Decomposition rate and invertebrate colonization of seagrass detritus along a hydrodynamic gradient in a Mediterranean coastal basin: The Stagnone di Marsala (Italy) case study

International audience; Seagrass leaf litter decomposition is a key component of marine carbon flow driven by both biotic and abiotic factors, including water movement. In this study, we analyse Posidonia oceanica litter decomposition and invertebrate colonization in three sites with different hydrodynamics in a coastal basin. Litterbags were put on the sea bed along a gradient of distance from the open sea, implying a different level of water exchange. Leaf litter mass loss and carbon and nitrogen concentration were analysed, and density and biomass of benthic invertebrates colonizing litterbags were recorded after 3, 7, 14, 47, 101, 152 and 221 days. Results showed that in the most shelte…

Seagrass detritus as marine macroinvertebrates attractor

Seagrasses colonise coastal areas worldwide. Despite their high primary production, a considerable proportion becomes detritus that can be used as food, physical habitat and occasional or permanent shelter by several benthic macroinvertebrates. In turn, macroinvertebrates can contribute to regulating seagrass decomposition, and represent an important trophic link between primary producers and higher consumers. Nonetheless, several factors could modify colonizer responses to this habitat. In this study, we tested if colonisation of the seagrass detritus of Zostera noltei Hornemann, 1832 was related to substrate availability rather than food and whether the colonising assemblages were similar…

Studio della dinamica di decomposizione del detrito fogliare di Posidonia oceanica lungo un gradiente di confinamento in un’area siciliana a caratteristiche lagunari (Stagnone di Marsala)

Morphological response of the larvae of Arbacia lixula to near-future ocean warming and acidification

The distribution of the sea urchin Arbacia lixula, a warm affinity species, has been expanding in the Mediterranean Sea. To address questions on potential for future success of this species in the region, the thermotolerance of larval development was investigated in context of regional warming. The larvae were reared in present day spawning period (20 °C) and warming conditions (+4 = 24 and +6 = 26 °C). As the calcifying larvae of sea urchins are vulnerable to stunted growth caused by ocean acidification, the impact of lower pH (−0.3 pH units) on larval development was also investigated in combination with warming. Morphological traits of the larvae, post-oral length arms, overall length of…

Small-scale patches of detritus as habitat for invertebrates within a Zostera noltei meadow

Abstract Seagrass detritus can attract numerous invertebrates as it provides food and substrate within the meadow or in adjacent environments. Nonetheless, several factors could modify the invertebrate response to this habitat. In this study, we tested if epifaunal colonisation of Zostera noltei detritus was related to substrate availability rather than food and whether colonising assemblages were similar according to the meadow structural complexity. Litterbags filled with natural or artificial detritus were deployed within an eelgrass meadow in a Mediterranean coastal lagoon (Thau lagoon, France). Colonisation appeared to be driven by the presence of detritus, with similar assemblages in …

Dinamica del detrito fogliare fanerogamico lungo un gradiente di confinamento in un’area costiera a caratteristiche lagunari

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…

Seagrasses as biological barriers against anthropic input in coastal marine ecosystems

Studio della comunità associata allo strato fogliare di Posidonia oceanica in sorgenti sottomarine superficiali di CO2

Seagrass litter decomposition in a semi-enclosed coastal ecosystem: a litterbag experiment

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,…

Trophic structure of vermetid reef community: High trophic diversity at small spatial scales

Stable isotopes were used to investigate contributions of autochthonous (i.e. benthic: epilithon and macroalgae) and allochthonous (i.e. pelagic: phytoplankton) organic matter sources to the diet of suspension-feeders, grazers and predators associated to small reef-pools (cuvettes) created by the reef-building species Dendropoma petraeum in the north-western coast of Sicily (Italy). Contributions of potential food sources were calculated using Bayesian mixing-models and integrated to a multivariate approach to highlight the diversity of C and N pathways within Dendropoma cuvettes. Both pelagic and benthic organic matter sources were exploited by benthic consumers, although clear differences…

Trophic Transfer of Trace Elements in an Isotopically Constructed Food Chain From a Semi-enclosed Marine Coastal Area (Stagnone di Marsala, Sicily, Mediterranean)

Trace element accumulation is particularly important in coastal and transitional environments, which act as contaminant buffers between the continental and marine systems. We compared trace element transfer to the biota in two locations with different open-sea exposures in a semi-enclosed marine coastal area (Stagnone di Marsala, Sicily, Italy) using isotopically reconstructed food chains. Samples of sediment, macroalgae, seagrasses, invertebrates, fish, and bird feathers were sampled in July 2006 and analysed for stable carbon and nitrogen isotopes (δ(13)C, δ(15)N) and trace elements (arsenic [As], cadmium [Cd], total mercury [THg], and lead [Pb]). Trophic magnification factors were calcul…

Valutazione dei livelli di alcuni metalli pesanti in una catena del detrito ricostruita attraverso l’analisi degli isotopi stabili di carbonio ed azoto

The fate of terrestrial and riverine materials in a Mediterranean seagrass bed

Indagine sul contributo delle fonti bentoniche e planctoniche alla rete trofica del reef a vermeti

Trace metal transfer in the food webs of a semi-enclosed coastal ecosystem (Stagnone di Marsala, Sicily, Italy)

Seagrass community metabolism in a Mediterranean volcanic vent

Ichthyofauna Trophic structure from three adjacent Mediterranean lagoons.

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

Holothuria tubulosa Gmelin 1791 (Holothuroidea, Echinodermata) enhances organic matter recycling in Posidonia oceanica meadows

Abstract The role of Holothuria tubulosa in organic matter recycling of Posidonia oceanica detritus was estimated in a laboratory feeding experiment. The individual mean ingestion rate of seagrass detritus by holothurians was evaluated and carbon and nitrogen stable isotopes, carbon and nitrogen content and C:N ratio analyzed in H. tubulosa , P. oceanica detritus and surface sediment. Results showed that H. tubulosa is capable of ingesting from 30% to 100% of the detritus produced by P. oceanica meadows, depending on the holothurian density. Stable isotope analysis provided evidence for the assimilation of seagrass detritus by H. tubulosa as their signatures were compatible with 1 trophic l…

Analisi delle fonti di materia organica utilizzate da Dendropoma petraeum (Mollusca, Vermetidae) (Monterosato, 1884), in relazione a diverse condizioni idrodinamiche

Seagrass response to high CO2 in volcanic vents

Contribution of planktonic and benthic food sources to the diet of the reef-forming vermetid gastropod Dendropoma petraeum in the western Mediterranean

Abstract In the Mediterranean Sea, the vermetid Dendropoma petraeum (Monterosato, 1884) forms highly biodiverse reefs that have received increasing attention in recent years although very little is known about the food habit of this species. The main goal of this study was to describe the trophic role of planktonic and benthic food sources for D. petraeum . Specimens from three morphological zones of the reef (inner edge, cuvette and outer edge) at two sites with different wave exposure along the north-western coast of Sicily (Italy; western Mediterranean) were compared for δ 13 C and δ 15 N. Isotopic determinations were also carried out on potential food sources identified in epilithon, re…

Trace element bias in the use of CO2 vents as analogues for low pH environments: Implications for contamination levels in acidified oceans

Abstract Research into the effects of ocean acidification on marine ecosystems has increasingly focused on natural CO 2 vents, although their intrinsic environmental complexity means observations from these areas may not relate exclusively to pH gradients. In order to assess trace element levels and distribution in the Levante Bay (Vulcano Island, NE Sicily, Italy) and its suitability for studying biological effects of pH decline, Ba, Fe and trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V and Zn) in sediment were analysed from 7 transects. Where present, Cymodocea nodosa leaves and epiphytes were also analysed. At the spatial scale of the bay, trace element concentrations in sedim…

Trophic structure and functioning of vermetid reef community based on carbon and nitrogen stable isotope analysis.

Relazioni trofiche dell’epifauna colonizzatrice del detrito fogliare di Posidonia oceanica

Trophic transfer of trace metals in an isotopically constructed food web from a Mediterranean coastal area

Dataset from: Small-scale patches of detritus as habitat for invertebrates within a Zostera noltei meadow

This dataset is related to "Small-scale patches of detritus as habitat for invertebrates within a Zostera noltei meadow" (Valentina Costa, Renato Chemello, Davide Iaciofano, Sabrina Lo Brutto, Francesca Rossi)