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The aim of this study was to conduct a systematic review of the scientific literature on aquatic ecosystem services. We used the Web of Science database for our research. We found a total of 1,367 articles, with 837 papers that studied ecosystem services provided through the interaction between terrestrial and aquatic environments (terrestrial–aquatic papers) and 530 papers relating only to aquatic environments. Despite the growing number of articles, there is still less research on aquatic environments compared to terrestrial environments. We found a correlation between types of services and taxonomic groups, such that supporting ecosystem services were investigated using mainly macroinvertebrate, microorganisms and aquatic macrophytes communities, while provisioning and cultural ecosystem services were frequently studied with fishes. The analysis of keywords revealed that there was a temporal shift in the terms studied, and some words presented a higher frequency in aquatic research. Nonetheless, other words appeared in aquatic and terrestrial–aquatic studies with similar frequencies. The trends and biases detected in the present paper can help us to understand the role of aquatic biodiversity in ecosystem services more fully in the future as well as assist in the creation of strategies for future studies on the conservation of these services. [ABSTRACT FROM AUTHOR]

The feeding upon large animals—even larger than the predator—by benthic cnidarians has been reported from many ecosystems but never exhaustively studied to date. By reviewing 38 papers on this topic, this review aims to recap the observations on the predatory behaviour of polyps, to establish feeding plasticity boundaries and to understand the contribute of this trophic strategy to the benthic–pelagic coupling. The reviewed documents published increasingly during the last two decades mostly reported observations on heterotrophic Anthozoa in shallow ecosystems collected through photo/video records. The main prey items are represented by gelatinous zooplankton and echinoderms. The lexical discordance in the considered papers highlights the need to standardize the terminology to describe the feeding behaviour of benthic Cnidaria, opportunistic and characterized by a strong plasticity. Given the importance of large prey in cnidarian trophism, we proposed an unambiguous terminology that will help the online search of literature and address future studies. We suggest identifying micro-predation (predator/prey size ratio ≥ 5:1) and macro-predation (predator/prey size ratio is ≤ 1:1) as distinct feeding modalities, because the capture of large prey involves peculiar movements of polyps, such as stretching and retracting of column and tentacles to pull the prey towards the mouth. [ABSTRACT FROM AUTHOR]

Stygobionts, namely animals with strong adaptations to subterranean environments that are unable to complete their life cycles outside groundwater, can be observed in spring ecotones, but their occurrence is generally considered accidental. The aim of this paper is to assess if stygobiont occurrence in springs is linked to specific environmental conditions or if it is random, irrespective of their features. For three years, we surveyed 59 spring sites recording the occurrence of vertebrate and invertebrate stygobiont species and assessing if spring features were related to their distribution. Moreover, we recorded the escape reactions of two easily identifiable stygobiont species. We detected six taxa usually considered as strictly stygobiont based on their troglomorphic features. Two of them were quite widespread: the salamander Proteus anguinus and the shrimp Troglocaris planinensis. Environmental characteristics were significantly related to the distribution of stygobionts. Hydroperiod and occurrence of flooding were the factors that played the strongest role in affecting occurrence. Our study suggests that the occurrence of stygobionts in springs is linked to specific habitat features rather than being a random mechanism and that the exploitation of ecotones can be important for the lifecycle of some species usually assumed to be strictly associated to caves. [ABSTRACT FROM AUTHOR]

Adaptation to different ecological niches is considered one of the main drivers of species diversification, also in cryptic species complexes, notwithstanding their morphological stasis. We here review all the published information on ecological differentiation within cryptic species complexes within the phylum Rotifera. We found 177 instances of cryptic species identified genetically, published in 101 papers. Only a subset of the papers contained available information on ecological differences and only for two of the 54 known complexes, namely Brachionus calyciflorus s.l. and Brachionus plicatilis s.l., sufficient data were available for analyses of ecological differences. For the B. calyciflorus complex, B. fernandoi consistently occurred at a significantly lower temperature than the other species in the complex; no differences were found for other environmental variables. For the B. plicatilis complex, B. paranguensis occurred in waters with higher pH than the other species; no differences were found for other environmental variables. These results, even if preliminary and based on scattered information, reveal that adaptation to different ecological niches exists also between closely related species. Our aim is to showcase this interesting field of research spurring further detailed studies to focus on the mechanisms of ecological speciation using rotifer cryptic species as a model system. [ABSTRACT FROM AUTHOR]

Most information on rotifers living in lake sands comes from the 1930s, when the first reports on this subject by Jerzy Wiszniewski appeared. After some decline in the interest in lake psammon in the following years, research on lake psammon returned in the last decade of the twentieth century. The last comprehensive review of ecology of psammon Rotifera was included in the excellent 1998 publication by Schmid-Araya on Rotifera in interstitial sediments. More than 20 papers have been published since that time. So far, research conducted almost exclusively in the northern hemisphere have dealt with issues related to distribution of rotifers, their species structure and diversity as well as to their relation to abiotic and biotic factors. The aim of the present study was to collect all available information on psammon rotifers, assess the shortcomings in our knowledge and fill these gaps with the results of some of my recent research. The results of the study show that the species richness of this group in geographical terms is still unknown. It means we also do not know the level of endemism among the psammon rotifers. The role of psammon rotifers in benthic food webs is another issue requiring research. [ABSTRACT FROM AUTHOR]

Studies on zooplankton in lakes, ponds, and rivers have always received more attention, while zooplankton from streams remains understudied worldwide. Therefore, the role of zooplankton in neotropical stream functioning is still poorly understood. In order to remedy this situation, we aimed to answer the following questions: (1) How many papers have been published on the zooplankton from Brazilian streams? (2) In which hydrographic regions were these studies conducted? (3) Are there specific patterns of zooplankton species occurrence in neotropical streams? (4) What are the main types of studies and what are the main environmental factors influencing zooplankton in streams? In order to answer these questions, we performed a systematic review of indexed scientific papers. We indeed observed a paucity of studies on zooplankton in Brazilian streams. But despite the low number of studies (24), many species (276 taxa) were reported from seven Brazilian hydrographic regions. The species composition showed great variability within the hydrographic regions and fourteen environmental variables (physical, chemical, and spatial), which can represent environmental filters and influence dispersion processes, were related to zooplankton occurrences. These bibliographic data helped to clarify patterns in species composition and community structure of zooplankton in these streams. More studies are needed to further investigate the role of zooplankton in neotropical streams, which can help to develop conservation strategies. [ABSTRACT FROM AUTHOR]

The editorial in Hydrobiologia discusses the importance of studying functional traits in macrophytes to understand their adaptations and responses to ecological drivers. The paper highlights the need for functional trait ecology to bridge knowledge gaps and address the global crisis of vanishing macrophytes. Various studies presented in the editorial explore the impact of light quality, individual-level functional diversity, alien macrophytes, and intraspecific trait variation in different ecosystems, providing valuable insights for ecological management. The research emphasizes the significance of investigating macrophyte functional traits to enhance our understanding of freshwater ecosystems and the services they provide. [Extracted from the article]

This document is a preface to a special issue of the journal Hydrobiologia on the topic of stream ecology and environmental gradients. The preface explains that human activities have fragmented natural landscapes, leading to changes in environmental gradients and a decline in biodiversity. The document highlights the importance of understanding the effects of environmental gradients on aquatic communities and ecosystem services. The special issue includes 10 papers from authors of various nationalities, focusing on the effects of land use, vegetation cover, water pollution, and other disturbances on diatoms, macroinvertebrates, and fish communities. The studies demonstrate that environmental gradients can alter water quality, habitat availability, and the structure and composition of aquatic communities. The document concludes by expressing gratitude to the reviewers and authors who contributed to the special issue. [Extracted from the article]

The fourth one focused on the microbiome of an ostracod (Arthropoda, Crustacea) species, reporting that it was different from the known microbiomes of other freshwater ostracods, but had large variability even among ostracod individuals from the same population. Guest editors: Isa Schön, Diego Fontaneto & Elena L. Peredo / Aquatic Microbiomes The holobiont approach (Bosch & Miller, [2]) in the study of animal ecology places strong emphasis on the strict association between the animals and their microbes, which are beneficial for the host's survival and fitness (Cornwallis et al., [3]). The other paper compared the hindgut microbiome of two fish (Chordata, Actinopterygii) species in an African lake showing that the two fish species had different diets, but not different microbiomes. [Extracted from the article]

Invasion of non-native fishes threatens freshwater biodiversity worldwide. Yet, detailed estimates of population demography for invasive species, such as population size and body size, are rarely integrated in evaluating aquatic community responses. Our study capitalised on detailed brook trout population demographic data collected for a replicated whole lake ecosystem experiment involving experimental harvesting of exotic brook trout in nine mountain lakes. We applied environmental DNA (eDNA) metabarcoding and morphological taxonomy to examine the response of crustacean zooplankton and macroinvertebrate communities to gradients in brook trout effective density and lake elevation. Density-dependent effects of brook trout on crustacean zooplankton and macroinvertebrate communities were detected even decades after their first introductions (between 1926 & 1980). However, they were moderated by environmental factors such as elevation, lake maximum depth and dissolved organic carbon. Elevation was important in structuring crustacean zooplankton and macroinvertebrate community composition. While there were differences in explanatory variables when describing communities characterized by eDNA metabarcoding and morphological taxonomy, the principal environmental factors that structured the communities were similar. Our paper highlights persisting density-dependent impacts of exotic trout on invertebrate communities even decades after first introduction, and it considers the conservation implications for lake restoration. [ABSTRACT FROM AUTHOR]

This paper introduces and summarises the main outcomes of the 19th workshop of the International Association for Phytoplankton Taxonomy and Ecology held in Tiszafüred, Hungary, Tisza Balneum Hotel, from 23 to 30 September 2022. The selected theme of the workshop was "Trait-Based Approaches in Micro-Algal Ecology". The discussions presented during the workshop sessions resulted in the 18 articles contained in this Special Issue. There are 6 main thematic aspects developed by the participants: 1. Shape and size: are these traits easy to measure? 2. Spatial scales: when and where to look for microalgae? 3. Climate and extremes of ecological gradients: hot topics of this century. 4. Metaphyton and metaphytic habitats: life beyond plankton and benthos. 5. Microalgae in water management: phycology in practice. 6. Traditional and new methods: perspectives and comments. Trait-based approaches in microalgae ecology, although requiring further investigation and methodological development, represent a valid tool for refining the analysis of environmental variability in aquatic ecosystems. The papers presented in this Special Issue demonstrate that these approaches are extremely useful not only in the study of planktic algae but constitute a thoughtful method for the analysis of benthic and metaphytic microalgae in a wide variety of aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of phytoplankton assemblages in various and variable aquatic ecosystems is of paramount importance, given the strategic supporting services offered by these organisms. Such knowledge is implicitly based on the analysis of the realized niche of the different populations, i.e. of the sets of conditions within which populations show a positive growth. The range of phytoplankton morphological traits variability is evolutionarily selected to maximize the ecological performance of species while they are entrained in the spectrum of turbulent flows. In addition, most phytoplankton species exhibit high morphological plasticity that can further optimize their performance under reduced environmental variability. Although this plasticity is well known, it is seldom considered in phytoplankton studies. Morphological analysis could therefore be used as a tool to estimate the environmental variability within which a species can persist and, ultimately, the niche width of phytoplankton populations. This opinion paper tries to answer the questions: to what extent can the morphological variability of phytoplankton offer a synthesis of the environmental variability of aquatic ecosystems?. Do the morphological traits contain sufficient information to describe the width of the realized niche of phytoplankton species? What can we do to fill eventual gaps in our knowledge? [ABSTRACT FROM AUTHOR]

Eutrophication of water bodies causes the disappearance of submerged macrophytes and frequent blooms of phytoplankton, which leads to changes in the underwater light environment in the aspect of light intensity and light quality. However, compared with underwater light intensity, only few studies have been concentrated in the effect of light quality on submerged macrophytes. The effect of light quality on plants is heterogeneous, and there are two absorption peaks in red and blue wavelengths. Thus, we carried out a mesocosm experiment to study the effects of a series of red and blue light ratios (red/blue light ratio = 1/8, 1/4, 1/1, 4/1, and 8/1) on two submerged macrophyte species, Hydrilla verticillata and Vallisneria natans. We hypothesized that functional traits (growth strategy, morphological, photosynthetic, and nutritional traits) of submerged macrophytes will be modified by different red/blue light ratios. With the increase of red/blue light ratio, plant height of the two submerged macrophytes decreased, while tillers number increased. We could not completely verify our hypothesis, but we found species-specific differences. The leaf area of H. verticillata under 8/1 red/blue light ratio was significantly higher than that under 1/8 red/blue light ratio, whereas the leaf area of V. natans under 4/1 red/blue light ratio was lower than that under 1/8 red/blue light ratio. Our results are helpful to understand the disappearance mechanism of submerged macrophytes in eutrophic lakes and devise more appropriate measures for the recovery of submerged macrophytes. [ABSTRACT FROM AUTHOR]

Even in a biodiversity hotspot such as the Mediterranean basin, aspects relating to the distribution of some groups of microcrustaceans still need clarification. In this paper, we critically analyse the available information on diaptomid copepods in Tunisian inland waters and, based on the largest sampling campaign to date carried out in the country, report new data on their distribution. In the frame of this study, 248 crustacean samples were collected from 190 sites, and 10 diaptomid species belonging to 7 genera and 2 subfamilies were found in the samples. Their distribution follows a climate gradient determined by precipitation, and ecological variables mainly affect diaptomid distribution in the study area, while pure spatial factors are of negligible importance. Diaptomid biodiversity is therefore strongly linked to the diversity of inland waters that characterise the country. This is especially true in the wetlands of the Medjerda alluvial plain, where six diaptomid species co-occurred sympatrically, with up to four or five species coexisting syntopically and synchronically in some sites. Unfortunately, the natural water bodies of this plain are currently strongly threatened by urban expansion and agricultural reclamation, and the risk of local extinction for the species they host is increasingly high. [ABSTRACT FROM AUTHOR]

Both natural and anthropogenic processes can lead to the increasing salinity of surface waters. The knowledge about the ecological consequences of salinization on the biota is limited especially in case of microbiota, like diatoms. We collected the existing knowledge about the relationship between salinity and diatoms in fresh and saline waters. Based on the available papers, conductivity and ion composition are the most important variables shaping diatom communities. Secondary salinization can mask regional differences in diatom assemblages. Trait-based analyses highlight the competitive advantages of motile guild and the extreme trait categories in these environments. The increasing conductivity along a wide conductivity scale decreases the alpha-diversity. Salinization induces the spread and invasion of marine and brackish species into inland freshwaters as well as that of freshwater species tolerating elevated conductivity and/or need specific ions. Concerning food webs, salinity can directly change diatom communities and the subsequent upper trophic levels but most likely this effect manifests as a top-down regulation. Applicable diatom indices are available to assess the level of salinization. Furthermore, diatom-inferred salinity reconstructions are widely applied to assess the past changes of salinity. However, future models predicting ecological consequences of salinization are scarce and sometimes contradictory. [ABSTRACT FROM AUTHOR]

Understanding and connecting the impact of anthropogenic activities on mangrove food webs is a research challenge. Has research on the subject been able to find answers using stable isotopes? The present opinion paper analyzed the utility of stable isotopes in tracing the impact of anthropogenic activities on mangrove food webs and if the research questions raised could be answered using these chemical markers. Representative research papers (16) focused on the use of stable isotopes (δ13C, δ15N, δ34S, δ2H, δD,206Pb/207Pb, and 208Pb/207Pb) to evaluate the effect of anthropogenic activities (Sewage discharge, timber harvesting–deforestation, metallurgical activities, hydrological disruption, aquaculture ponds, and urban development) on mangrove food webs were selected. Each article included at least one group of consumers (invertebrate or fish). Publications only focused on water quality or primary producers were not included. Most studies managed to determine the effect of the anthropogenic activities on the food web's stable isotope values. Based on the above, we concluded that these markers are an effective tool to determine affectation patterns on the structure and function of mangrove food webs. The results obtained herein facilitate the correct management of mangroves and their derived resources. [ABSTRACT FROM AUTHOR]

Guest editors: Verónica Ferreira, Luis Mauricio Bini, Katya E. Kovalenko, Andre A. Padial, Judit Padisák & María de los Ángeles González Sagrario / Aquatic Ecosystem Services Introduction to ecosystem services Millennium Ecosystem Assessment The dependency of human wellbeing from ecological systems has been long recognized. The ecosystem services approach has provided background and motivated international legislation and agreements aiming to halt and reverse ecosystem degradation and biodiversity loss, such as the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), the UN Decade on Ecosystem Restoration, and the EU Nature Restoration Law. The papers included in this Special Issue, together with reviews on ecosystem services provided by other aquatic ecosystems and organisms (e.g., Barbier et al., [2]; Macadam & Stockan, [25]; Hilt et al., [14]; Riis et al., [37]; Janssen et al., [16]), contribute to highlighting the relevance of these ecosystems and organisms to human wellbeing, and emphasizing the need for their conservation and restoration. This is followed by 6 reviews addressing ecosystem services provided by specific aquatic ecosystems and 12 reviews addressing ecosystem services provided by different groups of aquatic organisms (Table 2). [Extracted from the article]

Bioassessment to evaluate stream integrity and determine changes related to point-source discharges is typically focused in wadeable streams, with limited understanding of seasonal and annual variation. We used a multi-year (n = 13), multi-site (n = 5–7), seasonally (spring and fall) sampled dataset to evaluate spatial and temporal patterns in diatom assemblages relative to measured environmental variables, land use, and pulp and paper mill discharges in a wadeable stream (Codorus Creek, PA) and three non-wadeable rivers (Leaf River, MS; McKenzie and Willamette rivers, OR). Analysis of variance (ANOVA) and permutational ANOVA (PERMANOVA) showed that significant spatial differences in commonly used diatom biotic integrity/diagnostic metrics and assemblage structure were common in the wadeable stream, but rare in the non-wadeable rivers. Season-specific diatom patterns were observed in all streams regardless of size, but annual variation was more prevalent in the non-wadeable rivers. Environmental variables explained 35–58% of the variability in diatoms in the spring and 33–50% in the fall, with physical habitat characteristics associated with stream morphology and seasonality more important than those associated with anthropogenic inputs such as land use and point sources. Findings from this study highlight the value of spatially and temporally comprehensive datasets in understanding and interpreting diatom assemblage patterns. [ABSTRACT FROM AUTHOR]

We carried out a literature review to investigate the taxonomic and functional β diversity of zooplankton and its species replacement (βrepl) and richness difference (βrich) components in Brazilian rivers. In addition, the taxonomic (LCBD-t) and functional ecological uniqueness (LCBD-f) were also measured. We tested the following hypotheses: (i) The βrepl component is the main driver of taxonomic β diversity, while βrich is most important for functional β diversity, due to functional simplification; (ii) Sites with lower taxonomic and functional richness are the ones that most contribute to LCBD. Contrary to expectations, βrich drove the taxonomic and functional β diversity. This may have occurred due to environmental constraints and geographic distance, thus causing a loss or gain of species and traits between hydrographic regions. For just two regions, the sites with the lowest functional richness were the ones that most contributed to LCBD-f. This reinforces that sites with lower richness can support species that perform unique functions in the ecosystem. As studies involving zooplankton from lotic systems are still limited in Brazil, we suggest that future research should consider the patterns of β diversity in these dynamic, diverse, and threatened aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The application of modern molecular methods and phylogenetic approaches saw an explosion in cyanobacterial taxonomy in the first two decades of the twenty-first century. The relative ease of description of new taxa and the pressure to publish a high number of scientific papers has created apparent confusion. The situation is particularly complicated for ecologically oriented limnological research and practical hydrobiologists especially have numerous criticisms of this trend. On closer observation, however, the situation is not as tragic as it first appears. More than a thousand new species have been discovered or renamed and only 18 percent are freshwater planktonic species, which garner the most interest in routine analyses. Most new taxa are described from terrestrial habitats. Despite the increase in studies from tropical areas, most of the new species are from the temperate zone, which probably does not account for the reality. Significant advances in modern taxonomy are visible mainly for the trichal types, but other groups such as the pleurocapsal species are considerably less studied. In this article I try to show that, despite all the difficulties and limitations, it is not necessary to consider these rapid changes as a complication in common cyanobacteriological research. [ABSTRACT FROM AUTHOR]

During the process of seabed mining, sediment redeposition will lead to the burial of organisms in the seabed environment, resulting in the death of benthos. The study of the effect of burial on megabenthos is an important part of environmental impact assessment before seabed mining. However, the molecular mechanism of the reaction of marine megabenthos to burial is still unclear. In this paper, a transcriptomic study of response to sediment burial is carried out for the widely distributed marine brittle star Ophiothrix exigua. Differentially expressed genes were identified through transcriptome sequencing. The most enriched GO terms included acting on L-amino acid peptides, peptidase activity, transport vesicle, phagocytic vesicle, zymogen granule membrane, basement membrane, vesicle lumen, secretory granule and induction of programmed cell death. The results of the KEGG pathway enrichment analysis of DEGs showed that sediment burial will cause different levels of impacts on brittle stars, including changes in signal pathways, metabolic regulation, and the immune system. The findings will enhance our understanding of the effect of burial on megabenthos in the sea. [ABSTRACT FROM AUTHOR]

Monitoring the condition (water quality, biodiversity, hydromorphology) of small water bodies presents a challenge for the relevant authorities in terms of time and resources (labour and financial) due to the extensive length of the stream network or the sheer number of small standing water bodies. Citizen science can help address information gaps, but the effort required should not be underestimated if such projects are to generate reliable and sustained data collection. The overall aim of this paper is to propose a framework for operationalisation of citizen science targeting collection of data from small water bodies. We first consider the data gaps and the elements (water chemistry, ecology, hydromorphology) to be addressed, in order to define where citizen science could best make an impact. We review examples of tools and methods that are appropriate for small water bodies, based on experience from a selection of freshwater citizen science projects, and the support that is needed for effective and sustained small water body projects across Europe. [ABSTRACT FROM AUTHOR]

Phytoplankton, the ecological group of microalgae adapted to live in apparent suspension in water masses, is much more than an ecosystem's engineer. In this opinion paper, we use our experience as phytoplankton ecologists to list and highlight the services provided by phytoplankton, trying to demonstrate how their activity is fundamental to regulate and sustain Life on our Planet. Although the number of services produced by phytoplankton can be considered less numerous than that produced by other photosynthetic organisms, the ubiquity of this group of organisms, and their thriving across oceanic ecosystems make it one of the biological engines moving our biosphere. Supporting services provided by phytoplankton include almost half of the global primary and oxygen production. In addition, phytoplankton greatly pushes biogeochemical cycles and nutrient (re)cycling, not only in aquatic ecosystems but also in terrestrial ones. In addition, it significantly contributes to climate regulation (regulating services), supplies food, fuels, active ingredients and drugs, and genetic resources (provisioning services), has inspired artistic and craft works, mythology, and, of course, science (cultural services), and much more. Therefore, phytoplankton should be considered in all respects a true biosphere's engineer. [ABSTRACT FROM AUTHOR]

River-floodplain ecosystems (RFEs) provide multiple ecosystem services. However, their importance may be underestimated because they are not summarized yet. In this paper, we review and update the benefits that RFEs provide to society, including supporting, regulating, provisioning, and cultural ecosystem services. Although considered a unique ecosystem service category, we advocate that supporting services, like soil formation, nutrient cycling, primary production, and habitat provisioning can be comprehended as ecosystem processes that generate other services. RFEs provide valuable regulating services, including water regulation, storm protection, erosion control, water purification, waste treatment, and disease control. The society also benefits from provisioning services from RFEs, such as water for drinking and irrigation, food (e.g., fishes and crops), fiber, ornamental and biochemical resources, and energy production. RFEs also provide cultural services including recreation, ecotourism, religiosity, and spirituality. Most ecosystem services from pristine and human-altered RFEs are primarily regulated by the flood pulse because it maintains temporal and spatial habitat variability, high biodiversity, and biotic and abiotic interactions. Despite providing many benefits to society, RFEs are seriously threatened, mainly due to river regulation, land-use changes, pollution and invasive species. Consequently, the multiple demands and uses of RFEs worldwide raise challenges of conservation and restoration. [ABSTRACT FROM AUTHOR]

The present paper is a review of the available literature on the significance of forage fish, the plethora of services they provide, and the threats faced by them. Forage fish are pelagic planktivorous species that operate as conduits of energy between the lower trophic level (plankton) and the upper trophic level (predators). A variety of ecosystem services are provided by them, from serving as prey for higher trophic levels to producing fish meal and oil. Forage fish have a consumption value for humans and cultural importance to many societies. Forage fish have faced constant natural and anthropogenic threats in the past, resulting in numerous fish collapses which subsequently impacted their predators. The economic benefit provided by forage fish has been estimated to be approximately $ 18.7 billion per annum. An introspection of the data on ecosystem services revealed lack of data on regulating and cultural services, eventually leading to a monetary underestimation and their commercial prioritization over the wider benefits they provide. [ABSTRACT FROM AUTHOR]

The ecosystem services approach to conservation is becoming central to environmental policy decision making. While many negative biological invasion-driven impacts on ecosystem structure and functioning have been identified, much less was done to evaluate their ecosystem services. In this paper, we focus on the often-overlooked ecosystem services provided by three notable exotic ecosystem engineering bivalves, the zebra mussel, the quagga mussel, and the golden mussel. One of the most significant benefits of invasive bivalves is water filtration, which results in water purification and changes rates of nutrient cycling, thus mitigating the effects of eutrophication. Mussels are widely used as sentinel organisms for the assessment and biomonitoring of contaminants and pathogens and are consumed by many fishes and birds. Benefits of invasive bivalves are particularly relevant in human-modified ecosystems. We summarize the multiple ecosystem services provided by invasive bivalves and recommend including the economically quantifiable services in the assessments of their economic impacts. We also highlight important ecosystem disservices by exotic bivalves, identify data limitations, and future research directions. This assessment should not be interpreted as a rejection of the fact that invasive mussels have negative impacts, but as an attempt to provide additional information for scientists, managers, and policymakers. [ABSTRACT FROM AUTHOR]

Short-term zooplankton grazing experiments in bottles were conducted with water from 12 Danish brackish lakes covering a large gradient in salinity (0.3-17.4 ppt) as well as from mesocosms conducted in the same area with various salinities (0.5-12 ppt), two nutrient levels and low fish density (14). However, the ongoing climate change along with the already experienced extremes and a number of anthropogenic activities have increased their salinity at places and/or increased the amplitude of the salinity changes (Lengyel et al., [13]; B-Béres et al., [1]; Cortez et al., [5]). Also, in lentic environments of a drying coastal plain of Southeast Brazil, a comparison between stenohaline (i.e. narrow salinity tolerance ranges) and euryhaline (i.e. wide salinity tolerance ranges) fish species showed non-random patterns of community composition. Incubation under a range of salinities (5-57 ppt) indicated lower photosynthetic performance at increased salinity for both species, which increased their organic osmolyte contents with rising salinity stress. [Extracted from the article]

Rotifer structure may serve as predictor of environmental features, including temperate subclimates between water bodies. The difference in latitude between two temperate regions (Poland vs. Croatia) affects the identification of particular environmental factors that subsequently influence the taxon-related indices of rotifers. A study on 10 water bodies found that taxon-trait indices were sensitive in identifying latitude differences, even though extreme weather conditions were not considered, and only two seasons (spring and autumn) were examined. A variable rotifer community, with a high share of rare species, was obtained. We found a distinctiveness of abiotic factors between both countries, indicating a higher trophic state in Poland. Although habitat conditions were more similar in spring compared to the autumn, the percentage of rotifer common taxa was alike in both seasons but variation in distinct species community was clear. Trophic state increase in Poland was reflected in the structure of dominant and distinct species, with a wide range of eutrophy indicators. Comparing how rotifer species respond to environmental conditions is important for developing methods to assess trophic state changes due to climate change. Single species, distinct or rare species, are often the first sign of changes. [ABSTRACT FROM AUTHOR]

Exceptional resistance to dehydration allows species of bdelloid rotifers to tolerate desiccation stress in unpredictable habitats. The roles of exogenous and endogenous factors in resistance to short-term dehydration were investigated in Rotaria rotatoria to better understand this capacity among bdelloid rotifers. As the dehydration period was increased and the relative humidity (RH) was reduced, the proportion of rotifers active after the dehydration period decreased. The RH and dehydration period substantially influenced the recovery rate of R. rotatoria under rehydration for 1 h but had less effect under 12-h or 24-h rehydration treatment. The recovery rate was lower in rotifers subjected to a long dehydration period and short rehydration time, but improved by shortening the dehydration period and extending the rehydration treatment. Strain ZJ27 showed higher survivability than strain HX8, appropriate to their habitat near the sea in a region where drought and tropical rainstorms are frequent. Accordingly, species or strains originating from different climate regions and habitats will have experienced different frequencies of desiccation over their adaptive evolutionary history, resulting in varying levels of resistance among species. In addition, RH is shown to be a key factor in resistance to desiccation. [ABSTRACT FROM AUTHOR]

Zooplankton indicators based on rotifers (TSIROT) and an indicator based on Secchi disk visibility (TSISD) were used to assess trophic state changes in artificial, slow-flowing, and stagnant canal waters. The study was conducted in the summers of 2019, 2021, and 2022 in the Bydgoszcz Canal and the Noteć Canal (Poland). Water samples were taken from five sites once in the month of July and once in August. In terms of the species number and density, rotifers dominated among zooplankton (at almost all sites), which reflected the high trophic state. Our results showed statistically significant correlations between TSIROT and TSISD as well as between the individual indicators TSIROT1 (Rotifer numbers), TSIROT2 (Rotifer biomass), TSIROT3 (bacterivorous numbers of rotifers), TSIROT6 (rotifers indicating high trophic state), and TSISD. According to our study, the presented indices most likely determine the trends between TSIROT cumulative and TSISD in the studied canals. Similarly to previous studies performed on lakes and small reservoirs, zooplankton constituted a useful indicator of trophic state. It seems that, for stagnant and slowly flowing waters of canals such as the Bydgoszcz Canal and the Noteć Canal, the method of zooplankton trophic status indicators based on rotifers may be applied. [ABSTRACT FROM AUTHOR]

Most species of Keratella possess dome-shaped, dorsal plates comprising a network of polyhedral units (facets), delineated by slightly raised ridges. The arrangement of facets define a species' facet pattern (FP), with the resulting structure resembling a geodesic dome. Researchers have sorted species into categories based on their FPs, but those have not been analyzed. Additionally, while a strong lorica has been suggested to protect Keratella from predatory attack or other actions causing blunt force trauma (BFT), we know little of how that occurs. Thus, in our study we tested two hypotheses. (1) There is support for categorizing Keratella species into unique groupings based on their FPs. (2) FPs provide resistance to physical stresses. To test that hypothesis we used the structural analysis software SkyCiv©. Our results indicate support for four FP categories. Additionally, the SkyCiv analysis provided preliminary 'proof-of-concept' that Keratella FPs have a functional significance: i.e., adding or subtracting facets in our model was followed by a change in predicted structural reliability. We posit that FPs are adaptations protecting Keratella from fractures to the lorica that may result from BFT incurred during predatory attack by copepods or while caught within the branchial chambers of daphnids. [ABSTRACT FROM AUTHOR]

The invasive red swamp crayfish Procambarus clarkii (Girard, 1852) can affect freshwater ecosystems, their macrophyte communities in various ways. To examine the effects of red swamp crayfish on clearwater macrophyte-dominated lakes, we performed a 28-day mesocosm experiment, without and with presence of red swamp crayfish, with or without access to sediments using netting. All in the presence of one of the following three different submerged macrophytes: Myriophyllum spicatum L., Vallisneria denseserrulata (Makino) Makino, or Hydrilla verticillate (L.f.) Royle. This experimental design allowed a partial separation of the effects of disturbing the sediment using netting from other factors such as excretion and direct harm of the plants. Nutrients and total suspended solids concentrations were lower in the crayfish-with-net than in the crayfish-without-net treatments but had similar concentrations in the crayfish-with-net and crayfishless-without-net treatments. Compared to the crayfish-with-net treatment, there were more broken leaves in the crayfish-without-net treatments for V. denseserrulata and H. verticillata, while no difference was found for M. spicatum, likely reflecting their different growth forms. Our results suggest that the sediment disturbance by the crayfish was more important than their plant handling/consumption and nutrient excretion for an observed water quality change from clear to turbid. [ABSTRACT FROM AUTHOR]

When restoring shallow lakes, the recovery of submerged macrophytes is of vital importance to obtain clear water conditions. However, post-restoration recovery of small omnivorous fish can increase water nutrient concentrations through excretion. The impact of these recycled nutrients on submerged macrophytes is not well-studied, and it may depend on fish food of varying nutrient contents. We studied the effects of Acheilognathus macropterus on the growth and nutrient stoichiometry of Vallisneria denseserrulata and Hydrilla verticillata. The experiment had six treatments: two controls without recycled nutrients and two nutrient treatments for each of the plant species, respectively. We found that fish released more phosphorus after consuming low N:P food and more nitrogen after high N:P food. The recycled nutrients significantly promoted the growth of both macrophyte species. Interestingly, macrophytes showed higher growth rates in treatments with nutrients from the low N:P food source. Our study, therefore, suggests that nutrient subsidy from fish excretion can significantly stimulate the growth of submerged macrophytes, the magnitude of the effect being determined by the N:P ratio of the fish food. The realization of this growth potential, however, also depends on the phytoplankton response to these nutrients, that expectedly will be weaker at high macrophyte coverage. [ABSTRACT FROM AUTHOR]

Cyanobacterial blooms have a strong impact on the food web structure, interactions and ecosystem functioning. The aim of this study was to describe the seasonal changes in composition and abundance of heterotrophic nanoflagellates, ciliates, rotifers, and crustaceans in relation to algae and nutrients in a shallow eutrophic lake (north-eastern Poland) dominated by cyanobacteria and exposed to the strong impact of cormorants. Our results showed that algae accounted for a small part of the total phytoplankton abundance (9–40%) and biomass (10–21%) and were dominated by diatoms and cryptophytes. All of the studied groups of planktonic organisms were quite rich in species (95 algal, 79 ciliate, 44 rotifer and 25 crustacean species) and relatively abundant. Copepods formed a substantial part (45–83%) of the total zooplankton biomass during all seasons. Relatively low algal to zooplankton biomass ratio (0.8–1.1) suggests that during spring, summer, and winter algae were not sufficient food resources for metazooplankton, which supplemented its diet with protists (heterotrophic nanoflagellates and ciliates). In a shallow lake dominated by cyanobacteria, winter (ice-covered period) may be a more favourable period for the growth of some groups of algae, ciliates and rotifers than other seasons due to decreasing abundance of cyanobacteria. [ABSTRACT FROM AUTHOR]

Mangroves stand as unique blue-carbon ecosystems in intertidal tropical and subtropical coastal regions, renowned for their significant contributions to vital ecosystem services like coastal provisions and protection. Mangrove coverage in Malaysia ranks sixth globally, representing nearly 5% of the entire worldwide mangrove ecosystem. Despite the crucial role that mangroves play in Malaysia's ecosystem, a comprehensive review of their status, structures, functions, services, and restoration efforts, as well as their vulnerability to changing climates, has been lacking. Our review indicated that sediment carbon stocks in Malaysian mangrove forests span from 0.8 to 352 megagrams of carbon per hectare (hereafter referred to as Mg C ha−1). There has been an increasing research interest in ecosystem services, especially those related to mangrove ecotourism. Natural factors, coastal reclamations, and coastal pollution are considered to be the primary drivers of mangrove ecosystem degradation in Malaysia. Substantial restoration initiatives have been implemented in the country, involving assisted biotic restoration and the transplantation of mangrove seedlings into the restored sites. Mangroves confront impending climate change challenges, which encompass rising sea levels, increasing storms, climate warming, and coastal erosion. This study carries implications for the functioning of coastal ecosystems and provides valuable insights for coastal resource managers. [ABSTRACT FROM AUTHOR]

The long-term dynamics of production of the glacial relict amphipod Monoporeia affinis was examined in a small subarctic lake. The aims of this study were: (1) to compare the production of amphipods with their biomass; (2) to relate the changes in amphipod population with environmental variables. I hypothesized secondary production could provide better insight into M. affinis population dynamics, than abundance and biomass alone. Production (increment-summation method) and its standard error were estimated based on benthic samples taken at a sublittoral site from June 2002 to May 2019 (as a rule, 4–5 times a year). Production and biomass were highly correlated with each other. The annual P/B ratio varied twofold. However, the majority of estimates did not differ significantly from the mean P/B value for the study period. Effects of environmental variables (water temperature and chlorophyll-a concentration) were pronounced for offspring and juvenile amphipods only. The older amphipods showed no significant correlation with any environmental variables. Despite the initial prediction, no reliable evidence was found that production revealed greater insight into population dynamics of M. affinis. This long-term study confirms that benthic production is mainly a function of biomass. [ABSTRACT FROM AUTHOR]

Marine habitat-forming species create structurally complex habitats that host macroinvertebrate communities characterized by remarkable abundance and species richness. These habitat-forming species also play a fundamental role in creating favourable environmental conditions that promote biodiversity. The deployment of artificial structures is becoming a common practice to help offset habitat loss although with mixed results. This study investigated the suitability of artificial flexible turfs mimicking the articulated coralline algae (mimics) as habitat providers and the effect of ocean acidification (OA) on early stage ecological communities associated to flexible mimics and with the mature community associated to Ellisolandia elongata natural turfs. The mimics proved to be a suitable habitat for early stage communities. During the OA mesocosms experiment, the two substrates have been treated and analysed separately due to the difference between the two communities. For early stage ecological communities associated with the mimics, the lack of a biologically active substrate does not exacerbate the effect of OA. In fact, no significant differences were found between treatments in crustaceans, molluscs and polychaetes diversity and abundance associated with the mimics. In mature communities associated with natural turfs, buffering capability of E. elongata is supporting different taxonomic groups, except for molluscs, greatly susceptible to OA. [ABSTRACT FROM AUTHOR]

Increasing nutrient inputs driven by global environmental pressures may lead to changes in prokaryotic plankton biomass and community composition in coastal environments. Nutrient addition experiments (inorganic, organic, and mixed) were performed at the continental shelf outside the Ría de Vigo, in spring, summer and autumn 2014, and the results contrasted with those from similar previous experiments carried out inside the ría in 2013. The mixed nutrient additions caused the greatest changes in community composition, mostly consisting of blooms of Vibrionales. Inorganic nutrients yielded increased proportions of Oceanospirillales and Alteromonadales. Euclidean distances among samples were used to estimate compositional resistance to disturbances derived from nutrient additions. Changes in prokaryotic biomass were used as an indicator of biomass resistance. Generally, prokaryotic communities were more resistant to inorganic than organic nutrient additions. Communities sampled inside the ría, presumably exposed to greater perturbations, showed milder variability in the non-amended control than those from outside the ría. By contrast, shelf communities, with higher ambient organic matter concentrations, were more resistant to organic and mixed nutrient additions than those from the ría. Our data suggest that the perturbation history is related to the resistance of microbial communities to changes in nutrient inputs into the coastal ocean. [ABSTRACT FROM AUTHOR]

Online searches for relevant scientific references using keywords have become common practice. Several multidisciplinary scientific online databases are available, of which Web of Science, Scopus (both payable) and Google Scholar (free of charge) are the most commonly used. We test the hypothesis that results of highly similar searches in these three databases do not necessarily give comparable results. We set out to query the three databases with a real example on "diapause in microcrustaceans" (Cladocera, Copepoda and Ostracoda), using the same time period (2012–2021), the same keywords with the same syntaxis and the same sorting criterion ("relevance"), and compared the first 100 hits provided by each database. There were several references provided which were irrelevant to the search, especially in the Web of Science, and of the remaining relevant references, only 9.84% were provided by all three databases. Our survey showed significant differences amongst the results provided by the databases, especially for "hydroperiod" and "type of environment". These differences can be the result of different coverage of the scientific literature by the databases, but also of the different ways by which the criterion "relevance" is calculated by the three algorithms. We, therefore, recommend that literature surveys must be based on several databases; otherwise, the results might become biased. [ABSTRACT FROM AUTHOR]

The analysis of ecological niche is an important task to correctly identify the role exerted by species within ecosystems, to assess their vulnerability, to plan effective measures addressed at fulfilling the postulates of biological conservation, and ultimately to prevent biodiversity loss. However, for the majority of organisms our knowledge about the actual extent of their ecological niche is quite limited. This is especially true for microscopic organisms. Evidence exists that in different geographical areas allegedly conspecific populations can show different, if not antithetical, ecological requirements and not-overlapping ecological niches. This opinion paper discusses whether this "niche displacement" effectively occurs between conspecific populations or if the pattern is rather due to an inaccurate identification of species and/or to an insufficient knowledge about population and community ecology. Hence, some subjectively selected study cases when alleged phenomena of niche displacements take place are presented, and shortfalls in the correct assessment of the identity and ecological niches of microscopic aquatic eukaryotes, namely phytoplankton, zooplankton, and meiofauna are shown. [ABSTRACT FROM AUTHOR]

The impacts of biological invasions remain poorly known for some habitats, regions and taxa. To date, there has been no comprehensive effort to review and synthesize the impacts of invasive mollusc species in South America. In this paper, we provide a synoptic view on what is known on documented socio-ecological impacts of aquatic no-native mollusc species (NNMS) and transplanted mollusc species (TMS) from South America. An expert group involving malacologists and taxonomists from different countries, the "South America Alien Molluscs Specialists" (eMIAS), shared and summarized the scientific literature, databases, and published and unpublished information on confirmed impacts of NNMS and TMS in South America. Three broad categories, non-mutually exclusive were used as a framework: "Environmental/Biodiversity impacts", "Economic and social effects", and "Human health impacts". Some 21 NNMS and seven TMS have documented impacts on at least one of those three categories. We encourage targeting the less known areas of research, such as economic valuation of human health (and veterinary) impacts attributable to NNMS or TMS and expand our knowledge of environmental impacts for the species listed in this study. [ABSTRACT FROM AUTHOR]

The text is a preface to a special issue of the journal Hydrobiologia, titled "Trait-Based Approaches in Micro-Algal Ecology." The preface provides an overview of the 19th workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP), which focused on trait-based approaches in micro-algal ecology. The workshop brought together scientists and students from various countries to discuss ecological topics and practice species identification. The preface also mentions the history of the IAP workshops and the special issue's dedication to Colin S. Reynolds, a prominent phytoplankton ecologist. The special issue includes a selection of review and research papers covering a wide range of spatial and temporal scales and aquatic habitats. The authors express gratitude to the referees, editorial staff, and workshop participants. [Extracted from the article]

Research on climate change, water quality, and their relationship is critical for human survival and development. It can help better mitigate climate change and contribute to appropriate water quality management strategies under uncertain challenges in the future. In this study, bibliometric analysis was used to provide a comprehensive review of the research field of climate change and water quality from 1990 to 2022. The extraction of documents was carried out from the Web of Science Core Collection database. VOSviewer, Bibliometrix R-package, and CiteSpace were used for analysis and scientific mapping. The results show that China, the United States, and Canada are the main countries driving this field, and China and the United States closely cooperate. It was also found that the areas of water eutrophication and climate change research had a close relationship and were the current research hotspots. Finally, it is revealed that the areas of sustainable development of climate change and water quality management, model simulation and method improvement between climate change and water quality, groundwater quality risk assessment driven by climate change, the impact of water on climate change, and expanding the research scale of the relationship between climate change and water quality will be the future research trends in this field. [ABSTRACT FROM AUTHOR]

This paper offers a brief overview of the contributions provided by widely recognised phytoplankton ecologists to honour the memory of an undisputed leader in the field of aquatic sciences: Colin S. Reynolds. Colin passed away quite unexpectedly in December 2018 causing a wave of sorrow that rapidly circulated among friends and colleagues all over the world. The 14 review papers collected in this Special Issue form a tribute to Colin's scientific thinking, which survives the man and represents a legacy to all the scientists in the field, especially to young generations. Although authors and editors carefully selected 14 different topics, a certain degree of overlap exists among the collected contributions. This, far from being a limit, further underlines the holistic nature of Colin's vision about phytoplankton and shows the need to develop a comprehensive cultural framework when analysing this complex ecological group of organisms. [ABSTRACT FROM AUTHOR]

Text-analysis tools focused on limnology research allowed us to find three approaches in the analysis of ecosystems services (ES) provided by bacteria, archaea and viruses: (i) a prevalence of taxonomic analyses focused on the relevance of microbial biodiversity in sustaining ES, (ii) studies focused on diversity and functional aspects of bacteria, archaea and viruses and their ES provided and (iii) research focused on disservices. Supporting, regulating and provisioning services were the most discussed. Significant gaps include knowledge about the ecological traits of prokaryotic taxa and viral particles, quantitative information on microbial community-level functions integrated through different ecosystems, and a deeper integration of positive and negative microbial community functional attributes and their feedbacks to ecosystem services provision. Future research should include: (i) development of new bioinformatic tools coupled to theoretical and methodological frameworks leading to a more powerful analysis of metagenomic data, (ii) inclusion of earth observation data for comprehensive modeling of large-scale assessment of ES and its valuation, (iii) advance investigation on the ecological processes that viruses support in the environment and its significance for the ecological performance of microbial communities' services provision. [ABSTRACT FROM AUTHOR]

We respond to comments made in the opinion paper by Ainley et al. (Hydrobiologia, 10.1007/s10750-015-2607-4, ) regarding our recent publication on the biology, ecology and life history of Antarctic toothfish ( Dissostichus mawsoni) in the Ross Sea region. We focus in particular on the spatial and temporal extent of data collected from the fishery; results of research to date on changes in abundance and size of Antarctic toothfish at McMurdo Sound; and the subject of neutral buoyancy and inferences about vertical distribution. We conclude by re-iterating the need for well-designed, standardised research programmes to address remaining uncertainties in its life history. [ABSTRACT FROM AUTHOR]

Urban ecology is a promising research field in limnology, but we still need to evaluate how urban waterbodies can sustain biodiversity. In this paper, we present a comprehensive foodweb perspective of urban waterbodies in the city of Montréal (Québec, Canada). The research goals are to evaluate if biodiversity and community structure of foodweb components (phytoplankton, zooplankton, and macroinvertebrates) are valuable tools for assessing the ecological status of urban waterbodies and examine how they are controlled by multiple factors related to trophic status and habitat complexity (origin, water residence, macrophyte cover, fish, and management practices). Multiple factor analysis, correlations, and non-parametric tests were used to examine the relationships between the environmental factors and foodweb biological variables. Our case study confirms that urban waterbodies are important sources of biodiversity and reveals that foodweb-based biological indicators are reliable tools for the biomonitoring of urban waterbodies. Foodweb biodiversity and community structure were more influenced by habitat complexity than by trophic status. The key determinants of variation were the differences in water regime, management of temporary and permanent waterbodies, and contrasts in habitat complexity depending on pond origin (artificial or natural) and macrophyte cover. [ABSTRACT FROM AUTHOR]

Seedlings of two species of mangroves, Bruguiera gymnorrhiza and Rhizophora apiculata, were monitored for 8 years on the Pacific island of Kosrae, Federated States of Micronesia, to determine the effects of canopy cover and hydrogeomorphic zone on long-term survival and growth. Annual rainfall is high with little seasonality. Study plots with seedling subplots were in fringe, riverine, and interior hydrogeomorphic zones along four small rivers. The height of each seedling was measured each year and was designated each time as being under an open, partially closed, or closed canopy. Growth rates of both species were slow, and no seedling that was newly established during the study became a sapling (2 m). Many seedlings stopped growing for long periods of time. Bruguiera seedlings were more numerous than Rhizophora seedlings. They grew faster than Rhizophora seedlings except in riverine zones. Predicted growth rates of Bruguiera were fastest under an open canopy and slowest under a closed canopy, but Rhizophora was not affected by canopy status. Overall mortality rates for the two species were similar, averaging 36% year−1. El-Niño-Southern Oscillation events did not affect growth or mortality but may have caused some defoliation. [ABSTRACT FROM AUTHOR]

As a result of a field trip in 1980 to the monsoonal wetland of the Keoladeo National Park, India, which was organized by Dr. Brij Gopal, a study of the vegetation dynamics of this wetland was initiated. The original hypothesis for this study was that the seasonal vegetation changes caused by the annual summer monsoon was a compressed habitat cycle. Habitat cycles are a characteristic of prairie potholes in North America. Habitat cycles are the result of wet–dry cycles that last from 5 to 25 years during which the vegetation of a pothole changes from dense emergent vegetation (dry years) to open water with only submerged vegetation (wet years). In retrospect, our field studies were not consistent with our hypothesis. The increase in water level caused by the monsoon was not large enough to kill the emergent vegetation, as happens during prolonged high-water years in prairie potholes. However, both wetland types have significant seed banks that allow their plant species to survive adverse conditions. We now believe that the vegetation dynamics of monsoonal wetlands are best described as seasonal shifts between a wet marsh phase when the wetland is flooded and a dry grassland phase when it is not. [ABSTRACT FROM AUTHOR]