Checklist of free-living nematode species in the transitional environment of Lake Varano (Southern Italy)

Llista patró d’espècies de nematodes de vida lliure a l’ambient de transició del llac Varano (sud d’Itàlia)Aquest estudi documenta per primera vegada la composició taxonòmica de la comunitat de nematodes i el nombre d’espècies de nematodes de vida lliure presents al llac Varano, al sud de la mar Adriàtica (Itàlia). La comunitat de nematodes estava composta principalment per espècies típiques dels sediments fins predominants en ambients de transició (TE). En conjunt, es va registrar un nombre elevat d’espècies de nematodes (56) pertanyents a 36 gèneres de 17 famílies. Aquests valors són comparables en gran mesura amb els registrats en altres TE italians, però inferiors als registrats en altres sistemes d’aigües salabroses europeus, probablement en relació amb el baix nivell de salinitat del llac Varano. Es van identificar quaranta taxons a nivell d’espècie, la qual cosa incrementa el nombre d’espècies conegudes de nematodes marins a les costes italianes de 443 a 463, a la conca de l’Adriàtica de 310 a 313 i al sud de la mar Adriàtica de 37 a 77. Atesa la importància d’aquest fílum per a la valoració de la qualitat ecològica i la gran vulnerabilitat dels ecosistemes de la mar Adriàtica, s’hauria de planificar la intensificació de les accions de mostreig, especialment a la part centre-meridional de la conca. Un pla així proporcionaria nous coneixements de la biogeografia d’un dels components més importants del bentos i podria aportar nova informació sobre els efectes de l’escalfament climàtic a la mar Adriàtica.This study documents for the first time the taxonomic composition of the nematode community and the number of free–living nematode species in Lake Varano, Southern Adriatic Sea, Italy. The nematode community was mainly composed of species typical of fine sediments that usually prevail in transitional environments (TEs). An overall high number of nematode species was recorded (55), belonging to 36 genera in 17 families. These values are highly comparable to those reported for other Italian TEs, but appear lower than those recorded in other European brackish–water systems, probably in relation to the low salinity range of Lake Varano. Forty taxa were identified up to species level, thus increasing the number of the nematode marine species known for the Italian coasts from 443 to 463, for the Adriatic basin from 310 to 313, and for the Southern Adriatic sector from 37 to 77. Considering the importance of this phylum in the assessment of ecological quality and the great vulnerability of the Adriatic Sea ecosystems, an intensification of sampling efforts should be planned, especially in the Central–Southern part of the basin. Such a plan would provide new insights into the biogeography of one of the most important components of the benthic domain and potentially yield new information about the climate warming effects on the Adriatic Sea.Lista patrón de especies de nematodos de vida libre en el ambiente de transición del lago Varano (sur de Italia)Este estudio documenta por primera vez la composición taxonómica de la comunidad de nematodos y el número de especies de nematodos de vida libre presentes en el lago Varano, al sur del mar Adriático (Italia). La comunidad de nematodos estaba compuesta principalmente por especies típicas de los sedimentos finos predominantes en ambientes de transición (TE). En conjunto, se registró un elevado número de especies de nematodos (55) pertenecientes a 36 géneros de 17 familias. Estos valores son comparables en gran medida a los registrados en otros TE italianos, pero inferiores a los registrados en otros sistemas de aguas salobres europeos, probablemente en relación con el bajo nivel de salinidad del lago Varano. Se identificaron cuarenta taxones a nivel de especie, lo que incrementa el número de especies conocidas de nematodos marinos en las costas italianas de 443 a 463, en la cuenca del Adriático de 310 a 313 y en el sur del mar Adriático de 37 a 77. Considerando la importancia de este fílum para la valoración de la calidad ecológica y la gran vulnerabilidad de los ecosistemas del mar Adriático, debería planificarse la intensificación de las acciones de muestreo, especialmente en la parte centro-meridional de la cuenca. Un plan de este tipo proporcionaría nuevos conocimientos de la biogeografía de uno de los componentes más importantes del bentos y podría aportar nueva información acerca de los efectos del calentamiento climático en el mar Adriático

A review of Italian research on free-living marine nematodes and the future perspectives on their use as Ecological Indicators (EcoInds)

The use of free-living marine nematodes as ecological indicators (EcoInds) of human impacts has increased greatly in Italy since 1990. This paper is a summary of the Italian research experience in the study of nematode assemblages of shallow water habitats, and provides a breakdown of the most important insights that have been obtained so far. Although nematodes are among the best candidates for the Ecological Quality (EcoQ) assessment in the benthic domain, many guidelines need to be developed and limits overcome. Italian research has certainly contributed to the achievement of this purpose with highly focused local investigations on the effects of specific stressors (riverine and sewage discharge, aquaculture, trace elements and hydrocarbons), but also to a large extent with wider analyses aimed at finding new and valuable tools for monitoring programs and useful nematode descriptors, in line with the European Directives. Currently, the Italian and foreign experiences in this field draw light to the fact that the best nematode descriptors for the EcoQ assessment are the taxonomic composition and life strategy traits. However, nematode worldwide research is running the risk of being marginalized because of the relatively narrow scope of most contemporary studies. Nematode researchers should work in a nematologist community in order to better promote the use of nematodes such as EcoInds in the era of the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD). In the present paper, possible steps to obtain this goal are brought to the reader's attention and discussed

Assessment of the ecological quality (EcoQ) of the Venice lagoon usingthe structure and biodiversity of the meiofaunal assemblages

partially_open3noTransitional Environments (TEs) have been deeply modified to meet human requirements, and for thisreason are currently ranked among the most endangered aquatic ecosystems. The Adriatic basin hosts alarge number of TEs of which the Lagoon of Venice is the largest one, but information on its meiofauna arevery dated or focused to localized areas. The present study is the first to document the spatial distributionof meiofauna in the whole Venice lagoon. Furthermore, the health status of the TE of Venice has beenassessed by means of several faunal parameters (richness, diversity indices, structure of the entire meio-faunal assemblage and only rare taxa). All the univariate meiofaunal parameters (i.e. richness, diversityindices, Ne:Co ratio) were consistent in highlighting the worst ecological quality of the Porto Margheradistrict. Instead, the structure of the entire meiofaunal assemblage as well as that of rare taxa seemed todetect variations not directly related to pollution and likely due to the different hydrodynamic conditionsof Lido and Malamocco inlets. On the basis of our results, we have also critically discussed the usefulnessof the various faunal parameters in the monitoring assessment of the TEs.openSemprucci, Federica; Balsamo, Maria; Sandulli, RobertoSemprucci, Federica; Balsamo, Maria; Sandulli, Robert

New Data on Reproductive System and Spermatozoa Confirm Macrodasys as a Model in Comparative Reproductive Analysis in Macrodasyida (Gastrotricha)

Gastrotricha Macrodasyida, aquatic worms, are primarily hermaphrodites with internal cross-fertilization and indirect sperm transfer. Insightful information on this matter dates to 1978 and derives from an illuminating work focused on two Macrodasys species. The role as a “model” of this taxon clashes, however, with the relative paucity of data concerning the ultrastructure of the accessory organs involved in the sperm transfer. Therefore, we have undertaken a new study on three additional species of Macrodasys focusing on the frontal and caudal organs and also on the spermatozoa. Our observations confirmed the structural plan of the reproductive system reported for the genus, but found some differences concerning the accessory reproductive organs. Most importantly, we found spermatozoa inside the caudal organ of several single specimens, suggestive of a more plausible hypothesis about sperm transfer modality in Macrodasys. In the spermatozoa, the position of the mitochondrion outside rather than inside the nucleus has been confirmed as a major difference between the spermatozoa of Macrodasys species and those of the other Macrodasyida. We suggest that the peculiar structure of the mature spermatozoon of Macrodasys could derive from an incomplete process of spermatogenesis and hence it would be useful to infer phylogenetic alliances

The nematode assemblage as a tool for the assessment of marine ecological quality status: a case-study in the Central Adriatic Sea

Free-living nematodes are efficiently used as bio-indicators of anthropogenic disturbance in marine ecosystems. Among various criteria, functional traits may represent useful tools for monitoring environmental impact in coastal areas. A study of nematode assemblages was carried out in three locations of the Central Adriatic Sea (Italy), one at the mouth of the Foglia River (Baia Flaminia) and two enclosed in the Monte San Bartolo Natural Park (Monte Brisighella and Fiorenzuola di Focara). Taxonomic composition and the functional traits of the nematode assemblage revealed a possible influence of the organic load of the Foglia River. Biotic data, as well as environmental parameters, suggested a particularly negative impact of the river on the assemblage at Baia Flaminia. Here, the increasing impact of the river led to a rise in the relative abundance of r-strategist genera like Chromadora, Sabatieria and Viscosia. Poor ecological conditions were also present at Brisighella, where the river might exert its influence due to the presence of long shore currents. In contrast, the results revealed that the best ecological quality was at Fiorenzuola di Focara, where the impact of anthropogenic activities was generally irrelevant. This study documents how nematodes can be used as an early warning indicator with which to monitor the health quality of vulnerable littoral areas

Sessile macrobenthos (Ochrophyta) drives seasonal change of meiofaunal community structure on temperate rocky reefs

none7noUnlike the soft bottom meiofauna, meiofauna associated to hard substrata is poorly studied, despite its ecological relevance. Since communities of hard substrata are usually characterized by species with different life cycles and strategies from those of soft bottom assemblages, information on hard substrata meiofauna is still needed. In this study, sessile macrobenthos and the associated meiofaunal assemblages of two sites of Portofino (NW Mediterranean) were investigated in two seasons at three different depths on both sub-vertical and inclined reefs. The study aimed to assess the abundance, diversity and composition of the meiofauna and the factors structuring its assemblages. Moreover, as meiofauna is known to be dependent upon the substrate characteristics, the study investigated whether the meiofaunal patterns could be related to the sessile macrobenthos structure and composition, and to which extent. Macroalgae dominated the sessile macrobenthic assemblages, while Nematoda and Copepoda were the main meiofaunal groups. Meiofaunal higher-taxa richness and diversity resulted very high, due to the large number of different microhabitats offered by macroalgae. Macrobenthic assemblages were dominated by Rodophyta and Ochrophyta in summer, the latter dramatically collapsing in winter. The meiofaunal abundance and composition changed significantly with the season, consistently with the sessile macrobenthic assemblages, and resulted strongly correlated with Ochrophyta. Shaping the meiofaunal assemblages, macroalgae appeared to act as ecosystem engineer for the meiofauna.openLosi, V; Sbrocca, C; Gatti, G; Semprucci, F; Rocchi, M; Bianchi, C N; Balsamo, MLosi, V; Sbrocca, C; Gatti, G; Semprucci, F; Rocchi, M; Bianchi, C N; Balsamo,

Antarctic Special Protected Area 161 as a Reference to Assess the Effects of Anthropogenic and Natural Impacts on Meiobenthic Assemblages

The Antarctic region is usually considered a pristine area. Nevertheless, regional warming effects and increasing human activities, including the presence of several research stations, are inducing considerable environmental changes that may affect the ecosystem’s functions. Therefore, during the XXXIII Antarctic expedition, we carried out an investigation in Terra Nova bay (Ross Sea), close to the Antarctic Specially Protected Area (ASPA) n.161. In particular, we compared the effects of two different types of impacts on the meiobenthic assemblages: anthropogenic impact (AI), associated with the activity of Mario Zucchelli Research Station (MZS), and natural impact (NI) attributable to a large colony of Adélie penguins (Pygoscelis adeliae) in Adelie Cove. For each impacted site, a respective control site and two sampling depths (20 and 50 m) were selected. Several environmental variables (pH, dissolved oxygen, major and minor ions, heavy metals, organic load, and sediment grain size) were measured and analysed, to allow a comprehensive characterization of the sampling areas. According to the criteria defined by Unites States Environmental Protection Agency (US EPA 2009), heavy metal concentrations did not reveal critical conditions. However, both the MZS (AI20) and penguin colony (NI20) sites showed higher heavy metal concentrations, the former due to human activities related to the Italian research station, with the latter caused by the penguins excrements. Meiobenthic richness and abundance values suggested that the worst ecological condition was consistently related to the Adélie penguins colony. Furthermore, the higher contribution of r-strategists corroborates the hypothesis that the chronic impact of the penguin colonies may have stronger effects on the meiobenthos than the human activities at the MZS. Food is not limited in shallow Antarctic bottoms, and microscale differences in primary and secondary production processes can likely explain the greater spatial heterogeneity, highlighted both by the univariate and multivariate attributes of meiobenthic assemblage (i.e., richness, diversity, abundance, whole structure assemblage, and rare taxa) at the deeper stations. As reported in other geographical regions, the assemblage structure of rare meiobenthic taxa is confirmed to be more susceptible to environmental variations, rather than the whole assemblage structure