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1.
Mar Pollut Bull ; 156: 111174, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32510356

RESUMO

Globally, oxygen concentration in many coastal areas is depleting. River nutrient discharges may produce hypoxia events. The Southern Gulf of Mexico receives the discharges of the Grijalva-Usumacinta River System, the second largest in the Gulf of Mexico. To evaluate the influence of river discharges on dissolved oxygen concentrations in the receiving coastal ecosystem, we studied the variation of physicochemical variables in the water column. During the dry season, the influence of the river waters to the coastal area is scarce, but during the rainy season the river plume reached ~9 km offshore. The lowest concentration of dissolved oxygen (3.6 mg L-1) was observed within the river plume. We concluded that, in the studied area, hypoxia events (oxygen concentrations ≤ 2 mg L-1) would occur during the rainy season, low winds and in deeper waters (>80 m depth).

2.
PLoS One ; 14(1): e0210631, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30699162

RESUMO

A 35-year record of algal blooms in Mazatlan Bay is reviewed in order to register bloom-forming species and their seasonal presence, duration, degree of toxicity and environmental impact. A total of 202 algal blooms have been recorded and 25 dominant species identified: 6 toxic, 5 harmful and 14 harmless species. A harmless species, Myrionecta rubra, tended to decrease in frequency, while toxic species Gymnodinium catenatum and Margalefidinium polykrikoides showed a clear trend towards an increase in frequency. The number of discoloration days attributable to blooms was highly variable in each year, but a decadal analysis revealed a tendency to increase. The monthly distribution of algal blooms for decades showed two peaks of high frequency, the larger from February to May and the smaller from September to November. The duration of blooms varied from a few days to more than three months; the ephemeral blooms were the most frequent, but in the last decade, the frequency of the longer-lasting blooms has increased. An absence of blooms in 1983-4 and 1992-3 coincided with strong El Niño events, but this pattern was not consistent in subsequent El Niño years. Years with more or fewer discolorations days appear to be associated with cold or warm phases of the Pacific Decadal Oscillation.


Assuntos
Proliferação Nociva de Algas , Baías , Dinoflagelados/crescimento & desenvolvimento , Monitoramento Ambiental/história , História do Século XX , História do Século XXI , México
3.
Sci Total Environ ; 621: 548-557, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29195203

RESUMO

To evaluate the relationship of changes in organic-walled dinoflagellate cyst (dinocyst) fluxes to sediments with environmental variables (air and sea surface temperatures, El Niño conditions, rainfall, and terrigenous index), cyst assemblages were analyzed in a 210Pb-dated sediment core (~100years) from the pristine San José Lagoon (San José Island, SW Gulf of California). The dinocyst abundance ranged from 3784 to 25,108cystsg-1 and fluxes were of the order of 103-104cystscm-2yr-1. Lingulodinium machaerophorum, Polysphaeridium zoharyi and Spiniferites taxa accounted for 96% of the total dinocyst assemblages, and the abundances of these species increased towards the core surface. P. zoharyi fluxes increased from about 1965 onwards. Redundancy analyses, showed that mean minimum air temperature and terrigenous index were the key factors governing dinocyst fluxes. In this study, dinocyst fluxes of dominant taxa had responded to changes in climate-dependent environmental variables during the past ~20years; this may also be the case in other subtropical coastal lagoons.


Assuntos
Clima , Dinoflagelados/crescimento & desenvolvimento , Monitoramento Ambiental , Sedimentos Geológicos , California , Oceano Pacífico , Temperatura
4.
Salud Publica Mex ; 57(4): 343-51, 2015.
Artigo em Espanhol | MEDLINE | ID: mdl-26395800

RESUMO

OBJECTIVE: Pyrodinium bahamense monitoring in water and their toxins in rock oyster Striostrea prismatica in Santiago Astata and Puerto Escondido Oaxaca was performed from September 2009 to July 2010. MATERIALS AND METHODS: Pyrodinium bahamense abundance in water, and concentration and toxic profile of paralytic shellfish toxins were analyzed monthly in soft tissue of mollusk in composite samples in high performance liquid chromatography. RESULTS: High abundance of Pyrodinium bahamense was found in Santiago Astata on December, February, April and June; and in Puerto Escondido on April and June. The concentrations of the paralyzing toxin that exceeded the regulatory limit for human consumption of mollusks (800 µg STX eq. kg⁻¹) were presented in Santiago Astata on November, December, January, February and June; and in Puerto Escondido on December and June. CONCLUSIONS: For several months there was risk to public health due to the presence of paralytic shellfish toxins above the regulatory limit in oysters from the study area.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Proliferação Nociva de Algas , Toxinas Marinhas/análise , Ostreidae/química , Alimentos Marinhos/análise , Água do Mar/química , Animais , Cromatografia Líquida de Alta Pressão , Dinoflagelados/metabolismo , Concentração Máxima Permitida , Oceano Pacífico
5.
Salud pública Méx ; 57(4): 343-351, jul.-ago. 2015. ilus, tab
Artigo em Espanhol | LILACS-Express | ID: lil-760499

RESUMO

Objetivo. Monitorear el dinoflagelado Pyrodinium bahamense y sus toxinas en ostión de roca Striostrea prismatica en Santiago Astata y en Puerto Escondido, Oaxaca, de septiembre de 2009 a junio de 2010. Material y métodos. Se analizó mensualmente la abundancia de Pyrodinium bahamense mediante el método de Sedgewick-Rafter y la concentración de toxinas paralizantes y perfil tóxico en tejido blando del molusco en muestras compuestas de cada zona por el método de cromatografía líquida de alta resolución. Resultados. Se encontró alta abundancia de Pyrodinium bahamense en Santiago Astata en diciembre, febrero, abril y junio, y en Puerto Escondido en abril y junio. Los niveles de toxinas paralizantes fueron superiores al límite permisible para consumo humano en Santiago Astata en noviembre, diciembre, enero, febrero y junio; en la zona de Puerto Escondido, en diciembre y junio. Conclusiones. Estos niveles de toxinas representaron riesgo para la salud pública en la zona de estudio.


Objective. Pyrodinium bahamense monitoring in water and their toxins in rock oyster Striostrea prismatica in Santiago Astata and Puerto Escondido Oaxaca was performed from September 2009 to July 2010. Materials and methods. Pyrodinium bahamense abundance in water, and concentration and toxic profile of paralytic shellfish toxins were analyzed monthly in soft tissue of mollusk in composite samples in high performance liquid chromatography. Results. High abundance of Pyrodinium bahamense was found in Santiago Astata on December, February, April and June; and in Puerto Escondido on April and June. The concentrations of the paralyzing toxin that exceeded the regulatory limit for human consumption of mollusks (800 µg STX eq. kg-1) were presented in Santiago Astata on November, December, January, February and June; and in Puerto Escondido on December and June. Conclusions. For several months there was risk to public health due to the presence of paralytic shellfish toxins above the regulatory limit in oysters from the study area.

6.
Mar Drugs ; 10(5): 1044-65, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22822356

RESUMO

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.


Assuntos
Dinoflagelados/metabolismo , Toxinas Marinhas/toxicidade , Paralisia/induzido quimicamente , Pectinidae/efeitos dos fármacos , Pectinidae/metabolismo , Animais , Biotransformação , Cromatografia Líquida de Alta Pressão/métodos , Métodos de Alimentação , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Brânquias/patologia , Hemócitos/metabolismo , Hemócitos/patologia , Hidrólise , Cinética , Toxinas Marinhas/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Paralisia/metabolismo , Frutos do Mar
7.
Bull Environ Contam Toxicol ; 87(3): 272-5, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21748472

RESUMO

In order to determine the metal concentrations in cultured oysters from four coastal lagoons from SE Gulf of California, several individuals of Crassostrea gigas and C. corteziensis were collected and their cadmium, copper, lead and zinc levels were measured by atomic absorption spectrometry after acid digestion. The concentration of metals in oyster soft tissue was Zn > Cu > Cd > Pb. In two lagoons, Cd concentrations (10.1-13.5 µg g(-1) dw) exceeded the maximum level allowed according to the Official Mexican Standard (NOM-031-SSA1-1993), which is equivalent to the WHO recommended Cd levels in organisms used for human consumption.


Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Ostreidae/efeitos dos fármacos , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Animais , Cádmio/metabolismo , Clima , Cobre/metabolismo , Monitoramento Ambiental , Contaminação de Alimentos/análise , Sedimentos Geológicos/química , Humanos , México , Ostreidae/metabolismo , Alimentos Marinhos/análise , Alimentos Marinhos/toxicidade , Espectrofotometria Atômica/métodos , Poluentes Químicos da Água/metabolismo , Zinco/metabolismo
8.
Environ Toxicol ; 25(4): 319-26, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19437451

RESUMO

The dinoflagellate Cochlodinium polykrikoides isolated from Bahía de La Paz, Gulf of California, showed an important short-term toxic effect on the spotted rose snapper Lutjanus guttatus. This microalga was able to decrease fish liver catalase activity and lipid peroxidation. Fish exposed to live dinoflagellates developed an abnormal mucus secretion on the gills that was directly related to algal cell concentration. Hepatic catalase inhibition and an increase in mucus secretion on the gills occurred when fish were exposed to 2 x 10(6) cells L(-1) of C. polykrikoides. Lipid peroxidation was significantly different at 4 x 10(6) cells L(-1) and the hepatosomatic index decreased at 3 x 10(6) cells L(-1). Our results suggest that oxidative stress contributes, at least in part, to the ichthyotoxic effect of C. polykrikoides from the Gulf of California.


Assuntos
Dinoflagelados/patogenicidade , Peixes/parasitologia , Proliferação Nociva de Algas , Toxinas Marinhas/toxicidade , Estresse Oxidativo , Animais , California , Brânquias/anormalidades , Peroxidação de Lipídeos , Muco , Água do Mar
9.
Mar Pollut Bull ; 58(9): 1401-5, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19616264

RESUMO

The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahía de La Paz, Gulf of California was investigated as part of the ichthyotoxic mechanism of this microalga. Two different kinds of erythrocytes, fish and human, were tested for the hemolytic assay. Since fatty acids have been associated with hemolytic activity in C. polykrikoides, the composition of fatty acids of this dinoflagellate was also analyzed. The concentration of C. polykrikoides causing 50% hemolysis (HE(50)) was 4.88 and 5.27x10(6) cellsL(-1), for fish and human erythrocytes, respectively. According to the standard curve of saponin, an equivalence between the hemolytic activity of saponin and the dinoflagellate concentration was found with 1mug saponinmL(-1) equivalent to 1x10(6) cellsL(-1) of C. polykrikoides. The polyunsaturated fatty acids: hexadecaenoic (16:0), docosahexaenoic (22:6 n3) and octadecapentaenoic (18:5 n3) were found in an abundance of approximately 62% of total fatty acids.


Assuntos
Dinoflagelados/isolamento & purificação , Ácidos Graxos Insaturados/química , Hemólise , Toxinas Marinhas/toxicidade , Água do Mar/parasitologia , Animais , Dinoflagelados/química , Dinoflagelados/patogenicidade , Eritrócitos/efeitos dos fármacos , Peixes/sangue , Humanos , Toxinas Marinhas/isolamento & purificação , Toxinas Marinhas/metabolismo , Oceano Pacífico , Saponinas/metabolismo , Testes de Toxicidade
10.
Artigo em Inglês | MEDLINE | ID: mdl-17680474

RESUMO

Harmful Algal Blooms (HABs) are becoming an increasing problem to human health and environment (including effects on natural and cultured resources, tourism and ecosystems) all over the world. In Mexico a number of human fatalities and important economic losses have occurred in the last 30 years because of these events. There are about 70 species of planktonic and non-planktonic microalgae considered harmful in Mexican coasts. The most important toxin-producing species are the dinoflagellates Gymnodinium catenatum and Pyrodinium bahamense var. compressum, in the Mexican Pacific, and Karenia brevis in the Gulf of Mexico, and consequently the poisonings documented in Mexico are Paralytic Shellfish Poisoning (PSP) and Neurotoxic Shellfish Poisoning (NSP). Although there is evidence that Amnesic Shellfish Poisoning (ASP), Diarrhetic Shellfish Poisoning (DSP) and Ciguatera Fish Poisoning (CFP) also occur in Mexico, these problems are reported less frequently. The type of phytoplankton and epiphytic microalgae, their toxins and harmful effects as well as current methodology used to study these phenomena are presented in this paper. As an experienced group of workers, we include descriptions of monitoring and mitigation programs, our proposals for collaborative projects and perspectives on future research.


Assuntos
Toxinas Marinhas/toxicidade , Animais , Cianobactérias , Dinoflagelados , Eucariotos , Humanos , México , Fitoplâncton , Água do Mar
11.
Rev Latinoam Microbiol ; 47(1-2): 6-10, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-17061541

RESUMO

A dinoflagellate bloom ("red tide" event) dominated by the toxic Gymnodinium catenatum Graham (Gymnodiniales, Dinophyceae; 99.7%) and the noxious Noctiluca scintillans (Mcartney) Kofoid (Noctilucaceae, Dinophyceae; 0.3%) was observed in Bahia de Mazatlán Bay, México, on 24-26 January 2000. Photographic and microscopic analysis of samples during such an event, allowed us to collect evidence of a marked The particularity of grazing of G. catrenatum by by N. scintillans cells, suggesting a mechanism of "biocontrol" between these species that may contribute to attenuate a potentially toxic phenomenon under natural conditions.


Assuntos
Dinoflagelados/fisiologia , Animais , Conceitos Meteorológicos , Oceano Pacífico , Água do Mar , Especificidade da Espécie , Temperatura
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