Geochemistry and mineralogy of southwestern Lake Superior sediments with an emphasis on phosphorus lability     

Tonello  Maurício S.  Hebner  Tayler S.  Sterner  Robert W.  Brovold  Sandra  Tiecher  Tales  Bortoluzzi  Edson C.  Merten  Gustavo H. 《Journal of Soils and Sediments》2020,20(2):1060-1073

Journal of Soils and Sediments - The lability of phosphorus (P) in Lake Superior sediments and its relationship with sediment mineralogy and geochemistry remains poorly understood. The purpose of...  相似文献   

Toxicity of imidacloprid to the earthworm Eisenia andrei and collembolan Folsomia candida in three contrasting tropical soils     

Bandeira  Felipe Ogliari  Alves  Paulo Roger Lopes  Hennig  Thuanne Bráulio  Schiehl  Aline  Cardoso  Elke Jurandy Bran Nogueira  Baretta  Dilmar 《Journal of Soils and Sediments》2020,20(4):1997-2007

Purpose

Imidacloprid is a widely used seed dressing insecticide in Brazil. However, the effects of this pesticide on non-target organisms such as soil fauna still present some knowledge gaps in tropical soils. This study aimed to assess the toxicity and risk of imidacloprid to earthworms Eisenia andrei and collembolans Folsomia candida in three contrasting Brazilian tropical soils.

Materials and methods

Acute and chronic toxicity assays were performed in the laboratory with both species in a tropical artificial soil (TAS) and in two natural soils (Oxisol and Entisol), at room temperature of 25 °C. The ecological risk was calculated for each species and soil by using the toxicity exposure ratio (TER) and hazard quotient (HQ) approaches.

Results and discussion

Acute toxicity for collembolans and earthworms was higher in Entisol (LC₅₀?=?4.68 and 0.55 mg kg^?1, respectively) when compared with TAS (LC₅₀?=?10.8 and 9.18 mg kg^?1, respectively) and Oxisol (LC_{50collembolans}?=?25.1 mg kg^?1). Chronic toxicity for collembolans was similar in TAS and Oxisol (EC_{50 TAS}?=?0.80 mg kg^?1; EC_{50 OXISOL}?=?0.83 mg kg^?1), whereas higher toxicity was observed in Entisol (EC₅₀?=?0.09 mg kg^?1). In chronic assays with earthworms, imidacloprid was also more toxic in Entisol (EC₅₀?=?0.21 mg kg^?1) when compared to TAS (EC₅₀?=?1.89 mg kg^?1). TER and HQ values indicated a significant risk of exposure of the species to imidacloprid in all soils tested, and the risk in Entisol was at least six times higher than in Oxisol or TAS.

Conclusions

The toxicity and risk of imidacloprid varied significantly between tropical soils, being the species exposure to this pesticide particularly hazardous in very sandy natural soils such as Entisol.

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Whole cell inactivated autogenous vaccine effectively protects red Nile tilapia (Oreochromis niloticus) against francisellosis via intraperitoneal injection     

Jos Gustavo Ramírez‐Paredes  Miguel Angel Mendoza‐Roldan  Benjamin Lopez‐Jimena  Khalid Shahin  Matthijs Metselaar  Kim D. Thompson  David J. Penman  Randolph H. Richards  Alexandra Adams 《Journal of fish diseases》2019,42(8):1191-1200

Francisella noatunensis subsp. orientalis is a pathogen of tilapia and other warm‐water fish for which no vaccines are commercially available. In this study, a whole cell formalin‐inactivated vaccine was developed for the first time using the highly virulent isolate STIR‐GUS‐F2f7 and the oil‐based adjuvant Montanide? ISA 763A VG. The efficacy of the vaccine was assessed in red Nile tilapia via intraperitoneal (i.p.) injection using homologous experimental infection and correlates of protection such as seral antibody production and bacterial loads in the spleen. For immunization, fish were i.p. injected with 0.1 ml of the vaccine, the adjuvant alone or PBS. At 840 degree days post‐vaccination, all fish were i.p. injected with 4.0 × 10³ CFU/fish of pathogenic bacteria. The RPS at the end of the trial was 100% in the vaccinated group with significantly higher survival than in the adjuvant and control groups. The RPS in the adjuvant group was 42%, and no significant difference was seen in survival between this and the PBS group. Moreover, significantly higher antibody titres in the serum and significantly lower bacterial loads in the spleen were detected in the vaccinated fish by ELISA and qPCR, respectively. These findings highlight the potential of autogenous vaccines for controlling francisellosis in tilapia.  相似文献   

Long‐term changes in fishery resources of an estuary in southwestern Atlantic according to local ecological knowledge     

Vinni Santos Thykjaer  Lucas dos Santos Rodrigues  Manuel Haimovici  Luís Gustavo Cardoso 《Fisheries Management and Ecology》2020,27(2):185-199

Long‐term changes in the abundance of fisheries resources from the Patos Lagoon estuary and adjacent coastal waters in southern Brazil have been observed. Despite this understanding, it is well known that the perception of pristine state of the environment is susceptible to inter‐generational changes, commonly known as shifting baseline syndrome (SBS). An useful approach in the reconstruction of pristine scenarios and in lack of data, as often occurs in small‐scale fisheries, is the local ecological knowledge (LEK). Temporal changes in the perception of 81 fishers with 1–63 years of fishing about the resources status were analysed. More experienced fishers reported larger catches, heavier individuals and perceived a greater number of species as "scarce" nowadays and "common" at the beginning of their careers proving the existence of a SBS among them. Over time, the number of fishing sites with very high catches decreased and fishing sites shifted from the lower towards the upper estuary. The perception of the fishers corroborated the real decreasing scenario in estuarine fisheries resources shared with industrial fishing in coastal waters. The results reinforce the utility of LEK for reconstruction of biological scenarios when no empirically obtained data are available.  相似文献   

Comparing skeletal development of wild and hatchery-reared Senegalese sole (Solea senegalensis, Kaup 1858): evaluation in larval and postlarval stages     

Paulo Jorge Gavaia  Susana Domingues  Sofia Engrola  Pilar Drake  Carmen Sarasquete  M Teresa Dinis  & M Leonor Cancela 《Aquaculture Research》2009,40(14):1585-1593

The Senegalese sole is a marine pleuronectiform that naturally occurs in Southern Europe and Mediterranean region where it is being produced in aquaculture, in particular in Portugal and Spain. The aim of this study was to assess the quality of hatchery-reared larvae in comparison with those reared in the wild, and determine to which extension wild growing larvae are also affected by skeletal deformities. The main structures affected included those forming the axial skeleton, the caudal fin complex and both anal and dorsal fins, with the most prevalent anomalies affecting caudal vertebrae and arches. Hatchery-reared fish presented a higher incidence of deformities (79%) compared with the 19% observed in wild specimens. In wild postlarvae collected in Autumn no deformities were observed. This work clearly shows that wild Senegalese sole present less skeletal deformities than those hatchery-reared during larval stages, indicating a selective mortality of wild deformed fish and/or an effect of aquaculture-related rearing conditions in the development of skeletal deformities in sole.  相似文献   

Is there a blue transition underway?     

Laura Nahuelhual  Omar Defeo  Ximena Vergara  Gustavo Blanco  Sandra L. Marín  Fabio Bozzeda 《Fish and Fisheries》2019,20(3):584-595

In this study, we describe what we term a Blue Transition, defined as the passage from fish biomass reduction to recovery in exploited aquatic resources, enabled by aquaculture. A Blue Transition is a key component of emergent “blue” discourses which support that the expansion of aquaculture would relieve pressure on declining capture fisheries, thus contributing to global food security, particularly of the poorest populations. Based on global secondary data and the case of Chile, we explore the evidence of such claim and the implications of a Blue Transition for fisheries and aquaculture development. In 2012, worldwide aquaculture production surpassed wild captures; nevertheless, such turnaround would have not taken place without China's contribution. In Chile, this turnaround occurred in 2014, concurrently with the lowest industrial landings registered since the 1960s (1,227,359 tons). Chile's aquaculture is not relieving wild fisheries or satisfying food demands of the lower income population, in the country or elsewhere. Salmon, the main aquaculture product, is destined mainly to Japan, Russia and United States where, due to its high prices, it is consumed mostly by wealthy consumers. For the case at hand, evidence suggests that a blue transition may be underway but is going in the wrong direction: from what may have been sustainable fisheries management before the 1970s to the overexploited wild fisheries of today.  相似文献   

Ammonia‐, Sodium Chloride‐, and Calcium Sulfate‐induced Changes in the Stress Responses of Jundiá, Rhamdia quelen,Juveniles     

Paulo César Falanghe Carneiro  Elaine Correa Swarofsky  Daniana Pinotti E. Souza  Thiago Mocelin Ramos César  Bárbara Baglioli  Bernardo Baldisserotto 《Journal of the World Aquaculture Society》2009,40(6):810-817

Salt (NaCl) and gypsum (CaSO₄) are used as water additives to mitigate fish stress and improve specimen survival. High stocking densities and the transportation of fish can increase aqueous ammonia, which can, in turn, alter fish cortisol secretion. The objectives of this study were to assess the effects of salt, gypsum, and aqueous ammonia on some stress‐induced physiological responses of jundiá, Rhamdia quelen, juveniles induced by captivity and handling, and to determine the lethal ammonia concentration for this species. Jundiá juveniles were subjected to the following five treatments: water only, water + ammonia (0.4 mg/L), water + NH₃ + NaCl (6 g/L), water + NH₃ + gypsum (150 mg/L), and water + NH₃ + NaCl + gypsum. Blood samples were taken after intervals of 1, 5, 24, and 96 h, and the concentrations of cortisol, glucose, chloride, ammonia, and hematocrit were determined. The NH₃ LC₅₀ value after 96 h of exposure (LC_50?96h) was measured to be 1.9 mg/L NH₃. Either salt or gypsum reduced both cortisol and glucose levels during most of the experimental period, but the combination of both reduced these levels even further. The combined use of NaCl and CaSO₄ demonstrates a synergic effect on mitigating stress responses induced by handling and aqueous ammonia in jundiá juveniles.  相似文献   

Reproductive cycle of the Amazonian planktivorous catfish Hypophthalmus marginatus (Siluriformes,Pimelodidae)     

Patrick Hainfellner  Rafael Yutaka Kuradomi  Thiago Gonalves de Souza  Rafael Tomoda Sato  Daniel Guimares Figueiredo‐Ariki  Guilherme Antnio de Freitas  Luciano Queiroz  Wagner C. Valenti  Patricia Moraes Valenti  Wei Ge  Sergio Ricardo Batlouni 《Aquaculture Research》2019,50(11):3382-3391

We evaluated the annual process of oocyte and ovarian development of the planktivorous Amazonian catfish, the mapará (Hypophthalmus marginatus), aiming to support captive reproduction for domestication. A total of 149 females were captured from the Tocantins River at the Tucuruí Dam (3°49'55"S, 49°39'9"W) in 13 sampling events. For each individual, we evaluated ovary histology and plasma steroid concentrations. Two annual reproductive cycles, with similar characteristics, including a long period of rest, a short vitellogenic stage and a well‐defined spawning season from November to March, were described. A 17β‐estradiol (E₂) rise and a 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (DHP) peak were associated with vitellogenesis and spawning season, respectively, in the first cycle but not in the second reproductive cycle. In conclusion, the studied species presents a reproductive cycle similar to that of other migratory total spawners; however, unusually for this group of fish, there were three (but not two) batches of vitellogenic oocytes in “in maturation” and “mature” stage ovaries, pointing to the possibility of more than one spawn during the spawning season.  相似文献   

Oregano (Origanum vulgare) essential oil as an additive in diets for Nile tilapia (Oreochromis niloticus) fingerlings reared in salinized water     

Guilherme Melgao Heluy  Leonardo Rocha Vidal Ramos  Virgínia Fonseca Pedrosa  Cristiane Sarturi  Paulo Gustavo Pires Figueiredo  Letícia Gabriela Poblete Vidal  Igor de Fiuza Frana  Marcelo Maia Pereira 《Aquaculture Research》2020,51(8):3237-3243

The present study was undertaken to examine the effects of oregano essential oil on the growth performance, blood glucose levels, body composition and intestinal morphometry of Nile tilapia reared in salinized water at 10 g/L for 64 days. The experiment was set up as a completely randomized design with five treatments and four replicates, in which a control diet and four diets containing increasing concentrations of oregano essential oil (0.75, 1.5, 2.25 and 3.0 g/kg) were tested. The best results for the growth parameters were obtained with the oregano essential oil inclusion level of 0.75 g/kg, but did not differ (p > .05) from inclusion levels of 0.0, 2.25 and 3.0 g/kg. Conversely, the treatment including the oil level of 1.5 g/kg was the only one to produce significantly (p < .05) lower results. The body composition and blood glucose were not significantly affected. Intestinal morphometry analysis revealed a significant effect on villus length, which increased with the proportion of oregano essential oil added to the diet; accordingly, the inclusion level of 3.0 g/kg provided the best results for this variable. Therefore, the addition of oregano essential oil at 3.0 g/kg in the diet of Nile tilapia cultured in salinized water may act as a stimulant to intestinal villus development and, consequently, as a growth promoter.  相似文献   

Multi-trait stability index: A tool for simultaneous selection of soya bean genotypes in drought and saline stress     

Alan Mario Zuffo  Fábio Steiner  Jorge González Aguilera  Paulo Eduardo Teodoro  Larissa Pereira Ribeiro Teodoro  Aécio Busch 《Journal of Agronomy and Crop Science》2020,206(6):815-822

Drought and salinity are the main limiting environmental factors that restrict the establishment of soya bean plants. In order to recommend genotypes for cultivation under adverse drought and saline stress conditions, multi-environment trials (MET) are needed. However, MET analysis is usually performed considering a single trait, which provides lower reliability in recommending genotypes when compared to multi-trait analysis. Thus, this study was carried out to investigate the stability of multi-trait stability index (MTSI) in 46 soya bean cultivars under the effects of drought and saline stress on seed germination and initial seedling growth. Drought and saline stresses were imposed by seed exposure to −0.20 MPa iso-osmotic solutions with polyethylene glycol—PEG 6000 (119.6 g/L) or NaCl (2.36 g/L) for 12 days at 25°C. The germination rate, seedling length and seedling dry matter were measured. We showed here how genotypic stability can be quantified by MTSI when comparing drought and salinity conditions in relation to non-stressful environment (control) and how this index can be employed under different conditions. When considering the index for multiple environments, we can select as the most stable genotypes TMG 716 RR, FPS Antares RR, AS 3610 IPRO, NS 7300 IPRO and FPS Solar IPRO among the 46 tested genotypes. Owing to high stability and gains with selection verified for these genotypes under salinity and drought conditions, they can be used as genitors in breeding programs aimed at obtaining offspring with higher resistance to antibiotic stresses.  相似文献