1,720,977 research outputs found
Diatoms as bioindicators for health assessments of ephemeral freshwater ecosystems: A comprehensive review
No full textEphemeral waters (EW) are sensitive and vulnerable ecosystems that, although the numerous ecosystem services provided, are poorly investigated and properly managed. Diatoms represent an important biological model largely used in aquatic permanent habitats but underused in ephemeral waters. The aim of this review is to address the knowledge gap, examining the current state of knowledge regarding the health of EW, with a focus on diatoms as bioindicators, specially (i) presenting research trends on EW ecosystem types investigated (ii) analysing the methodological approach, (iii) providing the influence of abiotic factors on the diatom assemblages in EW. A bibliographic search yielded a total of 512 papers. After removing duplicate records, 118 were eliminated. The screening of abstracts resulted in the selection of 48 articles on diatoms and EW since 1982. To avoid discrepancy between terminology we decided to classify the EW found in 3 different categories: Intermittent Running Waters (IRW: rivers, streams, creek, springs), Temporary Large Wetlands (TLW: wetlands, lakes, lagoons) and Temporary Small Waters (TSW: ponds, pools, ventaroles, ditches, thermal waters, troughs, pans). Studies are reported in all continents including Antarctic. IRW are the most investigated ecosystem (n = 683), followed by TSW (239) and TLW (96). Furthermore, studies were mainly conducted on sites located below 1000 m a.s.l. of altitude (n = 27). Studies mainly focus on epilithic diatoms (52 %). Electrical conductivity (80 %), pH (77 %) and water temperature (75 %) are the principal physical-chemical parameters considered. Moreover, electrical conductivity, pH, temperature, nitrate and nitrite resulted the best diatom community drivers. Future research is encouraged (1) to achieve a standardised protocol for monitoring EW using diatoms, (2) to focus on conservation projects for high-altitude temporary waters, and (3) to investigate the main driving forces influencing diatom diversity on EW
New ecological frontiers in the plastisphere: Diatoms and macroinvertebrates turnover assessment by a traits-based approach
No full textTo date, there are very few studies regarding the colonization of artificial substrates in wetlands by macroinvertebrates and diatoms and even fewer are the studies in Italy that take into consideration the diatomic guilds and the biological and ecological traits proposed in literature. Wetlands are at the forefront through the most delicate and threatened freshwater ecosystems. In this study, we want to evaluate the colonization capacity of plastics of diatoms and macroinvertebrates and characterize the diatomic and macroinvertebrate communities using a “traits-based” approach focusing on the colonization of virgin substrates made of polystyrene and polyethylene terephthalate. The study was conducted within the ‘Torre Flavia wetland Special Protection Area’ a protected wetland area in Central Italy. The study was conducted from November 2019 to August 2020. The results obtained in this study show a tendency of diatom species to colonize artificial plastic supports placed in lentic environments without differences related to the plastic type and water depth. There is also a greater number of species belonging to the “Motile” guild, endowed with a high motility that they exploit to search for more ecologically suitable habitats for settlement. Macroinvertebrates, prefer settlement on polystyrene supports, those on the surface, probably due to the anoxic conditions present on the bottom and the physical structure of the polystyrene that provides shelter to many animal taxa. The analysis on traits highlighted the establishment of an ecologically diverse community mainly formed by univoltine organisms, with dimensions between 5 and 20 mm, predators, choppers and scrapers feeding on plant organisms and animals, but without the formation of a clear ecological system, that is, without evidence of ecological relationships established between two or more taxa. Our research can contribute to underline the ecological complexity of biota inhabiting plastic litter in freshwaters and the implications for plastic-impacted ecosystems biodiversity enrichment
Diatom and macroinvertebrate communities dynamic: A co-occurrence pattern analysis on plastic substrates
No full textWetlands are habitats that provide numerous ecosystem services, but are often understudied and threatened by anthropogenic pollution, particularly plastic pollution. Macroplastics are a significant component of plastic litter that have high biological impacts but are often understudied. Previous studies have highlighted negative impacts on biota, but there is a lack of information about the communities of micro and macro organisms that settle on macroplastic litter. In this context, we investigated the colonization patterns and community structures of di-atoms and macroinvertebrates on virgin substrates composed of two different plastic polymers, polystyrene and polyethylene terephthalate, located at two different depths in a protected wetland in Central Italy over a period of 10 months. The results show that diatom community is not highly structured by competitive forces and ag-gregation patterns emerges. In contrast, macroinvertebrate community appears to be randomly structured, without the presence of patterns following specific assembly rules. Randomness in macroinvertebrates assem-blages could highlight the presence of different niches available for settlement of different taxa. Combined matrix analyses show that diatoms and macroinvertebrates co-occur, and their community assemblages are sometimes structured, while they appeared to be randomly assembled at other times. Whenever non-randomness of diatoms and macroinvertebrates co-occurrences was detected, it suggested aggregation. Moreover, the possible predatory relationship between different macroinvertebrates taxa should be investigated, as it could reveal important scenarios in the establishment of macroinvertebrate structured communities on plastic litter, including taxa that exploit different ecological niches. This could lead to an enrichment of the biological community within areas impacted by plastics
Testing effectiveness in nature reserve management using GIS-based tools: a 25 years monitoring of land use change in a Mediterranean coastal wetland
No full textLand-cover change dynamics were investigated in a Mediterranean coastal wetland to evaluate the long-term effectiveness of nature reserve management. A multitemporal analysis of land cover maps was conducted, utilizing visual interpretation of aerial orthophotos from the summer seasons of 1996, 2008, 2015, and 2021. Landscape changes were evaluated by transition matrices and chord diagrams. Maps were classified in accordance with CORINE land cover types at a fourth level of detail. The multitemporal analyses provided a comprehensive overview of landscape changes within the reserve over the past 25 years. The most notable changes were the increase of wetland areas and the reduction of agricultural and artificial areas. Moreover, seminatural vegetation constantly extended over time. These changes reflected the continuous management activities within the nature reserve, encompassing agreements for water supply, restoration projects, and measures to counteract illegality. These operational actions induced fine-grained ecological changes (outcomes at ecosystem level). This study highlighted the importance of remote sensing and landscape analysis, matched with fine-grained management data, as tool for long-term monitoring. Such an approach provides valuable support in evaluating the effectiveness of strategies promoted in nature reserves hosting wet coastal ecosystems of high conservation concern
Is the weight of plastic litter correlated with vegetal wrack? A case study from a Central Italian beach
No full textNon-native Corbicula fluminea (Müller, 1774) (Bivalvia, Veneroidea) in Central Italy: do the waters pumped by Reclaimed Agencies may have a role in spreading through translocation?
Full text linkAsian clam, Corbicula fluminea, is an invasive mollusk species (Bivalvia, Veneridae) known to cause several negative impacts in freshwater ecosystems where it has been introduced. In the 2022 summer season a total drying up took place in the “Torre Flavia” wetland, a Special Protection Area (Latium, central Italy): it made possible a survey of biological remains deposited in the bottom of the wetland channels (> 2,000 m in total length). During this survey, for the first time, we recorded valves belonging to 68 specimens of Asian clam. We did not record living specimens. This is the first case of occurrence of this mollusk in a wetland basin (the fourth record for Central Italy). The population would not appear to have naturalized locally but, probably, individuals could be accidental arrived by the waters pumped by the Reclaimed Agency. We discussed the implications about the role of these Agencies in favour involuntarily the translocation of both native and non-native species from the dewatering pumps (along the Tiber River) to surrounding land reclaimed wet areas (channels and swamps) and croplands connected to the artificial water system
Hydra vulgaris assay as environmental assessment tool for ecotoxicology in freshwaters: a review
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Epiplastic microhabitats for epibenthic organisms: a new inland water frontier for diatoms
No full textPlastic pollution is widespread in each type of ecosystems. However, the colonization events of microorganisms on plastics seem to be neglected in inland waters. Therefore, in this study we analyze the possible colonization on the surface (hereafter epiplastic microhabitats) of two typology of plastic supports by diatom community. Specifically, we located 20 supports in expanded polystyrene and 20 in polyethylene terephthalate both floating and dipped (~ 1 m) in a central Italian shallow water pond, in order to evaluate the diachronic colonization of diatoms from November 2019 to August 2020. Our result showed the tendency in colonizing both epiplastic microhabitats without significant differences in number of species; additionally, depth does not appear to affect the number of species. As regard the temporal colonization, the number of species tends to increase over time from autumn-winter to spring-summer in both types of epiplastic microhabitats and depth. Instead, increase in dominance of some species over time has been demonstrated: only a few species keep a high number of individuals compared to the others; therefore, the number of individuals within the species is not uniformly distributed. These results suggest the tendency of diatom community to colonize plastic supports in lentic waters, and this evidence can be very important because artificial supports can increase the surface available for the settlement of the algae community with an increase of productivity and the colonization of new communities of different taxa. Further studies are mandatory to investigate the possible effects on the epiplastic community and the ecological implications in freshwater environments. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11356-022-23335-8
Microplastics, Additives, and Plasticizers in Freshwater Bivalves: Preliminary Research of Biomonitoring
Full text linkMicroplastics are widespread in freshwater environments and could impact these ecosystems. Bivalves are freshwater organisms that are particularly exposed to microplastic contamination. Therefore, in this preliminary study, the accumulation of microplastics, plasticizers, and additives in the freshwater bivalves Anodonta cygnea was investigated through active biomonitoring. Specimens bought commercially were exposed in three rivers in Central Italy for different exposure times: short (1 month) and long (3 months). The gills and the gastrointestinal tract (GIT) were analyzed separately to evaluate the possible uptake and ingestion of particles via Micro-FTIR. For the first time, small microplastics (SMPs, 5–100 μm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs), were identified in the bivalve A. cygnea. The most abundant polymer in the gills (94.4%) and in the GITs (66.1%) was polyamide, which had the highest concentration in each river. A decrease in SMPs’ abundance was observed over time in the gills in each river, while the abundance in the GIT increased. Compared to polymers, a greater variety of APFs was observed in rivers. The APFs changed during the time of exposure and between different rivers more evidently than polymers, allowing for a clearer identification of the possible sources. These results highlighted the plastic pollution caused by SMPs using freshwater bivalves as sentinel organisms and the need to further investigate the additives that can be proxies of the presence of microplastics in the environment and biot
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