Microplastics are widespread in the aquatic environment and thus available for many organisms at different trophic levels. Many scientific papers focus their attention on the study of the effects of ...microplastics on different species at individual level. Here we performed a global scale meta-analysis focusing our work on the study of the effect of microplastics on the functional traits of aquatic benthic organisms. Overall, microplastics showed a moderate negative effect on the examined functional traits of benthic organisms. Our results show that some crucial functional traits, such as those linked to behaviour and feeding, appear to be unaffected by microplastics. In contrast, traits related to the capacity of organisms to assimilate energy are affected. Moreover, traits with possible effects at population level appear to be negatively affected by microplastics. We discuss how the direct impact of organismal performance may have indirect repercussions at higher levels in the ecological hierarchy and represent a risk for the stability and functioning of the ecosystem.
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•We collated and synthetised scientific evidence of microplastics effects on benthos.•The meta-analysis focused on functional traits of benthic species of aquatic realms.•Microplastics showed a moderate negative effect on the examined functional traits.•Quantitative synthesis represents a robust, salient, integrated scientific baseline.•Results can inform scientists, stakeholders addressing the decision-making process.
Our quantitative synthesis on the effects of microplastics on functional traits of benthic species inhabiting aquatic habitats represents a potential step forward from the existing literature focused on plastics occurrence monitoring only.
The use of rigorous methodologies to assess environmental, social and health impacts of specific interventions is crucial to disentangle the various components of environmental questions and to ...inform public opinion. The power of systematic maps relies on the capacity to summarise and organise the areas or relationships most studied, and to highlight key gaps in the evidence base. The recent Italian technical referendum (2016) – a public consultation inviting people to express their opinion by voting to change the rules on the length of licence duration and the decommissioning of offshore oil and gas platform drilling licences – inspired the creation of a systematic map of evidence to scope and quantify the effects of off-shore extraction platforms on Mediterranean marine ecosystems. The map was aimed as a useful model to standardise a “minimal informational threshold”, which can inform public opinion at the beginning of any public consultation. Produced by synthesising scientific information, the map represents a reliable layer for any future sustainable strategy in the Mediterranean basin by: (i) providing a summary of the effects of marine gas and oil platforms on the Mediterranean marine ecosystem, (ii) describing the best known affected components on which the biggest monitoring efforts have been focused, and (iii) strengthening the science-policy nexus by offering a credible, salient and legitimate knowledge baseline to both public opinion and decision-makers. The map exercise highlights the knowledge gaps that need filling and taking into due consideration before future transnational and cross-border monitoring and management plans and activities can be addressed.
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•We developed a systematic map (SM) as a useful model to standardise a “minimal informational threshold”.•SM allowed to scope and summarise the existing evidence on the effects of off-shore extraction platforms on the Mediterranean marine ecosystem.•SM will represent a useful layer for future sustainable strategies.•SM allows to grasp the effects on the ecosystem health, depict the most affected components, inform the public opinion.•SM highlights knowledge gaps to fill to address the future transnational and cross-border monitoring and management plans.
Grasping the effects of marine extraction platforms on the Mediterranean marine ecosystem to inform public opinion and address future monitoring and management plans.
Temperature increases, hypoxia, and changes in food availability are predicted to occur in the future. There is growing concern for the health status of wild and farmed organisms, since environmental ...stressors alter organism functions, and elicit coordinated physiological responses for homeostasis. Mussels are good bioindicators of environmental conditions. Their ability to maintain unaltered immunosurveillance under adverse environmental conditions may enhance their survival capability. Few studies are currently concerned with the relationships and feedback among multiple stressors. Here, food concentration, temperature, and oxygenation treatments were evaluated for their effects on immune enzymatic parameters of
Mytilus galloprovincialis
detected in the digestive gland and the lysosomal viability by neutral red uptake. Mussels were exposed to three temperatures (12, 20, and 28 °C) under normoxic (8 mg O
2
l
−1
) and anoxic conditions and specimens were fed with six food concentrations, ranging 0.2–5 g chlorophyll l
−1
. Temperature increases affected esterase and alkaline phophatase enzyme functionality, and addition of food buffered detrimental effects generated by harsh conditions, such as those provided by low oxygen concentrations. Kinetics of the phenoloxidase was negatively correlated with increasing temperature. In this case, food had a buffering effect that counteracted the limiting temperature only under normoxic conditions. In addition, the stability of the lysosomal membrane was altered under conditions of thermal stress and food change, under normoxic and anoxic conditions. Overall, environmental stress factors affected immune biomarkers of Mediterranean mussels, and the level of food acted as a buffer, increasing the thermal resistance of the specimens.
Habitat complexity is one of the main influences on biodiversity in marine environments, particularly in coastal areas where foundation seaweeds provide substrate for highly diverse communities. We ...studied the 2D and 3D fractal dimensions of Gongolaria montagnei (Fucales) over the vegetative season and examine their relationship with the abundance, species richness and morpho-functional groups of the gastropod associated. Overall, the 3D fractal analysis method used here better describes seaweeds structural complexity compared to the traditional 2D fractal analysis, as highlighted by the higher relationship with gastropod assemblage associated to the alga in terms of abundance, number of species and morpho-functional groups. We propose this new method as a valuable tool for understanding the relationship between seaweeds and associated fauna, which is critical for gaining a better understanding of the role that algal species play in a specific habitat and the consequences of their loss.
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•The 3D fractal dimension used here closely reflects the complexity of seaweeds.•The 3D fractal dimension explained better variation of gastropods.•Seaweeds complexity plays a main role in shaping associated gastropods assemblage.•The morpho-functional groups of gastropods clarify the relationship between seaweed and gastropods.
Microplastics represent an ever-increasing threat to aquatic organisms. We merged data from two global scale meta-analyses investigating the effect of microplastics on benthic organisms' and fishes' ...functional traits. Results were compared, allowing differences related to vertebrate and invertebrate habitat, life stage, trophic level, and experimental design to be explored. Functional traits of aquatic organisms were negatively affected. Metabolism, growth, and reproduction of benthic organisms were impacted, and fish behaviour was significantly affected. Responses differed by trophic level, suggesting negative effects on trophic interactions and energy transfer through the trophic web. The experimental design was found to have the most significant impact on results. As microplastics impact an organism's performance, this causes indirect repercussions further up the ecological hierarchy on the ecosystem's stability and functioning, and its associated goods and services are at risk. Standardized methods to generate salient targets and indicators are urgently needed to better inform policy makers and guide mitigation plans.
Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its reduction has been included in national and international regulations. Despite the fact that many ...studies have pointed out the ecological impact of noise on marine organisms, few studies have investigated - in a field context - the behavioral response to boat noise in fish. In the present study we measure how Sciaena umbra reacts to boat noise. We found that boat noise: i) increased duration of flight reactions and number of individuals performing them, ii) increased the frequency of hiding behaviors, and iii) did not elicit a change in fish activity level and sound emission. Flights and hiding behavior, usually related to predation risk, were not uniform between individuals and showed a quick recovery after noise exposure. On the basis of these results, potential metabolic, physiological and behavioral consequences are discussed and management recommendations are proposed.
•Sciaena umbra showed no changes in activity levels as a consequence of boat noise.•No change in sound emission frequency as a consequence of noise exposure was found.•S. umbra showed increased flight and hiding behavior as a response to boat noise.•The present study highlighted a different individual response to high noise level.
•We measure the effectiveness of marine park management on conservation of seagrass.•Mooring fields and anchoring restrictions are not efficient system in protecting seagrass.•The condition of P. ...oceanica is disturbed both in mooring fields and in control area.•Anchor scars increase after the tourist season.•Traditional mooring systems have impact on the surrounding area of the meadow.
Posidonia oceanica (L.) Delile meadows are recognized as priority habitat for conservation by the EU Habitats Directive. The La Maddalena Archipelago National Park (Mediterranean Sea) P. oceanica meadow, the dominant coastal habitat of the area, is mostly threatened by boat anchoring. 12years after the establishment of mooring fields and anchoring restrictions, a study was conducted to measure their effectiveness on the conservation of seagrass and the mitigation of anchoring damage. We found that: (i) the condition of P. oceanica was disturbed, both in the mooring fields and in control locations; (ii) mooring fields and anchoring restrictions did not show to be an efficient system for the protection of seagrass, in fact anchor scars increased after the tourist season; (iii) the mooring systems had an impact on the surrounding area of the meadow, probably due to their misuse. On the basis of these results, management recommendations for marine parks are proposed.
Anthropogenic pressure adds up and interacts with the effects of climate change with a varying magnitude and potential changes depend on species’ Life History (LH) traits, local environmental ...conditions and co-occurrence of several stressors. Stressors exert negative effects on marine biota when acting as a single factor, but the effects may be amplified when more than one stressor work in combination, producing interacting effects on biodiversity and ecosystem functioning. The impairment of individual functional traits (FT) leads to strong rebounds on LH traits and this may have ecological consequences. No studies actually relate FT and antioxidant enzymes to multiple environmental stressors. In this paper we investigate the effects of food concentration, temperature and hypoxia on metabolic traits as expressed by a proxy such as respiration rate and feeding behaviour and on antioxidant enzymes (Catalase, Superoxide dismutase, Glutathione S-Transferase, Glutathione peroxidase) for the bivalve Mytilus galloprovincialis. Mussels were exposed to three temperatures (12, 20 and 28 °C) under normoxic (8 mg O2 l−1) and hypoxic (~2 mg O2 l−1) conditions, with varying food concentrations ranging from 0.9 to 3.5 μg of chlorophyll l−1. The results show that FTs and antioxidant enzymes were affected by temperature, hypoxia and food availability, and outcome allowed us to emphasise that a multi-scalar integrated approach is suitable to detect and monitor effects of anthropogenic disturbance on ecosystem functioning.
•Functional traits are impaired by anthropogenic stressors.•Temperature and hypoxia affect metabolism and antioxidants in blue mussel.•A multi-scalar approach detects effects of disturbance on ecosystem functioning.
A current practice of marine aquaculture is to integrate fish with low-trophic-level organisms (e.g. molluscs and/or algae) during farming to minimise effects of cultivation on the surrounding ...environment and to potentially increase economic income. This hypothesis has been tested in the present article experimentally, by co-cultivating fish and mussels (Mytilus galloprovincialis) in the field. Integrated multi-trophic aquaculture (IMTA) experiments were started in July 2004 by transplanting mussel seed at two depths (−3 and −9 m) within 1,000 m downstream to fish cages and at 1,000 m upstream from cages. Mussels were cultured in nylon net bags for 12 months and the growth recorded biometrically. The outcome of our field experiment corroborated the idea of IMTA effectiveness. In fact, in the study area, the organic matter from fish-farm biodeposition caused changes in the chemical environment (i.e. controls and impacted sites were significantly different for organic matter availability and chlorophyll-a) and this induced changes in growth performance of co-cultivated mussels. Mussels cultivated close to cages, under direct organic emission, reached a higher total length, weight and biomass than mussel cultivated far from farms.
Possible changes in diet and trophic levels in relation to size of Mediterranean bluefin tuna, Thunnus thynnus, were investigated using labelled carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotopes. ...Samples were obtained from two locations in the southern Tyrrhenian Sea (Western Mediterranean Sea) in May and October 2004. The δ¹³C and δ¹⁵N analyses revealed at least three significant isotopic groups small juveniles (0.7-2.2 kg), sub-adults (15-50 kg) and adults (70 to 225 kg). δ¹³C was negatively dependent on weight, while δ¹⁵N was positively dependent on weight TW = 8.2 (±0.16) + 0.03 (± 0.0) *δ¹⁵N (n = 49; r = 0.91; P < 0.001). Different prey contribution to the diet was highlighted for each class. The diet of juveniles comprised zooplankton, small pelagic fish and some coastal fish; sub-adults relied on medium pelagic fish, shrimps and cephalopods, and adults relied mainly on cephalopods and larger fish. The trophic level (TL) of tunas belonging to each size class was closely correlated to weight, starting from ca 3.0 TL for Group I and reaching 4.4-4.8 TL for the giants. Bluefin tuna, from small juveniles to giants, showed a shift in feeding preferences due to different use of habitats and food items as a function of the life stage.
