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In Chile, salt (NaCl) use per salmon fish farm ranges between 20-30 t yr(-1) and is used to prevent and control fungal infections. An increase in salinity in freshwater can have adverse effects on freshwater biodiversity and ecosystem functions and services. We studied the effects of fish-farm effluents on benthic macroinvertebrate communities in a northern Patagonian stream (Chile). Benthic samples were collected at 3 sites near a land-based salmon aquaculture facility (one located 100 m upstream from the fish-farm outlet for effluent, 2 sites located 200 and 400 m downstream from the effluent source). We found changes in benthic macroinvertebrate communities downstream from the effluent, with higher abundances of tolerant taxa and lower abundances of sensitive taxa, which was related to nutrient and salt concentration in the water. We also studied the effects of salinity on macroinvertebrate drift in a mesocosm experiment conducted in recirculating channels, measuring the drift of 2 salt-sensitive macroinvertebrates (Andesiops peruvianus and Smicridea annulicornis), collected from an unpolluted northern Patagonian stream, after exposure to a range of salinity concentration pulses similar to those from fish farms. Our results demonstrate that (1) fish-farm effluent can alter stream macroinvertebrate community composition and dynamics, and (2) such effects are at least partly driven by high salt concentrations in effluent waters. We thank the vice rectory for research and postgraduate studies at the Catholic University of Temuco and project MECESUP UCT 0804. The study was funded by the Fondecyt project 'Tracing organic pollution from land-based aquaculture systems in terms of fluorescence spectroscopy and assessment of ecotoxicological biomarkers in aquatic organisms in Southern Chile' (Ref. 1130132). L.B. was supported by the Spanish Ministry for Science, Innovation and Universities funds (Ref. RTI2018095023-B-I00) and Basque Government funds (Ref. IT95116) to the UPV/EHU Stream Ecology Group. Editorial

The distribution, composition, and transport of both dissolved and particulate organic carbon (DOC and POC) were studied across a terrestrial - marine transition system in the Chilean North-Patagonia (41°S). At the land-fjord boundary we reported: (i) high concentrations of both silicic acid (up to 100 μM) and integrated chlorophyll a (62 mg m−2), (ii) dominance of nanophytoplankton (63%), humic-, terrigenous-derived, and protein-like DOC (19 and 36%, respectively), and (iii) a shallow photic zone (12 m depth). In contrast, the estuarine-ocean boundary was characterized by (i) high concentrations of nitrate and phosphate (20 and 2 μM respectively) and low chlorophyll a concentration (11 mg m−2), (ii) dominance of microphytoplankton (59%) and tyrosine-like C3 autochthonous DOC (34%), and (iii) a deep photic zone (29 m depth). Allochthonous DOC input at the fjord head and the ocean accounted for 60% and 10% of total DOC, respectively. The input of humic-like substances was enhanced by intense forestry and agriculture activity around the Puelo River watershed, contributing from 50% to 14% of total DOC along the fjord - ocean transect. In contrast, autochthonous tyrosine-like substances increased from 25% to 41% of total DOC, highlighting the role of bacterial metabolism in regulating DOM composition. The high correlation (R2 = 0.7) between the UVC-humic:UVA-humic ratio and salinity suggest that processes associated to freshwater input impinged on the DOC chemical characteristics and origins. Overall, our observations support the view that climate warming (freshwater input) and anthropogenic practices (aquaculture) boost the mobilization of terrestrial carbon pools and their intrusion into coastal ocean areas, a process that should be given more attention in climate prediction models.

In this study, the occurrence and diffusive air-water exchange of POPs in Panguipulli Lake (39°42'S-72°13'W), an oligotrophic lake located in northern Patagonia (Chile), were determined. Air and water samples were collected between March and August 2017 (autumn-winter) and analyzed for concentrations of OCPs (α-HCH, β-HCH, γ-HCH and HCB) and PCBs (PCB-28,-52,-101,-118,-153,-158,-180) using gas chromatography coupled with an electron capture detector. The direction of air-water exchange direction was evaluated using a fugacity approach (ƒw ƒa-1), and net diffusive exchange fluxes (FAW, ng m-2 d-1) were also estimated. Total ∑4OCP levels in air ranged from 0.31 to 37 pg m-3, with a maximum for β-HCH, while Σ7PCB levels ranged from 3.05 to 43 pg m-3. The most abundant congener was PCB-153, accounting for 60% of the total PCBs in air. Surface water ∑4OCPs measured in this study ranged from 1.01 to 3.9 pg L-1, with γ-HCH predominating, while surface water Σ7PCB levels ranged from 0.32 to 24 pg L-1, with PCB-101, PCB-118, and PCB-153 presenting the highest levels. Diffusive air-water exchanges of HCB, α-HCH, γ-HCH and PCBs in the form of volatilization from the lake to air predominated; in contrast, for β-HCH net deposition dominated during the sampling period. Estimates suggested faster microbial degradation in the dissolved phase compared to atmospheric degradation for all analyzed POPs. Overall, these results could indicate that the oligotrophic lakes of northern Patagonia act as a secondary source of atmospheric POPs, mainly PCBs and some OCPs. This study is a first attempt to understand the occurrence of POPs in air and water, as well as their dynamics in oligotrophic lakes in the southern hemisphere., This study was funded by ANID/FONDECYT/Iniciación 11150548, ANID/FONDECYT/Regular 1161504, ANID/FONDECYT/Regular 1210946, ANID/PCI REDI170292, ANID PIA INACH ACT192057, INACH REGULAR RT_12_17 (C. Galbán-Malagón) and ANID/FONDECYT/Postdoctorado Nº3180159 (F. Tucca). Additionally, the authors acknowledge the support of the ANID/FONDAP/CRHIAM/15130015 and ANID/FONDECYT/1161673 projects (R. Barra). The authors are grateful for the logistical help of the Universidad Austral de Chile in the collection of water and air samples at Panguipulli Lake.

The global aquaculture industry has grown exponentially in recent years using to control of infections and diseases, a variety of veterinary drugs (VMP) are used, including antibiotics, antifungals and antiparasitics, which have different routes of emission, environmental persistence and side effects to aquatic organisms, becoming one of the main concerns in its use of veterinary drugs (VMP) and its potential toxicological impact on the environment, in this context, Chile is considered one of the main salmon producers. Ecological risk assessment of active principles used infreshwater fish farms worldwide and in Chile were investigated. We recollect a physical - chemical properties of active principles used by fish farms and we could estimate the relative hazard a priori. Later active principles grouped as antibiotics (n = 6), antiparasitics (n = 5), anesthetics (n = 3), and disinfectants (n = 7) were assessed using a mass balance model based on fugacity was developed for each active principle under treatments via immersion and food administration in fish, while a volumetric model for disinfectants and sodium chloride was used for estimating the predicted environmental concentration (PEC), under a real smolt farming scenario in fish farms. Ecotoxicological data were collected from open literature to predict the no-effect concentration (PNEC). The ecological risk assessment was characterized using a risk quotient (RQ = PEC/PNEC) based in two assessment tiers. Results revealed that 12 active ingredients showed a high risk (RQ ≥ 1), thus indicating that adverse effects could occur and further investigation with measured concentrations in the field are required to reduce exposure in surface waters.

Streamside native forests are known for their key role in water provision, commonly referred to as buffers that control the input or output of nutrients from terrestrial to aquatic ecosystems (i.e., nitrogen or carbon cycle). In order to assess the functional role of indigenous forests along streamside channels, we measured 10 parameters associated with DOM (Dissolved Organic Matter) at 42 points in 12 small catchments (15&ndash, 200 ha) dominated by native forests (reference, WNF), forest plantations (WFP) and agricultural lands (WAL) in which the land cover portion was calculated in the entire watershed and along 30 and 60-m wide buffer strips. We found that watersheds WFP and WAL were statistically different than WNF, according to DIC concentrations (Dissolved Inorganic Carbon) and the intensity of the maximum fluorescence of DOM components. Using linear models, we related streamside native forest coverage in buffer strips with DOM parameters. The increase of streamside native forest coverage in 60 m wide buffer strips (0&ndash, 100%) was related to lower DIC concentrations (0.89 to 0.28 mg C L&minus, 1). In watersheds WFP and WAL, the humic and fulvic-like components (0.42 to 1.42 R.U./mg C L&minus, 1) that predominated were related to an increase in streamside native forest coverage in the form of a 60 m wide buffer strip (0&ndash, 75%). This is evidence that streamside native forests influence outputs of detritus and lowered in-stream processing with concomitant downstream transport, and functional integrity and water quality. We propose that DOM quantity and quality may be a potential tool for the identification of priority areas near streams for conservation and ecological restoration in terms of recovery of water quality as an important ecosystem service. The results of this study are useful to inform policy and regulations about the width of streamside native forests as well as their characteristics and restrictions.

Protected areas (PAs) are critically important means to preserve species and maintain natural ecosystems. However, the potential impacts of chemical pollution on PAs are seldom mentioned in the scientific literature. Research on the extent of the occurrence of chemical pollution inside PAs and in-depth assessments of how chemical contaminants may adversely affect the maintenance of species abundance, species survival, and ecosystem functions are scarce to nonexistent. We investigated 1) the occurrence of chemical contaminants inside 119 PAs in Latin America from publically available databases, and 2) reviewed case studies of chemical contaminants and pollution in 4 Latin American PAs. Cases of chemical pollution and contamination inside Latin American PAs mostly originated from sources such as mining, oil, and gas extraction. To date, the focus of the research on chemical pollution research inside Latin American PAs has been primarily on the detection of contamination, typically limited to trace metals. Where management actions have occurred, they have been reactive rather than proactive. Protected areas established in wetlands are the most affected by chemical pollution. Based on the information from the pollution and/or contamination occurrence and the case studies analyzed, Latin American PAs are not well safeguarded from chemical pollution, resulting in both challenges and opportunities to conserve biodiversity and ecosystems. Integr Environ Assess Manag 2017;13:360-370. © 2016 SETAC.

Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17–9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

Polycyclic aromatic hydrocarbons (PAHs) are semivolatile organic compounds of environmental concern. This study aims to investigate the influence of local sources of anthropogenic PAHs and their air–water exchange fluxes in an oligotrophic North–Patagonian lake in Chile. The monitoring was carried out in Panguipulli Lake during a six-month period during the autumn and winter seasons (March to August 2017) using a high–volume air sampler and a pump system for water samples. We detected and quantified fifteen PAHs in the gas phase (mean ∑PAHs = 11.6 ng m) and dissolved water phase (mean ∑PAHs = 961.8 pg L). Methylphenanthrenes and pyrene dominated the concentrations of PAHs in the studied phases. To determine sources of PAHs we used the PAH ratios of Light Molecular Weight/Heavy Molecular Weight (∑LMW/∑HMW) and Phenanthrene/Anthracene (Phe/Ant). The PAH ratio results revealed a pyrogenic source. We estimated the air–water diffusive exchange fluxes and fugacity ratios for the studied compounds. In general, air–water diffusive exchanges of PAHs showed a net volatilization for the less hydrophobic (log K < 4) and lighter PAHs (MW ≤ 170 g mol), and a net deposition trend for the more hydrophobic (log K 4–7) and higher molecular weight PAHs (MW ≥ 178 g mol). We found a significant correlation between log water/air fugacity ratios and log K of PAHs. Therefore, it is suggested that this oligotrophic lake acts as a sink by accumulating hydrophobic and mid-high molecular weight PAHs derived mainly from pyrogenic sources. This study is the first attempt to understand the sources and behavior of PAHs in oligotrophic lakes in the Southern Chile where information is scarce regarding the occurrence of PAHs., This study was funded by ANID FONDECYT 11150548, 1161504, ANID PCI REDI170292, ANID PIA Anillo INACH ACT192057, INACH REGULAR RT_12_17 (C. Galbán-Malagón) and ANID FONDECYT N° 3180159 (F. Tucca). Authors also thank the support of ANID FONDAP CRHIAM 15130015 (R. Barra and F. Tucca), ANID FONDECYT 1161673 (K. Pozo), “Universidad Andrés Bello” is thanked for funding a PhD scholarship awarded to Miss Thais Luarte. The “Universidad Austral de Chile” was highly acknowledged by their continuous logistic support on the lake. Kevin Ryan PhD(c) is thanked for language editing of the final version of the present manuscript.

The suitability of Mazzaella laminarioides and Sarcothalia crispata as heavy metal biomonitors of Cd, Cu, Hg, Pb, and Zn was assessed by comparing bioaccumulation of these elements in different life stages and frond sizes in samples from three locations, San Vicente Bay (industrial area), Coliumo, and Quidico (the latter as a reference station), where different degrees of heavy metal pollution are recorded. Bioaccumulation and bioconcentration factors of Cd, Cu, Hg, Pb, and Zn were evaluated. The two macroalgae species showed similar patterns, with higher values of Cu, Hg, Pb, and Zn in polluted areas. M. laminarioides bioaccumulated higher concentrations of all metals assessed than S. crispata, independent of life stage and frond size. The results also showed significantly higher Cu, Hg, Pb, and Zn concentrations (p

Aquacultures are of great economic importance worldwide but pollute pristine headwater streams, lakes, and estuaries. However, there are no in-depth studies of the consequences of aquacultures on dissolved organic matter (DOM) composition and structure. We performed a detailed molecular level characterization of aquaculture DOM quality and its bacterial degradation using four salmon aquacultures in Chile. Fluorescence measurements, ultrahigh-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy of the DOM revealed specific and extensive molecular alterations caused by aquacultures. Aquacultures released large quantities of readily bioavailable metabolites (primarily carbohydrates and peptides/proteins, and lipids), causing the organic matter downstream of all the investigated aquacultures to deviate strongly from the highly processed, polydisperse and molecularly heterogeneous DOM found in pristine rivers. However, the upstream individual catchment DOM signatures remained distinguishable at the downstream sites. The benthic algal biovolume decreased and the bacterial biovolume and production increased downstream of the aquacultures, shifting stream ecosystems to a more heterotrophic state and thus impairing the ecosystem health. The bacterial DOM degradation rates explain the attenuation of aquaculture DOM within the subsequent stream reaches. This knowledge may aid the development of improved waste processing facilities and may help to define emission thresholds to protect sensitive stream ecosystems.

International audience; Cyanobacterial blooms can be harmful to environmental and human health due to the production of toxic secondary metabolites, known as cyanotoxins. Microcystins (MCs), one of the most widespread class of cyanotoxins in freshwater, have been found to be positively correlated with cyanobacterial biomass as well as with nitrogen and phosphorus concentrations in temperate lakes. However, in tropical water bodies,cyanobacterial density and cyanotoxin correlation to environmental factors is not fully understood. In the present study, we examined the effects of total nitrogen and total phosphorus (TP) concentrations among other environmental parameters on cyanobacterial community structure and MC concentrations in the Dau Tieng reservoir, a tropical, eutrophic water body in Southern Vietnam. Cyanobacterial biomass and MC content were monitored monthly from March 2012 to February 2013, when MCs were present in the Dau Tieng Reservoir. The highest concentrations of intracellular MCs were found in September and February when cyanobacteria biomass reached maximum values, with 2.50 and 2.13 mg MC.L–1, respectively. Principle component analysis and redundancy analysis showed that MC concentration was positively correlated with the biomass of the cyanobacterial order Chroococcales, whereas TP was the primary abiotic factor influencing cyanobacterial biomass and MC concentrations in the Dau Tieng Reservoir. In addition, Bayesian model average analysis was used to construct a prediction model of MCs using cyanobacterial biomass and environmental variables revealing a suite of useful predictive factors for MCs in the Dau Tieng Reservoir, includingwater temperature, TP and the biomass of Chroococcales.

International audience; Seven strains of cyanobacteria from Tri An Reservoir, a drinking water reservoir for millions of people in Southern Vietnam, were isolated, cultivated, identified and described. They originated from the species Microcystis aeruginosa, M. botrys, M. wesenbergii, Anabaena circinalis,A. smithii, Aphanizomenon aphanizomenoides and Cylindrospermopsis raciborskii. Microcystin (MC) content in the cultures and two scum samples from Tri An Reservoir were determined by high performance liquid chromatography. Four variants of MC, MC-LR, MC-RR, MC-LA, MC-LY and one un-determined variant were detected in the scum samples but none were found in the cultures. The two variants MC-LA and MC-LY were recorded for the first time for Vietnam. Total MC concentrations in the two scum samples were 0.45 and 0.64 mg g-1 dried weight, respectively. The genus Microcystis in Tri An Reservoir was assumed to be a MC producer as the other possible MC producing species A. circinalis was usually detected in lower quantities.

International audience; Freshwater mussels such as the invasive Dreissena polymorpha and the indigenous Unio tumidus nourish by high filtration rates and may accumulate cyanobacteria and their toxins during cyanobacterial blooms. Physiological adaptations to cyanotoxins enable organisms to endure cyanobacteria lblooms but may differ between species. Biotransformation and excretion capacities for cyanobacteria and anthropogenic pollutants have been demonstrated for Dreissena polymorpha but less for unionid species. This study compares the activities of biotransformation (glutathioneS-transferase, GST) and antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) in Dreissena polymorpha to Unio tumidus in response to cyanotoxin exposure (10 mg L 1 and 50 mg L 1 microcystin-LR, respectively, total microcystin from a cyanobacterial crude extract) for 24h and 7 d exposure duration. Enzyme activities in Dreissena polymorpha were measured in the whole mussel tissue, digestive gland and in gills and in Unio tumidus in the digestive gland, gills, mantle, foot as well as in the remaining tissue. The sGST was elevated for the entire exposure period in the whole mussel tissue of Dreissena polymorpha but despite higher basal activities in digestive gland and gills of Unio tumidus, it was rather inhibited or unaltered in most of their tissues. Elevated SOD activity indicated oxidative stress response in Dreissena polymorpha, but not in Unio tumidus. The CAT activity was barely affected in both species, rather inhibited in Unio tumidus, despite again higher basal activities in digestive gland and remaining tissue. Compared to the indigenous Unio tumidus, the investigated biotransformation and oxidative stress combating enzymes respond stronger in the invasive Dreissena polymorpha.

Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM composition change and DON concentration increase differed among climate zones and could be related to the intensity of current and historical nitrogen fertilizer use. As a result of agriculture intensification, increased DON concentrations and a more microbial-like DOM composition likely will enhance the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks and resulting in higher ecosystem productivity and CO2 outgassing.