The aquaculture industry requires good water quality for its successful operation but produces wastes that can cause environmental deterioration and pose high risks to the sector. Adequate waste treatment and recycling are necessary to make aquaculture a sustainable and profitable industry and contribute to the circular economy. Polluted water sources, excess feeding, overstocking, use of antibiotics/chemicals and harmful algal blooms are major causes of water quality deterioration and low production in aquaculture systems. Discharges of untreated wastes would have serious impacts on the receiving water bodies, and eventually on the aquaculture industry itself. Possible solutions include technological innovations in environmentally friendly production systems, use of efficient processes in water quality management and improved legislation and governance. Environmentally feasible aquaculture production technologies such as recycling aquaculture system, integrated multi-trophic aquaculture and aquaponics including features of waste recycling are viable options in aquaculture schemes. Best aquaculture practices integrating advanced water quality treatment processes and technologies, supported by automation and sensors, modeling and artificial intelligence-internet of things are necessary for a sustainable aquaculture environment, production and stable value chain. In general, low-cost technologies for aquaculture waste treatment and environmental impact reduction through good governance are crucial for achieving sustainability in the aquaculture industry and natural environmental management.

Developing low cost and effective phosphate adsorbents is crucial to prevent eutrophication of natural waters. Here, phosphate removal by a natural and abundant shale from the Ivory Coast was investigated in both batch and column experiments with special attention devoted to understand the adsorption process. Batch experiments were carried out to assess the influence of initial phosphate concentration, sorbent dosage, contact time, and pH on phosphate removal. The phosphate removal efficiency increased with increased shale dosage while phosphate uptake decreased. Aqueous Ca, Mg, Al, and Fe species concentrations decreased in the presence of phosphate. Additionally, phosphate uptake strongly decreased with pH increases in the range 2–11, but then increased at pH 12. The kinetics were well described using a pseudo-second order model, and Langmuir adsorption isotherms were used for the equilibrium surface reactions. Adsorption to nanoparticles of goethite was hypothesized to be the major phosphate removal mechanism in the pH range 4–10. Column experiments with a flow rate of 1 mL min−1 and an initial phosphate concentration of 25 mg L−1 showed a breakthrough point at a V/Vp value of ~17, where Vis the volume of phosphate solution added to the column and Vp is the pore volume. A V/Vp value of ~17 corresponded to a phosphate uptake of 0.17 mg/g, which was in agreement with the batch experiments. Column experiments revealed a strong correlation between the aqueous concentrations of Ca, Mg, Al, and Fe species and phosphate removal and, thus, suggest that phosphate removal by the shale occurred by aqueous dissolution/precipitation.

Coastal eutrophication and hypoxia remain a persistent environmental crisis despite the great efforts to reduce nutrient loading and mitigate associated environmental damages. Symptoms of this crisis have appeared to spread rapidly, reaching developing countries in Asia with emergences in Southern America and Africa. The pace of changes and the underlying drivers remain not so clear. To address the gap, we review the up-to-date status and mechanisms of eutrophication and hypoxia in global coastal oceans, upon which we examine the trajectories of changes over the 40 years or longer in six model coastal systems with varying socio-economic development statuses and different levels and histories of eutrophication. Although these coastal systems share common features of eutrophication, site-specific characteristics are also substantial, depending on the regional environmental setting and level of social-economic development along with policy implementation and management. Nevertheless, ecosystem recovery generally needs greater reduction in pressures compared to that initiated degradation and becomes less feasible to achieve past norms with a longer time anthropogenic pressures on the ecosystems. While the qualitative causality between drivers and consequences is well established, quantitative attribution of these drivers to eutrophication and hypoxia remains difficult especially when we consider the social economic drivers because the changes in coastal ecosystems are subject to multiple influences and the cause–effect relationship is often non-linear. Such relationships are further complicated by climate changes that have been accelerating over the past few decades. The knowledge gaps that limit our quantitative and mechanistic understanding of the human-coastal ocean nexus are identified, which is essential for science-based policy making. Recognizing lessons from past management practices, we advocate for a better, more efficient indexing system of coastal eutrophication and an advanced regional earth system modeling framework with optimal modules of human dimensions to facilitate the development and evaluation of effective policy and restoration actions.

Although it is generally known that a combination of abiotic and biotic drivers shapes the distribution and abundance of parasites, our understanding of the interplay of these factors remains to be assessed for most marine host species. The present field survey investigated spatial patterns of richness, prevalence and abundance of parasites in Mytilus galloprovincialis along the coast of the northern Adriatic Sea. Herein, the relationships between biotic (host size, density and local parasite richness of mussel population) and abiotic (eutrophication and salinity) drivers and parasite richness of mussel individuals, prevalence and abundance were analysed. Local parasite richness was the most relevant factor driving parasite species richness in mussel individuals. Prevalence was mainly driven by eutrophication levels in three out of four parasite species analysed. Similarly, abundance was driven mainly by eutrophication in two parasite species. Mussel size, density and salinity had only minor contributions to the best fitting models. This study highlights that the influence of abiotic and biotic drivers on parasite infections in mussels can be differentially conveyed, depending on the infection measure applied, i.e. parasite richness, prevalence or abundance. Furthermore, it stresses the importance of eutrophication as a major factor influencing parasite prevalence and abundance in mussels in the Adriatic Sea.

We investigated whether changes in nutrient availability affected N, P, S and polyphenol concentrations in different leaf-development stages of three brevideciduous and three evergreen dominant woody species in a nutrient-limited savanna woodland in Central Brazil. Treatments included eight years of annual fertilization with 100 kg ha−1 of N, P, N plus P and control, each replicated in four randomized 15 × 15-m plots. All species increased S concentrations (minimum 28%) in young and mature leaves in fertilized plots. Dalbergia miscolobium decreased total phenol concentrations with P (−34.3%, −23.7%) and NP fertilization (−28.2%, −17.1%). Blepharocalyx salicifolius increased total phenol (27.6%, 18.8%) and tannin (46.3%; 43.5%) in P fertilized and increased total phenol (33.9%) and tannin (27.8%, 43.5%) in NP fertilized plots. Total phenol concentration decreased with leaf age in Ouratea hexasperma, Styrax ferrugineus and Blepharocalyx salicifolius, which also decreased tannin concentration with leaf age. For all treatments, brevideciduous species had higher N, P, total phenols and tannin concentrations and lower S concentration than evergreens. These differences between phenological groups suggest that tropical ecosystems responses to environmental changes are more complex than anticipated by global vegetation models, with consequences for predictions in ecosystem functions and resilience.

A survey of the surface-area-normalized dissolution rates of major phosphate bearing minerals shows these rates to vary by >8 orders of magnitude with a general dissolution-rate trend sturvite > britholite ∼ fluoroapatite > variscite > monazite ∼ rhabdophane. This trend reflects the relative strength of the metal-oxygen bonds holding together the phosphate tetrahedra in the mineral structure. Due to the high surface-area-normalized reactivity of fluoroapatite, and the high surface area of natural variscite and rhabdophane, it seems likely that these minerals buffer the concentration of P and the rare-earth elements in many natural waters. As such, the solubility of these minerals plays a significant role in the global phosphorus cycle, and may potentially provide clues for future sustainable phosphorus use.

This paper, based on data from the latest checklist of Italy, analyzes the distribution patterns of rare and common lichen species within biogeographically homogeneous versus heterogeneous areas of Italy, and the relationships with some main drivers of rarity and commonness. The following data were used: 1) commonness-rarity values of 2565 species in nine ecoregions; 2) frequency of 353 nationally rare and 387 nationally common species in 21 administrative regions. The following functional and ecological traits were considered: growth form, photobiont(s), type of reproduction, substrata, bioclimatic range, ecological indicator values for aridity and eutrophication, and poleophoby. Within each ecoregion, rare species by far outweigh common species but about one third of these are common in other ecoregions. At the level of regional floras, rarity is significantly associated with epiphytic substrata, non-trebouxioid photobionts and high air humidity, while commonness is associated with saxicolous substrata, trebouxioid photobionts and eutrophication. Rarity seems to mainly depend on two factors, bioclimate (many rare species are outside the limit of their bioclimatic optima) and reduced availability of suitable habitats (e.g. old-growth forests), while commonness is mainly related to disturbance (eutrophication, creation of drier habitats). Most of the nationally rare lichens belong to an oceanic-suboceanic element with tropical affinities or to a small set of continental species with their optima in the dry steppe biome, which suggests that many rare species can persist in microrefugia, that is sites with microclimates that support small populations of species beyond the boundaries of the climatic limits of their main distributions.

Many parts of the world rely on nutrients like nitrogen and phosphorus to improve farming production and increase yields. There are significant food security as well as socio-economic issues at stake. However, it is also clear that fertilizer loads are particularly damaging to aquatic environments, including lakes, rivers, coral reefs, and wetlands. This article explores governance approaches to fertilizer practices that impact on aquatic environments (eutrophication) by examining a case study of the Great Barrier Reef. Governance involves any and all forms of state and non-state control over a given set of issues. It can include, but is not limited to, rule-based approaches like regulation, although it can also involve market-driven measures like nutrient trading schemes, government grants and other financial incentives. So, which approach to governance works best to combat this particular policy question? What other insights into the design of effective regulation and governance can be gathered? In this article, the authors make three broad arguments for change: firstly, it is crucial that regulation features within government strategies; secondly, there must be a rigorous systematic evaluation of the strategies to ensure that the desired behavioural change is achieved along with the desired outcomes; thirdly, and most importantly, the strategies and the evaluation methods must be appropriate for the culture of the industry they are designed to regulate.

The present study aims to assess the environmental quality of six estuaries in north-eastern Brazil, using biochemical composition and quantity of organic matter in tropical sediments. Samples were collected monthly during spring low tide from August 2011 to July 2012, in the mid-littoral. Concentrations of organic matter and its biochemical composition reflected the degree of anthropogenic pressure. Although total concentrations of proteins and carbohydrates were similar among estuaries with contrasting levels of anthropogenic pressure, the protein to carbohydrates (PRT : CHO) ratio effectively reflected the trophic state of these areas. PRT : CHO ratios >1 were observed in all studied areas suggesting eutrophic conditions or an initial stage of eutrophication in all of them. Low Chl-a/Phaeo ratios may be associated with the level of eutrophication of each area, however it may also reflect the natural productivity or the presence of mangrove debris. These results were compared with those obtained in previous environmental assessments of the same estuarine areas using the AZTI Marine Biotic Index and monitoring reports showing good agreement. The present study confirmed for the first time in tropical estuarine areas that the biochemical approach can be successfully used to assess the trophic state of the benthic compartment.

Efficient phosphorus (P) recycling from rural and urban areas is becoming an increasing issue due to the scarcity of natural P deposits. Based on a life cycle assessment (LCA), we analyzed the environmental performance of 17 different P supply and recycling approaches from urban wastes, biosolids and slaughterhouse wastes compared with the two conventional inorganic fertilizers phosphate rock and triple superphosphate. The results show that many recycled P fertilizers (RPFs; e.g., digestates from urban organic wastes, biosolids and their ashes, meat and bone meal (MBM) and its recycling products) are competitive in terms of LCA results compared with conventional P fertilizers. For each of the P recycling sources, one or more treatment options were identified, which have more favorable LCA results than the conventional references. For sewage sludge, we found that direct application of the stabilized biosolids, and incineration with application of the ash showed the lowest LCA impacts per kg P; their treatments even generated net credits from added values. The same applies for the anaerobic digestion treatment of urban organic wastes. For MBM, low environmental impacts were identified for each of the analyzed treatment options, especially for anaerobic digestion, incineration, feeding with application of manure and direct application. Similarly, low environmental impacts and net credits were found for directly applied biomass ash. Some organically based RPFs demonstrate added values, i.e., as nitrogen and potassium fertilizer effect, energy gains during the treatment, or a humus sequestration potential. If these added values are considered in the LCAs, 11 out of 17 RPFs will have advantageous effects for the majority of addressed impact categories.

Beach ecosystems extend from dune to offshore areas along most coasts, and provide essential services that are not provided by any other ecosystem. Indeed, sandy systems contain unique biodiversity and supply nursery and foraging areas for numerous commercially important marine species, such as flatfish. However, these systems are threatened by increasing anthropogenic pressure. Green tides (GT, i.e. accumulations of green opportunistic macroalgae) are a major human-induced threat to marine ecosystems, from inshore to nearshore. This eutrophication process greatly affects both benthic invertebrate communities and flatfish communities, within sheltered and non- or microtidal systems. However, the responses of dynamic open macrotidal sandy systems to eutrophication in the form of macroalgal mats are not yet fully understood. In particular, understanding the effects of GT on two connected biological compartments (infauna and flatfish) within two connected habitats (intertidal and subtidal) is crucial. Here, we set out to assess the influence of several environmental variables, including Ulva biomass, on the variability in infauna and flatfish communities in both the intertidal and the subtidal at four sites impacted or not by GT. In total, 110 biodiversity samples were analysed with classic and novel analytical approaches. Our results demonstrate that the presence of GT specifically impacts intertidal macroinvertebrate communities. However, small effects of GT on subtidal infauna communities, as well as on species-specific flatfish at both intertidal and subtidal, were still detectable. Our findings underline the vulnerability of highly dynamic ecosystems exposed to anthropogenic stress, in particular intertidal sandy shores.

This study is an attempt to unravel the infection pattern of the Caryophyllaeid tapeworm, Adenoscolex oreini and its association with water quality, planktonic copepods and health traits of fish in a highly stressed lake. Prevalence differed significantly (P < 0·05) among different fish species with highest infection recorded in Schizothorax niger (% = 36·74) compared to Schizothorax esocinus (% = 15·7). Within-lake trophic gradient affected the infection pattern as prevalence of A. oreini was significantly higher (44·62%, P = 0·0001) at hypereutrophic site as compared to least eutrophic site (8·01%). The data suggest that spatial variation in the intensity of A. oreini corresponded to the variation in the abundance of planktonic copepods. The density of Cyclops scutifer was positively correlated with the prevalence of tapeworm. Results indicate that the health condition, which was reflected by condition factor and gonadosomatic index, was lower in parasitized fish, and there seems to be synergistic effect of eutrophication and parasitism on fish health. Linear regression coefficients showed that the health indices were significantly (P < 0·05) predicted by infection intensity. It is concluded from the results that within-lake pollution gradient affects the infection pattern, density of intermediate host and health attributes of fish, and therefore these finding will lead us to elucidate the predictors responsible for decline of health of fish in highly stressed water bodies.

Coastal ecosystems are highly complex and driven by multiple environmental factors. To date we lack scientific evidence for the relative contribution of natural and anthropogenic drivers for the majority of marine habitats in order to adequately assess the role of different stressors across the European seas. Such relationship can be investigated by analysing the correlation between environmental variables and biotic patterns in multivariate space and taking into account non-linearities. Within the framework of the EMBOS (European Marine Biodiversity Observatory System) programme, hard bottom intertidal communities were sampled in a standardized way across European seas. Links between key natural and anthropogenic drivers and hard bottom communities were analysed using Boosted Regression Trees modelling. The study identified strong interregional variability and showed that patterns of hard bottom macroalgal and invertebrate communities were primarily a function of tidal regime, nutrient loading and water temperature (anomalies). The strength and shape of functional form relationships varied widely however among types of organisms (understorey algae composing mostly filamentous species, canopy-forming algae or sessile invertebrates) and aggregated community variables (cover or richness). Tidal regime significantly modulated the effect of nutrient load on the cover and richness of understorey algae and sessile invertebrates. In contrast, hydroclimate was more important for canopy algae and temperature anomalies and hydroclimate separately or interactively contributed to the observed patterns. The analyses also suggested that climate-induced shifts in weather patterns may result in the loss of algal richness and thereby in the loss of functional diversity in European hard bottom intertidal areas.

Policy makers often face the problem of evaluating how water quality affects a region's economic well-being. Using water clarity as a measure of the degree of eutrophication levels (as a lake becomes inundated with nutrients, water clarity decreases markedly), analysis is performed on sales data collected over a six-year period. Our results indicate that water clarity has a significant effect on prices paid for residential properties. Effects of a one-meter change in clarity on property value are also estimated for an average lake in four real estate market areas in New Hampshire, with effects differing substantially by area. Our findings provide state and local policy makers a measure of the cost of water quality degradation as measured by changes in water clarity, and demonstrate that protecting water quality may have a positive effect on property tax revenues.

The small-sized copepod community structure (<1  mm) and its response to environmental variability was examined during an annual cycle in Kalloni Gulf, a semi-enclosed coastal system in the NE Aegean Sea. Α 90 µm net was used in order to adequately sample the smaller copepod fractions. In the copepod ecology the spatial patterns dominated over the seasonal. Total copepod abundance increased towards the inner gulf area while diversity indices followed the opposite trend. The inner gulf copepod assemblage area was affected by the increasing magnitude of eutrophication, characterized by high abundance values, low species richness and dominance of a single species (e.g. Oithona nana). A clear seasonal succession of species was observed, ordered by temperature, salinity, chlorophyll a, heterotrophic bacterial biomass, organic and inorganic nutrients. Freshwater inputs and the subsequent nutrient inflow was a dominant phenomenon enhancing copepod production and negatively affecting the biodiversity of the assemblage. The great contribution of copepod larval stages in the total community and their year-round presence indicate the continuous production of copepods during the annual cycle, highlight the importance of the smaller size fraction and encourage the use of finer mesh-size nets when assessing the structure and dynamics of copepod communities.

The Adriatic Sea, being a semi-closed and shallow basin, is more sensitive to anthropogenic impact than other areas of the Mediterranean Sea. Given the crucial role of meiofauna in the marine ecosystems, temporal series of data on this benthic assemblage are fundamental to give new insights into the health status of this basin. A data set (decade 2002–2012) on the meiofauna of two river mouths (Foglia and Metauro) close to a Natural Park (Monte San Bartolo, Central Adriatic Sea) has been analysed and related to several environmental parameters. In particular, changes in the meiofaunal structure, abundance and diversity have been investigated in order to evaluate possible variations of ecological quality status (EQS), in accordance with the Water Framework Directive. The structure of the meiofaunal assemblage appeared significantly different in the period studied, with a higher abundance of annelids in 2002 and an increase of nematodes in the following sampling campaigns. Among the faunal parameters, the Shannon and Pielou indices suggested a decline of the EQS over time, likely mainly due to the negative effect of chlorophyll-a peaks, which may highlight the influence of eutrophication phenomena and an enhancement of the organic matter supply. The lowering of the EQS of the study area suggests the need to intensify management and conservation efforts in the coastal systems, and supports the use of the meiofaunal assemblage as a useful bioindicator.

Diatoms and geochemical stratigraphy were studied in sediment core samples collected from a heavily polluted urban lake (SE China) in order to track the history of eutrophication and heavy metal contamination. The sediment profile covered ca. 60 years (from ca. 1951 to 2011) based on 137Cs and Spheroidal carbonaceous particles (SCP) dating, and encompassed a period of rapid industrial development in this region. Diatoms experienced two visible shifts, including the replacement of benthic and epiphytic taxa by planktonic species (e.g., Cyclotella meneghiniana Kützing) in 1972, and the dominance of Cyclotella atomus Hustedt and Nitzschia palea (Kützing) W. Smith after 1999. Metals (i.e., Cd, Pb and Zn), total phosphorus, total nitrogen and total organic carbon all increased in the past 60 years. Redundancy analysis was used to correlate diatom with chemical change and explained 50.3–60% of total variation in diatom data for three periods (from 1951 to 1999, between 1951 and 2011 and from 1972 to 2011). The combined effects of nutrients and metals were the predominant factor, capturing 29.6–42.8% of the total variance. Nutrients alone accounted for little more variance than did metals alone for the first flora shift about 1972. The further shift after 1999 was more influenced by the sole effect of metals than that of nutrients. Increases in species (e.g., N. Palea) able to tolerate both nutrient-related and metal-related stressors were related to persistent nutrient and metal inputs. In addition, climate warming might exacerbate eutrophication and metal contamination in this lake.

Bird colonies affect all elements of inhabited ecosystems, such as the soil, floristic composition and phytocoenosis structure, including the lichen biota. To date, the few papers focusing on changes in the composition of lichen vegetation caused by bird colonies are concerned with saxicolous ornithocoprophilous communities. The aim of this study was to define the impact of the grey heron in two breeding colonies on epiphytic lichens on Scots pines presently inhabited by birds, as well as those recently abandoned. Analysis of the lichen biota showed that the species composition and number of lichens were significantly modified in the functioning colony and the post-colony areas when compared with the control plots never inhabited by grey heron. Within the functioning and post-colony areas, mainly species with a wide ecological amplitude and those characteristic of fertile habitats dominated, while acidophilous and ubiquitous taxa occurred in the control plots. Multivariate analyses (for species abundance and ecological characteristics) showed that lichens growing within the functioning colony and post-colony areas differed significantly from those in the control area in their habitat requirements, as they demanded nutrient-rich, low or moderately moist and deacidified bark. Within the control plots, lichens preferring a relatively acidic and slightly nitrified substratum occurred. The direct impact of bird excrement and the fertilized bark could cause significant modifications in qualitative and quantitative species composition compared to the epiphytic lichen biota usually occurring on Scots pines.

A systematic limnological survey of water bodies of Byers Peninsula (Livingston Island, South Shetland Islands) was carried out during the summer of 2001/02. Abundances of microbial plankton were determined which allowed a delineation of the pelagic food web structure. We also report the nutrient status of these lakes. We demonstrate the occurrence of a trophic gradient that extended from upland lakes (oligotrophic) to the coastal ones (eutrophic). The study shows that a lake's morphology regulates the relative importance of the pelagic and benthic habitats, whereas nutrient loads mainly determine its trophic status. Yet, some of the variability observed could be also a legacy of the landscape. Photosynthetic pigments analyses by high-performance liquid chromatography of the lake waters revealed a major occurrence of chlorophytes, chrysophytes and diatoms. The chlorophyll a concentrations in lakes in the central plateau were consistently lower (< 2.5 μg l-1) than coastal sites, which were one order of magnitude higher. Numbers of both bacterioplankton and autotrophic picoplankton also increased from inland to coastal sites. However, the relative role of autotrophic picoplankton in the total phytoplankton assemblage decreased with the increase in nutrients loads. Our results show that the trophic status clearly plays a significant role in structuring the pelagic communities of these lakes despite climatic constraints.