Effetti di input ornitogenici sullo stato trofico di un sistema costiero Mediterraneo (laghetti di Marinello, Sicilia, Italia)

Fish assemblages cope with ocean acidification in a shallow volcanic CO2 vent benefiting from an adjacent recovery area

Shallow CO2 vents are used to test ecological hypotheses about the effects of ocean acidification (OA). Here, we studied fish assemblages associated with Cymodocea nodosa meadows exposed to high pCO2/low pH conditions at a natural CO2 vent in the Mediterranean Sea. Using underwater visual census, we assessed fish community structure and biodiversity in a low pH site (close to the CO2 vent), a close control site and a far control site, hypothesising a decline in biodiversity and a homogenization of fish assemblages under OA conditions. Our findings revealed that fish diversity did not show a unique spatial pattern, or even significant relationships with pH, but correlated with seagrass leaf …

Trophic ecology of the swimming crab Polybius henslowii Leach, 1820 in Galician and Cantabrian Seas: Influences of natural variability and the Prestige oil spill

9 pages, 9 figures, 2 tables.-- Printed version published Nov 15, 2008.

The use of very high resolution images for studying Posidonia oceanica reefs

Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. This species can develop a biogenic structure called matte, a typical terraced formation built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface forming reefs (récif barrière), considered natural monuments. Posidonia oceanica reefs are particularly exposed to the ongoing increase in temperature and in storm frequency and intensity due to climate change, with negative repercussions on their conservation. Much more attention must be paid to the implementation of monitoring tools able to detect ear…

Trace elements and stable isotopes in penguin chicks and eggs: A baseline for monitoring the Ross Sea MPA and trophic transfer studies.

Multi-tissue trace elements (TEs), C, N concentrations and stable isotopes (δ13C, δ15N) of chick carcasses and eggs of Adelie and Emperor penguins were studied to i) provide reference data before the recent institution of the Ross Sea Marine Protected Area (Antarctica), and ii) provide conversion factors that allow estimating C, N, δ13C and δ15N in edible tissues from non-edible ones, thus improving the use of stable isotopes in contamination and trophic transfer studies. Higher concentrations of As, Cd, Cr, Cu, Hg, Mn and Pb were found in chick carcasses than in eggs, suggesting increasing contamination in recent decades and high toxicity risks for penguin consumers. Isotopic conversion fa…

Small-scale variability in geomorphological settings influences mangrove-derived organic matter export in a tropical bay

Abstract. Organic matter (OM) exchanges between adjacent habitats affect the dynamics and functioning of coastal systems, as well as the role of the different primary producers as energy and nutrient sources in food webs. Elemental (C, N, C : N) and isotope (δ13C) signatures and fatty acid (FA) profiles were used to assess the influence of geomorphological setting in two climatic seasons on the export and fate of mangrove OM across a tidally influenced tropical area, Gazi Bay (Kenya). The main results indicate that tidal transport, along with riverine runoff, plays a significant role in the distribution of mangrove organic matter. In particular, a marked spatial variability in the export of…

Contaminazione da metalli in tracce in un sistema costiero Mediterraneo (laghetti di Marinello, Sicilia, Italia) e loro trasferimento lungo la rete trofica.

Spatial variations in habitat use and food habits of juvenile and adult fishes in a mangal ecosystem (Gazi Bay, Kenya)

Diet and habitat use influence Hg and Cd transfer to fish and consequent biomagnification in a highly contaminated area: Augusta Bay (Mediterranean Sea)

Abstract Total mercury (T-Hg) and cadmium (Cd) were measured in twenty species of fish to study their bioaccumulation patterns and trophodynamics in the Augusta Bay food web. Adult and juvenile fish were caught in 2012 in Priolo Bay, south of the Augusta harbour (Central Mediterranean Sea), which is known for the high trace element and polycyclic aromatic hydrocarbon contamination level. T-Hg concentration was found to significantly increase along δ15N and from pelagic to benthic sedentary fish, revealing a marked influence of trophic position and habitat use (sensu Harmelin 1987) on T-Hg accumulation within ichthyofauna. Cd showed the opposite pattern, in line with the higher trace element…

Evidences on alterations in skeleton composition and mineralization in a site-attached fish under naturally acidified conditions in a shallow CO2 vent

Abstract Background Ocean acidification may affect fish mineralized structures (i.e. otoliths and skeleton). Methods Here, we compared the elemental composition of muscle and skeleton and the mineral features of skeleton in the site-attached fish Gobius bucchichi naturally exposed to high pCO2/low pH conditions in a shallow CO2 vent with fish of the same species exposed to normal pH. Results Overall, no skeleton malformations were found in both pH conditions, but among-site differences were found in the elemental composition. Interestingly, higher Ca/P values, inducing a moderate skeleton maturation, were found in fish exposed to acidified conditions than in controls. Conclusion Our finding…

Small scale variability of geomorphological settings influences mangrove-derived organic matter export in a tropical bay

Abstract. Organic matter (OM) exchanges between adjacent habitats affect the dynamics and functioning of coastal systems, as well as the role of the different primary producers as energy and nutrient sources in food webs. Elemental (C, N, C : N) and isotope (δ13C) signatures and fatty acid (FA) profiles were used to assess the influence of geomorphological setting in two climatic seasons on the export and fate of mangrove OM across a tidally influenced tropical area, Gazi Bay (Kenya). The main results indicate that tidal transport, along with riverine runoff, play a significant role in the distribution of mangrove organic matter. In particular, a marked spatial variability in the export of …

Bottom-up control on macrobenthic communities in a guanotrophic coastal system.

Soft bottom macrobenthic assemblage and sediment characteristics were studied from autumn 2008 to summer 2009 in three coastal ponds (Marinello ponds, Sicily, Italy) at increasing distances from a gull (Larus michahellis Naumann, 1840) colony to investigate the effect of seabird-induced eutrophication (i.e. guanotrophication) on macrobenthic communities. We hypothesized that enhanced nutrient concentration and organic load caused by guano input significantly alter the sedimentary condition of ponds, affecting benthic fauna through a bottom-up control. Polychaetes were the dominant taxon in the system, followed by amphipods, gastropods and bivalves. Macrobenthic patterns showed high variabil…

Horizontal and vertical food web structure drives trace element trophic transfer in Terra Nova Bay, Antarctica

Abstract Despite a vast amount of literature has focused on trace element (TE) contamination in Antarctica during the last decades, the assessment of the main pathways driving TE transfer to the biota is still an overlooked issue. This limits the ability to predict how variations in sea-ice dynamics and productivity due to climate change will affect TE allocation in the food web. Here, food web structure of Tethys Bay (Terra Nova Bay, Ross Sea, Antarctica) was first characterised by analysing carbon and nitrogen stable isotopes (δ13C, δ15N) in organic matter sources (sediment and planktonic, benthic and sympagic primary producers) and consumers (zooplankton, benthic invertebrates, fish and …

Seabird influence on ecological processes in coastal marine ecosystems: an overlooked role?

Coastal marine ecosystems and especially transitional environments host a large variety of birds, functioning as nesting sites for resident species and corridors for migratory ones. Seabirds activity may trigger movement of nutrients and organic matter between coastal boundaries, affecting their availability and processing. Consequently seabirds are often labelled as biotic vectors. While attention has been focused on the study of biodiversity level and migratory patterns of avifauna, there is little information on the effects of seabirds on ecological features (i.e. trophic status, biodiversity level, food web patterns, transfer of contaminants) in coastal marine ecosystems. To address the…

Element-specific behaviour and sediment properties modulate transfer and bioaccumulation of trace elements in a highly-contaminated area (Augusta Bay, Central Mediterranean Sea)

Abstract High sediment contamination in the coastal area of Priolo Bay, adjacent to the highly-polluted Augusta Harbour, poses serious risks for the benthic communities inhabiting the area. Nevertheless, the transfer of trace elements and consequent bioaccumulation in the biota is an overlooked issue. This study aimed to assess the transfer and bioaccumulation patterns of As, Cd, Ni and Hg to the dominant macroalgae and benthic invertebrates of Priolo Bay. Results revealed different patterns among trace elements (TEs), not driven by sediment contamination but rather by element-specific behaviour coupled with sediment physicochemical properties. Specifically, As accumulated in macroalgae but…

Effects of a small seagull colony on trophic status and primary production in a Mediterranean coastal system (Marinello ponds, Italy)

Abstract Colonies of seabirds have been shown to influence nutrient cycling and primary production of coastal areas, but knowledge is still limited above all for smaller colonies. This study evaluates the influence of a small resident seagull colony (Larus michahellis Naumann, 1840) on a Mediterranean coastal system (Marinello ponds, Sicily, Italy). The presence of ornithogenic organic matter from seagull guano was first assessed at increasing distances from the colony using δ15N to indicate the effects of guano on the trophic status and primary production. The pond directly affected by guano deposition showed an anomalous water and sediment chemistry, especially regarding physico-chemical …

Limited Stress Response to Transplantation in the Mediterranean Macroalga Ericaria amentacea, a Key Species for Marine Forest Restoration

In the Mediterranean Sea, brown macroalgae represent the dominant species in intertidal and subtidal habitats. Despite conservation efforts, these canopy-forming species showed a dramatic decline, highlighting the urge for active intervention to regenerate self-sustaining populations. For this reason, the restoration of macroalgae forests through transplantation has been recognized as a promising approach. However, the potential stress caused by the handling of thalli has never been assessed. Here, we used a manipulative approach to assess the transplant-induced stress in the Mediterranean Ericaria amentacea, through the analysis of biochemical proxies, i.e., phenolic compounds, lipids, and…

Sediment characteristics and macrofauna distribution along a human-modified inlet in the Gulf of Oristano (Sardinia, Italy)

We studied the spatial variability and within-year temporal changes in hydrological features, grain size composition and chemical characteristics of sediments, as well as macrofaunal assemblages, along a heavily modified inlet in the Gulf of Oristano (western Sardinia, Italy). The inlet connects the Cabras lagoon to the gulf through a series of convoluted creeks and man-made structures, including a dam and fish barriers built in the last three decades. Sediments were muddy and mainly composed of the "non-sortable" fraction (i.e., < 8 mu m particle size) in all four areas investigated: Lagoon, Creeks, Channel and Seaward. Along the inlet, however, the ratio between the < 8 mu mn and the 8-64…

Studio della connettività tra Ecosistemi Adiacenti in Ambiente Mediterraneo e Tropicale

Le aree di transizione siciliane: stato dell’arte e sviluppi futuri

A new sustainable formulated feed based on discards from food industries for rearing the sea urchin Paracentrotus lividus (Lmk)

During a 18‐week experiment in a sea‐based system, Paracentrotus lividus was fed with two formulations of a new sustainable feed whose main ingredients were food farming discards, mostly outermost lettuce leaves, in different percentage. Egg white was added as protein source and binder, and a little amount of commercial fish feed was added as lipid source. At the end of the experiment, a high survival rate (&gt;80%) and an increase in test diameter (22%), total weight (130%), gonad weight (240%) and gonad index expressed as size‐adjusted gonad weight (288%) were recorded. Gonads achieved a good colour and high levels of essential and polyunsaturated fatty acids, hence representing a commerc…

Sicilian transitional waters: Current status and future development

To appraise the current knowledge of Sicilian transitional waters (TWs), a review was undertaken of the information available on these ecosystems. In detail, a synthesis of the current status is reported, highlighting for each area the ecological features and status, historical data, conservation regime, environmental emergencies and anthropic pressures to which they are subject. The Sicilian TWs reviewed include coastal ponds and lakes, mires and areas with active and nonactive saltworks. Almost all of these ecosystems are affected by several protection regimes because of their high naturalistic value, although current knowledge is limited and fragmented. A few areas have received more att…

Contamination by trace metals and their trophic transfer to the biota in a Mediterranean coastal system affected by gull guano

Transitional environments are vulnerable interface systems, ecologically connected with adjacent systems by several biotic or abiotic flows. The coastal system of the Marinello ponds (Tyrrhenian Sea, Italy) is affected by a colony of yellow-legged gulls Larus michahellis (Naumann, 1840), resident on the cliff beside the ponds. To investigate the role of the gull colony as a potential source of allochthonous non-essential trace metals (As, Cd, Pb and total mercury, THg) and the consequent metal trophic transfer to the biota in the ponds, we collected guano, surface sediment and biota from 3 ponds with different levels of avian input. The highest concentrations were observed in guano and surf…

Study of the origin and fate of organic matter in a tropical bay using elemental, isotopic and fatty acid biomarkers.

Organic matter (OM) exchanges between adjacent coastal ecosystems affect the role of the different primary producers as energy and nutrient sources in food webs. Elemental and isotope parameters (C/N ratios, δ13C) and fatty acid (FA) biomarkers were used to assess the origin and distribution of OM in both surface sediment and water along a strongly tidally-influenced tropical area, Gazi Bay (Kenya), in two climatic seasons (dry and rainy). Dominant primary producers (i.e. mangroves, macroalgae and seagrasses) were also characterized through the same combined approach. Export of the mangrove-derived OM, highly depleted, to the adjacent bay was evident from a gradual 13C-enrichment of primary…

Ontogenetic trophic segregation between two threatened smooth-hound sharks in the Central Mediterranean Sea

AbstractElasmobranchs are among the species most threatened by overfishing and a large body of evidence reports their decline around the world. As they are large predators occupying the highest levels of marine food webs, their removal can alter the trophic web dynamic through predatory release effects and trophic cascade. Suitable management of threatened shark species requires a good understanding of their behaviour and feeding ecology. In this study we provide one of the first assessments of the trophic ecology of the “vulnerable” smooth-hounds Mustelus mustelus and M. punctulatus in the Central Mediterranean Sea, based on stomach contents and stable isotope analyses. Ontogenetic diet ch…

Influence of seabird guano on the contamination level of a Sicilian coastal area (Marinello ponds).

Bottom-Up Control of Macrobenthic Communities in a Guanotrophic Coastal System

Soft bottom macrobenthic communities were studied seasonally in three coastal ponds (Marinello ponds, Italy) at increasing distances from a gull (Larus michahellis) colony to in- vestigate the effect of seabird-induced eutrophication (i.e. guanotrophication) on macro- benthic fauna.We hypothesized that enhanced nutrient concentration and organic load caused by guano input significantly alter the trophic and sedimentological condition of ponds, affecting benthic fauna through a bottom-up control. The influence of a set of envi- ronmental features on macrobenthic assemblages was also tested. Overall, the lowest macrobenthic abundances and functional group diversity were found in deeper sites,…

Spatial variability in stable carbon and nitrogen isotope ratios in a Mediterranean coastal lagoon (Mauguio, France).

3D-Reconstruction of a Giant Posidonia oceanica Beach Wrack (Banquette): Sizing Biomass, Carbon and Nutrient Stocks by Combining Field Data With High-Resolution UAV Photogrammetry

Beach wracks are temporary accumulations of vegetal detritus that can be found along coastlines all over the world. Although beach wracks are often perceived as a nuisance for beach users, they play a crucial ecological role in carbon and nutrient connectivity across ecosystem boundaries, especially when they reach a relevant size, as in the case of the wedge-shaped seagrass accumulations called banquette. In this study, three-dimensional mapping of a giant Posidonia oceanica banquette was carried out for the first time using high-resolution UAV photogrammetry combined with field sampling and compositional and chemical analysis. The combined approach allowed a reliable estimation of the amo…

Stable isotope and fatty acid analysis reveal the ability of sea cucumbers to use fish farm waste in integrated multi-trophic aquaculture

Stable isotope ratios, carbon (δ13C) and nitrogen (δ15N), and fatty acids validated the trophic connection between farmed fish in a commercial nearshore fish farm and sea cucumbers in the Mediterranean Sea. This dual tracer approach evaluated organic matter transfer in integrated multi-trophic aquaculture (IMTA) and the ability of sea cucumbers to incorporate fish farm waste (fish faeces and uneaten artificial fish feed) into their tissue. Between October 2018 and September 2019, Holothuria (Roweothuria) poli Delle Chiaje, 1824, co-cultured at IMTA sites directly below one of the commercial fish cage , at 10 m and 25 m from the selected fish cage, and at two reference sites over 800 m from …

Macroalgae transplant to detect the occurrence of anthropogenic nutrients in seawater of highly tourist beaches in Mediterranean islands

In the Mediterranean region, islands are among the most important tourist destinations, being sites of considerable naturalistic, historical and cultural importance. This is highly beneficial for local economies, but may also represent a threat for the environment, especially during the peak season (i.e. summer). Indeed, the sharp demographic increase concentrated in a relatively short period may negatively affect the quality of coastal marine systems and the provision of ecosystem services, producing in turn negative feedbacks on tourism industry. Nevertheless, the assessment of the environmental impact of tourism on coastal seawater has been seldom addressed. Here, we show the results of …

Carbon and nitrogen isotopic values in Lithops aucampiae during leaf development.

Abstract Lithops (Aizoaceae) are succulent plants consisting of a pair of opposite succulent leaves inserted on an extremely short stem. The apical meristem produces a new leaf pair that develops between the older pair, recycling water and metabolites. This peculiar anatomy and growth form make ecophysiological studies quite challenging. Lithops are considered to have CAM metabolism, though experimental evidence is scarce. We followed the changes in carbon and nitrogen isotopic values in mature leaves, young leaves and roots, with the aim of investigating how the use of resources is optimized to achieve survival in extremely arid environments. Two-year-old plants of Lithops aucampiae were g…

Trophic structure of zooplankton / suprabenthos communities from the Galician and Cantabrian Coasts (NW Spain) by stable carbon and nitrogen isotope ratios analysis

Lipid and fatty acid biomarkers as proxies for environmental contamination in caged mussels Mytilus galloprovincialis

Mussels (Mytilus galloprovincialis) were transplanted from a reference site (Syracuse harbour) to an impacted site (Augusta Bay) from January to July 2013 to assess the biochemical response of caged mus- sels to high trace element and polycyclic aromatic hydrocarbon (PAH) contamination, using lipid and fatty acid (FA) biomarkers. Sediment and mussels were analysed to assess contaminant bioavailability in the study sites and bioaccumulation in mussel tissue. Trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, Zn) and PAHs were significantly higher in mussels from Augusta than in those from Syracuse, mirror- ing the different environmental contamination. The biological impact quotient (BIQs…

Turning waste into gold: Sustainable feed made of discards from the food industries promotes gonad development and colouration in the commercial sea urchin Paracentrotus lividus (Lamarck, 1816)

Abstract Development of sustainable aquaculture practices is a suitable solution to reduce the pressure on overexploited stocks of the Mediterranean sea urchin, Paracentrotus lividus, and to respond to the increasing market demand. To move forward the Blue Growth and following the principles of circular economy, a three-month feeding experiment was conducted to test a sustainable feed based on food processing discards on sea urchins. Two feed formulations differing on the proportions of the two main ingredients (endive outermost leaves and European anchovy discards in a ratio of 60:40 and 80:20 respectively) were prepared and tested on P. lividus gonad yield, development and quality. The re…

Formulation of a new sustainable feed from food industry discards for rearing the purple sea urchin Paracentrotus lividus

The lack of suitable feeds for echinoculture has led to use natural resources already widely exploited by human activities. To move towards a higher sustainability of echinoculture, this study proposes a sustainable feed for Paracentrotus lividus. Two experimental formulations were obtained using discarded endive (Cichorium endivia) leaves and anchovy (Engraulis encrasicolus) industry discards in different proportions, and agar as a binder. The evaluation of the feed stability showed that the feed was stable for 72 hr, allowing a suitable feeding for sea urchins. Both formulations showed a proper nutritional value and fatty acid profile, corresponding to the features of the main ingredients…

Influence of seabird guano on the trophic status and contamination levels of a Sicilian transitional area

Environmental effects of tourism and its seasonality on Mediterranean islands: the contribution of the Interreg MED BLUEISLANDS project to build up an approach towards sustainable tourism

AbstractThe Mediterranean basin is amongst the world’s main tourist destination, and its islands are a major attraction, being sites of historical, cultural and naturalistic importance. This is beneficial for the local economies, but it may also represent a great burden on the coastal environment, where other human pressures are concentrated. The awareness of detrimental side effects of tourism together with the importance to take into account social and economic facets has led to the concept of sustainable tourism, which, however, represents a goal far from being attained. A good opportunity to promote sustainable tourism was provided by the Interreg MED BLUEISLANDS project, whose main aim…

Trace element and PAH bioaccumulation in caged mussels (Mytilus galloprovincialis) from an industrial area (Augusta Bay, SE Sicily)

Guano-Derived Nutrient Subsidies Drive Food Web Structure in Coastal Ponds.

A stable isotope study was carried out seasonally in three coastal ponds (Marinello system, Italy) affected by different gull guano input to investigate the effect of nutrient subsidies on food web structure and dynamics. A marked 15N enrichment occurred in the pond receiving the highest guano input, indicating that gull-derived fertilization (guanotrophication) had a strong localised effect and flowed across trophic levels. The main food web response to guanotrophication was an overall erosion of the benthic pathway in favour of the planktonic. Subsidized primary consumers, mostly deposit feeders, switched their diet according to organic matter source availability. Secondary consumers and,…

Inter-habitat connectivity in a tropical ecosystem (Gazi Bay, Kenya) as revealed by ichthyofauna

Il macrozoobenthos: uno dei possibili descrittori di stato ecologico nel monitoraggio delle aree di transizione siciliane.

Macrobenthic communities impoverishment in response to seabird input in a Mediterranean transitional area

Seabird influence on ecological processes in coastal marine ecosystems: An overlooked role? A critical review

Abstract Seabirds are vital, but overlooked, components of coastal marine ecosystems and may connect the marine and terrestrial environment at a global scale, significantly contributing to inter-habitat connectivity and the provision of multiple ecosystem services. Although the ecological and functional role of birds in terrestrial areas, islands in particular, has been deeply studied since the last century, the same does not hold true for coastal marine areas. Given the importance of coastal areas for seabirds worldwide and, at the same time, the high vulnerability of both, looking into the role of seabirds in influencing the ecosystem functioning in coastal areas is needed nowadays. Here,…

Gull-derived trace elements trigger small-scale contamination in a remote Mediterranean nature reserve

The role of a yellow-legged gull (Larus michahellis) small colony in conveying trace elements (As, Cd, Cr, Cu, Ni, Pb, THg, V, Zn) was assessed in a Mediterranean nature reserve (Marinello ponds) at various spatial and temporal scales. Trace element concentrations in guano were high and seasonally variable. In contrast, contamination in the ponds was not influenced by season but showed strong spatial variability among ponds, according to the different guano input. Biogenic enrichment factor B confirmed the role of gulls in the release of trace elements through guano subsidies. In addition, comparing trace element pond concentrations to the US NOAA’s SQGs, As, Cu and Ni showed contamination …

Co-existing with the alien: evidence for environmental control on trophic interactions between a native (Atherina boyeri) and a non-indigenous fish species (Gambusia holbrooki) in a Mediterranean coastal ecosystem

Biological invasions are a widespread problem worldwide, as invasive non-indigenous species (NIS) may affect native populations through direct (e. g., predation) or indirect (e.g., competition) trophic interactions, leading to changes in the food web structure. The trophic relationships of the invasive eastern mosquitofish Gambusia holbrooki and the native big-scale sand smelt Atherina boyeri coexisting in three Mediterranean coastal ponds characterized by different trophic statuses (from oligotrophic to hypereutrophic) were assessed in spring through isotopic niche analysis and Bayesian mixing models. The two fish relied on the distinctive trophic pathways in the different ponds, with the …

Intrinsic bioremediation potential of a chronically polluted marine coastal area.

A microbiological survey of the Priolo Bay (eastern coast of Sicily, Ionian Sea), a chronically polluted marine coastal area, was carried out in order to discern its intrinsic bioremediation potential. Microbiological analysis, 16S rDNA-based DGGE fingerprinting and PLFAs analysis were performed on seawater and sediment samples from six stations on two transects. Higher diversity and variability among stations was detected by DGGE in sediment than in water samples although seawater revealed higher diversity of culturable hydrocarbon-degrading bacteria. The most polluted sediment hosted higher total bacterial diversity and higher abundance and diversity of culturable HC degraders. Alkane- an…

First assessment of total organic carbon/macrofauna relation in Sicilian coastal lagoons

Sediment characteristics (Total organic carbon, C/N ratio, carbonates, grain size) and macrofaunal assemblages were studied in Sum- mer 2005 in 9 coastal lagoons of eastern Sicily (Italy) belonging to 3 study areas (Capo Peloro, Marinello and Vendicari). The diffe- rent ecosystems were selected upon their differences in geographical position, size, depth, water exchange, anthropic impact and expec- ted organic matter loading. The aim of this study was to explore the relationship between the Total organic carbon (TOC) content of se- diment and macrofaunal assemblages characteristics, as indicated by the Study Group on Benthic Indicators of IOC/UNESCO (http: //ioc.unesco.org/benthicindicators…

δ15N in deployed macroalgae as a tool to monitor nutrient input driven by tourism activities in Mediterranean islands

Abstract Mediterranean Sea is among the world's leading tourist destinations; however, the sharp increase in tourists during the high season may affect coastal seawater. The main aim of this study was to evaluate the occurrence and temporal variation of anthropogenic nutrients in coastal seawater in relation to tourist flows in three Mediterranean islands (Cyprus, Sicily and Rhodes), through short-term macroalgae deployments, coupled with δ15N analysis and GIS mapping. In all islands, an overall increase in macroalgae δ15N occurred over the deployment carried out in August in the tourist sites, suggesting the presence of anthropogenic nutrients. Decreasing δ15N values occurred at increasing…