Benthic studies in LTER sites: the use of taxonomy surrogates in the detection of long-term changes in lagoonal benthic assemblages

In benthic studies, the identification of organisms at the species level is known to be the best source for ecological and biological information even if time-consuming and expensive. However, taxonomic sufficiency (TS) has been proposed as a short-cut method for quantifying changes in biological assemblages in environmental monitoring. In this paper, we set out to determine whether and how the taxonomic complexity of a benthic assemblage influences the results of TS at two different long-term ecological research (LTER) sites in the Po delta region (north-eastern Italy). Specifically, we investigated whether TS can be used to detect natural and human-driven patterns of variation in benthic assemblages from lagoonal soft bottoms. The first benthic dataset was collected from 1996 to 2015 in a “choked” lagoon, the Valli di Comacchio, a lagoon characterised by long water residence times and heavy eutrophication, while the second was collected from 2004 to 2010 in a “leaky” lagoon, the Sacca di Goro, a coastal area with human pressure limited to aquaculture. Univariate and multivariate statistical analyses were used to assess differences in the taxonomic structure of benthic assemblages and to test TS on the two different datasets. TS seemed to work from species to family level at both sites, despite a higher natural variability of environmental conditions combined with multiple anthropogenic stressors. Therefore, TS at the family level may represent effective taxonomic surrogates across a range of environmental contexts in lagoon environments. Since the structure of the community and the magnitude of changes could influence the efficiency of taxonomic surrogates and data transformations in long-term monitoring, we also suggest periodic analyses at finer taxonomic levels in order to check the efficiency of the application of taxonomic substitutes in routine monitoring programmes in lagoon systems

Long-term changes of the trophic status in transitional ecosystems of the northern Adriatic Sea, key parameters and future expectations: The lagoon of Venice as a study case.

The determination of the trophic status of transitional ecosystems from the physico-chemical and biological point of view is one of the requirements of the European Water Framework Directive (WFD 2000/60/EC). In Italy, its determination is implemented by the Regional Agencies for Environmental Protection (ARPAs) that have activated multi-annual monitoring programs. However, as the availability of funds is increasingly scarce, the number of environmental parameters to detect environmental changes should be conveniently managed. The high number of environmental parameters, nutrient and macrophyte datasets available for the LTER-Italia site “Venice lagoon” can be an useful tool to analyze the trophic changes over recent years and to foresee environmental evolutions. Nutrient data on a spatial basis have been available since 1948, whereas macroalgal maps date back to 1980. The aim of this paper is to highlight the changes of the trophic status of the lagoon since the middle of the 20th century by considering the concentrations of nutrients in the surface sediments and in the water column, the variation of some physico-chemical parameters and the biomass of macroalgae and also to foresee the way it will possibly evolve. In fact, after many anthropogenic impacts that in the second half of the 20th century affected the lagoon, starting fromthe year 2010, the ecological status is progressively improving. Nutrients show a significant reduction both in the water column and in surface sediments, and the macrophytes are represented by species of higher ecological value while the opportunistic species such as the Ulvaceae are in strong regression

Trends of Nitrogen and Phosphorus in Surface Sediments of the Lagoons of the Northern Adriatic Sea

The analysis of nutrient concentrations in surface sediments is a reliable tool for assessing the trophic status of a water body. Nitrogen and phosphorus concentrations are strongly related to the sediment characteristics but are mainly driven by anthropogenic impacts. The results of the determination of total nitrogen and total inorganic and organic phosphorus in surface sediments of the lagoons and ponds of the northwestern Adriatic Sea (Marano-Grado, Venice, Po Delta, Comacchio Valleys, Pialassa della Baiona) show the merit of this approach. Indeed, when previous data are available, the ratio between the actual and background values can provide useful information on the trophic changes that have occurred in the most recent times, and the results can also explain the conditions present in less studied environments. In this context, numerous studies performed in the Venice lagoon since the second half of the 20th century during different environmental scenarios provide mean concentration ranges and propose the main causes of changes. The results of single datasets available for the other lagoons fall into scenarios that occurred in the Venice lagoon. At present, the most eutrophic basins are Pialassa della Baiona, the Po Delta lagoons and ponds and the Comacchio valleys due to industrial effluents, fish farming and clam harvesting, respectively, whereas the Venice lagoon is now experiencing environmental recovery

Sediment contamination by heavy metals and PAH in the Piombino Channel (Tyrrhenian Sea).

Sediment contamination is of major concern in areas affected by heavy maritime traffic. The spatial variation and contamination of 11 trace elements and 17 PAHs in surface sediments were studied along a 31 km transect along the seaway from the port of Piombino (Tuscany) to the port of Portoferraio (Elba Island) in the Northern Tyrrhenian Sea. Heavy metal contamination was detected at sites near Piombino (Ni, Pb, Hg, Cu and Zn) and at sites near Portoferraio (Pb, Zn, Hg, Cr and Cd). Each of the 35 sampled sites showed PAH contamination, with the highest concentrations at sites near Portoferraio. The most abundant isomers detected were 2- and 4-ring PAHs. PAH ratio analysis showed a prevalence of PAHs of pyrolytic origin. High values of PAHs and heavy metals were related to high sediment water content, TOC, silt, and clay content. Arsenic increased with increasing depth. The correlation between concentrations of metals and PAHs suggests common anthropogenic sources and is of concern for possible synergistic adverse effects on the biota

Assess the environmental health status of macrophyte ecosystems using an oxidative stress biomarker. Case studies: The Gulf of Aqaba and the Lagoon of Venice

Abstract The aim of this work was to evaluate the implementation of the oxidative stress biomarker (LPO) for the assessment and monitoring of the ecological status of macrophyte in relation to potentially toxic elements (PTEs) in the Gulf of Aqaba (Jordan) and the Lagoon of Venice (Italy). Results showed that the anthropic influences related to PTEs of the examined areas are evident. Moreover, changes in the LPO levels can precede significant changes in ecological health status of macrophyte ecosystems that can be used in the future as an early warning tool for the assessment and monitoring of polluted ecosystems worldwide

New macroalgae and rare species in the fishing ponds of the Venice Lagoon and ecological assessment.

Macrophyte assemblages were studied in the whole Venice lagoon, including some close fishing ponds, in order to assess the ecological status of this transitional system. During sampling some new or rare species were recorded highlighting the highest ecological status of areas close to tidal expansion and protected from anthropic impacts

Temporal variation of floatable plastic particles in the largest Italian river, the Po

none7We investigated the temporal concentration of floatable plastic particles in the Po river, the largest contributor of freshwater to the Adriatic Sea. Surface waters were sampled in 2019 with a Manta trawl, with almost bimonthly frequency. In total, 5063 plastic particles were collected, 80.6% of which were microplastics (<5 mm). Characterization through FT-IR spectroscopy evidenced 7 polymers, of which polyethylene, polypropylene and polystyrene accounted for 40.5%, 25.7%, and 14.9%, respectively. The highest plastic concentration was recorded in December (3.47 particles m-3; 5.89 mg m-3), while the lowest in August (0.29 ± 0.01 particles m-3; 0.22 ± 0.08 mg m-3). We estimated the annual load of floatable plastic particles carried by the Po river to be 145 tons. Plastic particle load was correlated with the hydraulic regime, and was higher in autumn and spring months.mixedMunari, Cristina; Scoponi, Marco; Sfriso, Andrea A.; Sfriso, Adriano; Aiello, Jacqueline; Casoni, Elia; Mistri, MicheleMunari, Cristina; Scoponi, Marco; Sfriso, Andrea A.; Sfriso, Adriano; Aiello, Jacqueline; Casoni, Elia; Mistri, Michel

Multiannual Trend of Micro-Pollutants in Sediments and Benthic Community Response in a Mediterranean Lagoon (Sacca di Goro, Italy)

none6noLong-term variations of ecological status in a Mediterranean coastal lagoon (Sacca di Goro, Northern Adriatic) were investigated, combining data on the concentration of surface sediment contaminants and on the structure of the macrobenthic community. The aim was to assess any amount of chemical contamination and check the response of the macrobenthic community to sediment contamination. Over the studied period, the sediments of the lagoon showed contamination by trace metals and organochlorine pesticides, with most of them exceeding the thresholds indicated by the Italian legislation in many samples. Contamination by polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) instead never exceeded the threshold. The ecological status based on the macrobenthic community, evaluated through biotic indices (AMBI and M-AMBI), fell below the Good/Moderate threshold in most samples. The results indicate a possible influence of toxic compounds in sediment on benthic organisms, but most of the variability shown by the macrobenthic community is probably due to other factors. The difficulty in establishing a cause/effect relationship was due to the co-occurrence and variability of various stressors (both natural and anthropogenic) and their interactions. The methods currently used for monitoring transitional waters thus seem insufficient to disentangle the effect of pollutants and other environmental variables on the benthos. Integrated approaches (e.g., bioaccumulation and toxicity tests) are thus needed for a more precise identification of the risk posed by a high concentration of pollutants in such environmentsopenPitacco, Valentina; Mistri, Michele; Ferrari, Carla Rita; Sfriso, Adriano; Sfriso, Andrea Augusto; Munari, CristinaPitacco, Valentina; Mistri, Michele; Ferrari, Carla Rita; Sfriso, Adriano; Sfriso, Andrea Augusto; Munari, Cristin

In situ biomass production of Gracilariaceae and Ulva rigida: The Venice Lagoon as study case.

The growth and biomass production of the most abundant Gracilariaceae: Gracilariopsis longissima (S.G. Gmelin) M. Steentoft, L.M. Irvine et W.F. Farnham, Gracilaria gracilis (Stackhouse) M. Steentoft, L.M. Irvine et W.F.Farnham and Gracilaria vermiculophylla (Ohmi) Papenfuss, and of Ulva rigida C. Agardh were studied during 1 year in two areas of the Venice Lagoon, namely Tresse and San Giuliano, that were characterized by different trophic levels and water turbidity. Both growth and macroalgal production were monitored every 7–11 days in cubical cages placed on the bottom within the natural biomass. Environmental parameters, nutrient concentrations in the water column and surface sediments, and sedimentation rates were also determined. The biomass production of the two stations was very different and strongly influenced by the water turbidity and sedimentation rates. In both areas the availability of nutrients were high, but Tresse, where waters were more transparent, was more productive. In that area, the annual production of Gracilariaceae ranged between 21.9 and 28.2 kg fresh weight (fw) m−2 and G. longissima was the most productive species. Ulva production was within the same range (25.8 kg fw m−2). The mean relative growth rates on an annual basis were between 1.87 and 2.41% day−1. In contrast, in the turbid area (San Giuliano), the annual production of Gracilariaceae was much lower, ranging from 9.0 to 12.8 kg fw m−2 and that of Ulva was 15.2 kg fw m−2