Macroinvertebrates associated with Chara in a tropical coastal lagoon (Imboassica lagoon,Rio de Janeiro,Brazil)

Imboassica lagoon is an urban coastal lagoon located in the municipality of Macaé (RJ), which has been exposed to a process of artificial eutrophication through the inflow of untreated sewage, as well as artificial openings of the sandbar that separates it from the ocean, provoking drastic modifications in this ecosystem. The sampling for the analysis of the community of macroinvertebrates associated with Charopyceae (Chara angolensis e C. fibrosa) were performed between October 1995 and October 1997, with a total of 9 samplings at two sampling stations: one located in the innermost area of the lagoon and another at the mouth of the main sewage channel, close to the sandbar. Throughout this period, four artificial sandbar-opening events were recorded, resulting in changes in the biomass of the macroalgae and in the densities of the macroinvertebrate populations. Through the analysis of the density of organisms per square meter, and density of organisms per 100 g dry weight of Chara, it was established that the biomass of the macroalgae has a direct influence on the density of the associated macrofauna. The greater development of the periphytic community in the area close to the inflow of sewage allows for the development of a community of macroinvertebrates with high densities, composed mainly of scraping organisms, such as the mollusc Heleobia australis (Hidrobiidae).     

Eleocharis mutata (L.) Roem. et Schult. subject to drawdowns in a tropical coastal lagoon,State of Rio de Janeiro,Brazil

This investigation of the aquatic macrophyte Eleocharis mutata (L.) Roem. Et Schult. was carried out in Imboassica lagoon, a coastal lagoon in Macaé (22°50S; 44°42W), in the northern part of Rio de Janeiro, Brazil. The sandbar separating this lagoon from the ocean has been opened several times for flood control and to allow the entrance of marine species of commercial interest. The barrier bar has been breached without appropriate planning, and the consequences of breaching for the lagoon ecosystem are poorly understood. These openings drastically affect the structure and functioning of the lagoon, but there are no data on possible effects on macrophyte communities. In this project, we obtained data on the increase of the distribution, biomass accumulation and production rates of E. mutata in the establishment of a new stand, in an effort to relate effects of sandbar breach events to the expansion of this species. During 22 months of sampling, 4 breachings of the sandbar occurred, and E. mutata increased its area of coverage by about 810⁴ m², or 2.5% of the total area of the lagoon. The total aerial biomass reached a maximum of 1515 g DW m^–2, and the underground biomass reached 583 g DW m^–2. During the establishment and development of the stand, both dead and live aerial biomass and underground biomass tended to accumulate. Aerial net primary production (ANPP) was quite variable, reaching a maximum of 18.9 g DW m^–2 d^–1. We conclude that the sudden variations in water level caused by breaches in the sandbar were beneficial to the expansion of this species in Imboassica lagoon.     

Bioavailability of heavy metals in sediments of two coastal lagoons in Rio de Janeiro,Brazil

The distribution and bioavailability of trace metals in two contrasting tropical coastal lagoons were studied. The concentration of trace metals in aquatic macrophytes was compared with those found in sediments under weakly and strongly bound forms. The results showed that total metal concentrations in sediments did not explain the concentration found in plants. The highest concentrations in macrophytes were observed in the lagoon which had a higher fraction of metals weakly bound to sediments, but presented the lower total metal content. Low redox potential was the major variable keeping metals in non-bioavailable forms, possibly as refractory sulfides and metal-organic complexes. Among the macrophytes, rooted species showed lower concentrations of metals as compared to algae.     

Description of Macrochaetus kostei n.sp (Rotifera,Trichotriidae) from a coastal lagoon of Rio de Janeiro,Brazil

A new rotifer is described and figured based on females taken from Comprida lagoon, Rio de Janeiro State, in southeastern Brazil. This new animal belongs to the Genus Macrochaetus which includes several species recorded in South America. A key to species of the Genus Macrochaetus of the Neotropical Region is presented.     

Microcosm analysis of salinity effects on coastal lagoon plankton assemblages

A microcosm experiment was conducted to assess the effects of salinity on coastal lagoon plankton assemblages. Five salinity levels were replicated four-fold in 3801 fiberglass tanks. Salinity levels used were 0, 8.5, 17, 34 and 51 ppt, or 0, 25, 50, 100 and 150 percent seawater. These were achieved by mixing concentrated lagoon water and tapwater in different proportions. Tanks were inoculated with plankton collected from San Dieguito Lagoon (Del Mar, San Diego County, California) and other fresh and saline waterbodies in the area. Selected physical-chemical variables, phytoplankton, zooplankton, and other invertebrate populations were monitored on five sampling dates over a 114 day period (13 August–5 December 1986).Total phytoplankton abundance increased with salinity, for salinities >17 ppt. Most taxa showed marked effects of salinity, though the pattern of the effects often varied greatly from date to date. Chlorophytes tended to be most abundant at 51 ppt. Pyrrhophytes were most abundant at 0 or 51 ppt, and least abundant at 8.5 or 17 ppt. Cryptophytes increased with increasing salinity. Euglenophytes exhibited no salinity effect on any date. Bacillariophytes were most abundant at 8.5–34 ppt and least abundant at 51 ppt, with individual taxa showing maxima at 0–17 ppt (Navicula, Synedra), 8.5–34 ppt (Surirella, Amphora), and 34 ppt (Cylindrotheca).Total zooplankton abundance decreased with salinity, for salinities > 17 ppt. The dominant taxa were protozoans, rotifers, cladocerans, and copepods, and all but the first group showed strong salinity effects. Protozoan abundance was unaffected by salinity. Rotifers were most abundant at 0 ppt (Keratella, Filinia) or 8.5 ppt (Brachionus). With few exceptions, cladocerans (Alona, Ceriodaphnia, Scapholeberis) were found only at 0 ppt. Abundance of calanoid copepods decreased with increasing salinity, with individual taxa showing maxima at 0 ppt (Diaptomus), 8.5–17 ppt (Pseudodiaptomus, Eurytemora), and 34 ppt (Acartia). Cyclopoid copepods were most abundant at 17 ppt, with individual taxa showing maxima at 0 ppt (Eucyclops), 8.5 ppt (Halicyclops), and 17 ppt (Oithona). Harpacticoid copepods (Cletocamptus, Tachidius) were most abundant at 17–34 ppt. Ostracods and mosquito (Culex) larvae were most abundant at 8.5 ppt and absent at 34 and 51 ppt. Polychaetes generally were most abundant at 17–34 ppt, and water boatmen (Trichocorixa) at 8.5–34 ppt. Various physical and chemical variables also showed significant variations with salinity. Tending to increase with salinity were temperature, ammonia and orthophosphate concentrations. Decreasing with salinity were pH, dissolved oxygen and silica concentrations. The causes and interrelationships of these salinity effects are discussed.     

Modern benthic diatom distribution in a hypersaline coastal lagoon: the Lagoa de Araruama (R.J.), Brazil

Diatom assemblages identified in 75 surface sediment samples in a shallow hypersaline coastal lagoon (Lagoa de Araruama, R.J., Brazil) are mainly composed of holo-euryhaline and marine euryhaline benthic taxa. The lagoon is characterized by an assemblage dominated by Cocconeis placentula var. euglypta, associated with Catenula adhaerens and Cocconeis diminuta. However, different areas, characterized by specific assemblages, have been identified. Their distribution seems to be related to (1) fluctuations in bathymetry, influenced by water inputs from the ocean and from rivers adjacent to the lagoon; (2) fluctuations in salinity through the influence of marine water and the precipitation–evaporation rate. Moreover, the distribution of associations characterized by the presence of Nitzschia palea, N. pusilla and Fallacia cryptolyra suggests the influence of man-induced activities. Although these diatoms are not dominant, their wide distribution inside the lagoon, favored by local wind-hydrodynamics, suggest a large impact of anthropic activities (e.g. freshwater and organic sewages).     

Chronic pulmonary histoplasmosis in the State of Rio de Janeiro,Brazil

Three cases of chronic pulmonary histoplasmosis affecting aged patients with chronic obstructive pulmonary disease are reported. They had a history of recurrent episodes of respiratory infection and presented radiological lung lesions inducing a misdiagnosis of chronic pulmonary tuberculosis of the adults. The diagnosis of histoplasmosis, suggested by the immunodiffusion test and the detection of yeastlike cells in smeared and stained sputum, was confirmed by the isolation and identification of Histoplasma capsulatum var. capsulatum in selective media. The treatment was carried out with amphothericin B and ketoconazole or itraconazole. Clinical, radiologic, mycologic and serologic improvement was obtained in all the patients. However, relapses occurred within a period of 1 to 18 months after the interruption of the treatment. Mycological diagnosis and the difficulties observed in the tretament were discussed. In addition data on the epidemiology of histoplasmosis in the state of Rio de Janeiro, Brazil, were presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evaluation of the nutrient inputs to a coastal lagoon: the case of the Ria de Aveiro,Portugal

The Ria de Aveiro estuary-coastal lagoon system of northern Portugal is estimated to currently receive mean annual influxes of total nitrogen (N) and total phosphorus (P) of c. 6118 t y^–1 and 779 t y^–1, respectively, from its influent rivers. In low summer flows the mean N and P fluxes decrease to c. 10% of the annual average. The sewage contribution to the inland-derived N load on an annual basis is c. 5% but, during the summer low flow conditions, the sewage component increases to c. 65% of the total river loading. The sewage contribution to the inland-derived P load on an annual basis is c. 11% but, during the dry season, it is 1.2 times larger than the river-derived flux. The construction of a regional sewer system linked to a submarine outfall, due for completion in 2005, is expected to lead to a reduction in nutrient fluxes from inland to the lagoon of c. 15% for N and c. 26% for P relative to the present values. While this system will reduce the nutrient loading in the upper reaches of the lagoon, an increase in nutrients derived from the ocean is anticipated, due to the proximity of the outfall to the inlet.     

Evolution saisonniere du zooplancton dans trois sites peu profonds de Thau,une lagune Nord-Mediterraneenne

A monthly zooplankton survey has been conducted from March 1982 to March 1983 at three shallow stations of Thau, a northern-mediterranean lagoon. These stations differ by their distance from the entry of sea-water in the lagoon. Parameters such as pH, temperature, dissolved oxygen, conductivity and turbidity have been measured simultaneously with the sampling in the same water layer. The zooplankton collected corresponds to species usually found in marine neritic communities. In the spring, species richness is maximum. During the summer, meroplankton forms dominant populations in the communities. Autumn is marked by a reduction of the number of species and of the abundance in both components, holoplankton and meroplankton. Few species are present in the winter holoplankton while meroplankton disappears practically from the samples. The sites under observation are subjected to unpredictable changes, in water movement as well as in the organization of the zooplankton communities. These modifications are strongly influenced by weather conditions.     

Insecticide resistance and genetic structure of Aedes aegypti populations from Rio de Janeiro State,Brazil

Vector control largely relies on neurotoxic chemicals, and insecticide resistance (IR) directly threatens their effectiveness. In some cases, specific alleles cause IR, and knowledge of the genetic diversity and gene flow among mosquito populations is crucial to track their arrival, rise, and spread. Here we evaluated Aedes aegypti populations’ susceptibility status, collected in 2016 from six different municipalities of Rio de Janeiro state (RJ), to temephos, pyriproxyfen, malathion, and deltamethrin. We collected eggs of Ae. aegypti in Campos dos Goytacazes (Cgy), Itaperuna (Ipn), Iguaba Grande (Igg), Itaboraí (Ibr), Mangaratiba (Mgr), and Vassouras (Vsr). We followed the World Health Organization (WHO) guidelines and investigated the degree of susceptibility/resistance of mosquitoes to these insecticides. We used the Rockefeller strain as a susceptible positive control. We genotyped the V1016I and F1534C knockdown resistance (kdr) alleles using qPCR TaqMan SNP genotyping assay. Besides, with the use of Ae. aegypti SNP-chip, we performed genomic population analyses by genotyping more than 15,000 biallelic SNPs in mosquitoes from each population. We added previous data from populations from other countries to evaluate the ancestry of RJ populations.All RJ Ae. aegypti populations were susceptible to pyriproxyfen and malathion and highly resistant to deltamethrin. The resistance ratios for temephos was below 3,0 in Cgy, Ibr, and Igg populations, representing the lowest rates since IR monitoring started in this Brazilian region. We found the kdr alleles in high frequencies in all populations, partially justifying the observed resistance to pyrethroid. Population genetics analysis showed that Ae. aegypti revealed potential higher migration among some RJ localities and low genetic structure for most of them. Future population genetic studies, together with IR data in Ae aegypti on a broader scale, can help us predict the gene flow within and among the Brazilian States, allowing us to track the dynamics of arrival and changes in the frequency of IR alleles, and providing critical information to improving vector control program.     

mtDNA ancestry of Rio de Janeiro population,Brazil

Polymorphism studies concerning HVI and HVII regions of mitochondrial DNA (mtDNA) have improved the understanding of the admixture genetic process related to the occupation of the continents by human population groups. We have analyzed the mtDNA lineages of 190 healthy and maternally unrelated individuals born in the metropolitan region of the Rio de Janeiro city, the capital of the State of Rio de Janeiro, southeastern Brazil. The data showing that 57.9, 25.3 and 16.8 % of the matrilineages found in Rio de Janeiro come from African, Amerindian and European population groups. They are, respectively, in close agreement with historical records which indicate that the admixture population of Brazil is the resulting of interethnic asymmetry crosses between individuals from those population groups. The high proportion of African mtDNA lineages in the population of Rio de Janeiro is in accordance with studies related to other Brazilian states.     

Dengue in the State of Rio de Janeiro, Brazil, 1986-1998.

This paper presents epidemiological, laboratory, and clinical data on 12 years of dengue virus activity in the State of Rio de Janeiro from the time the disease was first confirmed virologically in April 1986 through April 1998. DEN-1 and DEN-2 viruses are the serotypes circulating in the state and were responsible for the epidemics reported during the last 12 years. The results published here show both the impact of dengue virus infections on the population and laboratory advances that have improved dengue diagnosis.     

Effects of sand bar openings on some limnological variables in a hypertrophic tropical coastal lagoon of Brazil

This study describes the spatial and temporal dynamics of several physical, chemical and biological variables in the Grussai lagoon, and their relationship to ephemeral sand bar openings and to a constant in natura waste water input. The spatial variation in pH, dissolved oxygen, electrical conductivity, total alkalinity and nutrients (e.g. soluble reactive silicate, soluble reactive phosphate and ammonium) was associated to the anoxic and nutrient rich groundwater discharge, the development of aquatic macrophytes, the biological activities of phytoplanktonic community and the marine influence. During the period when the sand bar was closed (isolated), the lagoon water was supersaturated with dissolved oxygen and exhibited high values of pH (8–10), total alkalinity (3.000–5.000 μeq l^-1), and chlorophyll a contents (60-300 μg l^-1), and had low values of dissolved nutrients (nearly undetectable). These suggest a biological processes dominance. When the sand bar was opened, there was an enrichment with dissolved inorganic nutrients (e.g. ammonium and soluble reactive phosphorus up to 120 and 5 μM, respectively) and a decrease in pH (below 8), total alkalinity (below 3.000 μeq l^-1) and dissolved oxygen during the initial second to eight days. Subsequently there was a period when the physical and chemical characteristics of seawater prevailed. The lagoon returned chemical to the pre-opening water conditions in a few days (∼ 10–20). This quick return implies highly efficient biological mechanisms. The high levels of chlorophyll a, total nitrogen and phosphorus in the water column indicate a high eutrophication stage in the Grussai lagoon during the sand bar closed periods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of a eutrophic coastal lagoon ecosystem from the study of bottom sediments

Morphological reconstruction and biogeochemical characterisation of the lagoon of Comacchio (Italy) were carried out in order to provide recommendations for the recovery, conservation and sustainable management of the Fattibello-Spavola coastal lagoon ecosystem. Samples were taken in two seasons: July 1997 and November 1998. The irregular morphology of the Fattibello lagoon affects depositional processes and seawater exchange (tidal currents). Several depressions retain part of the dense water of the saline wedge; these stagnant waters became sinks for fine terrigenous and organic matter. The basin is already extensively supplied with N and P compounds from land. The inflow is demonstrated by the large quantity of organic C, N and organic and inorganic P compounds in the superficial sediment. The ratios between the various forms of macronutrients indicate that the organic matter is primarily of autochthonous origin, with relatively low C/N ratios (8.4±0.6 and 8.1±0.6 in July and November, respectively). Shallow areas were almost always oxygenated by tidal currents and thus rich in organisms, with a predominance of molluscs and Ficopomatus enigmaticus. However, the trophic equilibrium of the ecosystem was affected by the accumulation of organic matter in the depressions, favoured by the increased hydrodynamics during the autumn. These accumulations generate high oxygen consumption and release considerable quantities of nutrients into the water column, with the risk of serious dystrophy throughout the basin during the summer. Local dredging and an improvement of the circulation have been suggested and carried out to contain these processes. Reclamation measures in the longer term were proposed.     

Seasonal and areal features of the lagoonal environment in Lake Nakanoumi,a shallow coastal lagoon in Japan

Lake Nakanoumi is a shallow coastal lagoon connected with the Japan Sea by a narrow channel. Over the past decade, land reclamation resulted in a 33% reduction of the lagoon's surface area. The remaining water basin of Lake Nakanoumi is scheduled to be artificially freshened to supply irrigation water for the newly reclaimed lands. This paper deals with the seasonal and areal features of the lagoonal environment prior to the beginning of the artificial desalinization.     

Ammonification rates and 210Pb in sediments from a lagoon under a wet tropical climate: Marica,Rio de Janeiro state,Brazil

The ammonification rates in surficial sediments of the Marica lagoon (Rio de Janeiro, Brazil) were estimated using two methods:

Bone sporotrichosis: 41 cases from a reference hospital in Rio de Janeiro,Brazil

BackgroundBone sporotrichosis is rare. The metropolitan region of Rio de Janeiro is hyperendemic for zoonotic sporotrichosis and the bone presentations are increasing.MethodsWe studied a retrospective cohort of 41 cases of bone sporotrichosis, diagnosed from 1999–2016. The inclusion criteria was fungal culture isolation from any clinical specimen associated to bone involvement (radiography and/or computed tomography) compatible with fungal osteomyelitis or histopathological findings of bone material compatible with sporotrichosis. Molecular identification was performed when possible.ResultsMale patients represented 58.5% of the cases, with a cohort median age of 43 years. Immunosuppressive conditions were present in 68.3% of the patients, mostly HIV coinfection (51.2%). Multifocal bone involvement (more than one anatomical segment) was diagnosed in 61% of the patients, while 39% presented unifocal involvement. The bones of the hands were the most affected (58.5%), followed by the feet (41.5%) and tibia (26.8%). Multifocal group was characterized by a higher proportion of males (p = 0.0045) with immunosuppressive conditions (p = 0.0014). Amphotericin B followed by oral itraconazole was the main treatment, with a median time of 16.7 months (1.5 to 99.2 months), and cure of 53.7% of the patients (84.6% of immunocompetent and 39.3% of immunocompromised patients). Sequelae occurred in 12.2% of the patients—amputations (7.3%) and ankylosis (4.9%), while 22% died in the course of the disease. Sporothrix brasiliensis was the causative agent in all the 9 (22%) performed cases.ConclusionsBone sporotrichosis is a chronic, challenging condition with prolonged treatment, often with poor results and sequelae.