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The genus Coolia A. Meunier 1919 has a global distribution and is a common member of epiphytic dinoflagellate assemblages in neritic ecosystems. Coolia monotis is the type species of the genus and was the only known species for 76 years. Over the past few decades, molecular characterization has unveiled two species complexes that group morphologically very similar species, so their limits are often unclear. To provide new knowledge on the biogeography and species composition of the genus Coolia, 16 strains were isolated from Bahía de La Paz, Gulf of California. The species were identified by applying morphological and molecular approaches. The morphometric characteristics of all isolated Coolia species were consistent with the original taxa descriptions. Phylogenetic analyses (large subunit [LSU] rDNA D1 / D2 and internal transcribed spacer [ITS] 1 / 5.8S / ITS2) revealed a species assemblage comprising Coolia malayensis, C. palmyrensis, C. tropicalis, and the C. cf. canariensis lineage. This is the first report of Coolia palmyrensis and C. cf. canariensis in Mexico and C. tropicalis in the Gulf of California. Our results strengthen the biogeographical understanding of these potentially harmful epiphytic dinoflagellate species.

It is well known that modern resting cysts with morphologies matching those of species of the fossil genus Spiniferites germinate into motile cells of the genus Gonyaulax. Different Spiniferites species have been connected to a single Gonyaulax species, raising the question of whether they are over-classified. Through germination experiments of cysts with the morphological features of four species of Spiniferites, viz. S. bentorii, S. hyperacanthus, S. ramosus and S. scabratus, we established cyst-theca relationships. Cysts with the morphology of S. bentorii gave rise to vegetative, motile cells of Gonyaulax nezaniae sp. nov., which is characterized by two stout antapical spines. Cysts with S. hyperacanthus and S. ramosus morphologies germinated into Gonyaulax whaseongensis and G. spinifera, respectively. Cysts with S. scabratus morphology lacked a ventral pore and were attributed to Gonyaulax cf. spinifera. Gene sequences for SSU, LSU and/or ITS-5.8S rRNA were obtained from these four species, and from cysts with the morphology of Spiniferites belerius, S. mirabilis, S. lazus, Spiniferites cf. bentorii and Tectatodinium pellitum. The maximum likelihood and Bayesian inference analyses based on LSU and SSU rRNA gene sequences revealed that cysts assignable to Spiniferites formed a polyphyletic group, intermingled with Tectatodinium, Bitectatodinium, Ataxiodinium and Impagidinium, whereas Gonyaulax species appeared as monophyletic. From our results we inferred the phylogenetic positions of S. bentorii, S. mirabilis, S. lazus, S. scabratus, Tectatodinium pellitum and Gonyaulax digitale for the first time, supporting the idea that Spiniferites species are not over-classified and each of them may correspond to different Gonyaulax species.

Excess supply of nutrients of anthropogenic origin is one of the main drivers of global change that is affecting the ecological function and provision of ecosystem services by coastal wetlands. This study examines the response of a subtropical semi-arid coastal lagoon to anthropogenic nutrient input, through the use and comparison of eutrophication indices and models, and compares the usefulness of such methods to identify eutrophication symptoms. The Lobos Lagoon is located on the eastern coast of the Gulf of California and receives agricultural and urban wastewater discharges. To identify potential eutrophication symptoms, the Trophic IndeX (TRIX), the Arid Zone Coastal Water Quality Index (AZCI) along with the Assessment of Estuarine Trophic Status (ASSETS) model were used. Lobos Lagoon was found to have good environmental condition; however eutrophication symptoms were identified in the zone where untreated urban and agricultural wastewaters are discharged. Results obtained using the three methods were consistent and, thus, their performance can be considered as good and complementary, and can be used to evaluate the extent of eutrophication in subtropical semi-arid coastal lagoons.

Understanding the susceptibility of coastal ecosystems to nutrient loads from anthropogenic sources and the extent of eutrophication in subtropical and tropical estuaries is still a challenge. This study assessed eutrophication in Guaymas Bay, a subtropical lagoon that receives nutrient-rich urban wastewater discharges. Eutrophication was evaluated by means of the Assessment of Estuarine Trophic Status model. Our results showed that the trophic status of Guaymas Bay was “good.” It is important to consider that: (1) the dissolved oxygen and chlorophyll a levels observed are indicative of a healthy ecosystem, and (2) the key factors explaining this finding are the high susceptibility to eutrophication of the lagoon and the dominance of macroalgae species that respond to nutrient enrichment. This implies that the Overall Eutrophic Condition Index of the Assessment of Estuarine Trophic Status model is a valuable tool for use as an eutrophication indicator based on the abundance of primary producers (macroalgae and phytoplankton). One source of uncertainty in the application of the model to this semi-arid coastal lagoon deals with estimating its susceptibility to eutrophication. The model showed that the lagoon is a highly sensitive ecosystem; however, significant factors are in place, such as an adequate water exchange, that reduce its susceptibility to eutrophication. In conclusion, the trophic status observed at Guaymas Bay is acceptable; however, an environmental management plan is necessary to prevent any adverse effects of eutrophication.

Laboratory experiments compared the removal efficiency of cells and toxins of the dinoflagellate Gymnodinium catenatum, using three concentrations of cells and three concentrations of red clay, montmorillonite, clinoptilolite, calcium oxide, calcium hydroxide, aluminium sulfate, chitosan, activated silica, and polyaluminium chloride, as coagulating or flocculating agents. Chitosan, calcium oxide, and calcium hydroxide were selected using the criterion of minimum concentration for maximum efficiency for removing cells. These were combined in pairs to measure their joint performance. In all cases, removal efficiency of cells was 95–99%. A combination of calcium oxide + chitosan effectively removed the cells, but failed to remove extracellular toxins produced by G. catenatum.

We examined the environmental and biological factors related to blooms of the toxic dinoflagellate Pyrodinium bahamense in three shallow, restricted subtropical lagoons in the Gulf of California during the rainy summer. In the San José, Yavaros, and El Colorado lagoons, the vegetative stage peaked at 63, 108, and 151 (×103 cells l-1), respectively. At San José, production of cysts peaked at 9.7×103 g-1 of dry sediment mass as the bloom declined. Large diatoms predominated, with P. bahamense the most common dinoflagellate during the blooms. Abundance of P. bahamense at San José was positively correlated with salinity (r=0.50, p=0.0003), seawater temperature (r=0.44, p=0.005), silicates (r=0.45, p=0.003), and ammonium (r=0.32, p=0.005), and negatively correlated with dissolved oxygen (r=-0.34, p

The morphology of Pyrodinium bahamense south of Isla San Jose in the Gulf of California, Mexico was described using light and scanning electron microscopy. Morphological and dimensional examination of whole cells and thecal patterns were conducted to discriminate between P. bahamense var. compressum and P. bahamense var. bahamense. Microscopic examinations confirmed that specimens of P. bahamense from Isla San Jose are closely related to P. bahamense var. bahamense. The main average dimensions were: cells 41.9 μm long, 43.8 μm wide, 55.6 μm amplitude, apical horn 7.2 μm long, and the left antapical spine 19.5 μm long. The highest cell concentration was 240 cells l−1 and occurred with a bloom of Pseudo-nitzschia spp. The presence of this dinoflagellate off the east coast of the Baja California Peninsula had not been previously reported. Recently, P. bahamense from Florida tested positive for saxitoxins. Paralytic shellfish poisoning from this species has occurred in Mexican waters. Here, significant aspects of taxonomy, toxicology, life cycle, and ecology are discussed.

In vitro experiments were performed with Gymnodinium catenatum Graham strains isolated from three locations in the Gulf of California to determine the variability in toxicity and toxin profiles. Strains were cultivated in GSe at 20° C ± 1° C, 150 μmol photons·m -2 ·s -1 (12:12 light:dark cycle), and harvested during different growth phases. Growth rates were higher than in previous studies, varying between 0.70 and 0.82 day -1 . The highest cell yields were reached at 16 and 19 days, with maximum densities between 1090 and 3393 cells· mL -1 . Bahia de La Paz (BAPAZ) and Bahia de Mazatlan (BAMAZ) were the most toxic (101 pg STXeq-cell 1 ), whereas strains from Bahia Concepcion (BACO) were the least toxic (13 pg STXeq·cell -1 ). A strain isolated from cyst germination was one of the least toxic strains. No significant changes in toxin content with culture age were observed (0.2 and 0.6pmol paralytic shellfish poisoning·cell -1 ). All strains contained neosaxitoxin (NEOSTX), decarbamoyl-saxitoxin (dcSTX), decarbamoyl-gonyautoxin-2,-3, (dcGTX2-3), N-sulfocarbamoylsaxitoxin (Bl), N-sulfo-carbamoylneosaxitoxin (B2), and N-sulfo-carbamoylgonyautoxin-2,-3 (C1-2). Bahia Concepcion strains had the highest content of Cl; BAPAZ and BAMAZ strains had a higher percentage of NEOSTX. Differences in toxin composition with culture age were observed only in BAMAZ and BAPAZ strains. Cultures with a higher percentage of long chains had more NEOSTX, while those with a higher proportion of short chains had a lower content of NEOSTX. Gulf of California strains are characterized by a high proportion of NEOSTX, and seem to have evolved particular physiological responses to their environment that are reflected in the toxin profile, suggesting different populations.

Laboratory studies were performed to determine the effect of temperature, salinity, seawater sources and culture media on the vegetative growth of clonal cultures of Gymnodinium catenatum isolated from Bahia Concepcion, Mexico. These isolates were heterothallic and isogamous. Exponential growth rates of G. catenatum in f/2 with different selenium concentrations and soil extract and GSe media were moderate. Maximum cell yields were obtained in GSe and f/2 media with selenium (10 � 8 and 10 � 7 M), while in f/2 medium with soil extract cell yields were considerably lower. The highest percentage of long chains was found in f/2 media supplied with selenium (10 � 8 M). The optimal temperature range for growth was 11.5-30 � C, with the highest growth rates between 21 and 29 � C. The range of salinity tolerated by G. catenatum changed with seawater source. With seawater from Vineyard Sound (Massachusetts, USA), G. catenatum grew at salinities from 15 to 36, with an optimal growth rate obtained at salinities between 26 and 30. With seawater from Bahia Concepcion, this species tolerated salinities from 25 to 40, with optimal growth at salinities between 28 and 38. Ecophysiological measurements reported here are consistent with the environ- ment of the bay, which has limited input of humic materials from runoff and high salinity and temperature. These data, when viewed with data from studies of globally distributed G. catenatum, demonstrate the ability of this species to live in a broad array of habitats.

The presence of ichthyotoxic phytoflagellates Chattonella marina, Fibrocapsa japonica, and Heterosigma akashiwo of the algal class Raphidophyceae are reported for first time in the Gulf of Mexico and the Pacific coast of Mexico. Phytoplankton were sampled to isolate and identify species, and to develop growth experiments in different media. We observed living material of the three species, but were unable to recognize specimens in preserved samples. Cultures were established by isolating single cells and diluting phytoplankton samples in modified f/2 and Erd–Schreiber media. Features, including morphological variations and pigment composition, of living cells under various nutrient conditions are described. These ichthyotoxic species produce harmful blooms in several parts of the world, although no documented cases have been reported in Mexico.

Strains of raphidophytes from different regions of the Gulf of California were established for identification and biochemical description. Raphidophyte in our coasts have been traditionally identified based on microscopic observations, a biochemical analyses of strains present in our coast is needed for a more detailed characterization and species confirmation. Strains were identified by morphological observations and sequencing of the 5.8S and COI regions. Cells were cultivated in modified f/2 media at 20°C with a light–dark cycle (12 h:12 h) and 150 μmol m−2 s−1 light intensity. Pigments were identified by HPLC, brevetoxins by LC–MS/MS, fatty acids by gas chromatography, superoxide radicals by spectrophotometry, and lipid peroxidation by the determination of thiobarbituric acid reactive substances. Strains were identified as Chattonella subsalsa, C. marina, and Fibrocapsa japonica. In all strains, the main pigment was chlorophyll a, followed by fucoxanthin, chlorophyll c1 and c2, violaxanthin, β-carotene, and diadinoxanthin. Strains were tested for PbTx-1, PbTx-2, PbTx-3, PbTx-6, PbTx-9, PbTx-carboxylic acid, brevenal, and brevisin; none were detected. All strains presented superoxide radical production and lipid peroxidation. The main fatty acids were 18:4 (n-3) and 20:5 (n-3). Strains had typical fatty acid composition for raphidophytes and produced brevetoxin-like compounds, had superoxide radical production, and lipid peroxidation. With this contribution, we confirm the presence of C. subsalsa, C. marina and F. japonica in the Gulf of California.

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.

Mediante ensayos de germinación se logró definir la relación quiste-teca de Gonyaulax spinifera (= Spiniferites mirabilis), Protoceratium globosum, Preperidinium meunieri (= Dubridinium caperatum), Protoperidinium denticulatum (= Brigantedinium irregulare) y Protoperidinium cf. thorianum. Los quistes se aislaron a partir del primer centímetro de sedimento superficial de muestras colectadas durante el periodo 2000-2002 en Bahía Concepción, Golfo de California. Los taxa identificados se ilustran con microfotografias, se describe la morfología de los estadios quístico y vegetativo, y también se incluye información sobre sinonimias, variación en talla y su distribución en México y en el mundo. Los ensayos de germinación permitieron describir por primera vez la relación quiste-teca de P. globosum, confirmar la presencia del estadio vegetativo de P. denticulatum en el Golfo de California y de la heterosporia en G. spinifera. También se establecieron con éxito cepas de G. spinifera y P. globosum.

The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahia 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.

We report the large subunit (LSU) rDNA sequences and morphology of several Gymnodinium catenatum dinoflagellate strains isolated from Bahia Concepcion, Mexico. PCR amplifications of the D1-D2 fragment of the nuclear LSU rDNA gene resulted in a single product of � 889 bp. A phylogenetic tree was constructed from the partial LSU rDNA (350 bp) sequences from six strains of G. catenatum isolated from the bay and 12 isolates from around the world. Strains from the bay grouped within the G. catenatum clade; however, a constant characteristic of G. catenatum strains from the bay is that, at position � 453, a single nucleotide polymorphism was observed, presenting cytosine instead of guanine. This single base polymorphism could indicate a mutation or genetic isolation from other G. catenum populations. It is suggested that the Western Pacific could be the ancestral population of this species. Significant differences were found between cell length (CL), cell width (CW) and CW/CL ratios in laboratory cultures in the late exponential growth phase. Average CL varied between 41 and 53.69 mm, with a range between 26.94 and 69.99 mm; average CW varied between 33.75 and 40.68 mm, with a range between 25.04 and 54.73 mm; the average CW/CL varied between 0.76 and 0.97 mm, with a range between 0.49 and 1.27 mm. Cingulum thickness was between 3 and 4.11 mm, with a range between 1.97 and 6.74 mm. Cell size varied with the length of the chain and position in the chain.

We studied seasonal prevalence of dinoflagellates and of cyst production in relation to hydrological factors in Baho´a Concepcion, Mexico. In situ production of dinoflagellate cysts was recorded for the first time in Mexico. The rest- ing stage of toxic Gymnodinium catenatum, potentially toxic Alexandrium pseudogonyaulax, and other red tide- forming dinoflagellates were collected in traps. Cyst associations were linked with the composition of vege- tative stages in the water column, and production yields (128 to 1.465=10 6 cysts m y 2 d y 1 ) were comparable with other reports in areas around the world. Seasonal abun- dance of major meroplankton dinoflagellates and rela- tionships with yields of newly-formed cysts coincides with hydrographic transitional periods in the water col- umn in spring and early fall. From factor analysis, the physico-chemical variables that correlate with the pres- ence of the major meroplanktonic species are, in descending order of importance: temperature, phos- phates, dissolved oxygen, silicate, nitrite, and nitrate. In Baho´a Concepcion, Gonyaulacales and Scrippsiella tro- choidea cysts are present during declines in algal blooms as a mechanism to counteract adverse conditions, and to secure an inoculum for blooming when favorable con- ditions return. In contrast, G. catenatum cysts maintain the motile stage over prolonged periods with recurrent germination.

La dinámica poblacional de dinoflagelados meroplanctónicos fue estudiada en Bahía Concepción, B.C.S., de 1999 al 2001. Se realizó un seguimiento y análisis de la distribución de quistes de dinoflagelados en sedimentos Holocénicos, su abundancia y composición taxonómica; así como de la relación existente entre factores hidrológicos y la presencia de dinoflagelados meroplanctónicos y los periodos de producción de sus quistes. La composición de los quistes en los sedimentos, estuvo integrada por Peridiniales calcáreos, Peridiniales orgánicos y Gymnodiniales; identificándose a nivel de especie un total de 25 morfotipos. Los quistes vacíos constituyeron el 75-90% con la dominancia de los Peridiniales calcáreos (30-70%) y Gonyaulacales (13-44%), representados principalmente por Scrippsiella trochoidea y Lingulodinium polyedrum. También es de particular importancia el hallazgo del quiste del dinoflagelado tóxico Gymnodinium catenatum y los primeros registros para el Golfo de California de Alexandrium margalefii, Protoperidinium americanum, P. denticulatum y P. latissimum, lo que permite ampliar su rango de distribución hacia zonas sub-tropicales del Pacifico Mexicano, particularmente el área del Golfo de California. En el primer centímetro de sedimento, la abundancia varió entre 173 y 9, 933 quistes g-1 (peso húmedo) y se observó que ésta se incrementa hacia el interior de la bahía. El patrón de distribución y abundancia de los quistes sugiere que la bahía actúa como una trampa y que su composición refleja una comunidad que se desarrolla localmente. A través de ensayos de germinación fue posible establecer la relación quiste-teca de: Alexandrium margalefii y Protoperidinium denticulatum; así como el establecimiento de los cultivos de A. margalefii, Gonyaulax digitale, Gonyaulax spinifera, Gymnodinium catenatum, Lingulodinium polyedrum, Protoceratium sp., Protoperidinium denticulatum y Scrippsiella trochoidea. La producción in situ de quistes de dinoflagelados fue registrada por primera vez en México. El estadio de reposo del dinoflagelado tóxico G. catenatum y del potencialmente tóxico Alexandrium pseudogonyaulax, así como de otras especies formadoras de marea roja fueron encontrados en trampas. La composición de los quistes recién formados fue comparable a la del estadio móvil en la columna de agua. La tasa de incorporación de quistes fue comparable a la reportada en diferentes ambientes costeros del mundo [...] The population dynamics of meroplanktonic dinoflagellates, with a special emphasis on their resting cysts, was studied in Bahía Concepción, Baja California Sur, Mexico, in 1999-2001. Monitoring and analysis of dinoflagellate cyst distribution in Holocene sediments, their abundance and taxonomic composition, seasonality of dinoflagellates and cyst production periods related to hydrological factors were considered. Cyst composition in sediments included the calcareous and organic Peridiniales, Gonyaulacales, and Gymnodiniales, with 25 morphotypes identified at species level. Empty thecae constituted 75-90% of cyst assemblages dominated by the calcareous Peridiniales (30-70%) and Gonyaulacales (13-44%), represented mainly by Scrippsiella trochoidea and Lingulodinium polyedrum. Of particular note is the occurrence of cysts of the toxic dinoflagellate Gymnodinium catenatum, as well as the first records of Alexandrium margalefii, Protoperidinium americanum, P. denticulatum and P. latissimum in the Gulf of California. These occurrences extend their geographic distribution to the subtropical Mexican Pacific, mainly in the Gulf of California. In the uppermost centimeter of sediment, counts varied from 173 to 9,933 cysts g-1 of wet weight, and increased in abundance in the inner area of the bay. Cyst abundance and distribution patterns suggest that the bay acts as a cyst trap, and that cyst assemblages reflect the local community of meroplanktonic dinoflagellates. With cyst germination assays, it was possible to register Alexandrium margalefii and Protoperidinium denticulatum for the first time in the Gulf of California and to establish cultures of Alexandrium margalefii, Gonyaulax digitale, G. spinifera, Gymnodinium catenatum, Lingulodinium polyedrum, Protoceratium sp., Protoperidinium denticulatum, and Scrippsiella trochoidea. In situ production of dinoflagellate cysts was recorded for the first time in Mexico. The resting stages of toxic Gymnodinium catenatum and potentially toxic Alexandrium pseudogonyaulax, as well as other red tide-forming dinoflagellates, were collected in cyst traps. Cyst assemblages were linked with the composition of vegetative stages in the water column. Production yields were found to be comparable with those in other areas worldwide.

The composition, abundance, and distribution of dinoflagellate resting cysts in recent sediments were analyzed at 12 sites in Bahia ConcepciOn in the subtropical Gulf of California. Calcareous and organic Peridiniales, Gonyaulacales, and Gymnodiniales were identified at species level (25 cyst types). Empty cysts constituted 75-90% of cysts in the samples. Cyst assemblages were dominated by calcareous Peridiniales (30-70%) and Gonyaulacales (13-44%), represented mainly by Scrippsiella trochoidea and Lingulodinium polyedrum. In the first centimeter of sediment, cyst counts varied from 173 to 9, 933 cysts g - 1 wet weight, and increased in abundance in the inner area of the bay. Cysts of the toxic species Gymnodinium catenatum were also detected, and successful cyst germination of Alexandrium margalefii is described. Cyst abundance and distribution patterns suggest that the bay acts as a cyst trap, and that the cyst assemblages reflect the local community of meroplanktonic dinoflagellates.

"El aporte excesivo de nutrientes de origen antropogénico hacia cuerpos de agua costeros genera procesos de eutrofización con efectos adversos al ambiente y a las actividades productivas. El objetivo de este estudio fue detectar síntomas de eutrofización y comparar la sensibilidad de índices ambientales en lagunas costeras semiáridas subtropicales del Estado de Sonora, México. La investigación se realizó en una laguna prístina, El Soldado, y tres lagunas receptoras de diferentes tipos y magnitudes de aguas residuales: Guaymas (receptora de aguas residuales urbanas), Lobos (receptora de aguas residuales agrícolas y urbanas), El Tóbari (receptora de aguas residuales agrícolas, camaronícolas y urbanas). La detección de eutrofización se realizó con el modelo de Evaluación del Estado Trófico Estuarino (ASSETS), y los índices: Índice de Estado Trófico (TRIX), Índice de Calidad Ambiental Costera (ICAC), e Índice Canadiense de Calidad del Agua (CCME-WQI). Los resultados del modelo ASSETS, aplicado a lagunas receptoras de aguas residuales, mostraron que su condición ambiental general fue: Guaymas buena; Lobos buena; y El Tóbari moderada. Sin embargo, mediante el ASSESTS, también se observó que tanto en El Tóbari, como en Lobos y Guaymas se pueden desarrollar eventos de hipoxia, y que son hábitats que propician la presencia de especies de macroalgas indicadoras de enriquecimiento por nutrientes y proliferaciones algales potencialmente nocivas. Los índices TRIX e ICAC mostraron que Guaymas fue mesotrófica y con buena calidad del agua; Lobos fue oligotrófica y con buena calidad del agua; El Tóbari fue mesotrófica y con tendencia a la mala calidad del agua; mientras que El Soldado fue oligotrófica y con buena calidad del agua. Ambos índices fueron sensibles para detectar la calidad ambiental y los efectos adversos, espaciales y temporales, del vertimiento de aguas residuales. El hecho de que las lagunas impactadas presentaran condición ambiental buena o moderada, se atribuye a que sus tasas de renovación del agua fueron < 16 días, y esto disminuye su susceptibilidad a la eutrofización. Los resultados del índice CCME-WQI mostraron que todas las lagunas presentan calidad de agua pobre; empero, existe incertidumbre asociada a los valores de referencia disponibles. En resumen, la detección de síntomas de eutrofización resultó más efectiva mediante el uso combinado de métodos (ASSETS, TRIX e ICAC)..." "The excessive input of nutrients from anthropogenic origin toward coastal water bodies generate eutrophication processes with adverse effects to the environment and productive activities. The objective of this study was to detect eutrophication symptoms and to compare the sensitivity of environmental indexes in semi-arid subtropical coastal lagoons of Sonora State, Mexico. The research was conducted in a pristine lagoon, El Soldado, and three lagoons that receive different types and magnitudes of wastewater: Guaymas (recipient of urban wastewater), Lobos (recipient of agricultural and urban wastewater), El Tóbari (recipient of agricultural, aquacultural, and urban wastewater). Eutrophication detection was performed with the ASSesment of Estuarine Trophic Status model (ASSETS) and the indexes: TRophic Index (TRIX), Arid Zone Coastal water quality Index (AZCI) and Canadian Water Quality Index (CCME-WQI). The results of the ASSETS model, applied to the wastewater leaden lagoons, showed that its overall environmental condition was: Guaymas good; Lobos good; and El Tóbari moderate. However, through ASSETS, it was also noted that El Tóbari, Lobos and Guaymas all have the capability to develop hypoxia events, and are habitats that promote the presence of indicators of nutrient enrichment macroalgae species, and potentially harmful algae blooms. TRIX and ICAC indexes showed that Guaymas was mesotrophic and with good water quality; Lobos was oligotrophic and with good water quality; El Tóbari was mesotrophic and with a poor water quality trend; while El Soldado was oligotrophic and with good water quality. Both indexes were sensitive to detect environmental quality and adverse effects, spatial and temporal, of the discarding of wastewaters. The fact that the impacted lagoons presented a moderate or good environmental condition is attributable to their water renewal rates of < 16 days, and this reduces susceptibility to eutrophication. The results of the CCME-WQI index showed that all lagoons have poor water quality; however, there is uncertainty associated with the available reference values. In summary, the detection of eutrophication symptoms was most effective through the combined use of methods (ASSETS, TRIX and AZCI)..."

"La escasez de información sobre taxonomía del grupo de los dinoflagelados en México ha evidenciado la necesidad de realizar estudios que involucren la descripción de los principales estadios del ciclo de vida de estos organismos. La presente investigación se abocó a describir la composición taxonómica de los dinoflagelados Peridiniales meroplanctónicos de Bahía Concepción en el Golfo de California a través del establecimiento de la relación quiste-teca. A partir de muestras de sedimento superficial se aislaron quistes Peridiniales calcáreos y orgánicos. El seguimiento del proceso de germinación de los quistes aislados, las características morfológicas de los quistes antes y después de la germinación, así como la confirmación de la presencia de la célula vegetativa, se registro mediante secuencias fotográficas. La composición de quistes estuvo integrada por especies pertenecientes a los géneros Diplopsalis, Pentapharsodinium, Peridinium, Preperidinium, Protoperidinium y Scrippsiella. Los quistes mas abundantes y de los que se obtuvo mayor éxito de germinación fueron del grupo de Peridiniales calcáreos, particularmente de Scrippsiella trochoidea. Se registró por primera vez en Bahía Concepción la presencia de los quistes de Protoperidinium cf. thorianum, Peridinium cf. stellatum, así como otros morfotipos de Protoperidinium. Se logró el primer registro para el Pacífico mexicano del género Pentapharsodinium. Se encontró heterosporia en Preperidinium meunierii, Protoperidinium claudicans, P. oblongum, P. leonis y P. subinerme. Los resultados obtenidos confirman que la diversidad de dinoflagelados Peridiniales de Bahía Concepción es mayor a la reportada hasta la fecha." "The scarcity of information on taxonomy of dinoflagellates in Mexico has demonstrated the necessity to perform studies that involve the description of the main stages in the life cycle of these organisms. This investigation described the taxonomic composition of the meroplanktonic Peridiniales of Bahía Concepción in the Gulf of California by the establishment of the cysts-theca relationships. From samples of superficial marine sediment, calcareous and organic cysts were isolated. The monitoring of the germination process, the morphologic characteristics of the cyst before and after germination, as well as the confirmation of the motile stage presence was documented with a photography sequence. The cyst assemblages were composed by the species of the genera Diplopsalis, Pentapharsodinium, Peridinium, Preperidinium, Protoperidinium and Scrippsiella. Cysts of the calcareous Peridiniales, in particular those of Scrippsiella trochoidea, were the most abundant and most easily germinated. Protoperidinium cf. thorianum, Peridinium cf. stellatum and some unidentified Protoperidinium species are first reported from Bahía Concepción. The genus Pentapharsodinium is first recorded in the Mexican Pacific. Heterospory was observed in Preperidinium meunierii, Protoperidinium claudicans, P. oblongum, P. leonis and P. subinerme. The results of the present study confirm that the diversity of dinoflagellates in Bahía Concepción is higher than that previously reported."