in all tested tissues of M. rosenbergii, with MrTG mainly being synthesised by haemocytes. There was a negative correlation between clotting time of haemolymph, and MrTG expression and TG activity of haemocytes in prawn injected with Lactococcus garvieae. The pattern of MrTG mRNA expression and TG activity in haemocytes exhibited a contrary tendency with clotting time of haemolymph during the moult stages. Those results indicate that cloned MrTG is involved in the defence response, and is probably the major functional TG for haemolymph coagulation in M. rosenbergii. PMID:21854853

  3. Radionuclide tracers of sediment-water interactions on the Amazon shelf

    NASA Astrophysics Data System (ADS)

    Moore, Willard S.; DeMaster, David J.; Smoak, Joseph M.; McKee, Brent A.; Swarzenski, Peter W.

    1996-04-01

    A comprehensive study of a variety of radionuclide tracers has been coupled with other geochemical investigations and with sedimentary and physical oceanographic measurements to elucidate processes and their characteristic time scales at the mouth of the Amazon River. This two-year field study on the Amazon continental shelf involved four cruises designed to provide information during different stages of the river hydrograph. Although the cruises were coordinated with river stage, other physical variables including spring-neap tidal stages, the flow of the North Brazil Current and trade-wind stress caused important effects on the shelf environment. Partitioning of uranium among dissolved, colloidal and particulate phases was investigated during AmasSeds. A detailed examination of uranium water-column behavior during low river discharge found that most (89%) of the uranium near the Amazon River mouth was associated with the particulate phase and that most (92%) of the riverine dissolved-phase uranium was in the colloidal size fraction (0.001-0.4 ?m). A non-conservative uranium/salinity distribution was observed for dissolved uranium, indicating large-scale uranium removal from surface waters with salinities less than 20 ppt. Colloidal uranium was non-conservative across the entire salinity regime, exhibiting removal of colloidal uranium from waters with salinities less than 12 ppt and a significant input at higher salinities. A short-lived particle-reactive tracer, 234Th, was used to evaluate the rates of particle scavenging on the shelf. Suspended-sediment concentrations respond to each turn of the tide, thus limiting the time available for equilibrium to be established between the particles and the tracers. Experiments demonstrated that on the Amazon shelf the partitioning and distribution of trace elements are governed by particle dynamics (particle residence times < sorption times). The high suspended load, including fluid muds, retards the incorporation of adsorbed 234Th into the seabed. Once scavenged, 234Th remains part of the suspended-sediment and fluid-mud inventory for periods of at least 4-8 weeks. Another particle-reactive tracer, 210Pb, was used to evaluate the potential supply of reactive metals from offshore waters to the shelf. As open-ocean waters move into the Amazon mixing zone, in response to the estuarine-like circulation, they lose 210Ph through scavenging processes associated with delta formation. This oceanic input of 210Pb dominates other inputs to the Amazon shelf system. Based on 210Pb analyses from more than 40 ? and kasten cores, the flux of water moving shoreward and depositing 210Pb in the sediments was calculated to be on the order of 6 × 10 161y -1 ˜10 times the riverine flux from the Amazon. The distribution of 210Pb in the sediments suggests that if particle-reactive species (such as certain trace metals) are released in dissolved form on the shelf, they will be scavenged quickly in this turbid environment, with the largest inventories occurring in the foreset beds (although the highest concentrations occur in the bottomset beds). The large landward flow of water indicates that if particle-reactive species are released in the western equatorial Atlantic via aerosol transport or other mechanisms, there is a good chance that a sizeable portion will be buried in the Amazon delta. Fluxes of radium isotopes, 226Ra, 228Ra and 224Ra, from the bottom sediments were used to evaluate sediment resuspension across the shelf. The average flux of 226Ra from the Amazon shelf balanced the annual desorption of 226Ra from river-derived sediments; however, departures between the 226Ra flux and sediment necessary to support the flux occurred for different sampling periods. During falling and low discharge, less sediment entered the system than was required to support the sedimentary desorption 226Ra flux. During rising and high discharge, more sediment entered than was necessary to sustain the 226Ra flux. Considerable recycling of particles between the seabed and water column was required to w

  4. Nitrogen mass balance in the Brazilian Amazon: an update.

    PubMed

    Martinelli, L A; Pinto, A S; Nardoto, G B; Ometto, J P H B; Filoso, S; Coletta, L D; Ravagnani, E C

    2012-08-01

    The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Amazon region. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests (7.7 Tg.yr(-1)), and biological nitrogen fixation in agricultural lands mainly due to the cultivation of a large area with soybean, which is an important nitrogen-fixing crop (1.68 Tg.yr(-1)). The input due to the use of N fertilizers (0.48 Tg.yr(-1)) is still incipient compared to the other two inputs mentioned above. The major output flux is the riverine flux, equal to 2.80 Tg.yr(-1) and export related to foodstuff, mainly the transport of soybean and beef to other parts of the country. The continuous population growth and high rate of urbanization may pose new threats to the nitrogen cycle of the region through the burning of fossil fuel and dumping of raw domestic sewage in rivers and streams of the region. PMID:23011298

  5. Hydrocarbon discoveries in Paleozoic Solimoes basin, Upper Amazon region, Brazil

    SciTech Connect

    Apoluceno, N.; Ferreira, A.; Tsubone, K.

    1989-03-01

    The Solimoes basin, previously known as Upper Amazon basin, is located in northern Brazil and has a prospectable area of more than 300,000 km/sup 2/. The Purus arch, a regional positive feature, separates this basin from the Amazonas basin. As far as the basin geology is concerned, the Solimoes basin is strikingly different from its neighboring basin due to certain structural and stratigraphic peculiarities. Between the Late Jurassic and Early Cretaceous the basin was affected by regional compressional tectonics that generated a series of northeast-southwest-oriented trends. The exploration play in the basin is classic wrench tectonics - elongated dome structures on upthrown blocks of en echelon reverse faults. Despite the problems of working in a tropical forest, Petrobras has made a systematic exploration campaign in the basin since the early 1970s. This effort was compensated by the discovery of two important hydrocarbon-bearing areas: Jurua gas province in 1978 and the Urucu River oil, gas, and condensate province in 1986. The latter, whose commercial oil production was initiated in July 1988, is considered an important marker in the petroleum exploration history of Brazil, particularly with respect to the Paleozoic basins, which total more than 3 million km/sup 2/ of the country's territory.

  6. Tamandua tetradactyla Linnaeus, 1758 (Myrmecophagidae) and Rhodnius robustus Larrousse, 1927 (Triatominae) infection focus by Trypanosoma rangeli Tejera, 1920 (Trypanosomatidae) in Attalea phalerata Mart. ex Spreng (Arecaceae) palm tree in the Brazilian Amazon

    Microsoft Academic Search

    Fernando Braga Stehling Dias; Marion Quartier; Christine A. Romaña; Liléia Diotaiuti; Myriam Harry

    2010-01-01

    A sylvatic infection focus of Trypanosoma rangeli, whose cycle involves the anteater Tamandua tetradactyla and triatomine insect Rhodnius robustus was observed in a pasture-dominated landscape of the rural riparian community of São Tomé located along the Tapajós river in the municipal district of Aveiro (State of Pará, Brazil), the Brazilian Amazon region. During a field work campaign with the objective

  7. Assessing the utility of spectral band operators to reduce the influence of total suspended solids on the relationship between chlorophyll concentration and the bidirectional reflectance factor in Amazon waters

    Microsoft Academic Search

    E. M. L. M. Novo; W. Pereira Filho; J. M. Melack

    2004-01-01

    Measurements of reflectance spectra, total suspended solids (TSS), chlorophyll a+phaeophytin (CLH) and dissolved organic carbon (DOC) plus pH, Secchi disk transparency and water depth were made in lakes associated with the Amazons and Negro rivers upstream from Manaus. Reflectance spectra were acquired between 400 and 900 nm using a spectroradiometer with a nominal resolution of 3 nm. Two spectral band

  8. Effects of sublethal concentrations of phosphamidon, methyl parathion, DDT, and lindane on tissue nitrogen metabolism in the penaeid prawn, Metapenaeus monoceros (Fabricius).

    PubMed

    Reddy, M S; Rao, K V

    1990-02-01

    Changes in midgut gland, muscle, and gill tissue nitrogen metabolic profiles studied in a penaeid prawn, Metapenaeus monoceros, following its exposure to sublethal concentrations of phosphamidon, methyl parathion, DDT, and lindane. In all the pesticide-exposed prawn tissues, ammonia levels were significantly increased and a shift in the nitrogen metabolism toward the synthesis of urea and glutamine was observed. Inhibition of glutamate oxidation to ammonia and alpha-ketoglutarate by glutamate dehydrogenase suggest a mechanism whereby hyperammonemia is reduced by minimizing the addition of further ammonia to the existing elevated ammonia. Aspartate (AAT) and alanine (AlAT) aminotransferases demonstrated an increase in their activity levels, suggesting gluconeogenesis. Pesticide-induced stress also seems to induce ammoniagenesis, which is due to increased deamination of purines. Mechanisms to detoxify the ammonia by enhancing the synthesis of urea and glutamine were observed in the tissues. PMID:1690108

  9. Selective Logging in the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Asner, Gregory P.; Knapp, David E.; Broadbent, Eben N.; Oliveira, Paulo J. C.; Keller, Michael; Silva, Jose N.

    2005-10-01

    Amazon deforestation has been measured by remote sensing for three decades. In comparison, selective logging has been mostly invisible to satellites. We developed a large-scale, high-resolution, automated remote-sensing analysis of selective logging in the top five timber-producing states of the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square kilometers per year (+/-14%) between 1999 and 2002, equivalent to 60 to 123% of previously reported deforestation area. Up to 1200 square kilometers per year of logging were observed on conservation lands. Each year, 27 million to 50 million cubic meters of wood were extracted, and a gross flux of ~0.1 billion metric tons of carbon was destined for release to the atmosphere by logging.

  10. Impacts on Regional Climate of Amazon Deforestation

    Microsoft Academic Search

    Robert E. Dickinson; Patrick Kenneday

    1992-01-01

    A simulation of the climate response to Amazon deforestation has been carried out. Precipitation is decreased on the average by 25% or 1.4 mm\\/day, with ET and runoff both decreasing by 0.7 mm\\/day. Modifications of surface energy balance through change of albedo and roughness are complicated by cloud feedbacks. The initial decrease of the absorption of solar radiation by higher

  11. Smoking Rain Clouds over the Amazon

    Microsoft Academic Search

    M. O. Andreae; D. Rosenfeld; P. Artaxo; A. A. Costa; G. P. Frank; K. M. Longo; M. A. F. Silva-Dias

    2004-01-01

    Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation from 1.5 kilometers above cloud base in pristine clouds to more than 5 kilometers in polluted clouds and more than 7 kilometers in pyro-clouds. Suppression of low-level rainout and aerosol washout allows transport of water and smoke to

  12. Toxicity of the organophosphorous insecticide metamidophos (o,s-dimethyl phosphoramidothioate) to larvae of the freshwater prawn and the blue shrimp

    SciTech Connect

    Juarez, L.M.; Sanchez, J. (Monterrey Institute of Technology, Sonora (Mexico))

    1989-08-01

    The organophosphorous insecticide O,S-dimethyl phosphoramidothioate (Metamidophos, Tamaron, Monitor, Hamidop) is widely used for pest control in tropical crops. If washed down to streams and estuaries its residues could adversely affect populations of commercially important crustaceans, like those of the palaemonid prawn Macrobrachium rosenbergii and the penaeid shrimp Penaeus stylirostris. This paper presents information on the toxicity of O,S-dimethyl phosphoramidothioate to larvae of M. rosenbergii and P. stylirostris.

  13. The increase of immunity and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii by feeding with selenium enriched-diet

    Microsoft Academic Search

    Shieh-Tsung Chiu; Shu-Ling Hsieh; Shinn-Pyng Yeh; Shun-Ji Jian; Winton Cheng; Chun-Hung Liu

    2010-01-01

    The effects of inorganic selenium (Se) (sodium selenate, SSe) and organic selenium (seleno-l-methionine, MSe) supplementation on the immune response, antioxidant status, and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii, were studied. Five experimental diets, including a control diet (without Se enrichment), 0.5 mg (kg diet)?1 of MSe, 1 mg (kg diet)?1 of MSe, 0.5 mg (kg diet)?1 of SSe, and 1 mg

  14. Stressor-specific induction of heat shock protein 70 in the freshwater prawn Macrobrachium malcolmsonii (H. Milne Edwards) exposed to the pesticides endosulfan and carbaryl

    Microsoft Academic Search

    S. Selvakumar; P. Geraldine; S. Shanju; T. Jayakumar

    2005-01-01

    Agricultural run off that is contaminated with pesticides enters water bodies, thereby polluting the aquatic environment. The sensitivity of the freshwater prawn, Macrobrachium malcolmsonii, to such pesticides is well-documented. However, the stress response to sublethal concentrations of pesticides has scarcely been investigated. In the present study, the effect of two different sublethal concentrations (1\\/5th and 1\\/10th of LC50 value) of

  15. Alterations in Concentrations of Protein, Carbohydrate, Glycogen, Free Sugar, and Lipid in the Prawn Macrobrachium malcolmsoniion Exposure to Sublethal Concentrations of Endosulfan

    Microsoft Academic Search

    P. Saravana Bhavan; P. Geraldine

    1997-01-01

    Juveniles ofMacrobrachium malcolmsonii(4.5–5.0 cm in size and 1.0–1.25 g in weight) were exposed to three sublethal concentrations of endosulfan (10.6, 16.0, and 32.0 ng\\/L) for 21 days. Samples were taken from the hemolymph, hepatopancreas, gills, and muscle of representative prawns from each test and control group on the 1st, 8th, 15th, and 21st day after the start of the experiment.

  16. Chagas disease and globalization of the Amazon.

    PubMed

    Briceño-León, Roberto

    2007-01-01

    The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon. PMID:17308715

  17. Analysis of the allergenic proteins in black tiger prawn (Penaeus monodon) and characterization of the major allergen tropomyosin using mass spectrometry.

    PubMed

    Abdel Rahman, Anas M; Rahman, Anas M Abdel; Kamath, Sandip; Lopata, Andreas L; Helleur, Robert J

    2010-08-30

    Crustaceans are the third most prevalent cause of food-induced anaphylaxis after peanuts and tree nuts. The severity of the allergenic proteins depends mainly on the amino acid sequence that induces production of IgE antibodies. In black tiger prawn (Penaeus monodon), the crude protein extract was profiled and its allergenic potency was examined against patient's sera. Proteins having strong immunoreactivity with patient's IgE were characterized using peptide mass fingerprinting (PMF). Tropomyosin (TM) (33 kDa), myosin light chain (20 kDa), and arginine kinase (40 kDa) were identified as allergenic proteins. Tropomyosin, the most abundant and potent allergen, was purified using ion-exchange chromatography for de novo sequencing experiments. Using bottom up tandem mass spectrometry, the full amino acid sequence was achieved by a combination of matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) tandem mass spectrometry (QqToF). Myosin light chain and arginine kinase were also characterized, and their related peptides were de novo sequenced using the same approach. The immunological reactivity of the crude prawn extracts and purified TM samples were analyzed using a large number of patients' sera. A signature peptide was assigned for the TM protein for future quantification work of black tiger prawn TM levels in different matrices (i.e. water, air, food) in the seafood industry. PMID:20658686

  18. Impact of Atmospheric Albedo on Amazon Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Lopes, A. V.; Thompson, S. E.; Dracup, J. A.

    2013-12-01

    The vulnerability of the Amazon region to climate and anthropogenic driven disturbances has been the subject of extensive research efforts, given its importance in the global and regional climate and ecologic systems. The evaluation of such vulnerabilities requires the proper understanding of physical mechanisms controlling water and energy balances and how the disturbances change them. Among those mechanisms, the effects of atmospheric albedo on evapotranspiration have not been fully explored yet and are explored in this study. Evapotranspiration in the Amazon is sustained at high levels across all seasons and represents a large fraction of water and energy surface budgets. In this study, statistical analysis of data from four flux towers installed at Amazon primary forest sites was employed to quantify the impact of atmospheric albedo, mostly resulted from cloudiness, on evapotranspiration and to compare it to the effect of water limitation. Firstly, the difference in eddy-flux derived evapotranspiration at the flux towers under rainy and non-rainy antecedent conditions was tested for significance. Secondly, the same statistical comparison was performed under cloudy and clear sky conditions at hourly and daily time scales, using the reduction in incoming solar radiation as an indicator of cloudiness. Finally, the sensitivity of seasonal evapotranspiration totals to atmospheric albedo resulted from rainfall patterns is evaluated. That was done by sampling daily evapotranspiration estimates from empirical probability distribution functions conditioned to rainfall occurrence and then varying the number of dry days in each season. It was found that light limitation is much more important than water limitation in the Amazon, resulting in up to 43% reduction in daily evapotranspiration. Also, this effect varies by location and by season, the largest impact being in wet season, from December do January. Moreover, seasonal evapotranspiration totals were found to be highly sensitive to the duration of dry spells, set by rainfall patterns, especially during wet seasons and further South from the Equator. These results points to the importance of proper understanding of convective systems and their effects on atmospheric albedo in assessing the vulnerability of Amazon basins to extended dry periods.

  19. Slowing Amazon deforestation through public policy and interventions in beef

    E-print Network

    Napp, Nils

    REVIEW Slowing Amazon deforestation through public policy and interventions in beef and soy supply 70% decline in deforestation in the Brazilian Amazon suggests that it is possible to manage, as did a decline in the demand for new deforestation. The supply chain interventions that fed

  20. Deforestation and Increased Flooding of the Upper Amazon

    Microsoft Academic Search

    A. H. Gentry; J. Lopez-Parodi

    1980-01-01

    The height of the annual flood crest of the Amazon at Iquitos has increased markedly in the last decade. During this same period, there has been greatly increased deforestation in the upper parts of the Amazon watershed in Peru and Ecuador, but no significant changes in regional patterns of precipitation. The change in Amazonian water balance during the last decade

  1. Amazon rainforests green-up with sunlight in dry season

    Microsoft Academic Search

    Alfredo R. Huete; Kamel Didan; Yosio E. Shimabukuro; Piyachat Ratana; Scott R. Saleska; Lucy R. Hutyra; Wenze Yang; Ramakrishna R. Nemani; Ranga Myneni

    2006-01-01

    Metabolism and phenology of Amazon rainforests significantly influence global dynamics of climate, carbon and water, but remain poorly understood. We analyzed Amazon vegetation phenology at multiple scales with Moderate Resolution Imaging Spectroradiometer (MODIS) satellite measurements from 2000 to 2005. MODIS Enhanced Vegetation Index (EVI, an index of canopy photosynthetic capacity) increased by 25% with sunlight during the dry season across

  2. Low Cost, Scalable Proteomics Data Analysis Using Amazon's Cloud

    E-print Network

    Low Cost, Scalable Proteomics Data Analysis Using Amazon's Cloud Computing Services and Open and maintain. #12;Cloud Computing · Distributed or Cloud computing allows for the use of virtual computers Web Services (AWS) · EC2 ­ Amazon Elastic Compute Cloud "a web service that provides resizable compute

  3. A Limnological Examination of the Southwestern Amazon, Madre de Dios, Peru

    NASA Astrophysics Data System (ADS)

    Belcon, Alana Urnesha

    This dissertation investigates the limnology of the southwestern Peruvian Amazon centered on the Madre de Dios department by examining first the geomorphology and then the ecology and biogeochemistry of the region's fluvial systems. Madre de Dios, Peru is world renowned for its prolific biodiversity and its location within the Andes biodiversity hotspot. It is also a site of study regarding the development of the Fitzcarrald Arch and that feature's geomorphological importance as the drainage center for the headwaters of the Madeira River---the Amazon's largest tributary and as well as its role as a physical divider of genetic evolution in the Amazon. Though each of these has been studied by a variety of prominent researchers, the ability to investigate all the aspects of this unique region is hampered by the lack of a regional geomorphological map. This study aims to fill that gap by using remote sensing techniques on digital elevation models, satellite imagery and soil, geology and geoecological maps already in publication to create a geomorphological map. The resulting map contains ten distinct landform types that exemplify the dominance of fluvial processes in shaping this landscape. The river terraces of the Madre de Dios River are delineated in their entirety as well as the various dissected relief units and previously undefined units. The demarcation of the boundaries of these geomorphic units will provide invaluable assistance to the selection of field sites by future researchers as well as insights into the origin of the high biodiversity indices of this region and aid in planning for biodiversity conservation. Secondly this study examines 25 tropical floodplain lakes along 300 km of the Manu River within the Manu National Park in the Madre de Dios department. Alternative stable state and regime shifts in shallow lakes typically have been examined in lakes in temperate and boreal regions and within anthropogenically disturbed basins but have rarely been studied in tropical or in undisturbed regions. In contrast this study focuses on a tropical region of virtually no human disturbance and evaluates the effects of hydrological variability on ecosystem structure and dynamics. Using satellite imagery a 23 yr timeline of ecological regime shifts in Amazon oxbow lakes or "cochas" is reconstructed. The study shows that almost 25% of the river's floodplain lakes experience periodic abrupt vegetative changes with an average 3.4% existing in an alternative stable state in any given year. State changes typically occur from a stable phytoplankton-dominated state to a short lived, <3 yr, floating macrophytic state and often occur independent of regional flooding. We theorize that multiple dynamics, both internal and external, drive vegetative regime shifts in the Manu but insufficient data yet exists in this remote region to identify the key processes. To complete the investigation of tropical limnology the third study compares and contrasts the nutrient-productivity ration of floodplain and non-floodplain lakes globally and regionally. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established with phosphorus generally viewed as the most limiting factor to productivity. Most of these studies, however, have focused on northern, temperate regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on floodplain lakes which are semi or permanently connected to the river. This study examines the relationship between nutrients and productivity in floodplain lakes globally through an extensive literature synthesis. Values for total phosphorus, total nitrogen and chlorophyll-a were collected for 523 floodplain lakes, represented by 288 data points while 551 data points were collected for 5444 non-floodplain lakes. Analysis revealed that globally, floodplain lakes do not show any significant difference in the total phosphorus/chlorophyll-a relationship from that found in non-floodpl

  4. Surface Water Dynamics in the Amazon Basin: Application of Satellite Radar Altimetry

    NASA Astrophysics Data System (ADS)

    Birkett, C. M.; Mertes, L. A.; Dunne, T.; Costa, M. H.; Jasinski, M. J.

    2001-05-01

    Satellite radar altimetry has the ability to monitor variations in surface water height (or stage) for large lakes, wetlands, rivers, and their floodplains. As part of an international programme a complete altimetric analysis of the Amazon Basin is being undertaken based on the ERS and TOPEX/POSEIDON (T/P) satellite missions. Here, an updated and more rigorous evaluation of the T/P data is presented for the first 7.5 years of the mission. For an initial study group of 230 targets, stage variability can be observed for 30-50%, the range reflecting the clarity of the noted seasonality. An assessment of the instrument performance confirms that the minimum river width attainable is set at 1 km in the presence of some inundated floodplain. This does allow observation of many of the large tributaries, but in the outer regions, mountainous terrain additionally places severe limitations. With ground-based stage measurements, validation exercises show that the overall 1992-1999 results can be accurate to 0.4 m rms, but that this is highly variable (>0.13 m) depending of target width and season. The Solimoes and Amazon are particularly well observed with seasonal altimetric amplitudes <13 m, and variations in peak level timing from May to July. The gradient of the main stem is also estimated ranging from 1.4 cm/km for downstream reaches to 3.8 cm/km for more upstream regions. The seasonal variability of this gradient is also explored, noting that downstream of the confluence of the Negro river, a hysteresis characteristic is in effect, suggesting a kinematic nature to the peak-flow flood wave. All the altimetric results demonstrate that the T/P mission is successfully contributing to this long-term surface water dynamics programme.

  5. Incorporating SST seasonal forecast into drought and fire predictions in western Amazon

    NASA Astrophysics Data System (ADS)

    Fernandes, K.; Baethgen, W.; Bernardes, S.; DeFries, R. S.; DeWitt, D. G.; Goddard, L. M.; Lavado, W.; Lee, D.; Padoch, C.; Pinedo-Vasquez, M.; Uriarte, M.

    2011-12-01

    The prevailing wet climate in western Amazon is not favorable to the natural occurrence of fires. In the last decade, however, the region has experienced some of the most catastrophic fires in the history of Amazonia. In 2005 over 300,000 ha of burned rain forest in the Brazilian state of Acre and around 22,000 ha in the province of Coronel Portillo in Peru. In 2010 another severe drought prompted the Bolivian government to declare a state of emergency due to widespread fires and one major Amazon tributary, the Negro River, registered its lowest water lever in over 100 years. Fire dynamics in humid tropical forests are complex and involve a swath of socio-economic aspects, including replacement of forests by crops and pastures, fires for agricultural maintenance, timber extraction and infrastructure development all of which result in greater vulnerability of the natural system to fires. Despite the importance of these effects at fine spatial scales, we find that precipitation anomalies are the main drivers of interannual fire variability at large spatial and temporal scales in western Amazonia. Using real-time SST forecasts for the north tropical Atlantic sector we are able to predict precipitation and fire anomalies during the dry season months. The 2010 positive fire anomalies predicted by the 2010 seasonal forecasts for MJJ, JJA, and JAS are in agreement with the negative predicted 2010 JAS SPI and observed precipitation anomalies estimated by TRMM. Our results show that ECHAM-GML MJJ SST can be used to predict western Amazon JAS precipitation and fire anomalies as early as April, information that can be regionally used as an early warning system product.

  6. Impacts on regional climate of Amazon deforestation

    SciTech Connect

    Dickinson, R.E.; Kennedy, P. (Arizona Univ., Tucson (United States) NCAR, Boulder, CO (United States))

    1992-10-01

    A simulation of the climate response to Amazon deforestation has been carried out. Precipitation is decreased on the average by 25 percent or 1.4 mm/day, with ET and runoff both decreasing by 0.7 mm/day. Modifications of surface energy balance through change of albedo and roughness are complicated by cloud feedbacks. The initial decrease of the absorption of solar radiation by higher surface albedos is largely cancelled by a reduction in cloud cover, but consequent reduction in downward longwave has a substantial impact on surface energy balance. Smoke aerosols might have an effect comparable to deforestation during burning season. 8 refs.

  7. Surface water dynamics in the Amazon Basin: Application of satellite radar altimetry

    NASA Astrophysics Data System (ADS)

    Birkett, C. M.; Mertes, L. A. K.; Dunne, T.; Costa, M. H.; Jasinski, M. J.

    2002-10-01

    Satellite radar altimetry has the ability to monitor variations in surface water height (stage) for large wetlands, rivers, and associated floodplains. A clear advantage is the provision of data where traditional gauges are absent. As part of an international program, a complete altimetric analysis of the Amazon Basin is being undertaken. Here, an updated and more rigorous evaluation of the TOPEX/POSEIDON (T/P) data set is presented for the first ˜7.5 years of the mission. With an initial study group of 230 targets, height variability at many ungauged locations can be observed for 30-50%, the range reflecting the clarity of the variations in lieu of instrument limitations. An assessment of the instrument performance confirms that the minimum river width attainable is ˜1 km in the presence of some inundated floodplain. This constraint does allow observation of the main stem (Solimões/Amazon) and the larger tributaries, but rugged terrain in the vicinity of the target additionally places severe limitations on data retrieval. First-order validation exercises with the deduced 1992-1999 time series of stage fluctuations reveal accuracies ranging from tens of centimeters to several meters (mean ˜1.1 m rms). Altimetric water levels in the Solimões and Amazon are particularly well defined with amplitudes <13 m and variations in peak-level timing from May to July. The water-surface gradient of the main stem is found to vary both spatially and temporally, with values ranging from 1.5 cm/km downstream to 4.0 cm/km for more upstream reaches. In agreement with ground-based estimates, the seasonal variability of the gradients reveals that the hysteresis characteristic of the flood wave varies along the main stem and the derived altimetric velocity of this flood wave is estimated to be ˜0.35 m/s. Overall, the altimetric results demonstrate that the T/P mission is successfully monitoring the transient flood waves of this continental-scale river basin.

  8. Oxidation and reduction rates for organic carbon in the Amazon mainstream tributary and floodplain, inferred from distributions of dissolved gases

    NASA Technical Reports Server (NTRS)

    Richey, Jeffrey E.; Devol, Allan H.; Wofsy, Steven C.; Victoria, Reynaldo; Riberio, Maria N. G.

    1986-01-01

    Concentrations of CO2, O2, CH4, and N2O in the Amazon River system reflect an oxidation-reduction sequence in combination with physical mixing between the floodplain and the mainstem. Concentrations of CO2 ranged from 150 microM in the Amazon mainstem to 200 to 300 microM in aerobic waters of the floodplain, and up to 1000 microM in oxygen-depleted environments. Apparent oxygen utilization (AOU) ranged from 80 to 250 microM. Methane was highly supersaturated, with concentrations ranging from 0.06 microM in the mainstem to 100 microM on the floodplain. Concentrations of N2O were slightly supersaturated in the mainstem, but were undersaturated on the floodplain. Fluxes calculated from these concentrations indicated decomposition of 1600 g C sq m y(-1) of organic carbon in Amazon floodplain waters. Analysis of relationships between CH4, O2, and CO2 concentrations indicated that approximately 50 percent of carbon mineralization on the floodplain is anaerobic, with 20 percent lost to the atmoshphere as CH4. The predominance of anaerobic metabolism leads to consumption of N2O on the flood plane. Elevated concentrations of CH4 in the mainstem probably reflect imput from the floodplain, while high levels of CO2 in the mainstem are derived from a combination of varzea drainage and in situ respiration.

  9. The Hill of Six Lakes revisited: new data and re-evaluation of a key Pleistocene Amazon site

    NASA Astrophysics Data System (ADS)

    D'Apolito, Carlos; Absy, Maria Lúcia; Latrubesse, Edgardo M.

    2013-09-01

    The new analyses of a sedimentary record of Lake Pata in the Hill of Six Lakes, in NW Amazon and its correlation with other Quaternary proxy records in the region provide new insights regarding the vegetation and climate of the lowland forest during the Last Glacial. Despite what has been reported previously in the literature, the sedimentary and pollen records are not continuous. The hill remained forested; however, clear signals of structural change are seen in the record, which indicate that the area experienced a significantly drier climate during the Last Glacial Maximum (LGM). The herbs and taxa that are known to be more dominant in seasonally dry forests were all more abundant during the glacial part of the record, and the cool-adapted elements were mixed with warm lowland elements, which indicates a temperature depression. A comparison of the palaeoecological data with other regional geoenvironmental records of the Upper Negro River basin and other areas of the Amazon provides additional support for a cooler and more seasonal environment during the middle Pleniglacial, which then became drier during the LGM. A “wet” LGM is strongly refuted; therefore, the palaeoclimatic and ecological models that used the previous proxy data from Six Lakes to sustain “wet” conditions and a “continuous forest record” during the LGM to reconstruct the palaeoenvironmental conditions in the Amazon should be reviewed.

  10. Kinship and Social Behavior of Lowland Tapirs (Tapirus terrestris) in a Central Amazon Landscape

    PubMed Central

    Pinho, Gabriela M.; Gonçalves da Silva, Anders; Hrbek, Tomas; Venticinque, Eduardo M.; Farias, Izeni P.

    2014-01-01

    We tested the hypothesis that tapirs tolerate individuals from adjacent and overlapping home ranges if they are related. We obtained genetic data from fecal samples collected in the Balbina reservoir landscape, central Amazon. Samples were genotyped at 14 microsatellite loci, of which five produced high quality informative genotypes. Based on an analysis of 32 individuals, we inferred a single panmictic population with high levels of heterozygosity. Kinship analysis identified 10 pairs of full siblings or parent-offspring, 10 pairs of half siblings and 25 unrelated pairs. In 10 cases, the related individuals were situated on opposite margins of the reservoir, suggesting that tapirs are capable of crossing the main river, even after damming. The polygamous model was the most likely mating system for Tapirus terrestris. Moran's I index of allele sharing between pairs of individuals geographically close (<3 km) was similar to that observed between individual pairs at larger distances (>3 km). Confirming this result, the related individuals were not geographically closer than unrelated ones (W?=?188.5; p?=?0.339). Thus, we found no evidence of a preference for being close to relatives and observed a tendency for dispersal. The small importance of relatedness in determining spatial distribution of individuals is unusual in mammals, but not unheard of. Finally, non-invasive sampling allowed efficient access to the genetic data, despite the warm and humid climate of the Amazon, which accelerates DNA degradation. PMID:24671057

  11. Origin of Amazon mudbanks along the northeastern coast of South America

    USGS Publications Warehouse

    Allison, M.A.; Lee, M.T.; Ogston, A.S.; Aller, R.C.

    2000-01-01

    Seismic profiles, sediment cores, and water column measurements were collected along the northeastern coast of Brazil to examine the origin of mudbanks in the Amazon coastal mud belt. These 10-60-km-long, shore-attached features previously had been observed to migrate along the 1200 km coast of the Guianas in response to wave forcing. CHIRP (3.5 kHz) seismic profiles of the shoreface and inner shelf located two mudbanks updrift of the previous eastern limit in French Guiana. 210Pb geochronology shows that these two banks are migrating to the northwest over a relict mud surface in 5-20 m water depth. The mudbanks are 3-4 m thick and are translating over a modern shoreface mud wedge deposited by previous mudbank passage in < 5 m water depth. Initial mudbank development is taking place on the intertidal and shallow subtidal mudflats at Cabo Cassipore, associated with an alongshore-accreting clinoform feature. Sediment trapping in this area is controlled by the nearshore presence of strong water column stratification produced by the enormous Amazon freshwater discharge on the shelf and by proximity to the Cassipore River estuary. Seasonal and decadal periods of sediment supply and starvation in this area likely are controlled by variations in northwest trade wind intensity. (C) 2000 Elsevier Science B.V.

  12. Characterization of nitrogen-fixing cyanobacteria in the Brazilian Amazon floodplain.

    PubMed

    Fiore, Marli de Fátima; Neilan, Brett A; Copp, Janine N; Rodrigues, Jorge L M; Tsai, Siu M; Lee, Hung; Trevors, Jack T

    2005-12-01

    The diversity of the free-living nitrogen-fixing cyanobacterial community in the floodplain sediments along the Solimões and Amazon Rivers and some of their tributaries (Japurá, Negro and Madeira) was investigated. Five cyanobacterial genera were morphologically identified, four of which (Nostoc, Calothrix, Cylindrospermum and Fischerella) have not previously been isolated from the Brazilian Amazon floodplain. Nostoc strains were the most commonly found heterocyst-forming cyanobacteria. Five strains (N. muscorum CENA18 and CENA61, N. piscinale CENA21, Cylindrospermum sp. CENA33 and Fischerella sp. CENA19) were selected for growth measurement, ability to fix N2 and phylogenetic analysis, based on their widespread distribution and morphological distinction. Molecular analyses employing 16S rRNA sequences indicated that some of the isolates may represent novel cyanobacterial species. Dinitrogen fixed by these strains was measured indirectly as acetylene reduction activity and ranged from 11.5 to 22.2 nmol C2H4 microg Chl a(-1) h(-1). These results provide evidence of widespread and importance of nitrogen-fixing cyanobacteria as a source of N inputs in the Amazonian ecosystem. PMID:16289234

  13. Relationship of Tooth Wear to Chronological Age among Indigenous Amazon Populations

    PubMed Central

    Vieira, Elma Pinto; Barbosa, Mayara Silva; Quintão, Cátia Cardoso Abdo; Normando, David

    2015-01-01

    In indigenous populations, age can be estimated based on family structure and physical examination. However, the accuracy of such methods is questionable. The aim of this cross-sectional study was to evaluate occlusal tooth wear related to estimated age in the remote indigenous populations of the Xingu River, Amazon. Two hundred and twenty three semi-isolated indigenous subjects with permanent dentition from the Arara (n = 117), Xicrin-Kayapó (n = 60) and Assurini (n = 46) villages were examined. The control group consisted of 40 non-indigenous individuals living in an urban area in the Amazon basin (Belem). A modified tooth wear index was applied and then associated with chronological age by linear regression analysis. A strong association was found between tooth wear and chronological age in the indigenous populations (p <0.001). Tooth wear measurements were able to explain 86% of the variation in the ages of the Arara sample, 70% of the Xicrin-Kaiapó sample and 65% of the Assurini sample. In the urban control sample, only 12% of ages could be determined by tooth wear. These findings suggest that tooth wear is a poor estimator of chronological age in the urban population; however, it has a strong association with age for the more remote indigenous populations. Consequently, these findings suggest that a simple tooth wear evaluation method, as described and applied in this study, can be used to provide a straightforward and efficient means to assist in age determination of newly contacted indigenous groups. PMID:25602501

  14. Biogeochemical process in an Amazon basin floodplain - Lago Grande de Curuai, Brazil

    NASA Astrophysics Data System (ADS)

    Mauro Moura, Jose; Victoria, Reynaldo; Oliveira, Eliese; Ometto, Jean; Martinelli, Luis; Mitsuya, Miyuki

    2014-05-01

    The work was performed during in the Amazon, mainly focusing in the study of a typical floodplain (Lago Grande de Curuai) located on the right bank of the Amazon River. During the low water phase, the mean concentration of SS was 320,0 mg L-1, which in turn, is 13-fold the mean concentration (24,5 mg L-1) measured during the high water phase. During the rising water phase the concentration of SS decreased significantly to 83,0 mg L-1 Concentration of DOC were very similar ( 4 mg L-1) along the rising, high, and falling water phases, and increased significantly during the low water phase reaching mean value equal to 6,4 mg L-1. The C:N varied from 7 to 9,2 showing the lowest value during the low water phase and highest values during the rising water. The d15N values showed similar trend, varying from 4per mil during the low water phase and reaching the most depleted (

  15. Kinship and social behavior of lowland tapirs (Tapirus terrestris) in a central Amazon landscape.

    PubMed

    Pinho, Gabriela M; Gonçalves da Silva, Anders; Hrbek, Tomas; Venticinque, Eduardo M; Farias, Izeni P

    2014-01-01

    We tested the hypothesis that tapirs tolerate individuals from adjacent and overlapping home ranges if they are related. We obtained genetic data from fecal samples collected in the Balbina reservoir landscape, central Amazon. Samples were genotyped at 14 microsatellite loci, of which five produced high quality informative genotypes. Based on an analysis of 32 individuals, we inferred a single panmictic population with high levels of heterozygosity. Kinship analysis identified 10 pairs of full siblings or parent-offspring, 10 pairs of half siblings and 25 unrelated pairs. In 10 cases, the related individuals were situated on opposite margins of the reservoir, suggesting that tapirs are capable of crossing the main river, even after damming. The polygamous model was the most likely mating system for Tapirus terrestris. Moran's I index of allele sharing between pairs of individuals geographically close (<3 km) was similar to that observed between individual pairs at larger distances (>3 km). Confirming this result, the related individuals were not geographically closer than unrelated ones (W?=?188.5; p?=?0.339). Thus, we found no evidence of a preference for being close to relatives and observed a tendency for dispersal. The small importance of relatedness in determining spatial distribution of individuals is unusual in mammals, but not unheard of. Finally, non-invasive sampling allowed efficient access to the genetic data, despite the warm and humid climate of the Amazon, which accelerates DNA degradation. PMID:24671057

  16. Applications of TOPS Anomaly Detection Framework to Amazon Drought Analysis

    NASA Astrophysics Data System (ADS)

    Votava, P.; Nemani, R. R.; Ganguly, S.; Michaelis, A.; Hashimoto, H.

    2011-12-01

    Terrestrial Observation and Prediction System (TOPS) is a flexible modeling software system that integrates ecosystem models with frequent satellite and surface weather observations to produce ecosystem nowcasts (assessments of current conditions) and forecasts useful in natural resources management, public health and disaster management. We have been extending the Terrestrial Observation and Prediction System (TOPS) to include capability for automated anomaly detection and analysis of both on-line (streaming) and off-line data. While there are large numbers of anomaly detection algorithms for multivariate datasets, we are extending this capability beyond the anomaly detection itself and towards an automated analysis that would discover the possible causes of the anomalies. In order to best capture the knowledge about data hierarchies, Earth science models and implied dependencies between anomalies and occurrences of observable events such as urbanization, deforestation, or fires, we have developed an ontology to serve as a knowledge base. The knowledge is captured using OWL ontology language, where connections are defined in a schema that is later extended by including specific instances of datasets and models. We have integrated this knowledge base with a framework for deploying an ensemble of anomaly detection algorithms on large volumes of Earth science datasets and applied it to specific scientific applications that support research conducted by our group. In one early application, we were able to process large number of MODIS, TRMM, CERES data along with ground-based weather and river flow observations to detect the evolution of 2010 drought in the Amazon, identify the affected area, and publish the results in three weeks. A similar analysis of the 2005 drought using the same data sets took nearly 2 years, highlighting the potential contribution of our anomaly framework in accelerating scientific discoveries.

  17. Rivers as Political Boundaries: Peru and its Dynamic Borders

    NASA Astrophysics Data System (ADS)

    Abad, J. D.; Escobar, C.; Garcia, A. M. P.; Ortals, C.; Frias, C. E.; Vizcarra, J.

    2014-12-01

    Rivers, although inherently dynamic, have been chosen as political boundaries since the beginning of colonization for several reasons. Such divisions were chosen namely for their defensive capabilities and military benefits, and because they were often the first features mapped out by explorers. Furthermore, rivers were indisputable boundaries that did not require boundary pillars or people to guard them. However, it is important to understand the complexities of a river as a boundary. All rivers inevitably change over time through processes such as accretion, deposition, cut-off, or avulsion, rendering a political boundary subject to dispute. Depending upon the flow, size, and surrounding land, a river will migrate differently than others. As these natural features migrate one country loses land while another gains land leading to tension between legal rigidity and fluid dynamism. This in turn can manifest in social disruption due to cultural differences, political upheaval, or conflict risk as a result of scarce water resources. The purpose of this research is to assess the temporal and spatial variability of the political boundaries of Peru that follow rivers. Peru shares borders with Colombia, Brazil, Bolivia, Chile, and Ecuador. A large part of its northern border with Colombia follows the Putumayo River and later the Amazon River. Part of its eastern border with Brazil follows the Yavari River and later the Yaquirana River. These rivers are natural features used as political boundaries yet they differ in how each migrates. By means of a spatial and temporal analysis of satellite images it was possible to obtain erosion and deposition areas for the Putumayo River, the portion of the Amazon River that is part of the Peruvian boundary, the Yavari River, and the Yaquirana River. The erosion and deposition areas were related to land distribution among Peru, Colombia, and Brazil. By examining the Digital Elevation Model one can see how the altitude of the surrounding land affects the watersheds and thus better understand the dynamic of rivers. Ultimately, this research combines data regarding the morphodynamics of these rivers with historical insight on border treaties in order to gain a comprehensive understanding of political implications and social repercussions of dynamic boundaries.

  18. Prudhoe Bay COLVILLE RIVER

    E-print Network

    Fairbanks Juneau Tok Nome Circle Barrow Prudhoe Bay TANANA RIVER LOWER YUKON KOYUKUK RIVER COPPER RIVER COLVILLE RIVER SUSITNA RIVER BARROW ALASKA CENTRAL YUKON NORTON SOUND UPPER YUKON RIVER PORCUPINE RIVER UPPER KUSKOKWIM RIVER NUSHAGAK RIVER LOWER KUSKOKWIM RIVER PRUDHOE BAY CANADA KOBUK- SELAWIK

  19. Patents on periphery of the Amazon rainforest.

    PubMed

    de Moura, Emanoel G; Araújo, José R G; Monroe, Paulo H M; de O Nascimento, Ivaneide; Aguiar, Alana C F

    2009-06-01

    In the humid tropics, on the edges of the Amazon forest, the technological challenges to establishing and maintaining productive and sustainable agricultural systems have yet to be overcome. The groups involved in agriculture in the north of Brazil still engage in the practice of slash and burn in order to prepare and fertilize the soil. This produces negative effects for the local and global environment, without the counter-effect of providing social benefits to rural communities. Whether this process continues is of fundamental importance to many countries because it means that slash and burn agriculture is advancing on the Amazon rainforest, with a negative effect on every dimension of national policy. Beyond social political problems the biggest challenge for researchers in the field of tropical agriculture is to offer technological alternatives that can sustain agriculture in soils derived from sedimentary rocks that have been subjected to a high degree of weathering. In this article patented information is also discussed. Experiments undertaken in this region recommend taking advantage of the rapid growth of plants in the tropics. We aimed at proposing a suitable alternative system for a sustainable soil management in the particular conditions of humid tropics, named as "no-till in alley cropping using tree leguminous mulch." This system offers the advantages of: bringing together, in the same space and at the same time, the processes of cultivation and the regeneration of soil fertility. PMID:20653534

  20. Precipitation recycling in the Amazon basin

    NASA Technical Reports Server (NTRS)

    Eltahir, E. A. B.; Bras, R. L.

    1994-01-01

    Precipitation recycling is the contribution of evaporation within a region to precipitation in that same region. The recycling rate is a diagnostic measure of the potential for interactions between land surface hydrology and regional climate. In this paper we present a model for describing the seasonal and spatial variability of the recycling process. The precipitation recycling ratio, rho, is the basic variable in describing the recycling process. Rho is the fraction of precipitation at a certain location and time which is contributed by evaporation within the region under study. The recycling model is applied in studyiing the hydrologic cycle in the Amazon basin. It is estimated that about 25% of all the rain that falls in the Amazon basin is contributed by evaporation within the basin. This estimate is based on analysis of a data set supplied by the European Centre for Medium-range Weather Forecasts (ECMWF). The same analysis is repeated using a different data set from the Geophysical Fluid Dynamics Laboratory (GFDL). Based on this data set, the recycling ratio is estimated to be 35%. The seasonal variability of the recycling ratio is small compared with the yearly average. The new estimates of the recycling ratio are compared with results of previous studies, and the differences are explained.

  1. A Preliminary Study of the Algicidal Mechanism of Bioactive Metabolites of Brevibacillus laterosporus on Oscillatoria in Prawn Ponds

    PubMed Central

    Jia, Wen; Huang, Xianghu; Li, Changling

    2014-01-01

    The algae, Oscillatoria, is commonly found in prawn ponds and can lead to reduced productivity. We examined metabolites of the bacteria Brevibacillus laterosporus for algicidal qualities. To determine the possible algicidal mechanisms of these bioactive metabolites, different amounts of sterile filtrate of bacterial suspensions were added to cultures containing Oscillatoria. The dry weight, the concentrations of chlorophyll-a (chl-a), phycobiliprotein (PC, phycocyanin; APC, allophycocyanin; PE, phycoerythrin), and MDA (malondialdehyde) and the activities of SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase) of algae were measured during the algicidal application. The results showed that lower concentrations of the sterile filtrate (addition ? 4?mL) accelerated the growth rate of Oscillatoria, but significant inhibition and lysis were observed with higher concentrations (addition ? 8?mL). In two trials (the additions were 8?mL and 10?mL, respectively), the algal dry weights were reduced by 26.02% and 45.30%, and the chl-a concentrations were decreased by 46.88% and 63.73%, respectively, after seven days. During the algicidal treatment, the concentrations of PC, APC, PE, and MDA and the activities of SOD, POD, and CAT were significantly increased in the early cultivation and declined quickly at later stages. Finally, the algae-lysing mechanism of the bioactive metabolites of the bacteria Brevibacillus laterosporus on Oscillatoria had been proposed. PMID:24744687

  2. A preliminary study of the algicidal mechanism of bioactive metabolites of Brevibacillus laterosporus on Oscillatoria in prawn ponds.

    PubMed

    Jia, Wen; Huang, Xianghu; Li, Changling

    2014-01-01

    The algae, Oscillatoria, is commonly found in prawn ponds and can lead to reduced productivity. We examined metabolites of the bacteria Brevibacillus laterosporus for algicidal qualities. To determine the possible algicidal mechanisms of these bioactive metabolites, different amounts of sterile filtrate of bacterial suspensions were added to cultures containing Oscillatoria. The dry weight, the concentrations of chlorophyll-a (chl-a), phycobiliprotein (PC, phycocyanin; APC, allophycocyanin; PE, phycoerythrin), and MDA (malondialdehyde) and the activities of SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase) of algae were measured during the algicidal application. The results showed that lower concentrations of the sterile filtrate (addition ? 4 mL) accelerated the growth rate of Oscillatoria, but significant inhibition and lysis were observed with higher concentrations (addition ? 8 mL). In two trials (the additions were 8 mL and 10 mL, respectively), the algal dry weights were reduced by 26.02% and 45.30%, and the chl-a concentrations were decreased by 46.88% and 63.73%, respectively, after seven days. During the algicidal treatment, the concentrations of PC, APC, PE, and MDA and the activities of SOD, POD, and CAT were significantly increased in the early cultivation and declined quickly at later stages. Finally, the algae-lysing mechanism of the bioactive metabolites of the bacteria Brevibacillus laterosporus on Oscillatoria had been proposed. PMID:24744687

  3. Transcriptome analysis of eyestalk and hemocytes in the ridgetail white prawn Exopalaemon carinicauda: assembly, annotation and marker discovery.

    PubMed

    Li, Jitao; Li, Jian; Chen, Ping; Liu, Ping; He, Yuying

    2015-01-01

    The ridgetail white prawn Exopalaemon carinicauda is one of major economic mariculture species in eastern China. The deficiency of genomic and transcriptomic data is becoming the bottleneck of further researches on its good traits. In the present study, 454 pyrosequencing was undertaken to investigate the transcriptome profiles of E. carinicauda. A collection of 1,028,710 sequence reads (459.59 Mb) obtained from cDNA prepared from eyestalk and hemocytes was assembled into 162,056 expressed sequence tags (ESTs). Of these, 29.88 % of 48,428 contigs and 70.12 % of 113,628 singlets possessed high similarities to sequences in the GenBank non-redundant database, with most significant (E value <1e(-10)) unigenes matches occurring with crustacean and insect sequences. KEGG analysis of unigenes identified putative members of biological pathways related to growth and immunity. In addition, we obtained a total of putative 125,112 SNPs and 13,467 microsatellites. These results will contribute to the understanding of the genome makeup and provide useful information for future functional genomic research in E. carinicauda. PMID:25266235

  4. Microwave-assisted derivatisation and LC-MS/MS determination of nitrofuran metabolites in farm-raised prawns (Penaeus monodon).

    PubMed

    Palaniyappan, Venkatesh; Nagalingam, Arun Kumar; Ranganathan, Hari Prasad; Kandhikuppam, Krishnamoorthy Bharathi; Kothandam, Hari Prasath; Vasu, Soumya

    2013-01-01

    A new microwave-assisted derivatisation and LC-MS/MS method has been developed for the analysis of nitrofuran metabolites - 3-amino-5-morpholino-methyl-1,3-oxa-zolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ), 1-aminohydantoin (AHD) and semicarbazide (SEM) - in farm-raised prawns (Penaeus monodon) from the coastal regions of South India. Analysis was carried out by reverse-phase column (Phenomenex Luna C18) with gradient elution using mobile phase A (0.02% acetic acid in water) and mobile phase B (0.02% acetic acid in acetonitrile), at a flow rate of 200 ?l min(-1) and an injection volume of 20 ?l. Microwave-assisted derivatisation was achieved in 6 min with good recovery. The results showed that the samples collected from Andhra Pradesh and Karnataka contained residues of nitrofuran metabolites in the range from 5.0 to 40 ng g(-1). This work emphasises the importance of ensuring the safety of seafood and that a new method of derivatisation is applicable for the analysis of nitrofuran metabolites in seafood. PMID:23883190

  5. Molecular analysis of the freshwater prawn Macrobrachium olfersii (Decapoda, Palaemonidae) supports the existence of a single species throughout its distribution.

    PubMed

    Rossi, Natália; Mantelatto, Fernando Luis

    2013-01-01

    Macrobrachium olfersii is an amphidromous freshwater prawn, widespread along the eastern coasts of the Americas. This species shows great morphological modifications during ontogenesis, and several studies have verified the existence of a wide intraspecific variation. Because of this condition, the species is often misidentified, and several synonyms have been documented. To elucidate these aspects, individuals of M. olfersii from different populations along its range of distribution were investigated. The taxonomic limit was established, and the degree of genetic variability of this species was described. We extracted DNA from 53 specimens of M. olfersii, M. americanum, M. digueti and M. faustinum, which resulted in 84 new sequences (22 of 16S mtDNA, 45 of Cythocrome Oxidase I (COI) mtDNA, and 17 of Histone (H3) nDNA). Sequences of three genes (single and concatenated) from these species were used in the Maximum Likelihood and Bayesian Inference phylogenetic analyses and COI sequences from M. olfersii were used in population analysis. The genetic variation was evaluated through the alignment of 554 bp from the 16S, 638 bp from the COI, and 338 bp from the H3. The rates of genetic divergence among populations were lower at the intraspecific level. This was confirmed by the haplotype net, which showed a continuous gene flow among populations. Although a wide distribution and high morphological intraspecific variation often suggest the existence of more than one species, genetic similarity of Caribbean and Brazilian populations of M. olfersii supported them as a single species. PMID:23382941

  6. Spectrometry of pasture condition and biogeochemistry in the central Amazon

    NASA Astrophysics Data System (ADS)

    Asner, Gregory P.; Townsend, Alan R.; Bustamante, Mercedes M. C.

    Regional analyses of Amazon cattle pasture biogeochemistry are difficult due to the complexity of human, edaphic, biotic and climatic factors and persistent cloud cover in satellite observations. We developed a method to estimate key biophysical properties of Amazon pastures using hyperspectral reflectance data and photon transport inverse modeling. Remote estimates of live and senescent biomass were strongly correlated with plant-available forms of soil phosphorus and calcium. These results provide a basis for monitoring pasture condition and biogeochemistry in the Amazon Basin using spaceborne hyperspectral sensors.

  7. Amazon forests green-up during 2005 drought.

    PubMed

    Saleska, Scott R; Didan, Kamel; Huete, Alfredo R; da Rocha, Humberto R

    2007-10-26

    Coupled climate-carbon cycle models suggest that Amazon forests are vulnerable to both long- and short-term droughts, but satellite observations showed a large-scale photosynthetic green-up in intact evergreen forests of the Amazon in response to a short, intense drought in 2005. These findings suggest that Amazon forests, although threatened by human-caused deforestation and fire and possibly by more severe long-term droughts, may be more resilient to climate changes than ecosystem models assume. PMID:17885095

  8. Spectrometry of Pasture Condition and Biogeochemistry in the Central Amazon

    NASA Technical Reports Server (NTRS)

    Asner, Gregory P.; Townsend, Alan R.; Bustamante, Mercedes M. C.

    1999-01-01

    Regional analyses of Amazon cattle pasture biogeochemistry are difficult due to the complexity of human, edaphic, biotic and climatic factors and persistent cloud cover in satellite observations. We developed a method to estimate key biophysical properties of Amazon pastures using hyperspectral reflectance data and photon transport inverse modeling. Remote estimates of live and senescent biomass were strongly correlated with plant-available forms of soil phosphorus and calcium. These results provide a basis for monitoring pasture condition and biogeochemistry in the Amazon Basin using spaceborne hyperspectral sensors.

  9. River Watch

    NSDL National Science Digital Library

    The National Weather Service of the National Oceanic and Atmospheric Administration (NOAA) has launched the River Watch site, providing up-to-date river forecast information for the nation's largest river basins: the Mississippi, Missouri, Illinois, and Ohio River Basins). Daily river level summaries are provided for each basin, in addition to five-day forecasts for river stage heights (in feet). This site also offers hyperlinks to river forecast sites for the other major regions of the US (Southern, Central, and Eastern Regions), and other related sites. For current information on river level conditions in the US, this is a top-notch resource, made more valuable by the geographical extent of its coverage.

  10. Morphodynamic evolution of an intertidal mudflat under the influence of Amazon sediment supply - Kourou mud bank, French Guiana, South America

    NASA Astrophysics Data System (ADS)

    Gensac, Erwan; Gardel, Antoine; Lesourd, Sandric; Brutier, Laurent

    2015-06-01

    The coastal environment between the Amazon and the Orinoco Rivers is characterised by the migration of large mud banks formed by accretion of the muddy discharge from the Amazon. The migration of mud in the shallow coastal waters is associated with the creation of mudflats that form a surface for the development of coastal mangroves after consolidation. This study focuses on the fine-scale sedimentary processes involved in the morphodynamic evolution of a consolidated mudflat and its erosion. Mudflats can be divided into two areas: the seafront and the inner part between the seafront and the land. This study highlights a link between tidal mud supply, biofilm migration and increasing elevation in the latter area. The migration of a biofilm through each cycle of tidal supply prevents erosion and permits the continuous accretion of the entire mudflat over several years. This increase in topography is also modulated by fortnightly tidal cycles. Desiccation greatly impacts the mudflat's structure at a yearly scale. This process plays an important role in the erosion of the seafront area under wave action by allowing the formation of mud pebbles, which are progressively abraded into fluid mud supplied to the inner part of the mudflat by over-wash processes. This study provides a better understanding of the behaviour of mudflats on the wave-exposed coast downdrift of the mouth of the Amazon by describing: (1) the processes involved in sediment exchanges between mudflats and mud banks, (2) the mechanisms associated with the persistence of mudflats along the French Guiana coast downdrift of the mouth of the Amazon, and (3) the processes involved in the erosion and recycling of these mudflats.

  11. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    ... of major cities are marked on the left-hand image; major rivers are marked on the right. The portion of the Mississippi River captured ... heavy rainfall swelled the Mississippi and Wisconsin rivers. In the early morning of April 25, two days before the right-hand image ...

  12. Merced River

    USGS Multimedia Gallery

    In this image, the Merced River can be seen just upstream of Happy Isles and the USGS Benchmark Streamgage in Yosemite National Park. The Merced River is a 145 mile (233 km) long tributary of the San Joaquin River. It drains a large section of the Sierra Nevadas, including Yosemite Valley....

  13. Elevated rates of gold mining in the Amazon revealed through high-resolution monitoring.

    PubMed

    Asner, Gregory P; Llactayo, William; Tupayachi, Raul; Luna, Ernesto Ráez

    2013-11-12

    Gold mining has rapidly increased in western Amazonia, but the rates and ecological impacts of mining remain poorly known and potentially underestimated. We combined field surveys, airborne mapping, and high-resolution satellite imaging to assess road- and river-based gold mining in the Madre de Dios region of the Peruvian Amazon from 1999 to 2012. In this period, the geographic extent of gold mining increased 400%. The average annual rate of forest loss as a result of gold mining tripled in 2008 following the global economic recession, closely associated with increased gold prices. Small clandestine operations now comprise more than half of all gold mining activities throughout the region. These rates of gold mining are far higher than previous estimates that were based on traditional satellite mapping techniques. Our results prove that gold mining is growing more rapidly than previously thought, and that high-resolution monitoring approaches are required to accurately quantify human impacts on tropical forests. PMID:24167281

  14. Elevated rates of gold mining in the Amazon revealed through high-resolution monitoring

    PubMed Central

    Asner, Gregory P.; Llactayo, William; Tupayachi, Raul; Luna, Ernesto Ráez

    2013-01-01

    Gold mining has rapidly increased in western Amazonia, but the rates and ecological impacts of mining remain poorly known and potentially underestimated. We combined field surveys, airborne mapping, and high-resolution satellite imaging to assess road- and river-based gold mining in the Madre de Dios region of the Peruvian Amazon from 1999 to 2012. In this period, the geographic extent of gold mining increased 400%. The average annual rate of forest loss as a result of gold mining tripled in 2008 following the global economic recession, closely associated with increased gold prices. Small clandestine operations now comprise more than half of all gold mining activities throughout the region. These rates of gold mining are far higher than previous estimates that were based on traditional satellite mapping techniques. Our results prove that gold mining is growing more rapidly than previously thought, and that high-resolution monitoring approaches are required to accurately quantify human impacts on tropical forests. PMID:24167281

  15. An Evaluation of Amazon’s Grid Computing Services: EC2 S3 and SQS

    Microsoft Academic Search

    Simson L. Garfinkel

    Abstract Amazon.com’s Elastic Compute Cloud (EC2), Simple Storage Service (S3) and Simple Queue Service (SQS) offer enterprise-class computing, storage and coordina- tion facilities to any organization or individual in the world with a valid credit card. This paper details our experience working with these commodity,grid comput- ing services between November 2006 and May 2007, including an analysis of the overall

  16. Cloning and immunoreactivity of the 5-HT1Mac and 5-HT2Mac receptors in the central nervous system of the freshwater prawn Macrobrachium rosenbergii

    PubMed Central

    Vázquez-Acevedo, Nietzell; Reyes-Colón, Dalynés; Ruíz-Rodríguez, Eduardo A.; Rivera, Nilsa M.; Rosenthal, Joshua; Kohn, Andrea B.; Moroz, Leonid L.; Sosa, María A.

    2009-01-01

    Biogenic amines are implicated in several mental disorders, many of which involve social interactions. Simple model systems, such as crustaceans, are often more amenable than vertebrates for studying mechanisms underlying behaviors. Although various cellular responses of biogenic amines have been characterized in crustaceans, the mechanisms linking these molecules to behavior remain largely unknown. Observed effects of serotonin receptor agonists and antagonists in abdomen posture, escape responses, and fighting have led to the suggestion that biogenic amine receptors may play a role in modulating interactive behaviors. As a first step in understanding this potential role of such receptors, we have cloned and fully sequenced two serotonin receptors, 5-HT1Mac and 5-HT2Mac, from the CNS of the freshwater prawn Macrobrachium rosenbergii, and have mapped their CNS immunohistochemical distribution. 5-HT1Mac was found primarily on the membranes of subsets of cells in all CNS ganglia, in fibers that traverse all CNS regions, and in the cytoplasm of a small number of cells in the brain, circum- and subesophageal ganglia (SEG), most of which also appear to contain dopamine. The pattern of 5-HT2Mac immunoreactivity was found to differ significantly, being found mostly in the central neuropil area of all ganglia, in glomeruli of the brain’s olfactory lobes, and in the cytoplasm of a small number of neurons in the SEG, thoracic and some abdominal ganglia. The observed differences in terms of localization, distribution within cells, and intensity of immunoreactive staining throughout the prawn’s CNS suggest that these receptors are likely to play different roles. PMID:19184976

  17. Landscape biogeochemistry reflected in shifting distributions of chemical traits in the Amazon forest canopy

    NASA Astrophysics Data System (ADS)

    Asner, Gregory P.; Anderson, Christopher B.; Martin, Roberta E.; Tupayachi, Raul; Knapp, David E.; Sinca, Felipe

    2015-07-01

    Tropical forest functional diversity, which is a measure of the diversity of organismal interactions with the environment, is poorly understood despite its importance for linking evolutionary biology to ecosystem biogeochemistry. Functional diversity is reflected in functional traits such as the concentrations of different compounds in leaves or the density of leaf mass, which are related to plant activities such as plant defence, nutrient cycling, or growth. In the Amazonian lowlands, river movement and microtopography control nutrient mobility, which may influence functional trait distributions. Here we use airborne laser-guided imaging spectroscopy to develop maps of 16 forest canopy traits, throughout four large landscapes that harbour three common forest community types on the Madre de Dios and Tambopata rivers in southwestern Amazonia. Our maps, which are based on quantitative chemometric analysis of forest canopies with visible-to-near infrared (400-2,500 nm) spectroscopy, reveal substantial variation in canopy traits and their distributions within and among forested landscapes. Forest canopy trait distributions are arranged in a nested pattern, with location along rivers controlling trait variation between different landscapes, and microtopography controlling trait variation within landscapes. We suggest that processes of nutrient deposition and depletion drive increasing phosphorus limitation, and a corresponding increase in plant defence, in an eastward direction from the base of the Andes into the Amazon Basin.

  18. Concentration and flux of suspended sediment on the Amazon continental shelf

    NASA Astrophysics Data System (ADS)

    Nittrouer, C. A.; Curtin, T. B.; DeMaster, D. J.

    The distribution and movement of suspended sediment has been examined on the continental shelf near the mouth of the Amazon River, during peak discharge of the river. Observations included: transmissometer/CTD profiles widely distributed on the shelf, and combined with current meter profiles at two anchor stations near the river mouth; drogue deployments northwest of the river mouth; and transmissometer/current meter moorings near the northern boundary (4°N) of the study area. Suspended-sediment concentration (SSC) becomes significant (10 mg l -1) landward of about the 30-m isobath, where it characteristically increases exponentially toward the seabed. A high SSC (generally 20 mgl -1 and often 100 mgl -1) is present in a turbid bottom layer which increases in thickness toward shore, probably as a result of shoaling surface waves and strong tidal currents. Landward of the 10-m isobath, a high SSC occupies most of the water column. On time scales less than a month, the predominant variations in SSC occur as a result of resuspension-deposition and of onshore-offshore advection associated with semidiurnal tides. Instantaneous fluxes of suspended sediment adjacent to the river mouth can exceed 50 g cm -1 s -1, and the net along-shelf flux (northwestward) associated with the North Brazilian Coastal Current may reach 3 g cm -1 s -1 between the 10- and 30-m isobaths. Estimates of annual sediment transport northwestward out of the study area, combined with estimates of sediment supply and accumulation, indicate that a much higher along-shelf flux must occur landward of the 10-m isobath and that coastal accretion is probably occurring.

  19. Amazonian Dark Earths: a case study in the Central Amazon

    E-print Network

    Rebellato, Lilian

    2011-12-31

    ......................................................................................... 108 Sample Preparation .................................................................... 108 Inductively Coupled Plasma–Mass Spectroscopy (ICP-MS) ...... 110 Mehlich 3... at Amazon Basin, Source IBGE ? Interactive Maps, Public Domain ..................................... 17 Figure 3 – Site location and study area...................................................................................................................... 100 Figure 4 – Map...

  20. Cropland expansion changes deforestation dynamics in the southern Brazilian Amazon

    E-print Network

    Camara, Gilberto

    Cropland expansion changes deforestation dynamics in the southern Brazilian Amazon Douglas C ranching or new deforestation has not been quantified and has major implications for future deforestation dynamics, carbon fluxes, forest fragmentation, and other ecosystem services. We combine deforestation maps

  1. Evaluating speech synthesis intelligibility using Amazon Mechanical Turk 

    E-print Network

    Wolters, Maria K.; Isaac, Karl B.; Renals, Steve

    2010-01-01

    Microtask platforms such as Amazon Mechanical Turk (AMT) are increasingly used to create speech and language resources. AMT in particular allows researchers to quickly recruit a large number of fairly demographically diverse ...

  2. Squamous cell carcinoma of the esophagus in an Amazon parrot.

    PubMed

    Murtaugh, R J; Ringler, D J; Petrak, M L

    1986-04-15

    Squamous cell carcinoma of the distal portion of the esophagus was diagnosed, through use of contrast radiography and necropsy, in a 30-year-old Amazon parrot. The clinical signs were collapse, opisthotonos, and torticollis following feeding. PMID:3710880

  3. A new metric to help understand Amazon rainforest precipitation

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-09-01

    In the Amazon rainforest, the chain of events that turns a small-scale process like a localized increase in evaporation into a towering storm cloud is long and twisted. To understand the complex dynamics that lead to precipitation and to identify the relative importance of various processes, researchers need uninterrupted observations at high-resolution time scales over many years. Such observations have traditionally been scarce for tropical continental environments, such as the Amazon, where logistics are difficult.

  4. Sensitivity of the Amazon rainforest to convective storms

    NASA Astrophysics Data System (ADS)

    Negron Juarez, R. I.; Chambers, J. Q.; Rifai, S. W.; Urquiza Munoz, J. D.; Tello, R.; Alegria Munoz, W.; Marra, D.; Ribeiro, G.; Higuchi, N.

    2012-12-01

    The Amazon rainforest is the largest contiguous continental tropical forest in the world and is a world center of carbon storage, biodiversity, biogeochemical cycles and biogeophysical processes that affect the Earth climate system. Yet anthropogenic activities have produced changes in the forest-climate system. Consequently, an increase in rainfall in both the Western and Central Amazon and a decrease in the Eastern Amazon are expected due to these anthropogenic activities. While the projected decrease in rainfall has been discussed under the context of drought, deforestation, and fires, the effect of an increase in rainfall, and associated convective processes, on forest ecosystems has been overlooked. Across the Amazon rainforest, Western Amazonia has the highest precipitation rates, wood productivity, soil fertility, recruitment and mortality rates. Yet our field-measured tree mortality data from blowdowns that occurred in Western and Central Amazonia do not show a statistical difference in tree mortality between these regions. However, downburst velocities associated with these disturbances were calculated to be lower in Western Amazonia than in the Central Amazon. This suggests the Western Amazon is more highly sensitive to intense convective systems. This result is particularly relevant given the expected increase in rainfall in the Western and Central Amazon. The increase in rainfall is associated with more intense convective systems that in turn imply an increase in low level jet stream (LLJ) intensity east of the Andes. The presence of the LLJ is the main cause of squall lines and an increase in LLJ intensity will therefore cause increased propagation of squall lines into the Amazon basin. More frequent and active squall lines have the potential to increase the intensity and frequency of downbursts responsible for large forest blowdowns that will affect the biogeophysical feedbacks on the forest ecosystem and carbon budget.

  5. Highways and outposts: economic development and health threats in the central Brazilian Amazon region

    PubMed Central

    2010-01-01

    Background Economic development is often evoked as a driving force that has the capacity to improve the social and health conditions of remote areas. However, development projects produce uneven impacts on local communities, according to their different positions within society. This study examines the spatial distribution of three major health threats in the Brazilian Amazon region that may undergo changes through highway construction. Homicide mortality, AIDS incidence and malaria prevalence rates were calculated for 70 municipalities located within the areas of influence of the Cuiabá-Santarém highway (BR-163), i.e. in the western part of the state of Pará state and the northern part of Mato Grosso. Results The municipalities were characterized using social and economic indicators such as gross domestic product (GDP), urban and indigenous populations, and recent migration. The municipalities' connections to the region's main transportation routes (BR-163 and Trans-Amazonian highways, along with the Amazon and Tapajós rivers) were identified by tagging the municipalities that have boundaries crossing these routes, using GIS overlay operations. Multiple regression was used to identify the major driving forces and constraints relating to the distribution of health threats. The main explanatory variables for higher malaria prevalence were: proximity to the Trans-Amazonian highway, high proportion of indigenous population and low proportion of migrants. High homicide rates were associated with high proportions of migrants, while connection to the Amazon River played a protective role. AIDS incidence was higher in municipalities with recent increases in GDP and high proportions of urban population. Conclusions Highways induce social and environmental changes and play different roles in spreading and maintaining diseases and health threats. The most remote areas are still protected against violence but are vulnerable to malaria. Rapid economic and demographic growth increases the risk of AIDS transmission and violence. Highways connect secluded localities and may threaten local populations. This region has been undergoing rapid localized development booms, thus creating outposts of rapid and temporary migration, which may introduce health risks to remote areas. PMID:20553625

  6. Surface Water Dynamics in the Amazon Basin: Application of Satellite Radar Altimetry

    NASA Astrophysics Data System (ADS)

    Birkett, C.; Mertes, L.; Dunne, T.; Costa, M.; Jasinski, M.

    2003-04-01

    Satellite radar altimetry has the ability to monitor variations in surface water height (stage) for large wetlands, rivers, and associated floodplains. A clear advantage is the provision of data where traditional gauges are absent. As part of an international program a complete altimetric analysis of the Amazon Basin is being undertaken. Here, an updated and more rigorous evaluation of the TOPEX/POSEIDON (T/P) dataset is presented for the first ~7.5 years of the mission. With an initial study group of 230 targets, height variability at many ungauged locations can be observed for 30-50%, the range reflecting the clarity of the variations in lieu of instrument limitations. An assessment of the instrument performance confirms that the minimum river width attainable is ~1 km in the presence of some inundated floodplain. This constraint does allow observation of the main stem (Solimões/Amazon) and the larger tributaries, but rugged terrain in the vicinity of the target additionally places severe limitations on data retrieval. First-order validation exercises with the deduced 1992-1999 time series of stage fluctuations reveal accuracies ranging from tens of centimeters to several metres (mean ~1.1 m rms). Altimetric water levels in the Solimões and Amazon are particularly well defined with amplitudes <13 m and variations in peak level timing from May to July. The water-surface gradient of the main stem is found to vary both spatially and temporally, with values ranging from 1.5 cm/km downstream, to 4.0 cm/km for more upstream reaches. In agreement with ground-based estimates, the seasonal variability of the gradients reveals that the hysteresis characteristic of the flood wave varies along the main stem and the derived altimetric velocity of this flood wave is estimated to be ~0.35 m/s. Overall, the altimetric results demonstrate that the T/P mission is successfully monitoring the transient flood waves of this continental-scale basin.

  7. Smoking Rain Clouds over the Amazon

    NASA Astrophysics Data System (ADS)

    Andreae, M. O.; Rosenfeld, D.; Artaxo, P.; Costa, A. A.; Frank, G. P.; Longo, K. M.; Silva-Dias, M. A. F.

    2004-02-01

    Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation from 1.5 kilometers above cloud base in pristine clouds to more than 5 kilometers in polluted clouds and more than 7 kilometers in pyro-clouds. Suppression of low-level rainout and aerosol washout allows transport of water and smoke to upper levels, where the clouds appear ``smoking'' as they detrain much of the pollution. Elevating the onset of precipitation allows invigoration of the updrafts, causing intense thunderstorms, large hail, and greater likelihood for overshooting cloud tops into the stratosphere. There, detrained pollutants and water vapor would have profound radiative impacts on the climate system. The invigorated storms release the latent heat higher in the atmosphere. This should substantially affect the regional and global circulation systems. Together, these processes affect the water cycle, the pollution burden of the atmosphere, and the dynamics of atmospheric circulation.

  8. Smoking rain clouds over the Amazon.

    PubMed

    Andreae, M O; Rosenfeld, D; Artaxo, P; Costa, A A; Frank, G P; Longo, K M; Silva-Dias, M A F

    2004-02-27

    Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation from 1.5 kilometers above cloud base in pristine clouds to more than 5 kilometers in polluted clouds and more than 7 kilometers in pyro-clouds. Suppression of low-level rainout and aerosol washout allows transport of water and smoke to upper levels, where the clouds appear "smoking" as they detrain much of the pollution. Elevating the onset of precipitation allows invigoration of the updrafts, causing intense thunderstorms, large hail, and greater likelihood for overshooting cloud tops into the stratosphere. There, detrained pollutants and water vapor would have profound radiative impacts on the climate system. The invigorated storms release the latent heat higher in the atmosphere. This should substantially affect the regional and global circulation systems. Together, these processes affect the water cycle, the pollution burden of the atmosphere, and the dynamics of atmospheric circulation. PMID:14988556

  9. Holocene fires in the northern Amazon basin

    NASA Astrophysics Data System (ADS)

    Saldarriaga, Juan G.; West, Darrell C.

    1986-11-01

    The ubiquitous occurrence of charcoal in the forest soils of the Upper Rio Negro region of Colombia and Venezuela indicates the presence of frequent and widespread fires in the Amazon Basin, possibly associated with extremely dry periods or human disturbances. Charcoal ranged from 3.12 to 24.76 mg/cm 3 in the upper 50 cm of soil and was more abundant in Oxisols and Ultisols than in other soil types. Charcoal dates range from 6260 yr B.P. to the present. Several dates coincide with dry phases recorded during the Holocene. Ceramic shards were found at several sites, and thermoluminescence analysis indicates that their ages range from 3750 to 460 yr B.P. The age of charcoal and shards confirms that this region has been subjected to fire and human disturbances during the past 6000 yr.

  10. Dimethyl sulfide in the Amazon rain forest

    NASA Astrophysics Data System (ADS)

    Jardine, K.; Yañez-Serrano, A. M.; Williams, J.; Kunert, N.; Jardine, A.; Taylor, T.; Abrell, L.; Artaxo, P.; Guenther, A.; Hewitt, C. N.; House, E.; Florentino, A. P.; Manzi, A.; Higuchi, N.; Kesselmeier, J.; Behrendt, T.; Veres, P. R.; Derstroff, B.; Fuentes, J. D.; Martin, S. T.; Andreae, M. O.

    2015-01-01

    Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified ambient DMS mixing ratios within and above a primary rainforest ecosystem in the central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-2014). Elevated but highly variable DMS mixing ratios were observed within the canopy, showing clear evidence of a net ecosystem source to the atmosphere during both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios lasting up to 8 h (up to 160 parts per trillion (ppt)) often occurred within the canopy and near the surface during many evenings and nights. Daytime gradients showed mixing ratios (up to 80 ppt) peaking near the top of the canopy as well as near the ground following a rain event. The spatial and temporal distribution of DMS suggests that ambient levels and their potential climatic impacts are dominated by local soil and plant emissions. A soil source was confirmed by measurements of DMS emission fluxes from Amazon soils as a function of temperature and soil moisture. Furthermore, light- and temperature-dependent DMS emissions were measured from seven tropical tree species. Our study has important implications for understanding terrestrial DMS sources and their role in coupled land-atmosphere climate feedbacks.

  11. Dimethyl sulfide in the Amazon rain forest

    SciTech Connect

    Jardine, Kolby; Yanez-Serrano, A. M.; Williams, J.; Kunert, N.; Jardine, A.; Taylor, T.; Abrell, L.; Artaxo, Paulo; Guenther, Alex B.; Hewitt, C. N.; House, E.; Florentino, A. P.; Manzi, A.; Higuchi, N.; Kesselmeier, J.; Behrendt, T.; Veres, P. R.; Derstroff, B.; Fuentes, J.; Martin, Scot T.; Andreae, M. O.

    2015-01-01

    Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate 44 through the formation of gaseous sulfuric acid, which can yield secondary sulfate 45 aerosols and contribute to new particle formation. While oceans are generally 46 considered the dominant source of DMS, a shortage of ecosystem observations prevents 47 an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified 48 ambient DMS mixing ratios within and above a primary rainforest ecosystem in the 49 central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-50 2014). Elevated but highly variable DMS mixing ratios were observed within the 51 canopy, showing clear evidence of a net ecosystem source to the atmosphere during 52 both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios 53 lasting up to 8 hours (up to 160 ppt) often occurred within the canopy and near the 54 surface during many evenings and nights. Daytime gradients showed mixing ratios (up 55 to 80 ppt) peaking near the top of the canopy as well as near the ground following a rain 56 event. The spatial and temporal distribution of DMS suggests that ambient levels and 57 their potential climatic impacts are dominated by local soil and plant emissions. A soil 58 source was confirmed by measurements of DMS emission fluxes from Amazon soils as 59 a function of temperature and soil moisture. Furthermore, light and temperature 60 dependent DMS emissions were measured from seven tropical tree species. Our study 61 has important implications for understanding terrestrial DMS sources and their role in 62 coupled land-atmosphere climate feedbacks. 63

  12. Highly dynamic sediment deposition in modern times on the submarine Amazon Delta - First results from the AMADEUS project (Cruise MSM 20/3, February/March 2012)

    NASA Astrophysics Data System (ADS)

    Schwenk, T.; Mulitza, S.; Chiessi, C.; Haberkern, J.; Wiers, S.

    2012-12-01

    The submarine Amazon Delta is the major sink for the enormous sediment load of the Amazon River during modern times. Supported by its large drainage area (7 M km2) and the huge total run-off of 6300 km3/yr, which is 20% of the global run-off into the oceans, the Amazon River discharges the worldwide highest total sediment load to the oceans, namely 1200 Mt/yr. Characterized by sedimentation rates of decimeters per year, the submarine Amazon Delta can act as an ultra-high resolution archive of the Anthropocene climatic history of the Amazon basin. However, it has to be kept in mind that the accumulation on the delta is controlled by an interaction of sediment supply and the shelf current pattern including strong tides. To study in general the response of Amazon sedimentation to deforestation, land use and climate variability, the Project AMADEUS has been established in cooperation between the MARUM, Bremen, Germany and the University of Sao Paulo, Brazil. Within this project a first cruise was carried out with the RV Maria S. Merian in February/March 2012 in order to collect high-resolution seismic data (Mini GI Gun, 50 m analogue streamer), sediment echosounder data (Parasound; 4 kHz, 18 kHz, 40 kHz), swath-sounder data (bathymetry and backscatter), sediment samples and water column samples in front of the Amazon River mouth. The presentation will focus mainly on the seismo-acoustic data sets. As a first step, the data were analyzed to understand the internal architecture of the recent clinoform build-up in time and space. The main emphasis were set on the foreset and bottomset, where most of the accretion occur, to allow volume and sediment budget calculations in relation to the denudation history of the Amazon basin. Especially the Parasound data reveal significant changes of the clinoform along the delta front in terms of thickness, slope angle, shape (oblique-sigmoidal-convex) and internal architecture (especially depths and character of erosional unconformities). A special outcome of the new data is the comparison with Parasound data collected in 1996 during RV Meteor Cruise M34/4. Due to several crossing points of both data sets and even a repetition of a profile shot in 1996 it is now possible to carry out direct measurements of the accumulation during the last 16 years. It turned out, that up to 6 m of sediments has been deposited at some locations since 1996, and that the progradation of the delta was around 50 m/yrs, pointing probably to a strong modern denudation in the Amazon Basin. Moreover, it is visible that the style of the clinoform changed slightly within the last 16 years indicating a change of deposition and transport processes during this time. Using the derived sedimentation rate it will be possible to date the identified erosional unonformities which represents obviously drastic changes in the transport and/or current regime. By utilizing the reflector representing the sefloor from 1996 and the unconformities as key horizons, the seismo-stratigraphic analysis in combination with coring results will be continued to enable finally a calculation of sediment budgets on yearly, decadal and centennial scales.

  13. Molecular profiles and pathogen-induced transcriptional responses of prawn B cell lymphoma-2 related ovarian killer protein (BOK).

    PubMed

    Chaurasia, Mukesh Kumar; Palanisamy, Rajesh; Harikrishnan, Ramasamy; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Arockiaraj, Jesu

    2015-08-01

    In this study, we have reported a molecular characterization of the first B cell lymphoma-2 (BCL-2) related ovarian killer protein (BOK) from freshwater prawn Macrobrachium rosenbergii (Mr). BOK is a novel pro-apoptotic protein of the BCL-2 family that entails in mediating apoptosis to remove cancer cells. A cDNA sequence of MrBOK was identified from the prawn cDNA library and its full length was obtained by internal sequencing. The coding region of MrBOK yields a polypeptide of 291 amino acids. The analysis revealed that MrBOK contains a transmembrane helix at V(261)-L(283) and a putative BCL-2 family domain at V(144)-W(245). MrBOK also possessed four putative BCL-2 homology domains including BH1, BH2, BH3 and weak BH4. The BH3 contains 21 binding sites and among them five residues are highly conserved with the aligned BOK proteins. The homology analysis showed that MrBOK shared maximum similarity with the Caligus rogercresseyi BOK A. The topology of the phylogenetic tree was classified into nine sister groups which includes BOK, BAK, BAX, BAD, BCL-2, BCL-XL, NR13 and MCL members. The BOK protein group further sub-grouped into vertebrate and invertebrate BOK, wherein MrBOK located within insect monophyletic clad of invertebrate BOK. The secondary structural analysis showed that MrBOK contains 11 ?-helices (52.2%) which are connected over random coils (47.7%). The 3D structure of MrBOK showed three central helices (?6, ?7 and ?8) which formed the core of the protein and are flanked on one side by ?1, ?2 and ?3, and on the other side by ?4, ?5 and ?11. MrBOK mRNA is expressed most abundantly (P < 0.05) in ovary compared to other tissues taken for analysis. Hence ovary was selected to study the possible roles of MrBOK mRNA regulation upon bacterial (Aeromonas hydrophila and Vibrio harveyi) and viral [white spot syndrome virus (WSSV) and M. rosenbergii nodovirus] infection. During bacterial and viral infection, the highest MrBOK mRNA transcription was varied at different time points. In bacterial infected ovary tissue, the highest mRNA expression was at 24 h post-infection, whereas in viral infection, the expression was highest at 48 h post-infection. Thus we can conclude that MrBOK functions as an apoptotic protein in intracellular programmed cell-death pathway to counteract the anti-apoptotic proteins released by bacterial and viral pathogens at the time of infection. This is the first study that emphasizes the importance of BOK during bacterial and viral infection in crustacean. PMID:25982403

  14. Characterization of two novel ADP ribosylation factors from giant freshwater prawn Macrobrachium rosenbergii and their responses to WSSV challenge.

    PubMed

    Ding, Zheng-Feng; Ren, Jie; Tan, Jing-Min; Wang, Zheng; Yin, Shao-Wu; Huang, Ying; Huang, Xin; Wang, Wen; Lan, Jiang-Feng; Ren, Qian

    2015-01-01

    ADP-ribosylation factors (Arfs) are small GTP-binding proteins that have an essential function in intracellular trafficking and organelle structure. To date, little information is available on the Arfs in the economically important giant freshwater prawn Macrobrachium rosenbergii and their relationship to viral infection. Here we identified two Arf genes from M.?rosenbergii (MrArf1 and MrArf2) for the first time. Phylogenetic analysis showed that MrArf1, together with MjArf1 from shrimp Marsupenaeus japonicus belonged to Class I Arfs. By contrast, MrArf2 didn't not match any of the Arfs classes of I/II/III, although it could be clustered with an Arf protein from M.?japonicas called MjArfn, which may represent an analog of the Arf. MrArf1 was ubiquitously expressed in all the examined tissues, with the highest transcription level in the hepatopancreas, whereas MrArf2 was only highly expressed in the hepatopancreas and exhibited very low levels in the heart, stomach, gills and intestine. The expression level of MrArf1 in the gills was down-regulated post 24?h WSSV challenge, and reached the maximal level at 48?h. MrArf1 in the hepatopancreas went up from 24 to 48?h WSSV challenge. MrArf2 transcript in the gill also went down at 24?h and then was upregulated at 48?h WSSV challenge. MrArf2 increased significantly in the hepatopancreas 24?h after infection and then went down at 48?h WSSV challenge. RNAi results showed that knockdown of MrArf1 or MrArf2 could inhibit the expression of the envelope protein gene vp28 of the WSSV. So, it could be speculated that MrArf1 and MrArf2 might play important roles in the innate immune system against WSSV infection. PMID:25451300

  15. Characterization of a prawn OA/TA receptor in Xenopus oocytes suggests functional selectivity between octopamine and tyramine.

    PubMed

    Jezzini, Sami H; Reyes-Colón, Dalynés; Sosa, María A

    2014-01-01

    Here we report the characterization of an octopamine/tyramine (OA/TA or TyrR1) receptor (OA/TAMac) cloned from the freshwater prawn, Macrobrachium rosenbergii, an animal used in the study of agonistic social behavior. The invertebrate OA/TA receptors are seven trans-membrane domain G-protein coupled receptors that are related to vertebrate adrenergic receptors. Behavioral studies in arthropods indicate that octopaminergic signaling systems modulate fight or flight behaviors with octopamine and/or tyramine functioning in a similar way to the adrenalins in vertebrate systems. Despite the importance of octopamine signaling in behavioral studies of decapod crustaceans there are no functional data available for any of their octopamine or tyramine receptors. We expressed OA/TAMac in Xenopus oocytes where agonist-evoked trans-membrane currents were used as readouts of receptor activity. The currents were most effectively evoked by tyramine but were also evoked by octopamine and dopamine. They were effectively blocked by yohimbine. The electrophysiological approach we used enabled the continuous observation of complex dynamics over time. Using voltage steps, we were able to simultaneously resolve two types of endogenous currents that are affected over different time scales. At higher concentrations we observe that octopamine and tyramine can produce different and opposing effects on both of these currents, presumably through the activity of the single expressed receptor type. The pharmacological profile and apparent functional-selectivity are consistent with properties first observed in the OA/TA receptor from the insect Drosophila melanogaster. As the first functional data reported for any crustacean OA/TA receptor, these results suggest that functional-selectivity between tyramine and octopamine is a feature of this receptor type that may be conserved among arthropods. PMID:25350749

  16. Cathepsin C transcripts are differentially expressed in the final stages of oocyte maturation in kuruma prawn Marsupenaeus japonicus.

    PubMed

    Qiu, Gao-Feng; Yamano, Keisuke; Unuma, Tatsuya

    2005-02-01

    To elucidate the molecular mechanism of oocyte maturation in the kuruma prawn (Marsupenaeus japonicus), subtractive suppression hybridization (SSH) was initially used to identify novel up-regulated genes during the final stages of oocyte maturation, followed by evaluation of the differential expression profile by macroarray and quantitative real-time RT-PCR analyses. The cathepsin C (dipeptidyl peptidase I) gene was thus found to exhibit a significantly higher expression around the onset of cortical rod (CR) formation (early CR stage, appearance of round CRs), progress to a higher mRNA level until the middle CR stage (elongation of CRs), then rapidly revert to a low expression level at the late CR stage (occurrence of germinal vesicle breakdown, GVBD), as also observed at the non-CR stage (previtellogenesis and vitellogenesis). In situ hybridization analyses revealed that the sites of the expression of cathepsin C transcripts in the ovary were distributed in both oocyte and follicle cells, particularly at the early CR stage. A full-length cDNA sequence of this stage-specific gene was subsequently determined by rapid amplification of the cDNA 3' and 5' ends (3' and 5' RACE). The deduced amino acid sequence of the 230-residue mature peptide shared 67-70% identity to the known cathepsin C in mammals. Western blot analysis showed that expression of procathepsin C protein was exclusively at CR stages. The storage site of procathepsin C protein was localized in CRs as revealed by immunohistochemical analysis. This is the first report on the full-length cDNA sequence of cathepsin C and a demonstration of its involvement in the final stages of oocyte maturation in crustacean species. PMID:15649764

  17. Function of an anti-lipopolysaccharide factor (ALF) isoform isolated from the hemocytes of the giant freshwater prawn Macrobrachium rosenbergii in protecting against bacterial infection.

    PubMed

    Liu, Chia-Chen; Chung, Chien-Pang; Lin, Chang-Yi; Sung, Hung-Hung

    2014-02-01

    In this study, a 780-bp full-length cDNA encoding Macrobrachium rosenbergii anti-lipopolysaccharide factor (MrALF) from hemocytes was cloned and identified. The ALF isoform exhibited immune activities, and its concentration in hemolymph was determined. An in vivo expression study showed that the ALF mRNA level of hemocytes could be induced by lipopolysaccharides (LPSs) in an exposure time-dependent manner. Purified recombinant MrALF (rMrALF) expressed in the yeast Pichia pastoris SMD1168 eukaryotic protein expression system demonstrated antibacterial activity against the Gram-negative prawn pathogen Aeromonas hydrophila (minimum inhibitory concentration (MIC)=0.806?M, minimum bactericidal concentration (MBC)=1.606?M) but not the Gram-positive pathogen Lactococcus garvieae exposed to 25.696?M of rALF. However, rMrALF can bind to Gram-negative and -positive bacteria. An in vivo expression study demonstrated that the ALF concentrations in prawn hemocytes and plasma were 0.176?M and 0.168?M, respectively; following LPS treatment for 6h, the corresponding concentrations were 0.133?M in hemocytes and 0.272?M in plasma. Furthermore, the percentage of hemocytes phagocytosing bacteria cells was higher in hemoyctes previously treated with MrALF than those treated with sterile medium. These results suggest that in the innate immune response of M. rosenbergii, the MrALF from hemocytes may play an opsonin during a bacterial invasion. PMID:24333685

  18. IgE Reactivity of Blue Swimmer Crab (Portunus pelagicus) Tropomyosin, Por p 1, and Other Allergens; Cross-Reactivity with Black Tiger Prawn and Effects of Heating

    PubMed Central

    Varese, Nirupama; Zubrinich, Celia; Lopata, Andreas L.; O'Hehir, Robyn E.; Rolland, Jennifer M.

    2013-01-01

    Shellfish allergy is a major cause of food-induced anaphylaxis, but the allergens are not well characterized. This study examined the effects of heating on blue swimmer crab (Portunus pelagicus) allergens in comparison with those of black tiger prawn (Penaeus monodon) by testing reactivity with shellfish-allergic subjects' serum IgE. Cooked extracts of both species showed markedly increased IgE reactivity by ELISA and immunoblotting, and clinical relevance of IgE reactivity was confirmed by basophil activation tests. Inhibition IgE ELISA and immunoblotting demonstrated cross-reactivity between the crab and prawn extracts, predominantly due to tropomyosin, but crab-specific IgE-reactivity was also observed. The major blue swimmer crab allergen tropomyosin, Por p 1, was cloned and sequenced, showing strong homology with tropomyosin of other crustacean species but also sequence variation within known and predicted linear IgE epitopes. These findings will advance more reliable diagnosis and management of potentially severe food allergy due to crustaceans. PMID:23840718

  19. Des Lacs River and Souris River

    USGS Multimedia Gallery

     The Des Lacs River coming in to the Souris River. Des Lacs River is the darker water, which is sediment and the Souris River is the lighter water. >Photo taken by USGS personnel on a Civil Air Patrol flight....

  20. Vegetation Study of Amazon using QSCAT in comparison with SASS, ESCAT and NSCAT

    E-print Network

    Long, David G.

    in the Amazon basin. The three sites are representatives of dense vegetation from central amazon rain forest during the last few decades due to accelerated logging and other anthropogenic influences. Amazon forest) algorithm [l].The SIR algorithm exploits the high tempo- ral resolution of scatterometer data to improve

  1. Oil and Gas Projects in the Western Amazon: Threats to Wilderness, Biodiversity, and Indigenous Peoples

    Microsoft Academic Search

    Matt Finer; Clinton N. Jenkins; Stuart L. Pimm; Brian Keane; Carl Ross

    2008-01-01

    Background: The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many

  2. Oil and Gas Projects in the Western Amazon: Threats to Wilderness, Biodiversity, and Indigenous Peoples

    Microsoft Academic Search

    Matt Finer; Clinton N. Jenkins; Stuart L. Pimm; Brian Keane; Carl Ross; Dennis Marinus Hansen

    2008-01-01

    BackgroundThe western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many yet

  3. Carbon Emissions from Deforestation in the Brazilian Amazon Region

    NASA Technical Reports Server (NTRS)

    Potter, C.; Klooster, S.; Genovese, V.

    2009-01-01

    A simulation model based on satellite observations of monthly vegetation greenness from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2002. The NASA-CASA (Carnegie Ames Stanford Approach) model estimates of annual forest production were used for the first time as the basis to generate a prediction for the standing pool of carbon in above-ground biomass (AGB; gC/sq m) for forested areas of the Brazilian Amazon region. Plot-level measurements of the residence time of carbon in wood in Amazon forest from Malhi et al. (2006) were interpolated by inverse distance weighting algorithms and used with CASA to generate a new regional map of AGB. Data from the Brazilian PRODES (Estimativa do Desflorestamento da Amazonia) project were used to map deforested areas. Results show that net primary production (NPP) sinks for carbon varied between 4.25 Pg C/yr (1 Pg=10(exp 15)g) and 4.34 Pg C for the region and were highest across the eastern and northern Amazon areas, whereas deforestation sources of CO2 flux from decomposition of residual woody debris were higher and less seasonal in the central Amazon than in the eastern and southern areas. Increased woody debris from past deforestation events was predicted to alter the net ecosystem carbon balance of the Amazon region to generate annual CO2 source fluxes at least two times higher than previously predicted by CASA modeling studies. Variations in climate, land cover, and forest burning were predicted to release carbon at rates of 0.5 to 1 Pg C/yr from the Brazilian Amazon. When direct deforestation emissions of CO2 from forest burning of between 0.2 and 0.6 Pg C/yr in the Legal Amazon are overlooked in regional budgets, the year-to-year variations in this net biome flux may appear to be large, whereas our model results implies net biome fluxes had actually been relatively consistent from year to year during the period 2000-2002. This is the first study to use MODIS data to model all carbon pools (wood, leaf, root) dynamically in simulations of Amazon forest deforestation from clearing and burning of all kinds.

  4. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    ... rainfalls on the Upper Mississippi River area of Minnesota, Wisconsin, Iowa and Illinois. In the images above, the Mississippi travels ... from upper left to lower right from approximately La Crosse, Wisconsin to Davenport, Iowa. The Wisconsin River travels diagonally from the ...

  5. Spatial Distribution of Carbon Stock in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Saatchi, S. S.; Houghton, R. A.; Dos Santos Alvala, R. C.; Soares, J. V.; Yu, Y.

    2005-12-01

    The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we introduce a methodology based on spatial data, such as land cover, remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 forest plots distributed over the basin. Results show that AGLB is highest in the main Central Amazon and in regions to the east and north, including the Guyanas. Biomass is generally above 300 Mg/ha here except in areas of intense logging or open floodplains. In the Western Amazon from the lowland regions of Peru, Ecuador, and Colombia to the Andean elevational gradients, biomass ranges from 150-300 Mg/ha. Most transitional and seasonal forests in southern and northwestern edges of the basin have biomass ranging from 100-200 Mg/ha. We predict, the total carbon in forest biomass of the Amazon basin, including the dead and belowground biomass, is about 86 PgC with uncertainty that compares in magnitude with the range of carbon predicted by other models.

  6. Evidence for the control of river-water chemical stratification on the geochemistry of Amazonian floodplain sediments

    NASA Astrophysics Data System (ADS)

    Roddaz, Martin; Viers, Jérôme; Moreira-Turcq, Patricia; Blondel, Camille; Sontag, Francis; Guyot, Jean-Loup; Moreira, Luciane

    2014-05-01

    Holocene and historical Amazonian floodplain deposits collected from two cores of the Varzea Curuai flooded area (Brazil) were analysed for major and trace element geochemistry as well as Nd-Sr isotopic compositions (21 samples). The TA11 and TA14 cores (110 cm and 270 cm in depth, respectively) were collected at different locations in the varzea, near a channel inlet connecting the Amazon River to the varzea and at the centre of the varzea, respectively. The two cores represent records of sedimentation on different time-scales, with TA11 covering the last 100 years and TA14 extending back to 5600 years cal BP. Although the sediments are generally coarser in TA11 than in TA14, the major and trace element concentrations, Cr/Th and Th/Sc and Eu anomalies and Nd-Sr isotopic compositions in both cores fail to show any clear variations with depth. However, there are some chemical differences between the two analysed cores. The TA14 sediments have higher Al/Si and CIA values than those of TA11. The TA14 sediments are enriched in Th, U, Y, Nb, REE, Cs, Rb, V and Ni but show slightly depleted MgO, CaO and Sr and more strongly depleted Na2O, Zr and Hf compared with TA11. In addition, the Nd-Sr isotopic compositions of the TA11 sediment core are on the whole similar to the Solimões suspended particulate matter (SPM), whereas TA14 has a similar Nd-Sr isotopic composition compared with the SPM of the Amazon River at Obidos. These differences are best explained by chemical stratification of the Amazon River. During flooding of the Amazon River, coarser grained particulates supplied by the Solimões River are deposited in the deepest environments near the channel inlet, as recorded in the TA11 sediment core. By contrast, finer grained suspended sediments derived from the Madeira River are transported into the shallower environments of the varzea system and deposited as a result of flow expansion and loss of carrying power, as recorded in the TA14 sediment core. We calculate that between ~43 and ~85% of the sediment input to the TA14 core site are derived from the Madeira River, while all the sediment in the TA11 core sample is supplied by the Solimões River. Finally, our findings lead us to question whether major rivers are chemically stratified and to what extent the Amazon River is representative of major rivers both at the present-day and in the geological past.

  7. Geographical genetics of Pseudoplatystoma punctifer (Castelnau, 1855) (Siluriformes, Pimelodidae) in the Amazon Basin.

    PubMed

    Telles, M P C; Collevatti, R G; Braga, R S; Guedes, L B S; Castro, T G; Costa, M C; Silva-Júnior, N J; Barthem, R B; Diniz-Filho, J A F

    2014-01-01

    Geographical genetics allows the evaluation of evolutionary processes underlying genetic variation within and among local populations and forms the basis for establishing more effective strategies for biodiversity conservation at the population level. In this study, we used explicit spatial analyses to investigate molecular genetic variation (estimated using 7 microsatellite markers) of Pseudoplatystoma punctifer, by using samples obtained from 15 localities along the Madeira River and Solimões, Amazon Basin. A high genetic diversity was observed associated with a relatively low FST (0.057; P < 0.001), but pairwise FST values ranged from zero up to 0.21 when some pairs of populations were compared. These FST values have a relatively low correlation with geographic distances (r = 0.343; P = 0.074 by Mantel test), but a Mantel correlogram revealed that close populations (up to 80 km) tended to be more similar than expected by chance (r = 0.360; P = 0.015). The correlogram also showed a exponential-like decrease of genetic similarity with distance, with a patch-size of around 200 km, compatible with isolation-by-distance and analogous processes related to local constraints of dispersal and spatially structured levels of gene flow. The pattern revealed herein has important implications for establishing strategies to maintain genetic diversity in the species, especially considering the threats due to human impacts caused by building large dams in this river system. PMID:24854445

  8. Carbon Tetrachloride Emissions from the Amazon Forest

    NASA Astrophysics Data System (ADS)

    Jardine, K.; Chambers, J. Q.; Higuchi, N.; Jardine, A. B.; Martin, S. T.; Manzi, A. O.

    2014-12-01

    As a chemically inert greenhouse gas in the troposphere with lifetimes up to 50 years but active in ozone destruction in the stratosphere, carbon tetrachloride (CCl4) plays a major role in the atmospheric chlorine budget and is widely considered strictly of anthropogenic origin deriving from numerous industrial processes and products. However, satellite remote sensing studies have shown higher concentrations at the Equator, and earlier work has suggested possible biogenic sources. Here we present highly vertically-resolved atmospheric gradients of CCl4 within and above a primary rainforest ecosystem from three towers in the Central Amazon. The observed buildup of CCl4 mixing ratios near the top of the main canopies provides new evidence for a potentially large biogenic source from the Basin. By demonstrating the need to represent tropical forests as biogenic sources of CCl4, our study may help narrow the gap between remote sensing observations of CCl4 and emission, chemistry, and transport models and therefore lead to improved predictions of its role in atmospheric chemistry and climate.

  9. Climate extremes in the amazon basin

    NASA Astrophysics Data System (ADS)

    Marengo, José; Mendes, David

    2010-05-01

    Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate (CCSP, 2008). Indeed, according to IPCC AR4, confidence has increased that some extremes will become more frequent, more widespread and/or more intense during the 21st century . Until recently, there had been little published work on rainfall extremes in South America, and emphasis has been given to the La Plata Basin, where data coverage is much better. In this study, we use the indices of extremes derived by the WMO and used for the IPCC AR4 applied to 100 stations in Amazon Basin for the period from 1971 to 2005, with focus on rainfall extremes. The quality control involved carefully evaluating numerous detailed graphs of daily data to detect evidence of possible quality issues with the data as well as statistically identifying outliers. Each outlier or potential data problem was manually validated using metadata information of our climate data.

  10. Conducting behavioral research on Amazon's Mechanical Turk.

    PubMed

    Mason, Winter; Suri, Siddharth

    2012-03-01

    Amazon's Mechanical Turk is an online labor market where requesters post jobs and workers choose which jobs to do for pay. The central purpose of this article is to demonstrate how to use this Web site for conducting behavioral research and to lower the barrier to entry for researchers who could benefit from this platform. We describe general techniques that apply to a variety of types of research and experiments across disciplines. We begin by discussing some of the advantages of doing experiments on Mechanical Turk, such as easy access to a large, stable, and diverse subject pool, the low cost of doing experiments, and faster iteration between developing theory and executing experiments. While other methods of conducting behavioral research may be comparable to or even better than Mechanical Turk on one or more of the axes outlined above, we will show that when taken as a whole Mechanical Turk can be a useful tool for many researchers. We will discuss how the behavior of workers compares with that of experts and laboratory subjects. Then we will illustrate the mechanics of putting a task on Mechanical Turk, including recruiting subjects, executing the task, and reviewing the work that was submitted. We also provide solutions to common problems that a researcher might face when executing their research on this platform, including techniques for conducting synchronous experiments, methods for ensuring high-quality work, how to keep data private, and how to maintain code security. PMID:21717266

  11. Deep parallel sequencing reveals conserved and novel miRNAs in gill and hepatopancreas of giant freshwater prawn.

    PubMed

    Tan, Tian Tian; Chen, Maoshan; Harikrishna, Jennifer Ann; Khairuddin, Norliana; Mohd Shamsudin, Maizatul Izzah; Zhang, Guojie; Bhassu, Subha

    2013-10-01

    MicroRNAs (miRNAs) are ~20-22 nucleotides, non protein-coding RNA regulatory genes that post-transcriptionally regulate many protein-coding genes, influencing critical biological and metabolic processes. While the number of known microRNA is increasing, there is currently no published data for miRNA from giant freshwater prawns, Macrobrachium rosenbergii (M. rosenbergii), a commercially cultured and economically important food species. In this study, we identified novel miRNAs in the gill and hepatopancreas of M. rosenbergii. Through a deep parallel sequencing analysis and an in silico data analysis approach, 327 miRNA families were identified from small RNA libraries with reference to both the de novo transcriptome of M. rosenbergii obtained from RNA-Seq and to miRBase (Release 18.0, November 2012). Based on the identified mature miRNA and recovered precursor sequences that form appropriate hairpin structures, three conserved miRNA (miR125, miR750, miR993) and 27 novel miRNA candidates encoding messenger-like non-coding RNA were identified. miR-125, miR-750, G-m0002/H-m0009, G-m0005, G-m0008/H-m0016, G-m0011/H-m0027 and G-m0015 were selected for experimental validation with stem-loop quantitative RT-PCR and were found to be coherent with the expression profile of deep sequencing data as evaluated with Pearson's correlation coefficient (r = 0.835178 for miRNA in gill, r = 0.724131 for miRNA in hepatopancreas). Using a combinatorial approach of pathway enrichment analysis and inverse expression relationship of miRNA and mRNA, four co-expressed novel miRNA candidates (G-m0005, G-m0008/H-m0016, G-m0011/H-m0027, and G-m0015) were found to be associated with energy metabolism. In addition, the expression of the three novel miRNA candidates (G-m0005, G-m0008/H-m0016, and G-m0011/H-m0027) were also found to be significantly reduced at 9 and 24 h post infection in M. rosenbergii challenged with infectious hypodermal and hematopoietic necrosis virus, suggesting a functional role of these miRNAs in crustacean immune defense. PMID:23816854

  12. Water balance in the Amazon basin from a land surface model ensemble

    SciTech Connect

    Getirana, Augusto; Dutra, Emanuel; Guimberteau, Matthieu; Kam, Jonghun; Li, Hongyi; Decharme, Bertrand; Zhang, Zhengqiu J.; Ducharne, Agnes; Boone, Aaron; Balsamo, Gianpaolo; Rodell, Matthew; Mounirou Toure, Ally; Xue, Yongkang; Peters-Lidard, Christa D.; Kumar, Sujay V.; Arsenault, Kristi Rae; Drapeau, Guillaume; Leung, Lai-Yung R.; Ronchail, Josyane; Sheffield, Justin

    2014-12-06

    Despite recent advances in modeling and remote sensing of land surfaces, estimates of the global water budget are still fairly uncertain. The objective of this study is to evaluate the water budget of the Amazon basin based on several state-of-the-art land surface model (LSM) outputs. Water budget variables [total water storage (TWS), evapotranspiration (ET), surface runoff (R) and baseflow (B)] are evaluated at the basin scale using both remote sensing and in situ data. Fourteen LSMs were run using meteorological forcings at a 3-hourly time step and 1-degree spatial resolution. Three experiments are performed using precipitation which has been rescaled to match monthly global GPCP and GPCC datasets and the daily HYBAM dataset for the Amazon basin. R and B are used to force the Hydrological Modeling and Analysis Platform (HyMAP) river routing scheme and simulated discharges are compared against observations at 165 gauges. Simulated ET and TWS are compared against FLUXNET and MOD16A2 evapotranspiration, and GRACE TWS estimates in different catchments. At the basin scale, simulated ET ranges from 2.39mm.d-1 to 3.26mm.d-1 and a low spatial correlation between ET and P indicates that evapotranspiration does not depend on water availability over most of the basin. Results also show that other simulated water budget variables vary significantly as a function of both the LSM and precipitation used, but simulated TWS generally agree at the basin scale. The best water budget simulations resulted from experiments using the HYBAM dataset, mostly explained by a denser rainfall gauge network the daily rescaling.

  13. Severity of Scorpion Stings in the Western Brazilian Amazon: A Case-Control Study

    PubMed Central

    Queiroz, Amanda M.; Sampaio, Vanderson S.; Mendonça, Iran; Fé, Nelson F.; Sachett, Jacqueline; Ferreira, Luiz Carlos L.; Feitosa, Esaú; Wen, Fan Hui; Lacerda, Marcus; Monteiro, Wuelton

    2015-01-01

    Background Scorpion stings are a major public health problem in Brazil, with an increasing number of registered cases every year. Affecting mostly vulnerable populations, the phenomenon is not well described and is considered a neglected disease. In Brazil, the use of anti-venom formulations is provided free of charge. The associate scorpion sting case is subject to compulsory reporting. This paper describes the epidemiology and identifies factors associated with severity of scorpions stings in the state of Amazonas, in the Western Brazilian Amazon. Methodology/Principal Findings This study included all cases of scorpion stings in the state of Amazonas reported to the Brazilian Diseases Surveillance System from January 1, 2007 to December 31, 2014. A case-control study was conducted to identify factors associated with scorpions sting severity. A total of 2,120 cases were reported during this period. The mean incidence rate in the Amazonas was 7.6 per 100,000 inhabitants/year. Scorpion stings showed a large spatial distribution in the state and represent a potential occupational health problem for rural populations. There was a positive correlation between the absolute number of cases and the altimetric river levels in the Central (p<0.001; Rs = 0.479 linear) and Southwest (p = 0.032; linear Rs = 0.261) regions of the state. Cases were mostly classified as mild (68.6%), followed by moderate (26.8%), and severe (4.6%). The overall lethality rate was 0.3%. Lethality rate among children ?10 years was 1.3%. Age <10 years [OR = 2.58 (95%CI = 1.47–4.55; p = 0.001)], stings occurring in the rural area [OR = 1.97 (95%CI = 1.18–3.29; p = 0.033) and in the South region of the state [OR = 1.85 (95%CI = 1.17–2.93; p = 0.008)] were independently associated with the risk of developing severity. Conclusions/Significance Scorpion stings show an extensive distribution in the Western Brazilian Amazon threatening especially rural populations, children ?10 in particular. Thus, the mapping of scorpions fauna in different Amazon localities is essential and must be accompanied by the characterization of the main biological activities of the venoms. Urban and farming planning, in parallel with awareness of workers at risk for scorpion stings on the need for personal protective equipment use should be considered as public policies for preventing scorpionism. PMID:26061734

  14. Deforestation and increased flooding of the upper Amazon.

    PubMed

    Gentry, A H; Lopez-Parodi, J

    1980-12-19

    The height of the annual flood crest of the Amazon at Iquitos has increased markedly in the last decade. During this same period, there has been greatly increased deforestation in the upper parts of the Amazon watershed in Peru and Ecuador, but no significant changes in regional patterns of precipitation. The change in Amazonian water balance during the last decade appears to be the result of increased runoff due to deforestation. If so, the long-predicted regional climatic and hydrological changes that would be the expected result of Amazonian deforestation may already be beginning. PMID:17817850

  15. Osteoma in a blue-fronted Amazon parrot (Amazona aestiva).

    PubMed

    Cardoso, João Felipe Rito; Levy, Marcelo Guilherme Bezerra; Liparisi, Flavia; Romão, Mario Antonio Pinto

    2013-09-01

    Osteoma is an uncommon bone formation documented in avian species and other animals. A blue-fronted Amazon parrot (Amazona aestiva) with clinical respiratory symptoms was examined because of a hard mass present on the left nostril. Radiographs suggested a bone tumor, and the mass was surgically excised. Histopathologic examination revealed features of an osteoma. To our knowledge, this is the first description of an osteoma in a blue-fronted Amazon parrot. Osteoma should be considered as a differential diagnosis in birds with respiratory distress and swelling of the nostril. PMID:24344513

  16. Virtual River

    NSDL National Science Digital Library

    This site provides two interactive exercises designed to help the user learn about river processes like discharge, flooding and flood frequency. Both exercises require the user to make observations and measurements, do simple calculations, and answer questions.

  17. River Walk.

    ERIC Educational Resources Information Center

    Schmaus, Marcyes D.

    2001-01-01

    Describes a teaching approach that prompts students to help community, state, and federal agencies make decisions on the best uses of rivers and their surroundings. Includes tracking water quality and designing signs to educate the community. (YDS)

  18. Health, Healthcare Access, and Use of Traditional Versus Modern Medicine in Remote Peruvian Amazon Communities: A Descriptive Study of Knowledge, Attitudes, and Practices

    PubMed Central

    Williamson, Jonathan; Ramirez, Ronald; Wingfield, Tom

    2015-01-01

    There is an urgent need for healthcare research, funding, and infrastructure in the Peruvian Amazon. We performed a descriptive study of health, health knowledge and practice, and healthcare access of 13 remote communities of the Manatí and Amazon Rivers in northeastern Peru. Eighty-five adults attending a medical boat service were interviewed to collect data on socioeconomic position, health, diagnosed illnesses, pain, healthcare access, and traditional versus modern medicine use. In this setting, poverty and gender inequality were prevalent, and healthcare access was limited by long distances to the health post and long waiting times. There was a high burden of reported pain (mainly head and musculoskeletal) and chronic non-communicable diseases, such as hypertension (19%). Nearly all participants felt that they did not completely understand their diagnosed illnesses and wanted to know more. Participants preferred modern over traditional medicine, predominantly because of mistrust or lack of belief in traditional medicine. Our findings provide novel evidence concerning transitional health beliefs, hidden pain, and chronic non-communicable disease prevalence in marginalized communities of the Peruvian Amazon. Healthcare provision was limited by a breach between health education, knowledge, and access. Additional participatory research with similar rural populations is required to inform regional healthcare policy and decision-making. PMID:25688165

  19. Poly-ß-hydroxybutyrate content and dose of the bacterial carrier for Artemia enrichment determine the performance of giant freshwater prawn larvae.

    PubMed

    Thai, Truong Quoc; Wille, Mathieu; Garcia-Gonzalez, Linsey; Sorgeloos, Patrick; Bossier, Peter; De Schryver, Peter

    2014-06-01

    The beneficial effects of poly-?-hydroxybutyrate (PHB) for aquaculture animals have been shown in several studies. The strategy of applying PHB contained in a bacterial carrier has, however, hardly been considered. The effect of administering PHB-accumulated Alcaligenes eutrophus H16 containing 10 or 80 % PHB on dry weight, named A10 and A80, respectively, through the live feed Artemia was investigated on the culture performance of larvae of the giant freshwater prawn (Macrobrachium rosenbergii). Feeding larvae with Artemia nauplii enriched in a medium containing 100 and 1,000 mg L(-1) A80 significantly increased the survival with about 15 % and the development of the larvae with a larval stage index of about 1 as compared to feeding non-enriched Artemia. The survival of the larvae also significantly increased with about 35 % in case of a challenge with Vibrio harveyi. The efficiency of these treatments was equal to a control treatment of Artemia enriched in an 800 mg L(-1) PHB powder suspension, while Artemia enriched in 10 mg L(-1) A80, 100 mg L(-1) A10, and 1,000 mg L(-1) A10 did not bring similar effects. From our results, it can be concluded that PHB supplemented in a bacterial carrier (i.e., amorphous PHB) can increase the larviculture efficiency of giant freshwater prawn similar to supplementation of PHB in powdered form (i.e., crystalline PHB). When the level of PHB in the bacterial carrier is high, similar beneficial effects can be achieved as crystalline PHB, but at a lower live food enrichment concentration expressed on PHB basis. PMID:24615382

  20. Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates in remote Peruvian Amazon?

    PubMed Central

    Aston, Emily J.; Mayor, Pedro; Bowman, Dwight D.; Mohammed, Hussni O.; Liotta, Janice L.; Kwok, Oliver; Dubey, J.P.

    2013-01-01

    Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the modified agglutination test (MAT). These animals were hunted by subsistence hunters along the Yavarí-Mirín River, in the northeastern Peruvian Amazon. Blood samples were collected by hunters on filter papers. For determination of T. gondii antibodies, blood was eluted from filter papers, and a titer of 1:25 was considered indicative of exposure to T. gondii. Antibodies to T. gondii were found in 26 (31.0%) peccaries (Pecari tajacu, Tayassu pecari), six (17.1%) brocket deer (Mazama americana, Mazama gouazoubira), and four (40.0%) lowland tapir (Tapirus terrestris). We also introduced a modification to the MAT protocol that allows the extraction of fluid samples from several types of laboratory-grade filter paper, thus enabling researchers to easily adapt their approaches to the materials presented to them. PMID:24918073

  1. Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates in remote Peruvian Amazon.

    PubMed

    Aston, Emily J; Mayor, Pedro; Bowman, Dwight D; Mohammed, Hussni O; Liotta, Janice L; Kwok, Oliver; Dubey, J P

    2014-04-01

    Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the modified agglutination test (MAT). These animals were hunted by subsistence hunters along the Yavarí-Mirín River, in the northeastern Peruvian Amazon. Blood samples were collected by hunters on filter papers. For determination of T. gondii antibodies, blood was eluted from filter papers, and a titer of 1:25 was considered indicative of exposure to T. gondii. Antibodies to T. gondii were found in 26 (31.0%) peccaries (Pecari tajacu, Tayassu pecari), six (17.1%) brocket deer (Mazama americana, Mazama gouazoubira), and four (40.0%) lowland tapir (Tapirus terrestris). We also introduced a modification to the MAT protocol that allows the extraction of fluid samples from several types of laboratory-grade filter paper, thus enabling researchers to easily adapt their approaches to the materials presented to them. PMID:24918073

  2. Seasonal dynamics and Organic Carbon Flux in the Congo River

    NASA Astrophysics Data System (ADS)

    Seyler, P.; Coynel, A.; Etcheber, H.; Meybeck, M.

    2006-12-01

    The Congo (Zaire) River, the second world river in terms of discharges and drainage area (Q=40600 m3/s; A=3.5 106 km2) after the Amazon River, is -up to now- in near-pristine state. For up to two years , the mainstream near river mouth (Kinshasa/Brazzaville station) and some major and minor tributaries (Oubangui, Mpoko and Ngoko-Sangha) were surveyed every month, for total suspended sediment (TSS), particulate organic carbon (POC) and dissolved organic carbon (DOC). In this very flat basin, TSS levels were very low and organic carbon was essentially exported as DOC: 74% of TOC for the tributaries flowing in savannah regions to 86% for those flowing in the rainforest). The seasonal patterns of TSS, POC and DOC showed clockwise hysteresis with river discharges, with maximum levels two to four months before peak flows. At the Kinshasa/Brazzaville station, the DOC distribution is largely influenced by the input of the tributaries draining the marshy forest area (Central depression). In term of fluxes, a marked difference is pointed out between specific fluxes, threefold higher in the forested basin than in savannahs basins. Computation of inputs to Atlantic Ocean showed that the Congo was responsible for 14.4 106 t/yr of TOC of which 12.4 106 t/yr is DOC and 2 106 t/yr is POC. The three biggest tropical rivers (Amazon, Congo and Orinoco) with only 10 percent of the exoreic world area drained to ocean world contribute to 4 percent of its TSS inputs but 29-33 percent of its organic carbon inputs.

  3. Mimivirus Circulation among Wild and Domestic Mammals, Amazon Region, Brazil

    PubMed Central

    Dornas, Fábio P.; Rodrigues, Felipe P.; Boratto, Paulo V.M.; Silva, Lorena C.F.; Ferreira, Paulo C.P.; Bonjardim, Cláudio A.; Trindade, Giliane S.; Kroon, Erna G.; La Scola, Bernard

    2014-01-01

    To investigate circulation of mimiviruses in the Amazon Region of Brazil, we surveyed 513 serum samples from domestic and wild mammals. Neutralizing antibodies were detected in 15 sample pools, and mimivirus DNA was detected in 9 pools of serum from capuchin monkeys and in 16 pools of serum from cattle. PMID:24564967

  4. Modification of Atmospheric Circulations and Transports due to Amazon Deforestation

    NASA Astrophysics Data System (ADS)

    Badger, A.; Dirmeyer, P.

    2013-12-01

    Land-use change (LUC) has generally been considered a local environmental issue, but it is now becoming a force of global importance. LUC occurs on local scales, with real world social and economic benefits, that can potentially cause ecological degradation. Large-scale LUC, such as deforestation in the Amazon, can have a significant local affect on the climate and has the potential to impact the regional and global climate systems. Previous climate modeling studies have shown non-local responses due to Amazon deforestation, however, a common flaw in these studies is the use of prescribed ocean conditions, which can dampen the global response. Using fully coupled modeling simulations with the Community Earth System Model version 1.2.0, the Amazon rainforest has been replaced with a distribution of representative tropical crops. The degree of modification to the general circulation due to heating anomalies in the tropics as a response to the removal of the Amazon rainforest is quantified. Most notably, modifications to the Hadley and Walker circulations, the two fundamental circulations mediating the climate at low latitudes, occur. Coupling these circulation changes with sensible heat and latent heat fluxes, atmospheric transports of heat and moisture are affected both regionally and globally.

  5. Risk Assessment of Mercury in Alta Floresta. Amazon Basin - Brazil

    Microsoft Academic Search

    S. Hacon; E. R Rochedo; R. Campos; G. Rosales; L. D. Lacerda

    1997-01-01

    In the last 15 years gold mining activity has been the main source of the mercury (Hg) emissions into the atmosphere in the Amazon Basin. The first phase of gold production takes place in remote areas. In general the second one happens in the local urban area, where the gold is commercialized and sent to the great economic centers. In

  6. The local and global effects of Amazon deforestation

    Microsoft Academic Search

    David Werth; Roni Avissar

    2002-01-01

    To quantify the effects of land cover changes in the Amazon on local and global climate, numerical simulation experiments using the Goddard Institute for Space Studies Model II global climate model are conducted. An ensemble approach is adopted, in which a group of six control simulations is compared with a group of six deforested simulations. The deforestation effect in the

  7. Deforestation and land use in the Brazilian Amazon

    Microsoft Academic Search

    Emilio F. Moran

    1993-01-01

    Deforestation in the Brazilian Amazon was less than 1% before 1975. Between 1975 and 1987 the rate increased exponentially. By 1985, world opinion and attention to the destruction of the richest biome on earth led to elimination of some of the major incentives that had fueled deforestation. Favorable credit policies for cattle ranchers, rather than population growth, explains the process

  8. Inundation, Wetland Vegetation and Biogeochemical Processes in the Amazon Basin

    Microsoft Academic Search

    J. M. Melack; L. L. Hess; S. K. Hamilton; J. E. Richey; E. M. Novo

    2001-01-01

    Remote sensing of the Amazon basin with passive and active microwave techniques were applied to determine the temporally varying extent of inundation and associated vegetation, and used in conjunction with field measurements to calculate regional rates of carbon dioxide emission from wetlands to the atmosphere. Monthly inundation areas were derived from analysis of the 37-GHz polarization difference observed by the

  9. Amazon plant diversity and climate through the Cenozoic

    Microsoft Academic Search

    P. A. Colinvauxa

    The modern Amazon lowlands date from the mid-Cenozoic, when the Andean orogeny defined an eastward, or northward draining basin of immense size. As the Andean orogeny continued throughout the Neogene and Quaternary periods, this system approached a steady state, with Andean flanks eroding to fill subsiding basins along the Andean foreland, followed by secondary erosion of sediments and transport in

  10. Amazon plant diversity and climate through the Cenozoic

    Microsoft Academic Search

    P. A. Colinvaux; P. E. De Oliveira

    2001-01-01

    The modern Amazon lowlands date from the mid-Cenozoic, when the Andean orogeny defined an eastward, or northward draining basin of immense size. As the Andean orogeny continued throughout the Neogene and Quaternary periods, this system approached a steady state, with Andean flanks eroding to fill subsiding basins along the Andean foreland, followed by secondary erosion of sediments and transport in

  11. The Amazon Land War in the South of Pará

    Microsoft Academic Search

    Cynthia S. Simmons; Robert T. Walker; Eugenio Y. Arima; Stephen P. Aldrich; Marcellus M. Caldas

    2007-01-01

    The South of Pará, located in the heart of the Brazilian Amazon, has become notorious for violent land struggle. Although land conflict has a long history in Brazil, and today impacts many parts of the country, violence is most severe and persistent here. The purpose of this article is to examine why. Specifically, we consider how a particular Amazonian place,

  12. Is oil palm the next emerging threat to the Amazon?

    Microsoft Academic Search

    Rhett A. Butler; William F. Laurance

    2009-01-01

    The Amazon Basin appears poised to experience rapid expansion of oil palm agriculture. Nearly half of Amazonia is suitable for oil palm cultivation, and Malaysian corporations are now moving into the region to establish new plantations while the Brazilian government is considering a law that would count oil palm as \\

  13. Lipid Panel Reference Intervals for Amazon Parrots (Amazona species).

    PubMed

    Ravich, Michelle; Cray, Carolyn; Hess, Laurie; Arheart, Kristopher L

    2014-09-01

    The lipoprotein panel is a useful diagnostic tool that allows clinicians to evaluate blood lipoprotein fractions. It is a standard diagnostic test in human medicine but is poorly understood in avian medicine. Amazon parrots (Amazona species) are popular pets that frequently lead a sedentary lifestyle and are customarily fed high-fat diets. Similar to people with comparable diets and lifestyles, Amazon parrots are prone to obesity and atherosclerosis. In human medicine, these conditions are typically correlated with abnormalities in the lipoprotein panel. To establish reference intervals for the lipoprotein panel in Amazon parrots, plasma samples from 31 captive Amazon parrots were analyzed for concentrations of cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL). The data were also grouped according to sex, diet, body condition score, and age. Aside from HDL levels, which were significantly different between male and female parrots, no intergroup differences were found for any of the lipoprotein fractions. PMID:25843320

  14. Phonation in the Orange-winged Amazon parrot, Amazona amazonica

    Microsoft Academic Search

    Fernando Nottebohm

    1976-01-01

    Summary The syrinx of the Orange-winged Amazon parrot includes two external tympaniform membranes thought to be involved in sound production. The position of these membranes at the confluence of the bronchial and tracheal lumina requires that during phonation they be driven by a single column of air and by its attending turbulence patterns. Because of this anatomical arrangement, the phonatory

  15. Links between Climate, Malaria, and Wetlands in the Amazon Basin

    PubMed Central

    Gangnon, Ronald; Elguero, Eric; Durieux, Laurent; Guégan, Jean-François; Foley, Jonathan A.; Patz, Jonathan A.

    2009-01-01

    Climate changes are altering patterns of temperature and precipitation, potentially affecting regions of malaria transmission. We show that areas of the Amazon Basin with few wetlands show a variable relationship between precipitation and malaria, while areas with extensive wetlands show a negative relationship with malaria incidence. PMID:19331766

  16. Amazon Fan biomarker evidence against the Pleistocene rainforest refuge hypothesis?

    E-print Network

    Jones, Peter JS

    Amazon Fan biomarker evidence against the Pleistocene rainforest refuge hypothesis? MARK A. MASLIN; biomarker; Pleistocene; rainforest. Introduction Tropical rainforests display a level of biodiversity rainforest refuge hypothesis' (e.g. Haffer, 1969; Haffer and Prance, 2001). It has been suggested that

  17. Contrasting convective regimes over the Amazon: Implications for cloud electrification

    Microsoft Academic Search

    E. Williams; D. Rosenfeld; N. Madden; J. Gerlach; N. Gears; L. Atkinson; N. Dunnemann; G. Frostrom; M. Antonio; B. Biazon; R. Camargo; H. Franca; A. Gomes; M. Lima; R. Machado; S. Manhaes; L. Nachtigall; H. Piva; W. Quintiliano; L. Machado; P. Artaxo; G. Roberts; N. Renno; R. Blakeslee; J. Bailey; D. Boccippio; A. Betts; D. Wolff; B. Roy; J. Halverson; T. Rickenbach; J. Fuentes; E. Avelino

    2002-01-01

    Four distinct meteorological regimes in the Amazon basin have been examined to distinguish the contributions from boundary layer aerosol and convective available potential energy (CAPE) to continental cloud structure and electrification. The lack of distinction in the electrical parameters (peak flash rate, lightning yield per unit rainfall) between aerosol-rich October and aerosol-poor November in the premonsoon regime casts doubt on

  18. Neogene origins and implied warmth tolerance of Amazon tree species.

    PubMed

    Dick, Christopher W; Lewis, Simon L; Maslin, Mark; Bermingham, Eldredge

    2012-01-01

    Tropical rain forest has been a persistent feature in South America for at least 55 million years. The future of the contemporary Amazon forest is uncertain, however, as the region is entering conditions with no past analogue, combining rapidly increasing air temperatures, high atmospheric carbon dioxide concentrations, possible extreme droughts, and extensive removal and modification by humans. Given the long-term Cenozoic cooling trend, it is unknown whether Amazon forests can tolerate air temperature increases, with suggestions that lowland forests lack warm-adapted taxa, leading to inevitable species losses. In response to this uncertainty, we posit a simple hypothesis: the older the age of a species prior to the Pleistocene, the warmer the climate it has previously survived, with Pliocene (2.6-5 Ma) and late-Miocene (8-10 Ma) air temperature across Amazonia being similar to 2100 temperature projections under low and high carbon emission scenarios, respectively. Using comparative phylogeographic analyses, we show that 9 of 12 widespread Amazon tree species have Pliocene or earlier lineages (>2.6 Ma), with seven dating from the Miocene (>5.6 Ma) and three >8 Ma. The remarkably old age of these species suggest that Amazon forests passed through warmth similar to 2100 levels and that, in the absence of other major environmental changes, near-term high temperature-induced mass species extinction is unlikely. PMID:23404439

  19. Neogene origins and implied warmth tolerance of Amazon tree species

    E-print Network

    Jones, Peter JS

    Street, UCL, London, WC1E 6BT, U.K. Keywords Amazon forests, comparative phylogeography, ecological niche that lowland forests lack warm-adapted taxa, leading to inevitable species losses. In response L. Lewis3,4 , Mark Maslin4 & Eldredge Bermingham2 1 Department of Ecology and Evolutionary Biology

  20. Spectral dependence of aerosol light absorption over the Amazon Basin

    Microsoft Academic Search

    L. V. Rizzo; A. L. Correia; P. Artaxo; A. S. Procópio; M. O. Andreae

    2011-01-01

    In this study, we examine the spectral dependence of aerosol absorption at different sites and seasons in the Amazon Basin. The analysis is based on measurements performed during three intensive field experiments at a pasture site (Fazenda Nossa Senhora, Rondônia) and at a primary forest site (Cuieiras Reserve, Amazonas), from 1999 to 2004. Aerosol absorption spectra were measured using two

  1. Extreme Drought Events Revealed in Amazon Tree Ring Records

    NASA Astrophysics Data System (ADS)

    Jenkins, H. S.; Baker, P. A.; Guilderson, T. P.

    2010-12-01

    The Amazon basin is a center of deep atmospheric convection and thus acts as a major engine for global hydrologic circulation. Yet despite its significance, a full understanding of Amazon rainfall variability remains elusive due to a poor historical record of climate. Temperate tree rings have been used extensively to reconstruct climate over the last thousand years, however less attention has been given to the application of dendrochronology in tropical regions, in large part due to a lower frequency of tree species known to produce annual rings. Here we present a tree ring record of drought extremes from the Madre de Dios region of southeastern Peru over the last 190 years. We confirm that tree ring growth in species Cedrela odorata is annual and show it to be well correlated with wet season precipitation. This correlation is used to identify extreme dry (and wet) events that have occurred in the past. We focus on drought events identified in the record as drought frequency is expected to increase over the Amazon in a warming climate. The Cedrela chronology records historic Amazon droughts of the 20th century previously identified in the literature and extends the record of drought for this region to the year 1816. Our analysis shows that there has been an increase in the frequency of extreme drought (mean recurrence interval = 5-6 years) since the turn of the 20th century and both Atlantic and Pacific sea surface temperature (SST) forcing mechanisms are implicated.

  2. Large seasonal swings in leaf area of Amazon rainforests

    E-print Network

    Myneni, Ranga B.

    Large seasonal swings in leaf area of Amazon rainforests Ranga B. Mynenia , Wenze Yanga Drive, Pasadena, CA 91109; hCalifornia State University at Monterey Bay and Ecosystem Science but not on the accompanying changes in leaf area that regulate vegetation­atmosphere ex- changes of energy, momentum, and mass

  3. Population genetic structure and vocal dialects in an amazon parrot

    Microsoft Academic Search

    Timothy F. Wright; Gerald S. Wilkinson

    2001-01-01

    The relationship between cultural and genetic evolution was examined in the yellow-naped amazon Amazona auropalliata. This species has previously been shown to have regional dialects de¢ned by large shifts in the acoustic structure of its learned contact call. Mitochondrial DNA sequence variation from a 680 base pair segment of the ¢rst domain of the control region was assayed in 41

  4. Potential Effects of Amazon Deforestation on Tropical Climate

    NSDL National Science Digital Library

    This report describes the results of a study in which climate modeling was used to examine the effects of deforestation in the Amazon basin. The study concluded that changes in land surface properties (loss of forest cover) cause changes in the mean surface wind stress in the tropical Pacific, which in turn results in increased variability of El Nino/Southern Oscillation (ENSO) events.

  5. Neogene origins and implied warmth tolerance of Amazon tree species

    PubMed Central

    Dick, Christopher W; Lewis, Simon L; Maslin, Mark; Bermingham, Eldredge

    2013-01-01

    Tropical rain forest has been a persistent feature in South America for at least 55 million years. The future of the contemporary Amazon forest is uncertain, however, as the region is entering conditions with no past analogue, combining rapidly increasing air temperatures, high atmospheric carbon dioxide concentrations, possible extreme droughts, and extensive removal and modification by humans. Given the long-term Cenozoic cooling trend, it is unknown whether Amazon forests can tolerate air temperature increases, with suggestions that lowland forests lack warm-adapted taxa, leading to inevitable species losses. In response to this uncertainty, we posit a simple hypothesis: the older the age of a species prior to the Pleistocene, the warmer the climate it has previously survived, with Pliocene (2.6–5 Ma) and late-Miocene (8–10 Ma) air temperature across Amazonia being similar to 2100 temperature projections under low and high carbon emission scenarios, respectively. Using comparative phylogeographic analyses, we show that 9 of 12 widespread Amazon tree species have Pliocene or earlier lineages (>2.6 Ma), with seven dating from the Miocene (>5.6 Ma) and three >8 Ma. The remarkably old age of these species suggest that Amazon forests passed through warmth similar to 2100 levels and that, in the absence of other major environmental changes, near-term high temperature-induced mass species extinction is unlikely. PMID:23404439

  6. Long-term decline of the Amazon carbon sink

    NASA Astrophysics Data System (ADS)

    Brienen, R. J. W.; Phillips, O. L.; Feldpausch, T. R.; Gloor, E.; Baker, T. R.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Lewis, S. L.; Vásquez Martinez, R.; Alexiades, M.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragão, L. E. O. C.; Araujo-Murakami, A.; Arets, E. J. M. M.; Arroyo, L.; Aymard C., G. A.; Bánki, O. S.; Baraloto, C.; Barroso, J.; Bonal, D.; Boot, R. G. A.; Camargo, J. L. C.; Castilho, C. V.; Chama, V.; Chao, K. J.; Chave, J.; Comiskey, J. A.; Cornejo Valverde, F.; da Costa, L.; de Oliveira, E. A.; di Fiore, A.; Erwin, T. L.; Fauset, S.; Forsthofer, M.; Galbraith, D. R.; Grahame, E. S.; Groot, N.; Hérault, B.; Higuchi, N.; Honorio Coronado, E. N.; Keeling, H.; Killeen, T. J.; Laurance, W. F.; Laurance, S.; Licona, J.; Magnussen, W. E.; Marimon, B. S.; Marimon-Junior, B. H.; Mendoza, C.; Neill, D. A.; Nogueira, E. M.; Núñez, P.; Pallqui Camacho, N. C.; Parada, A.; Pardo-Molina, G.; Peacock, J.; Peña-Claros, M.; Pickavance, G. C.; Pitman, N. C. A.; Poorter, L.; Prieto, A.; Quesada, C. A.; Ramírez, F.; Ramírez-Angulo, H.; Restrepo, Z.; Roopsind, A.; Rudas, A.; Salomão, R. P.; Schwarz, M.; Silva, N.; Silva-Espejo, J. E.; Silveira, M.; Stropp, J.; Talbot, J.; Ter Steege, H.; Teran-Aguilar, J.; Terborgh, J.; Thomas-Caesar, R.; Toledo, M.; Torello-Raventos, M.; Umetsu, R. K.; van der Heijden, G. M. F.; van der Hout, P.; Guimarães Vieira, I. C.; Vieira, S. A.; Vilanova, E.; Vos, V. A.; Zagt, R. J.

    2015-03-01

    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

  7. Deforestation in the Brazilian Amazon: A Classroom Project.

    ERIC Educational Resources Information Center

    Nijman, Jan; Hill, A. David

    1991-01-01

    Presents a classroom project dealing with tropical deforestation in the Brazilian Amazon. Addresses environmental consequences and economic, social, and political causes. Involves both lectures and individual research and reports by student groups on deforestation causes. Includes a note-playing activity in which students make recommendations for…

  8. Spatial Pattern of Standing Timber Value across the Brazilian Amazon

    PubMed Central

    Ahmed, Sadia E.; Ewers, Robert M.

    2012-01-01

    The Amazon is a globally important system, providing a host of ecosystem services from climate regulation to food sources. It is also home to a quarter of all global diversity. Large swathes of forest are removed each year, and many models have attempted to predict the spatial patterns of this forest loss. The spatial patterns of deforestation are determined largely by the patterns of roads that open access to frontier areas and expansion of the road network in the Amazon is largely determined by profit seeking logging activities. Here we present predictions for the spatial distribution of standing value of timber across the Amazon. We show that the patterns of timber value reflect large-scale ecological gradients, determining the spatial distribution of functional traits of trees which are, in turn, correlated with timber values. We expect that understanding the spatial patterns of timber value across the Amazon will aid predictions of logging movements and thus predictions of potential future road developments. These predictions in turn will be of great use in estimating the spatial patterns of deforestation in this globally important biome. PMID:22590520

  9. Land management impacts on runoff sources in small Amazon watersheds

    Microsoft Academic Search

    Joaquín Chaves; Christopher Neill; Sonja Germer; Sérgio Gouveia Neto; Alex Krusche; Helmut Elsenbeer

    2008-01-01

    Forest clearing and conversion to cattle pasture in the lowland Amazon region has been linked to soil compaction and increased soil water storage, which combine to diminish soil infiltration, enhance quick lateral flows and increase the stream flow response to precipitation. Quantifying the importance of quick surficial flow in response to this land use change requires identification of water sources

  10. Mayaro Virus Infection, Amazon Basin Region, Peru, 2010–2013

    PubMed Central

    Siles, Crystyan; Guevara, Carolina; Vilcarromero, Stalin; Jhonston, Erik J.; Ramal, Cesar; Aguilar, Patricia V.; Ampuero, Julia S.

    2013-01-01

    During 2010–2013, we recruited 16 persons with confirmed Mayaro virus infection in the Peruvian Amazon to prospectively follow clinical symptoms and serologic response over a 12-month period. Mayaro virus infection caused long-term arthralgia in more than half, similar to reports of other arthritogenic alphaviruses. PMID:24210165

  11. Contentious Land Change in the Amazon's Arc of Deforestation

    Microsoft Academic Search

    Stephen Aldrich; Robert Walker; Cynthia Simmons; Marcellus Caldas; Stephen Perz

    2011-01-01

    Land change in the Amazon is driven by numerous factors including fiscal incentives, infrastructure, transportation costs, migration, and household decision making. Largely missing from the story to date, however, is the role of contentious social processes, including contention over land resources. By employing a case study of land conflict over a largeholding in southeastern Pará, Brazil, and a regional-scale statistical

  12. Conservation and environmental concerns in the Venezuelan Amazon

    Microsoft Academic Search

    Otto Huber

    2001-01-01

    Starting in 1978, a vigorous conservation policy was established in Estado Amazonas, then the still remote and isolated southernmost part of Venezuela, covering approximately 175 750 km2. At present, four national parks, 17 natural monuments and one biosphere reserve exist in the Venezuelan Amazon, including approx. 92 000 km2; furthermore, since January 1978 all commercial logging activities, and since June

  13. Contentious Land Change in the Amazon's Arc of Deforestation

    Microsoft Academic Search

    Stephen Aldrich; Robert Walker; Cynthia Simmons; Marcellus Caldas; Stephen Perz

    2012-01-01

    Land change in the Amazon is driven by numerous factors including fiscal incentives, infrastructure, transportation costs, migration, and household decision making. Largely missing from the story to date, however, is the role of contentious social processes, including contention over land resources. By employing a case study of land conflict over a largeholding in southeastern Pará, Brazil, and a regional-scale statistical

  14. Panorama from the top of Amazon Observation Tower

    USGS Multimedia Gallery

    Panorama (360 degree) view from the top of a 148-foot (45-meter) observation tower at the Amazon forest study site near Santarém, Brazil.  The instrument on the tower, the USGS High Dynamic Range All-Sky Imaging System (HDR-ASIS), monitors atmospheric conditions and the solar radiation a...

  15. Comparison of CCN activity measured in pristine and polluted sites during the Intensive Operation Periods (IOP) of the GoAmazon 2014 campaign

    NASA Astrophysics Data System (ADS)

    Barbosa, H. M.; Krüger, M. L.; Thalman, R. M.; Wang, J.; Pauliquevis, T.; Ferreira De Brito, J.; Almeida, G. P.; Poeschl, U.; Andreae, M. O.; Martin, S. T.; Artaxo, P.; Souza, R. A. F. D.; Cirino, G. G.; Andrade, M. D. F.

    2014-12-01

    The effects of aerosol particles on cloud microphysical properties, cloud cover, precipitation, and regional climate are significant. The Amazon region is particularly susceptible to changes in number-diameter distributions of the atmospheric particle population because of the low background concentrations and high water vapor levels, indicating a regime of cloud properties that is highly sensitive to aerosol microphysics. A particle-limited regime means that for modest to vigorous updrafts the cloud droplet number concentration (CDNC) is dominated by CCN number instead of updraft velocity. This natural regime, different from most other continental areas worldwide, is expected to be disrupted by the interaction of Manaus urban plume with the natural aerosol population. Studying the effects of this interaction on the cloud and aerosol life cycle is the main objective of the Green Ocean Amazon (GoAmazon) campaign taking place around Manaus-Brazil from January 2014 to December 2015. In this paper we compare the particle hygroscopicity calculated from measurements of size-resolved cloud condensation nuclei performed at three ground sites during the first and second intensive operational periods. Site T3 is about 70km downwind from Manaus experiencing urban polluted and background conditions; site T2 is just across the Negro river from Manaus and operated only for the second IOP; and T0, at the Amazon Tall Tower Observatory (ATTO), is a pristine site about 200km upwind from Manaus. Our results indicate a lower hygroscopicity under polluted conditions, with mean value around 0.14 to 0.16, than under clean conditions, with a mean value around 0.2 to 0.3. At the clean site, it was possible to identify peaks of large sea salt particles with organic coating, while small particles seems to be pure organic. The activation fraction and hygroscopicity will be compared and discussed as a function of particle size.

  16. Subcellular\\/tissue distribution and responses to oil exposure of the cytochrome P450-dependent monooxygenase system and glutathione S-transferase in freshwater prawns ( Macrobrachium malcolmsonii, M. lamarrei lamarrei )

    Microsoft Academic Search

    S. Arun; A. Rajendran; P. Subramanian

    2006-01-01

    Subcellular fractions (mitochondrial, cytosolic and microsomal) prepared from the tissues (hepatopancreas, muscle and gill) of freshwater prawns Macrobrachium malcolmsonii and Macrobrachium lamarrei lamarrei were scrutinized to investigate the presence of mixed function oxygenase (MFO) and conjugating enzymes (glutathione-S-transferase, GST). Cytochrome P450 (CYP) and other components (cytochrome b5; NADPH-cytochrome c (CYP) reductase and NADH-cytochrome c-reductase activities) of the MFO system were

  17. Using performance indicators to evaluate an environmental education program in artisanal gold mining communities in the Brazilian Amazon.

    PubMed

    Sousa, Rodolfo N; Veiga, Marcello M

    2009-02-01

    The Tapajos River Basin in the Brazilian Amazon is the location of one of the largest concentrations of artisanal and small-scale miners in the world. Today, 40,000 miners produce 8 t of gold annum(-1) and at least double this amount of mercury is released into the environment. This region was selected under the Global Mercury Project, a United Nations program that aims to reduce the environmental and health impacts caused by mercury through the application of cleaner technologies and increased awareness. A group of educators provided support to miners, training 4200 people in 141 mining locations. The effectiveness of this training was evaluated based on 20 performance indicators. After 120 days of training, an absolute improvement of approximately 29% had been achieved. As a result of this training, it is estimated that annual mercury emissions in Tapajos have been reduced by 1762 kg or around 10% of the total mercury released in the region. PMID:19260346

  18. Anabranching Channel Patterns: the Kingdom of Large Alluvial Rivers

    NASA Astrophysics Data System (ADS)

    Latrubesse, Edgardo

    2015-04-01

    For a long time anabranching patterns were primarily restricted to "exotic and remote" zones in arid systems such as Australia. For that reason, they were not accepted as a major topic of discussion in our discipline, which was based on concepts principally derived from case studies in braided and meandering rivers of the Northern Hemisphere. However, anabranching alluvial patterns are widespread in a variety of environments and scales, from arid small rivers to alluvial reaches of giant rivers such as the Amazon, Congo, and Negro. The largest rivers of the world in water discharge are anabranching, and the majority of the forty-five largest rivers (water discharges >5000m3s-1) are dominantly anabranching systems. Only a small number of rivers with meandering patterns, or sinuous with branches (meandering-tendency to anabranch) are part of the largest rivers group. The present large anabranching rivers flowing on lowlands and well developed floodplains have in common a characteristic very slow slopes, specific stream power of < 25 Wm-2 and sandy bed load with sand sizes dominantly ranging from 0.1 < D50 <0.5 mm. The diversity of planforms and island morphologies in large anabranching rivers result from autogenic adjustments to millennial scales in broad valleys and to century-decadal scale channel-floodplain processes. The variety of anabranching styles are not specifically related to a single explanatory "physically based theory" but to a variety of morphological processes, complex-channel floodplain interactions and the geologic characteristics of the valleys. Once considered a kind of oddity, anabranching rivers must be considered major and fundamental representatives of the fluvial world.

  19. Rules of the River.

    E-print Network

    Anonymous,

    1980-01-01

    DO /~ TA245.7 8-1304 873 ~Ies of the River The Te>River Recreation... Association of Texas, P.O. Box 12734, Austin, Texas 78711, 1979. Sketches by Barbara Moore. -, ? ? ? ? Rules of the River These "Rules of the River" are for you, the river recreationist . River recreation is increasing in Texas. Recent surveys show...

  20. Trophic Structure and Mercury Biomagnification in Tropical Fish Assemblages, Iténez River, Bolivia

    PubMed Central

    Pouilly, Marc; Rejas, Danny; Pérez, Tamara; Duprey, Jean-Louis; Molina, Carlos I.; Hubas, Cédric; Guimarães, Jean-Remy D.

    2013-01-01

    We examined mercury concentrations in three fish assemblages to estimate biomagnification rates in the Iténez main river, affected by anthropogenic activities, and two unperturbed rivers from the Iténez basin, Bolivian Amazon. Rivers presented low to moderate water mercury concentrations (from 1.25 ng L?1 to 2.96 ng L?1) and natural differences in terms of sediment load. Mercury biomagnification rates were confronted to trophic structure depicted by carbon and nitrogen stable isotopes composition (?15N; ?13C) of primary trophic sources, invertebrates and fishes. Results showed a slight fish contamination in the Iténez River compared to the unperturbed rivers, with higher mercury concentrations in piscivore species (0.15 µg g?1 vs. 0.11 µg g?1 in the unperturbed rivers) and a higher biomagnification rate. Trophic structure analysis showed that the higher biomagnification rate in the Iténez River could not be attributed to a longer food chain. Nevertheless, it revealed for the Iténez River a higher contribution of periphyton to the diet of the primary consumers fish species; and more negative ?13C values for primary trophic sources, invertebrates and fishes that could indicate a higher contribution of methanotrophic bacteria. These two factors may enhance methylation and methyl mercury transfer in the food web and thus, alternatively or complementarily to the impact of the anthropogenic activities, may explain mercury differences observed in fishes from the Iténez River in comparison to the two other rivers. PMID:23741452

  1. Philometra mirabilis sp. n. (Nematoda: Philometridae), a new gonad-infecting parasite from the freshwater fish Cichla mirianae (Cichlidae) in Brazilian Amazon.

    PubMed

    Moravec, František; Diggles, Ben

    2015-05-01

    A new nematode species, Philometra mirabilis sp. n. (Philometridae), is described based on a subgravid female specimen recovered from the ovary of the freshwater perciform fish Cichla mirianae Kullander and Ferreira (Cichlidae) in the Juruena River (Amazon River basin), State of Mato Grosso, Brazil. The new species is morphologically very different from congeners parasitizing fishes in South America, being mainly characterized by the markedly elongate, narrow body 171 mm long (maximum width/body length 1:598), the presence of three small cone-shaped oesophageal teeth protruding out of the mouth and an onion-shaped oesophageal inflation distinctly separated from the posterior part of the oesophagus, the relative length of the oesophagus, and the rounded posterior end of the body without any caudal projections. It is the third known valid species of Philometra Costa, 1845 parasitizing a freshwater fish in South America and the second species of this genus reported from fishes of the family Cichlidae. PMID:25855348

  2. A Metalloproteomics Study on the Association of Mercury With Breast Milk in Samples From Lactating Women in the Amazon Region of Brazil.

    PubMed

    Dos Santos, Felipe André; Cavecci, Bruna; Vieira, José Cavalcante Souza; Franzini, Vanessa Pezza; Santos, Ademir; de Lima Leite, Aline; Buzalaf, Marília Afonso Rabelo; Zara, Luiz Fabrício; de Magalhães Padilha, Pedro

    2015-08-01

    This study aimed to identify metalloproteins that lose their metal ions in the presence of mercury (Hg) and bind to Hg in breast milk samples collected from the riverine population of the Madeira River, a tributary of the Amazon River. Initially, total Hg was determined from the hair of lactating women to identify individuals who were contaminated followed by a proteomic analysis of breast milk samples through two-dimensional polyacrylamide gel electrophoresis after acetone precipitation. The presence of Hg in the obtained protein spots was determined by cold vapor atomic absorption spectrometry and cold vapor atomic fluorescence spectrometry. These determinations indicated the presence of Hg in one protein spot, which was then characterized through electrospray ionization tandem mass spectrometry. Based on searches in the UniProt database, this protein spot was identified as lysozyme C. PMID:25981408

  3. 33 CFR 162.90 - White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...Waterways. White River between Mississippi River and Arkansas Post Canal,...

  4. 33 CFR 162.90 - White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...Waterways. White River between Mississippi River and Arkansas Post Canal,...

  5. 33 CFR 162.90 - White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...Waterways. White River between Mississippi River and Arkansas Post Canal,...

  6. 33 CFR 162.90 - White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...and Verdigris River between Mississippi River, Ark., and Catoosa, Okla...Waterways. White River between Mississippi River and Arkansas Post Canal,...

  7. Souris River

    USGS Multimedia Gallery

     Souris River near Sherwood, North Dakota. A USGS streamflow gage is located at this site, left of the house by some trees. Streamflow was approximately 26,700 cubic feet per second, stage approximately 27.79 feet, on June 23, 2011. Photo taken by USGS personnel on a Civil ...

  8. Knowledge River

    ERIC Educational Resources Information Center

    Berry, John N., III

    2004-01-01

    One of the most promising of all diversity initiatives in library and information studies (LIS) is Knowledge River (KR) at the School of Information Resources and Library Science (SIRLS) at the University of Arizona, Tucson. Created and directed by Patricia A. Tarin, the program has already recruited some 42 students into the profession, 20 of…

  9. Strategies and equipment for sampling suspended sediment and associated toxic chemicals in large rivers - with emphasis on the Mississippi River

    USGS Publications Warehouse

    Meade, R.H.; Stevens, H.H., Jr.

    1990-01-01

    A Lagrangian strategy for sampling large rivers, which was developed and tested in the Orinoco and Amazon Rivers of South America during the early 1980s, is now being applied to the study of toxic chemicals in the Mississippi River. A series of 15-20 cross-sections of the Mississippi mainstem and its principal tributaries is sampled by boat in downstream sequence, beginning upriver of St. Louis and concluding downriver of New Orleans 3 weeks later. The timing of the downstream sampling sequence approximates the travel time of the river water. Samples at each cross-section are discharge-weighted to provide concentrations of dissolved and suspended constituents that are converted to fluxes. Water-sediment mixtures are collected from 10-40 equally spaced points across the river width by sequential depth integration at a uniform vertical transit rate. Essential equipment includes (i) a hydraulic winch, for sensitive control of vertical transit rates, and (ii) a collapsible-bag sampler, which allows integrated samples to be collected at all depths in the river. A section is usually sampled in 4-8 h, for a total sample recovery of 100-120 l. Sampled concentrations of suspended silt and clay are reproducible within 3%.

  10. Acute toxicity and histopathology in ornamental fish amazon bluespotted corydora (Corydoras melanistius) exposed to formalin.

    PubMed

    Santos, Rudã F B; Dias, Henrique M; Fujimoto, Rodrigo Y

    2012-12-01

    The objective of this work was to evaluate the acute toxicity of formalin and histopathological effects on the Amazon ornamental fish, bluespotted coridora (Corydoras melanistius). A randomized design was used, with ten concentrations of formalin (40%) (0, 3, 6, 12, 25, 50, 100, 150, 200 and 250 mg.L(-1)) with four replicates and five fish per container (3L) in static system for 96 hours. The moribund fish were killed and fixed in 10% formalin to proceed the histopathological analysis of gill, liver and kidney. At the end of this experiment the following mortality rates (%) were obtained in increasing order of exposure: 0, 0, 0, 0, 0, 65, 85, 100, 100 and 100%. The lethal concentration 50% (LC(50-96h (I))) estimated was 50.76 mg.L(-1) with regression of y = 0.51x, and r(2) = 0.80. Further, in higher concentrations morphological changes as gill hyperplasia, with filling of interlamellar spaces, disorganization of liver arrangement, and necrosis in kidney were observed. In this study, the formalin can be considered slightly toxic to bluespotted corydora, and cause morphological changes when exposed to high concentrations. The use of formalin to treat of ornamental fish in the inner river of capture with wrong concentration can provoke negative environmental and biological effects. PMID:23207704

  11. Megascours: the morphodynamics of large river confluences

    NASA Astrophysics Data System (ADS)

    Dixon, Simon; Sambrook Smith, Greg; Nicholas, Andrew; Best, Jim; Bull, Jon; Vardy, Mark; Goodbred, Steve; Haque Sarker, Maminul

    2015-04-01

    River confluences are wildly acknowledged as crucial controlling influences upon upstream and downstream morphology and thus landscape evolution. Despite their importance very little is known about their evolution and morphodynamics, and there is a consensus in the literature that confluences represent fixed, nodal points in the fluvial network. Confluences have been shown to generate substantial bed scours around five times greater than mean depth. Previous research on the Ganges-Jamuna junction has shown large river confluences can be highly mobile, potentially 'combing' bed scours across a large area, although the extent to which this is representative of large confluences in general is unknown. Understanding the migration of confluences and associated scours is important for multiple applications including: designing civil engineering infrastructure (e.g. bridges, laying cable, pipelines, etc.), sequence stratigraphic interpretation for reconstruction of past environmental and sea level change, and in the hydrocarbon industry where it is crucial to discriminate autocyclic confluence scours from widespread allocyclic surfaces. Here we present a wide-ranging global review of large river confluence planforms based on analysis of Landsat imagery from 1972 through to 2014. This demonstrates there is an array of confluence morphodynamic types: from freely migrating confluences such as the Ganges-Jamuna, through confluences migrating on decadal timescales and fixed confluences. Along with data from recent geophysical field studies in the Ganges-Brahmaputra-Meghna basin we propose a conceptual model of large river confluence types and hypothesise how these influence morphodynamics and preservation of 'megascours' in the rock record. This conceptual model has implications for sequence stratigraphic models and the correct identification of surfaces related to past sea level change. We quantify the abundance of mobile confluence types by classifying all large confluences in the Amazon and Ganges-Brahmaputra-Meghna basins, showing these two basins have contrasting confluence morphodynamics. For the first time we show large river confluences have multiple scales of planform adjustment with important implications for infrastructure and interpretation of the rock record.

  12. Risk assessment of mercury in Alta Floresta. Amazon Basin - Brazil

    Microsoft Academic Search

    S. Hacon; E. R. Rochedo; R. Campos; G. Rosales

    1997-01-01

    In the last 15 years gold mining activity has been the main source of the mercury (Hg) emissions into the atmosphere in the\\u000a Amazon Basin. The first phase of gold production takes place in remote areas. In general the second one happens in the local\\u000a urban area, where the gold is commercialized and sent to the great economic centers. In

  13. Seasonal isoprene emission from a primary forest in central Amazon

    NASA Astrophysics Data System (ADS)

    Alves, E. G.; Jardine, K.; Yanez-Serrano, A. M.; Tota, J.

    2013-05-01

    Isoprene is emitted from many terrestrial plants at high rates, accounting for an estimated 1/3 of annual global volatile organic compound emissions from all anthropogenic and biogenic sources combined. Isoprene has multiple effects on atmospheric chemistry, carbon balance and climate, and it is assumed by the research community that tropical forests provide most of the global isoprene budget. Unfortunately, the single largest source of isoprene in the global atmosphere, the Amazon Basin, has been poorly explored for seasonal isoprene emission patterns. In this study, we quantified vertical concentration gradients of isoprene within and above a primary rainforest in central Amazon - during the dry season, dry-to-wet transition season and wet season. Results showed that isoprene concentrations are higher within the canopy than near the ground and above the canopy and that vertical gradients have a strong diurnal and seasonal dependence. Isoprene concentrations are higher during dry season than during the wet season; the same behavior observed for ambient air temperature and short wave downward radiation (Fig. 1). This indicates that isoprene emission variability is driven by seasonal variation in light and temperature, emphasizing the role of thermal protection and the light dependence of isoprene. Our results provide the first in situ observations of seasonal isoprene concentration gradients in central Amazon, and suggest that this seasonal variation in isoprene concentration could be driven by variations in light and temperature. Moreover, these results also highlight the need of more observational studies on isoprene emissions with a focus on annual and interannual variations in the Amazon Rainforest. Figure 1: Seasonal pattern of precipitation (bars), air temperature (solid line - top) and short wave downward (dotted line), considering data from 1999 to 2009. Isoprene air concentration (solid line - bottom) from September 2010 to January 2011 at 40 m of height.

  14. Reserves Protect against Deforestation Fires in the Amazon

    PubMed Central

    Adeney, J. Marion; Christensen, Norman L.; Pimm, Stuart L.

    2009-01-01

    Background Reserves are the principal means to conserve forests and biodiversity, but the question of whether reserves work is still debated. In the Amazon, fires are closely linked to deforestation, and thus can be used as a proxy for reserve effectiveness in protecting forest cover. We ask whether reserves in the Brazilian Amazon provide effective protection against deforestation and consequently fires, whether that protection is because of their location or their legal status, and whether some reserve types are more effective than others. Methodology/Principal Findings Previous work has shown that most Amazonian fires occur close to roads and are more frequent in El Niño years. We quantified these relationships for reserves and unprotected areas by examining satellite-detected hot pixels regressed against road distance across the entire Brazilian Amazon and for a decade with 2 El Niño-related droughts. Deforestation fires, as measured by hot pixels, declined exponentially with increasing distance from roads in all areas. Fewer deforestation fires occurred within protected areas than outside and the difference between protected and unprotected areas was greatest near roads. Thus, reserves were especially effective at preventing these fires where they are known to be most likely to burn; but they did not provide absolute protection. Even within reserves, at a given distance from roads, there were more deforestation fires in regions with high human impact than in those with low impact. The effect of El Niño on deforestation fires was greatest outside of reserves and near roads. Indigenous reserves, limited-use reserves, and fully protected reserves all had fewer fires than outside areas and did not appear to differ in their effectiveness. Conclusions/Significance Taking time, regional factors, and climate into account, our results show that reserves are an effective tool for curbing destructive burning in the Amazon. PMID:19352423

  15. Simulation of the regional climatic impact of Amazon deforestation

    Microsoft Academic Search

    J. Lean; D. A. Warrilow

    1989-01-01

    THE Amazon basin contains about half of Earth's Tropical forest1. Population pressure and subsequent demands for crop production, timber and firewood have led to rapid deforestation. Quantitative estimates of the rate of deforestation from analysis of Landsat observations indicate that rates are increasing exponentially in many regions2,3, but the precise figures are not known4. Removal of the protection provided by

  16. Numerical study of circulation on the inner Amazon Shelf

    Microsoft Academic Search

    Roberto Fioravanti Carelli Fontes; Belmiro Mendes Castro; Robert C. Beardsley

    2008-01-01

    We studied the circulation on the coastal domain of the Amazon Shelf by applying the hydrodynamic module of the estuarine\\u000a and coastal ocean model and sediment transport. The first barotropic experiment aimed to explain the major bathymetric effects\\u000a on tides and those generated by anisotropy in sediment distribution. We analyzed the continental shelf response of barotropic\\u000a tides under realistic bottom

  17. Trichomoniasis in a Blue-Fronted Amazon Parrot (Amazona aestiva)

    Microsoft Academic Search

    Michael M. Garner; Faye C. Sturtevant

    1992-01-01

    A ten-week-old Blue-fronted Amazon parrot was presented for respiratory distress and weakness. While hospitalized, it began regurgitating. Microscopic examination of the regurgitated material revealed large numbers of Trichomonas spp. and yeasts. Theparrot responded clinically to treatment with metronidazole but died shortly after treatment was discontinued. Necropsy revealed a large caseous mass distal to the thoracic inlet, which invaded andpartially obstructed

  18. Reshaping text data for efficient processing on Amazon EC2

    Microsoft Academic Search

    Gabriela Turcu; Ian T. Foster; Svetlozar Nestorov

    2010-01-01

    Text analysis tools are nowadays required to process increasingly large corpora which are often organized as small files (abstracts, news articles, etc). Cloud computing offers a convenient, on-demand, pay-as-you-go computing environment for solving such problems. We investigate provisioning on the Amazon EC2 cloud from the user perspective, attempting to provide a scheduling strategy that is both timely and cost effective.

  19. Behaviour and biomarkers as tools to assess the acute toxicity of benzo(a)pyrene in the common prawn Palaemon serratus.

    PubMed

    Silva, Carlos; Oliveira, Cristiana; Gravato, Carlos; Almeida, Joana R

    2013-09-01

    Benzo(a)pyrene (BaP) is considered an important marine environmental contaminant, given its recognised environmental persistence and toxicity. However, its effects in marine crustaceans are poorly studied, namely the accumulation and sub-cellular effects that might be linked to behavioural alterations and may lead to ecologically relevant consequences. This study aims to investigate behavioural and physiological responses of the common prawn (Palaemon serratus) after acute exposure to BaP and infer the potential effects for the population in the wild. The applied approach included the evaluation of swimming performance after exposure, and several biochemical biomarkers involved in biotransformation, oxidative damage, energy production and levels of BaP-type compounds in tissues (eye, digestive gland and muscle) in a 96 h acute bioassay with exposure to BaP (16-4096 ?g/L). The objective was to establish a link between behaviour (swimming velocity) and biochemical responses in order to assess the ecological relevance of the effects induced by BaP in P. serratus and to select useful tools for environmental risk assessment. Results showed swimming velocity impairment (LOEC = 128 ?g/L), lipid peroxidation (LPO) induction (LOEC = 4096 ?g/L) and BaP-type compounds increase in eye (LOEC = 32 ?g/L), digestive gland and muscle (LOEC = 512 ?g/L) of prawn after exposure to BaP. This oxidative damage in lipids seems to be caused by the incapacity to activate detoxification and anti-oxidant enzymes, once glutathione-S-transferase (GST), catalase (CAT) and glutathione peroxidase (GPx) were not affected by the exposure. This could be also an explanation to the increased levels of BaP-type compounds observed in tissues. An inability to increase the activities of enzymes involved in the production of energy was also observed, which may help to explain the detoxification failure and consequent increased levels of lipid peroxidation. The inhibition of swimming velocity was negatively correlated with biochemical parameters, including the presence of BaP-type compounds in different tissues and LPO, and thus, these parameters might be used as ecologically relevant and early-warning tools to assess the effects of PAHs. This study also highlights the usefulness of the fixed wavelength fluorescence (FF) technique to quantify PAHs-type compounds in tissues as indicative of exposure of P. serratus to PAHs, namely the sensitivity of eyes, which might be used for monitoring purposes and in marine ecological risk assessment studies. PMID:23769336

  20. Mercury emissions from forest burning in southern Amazon

    NASA Astrophysics Data System (ADS)

    Michelazzo, Paula Albernaz Machado; Fostier, Anne Hélène; Magarelli, Gabriella; Santos, José Carlos; Carvalho, João Andrade de

    2010-05-01

    Several recent studies have indicated that forest fires are likely to re-emit important quantities of atmospherically deposited mercury (Hg) to the atmosphere. Although the Amazon forest accounts for approximately 25% of the world's total rainforest, few data are available about these emissions. The emissions of mercury from prescribed fires of two 4-ha plots of Amazon forest were investigated. Hg concentration and Hg burden were determined for vegetation, litter and soil before and after the fires. The data show that only Hg present in the aboveground vegetation and in the O-horizon was volatilised; no significant soil emission was observed. Before the fire, the Hg stored in the vegetation (logs, branches, leaves and litter) ranged from 3.7 to 4.0 g ha-1 while 1.8 g ha-1 was found in the O-horizon. The mass balance calculations of the present work indicate an average Hg emission of 3.5 g ha-1 due to forest fires, with 1.6 ha-1 originating from O-horizon and 1.9 from above ground vegetation. On the base of the average annual deforestation rate of the Brazilian Amazon between 2000 and 2008, an annual Hg emission of 6.7 Mg yr-1 was estimated.

  1. Impacts of Amazon deforestation on regional weather and climate extremes

    NASA Astrophysics Data System (ADS)

    Medvigy, D.; Walko, R. L.; Avissar, R.

    2010-12-01

    Recent deforestation projections estimate that 40% of the Amazon rainforest will be deforested by 2050. Many modeling studies have indicated that deforestation will reduce average rainfall in the Amazon. However, very few studies have investigated the potential for deforestation to change the frequency and intensity of extreme climate and weather events. To fill this gap in our understanding, we use a variable-resolution GCM to investigate how precipitation and temperature extremes throughout South America respond to deforestation. The model’s grid mesh is set up to cover South America and nearby oceans at mesoscale (25 km) resolution, and then to gradually coarsen and cover the rest of the world at 200 km resolution. This approach differs from the two most common current approaches: (1) to use a GCM with too coarse of a resolution to evaluate regional climate extremes, or (2) to use a regional atmospheric model that requires lateral boundary conditions from a GCM or reanalysis. We find that deforestation induces large changes in winter (June-July-August) climate throughout much of South America. Extreme cold events become much more common along the eastern slopes of the Andes. The largest changes were in the western Amazon and, surprisingly, in Argentina, far from the actual deforested area. We also find shifts in precipitation extremes, especially in September-October-November. Such changes in temperature and precipitation extremes have important consequences for agriculture, natural ecosystems, and human society.

  2. North Tropical Atlantic influence on western Amazon fire season variability

    NASA Astrophysics Data System (ADS)

    Fernandes, Katia; Baethgen, Walter; Bernardes, Sergio; DeFries, Ruth; DeWitt, David G.; Goddard, Lisa; Lavado, Waldo; Lee, Dong Eun; Padoch, Christine; Pinedo-Vasquez, Miguel; Uriarte, Maria

    2011-06-01

    The prevailing wet climate in the western Amazon is not favorable to the natural occurrence of fires. Nevertheless, the current process of clearing of humid forests for agriculture and cattle ranching has increased the vulnerability of the region to the spread of fires. Using meteorological stations precipitation and the Moderate Resolution Spectroradiometer (MODIS) Active-Fires (AF) during 2000-2009, we show that fire anomalies vary closely with July-August-September (JAS) precipitation variability as measured by the Standardized Precipitation Index (SPI). The precipitation variability is, in turn, greatly determined by sea surface temperature (SST) anomalies in the North Tropical Atlantic (NTA). We develop a linear regression model to relate local fire activity to an index of the NTA-SST. By using seasonal forecasts of SST from a coupled model, we are able to predict anomalous JAS fire activity as early as April. We applied the method to predict the severe 2010 JAS season, which indicated strongly positive seasonal fire anomalies within the 95% prediction confidence intervals in most western Amazon. The spatial distribution of predicted SPI was also in accordance with observed precipitation anomalies. This three months lead time precipitation and fire prediction product in the western Amazon could help local decision makers to establish an early warning systems or other appropriate course of action before the fire season begins.

  3. New products made with lignocellulosic nanofibers from Brazilian amazon forest

    NASA Astrophysics Data System (ADS)

    Bufalino, L.; Mendes, L. M.; Tonoli, G. H. D.; Rodrigues, A.; Fonseca, A.; Cunha, P. I.; Marconcini, J. M.

    2014-08-01

    The biodiversity of the Amazon forest is undoubtedly rich; hence there is considerable variety of plant fibers regarding their morphological, chemical and structural properties. The legal exploration of the Brazilian Amazon is based on sustainable management techniques, but the generation of a relevant amount of plant wastes still cant be avoided. The correct destination of such materials is a challenge that Brazilian companies have to face. In this context, the National Council of Science and Technology (CNPq) promoted the creation of investigation nets on sustainability of Brazilian agribusiness. The Brazilian Net on Lignocellulosic Composites and Nanocomposites was then created, with partnership between several national and international research institutions. Until the moment, the results showed that Amazon plant fibers that are discarded as residues have great potential to nanofiber production. Nanopapers with considerable high mechanical and physical strength, proper opacity and great crystalline index were produced by using a clean and simple mechanical method. Those materials are candidates to several uses such as packaging, substrates transparent conductive films, gas barrier films, solar cells and e-papers.

  4. Virtual River

    NSDL National Science Digital Library

    Gary Novak

    2000-01-01

    This site has two interactive exercises designed to help students learn about river processes like discharge, flooding, and flood frequency. Each activity requires you to make careful observations and measurements, do simple calculations, and answer questions about your work. An interactive feedback and answer checking function is employed as one moves through the activities. A Certificate of Completion is available at the end of each activity.

  5. River sediments.

    PubMed

    Williams, Martin

    2012-05-13

    River history is reflected in the nature of the sediments carried and deposited over time. Using examples drawn from around the world, this account illustrates how river sediments have been used to reconstruct past environmental changes at a variety of scales in time and space. Problems arising from a patchy alluvial record and from influences external to the river basin can make interpretation difficult. The Nile is treated in some detail because its history is further complicated by tectonic, volcanic and climatic events in its headwaters and by enduring human impacts. It arose soon after 30 Ma. Since that time approximately 100,000 km(3) of rock have been eroded from its Ethiopian sources and deposited in the eastern Mediterranean, with minor amounts of sediment laid down along its former flood plains in Egypt and Sudan. From these fragmentary alluvial remains, a detailed history of Nile floods and droughts has been reconstructed for the last 15 kyr, and, with less detail, for the past 150 kyr, which shows strong accordance with global fluctuations in the strength of the summer monsoon, which are in turn perhaps modulated by changes in solar insolation caused by changes in the Earth's orbit and by variations in solar irradiance. PMID:22474677

  6. Annual CO2 flux Across Moisture and Vegetation Gradients in the Amazon.

    NASA Astrophysics Data System (ADS)

    Baker, I. T.; Prihodko, L.; Denning, A. S.

    2007-12-01

    The Amazon region is important to global climate both due to its large size and the large fluxes of energy, moisture and carbon exchanged there between the atmosphere and terrestrial biosphere. The spatial extent and large flux magnitude in the region firmly couple both the global circulation of the atmosphere and carbon flux to the region. Landsurface models have a poor record for simulating the annual cycle of exchange of carbon in the Amazon basin. In general, models have predicted uptake of carbon during the wet season and efflux during dry months, while observations show the opposite. Observational research has suggested a number of biogeophysical mechanisms to explain all or part of this annual cycle, including: 1) increased canopy phenological response to increased insolation during dry season 2) ability of deep roots to maintain transpiration as surface soil dries 3) Hydraulic redistribution of soil moisture by roots to bring deep water to surface. Using the Simple Biosphere model we were able to show that a control simulation has an erroneous response consistent with previous modeling efforts. We were also able to show that, when the above mechanisms were included in the model physics, a much more realistic simulation of the annual cycle of CO2 flux (NEE) at the Tapajos River km83 site was possible. We now conduct a regional analysis across 8 tower sites throughout Amazonia across multiple climactic regimes. Annual precipitation ranges from less than 1000 mm to more than 2000 mm, and length of dry season (defined as a month with <100 mm precipitation) ranges from none to 6 months or more. Vegetation types consist of tropical forest, pasture, and savanna. We find that by including the aforementioned mechanisms into the model we remove stress and obtain more reasonable annual cycles of NEE in the forest sites, but in the pasture and savanna sites the modified model removes vegetation stress in an unrealistic manner. Regional simulations require realistic input information on soil and rooting depth to perform realistically when confronted with data. When we include these data in the simulations the model carbon flux is comparable to observed across moisture and vegetation gradients in Amazonia.

  7. Molecular characterization of an earliest cacao (Theobroma cacao L.) collection from Peruvian Amazon using microsatllite DNA markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cacao (Theobroma cacao L.) is indigenous to the Amazon region of South America. The Peruvian Amazon harbors a large number of diverse cacao populations. Since the 1930s, several numbers of populations have been collected from the Peruvian Amazon and maintained as ex situ germplasm repositories in ...

  8. Wilson Bull., 110(3), 1998, pp. 352-361 VOCALIZATIONS OF THE BLUE-FRONTED AMAZON

    E-print Network

    Fernández-Juricic, Esteban

    Wilson Bull., 110(3), 1998, pp. 352-361 VOCALIZATIONS OF THE BLUE-FRONTED AMAZON (AMAZONA AESTIVA. ALVAREZ2 ABSTRACT.-The calls of the Blue-fronted Amazon (Amazona aestiva) are described and their possible-fronted Amazon (Amazona aes- tiva) is a parrot whose distribution extends over northeastern Brazil, Bolivia

  9. Leaf wax biomarkers in transit record river catchment composition

    NASA Astrophysics Data System (ADS)

    Ponton, Camilo; West, A. Joshua; Feakins, Sarah J.; Galy, Valier

    2014-09-01

    Rivers carry organic molecules derived from terrestrial vegetation to sedimentary deposits in lakes and oceans, storing information about past climate and erosion, as well as representing a component of the carbon cycle. It is anticipated that sourcing of organic matter may not be uniform across catchments with substantial environmental variability in topography, vegetation zones, and climate. Here we analyze plant leaf wax biomarkers in transit in the Madre de Dios River (Peru), which drains a forested catchment across 4.5 km of elevation from the tropical montane forests of the Andes down into the rainforests of Amazonia. We find that the hydrogen isotopic composition of leaf wax molecules (specifically the C28 n-alkanoic acid) carried by this tropical mountain river largely records the elevation gradient defined by the isotopic composition of precipitation, and this supports the general interpretation of these biomarkers as proxy recorders of catchment conditions. However, we also find that leaf wax isotopic composition varies with river flow regime over storm and seasonal timescales, which could in some cases be quantitatively significant relative to changes in the isotopic composition of precipitation in the past. Our results inform on the sourcing and transport of material by a major tributary of the Amazon River and contribute to the spatial interpretation of sedimentary records of past climate using the leaf wax proxy.

  10. River barriers and cryptic biodiversity in an evolutionary museum.

    PubMed

    Voelker, G; Marks, B D; Kahindo, C; A'genonga, U; Bapeamoni, F; Duffie, L E; Huntley, J W; Mulotwa, E; Rosenbaum, S A; Light, J E

    2013-03-01

    The Riverine Barriers Hypothesis (RBH) posits that tropical rivers can be effective barriers to gene flow, based on observations that range boundaries often coincide with river barriers. Over the last 160 years, the RBH has received attention from various perspectives, with a particular focus on vertebrates in the Amazon Basin. To our knowledge, no molecular assessment of the RBH has been conducted on birds in the Afrotropics, despite its rich avifauna and many Afrotropical bird species being widely distributed across numerous watersheds and basins. Here, we provide the first genetic evidence that an Afrotropical river has served as a barrier for birds and for their lice, based on four understory bird species collected from sites north and south of the Congo River. Our results indicate near-contemporaneous, Pleistocene lineage diversification across the Congo River in these species. Our results further indicate differing levels of genetic variation in bird lice; the extent of this variation appears linked to the life-history of both the host and the louse. Extensive cryptic diversity likely is being harbored in Afrotropical forests, in both understory birds and their lice. Therefore, these forests may not be "museums" of old lineages. Rather, substantial evolutionary diversification may have occurred in Afrotropical forests throughout the Pleistocene, supporting the Pleistocene Forest Refuge Hypothesis. Strong genetic variation in birds and their lice within a small part of the Congo Basin forest indicates that we may have grossly underestimated diversity in the Afrotropics, making these forests home of substantial biodiversity in need of conservation. PMID:23532272

  11. How important and different are tropical rivers? - An overview

    NASA Astrophysics Data System (ADS)

    Syvitski, James P. M.; Cohen, Sagy; Kettner, Albert J.; Brakenridge, G. Robert

    2014-12-01

    Tropical river systems, wherein much of the drainage basin experiences tropical climate are strongly influenced by the annual and inter-annual variations of the Inter-tropical Convergence Zone (ITCZ) and its derivative monsoonal winds. Rivers draining rainforests and those subjected to tropical monsoons typically demonstrate high runoff, but with notable exceptions. High rainfall intensities from burst weather events are common in the tropics. The release of rain-forming aerosols also appears to uniquely increase regional rainfall, but its geomorphic manifestation is hard to detect. Compared to other more temperate river systems, climate-driven tropical rivers do not appear to transport a disproportionate amount of particulate load to the world's oceans, and their warmer, less viscous waters are less competent. Tropical biogeochemical environments do appear to influence the sedimentary environment. Multiple-year hydrographs reveal that seasonality is a dominant feature of most tropical rivers, but the rivers of Papua New Guinea are somewhat unique being less seasonally modulated. Modeled riverine suspended sediment flux through global catchments is used in conjunction with observational data for 35 tropical basins to highlight key basin scaling relationships. A 50 year, daily model simulation illuminates how precipitation, relief, lithology and drainage basin area affect sediment load, yield and concentration. Local sediment yield within the Amazon is highest near the Andes, but decreases towards the ocean as the river's discharge is diluted by water influxes from sediment-deprived rainforest tributaries. Bedload is strongly affected by the hydraulic gradient and discharge, and the interplay of these two parameters predicts foci of net bedload deposition or erosion. Rivers of the tropics have comparatively low inter-annual variation in sediment yield.

  12. The gene encoding the nucleocapsid protein of Gill-associated nidovirus of Penaeus monodon prawns is located upstream of the glycoprotein gene.

    PubMed

    Cowley, Jeff A; Cadogan, Lee C; Spann, Kirsten M; Sittidilokratna, Nusra; Walker, Peter J

    2004-08-01

    The ORF2 gene of Gill-associated virus (GAV) of Penaeus monodon prawns resides 93 nucleotides downstream of the ORF1a-ORF1b gene and encodes a 144-amino-acid hydrophilic polypeptide (15,998 Da; pI, 9.75) containing 20 basic (14%) and 13 acidic (9%) residues and 19 prolines (13%). Antiserum to a synthetic ORF2 peptide or an Escherichia coli-expressed glutathione S-transferase-ORF2 fusion protein detected a 20-kDa protein in infected lymphoid organ and gill tissues in Western blots. The GAV ORF2 fusion protein antiserum also cross-reacted with the p20 nucleoprotein in virions of the closely related Yellow head virus. By immuno-gold electron microscopy, it was observed that the ORF2 peptide antibody localized to tubular GAV nucleocapsids, often at the ends or at lateral cross sections. As GAV appears to contain only two structural protein genes (ORF2 and ORF3), these data indicate that GAV differs from vertebrate nidoviruses in that the gene encoding the nucleocapsid protein is located upstream of the gene encoding the virion glycoproteins. PMID:15280504

  13. Atmospheric corrosion tests in Brazilian Legal Amazon - field and laboratory tests

    Microsoft Academic Search

    L. R. M. Miranda; L. Sathler; R. Nogueira; S. L. D. C. Brasil

    2000-01-01

    This paper presents the first results concerning tests carried out to evaluate the atmospheric corrosion in Brazilian Legal Amazon, as part of the SIVAM - Amazon Surveillance System. The aim of the present work is to determine and select materials as well as anti-rust paints, which will be employed to protect metallic structures of radar towers, equipment and buildings. Five

  14. SPATIO-TEMPORAL REGRESSION MODELS FOR DEFORESTATION IN THE BRAZILIAN AMAZON Giovana M. de Espindolaa

    E-print Network

    Camara, Gilberto

    SPATIO-TEMPORAL REGRESSION MODELS FOR DEFORESTATION IN THE BRAZILIAN AMAZON Giovana M. de change, spatial simultaneous autoregression ABSTRACT: Deforestation in the Brazilian Amazon has sharply of deforestation in a selected area by relating data from 2002-2008 to a number of explanatory variables, part

  15. Fractally deforested landscape: Pattern and process in a tri-national Amazon frontier

    E-print Network

    Fractally deforested landscape: Pattern and process in a tri-national Amazon frontier Jing Sun a 32611, USA Keywords: Amazon Deforestation Fractal analysis Fixed-grid scans Bottom-up plan Configuration of deforestation at a pixel level from 1986 to 2010 in the study region. The evolving pattern of development

  16. Gender-specific out-migration, deforestation and urbanization in the Ecuadorian Amazon

    E-print Network

    Lopez-Carr, David

    Gender-specific out-migration, deforestation and urbanization in the Ecuadorian Amazon Alisson F rates of deforestation of any Amazonian nation. Most of this forest elimination has been caused on deforestation, urbanization and regional development, population mobility within the Amazon has hardly been

  17. Decrease of soil fertility and release of mercury following deforestation in the Andean Amazon,

    E-print Network

    Long, Bernard

    Decrease of soil fertility and release of mercury following deforestation in the Andean Amazon erosion and degradation provoked by deforestation in the Amazon is a global concern, and recent studies propose a link between deforestation, soil erosion and the leaching of naturally occurring mercury (Hg

  18. Diameter increment and growth patterns for individual tree growing in Central Amazon, Brazil

    E-print Network

    Chambers, Jeff

    Diameter increment and growth patterns for individual tree growing in Central Amazon, Brazil, Niro Higuchi* INPA, Tropical Forestry Department, National Institute for Amazon Research, Caixa Postal primarily to: (i) select tree species for logging; (ii) selecting tree species for protection; (iii

  19. Conversion of the Amazon rainforest to agriculture results in biotic homogenization of soil

    E-print Network

    Bohannan, Brendan

    Conversion of the Amazon rainforest to agriculture results in biotic homogenization of soil Contributed by James M. Tiedje, November 29, 2012 (sent for review August 8, 2012) The Amazon rainforest rainforest, but in a manner different from plants and animals. Local taxonomic and phyloge- netic diversity

  20. Amazon rainforests green-up with sunlight in dry season Alfredo R. Huete,1,2

    E-print Network

    Saleska, Scott

    Amazon rainforests green-up with sunlight in dry season Alfredo R. Huete,1,2 Kamel Didan,1 Yosio E March 2006. [1] Metabolism and phenology of Amazon rainforests significantly influence global dynamics measured from eddy flux towers in both a rainforest and forest conversion site confirm our interpretation

  1. Biogeography of the Amazon molly, Poecilia Ingo Schlupp1,2

    E-print Network

    Schlupp, Ingo

    , unisexuality, Poecilia latipinna, Poecilia mexicana. INTRODUCTION The study of biogeography has contributedBiogeography of the Amazon molly, Poecilia formosa Ingo Schlupp1,2 *, Jakob Parzefall1 and ManfredÈrzburg, D - 97074 WuÈrzburg, Germany Abstract Aim The unisexual Amazon molly (Poecilia formosa) is a clonal

  2. Estimation of damage to human health due to forest burning in the Amazon

    Microsoft Academic Search

    Mário Jorge Cardoso de Mendonça; Adolfo Sachsida; Paulo R. A. Loureiro

    2006-01-01

    Forest burning stands as a highly used practice in the Brazilian Amazon Forest. Burning trees is the cheapest way to expand agricultural frontiers in the Amazon region. Nevertheless, the smoke generated in this process can produce undesirable negative effects, in particular health-induced problems by the polluted air. This study aims to investigate whether these effects on the health of the

  3. Electrocardiogram of the African grey (psittacus erithacus) and Amazon (Amazona spp.) parrot

    Microsoft Academic Search

    A. M. P. Nap; J. T. Lumeij; A. A. Stokhof

    1992-01-01

    Electrocardiographic reference values and configurations were established in apparently healthy African grey (Psittacus erithacus; n=45) and Amazon (Amazona spp.; n = 37) parrots, using standard limb leads. In 31 of the African grey parrots and 32 of the Amazon parrots electrocardiograms were made during isoflurane?anaesthesia. Significant differences between anaesthetized and unanaesthetized birds were found only for the median heart rate

  4. Vibrio cholerae O1 from superficial water of the Tucunduba Stream, Brazilian Amazon.

    PubMed

    Sá, L L C; Vale, E R V; Garza, D R; Vicente, A C P

    2012-04-01

    Isolation and genetic characterization of an environmental Vibrio cholerae O1 from the Amazon is reported. This strain lacks two major virulence factors - CTX and TCP - but carries other genes related to virulence. Genetic similarity with epidemic strains is evaluated and the importance of V. cholerae surveillance in the Amazon is emphasized. PMID:24031874

  5. A Performance and Cost Analysis of the Amazon Elastic Compute Cloud (EC2) Cluster Compute Instance

    E-print Network

    Bjørnstad, Ottar Nordal

    A Performance and Cost Analysis of the Amazon Elastic Compute Cloud (EC2) Cluster Compute Instance the availability of Elastic Compute Cloud (EC2) Cluster Compute Instances specifically designed for high compute power available on demand the question arises if cloud computing with using and Amazon EC2 HPC

  6. Atmospheric water balance in the Amazon basin: An isotopic evapotranspiration model

    Microsoft Academic Search

    J. R. Gat; E. Matsui

    1991-01-01

    An increase of 3% in the ``d'' value of the isotopic composition of precipitation over the Amazon Basin suggests that an isotopically fractionated evapotranspiration flux contributes to the atmospheric water balance over the region. A steady state evapotranspiration model for the Amazon Basin was developed, and it is shown that the observed increase in the ``d'' value corresponds to a

  7. 1. Background What is the fate of the Amazon under climate change?

    E-print Network

    Saleska, Scott

    -induced drought (Markewitz et al., 2010; Brando et al., 2008) Venezuela 1 0 ° 1 0 ° Amazon forests Mean annual $ $ $$$ $ $ $ JAV K34 K77 RJA FNS K67 K83 CAX Colombia Venezuela Guyana Surinam French Guyana Brasil Peru Ecuador 1" of the Amazon forest:forest: p p y driver of current tropical deforestation) 2 Climate change drought Evapo

  8. Degradation of forests through logging and fire in the eastern Brazilian Amazon

    Microsoft Academic Search

    Jeffrey J. Gerwinga

    The status of tropical forests in the Amazon basin is often expressed in terms of deforestation extent. However, in the eastern Brazilian Amazon logging and ground fires degrade forest structure and create land cover types that are intermediate between intact and cleared forest. The objective of this study was to provide a basis for understanding the implications of forest degradation

  9. Future drying of the southern Amazon5 and central Brazil6

    E-print Network

    Zeng, Ning

    1 1 2 3 4 Future drying of the southern Amazon5 and central Brazil6 7 8 Brian Cook1 , Ning Zeng1 processes. Firstly, a decline in precipitation of 24% in the29 southern Amazon's dry season reduces soil, further reducing soil moisture. The drying corresponds to a lengthening36 of the dry season by 11 days

  10. YELLOWSTONE RIVER WATCH (YRW)

    EPA Science Inventory

    Yellowstone River Watch seeks to expand its monitoring and education efforts throughout the Yellowstone River Basin by actively recruiting and training new teacher members. Yellowstone River Watch also seeks to advance existing school programs by offering quality assurance/quali...

  11. Acute Conjunctivitis with Episcleritis and Anterior Uveitis Linked to Adiaspiromycosis and Freshwater Sponges, Amazon Region, Brazil, 2005

    PubMed Central

    Moraes, Mario A.P.; Renoiner, Ernesto I.M.; Dantas, Marta H.P.; Lanzieri, Tatiania M.; Fonseca, Carlos F.; Luna, Expedito J.A.; Hatch, Douglas L.

    2009-01-01

    We conducted an epidemiologic investigation of an outbreak of ocular disease among children to determine whether the disease was linked to Emmonsia sp., a rarely-reported fungus and an agent of adiaspiromycosis. Using an unmatched case–control study design, we compared case-patients with asymptomatic controls randomly selected from the population. Scleral biopsies were analyzed microscopically. Of 5,084 children examined, 99 case-patients were identified; mean age (+1 SD) was 11.0 ± 4.4 years. Symptoms included photophobia (57%), ocular pain (42%), and blurred vision (40%). In the multivariate analysis, risk factors included diving in the Araguaia River (odds ratio 5.2; 95% confidence interval 2.4–12.0). Microscopy identified foreign bodies consistent with adiaconidia. This outbreak probably resulted from foreign-body–type reactions to adiaspiromycosis conidia after initial irritation caused by conjunctival contact with spicules of sponges in the river. Symptomatic children responded to corticosteroid treatment. Adiaspiromycosis is a preventable cause of ocular disease in the Amazon region. PMID:19331759

  12. River Network Online

    NSDL National Science Digital Library

    1999-01-01

    The mission of River Network, a non-governmental organization, is "to help people organize to protect and restore rivers and watersheds." To that end, the River Network homepage offers a wealth of information and links on rivers and watersheds including publications, upcoming conferences, watershed protection issues, river conservation job listings, related organizations, and a searchable National Directory of River and Watershed Organizations. The What's New section announces recent publications, events, and ongoing important river/watershed issues. For anyone interested in learning about or participating in River/Watershed initiatives, this is an excellent resource.

  13. The National Rivers Website

    NSDL National Science Digital Library

    The National Organization for Rivers sponsors this page and provides information on water-based recreation and conservation. They are building a River Registry to provide an overview of rivers in each state as well as around the world. The registry includes physical characteristics, recreation opportunities and legal and policy information. The Who Owns the Rivers section provides a bibliography of river-related case law, information on river navigation history and a discussion component called Ask the Attorney. The site also includes information about the U.S. River Conservation Team and guidance for individuals to contribute to river protection efforts. Videos and books are for sale as well.

  14. Technical and Institutional Innovation in Agroforestry for Protected Areas Management in the Brazilian Amazon: Opportunities and Limitations

    NASA Astrophysics Data System (ADS)

    Schroth, Götz; da Mota, Maria do Socorro S.

    2013-08-01

    Tropical forest countries are struggling with the partially conflicting policy objectives of socioeconomic development, forest conservation, and safeguarding the livelihoods of local forest-dependent people. We worked with communities in the lower Tapajós region of the central Brazilian Amazon for over 10 years to understand their traditional and present land use practices, the constraints, and decision making processes imposed by their biophysical, socioeconomic, and political environment, and to facilitate development trajectories to improve the livelihoods of forest communities while conserving the forest on the farms and in the larger landscape. The work focused on riverine communities initially in the Tapajós National Forest and then in the Tapajós-Arapiuns Extractive Reserve. These communities have a century-old tradition of planting rubber agroforests which despite their abandonment during the 1990s still widely characterize the vegetation of the river banks, especially in the two protected areas where they are safe from the recent expansion of mechanized rice and soybean agriculture. The project evolved from the capacity-building of communities in techniques to increase the productivity of the rubber agroforests without breaking their low-input and low-risk logic, to the establishment of a community enterprise that allowed reserve inhabitants to reforest their own land with tree species of their choice and sell reforestation (not carbon) credits to local timber companies while retaining the ownership of the trees. By making land use practices economically more viable and ecologically more appropriate for protected areas, the project shows ways to strengthen the system of extractive and sustainable development reserves that protects millions of hectares of Amazon forest with the consent of the communities that inhabit them.

  15. Technical and institutional innovation in agroforestry for protected areas management in the Brazilian Amazon: opportunities and limitations.

    PubMed

    Schroth, Götz; da Mota, Maria do Socorro S

    2013-08-01

    Tropical forest countries are struggling with the partially conflicting policy objectives of socioeconomic development, forest conservation, and safeguarding the livelihoods of local forest-dependent people. We worked with communities in the lower Tapajós region of the central Brazilian Amazon for over 10 years to understand their traditional and present land use practices, the constraints, and decision making processes imposed by their biophysical, socioeconomic, and political environment, and to facilitate development trajectories to improve the livelihoods of forest communities while conserving the forest on the farms and in the larger landscape. The work focused on riverine communities initially in the Tapajós National Forest and then in the Tapajós-Arapiuns Extractive Reserve. These communities have a century-old tradition of planting rubber agroforests which despite their abandonment during the 1990s still widely characterize the vegetation of the river banks, especially in the two protected areas where they are safe from the recent expansion of mechanized rice and soybean agriculture. The project evolved from the capacity-building of communities in techniques to increase the productivity of the rubber agroforests without breaking their low-input and low-risk logic, to the establishment of a community enterprise that allowed reserve inhabitants to reforest their own land with tree species of their choice and sell reforestation (not carbon) credits to local timber companies while retaining the ownership of the trees. By making land use practices economically more viable and ecologically more appropriate for protected areas, the project shows ways to strengthen the system of extractive and sustainable development reserves that protects millions of hectares of Amazon forest with the consent of the communities that inhabit them. PMID:23636205

  16. Dietary supplement of banana (Musa acuminata) peels hot-water extract to enhance the growth, anti-hypothermal stress, immunity and disease resistance of the giant freshwater prawn, Macrobrachium rosenbergii.

    PubMed

    Rattanavichai, Wutti; Cheng, Winton

    2015-04-01

    In the present study, Macrobrachium rosenbergii were fed with diets containing extracts of banana, Musa acuminate, fruit's peel (banana peels extract, BPE) at 0, 1.0, 3.0 and 6.0 g kg(-1). The non-specific immune parameters, disease resistance and anti-hypothermal stress were evaluated at 2, 4, 8, 16 and 32 days of post feeding. Also, we demonstrated the percent weight gain (PWG), percent length gain (PLG), feeding efficiency (FE), and survival rate of giant freshwater prawn at 30, 60, 90, and 120 days of post feeding. The PWG, PLG, FE and survival rate of prawns fed at 0, 1.0, 3.0 and 6.0 g kg(-1) BPE-containing diets after 120 days were 69.5%, 75.4%, 77.8% and 83.3%; 21.8%, 23.6%, 27.8% and 33.9%; 0.60, 0.72, 0.75 and 0.90; and 55.4%, 62.2%, 62.3% and 75.3%, respectively. After 32 days of post feeding, a significant increase in total haemocyte count (THC), different haemocyte count (DHC), respiratory bursts (RBs), superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, phenoloxidase (PO) activity and transglutaminase (TG) activity, and meanwhile, a decreased haemolymph coagulation time was observed. Furthermore, phagocytic activity and clearance efficiency of prawns against Lactococcus garvieae infection were significantly increased. Prawns challenged with L. garvieae after 32 days of feeding at 1.0, 3.0 and 6.0 g kg(-1) had a significantly higher survival rate (33.3%, 40.0% and 56.7%) than those fed with the control diet. Subsequently, hypothermal (14 °C) stress was 43.4%, 50.0% and 50.0%, respectively. Altogether, we therefore recommend the dietary BPE administration at 6.0 g kg(-1) promotes growth, anti-hypothermal stress, and enhance immunity and resistance against L. garvieae in M. rosenbergii. PMID:25634258

  17. Climatic impact of Amazon deforestation - a mechanistic model study

    SciTech Connect

    Ning Zeng; Dickinson, R.E.; Xubin Zeng [Univ. of Arizona, Tucson, AZ (United States)] [Univ. of Arizona, Tucson, AZ (United States)

    1996-04-01

    Recent general circulation model (GCM) experiments suggest a drastic change in the regional climate, especially the hydrological cycle, after hypothesized Amazon basinwide deforestation. To facilitate the theoretical understanding os such a change, we develop an intermediate-level model for tropical climatology, including atmosphere-land-ocean interaction. The model consists of linearized steady-state primitive equations with simplified thermodynamics. A simple hydrological cycle is also included. Special attention has been paid to land-surface processes. It generally better simulates tropical climatology and the ENSO anomaly than do many of the previous simple models. The climatic impact of Amazon deforestation is studied in the context of this model. Model results show a much weakened Atlantic Walker-Hadley circulation as a result of the existence of a strong positive feedback loop in the atmospheric circulation system and the hydrological cycle. The regional climate is highly sensitive to albedo change and sensitive to evapotranspiration change. The pure dynamical effect of surface roughness length on convergence is small, but the surface flow anomaly displays intriguing features. Analysis of the thermodynamic equation reveals that the balance between convective heating, adiabatic cooling, and radiation largely determines the deforestation response. Studies of the consequences of hypothetical continuous deforestation suggest that the replacement of forest by desert may be able to sustain a dry climate. Scaling analysis motivated by our modeling efforts also helps to interpret the common results of many GCM simulations. When a simple mixed-layer ocean model is coupled with the atmospheric model, the results suggest a 1{degrees}C decrease in SST gradient across the equatorial Atlantic Ocean in response to Amazon deforestation. The magnitude depends on the coupling strength. 66 refs., 16 figs., 4 tabs.

  18. Distribution of Aboveground Live Biomass in the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Saatchi, S. S.; Houghton, R. A.; DosSantos Alvala, R. C.; Soares, J. V.; Yu, Y.

    2007-01-01

    The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old-growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300Mgha(sup 1) here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300Mgha(sup 1). Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200Mgha(sup 1). The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and below ground biomass, is 86 PgC with +/- 20% uncertainty.

  19. Socioeconomic drivers of deforestation in the Northern Ecuadorian Amazon.

    PubMed

    Mena, Carlos F; Bilsborrow, Richard E; McClain, Michael E

    2006-06-01

    Investigations of land use/land cover (LULC) change and forest management are limited by a lack of understanding of how socioeconomic factors affect land use. This lack also constrains the predictions of future deforestation, which is especially important in the Amazon basin, where large tracts of natural forest are being converted to managed uses. Research presented in this article was conducted to address this lack of understanding. Its objectives are (a) to quantify deforestation in the Northern Ecuadorian Amazon (NEA) during the periods 1986-1996 and 1996-2002; and (b) to determine the significance and magnitude of the effects of socioeconomic factors on deforestation rates at both the parroquia (parish) and finca (farm) levels. Annual deforestation rates were quantified via satellite image processing and geographic information systems. Linear spatial lag regression analyses were then used to explore relationships between socioeconomic factors and deforestation. Socioeconomic factors were obtained, at the finca level, from a detailed household survey carried out in 1990 and 1999, and at the parroquia level from data in the 1990 and 2001 Ecuadorian censuses of population. We found that the average annual deforestation rate was 2.5% and 1.8%/year for 1986-1996 and 1996-2002, respectively. At the parroquia level, variables representing demographic factors (i.e., population density) and accessibility factors (i.e., road density), among others, were found to be significantly related to deforestation. At the farm level, the factors related to deforestation were household size, distance by road to main cities, education, and hired labor. The findings of this research demonstrate both the severity of deforestation in the Northern Ecuadorian Amazon and the array of factors affecting deforestation in the tropics. PMID:16555027

  20. Characterizing the Role of Lake Storage Dynamics in the Congo River Basin

    NASA Astrophysics Data System (ADS)

    Raoufi, R.; Beighley, E., II; Lee, H.; Alsdorf, D. E.

    2014-12-01

    Although the Congo River is the world's second largest, behind the Amazon, in terms of annual discharge and rain forest extent, our level of hydrologic understanding is somewhat limited largely due to a lack of in-situ measurements. This point is even more important in the context of how large tropical wetlands impact global hydrologic and carbon cycles. For example, although the Amazon and Congo are both large tropical rivers, their wetlands appear to function differently. The Congo River is also unique in that it is the only major river to cross the equator twice, which results in a year-round rainfall from the movement of the Inter Tropical Convergence Zone (ITCZ). To better understand how the Congo River wetlands function and their role in global carbon cycle, we first characterize the spatial and temporal distribution of water stores and fluxes throughout the basin. Given the limited in-situ measurements, a combination of modeling and remotely sensed measurements are used. Here, we specifically focus on the role of lake storage dynamics in the Congo River discharge. The Hillslope River Routing (HRR) hydrologic model, Tropical Rainfall Measuring Mission (TRMM) precipitation (3B42v7), Moderate Resolution Imaging Spectroradiometer (MODIS) albedo ( MCD43C3), leaf area index (MCD15A2), land surface temperature (MOD11C1 and MYD11C1) and land cover (MCD12C1), water level changes from radar altimetry, and LandSat based extent measurements over major water bodies are used to estimate basin-wide total water storage variations. The HRR model results, which include hourly water dynamics for the Congo and surrounding basins for the period 2002-2012, are also compared to NASA's Gravity Recovery and Climate Experiment (GRACE) measurements in order to assess the impact of GRACE signal leakage over the Congo Basin.

  1. Seasonal and spatial contrasts of sedimentary organic carbon in floodplain lakes of the central Amazon basin.

    NASA Astrophysics Data System (ADS)

    Sobrinho, Rodrigo; Kim, Jung-Hyun; Abril, Gwenaël; Zell, Claudia; Moreira-Turcq, Patricia; Mortillaro, Jean-Michel; Meziane, Tarik; Damsté, Jaap; Bernardes, Marcelo

    2014-05-01

    Three-quarters of the area of flooded land in the world are temporary wetlands (Downing, 2009), which play a significant role in the global carbon cycle(Einsele et al., 2001; Cole et al., 2007; Battin et al., 2009; Abril et al., 2013). Previous studies of the Amazonian floodplain lakes (várzeas), one important compartment of wetlands, showed that the sedimentation of organic carbon (OC) in the floodplain lakes is strongly linked to the periodical floods and to the biogeography from upstream to downstream(Victoria et al., 1992; Martinelli et al., 2003). However, the main sources of sedimentary OC remain uncertain. Hence, the study of the sources of OC buried in floodplain lake sediments can enhance our understanding of the carbon balance of the Amazon ecosystems. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverage. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as C:N ratio and stable isotopic composition of organic carbon (?13COC). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus (Hedges and Ertel, 1982) and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the soil OC from land to the aquatic settings (Hopmans et al., 2004). Our data showed that during the RW and FW seasons, the concentration of lignin and brGDGTs were higher in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of a mixture of C3 plant detritus and soil OC. However, a downstream increase in C4 plant-derived OC contribution was observed along the gradient of increasingly open waters, i.e. from upstream to downstream. We also identify the OC contribution from the seasonally flooded forests, i.e. temporary wetlands as the most important source of sedimentary OC in floodplain lakes. Accordingly, we attribute temporal and spatial difference in sedimentary OC composition to the hydrological connectivity between the Amazon River and its floodplain lakes and thus between the surrounding forests and the floodplain lakes. References: Abril, G., J.-M.Martinez, Artigas, L.F., Moreira-Turcq, P., Benedetti, M.P., Vidal, L., Meziane, T., Kim, J.-H., Bernardes, M.C., Savoye, N., Deborde, J., Albéric, P., Souza, M.F.L., Souza, E.L., Roland, F. Amazon River carbon dioxide outgassing fuelled by wetlands. Nature accepted (2013). Battin, T.J., Luyssaert, S., Kaplan, L.A., Aufdenkampe, A.K., Richter, A., Tranvik, L.J., 2009. The boundless carbon cycle. Nature Geoscience 2, 598 - 600 (2009). Cole, J.J., Prairie, Y.T., Caraco, N.F., McDowell, W.H., Tranvik, L.J., Striegl, R.G., Duarte, C.M., Kortelainen, P., Downing, J.A., Middelburg, J.J., Melack, J. Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget. Ecosystems 10, 171 - 184 (2007). Downing, J. A. Global limnology: up-scaling aquatic services and processes to planet Earth. Verh Internat Verein Limnol 30, 1149.-1166 (2009). Einsele, G., Yan, J., Hinderer, M. Atmospheric carbon burial in modern lake basins and its significance for the global carbon budget. Global and Planetary Change 30, 167 - 195 (2001). Hedges, J.I., Ertel, J.R. Characterization of Lignin by Gas Capillary Chromatography of Cupric Oxide Oxidation Products. Analitical Chemistry 54, 174-178 (1982). Hopmans, E.C., Weijers, J.W.H., Schefu, E., Herfort, L., Damste, J.S.S., Schouten, S.,. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids. Earth and Planetary Science Letters 224, 107 - 116 (2004). Martinelli, L.A., Victoria, R.L., Camargo, P.B.d., Piccolo, M.d.C., Mertes, L., Richey, J.E., Devol, A.H., Forsberg, B.R.. Inland variability of carbon-nitrogen co

  2. The Green Ocean Over the Amazon: Implications for Cloud Electrification

    NASA Technical Reports Server (NTRS)

    Williams, E.; Blakeslee, R.; Boccippio, D.; Arnold, James E. (Technical Monitor)

    2001-01-01

    A convective regime with distinct maritime characteristics (weak updraft, low CCN, prevalent coalescence and rainout, weak mixed phase reflectivity, low glaciation temperature, and little if any lightning) is documented over the Amazon basin of the South American continent, and dubbed the "green ocean". Radar, lightning, thermodynamic and AVHRR satellite observations are examined to shed light on the roles of updraft and aerosol in providing departures from the green ocean regime toward continental behavior. Extreme case studies are identified in which the updraft control is dominant and in which the aerosol control is dominant. The tentative conclusion gives importance to both updrafts and aerosol in shaping the electrification of tropical convection.

  3. Cloacolith in a blue-fronted amazon parrot (Amazona aestiva).

    PubMed

    Beaufrère, Hugues; Nevarez, Javier; Tully, Thomas N

    2010-06-01

    A 4-year-old blue-fronted Amazon parrot (Amazona aestiva) was admitted for vocalization secondary to constipation. Saline infusion cloacoscopy revealed the presence of a 2-cm-diameter cloacolith within the coprodeum that was obstructing the rectal opening. The cloacolith was fragmented with a pair of biopsy forceps and the pieces removed. The cloacolith was subsequently analyzed and was composed of 100% uric acid salts. The bird improved completely and was able to defecate normally after the procedure. Cloacoliths are relative uncommon cloacal conditions, and this case documents cloacoscopic findings, rectal obstruction, and confirmation of its uric acid composition by urolith analysis. PMID:20806660

  4. Turbulent Rivers Bjorn Birnir

    E-print Network

    Birnir, Björn

    Turbulent Rivers Bj¨orn Birnir Center for Complex and Nonlinear Science and Department the turbulent flow in rivers is proven. The existence of an associated invariant measure describing) function gives rise to Hack's law [16]; stating that the length of the main river, in mature river basins

  5. Rainfall-River Forecasting

    E-print Network

    US Army Corps of Engineers

    Rainfall-River Forecasting: Overview of NOAA's Role, Responsibilities, and Services Rainfall-River Services Division NWS Headquarters Steve Buan Service Coordination Hydrologist NWS North Central River Forecast Center Rainfall-River Forecasting Joint Summit II October 19, 2008 St. Paul, Minnesota 1 #12

  6. The Crooked River Project

    NSDL National Science Digital Library

    Fen Lewis

    This site is home to the Crooked River Project. Developed by youth in Ohio, the Crooked River Project consisted of students studying the Cuyahoga River. This page provides information about the Cuyahoga River on the following subjects: watershed, history, water quality, pollution, recreation, organisms, and reason for concern. Links to other years of this project are available as well.

  7. Global determination of rating curves in the Amazon basin from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Paris, Adrien; Paiva, Rodrigo C. D.; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stéphane; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frédérique

    2014-05-01

    The Amazonian basin is the largest hydrological basin all over the world. Over the past few years, it has experienced an unusual succession of extreme droughts and floods, which origin is still a matter of debate. One of the major issues in understanding such events is to get discharge series distributed over the entire basin. Satellite altimetry can be used to improve our knowledge of the hydrological stream flow conditions in the basin, through rating curves. Rating curves are mathematical relationships between stage and discharge at a given place. The common way to determine the parameters of the relationship is to compute the non-linear regression between the discharge and stage series. In this study, the discharge data was obtained by simulation through the entire basin using the MGB-IPH model with TRMM Merge input rainfall data and assimilation of gage data, run from 1998 to 2009. The stage dataset is made of ~900 altimetry series at ENVISAT and Jason-2 virtual stations, sampling the stages over more than a hundred of rivers in the basin. Altimetry series span between 2002 and 2011. In the present work we present the benefits of using stochastic methods instead of probabilistic ones to determine a dataset of rating curve parameters which are hydrologicaly meaningful throughout the entire Amazon basin. The rating curve parameters have been computed using an optimization technique based on Markov Chain Monte Carlo sampler and Bayesian inference scheme. This technique provides an estimate of the best value for the parameters together with their posterior probability distribution, allowing the determination of a credibility interval for calculated discharge. Also the error over discharges estimates from the MGB-IPH model is included in the rating curve determination. These MGB-IPH errors come from either errors in the discharge derived from the gage readings or errors in the satellite rainfall estimates. The present experiment shows that the stochastic approach is more efficient than the determinist one. By using for the parameters prior credible intervals defined by the user, this method provides an estimate of best rating curve estimate without any unlikely parameter. Results were assessed trough the Nash Sutcliffe efficiency coefficient. Ens superior to 0.7 is found for most of the 920 virtual stations . From these results we were able to determinate a fully coherent map of river bed height, mean depth and Manning's roughness coefficient, information that can be reused in hydrological modeling. Bad results found at a few virtual stations are also of interest. For some sub-basins in the Andean piemont, the bad result confirms that the model failed to estimate discharges overthere. Other are found at tributary mouths experiencing backwater effects from the Amazon. Considering mean monthly slope at the virtual station in the rating curve equation, we obtain rated discharges much more consistent with modeled and measured ones, showing that it is now possible to obtain a meaningful rating curve in such critical areas.

  8. Remineralization rates, recycling, and storage of carbon in Amazon shelf sediments

    NASA Astrophysics Data System (ADS)

    Aller, R. C.; Blair, N. E.; Xia, Q.; Rude, P. D.

    1996-04-01

    Diagenetic reactions and redox properties of Amazon shelf sediments are characterized by extensive vertical and lateral regions of Fe and Mn cycling. This is in contrast to many temperate estuarine and shelf deposits where S can dominate early diagenesis, but may be typical of wet-tropical regions draining highly weathered terrain with energetic coastlines. Although the major pathways of C org remineralization in surfical sediments apparently differ from previously studied areas, the absolute magnitude and relative importance of benthic decomposition on the Amazon shelf are comparable to many shallow water regions of equivalent depth range (10-40 m). Net ?C0 2 production over the upper ˜1-2 m of deposits is >50 mmol m -2 d -1 and has a predominantly planktonic isotopic composition (? 13C˜-21to-22%‰), indicating that marine organic matter largely drives diagenesic reactions and that >20% of average water-column primary production is metabolized on the seafloor. The ?CO 2 production rates in the upper 0-5 cm of sediment tend to increase slightly alongshelf away from the turbid river mouth, but are relatively uniform within cross-shelf transects any given season and independent of net sedimentation rate. Near uniformity in surface decomposition rates, despite substantial offshore increases in water-column productivity and net accumulation at the delta front, implies rapid cross-shelf particle exchange by estuarine circulation and tidal currents. Build-up patterns of pore-water ?CO 2 indicate in some cases that the upper ˜20 cm was deposited only a few days prior to core collection. Benthic ?C0 2 production is highest during periods of low or falling river flow, but no dramatic seasonality occurs. O 2 penetrates ˜2-4 mm into sediments and diffusive OZ uptake averages ˜13 mmol m -2 d -1 annually. Anaerobic metabolism accounts for >75% of sedimentary remineralization, but C/S burial ratios are usually >6 (average world shelf |2.8). Seasonal patterns in sedimentary Fe oxidation states indicate that sediments can be partially reoxidized to depths ˜0.6-1 m during erosion/redeposition and that subsequent Fe reduction can account for much of the anaerobic decomposition. Diffusive ?C0 2 fluxes and pore-water inventories imply substantial loss of remineralized C to authigenic sedimentary-carbonate formation or flux imbalances due to nonsteady-state ingrowth of disturbed pore-water profiles. Reoxidation of metabolites and nutrient release to the water column occur during massive physical remobilization of sediments. The total benthic N remineralization flux (recycled) is comparable to external riverine and shelf-upwelling fluxes. During stable seabed periods, however, little or no co-remineralized N (N 4+, N0 3-, NO 2- or P escapes diffusively into overlying water, indicating the potential for loss of up to ˜100% of the benthic remineralized N (by denitrification) and P (during authigenic mineral precipitation and adsorption). Overall, the shelf apparently acts as an efficient, fluidized-bed denitrification processor (˜50% recycled N) but an inefficient burial sink for riverine and upwelled N. In contrast to the atmospheric sink for N, rapidly regenerated P is eventually lost to the open ocean during sediment resuspension and desorption into the overlying water. Approximately 90% of the remineralized ?CO 2 production flux escapes the sediment and ˜10% is permanently buried as authigenic carbonate. Despite reoxidation and carbonate dissolution during reworking, net burial of C is ˜5 x 10 12 g C total per year, of which ˜25-30% is carbonate from remineralized organics (˜70% of this fraction is marine) ˜20% is residual marine C org, and the remaining (˜50% is residual terrestrial C org. "Refractory" terrestrial POC is apparently subject to repetitive co-oxidation and redox cycling, resulting in remineralization of ˜65-70% of input and leaving less than ˜30-35% of the riverine POC flux stored on the shelf.

  9. Old carbon contributes to aquatic emissions of carbon dioxide in the Amazon

    NASA Astrophysics Data System (ADS)

    Vihermaa, L. E.; Waldron, S.; Garnett, M. H.; Newton, J.

    2014-07-01

    Knowing the rate at which carbon is cycled is crucial to understanding the dynamics of carbon transfer pathways. Recent technical developments now support measurement of the 14C age of evaded CO2 from fluvial systems, which provides an important "fingerprint" of the source of C. Here we report the first direct measurements of the 14C age of effluxed CO2 from two small streams and two rivers within the western Amazonian Basin. The rate of degassing and hydrochemical controls on degassing are also considered. We observe that CO2 efflux from all systems except for the seasonal small stream was 14C-depleted relative to the contemporary atmosphere, indicating a contribution from "old" carbon fixed before ~ 1955 AD. Further, "old" CO2 was effluxed from the perennial stream in the rainforest; this was unexpected as here connectivity with the contemporary C cycle is likely greatest. The effluxed gas represents all sources of CO2 in the aquatic system and thus we used end-member analysis to identify the relative inputs of fossil, modern and intermediately aged C. The most likely solutions indicated a contribution from fossil carbon sources of between 3 and 9% which we interpret as being derived from carbonate weathering. This is significant as the currently observed intensification of weather has the potential to increase the future release of old carbon, which can be subsequently degassed to the atmosphere, and so renders older, slower C cycles faster. Thus 14C fingerprinting of evaded CO2 provides understanding which is essential to more accurately model the carbon cycle in the Amazon Basin.

  10. Old carbon contributes to aquatic emissions of carbon dioxide in the Amazon

    NASA Astrophysics Data System (ADS)

    Vihermaa, L. E.; Waldron, S.; Garnett, M. H.; Newton, J.

    2014-01-01

    Knowing the rate that carbon is cycled is crucial to understanding the dynamics of carbon transfer pathways. Recent technical developments now support measurement of the 14C age of evaded CO2 from fluvial systems, which provides an important "fingerprint" of the source of C. Here we report the first direct measurements of the 14C age of effluxed CO2 from two small streams and two rivers within the Western Amazonian Basin. The rate of degassing and hydrochemical controls on degassing are also considered. We observe that CO2 efflux from all systems except the seasonal small stream was 14C-depleted relative to the contemporary atmosphere, indicating a~contribution from "old" carbon fixed before ~1955 AD. Further, "old" CO2 was effluxed from the perennial stream in the rainforest, unexpected as here connectivity with the contemporary C cycle is likely greatest. The effluxed gas represents all sources of CO2 in the aquatic system and thus we used end member analysis to identify the relative inputs of fossil, modern and intermediately-aged C. The most likely solutions indicated a contribution from fossil carbon sources of between 3 and 9% which we interpret as being derived from carbonate weathering. This is significant as the currently observed intensification of weather has the potential to increase the future release of old carbon, which can be subsequently degassed to the atmosphere, and so render older, slower C cycles faster. Thus 14C fingerprinting of evaded CO2 provides understanding essential to more accurately model the carbon cycle in the Amazon Basin.

  11. Emissions Of Forest Fires In The Amazon: Impact On The Tropical Mountain Forest In Ecuador

    NASA Astrophysics Data System (ADS)

    Fabian, P.; Rollenbeck, R.; Thiemens, M. H.; Brothers, L.

    2006-12-01

    Biomass burning is a source of carbon, sulphur, and nitrogen compounds which, along with their photochemically generated reaction products, can be transported over very large distances, even traversing oceans. Four years of regular rain and fog-water measurements in the tropical mountain forest at the eastern slopes of the Ecuadorian Andes, along an altitude profile between 1800 m and 3185 m, have been carried out. The ion composition of rain and fog-water samples shows frequent episodes of significantly enhanced nitrogen and sulphur, resulting in annual deposition rates of about 5 kg N/ha and 10 kg S/ha into this ecosystem, which are comparable to those of polluted central Europe. By relating back trajectories calculated by means of the FLEXTRA model to the distributions of satellite derived forest fire pixels, it can be shown that most episodes of enhanced ion concentration, with pH values as low as 4.0, can be attributed to biomass burning in the Amazon. First analyses of oxygen isotopes 16O, 17O, and 18O of nitrate in fogwater samples show mass independent fractionation values ranging between 15 and 20 per mille, clearly indicating that nitrate in the samples is a product of atmospheric conversion of precursors, while the isotope data of river samples taken downstream of the research area are grouped in the region of microbial nitrate. This strongly supports the aforementioned trajectory results and shows that the tropical mountain forest in Ecuador, with local pollution sources missing,is "fertilized" by long-range transport of substances originating from forest fires in Colombia, Venezuela, Brazil, and Peru, far upwind of the research site.

  12. Modelling basin-wide variations in Amazon forest photosynthesis

    NASA Astrophysics Data System (ADS)

    Mercado, Lina; Lloyd, Jon; Domingues, Tomas; Fyllas, Nikolaos; Patino, Sandra; Dolman, Han; Sitch, Stephen

    2010-05-01

    Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to use parameterized and validated ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. Recent research has found major differences in above-ground net primary productivity (ANPP), above ground biomass and tree dynamics across Amazonia. West Amazonia is more dynamic, with younger trees, higher stem growth rates and lower biomass than central and eastern Amazon (Baker et al. 2004; Malhi et al. 2004; Phillips et al. 2004). A factor of three variation in above-ground net primary productivity has been estimated across Amazonia by Malhi et al. (2004). Different hypotheses have been proposed to explain the observed spatial variability in ANPP (Malhi et al. 2004). First, due to the proximity to the Andes, sites from western Amazonia tend to have richer soils than central and eastern Amazon and therefore soil fertility could possibly be highly related to the high wood productivity found in western sites. Second, if GPP does not vary across the Amazon basin then different patterns of carbon allocation to respiration could also explain the observed ANPP gradient. However since plant growth depends on the interaction between photosynthesis, transport of assimilates, plant respiration, water relations and mineral nutrition, variations in plant gross photosynthesis (GPP) could also explain the observed variations in ANPP. In this study we investigate whether Amazon GPP can explain variations of observed ANPP. We use a sun and shade canopy gas exchange model that has been calibrated and evaluated at five rainforest sites (Mercado et al. 2009) to simulate gross primary productivity of 50 sites across the Amazon basin during the period 1980-2001. Such simulation differs from the ones performed with global vegetation models (Cox et al. 1998; Sitch et al. 2003) where i) single plant functional type parameter values are assigned and assumed invariant with environmental condition but also ii) these models use leaf N as a factor that limit photosynthesis. Instead, since leaf P may also limit photosynthesis of the tropical forest (Reich et al. 2009), we use a more specific description of photosynthetic capacity across the basin based on the model evaluation done in Mercado et al. (2009) in which canopy photosynthetic capacity is related to foliar P but also using the relationships derived between canopy photosynthesis and leaf nutrients (N and P) from measurements in tropical trees (Domingues et al.In review). A study of this kind can inform the global vegetation/climate community as to the need for variability in key model parameters in order to accurately simulate carbon fluxes across the Amazon basin. Baker, T. R., et al. 2004. Increasing biomass in Amazonian forest plots. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 359 (1443):353-365. Phillips, O. L. et al. 2004. Pattern and process in Amazon tree turnover, 1976-2001. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 359 (1443):381-407. Malhi, Y. et al. 2004. The above-ground coarse wood productivity of 104 Neotropical forest plots. Global Change Biology 10 (5):563-591. Mercado, L.M. et al. 2009. Impact of changes in diffuse radiation on the global land carbon sink. Nature 458 (7241), 1014. Cox, P. M. et al. 1998. A canopy conductance and photosynthesis model for use in a GCM land surface scheme. Journal of Hydrology 213 (1-4):79-9 Sitch, S. et al. 2003. Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Global Change Biology 9 (2):161-185. Reich B. R. et al. 2009. Leaf phosphorus influences the photosynhtesis-nitrogen relation: a cross-biome analysis of 314 species. Oecologia, doi 10.1007/s00442-009-1291-3. Domingues, T. et al. In review. Co-limitation of photosynthetic capacity by nitrogen and phosphorus along a precipitation gradient in West Africa

  13. Effects of CO2 Physiological Forcing on Amazon Climate

    NASA Astrophysics Data System (ADS)

    Halladay, K.; Good, P.; Kay, G.; Betts, R.

    2014-12-01

    Earth system models provide us with an opportunity to examine the complex interactions and feedbacks between land surface, vegetation and atmosphere. A more thorough understanding of these interactions is essential in reducing uncertainty surrounding the potential impacts of climate and environmental change on the future state and extent of the Amazon rainforest. This forest is a important resource for the region and globally in terms of ecosystem services, hydrology and biodiversity. We aim to investigate the effect of CO2 physiological forcing on the Amazon rainforest and its feedback on regional climate by using the CMIP5 idealised 1% CO2 simulations with a focus on HadGEM2-ES. In these simulations, the atmospheric CO2 concentration is increased by 1% per year for 140 years, reaching around 1150ppm at the end of the simulation. The use of idealised simulations allows the effect of CO2 to be separated from other forcings and the sensitivities to be quantified. In particular, it enables non-linear feedbacks to be identified. In addition to the fully coupled 1% CO2 simulation, in which all schemes respond to the forcing, we use simulations in which (a) only the biochemistry scheme sees the rising CO2 concentration, and (b) in which rising CO2 is only seen by the radiation scheme. With these simulations we examine the degree to which CO2 effects are additive or non-linear when in combination. We also show regional differences in climate and vegetation response, highlighting areas of increased sensitivity.

  14. Laboratory evaluation of Amazon forest biomass burning emissions

    NASA Astrophysics Data System (ADS)

    Soares Neto, T. G.; Carvalho, J. A.; Cortez, E. V.; Azevedo, R. G.; Oliveira, R. A.; Fidalgo, W. R. R.; Santos, J. C.

    2011-12-01

    Biomass samples representing Amazon forest native species were burned in laboratory experiments. These species were obtained in the deforestation arc, near the town of Alta Floresta, state of Mato Grosso, Brazil. Moisture content values obtained for twigs and pieces of sticks and leaves of the same species ranged from 9 to 11%, in terms of mass of moisture per total mass. Gas concentrations were measured for carbon dioxide, carbon monoxide, nitrogen oxides, and unburned hydrocarbons. Temperatures, instantaneous burn rates, instantaneous combustion efficiencies and instantaneous emission factors for carbon dioxide and carbon monoxide were evaluated. Burning stages (flaming and smoldering) were identified by visual observation and correlation with the combustion efficiency. The average emission factors were 1565 ± 128, 50.3 ± 17.1, 2.74 ± 0.75, and 14.2 ± 5.9 grams per kg of burned dry biomass, for carbon dioxide, carbon monoxide, nitrogen oxides and unburned hydrocarbons, respectively. These results were compared to average emission factors of carbon dioxide, carbon monoxide, nitrogen oxides and methane determined in field experiments performed in the Amazon region. Agreement with results of field experiments was observed, especially for the flaming stage.

  15. Dusty air masses transport between Amazon Basin and Caribbean Islands

    NASA Astrophysics Data System (ADS)

    Euphrasie-Clotilde, Lovely; Molinie, Jack; Prospero, Joseph; Feuillard, Tony; Brute, Francenor; Jeannot, Alexis

    2015-04-01

    Depend on the month, African desert dust affect different parts of the North Atlantic Ocean. From December to April, Saharan dust outbreaks are often reported over the amazon basin and from May to November over the Caribbean islands and the southern regions of USA. This annual oscillation of Saharan dust presence, related to the ITCZ position, is perturbed some time, during March. Indeed, over Guadeloupe, the air quality network observed between 2007 and 2012 several dust events during March. In this paper, using HISPLIT back trajectories, we analyzed air masses trajectories for March dust events observed in Guadeloupe, from 2007 to 2012.We observed that the high pressure positions over the Atlantic Ocean allow the transport of dusty air masses from southern region of West Africa to the Caribbean Sea with a path crossing close to coastal region of French Guyana. Complementary investigations including the relationship between PM10 concentrations recorded in two sites Pointe-a-Pitre in the Caribbean, and Cayenne in French Guyana, have been done. Moreover we focus on the mean delay observed between the times arrival. All the results show a link between pathway of dusty air masses present over amazon basin and over the Caribbean region during several event of March. The next step will be the comparison of mineral dust composition for this particular month.

  16. The chemical control of soluble phosphorus in the Amazon estuary

    NASA Technical Reports Server (NTRS)

    Fox, L. E.; Wofsy, S. C.; Sager, S. L.

    1986-01-01

    The role of sediments in controlling concentrations of soluble phosphorous in the Amazon estuary is examined. The efflux of phosphorous through the estuary is calculated using data collected on field excursions in December 1982 and May 1983, and laboratory mixing experiments. It is observed that soluble phosphorus was released from bottom sediments at a rate of 0.2 micro-M/day, when in seawater and deionizd water mixtures. The relation between release rates and salinity and sediment concentrations is studied. A one-dimensional dispersion model was developed to estimate phosphate inputs to the estuary. The model predicted total fluxes of soluble inorganic phosphorous of 15 x 10 to the 6th mole/day for December 1982 and 27 x 10 to the 6th mole/day for May 1983; the predictions correlate with field observations. It is noted that phosphorous removal is between 0 and 4 ppt at a rate of 0.044 + or - 0.01 micron-M/ppt per day and the annual mean input of phophorous from Amazon to outer-estuary is 23 x 10 to the 6th moles/day.

  17. Climatic shift in patterns of shallow clouds over the Amazon

    NASA Astrophysics Data System (ADS)

    Chagnon, F. J. F.; Bras, R. L.; Wang, J.

    2004-12-01

    The Amazon rain forest has experienced dramatic changes in the past 50 years due to active deforestation. As of 2001, 15% of the 4,000,000 km2 Brazilian Amazon has been deforested [Instituto Nacional de Pesquisas Espaciais (INPE), 2003]; each year, agricultural exploitation claims an estimated 13,000 km2 of tropical forest [Achard et al., 2002]. In this paper we investigate the climatic effects caused by the observed change of the physical characteristics of the land surface (i.e., increased surface albedo, decreased root-zone depth, decreased surface roughness and decreased leaf-area index). More precisely, we examine the spatial correspondence of shallow cumulus clouds with deforestation. Through the creation of an 8-year record of thrice daily shallow cumulus cloud cover at 1 km resolution from multi-spectral satellite imagery, we quantitatively show the existence of a significant climatic shift in shallow cloudiness patterns associated with deforestation. This shift manifests itself as an enhancement of shallow cumuli over deforested patches, and has potentially important climatic, hydrologic and ecological implications.

  18. Daytime turbulent exchange between the Amazon forest and the atmosphere

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, David R.; Moore, Kathleen E.; Cabral, Osvaldo M. R.; Scolar, Jose; Manzi, Antonio O.; Deabreusa, Leonardo D.

    1989-01-01

    Detailed observations of turbulence just above and below the crown of the Amazon rain forest during the wet season are presented. The forest canopy is shown to remove high frequency turbulent fluctuations while passing lower frequencies. Filter characteristics of turbulent transfer into the Amazon rain forest canopy are quantified. Simple empirical relations that relate observed turbulent heat fluxes to horizontal wind variance are presented. Changes in the amount of turbulent coupling between the forest and the boundary layer associated with deep convective clouds are presented both as statistical averages and as a series of case studies. These convective processes during the rainy season are shown to alter the diurnal course of turbulent fluxes. In wake of giant coastal systems, no significant heat or moisture fluxes occur for up to a day after the event. Radar data is used to demonstrate that even small raining clouds are capable of evacuating the canopy of substances normally trapped by persistent static stability near the forest floor. Recovery from these events can take more than an hour, even during mid-day. In spite of the ubiquitous presence of clouds and frequent rain during this season, the average horizontal wind speed spectrum is well described by dry CBL similarity hypotheses originally found to apply in flat terrain.

  19. Sensitivity of Regional Climate to Deforestation in the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1994-01-01

    The deforestation results in several adverse effect on the natural environment. The focus of this paper is on the effects of deforestation on land-surface processes and regional climate of the Amazon basin. In general, the effect of deforestation on climate are likely to depend on the scale of the defrosted area. In this study, we are interested in the effects due to deforestation of areas with a scale of about 250 km. Hence, a meso-scale climate model is used in performing numerical experiments on the sensitivity of regional climate to deforestation of areas with that size. It is found that deforestation results in less net surface radiation, less evaporation, less rainfall, and warmer surface temperature. The magnitude of the of the change in temperature is of the order 0.5 C, the magnitudes of the changes in the other variables are of the order of IO%. In order to verify some of he results of the numerical experiments, the model simulations of net surface radiation are compared to recent observations of net radiation over cleared and undisturbed forest in the Amazon. The results of the model and the observations agree in the following conclusion: the difference in net surface radiation between cleared and undisturbed forest is, almost, equally partioned between net solar radiation and net long-wave radiation. This finding contributes to our understanding of the basic physics in the deforestation problem.

  20. Vegetation dynamics and rainfall sensitivity of the Amazon

    PubMed Central

    Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Hall, Forrest G.; Myneni, Ranga B.; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J.

    2014-01-01

    We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Niño southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million km2) and across 80% of the subtropical grasslands (3.3 million km2). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Niño events, NDVI was reduced about 16.6% across an area of up to 1.6 million km2 compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics. PMID:25349419