Preliminary study on the diffusion dynamics characteristics of Biomphalaria straminea in Southern China / 公共卫生与预防医学

Objective To study the dynamic diffusion characteristics of Biomphalaria straminea in Shenzhen, Dongguan and Huizhou of Southern China. Methods B. straminea was monitored at 25 investigation points along 10 river channels in Shenzhen, Dongguan and Huizhou by salvaging method. The diffusion characteristics of snails along with water in the Guihua New Village section of the Guanlan River and the Dawei Village section of the Longgang River were analyzed by GPS location drift test. In addition, the influence of flooding on the diffusion of B. straminea in the Kuichong River both before and after Typhoon "Shanzhu" was analyzed by monitoring the hydrology and distribution of snails. Results In March and October from 2016 to 2018, a total of 1 176 kg of floating objects were salvaged in rivers in Shenzhen, Dongguan and Huizhou. Scattered B. straminea were found on water hyacinths. Drift test of floats with GPS showed that the average drift speed of GPS floating objects was close to the river surface velocity. Affected by river current and wind direction, the GPS floats quickly drifted to the river bank and stopped in the stagnant area due to the blockade of water plants, stone and the bending of the shoreline. The drift distance of each time was between 136 - 715m. The test results of salvaged floating objects found that the loss rates of B. straminea were 46.70% - 60.00% and 22.10% - 30.80%, in the Guihua New Village section of the Guanlan River and the Dawei Village section of the Longgang River, respectively, which were significantly affected by the floating weight, river velocity and drifting distance. The analysis of the hydrology and distribution of B. straminea in the Kuichong River both before and after Typhoon "Shanzhu" showed that the density of B. straminea in the river was significantly reduced by the flood. Conclusion B. straminea is mainly transported as suspended matter in water body, and flooding was an important factor in its long-distance diffusion.

Influence of inlet water on the biotic and abiotic variables in a fish pond / Influência da água de entrada sobre as variáveis bióticas e abióticas em um viveiro de piscicultura

Abstract The effects of treated and untreated water inlets with macrophytes on the improvement of water quality and zooplankton community were evaluated in a fish pond with continuous water flow. Water and zooplankton samples were retrieved at four sites during nine months. There were differences (p<0.01) between inlet water from fish pond and inlet water from canal with macrophytes, featuring higher concentrations of nutrient load, mainly TAN and TP in the former. The inlet water from fish pond contained a higher number of abundant species (9 species), whilst the water supply from the canal with macrophytes had a greater richness (31 species) of zooplankton species. Results showed that inlet water without macrophytes directly affected the characteristics of the water column and the dominance of zooplankton species such as Thermocyclops decipiens, and greater abundance of Rotifera species. Since aquatic plants in the inlet water of fish pond analyzed showed lower allochthonous material loads from the previous fish pond, the management adopted with macrophytes may be applied to avoid eutrophication risks, common in farm ponds.

Resumo Os efeitos do abastecimento tratado e não tratado com macrófitas sobre a qualidade da água e comunidade zooplanctônica foram avaliados em um viveiro de piscicultura com fluxo contínuo de água. Houve maior concentração de fósforo total e nitrogênio amoniacal na água não tratada (p<0,01). Na água de entrada sem tratamento de macrófitas foi observado maior número de espécies abundantes (9 espécies), contudo, a entrada de água tratada com macrófitas apresentou maior riqueza de espécies (31 espécies) zooplanctônicas. Os resultados obtidos mostraram que a água de entrada sem macrófitas influenciou as características da coluna de água com predominância de espécies zooplanctônicas, como Thermocyclops decipiens e maior abundância de espécies de Rotifera. A água tratada com macrófita apresentou menor carga de materiais alóctones provenientes do viveiro anterior, indicando que o manejo adotado com macrófitas pode ser aplicado para evitar riscos de eutrofização, comuns em piscicultura.

Integrated Water Resources Models to Support Analysis of Integrated Regional Water Management Programs in California.

Aims: Provide a review of key features and several applications of the family of Integrated Water Resources (IWR) models, as the key analytical tools used in evaluation of hydrologic conditions in support of the integrated regional water management (IRWM) programs in California. Methodology: IWR models are a family of models consisting of the Integrated Groundwater and Surface water Model (IGSM), the Integrated Water Flow Model (IWFM), and the IWFM Demand Calculator (IDC). IGSM is an integrated model that simulates the complete hydrologic cycle for a basin. The California Department of Water Resources (CADWR) has upgraded and enhanced the IGSM code and developed an enhanced version, called IWFM. In addition, CADWR extracted the land surface processes module of IWFM as an independent unit, called IDC, which can be used as a stand-alone model for estimating agricultural water demand, groundwater pumping, and deep percolation. The IWR models have been applied to many basins throughout California to evaluate hydrologic conditions, including evaluation of land and water use, surface water and groundwater flow, stream-aquifer interaction, reservoir operation, land subsidence, and regional water quality conditions. An ArcGIS-based Graphical User Interface provides a robust modeling platform for the IWR models. Results: The IWR models have had significant success in analysis of various types of water resources projects, such as integrated regional water management programs, groundwater management and conjunctive use operations, groundwater recharge investigations, water transfer programs, water quality, water demand and supply analysis, seawater intrusion, and climate change vulnerability and adaptation analysis. Conclusion: The IWR models are effective tools in analyzing the technical issues involved in integrated water management and planning in California. These IWR models are well suited for analysis of hydrologic conditions and alternative water management scenarios explored in various basin management and IRWM programs.

Spawning of migratory fish species between two reservoirs of the upper Uruguay River, Brazil

This study investigated the migratory fish spawning within the reservoirs of the Machadinho and Itá dams (upper Uruguay River, Brazil) and its relationship to environmental variables. Sampling was conducted in the lotic region of the river in two sites between the dams' reservoirs: Uruguay (main river) and Ligeiro (tributary). Sampling included nine consecutive reproductive periods (RP) spanning the period from 2001 to 2010 and was conducted at night on the water surface using cylindrical-conical plankton nets (0.5 mm mesh); environmental variables were also recorded. The spawning of the migratory species Salminus brasiliensis, Prochilodus lineatus, and Steindachneridion scriptum was registered: S. brasiliensis and P. lineatus spawned in the tributary river at the end of spring/beginning of summer, during flooding and during periods of high water temperature. Steindachneridion scriptum spawned in the main river at the beginning of spring. The study showed that S. brasiliensis, P. lineatus, and S. scriptum are able to spawn in small lotic river stretches within two reservoirs, but only under very specific and not common environmental conditions.

Este estudo verificou a presença de desova de peixes migradores entre os reservatórios das Usinas Hidrelétricas de Machadinho e Itá (alto rio Uruguai, Brasil), e sua relação com as variáveis ambientais. As amostragens foram realizadas na região lótica do rio Uruguai, no trecho situado entre os reservatórios de Itá e Machadinho, em duas estações de amostragem: Uruguai (Principal) e Ligeiro (Tributário). As coletas abrangeram nove períodos reprodutivos (PR) consecutivos, desde 2001 até 2010, e foram realizadas no período noturno, na superfície, com o uso de redes de plâncton do tipo cilíndrico-cônicas de malha 0,5 mm, quando também foram registradas as variáveis ambientais. O estudo registrou a desova de três espécies migradoras: Salminus brasiliensis, Prochilodus lineatus e Steindachneridion scriptum. As populações de S. brasiliensis e P. lineatus desovaram no rio tributário no final da primavera e início do verão em condições de enchentes e temperatura da água mais alta. Steindachneridion scriptum desovou no rio principal durante o início da primavera. O presente estudo mostra que S. brasiliensis, P. lineatus e S. scriptum conseguem desovar em pequenos trechos lóticos de rio entre dois reservatórios, porém em condições ambientais determinadas e pouco frequentes.

Effect of water flow rate and feed training on "pacamã" (Siluriforme: Pseudopimelodidae) juvenile production / Efeito do fluxo de água e do condicionamento alimentar na produção de juvenis de pacamã (Siluriforme: Pseudopimelodidae)

The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400) were stocked at a density of 5 larvae/L. Different water flow (F) rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm) were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion). The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.

Avaliaram-se os efeitos de diferentes fluxos de água e do condicionamento alimentar sobre a produção de juvenis de pacamã Lophiosilurus alexandri. Larvas com nove dias pós-eclosão (n=2.400) foram estocadas na densidade de 5 larvas/L. Diferentes fluxos (F) de água foram testados: F1 = 180; F2 = 600; F3 = 1.300; e F4 = 2.600mL/min. Náuplios de Artemia foram usados como alimento nos primeiros 15 dias de alimentação ativa. No segundo experimento, para o condicionamento alimentar, 720 juvenis (comprimento total de 22,2mm) foram estocados na densidade de 1,5 juvenis/L. Fluxo de água similar a F1 foi utilizado. Foram testados o uso de dieta extrusada e o condicionamento alimentar adicionado ou não de náuplios de Artemia ou emulsão Scott. Os diferentes fluxos de água não afetaram a sobrevivência e o crescimento de L. alexandri. Durante o condicionamento alimentar foi registrada a ocorrência de canibalismo. Pior sobrevivência, taxa de crescimento específica e maior mortalidade foram registradas para o uso da dieta comercial, enquanto valores similares foram verificados para as diferentes dietas usadas no condicionamento alimentar. Fluxo de água reduzido pode ser empregado durante a larvicultura e condicionamento alimentar de L. alexandri.

Water quality in six sequentially disposed fishponds with continuous water flow / Qualidade da água em seis viveiros de piscicultura com fluxo contínuo de água em disposição seqüencial

This study evaluated selected limnological variables in inlet water in six sequentially distributed semi-intensive fishponds. Data were collected during 15 consecutive days in three distinct grow-out periods (May, October and January). Only phosphorus and pH varied among sites and periods (p 0.05) occurred in the cases of nitrite and dissolved oxygen. No variation was reported with regard to dissolved oxygen, conductivity, alkalinity, free CO2, bicarbonate, chlorophyll-a, nitrite and ammonia did not vary throughout the period (p > 0.05). In May, or rather, the final grow-out period, the fishponds displayed high concentrations, mainly in nitrogen compounds. As from fishpond 3, the inlet water contained high levels of nutrients. The water is passed from pond to pond, evidencing the need for management practices adequate to the specific conditions of each pond. Water quality should be monitored more frequently during high grow-out period when food addition is more intense. Thereafter, more care should be taken, as highest phosphorus concentrations occurred in May.

Este estudo verificou algumas variáveis limnológicas na água de entrada em seis viveiros de criação semi-intensiva de peixes com distribuição sequencial de água em três períodos distintos de engorda de peixes (maio, outubro e janeiro), durante 15 dias consecutivos em cada período. Somente o fósforo e pH variaram entre os pontos e períodos de coleta (p 0,05) ocorreu com nitrito e oxigênio dissolvido. Ao longo do período não foram significativas (p > 0,05) as variáveis como oxigênio dissolvido, condutividade, alcalinidade, CO2 livre, bicarbonato, clorofila-a, nitrito e amônia. No mês de maio, correspondente ao final do período de engorda de peixes, os viveiros apresentaram em geral maiores concentrações, principalmente, em relação aos compostos nitrogenados. A partir do viveiro 3 a água de entrada apresentou teores mais elevados de nutrientes em função da passagem direta de água de um viveiro para o outro, evidenciando a necessidade de práticas de manejo voltadas para as condições específicas de cada viveiro. A qualidade da água dos viveiros deve ser monitorada mais frequentemente, durante o período de engorda dos peixes, porém, após este período cuidados devem ser tomados visto que em maio foram observadas as maiores concentrações de fósforo na água.

Velocidade da água e a distribuição de larvas e pupas de Chirostilbia pertinax (Kollar) (Diptera, Simuliidae) e macroinvertebrados associados / Water velocity and the distribution of larvae and pupae of Chirostilbia pertinax (Kollar) (Diptera, Simuliidae) and associated macroinvertebrates

The objective of the current study was to evaluate the distribution of the immature stages of Chirostilbia pertinax (Kollar, 1832) and associated bentic macroinvertebrates in relation to water velocity. This study was carried out on the upper course of Sinos river, in Rio Grande do Sul. Seasonal collections of larvae and pupae of black flies and associated benthic fauna were carried out at five places. In all sampling sites artificial substrates were installed, remaining submersed for 14 days in places of great water flow. Before removing the substrates the flow speeds on the collection sites were measured. To assess the distinct distribution patterns of the benthic fauna, the flow speed was divided in three classes: slow (0.20 - 0.63 m/s), medium (0.64 - 1.07 m/s) and fast (1.08 - 1.50 m/s). A total of 39,598 specimens were collected, from which 33,418 were black flies and 6,180 associated macroinvertebrates. From the total black flies, 5,704 were in the last larval instar and pupae from which 828 were C. pertinax. In the distribution of this species 30.8 percent occurred in slow flow, 24.9 percent in medium flow and 44.3 percent in fast flow. The abundance of C. pertinax is inversely related to the predatory macroinvertebrates (GLM, R² = 0.207; F 2.50 = 6.536; P = 0.003). These results demonstrate that the immature stages of C. pertinax have a tendency to occupy microhabitats with less predator occurrence.

O presente trabalho objetivou investigar a relação entre a velocidade da água e a distribuição dos estágios imaturos de Chirostilbia pertinax (Kollar, 1832) e os macroinvertebrados bentônicos associados. As coletas foram realizadas em cinco pontos, no trecho superior do Rio dos Sinos, no Estado do Rio Grande do Sul. A fauna bentônica foi amostrada com substratos artificiais, que permaneceram instalados nos locais de maior corenteza d'água por períodos de 14 dias. Antes do recolhimento dos substratos foram realizadas medidas de velocidade d'água no local da sua instalação. Essas medidas foram agrupadas em três classes: baixa (0,20 a 0,63 m/s), média (0,64 a 1,07 m/s) e alta (1,08 a 1,50 m/s) para posterior relação com a distribuição da fauna coletada. Para avaliar a influência da velocidade de água sobre a distribuição dos macroinvertebrados e a abundância de C. pertinax foi realizada uma regressão múltipla. As coletas resultaram em 39.598 indivíduos, sendo 33.418 simulídeos e 6.180 macroinvertebrados associados. Entre os simulídeos 5.704 espécimes correspondem a larvas do último ínstar e pupas, dos quais 828 são de C. pertinax. Quanto à distribuição dessa espécie, 30,8 por cento ocorreram na classe de baixa velocidade d'água, 24,9 por cento na velocidade média e 44,3 por cento na alta velocidade. Foi observado que a abundância de C. petinax aumenta à medida que os macroinvertebrados predadores diminuem e os organismos não predadores aumentam (GLM, R² = 0,207; F 2,50 = 6,536; P = 0,003). Esses resultados revelam que os imaturos de C. pertinax têm uma tendência em ocupar um microhábitat com menor ocorrência de predadores.

Estrutura da comunidade de macroinvertebrados associados ao folhiço submerso de remanso e correnteza em igarapés da Amazônia Central / Community structure of macroinvertebrates associated with leaf litter from riffles and pools from Central Amazon streams

Considerando que a composição e a distribuição de macroinvertebrados de água doce é relacionada a diversos fatores ambientais, destacando-se a velocidade da corrente e o tipo de substrato tive como hipótese de trabalho que a composição, riqueza, e abundância de macroinvertebrados que ocorrem em dois ambientes com características hidrológicas distintas (correnteza e remanso) fossem diferentes entre essas áreas. A amostragem foi realizada em três igarapés onde foram dispostas cinco armadilhas em trechos de remanso e cinco em correnteza, totalizando 30 armadilhas. No laboratório os macroinvertebrados foram identificados em ordens e os indivíduos de cada ordem foram separados em famílias. Análise de variância em blocos foi realizada com intuito de verificar possíveis efeitos do tipo de hábitat e dos rios sobre riqueza e abundância de macroinvertebrados. O índice de diversidade Shannon foi aplicado, seguido do teste t. Análise de agrupamento (UPGMA) usando o coeficiente de distância de Bray-Curtis foi realizada com intuito de verificar a similaridade entre os diferentes hábitats dos rios. Foram coletados 132 especimens, 97 em correnteza e 35 em remanso. Dentre as dezesseis famílias coletadas, seis colonizaram apenas correnteza, dois apenas remanso e oito colonizaram os dois ambientes. Foi detectado um efeito do hábitat (remanso ou correnteza) sobre a riqueza e abundância de macroinvertebrados. No entanto, não foi detectado efeito do local (igarapés). A diversidade de Shannon foi maior para correnteza do que para o remanso. A análise de agrupamento de Bray-Curtis formou um agrupamento mais definido entre os trechos de corredeira. Concluo que a composição e a abundância são os parâmetros que diferem entre as comunidades de macroinvertebrados de correnteza e remanso. A hipótese explicativa para este resultado é de que a estrutura da comunidade desses dois ambientes se diferencie devido às variações associadas ao fluxo da correnteza, que possibilitam...

Considering that the composition and distribution of freshwater macroinvertebrates is related to several environmental factors, especially water flow and type of substratum I hypothesized that composition, richness and abundance of macroinvertebrates that occur in both environments with distinct hydrological characteristics (riffle and pool) were different between these areas. Specimens were sampled in three streams where five traps were arranged in stretches from pools and riffles totalizing 30 traps. In the laboratory the macroinvertebrates were identified to family level. An analysis of variance in blocks was made in order to verify possible effects of habitat and stream type on the richness and abundance of macroinvertebrates. Shannon's diversity index was applied, followed by a t-test. The Bray-Curtis cluster analysis was performed to verify the similarity between different habitats. A total of 132 specimens were collected, 97 in riffles and 35 in pools. Among sixteen families collected, six colonized only riffles, two colonized only pools and eight colonized both environments. An effect of the habitat (pools or riffles) upon the richness and abundance of macroinvertebrates was detected. On the contrary, no difference was found among streams (igarapés). The Shannon diversity index was higher in riffles than in pools. The riffle stretches formed a single group on the Bray-Curtis cluster analysis. I conclude that composition and abundance were distinct between the community of macroinvertebrates of riffles and pools. The explaining hypothesis for these results is that the community structure of both environments is distinct due to variations associated with water flow, that allows the existence of groups with different ecological and behavioral features.

EFFECTS OF SWIMMING ON VISION / 体力科学

This study was conducted to examine the effects of different types of swimming on vision, including contrast sensitivity, depth perception, static visual acuity, number of eyeblinks, and pain scale. Six college water-polo players swam (A) at a water flow rate of 0 m·sec<SUP>-1</SUP> with floating, (B) at 0.83±0.04 m·sec<SUP>-1</SUP> with floating, (C) at 1.09±0.05 m·sec<SUP>-1</SUP> with floating, (D) at 0.83±0.04 m·sec<SUP>-1</SUP> doing the front crawl (50%VO<SUB>2</SUB>max), and (E) at 1.09±0.05 m·sec<SUP>-1</SUP> doing the front crawl (80%VO<SUB>2</SUB>max) for 15 min on a swimmill. To avoid the effect by chlorine, the free radical residual chlorine concentration was fixed at 0 ppm in the swimmill.<BR>We found no significant differences in vision before and after A. On the other hand, contrast sensitivity during the test decreased significantly in C and E (p<0.05) . Depth perception and number of eyeblinks increased significantly in C and E (p<0.05) . Subjects had a high pain scale in C and E (p<0.01) . Thus it seems that water flow may disturb of vision. We conclude that it is impor. tant for swimmers to prevent impairment of vision.