Acclimation Time Research Articles

Comparing Survival and Cause-Specific Mortality of Different Translocation Release Methods for Desert Bighorn Sheep

Historically, desert bighorn sheep (Ovis canadensis mexicana) were prevalent throughout the Trans-Pecos region of Texas. However, they were extirpated by the 1960s due to unregulated hunting, habitat loss, predation, and disease transmission from livestock. Restoration efforts have been successfully conducted by the Texas Parks and Wildlife Department to increase population numbers of resident (i.e., animals that currently populate a region of interest) desert bighorn sheep at Black Gap Wildlife Management Area (BGWMA) through the use of translocations. Because there is a lack of knowledge on alternative release methods for large mammal translocations, our goals were to monitor cause-specific mortality and postrelease survival of desert bighorn sheep translocated during 2017. Survival estimates of desert bighorn sheep were compared amongst resident, hard-released, and soft-released individuals throughout the study. In winter 2017–2018, we radio-collared and released 30 resident (8 M, 22 F) and 70 within-state-translocated (36 M, 34 F) desert bighorn to BGWMA. Of the 70 translocated individuals, 28 (12 M, 16 F) were hard released (i.e., released immediately onto the landscape) and 42 (24 M, 18 F) were soft released (i.e., released into an enclosure before onto the landscape). Resident desert bighorn had the highest probability of survival over time (Ŝ = 0.83), followed by hard-released (Ŝ = 0.67) and then soft-released (Ŝ = 0.54) individuals. To date, 26 mortalities (13 M, 13 F) were recorded. Of those mortalities, 4 were residents (15%), 6 were hard released (23%), and 16 were soft released (62%). The soft release is thought to be a better strategy for translocating large mammals; however, in this study, it did not improve survival. Survival is potentially influenced by acclimation time and individual exit strategy from the soft-release pen, which should be managed for future restoration efforts. Incorporating a flushing-method exit strategy would aid in removing soft-released individuals from the high-fenced pen simultaneously and may increase survival estimates. This could potentially allow individuals to form larger groups when exiting the enclosure and entering the new habitat. The soft-release method is also more costly to implement, which could be challenging for wildlife managers.

Cross-sectional survey of non-invasive indirect blood pressure measurement practices in cats by veterinarians.

This survey of small animal veterinarians endeavored to: (1) determine current methods of indirect blood pressure measurement; (2) detail techniques used to reduce situational hypertension; and (3) better understand the obstacles to performing blood pressure measurement in cats. An online survey was produced and circulated to members of the Veterinary Information Network. A total of 733 veterinarians who saw cats in their practice and had access to at least one indirect blood pressure device completed the entirety of the survey. Ninety-six percent (703/733) of veterinarians who completed the survey reported measuring indirect blood pressure in cats in their practice, with veterinary technicians conducting most (600/703; 85.3%) of these measurements. Few veterinarians (30/733; 4.1%) did not measure blood pressure, with these veterinarians citing several obstacles including: difficulty interpreting results with the occurrence of fear, anxiety and stress in cats (20/30; 66.7%); difficulty performing measurements in cats (17/30; 56.7%); and technical staff being uncomfortable performing measurements (12/30; 40.0%). Most veterinarians (300/435; 69.0%) in this survey preferred an ultrasonic Doppler flow detector with sphygmomanometry, with many (272/300; 90.7%) perceiving that the results obtained with this device were more trustworthy compared with results obtained with oscillometry. Ninety percent (633/703) of veterinarians employed techniques to reduce situational hypertension in cats. Techniques perceived to be most helpful among veterinarians included: using a quiet location (454/633; 71.7%); minimizing restraint (316/633; 49.9%); performing blood pressure prior to other procedures (eg, phlebotomy, cystocentesis) (302/633; 47.7%); avoiding other animals (219/633; 34.6%); and allowing time for acclimation (167/633; 26.4%). This survey study of veterinarians helps clarify obstacles to routine blood pressure measurement in conscious cats. Veterinarians reported several strategies that they felt reduced situational hypertension in cats. The data inform modifications of techniques to increase the frequency and perceived reliability of blood pressure measurement in at-risk cats.

Short-term thermal acclimation modulates predator functional response.

Phenotypic plastic responses to temperature can modulate the kinetic effects of temperature on biological rates and traits and thus play an important role for species adaptation to climate change. However, there is little information on how these plastic responses to temperature can influence trophic interactions. Here, we conducted an experiment using marbled crayfish and their water louse prey to investigate how short‐term thermal acclimation at two temperatures (16 and 24°C) modulates the predator functional response. We found that both functional response parameters (search rate and handling time) differed between the two experimental temperatures. However, the sign and magnitudes of these differences strongly depended on acclimation time. Acclimation to 16°C increased handling time and search rate whereas acclimation to 24°C leads to the opposite effects with shorter handling time and lower search rate for acclimated predators. Moreover, the strength of these effects increased with acclimation time so that the differences in search rate and handing time between the two temperatures were reversed between the treatment without acclimation and after 24 h of acclimation. Overall, we found that the magnitude of the acclimation effects can be as strong as the direct kinetic effects of temperature. Our study highlights the importance of taking into account short‐term thermal plasticity to improve our understanding of the potential consequences of global warming on species interactions.

Investigation of absolute intra-rater and inter-rater reliabilities during the muscle hardness estimation.

[Purpose] This study aimed to investigate the absolute intra-rater and inter-rater reliabilities during the measurement of muscle hardness, which is used to evaluate physical therapy. Moreover, we examined the effects of using different equipment types and their positioning on the intra-rater and inter-rater reliabilities. [Participants and Methods] Participants of this study comprised 12 healthy adult male individuals. Two experts and two beginners measured the muscle hardness of the lumbar erector spinae and rectus femoris using three types of hardness meters at two positions, including when the muscle was relaxed and stretched. [Results] Intra-rater fixed bias was observed during some measurements by both experts and beginners. Inter-rater fixed bias was observed during measurements by some experts and not the beginners. [Conclusion] In this study, the measurement of muscle hardness demonstrated a need to reconsider the measurement position and acclimation time. These examinations require the consideration of relative and absolute reliabilities.

Gene Expression under Short-Term Low Temperatures: Preliminary Screening Method to Obtain Tolerant Citrus Rootstocks

Climate change and global warming are leading to a change in weather patterns toward hot and cold waves. Citrus fruits are a tropical or subtropical crop whose growth is altered by changes in weather patterns. Thus, in the present work, two experiments are evaluated to obtain a screening method to select citrus rootstocks that help us to select new low-temperature-tolerant plant materials. One cold experiment was carried out with the Poncirus trifoliata and Citrus macrophylla rootstocks at 4 °C for 4, 8, 24 and 56 h. A second experiment was performed at 4 °C for 5 days with subsequent acclimatization lasting 0, 5, 10 and 24 h. The expression of the cold response genes CAMTA1, CAMTA3, CAMTA5, CBF1, ICE1 and COR413 IM1 was quantified. The results showed that the best rootstock selection strategy was the second experiment, as a higher expression of the genes CAMTA3, CAMTA5, CBF1 and COR413 IM1 was seen in the tolerant genotype P. trifoliata. We quantified the gene expression of proline biosynthesis P5CS1, dOAT and the proline transporters PROT1 and PROT2; the concentration of the amino acid proline in leaves was also quantified. These results once again showed that the best experiment to differentiate between tolerant and sensitive rootstocks was the second experiment with acclimation time.

Effects of thermal acclimation and ecological background on the physiological responses of juvenile Oreochromis esculentus (Graham, 1928). Implications for the species adaptive capacity to global warming

Climate change is a recognized global concern in the 21st century. Water temperature elevation is likely to affect fish physiological and ethological function, causing great economic losses for fisheries resources and aquaculture production. Fish are particularly vulnerable to climate change as they are unable to control their body temperatures with changes in environmental temperature. This study assessed the effects of thermal acclimation in three juvenile populations of Oreochromis esculentus on the critical thermal maximum CTmax, cortisol, biochemical and haematological responses to acute temperature increase (0.3°Cmin−1). Fish from Senya farm, Lake Kacheera and Lake Nabisojjo were acclimated at 25°C, 28°C, 31°C and 34°C for 21 days at Kajjansi aquaculture research and development centre KARDC. The CTmax and blood cell counts increased, while plasma cortisol, glucose and proteins decreased at higher acclimation temperatures. Two-way ANOVA showed significant differences among treatments in CTmax, cortisol, proteins and erythrocytes indices, but not in glucose and leucocytes. However, significant variations among populations were only showed in CTmax. Overall, these results suggest that O. esculentus can respond to higher climate change induced temperatures, when allowed time for acclimation. Since temperature adaptation not only depends on the parameters assessed in this study, we recommend further investigations into metabolic rate and digestive enzymatic activity.

Temperature (but not acclimation) affects hearing in fishes adapted to different temperature regimes

Temperature affects various metabolic and physiological processes in ectothermic animals, including auditory systems. The current study investigates the effect of temperature and thermal acclimation time on hearing sensitivities in a eurythermal and a stenothermal fish possessing accessory hearing structures. Using the auditory evoked potential (AEP) recording technique, we determined thresholds from 0.1 to 4 kHz and peak latencies of AEP-waveforms in response to a click stimulus. The goldfish Carassius auratus was chosen as a model for eurythermal and the Amazonian catfish Megalodoras uranoscopus as a model for stenothermal species. Both species were tested at two different temperatures (C. auratus: 15 °C and 25 °C, M. uranoscopus: 22 °C and 30 °C) and acclimation periods, within 22 h (unacclimated) or three to four weeks (acclimated) after reaching the target temperature. A frequency-dependent increase in auditory sensitivity and a decrease of peak latencies was recorded in both species at higher temperatures, independent of acclimation time. The change in hearing thresholds per degree Celsius was more pronounced in the stenothermal catfish. The data indicate that higher temperatures improved hearing (lower thresholds, shorter latencies), whereas acclimation had no effect on hearing in either species. The latter data contradict previous findings in the eurythermal channel catfish Ictalurus punctatus in which acclimation slightly improved hearing when raising the temperatures. A comparison of changes in hearing sensitivity per degree Celsius of all seven species tested so far revealed no differences between eurythermal and stenothermal species.

Effects of thermal conditioning on the performance of Pocillopora acuta adult coral colonies and their offspring

Ocean warming induced by climate change is the greatest threat to the persistence of coral reefs globally. Given the current rate of ocean warming, there may not be sufficient time for natural acclimation or adaptation by corals. This urgency has led to the exploration of active management techniques aimed at enhancing thermal tolerance in corals. Here, we test the capacity for transgenerational acclimation in the reef-building coral Pocillopora acuta as a means of increasing offspring performance in warmer waters. We exposed coral colonies from a reef influenced by intermittent upwelling and constant warm-water effluent from a nuclear power plant to temperatures that matched (26 °C) or exceeded (29.5 °C) season-specific mean temperatures for three reproductive cycles; offspring were allowed to settle and grow at both temperatures. Heated colonies reproduced significantly earlier in the lunar cycle and produced fewer and smaller planulae. Recruitment was lower at the heated recruitment temperature regardless of parent treatment. Recruit survival did not differ based on parent or recruitment temperature. Recruits from heated parents were smaller and had lower maximum quantum yield (Fv/Fm), a measurement of symbiont photochemical performance. We found no direct evidence that thermal conditioning of adult P. acuta corals improves offspring performance in warmer water; however, chronic exposure of parent colonies to warmer temperatures at the source reef site may have limited transgenerational acclimation capacity. The extent to which coral response to this active management approach might vary across species and sites remains unclear and merits further investigation.

NMR-based metabolomics approach on optimization of malolactic fermentation of sea buckthorn juice with Lactiplantibacillus plantarum

This work investigated the impact of malolactic fermentation on the metabolomic profile of sea buckthorn juice to optimize the fermentation process for flavor modification. Six strains of L. plantarum were used with varied pH of the juice, cell acclimation, and fermentation time. 1H-NOESY spectra were acquired from fresh and fermented juices with a total of 46 metabolites identified. Less sugars and quinic acid were metabolized at pH 2.7 while oxidation of ascorbic acid was reduced at pH 3.5. l-Malic acid, essential amino acids, and nucleosides were consumed early during fermentation while sugars in general were consumed later in the fermentation. If deacidification is the main target of fermentation, strains that produce less acids and ferment less sugars, shorter fermentation time, and lower starter pH should be used. Higher starter pH and longer fermentation time promote formation of antimicrobial compounds and potentially increase antioxidant stability.

Evaluating tank acclimation and trial length for dynamic shuttle box temperature preference assays in aquatic animals.

Characterizing the thermal preference of fish is important in conservation, environmental and evolutionary physiology and can be determined using a shuttle box system. Initial tank acclimation and trial lengths are important considerations in experimental design, yet systematic studies of these factors are missing. Three different behavioral assay experimental designs were tested to determine the effect of tank acclimation and trial length (hours of tank acclimation:behavioral trial: 12:12, 0:12, 2:2) on the temperature preference of juvenile lake whitefish (Coregonus clupeaformis), using a shuttle box. Average temperature preferences for the 12h:12h, 0h:12h, 2h:2h experimental designs were 16.10±1.07°C, 16.02±1.56°C and 16.12±1.59°C respectively, with no significant differences between experimental designs (P=0.9337). Ultimately, length of acclimation time and trial length had no significant effect on thermal preference.

Acartia tonsa Dana 1849 as a Model Organism: Considerations on Acclimation in Ecotoxicological Assays.

The copepod Acartia tonsa was standardized as model organism in acute toxicity bioassays due to its key position in coastal food chains and high sensitivity. Once bioassays are performed according to a protocol their results may become tools for the protection of aquatic ecosystems. However, there are divergences in bioassays methods using A. tonsa. This study aimed to investigate: (i) the need for acclimation of A. tonsa collected from the environment for use in acute toxicological bioassays; and (ii) differences in sensitivity between copepods collected from the environment and laboratory-grown copepods. Laboratory-grown copepods are more sensitive to SDS thanA. tonsa from theenvironment. The acclimation time of 30h helped organisms to recover from stress of collection/handling and changing environment/conditions. Therefore, laboratory-grown copepods showed to be more sensitive than organisms from environment; and for ecotoxicological bioassays acclimating A. tonsa collected from the environment for 30h can be adopted.

Effects of influent composition on biological activity, acclimation time and microbial community profile of activated sludge

Background: The performance and stability of activated sludge (AS) processes are strongly related to influent wastewater characteristics. Objective: To investigate the influence of different chemical compositions of influent wastewater, in terms of source of carbon, on activated sludge. Methods: Response was measured in oxygen uptake rate (OUR), volatile suspended solids in the mixed liquor (MVLSS), chemical oxygen demand (COD), and microbial community profile, obtained using Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Results: Results showed that the microbial community profile obtained in both reactors is consistent with those reported for full-scale AS bioreactors treating sewage. However, when the source of carbon is less bioavailable (bioreactor 1), there was a statistically significant difference (p-value<0.05, 95% confidence) in the biological activity of the biomass, both in terms of MLVSS growth and OUR in comparison with the reactor with source of carbon more bioavailable (bioreactor 2). This difference also impacted the time required for complete acclimation: it could be considered completed in 15 days in bioreactor 2, whereas in bioreactor 1, acclimation required more than 120 days to be completed, as during this period there was no net biomass growth even though there was high COD removal.

Acclimation and adaptation to elevated pCO2 increase arsenic resilience in marine diatoms.

Arsenic pollution is a widespread threat to marine life, but the ongoing rise pCO2 levels is predicted to decrease bio-toxicity of arsenic. However, the effects of arsenic toxicity on marine primary producers under elevated pCO2 are not well characterized. Here, we studied the effects of arsenic toxicity in three globally distributed diatom species (Phaeodactylum tricornutum, Thalassiosira pseudonana, and Chaetoceros mulleri) after short-term acclimation (ST, 30 days), medium-term exposure (MT, 750 days), and long-term (LT, 1460 days) selection under ambient (400 µatm) and elevated (1000 and 2000 µatm) pCO2. We found that elevated pCO2 alleviated arsenic toxicity even after short acclimation times but the magnitude of the response decreased after mid and long-term adaptation. When fed with these elevated pCO2 selected diatoms, the scallop Patinopecten yessoensis had significantly lower arsenic content (3.26-52.83%). Transcriptomic and biochemical analysis indicated that the diatoms rapidly developed arsenic detoxification strategies, which included upregulation of transporters associated with shuttling harmful compounds out of the cell to reduce arsenic accumulation, and upregulation of proteins involved in synthesizing glutathione (GSH) to chelate intracellular arsenic to reduce arsenic toxicity. Thus, our results will expand our knowledge to fully understand the ecological risk of trace metal pollution under increasing human activity induced ocean acidification.

New insights into the effect of ethanol and volatile fatty acids proportions on methanogenic activities and pathways

During anaerobic digestion, methanogenic activities and pathways can be affected by intermediates. Here, the effects of intermediates acetate, propionate, and ethanol on methanogenesis were investigated. Four anaerobic sequencing batch reactors were acclimated with propionate (ASBR_P), ethanol/propionate (ASBR_EP), acetate/propionate (ASBR_AP), and ethanol/acetate/propionate (ASBR_EAP). Ethanol was the easiest one to be biodegraded, thereby enhancing the maximum methane production rate and shortening the lag phase, while the longest acclimation time and lowest methane production rate were observed in ASBR_P. Different microbial communities and syntrophic patterns existed in four reactors. Desulfovibrio and Geobacter were the dominant ethanol-oxidizing bacteria in ASBR_EP and ASBR_EAP, respectively. Both Desulfovibrio and Geobacter possessed the potential of extracellular electron transfer, which might be the advantage of ethanol dosage for enhancing methanogenesis through direct interspecies electron transfer. Methanosarcina was enriched in ASBR_P and ASBR_AP, while Methanosaeta in ASBR_EP and ASBR_EAP. Genes responsible for acetoclastic methanogenesis were significantly enriched in ASBR_EAP, possibly resulting in the highest methanogenic activity from acetate. Results from this study will advance the optimization of practical anaerobic systems, which can be achieved by regulating the intermediates with different fermenting pathways.

Feeding rate and efficiency in an apex soil predator exposed to short-term temperature changes

As extreme climate events become more frequent and intense, short-term temperature responses of ectothermic organisms can lead to decreased performance and survival. However, organisms may acclimate to these conditions through behavioural and physiological mechanisms as exposure time increases. We used a reciprocal temperature (16 °C and 24 °C) transplant experiment to determine how feeding rate and body size of an apex soil mite predator (Stratiolaelaps scimitus) (formerly Hypoaspis miles) consuming prey (Carpoglyphus lactis) (dried-fruit-mite) changed along a gradient of acclimation time (1, 3, and 7 days, with control). In the control treatments, mites reared at 24 °C fed more, but were smaller than mites reared at 16 °C. When transferred to new temperature conditions, predators that experienced cooling events had reduced feeding efficiencies driven by decreased feeding performance, despite an absence of metabolic costs, while under warming events, predators also had reduced feeding activity, but feeding increased with acclimation time. Yet predators lost more weight the longer they were exposed to warming, and continued to experience reduced feeding efficiencies (i.e., lack of weight gain after feeding); this result suggests increased metabolic costs at higher temperatures and provides a mechanism for community downsizing under warming. Overall, our results suggest that ectothermic predators can acclimate to warming events with increased exposure time, but both warming and cooling events decrease overall performance.

Deep body and surface temperature responses to hot and cold environments in the zebra finch.

Global warming increasingly challenges thermoregulation in endothermic animals, particularly in hot and dry environments where low water availability and high temperature increase the risk of hyperthermia. In birds, un-feathered body parts such as the head and bill work as 'thermal windows', because heat flux is higher compared to more insulated body regions. We studied how such structures were used in different thermal environments, and if heat flux properties change with time in a given temperature. We acclimated zebra finches (Taeniopygia guttata) to two different ambient temperatures, 'cold' (5°C) and 'hot' (35°C), and measured the response in core body temperature using a thermometer, and head surface temperature using thermal imaging. Birds in the hot treatment had 10.3°C higher head temperature than those in the cold treatment. Thermal acclimation also resulted in heat storage in the hot group: core body temperature was 1.1°C higher in the 35°C group compared to the 5°C group. Hence, the thermal gradient from core to shell was 9.03°C smaller in the hot treatment. Dry heat transfer rate from the head was significantly lower in the hot compared to the cold treatment after four weeks of thermal acclimation. This reflects constraints on changes to peripheral circulation and maximum body temperature. Heat dissipation capacity from the head region increased with acclimation time in the hot treatment, perhaps because angiogenesis was required to reach peak heat transfer rate. We have shown that zebra finches meet high environmental temperature by heat storage, which saves water and energy, and by peripheral vasodilation in the head, which facilitates dry heat loss. These responses will not exclude the need for evaporative cooling, but will lessen the amount of energy expend on body temperature reduction in hot environments.

Acclimation of Isochrysis galbana Parke (Isochrysidaceae) for enhancing its tolerance and biodegradation to high-level phenol in seawater

Marine microalgae with high removal efficiency of phenol are needed for the remediation of polluted seawater in cases involving phenol spills. To achieve this purpose, adaptive laboratory evolution (ALE) was performed by a microalga Isochrysis galbana Parke MACC/H59, which is capable of degrading phenol at concentrations of less than 100 mg L−1 in 4 d. Two acclimation conditions were used: (i) 90 d at 100 mg L−1 phenol, and (ii) 90 d at 100 mg L−1 phenol followed by another 90 d at 200 mg L−1 phenol. By doing so, two strains (PAS-1 and PAS-2) could be obtained respectively. They grew rapidly at phenol concentrations up to 200 mg L−1 and 300 mg L−1, respectively, with a specific growth rate 2.52–3.40 times and 1.93–3.23 times that of the control (without phenol). Also, both strains had a higher removal capacity of phenol than the unacclimated alga. Phenol at an initial concentration of 200 mg L−1 was completely removed in 5 d thereby. For 300 mg L−1 phenol, a removal efficiency of 92% was achieved in 10 days by using PAS-2, with a removal rate constant of 30.01 d−1 (about twice that of PAS-1) and a half-life of 4.90 d (about half that of PAS-1), showing that a better strain may be obtained by extending the acclimation time. The enhancement of phenol biodegradation can be explained by the elevated activity of phenol hydroxylase (PH) in both strains. These results indicated that ALE could be an efficient tool used to enhance the tolerance and biodegradation of marine microalgae to phenol in seawater.

Techno-economic preferability of cost-performance effective draw solutions for forward osmosis and osmotic anaerobic bioreactor applications

Cost and performance efficient integrations of biological treatments with membrane processes are very worthy for water and resource recovery among of which osmotic anaerobic digestion suffers from exactly elucidating desirable techno-economic features of key operating factors. Cost-performance effective draw solutions (DSs) were ascertained for forward osmosis (FO) and its anaerobic bioreactor (AnBR) configurations, anaerobic osmotic membrane bioreactor (AnOMBR) and [FO/AnBR]. In case study comprising literature data pre-screening, selected DS experiments, and preferability analysis, dual modeling was executed for prioritizing DSs eligible to osmotic AnBRs by analytic hierarchy process (AHP). Through AHP screening of 29 DSs' FO data, NaNO3, NaCl, MgCl2, CaCl2, NH4H2PO4, HCOONa and CH3COONa were established between the best 10% worth researching for osmotic AnBRs. Experiments showed that isothermally varied temperatures hardly affected DS performances in submerged, but DS concentration raises led to those distinguished by reverse solute fluxes. Reverse solute flux selectivity was differed significantly by DS kinds and FO configurations because of varying interactions among predominant inorganic ion and soluble organics. Submerged FO fed by distilled water provided better performance than sidestream but not by wastewater. Anaerobic bioactivities showed longer acclimation times increased by alkalinity unlike seawater (SW) and better CH4 productivity of organics enhanced by DS concentration. Upon AHP analyses, CaCl2, MgCl2, both organics, and SW were more techno-economically favorable DS kinds. Irrespective of technological alternatives, CaCl2 and MgCl2 were found as top two except just SW was the best for AnOMBR by low-cost supply. It was finally proved that eligible DSs should be designated technology-dependently due to their distinctive performances and replenishment costs, and topmost priority to SW should be attributed in sustainable wastewater reclamations by AnOMBR in coastal countries.

Temporary addition of carbon fibers facilitates methanogenic degradation of ethanol during anaerobic treatment

Syntrophic methanogenesis can be improved by the addition of conductive materials. In this study, conductive carbon fibers (CFs) were applied to efficiently enrich syntrophic microorganisms with potential direct interspecies electron transfer (DIET) ability and promote methanogenic activity. With ethanol as the substrate, CFs shortened the acclimation time remarkably. The maximum methane production rate and the ethanol degradation rate of suspended biomass were increased by 40% and 68%, respectively, even when CFs were subsequently removed. However, with acetate and propionate as the mixed substrate, CFs decreased the methanogenic activity. In the reactor fed with ethanol, CFs increased the relative abundance of Geobacter, Desulfovibrio, and methanogens by 57%, 39%, and 63%, respectively. Methanosaeta possessed most methane production genes and might involve in DIET. Furthermore, CFs increased the relative abundance of ethanol-degradation genes assigned to Geobacter, Desulfovibrio and Pelobacter, suggesting the promoted ethanol-degradation. The triggered electron transport system activity and acetoclastic methanogenesis also explained the accelerated effects on ethanol-degradation by long-term acclimation with CFs. Notably, the dominance of Geobacter and Methanosaeta combined with the increased electron transfer constant in the CFs-amended ethanol reactor indicated the potential role of DIET after the removal of CFs, which deserved further clarification.

Removal of bisphenol A by waste zero-valent iron regulating microbial community in sequencing batch biofilm reactor

The removal of bisphenol A (BPA) by waste zero-valent iron (ZVI) regulating microbial community in sequencing batch biofilm reactor (SBBR) was investigated. Compared with SBBR-BPA, the acclimation time of microorganisms in the presence of waste ZVI and BPA (SBBR-ZVI+BPA) decreased from 56 d to 49 d. During stable operation period, BPA was removed completely at 150th min and 100th min in the SBBR-BPA and SBBR-ZVI+BPA, respectively. The optimal initial pH and BPA concentration in the SBBRs were respectively 8.0 and 10 mg/L. The composition and content analysis of extracellular polymeric substances (EPS) using fluorescence spectrometer showed that the yield of EPS was enhanced by the addition of ZVI. The analysis of microbial community structure in the SBBRs using Illumina Miseq sequencing method indicated that the indexes of ACE, Chao1 and Shannon were higher and Simpson index was lower in the SBBR-ZVI+BPA. Moreover, the abundance of BPA biodegradation strains was increased in the presence of ZVI. This study provided a promising method with low cost of effectively removing BPA from wastewater.