Physiological response measures (respiration, clearance, byssus production, survival) of Perna viridis during a 91 day exposure experiment to microplastics in Bogor, Indonesia, 2014

Perna viridis from the Bay of Jakarta was exposed to different concentrations (0, 21.6, 216 and 2160 mg/l) of PVC microplastic particles for 91 days in a controlled laboratory experiment. Particles were negatively buoyant, but were regularly resuspended from the sediment, mimicking tidal events. The particles were contaminated with the organic pollutant fluoranthene, except for one control group, which was exposed to the highest plastic concentration (2160 mg/l) but with clean particles. Within the 91 days survival was monitored. After 40 - 44 days of the exposure, physiological responses of all mussel individuals were measured. Respiration rates were measured as the decrease of oxygen in a sealed container in 20 minutes. Clearance rates were determined by measuring the depletion of algal cells in the water in 30 minutes. Byssus production was assessed by counting the number of newly formed byssus discs within 24 hours.

Avaliação da compactação do solo no crescimento inicial de espécies florestais da caatinga

Despite the importance of the study of roots, little is known about the negative effects of soil compaction in the development of the Caatinga forest species. In this sense, the objective was to evaluate the initial growth of Mimosa caesalpiniifolia, Tabebuia caraiba and Erythina velutina in soil under varying levels of compression. The experiment was conducted in a greenhouse located at the Academic Unit Specialized in Agricultural Sciences, UFRN. To perform the experiment, was used Oxisoil of sandy loam texture, from forest trial Area Agricultural School of Jundiaí (EAJ) of the municipality of Macaíba-RN, in an experimental unit consisting of three overlapping PVC rings, 10 cm in diameter and 25 cm in height, with a central ring which has undergone compression. The experimental design was a randomized block with six replications, being tested four levels of soil compaction (1.35; 1.45; 1.60 and 1.80 kg.dm-³), evaluating the following variables: diameter, height, number of leaves, dry weight of shoot and root system in each layer of the vessels. Overall, the species M. caesalpiniifolia, T. caraiba and E. velutina had initial growth favored by treatment consists of uncompressed soil. The M. caesalpiniifolia and T. caraiba species proved relatively resistant to compaction of the soil does not undergo any significant reduction in root growth density equal to or less than 1.60 kg.dm-³, whereas E. velutina proved susceptible effects of soil compaction, with significant changes in root growth under soil densities equal to or greater than 1.45 kg.dm-³. Increased soil compaction caused the impediment to the expansion of taproot inside the experimental units, promoting the accumulation of roots in the upper layers of the soil for the studied species. The subsoil physical impediment changed the initial aerial growth of M. caesalpiniifolia and E. velutina, but did not influence the growth of air T. caraiba seedlings the tested compression levels.

Estudo da redução de arrasto induzido por polímeros em escoamentos internos turbulentos em dutos

The flows turbulent and laminar are present in various applications of engineering and one of the villain of energy loss big is the surface friction. Currently, there are several research aimed for the study of reducing drag (DR) with the objective of developing effective methods to reduce the friction. Regardless of numerous research carried out until today, the phenomenon DR still remains in study not it is fully understood. This paper studied the drag reduction by polymer induction in turbulent internal flows in ducts. We constructed a testing bench to perform the analysis of drag reduction, the bench has basically two manometers with a 8.5 psi full scale, a peripheral pump 0.5 HP, an acrylic tank, valves and tubes pvc and is situated in the Laboratory Fluid Mechanics UFRN. Were used as polymer additives to polyethylene glycol 4000, the Polyox WSR N60K, Polyox WSR 301 and Polyox WSR 205. The rationale for the choice of these polymers is their wide application in situations requiring greater energy efficiency, such as the addition reducing polymers for the jet used by the fire department to achieve greater distances. The induced drag reduction polymers is investigated from the turbulent flow analysis, with Reynolds number in a range between 2×104

Estudo da redução de arrasto induzido por polímeros em escoamentos internos turbulentos em dutos

The flows turbulent and laminar are present in various applications of engineering and one of the villain of energy loss big is the surface friction. Currently, there are several research aimed for the study of reducing drag (DR) with the objective of developing effective methods to reduce the friction. Regardless of numerous research carried out until today, the phenomenon DR still remains in study not it is fully understood. This paper studied the drag reduction by polymer induction in turbulent internal flows in ducts. We constructed a testing bench to perform the analysis of drag reduction, the bench has basically two manometers with a 8.5 psi full scale, a peripheral pump 0.5 HP, an acrylic tank, valves and tubes pvc and is situated in the Laboratory Fluid Mechanics UFRN. Were used as polymer additives to polyethylene glycol 4000, the Polyox WSR N60K, Polyox WSR 301 and Polyox WSR 205. The rationale for the choice of these polymers is their wide application in situations requiring greater energy efficiency, such as the addition reducing polymers for the jet used by the fire department to achieve greater distances. The induced drag reduction polymers is investigated from the turbulent flow analysis, with Reynolds number in a range between 2×104

Remote Sensing of Vegetation Change Across a Latitudinal Gradient in the Canadian Arctic

Global air surface temperatures and precipitation have increased over the last several decades resulting in a trend of greening across the Circumpolar Arctic. The spatial variability of warming and the inherent effects on plant communities has not proven to be uniform or homogeneous on global or local scales. We can apply remote sensing vegetation indices such as the Normalized Difference Vegetation Index (NDVI) to map and monitor vegetation change (e.g., phenology, greening, percent cover, and biomass) over time. It is important to document how Arctic vegetation is changing, as it will have large implications related to global carbon and surface energy budgets. The research reported here examined vegetation greening across different spatial and temporal scales at two disparate Arctic sites: Apex River Watershed (ARW), Baffin Island, and Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, NU. To characterize the vegetation in the ARW, high spatial resolution WorldView-2 data were processed to create a supervised land-cover classification and model percent vegetation cover (PVC) (a similar process had been completed in a previous study for the CBAWO). Meanwhile, NDVI data spanning the past 30 years were derived from intermediate resolution Landsat data at the two Arctic sites. The land-cover classifications at both sites were used to examine the Landsat NDVI time series by vegetation class. Climate variables (i.e., temperature, precipitation and growing season length (GSL) were examined to explore the potential relationships of NDVI to climate warming. PVC was successfully modeled using high resolution data in the ARW. PVC and plant communities appear to reside along a moisture and altitudinal gradient. The NDVI time series demonstrated an overall significant increase in greening at the CBAWO (High Arctic site), specifically in the dry and mesic vegetation type. However, similar overall greening was not observed for the ARW (Low Arctic site). The overall increase in NDVI at the CBAWO was attributed to a significant increase in July temperatures, precipitation and GSL.

Nonlinear soil-structure interaction for buried pressure pipes under differential ground motion

Pipelines extend thousands of kilometers across wide geographic areas as a network to provide essential services for modern life. It is inevitable that pipelines must pass through unfavorable ground conditions, which are susceptible to natural disasters. This thesis investigates the behaviour of buried pressure pipelines experiencing ground distortions induced by normal faulting. A recent large database of physical modelling observations on buried pipes of different stiffness relative to the surrounding soil subjected to normal faults provided a unique opportunity to calibrate numerical tools. Three-dimensional finite element models were developed to enable the complex soil-structure interaction phenomena to be further understood, especially on the subjects of gap formation beneath the pipe and the trench effect associated with the interaction between backfill and native soils. Benchmarked numerical tools were then used to perform parametric analysis regarding project geometry, backfill material, relative pipe-soil stiffness and pipe diameter. Seismic loading produces a soil displacement profile that can be expressed by isoil, the distance between the peak curvature and the point of contraflexure. A simplified design framework based on this length scale (i.e., the Kappa method) was developed, which features estimates of longitudinal bending moments of buried pipes using a characteristic length, ipipe, the distance from peak to zero curvature. Recent studies indicated that empirical soil springs that were calibrated against rigid pipes are not suitable for analyzing flexible pipes, since they lead to excessive conservatism (for design). A large-scale split-box normal fault simulator was therefore assembled to produce experimental data for flexible PVC pipe responses to a normal fault. Digital image correlation (DIC) was employed to analyze the soil displacement field, and both optical fibres and conventional strain gauges were used to measure pipe strains. A refinement to the Kappa method was introduced to enable the calculation of axial strains as a function of pipe elongation induced by flexure and an approximation of the longitudinal ground deformations. A closed-form Winkler solution of flexural response was also derived to account for the distributed normal fault pattern. Finally, these two analytical solutions were evaluated against the pipe responses observed in the large-scale laboratory tests.

Oil Flow Rate Measurements Using 198au And Total Count Technique

In industrial plants, oil and oil compounds are usually transported by closed pipelines with circular cross-section. The use of radiotracers in oil transport and processing industrial facilities allows calibrating flowmeters, measuring mean residence time in cracking columns, locate points of obstruction or leak in underground ducts, as well as investigating flow behavior or industrial processes such as in distillation towers. Inspection techniques using radiotracers are non-destructive, simple, economic and highly accurate. Among them, Total Count, which uses a small amount of radiotracer with known activity, is acknowledged as an absolute technique for flow rate measurement. A viscous fluid transport system, composed by four PVC pipelines with 13m length (12m horizontal and 1m vertical) and ½, ¾, 1 and 2-inch gauges, respectively, interconnected by maneuvering valves was designed and assembled in order to conduct the research. This system was used to simulate different flow conditions of petroleum compounds and for experimental studies of flow profile in the horizontal and upward directions. As 198Au presents a single photopeak (411,8 keV), it was the radioisotope chosen for oil labeling, in small amounts (6 ml) or around 200 kBq activity, and it was injected in the oil transport lines. A NaI scintillation detector 2”x 2”, with well-defined geometry, was used to measure total activity, determine the calibration factor F and, positioned after a homogenization distance and interconnected to a standardized electronic set of nuclear instrumentation modules (NIM), to detect the radioactive cloud.

Evaluation of Gaseous Fluid Dispersion Through Packed Bed Using Radiotracers Technique

In this study, it was developed a methodology for the determination of the dispersion of a gaseous tracer in porous media using the radiotracer technique. In order to evaluate several porous media, a cylindrical filter was constructed in PVC and connected to a system with constant flow. Inside this unit silica crystals (16-20) mesh was used as porous media and CH3Br (Methyl Bromide) marked with 82Br was used as radiotracer. An instantaneous pulse of tracer was applied in the system entrance and registered by two NaI (3x3)” scintillation detectors located one before and the other after the filter. The curves produced by the radioactive cloud and recorded by the detector were analyzed statistically using the weighted moment method. The mathematical model one considered as great dispersion of tracer was used to evaluate the flow conditions inside the filter system. The results show us that the weight moment method associated with radiotracer techniques is useful to evaluated an industrial filter and allows to measure the residence time distribution, τ, and the axial dispersion, DAB, gas in a porous medium.

Projeto e desenvolvimento de um sistema de irradiação multipropósito com diagnóstico de feixes para o acelerador de partículas cíclotron CV 28

O projeto e desenvolvimento de uma nova linha de feixe dotada de um sistema que viabilize a irradiação no Cíclotron CV-28 do Instituto de Engenharia Nuclear de alvos extensos e de geometria variável tornaram-se necessário para a realização de estudos e desenvolvimento de aplicações de técnicas nucleares e análises de materiais por ativação em condições de irradiação até então não disponíveis. Este sistema que poderá ser utilizado em irradiações com feixes de prótons, alfas, deutério e hélions (He3) a energias variáveis, é composto por dispositivos de: proteção, interceptação, colimação e medição da intensidade do feixe, de forma a possibilitar a realização de irradiações em condições controláveis e reprodutíveis. Para tanto, peças em alumínio e PVC-foram usinadas de forma a construir os componentes do sistema, notadamente colimadores com 13mm e 9mm de diâmetro, um dispositivo de colimação de quatro setores, um "beam stop", duas flanges de isolamento elétrico e um porta alvo (com janela degradadora). Identificou-se também a necessidade de se dotar o sistema aqui desenvolvido de um circuito de refrigeração próprio à água deionizada que é responsável pela refrigeração de todos os seus componentes que possam ter contato com o feixe. O sistema conta ainda com conexões para vácuo, que possibilitam fazer um pré-vácuo em sua câmara de irradiação, de forma que a mesma possa interligada a linha de transporte de feixe de Cíclotron CV-28, sem causar danos ao vácuo do mesmo. A condição para se fazer esta interligação é a obtenção de um pré-vácuo no ordem de 10-4 torr. Os resultados experimentais obtidos com a realização de irradiações de alvos metálicos especialmente desenvolvidos para testar o sistema, que é tema da presente dissertação, atestam a confiabilidade e reprodutibilidade das condições de irradiação, o que viabilizam o desenvolvimento e emprego de novas unidades de irradiação a serem incorporadas ao mesmo. Esse sistema de irradiação já está sendo utilizado na linha 2 do CV-28

Mécanisme de salissage et de nettoyage en surface de matériaux polymères

Résumé: Le développement de l’industrie des polymères fourni de plus en plus de choix pour la formulation de matériaux pour les couvre-planchers. Les caoutchoucs, le PVC et le linoleum sont les polymères habituellement utilisés dans l’industrie des couvre-planchers. Ce projet répond à un problème de facilité de nettoyage des couvre-planchers de caoutchouc qui sont reconnus pour être mous, collants et ayant une surface rugueuse. L’INTRODUCTION couvrira l’état actuel de la recherche sur les couvre-planchers, surtout en regard au problème de la «nettoyabilité». La théorie pertinente et les informations générales sur les polymères, les composites polymériques et la science des surfaces seront introduites au CHAPITRE 1. Ensuite, le CHAPITRE 2 couvrira la méthode utilisée pour déterminer la nettoyabilité, l’évaluation des résultats ainsi que l’équipement utilise. Le CHAPITRE 3, discutera des premières expériences sur l’effet de la mouillabilité, la rugosité et la dureté sur la facilité de nettoyage des polymères purs. Plusieurs polymères ayant des surfaces plus ou moins hydrophobes seront investigués afin d’observer leur effet sur la nettoyabilité. L’effet de la rugosité sur la nettoyabilité sera investigué en imprimant une rugosité définie lors du moulage des échantillons; l’influence de la dureté sera également étudiée. Ensuite, un modèle de salissage/nettoyage sera établi à partir de nos résultats et observations afin de rationaliser les facteurs, ou « règles », qui détrminent la facilité de nettoyage des surfaces. Finalement, la réticulation au peroxyde sera étudiée comme une méthode de modification des polymères dans le but d’améliorer leur nettoyabilité; un mécanisme découlant des résultats de ces études sera présenté. Le CHAPITRE 4 étendra cette recherche aux mélanges de polymères; ces derniers servent habituellement à optimiser la performance des polymères purs. Dans ce chapitre, les mêmes tests discutés dans le CHAPITRE 3 seront utilisés pour vérifier le modèle de nettoyabilité établi ci-haut. De plus, l’influence de la non-miscibilité des mélanges de polymères sera discutée du point de vue de la thermodynamique (DSC) et de la morphologie (MEB). L’utilisation de la réticulation par peroxyde sera étudié dans les mélanges EPDM/ (E-ran-MAA(Zn)-ran-BuMA) afin d’améliorer la compatibilité de ces polymères. Les effets du dosage en agent de réticulation et du temps de cuisson seront également examinés. Finalement, un compatibilisant pré-réticulé a été développé pour les mélanges ternaires EPDM/ (E-ran-MAA(Zn)-ran-BuMA)/ HSR; son effet sur la nettoyabilité et sur la morphologie du mélange sera exposé.

Measuring nitrous oxide emissions from conventional and controlled release fertilisers in south-east Queensland pineapple production

Nitrous oxide (N2O) is a potent greenhouse gas with a global warming potential 298 times higher than carbon dioxide. Soils are a natural source of N2O, contributing 65% of global emissions. This paper is the first in Australia to measure and compare N2O emissions from pre-plant controlled release (CR) and conventional granular (CV) fertilisers in pineapple production using static PVC chambers to capture N2O emissions. Farm 1 cumulative emissions from the CR fertiliser were 3.22 kg ha-1 compared to 6.09 kg ha-1 produced by the CV. At farm 2 the CV blend emitted 2.36 kg ha-1 in comparison to the CR blend of 2.92 kg ha-1. Daily N2O flux rates showed a relationship of direct response to rainfall and soil moisture availability. High emissions were observed for wheel tracks where increased N2O emissions may be linked to soil compaction and waterlogging that creates anaerobic conditions after rain events. Emission measurements over three months highlighted the inconsistencies found in other studies relative to reducing emissions through controlled release nitrogen. More investigations are required to verify the benefits associated with controlled release fertiliser use in pineapples, placement and seasonal timing to address N2O emissions in pineapples.

Reator de leito estruturado com recirculação submetido à aeração intermitente no tratamento de esgoto sanitário

The release of nitrogen compounds in water bodies can result in many environmental problems, so treat wastewater, such as sewage in order to remove not only organic matter but also nitrogen has been studied a few decades. From the above, the objective of this study was to evaluate the performance of a structured bed reactor, continuous flow, with recirculation, in removing organic matter and nitrogen present in wastewater under different cycles of intermittent aeration (AI) and to evaluate the influence of these cycles in the development of nitrifying bacteria (Oxidizing Bacteria Ammonia - BOA and Bacteria Oxidizing Nitrite - BON) and denitrifying (DESN) adhered (Support Material - MS) and suspension (Effluent - EF and sludge - LD). The reactor used has usable volume of 9.4 L. As support materials (MS) polyurethane foam was used, cut and fixed in PVC rods. 3 were worked aeration phases (AE) and non-aeration (AN) at different stage: Stage 1 (4 h EA / AN 2H); Stage 2 (2H EA / AN 1 h) and Phase 3 (2H EA / AN 2 h). During all hydraulic detention time phases was kept at 16 h and the effluent recirculated at a rate of 3 times the inflow. Were analyzed: pH, total alkalinity, temperature, chemical oxygen demand (COD), Biochemical Oxygen Demand (BOD), nitrogen Kjeldhl Total (NKT), ammonia-N-N-NH4+, nitrito-N-NO2+andnitrato-NO3-. The concentration of BOA, BON and DESN was determined using the number More Provável.gSSV-1 (NMP.gSSV-1). In phase 1 the percentage removal NTK N-NH4+ and NT was 76±10%, 70±21% and 67±10% respectively. In Phase 2 80±15% of removel NKT, 86±15% of N-NH4+ e 68±9% of removel NT e na Fase 3 de 58±20%, 72±28% and 41±6% of NKT, N-NH4+ of NT, respectively. The denitrification efficiency in stage 3 was over 70%, indicating that occurred in the reactor the process of simultaneous nitrification and denitrification (NDS). DQOT the removal percentages were 88 ± 4% in Phase 1, 94 ± 7 in Phase 2 and 90± 11% in Phase 3. The multivariate ANOVA applied to NMP.gSSV-1, it indicated that there was significant (F: 20,2, p <0,01) between the analyzed concentration of organisms AI in different cycles, but the differences between NMP.gSSV-1 depends not only isolated factors but of which means, and phase groups being analysis. From the results it is concluded that the working system is efficient in terms of nitrogen removal and organic matter, and that the stage with the highest availability of Dissolved Oxygen (DO) and C/N ratio (Step 2), was the one obtained the lower concentrations of organic matter effluents and N-NH4+. Hinted that there was a significant difference between the concentration (NMP.100mL-1) of the analyzed organizations (BOA, BON and DESN), but this difference does not depend on factors alone but of which means (MS, EF or LD), stages (1, 2 or 3) and groups (BOA, BON and DESN) is being considered.

Influência da profundidade e dos parâmetros ambientais sobre o desenvolvimento de Gracilaria birdiae (Rhodophyta, Gracilariales) em viveiro de camarão

This study evaluates the influence of depth and environmental parameters on the development of Gracilaria birdiae Plastino & Oliveira (Gracilariaceae Rhodophyta) in an organic shrimp pound (Litopenaeus vannamei) under euthrophical conditions. PVC structures (module) witch four ropes laden with 150 g of macroalgae each, were kept during 35 days at three different depths (surface, 10 and 20 cm depth). Wet biomass weighing and environmental parameters (temperature, salinity, turbidity, pH, transparence, precipitation, evaporation, insolation, accumulated solar radiation, nitrite, nitrate, ammonium and orthophosphate) were measured weekly. At all three proposed depths, the macroalgae displayed a higher biomass at the end of experiment than at the initial inoculations. The module kept at a 10 cm depth presented the greatest average biomass (186,3), followed by that kept at 20 cm (180,4 g) and the surface module (169,9 g). Biomass variations showed algae to suffer the direct effects of depths. Biomass loss was associated with the factors that influence light penetration, such as sediment deposits above the thallus, rate of evaporation and precipitation. The smallest loses occurred in the algae kept on surface (0,16%), followed by the algae kept at 20 cm (0,20%) and 10 cm (0,22%). The specific growth rate (SGR) of G. birdiae showed no significant difference between the three depths nor the sample periods. Nevertheless, the modules kept at 10 and 20 cm depths presented similar growth evolution, both growing 0,38%·per day-1, while the module kept on surface had an average SGR of 0,36%·day-1. The models related to growth rate demonstrated temperature, salinity, pH, orthophosphate, ammonium, precipitation and turbidity as the principal environmental parameters influencing the development of G. birdiae

Efeito dos nutrientes (nitrogênio e fósforo) sobre o desenvolvimento da Gracilaria birdiae: crescimento e possível uso como biofiltro

Marine shrimp farming has grown exponentially during the last years in Brazil. In spite of the promising economical situation, this activity is facing an increasing criticism due to its environmental impact. Thus, the necessity of alternatives to mitigate environmental degradation caused by this activity. An alternative that is being studied is the policulture that is the integrated culture of two or more organisms, normally one of them a filtering organism. Among filtering organisms, macroalgae are very practicable because they are efficient in the removal of the exceeding nutrients of the water and do not leave residues in the water. Besides, the integrated culture with macroalgae allows the economical exploration of the seaweed (for the manufacture of jelly and jam, for the dairy industry, pharmaceuticals, etc.) along with possibility of a sustainable aquaculture. In the present experiment, the development of the seaweed Gracilaria birdiae, the influence and tolerance of this species to the environmental parameters, and its absorption efficiency in relation with the three kinds of macronutrients (NH4+, NO3- and PO4-3) found in the effluents of marine shrimp farming was studied. The experiment was divided in two parts: a laboratorial part and one part carried under natural conditions. The water used in the laboratory trial was collected in the shrimp ponds of Tecnarão farm and distributed in aquaria containing 20 g of G. birdiae. In the field trial, 0.5 kg of G. birdiae was inserted in PVC cages cultivated in the farm. The results of the study showed a modest growth of G. birdiae, probably due to its low tolerance to highly eutrophicated environments. However, the removal of nutrients was very expressive. Ammonia was reduced in approximately 34 %. Ortho-phosphate showed a reduction of 93.5 %. The capacity of biofiltration of the NO3- by the macro algae was of 100 %, showing that G. birdiae is a seaweed-filtered with a high level of removal for this nutrient under laboratorial conditions. In spite of the low growth of the macro algae in the experiment, the results in relation to the removal of nutrients of the water was encouraging, suggesting that this species can be an efficient biofilter and thus, a strong candidate to be used in a sustainable aquaculture

Utilização da macroalga Ulva lactuca linnaeus na redução de nutrientes (NH4+,NO3- e PO4-2) provenientes da carcinicultura

Dentre as macroalgas capazes de absorver altas concentrações de N e P dissolvidos na água, destaca-se a Chlorophyta Ulva lactuca, bastante adaptável e resistente às adversidades ambientais, como grandes variações de temperatura, salinidade, matéria orgânica e metais pesados. Trata-se também de uma espécie bastante comum nas áreas intertidais do litoral norte-riograndense. Devido a suas características ecológicas, fisiológicas e nutricionais, foi avaliado nesse estudo, o seu potencial como biofiltro na redução de NH4+, NO3- e PO4-2, tanto em condições controladas como também em um viveiro de camarão. No experimento laboratorial, foram utilizados quatro aquários de vidro de 30 x 20 x 20cm com 10L de água, sendo três aquários experimentais contendo 20g de U. lactuca e um controle. O acréscimo de biomassa foi de 2,92g (22,92 ± 6,29g; p < 0,05) em relação ao inóculo inicial de 20g, sob temperatura (28,50 ± 0,58ºC), salinidade (35,00 ± 0,00 ), pH (8,26 ± 0,02) e luz constante (250 μmol.m2s-1). O crescimento positivo (1,78 ± 4,38%dia-1; p < 0,05), juntamente com a alta eficiência de absorção de amônio (83%; p < 0,001), nitrato (83%; p < 0,001) e ortofosfato (53%; p < 0,001), demonstrou que, nessas condições, a Ulva lactuca absorveu os nutrientes e aumentou sua biomassa. Já no experimento de campo, realizado na fazenda TECNARÃO, situada no município de Arez/RN (06° 11 40 Latitude Sul, e 35º 09 37 Longitude Oeste), foram utilizadas três gaiolas de PVC, posicionadas a 12cm da superfície da água, cada uma com dimensões de aproximadamente 59 x 59 x 15cm, onde foram colocadas 200g de U. lactuca. O ganho de biomassa de 3g (203,00 ± 41,02g; p < 0,001) foi muito semelhante às condições controladas, demonstrando a adaptabilidade da espécie em condições ambientais variáveis, onde, apesar da temperatura pouco variável (27,45 ± 0,64ºC), houve progressiva diminuição de salinidade (25 - 15 ), devido ao período de fortes chuvas (34,70 ± 23,78mm). Somado a isso, foram observados vários fatores biológicos interferindo no viveiro, como a presença de epífitas, organismos endofíticos, fouling e a herbivoria por parte dos próprios camarões. Houve aumento nas concentrações de NH4+ (4,36 ± 1,69 μmol.L-1), NO3- (0,17 ± 0,25μmol.L-1) e PO4-2 (0,41 ± 0,13μmol.L-1), coincidindo com o crescimento da espécie até a terceira semana. Todos os parâmetros ambientais analisados, assim como a biomassa e a Taxa de Crescimento Relativo (TCR), obtidos no campo, apresentaram variações altamente significativas (p < 0,001). As correlações observadas entre biomasa e NH4+ (r = 0,82; p < 0,001) e entre biomassa e PO4-2 (r = 0,87; p < 0,001), indicam que esta espécie é capaz de ter um crescimento satisfatório nas condições eutróficas de um viveiro de camarão, sendo possível seu uso como biofiltro.