Search

On 19–20 August 2014, a moderate proliferation of dinoflagellates was detected in the southwestern part of Bahia de La Paz. The phytoplankton community within this red tide was composed of 60 microalgae taxa and was characterized by the presence of unarmored dinoflagellates such as Levanderina fissa and Polykrikos hartmannii . The proliferation occurred during low tide after a period of windy and rainy days. Densities of L. fissa varied from 163 to 265 × 10 3 cells L –1 and for P. hartmannii varied from 16 to 33 × 10 3 cells L –1 . Low densities were estimated on September and October samplings. Both species showed a great variation both in size and form. As part of the phytoplankton species composition during this proliferation, two taxa of dinoflagellates are new records for the Pacific coast of Mexico ( Ankistrodinium semilunatum and Sclerodinium calyptroglyphe ), one in the Gulf of California ( Pronoctiluca acuta ), and one in the Bahia de La Paz ( Prorocentrum robustum ). Cyanobacteria were an important group observed during this proliferation. The symbiotic association between a cyanobacterium Synechococcus sp., the stramenopile protist Solenicola setigera , and the diatom Leptocylindrus mediterraneus was observed for the first time in this bay. Proliferacion de Levanderina fissa y Polykrikos hartmannii (Dinophyceae: Gymnodiniales) en Bahia de La Paz, Golfo de California, Mexico Se detecto una proliferacion moderada de dinoflagelados en la porcion suroeste de la Bahia de La Paz del 19 al 20 de agosto de 2014. La comunidad del fitoplancton dentro de este florecimiento estuvo compuesta de 60 taxa y se caracterizo por la dominancia de Levanderina fissa y Polykrikos hartmannii . La proliferacion ocurrio durante la marea baja y despues de dias lluviosos. La abundancia de L. fissa vario de 163 a 265 × 10 3 cels L –1 y P. hartmannii vario de 16 a 33 × 10 3 cels L –1 . Densidades bajas fueron estimadas durante los muestreos de septiembre y octubre. Ambas especies mostraron una gran variacion en su forma y su tamano celular. Como resultado de la composicion especifica del fitoplancton encontrado durante esta proliferacion, dos taxa de dinoflagelados fueron nuevos registros para la costa Pacifica de Mexico ( Ankistrodinium semilunatum y Sclerodinium calyptroglyphe ), un taxon para el Golfo de California ( Pronoctiluca acuta ) y un taxon para la Bahia de La Paz ( Prorocentrum robustum ). Las cianobacterias fueron un grupo importante durante esta proliferacion. La asociacion simbiotica entre una cianobacteria Synechococcus sp., el protista stramenopiles Solenicola setigera y la diatomea Leptocylindrus mediterraneus se observo por primera vez en la bahia.

The coccolithophorid Scyphosphaera apsteinii is here reported for the first time from waters off the west coast of the Baja California Peninsula. Scypho­sphaera apsteinii is the type species of the genus Scyphosphaera and had hitherto been recorded only in the Atlantic and Indian Oceans, the Gulf of Mexico, the Mediterranean, and the Caribbean Seas. Specimens were found in samples collected in nets off Isla de Guadalupe in January 2013. This recording thus extends the geographical distribution of S. apsteinii from the Central Pacific (Hawaii) to the Eastern Pacific (NW Mexico).

The gymnodinioid marine dinoflagellates Torodinium robustum and T. teredo are reported for the Gulf of California. This is the first record of Torodinium teredo on the Pacific coast of Mexico. Both species were found mainly during the winter-spring in seawater at 19–27.5 °C. Torodinium robustum was the most frequent species. Morphological features of T. robustum and T. teredo varied widely and specimens observed in live samples and fixed in Lugol's solution were easily recognizable. Short description and microphotographs were provided for each species.

From mid-August to mid-September 1998, a dinoflagellate bloom in a shrimp pond near La Paz, Baja California Sur, was studied. Daily samples were taken of phytoplankton, dissolved oxygen, nutrient concentrations, photosynthetic pigments and proteins. The bloom occurred at temperatures of 29.7 to 33.2 °C. High densities of a Scrippsiella-like dinoflagellate (15.9 × 106 cells/L) occurred on the first day of sampling, reaching a peak of 249 × 106 cells/L on Day 13, and declining to 4 to 7 × 106 cells/L by Day 26. Chlorophyll a varied from 8.63 mg/m3 on Day 4 to 141.38 mg/m3 on Day 13. Total nitrogen varied widely (0.2–11.50 μM) while phosphates peaked only once on Day 13 (4.14 μM). Proteins ranged from 523 to 6387 μg/L; the latter value occurred two days after the maximal peak of nitrates and coinciding with the highest level of phosphates. Fertilizers added to the ponds increased nutrient concentration and stimulated phytoplankton growth. In turn, the food supply to cultured shrimp noticeably increased throu...

Se presentan los cambios en la distribucion espacial de la comunidad fitoplanctonica en Bahia Concepcion, B.C.S. de 1991 a 1993. Se estimo la abundancia total, la variacion espacio-temporal por fracciones de tamano (nano y microfitoplancton) y se describe su estructura. Se determinaron 235 taxa, en donde las diatomeas fueron el grupo con mayor riqueza de especies (131). Los generos mas importantes fueron Chaetoceros, Rhizosolenia y Nitzschia . El segundo grupo en importancia fue el de los dinoflagelados (92 especies), representados principalmente por Protoperidinium, Ceratium y Prorocentrum ; el tercer grupo fueron los silicoflagelados (9 especies), principalmente del genero Dictyocha . Las diatomeas dominaron en la temporada fria cuando la columna de agua se mantiene homogenea, en tanto que los dinoflagelados prosperaron durante la temporada calida cuando la columna de agua estuvo estratificada. De este ultimo grupo, 10 especies son toxicas o potencialmente toxicas. La abundancia fitoplanctonica total no mostro un comportamiento estacional definido, sin embargo, las variaciones interanuales mostraron un decremento de aproximadamente 25% durante 1992 y 1993, asociado con anomalias positivas de temperatura. A pesar de que las abundancias totales disminuyeron, la contribucion porcentual de la fraccion nanofitoplanctonica se mantuvo. Ecological indicators of the phytoplankton community structure in Bahia Concepcion, Gulf of California, Mexico Seasonal changes in the spatial distribution of the phytoplankton community were determined in Bahia Concepcion, B.C.S., from 1991 to 1993. The total abundance and the seasonal variations of phytoplankton size fractions (nanno and microphytoplankton) as well as its structure were determined. A total of 235 taxa were identified. Diatoms were the best represented group due to their high species richness (131). The most important genera were Chaetoceros, Rhizosolenia and Nitzschia . The second important group were dinoflagellates (92 species), represented mainly by Protoperidinium, Ceratium and Prorocentrum . The third numerically important group were the silicoflagellates (9 species). The most representative genus of this group was Dictyocha . A major presence of the diatoms was observed during the cold months with a homogeneous water-column. Major presence of dinoflagellates was recorded during the warm season when the water-column appeared stratified. Ten species of dinoflagellates were considered as toxic or potentially toxic. Total phytoplankton abundance did not show a clear seasonal pattern; nevertheless, the interannual variations exhibited an important decline of about 25 % during 1992 and 1993. These changes were related to positive anomalies of temperature. Altough phytoplankton abundance diminished, the percentage contribution of nannophytoplankton was stable.

Dinoflagelados en estanques de cultivo de camaron bajo condiciones tipicas de produccion Durante el cultivo del camaron se busca que las diatomeas sean el fitoplancton preponderante; sin embargo, frecuentemente surgen florecimientos algales nocivos, v.gr., de dinoflagelados. Nuestro objetivo fue identificar los taxa de dinoflagelados presentes y aquellos potencialmente nocivos bajo condiciones tipicas de produccion en una granja camaronera. Para ello se tomaron muestras mensuales (junio-octubre de 2003) de fondo (microfitobentos) y de superficie (arrastres). Se identificaron 46 taxa de dinoflagelados; los mas frecuentes fueron Protoperidinium cf. pacificum, Scrippsiella trochoidea, Prorocentrum minimum , taxa formadores de florecimientos nocivos; asimismo, se identificaron taxa potencialmente toxicos ( Prorocentrum rhathymum, P. micans, Dinophysis caudata, D. tripos ). En ningun caso hubo problemas en los estanques. Los dinoflagelados fueron menos abundantes al final del ciclo de cultivo del camaron.

This review presents a detailed analysis of the state of knowledge of studies done in Mexico related to the dinoflagellate Gymnodinium catenatum, a paralytic toxin producer. This species was first reported in the Gulf of California in 1939; since then most studies in Mexico have focused on local blooms and seasonal variations. G. catenatum is most abundant during March and April, usually associated with water temperatures between 18 and 25 ºC and an increase in nutrients. In vitro studies of G. catenatum strains from different bays along the Pacific coast of Mexico show that this species can grow in wide ranges of salinities, temperatures, and N:P ratios. Latitudinal differences are observed in the toxicity and toxin profile, but the presence of dcSTX, dcGTX2-3, C1, and C2 are usual components. A common characteristic of the toxin profile found in shellfish, when G. catenatum is present in the coastal environment, is the detection of dcGTX2-3, dcSTX, C1, and C2. Few bioassay studies have reported effects in mollusks and lethal effects in mice, and shrimp; however no adverse effects have been observed in the copepod Acartia clausi. Interestingly, genetic sequencing of D1-D2 LSU rDNA revealed that it differs only in one base pair, compared with strains from other regions.

Blooms of the ciliate Myrionecta rubra are quite common in Bahia de La Paz. In June and July 2005 two blooms of this species were sampled to determine abundance, plankton biomass, nutrients, dissolved oxygen, and temperature. During the bloom in June, surface temperature ranged from 19.0 °C to 19.6 °C and dissolved oxygen from 4.2 mg l -1 to 4.7 mg l -1 . During the second bloom, surface temperature as 24.2 °C and dissolved oxygen was 6.7 mg l -1 . At 25 m depth, conditions were 20.0 °C and 3.5 mg l -1 , respectively. At the surface, nutrients were low, except for ammonium (1.14 µM – 2.27 µM). High densities of M. rubra (2.14 × 106 cells l -1 ), chlorophyll a (55.6 µg l -1 ), chlorophyll c (6.0 µg l -1 ), and alloxanthin (8.1 µg l -1 ) were recorded. This last pigment is characteristic of the cryptophyte group, suggesting an association of the ciliate with this algal group. Winds from the southeast varied from 3 to 4.5 m s -1 in June and 1.7 to 4.8 m s -1 in July. The presence of this bloom under low thermal stratification and with the highest density of the ciliates at the surface during the onset of the bloom suggest that southeastern winds mixed the shallow water column, brought up nutrients from the bottom sediments, and induced high concentrations of the cryptophytes. Proliferaciones de Myrionecta rubra en Bahia de La Paz, Golfo de California, al inicio del verano de 2005 Las proliferaciones del ciliado Myrionecta rubra son frecuentes en Bahia de la Paz. Durante junio y julio de 2005 se registraron dos proliferaciones de esta especie en tres sitios de esta bahia. Durante estos eventos se tomaron muestras para determinar abundancia, biomasa planctonica, nutrientes, oxigeno disuelto y temperatura. En junio, la temperatura oscilo entre 19.0 °C y 19.6 °C y el oxigeno entre 4.7 mg l -1 y 4.2 mg l -1 . En julio fue de 24.2 °C y 6.7 mg l -1 y disminuyo a 20.0 °C y 3.5 mg l -1 a 25 m de profundidad. Los nutrientes fueron bajos, siendo unicamente altos los de amonio en superficie (1.14-2.27 µM). Se presentaron valores altos de biomasa, expresada como clorofila a (55.6 µg l -1 ), clorofila c (6.0 µg l -1 ) y de aloxantina (8.1 µg l -1 ); este ultimo, es caracteristico de criptofitas asociadas con el ciliado M. rubra , el cual alcanzo densidades maximas de 2.14 x 106 celulas l -1 . Los vientos dominantes de junio fueron del sureste (3.0 m s -1 - 4.5 m s -1 ) y de 1.7 m s -1 - 4.8 m s -1 en julio. La debil estratificacion y la presencia en superficie de M. rubra durante la tarde, sugieren que los vientos del sureste promueven la mezcla de la columna de agua. Esto propicia la remocion de nutrientes de los sedimentos hacia la superficie, promoviendo el incremento de la abundancia de la criptofita.

A circadian rhythm of the dinoflagellate Peridinium quadridentatum was studied at a time-series station in the southwestern Gulf of Mexico, in May 2007. Different substrates (water column, the seagrass Thalassia testudinum, macroalgae, coral rubble and sandy sediment surface) were sampled at the site at 1.5-3.5m depth. In the samples of coral rubble, P. quadridentatum was scarce. In the water column, the species showed an abundance peak at 15:00. The cell abundance of P. quadridentatum in Thalassia samples increased from 15:00 until 18:00 (1.81×10(4)cells/gsubstratewet weight), and then continuously decreased until 06:00. Changes in P. quadridentatum cell abundance on macroalgae followed the same trend as on Thalassia, with the maximal value at 18:00. The higher abundance of P. quadridentatum (up to 1.40×10(4)cells/gSWW) in macroalgae samples showed the preference for seaweeds. P. quadridentatum has a neritic tropical-boreal distribution. A new combination is proposed: Peridinium quadridentatum var. trispiniferum.

Se presentan cuatro nuevos registros de dinoflagelados y el reporte de dos dinoflagelados desnudos planctonicos para la Bahia de La Paz y el Golfo de California. Los Brachidiniales Asterodinium gracile y Brachidinium sp. son nuevos registros para el Pacifico Mexicano y Brachidinium capitatum es nuevo registro para el Golfo de California. Se conoce poco acerca de la distribucion y morfologia de estas especies ya que son raras y se han reportado en pocas ocasiones. A. gracile y Kofoidinium pavillardii son consideradas especies de la flora de sombra. En este trabajo se documentaron fotograficamente todas las especies. New records of naked dinoflagellates from the Gulf of California, Mexico Four new records of naked planktonic dinoflagellate and two rare taxa were found in Bahia de La Paz, Gulf of California. The Brachidiniales Asterodinium gracile and Brachidinium sp. are new records for the Mexican Pacific and Brachidinium capitatum is a new record for the Gulf of California. Little is known about the distribution and morphology of these species since they are rare and have been scarcely reported in the worldwide literature. A. gracile and Kofoidinium pavillardii are considered as members of the shade flora. All species are photographically documented.

Benthic/epiphytic dinoflagellates were monitored every 2 wk from May to December 2005 in the Veracruz reef zone, Gulf of Mexico. This assemblage was characterized by low species diversity (at least 17 species from 11 genera) and high abundance: Amphidinium cf. carterae (41 172 cells g -1 substrate wet weight), Prorocentrum lima (29 756 cells g -1 ), Coolia monotis (2724 cells g -1 ), Ostreopsis heptagona (1202 cells g -1 ); P. lima was the dominant species. Clear sea- sonal population dynamics occurred, with the highest abundance in May-June, and the dynamics differed at 2 neighbouring sampling sites. In August to December dinoflagellate abundance de- creased considerably. Most of the epiphytic dinoflagellates did not show any significant preference for a macrophyte substrate (23 macroalgal and 2 seagrass species) or for any species or major algal group, although the seagrass Thalassia testudinum appeared to be the most abundant and perma- nent host species. The highest abundance of P. lima occurred on the chlorophyte Ulva fasciata (30 879 cells g -1 ) and T. testudinum (31 467). Dinoflagellates were usually scarce on dead coral (Acro- pora sp. and Millepora alcicornis) fragments (0 to 5039 cells g -1 ) and surface bottom sediments (2 to 84), and were slightly more abundant on living Diploria strigosa (329 to 1830) and more numerous in a fringing reef zone compared to a reef lagoon near an offshore island. Dinoflagellate abundance was not correlated with any measured physical or chemical parameter (temperature, salinity, pH, dis- solved oxygen, nitrates, nitrites, ammonium, phosphates, precipitation or wind speed and direction). There is a high potential for outbreaks of ciguatera in the studied area.

Gymnodinium catenatum Graham is a paralytic shellfish poison (PSP) producer that was described for the first time from the Gulf of California in 1943. During the last decade, its distribution along the Mexican Pacific coastline has increased. In Bahia Concepcion, a coastal lagoon on the western side of the Gulf of California, G. catenatum has been linked to significant PSP concentrations found in mollusks. In this study, we describe the saxitoxin profile of 16 strains of G. catenatum , and catarina scallops ( Argopecten ventricosus ) from Bahia Concepcion. Toxins were analyzed by HPLC with post-column oxidation and fluorescence detection. The average toxicity of the G. catenatum strains was 26.0±6.0 pg and 28.0±18.0 pg STX eq/cell after 17 and 22 days of growth, respectively. Ten toxins were recorded, but only dcSTX, dcGTX2, dcGTX3, C1, and C2 were always present in all strains at both growth stages. Since toxin profiles in scallops were similar to the cultures, biotransformations are not significant in catarina scallop. NeoSTX, GTX2, GTX3, and B2 were present in some G. catenatum strains and their presence varied with the age of the culture. In scallop samples, dcSTX, dcGTX2, and dcGTX3 were the most abundant toxins, and from the C-toxin group, only C2 was found. This unique toxin profile can be used as a biomarker for this population, when compared with strains of G. catenatum from other geographic regions.

Samples of epiphytic diatom assemblages found on prop roots of red mangrove (Rhizophora mangle) from four sites were collected at two tidal levels of exposure on two different dates from the cool season (autumn, spring). The overall floristic analysis yielded 171 diatom taxa, including 16 new records for the Baja California peninsula. Diversity estimates were among the highest ever measured for benthic diatoms using Shannon's (mean H′ = 4.89) and Simpson's (0.945) indices. Many species scored high on the Biological Value Index (BVI), thus reflecting their numerical importance within the assemblages. According to diversity values and overall species composition, all sampling sites represented a similar habitat consisting of three types of substrates: prop roots, epiphytic macroalgae, and sediments. These values are considered to represent stability in the diatom assemblages living on red mangrove prop roots. Thus, the conditions determined by periodic tidal exposure are not to be considered extrem...

Parasitism within dinoflagellates is a widespread and well-documented phenomenon. Parasitic dinoflagellates of the genus Amoebophrya commonly infect free-living toxic, and non-toxic dinoflagellates species which may cause harmful red tides. Infections of Ceratium furca by A. ceratii were observed in red tides samples collected in the northwest coast of Baja California between 30°01'05'' N, 115°51'16'' W and 31°09'33'' N, 116°31'09'' W. This is the first record of this particular parasitic dinoflagellate in Mexican Pacific waters. There were mainly three dinoflagellate species causing this particular seawater discoloration: a Gymnodinium-like dinoflagellate, Ceratium furca, and Akashiwo sanguinea. These reached concentrations as high as 560 000, 762 600, and 395 400 cells L-1, respectively. During the bloom, surface water temperature ranged between 13 and 17°C. Seawater salinity ranged from 33.2 to 33.8 psu. About 1.5% of the individuals of C. furca observed were infected by the intracellular parasite dinoflagellate Amoebophrya ceratii. This parasite was observed mainly inside specimens of Ceratium furca and very few specimens of Ceratium macroceros. In general, individuals of C. furca were partially or totally deformed. Infections by A. ceratii could delay or inhibit the dinoflagellate blooms as infected dinoflagellates become reproductively incompetent.

A bloom of the diatom Rhizosolenia debyana H. Peragallo was observed in the southwestern Gulf of California. This bloom was estimated to be about 22 km long and represents the first record of this species for the area. Total abundance of R. debyana ranged from 2,576,000 to 3,684,000 cells liter-1. Chlorophyll a concentrations ranged from 17.15 to 41.45 mg/m3. Rhizosolenia debyana has a tropical and subtropical distribution.

"A moderate bloom of Pseudo-nitzschia species occurred during collection of phytoplankton in Estero Santa Cruz, the State of Sonora, Mexico, in August 2012. The abundance of Pseudo-nitzschia in 2 samples was 84x103 and 160x106 cells L –1. Results show the presence of 2 species, P. brasiliana and P. cf. pseudodelicatissima, which were responsible for a microalgae bloom. This is the first proliferation of P. brasiliana in the Gulf of California. P. cf. pseudodelicatissima was present in higher densities. A short morphological description is provided, including data from scanning electronic microscopy."

A mass stranding of several species of teleostean fish occurred on the south-eastern beaches of Los Cabos on Mexicos Baja California peninsula between 16 and 21 June 2011. At least 22 species belonging to 17 families, an estimated 50 t, were stranded along 43.5 km of beach from 9 km north-west of the Cabo San Lucas harbour (22°54′ 54.06″N–109°50′ 07.45″W) to Playa San Luis (23°10′41.78″N–109°28′39.49″W). Stranding of fish was attributed to a bloom of the photosynthetic planktonic ciliate Myrionecta rubra by local health authorities; however the information derived from necropsies was not available to the authors, so other causes cannot be excluded.

"The naked marine dinoflagellates Proterythropsis vigilans, Nematodinium armatum, and Nematodinium torpedo are reported for the first time in the Gulf of California. The first and the third species are also recorded for the first time on the Pacific coast of Mexico. They were recorded during winter-spring in seawater at 20-26.5°C. Nematodinium armatum was the most frequent species. Proterythropsis vigilans was less frequent. The 3 species were found in phytoplankton net samples. No quantitative data are reported here. A short description is given for each species, and micrographs provide information about the main morphological characteristics."

Red tide patches were observed in Bahia de La Paz in June 17 and 18 of 2008. According to temperature and wind data this bloom occurred under upwelling-like conditions. Examination of the red tide samples showed the ciliate Myrionecta rubra and the naked dinoflagellates Gyrodinium instriatum and Katodinium glaucum as the main species responsible for this bloom. Total density (microalgae and ciliate) at the sampling stations was similar on both days, varying from 4607 × 10 3 cells L -1 to 4976 × 10 3 cells L -1 on the first day, and from 4172 × 10 3 cells L -1 to 5024 × 10 3 cells L -1 on the second day. Phytoplankton biomass (chlorophyll a ) observed during the first day of the bloom was 1.5 mg m -3 . Dinoflagellates and diatoms were the most numerically important phytoplankton groups. The phytoplankton community showed a high species richness, particularly heterotrophic dinoflagellates and ebridians. The ecological importance of the heterotrophic component of naked dinoflagellates and the ebriids for this bay is discussed. Florecimiento multiespecifico de microalgas en la Bahia de La Paz, Golfo de California, Mexico (Junio, 2008) Durante los dias 17 y 18 de junio de 2008, se observo una marea roja en la Bahia de La Paz. De acuerdo con los datos de temperatura y de vientos, este florecimiento ocurrio bajo condiciones muy similares a las de una surgencia. El examen de las muestras de marea roja revelaron que el ciliado Myrionecta rubra y los dinoflagelados desnudos Gyrodinium instriatum y Katodinium glaucum fueron las principales especies responsables de esta proliferacion. La densidad total (microalgas y ciliado) fue similar en ambos dias, variando de 4607 × 10 3 cels L -1 a 4976 × 10 3 cels L -1 durante el primero y entre 4172 × 10 3 cels L -1 y 5024 × 10 3 cels L -1 el segundo dia, respectivamente. La biomasa fitoplanctonica (clorofila a ) medida durante el primer dia del florecimiento fue de 1.5 mg m 3 . Los dinoflagelados y las diatomeas fueron los dos grupos del fitoplancton numericamente mas importantes. Se observo una comunidad fitoplanctonica con una alta riqueza de especies, particularmente de dinoflagelados y ebriidos heterotroficos. Se discute la importancia del componente heterotrofico de los dinoflagelados desnudos y ebriidos.

Plankton samples collected from Bahia de La Paz, Baja California Sur, Mexico in June 2008 revealed infection of copepods by Blastodinium spp. Of eight copepod genera encountered in the samples, only one ( Paracalanus ) was parasitized by Blastodinium . Infection prevalence was low, 0.6 % to 2.0 %, with all parasitized individuals being females tentatively identified as Paracalanus parvus . All but one infected host examined during the study was parasitized by Blastodinium crassum , the sole exception being a Paracalanus cf. parvus infected by Blastodinium contortum. A phylogeny constructed using a dataset of ~1.3 Kb sequences of the small subunit ribosomal DNA gene of B. contortum and B. crassum from Bahia de La Paz and 36 other dinoflagellate sequences available in GenBank, including all available for Blastodinium , placed Blastodinium as a monophyletic clade deep within the Dinokaryota. Sequence divergence among B. contortum ex Paracalanus cf. parvus from Bahia de La Paz, B. contortum ex P. parvus from the Mediterranean Sea, B. contortum ex Clausocalanus arcuicornis , B. crassum ex P. cf. parvus from Bahia de La Paz, and B. navicula ex Corycaeus giesbrechti supported separation of the three parasites as distinct species. Prevalecencia y filogenia de dinoflagelados parasitos (genero Blastodinium ) que infectan copepodos en el Golfo de California Muestras de plancton recolectadas en junio de 2008 en la Bahia de La Paz, Mexico, revelaron la infeccion de copepodos por Blastodinium spp. De ocho generos de copepodos encontrados, solo Paracalanus estuvo parasitado por Blastodinium . El porcentaje de prevalecencia de infeccion fue bajo, de 0.6 % a 2.0 %. Todos los ejemplares parasitados fueron hembras, identificadas tentativamente como Paracalanus parvus . Los hospederos analizados durante este estudio, a excepcion de uno, estuvieron parasitados por Blastodinium crassum , siendo la unica excepcion Paracalanus cf. parvus , el cual fue infectado por Blastodinium contortum . Se construyo la filogenia usando la base de datos de secuencias ~1.3 Kb de pequenas subunidades de DNA ribosomal de los genes de B. contortum y B. crassum de La Bahia de La Paz, ademas de otras 36 secuencias disponibles en GenBank, incluyendo todo lo disponible de Blastodinium y colocando a Blastodinium como un grupo dentro de los Dinokaryota. La divergencia de las secuencias entre B. contortum ex Paracalanus cf. parvus de Bahia de La Paz, B. contortum ex P. parvus del Mar Mediterraneo, B. contortum ex Clausocalanus arcuicornis, B. crassum ex P. cf. parvus de Bahia de La Paz, y B. navicula ex Corycaeus giesbrechti respalda la separacion de los tres parasitos como especies diferentes.

Los florecimientos de microalgas son frecuentes y periódicos a lo largo de todo el año en La Ensenada de La Paz, una laguna formada por una barra de arena larga que se encuentra al extremo sur de la Bahía de La Paz, ubicada al suroeste del Golfo de California. En julio de 2003 se observaron parches de color café de Peridinium quinquecorne Abé en la playa cercana a la boca de esta laguna. P. quinquecorne es un dinoflagelado tecado, el cual es cosmopolita en aguas neríticas y estuarinas. Los parches presentaron 50 y 100 m de largo por 10-15 m de ancho y fueron observados durante dos días cuando la temperatura del agua era de 26.2 a 27 °C. Los parches de P. quinquecorne se detectaron cuatro días después de haber llovido. La abundancia de P. quinquecorne varió de 3.4 a 6.4 × 106 céls l-1, y la clorofila a lo hizo entre 13.20 y 17.75 mg m-3. Las concentraciones de nutrientes en esta área fueron más altas que las normales, lo cual puede deberse a la resuspensión de sedimentos causados por acción de la marea. El alto contenido de nutrientes promovió la formación de parches de P. quinquecorne en esta porción de la laguna.