Luciano Masiero

Hidden secrets of the Northern Adriatic: “Tegnúe”, peculiar reefs

Research carried out over the last 40 years has underlined the scientific importance of the rocky outcrops scattered on the Northern Adriatic Sea bed sometimes referred to as “tegnúe”. The zoobenthic biocenoses developing over these peculiar geological formations are as extraordinary as they are unique. A study carried out for an entire year in two sampling stations, at different distances from the coast, revealed a very high number of zoobenthic species, including those which have now become rare and are therefore protected in Italian seas. The water turbidity of the northern Adriatic Sea greatly reduces the quantity of light reaching these outcrops, limiting the activity of autotrophic organisms only to sciaphilous genera. Thus, the most represented trophic categories of zoobenthos are suspension, especially filter feeders. Biodiversity values calculated for the communities of these particular reefs are far higher than normally found in the soft seabed in nearby areas, but even higher than in other coralligenous outcrops in other marine ecosystem in the world. The ecological role played by the tegnúe in the Northern Adriatic is extraordinary because as well as being true oases of biodiversity, they are areas naturally protected against bottom trawl-fishing. Thus, they offer shelter and reproduction sites for a number of fish and invertebrate species, including some under stress due to severe fishing pressure.

Ecological, physiological, and biomolecular surveys on microalgae from Ross Sea (Antarctica)

Abstract Results of analyses on pico, nano‐ and microphytoplankton from the sea‐ice of Terra Nova Bay, during austral summer 1995–96, are reported. In this environment, among the 116 taxa that we found, the most abundant were diatoms (102). The interior algal community of the sea‐ice was dominated by Fragilariopsis spp., Archeomonas areolata, and hypnozygotes of Porella glacialis. In the algal mat at the deeper layer of the ice, however, diatoms showed higher density. Photoautotrophic picoplankton was also present and red‐fluorescing cells, small eukaryotes and phycocyanin‐rich cyanobacteria prevailed over phycoerythrin‐rich cyanobacteria. Besides these data, ultrastructural, physiological and biomolecular surveys on three Antarctic sea water microalgae, of which only Koliella antarctica was known, were also carried out. The 18S rDNA gene sequences of K. antarctica and other closely related species allowed us to verify that the Koliella genus belongs to Trebouxiophyceae, while as regards the other two taxa, one of them was found to belong to the Heterococcus and the other to the Pyramimonas genus. They might be unde‐scribed species of the Southern Ocean. Pyramimonas sp., found in Terra Nova Bay during the austral summer 1998–99, carried tri‐chocysts. Moreover, K. antartica, like Heterococcus sp., showed great ability to live both in fresh water and at different salinities.

Influence of temperature on fluoride toxicity and bioaccumulation in the nonindigenous freshwater mollusk Dreissena polymorpha Pallas, 1769

Fluoride toxicity and bioaccumulation tests (short- and long-term) were performed on the nonindigenous freshwater mollusk Dreissena polymorpha at two different temperatures: 17 ± 0.5°C and 22 ± 0.5°C. Concentrations that did not result in toxicity in short-term experiments (96 h) induced effects over a longer period (17 weeks), especially at the warmest temperature, highlighting the role of this parameter. Fluoride bioaccumulation increased linearly with increasing concentration and temperature, reaching 4,202 µg F(-)/g dry weight in soft tissues only after 48 h of exposure at 22°C at a concentration of 640 mg F(-)/L. Comparing tolerance to fluoride and bioaccumulation values of this species with those of other freshwater invertebrates, D. polymorpha was much more resistant and revealed its capacity to accumulate a great quantity of this xenobiotic substance. The results of the present study demonstrated that fluoride accumulation in the soft tissue of this animal was much higher (up to 1,409.6 µg F(-)/g dry wt) than that in its shell (up to 706.4 µg F(-)/g dry wt). If we consider this datum and the fact that D. polymorpha is widespread in many aquatic ecosystems around the world, representing a food source for many birds and other vertebrates, we must acknowledge the possibility that it can represent a serious danger in view of fluoride biomagnification in the aquatic environment.

Phytoplankton and chemico-physical parameters of the Scardovari Lagoon (Po Delta, North Adriatic Sea) during 1991 and 1992.

Abstract During research directed towards the employment of the biological resources of the North Adriatic lagoons, from January 1991 to December 1992, in both tidal phases, a survey was carried out on the phytoplankton and the chemico-physical parameters of the Scardovari lagoon. Data analyses allowed two different areas to be distinguished: one inner, which was generally characterized by high phytoplanktonic densities (St. 3–4), the other outer, which was more influced by marine load (St. 1–2). Photosynthetic picoplankton was dominant in terms of cell number in most samples. Phytoplanktonic fraction >2 μm was represented mainly by diatoms, which showed the higher species number. During the sample observation, some dinoflagellates, considered toxic or potentially toxic, were found. Their presence was important because of their effect on the bivalve mollusc cultures.

Effects of aminomethylphosphonic acid, the main breakdown product of glyphosate, on cellular and biochemical parameters of the mussel Mytilus galloprovincialis

Abstract The effects of the breakdown products of herbicides on aquatic species are largely unknown. In a recent study, we evaluated the effects of glyphosate on the mussel Mytilus galloprovincialis. This study was designed to evaluate for the first time the impact of aminomethylphosphonic acid (AMPA) ‐ the main breakdown product of glyphosate ‐ on cellular and biochemical parameters of the mussel Mytilus galloprovincialis. Bivalves were exposed for 7, 14 and 21 days to 1, 10 and 100 &mgr;g/L of AMPA and various biomarkers were measured in haemolymph (total haemocyte counts, haemocyte diameter and volume, haemolymph pH, haemocyte proliferation, haemolymph lactate dehydrogenase activity, haemocyte lysate lysozyme and acid phosphatase activities), as well as in gills and digestive gland (superoxide dismutase, catalase, glutathione S‐transferase and acetylcholinesterase activities). AMPA concentrations in seawater samples from the experimental tanks were also measured in order to correlate the biomarker responses of mussels with their exposure to the actual concentrations of AMPA. The MANOVA analysis demonstrated that the experimental variables considered (exposure dose, exposure duration, and their interaction) affected significantly biomarker responses. Nevertheless, the two‐way ANOVA analysis revealed significant effects of AMPA on most of the biomarkers measured. The overall results of this study demonstrated that AMPA can affect cellular and biochemical parameters in mussels, similarly to glyphosate. Graphical abstract Figure. No Caption available. HighlightsMussels were exposed to various AMPA concentrations.AMPA affected mostly haemocyte parameters.AMPA did not affect significantly antioxidant enzymes.AMPA generally increased AChE activity in gills.