Adriana Giangrande

Adaptation and acclimatization to ocean acidification in marine ectotherms: an in situ transplant experiment with polychaetes at a shallow CO2 vent system

Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organisms ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO2. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2 vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO2. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO2, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO2 environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification.

Pre- and post-settlement events in benthic community dynamics

Abstract In all marine benthic environments, organism replacement depends on recruitment limitation, i.e. the impact of both pre- and post-settlement events on the success of recruitment. The relative contribution of pre- versus post-settlement processes in shaping adult populations has been extensively studied. Most analyses concluded that recruitment limitation is a strong determinant of adults’ density. The magnitude of its limitation depends on context, varies with species, and can be strongly modified by all the events preceding and following recruitment itself. A comparison of the outcome of recruitment limitation on hard- and soft-bottom communities has often been neglected. The rules governing these two environments, in both the inter- and the subtidal, might be inferred only by comparing and possibly integrating soft- and hard-bottom ecologies. The highly variable situation that larvae face in the water column is followed by the variability linked to local features, influencing, in its turn, larval settlement and juvenile survival (post-settlement period). A better knowledge of these processes will be possible only by focusing on their relative importance in the two environments and with research on the brief but significant time of larval settlement.

Distribution of Soft-bottom Polychaetes in Two Coastal Areas of the Tyrrhenian Sea (Italy): Structural Analysis

Abstract Multidimensional statistical analysis was used to study the polychaete distribution in soft-bottoms of two coastal areas of the Tyrrhenian Sea (Italy), which are influenced by the discharges of the rivers Tiber and Ombrone. In both areas the distributional patterns of these organisms are determined mainly by sediment types and related factors such as hydrodynamics, river input, and sedimentation. The grain-size gradient from the coast to the open sea affects not only species composition, but also species richness, diversity and abundance. In both areas three main communities have been identified: a sandy biocoenosis, a mixed-sediment biocoenosis and a muddy biocoenosis. The sandy coastal community is characterized by only a few species, while the intermediate zone of sandy-mud sediments presents the highest species richness and diversity. At the mouth of the River Tiber the influence of the river is more evident than at the mouth of the River Ombrone. This is due to the Tibers greater river flow, which determines an environmental uniformity and a ‘cenotic continuum’ from sandy to muddy communities. This does not occur at the mouth of the Ombrone, where the river flow is less important and the polychaete communities are better defined.

Polychaete zonation and its relation to algal distribution down a vertical cliff in the western Mediterranean (Italy): a structural analysis

Abstract The zonation of polychaetes down a vertical cliff (0–5 m in depth) at Cape Romito, Leghorn, Italy, was investigated. The structural organization of the community changed with depth. A community typical of photophilic environments was found in the superficial zone (0–2 m), while in the deeper zone (3–5 m), a more diversified community characterized by species typical of sciaphilic environments was present. At the surface (0 m) the community was very poor in species and individuals and thus probably corresponds to the midlittoral fringe. In fact, some species typical of the midlittoral zone were found. This distribution pattern was constant for samples taken in February and August 1985. The distribution of polychaetes was closely related to that found for macroalgae. It is hypothesized that algae condition the substratum and that this is the main factor responsible for the zonation of polychaetes.

Effects of offshore platforms on soft-bottom macro-benthic assemblages: A case study in a Mediterranean gas field

The exploitation of fossil fuels in the Mediterranean Sea will likely lead to an increase in the number of offshore platforms, a recognized threat for marine biodiversity. To date, in this basin, few attempts have been made to assess the impact of offshore gas and oil platforms on the biodiversity of benthic assemblages. Here, we adopted a structured experimental design coupled with high taxonomic resolution to outline putative effects of gas platforms on soft-bottom macrofauna assemblages in the North Ionian Sea. The analysis was based on a total of 20,295 specimens of 405 taxa, almost entirely identified at species level. Multivariate and univariate analyses showed idiosyncratic patterns of assemblage change with increasing distance from the platforms. Potential reasons underlying such inconsistency are analyzed and the view that structured experimental monitoring is a crucial tool to quantify the extent and magnitude of potential threats and to provide sound baseline information on biodiversity patterns is supported.

Managing the marine aquarium trade: revealing the data gaps using ornamental polychaetes

The marine aquarium industry has great potential to generate jobs in low-income coastal communities creating incentives for the maintenance of a healthy coral reef, if effectively managed. In the absence of current monitoring or legislation to govern the trade, baseline information regarding the species, number and source location of animals traded is missing despite being critical for its successful management and sustainability. An industry assessment to establish the number and provenance of species of ornamental polychaetes (sabellids and serpulids) traded was undertaken across UK wholesalers and retailers. Six geographical regions exporting fan worms were identified. Singapore contributed the highest percentage of imports, but of only one worm “type” whereas Bali, the second largest source, supplied five different worm “types”. Over 50% of UK retailers were supplied by one wholesaler while the remainder were stocked by a mixture of one other wholesaler and/or direct imports from the source country. We estimate that up to 18,500 ornamental polychaetes (16,980 sabellids and 1,018 serpulids) are sold annually in the UK revealing a drastic underestimation of currently accepted trade figures. Incorrect identification (based on exporting region or visual characteristics) of traded animals exacerbates the inaccuracy in market quantification, although identification of preserved sabellids using published keys proved just as inconclusive with high within-species variability and the potential for new or cryptic species. A re-description of the polychaete groups traded using a combination of molecular and morphological techniques is necessary for effective identification and market quantification. This study provides the first assessment of ornamental polychaetes but more importantly highlights the issues surrounding the collection of baseline information necessary to manage the aquarium trade. We recommend that future management should be community based and site-specific with financial and educational support from NGOs, local governments and industry members.

Nonindigenous species along the Apulian coast, Italy

Thirty-eight nonindigenous marine species (NIS) (macroalgae, sponges, hydrozoans, molluscs, polychaetes, crustaceans, ascidiaceans and fish), are reported from the Apulian coast of Italy. Shipping, aquaculture and migration through the Suez Canal are the main pathways of introduction of the NIS. In Apulian waters, 21% of NIS are occasional, 18% are invasive and 61% are well-established. It is highly probable that more NIS will arrive from warm-water regions, because Mediterranean waters are warming. Furthermore, some of the successful NIS must have the ability to become dormant in order to survive adverse conditions, either seasonal or during long journeys in ballast waters. The identification of NIS depends greatly on the available taxonomic expertise; hence the paucity of taxonomists hinders our knowledge of NIS in our seas. We propose the creation and maintenance of a network of observatories across the Mediterranean to monitor the changes that take place along its coasts.

Factors influencing latitudinal pattern of biodiversity: An example using Sabellidae (Annelida, Polychaeta)

The ‘latitudinal gradient of biodiversity’ hypothesis was tested utilising the geographical distribution of species taxa belonging to the family Sabellidae (Annelida: Polychaeta), one of the polychaete families studied by only a few specialists around the world. An increase in species richness towards the Tropical region was revealed, with an asymmetric distribution between the two hemispheres. Data show that most of the species were found in Northern latitudes, producing a Northern area much richer than the Southern one. The Atlantic-Mediterranean Region was particularly rich, with the number of species close to those from the Indo-Pacific Region. Mediterranean species richness is discussed in the light of the particular history of the basin, also emphasising the importance of naturalistic studies that have made the Mediterranean marine flora and fauna one of the best known in the world. The existence of ‘extrinsic factors’ that obscure the real pattern of distributions is hypothesised. Differences found between the two hemispheres could be attributed primarily to the higher number of specialists working in the Boreal Domains, including the Mediterranean area. Global trends produced by some representative genera are also discussed with respect to the distribution of the taxonomic specialists.

Data integration for European marine biodiversity research: creating a database on benthos and plankton to study large-scale patterns and long-term changes.

The general aim of setting up a central database on benthos and plankton was to integrate long-, medium- and short-term datasets on marine biodiversity. Such a database makes it possible to analyse species assemblages and their changes on spatial and temporal scales across Europe. Data collation lasted from early 2007 until August 2008, during which 67 datasets were collected covering three divergent habitats (rocky shores, soft bottoms and the pelagic environment). The database contains a total of 4,525 distinct taxa, 17,117 unique sampling locations and over 45,500 collected samples, representing almost 542,000 distribution records. The database geographically covers the North Sea (221,452 distribution records), the North-East Atlantic (98,796 distribution records) and furthermore the Baltic Sea, the Arctic and the Mediterranean. Data from 1858 to 2008 are presented in the database, with the longest time-series from the Baltic Sea soft bottom benthos. Each delivered dataset was subjected to certain quality control procedures, especially on the level of taxonomy. The standardisation procedure enables pan-European analyses without the hazard of taxonomic artefacts resulting from different determination skills. A case study on rocky shore and pelagic data in different geographical regions shows a general overestimation of biodiversity when making use of data before quality control compared to the same estimations after quality control. These results prove that the contribution of a misspelled name or the use of an obsolete synonym is comparable to the introduction of a rare species, having adverse effects on further diversity calculations. The quality checked data source is now ready to test geographical and temporal hypotheses on a large scale.

Utilization of the filter feeder polychaete Sabella

The filter feeder sabellid Sabella spallanzanii Gmelin (Polychaeta, Sabellidae) was proposed as biofilter in the treatment of wastes from intensive aquaculture. The species was previously studied concerning reproductive traits and ecological requirements; moreover, previous laboratory experiments indicated a positive action of its feeding activity on solid removal from water column coupled with an interesting microbiological activity. In the present paper data on settlement and growth rate from a natural population, together with data on the bioremediation activity of an adult population, relative to an experiment conducted in a small fish farm are reported. Results seem to encourage further studies on S. spallanzanii for a future utilization in bioremediation of fish farms with recycled water. Data from natural annual settlement indicated, however, the unreliability in obtaining settlers from natural populations, so that the artificial reproduction of the target species will be one of the main points of further investigations.