Larvae of the North American Caddisfly Genera (Trichoptera).

Yeasts are ubiquitous in their distribution and populations mainly depend on the type and concentration of organic materials. The distribution of species, as well as their numbers and metabolic characteristics were found to be governed by existing environmental conditions. Marine yeasts were first discovered from the Atlantic Ocean and following this discovery, yeasts were isolated from different sources, viz. seawater, marine deposits, seaweeds, fish, marine mammals and sea birds. Near-shore environments are usually inhabited by tens to thousands of cells per litre of water, whereas low organic surface to deep-sea oceanic regions contain 10 or fewer cells/litre. Aerobic forms are found more in clean waters and fermentative forms in polluted waters. Yeasts are more abundant in silty muds than in sandy sediments. The isolation frequency of yeasts fell as the depth of the sampling site is increased. Major genera isolated in this study were Candida, Cryptococcus, Debaryomyces and Rhodotorula. For biomass estimation ergosterol method was used. Classification and identification of yeasts were performed using different criteria, i.e. morphology, sexual reproduction and physiological/biochemical characteristics. Fatty acid profiling or molecular sequencing of the IGS and ITS regions and 28S gene rDNA ensured accurate identification.

https://dyuthi.cusat.ac.in/xmlui/bitstream/handle/purl/2035/Marine%20yeasts-a%20rewiew.pdf;sequence=1

Marine yeasts — a review

O crescimento das cidades nas ultimas decadas tem sido responsavel pelo aumento da pressao das atividades antropicas sobre os recursos naturais. Em todo o planeta, praticamente nao existe um ecossistema que nao tenha sofrido influencia direta e/ou indireta do homem, como por exemplo, contaminacao dos ambientes aquaticos, desmatamentos, contaminacao de lencol freatico e introducao de especies exoticas, resultando na diminuicao da diversidade de habitats e perda da biodiversidade.

/pdf/bioindicadores-de-qualidade-de-agua-como-ferramenta-em-4kdwe843hv.pdf

Bioindicadores de qualidade de água como ferramenta em estudos de impacto ambiental 1

Summary
1. The term ‘catastrophic drift’ is used to describe the large-scale displacement of invertebrates that occurs during periods of increased river discharge. However, the physical processes that lead to animals entering the water column at such times remain poorly understood. Specifically, the hypothesis that the movement of bed sediments during floods triggers a large increase in drift has lacked a rigorous field test.

2. Using a portable flume, the hydraulic conditions and rates of bedload transport associated with small, frequent floods were created in situ within a reach of a gravel bed river. Experiments focussed on the patches of fine sediment which are the dominant source of bed material transported during small floods. The flume produced near bed velocities of up to 2 m s−1 over the patches, increasing shear stress, initiating sediment transport and causing invertebrates to enter the drift.

3. The total number of individuals lost from the bed, as well as the taxonomic composition of the drift, were influenced strongly by shear stress and bedload. The rate of loss from the bed was low at shear stresses <9 dynes cm−2 (0–4 individuals min−1 from the 0.5 m2 flume bed area). Once shear stress exceeded 9 dynes cm−2, the threshold that resulted in consistent bedload transport from the patches, the rate of loss of animals increased to a maximum of 56 individuals min−1. When bedload transport rates were at their highest, the taxonomic composition of the drift was more similar to the benthos than it was to the drift observed when bed material was stable.

4. Absolute rates of bedload transport created by the manipulations were extremely low (<7 g m−1 s−1) and typical of those measured during small, frequent floods. Events of this magnitude do not break up the armour layer across the reach as a whole and so exposed patches of fine sediment are the principal source of bedload material. Consequently, discharge events not considered as disturbances in geomorphic terms may initiate frequent episodes of so-called ‘catastrophic drift’ from patches of stream bed.

When is stream invertebrate drift catastrophic? The role of hydraulics and sediment transport in initiating drift during flood events

In the last few years, awareness in developed countries has increased regarding the importance of urban watercourses as essential natural resources for human well being. Macro- invertebrates have been used as bioindicators to complement physico-chemical evaluation of water quality after environmental perturbations. The city of Manaus is closely associated with the Amazonian rain forest and with its dense hydro- graphic network. Any perturbation, such as deforestation and/or water pollution in the city's streams, therefore causes changes in the local ecosystem as the population increases. In this study, 65 streams were sampled in October and November 2003. Samples were taken from stream- bed sediment in the center of the channel and litter/sediment at the edge of the stream. Defor- estation, total Nitrogen (TN), total Phosphorus (TP), depth, width, electrical conductivity, tem- perature and dissolved Oxygen (DO) were mea- sured. A total of 115,549 specimens were collected, distributed among 152 taxa. Oligocha- eta, Chironomus, Psychodidae and Ceratopogon- idae were the taxa with the greatest frequencies of occurrence and the highest total abundances. Higher deforestation, TN and TP were correlated with lower DO and greater electrical conductivity, pH and water temperature. Deforestation, TN and TP were not associated with water velocity and stream width. Depth was the only variable

Deforestation and sewage effects on aquatic macroinvertebrates in urban streams in Manaus, Amazonas, Brazil

http://d3m21rn3ib0riu.cloudfront.net/PAT/Upload/449865/ARTIGO%20monitoramento%20ambiental%201_20130830151944.pdf

Macroinvertebrados Bentônicos como Ferramenta para Avaliar a Saúde de Riachos

"The objective of this study was to use a protocol of rapid habitat diversity evaluation in teaching and researching activities, assessing the water and sediment characteristics, land use, embankments, riparian vegetative zone width, bank vegetative protection, size and frequency of riffles and pools, and the conservation status. This protocol was elaborated based on the Hannaford et al. (1997) and on the Environmental Protection Agency (1987) (Ohio, EUA), adapted to the conditions of the altitudinal lotic ecossystems [sic] from the Minas Gerais and Rio de Janeiro States. The results were obtained during the Biology undergraduation and the Ecology graduated field courses from ICB/UFMG. The study areas were the Serra do Cipo National Park (MG) and the Bocaina National Park (RJ). No significative differences were found in the results when comparing pre-assessment trained students with no pre-assessments trained students, pointing out the easy utilization of the protocol during the building capacity process in habitat assessment. The use of this protocol constitutes a pratical [sic] tool in research studies on the assessment of habitats diversity in watershed stretches with different conservation levels of their natural conditons, and also on environmental impact evaluation studies"

Aplicação de um protocolo de avaliação rápida da diversidade de habitats em atividade de ensino e pesquisa (MG-RJ)

In order to verify the cascade-system effect in benthic macroinvertebrate communities, and the implications for policy making and proposals for conservation and sustainable use of the lower portion of Sao Francisco river basin (Bahia State, Brazil), a three-reservoir cascade system including two stretches downstream were studied during dry (June, 1997) and rainy (March, 1998) periods. The dominant groups found were Mollusca (Melanoides tuberculata), Oligochaeta, and Chironomidae larvae. Low Shannon-Wiener and Pielou index values were found, but with no significant difference between the sampling periods. However, density and taxonomic richness were significantly different (t(0.05; 31) = -2.1945; p < 0.05; e t(0.05; 31) = -3.0600; p < 0.01) between the sampling periods, with a reduction in the number of taxaand macroinvertebrate abundance during the rainy period. An increasing gradient in benthic macroinvertebrate community structures was noted along the reservoir cascade from the first reservoir (Apolonio Sales), followed by a decrease downstream from the third reservoir of the system (Xingo). Despite the negative consequences of rapid proliferation of dams, which have caused widespread loss of freshwater habitats, the reservoir cascade system promoted an increase in benthic macroinvertebrate diversity, due to water-quality improvement along the system.

Biodiversity assessment of benthic macroinvertebrates along a reservoir cascade in the lower São Francisco river (northeastern Brazil)

The main goals of this study were: 1) to evaluate the structure, diversity, and functional trophic group composition of benthic macroinvertebrate communities; 2) to characterize water quality in the headwaters of the Doce river watershed, based on physical, chemical, and biological parameters (benthic macroinvertebrates, fecal coliforms, heterotrophic bacteria, and yeasts); and 3) to contribute to the knowledge of the structure and function of longitudinal gradients in lotic ecosystems in Brazil. A total of 60 benthic macroinvertebrate taxa were identified, the dominant group being the aquatic insects, with 50 families distributed in 8 orders. The dry period presented higher values of taxonomic richness and total density of benthic macroinvertebrates. A decreasing gradient was observed in these variable values from the 3rd order stretch down to the 6th order stretch. The highest Shannon-Wiener diversity values were found in the rainy period in the 3rd order stretches, which presented well-developed riparian forest. Besides the 3rd order stretches, the Pielou evenness index values were also high in the 6th order stretch. The collectors, together with the scrapers, predominated in the benthic macroinvertebrate communities in all river stretches, except in the 2nd, 4th, and 5th order stretches in the rainy period, where communities were dominated by filterers. The shredders and predators presented low densities for all river stretches. All microbiological variables presented low levels. Due to the high counts of heterotrophic bacteria and coliforms, the studied river stretches presented inadequate potability but adequate balneability levels. The results suggest that the structure, diversity, and composition of the benthic macroinvertebrate communities are influenced by the trophic resource availability, seasonality, and sediment heterogeneity. The microbiological results of this study allow inferring that the waters from Serra do Cipo have excellent potential for recreational use and as future sources of water for human consumption.

/pdf/diversity-assessment-of-benthic-macroinvertebrates-yeasts-3e3qcq11tr.pdf

Diversity assessment of benthic macroinvertebrates, yeasts, and microbiological indicators along a longitudinal gradient in Serra do Cipó, Brazil

The diversity and composition of drift invertebrate assemblages were evaluated along a longitudinal gradient of an altitudinal stream in southeastern Brazil. The main goal of this study was to evaluate the influence of seasonality, stream order, and some abiotic factors on invertebrate drift and the use of drifting invertebrate assemblages to assess aquatic invertebrate diversity. Drift samples were collected over a 24 h period using nets (open area of 0.08 m2; mesh 0.250 mm), partially submerged (60%) in the water column. Taxonomic richness, Pielou evenness (J), Shannon–Wiener diversity (H′), and total density of drift invertebrate assemblages were used in unpaired t-tests, Kruskal–Wallis and stepwise multiple regression analysis. The results showed a high taxonomic richness of aquatic invertebrates, with 91 taxa found. Chironomidae and Ephemeroptera represented together c. 80% of the total density of drift organisms. The drift approach allowed the collection of new and rare taxa, besides the knowledge of pupae stage of several chironomid genera. Significant differences in the taxonomic richness and diversity of drift invertebrate assemblages were found between the rainy and dry periods, indicating a significant influence of seasonality. An increase in water flow and electrical conductivity were associated with the increase in the taxonomic richness and diversity in the rainy period. No significant differences were found among the other abiotic variables among the stream orders.

/pdf/invertebrate-drift-along-a-longitudinal-gradient-in-a-sn56rjtvv5.pdf

M. Goulart

Papers

Macroinvertebrados Bentônicos como Ferramenta para Avaliar a Saúde de Riachos

Aplicação de um protocolo de avaliação rápida da diversidade de habitats em atividade de ensino e pesquisa (MG-RJ)

Biodiversity assessment of benthic macroinvertebrates along a reservoir cascade in the lower São Francisco river (northeastern Brazil)

Diversity assessment of benthic macroinvertebrates, yeasts, and microbiological indicators along a longitudinal gradient in Serra do Cipó, Brazil

Invertebrate drift along a longitudinal gradient in a Neotropical stream in Serra do Cipó National Park, Brazil