Papers by PATRICIA MACAROFF DOMINGOS
Algological Studies/Archiv für Hydrobiologie, Supplement Volumes, 2001
We describe phenotype characters of cyanobacterial populations, dominating in the Tabocas reservo... more We describe phenotype characters of cyanobacterial populations, dominating in the Tabocas reservoir, State of Pernambuco, Brazil, in the period February-June 1996. Massive development of cyanoprokaryotic species in the reservoir was then responsible for cyanotoxin production into the water. As a consequence, over 50 people died after intoxication by cyanotoxins in the hemodialysis center in Caruaru, Brazil. All the dominating cyanobacterial species from Tabocas reservoir belong exclusively to the tropical, not well known species. The basic phenotype descriptions and ecological characters ofAphanothece stratus, Romeria caruaru (spec, nova), Aphanocapsa cf. cumulus, Microcystis protocystis, M. panniformis, Chroococcidiopsis cf. indica and Aphanizomenon manguinii are included in the article. - Two important conclusions can be drawn from our results: (i) Numerous important specific and little known cyanobacterial types occur in tropical regions, different from these ones known from temperate zones, and (ii) the picoplanktic populations can be formed by cells liberated from macroscopic colonies of benthic and periphytic species. Our results support also the hypothesis about the toxicity of cyanobacteria from various taxonomic groups and various biotopes, and urge further study of the natural populations from little known tropical biotopes by combined traditional and modern molecular methods.
Cette étude porte sur la composition et la biomasse du phytoplancton d'une lagune tropicale e... more Cette étude porte sur la composition et la biomasse du phytoplancton d'une lagune tropicale eutrophisée (lagune de la Barra appartenant au système lagunaire Marica-Guarapina, Etat de Rio de Janeiro, Brésil). Elle a été réalisée conjointement à d'autres études sur le métabolisme de l'écosystème, la distribution des éléments biogéniques C, N et P et la communauté zooplanctonique. On analyse ici les relations entre le phytoplancton et une crise dystrophique, suivie d'une mortalité massive de poisssons qui a eu lieu en février 1991. La mortalité, qui a porté sur un poisson filtreur, #Brevoortia tyrannus$, a coïncidé avec une période de haute biomasse de #Cyanophyceae$ en phase de sénescence. L'hypothèse d'une intoxication de #B. tyrannus$ par #Synechocystis aqualitis f. salina$ est la plus probable. Cette étude a également permis d'analyser le succès des #Cyanophyceae$ et d'autres espèces de petite taille dans ce milieu. Il s'agit d'ailleurs d'...
Cette étude porte sur l'évolution des stocks des éléments biogéniques C, N et P (organiques e... more Cette étude porte sur l'évolution des stocks des éléments biogéniques C, N et P (organiques et minéraux, particulaires et dissous) de la lagune de la Barra (état de Rio de Janeiro, Brésil). Elle a été réalisée de la mi-printemps 1990 à la mi-automne 1991, conjointement avec des études sur le métabolisme du carbone et sur les communautés planctoniques. La première phase de la période étudiée, qui correspond au début de la saison chaude, a été marquée par un appauvrissement du milieu en azote par rapport au phosphore (rapport molaire NOP/POP du seston = 5,7). La perte de N, probablement due au processus de dénitrification, a conduit à une floraison de #Synechocystis aqualitis f. salina$. Ces organismes, mieux adaptés à la pénurie de N, auraient réduit leur sécrétion en azote organique dissous et aussi favorisé le recyclage de l'azote dans le milieu pélagique au détriment du milieu benthique. Selon certains indices, ils auraient fixé de l'azote moléculaire dissous; mais ce ...
La lagune de Saraquema, qui présente les caractéristiques d'un milieu fortement eutrophisé, e... more La lagune de Saraquema, qui présente les caractéristiques d'un milieu fortement eutrophisé, est dominée par une communauté nanoplanctonique (35% Cyanophycées et 45% Prymnesiophycées), très peu diversifiée (2,5 bits.ind.-1). Les brusques changements météorologiques et hydrologiques, dus aux arrivées de fronts polaires, renforcent la haute instabilité hydroclimatique de ce milieu d'interface continental-marin et accroissent son pouvoir de sélection des espèces, de sorte que ce sont celles de petites tailles (10 um3), à métabolisme rapide et à temps de régénération court, qui s'adaptent le mieux à cette situation. D'un jour à l'autre, tant les biomasses que les activités biologiques peuvent chuter de moitié sous les effets d'intrusions polaires, tandis que un ou deux jours plus tard elles peuvent retrouver leurs valeurs antérieures. Par ailleurs, les fronts froids qui ralentissent moins l'activité hétérotrophique que celle autotrophique conduisent à des phas...
Le métabolisme du carbone de la lagune de la Barra, déterminé par les variations nycthémérales du... more Le métabolisme du carbone de la lagune de la Barra, déterminé par les variations nycthémérales du contenu des eaux en CO2 total, corrigées des échanges gazeux de CO2 à l'interface eau-atmosphère, a été suivi de la mi-printemps 1990 à la mi-octobre 1991. Durant cette période, marquée par une mortalité massive de poissons, il présente un caractère fortement autotrophe, avec un taux de production de carbone organique de jour, P, égal à 194 plus ou moins 100 mmoles/m2 et un taux de minéralisation de nuit, M, de 141,5 plus ou moins 40 mmoles/m2 (n=27). Une analyse des facteurs de contrôle de P et M a été faite en fonction de données sur l'environnement physique du milieu, la dynamique des éléments biogéniques (carbone, azote et phosphore) et celle des communautés phyto et zooplanctonique. Le milieu, qui présente successivement une période fortement carencée en N, puis une période excédentaire en ce même élément (suite à une mortalité de poissons), a recours à différentes stratégi...
Phytoplankton and Trophic Gradients, 1998
We compared the structure and function of the phytoplankton community in three tropical systems i... more We compared the structure and function of the phytoplankton community in three tropical systems in Brazil: an oligo-mesotrophic floodplain lake; an eutrophic reservoir; and a hypereutrophic coastal lagoon. Phytoplankton biomass increased along this trophic gradient averaging 2.6, 6.2 and 31.6 mm 3 l 1 in the lake, reservoir and lagoon, respectively. Similarly, production increased from 427 to 918 gC m 2 y 1. Along the trophic gradient, diversity and species richness of phytoplankton decreased. There was, however, no relationship between trophy and rates of change of phytoplankton communities or the ratio of maximum/mean biomass. Phytoplankton size varied between systems with small algae (2-20 m) dominating in the hypereutrophic lagoon and larger algae (20-200 m) dominating in the other systems. Many of the trophic indices developed for temperate areas could not be applied to these tropical systems since there was no clear relationship between Secchi depth, chlorophyll, or TP and trophic status. Phytoplankton species may be more useful than these trophic indices to the classification of the condition of tropical lakes.
Interagir: pensando a extensão, 2014
Hydrobiologia, 2000
Cyanoprokaryote assemblages of eight very productive Brazilian lakes are described and the main d... more Cyanoprokaryote assemblages of eight very productive Brazilian lakes are described and the main driving forces of their dominance are considered. Relative abundance of blue-greens is shown to have been positively related to temperature, but not to pH or total-P and to have been negatively associated with light, mixing, NO 3 , but not with NH 4 , total N or total N/total P ratio. Both heterocytic and non-heterocytic groups were negatively related to NO 3. However, if Cylindrospermopsis species are considered as non-N 2-fixing organisms (only 10% of the filaments carried heterocytes), the lakes could be considered as dominated by non-N 2-fixing populations during most of the years. In this new scenario, non-N 2-fixing were dominant in NO 3 (but not NH 4) deficient lakes , and in both NO 3 and NH 4 deficient conditions. Assemblages S, S n, H, M, X 1 , as groups of descriptor species of systems having similar features as proposed by Reynolds (1997: Ecology Institute, Oldenburg), were representative of warm, shallow, turbid, enriched and frequently mixed lakes. We propose to move some species from Z (picoplancton of oligotrophic lakes) to X 1 assemblage (nanoplankton of eutrophic lakes) and we comment on Microcystis species of M assemblage from mixed shallow lakes in relation to L m assemblage of end-summer in temperate lakes. S and S n assemblages, which comprise species which are good-light antennae, were the best represented group in these generally turbid and shallow lakes.
Toxicon, 2003
Blooms of cyanobacteria in water bodies cause serious environmental problems and the occurrence o... more Blooms of cyanobacteria in water bodies cause serious environmental problems and the occurrence of toxic strains are also related with the human health. Aquatic animals could bioaccumulate microcystins (cyanobacteria hepatotoxins) and so, beyond water, the ingestion of contaminated food represents a human health risk. Recently, WHO recommended a maximum concentration of microcystins (MCYSTs) in drinking water and established the tolerable daily intake (TDI) for consumption of cyanobacteria products contends MCYSTs (0.04 mg 21 kg 21 day 21). Sepetiba Bay is located in the municipal districts of Rio de Janeiro, Mangaratiba and Itaguaí being an important place of fishing activity. Due to the industrial development in the area, this bay is submitted to different environmental impacts, increasing the organic and industrial pollution. A strain of the nanoplanktonic cyanobacteria Synechocystis aquatilis f. aquatilis that produce MCYSTs was already isolated. In this study, we verified MCYSTs presence in muscle tissue of fish and crustaceans, which were harvested monthly in Sepetiba Bay during 11 months, in order to evaluate the potential risk of their ingestion. MCYSTs were analyzed by immunoassay techniques using the ELISA Microcystin Plate Kit (ENVIROLOGIX INC w) and the concentration were expressed as microcystin-LR equivalent. The analyses of seston samples, water, muscle tissues showed the presence of this cyanotoxin in all samples and it was verified that 19% of the animals' samples were above the limit recommended by WHO for human consumption. The maximum value found was of 103.3 mg kg 21 (TDI 0.52 mg kg 21 day 21) and the minimum, was 0.25 mg kg 21 in crabs muscle tissue (TDI of 0.001 mg kg 21 day 21). Such data demonstrate that, although in low concentrations, there is already a contamination of fish and crustaceans from Sepetiba Bay. We highlight that the recommended limit refers to healthy adult.
Limnologica, 2002
Jacarepagufi Lagoon is a shallow, hypereutrophic, coastal lagoon located in Rio de Janeiro (RJ, B... more Jacarepagufi Lagoon is a shallow, hypereutrophic, coastal lagoon located in Rio de Janeiro (RJ, Brazil), with recurrent blooms of cyanobacteria. This study was carried out with the aim to detect the effects of the cyanobacterium Microcystis aeruginosa on zooplankton populations (especially cladocerans) in the lagoon. At two sampling stations we measured temperature, pH, salinity, dissolved oxygen and transparency, and collected water samples for chemical analyses of particulate organic carbon (POC), chlorophyll-a and toxins (microcystins), and plankton samples for phytoplankton and zooplankton analyses, from August 1996 to September 1997. Laboratory experiments were also performed to test for toxicity of both natural assemblages and cultured Microcystis. The results showed that temperature, salinity and cyanobacteria biomass were the best descriptors of the population dynamics of Cladocera. In spite of high levels of microcystins in seston, toxins were not generally correlated with the density of Cladocera. Laboratory experiments, however, showed strong evidence of the toxicity of seston to Cladocera. Also, high levels of toxins in seston were associated with a collapse of cladoceran populations in the lagoon, suggesting toxic effects of mycrocystins on these organisms. Rotifers and copepods were less affected by cyanobacteria, maintaining high densities in the lagoon throughout the bloom. We conclude that blooms of Microcystis aeruginosa are potentially harmful for cladoceran populations in nature.
Environmental Toxicology, 1999
Seven strains (NPCA-S,-10,-is,-16,-19,-23, and-29) of picoplanktonic cyanobacteria from Caruaru r... more Seven strains (NPCA-S,-10,-is,-16,-19,-23, and-29) of picoplanktonic cyanobacteria from Caruaru reservoirs were identified and analyzed for toxiCity. We tested the toxicity of these strains by mouse bioassay, by HPLC, and by enzyme-linked immunosorbent assay (ELISA). Strains NPCA-15 and-23 were toxic when tested by mouse bioassay (LD 100 =600 mgow/kg body weight). The toxin from strain NPCA-15 had the same UV spectrum as microcystin-LR. All of the strains showed the presence of microcystin by ELISA analysis. The microcystin concentration varied between 0.08 ng/mg Dw (NPCA-S) and 3.7 'lg/mg ow (NPCA-1S). Confirmation of microcystin production by picoplankton opens the possibility that these organisms may have contributed to human pOisoning in Caruaru and defines a new source of microcystin in water supplies.
Aquatic Ecosystem Health & Management, 2001
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Papers by PATRICIA MACAROFF DOMINGOS