Beyond taxonomy: Functional diversity reveals Hidden impacts of urban wastewater on marine-coastal zooplankton.

The lionfish Pterois volitans is an invasive species throughout the Western Atlantic that disturbs functioning of local ecosystems such as coral reefs via fast and intense consumption of small fish and invertebrates. In 2009, lionfish populated the bays of Tayrona National Natural Park (TNNP), a biodiversity hotspot in the Colombian Caribbean that is strongly influenced by changing environmental conditions due to a rainy and dry season. So far, the spatial and temporal distribution of P. volitans in the bays of TNNP is unknown. Therefore, this study assessed the abundance and body lengths of P. volitans during monthly surveys throughout the year 2012 in four bays (thereof two bays where lionfish removals were undertaken) of TNNP at 10 m water depth in coral reefs using transect tools. Findings revealed lionfish abundances of 2.9 ± 0.9 individuals ha−1 with lengths of 20–25 cm for TNNP, hinting to an established, mostly adult local population. Actual TNNP lionfish abundances are thereby very similar to those at Indo–Pacific reef locations where the invasive lionfish formerly originated from. Significant spatial differences for lionfish abundances and body lengths between different bays in TNNP suggest habitat preferences of P. volitans depending on age. Lionfish abundances were highly variable over time, but without significant differences between seasons. Removals could not reduce lionfish abundances significantly during the period of study. This study therefore recommends improved management actions in order to control the already established invasive lionfish population in TNNP.

Decentralized tap water systems are an important drinking water source worldwide. A good quality, high-pressure continuous water supply (CWS) is always the target of any urban settlement. However, tap water in some areas are reported with deteriorated water quality even though treated well before supplying. Such deterioration of tap water quality is reported widely from areas with low water availability and in economically poor countries where water are supplied intermittently (IWS). This study focuses in identifying tap water quality in IWS and causes of water quality degradation using nitrate-nitrogen (NO3-N) as an indicator and stable isotopes of hydrogen (δD) as tracer. Nine water reservoirs and ninety municipal tap water (ten per reservoir) samples were collected during the wet (June–September) and dry (November–February) seasons in the Kathmandu Valley (KV), Nepal. Ten percent of the tap water samples exhibited higher NO3-N than those of their respective reservoirs during the wet season, while 16% exhibited higher concentrations during the dry season. Similarly, the isotopic signatures of tap water exhibited 3% and 23% higher concentrations than those of their respective reservoirs during the wet and dry seasons, respectively. Coupling analysis between NO3-N and δD demonstrates close connection of groundwater and tap water. The results indicate groundwater intrusion as the primary component in controlling tap water quality variations within the same distribution networks during IWS. Meanwhile, the obtained results also indicate probable areas of intrusion in the KV as well as usefulness of δD as a tool in the assessment of tap water systems.

Interpreting the salinization and hydrogeochemical characteristics of groundwater in Dongshan Island, China

Development and short-term dynamics of macrofouling assemblages on fish-cage nettings in a tropical estuary

Biomonitoring is a cheap and effective tool for evaluation of water quality, and infer on the balance of aquatic ecosystems. The benthic macroinvertebrates are bioindicators sensitive to environmental changes, and can assist in detecting and preventing impacts such as organic enrichment and imbalance in the food chain. We compared the structure of benthic communities on artificial substrate samplers located in places near and far from net cages for production of Nile tilapia (Oreochromis niloticus). Samplers were manufactured with nylon net, using substrates such as crushed stone, gravel, loofah and cattail leaves. Samples were collected after 30 days of colonization, rinsed and then the specimens were identified and quantified. The following metrics were calculated: richness of Operational Taxonomic Units, Margalef richness, abundance of individuals, Shannon index and evenness index. The macrobenthic community structure was strongly modified according to the proximity of the net cages. Metrics showed significant differences (p < 0.05) between near and distant sites, for both periods (dry and rainy seasons). The position of the samplers significantly affected the structure of macroinvertebrate community, as near sites showed higher values for the community metrics, such as richness and diversity. Near sites presented a larger number of individuals, observed both in the dry and rainy seasons, with a predominance of Chironomidae (Diptera) in the dry season and Tubificidae (Oligochaeta) in the rainy season.

Understanding the processes and mechanisms that underlie the spatiotemporal patterns of biodiversity is of paramount relevance, given the ongoing global climate and land cover changes. Here, we investigated the influence of season‐related climatic variables on two dimensions of dung beetle diversity (taxonomic and functional) and at different scales (alpha and beta) within an introduced Brazilian pasture ecosystem. We sampled dung beetles over 52 consecutive weeks, comprising the dry and rainy seasons. We related taxonomic and functional variables to season‐related climate variables (temperature, precipitation and humidity) using absolute values and changes from consecutive samplings (Δ, differences between samplings). We found higher species richness and abundance values in the rainy season. Changes in climatic variables between consecutive samplings caused effects only in functional dispersion, temporal β‐diversity and species losses but not in species richness and abundance of dung beetles. However, these effects are dependent on the season. In the rainy season, increased precipitation between samplings caused a decrease in functional dispersion and an opposite pattern was found in the dry season. Similarly, increased temperature values between samplings caused decreases in both temporal β‐diversity and species losses of dung beetles, with an opposite pattern in the dry season. Season‐associated climatic variables showed contrasting effects on dung beetle taxonomic and functional metrics. Temporal changes in taxonomic and functional diversity may be driven by different climatic variables, which can be associated with the sorting of species or species traits related to their thermal niche.

Herbicides such as glyphosate have been widely used in agriculture for several decades, and their occurrence in surface waters has been documented worldwide. However, information on the seasonal variability and occurrence of glyphosate in tropical coastal river systems remains limited, particularly in regions of the Gulf of Mexico. The present study aimed to quantify glyphosate concentrations in surface water from the Jamapa river (Veracruz, Mexico) during dry and rainy seasons and to evaluate their temporal variability and regulatory relevance. Three sampling campaigns were conducted in 2022 (May, June, and July), and glyphosate was analyzed using a competitive enzyme-linked immunosorbent assay (ELISA). Glyphosate was detected in all samples, with mean concentrations of 1.32µg L⁻1 in May (dry season), 0.15µg L⁻1 in June, and 3.7µg L⁻1 in July (rainy season), showing statistically significant seasonal differences (p < 0.05). Concentrations exceeded the European drinking water guideline (0.1µg L⁻1) but remained below Mexican and other international regulatory limits. These results provide baseline information on the occurrence and seasonal behavior of glyphosate in the Jamapa River and highlight the importance of continued monitoring of emerging contaminants in tropical river basins influenced by agricultural activities.

Los copépodos son el grupo más numeroso del zooplancton en los sistemas costeros tropicales; ellos se ven afectados principalmente por los gradientes de salinidad, como ocurre en el sector oriental del golfo de Cariaco. El propósito de este estudio fue estudiar las variaciones temporales y espaciales de la estructura de la comunidad de copépodos durante junio, julio, agosto y septiembre de 2009 (época de lluvia) y octubre, noviembre y diciembre de 2009 y enero de 2010 (época de sequía). Las muestras se recolectaron con una red estándar de zooplancton de 60 cm de diámetro con una malla de 330 μm a nivel superficial. La temperatura, salinidad y oxígeno disuelto se tomaron in situ con una sonda multiparamétrica (YSI). La salinidad presentó una marcada variabilidad mensual, con valores entre 32,5 ± 1,56 y 38,5 ± 0.25 UPS en las épocas de lluvia y sequía, respectivamente. Se identificó un total de 45 taxones de copépodos y Acartia tonsa fue la especie más representativa durante todo el estudio, seguido por Temora turbinata, Paracalanus quasimodo, Subeucalanus subcrassus y S. subtenuis. El presente estudio no mostró un claro patrón estacional en la abundancia, diversidad y la uniformidad de la comunidad de copépodos y los valores de salinidad; por lo tanto, puede considerarse espacialmente uniforme y estacionalmente homogéneo en relación a estos parámetros.

The maintenance of limnological monitoring programs in the Cerrado Domain is crucial as a provision of useful information about temporal variations in land use and their respective water quality responses, considering its importance as water source for different Brazilian hydrographic basins. The purpose of this research was to describe limnological variables of low-order lotic systems located in the Cerrado Long Term Ecological Research (LTER) site (Environmental Protection Area (APA) Gama and Cabeça de Veado, Federal District of Brazil). Altogether, nine different streams were considered in this study. Samplings were conducted between 2010 and 2012, concentrated in the dry and rainy seasons. The sampling sites were generally characterized by low nutrient concentrations (e.g., medians, TP = 14.8μgL(-1), TN = 20.0μgL(-1), NO3 = 13.8μgL(-1)) and slightly acidic waters (median, pH = 5.3), with quite low electrical conductivity values (median = 6.4μScm(-1)). However, water quality degradation as a response to diffuse pollution was reported in some sampling points (e.g., Onça and Gama streams), expressed by relatively higher N and P concentrations, which were probably highlighted by the good water quality of the data set as whole. Although there was a trend to higher values of nitrogen forms during the dry season, significant statistical differences between the seasonal periods were reported only for the variables temperature and dissolved silica, which were higher in the dry and rainy season, respectively. The streams located in the preserved areas inside the ecological stations of APA Gama and Cabeça de Veado can still be considered good examples of reference lotic systems in the Cerrado Domain; notwithstanding, this study reported incipient signs of water quality degradation which cannot be overlooked in future limnological monitoring.

Background: The physiochemical parameters of a river tell much about its quality and suitability for both humans and thesurvival of the living biota within it. The discharge of untreated wastewater into the surface water bodies such as streams andrivers results in the pollution of such water environments. We aimed to determine the physicochemical parameters and alsodetermine the seasonal variation of the physicochemical parameters river Kaduna.Methodology: The research was carried out within four areas in Kaduna North, Kaduna state, Nigeria. Selected sampling sitesinclude; Gamji Park, Kabala Costain, Malali and Unguwar Rimi. Monthly sampling of the four sites was carried out from eachsampling site for a period of eight months covering both the dry and the rainy season between 6:00 am and 8:00 am every sampling day. The following parameters were determined using standard laboratory techniques; temperature, pH, turbidity, totaldissolved solids, electrical conductivity, dissolved oxygen, biological oxygen demand, water hardness, nitrate-nitrogen andphosphate-phosphorus. Data was analyzed using simple descriptive statistics to calculate the mean, standard error (SE) andstandard deviation of the parameters.Results: The mean water temperature was 23.6±0.90C with a standard deviation of 2.5, the highest temperature (25.7±0.60C)was recorded in the wet season. Mean pH was 7.9±0.1 with a standard deviation of 0.4, the wet and the dry season had the samemean values of 7.9±0.1. The mean turbidity was 60.3±4.6 with a standard deviation of 12.8, the wet season had the highest value(72.5±2.4 NTU). Mean TDS was 72.1±13.9 with a standard deviation of 38.9 and the highest TDS value of 92.7±22.9 mg/L was recorded in the dry season. The mean values of electrical conductivity, dissolved oxygen and biological oxygen demand was135±27.7µs/cm, 2.6±0.1mg/L and1.3±0.1mg/L respectively whereas water hardness, nitrate-nitrogen and phosphate-phosphorushad means of 143.5±13.0 mg(CaCO3L-1, 0.3±0.0mg/L and 0.1±0.1mg/L respectively.Conclusion: physicochemical parameters were determined to be within the permissible level and wide seasonal variations wereseen among some parameters.

Protecting China's rivers

Aim: This study compared the leaf breakdown of Eucalyptus grandis Hill ex. Maiden (an exotic species) and Hyrtella glandulosa Spreng. (a native species), in order to assess the role of invertebrates in decomposition in two tropical lakes (Aguape and Barra) of the Rio Doce State Park in Southeast Brazil, receiving allochthonous organic matter during the dry and rainy seasons; Methods: Senescent leaves (4 ± 0.1 g dry weight) were placed in litter bags (30 × 30 cm, 5 mm mesh size) and submerged in the lakes. Replicate bags (n = 4) were then retrieved after 3, 7, 15, 30, 60, 90 and 120 days; Results: The breakdown of E. grandis leaves (range k = –0.007 to –0.015) was faster than H. glandulosa (range k = –0.005 to –0.008). Breakdown rates were higher during the rainy season than the dry season. Leaves of E. grandis and H. glandulosa did not differ in terms of invertebrate colonization. The highest densities were observed in Aguape Lake during the rainy season. Taxonomic richness was higher in E. grandis and in Aguape Lake, but no differences between the rainy and dry seasons were observed. Functional trophic groups differed between leaf types and seasons. Gatherer-collectors and scrapers predominated in E. grandis and in the dry season; Conclusions: The higher breakdown observed in Barra Lake was probably a consequence of the elevated temperatures and the presence of Gastropoda (scrapers). Aquatic invertebrates did not have difficulties in the colonization of exotic leaves (E. grandis) compared with native leaves (H. glandulosa). We observed that in the rainy season, the higher decay rates and density of invertebrate communities, indicating the increased temperatures, nutrient inflow and organic matter brought by the rain, accelerated this process compared with the dry season.

From water to edible fish. Transfer of metals and metalloids in the San Roque Reservoir (Córdoba, Argentina). Implications associated with fish consumption

The degradation of water quality has become a major problem today. In Indonesia, the decline in water quality is caused by domestic wastewater which is a non-point source. In an effort to reduce the occurrence of environmental degradation due to domestic wastewater, it is necessary to give an idea and convince the public and the relevant parties of the importance of domestic wastewater management. Efforts are made by informing the pattern of distribution of domestic wastewater in a region and the impact of its distribution for its control and management. The research method uses a momentary sampling technique in accordance with SNI 6989.59:2008. The location of the water sampling is determined purposively. Sampling was conducted in two periods; the dry season in September and the rainy season in January. The observed parameters included BOD5 and E.coli. Determination of the distribution of domestic wastewater uses GIS. The distribution of domestic wastewater is determined based on pollution levels expressed as IP. The results show that pollution levels in Sawojajar and Sumbersari were lightly polluted with average IPs of 4.09 and 4.02 (dry season). While Kedungkandang is in the good category, IP = 0.32 (dry season).

Wastewater reuse is now widely recognised as an important source of water supply in water-scarce countries and a solution to environmental problems associated with untreated wastewater discharge. In the Eastern Caribbean, competition for potable water between tourism and local domestic needs has seen a growth of desalination treatment plants. The need for water by the tourism sector peaks during the dry season when availability is at its minimum. While desalination has been utilised to meet growing demands, hotels and resorts are now required, in many cases, to treat wastewater to a high standard to meet environmental standards so that the coastal areas, on which these hotels and resorts depend, are protected. This paper discusses the potential of wastewater reuse in the main tourism-dependent islands in the Eastern Caribbean. The nexus between desalination and wastewater reuse allows the hotels and resorts sector to reduce the overall costs of water supply, overcome shortages in the dry season and meet stringent wastewater disposal requirements, as it was found that wastewater reuse can meet up to 38% of total needs. In many of the islands, there are suitable conditions for promoting wastewater reuse.