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Marine litter in stomach content of small pelagic fishes from the Adriatic Sea: sardines (Sardina pilchardus) and anchovies (Engraulis encrasicolus)

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Marine litter impacts oceans and affects marine organisms, representing a potential threat for natural stocks of pelagic fish species located at the first levels of the marine food webs. In 2013–2014, on a seasonal basis, marine litter and microplastics in stomach contents from Sardinia pilchardus and Engraulis encrasicolus were evaluated. Selected species are plankitivores of great ecological and commercial importance in the Adriatic Sea. Collected data were correlated to possible factors able to affect ingested levels as well as species, season of sampling, biometry and sex of animals. Almost all tested samples (80 organisms for each species) contained marine litter (over 90% of samples from both species) and also microplastics; while any meso- or macroplastics were recorded. On average, recorded items were as follows: 4.63 (S. plichardus) and 1.25 (E. encrasicolus) per individual. Sardines evidenced a higher number of microplastics characterised by a smaller size than those recorded in anchovies. For sardines, sex, Gastro Somatic Index and sampling season showed negligible effects on the number of ingested litter; conversely, anchovies showed differences related with both sex of animals and dominant colour of ingested materials with prevalence for black and blue colours.
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Monia Renzi
&Antonietta Specchiulli
&Andrea Blašković
&Cristina Manzo
&Giorgio Mancinelli
Lucrezia Cilenti
Received: 1 June 2018 /Accepted: 13 November 2018 /Published online: 27 November 2018
#Springer-Verlag GmbH Germany, part of Springer Nature 2018
Marine litter impacts oceans and affects marine organisms, representing a potential threat for natural stocks of pelagic fish species
located at the first levels of the marine food webs. In 20132014, on a seasonal basis, marine litter and microplastics in stomach
contents from Sardinia pilchardus and Engraulis encrasicolus were evaluated. Selected species are plankitivores of great ecological
and commercial importance in the Adriatic Sea. Collected data were correlated to possible factors able to affect ingested levels as well
as species, season of sampling, biometry and sex of animals. Almost all tested samples (80 organisms for each species) contained
marine litter (over 90% of samples from both species) and also microplastics; while any meso- or macroplastics were recorded. On
average, recorded items were as follows: 4.63 (S. plichardus) and 1.25 (E. encrasicolus) per individual. Sardines evidenced a higher
number of microplastics characterised by a smaller size than those recorded in anchovies.For sardines, sex, Gastro Somatic Index and
sampling season showed negligible effects on the number of ingested litter; conversely, anchovies showed differences related with
both sex of animals and dominant colour of ingested materials with prevalence for black and blue colours.
Keywords Marine litter .Microplastic .Plastic ingestion .Stomach content .Edible fish species .Human consumption
Global production of plastics has been growing for more than
50 years, reaching 300 million tonnes in 2013, with a 3.9%
increase compared to that in 2012 (Plastic Europe 2014). By
2014, the rate of global production had reached 311 million
tonnes per year and the long-term forecasts suggest that by
2050 annual global production shall be between 850 million
tonnes and 1124 million tonnes (Crawford and Quinn 2016).
Due to its large use, scarce biodegradability and growing in-
puts, a huge quantity of plastic is accumulating in marine
environments (Thompson et al. 2009; Law et al. 2010;
UNEP 2014), leading to a growing concern for the conserva-
tion of marine ecosystem (Barnes et al. 2009). Indeed,
BMarine Litter^was introduced by the Marine Strategy
Framework Directive (MSFD - Directive 2008/56/EC) as one
of the 11 descriptors to define marine ecosystemsenvironmen-
tal status and to target the BGood Environmental Status^in
2020 (Galgani et al. 2013). The greatest alarm is raised by the
accumulation of large quantities of very small pieces of plastic
litter (< 5 mm in diameter), known as microplastics (MPs), in
marine organisms (Collard et al. 2017a and references therein).
MPs could represent a threat for the integrity of marine ecosys-
tems as well as for their conservation, due to their ability to
absorb chemicals from water (Browne et al. 2013), to release
harmful chemicals in the environment (Lee et al. 2018)andto
be a vector for allochthonous microorganism diffusion in high-
value marine ecosystems (Zettler et al. 2013). Recent
studies have shown that MPs are ingested by a large number
of marine organisms (Avio et al. 2015;Collardetal.2017b;
Dehaut et al. 2016; Fossi et al. 2016), penetrating the marine
Responsible editor: Philippe Garrigues
*Monia Renzi
Bioscience Research Center, Via Aurelia Vecchia 32,
58015 Orbetello, Grosseto, Italy
Department of Lesina (FG), National Research Council - Institute for
Biological Resources and Marine Biotechnologies Marine Science,
Via Pola 4, 71010 Lesina, Foggia, Italy
Department of Biological and Environmental Sciences and
Technologies, University of the Salento, Lecce, Italy
CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze del
Mare, Piazzale Flaminio, 4, 00196 Rome, Italy
Environmental Science and Pollution Research (2019) 26:27712781
Marine litter in stomach content of small pelagic fishes from the Adriatic
Sea: sardines (Sardina pilchardus) and anchovies
(Engraulis encrasicolus)
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Dissection equipments were cleaned with prefiltered distilled water before and after handling each specimen. When the dissection procedure was completed for all specimens, for each gram of digested organ 20 mL of 30 % H 2 O 2 were added into a glass beaker (Renzi et al., 2019). Then, solution was kept on a hot plate at 60 • C until the soft tissues were completely digested which takes approximately 12 h . ...
This study provides the first evidence of microplastic (MP) occurrence in gill and gastrointestinal tract (GIT) of Pontastacus leptodactylus (N = 37), a commercially important crayfish in Turkey. MPs were found in the GIT of all examined individuals with an average of about 11.9 ± 9.7 (male: 13.6 ± 8.3 and female: 10.1 ± 10.9) MPs/ind. Female crayfishes ingested less MPs than males potentially due to being more sedentary as well as interruption in feeding during spawning and hatching periods. The concurrencies of tangled balls of fibers were detected as 47 % in males and 28 % in females. The majority of extracted microplastic were fiber (97 %), black (56 % in the gill and 38 % in the GIT) and 1-2.5 mm in size (35 % in the gill and 39 % in the GIT). High MPs contamination observed in this study highlights the concerns related to the consumption of seafood since Pontastacus lep-todactylus is commercially used.
In recent years it has been stressed that the problems created by population growth and climate change are so big and of such complexity that we do not have the capacity to address them. We do not react to a cascade of situations that are driving us to absolute collapse for two reasons: (1) The mental short-termism that is inherent in any animal, including the human being, (2) the synergy of factors that act together, not being able to isolate each other to give partial solutions. In this puzzle, the oceans, after decades of being ignored, seem to take on rele�vance. The UN launched a plan to draw attention to the role of that 70% mass of water that covers the surface of our planet, finally coming to the conclusion that part of the solution lies in understanding, managing and restoring the oceans. Biodi�versity, complexity, and functionality take on relevance in one of the Sustainable Development Goals that aims to improve our oceans. Life Below Water (SDG 14) is one of the goals to be achieved in this desperate decade, in which we are going to have to race to try to save civilization in its many facets. A Decade of the Oceans has been instituted that aims to channel the greatest possible number of initiatives to substantially improve the health of marine habitats, as well as try to mitigate the impact on human communities. Fisheries, pollution, and urban expansion are some direct issues that are stressing the oceans, but we may have direct (local and regional) solutions to solve them in many cases. However, among all the challenges we face, the most global and complex one to mitigate is climate change. In the oceans, climate change is especially evident, since 93% of the heat absorbed by the earth is concentrated in the water masses that are warming rapidly. Acidification, which is the sister of warming in water masses due to the increase in CO2 that penetrates and reacts to create slightly less alkaline water, is the other large-scale problem that has a global impact and cannot be controlled locally. Marine organisms suffer these consequences, having to adapt, migrate or disappear. We have created a transition phase to a new unknown state in which some species, habitats and even biomes will prevail while others languish or simply disappear. Understanding, managing and repairing our actions in the oceans has become a very urgent task to solve the problem and understand how long this transition between systems will last. This book focuses, in seven chapters, on the perspectives and solutions that different research groups offer to try to address problems related to SDG 14: Life Below Water. The different objectives developed in SDG 14 are treated indepen�dently, with an attempt to give a global vision of the issues. The mechanism used to select the book’s content was through an Artificial Intelligence program, choosing articles related to the topics by means of keywords. The program selected those arti�cles, and those that were not related to the topic or did not focus on SDG 14 were discarded. Obviously, the selection was partial and the entire subject is not covered, but the final product gives a very solid idea of how to orient ourselves to delve deeper into the topic of SDG 14 using published chapters and articles. The AI program itself selected the text of these contributions to show the progress in different topics related to SDG 14. This mode of operation will allow specialists (and non-specialists) to collect useful information for their specific research purposes in a short period of time. At a time when information is essential in order to move quickly by providing concrete answers to complex problems, this type of approach will become essential for researchers, especially for a subject as vast as SDG 14.
It is not surprising that we are interested in plastics as one of the most prominent polluting agents of the twenty-first century. We have gone from producing less than 10 million tons in the 1960s to more than 300 million in the 2010s. That plastic has had time to distribute itself, fragment and enter food chains of the oceans. Studies related to the three phenomena are now one of the main objectives of various research projects and groups around the planet. The first is understanding how fragmentation is increasing the volume of macro and microplastics, how they are dispersed at the oceanic and local level, and what their chemical characteristics are. In line with these observations and quantifications, we have to understand what influence they have on organisms and how we can reduce their concentration. For example, the displacements of macroplastics are modeled relative to their dispersion according to global and local currents, giving importance to the phenomena of fouling and fragmentation, as well as understanding how the creation of microplastics is heterogeneous according to latitude, water temperatures or seasonal conditions. One of the biggest problems is, without a doubt, the chemical, morphological and size classification of plastics, especially micro and nanoplastics. This topic is crucial, as is the standardization of the measures that we consider to classify them in one way or another. This topic has been largely discussed during the last decade, and in this chapter there are cues to understand that the consensus is very close. Other issues are still pending in the complex agenda of the understanding of these pollutants. For example, the adherence of certain types of elements such as heavy metals is a relevant issue on which much information is lacking. But it is not the only knowledge gap that we have. Dynamics in the water column and in the sediment is also a main issue, since this sediment is a sink for microplastics and nanoplastics that is continually disturbed by organisms from the meiofauna. Some of these microplastics become airborne, and their range from likely emission sources is still poorly understood. The understanding of these fluxes from the land-river to the sediments passing through the water column is one of the main challenges to solve the problems derived from the presence of such macro, micro and nano items. Marine organisms are the ones that, apparently, are the most affected by this increase in solid contamination, especially microplastics. Today they are found at any latitude, from the poles to the equator, even in places as surprising as sea ice or abyssal depths. In fact, microplastics are found in very remote places, interfering with the diet of various planktonic and benthic organisms. There are many questions to be resolved, among others, how temperature affects the retention of microplastics in organisms, or which are the most vulnerable species. And we have to understand one important issue: many of those marine organisms affected by micro and nano plastics are part of our diet. Therefore, understanding the rate of transmission in food chains in general and in our consumption in particular is a major issue. That is why we looked for solutions, such as the use of bioremediators (active suspension feeders such as sponges, sea squirts, etc.) in areas where the abundance of microplastics is especially high. Bacteria are also beginning to be used as active decomposers of microplastics, a solution that could help eliminate a large amount of this material about which we still have too many knowledge gaps regarding the health of ecosystems and our own health. The synergy of efforts to understand all these different variables is crucial. During the next decade we do have to solve this plastic problem, with coordination, standardization and the application of different tools to execute the solutions of different associated problems.
Following the previous chapter about ecosystem conservation and restoration, we also need to strengthen the monitoring of climate change and biodiversity with the help of a plan that involves people outside the academic context. Citizen science has been shown to be a very good tool for providing useful data for scientists, if well directed. For example, the monitoring of invasive species is impossible to do from research institutes due to lack of money, tools and personnel. But well trained, even sporadic tourists can give useful information about their distribution. This is also true in the case of rare or endangered species, or in migrations or the detection of anomalies. They can also be useful in tracking marine litter, not only helping to clean beaches and seabed, but also observing the origin of that waste thanks to photos or collections that can be used to understand where the objects come from. Other observations and data collection are more complex, and require specialists to make adequate quantitative observations, but may still benefit from broad support from people who want to help in the logistical part. Once again, indigenous people are put in the spotlight, because they help to solve many problems thanks to their great local wisdom. We are realizing that many of the things we do to monitor and give keys for conservation are provided by local populations who have lived in, protected or managed the areas we want to study for hundreds of years or millennia. That is why it is important to accelerate the follow-up processes by broadening the spectrum of people who can help in these processes, professionals and non-professionals alike. However, there are limits. Specialist teams are still needed to do sampling, monitoring or experiments. The tools used by scientific research teams to make such monitoring programs have substantially advanced. The technology to keep track of the problems we have in the oceans has made a really important qualitative leap. For example, although attempts have been made to track oil spills in certain circumstances, only the collection of data by specialists can help to understand the origin of contaminants. Coastal and ocean governance needs a paradigm change. We need co-governance processes in which democratic decisions, education and awareness-raising fit together. The models in which people interact with science, problems and solutions about the oceans are more and more demanded, and the last two decades have been crucial. An authentic bottom-up process in which all these advances and the different ways of observing nature and the impacts suffered are available to non-specialists. Without that bridge, we will not be able to create the necessary conditions to reverse the process of deterioration of our oceans.
An important part of the health of the oceans depends on a good balance of the biogeochemical cycles. Both climate change (in its broadest sense, from the warming of the oceans to acidification) and the introduction of excess nutrients or heavy metals have caused, in many places, distortions in the balances between chemical elements, organisms and detritus. A series of scenarios have been created in which the excess or absence of certain components are distorting carbon fluxes or biomass accumulation. Such changes are not new at all, but now are accelerating and we have to be ready to understand and manage the repercussions that they may have locally and globally. An increase in nitrogen and phosphorus due to land changes in the Amazon, together with other local phenomena, are promoting an uncontrolled increase in Sargassum, which moves every year with the currents until it invades the Caribbean coast, for example. There is such inertia in the entry of these nutrients into the ocean that it becomes difficult to manage them, and even in areas where there is already a much more exhaustive control of the agricultural or industrial activities that promote them, the proliferation of micro and macro algae seems unstoppable. The microbial composition and also the seasonality are key points that have to be considered, especially when certain physical phenomena are weakened such as upwelling (and the related nutrient supply) or the ocean currents (and the related nutrient transport). Several models are based not only on temperature changes (which affect the availability of macro and micronutrients) but also on coastal morphology and local current dynamics. Such models are complex but very useful to understand, locally, what may happen with a cascade effect, such as the relationship of biogeochemical cycles with primary productivity and, in turn, with biomass production. Climate change is greatly affecting this nutrient availability, not only because the physical-chemical balance may be changing, but also because the organisms that process these nutrients are also changing and their ability to recycle may be affected. Acidification also enters this equation, which makes some microelements less available, or makes some species (for example, coccolithophorids) less capable of completing their life cycles, compete for nutrients or suffer more predation because they have more fragile structures. Latitude must also be taken into account in these changes, both due to the effects of climate change and the direct impacts of human activities that have profoundly transformed many ocean environments. In certain areas the predominance of the impact on biogeochemical cycle comes from the direct action of humans (e.g. fertilizers, farming, etc.), but in others the predominance comes from the warming or acidifying effect due to climate change. Thus, for example, the most accelerated changes in the Arctic are having very rapid effects on these biogeochemical cycles, both due to the increase in temperature and acidification and also due to the fact that the dynamics and coverage of the ice are changing. In this area, the direct impacts by pollution and eutrophication are replaced by climate change accelerating paths. Associated with these changes in nutrient cycles is the decrease in available oxygen that alters the physiological capacities of some organisms. The increase in temperature, the decrease in primary production and the slowdown in currents in various parts of the planet are affecting the response capacity of organisms, from benthic to pelagic. No less important is also the fact that stormy phenomena of different types are increasing in frequency and intensity. Storms and hurricanes are also responsible for the distortion of biogeochemical cycles, in some cases impoverishing biomass production and its quality for the following trophic levels. It is a very complex scenario in which the physiology and adaptability of many organisms is at stake, and which we will have to understand in order to properly manage marine resources in the near future.
Climate change, rigorously heralded more than thirty years ago as a real threat, has become the most pressing and pernicious global problem for the entire planet. In conjunction with local impacts such as fishing, eutrophication or the invasion of alien species, to give just a few examples, the acidification of the oceans and the warming of the sea began to show its effects more than twenty years ago. These signals were ignored at the time by the governing bodies and by the economic stakeholders, who now see how we must run to repair the huge inflicted damage. Today, different processes are accelerating, and the thermodynamic machine has definitely deteriorated. We see, for example, that the intensity and magnitude of hurricanes and typhoons has increased. Most models announce more devastation of flash floods and a decomposition in the water cycle, which are factors directly affecting ecosystems all over the world. Important advances are also observed in the forecasting of impacts of atmospheric phenomena in coastal areas with more and more accurate models. Rising temperatures and acidification already affect many organisms, impacting the entire food chain. All organisms, pelagic or benthic, will be affected directly or indirectly by climate change at all depths and in all the latitudes. The impact will be non-homogeneous. In certain areas it will be more drastic than in others, and the visualization of such impacts is already ongoing. Some things may be very evident, such as coral mortalities in tropical areas or in the surface waters of the Mediterranean, while others may be less visible, such as changes in microelement availability affecting plankton productivity. In fact, primary productivity in microalgae, macroalgae and phanerogams is already beginning to feel the impact of warmer, stratified and nutrient-poor waters in many parts of the planet. Nutrients are becoming less available, temperature is rising above certain tolerance limits and water movement (turbulence) may change in certain areas favoring certain species of microplankton instead of others. All these mechanisms, together with light availability (which, in principle, is not drastically changing except for the cloudiness), affect the growth of the organisms that can photosynthesize and produce oxygen and organic matter for the rest of the trophic chain. That shift in productivity completely changes the rest of the food chain. In the Arctic or Antarctic, the problem is slightly different. Life depends on the dynamics of ice that is subject to seasonal changes. But winter solidification and summer dissolution is undergoing profound changes, causing organisms that are adapted to that rhythm of ice change to be under pressure. The change is more evident in the North Pole, but is also visible in the South pole, where the sea ice cover has also dramatically changed. In the chapter there is also a mention about the general problem of the water currents and their profound change do greenhouse gas effects. The warming of the waters and their influence on the marine currents are also already affecting the different ocean habitats. The slowdown of certain processes is causing an acceleration in the deoxygenation of the deepest areas and therefore an impact on the fragile communities of cold corals that populate large areas of our planet. Many organisms will be affected in their dispersion and their ability to colonize new areas or maintain a connection between different populations. The rapid adaptations to these new changes are apparent. Nature is on its course of restart from these new changes, but in this transitional phase the complexity and interactions that have taken thousands or millions of years to form can fade away until a new normal is consolidated.
The impacts of industrial fishing have been present in the oceans for over one hundred years, but the exponential increase all over the world and the systematic exploitation of different areas started after world war II. The phenomenon of fishing has to be understood in order to understand the changes in the oceans, and such deep transformation is essential to capture the essence of the resilience: the collapse of fish stocks, the lack of biodiversity, and the profound transformation of ecosystems due to overfishing is in part responsible for the ocean’s impacted functioning that we witness today. It now seems that the collapse of many habitats is to blame for rising acidification or temperature, but the reality is that the impact of overfishing on pelagic and benthic systems is largely responsible for the profound transformations we see today. Trawling has devastated entire ecosystems, destroying the complexity of marine forests, both those that are dominated by vegetal organisms (macroalgae and phanerogams) and those dominated by animals (corals, gorgonians, sponges, etc.). It has been possible to verify that it is not only the destruction of the structures, but the compaction of the sediment and the continuous resuspension that made possible the impoverishment of the communities and therefore of the impoverishment of the fishing stocks. Beyond these impacts, pelagic fisheries have seen profound changes in populations, which evolve to the sound of fishing pressure. The minimum size of successful reproduction (i.e. the size in which the fish is lying eggs to promote the continuity of the populations), for example, has been drastically changed in many species, making possible for populations to survive despite the immense pressure of the predator, us. In addition, these fisheries highlight the fact that many animals are trapped with nets and long lines (dolphins, turtles, birds, etc.). The solutions to these problems are sometimes difficult to apply. These large organisms are usually essential for the health status of the ecosystem and the maintenance of the biodiversity, but we are impacting them in such a way that they have become irrelevant from an ecosystem functioning point of view. The so-called by-catch of smaller organisms is another huge problem. Discards (sometimes more than 50% of fisheries) profoundly harm and transform the ecosystem, and are difficult to sell in the fishing market. Solutions have been sought for decades and this collateral damage has been denounced, but there is still a long way to go. There is also a long way to go to eliminate the high percentage (calculated in more than a quarter of the fish landings of the entire planet) of those known as illegal, unreported and unregulated fisheries. This type of mismanagement of the sea is at the heart of the active policies of many countries, but without transparency and transnational actions, it will it will be difficult to reach a good agreement to suppress or minimize them. In fisheries models, apart from direct impacts, the effects of climate change have long been implemented. As already explained in the previous chapter, rising temperatures and the effects of acidification are transforming the landscape of primary and secondary productivity. The most obvious of these changes is the fact that there will be less fishing, and therefore less production. The effect of lower productivity is already felt in several long-lasting time series, where fishing is being affected by the decrease in phytoplankton. But, in addition, there are less obvious effects. One is the substitution of species, because some are more vulnerable than others to the increase in temperature, so that in the same taxonomic and functional group those who are best adapted to the new conditions win. Another is the expansion of invasive species that directly affect the food chain, and that may feel more comfortable with the new “rules” of fisheries impact and climate change. Some animals are already undergoing these changes, such as cetaceans dying of starvation in certain areas where the synergistic effects of fishing and climate change are felt. The co-governance of fisheries, in which scientists, politicians and society work together, is essential to move forward. They are not hollow words; they are real needs in a world of an excessively accelerated change.
It is difficult to make a synthesis of the new trends in the so-called Blue Growth. This chapter opens a small window with some examples that can serve to understand a little bit the trends of some (not all) sectors that are in full expansion all over the world simultaneously, with their pros and cons. There is a need to change the rules of the game, the paradigms to which we have so far been working with. It is not a simple exercise. It needs a lot of will and a deep understanding of what are the limits and dangers of the old model in which we still live immersed. Many examples show that the actual model runs too fast and has a direct impact on natural resources and ecosystem functioning. In this framework, aquaculture is coming under specific scrutiny. We have gone from an almost negligible aquaculture figure in the ‘70s in terms of fisheries production, to almost half of the biomass extracted from the sea and continental waters from this “farming” activity. This is a considerable achievement, but it has its consequences. The impact of monocultures (salmon, shrimp, etc.) has been, in many places, equal to or worse than overfishing. Eutrophication, salinization, introduction of drugs to contain diseases, the use of wild fish to feed mariculture species or the systematic hunting of potential predators (eagles, seals, etc.) are only some of the problems associated with aquaculture nowadays. The impact on wild ecosystems such as mangroves or fjords is very relevant, and has been highlighted as one of the most important problems to be solved in coastal waters. A new vision is that of the Integrated Multitrophic Aquaculture. This is a method that is gaining strength and that may be the change we need, especially if we move from species of high energy and carbon investment (carnivores) to those species that require less energetic effort (such as bivalves, macroalgae, holothurians, etc.). To do this, one of the first things to do is a good forecast of the impact of climate change, selecting the most suitable organisms (and areas) according to the changing environmental conditions. The regional possibilities (i.e., those areas that may be suitable for a mariculture expansion) and the carrying capacity of the surrounding ecosystems according to different areas must also be taken into account if we want a significant paradigm change. Also, the inclusion of stakeholders and clear co-governance roles of these kind of infrastructures has to be understood as a tool to a successful management of the products that will be available for the local people. The Blue Growth related to the mariculture is not the only open front for the future. The use of microalgae is another type of approach to a future in which low-energy cost organisms are gradually taking center stage. The possibilities have a wide spectrum, and now these microorganisms are beginning to be applied industrially in nutraceuticals, biofuels or for the generation of interesting molecules for biomedical applications. The solutions are there, and changing the priorities and the way we apply the different discoveries to be in line with SDG14 in this Blue Growth strategy is a challenge. In fact, it is not all positive prospects in Blue Growth. There are cases in which excessive acceleration of production and inadequate management of “new generation” resources can cause stress on systems, especially in places with fragile ecosystem balances. In addition, considering the production of alternative energies such as offshore wind, or the new planning of maritime traffic, we have to deeply change our way to proceed. The Blue Growth roadmap must change the paradigm if we really want to consider it sustainable. New solutions and new perspectives in a changing world that require spatial planning and a very different model of resource management than the one we are now applying are urgently needed, considering new models of production, economy and social interaction.
The acceleration of the processes of biodiversity loss and complexity has gone too far, putting ourselves as a species in a crossroads. We now understand that it is not enough to conserve, we need to regenerate. That regeneration goes through two different paradigm changes. The first takes into account upscaling plans. That concept is based on the fact that restoration to regenerate ecosystems is on the verge, but there is a lack of a good plan to create large-scale animal and plant forest restoration programs in different areas of the oceans. The second paradigm is the participation of people, but not only as volunteers; the restoration plans need them as customers. The first paradigm is closely linked to the second. There has to be a business model that allows, in part, to pay for conservation and restoration, which, in turn, will allow for regeneration. However, we are not talking about a privatization process, as has sometimes been attempted. It is not about allowing access only to those who can afford it. Is about making people of different economic statuses and possibilities a part of the process of restoring, and giving them a real return in terms of awareness, education and enthusiasm related to the enhancement and recovery of biodiversity and complexity. People are willing to pay to maintain that complexity, that beauty, that diversity of animals and plants. Tourism can, therefore, make a difference in new conservation plans. It is not enough to expand marine protected areas, we must provide financial mechanisms so that the surveillance and infrastructure of the area we want to regenerate can be maintained. At the same time that this area is preserved, it can be replanted. Methods to quantify biodiversity, calculate the metabolism of the system and recover degraded areas with underwater gardening exist. It is demonstrated, for example, in the advances made in transplant methods for phanerogams, the environmental DNA to calculate the biodiversity of the area, and the calculations on the state of health of a coral reef. However, technology and great advances are not enough. We need to implement an inclusive policy in which local people, especially indigenous people, help in both conservation and restoration processes. They are the first that want (and need) to maintain or recover the lost habitats, but in many cases the policy makers and some stakeholders do not consider them in the equation. We must create those conditions of synergy in which the academic world, the political world and society itself (local and foreign) come together to solve the problems related to the loss of ecosystem services in the oceans.
Microplastic pollution is a major global environmental threat that has attracted increasing interest from the scientific community over the past decade. The semi-closed and highly urbanized Mediterranean Sea has been investigated since 2012, in several specific studies that have identified it as a target hotspot for microplastic contamination. The marine coastal zone of the Salento peninsula (Apulia, Italy) has peculiar geographical and hydrodynamic features, although there are few published data detailing the level of microplastics present in this area. The present manuscript contains both data on the concentration of microplastics in surface waters and the level of microplastics ingested by selected marine organisms in the Salento coastal zone. Microplastics floating on the water surface were monitored during Autumn 2020 and Spring 2021 using neuston Manta net at three different distances from the coasts (Lizzano, Gallipoli and Otranto). The level of microplastic ingestion was monitored in fish species (Sardina pilchardus, Boops boops, Mullus barbatus) and in mussels (Mytilus galloprovincialis). Episodic peaks of microplastic concentrations were found on the sea surface during transects performed in the 3 nautic miles from the seashore. High values of ingested microplastics were found in S. pilchardus. and B. boops (5.4 and 4.6 items/individual respectively). A higher concentration of microplastics was detected in the Adriatic Sea than in the Ionian Sea by comparing the gastrointestinal tract of S. pilchardus and B. boops, in the monitored areas. These results are correlated with the concentration of floating microplastics, although this last result is not validated by statistical analysis. These results support the effectiveness of S. pilchardus and B. boops used as targets in monitoring activity for these pollutants. Results show a worrying increase in the concentration of microplastics on the sea surface and in the gastrointestinal tract of the target species compared to data reported in the literature.
Full-text available
Recent studies have demonstrated the negative impacts of microplastics on wildlife. Therefore, the presence of microplastics in marine species for human consumption and the high intake of seafood (fish and shellfish) in some countries cause concern about the potential effects of microplastics on human health. In this brief review, the evidence of seafood contamination by microplastics is reviewed, and the potential consequences of the presence of microplastics in the marine environment for human food security, food safety and health are discussed. Furthermore, challenges and gaps in knowledge are identified. The knowledge on the adverse effects on human health due to the consumption of marine organisms containing microplastics is very limited, difficult to assess and still controversial. Thus, assessment of the risk posed to humans is challenging. Research is urgently needed, especially regarding the potential exposure and associated health risk to micro- and nano-sized plastics.
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Microplastics are a ubiquitous pollutant in our seas today and are known to have detrimental effects on a variety of organisms. Over the past decade numerous studies have documented microplastic ingestion by marine species with more recent investigations focussing on the secondary impacts of microplastic ingestion on ecosystem processes. However, few studies so far have examined microplastic ingestion by mesopelagic fish which are one of the most abundant pelagic groups in our oceans and through their vertical migrations are known to contribute significantly to the rapid transport of carbon and nutrients to the deep sea. Therefore, any ingestion of microplastics by mesopelagic fish may adversely affect this cycling and may aid in transport of microplastics from surface waters to the deep-sea benthos. In this study microplastics were extracted from mesopelagic fish under forensic conditions and analysed for polymer type utilising micro-Fourier Transform Infrared Spectroscopy (micro-FTIR) analysis. Fish specimens were collected from depth (300–600 m) in a warm-core eddy located in the Northwest Atlantic, 1,200 km due west of Newfoundland during April and May 2015. In total, 233 fish gut contents from seven different species of mesopelagic fish were examined. An alkaline dissolution of organic materials from extracted stomach contents was performed and the solution filtered over a 0.7 μm borosilicate filter. Filters were examined for microplastics and a subsample originating from 35 fish was further analysed for polymer type through micro-FTIR analysis. Seventy-three percent of all fish contained plastics in their gut contents with Gonostoma denudatum having the highest ingestion rate (100%) followed by Serrivomer beanii (93%) and Lampanyctus macdonaldi (75%). Overall, we found a much higher occurrence of microplastic fragments, mainly polyethylene fibres, in the gut contents of mesopelagic fish than previously reported. Stomach fullness, species and the depth at which fish were caught at, were found to have no effect on the amount of microplastics found in the gut contents. However, these plastics were similar to those sampled from the surface water. Additionally, using forensic techniques we were able to highlight that fibres are a real concern rather than an artefact of airborne contamination.
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Microplastic pollution is increasingly becoming a great environmental concern worldwide. Microplastics have been found in many marine organisms as a result of increasing plastic pollution within marine environments. However, the relationship between micoplastics in organisms and their living environment is still relatively poorly understood. In the present study, we investigated microplastic pollution in the water and the mussels (Mytilus edulis, Perna viridis) at 25 sites along the coastal waters of China. We also, for the first time, conducted an exposure experiment in parallel on the same site using M. edulis in the laboratory. A strong positive linear relationship was found between microplastic levels in the water and in the mussels. Fibers were the dominant microplastics. The sizes of microplastics in the mussels were smaller than those in the water. During exposure experiments, the abundance of microbeads was significantly higher than that of fibers, even though the nominal abundance of fibers was eight times that of microbeads. In general, our results supported positive and quantitative correlations of microplastics in mussels and in their surrounding waters and that mussels were more likely to ingest smaller microplastics. Laboratory exposure experiment is a good way to understand the relative impacts of microplastics ingested by marine organisms. However, significant differences in the results between exposure experiments and field investigations indicated that further efforts are needed to simulate the diverse environmentally relevant properties of microplastics.
Technical Report
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Plastic production has increased exponentially since the early 1950s and reached 322 million tonnes in 2015, this figure does not include synthetic fibres which accounted for an additional 61 million tonnes in 2015. It is expected that production of plastics will continue to increase in the foreseeable future and production levels are likely to double by 2025. Inadequate management of plastic waste has led to increased contamination of freshwater, estuarine and marine environments. It has been estimated that in 2010 between 4.8 million to 12.7 million tonnes of plastic waste entered the oceans. Abandoned, lost or otherwise discarded fishing gears (ALDFG) are considered the main source of plastic waste by the fisheries and aquaculture sectors, but their relative contribution is not well known at regional and global levels. Microplastics are usually defined as plastic items which measure less than 5 mm in their longest dimension, this definition includes also nanoplastics which are particles less than 100 nanometres (nm) in their longest dimension. Plastic items may be manufactured within this size range (primary micro- and nanoplastics) or result from the degradation and fragmentation of larger plastic items (secondary micro- and nanoplastics). Microplastics may enter aquatic environments through different pathways and they have been reported in all environmental matrices (beaches, sediments, surface waters and water column). Ingestion of microplastics by aquatic organisms, including species of commercial importance for fisheries and aquaculture, has been documented in laboratory and field studies. In certain field studies it has been possible to source ingested microplastics to fisheries and aquaculture activities. Microplastics contain a mixture of chemicals added during manufacture, the so-called additives, and efficiently sorb (adsorb or absorb) persistent, bioaccumulative and toxic contaminants (PBTs) from the environment. The ingestion of microplastics by aquatic organisms and the accumulation of PBTs have been central to the perceived hazard and risk of microplastics in the marine environment. Adverse effects of microplastics ingestion have only been observed in aquatic organisms under laboratory conditions, usually at very high exposure concentrations that exceed present environmental concentrations by several orders of magnitude. In wild aquatic organisms microplastics have only been observed within the gastrointestinal tract, usually in small numbers, and at present there is no evidence that microplastics ingestion has negative effects on populations of wild and farmed aquatic organisms. In humans the risk of microplastic ingestion is reduced by the removal of the gastrointestinal tract in most species of seafood consumed. However, most species of bivalves and several species of small fish are consumed whole, which may lead to microplastic exposure. A worst case estimate of exposure to microplastics after consumption of a portion of mussels (225 g) would lead to ingestion of 7 micrograms (µg) of plastic, which would have a negligible effect (less than 0.1 percent of total dietary intake) on chemical exposure to certain PBTs and plastic additives.
This study estimates for the very first time plastic litter levels in sea cucumbers (Echinodermata, Holothuroidea) sampled in situ and their intakes from sediments in three different rocky bottom habitats (slides, cliff, banks) settled in Salina Island (Aeolian Archipelago). Macroplastic were never recorded while meso- and microplastics were identified in all sediment (81–438 items/kg d.w.) and animal samples (1.8–22 items/ind.). Plastic intakes by sea cucumbers resulted frequently associated to the size range included within 100–2000 μm. Over than 70% of ingested plastic litter is represented by the size fraction >500 μm. Sediment/animals ratios % are included 2.7 ± 2.0% in studied habitats with a selective intake of fragments occurring in slides. Furthermore, results support the occurrence of selective ingestion of plastic litter by holothurians in natural environments underlining the role of these species in microplastic transfer from abiotic towards biotic compartments of the marine trophic web.
To evaluate rate of migration from plastic debris, desorption of model hydrophobic organic chemicals (HOCs) from polyethylene (PE)/polypropylene (PP) films to water was measured using PE/PP films homogeneously loaded with the HOCs. The HOCs fractions remaining in the PE/PP films were compared with those predicted using a model characterized by the mass transfer Biot number. The experimental data agreed with the model simulation, indicating that HOCs desorption from plastic particles can generally be described by the model. For hexachlorocyclohexanes with lower plastic-water partition coefficients, desorption was dominated by diffusion in the plastic film, whereas desorption of chlorinated benzenes with higher partition coefficients was determined by diffusion in the aqueous boundary layer. Evaluation of the fraction of HOCs remaining in plastic films with respect to film thickness and desorption time showed that the partition coefficient between plastic and water is the most important parameter influencing the desorption half-life.
Microplastic research in recent years has shown that small plastic particles are found almost everywhere we look. Besides aquatic and terrestrial environments, this also includes aquatic species intended for human consumption and several studies have reported their prevalence in other food products and beverages. The scientific as well as public debate has therefore increasingly focused on human health implications of microplastic exposure. However, there is a big discrepancy between the magnitude of this debate and actual scientific findings, which have merely shown the presence of microplastics in certain products. While plastics can undoubtedly be hazardous to human health due to toxicity of associated chemicals or as a consequence of particle toxicity, the extent to which microplastics in individual food products and beverages contribute to this is debatable. Considering the enormous use of plastic materials in our everyday lives, microplastics from food products and beverages likely only constitute a minor exposure pathway for plastic particles and associated chemicals to humans. But as this is rarely put into perspective, the recent debate has created a skewed picture of human plastic exposure. We risk pulling the focus away from the root of the problem: the way in which we consume, use and dispose of plastics leading to their widespread presence in our everyday life and in the environment. Therefore we urge for a more careful and balanced discussion which includes these aspects.
Micro-plastic particles in the world's oceans represent a serious threat to both human health and marine ecosystems. Once released into the aquatic environment plastic litter is broken down to smaller pieces through photo-degradation and the physical actions of waves, wind, etc. The resulting particles may become so small that they are readily taken up by fish, crustaceans and mollusks. There is mounting evidence for the uptake of plastic particles by marine organisms that form part of the human food chain and this is driving urgent calls for further and deeper investigations into this pollution issue. The present study aimed at investigating for the first time the occurrence, amount, typology of microplastic litter in the gastrointestinal tract of Solea solea and its spatial distribution in the northern and central Adriatic Sea. This benthic flatfish was selected as it is a species of high commercial interest within the FAO GFCM (General Fisheries Commission for the Mediterranean) area 37 (Mediterranean and Black Sea) where around 15% of the overall global Solea solea production originates. The digestive tract contents of 533 individuals collected in fall during 2014 and 2015 from 60 sampling sites were examined for microplastics. These were recorded in 95% of sampled fish, with more than one microplastic item found in around 80% of the examined specimens. The most commonly found polymers were polyvinyl chloride, polypropylene, polyethylene, polyester, and polyamide, 72% as fragments and 28% as fibers. The mean number of ingested microplastics was 1.73 ± 0.05 items per fish in 2014 and 1.64 ± 0.1 in 2015. PVC and PA showed the highest densities in the northern Adriatic Sea, both inshore and off-shore while PE, PP and PET were more concentrated in coastal areas with the highest values offshore from the port of Rimini.
The Mediterranean Sea has been described as one of the most affected areas by marine litter in the world. Although effects on organisms from marine plastic litter ingestion have been investigated in several oceanic areas, there is still a lack of information from the Mediterranean Sea. The main objectives of this paper are to review current knowledge on the impact of marine litter on Mediterranean biodiversity, to define selection criteria for choosing marine organisms suitable for use as bioindicator species, and to propose a methodological approach to assessing the harm related to marine litter ingestion in several Mediterranean habitats and sub-regions. A new integrated monitoring tool that would provide the information necessary to design and implement future mitigation actions in the Mediterranean basin is proposed. According to bibliographic research and statistical analysis on current knowledge of marine litter ingestion, the area of the Mediterranean most studied, in terms of number of species and papers in the Mediterranean Sea is the western sub-area as well as demersal (32.9%) and pelagic (27.7%) amongst habitats. Applying ecological and biological criteria to the most threatened species obtained by statistical analysis, bioindicator species for different habitats and monitoring scale were selected. A threefold approach, simultaneously measuring the presence and effects of plastic, can provide the actual harm and sub-lethal effects to organisms caused by marine litter ingestion. The research revealed gaps in knowledge, and this paper suggests measures to close the gap. This and the selection of appropriate bioindicator species would represent a step forward for marine litter risk assessment, and the implementation of future actions and mitigation measures for specific Mediterranean areas, habitats and species affected by marine litter ingestion.
Microplastics (MPs) are thought to be ingested by a wide range of marine organisms before being excreted. However, several studies in marine organisms from different taxa have shown that MPs and nanoplastics could be translocated in other organs. In this study, we investigated the presence of MPs in the livers of commercial zooplanktivorous fishes collected in the field. The study focuses mainly on the European anchovy Engraulis encrasicolus but concerns also the European pilchard Sardina pilchardus and the Atlantic herring Clupea harengus. Two complementary methodologies were used to attest the occurrence of MPs in the hepatic tissue and to exclude contamination. 1) MPs were isolated by degradation of the hepatic tissue. 2) Cryosections were made on the livers and observed in polarized light microscopy. Both methods separately revealed that MPs, mainly polyethylene (PE), were translocated into the livers of the three clupeid species. In anchovy, 80 per cent of livers contained relatively large MPs that ranged from 124 μm to 438 μm, showing a high level of contamination. Two translocation pathways are hypothesized: (i) large particles found in the liver resulted from the agglomeration of smaller pieces, and/or (ii) they simply pass through the intestinal barrier. Further studies are however required to understand the exact process.