Equine infectious anemia on Marajo Island at the mouth of the Amazon river

Abstract: Equine infectious anemia (EIA) is a transmissible and incurable disease caused by a lentivirus, the equine infectious anemia virus (EIAV). There are no reports in the literature of this infection in Equidae on Marajo Island. The objective of this study was to diagnose the disease in the municipalities of Cachoeira do Arari, Salvaterra, Santa Cruz do Arari and Soure, on Marajó Island, state of Pará, Brazil. For serological survey samples were collected from 294 horses, over 5-month-old, males and females of puruca and marajoara breeds and from some half-breeds, which were tested by immunodiffusion in Agar gel (AGID). A prevalence of 46.26% (136/294) positive cases was found. EIA is considered endemic in the municipalities studied, due to the ecology of the region with a high numbered population of bloodsucking insect vectors and the absence of official measures for the control of the disease.

Effects of anthropogenic and natural hydrological changes on the behavior of the acidic metal discharge from acid sulfate soils in a river- and lake system in western Finland

Larsmo-Öjasjön i Österbotten skapades genom invallningar på 1960-talet pga. industrins behov av sötvatten. Sedan dess har vattenområdet drabbats av återkommande försurning och fiskdöd, och invallningen har ofta beskyllts för problemen. Avhandlingen undersöker syrabelastningen i området; bl.a. hur markanvändning, hydrologi och klimatförändringen påverkar belastningen. Konsekvenserna undersöks med fiskyngel som bioindikator, och olika miljömetoder testas och diskuteras. Ökad kunskap om försurningen hjälper oss att tillämpa effektiva miljömetoder och få förbättrad vattenkvalitet i framtiden. Den primära orsaken till den försämrade vattenkvaliteten under de senaste 40 åren är intensiv dikning av svavelrika sediment. Detta leder till oxidering av svavlet till svavelsyra och uppkomst av sura sulfatjordar. Syran löser upp mängder med toxiska metaller som spolas ut i vattendragen. Undersökningen visar att tiotusentals ton svavelsyra tillsammans med stora mängder metaller rinner till Larsmo-Öjasjön per år från sura sulfatjordar. Åarna bidrar med mest belastning, men den sammanlagda belastningen från de otaliga dikena och bäckarna är oväntat stor. Andra potentiella källor till försurningen, t.ex. muddringar och humussyror, beräknas vara obetydliga. Syra- och metallbelastningen varierar kraftigt med hydrologin, dvs. störst belastning sker under vår- och höstflöden. En eventuell klimatförändring kan ändra på avrinningsmönstret och orsaka mera belastning vintertid. Den årligt återkommande syra- och metallbelastningen kan ofta hindra lakens förökning, vilket kan ha större långtgående konsekvenser för fiskpopulationerna än de relativt sällsynta stora surchockerna med synlig fiskdöd. För att förebygga skador på vattendragen bör man undvika att dränera svavelrika sedimenten. På redan existerande sura sulfatjordar visade sig kontroll av grundvattennivån kunna möjliggöra en effektiverad markanvändning utan märkbart ökade miljökonsekvenser.

Plantas daninhas em mandiocais (Manihot esculenta Crantz) na região mineradora de Diamantina (Alto Jequitinhonha), Minas Gerais

Realizou-se um levantamento das plantas daninhas de mandiocais na região Mineradora de Diamantina (Alto do Jequitinhonha) em Minas Gerais, avaliando-se a composição florística e a estrutura da flora daninha. Percorreram-se os municípios mais representativos desta microregião - Carbonita, Itamarandiba e Capelinha - amostrando as lavou ras indicadas pelos técnicos da EMATER - Empresa de Assistência Técnica e Extensão Rural, coletando e anotando o grau de abundância e a frequência das espécies invasoras, as quais, posteriormente, foram identificadas e na sua maioria depositadas no Herbarium ESAL, da Escola Superior de Agricultura de Lavras, MG. Constatou-se a presença de 45 espécies pertencentes a 19 famílias, sendo 16 dicotiledôneas, 2 monocotiledôneas e 1 pteridóphyta. Destacaram-se as famílias Compositae, Gramineae, Malvaceae, Leguminosae, Rubiaceae e Convolvulaceae e as espécies Acanthospermum australe, Sida rhombifolia e Borreria alata.

Similarity among periphyton algal communities in a lentic-lotic gradient of the upper Paraná river floodplain, Brazil

Floristic comparison of periphyton communities from three systems with different hydrodynamic regimes (lentic, semilotic, and lotic) was carried out during high and low water periods on the Upper Paraná River floodplain. For each period and system, glass slides were sampled every two days during 18-day periods, and Eichhornia azurea Kunth petioles were sampled three times. A total of 228 species was collected, representing 12 classes, mainly diatoms and desmids. The highest species-richness was found in communities from lentic system and during high water. Species richness in the lotic system was more stable over succession and hydrological periods. Algal taxonomic structure in river community was clearly separated from the other two systems, with 43% of similarity level. The hydrological period was next in importance, followed last by the substratum type, with communities associated at 65-78% similarity levels, depending on system and hydrological period. The type of system, but not the water levels,was the main factor that influenced community richness, followed by disturbances caused by flood pulses and the operation of reservoirs upstream. The periphyton on artificial and natural substrata presented high degree of similarity.

Phytosociology of the remaining xerophytic woodland associated to an environmental gradient at the banks of the São Francisco river - Petrolina, Pernambuco, Brazil

Floristic and phytosociological surveys were carried out for 12 months in the Embrapa-SPSB, Petrolina, Pernambuco, Brazil. A transect was laid on starting at the river bank extending for 790 m away from the river and divided into 140 10 × 10 m contiguous plots. In each plot, all standing plants, alive or dead, with stem diameter at soil level > 3 cm and total height > 1 m were sampled. Along this transect, an elevation range of 9.40 m was registered and five topographical environments were identified: riverside (MR), dike (D), floodable depression (DI), boundary terrace (TL) - all of them belonging to the fluvial terrace with Fluvic Neosol and Haplic Cambisol both silty textured eutrophic soils - and the inlander tableland (TS), with medium sandy-textured Red-Yellow Argisols. Fourty-eight species/morphospecies, distributed into 39 genera and 21 families, were identified. Four phytogeoenvironments (MR, D + TL, DI + TL, and TS) were registered based on environmental variations and floristic similarities among plots using cluster analyses. The MR environment showed the largest total density, total basal area, maximum and medium heights and maximum diameter. Moreover, it had 8.1% of plants with heights above 8 m against 0.6% for D + TL, 0.2% for DI + TL, and 0% for TS. The species with the largest importance value were Inga vera subsp. affinis (DC.) T.D. Pennington in MR, Mimosa bimucronata Kunth in D + TL and DI + TL and M. tenuiflora (Willd.) Poir. in TS.

Alismatales from the upper and middle Araguaia river basin (Brazil)

The present study deals with a survey of the order Alismatales (except Araceae) in the upper and middle Araguaia River region located between the states of Mato Grosso and Goiás, Brazil. Field expeditions were carried out during the rainy and dry seasons. The route covered approximately 2,000 km and 41 aquatic environments were visited. Thirteen taxa, representing the families Alismataceae (nine), Hydrocharitaceae (three) and Najadaceae (one) were identified. Keys for the identification of families and species in field, brief diagnoses, schematic illustrations and relevant comments were elaborated based on field observations as well as on the analysis of the specimens collected.

Impacts of the Belo Monte hydroelectric dam construction on pioneer vegetation formations along the Xingu River, Pará State, Brazil

There is an important pioneer vegetation formation along the Xingu River in the area where the Belo Monte hydroelectric dam is being constructed that is highly adapted to a seasonally fluctuating water levels. The aim of this study was to examine the habitat and flora of the pioneer formations in the Belo Monte area. The area was divided in three sections for study purposes (Reservoir, Low Flow, and Control) that were expected to experience different degrees of impact from the dam project. The calculations of habitat losses were based on satellite imagery classifications, and a total of 111 plots were established in the three areas for vegetation sampling. Habitat losses of the pioneer formations will total 89.7% when the project is fully functional. Forty-five of the 72 recorded species are restricted to single areas. Species richness and diversity were significantly lower in the control area. The completion of the Belo Monte reservoir will result in habitat reductions and will consequently reduce the richness and diversity of pioneer formations. Studies suggest monitoring the populations located in the reduced flow area to determine possible impacts resulting from changes in the regional hydrological cycle caused by the Xingu River dam.

Genetic variability of Prochilodus lineatus (Characiformes, Prochilodontidae) in the upper Paraná river

The genetic variability of the "curimba", Prochilodus lineatus, from three locations in the Paraná river basin, was investigated by starch gel electrophoresis. A total of 160 specimens were analyzed for 19 enzymes, 12 of which permitted successful interpretation of electrophoretic patterns. Eighteen loci were identified and six of them proved to be polymorphic (EST-1*, EST-2*, IDH-1*, PGM-1*, PGM-2*, LDH-2*). Mean heterozygosity was considered high (13%) by comparison with the literature. A low level of differentiation was found among subpopulations, with mean F ST = 0.018. Values of genetic distance and genetic identity suggest that, at least along this stretch of the river, P. lineatus comprises a single breed with high gene flow. This analysis has important implications for fishery management, aquaculture, and conservation of the stocks

Low pH and calcium effects on net Na+ and K+ fluxes in two catfish species from the Amazon River (Corydoras: Callichthyidae)

The present study analyzes Na+ and K+ disturbances caused by low pH in two catfish species from the Amazon River. Corydoras adolfoi inhabits ion-poor, black-stained, low pH (3.5-4.0) waters, while C. schwartzi is native to ion-rich waters at circumneutral pH. Fish were exposed to pH 3.5 Ca2+-free, and Ca2+-enriched (~500 µmol/l) water to determine the protective effects of calcium. Net Na+ and K+ fluxes were measured in the water collected from the fish experimental chambers. C. adolfoi was unable to control the Na+ efflux at low pH, exhibiting Na+ loss up to -594 ± 84 nmol g-1 h-1 during the first hour. After 3 and 6 h, net Na+ flux increased by 7- and 23-fold, respectively. In C. schwartzi, at pH 3.5, the initial high Na+ loss (-1,063 ± 73 nmol g-1 h-1) was gradually attenuated. A K+ loss occurred in both species, but remained relatively constant throughout exposure. High [Ca2+] affected ion losses in both species. C. adolfoi had 70% loss attenuation, indicating incapacity to control Na+ efflux. In C. schwartzi, elevated [Ca2+] completely prevented the Na+ losses caused by exposure to low pH. Rather different patterns were seen for K+ fluxes, with C. adolfoi showing no K+ disruption when exposed to low pH/high [Ca2+]. Thus, C. adolfoi loses Na+ during acid exposure, but has the ability to control K+ loss, while C. schwartzi controls diffusive Na+ loss but exhibits a slightly higher K+ loss. Ion balance was influenced by [Ca2+] at low pH in C. schwartzi but not in C. adolfoi.

Map of the sources of Snake River : with its tributaries together with portions of the headwaters of the Madison and Yellowstone from surveys and observations of the Snake River Expedition

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

Map of the sources of Snake River : with its tributaries together with portions of the headwaters of the Madison and Yellowstone from surveys and observations of the Snake River Expedition

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

Map of the Lower Geyser Basin of the Upper Madison River

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

Map of the Upper Geyser Basin on the Upper Madison River, Montana Terr.

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan