Panel 1
Patrizia Borrello, Emanuela Spada
Ostreopsis cf. ovate it is a potentially toxic Bentonic microalga, now present in most of the Italian coastal regions with blooms that can give rise to human intoxication phenomena and toxic effects on benting marine organisms (states of suffering or mortality). The continuous expansion along the Italian coasts of Ostreopsis cf. ovate , of its blooms and the health, environmental and economic problems associated with it, has led to establish a microalga surveillance monitoring program since 2007. This activity has been carried out annually in the summer season by the regional environment agencies (ARPA). The data provided so far by the ARPA, collected and processed by Ispra have clarified the distribution and performance of the blooms at national and regional level. To date, the microalga has been found at least once in the monitoring campaigns carried out so far in 12 coastal regions out of 15. In 2024, the Ostreopsis CF. Ovata is present in 11 coastal regions or in 147/196 stations (75%), while it is absent in all samples taken along the Coste of Emilia-Romagna, Marche, Molise and Veneto.
The indicator measures the trend of the concentration and distribution of Ostreopsis cf. ovate along the Italian marine-cost areas and contributes to the environmental evaluation of bathing waters carried out through the drafting of "bathing water profiles" (DM 30/3/2010, all. E). It can also be associated with the potential toxic and harmful risk on bentonic marine biiogenosis and man. Annex C of the Ministerial Decree 30/3/2010 used up to the 2018 bathing season reports an alert threshold, corresponding to a concentration in the water column of 10,000 cell. The new reference values of alert or emergency to protect human health reported in the ISS guidelines (ISSan report 14/19) were adopted from the 2019 bathing season pursuant to the Ministerial Decree 19/4/2018. Ostreopsis ovata it is a potentially toxic Dinoflagellato Dinoflagellato in Italy since 1989, with very high abundance (blooms), especially in the Bentonic sector. The blooms may involve cases of suffering or mortality of bentonic marine organisms with consequent qualitative worsening of the water. They manifest themselves during the summer and autumn season, often with the concomitant presence of mucilage films of brown-red color to widely cover hard funds and substrates and the presence of flocculi suspended in the water column. The conditions that seem to encourage development and the blooms are: low water depth, presence of rocky and/or macroalga substrates, poor hydrodynamism due to the natural morphology of the coast or in the presence of artificial brushes and barriers for the containment of coastal erosion, weather-marine conditions of great stability, temperatures of the water above 25 ° C can be correlated to the climate change in place.
Evaluate the presence of the microalga, the space-time trend of its proliferation and the potential risk to the bentonic marine environment, man and bathing waters.
Directive Program toxic algae of the Minister of the Environment (Gab/2006/6741/B01); Directive 2006/7/EC; Legislative Decree 152/2006; Legislative Decree 116/2008; DM 30 March 2010; DM 19 April 2018; Directive 2008/56/EC; Legislative Decree 190/2010; RA. MO. GE agreement (France, Principality of Munich, Italy).
Starting in 2006, following the Toxic Algae Directive of the Minister of the Environment and the Protection of the Territory and the Sea, ISPRA has activated the Line of Working "Algal Flowers of Ostreopsis ovata along the Italian coasts "in order to identify elements for a national common sampling strategy, analysis, monitoring, surveillance, information, communication and management of the" toxic algae "phenomenon. In parallel, the Ministry of Health has prepared the guidelines for the" risk management associated with the blooms of Ostreopsis ovata along the Italian coasts" (May 2007). Since one of the purposes of Directive 2006/7/EC is to preserve, protect and improve the quality of the environment and to protect human health by integrating Directive 2000/60/EC, as well as in its Italian transposition, the activities on Ostreopsis were useful for environmental assessments. For this purpose, the blooms are to be indicated in Annex E "Profiles of the waters of bathing" of the Ministerial Decree of 30 March 2010 which reports in the art. 3 as amended by the Ministerial Decree of 19 April 2018 (art. 3 paragraph c) the adoption of the ISPRA operational protocols in surveillance and monitoring activities and the new reference values reported in the ISS guidelines (ISTISAN Report 14/19) pursuant to the aforementioned Ministerial Decree of 19/4/2018.
In particular, the alert phase provides density in water column of 10,000-30,000 cell/l, sufficient hydrodynamism and unfavorable temperatures for flowering or density of 30,000-100,000 cell. While, in the emergency phase entails "density in water column> 30,000 cell.
In addition, the indicator was used for the initial evaluation pursuant to the Marine Strategy Framework Directive (2008/56/EC received with Legislative Decree 190/2010). The R. Mo. ge agreement, with the GDL Gizc- Ostreopsis ovata , he has allowed 200 scholars and Italian, French and Monegasque health authorities to confront national surveillance plans, on the management methods of flowering management methods.
Panel 2
ISPRA Reports: 127/2010,148/2011, 173/2012, 188/2013, 211/2014, 232/2015, 253/2016, 275/2017, 298/2018, 325/2019, 336/2020, 357/2021, 379/2022, 396/2023, 405/2024.
Report SNPA 21/2021, report on the impact indicators of climate change.
ISPRA, Navy Research Notebooks n. 5, 2012
ISS guidelines (ISTISAN report 14/19)
Climate Change and Harmful Benthic Microalgae. Patricia A. Tester, R. Wayne Litaker, Elisa Berdalet. Harmful Algae, Vol, 91, 2020 https://doi. org/10.1016/j. hal.2019.101655 https://www. researchgate. net/publication
Stefano Accoroni, Francesca Neri, Marika Ubaldi, Tiziana Romagnoli, Cecilia Totti, 2024. Trend of Ostreopsis cf. ovata (Dinophyceae) along the Conero Riviera (northern Adriatic Sea) over two decades. Phycologia https://doi. org/10.1080/00318884.2024.2318819
Lack of an environmental reference threshold.
Quantitative study of the effects on the benthos. Determination of an environmental threshold concentration value.
Data quality assessment
Used the data of the coastal harp provided in ISPRA as part of the activity line: "Algal blooms of Ostreopsis ovate along the Italian coasts" (Dir. Toxic algae program n. Gab/2006/6741/B01) sent in the form of relationships and Excel tables by e -mail or ISPRA PEC and loaded on syntai with specific format.
Coastal regions
2010-2024
Indicator assessment
The abundances are expressed as Cell./L, Cell./G FW or Cell./cm 2 respectively for samples taken in water column, macroalga or on hard substrate. All matrices contribute to indicating the figure of the presence of Ostreopsis ovata in the withdrawal station, considering how positivity the presence of Ostreopsis at least once in the monitoring campaign. The concentration in cells/L is compared with the new health reference values reported in the ISS guidelines (ISTISAN Report 14/19) pursuant to Ministerial Decree 19/4/2018. In particular, the emergency phase is reached with density >30,000 cells/L and weather-sea conditions favorable to the formation of aerosols and water sprays. The space-time comparison of abundances shows the trend of blooms at a regional, interregional and national level in the reference year and in previous years. Furthermore, the presence of Ostreopsis also expressed as a percentage of positive sites is reported at regional and national level in the current year and in the observation period.
Monitoring 2024, carried out in 15 coastal regions, made it possible to evaluate the space-time trend of the indicator for a single sampling point. In 6 regions the 30,000 cell/l and in 5 of these also occurred the exceeding of the 100,000 cell/l (table 1). The first is an alert value and the second an emergency value, based on the guidelines of the Ministry of Health. In 2024, no episodes of suffering against marine organisms were observed but only the presence of foam and flocculi in water column (Lazio) and patina on the substrates (Friuli-Venezia Giulia), during the peak of flowering. The percentage of positive sites, which describes the spatial distribution of the indicator, increases to 75% in 2024 (68.7% in 2023). It is not at the moment possible to evaluate the state from an environmental point of view only on the basis of the presence of the alga, as there is no environmental reference value that represents a risk to the health of marine-blind organisms. The Chernoff icon in this case is assigned only on the presence/absence.
A negative trend is attributed since the trend in the 15 years considered does not show a clear turnaround. In fact, since 2010 there has been an increase over time, of over 27 percentage points, of the sites with the presence of Ostreopsis ovata (2010: 48.3%, 2024: 75%) (Figure 2 and Table 3). There are also minimal variations in the number of sites with the presence of the microalga in the period 2010-2015 and larger between 2016 and 2024. The maximum value, equal to 75%, is recorded in 2024.
Data
Figure 1: Presence of Ostreopsis cf. ovated along the Italian coasts (2024)
ISPRA processing on data from coastal ARPA
Tabella 1: Presenza di Ostreopsis cf. ovata lungo le coste italiane (2024)
Elaborazione ISPRA su dati delle ARPA costiere
Tabella 2: Presenza e abbondanza di Ostreopsis ovata lungo le coste italiane (2024)
Elaborazione ISPRA su dati delle ARPA costiere
Le celle vuote indicano assenza di monitoraggio nella matrice considerata
Tabella 3: Percentuale dei siti con presenza di Ostreopsis cf. ovata a livello regionale (2010-2024)
Elaborazione ISPRA su dati ARPA costiere
n.d. = non disponibile
Figura 2: Percentuale dei siti con presenza di Ostreopsis cf. ovata (2010-2024)
Elaborazione ISPRA su dati ARPA costiere
In 2024, the monitoring of the potentially toxic Ostreopsis CF. Ovate were carried out along the coasts of the 15 coastal regions (Table 1 and Figure 1). The investigations were carried out by the regional agencies for the environment (harp) both for the purposes of water control activities intended for bathing, in fulfillment to current legislation (Ministerial Decree 30/3/2010, Ministerial Decree of 19 April 2018 and Legislative Decree 116/08 and SS. MM. II), either in the context of Arpa/Region projects, or as activities falling within the monitoring of the potentially toxic species in the waters intended for the water intended for the waters Mollluschiculture (Friuli-Venezia Giulia).
196 sampling stations have been identified and monitored with hydromorphological characteristics suitable for the development of the microalga (presence of macroalgae, rocky substrates, shallow waters and moderate hydrodynamism, natural cliffs and frangiflucum barriers or brushes) or which have recorded in previous years presence and/or flowers of the microalga. The monitoring was generally performed in the period June-September 2024, anticipated in May in Emilia-Romagna and Molise and postponed in some cases in October (Marche and Veneto). The frequency of the fortnightly or monthly sampling was intensified in cases of exceeding the reference values (30,000 cell/l, 100,000 cell/l), as indicated in the emergency phases described in the surveillance plans of the guidelines of the Ministry of Health contained in the Ministerial Decree 30/3/2010 and DM 19/4/2018 and in the ISTISAN 14/19 report.
Samples of water and macroalgae were taken, according to shared methodologies. Furthermore, the chemical-physical parameters of the water were also detected and registered on a special field card, information on the sampling site, any signs of manifest microalgal flowering or states of suffering against marine organisms (curls, mythilians, starfish, fish, macroalgae, etc.).
In 2024 Ostreopsis CF. Ovata was found in 11 coastal regions, while it is absent in all samples taken along the Coasts of Veneto, Emilia-Romagna, Marche and Molise (Table 2) and is present at least once in 147/196 stations (75%), considering all the types of sampled matrices (Table 1 and Figure 1). This means that the sites in which the presence of the microalga is noted, being "to potential risk of toxic algal proliferation" are to be reported in the environmental profile of the bathing waters to be monitored through monitoring (DM 30/3/2010 and 19/4/2018). In addition, the health reference value of alert equal to 30,000 cells/L was exceeded at least once in 22 monitoring sites (calculation carried out only on the water matrix, Figure 1) and the emergency health value of 100,000 cells/L has been exceeded at least once in 8 sites (Abruzzo 1, Calabria 1, Puglia 2, Sicily 3, Tuscany 1). The first surveys (at low concentrations) are found in June in Basilicata, Calabria, Campania, Lazio, Liguria, Puglia, Sardinia and Sicily, while the highest abundances above 30,000 cells/L are distributed between June and September in Abruzzo, Calabria, Lazio, Puglia, Sicily and Tuscany. In particular, in the last three regions mentioned, both the 30,000 cell/l has occurred and the exceeding of the 100,000 cells/l. The maximum concentration value was equal to 1,500.266 Cell./L found in one site in Calabria. The two Hot-Spot sites, Hotel Riva del Sole (Puglia) and Accensor Passetto (Marche), which every year had high and recurrent abundances with values greater than 30,000 cell/L, in 2024 show a trend contrary to the usual, with concentrations ranging from 0 to a maximum of 4,473 cell/l in the "Hotel Riva del Sole" station and even abundance equal to 0 cell/l in the whole period of sampling "Lift walk". This turnaround will be investigated and confirmed in the next monitoring cycles.
Furthermore, based on the data collected in previous years, the duration of flowering varies from a few days to 7-10 days but depends, however, on the environmental conditions that favor and maintain it