First results of phytoplankton spatial dynamics in two NW-Mediterranean bays from Chlorophyll-a estimates using Sentinel 2: potential implications for aquaculture

Shellfish aquaculture has a major socioeconomic impact on coastal areas, thus it is necessary to develop support tools for its management. In this sense, phytoplankton monitoring is crucial, as it is the main source of food for shellfish farming. The aim of this study was to assess the applicability of Sentinel 2 multispectral imagery (MSI) to monitor the phytoplankton biomass at Ebro Delta bays and to assess its potential as a tool for shellfish management. In situ chlorophyll-a data from Ebro Delta bays (NE Spain) were coupled with several band combination and band ratio spectral indices derived from Sentinel 2A levels 1C and 2A for time-series mapping. The best results (AIC = 72.17, APD < 10%, and MAE < 0.7 mg/m3) were obtained with a simple blue-to-green ratio applied over Rayleigh corrected images. Sentinel 2–derived maps provided coverage of the farm sites at both bays allowing relating the spatiotemporal distribution of phytoplankton with the environmental forcing under different states of the bays. The applied methodology will be further improved but the results show the potential of using Sentinel 2 MSI imagery as a tool for assessing phytoplankton spatiotemporal dynamics and to encourage better future practices in the management of the aquaculture in Ebro Delta bays.info:eu-repo/semantics/publishedVersio

First results of phytoplankton spatial dynamics in two NW-Mediterranean bays from chlorophyll-a estimates using sentinel 2: potential implications for aquaculture

Shellfish aquaculture has a major socioeconomic impact on coastal areas, thus it is necessary to develop support tools for its management. In this sense, phytoplankton monitoring is crucial, as it is the main source of food for shellfish farming. The aim of this study was to assess the applicability of Sentinel 2 multispectral imagery (MSI) to monitor the phytoplankton biomass at Ebro Delta bays and to assess its potential as a tool for shellfish management. In situ chlorophyll-a data from Ebro Delta bays (NE Spain) were coupled with several band combination and band ratio spectral indices derived from Sentinel 2A levels 1C and 2A for time-series mapping. The best results (AIC = 72.17, APD < 10%, and MAE < 0.7 mg/m3) were obtained with a simple blue-to-green ratio applied over Rayleigh from Sentinel 2A levels 1C and 2A for time-series mapping. The best results (AIC = 72.17, APD < 10%, and MAE < 0.7 mg/m3) were obtained with a simple blue-to-green ratio applied over Rayleigh corrected images. Sentinel 2–derived maps provided coverage of the farm sites at both bays allowing relating the spatiotemporal distribution of phytoplankton with the environmental forcing under different states of the bays. The applied methodology will be further improved but the results show the potential of using Sentinel 2 MSI imagery as a tool for assessing phytoplankton spatiotemporal dynamics and to encourage better future practices in the management of the aquaculture in EbroPeer ReviewedPostprint (published version

Novel ovatoxin-g and putative palytoxin from Ostreopsis cf. ovata (NW Mediterranean Sea): gaining structural information through high resolution mass spectrometry

The harmful blooms of the benthic dinoflagellate Ostreopsis cf. ovata are a concern in the coastlines of the Mediterranean Sea, since it produces a wide range of palytoxin-like compounds listed among the most potent marine toxins. This study focused on two analogs of palytoxin found in cultures of two Ostreopsis cf. ovata strains isolated from the south of Catalonia (NW Mediterranean Sea) in August, 2011. Our strains produced two novel compounds, ovatoxin-g and an isomer of palytoxin whose structures had not been elucidated yet. Although the quantity of these compounds was not sufficient for a full NMR-based structural elucidation, thus we studied their structure through Liquid Chromatography Electro Spray Ionization High Resolution Mass Spectrometry (LC-ESI-HRMS) in positive ion mode, following the LC-HRMSn approach developed by Ciminiello et al. Under the used MS conditions, the molecules underwent fragmentation at many sites of their backbone and a large number of diagnostic fragment ions were identified. Their MSn spectra were investigated in light of the reported structure of ovatoxin-a and palytoxin from Palythoa tuberculosa (commercially available as analytical standard). As a result, ovatoxin-g was tentatively identified as 46-deoxy-ovatoxin-a, while the novel isomer of palytoxin would have two additional hydroxyl groups (one in the region C1 and C8 and one at C42) and two hydroxyl lacking (one at C17 and one in the region C53 and C79, compared to palytoxin standard. Ovatoxin-g and putative palytoxin were the least abundant palytoxin-like compounds (0.8% and 0.4% respectively) in a toxin profile dominated by ovatoxin-a (53%). Ovatoxin-b to –e (30%, 4%, 6%, 7% respectively) were also present, while production of ovatoxin-f was not observed. These strains are still under investigation to confirm the presence of other potentially new palytoxin congeners

Star 2013, Linea 1 "Validation of LC-MS/MS for Palytoxins, the emerging threat to humans in the Mediterranean Area"

Il progetto rappresenta la Start-up phase di un progetto Europeo o extra-Europeo da sottomettere entro il 2016 che ha come obiettivo la validazione di un metodo LC-MS/MS per le palitossine negli alimenti marini e la preparazione degli standard, che attualmente mancano per le palitossine. La disponibilità di metodi validati rappresenta la base razionale per una corretta gestione del rischio di qualsiasi intossicazione alimentare e, nel campo delle tossine emergenti (quali sono le palitossine), rappresenta il primo inevitabile passo per un'adeguata comprensione e gestione del fenomeno. La disponibilità di standard è pre-requisito per studi tossicologici in-vivo, necessari per una corretta caratterizzazione del rischio. Durante la start-up phase, verranno intraprese attività preliminari analitiche e preparative che rappresentano la base degli studi di validazione e della preparazione degli standard. Queste includono: la validazione intra-lab di un metodo LC-HRMS per la palytossina; studi di prevalidazione; avvio delle colture algali e del lavoro di isolamento (che continuerà nell'ambito del progetto successivo)

Insights from an international stakeholder consultation to identify informational needs related to seafood safety

Food safety assessment and communication have a strong importance in reducing human health risks related to food consumption. The research carried out within the ECsafeSEAFOOD project aims to assess seafood safety issues, mainly related to non-regulated priority environmental contaminants, and to evaluate their impact on public health. In order to make the research results accessible and exploitable, and to respond to actual stakeholders' demands, a consultation with international stakeholders was performed by means of a survey. The focus was on policy and decision makers, food producers and processors, and agencies (i.e. EU and National or Regional agencies related to Food Safety or Public Health) and consumer organisations. The survey considered questions related to: seafood safety assessment and mitigation strategies, availability of data, such as the level of information on different contaminants, and communication among different stakeholder groups. Furthermore, stakeholders were asked to give their opinion on how they believe consumers perceive risks associated with environmental contaminants. The survey was distributed to 531 key stakeholders and 91 responses were received from stakeholders from 30 EU and non-EU countries. The main results show that communication between different groups of stakeholders needs to be improved and that there is a deficit of information and data in the field of seafood safety. This pertains mainly to the transfer of contaminants between the environment and seafood, and to the diversity of environmental contaminants such as plastic additives, algal toxins and hormones. On-line tools were perceived to be the most useful communication channel

Toxicity screening of a Gambierdiscus australes strain from the Western Mediterranean sea and identification of a novel maitotoxin analogue

Dinoflagellate species of the genera Gambierdiscus and Fukuyoa are known to produce ciguatera poisoning-associated toxic compounds, such as ciguatoxins, or other toxins, such as maitotoxins. However, many species and strains remain poorly characterized in areas where they were recently identified, such as the western Mediterranean Sea. In previous studies carried out by our research group, a G. australes strain from the Balearic Islands (Mediterranean Sea) presenting MTX-like activity was characterized by LC-MS/MS and LC-HRMS detecting 44-methyl gambierone and gambieric acids C and D. However, MTX1, which is typically found in some G. australes strains from the Pacific Ocean, was not detected. Therefore, this study focuses on the identification of the compound responsible for the MTX-like toxicity in this strain. The G. australes strain was characterized not only using LC-MS instruments but also N2a-guided HPLC fractionation. Following this approach, several toxic compounds were identified in three fractions by LC-MS/MS and HRMS. A novel MTX analogue, named MTX5, was identified in the most toxic fraction, and 44-methyl gambierone and gambieric acids C and D contributed to the toxicity observed in other fractions of this strain. Thus, G. australes from the Mediterranean Sea produces MTX5 instead of MTX1 in contrast to some strains of the same species from the Pacific Ocean. No CTX precursors were detected, reinforcing the complexity of the identification of CTXs precursors in these regions.European Food Safety Authority | Ref. GP/EFSA/AFSCO/2015/03Xunta de Galicia | Ref. ED481A-2018/207Generalitat de Catalunya | Ref. CERC

Capacity of the potentially toxic diatoms Pseudo-nitzschia mannii and Pseudo-nitzschia hasleana to tolerate polycyclic aromatic hydrocarbons

This study investigates the effects of polycyclic aromatic hydrocarbons (PAHs) on two potentially toxic Pseudonitzschia hasleana and P. mannii, isolated from a PAH contaminated marine environment. Both species, maintained in non-axenic cultures, have been exposed during 144 h to increasing concentrations of a 15 PAHs mixture. Analysis of the domoic acid, showed very low concentrations. Dose?response curves for growth and photosynthesis inhibition were determined. Both species have maintained their growth until the end of incubation even at the highest concentration tested (120 ?g l-1), Nevertheless, P mannii showed faster growth and seemed to be more tolerant than P. hasleana. To reduce PAH toxicity, both species have enhanced their biovolume, with a higher increase for P. mannii relative to P hasleana. Both species were also capable of bioconcentrating PAHs and were able to degrade them probably in synergy with their associated bacteria. The highest biodegradation was observed for P. mannii, which could harbored more efficient hydrocarbon-degrading bacteria. This study provides the first evidence that PAHs can control the growth and physiology of potentially toxic diatoms. Future studies should investigate the bacterial community associated with Pseudo-nitzschia species, as responses to pollutants or to other environmental stressors could be strongly influence by associated bacteria

Occurrence of cyclic imines in European commercial seafood and consumers risk assessment

Cyclic imines constitute a quite recently discovered group of marine biotoxins that act on neural receptors and that bioaccumulate in seafood. They are grouped together due to the imino group functioning as their common pharmacore, responsible for acute neurotoxicity in mice. Cyclic imines (CIs) have not been linked yet to human poisoning and are not regulated in the European Union (EU), although the European Food Safety Authority (EFSA) requires more data to perform conclusive risk assessment for consumers. Several commercial samples of bivalves including raw and processed samples from eight countries (Italy, Portugal, Slovenia, Spain, Ireland, Norway, The Netherlands and Denmark) were obtained over 2 years. Emerging cyclic imine concentrations in all the samples were analysed on a LC-3200QTRAP and LC-HRMS QExactive mass spectrometer. In shellfish, two CIs, pinnatoxin G (PnTX-G) and 13-desmethylspirolide C (SPX-1) were found at low concentrations (0.1–12 µg/kg PnTX-G and 26–66 µg/kg SPX-1), while gymnodimines and pteriatoxins were not detected in commercial (raw and processed) samples. In summary, SPX-1 (n: 47) and PnTX-G (n: 96) were detected in 9.4% and 4.2% of the samples, respectively, at concentrations higher than the limit of quantification (LOQ), and in 7.3% and 31.2% of the samples at concentrations lower than the LOQ (25 µg/kg for SPX-1 and 3 µg/kg for PnTX-G), respectively. For the detected cyclic imines, the average exposure and the 95th percentile were calculated. The results obtained indicate that it is unlikely that a potential health risk exists through the seafood diet for CIs in the EU. However, further information about CIs is necessary in order to perform a conclusive risk assessment