Resumo: A maioria dos estudos sobre Dinophysis acuminata no Brasil ocorreram na região sul, onde as florações são recorrentes. Em 2016, a presença de D. acuminata causou o primeiro embargo comercial da produção e consumo de espécies de moluscos do estado de São Paulo, sudeste do Brasil. Várias espécies de microalgas potencialmente nocivas foram relatadas na Baía de Guanabara (BG), incluindo espécies tóxicas de Dinophysis, mas estas foram reportadas apenas como ocasionais e em baixas densidades. A presente nota é o primeiro relato de um evento de alta densidade (~ 105 células L-1) do complexo D. acuminata/D. saculus na BG. As espécies foram identificadas através de microscopia eletrônica de varredura e de campo claro. A maioria das células estudadas possuía uma placa hipossômica dorsalmente convexa, e tinha dimensões típicas de D. acuminata. No entanto, a associação observada com águas estuarinas mais quentes e menos salinas indicaria que a espécie seria D. saculus. Qualquer que seja o caso, com base nas altas densidades observadas aqui, recomendamos o monitoramento contínuo da presença de Dinophysis na BG.

Abstract: Most studies of Dinophysis acuminata in Brazil are for the southern region, where blooms are recurrent. In 2016, the presence of D. acuminata caused the first-ever production and consumption of species of mollusks commercial embargo from the state of Sao Paulo, Southeast Brazil. Potentially toxic species of Dinophysis have been reported in Guanabara Bay (GB) but only occasionally and in low densities. The present note is the first report of a high-density event (~105 cells L-1) of D. acuminata/D. sacculus complex in GB. D. acuminata/D. sacculus complex species were identified using scanning-electron and inverted-light microscopy. Most of the studied cells possessed a dorsally convex hyposomal plate and had dimensions typical of D. acuminata. However, the observed association with warmer and less saline estuarine waters would indicate that the species could be D. sacculus. Whatever the case, based on the high cell densities observed here, we recommend a continued monitoring for Dinophysis presence in GB.

ABSTRACT To describe potential intraspecific variation in phosphorus incorporation in two strains of Phaeodactylum tricornutum (Bohlin), Ub3 and Ub7, alkaline phosphatase (AP) activity was evaluated via enzyme-labeled fluorescence assay. Analysis using the probe ELF-97(r) provides individual evaluation, and therefore can determine the nutritional status of inorganic phosphorus in phytoplanktonic cells. Bioassays compared the control treatment to both phosphate-enriched and phosphate-depleted treatments by varying only the phosphate concentration in the media. The P. tricornutum strains exhibited differences in their development when incubated in the phosphate-enriched media. The development of the Ub7 strain differed by exhibiting "luxury uptake" and utilization of organic phosphorus, and the alkaline phosphatase analysis indicated limitations of this clone under such conditions. The Ub7 strain showed higher AP activity, when compared to Ub3, in the P-enriched condition. P. tricornutum presented increases in AP activity and low variation in Surface/Volume ratio, by increasing biovolume and its maximum linear dimension, as strategies for phosphate incorporation. Our results highlight intraspecific differences in alkaline phosphatase activity, and hence differences in the incorporation of organic phosphorus, as the tested species regulated enzymatic activity under different external phosphate concentrations.

A contribuição dos canais estuarinos de Santos e São Vicente para a eutrofização da baía de Santos foi avaliada quantificando-se o transporte instantâneo de sal, fosfato e nitrogênio inorgânico dissolvido (NID), material em suspensão orgânico (MSO) e inorgânico (MSI) e clorofila-a, durante a estação seca (inverno austral- Agosto/1999) e chuvosa (verão austral- Janeiro/ 2000). As amostragens foram realizadas em períodos de sizígia e quadratura, durante as marés enchentes e vazantes, nas secções transversais das bocas dos canais de São Vicente e Santos. Os valores de transporte instantâneo obtidos durante o período de amostragem indicaram exportação de NID, principalmente sobre a forma de N-NH4 (valor máximo de 1155,1 g s-1) na estação chuvosa; importação de fosfato durante a estação seca (máximo de 385,6 g s-1) e exportação de MSI, MSO e clorofila-a em períodos de maior contribuição fluvial. Estes resultados indicam uma importante contribuição dos canais estuarinos de Santos e São Vicente para a eutrofização da baía de Santos, especialmente durante o período chuvoso.

The contribution of the polluted São Vicente and Santos estuarine channels to the eutrophication of Santos bay was assessed through the quantification of instantaneous transport of salt, dissolved inorganic nitrogen (DIN) and phosphate, organic and inorganic matter (OSM and ISM) and chlorophyll-a (Chl-a), during dry (austral winter- August/ 1999) and rainy (austral summer- January/2000) seasons. Samplings were carried out during spring and neap tides, in flood and ebb phases, in two transversal sections at the mouths of the São Vicente and Santos channels. Instantaneous transport values generally indicated importation of salt to the estuarine channels, exportation of DIN to the bay, mainly as N-NH4, at a maximum rate of 1155.1 g s-1 during the rainy season; importation of phosphate during the dry season (maximum of 385 g s-1) and exportation of ISM, OSM and Chl-a during periods of greater freshwater discharge. These results demonstrate the great contribution made by the Santos and São Vicente estuaries to the eutrophication of Santos bay, especially in the rainy season.