ABSTRACT The marine phytoplankton community responds to latitudinal, longitudinal (coast to ocean), and vertical environmental gradients, an important subject in Oxygen minimum zones (OMZ). The phytoplankton structure and the effect of environmental gradients along the central Mexican Pacific, an area within an OMZ, were studied, especially the importance of size fractions and taxonomic groups. A combination of various methods and protocols, such as microscopic analysis, flow cytometer, and pigment analysis, were followed in this study. Oceanographic conditions included thermal gradients along the study area and unreported evidence of a weak upwelling in the southern zone (Acapulco). Vertical distribution of chlorophyll a showed subsurface maxima (SCM, 15-45 m depth) in all stations, and deeper chlorophyll-a maxima (DCM, 85-95 m depth) in more oceanic stations. Chain-forming diatoms dominated in the northern zone stations. Prochlorococcus, Synechococcus, and picoeukaryotes abundances ranged between 0.01 to 21.7 cells×104 mL−1, although most samples showed the highest contribution to biomass (47.95 µg C L−1) by picoeukaryotes. Expected tendencies of Prochlorococcus distribution were observed: highest densities coincided with the DCM and divinyl chlorophyll-a distribution at oceanic stations. Fucoxanthin had the highest concentrations, whereas fucoxanthin and zeaxanthin concentrations were higher at SCM depths. We documented the co-dominance of the pico- and microplankton: picoplankton was important at the DCM, related to oligotrophic and more stratified water column, whereas microplankton prevailed in coastal stations, with mixed water column, high nutrient concentrations, and diatoms as the dominant group. Picoeukaryotes abundances were related to the concentration of prasinoxanthin, which suggests an important mamiellophyte component not previously revealed.

ABSTRACT This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic composition in the surface waters of Todos Santos Bay, a semi-enclosed bay within the upwelling zone of the Baja California peninsula (México). Two methodological approaches (microscopy and chemotaxonomy [CHEMTAX]) were used to describe the variability of some genera and species (observed under the microscope) and the importance of those groups that cannot be observed microscopically. Phytoplankton biomarker pigments were measured with high-resolution liquid chromatography and used as input to run the CHEMTAX software to determine the contribution of the main phytoplankton groups to chlorophyll-a (Chl-a). The microscopic analyses showed that diatoms and dinoflagellates comprised 65 and 33% of the total cells, respectively. Dinoflagellates were most abundant in the inner bay and during cold months; the most frequent and abundant genera were Tripos, Protoperidinium, and Prorocentrum. Among diatoms, the most frequent genera were Cylindrotheca, Guinardia, Navicula, Pseudo-nitzschia, and Chaetoceros. CHEMTAX indicated that, together with diatoms, the flagellates prymnesiophytes and chlorophytes contributed a median of 80% to Chl-a, with chlorophytes as the most important group (29.9%). The high contribution of these flagellates suggests that they are represented by small-sized cells not visible by the light microscopy used. However, CHEMTAX largely underestimated the contribution of dinoflagellates (due to the presence of many mixotrophic species). Hence, our results emphasize the importance of using both techniques for a more detailed evaluation of the taxonomic composition of phytoplankton in this and other coastal regions.

Abstract Over the last decades, regional climate changes, erosion, and heightened agricultural runoffs have increased nutrient and particle input in rivers, unbalancing the biogeochemical cycle of this suspended material along estuaries. In this context, particle fluxes in the euphotic zone, a very productive layer and important to maintain the food chain and estuarine preservation, require better understanding. This study aims to evaluate particle sedimentation fluxes in the photic zone of the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC), considering sectors under different salinities and trophic statuses. A cylindrical sediment trap was installed at the base of the photic layer to measure particle fluxes and photopigments. Meanwhile, water samples were taken to measure temperature, salinity, pH, dissolved oxygen, and nutrients. Valo Grande (a freshwater domain) showed high nutrient concentrations, in which high fluxes of phaeopigments and chlorophyll-b highlighted the contribution of vegetable detritus to particle sinking. In the Batatais mangrove creek, the high fluxes of organic particles (675.32 mg m-2 d-1) and chlorophyll-a (98.40 mg m-2 d-1) evinced a high contribution of microplankton to carbon sinking. During the winter of 2018, flocculation processes were evinced in the flood tide of the Cananéia Bay as an important driver of sedimentation rates, with considerable fluxes of inorganic particles (1161.20 mg m-2 d-1) and chlorophyll-a (83.27 mg m-2 d-1). In the summer of 2019, we observed a lower flux in total particles (451.24 mg m-2 d-1) in a period of haline stratification. In the Ararapira Channel, the lowest organic particle fluxes (<100 mg m-2 d-1) were associated with ultra-oligotrophic conditions, indicating a low influence of microplankton on sinking particles. These findings suggest that freshwater input, tidal variation, and trophic status are relevant controls of sinking particles in different CIELC sectors. decades changes erosion rivers estuaries context preservation understanding CananéiaIguape Iguape EstuarineLagoon Estuarine Lagoon CIELC, , (CIELC) statuses photopigments Meanwhile temperature salinity pH oxygen nutrients domain concentrations chlorophyllb chlorophyll b creek 675.32 67532 675 32 (675.3 m2 m 2 m- d1 d 1 d-1 chlorophylla 98.40 9840 98 40 (98.4 2018 rates 1161.20 116120 1161 20 (1161.2 83.27 8327 83 27 (83.2 d1. . 2019 451.24 45124 451 24 (451.2 stratification Channel <100 100 (<10 ultraoligotrophic ultra oligotrophic conditions variation (CIELC 675.3 6753 67 3 (675. d- 98.4 984 9 4 (98. 201 1161.2 11612 116 (1161. 83.2 832 8 (83. 451.2 4512 45 (451. <10 10 (<1 675. 6 (675 98. (98 1161. 11 (1161 83. (83 451. (451 <1 (< (67 (9 (116 (8 (45 < ( (6 (11 (4 (1

Resumo O picophytoplankton marinho tornou-se uma questão importante para compreender a ecologia global das formas fototróficas, devido à sua ampla distribuição e contribuição para a biomassa e a produtividade. Estudamos os pigmentos de abundância, distribuição e assinatura do picofitoplâncton procarionte Prochlorococcus e Synechococcus durante um cruzeiro oceanográfico no Pacífico central mexicano, uma zona mínima de oxigênio relativamente poco conhecida (OMZ) e o efeito de três gradientes ambientais. As abundâncias de Prochlorococcus e Synechococcus foram comparáveis às encontradas em outras áreas tropicais (0.17 to 30.37 X 104 células mL-1, e 0.9 to 30.97 X 104 células mL-1, respectivamente). As abundâncias de Prochlorococcus atingiram o maior número em águas mais profundas, coincidindo frequentemente com a segunda intensidade de fluorescência in situ profunda (e clorofila a), em estações oceânicas, abaixo da nitratoclina, enquanto as abundâncias de Synechococcus foram maiores nas águas de subsuperficie e sua concentração máxima geralmente coincidiu com os máximos de subsuperficie de fluorescência in situ, com abundâncias ligeiramente mais altas nas estações costeiras. As análises estatísticas suportam significativamente esses resultados. A distribuição da divinil-clorofila a foi errática ao longo da coluna de água e coincidiu ocasionalmente com os máximos de fluorescência in situ profundos, enquanto que a distribuição da zeaxantina seguiu geralmente a da clorofila a e as abundâncias de Synechococcus e atingiu o pico. Estes resultados são semelhantes aos encontrados anteriormente na área de estudo e em zonas mais temperadas, e também à tendência geral na OMZ, mas confirmam que a clorofila profunda a maxima é atribuída a altas densidades de Prochlorococcus. Além disso, encontramos a abundância e distribuição de Prochlorococcus e Synechococcus fortemente conduzida pelos gradientes ambientais observados.

Abstract Marine picophytoplankton has become an important issue to understand the global ecology of phototrophic forms, due to its wide distribution and contribution to biomass and productivity. We studied the abundance, distribution and signature pigments of the prokaryote picophytoplankters Prochlorococcus and Synechococcus during an oceanographic cruise (26 April to 7 May, 2011) in the central Mexican Pacific, a relatively poorly-known oxygen minimum zone (OMZ), and the effect of three environmental gradients. Prochlorococcus and Synechococcus abundances were comparable with those found in other tropical areas (0.17 to 30.37 X 104 cells mL-1, and 0.9 to 30.97 X 104 cells mL-1, respectively). Prochlorococcus abundances reached highest numbers in deeper waters, often coinciding with the second deep in situ fluorescence (and chlorophyll α) maxima, at oceanic stations, below the nitratecline, whereas Synechococcus abundances were higher at subsurface waters and its concentration maxima usually coincided with the subsurface in situ fluorescence maxima, with slightly higher abundances in coastal stations. Statistical analyses support significantly these results. Distribution of divinyl-chlorophyll α was erratic along the water column and occasionally coincided with the deep in situ fluorescence maxima, whereas the distribution of zeaxanthin usually followed that of chlorophyll α and the abundances of Synechococcus, and peaked together. These results are similar to those previously found in the study area and in more temperate zones, and also to the general trend in OMZ, but confirm that the second deep chlorophyll α maxima are attributed to high Prochlorococcus densities. We additionally found the abundance and distribution of Prochlorococcus and Synechococcus strongly driven by the environmental gradients observed.

Evidence of the use of manganese oxides in the northernmost area of Chile has been dated as early as the Archaic Period (ca. 11,500-4,000 cal. BP). In the lowland coastal zone and valleys, this material is usually associated with the hunting, gathering and fishing Chinchorro groups that used this substance in the processes of artificial mummification as well as for naturally mummifies corpses. In the highlands, manganese oxide has been identified in rock shelters occupied by highland hunter-gatherer and used in rock art painting, attributed to this period. Additionally, the geology of the region indicates that manganese oxides would have come from the highlands. Given this set of information, and the results of the elemental analyses of pigments and paints from archaeological context, we discuss about the production or "chaîne opératoire" of black color from manganese ore, the cryptomelane. Also, different alternatives of procurement and mobility of manganese oxides developed by archaic societies from this region are proposed.

La utilización de óxidos de manganeso se evidencia en el extremo norte de Chile desde el periodo Arcaico (ca. 10.500-4.000 cal. a.p.) en tierras bajas (costa y valles) y tierras altas (precordillera y altiplano). En tierras bajas aparece en contextos de cazadores-recolectores y pescadores Chinchorro, en los procesos de momificación artificial y en cuerpos momificados de forma natural. En tierras altas se encuentra en aleros ocupados por cazadores-recolectores terrestres altoandinos. Adicionalmente, la información geológica existente apunta a que las fuentes de los óxidos de manganeso se encuentran sólo en sectores altoandinos. Con toda esta información, sumado a nuestros resultados obtenidos a partir de análisis físico-químicos de los pigmentos y pinturas de contextos arqueológicos se discute sobre la producción o cadena operativa del color negro a partir del mineral de manganeso, la criptomelana. Adicionalmente, se proponen alternativas interpretativas en torno al abastecimiento y movilidad de los óxidos de manganeso desarrollados por las sociedades arcaicas de la región.

OBJETIVO: A presente pesquisa visou avaliar a biomassa ficoperifítica em duas regiões submetidas a diferentes impactos antrópicos na lagoa Juara, ecossistema costeiro com múltiplos usos, a fim de testar a hipótese de que a região próxima ao lançamento de esgoto apresenta maior biomassa. MÉTODOS: Três estruturas experimentais contendo substratos artificiais (lâmina de vidro) foram implantadas em dez/2009 em duas estações amostrais: ED - próxima ao lançamento de efluentes domésticos; TR - na área de piscicultura intensiva (tanques-rede). Foram realizadas coletas, em cada estrutura experimental, após 21, 26 e 31 dias de colonização. Foram avaliadas: transparência, condutividade elétrica, pH, turbidez, sólidos totais em suspensão, alcalinidade, oxigênio dissolvido, temperatura da água, nitrogênio total, nitrato, nitrito, nitrogênio amoniacal, fósforo total, ortofosfato e silicato. Três estruturas experimentais contendo substratos artificiais (lâmina de vidro) foram implantadas em dez/2009 em duas estações amostrais: ED - próxima ao lançamento de efluentes domésticos; TR - na área de piscicultura intensiva (tanques-rede). Foram realizadas coletas, em cada estrutura experimental, após 21, 26 e 31 dias de colonização. Foram avaliadas: transparência, condutividade elétrica, pH, turbidez, sólidos totais em suspensão, alcalinidade, oxigênio dissolvido, temperatura da água, nitrogênio total, nitrato, nitrito, nitrogênio amoniacal, fósforo total, ortofosfato e silicato. O ficoperifiton foi analisado quanto à biomassa: biovolume (total e por classe); pigmentos (clorofila a e b e carotenóides) e feofitina; peso seco e peso seco livre de cinzas. RESULTADOS: TR apresentou maiores valores de transparência, temperatura da água e silicato. ED apresentou maiores valores de condutividade elétrica, turbidez, sólidos totais suspensos, alcalinidade, nitrogênio total, nitrato, nitrogênio amoniacal e ortofosfato. Não houve diferença para o peso seco, peso seco livre de cinzas, clorofila b, carotenóides, feopigmentos e biovolume total entre as estações e dias de sucessão. Contudo, os biovolumes de Bacillariophyceae e Chlorophyceae foram mais representativos em TR, onde a concentração de nutrientes foi menor, enquanto Coscinodiscophycae e Cyanophyceae foram mais representativas em ED. CONCLUSÕES: Somente os maiores valores de clorofila-a em ED confirmaram a hipótese testada.

AIM: This study assessed the phycoperiphyton biomass in two regions submitted to different human impacts on Juara Lake, a coastal ecosystem with multiple uses, to order to test the hypothesis that the sampling sites that receive domestic sewage shows higher biomass values. METHODS: It was installed three experimental structures with artificial substrate (glass slides) in December 2009 in two sampling sites: ED - near the domestic sewage's release; TR - in the area of intensive fish farming (net cages). Samplings were conducted in each experimental structure, after 21, 26 and 31 days for colonization. We evaluated: transparency, electric conductivity, pH, turbidity, total suspended solids, alkalinity, dissolved oxygen, water temperature, total nitrogen, nitrate, nitrite, ammonia nitrogen, total phosphorus, orthophosphate and silicate. The phycoperiphyton was analyzed regarding biomass: biovolume (total and per class); pigments (chlorophyll-a and b and carotenoids) and phaeophytin; dry weight and ash-free dry weight. RESULTS: TR featured higher values of transparency, water temperature and silicate. ED presented greater values of conductivity, turbidity, total suspended solids, alkalinity, total nitrogen, nitrate, ammonia nitrogen, and orthophosphate. No difference was detected between the sites and the succession of days for the dry weight, ash-free dry weight, chlorophyll-b, carotenoids, phaeopigments, and total biovolume. CONCLUSIONS: Nevertheless, the biovolume of Bacillariophyceae and Chlorophyceae were more representative in ED. Only the higher values of chlorophyll confirmed the hypothesis tested.

A lo largo de las costas mexicanas, los florecimientos algales nocivos (FAN) se han vuelto cada vez mas frecuentes y por lo tanto, existe una necesidad urgente de establecer programas de monitoreo para evitar las consecuencias no deseadas por su desarrollo, sobre los ecosistemas naturales y el ser humano. En este trabajo, nosotros analizamos las huellas pigmentarias y la composición de especies de diversas muestras de fitoplancton para evaluar la utilidad que pueden representar estos pigmentos específicos o "huellas pigmentarias" en programas de monitoreo de florecimientos algales nocivos. Los perfiles verticales de muestras de fitoplancton de una laguna costera y muestras de mareas rojas que ocurrieron en un estanque de cultivo de camarón y en una laguna costera, fueron considerados en este estudio. Tanto en muestras verticales como en temporales, entre el 76% y 84% de la densidad celular de dinoflagelados y diatomeas fueron explicados por la variación de su huella específica, mientras que la variación de zeaxantina y la densidad de la cianobacteria Anabaena sp. mostró una relación pobre, la cual fue debida probablemente a la dificultad en el conteo que presenta este grupo al ser analizadas mediante un microscópico invertido. Estos resultados sugieren que la inclusión del análisis de las huellas pigmentarias en los programas del estudio y monitoreo de las algas nocivas sería de gran utilidad

Along the Mexican coast, harmful algae blooms (HAB) have become more frequent, and therefore, there is an urgent need to establish monitoring programs to avoid the undesired consequences of HAB in human and natural ecosystems. In this work, we analyzed the pigment signatures and the species composition from phytoplankton samples to evaluate the utility of the specific pigment "fingerprints" in HAB monitoring programs. Vertical profiles from a coastal lagoon and temporal samples of a red tide occurring in a shrimp-culture pond and in a coastal zone were taken into consideration. Between 76% and 84% of dinoflagellate and diatom cell density was explained by their specific signature variation, in both vertical and temporal samples. Only the variation of zeaxanthin and the cyanobacteria Anabaena sp. showed a poor relationship, probably from difficulties in counting other cyanobacteria present in the samples examined with the microscopic method. These results suggest that inclusion of pigment analysis in the study and monitoring programs dealing with harmful algae would be very useful

Este estudo avalia a distribuição espaço-temporal dos pigmentos fitoplanctônicos na Lagoa Itapeva e sua relação com aspectos hidrodinâmicos. Com relação à distribuição espacial, geralmente um gradiente decrescente no sentido N®S foi observado para os pigmentos, com exceção do verão. Esta inversão observada durante o verão foi influenciada pelo fetch predominante (N-E). Excetuando a primavera, ficou comprovada a existência de heterogeneidade horizontal (ANOVA) nas demais estações do ano. Espacialmente, na primavera a variância vertical foi muito mais significativa (p<0,05) que a horizontal. Os turnos de amostragem sempre exibiram um grau de variabilidade entre as estações do ano, mostrando a existência de um ciclo diurno com relação à concentração de clorofila a. Este comportamento esteve relacionado com o fetch principalmente dos quadrantes NE-SW, perturbando o sistema por ser uma lagoa rasa. Com isso, ficou constatada a influência do regime hidrodinâmico da Lagoa Itapeva na distribuição espaço-temporal dos pigmentos fitoplanctônicos.

This study evaluated the spatial and temporal distribution of phytoplankton pigments in Itapeva Lake and its relationship with hydrodynamic aspects. Regarding spatial distribution, a decreasing N®S gradient was generally observed for the pigments, except in summer. This inversion observed during the summer was influenced by the predominant fetch (N-E). The horizontal heterogeneity was proved (ANOVA) for all seasons of the year, except spring. Spatially in spring, the vertical variance was much more significant (p<0.05) than the horizontal one. The sampling shifts presented a permanent degree of variability among the seasons of the year, showing the existence of a diurnal cycle in the concentration of chlorophyll a. This behavior was related to the fetch, mainly from the NE and SW quadrants, disturbing the system because it is a shallow lake. This confirmed the influence of the Itapeva Lake's hydrodynamic regime on the spatial-temporal distribution of the phytoplankton pigments.

A dinâmica sazonal na densidade de células e na concentração de pigmentos fotossintetizantes das zooxantelas de Montastrea cavernosa foram analisados no período setembro/1999 a setembro/2000 nos Recifes do Picãozinho (06º42'05"/07º07'30" S e 34º48'37"/34º50'00" W), Nordeste do Brasil. Verificou-se que existe um padrão distinto entre estes parâmetros, com maior quantidade de células no período chuvoso e maior concentração de pigmentos fotossintetizantes na época de estiagem. Ambos os parâmetros apresentaram, no entanto, uma nítida redução em seus valores nos meses de maiores índices pluviométricos (junho e julho /1999). Especulamos que tal fato deve estar relacionado com o regime de chuvas que pode variar em magnitude e freqüência, afetando a qualidade ótica da água e o estado fisiológico das células.

The seasonal dynamics of cell density and photosynthetic pigment contents of the zooxanthellae hosted by Montastrea cavernosa were investigated on coastal reefs off Picãozinho (06º42'05"/07º07'30"S and 34º48'37"/34º50'00" W), Northeast Brazil between September 1999 and 2000. A distinct pattern of these parameters was found: cell numbers were greater during the rainy season (autumn/winter) while photosynthetic pigments were greater during the dry season (summer). Both parameters showed drastic reductions during heavy rains (June and July 1999). We speculate that this pattern is largely influenced by the rain cycles which, owing to their magnitude and frequency, affect the water clarity and the seasonal physiological condition of the cells.

Phototrophic bacteria grow in different aquatic systems like coastal lagoons. These systems are characterized for their constant physicochemical fluctuations, nevertheless they are suitable habitats for a number of organisms such as the phototrophic bacteria among others. The aim of this paper is to present the results of the isolation from different strains of purple sulphur bacteria from water samples collected just below the surface of the Tampamachoco lagoon and their characterization using morphological and pigment properties. Eight bacteria strains were isolated. One of them were cocci and the others showed motile bacilli. All isolated strains contained sulphur granules which is characteristic of the members of the Chromatiaceae family. After verifying the purity of the isolated strains, their photosynthetic pigments were analyzed in vivo and extracted with organic solvents (methanol and acetone-methanol). Absorption spectra of these photosynthetic pigments revealed the presence of bacteriochlorophyll a and pigments of the normal spirilloxanthin and rhodopinal series. According with their morphological and pigment characteristics, the isolated strains were members of the Amoebobacter and Chromatium genera.

Las bacterias fotótrofas habitan una gran diversidad de ambientes acuáticos dentro de los cuales están las lagunas costeras. Dichos sistemas, caracterizados por los cambios constantes en sus propiedades fisicoquímicas, son ambientes que albergan un sinnúmero de organismos y las bacterias rojas del azufre están dentro de ellos. El presente trabajo tuvo por objetivos aislar a este tipo de microorganismos a partir de muestras de agua de la laguna de Tampamachoco y caracterizarlas mediante sus propiedades morfológicas celulares y pigmentarias. Se recolectaron muestras de agua del nivel sub-superficial y se aislaron 8 cepas bacterianas. Una de ellas presentó formas esféricas (cocos) y las otras siete fueron bacilos móviles. Todas las cepas acumularon azufre intracelularmente, lo cual es una característica de los miembros de la familia Chromatiaceae. Después de verificar la pureza de las cepas aisladas, se procedió a analizar sus pigmentos fotosintéticos in vivo y sus extractos con disolventes orgánicos (metanol y acetona:metanol). Los espectros de absorción de los pigmentos fotosintéticos mostraron la presencia de bacterioclorofila a y pigmentos de la serie normal de la espiriloxantina y del rodopinal. De acuerdo con sus características morfológicas celulares y pigmentarias se concluye que las bacterias aisladas pertenecen a los géneros Amoebobacter y Chromatium.