Marco Sigovini

Saprobity: a unified view of benthic succession models for coastal lagoons

We briefly review and expand upon classic conceptual models describing the succession of benthic communities along a gradient of organic matter (OM) enrichment developed for freshwater (the Saprobity System), coastal marine (the Pearson–Rosenberg [P–R] model) and lagoon (the Guélorget–Perthuisot [G–P] model) ecosystems. Differences and similarities between various approaches and models are highlighted and the P–R and G–P models are unified under a single conceptual framework of habitat saprobity in coastal lagoons. We refer to saprobity as the state of an aquatic ecosystem resulting from the input and decomposition of OM and the removal of its catabolites. In addition to other factors, such as salinity, saprobity is viewed as a selection factor for species diversity. The higher the saprobity is, the more impaired the system is, with progressively poorer benthic communities characterized by species that are increasingly tolerant of reducing conditions and toxicity. In coastal lagoons, these processes are strongly driven by hydrodynamics, which govern the land–sea gradient. Based on our review and analysis, we find that saprobity can be a useful descriptor of ecosystem state as determined by OM metabolism, suitable for characterizing the natural conditions of coastal lagoons and assessing their quality.

Connectivity in Three European Coastal Lagoons

The temporal variation and the spatial structure of marine populations strongly depend on the early life stages of the individuals and on their interaction with the environment. The physical dispersion of propagules (eggs and larvae) is a fundamental aspect, conditioning the successful recruitment of juveniles in the adult population. Coastal transitional ecosystems such as lagoons plays a role of nursery for species with economic relevance, such as demersal fishes, mollusks and crustaceans. Those environments promote the recruitment of the early stages for several organisms because they act as area of retention for propagules and concentration for resources. We applied in three different European coastal lagoon a lagrangian particle tracking model coupled with a hydrodynamic model, and developed a method to evaluate the connectivity inside a lagoon and between a lagoon and the sea. Each particle represents a generic passive pelagic larva with a duration of one month. The average connectivity has been estimated after two years of simulation under realistic tide and wind forcings. Our results allow to characterize the lagoons behavior considering different spatial scales and to compare the dynamics of different systems. This study is a first step toward a better knowledge of the factors influencing the ecological role of coastal lagoons.

M-AMBI revisited: looking inside a widely-used benthic index

M-AMBI is a multimetric index for assessing the ecological quality status of marine and transitional waters. It is based on benthic macroinvertebrates and integrates AMBI, a biotic index based on species sensitivity/tolerance, with diversity and richness, making it compliant with the European Water Framework Directive. The success of AMBI paved the way for the introduction of M-AMBI, which was subsequently incorporated into the regulations of several European countries. The M-AMBI algorithm integrates the metrics by means of factor analysis (FA). In this paper, we first reproduced the algorithm using the open source R software. This enabled us to point out that FA is not functional to M-AMBI, and its omission does not appreciably change the results. We then enhanced the applicability of the index, making it independent of the number of samples. In this way, M-AMBI is closely approximated by the simple mean of the normalised metrics with no need for multivariate techniques. Finally, we further simplified the approach, presenting a bivariate version that is still highly correlated with M-AMBI, in which the constitutive metrics are reduced to a diversity measure and a species sensitivity index. The properties of this bivariate version include simplicity, transparency, robustness, and openness.

Mercury in the food chain of the Lagoon of Venice, Italy

Sediments and biota samples were collected in a restricted area of the Lagoon of Venice and analysed for total mercury, monomethyl mercury (MMHg), and nitrogen and carbon isotopes. Results were used to examine mercury biomagnification in a complex food chain. Sedimentary organic matter (SOM) proved to be a major source of nutrients and mercury to primary consumers. Contrary to inorganic mercury, MMHg was strongly biomagnified along the food chain, although the lognormal relationship between MMHg and δ(15)N was less constrained than generally reported from lakes or coastal marine ecosystems. The relationship improved when logMMHg concentrations were plotted against trophic positions derived from baseline δ(15)N estimate for primary consumers. From the regression slope a mean MMHg trophic magnification factor of 10 was obtained. Filter-feeding benthic bivalves accumulated more MMHg than other primary consumers and were probably important in MMHg transfer from sediments to higher levels of the food chain.

A new geographical record of Polycera hedgpethi Er. Marcus, 1964 (Nudibranchia: Polyceridae) and evidence of its established presence in the Mediterranean Sea, with a review of its geographical distribution

Abstract This article reports the first record of the Nudibranch Polycera hedgpethi in the Lagoon of Venice (Italy), as well as its established presence in the Mediterranean Sea after its first record in 1986 in lake Fusaro (Naples). In less than 50 years P. hedgpethi has spread throughout the worlds temperate and subtropical waters, preferring protected coastal environments and other semi-enclosed coastal water bodies such as ports, harbours and lagoons. Shipping is the most likely vector. The species distribution shows a temperate–subtropical range, at about 7–45° of latitude both North and South. Polycera hedgpethi was collected during a survey in 2009 and its presence confirmed for the following two years. All individuals collected were found attached to the bryozoan Bugula neritina, to which it is linked trophically, suggesting a determined pattern of distribution. The present finding is the northernmost record for the species.

Open Nomenclature in the biodiversity era

Summary The uncertainty or the provisional status of a taxonomic identification can be expressed by a set of terms and abbreviations known as Open Nomenclature (ON) qualifiers. This approach is widely applied across biological disciplines, and a high amount of biodiversity data left in ON can be found in literature and data bases. However, there is no consensus about ON qualifiers and their meaning. The use of ON qualifiers has been reviewed in order to provide a summary and guide to current practice in zoology. Some recommendation is given to avoid inconsistencies or vagueness. A flow chart is proposed to clarify the sources of uncertainties during identification and to facilitate the application of ON qualifiers. This review provides a guide for taxonomists and ecologists currently involved in biomonitoring and biodiversity programmes, as well as for researchers dealing with biodiversity data infrastructures and tools, offering a starting point for a methodological harmonization.

The non-indigenous Paranthura japonica Richardson, 1909 (Isopoda: Anthuroidea: Paranthuridae) from the Mar Piccolo lagoon, Taranto (Italy, Mediterranean Sea).

Several individuals of Paranthura japonica, a non-indigenous isopod species, recently recorded on Italian coasts, have been collected from the Mar Piccolo basin, Taranto (Italy). This finding extends the distributional range of the species southwards in the Mediterranean, including a semi-enclosed coastal basin, which is considered the second Italian hotspot for the introduction of alien species. The characteristics of the place reinforce the hypothesis that its introduction is linked to shellfish trade and farming. Remarks on the morphology and ecology are included.

High resolution multibeam and hydrodynamic datasets of tidal channels and inlets of the Venice Lagoon

Tidal channels are crucial for the functioning of wetlands, though their morphological properties, which are relevant for seafloor habitats and flow, have been understudied so far. Here, we release a dataset composed of Digital Terrain Models (DTMs) extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder (MBES) data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy. The dataset comprises also the backscatter (BS) data, which reflect the acoustic properties of the seafloor, and the tidal current fields simulated by means of a high-resolution three-dimensional unstructured hydrodynamic model. The DTMs and the current fields help define how morphological and benthic properties of tidal channels are affected by the action of currents. These data are of potential broad interest not only to geomorphologists, oceanographers and ecologists studying the morphology, hydrodynamics, sediment transport and benthic habitats of tidal environments, but also to coastal engineers and stakeholders for cost-effective monitoring and sustainable management of this peculiar shallow coastal system.

Building a Natural and Cultural Heritage Repository for the Storage and Dissemination of Knowledge: The Algarium Veneticum and the Archivio di Studi Adriatici Case Study

ABSTRACT The Archivio di Studi Adriatici (ASA) is a repository of the Institute of Marine Sciences (ISMAR-CNR) of Venice. The ASA repository, completely open source and open access, hosts natural collections, heritage books, documents, and maps of the Institute of Marine Sciences. It was developed following the discovery of a historical algal collection at the Biblioteca Storica di Studi Adriatici of Venice. This collection, after having been catalogued, has been digitized with a digital planetary scanner. Digitized specimens and metadata, compiled using Dublin Core and Simple Darwin Core formats, are hosted on a website, based on Fedora Repository and Islandora framework.