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10.1038/s41467-023-36241-5 7 Lomartire S., Marques J.C., Gonçalves A.M.M. The key role of zooplankton in ecosystem services: A perspective of interaction between zooplankton and fish recruitment. Marine ecosystems, from coastal areas to open waters, teem with a multitude of heterotrophic and mixotrophic organisms collectively forming the zooplankton, the animal component of the plankton. The authors find significant changes in the mesozooplankton community structure and copepod assemblages in the upwelling cold dome region, formed by the Kuroshio Current intrusion in the Southeast China Sea during the southwest monsoon. However, parasitized copepods are mainly females rather than males and juveniles, and the highest percentage of infected copepods is observed in the winter and summer seasons of different years. [Extracted from the article]

Molecular tools increasingly refine and improve the identification of zooplankton organisms based on phenotypic features, providing a more robust and comprehensive species description. Integration of data helps revealing the hidden diversity of zooplankton and facilitating the detection of rare and non‐indigenous species. This approach, merging morphological characters and a diagnostic marker for specific identification, such as the mitochondrial cytochrome c oxidase I (COI), is here used to characterize key taxa from the zooplankton assemblage of the Gulf of Naples at the Long‐Term Ecological Research site MareChiara (LTER‐MC) (Central Tyrrhenian Sea, Western Mediterranean Sea). Zooplankton biodiversity assessment using integrated taxonomy was focused on selected crustacean groups: cyclopod copepods (Agetus typicus, Oithona plumifera, Oncaea mediterranea, Oncaea scottodicarloi); newly records of cladocerans (Evadne nordmanni), euphausiids (Euphausia krohnii, Nematoscelis megalops, Nyctiphanes spp.) and sergestids (Lucifer typus), with the aim to boost the knowledge of real zooplankton biodiversity. The results of our investigation provide new high‐quality molecular references of the analysed taxa and contribute to unveiling the genetic diversification of zooplankton species and their relevant ecological significance for Mediterranean coastal waters. [ABSTRACT FROM AUTHOR]

Long‐term ecological research has revealed the impact of climate on marine ecosystems at multiple time scales. Changes in the pelagic system have been detected at the LTER‐MC site in the Gulf of Naples (Tyrrhenian Sea, western Mediterranean) since 1984. Here we analyzed the time series to determine whether zooplankton had significantly changed over the three decades 1984–2015. In addition to the seasonal cycle as the main mode of temporal variability, we observed long‐term trends in the functional groups and species. Copepods, the most abundant group, declined over the years owing to a decrease in the abundance of Acartia clausi, Centropages typicus, the Paracalanus parvus complex, and Oithona spp. Increasing trends were observed for strict carnivores (chaetognaths) and typical filter feeders (cladocerans, appendicularians, and thaliaceans); the latter may be linked to a higher density of <5 μm phytoplankton. Two main temporal shifts were detected: (i) in 1985–87, similarly to the regime shifts registered in other basins of the Northern Hemisphere, and (ii) after 2011, likely related to local atmospheric forcing. The disappearance or decrease in some neritic copepods and the increased abundance of typical offshore species seem to reflect the enhanced influence of the open Tyrrhenian waters at the sampling site. Despite these changes, no significant trends were detected in the total zooplankton abundance and overall composition, which indicates restructuring within the whole community. These results underline the need to examine the entire zooplankton diversity spectrum and improve our knowledge of their ecological traits to detect and interpret long‐term variability. [ABSTRACT FROM AUTHOR]

Centropages typicus is a temperate calanoid copepod occurring in Atlantic and Mediterranean coastal waters, where its reproductive biology and population dynamics are well‐known. C. typicus has also been suggested as a key species for monitoring the impact of environmental changes on copepod secondary production. The aim of this study is to investigate the seasonal and interannual reproductive (egg production and egg hatching success) and feeding (fecal pellet production) traits, population abundance and structure (sex ratio) of C. typicus over a 20‐year period at the Long‐Term Ecological Research site MareChiara (LTER‐MC) in the Gulf of Naples (Central Tyrrhenian Sea, Western Mediterranean Sea), identifying specific trends and patterns. At a seasonal scale, egg production and hatching success were tightly linked with maxima in February–March, driving the juvenile and adult springtime population peaks but showing a poor correlation with phytoplankton abundance, pointing to an omnivorous diet. At a multiannual scale, an observed decrease in the population is backed up by a reduction in egg production, despite an increase in hatching success. The results of this study provide new elements to comprehend the links between C. typicus functional traits, population dynamics, and environmental factors and highlight the importance of running LTER series to monitor the trends in natural environments. [ABSTRACT FROM AUTHOR]

Among non-native copepods, the calanoid Pseudodiaptomus marinus Sato, 1913 is the species probably spreading at the fastest pace in European and neighbouring waters since its first record in the Adriatic Sea in 2007. In this contribution, we provide an update on the distribution of P. marinus in the Mediterranean and Black Seas, along the Atlantic coasts of Europe, in the English Channel and in the southern North Sea. Starting from a previous distribution overview, we include here original and recently (2019–2023) published data to show the novel introduction of this species in different geographical areas, and its secondary spreading in already colonised regions. The picture drawn in this work confirms the strong ability of P. marinus to settle in environments characterised by extremely diverse abiotic conditions, and to take advantage of different vectors of introduction. The data presented allow speculations on realistic future introductions of P. marinus and on the potential extension of its distribution range. [ABSTRACT FROM AUTHOR]

Over the last decade, the calanoid copepod Pseudodiaptomus marinus--native to the Indian Ocean--has rapidly spread throughout the European Seas. Here we report its first occurrence in the southern Levantine Sea. Zooplankton samples were collected monthly by vertical net hauls in a coastal monitoring station at the Israeli Mediterranean Sea during 2019-2021. The samples were analyzed using mitochondrial COI and 18S rRNA metabarcoding, revealing the occurrence of P. marinus in winter and spring. Following the molecular detection, two individuals of P. marinus were observed in the samples and identified morphologically, indicating a low population abundance (0.4 ind. m-3) and confirming its status as widespread but rare, as reported in former colonized areas. Rare species often go undetected in zooplankton assemblages using morphological examination, whereas DNA metabarcoding is a sensitive, rapid, and cost-effective method that can provide valuable presence/absence data of such species. We further show that the use of both mitochondrial and nuclear gene markers provides a robust and comprehensive non-indigenous species (NIS) early-detection system, and stress that combining DNA metabarcoding with morphological examination is necessary for biodiversity monitoring in marine ecosystems that undergo significant transformations due to climate and/or anthropogenic forcing. [ABSTRACT FROM AUTHOR]

Single nucleotide polymorphism (SNP) markers in anchovy (Engraulis encrasicolus) egg samples were analysed to detect their origin on a small spatial scale (200 km) by assigning genotypes to adult anchovy stocks. The novelty of this work is the application of a rapid high‐throughput method for genotyping each single anchovy egg, in a single execution, using a set of 96 genome‐wide SNPs in a dynamic array system with microfluidic technology (Fluidigm 96.96).The existence of two ecotypes in E. encrasicolus had already been identified based on SNP polymorphism in the Atlantic Ocean and in the Mediterranean Sea, showing that habitat type (offshore versus coastal/estuarine) is the most important component of genetic differentiation among populations of anchovy.In this work, anchovy egg genotypes from areas of the Western Mediterranean were assigned to adult populations. Only two localities in which adult anchovies were sampled represented donor populations for the coastal/estuarine egg genotypes. Although some degree of mixing among the hauls could exist, the assignment of egg groups to adult populations led to distinguishing the contributions of distinct ecotypes to new wild generations. We can conclude that the high rate of egg dispersion caused by marine currents and the different degrees of local retention could explain the genetic heterogeneity observed in the adult populations, where eggs from neighbouring spawning sites tend to mix.The results highlight that this technique represents a new and useful tool for addressing evolutionary questions, breed recognition, assignment, and connectivity assessment of individual eggs, and anchovy population dynamics, for the management of stocks. [ABSTRACT FROM AUTHOR]

Salps (pelagic tunicates) are rarely observed in nature and trophic interactions involving them mainly rely on the inspection of stomach contents of their potential predators. Moreover, salps have soft bodies that are hardly identified in potential consumers. We involved recreational SCUBA-divers and photographers in collecting de visu evidence of i) massive occurrence of salps and ii) trophic interactions involving salps as preys and benthic animals as consumers. Direct evidence of trophic interactions between salps and benthic fish was documented by photographic frames. We detected a long colony of the salp Pegea confaederata being transported by currents close to the substrate on top of Banco di Santa Croce, an underwater rocky outcrop in the Gulf of Naples (Italy). An individual of the rainbow wrasse Coris julis attacked the above-mentioned salp colony by selectively detaching individuals and biting their stomach. Our report of a trophic interaction between labrids and salps is the second in fifty years and the previous one was only indirect. In this study, citizen science allowed detecting both neglected marine animals like salps and trophic interactions involving them. Visual, direct evidence of predation on salps by benthic fish adds further knowledge about patterns of living-matter fluxes between plankton and benthos, opening new questions on the potential of global change in modifying the efficient circulation of organic matter in marine systems. [ABSTRACT FROM AUTHOR]

Copepods belonging to the Oncaeidae family are commonly and abundantly found in marine zooplankton. In the Mediterranean Sea, forty-seven oncaeid species occur, of which eleven in the Gulf of Naples. In this Gulf, several Oncaea species were morphologically analysed and described at the end of the XIX century by W. Giesbrecht. In the same area, oncaeids are being investigated over seasonal and inter-annual scales at the long-term coastal station LTER-MC. In the present work, we identified six oncaeid species using the nuclear ribosomal internal transcribed spacers (ITS rDNA) and the mitochondrial cytochrome c oxidase subunit I (mtCOI). Phylogenetic analyses based on these two genomic regions validated the sisterhood of the genera Triconia and the Oncaea sensu stricto. ITS1 and ITS2 phylogenies produced incongruent results about the position of Oncaea curta, calling for further investigations on this species. We also characterised the ITS2 region by secondary structure predictions and found that all the sequences analysed presented the distinct eukaryotic hallmarks. A Compensatory Base Change search corroborated the close relationship between O. venusta and O. curta and between O. media and O. venusta already identified by ITS phylogenies. The present results, which stem from the integration of molecular and morphological taxonomy, represent an encouraging step towards an improved knowledge of copepod biodiversity: The two complementary approaches, when applied to long-term copepod monitoring, will also help to better understanding their genetic variations and ecological niches of co-occurring species. [ABSTRACT FROM AUTHOR]

The internal organization of plankton communities plays a key role in biogeochemical cycles and in the functioning of aquatic ecosystems. In this study, the structure of a marine plankton community (including both unicellular and multicellular organisms) was inferred by applying an ecological network approach to species abundances observed weekly at the long-term ecological research station MareChiara (LTER-MC) in the Gulf of Naples (Tyrrhenian Sea, Mediterranean Sea) in the summers of 2002-2009. Two distinct conditions, characterized by different combination of salinity and chlorophyll values, alternated at the site: one influenced by coastal waters, herein named 'green', and the other reflecting more offshore conditions, named 'blue'. The green and blue 'phases' showed different keystone biological elements: namely, large diatoms and small-sized flagellates, respectively. Several correlations amongst species belonging to different trophic groups were found in both phases (connectance ~0.30). In the green phase, several links between phytoplankton and mesozooplankton and within the latter were detected, suggesting matter flow from microbes up to carnivorous zooplankton. A microbial-loop-like sub-web, including mixo- and heterotrophic dinoflagellates and ciliates, was present in the green phase, but it was relatively more important in the blue phase. The latter observation suggests a more intense cycling of matter at the microbial trophic level in the blue phase. These results show that different modes of ecological organization can emerge from relatively small changes in the composition of aquatic communities coping with environmental variability. This highlights a significant plasticity in the internal structure of plankton webs, which should be taken into account in predictions of the potential effects of climatic oscillations on aquatic ecosystems and biogeochemical cycles therein. [ABSTRACT FROM AUTHOR]

Three species of Oncaeidae, Triconia umerus, T. hawii and T. rufa are reported for the first time in the coastal waters of the Gulf of Naples, Tyrrhenian Sea, western Mediterranean Sea. They were found in meso-zooplankton samples collected in 2004 and were absent from samples collected prior to 2004. Specimens of Triconia umerus and T. hawii were compared with material collected from the type locality (the Red Sea). In order to facilitate identification, brief differential diagnoses, supported by scanning electron micrographs, are presented for the five species of Triconia that have small body size (450 to 600 μm) and co-occur in the upper 50 m of the water column of the Gulf of Naples. Surface ornamentation on the genital double-somite of the female is reported in T. minuta and T. hawii for the first time, but it is difficult to observe using light microscopy and we infer that it has probably been overlooked in these species hitherto. Possible explanations for the new discovery of these species in such a well-studied area are discussed and it is suggested that they represent relatively recent additions to the fauna. A key to the eleven species of Oncaeidae found in the Gulf of Naples is presented. [ABSTRACT FROM PUBLISHER]

The population structure (NI to adults) of the copepods Centropages typicus and Temora stylifera was investigated in parallel at two sites in the eutrophic and oligotrophic waters of the Gulf of Naples (Tyrrhenian Sea) with the aim of identifying the environmental factors that modulate the occurrence of these calanoids that are abundant in the neritic waters of the Mediterranean Sea. Monthly zooplankton sampling was conducted from May 1999 to June 2000 in 5–7 discrete depth layers in the upper 200 m with a 70-μm mesh net. Temperature, salinity, and fluorescence profiles were recorded by CTD casts. The remarkable differences observed in the temporal and spatial patterns of the two populations throughout their developmental cycles seem to result more from different responses to environmental factors than from different life-history traits. C. typicus was abundant in early to mid-summer and was distributed in the whole water column; T. stylifera followed in late summer–autumn and occurred preferentially in the upper 30 m. Temperature was the main regulating factor for T. stylifera. The availability of autotrophic food appeared relatively more important for C. typicus, although unequivocal signals were not observed, suggesting that more complex trophic interactions likely affect the dynamics of the two populations. [Copyright &y& Elsevier]

Nowadays, ENMs/NPLs particles have not yet been extensively measured in the environment, but there is increased concern that this size fraction may be more widely distributed and hazardous than larger-sized particles. This study aimed to examine the bioaccumulation potential of engineered nanomaterials and nanoplastics (ENMs/NPLs) across marine food webs, focusing on plankton communities and commercial fish species (Engraulis encrasicolus and Scomber colias) from the Gulf of Naples. Laboratory experiments on plankton assemblages exposed to fluorescent polystyrene nanoplastics (PS-NPs, 100 nm) for 24h at concentrations ranging from 0.01 to 10 mg/L confirmed nanoplastic uptake in phytoplankton and zooplankton, indicating a dose-dependent internalization in plankton communities. Notably, in natural samples no particles were detected in fish muscle or liver tissues, suggesting limited translocation. Unexpectedly, titanium oxide particles (<1 μm) were found in natural phytoplankton, highlighting the potential presence of other nanoparticles in marine systems. These findings suggest that, despite detection challenges, plankton communities are major biosensors of ENMs/NPs contamination and highlight the need for ongoing environmental monitoring to assess ecological impacts and potential risks of nanoparticle bioaccumulation in marine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Anchovies represent the largest world's marine fish catches and the current threats on their populations impose a sustainable exploitment based on sound scientific information. In the European anchovy (Engraulis encrasicolus), the existence of several populations has been proposed but a global view is missing. Using a multidisciplinary approach, here we assessed the divergence among different ecotypes and its possible causes. SNPs have revealed two functionally distinct ecotypes overlapping in the Central Mediterranean, with one ecotype confined near the river estuaries. The same SNPs outliers also segregated two distinct populations in the near Atlantic, despite their large spatial distance. In addition, while most studies suggested that adaptation to low salinity is key to divergence, here we show that the offshore ecotype has higher environmental tolerance and an opportunistic feeding behaviour, as assessed by the study of environmental conditions, anchovy diet and trophic levels, and passive egg dispersal. These results provide insights into the anchovy evolutionary history, stressing the importance of behaviour in shaping ecotypes.