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The 18th International Conference on Harmful Algae (ICHA), From ecosystems to socio-ecosystems, 21-26 October 2018, Nantes, France.-- 1 page, Kryptoperidinium foliaceum (Stein) Lindemann is a harmful dinoflagellate categorized as high biomass bloom forming species. Its blooms have been associated with massive water discolorations, but also with fish mortality events. The species is widely distributed with a great tolerance range to salinity, being reported from almost freshwater to transitional ecosystems (i.e. coastal lagoons, marshes and estuaries), but also from hypersaline tidal creeks. Despite its wide distribution, information on the morphology, genetic and ecology of K. foliaceum is scarce. Recurrent blooms of K. foliaceum have been detected in Calich Lagoon (North West coast of Sardinia, Italy) in the last decade. The species was also seldom observed in Santa Giusta Lagoon (central west coast of Sardinia, Italy), where bloom events have not been registered in recent years. The aim of the present study was to investigate morphological, molecular and ecological features of K. foliaceum from the two lagoons. Firstly, the long-term ecological data from the field (2008-2015 for Calich, and 1990-2002 and 2010-2018 for Santa Giusta) were analyzed to characterize the two lagoons and the temporal dynamic of the species. Therefore, two cultured K. foliaceum strains from Calich and Santa Giusta lagoons were characterized for morphology and genetic. In addition, the growth rates of the two strains were determined at three different temperatures (11°C, 20°C and 30°C) and six salinities (5, 10, 20, 30, 40, 50). Field data showed the constant presence of K. foliaceum in Calich along the series, with highest cell densities mainly observed in spring (maximum of 4 x 10 6 cell L-1 in April 2015). On the contrary, the species was sporadically observed in Santa Giusta in the last decade, with cell densities usually rather low (

Chattonella species in a Mediterranean lagoon (Santa Giusta Lagoon, Sardinia, Italy) were identified by applying a molecular approach to fixed natural phytoplankton samples collected over the last two decades. Like the other raphidophytes, Chattonella cells are naked and lose their shape when fixed, making species identification difficult on the basis of their morphological characteristics. Employing species-specific primers (oBTG-005-F, oBTG-027-R, oBTG-028-R) for the amplification of the ITS-5.8S rDNA region, we established the occurrence of C. subsalsa in fixed natural phytoplankton samples collected in coincidence with fish death events. Additionally, we established the presence of the recently discovered C. cf. subsalsa Adriatic genotype by analysing cellular cultures obtained from the same lagoon in 2013. This is the second worldwide record of C. cf. subsalsa Adriatic genotype. Our results revealed that the species-specific primers oBTG-005-F and oBTG-028-R distinguished this new genotype only when present singularly. This study provides valuable data that increase knowledge of C. subsalsa genotypes and of the long-term occurrence of Chattonella blooms in a transitional ecosystem through the use of samples up to 20 years old., Se identificaron especies de Chattonella mediante la aplicación de técnicas moleculares en muestras naturales de fitoplancton. Las muestras fueron recogidas y fijadas durante las últimas dos décadas en una laguna litoral mediterránea (Laguna de Santa Giusta, Cerdeña, Italia). Al igual que otras rafidoficeas, las células de Chattonella no poseen teca y, por lo tanto, pierden su forma cuando se fijan lo que dificulta la identificación basada en características morfológicas. Con el uso de cebadores específicos a nivel de especie (OBTG-005-F, OBTG-027-R, OBTG-028-R) diseñados para la amplificación de la región ITS- 5.8S rDNA, se detectó la presencia de C. subsalsa en las muestras recogidas en periodos coincidentes con eventos de muerte de peces. A través del análisis de los cultivos celulares obtenidos de la misma laguna en el año 2013, se identificó la presencia, por segunda vez a nivel mundial, del recientemente descubierto genotipo Adriático de C. cf. subsalsa. Los resultados revelaron que los cebadores oBTG-005-F y oBTG-028-R amplifican este nuevo genotipo sólo cuando está presente individualmente. En este estudio se presentan datos relevantes para el conocimiento de los genotipos de C. subsalsa y sobre la presencia recurrente de proliferaciones de especies de Chatonella en un ecosistema de transición a través de la utilización de muestras recogidas durante los últimos veinte años y analizadas hoy en día.

1 - Water quality in four Sardinian lagoons (western Mediterranean Sea) was assessed using the Multimetric Phytoplankton Index (MPI), which is consistent with the EU Water Framework Directive. The index was developed using data on phytoplankton abundances, species structure and chlorophyll a concentrations in Venice Lagoon, Italy. 2 - The aim of this study was to test the MPI on a larger geographical scale and across a range of lagoon types. Therefore, it was applied to assess water quality in the Cabras, S’Ena Arrubia, Santa Giusta and Calich lagoons in Sardinia. These lagoons are all “choked”, but exhibit a range of sizes and morphometric features. They are directly affected by human activity within the lagoons themselves, such as fisheries, aquaculture and the construction of dams and canals, and are indirectly affected by anthropogenic activities in their catchments, including intensive agriculture, industrial activity and urban development. 3 - The data used in the present study were collected monthly over a period of 4 years (Calich, Santa Giusta and S’Ena Arrubia) to 7 years (Cabras). Samples were collected at three stations at each of the Cabras, Santa Giusta and Calich lagoons, and at two stations at the S’Ena Arrubia Lagoon, providing a total of 220 samples. 4 - The water quality in three of the four lagoons investigated (Cabras, S’Ena Arrubia and Calich) was classified as bad using the MPI. Among these three, water in Cabras Lagoon exhibited the worst condition. Water quality in Santa Giusta Lagoon was classified as poor using the MPI. 5 - Although we present preliminary results that require further verification, the index appears to be a useful tool for assessing the ecological status of typical Mediterranean lagoons.

An intense proliferation of cyanobacteria in Cabras Lagoon was investigated over a period of two years (July 2007 to June 2009). The influence of environmental and meteorological parameters in the lagoon on temporal variations in cyanobacteria orders was assessed. For 17 months, Chroococcales was the only cyanobacterial order observed in the lagoon. Cyanobium-type cells (Reynolds functional group Z) were the most abundant phytoplankton taxon during this period. In the following months, drastic changes in the cyanobacteria assemblages occurred simultaneously with constant, intense rainfall that led to a sudden drop in the lagoon’s salinity. The succession of autumn–winter Oscillatoriales (Planktothrix sp. and Pseudanabaena catenata; Reynolds functional group S1) and late spring growth of Nostocales (Aphanizomenon gracile, Aphanizomenon aphanizomenoides, and Anabaenopsis circularis; Reynolds functional group H1) was monitored. Canonical Correspondence Analysis was carried out to quantify the influence of environmental variables, and indicated strong relationships between Chroococcales and salinity, Oscillatoriales and higher values of SRP and the DIN/SRP ratio, and Nostocales and lower nutrient concentrations, the DIN/SRP ratio and salinity., Durante dos años (julio 2007-junio 2009) se monitoreó una proliferación intensa de cianobacterias en la laguna de Cabras, así como los parámetros ambientales y climáticos que determinaron sus variaciones temporales. Durante 17 meses, Chroococcales fue el único orden de cianobacterias en la laguna, del cual células similares a Cyanobium (grupo funcional Z según Reynolds) fueron las más importantes en cuanto a abundancia. En los meses siguientes, las cianobacterias sufrieron cambios drásticos, que ocurrieron simultáneamente con lluvia constante e intensa que dio lugar a una caída brusca de la salinidad de la laguna. Se monitoreó también la sucesión de Oscillatoriales en otoño-invierno (Planktothrix sp. and Pseudanabaena catenata; grupo funcional S1 según Reynolds) y el crecimiento en primavera de Nostocales (Aphanizomenon gracile, Aphanizomenon aphanizomenoides, y Anabaenopsis circularis; grupo funcional H1 según Reynolds). Análisis de Correspondencia Canónica permitieron cuantificar la influencia de las variables ambientales, indicando una estrecha relación entre Chroococcales y salinidad, Oscillatoriales y altos niveles de SRP y proporción DIN/SRP, y Nostocales y bajos niveles de nutrientes, proporción DIN/SRP y salinidad.