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

Essential Oils as Nematicides in Plant Protection—A Review.

By 2030, the European Commission intends to halve chemical pesticide use and its consequent risks. Among pesticides, nematicides are chemical agents used to control parasitic roundworms in agriculture. In recent decades, researchers have been looking for more sustainable alternatives with the same effectiveness but a limited impact on the environment and ecosystems. Essential oils (EOs) are similar bioactive compounds and potential substitutes. Different studies on the use of EOs as nematicides are available in the Scopus database in the scientific literature. These works show a wider exploration of EO effects in vitro than in vivo on different nematode populations. Nevertheless, a review of which EOs have been used on different target nematodes, and how, is still not available. The aim of this paper is to explore the extent of EO testing on nematodes and which of them have nematicidal effects (e.g., mortality, effects on motility, inhibition of egg production). Particularly, the review aims to identify which EOs have been used the most, on which nematodes, and which formulations have been applied. This study provides an overview of the available reports and data to date, downloaded from Scopus, through (a) network maps created by VOSviewer software (version 1.6.8, Nees Jan van Eck and Ludo Waltman, Leiden, The Netherlands) and (b) a systematic analysis of all scientific papers. VOSviewer created maps with keywords derived from co-occurrence analysis to understand the main keywords used and the countries and journals which have published most on the topic, while the systematic analysis investigated all the documents downloaded. The main goal is to offer a comprehensive understanding of the potential use of EOs in agriculture as well as which directions future research should move toward

Simple, inexpensive, and rapid approach to detect changes in the structure of soil free-living nematodes.

A general limitation of ecological investigations based on nematodes is related to the diffi cult and time-consuming taxonomic identifi cation of species. Therefore, nematologists are investing many efforts to develop alternative approaches as proxies applicable in biomonitoring assessment. Recently, an alternative method that combines morpho-functional traits was proposed for detecting assemblage changes of marine nematodes. In view of the promising results, it was tested the same approach to document taxonomic structure changes of soil free-living and plant parasitic nematodes. Specifi cally, this attempt was carried out using three data sets that include studies from various European regions and different types of ecosystems: forests, grasslands and maize crops. Multivariate statistical analysis revealed that the simple combination of the four traits (i.e., buccal cavity cuticularization occurrence, amphideal fovea size and shape, morphology of the cuticle and pharynx) in a single code number perfectly mirrors the taxonomic structure trends of the nematode assemblage at genus level. Therefore, we predict that similar results can be also obtained by directly encoding nematode specimens with the selected traits and we point to new important advances if this procedure can be coupled with advanced machine learning

Taxonomic and functional nematode diversity in Maldivian coral degradation zones: patterns across reef typologies and depths

The intensification of dredging and infilling activities in lagoons and on coral reefs are common practices in the Maldivian archipelago, and these activities alter the biodiversity of the bioconstructors and the functioning of the ecosystem. The alteration of environmental factors can also affect inconspicuous fauna, such as free-living nematodes. The implications of a reduction in biodiversity may transcend decreased taxonomic diversity, resulting in changes in functional diversity and redundancy; however, how the environmental conditions and human pressure affects the functionality of nematodes in Maldivian coral degradation zones (CDZs) remain poorly understood. In this paper, we examined changes in the taxonomic and functional diversity and the functional redundancy in nematode communities regarding the geographic location (atolls with various levels of human pressure), the exposure and topography of the reef (lagoon and ocean), the slope of the reef, and the depth. The functional diversity and redundancy were evaluated by considering two main biological traits of nematodes: i) the trophic strategy, and ii) the life strategy. The extremely high number of nematode genera observed in the Maldives is supported by the high complexity of the carbonate sediments. The reef exposure and depth were the most relevant environmental factors that influenced the taxonomic and functional diversity. The functional diversity, according to the trophic strategies, mirrored the taxonomic diversity because the adaptive plasticity of nematode buccal cavity structures is closely associated with the high biodiversity of the phylum. The high abundance of k-strategists in ocean reefs may indicate a higher ecological quality when compared to lagoon reefs; however, the absence of significant differences in life strategy functional diversity and functional redundancy indicates that a recovery process is underway. Analyses of nematode communities should be combined with standard investigations of reef bioconstructors during monitoring activities to assess the vulnerability of CDZ systems to future disturbances and facilitate the adoption of the most appropriate preventative actions

Inventory of the free-living marine nematode species from el Bibane Lagoon (Tunisia)

A detailed inventory of the free-living nematodes of Tunisia has been made for the northern part of Tunisia, but the southern part of the country is unexplored. El Bibane is the second largest lagoon in Tunisia. It is thus of high importance for future conservation actions, but little is known about its biodiversity. In this study, we identified 71 nematode species, belonging to 68 genera and 22 families. Richness was lowest in the central area of the lagoon where the highest percentages of mud and organic matter were found. The number of species detected in this study is high compared to other transitional environments in the Mediterranean basin, but lower than those reported for North Europe. Most of the species are typical of transitional environments or sediments rich in the fine fraction and detritus. The richest families were Cyatholaimidae and Chromadoridae, but the most frequently found species were Xyalidae, Linhomoeidae and Cyatholaimidae. Six of the species collected are new to science, seven are new records for Tunisian waters, and four are new for the Mediterranean basin. This study adds also important information to the biogeography of the phylum because some of the species detected here were previously known only for other geographical regions. Species that currently appear endemic to the Mediterranean Sea include Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer and Metalinhomoeus numidicus. Data published in GBIF (doi:10.15470/wuvqpg

Inventory of the free-living marine nematode species from el Bibane Lagoon (Tunisia)

Inventari de les espècies de nematodes de vida lliure de la llacuna del Bibane (Tunísia) S’ha fet un inventari detallat dels nematodes de vida lliure de la part nord de Tunísia, però la part sud del país està inexplorada. La llacuna del Bibane és la segona més extensa de Tunísia, per la qual cosa té una importància fonamental per al desenvolupament de futures accions de conservació i cal avaluar-ne la biodiversitat. S’hi van trobar 71 espècies de nematodes, pertanyents a 68 gèneres i 22 famílies. La riquesa més baixa es va registrar a la zona central de la llacuna, on es concentren els percentatges més elevats de llot i matèria orgànica. El nombre d’espècies trobades en aquest estudi és alt si es compara amb el d’altres entorns de transició de la conca mediterrània, però més baix que els registrats al nord d’Europa. La major part de les espècies són típiques d’entorns de transició o de sediments rics en fracció fina i detrits. Les famílies més riques van ser Cyatholaimidae i Chromadoridae, però les trobades amb més freqüència van ser Xyalidae, Linhomoeidae i Cyatholaimidae. Cal posar en relleu que sis espècies recol·lectades són noves per a la ciència, set són nous registres en aigües tunisenques i quatre nous registres a la conca mediterrània. Aquest estudi també aporta informació important per a la biogeografia del fílum atès que fins ara algunes de les espècies registrades aquí només eren conegudes en altres regions geogràfiques. Entre les espècies que en aquest moment apareixen com a endèmiques al mar Mediterrani es troben Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer i Metalinhomoeus numidicus. Dades publicades a GBIF (doi:10.15470/wuvqpg)A detailed inventory of the free-living nematodes of Tunisia has been made for the northern part of Tunisia, but the southern part of the country is unexplored. El Bibane is the second largest lagoon in Tunisia. It is thus of high importance for future conservation actions, but little is known about its biodiversity. In this study, we identified 71 nematode species, belonging to 68 genera and 22 families. Richness was lowest in the central area of the lagoon where the highest percentages of mud and organic matter were found. The number of species detected in this study is high compared to other transitional environments in the Mediterranean basin, but lower than those reported for North Europe. Most of the species are typical of transitional environments or sediments rich in the fine fraction and detritus. The richest families were Cyatholaimidae and Chromadoridae, but the most frequently found species were Xyalidae, Linhomoeidae and Cyatholaimidae. Six of the species collected are new to science, seven are new records for Tunisian waters, and four are new for the Mediterranean basin. This study adds also important information to the biogeography of the phylum because some of the species detected here were previously known only for other geographical regions. Species that currently appear endemic to the Mediterranean Sea include Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer and Metalinhomoeus numidicus. Data published in GBIF (doi:10.15470/wuvqpg)Inventario de las especies de nematodos de vida libre de la laguna de El Bibane (Túnez) Se ha realizado un inventario detallado de los nematodos de vida libre de la parte norte de Túnez, pero la parte sur del país está inexplorada. La laguna de El Bibane es la segunda más extensa de Túnez, por lo que su importancia es fundamental para el desarrollo de futuras acciones de conservación y su biodiversidad debe ser evaluada. Se encontraron 71 especies de nematodos, pertenecientes a 68 géneros y 22 familias, registrándose la menor riqueza en la zona central de la laguna, donde se concentran los porcentajes más elevados de lodo y materia orgánica. El número de especies halladas en este estudio es elevado si se compara con el de otros entornos de transición de la cuenca mediterránea, pero más bajo que los registrados en el norte de Europa. La mayor parte de las especies son típicas de entornos de transición o de sedimentos ricos en fracción fina y detritos. Las familias más ricas fueron Cyatholaimidae y Chromadoridae, pero las halladas con mayor frecuencia fueron Xyalidae, Linhomoeidae y Cyatholaimidae. Merece destacarse que seis especies recolectadas son nuevas para la ciencia, siete son nuevos registros en aguas tunecinas y cuatro nuevos registros en la cuenca mediterránea. Este estudio aporta asimismo información importante para la biogeografía del filo puesto que hasta ahora algunas de las especies registradas aquí eran conocidas únicamente en otras regiones geográficas. Entre las especies que en este momento aparecen como endémicas en el mar Mediterráneo se encuentran Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer y Metalinhomoeus numidicus. Datos publicados en GBIF (doi:10.15470/wuvqpg