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Assessments of ecosystem functioning are a fundamental ecological challenge and an essential foundation for ecosystem‐based management. Species trophic position (TP) is essential to characterize food web architecture. However, despite the intuitive nature of the concept, empirically estimating TP is a challenging task due to the complexity of trophic interaction networks. Various methods are proposed to assess TPs, including using different sources of organic matter at the base of the food web (the 'baseline'). However, it is often not clear which methodological approach and which baseline choices are the most reliable. Using an ecosystem‐wide assessment of a tropical reef (Marquesas Islands, with available data for 70 coral reef invertebrate and fish species), we tested whether different commonly used TP estimation methods yield similar results and, if not, whether it is possible to identify the most reliable method. We found significant differences in TP estimates of up to 1.7 TPs for the same species, depending on the method and the baseline used. When using bulk stable isotope data, the choice of the baseline significantly impacted TP values. Indeed, while nitrogen stable isotope (δ15N) values of macroalgae led to consistent TP estimates, those using phytoplankton generated unrealistically low TP estimates. The use of a conventional enrichment factor (i.e. 3.4‰) or a 'variable' enrichment factor (i.e. according to feeding guilds) also produced clear discrepancies between TP estimates. TPs obtained with δ15N values of source amino acids (compound‐specific isotope analysis) were close to those assessed with macroalgae. An opposite seasonal pattern was found, with significantly lower TPs in winter than in summer for most species, with particularly pronounced differences for lower TP species. We use the observed differences to discuss possible drivers of the diverging TP estimates and the potential ecological implications. Based on a case study from a remote coral reef ecosystem in the Pacific Ocean, this work analyses how several potential sources of organic matter (i.e. 'baselines') and calculation methods strongly affect assessments of trophic positions. We also demonstrated that seasonal temporality and feeding guild are important parameters to be considered. [ABSTRACT FROM AUTHOR]

Remote-sensing methods are being used to study a growing number of issues in the San Francisco Estuary, such as (1) detecting the optical properties of chlorophyll-a concentrations and dissolved organic matter to assess productivity and the nature of carbon inputs, (2) creating historical records of invasive aquatic vegetation expansion through space and time, (3) identifying origins and expansions of invasions, and (4) supporting models of greenhouse-gas sequestration by expanding restoration projects. Technological capabilities of remote sensing have likewise expanded to include a wide array of opportunities: from boat-mounted sensors, human-operated low-flying planes, and aerial drones, to freely accessible satellite imagery. Growing interest in coordinating these monitoring methods in the name of collaboration and cost-efficiency has led to the creation of diverse expert teams such as the Remote Imagery Collaborative, and monitoring frameworks such as the Interagency Ecological Program Aquatic Vegetation Monitoring Framework and Wetland Regional Monitoring Program. This paper explores the emerging technologies and applications of various methods for studying primary producers, with an emphasis on remote sensing.

Phytoplankton are photosynthetic microscopic organisms that inhabit the upper sunlit layer (euphotic zone) of marine and fresh water bodies. Phytoplankton, as the primary producer of the aquatic ecosystem’s food chain and are very sensitive to environmental changes as energy stored up in them determine the basic primary productivity of an ecosystem. There is dearth of information on the phytoplankton community of the Festac creek and thus the need for this study which aims at microscopically investigating the phytoplankton community of the Festac creek. The Phytoplankton diversity and distribution of the Festac creek, Lagos, Nigeria. was investigated for 12 months (November 2021 – October, 2022). Phytoplankton samples were collected monthly for 12 months, using a 55 μm mesh size standard plankton net towed horizontally from a motorized boat for 5 mins at < 4 Km/h and preserved by adding 4% unbuffered formalin. The drop count microscopic analysis method was used to study the phytoplankton species. A total of 34 phytoplankton species from 7 algal classes namely Bacillariophyceae (16 species), Cyanophyceae (9 species), Chlorophyceae (2 species), Conjugatophyceae (3 species), Dictyochophyceae (2 species), Tintinnid (1 species) and Dinophyceae (1 species) were recorded. Notable species were recorded such as: Lyngbya sp, Prorocentrum lima, Navicula sp. Nitzschia lineola, Phormidium bohneri, Oscillatoria limosa, Oscillatoria nigro viridis, Oscillatoria formosa and some other known marine species such as Coscinodiscus radiatus, Coscinodiscus marginatus Skeletonema costatum, Odontella sinensis, Thalassionema nizschoides, Fragillaria oceanica, Spirulina subsalsa and Tintinnopsis radix. The most abundant class was the Cyanophyceae (Blue-green algae) with Oscillatoria limosa being the most abundant species. This could be attributed to the constant addition of nutrient particularly nitrate and phosphate run offs from industries around the study area which enhances cyanobacterial growth and indicates that the Festac creek is eutrophic. [ABSTRACT FROM AUTHOR]

Abstract Assessments of ecosystem functioning are a fundamental ecological challenge and an essential foundation for ecosystem‐based management. Species trophic position (TP) is essential to characterize food web architecture. However, despite the intuitive nature of the concept, empirically estimating TP is a challenging task due to the complexity of trophic interaction networks. Various methods are proposed to assess TPs, including using different sources of organic matter at the base of the food web (the ‘baseline’). However, it is often not clear which methodological approach and which baseline choices are the most reliable. Using an ecosystem‐wide assessment of a tropical reef (Marquesas Islands, with available data for 70 coral reef invertebrate and fish species), we tested whether different commonly used TP estimation methods yield similar results and, if not, whether it is possible to identify the most reliable method. We found significant differences in TP estimates of up to 1.7 TPs for the same species, depending on the method and the baseline used. When using bulk stable isotope data, the choice of the baseline significantly impacted TP values. Indeed, while nitrogen stable isotope (δ15N) values of macroalgae led to consistent TP estimates, those using phytoplankton generated unrealistically low TP estimates. The use of a conventional enrichment factor (i.e. 3.4‰) or a ‘variable’ enrichment factor (i.e. according to feeding guilds) also produced clear discrepancies between TP estimates. TPs obtained with δ15N values of source amino acids (compound‐specific isotope analysis) were close to those assessed with macroalgae. An opposite seasonal pattern was found, with significantly lower TPs in winter than in summer for most species, with particularly pronounced differences for lower TP species. We use the observed differences to discuss possible drivers of the diverging TP estimates and the potential ecological implications.

Salinization and warming are of increasing concern for freshwater ecosystems. Interactive effects of stressors are often studied in bifactorial, two-level experimental setups. The shape of environmental reaction norms and the position of the “control” conditions along them, however, can influence the sign and magnitude of individual responses as well as interactive effects. We empirically model binary-stressor effects in the form of three-dimensional reaction norm surfaces. We monitored the growth of clonal cultures of six freshwater diatoms, Cymbella cf. incurvata, Nitzschia linearis, Cyclotella meneghiniana, Melosira varians, Ulnaria acus, and Navicula gregaria at various temperature (up to 28 °C) and salinity (until the growth ceased) shock treatments. Fitting a broad range of models and comparing them using the Akaike information criterion revealed a large heterogeneity of effects. A bell-shaped curve was often observed in the response of the diatoms to temperature changes, while their growth tended to decrease with increasing electrical conductivity. C. meneghiniana was more tolerant to temperature, whilst C. incurvata and C. meneghiniana were the most sensitive to salinity changes. Empirical modelling revealed interactive effects of temperature and salinity on the slope and the breadth of response curves. Contrasting types of interactions indicates uncertainties in the estimation by empirical modelling.

Salinization and warming are of increasing concern for freshwater ecosystems. Interactive effects of stressors are often studied in bifactorial, two-level experimental setups. The shape of environmental reaction norms and the position of the "control" conditions along them, however, can influence the sign and magnitude of individual responses as well as interactive effects. We empirically model binary-stressor effects in the form of three-dimensional reaction norm surfaces. We monitored the growth of clonal cultures of six freshwater diatoms, Cymbella cf. incurvata, Nitzschia linearis, Cyclotella meneghiniana, Melosira varians, Ulnaria acus, and Navicula gregaria at various temperature (up to 28 °C) and salinity (until the growth ceased) shock treatments. Fitting a broad range of models and comparing them using the Akaike information criterion revealed a large heterogeneity of effects. A bell-shaped curve was often observed in the response of the diatoms to temperature changes, while their growth tended to decrease with increasing electrical conductivity. C. meneghiniana was more tolerant to temperature, whilst C. incurvata and C. meneghiniana were the most sensitive to salinity changes. Empirical modelling revealed interactive effects of temperature and salinity on the slope and the breadth of response curves. Contrasting types of interactions indicates uncertainties in the estimation by empirical modelling. [ABSTRACT FROM AUTHOR]

Over time, the average global temperature has varied greatly, mainly due to natural phenomena. However, several anthropic activities have caused significant changes in the Earth's atmosphere, so that various greenhouse gases, especially CO2, have increased their atmospheric concentration and, consequently, produced an increase in the planet's temperature. These climatic changes, particularly global warming, can affect organisms in continental aquatic environments, including primary producers (e.g., macrophytes). Using photosynthetic parameters calculated from chlorophyll a fluorescence and measurements of chlorophyll a content, we assessed the potential effects of temperature increases predicted by two future scenarios from the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC), Representative Concentration Pathway 4.5 (RCP 4.5) and Representative Concentration Pathway 8.5 (RCP 8.5), on the photosynthetic responses of five aquatic macrophytes from tropical lotic ecosystems. Our results showed a trend of a reduction in the φPSII values associated, as a rule, with an increase in the heat dissipation values in the reaction centers of photosystem II, that is, parameter E. Such reductions in the φPSII associated with increases in parameter E suggest that most likely, even the less severe RCP scenario, RCP 4.5, is already sufficient to negatively and significantly affect the photosynthetic responses of most aquatic macrophytes tested in this experimental study. Considering that macrophytes, alongside macroalgae and periphyton, form the basis of autotrophic food webs in tropical lotic ecosystems, our results suggest that there is a real possibility that the negative effects produced by global warming on these primary producers are propagated, as a "cascade effect", indirectly affecting higher trophic levels as well. [ABSTRACT FROM AUTHOR]

BioIntertidal Mapper is a user-friendly tool, with a graphical user interface, that automates the selection and processing of Sentinel-2 imagery, to generate intertidal habitat maps. The software uses Google Earth Engine API and the WorldTides API to select imagery acquired at low tide within a specified timeframe. These images are subsequently processed to calculate a Normalized Difference Vegetation Index, which is masked, based on a shapefile defining the area of interest. Maps are exported to a Google Drive folder. The program offers a simple solution for scientific and environmental manager to map intertidal habitats using free and publicly available satellite imagery.

Navicula sp., a type of benthic diatom, plays a crucial role in the carbon cycle as a widely distributed algae in water bodies, making it an essential primary producer in the context of global carbon neutrality. However, using erythromycin (ERY) and levofloxacin (LEV) in medicine, livestock, and aquaculture has introduced a new class of pollutants known as antibiotic pollutants, which pose potential threats to human and animal health. This study aimed to investigate the toxic effects of ERY and LEV, individually or in combination, on the growth, antioxidant system, chlorophyll synthesis, and various cell osmotic pressure indexes (such as soluble protein, proline, and betaine) of Navicula sp. The results indicated that ERY (1 mg/L), LEV (320 mg/L), and their combined effects could inhibit the growth of Navicula sp. Interestingly, the combination of these two drugs exhibited a time-dependent effect on the chlorophyll synthesis of Navicula sp., with ERY inhibiting the process while LEV promoted it. Furthermore, after 96 h of exposure to the drugs, the activities of GSH-Px, POD, CAT, and the contents of MDA, proline, and betaine increased. Conversely, the actions of GST and the contents of GSH and soluble protein decreased in the ERY group. In the LEV group, the activities of POD and CAT and the contents of GSH, MDA, proline, and betaine increased, while the contents of soluble protein decreased. Conversely, the mixed group exhibited increased POD activity and contents of GSH, MDA, proline, betaine, and soluble protein. These findings suggest that antibiotics found in pharmaceutical and personal care products (PPCPs) can harm primary marine benthic eukaryotes. The findings from the research on the possible hazards linked to antibiotic medications in aquatic ecosystems offer valuable knowledge for ensuring the safe application of these drugs in environmental contexts. [ABSTRACT FROM AUTHOR]

Agriculture, forestry, fisheries, and aquaculture are activities in the primary sectors that are core sectors of the European bioeconomy. However, they have not been considered sufficiently in the bioeconomy policy framework, and neglecting the needs of actors in these sectors could have serious implications for sustainability. Against the background that the updated EU bioeconomy strategy underlines the deployment of inclusive bioeconomies, this paper examines different meanings of inclusive bioeconomies for primary producers by combining a topic modeling of European bioeconomy strategies and a storyline analysis regarding their inclusion in the EU and German bioeconomy strategies. Our analysis reveals four storylines for the inclusion of primary producers, including yield improving technologies, involvement in rural bioeconomy development, support for ecosystem-based practices, and international development. The storylines underscore the distribution of resources, and the inclusion of primary producers is considered a minor goal of the bioeconomy. While the EU strategy seeks to support local value chain development and environment-friendly practices over time, the German strategy gives importance to yield improving technologies. Ensuring consistency between and across strategies at EU and national levels is necessary for reaching the goal of an inclusive bioeconomy with primary producers in consideration. [ABSTRACT FROM AUTHOR]

The availability of underwater light, as primary energy source for all aquatic photoautotrophs, is (and will further be) altered by changing precipitation, water turbidity, mixing depth, and terrestrial input of chromophoric dissolved organic matter (CDOM). While experimental manipulations of CDOM input and turbidity are frequent, they often involve multiple interdependent changes (light, nutrients, C‐supply). To create a baseline for the expected effects of light reduction alone, we performed a weighted meta‐analysis on 240 published experiments (from 108 studies yielding 2500 effect sizes) that directly reduced light availability and measured marine autotroph responses. Across all organisms, habitats, and response variables, reduced light led to an average 23% reduction in biomass‐related performance, whereas the effect sizes on physiological performance did not significantly differ from zero. Especially, pigment content increased with reduced light, which indicated a strong physiological plasticity in response to diminished light. This acclimation potential was also indicated by light reduction effects minimized if the experiments lasted longer. Nevertheless, the performance (especially biomass accrual) was reduced the more the less light intensity remained available. Light reduction effects were also more negative at higher temperatures if ambient light conditions were poor. Macrophytes or benthic systems were more negatively affected by light reduction than microalgae or plankton systems, especially in physiological responses were microalgae and plankton showed slightly positive responses. Otherwise, the effect magnitudes remained surprisingly consistent across habitats and aspects of experimental design. Therefore, the strong observed log–linear relationship between remaining light and autotrophic performance can be used as a baseline to predict marine primary production in future light climate. [ABSTRACT FROM AUTHOR]

Coastal infrastructure has reduced habitat complexity and altered light regimes compared to natural habitats, altering ecological communities and reducing overall biodiversity. Although, many studies have assessed effects of infrastructure on the overall biodiversity, these were often restricted in scope, by assessing only a particular type of infrastructure, such as coastal defence structures, or by focusing solely on diversity metrics. Therefore, we still have little knowledge on the functional impacts of infrastructure, in general, on coastal habitats. To address this knowledge gap, we conducted a systematic review and meta-analysis comparing the functional composition of natural and artificial marine habitats. We analysed a total of 68 publications from 26 countries, with data collected between 1995–2019. We found up to 60% more habitat-forming algae on natural habitats than on infrastructure at most tidal heights, but no differences were found when looking at all species of macro-algal, i.e. including non-habitat-formers. In contrast, we found more habitat-forming filter feeders, such as oysters and mussels, on subtidal vertical and floating structures, such as pylons and pontoons, respectively, than on natural habitats. Differences on the abundance of grazers varied with tidal height and/or the type of infrastructure. For example, in the subtidal, grazers were significantly more abundant on natural boulders than on infrastructure, while at low tidal heights, we found significantly less grazers on artificial floating structures and on vertical structures than on natural habitats. With coastal development on the rise, these differences have significant implications for productivity, energy and nutrient flow in coastal systems. Our findings highlight the importance of adopting a functional approach to have a more holistic understanding on the environmental impacts associated to marine urbanisation and thus better inform management and restoration efforts.

Trends and ecological consequences of phosphorus (P) decline and increasing nitrogen (N) to phosphorus (N:P) ratios in rivers and estuaries are reviewed and discussed. Results suggest that re‐oligotrophication is a dominant trend in rivers and estuaries of high‐income countries in the last two–three decades, while in low‐income countries widespread eutrophication occurs. The decline in P is well documented in hundreds of rivers of United States and the European Union, but the biotic response of rivers and estuaries besides phytoplankton decline such as trends in phytoplankton composition, changes in primary production, ecosystem shifts, cascading effects, changes in ecosystem metabolism, etc., have not been sufficiently monitored and investigated, neither the effects of N:P imbalance. N:P imbalance has significant ecological effects that need to be further investigated. There is a growing number of cases in which phytoplankton biomass have been shown to decrease due to re‐oligotrophication, but the potential regime shift from phytoplankton to macrophyte dominance described in shallow lakes has been documented only in a few rivers and estuaries yet. The main reasons why regime shifts are rarely described in rivers and estuaries are, from one hand the scarcity of data on macrophyte cover trends, and from the other hand physical factors such as peak flows or high turbidity that could prevent a general spread of submerged macrophytes as observed in shallow lakes. Moreover, re‐oligotrophication effects on rivers may be different compared to lakes (e.g., lower dominance of macrophytes) or estuaries (e.g., limitation of primary production by N instead of P) or may be dependent on river/estuary type. We conclude that river and estuary re‐oligotrophication effects are complex, diverse and still little known, and in some cases are equivalent to those described in shallow lakes, but the regime shift is more likely to occur in mid to high‐order rivers and shallow estuaries. [ABSTRACT FROM AUTHOR]

Purpose: It is crucial to understand the micro‐level personal factors that impact farmer mental health help‐seeking, given that farmers are at increased risk of suicide yet show reduced mental health help‐seeking behaviors. Methods: Ten farmers, 10 farmers' partners, and 8 general practitioners (ie, family physicians) from Australia completed qualitative semi‐structured interviews. Braun and Clarke's method of thematic analysis was used to analyze the data. Findings: The analysis resulted in 4 themes: "mental health literacy," "stigma of mental illness and help‐seeking," "support, the partners' role in help‐seeking," and "the intersectionality between being a farmer, age, and gender." Farmers' knowledge and understanding of mental health and treatments was varied. Stigma was reported to be reducing, but still present toward both mental illness and mental health help‐seeking. Support from a partner was reported to facilitate help‐seeking if delivered tactfully. Lastly, being older and male were reported to negatively impact farmer mental health help‐seeking. Conclusion: The findings contribute to understanding farmer mental health help‐seeking and could inform quantitative research and the development and implementation of interventions to promote mental health help‐seeking in this group. [ABSTRACT FROM AUTHOR]

The microphytobenthos (MPB) is a key determinant of ecological processes occurring in coastal sediments, where it functions as a trophic resource, sediment stabiliser and mediator of nutrient cycling and bentho-pelagic coupling. Endobenthic bioturbators are also important components of coastal sediments, wherein they influence ecosystem functioning principally through high sediment and pore-water manipulation rates. However, understanding of how endobenthic engineer activities influence MPB components, especially in the context of global change processes, is limited. We made use of a factorial mesocosm experiment and an in situ optical tool (BenthoTorch) to quantify responses of cyanobacteria, green-algae, diatoms and total MPB biomass to (1) eutrophic vs mesotrophic and (2) high vs low temperature conditions at increasing densities of sandprawns (Kraussillichirus kraussi). These crustaceans are highly influential endobenthic engineers in southern Africa, being widely distributed in estuaries, lagoons and embayments. Findings from our experiment indicated that total MPB biomass and that of cyanobacteria and diatoms (the dominant constituents of MPB assemblages in mesocosms) decreased from controls to maximum sandprawn-density treatments, but predominantly under low temperature. Sediment boundary roughness increased with sandprawn density, suggesting that sandprawn effects on MPB biomass and that of cyanobacteria and diatoms under low temperature was likely sediment mediated, with deposition of residual burrow sediment to the sediment-water interface reducing microalgal productivity. All MPB metrics declined with high temperature, suggesting a physiological intolerance of the MPB assemblages to upper thermal conditions in our experiment or nutrient limitation due to temperature-induced increases in metabolism. Our findings highlight the potential for rising temperature to reduce MPB biomass, as has been reported for open ocean and lake phytoplankton assemblages. Our results also highlight the functional significance of sandprawns in structuring MPB assemblages in coastal ecosystems, but their sediment-mediated limitation of benthic cyanobacterial biomass may confer a degree of resilience to coastal benthic ecosystems against harmful cyanobacterial blooms. • Global change experiment understanding responses of benthic microalgae to eutrophication, warming and changes in bioturbator density. • Rising temperature depressed microalgal biomass. • Increasing sandprawn density led to a reduction in microalgal biomass. • Cyanobacterial biomass was reduced by sandprawns. • Sandprawns may be import in counteracting benthic cyanobacterial blooms in coastal ecosystems. [ABSTRACT FROM AUTHOR]

The European Commission's European Innovation Partnership for Agricultural Productivity and Sustainability (EIP-AGRI), part of the European Commission's Europe 2020 strategy, aims to 'achieve more and better from less' by bringing together a diversity of innovation actors to harness their combined knowledges to creatively achieve sustainability goals. The creation and novel use of biomaterials remains both a significant challenge and opportunity and bringing together all the relevant actors from primary production through to refinement and processing is anticipated to make progress in bringing into practice pilot operational approaches on the ground. For the bioeconomy, a nascent sector, it is a significant challenge for it to become established; grow; innovate and engage all the relevant actors. It has been noted internationally that primary producers, among other cohorts, remain marginalised from bioeconomy activities, which significantly compromises how inclusive and innovative the bioeconomy is likely to be henceforth. In this context, an interesting case study is the Biorefinery Glas Operational Group (OG), located in Ireland. The OG was a 'small-scale-farmer-led green biorefinery supporting farmer diversification into the circular bioeconomy'. The central research question of this paper concerns the dynamics of farmers' participation in the OG, focusing specifically on how their knowledges shaped the operation of the OG and bioeconomy activities within it. This paper presents a social network graph illustrating the diverse actors involved in the OG, their relative degrees of connectedness to each other, and an overview of the differing levels of actors' influence in the network. Interrogating the roles of different actors further, a lens of power theory is used to explore how farmers' knowledges were used in combination with others' knowledges to shape the development of the OG and innovation within it. The overall conclusion from an analysis of interviews conducted with farmer and non-farmer participants in the OG is that while farmers were highly connected with other members of the OG and viewed their involvement in the OG positively, the level of influence they had in decision-making processes in some areas of the OG was relatively limited. Different types of members of the OG tended to work in a relatively segmented way, with farmers contributing as input suppliers and on the practical side at the farm level, while other members of the OG such as scientists worked on more technical aspects. This paper concludes by providing conclusions and lessons of relevance to innovation-brokers and practitioners, and for the operation of OGs involving farmers elsewhere. [ABSTRACT FROM AUTHOR]

Navicula sp., a type of benthic diatom, plays a crucial role in the carbon cycle as a widely distributed algae in water bodies, making it an essential primary producer in the context of global carbon neutrality. However, using erythromycin (ERY) and levofloxacin (LEV) in medicine, livestock, and aquaculture has introduced a new class of pollutants known as antibiotic pollutants, which pose potential threats to human and animal health. This study aimed to investigate the toxic effects of ERY and LEV, individually or in combination, on the growth, antioxidant system, chlorophyll synthesis, and various cell osmotic pressure indexes (such as soluble protein, proline, and betaine) of Navicula sp. The results indicated that ERY (1 mg/L), LEV (320 mg/L), and their combined effects could inhibit the growth of Navicula sp. Interestingly, the combination of these two drugs exhibited a time-dependent effect on the chlorophyll synthesis of Navicula sp., with ERY inhibiting the process while LEV promoted it. Furthermore, after 96 h of exposure to the drugs, the activities of GSH-Px, POD, CAT, and the contents of MDA, proline, and betaine increased. Conversely, the actions of GST and the contents of GSH and soluble protein decreased in the ERY group. In the LEV group, the activities of POD and CAT and the contents of GSH, MDA, proline, and betaine increased, while the contents of soluble protein decreased. Conversely, the mixed group exhibited increased POD activity and contents of GSH, MDA, proline, betaine, and soluble protein. These findings suggest that antibiotics found in pharmaceutical and personal care products (PPCPs) can harm primary marine benthic eukaryotes. The findings from the research on the possible hazards linked to antibiotic medications in aquatic ecosystems offer valuable knowledge for ensuring the safe application of these drugs in environmental contexts.

The present-day COVID-19 pandemic has led to the increasing daily use of antimicrobials worldwide. Triclosan is a manmade disinfectant chemical used in several consumer healthcare products, and thus frequently detected in surface waters. In the present work, we aimed to evaluate the effect of triclosan on diatom cell photophysiology, fatty acid profiles, and oxidative stress biomarkers, using the diatom Phaeodactylum tricornutum as a model organism. Several photochemical effects were observed, such as the lower ability of the photosystems to efficiently trap light energy. A severe depletion of fucoxanthin under triclosan application was also evident, pointing to potential use of carotenoid as reactive oxygen species scavengers. It was also observed an evident favouring of the peroxidase activity to detriment of the SOD activity, indicating that superoxide anion is not efficiently metabolized. High triclosan exposure induced high cellular energy allocation, directly linked with an increase in the energy assigned to vital functions, enabling cells to maintain the growth rates upon triclosan exposure. Oxidative stress traits were found to be the most efficient biomarkers as promising tools for triclosan ecotoxicological assessments. Overall, the increasing use of triclosan will lead to significant effects on the diatom photochemical and oxidative stress levels, compromising key roles of diatoms in the marine system. [ABSTRACT FROM AUTHOR]

Autotrophs play an essential role in the cycling of carbon and nutrients, yet disease‐ecosystem relationships are often overlooked in these dynamics. Importantly, the availability of elemental nutrients like nitrogen and phosphorus impacts infectious disease in autotrophs, and disease can induce reciprocal effects on ecosystem nutrient dynamics. Relationships linking infectious disease with ecosystem nutrient dynamics are bidirectional, though the interdependence of these processes has received little attention. We introduce disease‐mediated nutrient dynamics (DND) as a framework to describe the multiple, concurrent pathways linking elemental cycles with infectious disease. We illustrate the impact of disease–ecosystem feedback loops on both disease and ecosystem nutrient dynamics using a simple mathematical model, combining approaches from classical ecological (logistic and Droop growth) and epidemiological (susceptible and infected compartments) theory. Our model incorporates the effects of nutrient availability on the growth rates of susceptible and infected autotroph hosts and tracks the return of nutrients to the environment following host death. While focused on autotroph hosts here, the DND framework is generalizable to higher trophic levels. Our results illustrate the surprisingly complex dynamics of host populations, infection patterns, and ecosystem nutrient cycling that can arise from even a relatively simple feedback between disease and nutrients. Feedback loops in disease‐mediated nutrient dynamics arise via effects of infection and nutrient supply on host stoichiometry and population size. Our model illustrates how host growth rate, defense, and tissue chemistry can impact the dynamics of disease–ecosystem relationships. We use the model to motivate a review of empirical examples from autotroph–pathogen systems in aquatic and terrestrial environments, demonstrating the key role of nutrient–disease and disease–nutrient relationships in real systems. By assessing existing evidence and uncovering data gaps and apparent mismatches between model predictions and the dynamics of empirical systems, we highlight priorities for future research intended to narrow the persistent disciplinary gap between disease and ecosystem ecology. Future empirical and theoretical work explicitly examining the dynamic linkages between disease and ecosystem ecology will inform fundamental understanding for each discipline and will better position the field of ecology to predict the dynamics of disease and elemental cycles in the context of global change. [ABSTRACT FROM AUTHOR]

The littoral and limnetic phytoplankton of ‘soft and de-mineralized water’ in the Nongmahir reser-voir of Meghalaya state of northeast India (NEI) reveal a fairly diverse assemblage of a total of 52 species, depict a higher richness of Chlorophyta and desmids, and record a speciose constellation of 51 species per sample. Phytoplankton form a dominant quantitative component of net plankton and indicate the differential spatial dominance of important groups. Bacillariophyta > Chlorophyta indicate dominance in the littoral region and Chlorophyta records dominance in the limnetic re-gion. Staurastrum spp. > Cosmarium spp. are important in the two regions. Seventeen ‘specialist’ species collectively contribute to phytoplankton abundance in the littoral (87.9±6.9%) and limnetic (91.6±3.3%) regions and the rest depict a ‘generalist’ nature. Phytoplankton records moderate species diversity and variations of dominance and evenness. The spatial monthly variations of com-position, richness, similarities, abundance, diversity indices and influence of individual abiotic fac-tors are hypothesised to differences in habitat heterogeneity amongst the two regions. The CCA registers 78.36 and 78.95% cumulative influence of 10 abiotic factors on the littoral and limnetic phytoplankton assemblages, respectively. Our results highlight distinct temporal variations of di-versity parameters in comparison with the preliminary survey of June 1995–May 1996. This study is an important contribution to phytoplankton diversity of the reservoirs of India and the subtropical reservoirs in particular.

The simultaneous limitation of productivity by two or more nutrients, commonly referred to as nutrient co-limitation, affects microbial communities throughout the marine environment and is of profound importance because of its impacts on various biogeochemical cycles. Multiple types of co-limitation have been described, enabling distinctions based on the hypothesized mechanisms of co-limitation at a biochemical level. These definitions usually pertain to individuals and do not explicitly, or even implicitly, consider complex ecological dynamics found within a microbial community. However, limiting and co-limiting nutrients can be produced in situ by a subset of microbial community members, suggesting that interactions within communities can underpin co-limitation. To address this, we propose a new category of nutrient co-limitation, community interaction co-limitation (CIC). During CIC, one part of the community is limited by one nutrient, which results in the insufficient production or transformation of a biologically produced nutrient that is required by another part of the community, often primary producers. Using cobalamin (vitamin B12) and nitrogen fixation as our models, we outline three different ways CIC can arise based on current literature and discuss CIC’s role in biogeochemical cycles. Accounting for the inherent and complex roles microbial community interactions play in generating this type of co-limitation requires an expanded toolset – beyond the traditional approaches used to identify and study other types of co-limitation. We propose incorporating processes and theories well-known in microbial ecology and evolution to provide meaningful insight into the controls of community-based feedback loops and mechanisms that give rise to CIC in the environment. Finally, we highlight the data gaps that limit our understanding of CIC mechanisms and suggest methods to overcome these and further identify causes and consequences of CIC. By providing this framework for understanding and identifying CIC, we enable systematic examination of the impacts this co-limitation can have on current and future marine biogeochemical processes.

European small‐scale fisheries are confronted with several challenges, notably a decrease in the number of people engaged in capture fishing, growing competition from less expensive extra‐European Union markets, rising operational costs, strict regulations and the depletion of fishing stocks. Many small‐scale fishers must adapt to change to maintain or increase their income using different business strategies. In this respect, we argue that new and diversified institutional arrangements combined with building social capital can help reach long‐term economic sustainability for small‐scale fisheries businesses, as well as the social‐ecological resilience of coastal areas. In order to understand and analyse the multiplicity of strategies applied by small‐scale fishers–including expansion towards non–productivist activities, this article examines the role of new institutional arrangements based on small‐scale, traditional, quality‐orientated, multifunctional business strategies and non‐fishing activities. Using a case‐study approach, we analyse–in three different European fishery contexts (Greece, Italy and the UK)–how the interplay between building adaptive arrangements and the creation of social capital in selected small‐scale fisheries provides relevant prerequisites for resilience. [ABSTRACT FROM AUTHOR]

Abstract Increasing fish consumption along with rising competition in the global seafood market has brought fisheries and aquaculture producers to adopt several differentiation and marketing strategies. Labelling schemes were thus introduced to respond to a growing demand for traceable and sustainable products. However, the proliferation of quality labels brought to general confusion, calling for collective and public fish labels to ease decision-making. In our case study region (Tuscany, Italy), a number of policy-driven efforts were deployed for establishing regional labelling schemes for fisheries products with no observable impact on the market. Meanwhile, local companies have implemented a number of successful private and regional labels. The purpose of this research is to contribute to potential options for collective regional labelling schemes of fisheries and aquaculture products, through a case study analysis, building on agro-food value-chain and management approaches. Our empirical results highlight key issues and perspectives on labelling policies for local fisheries and aquaculture products.

Abyssal plains cover more than half of Earth's surface, and the main food source in these ecosystems is phytodetritus, mainly originating from primary producers in the euphotic zone of the ocean. Global climate change is influencing phytoplankton abundance, productivity, and distribution. Increasing importance of picoplankton over diatom as primary producers in surface oceans (especially projected for higher latitudes) is projected and hence altering the quantity of organic carbon supplied to the abyssal seafloor as phytodetritus, consequences of which remain largely unknown. Here, we investigated the in situ responses of abyssal biota from viruses to megafauna to different types of phytoplankton input (diatoms or cyanobacteria which were labeled with stable isotopes) at equatorial (oligotrophic) and temperate (eutrophic) benthic sites in the Pacific Ocean (1°N at 4277 m water depth and 39°N at 5260 m water depth, respectively). Our results show that meiofauna and macrofauna generally preferred diatoms as a food source and played a relatively larger role in the consumption of phytodetritus at higher latitudes (39°N). Contrarily, prokaryotes and viruses showed similar or even stronger responses to cyanobacterial than to diatom supply. Moreover, the response of prokaryotes and viruses was very rapid (within 1–2 days) at both 1°N and 39°N, with quickest responses reported in the case of cyanobacterial supply at higher latitudes. Overall, our results suggest that benthic deep‐sea eukaryotes will be negatively affected by the predicted decrease in diatoms in surface oceans, especially at higher latitudes, where benthic prokaryotes and viruses will otherwise likely increase their quantitative role and organic carbon cycling rates. In turn, such changes can contribute to decrease carbon transfer from phytodetritus to higher trophic levels, with strong potential to affect oceanic food webs, their biodiversity and consequently carbon sequestration capacity at the global scale. [ABSTRACT FROM AUTHOR]

The post-Great War Soldier Settlement Scheme, a tragic failure for many of the soldier settlers and their families, resulted in huge financial losses for the governments of the day. Less understood is how the Scheme in Queensland impacted the wider community beyond the settlers and their families. This article explains the Scheme's impact on three sections of the wider Queensland community: land owners, other primary producers and local authorities. Drawing on contemporary newspapers and government archival material, this article argues that the Scheme had unintended impacts on members of the wider Queensland community, but those impacts were not always negative. [ABSTRACT FROM AUTHOR]

The present-day COVID-19 pandemic has led to the increasing daily use of antimicrobials worldwide. Triclosan is a manmade disinfectant chemical used in several consumer healthcare products, and thus frequently detected in surface waters. In the present work, we aimed to evaluate the effect of triclosan on diatom cell photophysiology, fatty acid profiles, and oxidative stress biomarkers, using the diatom Phaeodactylum tricornutum as a model organism. Several photochemical effects were observed, such as the lower ability of the photosystems to efficiently trap light energy. A severe depletion of fucoxanthin under triclosan application was also evident, pointing to potential use of carotenoid as reactive oxygen species scavengers. It was also observed an evident favouring of the peroxidase activity to detriment of the SOD activity, indicating that superoxide anion is not efficiently metabolized. High triclosan exposure induced high cellular energy allocation, directly linked with an increase in the energy assigned to vital functions, enabling cells to maintain the growth rates upon triclosan exposure. Oxidative stress traits were found to be the most efficient biomarkers as promising tools for triclosan ecotoxicological assessments. Overall, the increasing use of triclosan will lead to significant effects on the diatom photochemical and oxidative stress levels, compromising key roles of diatoms in the marine system.

The suicide rate of farmers is approximately double that of the general Australian population, yet farmers employ fewer help-seeking behaviours (Arnautovska et al. in Soc Psychiatry Psychiatr Epidemiol 49:593–599, 2014; Brew et al. in BMC Public Health 16:1–11, 2016). Therefore, it is crucial to understand if, and how health services and system might influence farmer help-seeking. To shed light on this, the current study employed qualitative semi-structured interviews with 10 farmers, 10 farmers' partners and 8 medical practitioners. Thematic analysis, guided by Braun and Clarke's (Qual Res Psychol 3:77–101, 2006) techniques, was used to analyse the data. Three themes were devised concerning the interaction between farmers and health services, including 'health service interactions', 'services are provided within a complex system' and 'emerging technologies: the users, practitioners, and systems'. The findings underscore the importance of interactions between a farmer and a service provider, with farmers wanting their provider to have an understanding of farming life. Help-seeking was also shaped by access, availability, and practitioner constancy. Lastly, a complex relationship between digital mental health services and farmer help-seeking was reported, with factors related to the farmers, the practitioners and the infrastructure/systems discussed. The outcomes have implications for health service and policy reform, developing and providing interventions for farmers to promote health services interaction as a way of mental health help-seeking. [ABSTRACT FROM AUTHOR]

Changes in the ecological stoichiometry of primary producers may have considerable implications for energy and matter transfer in food webs. We hypothesized that nutrient enrichment shifts the trophic position of omnivores towards herbivory, as the nutritional quality of primary producers increases. This hypothesis was tested by analyzing the ecological stoichiometry and stable isotope signature of primary producers and a wide range of aquatic macroinvertebrates, including primary consumers (herbivores) and secondary consumers (both potential omnivores and strict carnivores), along a eutrophication gradient in an agricultural landscape. Our results showed (1) that carbon : nutrient ratios of primary producers decreased along the eutrophication gradient, while the elemental composition of consumers remained homeostatic, and (2) that the trophic position of several omnivores and the generalist predator Notonecta decreased, while the trophic position of most other consumers remained constant. These findings suggest that shifts in the diets of aquatic invertebrates induced by increasing eutrophication may affect species interactions and food web structure in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Estuarine food webs are fueled by multiple different primary producers. However, identifying the relative importance of each producer to consumers is difficult, particularly for fishes that utilize multiple food sources due to both their mobility and their generally high trophic levels. Previous studies have documented broad spatial differences in the importance of primary producers to fishes within the Upper San Francisco Estuary, California, including separation between pelagic and littoral food webs. In this study, we evaluated the importance of primary producers to adult fishes in three closely spaced subregions that represented disparate habitat types (a tidal wetland channel, a turbid backwater channel, and a deep open-water channel), each a potential outcome of local restoration projects. Using stable isotope analysis coupled with a Bayesian mixing model, we identified significant differences in primary-producer contribution to fishes and invertebrates across habitats and seasons, especially in the relative contribution of submersed aquatic vegetation and phytoplankton. Most fishes utilized multiple primary producers and showed little segregation between pelagic and littoral food webs among habitats. Availability of primary producers differs seasonally and across multiple spatial scales, helping to buffer environmental variability and thus enhancing food web resilience. Ecosystem restoration may improve with emphasis on restoring a wide variety of primary producers to support consumers. [ABSTRACT FROM AUTHOR]

Phototrophic protists are a fundamental component of the world's oceans by serving as the primary source of energy, oxygen, and organic nutrients for the entire ecosystem. Due to the high thermal seasonality of their habitat, temperate protists could harbour many well-adapted species that tolerate ocean warming. However, these species may not sustain ecosystem functions equally well. To address these uncertainties, we conducted a 30-day mesocosm experiment to investigate how moderate (12 °C) and substantial (18 °C) warming compared to ambient conditions (6 °C) affect the composition (18S rRNA metabarcoding) and ecosystem functions (biomass, gross oxygen productivity, nutritional quality - C:N and C:P ratio) of a North Sea spring bloom community. Our results revealed warming-driven shifts in dominant protist groups, with haptophytes thriving at 12 °C and diatoms at 18 °C. Species responses primarily depended on the species' thermal traits, with indirect temperature effects on grazing being less relevant and phosphorus acting as a critical modulator. The species Phaeocystis globosa showed highest biomass on low phosphate concentrations and relatively increased in some replicates of both warming treatments. In line with this, the C:P ratio varied more with the presence of P. globosa than with temperature. Examining further ecosystem responses under warming, our study revealed lowered gross oxygen productivity but increased biomass accumulation whereas the C:N ratio remained unaltered. Although North Sea species exhibited resilience to elevated temperatures, a diminished functional similarity and heightened compositional variability indicate potential ecosystem repercussions for higher trophic levels. In conclusion, our research stresses the multifaceted nature of temperature effects on protist communities, emphasising the need for a holistic understanding that encompasses trait-based responses, indirect effects, and functional dynamics in the face of exacerbating temperature changes., Competing Interests: Declaration of competing interest Anika Happe, Marco J. Cabrerizo, Markus Olsson reports financial support was provided by European Commission. If there are other authors, they 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 B.V. All rights reserved.)

Dissolution of anthropogenic CO2 into the oceans results in ocean acidification (OA), altering marine chemistry with consequences for primary, secondary, and tertiary food web producers. Here we examine how OA could affect the food quality of primary producers and subsequent trophic transfer to second and tertiary producers. Changes in food quality induced by OA are often related to secondary metabolites in primary producers, such as enriched phenolics in microalgae and iodine in brown algae. These biomolecules can then be transferred to secondary producers, potentially affecting seafood quality and other marine ecosystem services. Furthermore, shifts in dominant functional groups of primary producers under the influence of OA would also impact higher trophic levels through food web interactions. It is challenging to understand how these complex food chain effects of OA may be expressed under the influence of fluctuating environments or multiple drivers, and how these effects can be scaled up through marine food webs to humans.

Worldwide, the addition of treated wastewater (i.e. effluent) to streams is becoming more common as urban populations grow and developing countries increase their use of wastewater treatment plants. Release of treated effluent can impair water quality and ecological communities, but also could help restore flow and maintain aquatic habitat in water‐stressed regions. To assess this range of potential outcomes, we conducted a global review of studies from effluent‐fed streams to examine the impacts of effluent on water quality and aquatic and riparian biota.We identified 147 quantitative studies of effluent‐fed streams, most of which were from the U.S.A. and Europe. Over 85% of the studies identified water quality as a primary study focus, including basic physical and chemical parameters, as well as trace organic contaminants. Nearly 60% of the studies had at least some focus on aquatic or riparian biota, primarily fish, aquatic invertebrates, and basal resources (e.g. algae).Effluent inputs generally impaired water quality near discharge points, mainly through increased water temperature, nutrients, and concentrations of trace organic contaminants, but also via decreased dissolved oxygen levels. The majority of ecological studies found that basal resources, aquatic invertebrates, and fish were negatively affected in a variety of ways (e.g. biodiversity losses, replacement of sensitive with tolerant species). However, several studies showed the importance of effluent in providing environmental flows to streams that had been dewatered by anthropogenic water withdrawals, especially in semi‐arid and arid regions.Knowledge gaps identified include the abiotic impacts of effluent, such as changes in channel morphology and hydrology (e.g. how nutrient‐rich and warmer effluent affects infiltration rates or interactions with groundwater), the effects of effluent on plants and vertebrates (e.g. amphibians, birds), and the impact of effluent‐induced perennialisation on naturally intermittent or ephemeral streams.Although effluent‐fed streams often exhibit signs of ecological impairment, there is great potential for these systems to serve as refuges of aquatic biodiversity and corridors of ecological connectivity when wastewater treatment standards are high, especially in semi‐arid and arid regions where natural streams have been dewatered. [ABSTRACT FROM AUTHOR]

Amidst the global biodiversity crisis, identifying general principles for variation of biodiversity remains a key challenge. Scientific consensus is limited to a few macroecological rules, such as species richness increasing with area, which provide limited guidance for conservation. In fact, few agreed ecological principles apply at the scale of sites or reserve management, partly because most community‐level studies are restricted to single habitat types and species groups. We used the recently proposed ecospace framework and a comprehensive data set for aggregating environmental variation to predict multi‐taxon diversity. We studied richness of plants, fungi and arthropods in 130 sites representing the major terrestrial habitat types in Denmark. We found the abiotic environment (ecospace position) to be pivotal for the richness of primary producers (vascular plants, mosses and lichens) and, more surprisingly, little support for ecospace continuity as a driver. A peak in richness at intermediate productivity adds new empirical evidence to a long‐standing debate over biodiversity responses to productivity. Finally, we discovered a dominant and positive response of fungi and insect richness to organic matter accumulation and diversification (ecospace expansion). Two simple models of producer and consumer richness accounted for 77% of the variation in multi‐taxon species richness suggesting a significant potential for generalization beyond individual species responses. Our study widens the traditional conservation focus on vegetation and vertebrate populations unravelling the importance of diversification of carbon resources for diverse heterotrophs, such as fungi and insects. [ABSTRACT FROM AUTHOR]

Thiamin (vitamin B1) is primarily produced by bacteria and phytoplankton in aquatic food webs and transferred by ingestion to higher trophic levels. However, much remains unknown regarding production, content and transfer of this water-soluble, essential micronutrient. Hence, the thiamin content of six phytoplankton species from different taxa was investigated, along with the effect of thiamin amendment on thiamin content. Furthermore, thiamin transfer to copepods was estimated in feeding experiments. Prey type, not phytoplankton thiamin content per se , was the most important factor for the transfer of thiamin, as it was lowest from filamentous Cyanophyceae and highest from more easily ingested prey like Dunaliella tertiolecta and Rhodomonas salina. Cyanophyceae had the highest thiamin content of the investigated species, eightfold higher than the lowest. Phytoplankton varied in thiamin content related to the supply of thiamin, where thiamin addition enabled higher thiamin content in some species, while copepod thiamin content was less variable. In all, thiamin transfer is not only dependent on the prey thiamin content, but also the edibility and/or digestibility is of importance. Thiamin is essential for all organisms, and this study constitutes an important building block to understanding the dynamics and transfer of thiamin in the aquatic food web. [ABSTRACT FROM AUTHOR]

Increasing fish consumption along with rising competition in the global seafood market has brought fisheries and aquaculture producers to adopt several differentiation and marketing strategies. Labelling schemes were thus introduced to respond to a growing demand for traceable and sustainable products. However, the proliferation of quality labels brought to general confusion, calling for collective and public fish labels to ease decision-making. In our case study region (Tuscany, Italy), a number of policy-driven efforts were deployed for establishing regional labelling schemes for fisheries products with no observable impact on the market. Meanwhile, local companies have implemented a number of successful private and regional labels. The purpose of this research is to contribute to potential options for collective regional labelling schemes of fisheries and aquaculture products, through a case study analysis, building on agro-food value-chain and management approaches. Our empirical results highlight key issues and perspectives on labelling policies for local fisheries and aquaculture products. [ABSTRACT FROM AUTHOR]

Microalgae are widely used as representative primary producers in ecotoxicology, while macrophytes are much less studied. Here we compared the bioavailability and cellular toxicity pathways of 2 h-exposure to 10−6 mol L−1 Cu in the macrophyte Elodea nuttallii and the green microalga Chlamydomonas reinhardtii. Uptake rate was similar but faster in the algae than in the macrophyte, while RNA-Sequencing revealed a similar number of regulated genes. Early-regulated genes were congruent with expected adverse outcome pathways for Cu with Gene Ontology terms including gene regulation, energy metabolism, transport, cell processes, stress, antioxidant metabolism and development. However, the gene regulation level was higher in E. nuttallii than in C. reinhardtii and several categories were more represented in the macrophyte than in the microalga. Moreover, several categories including oxidative pentose phosphate pathway (OPP), nitrate metabolism and metal handling were only found for E. nuttallii , whereas categories such as cell motility, polyamine metabolism, mitochondrial electron transport and tricarboxylic acid cycle (TCA) were unique to C. reinhardtii. These differences were attributed to morphological and metabolic differences and highlighted dissimilarities between a sessile and a mobile species. Our results highlight the efficiency of transcriptomics to assess early molecular responses in biota, and the importance of studying more aquatic plants for a better understanding on the impact and fate of environmental contaminants. Image 1 • Cu bioavailability and cellular toxicity pathways were compared. • Cu accumulation was similar but faster in the algae than in the macrophyte. • Similar number of genes was regulated in both species. • Higher fold-changes and different gene categories were observed in the macrophyte. • Differences reflect morphological and metabolic characteristics of each species. Cu accumulation is faster in the algae, but greater transcriptome response occurred in the macrophyte. [ABSTRACT FROM AUTHOR]

Abstract Microplastics are persistent contaminants accumulating in the environment. Aquatic ecosystems have been studied worldwide, revealing ubiquitous contamination with microplastics. Microalgae, one of the most important primary producers in aquatic ecosystems, could suffer from microplastic contamination, leading to larger impacts on aquatic food webs. Nonetheless, little is known about the toxic effects of microplastics on microalgae populations. Thus, the objective of this review was to identify these effects and the impacts of microplastics on microalgae populations based on currently available literature, also identifying knowledge gaps. Even though microplastics seem to have limited effects on parameters such as growth, chlorophyll content, photosynthesis activity and reactive oxygen species (ROS), current environmental concentrations are not expected to induce toxicity. Even so, microplastics could disrupt population regulation mechanisms, by reducing the availability or absorption of nutrients (bottom-up) or reducing the population of predator species (top-down). Microplastics' properties can also influence the effects on microalgae, with smaller sizes and positive surface charges having higher toxicity. Therefore, more research is needed to better understand the effects of microplastics on microalgae, such as adaptation strategies, effects on population dynamics and microplastics properties influencing toxicity. Graphical abstract Unlabelled Image Highlights • Microplastics' current concentrations are not expected to directly harm microalgae. • Microplastics may inhibit predation or reduce nutrient availability in microalgae. • Factors responsible for species sensitivity and microplastics toxicity are unclear. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the interactions between primary producers and consumers plays an important role for the conservation of sensitive ecosystems such as lagoons. In this light, we studied the relationships between the flocks' size of Mareca penelope and the distribution of three seagrass species (Cymodocea nodosa, Zoostera marina and Nanozostera noltei) occurring in the Marano and Grado lagoon (Northern Adriatic Sea). Twelve bird monitoring areas were monthly surveyed for 3 years whereas seagrass distribution data were collected for the whole lagoon in the following years. The overall number of individuals of M. penelope was related to seagrass meadow extension and species cover by using a multiscale approach in four circle buffers (with radius of 500, 750, 1,000 and 1,250 m). Among the considered scales, the 750 m radius scale showed the best performance. The overall number of M. penelope increased where the occupied area by seagrass meadows was larger. Results also showed that when C. nodosa mean percentage cover increased the number of M. penelope decreased, while if N. noltei mean percentage cover increased also M. penelope number increased. Z. marina showed a negligible influence for all the tested scales. Our findings demonstrate that M. penelope populations depend not only on the extension of seagrass meadows but also on their species assembly, evidencing that M. penelope seem to prefer N. noltei stands, avoiding meadows with high abundance of C. nodosa. Our aim was to analyse the relationships between the flocks' size of Mareca penelope and the distribution of three seagrass species (Cymodocea nodosa, Zoostera marina and Nanozostera noltei) occurring in the Marano and Grado lagoon (Northern Adriatic Sea). Our findings demonstrate that M. penelope populations depend not only on the extension of seagrass meadows but also on their species assembly. [ABSTRACT FROM AUTHOR]

Abstract This paper presents an analysis of the diversification and non-productivist practices and strategies deployed by European small-scale fishers vis-à-vis contextual regulatory and market factors. Building on resilience thinking – combined with a qualitative case study approach involving primary producers and associated stakeholders – the strategies of primary producers in two specific contexts are examined: inshore fisheries in Cornwall (UK) and coastal fisheries in Tuscany (Italy). In so doing, the analysis identifies possible adaptation strategies that can help support the sustainability of the fisheries involved. The strategies adopted by fishers include, for example, investing in innovation, reorganising the supply chain, multifunctionality and diversification, and implementing environmentally friendly activities. [ABSTRACT FROM AUTHOR]

The mixing pattern along a summer salinity gradient in the estuary Odense Fjord was evaluated using nutrient concentrations as well as 13C and 15N isotope signatures of suspended and sediment organic matter, immobile macrophytes (Fucus vesiculosus and Ruppia maritima), and benthic fauna (Mya arenaria, Hediste (Nereis) diversicolor, and Arenicola marina). Trophic discrimination (Δ13C and Δ15N) of the infaunal consumers (suspension feeders and detritivores) was assessed from the obtained mixing patterns along the estuarine gradient. Correspondence between salinity, DIC, and DIN in Odense Fjord implies conservative mixing as also evident from linear relationships between salinity and δ13C and δ15N signatures of most living organic pools. Isotope signatures of suspended organic matter (i.e., diatoms) indicate that the river to marine DIC and DIN end-members have daily/weekly δ13C and δ15N averages during summer from − 10 to 0‰ and 10-12 to 0-5‰, respectively. Stable isotope signatures of long-lived macrophytes stationary at specific locations in Odense Fjord showed δ13C levels that were about 7‰ higher than for suspended particles and 3-4‰ higher than for sediment organic matter, while no such difference was evident for δ15N. The food of invertebrate consumers (M. arenaria, H. diversicolor, and A. marina) determined from the estuarine δ13C and δ15N patterns provided the first ever reported trophic discrimination of these animals. Thus, Δ13C was 1.9, 1.6, and 1.3‰ and Δ15N was 4.4, 5.0, and 3.5‰ for the three species, respectively. Accordingly, benthic suspension and deposit feeders in Odense Fjord are largely supported by a diet consisting of benthic and pelagic microalgae, however, with a possible slight shift in diet proportions or to other food sources in the lower reaches of the estuarine gradient. [ABSTRACT FROM AUTHOR]

We present three models representing the trophic and behavioral dynamics of a simple food chain (primary producers, grazers, and predators) at temporal scales shorter than the scale of consumer reproduction, and at the spatial scales typically employed in field experiments. These models incorporate flexible behavioral responses of organisms to their predators and resources in spatially heterogeneous environments that are open to immigration and emigration. The basic models include passive immigration at all trophic levels, producer growth rates and losses to grazer consumption, grazer emigration rate as a behavioral response to producer and predator densities, grazer losses to predator consumption, and predator emigration as a function of grazer density. We model this system as: (1) a set of ordinary differential equations ('well-mixed model'); (2) a set of partial differential equations describing a population of discrete grazers foraging on discrete patches of primary producers ('discrete-grazer model'); and (3) a set of simulation rules describing the movement and foraging of individual grazers and the growth of primary producers on discrete patches in explicit space ('individual-based model'). The ordinary differential-equation models produced similar results to individual-based models with well-mixed producers, and the discrete-grazer and individual-based models produced similar results when grazers possessed a long-term memory of patch reward rates. The well-mixed and discrete-grazer models thus represent specific, limiting cases of the general individual-based model. Multiple equilibria and sustained oscillations are possible but are less likely in the discrete-grazer and individual-based models than in the well-mixed model, because localized foraging of discrete grazers leads to the rapid development of spatial heterogeneity in producer biomass and, hence, to a decrease in overall primary production. All models predict that stable equilibrium densities of all trophic levels increase with enrichment, provided grazers increase their emigration rates as predator density increases. If increasing predator density leads to decreasing grazer-emigration rates, predator and grazer densities increase, but producer biomass may increase or decrease with enrichment. These results contrast with predictions from models that assume ideal free distributions of grazers and/or predators with respect to their resources. Our models also predict that densities at all trophic levels will increase with increasing producer immigration, and that producer density will decline with increasing grazer immigration and increase with increasing predator immigration. Our qualitative findings on enrichment are used to interpret an experiment dealing with the short-term dynamics of a stream community open to grazers and predators.