Transgenerational effects and phenotypic plasticity in sperm and larvae of the sea urchin Paracentrotus lividus under ocean acidification.

In marine organisms, differing degree of sensitivity to ocean acidification (OA) is expected for each life stage, and disturbance at one stage can carry over into the following stage or following generation. In this study we investigated phenotypic changes of sperm and larvae of the sea urchin Paracentrotus lividus in response to different pH conditions (8.0, 7.7, 7.4) experienced by the parents during gametogenesis. In sperm from two-months exposed males, sperm motility, velocity, ATP content, ATP consumption and respiration rate were evaluated at three pH values of the activating medium (8.0, 7.7 and 7.4). Moreover, larvae from each parental group were reared at pH 8.0 and 7.7 for 20 days and larval mortality and growth were then assessed. Sperm motility and respiration rate were not affected either by exposure of males to low pH or by the post-activation pH. Sperm velocity did not differ among post-activation pH values in all sperm groups, but it decreased slower in sperm developed under acidified conditions, suggesting the presence of positive carryover effect on sperm longevity. This positive carryover effect of exposure of males to low pH values was highlighted also for the sperm ATP content, which was higher in these groups of sperm. ATP consumption rate was affected by post-activation pH with higher values at pH 8.0 in sperm from males maintained at control condition and pH 7.7 while the energy consumption appeared to be differently modulated at different experimental conditions. A negative carry over effect of OA was observed on survival of larvae from parents acclimated at pH 7.4 and additive negative effects of both parental and larval exposure to low pH can be suggested. In all groups of larvae, decreased somatic growth was observed at low rearing pH, thus larvae from parents maintained at low pH did not show an increased capability to cope with OA.

Do males and females respond differently to ocean acidification? An experimental study with the sea urchin Paracentrotus lividus.

Seawater pH lowering, known as ocean acidification, is considered among the major threats to marine environment. In this study, post-spawning adults of the sea urchin Paracentrotus lividus were maintained at three pH values (8.0, 7.7, 7.4) for 60 days. Physiological, biochemical, cellular, behavioural and reproductive responses were evaluated in males and females. Significant differences between sexes were observed, with higher ammonia excretion and lower catalase activity in males. Respiration rate (after 21 days), catalase activity in gonads and total coelomocyte count showed the same increasing trend in males and females under low pH. Ammonia excretion, gonadosomatic index and lysozyme activity exhibited opposite responses to low pH, with an increasing trend in males and decreasing in females. Results demonstrated that exposure to low pH could result in different response strategies of male and female sea urchins at a physiological, biochemical and immunological level. Reduced female gonadosomatic index under low pH suggested decreased energy investment in reproduction.

First evaluation of floating microplastics in the Northwestern Adriatic Sea.

Plastic pollution in the marine environment is becoming a problem of global concern, and the Mediterranean is believed to be one of the worst affected regional seas. The present study presents data on floating microplastics in the Northwestern Adriatic Sea in order to evaluate the possible contribution of two significant potential sources: the lagoon of Venice and the Po River. Samples were collected in March and April 2014 along two transects located off Pellestrina Island (Venice) and the Po Delta, each consisting of four sampling stations at 0.5, 3, 10, and 20 km from the shoreline. Microplastics were quantified and classified according to their colors and shapes and analyzed by micro-attenuated total reflection-FT-IR. Microplastics were found in all samples, albeit with high spatial and temporal variability. The highest concentrations were observed in March at the offshore station of the Pellestrina transect (10.4 particles m-2) and the two landward stations off the Po Delta (2.1 and 4.3 particles m-2), highlighting the influence of various factors, such as surface circulation and river discharges, in determining specific accumulation patterns. The most common polymers were polyethylene and polypropylene, and most of the particles were secondary microplastics (83.5%). The patchy distribution of microplastics observed in the study area is driven by hydrodynamic and meteorological factors acting on short time scales.

A first survey on the biochemical composition of egg yolk and lysozyme-like activity of egg envelopment in the cuttlefish Sepia officinalis from the Northern Adriatic Sea (Italy).

The cuttlefish Sepia officinalis is an important fishery resource in the Northern Adriatic Sea (Italy). During reproduction, fertilised eggs are released by adult females in coastal waters and embryo development can take over two months. During this period, embryos rely on nutrients and other substances, such as immune factors, provided by the female in egg yolk. In cephalopods in general, and specifically in the common cuttlefish, little information is available on yolk biochemical composition and substances included in egg envelopment. In the present study, the main biochemical components of egg yolk and the presence of antimicrobial substances in egg envelopment of S. officinalis were determined for the first time. Statistically significant differences in total egg weight and egg yolk weight were observed among batches from different females. Egg and yolk weights were positively correlated, with yolk representing the 13% (±5%) of the total egg weight. Total proteins were the main biochemical component (46%) of egg yolk, followed by total carbohydrates plus glycogen (39%) and lipids (15%). Statistically significant differences among batches were recorded in egg yolk total protein amounts, lipids, carbohydrates and glycogen, but no correlations were found between egg yolk weight and the biochemical components. The Petri dish and the quantitative spectrophotometric assays revealed the presence of lysozyme-like activity in egg gelatinous envelopment.