Diego Lercari

This study examined meiofaunal communities inhabiting sandy beaches, one of the least explored components of marine ecosystems. These organisms occupy the interstitial environment, a habitat highly vulnerable to urban-driven changes and fundamental to multiple ecosystem functions and services in sandy beach systems. The main objective was to assess changes in community structure along the intertidal zones of beaches in the Río de la Plata estuary subjected to different degrees of urbanization. Specifically, the study aimed to characterize meiofaunal assemblages across an urbanization gradient, evaluate correlations with environmental variables, examine seasonal variation, and identify key anthropogenic drivers. Systematic sampling was conducted on six beaches in Montevideo, three located in the urbanized eastern sector and three in the non-urbanized western sector, across seasons and across both upper and lower intertidal zones. The results revealed differences in environmental conditions and community structure between urban and non-urban beaches, including shifts in richness, diversity, and the distribution of dominant and rare taxa. Multivariate analyses confirmed differences in community composition, primarily driven by beach slope, organic matter content, and the degree of urbanization. Urbanization influenced the distribution of meiofaunal taxa, with flatworms and nematodes becoming more dominant on impacted beaches, while tardigrades and crustaceans showed negative responses to urban disturbance. Acari and Cnidaria were exclusive to urban beaches. Overall, the study demonstrates that urbanization alters meiofaunal communities both directly and indirectly, modifying taxonomic composition and diversity in ways that can compromise the broader network of ecological functions and processes supported by meiofauna in estuarine sandy beaches.

The sandy beach isopod Excirolana armata is a widespread intertidal species in the Southwestern Atlantic, occurring across a wide range of environmental conditions. While ecological and genetic evidence suggest population-level divergence along the Uruguayan coast, differences in tolerance to combined environmental stressors remain largely unexplored. This study evaluated the acute survival of E. armata populations from two contrasting sites: an estuarine beach and an oceanic beach. A fully factorial laboratory experiment was conducted, exposing individuals to six salinity levels (0 to 50) and two temperatures (20 °C and 30 °C) during 5 days. Survival probability was modeled using binomial logistic regression with bias correction for complete separation. Our results show that salinity is the primary determinant of survival for both populations, with temperature affecting survival only near optimal salinity levels. Estuarine populations exhibited higher tolerance to low salinity, whereas oceanic populations performed better under high, stable salinities but showed reduced plasticity to low salinities. The observed survival patterns align with the species’ ecological distribution and previously documented genetic structuring, suggesting population-level differentiation associated with local salinity regimes. Salinity acts as a dominant stressor that masks thermal effects, which only emerge under optimal osmotic conditions. Our results underscore the need to account for hierarchical interactions and population-specific responses to accurately assess coastal macrofauna vulnerability to climate change.

Sandy beaches are dynamic ecosystems supporting diverse life forms and remain less explored in terms of biodiversity compared to other coastal systems. Environmental DNA (eDNA) coupled with sequencing technology has emerged as a non-invasive method for assessing biodiversity, particularly in understudied habitats such as sandy beaches. This study employed eDNA metabarcoding on sediments from four Uruguayan beaches (two urban and two rural) using 18S and COI markers to assess the eukaryotic diversity of eDNA found in sandy beaches. Sediments were collected from the intertidal zone, and DNA was extracted. PCR products were then obtained and subsequently sequenced using high-throughput methods. Taxonomic diversity was analyzed at the family level, categorizing molecular operational taxonomic units (MOTUs) into ecological groups (e.g. algae, fungi, benthos). The 18S marker identified 67% of MOTUs, outperforming the COI marker, particularly for algae, fungi, and microbenthos. Algae had the highest diversity (in terms of the number of MOTUs), followed by microbenthos and fungi, while parasites and zooplankton had fewer MOTUs detected. Beaches showed no clear eDNA diversity differences, although site-specific variations in MOTUs abundance were noted. Some taxa, such as harmful algae and pathogens, have both ecological and health significance. These results demonstrate the utility of eDNA in revealing the diversity of sandy beach DNA and detecting taxa of ecological concern. Expanding spatial and taxonomic coverage, increasing the number of samples, and refining methodologies could further enhance our understanding of biodiversity patterns in these ecosystems.

This study explores the prey selection of the invasive gastropod _Rapana venosa_ under controlled laboratory conditions in the Río de la Plata estuary. Under laboratory conditions, the invasive gastropod _Rapana venosa_ consumed more individuals of the clam _Erodona mactroides_ than of the mussel _Mytilus edulis_; although this difference was not statistically significant, _M. edulis_ was consumed in larger biomass quantities. These findings align with optimal foraging theory, emphasizing prey energy profitability and vulnerability. It is important to note that this study constitutes a preliminary exploratory experiment with limited replication, which suggests the need for further research with a higher number of replicates and more varied environmental conditions to draw more robust and generalizable conclusions about the ecological impact of _R. venosa_ in the estuary.

This study investigates the role of stable isotope analysis in unconsolidated sediment coastal systems, focusing on scientific production and research trends over time. Existing literature was analyzed to identify knowledge gaps and highlight the importance of stable isotope techniques in understanding coastal ecosystems. A comprehensive bibliometric analysis was conducted using the Scopus database to collect and categorize relevant publications on stable isotope ecology. Key indicators-including publication trends, authorship patterns, and the geographic distribution of research-are shown. The temporal scope of studies was systematically assessed, with particular attention to methodological approaches employed. Co-authorships networks and co-occurring keywords were examined to explore the intellectual structure of the field and identify collaborative patterns among authors. Over 140 publications were identified, authored by over 400 researchers, with interest increasing significantly over time, particularly in trophic studies involving macrobenthos. Mudflats emerged as a focal point, receiving more attention than sandy beaches. The analysis indicates that seasonality is the predominant temporal scale, while mesoscale studies dominate spatial investigations. A plateau in publication growth appears to coincide with the emergence of alternative methodologies for trophic ecology studies. Major contributions come from France, the United States, and Australia. Co-authorship analysis revealed fragmented collaboration networks, with limited international engagement among developing nations. Overall, the importance of stable isotopes in understanding coastal ecosystems is underscored, while the need for methodological diversity and increased collaboration in future research is highlighted.

This study investigates the role of stable isotope ecology in unconsolidated sediment coastal systems, focusing on scientific production and research trends over time. Existing literature is analyzed to identify knowledge gaps and highlight the significance of stable isotope analysis in understanding coastal ecosystems. A comprehensive bibliometric analysis is employed, utilizing Scopus database to collect and categorize relevant publications on stable isotope ecology. Key indicators are focused on, including publication trends, authorship patterns, and the geographic distribution of research efforts. The temporal scale of studies is systematically analyzed, with attention given to methodological approaches used in these publications. Co-authorships networks and co-occurring keywords are examined to explore the intellectual structure of the field and identify collaborative patterns among authors. Over 140 publications are revealed, attributed to more than 400 researchers, with a significant increase in interest noted over time, particularly in trophic studies involving macrobenthos. Mudflats are identified as a focal point, receiving more attention than sandy beaches. The analysis indicates that seasonality is the predominant temporal scale, while mesoscale studies are observed to be more common in spatial investigations. A plateau in publication growth is noted, probably corresponding with the emergence of alternative methodologies for trophic ecology studies. Major contributions are attributed to France, the United States and Australia. Additionally, fragmented collaboration networks are illustrated through the co-authorship analysis, with limited international engagement among developing nations. Overall, the critical importance of stable isotope ecology in understanding coastal ecosystems is underscored, while the need for methodological diversity and increased collaboration in future research efforts is highlighted.

Dear author, This is an interesting paper on scientific production in Canada, but I think it could be much improved to show scientific soundness and be of some academic use. First, the title does not match the content. It is merely a bibliometric an...

The study of benthic meiofauna has been undertaken in Latin America since the beginning of the 20th century, recently gaining attention due to its recognized role on the ecological functioning of meiofauna assemblages. Bibliometric data provide information regarding research results, explain the degree to which a subject has advanced, and identify its major strengths and weaknesses. In Latin American countries, this type of review is scarce for meiofauna communities. This study analyzes knowledge of marine meiofauna by focusing on the documents Latin American authors published from 1990 to 2021. Documents from three bibliographic databases were analyzed to obtain the most relevant bibliometric indicators. Moreover, the interrelationships between authors, countries, and concepts were analyzed using science mapping techniques. Latin American research on marine meiofauna has increased since the 1990s, producing a total of 399 documents over three decades by almost 1,000 authors. Brazil produced the majority of these documents (predominantly published by Brazilian authors and institutions). The number of documents by country was associated with five development indicators. Their main sources and keywords indicate that ecology, oceanography, and biogeography were the main addressed topics, especially on deep marine environments. Most productive authors were clustered into main research groups with varying degrees of links. We conclude that research efforts on marine meiofauna are gaining importance despite the small number of documents by a relatively low number of research groups. We found a high centralization of documents by countries and a relation with four indicators, such as country size and research spending. Greater regional collaboration could further expand the knowledge of marine meiofauna in Latin America.