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The mass-specific metabolic rates of the Antarctic pelagic tunicate Salpa thompsoni Foxton, 1961 were studied during March-April of 1998 and March 2002. The study revealed a large variation in metabolic rates and assessed sources of this variability. The main factors driving variability included density of tunicates in incubation containers (incubation density, e.g. the salp mass per unit volume of the respirometer), diel/circadian rhythms in salps, and spatial variability of their metabolic performance related to the feeding conditions. The mass specific respiration rates of both salp life forms (oozooids and blastozooids) appeared to be independent of their body mass. The salp-specific respiration rates at 3°C were strongly negatively influenced by their incubation density ranging between 2.0 and 90.4 gWW.l−1. Salp respiration rates adjusted to an incubation density of 3 gWW.l−1 in both oozooids and blastozooids followed similar circadian rhythms with the mean respiration rates of 79.5 and 41.5 μg O2 gWW−1 h−1, respectively. Deviation of these rates from actual field-measured respiration rates corrected for the salp density and diel variability during 1998 and 2002 identified effects of food concentrations, i.e. proxy of the plankton community development and composition, on the salp population performance. [ABSTRACT FROM AUTHOR]

Parasites have deleterious effects on their hosts, often resulting in altered host behavior or increased energy expenditure. When organisms are exposed to suboptimal environments, parasite loading may increase. Microbialite pools along the warm temperate South African coastline have been hypothesized as refugia for Epaulette gobies (Coryogalops sordidus, Gobiidae) when they are outside of their previously known subtropical distribution. The aim of this study was to determine if C. sordidus individuals infected with metacercarial cysts display higher metabolic rates or different swimming behavior compared to noninfected individuals. We measured each goby's swimming performance using a critical station‐holding speed (Ucrit) test (n = 60) and visually scored their swimming behavior (n = 52) during these measurements. Also, we measured the metabolic rate of gobies using an intermittent flow respirometer system to determine standard metabolic rate (SMR) and maximum metabolic rate (MMR) from gobies at 21°C before and after swimming trials. Metacercarial load carried by infected gobies seemingly had no impact on the host's energetics (SMR or MMR), swimming ability (as repeated Ucrit tests), or swimming behavior compared to noninfected gobies. Thus, the metacercarial intensity observed in gobies in the current study appeared to have no impact on host swimming performance or behavior. Furthermore, the swimming capacity observed for C. sordidus, in general, suggests that this goby is a poor swimmer compared to other gobiid species. [ABSTRACT FROM AUTHOR]

Platymonas subcordiformis may be deemed a prospective species in terms of its hydrogen production capacity. The efficiency of hydrogen production by these microalgae is affected by the method of sulfur compounds removal from the culture medium, which urges the search for effective separation methods. This study aimed to determine the feasibility of harnessing membrane vacuum filtration (MVF) for P. subcordiformis microalgae biomass separation from the culture medium to boost the hydrogen yield. Its results proved a positive impact of the filtration method on hydrogen production. Higher technological performance due to the use of MVF was recorded in the variants with biomass concentration in respirometers ensured at 5.0 gODM/dm3. In the most effective variant, hydrogen yield after biomass concentration using MVF reached 156.3 ± 11.0 cm3 H2 at the mean production rate of r = 1.38 ± 0.1 cm3/h, whereas after centrifugation the respective values were at 138.3 ± 12.8 cm3 H2 and r = 1.09 ± 0.09 cm3/h. Hydrogen production efficiency was also found to significantly depend on the initial biomass concentration in respirometers and culture medium composition at the stage of biomass cultivation. [ABSTRACT FROM AUTHOR]

There are several methods available to assess energy expenditure, all associated with inherent pros and cons that must be adequately considered for use in specific environments and populations. A requirement of all methods is that they must be valid and reliable in their capability to accurately measure oxygen consumption (VO2) and carbon dioxide production (VCO2). The purpose of this study was to evaluate the reliability and validity of the mobile CO2/O2 Breath and Respiration Analyzer (COBRA) relative to a criterion system (Parvomedics TrueOne 2400®, PARVO) with additional measurements to compare the COBRA to a portable system (Vyaire Medical, Oxycon Mobile®, OXY). Fourteen volunteers with a mean of 24 years old, body weight of 76 kg, and a VO2peak of 3.8 L∙min−1 performed four repeated trials of progressive exercises. Simultaneous steady-state measurements of VO2, VCO2, and minute ventilation (VE) by the COBRA/PARVO and OXY systems were conducted at rest, while walking (23–36% VO2peak), jogging (49–67% VO2peak), and running (60–76% VO2peak). Data collection was randomized by the order of system tested (COBRA/PARVO and OXY) and was standardized to maintain work intensity (rest to run) progression across study trials and days (two trials/day over two days). Systematic bias was examined to assess the accuracy of the COBRA to PARVO and OXY to PARVO across work intensities. Intra- and inter-unit variability were assessed with interclass correlation coefficients (ICC) and a 95% limit of agreement intervals. The COBRA and PARVO produced similar measures for VO2 (Bias ± SD, 0.01 ± 0.13 L·min−1; 95% LoA, (−0.24, 0.27 L·min−1); R2 = 0.982), VCO2 (0.06 ± 0.13 L·min−1; (−0.19, 0.31 L·min−1); R2 = 0.982), VE (2.07 ± 2.76 L·min−1; (−3.35, 7.49 L·min−1); R2 = 0.991) across work intensities. There was a linear bias across both the COBRA and OXY with increased work intensity. The coefficient of variation for the COBRA ranged from 7 to 9% across measures for VO2, VCO2, and VE. COBRA was reliable across measurements for VO2 (ICC = 0.825; 0.951), VCO2 (ICC = 0.785; 0.876), and VE (ICC = 0.857; 0.945) for intra-unit reliability, respectively. The COBRA is an accurate and reliable mobile system for measuring gas exchange at rest and across a range of work intensities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Clark electrode gives reliable O 2 results for metabolic rate calculation in ants. • Ant castes (queens and workers) have different allometric coefficient. Respirometry provides a direct measure of an organism's O 2 consumption rate (VO 2), which is a significant component of its metabolic rate (energy expenditure). Amongst ants, variations in lifespan between different social castes (such as workers and queens) can be substantial, varying depending on the species. As metabolic rate is higher in short-living species, we aimed to determine how VO 2 and longevity may have coevolved within ant casts. Measuring VO 2 in such tiny animal models can be challenging, and as a first methodological step, we validate the use of a Clark electrode, initially designed for measuring mitochondrial respiration control pathways, for assessing VO 2 in ants within a sealed chamber. This was done by comparing it with stop-flow VO 2 and CO 2 production, using a traditional indirect calorimetry device. The global aim is to provide a reliable protocol to conduct accurate comparisons of metabolic rates within and among ant species. As expected, using the Clark electrode entails high time resolution and revealed that queens and workers exhibited discontinuous gas exchange, with episodes of apnea lasting up to 20 min. [ABSTRACT FROM AUTHOR]

Few published studies have measured the oxygen consumption rates of elasmobranchs larger than 1.5 m, with only one measured at temperatures below 10 °C. This study provides initial measurements of the metabolic rate of three juvenile Pacific sleeper sharks, SP1904, SP1908, and SP2005 (199 cm, 162 cm, 144 cm), which were caught and temporarily housed at the Alaska SeaLife Center in Seward, Alaska. While at the Center, multiple respirometry trials were performed utilizing an intermittent-closed system respirometer to measure oxygen consumption. The average routine metabolic rates for each individual were calculated at 17.8 ± 1.3 mgO2kg−1 h−1, 20.5 ± 1.6 mgO2kg−1 h−1, and 4.0 ± NA mgO2kg−1 h−1, respectively, while the resting metabolic rate of SP1908 was calculated at 14.3 ± 2.4 mgO2kg−1 h−1. Oxygen consumption rates were measured between 6.0 and 8.8 °C. Both the active and resting metabolic rates for the Pacific sleeper shark were like those of the previously measured and closely related Greenland shark (Somniosus microcephalus) and the temperate zebra shark (Stegostoma fasciatum) when scaled to the temperature in this study. Therefore, Pacific sleeper shark metabolic rate is not unusually low compared to other shark species. These initial measurements of the metabolic rate of Pacific sleeper sharks enhance deep-sea and polar physiology knowledge by filling gaps in respirometry research for large, Arctic elasmobranchs. [ABSTRACT FROM AUTHOR]

The problem in using the existing biodegradable polymers for day‐to‐day commodity and specialty applications (non‐physiological) is the trade‐off between the degradability and physical properties of polymers. Therefore, the authors study the properties of polyester films made by solution blending of amorphous poly(d,l‐lactide) and semi‐crystalline poly(l,l‐lactide) (PLLA) with an aim to achieve a good balance of mechanical properties and degradability under environmental conditions. The degradation test using proteinase K enzyme shows faster degradation of blends in comparison to homopolymers by weight loss. Faster fragmentation of blends and fragments of lower masses in comparison to PLLA is also seen in immature compost with bulk degradation as the main mechanism of degradation. A detailed investigation shows increased crystallinity and the formation of crystalline stereo‐complex in fragmented samples that may limit degradation after a stage causing microplastics persisting for a longer period. Therefore, further degradation studies in compost for at least 8–10 weeks are recommended. Other environmental sinks, such as activated sludge water, fresh, and seawater, provide either extremely slow or no degradation excluding the use of such blends for applications intended for these sinks. In future, smart solutions are required to enhance the degradation of polylactide in different environmental sinks. [ABSTRACT FROM AUTHOR]

Anaerobic ammonium oxidation (anammox) is a biological nitrogen removal process with attractive prospects, such as no carbon addition, less aeration, lower greenhouse gas generation, and lower sludge production. However, it is difficult to maintain a stable anammox process since the anammox bacteria have a slow growth rate and high sensitivity to many factors. Therefore, it is very important to analyze and maintain the anammox activity as a process indicator for its successful operation. The conventional method for measuring the concentration of nitrogen compounds, such as ammonium, nitrite, or nitrogen gas is inconvenient during the reaction time for specific anammox activity (SAA) analysis, which can result in an inaccurately determined SAA due to the substrate loss and temperature change. In this study, a respirometer was utilized to analyze the SAA. The SAA values from a respirometer (rSAA) showed a similar pattern to the SAA values (mSAA) from the conventional method. All of the SAA analyses showed the highest value at 35 °C with a granule size of <1 mm. Statistical analysis showed no significant differences regardless of the analysis method, since the p-values for the t-test and Wilcoxon rank-sum test were >0.05. Therefore, the respirometer can be used as a simple and efficient tool for SAA analysis. Moreover, the operating maintenance and management of the anammox process can be improved due to the simple SAA analysis in the field. [ABSTRACT FROM AUTHOR]

In situ chemical oxidation (ISCO) is a popular remediation technique for hydrocarbon-contaminated soil and groundwater. A range of oxidising agents and activators are available for ISCO; however, selection is usually based on contaminant destruction which is time-consuming and impacted by sample heterogeneity based on 1–10 g sample contaminant analysis. In this paper, we demonstrate the use of an automated respirometer, measuring CO2 production, as a rapid and reliable approach for activator type and concentration selection. The approach is demonstrated based on tests in matrices of different types (loam soil and sand). In both matrices, CO2 production was significantly increased following sodium persulphate (SPS) oxidation with iron activation in a concentration-dependant manner. Alkaline activation led to no increased CO2 production compared to SPS addition without activation. The approach will provide greater confidence in treatability testing and reagent efficiency in ISCO projects. [ABSTRACT FROM AUTHOR]

The article presents the discussion on COVID-19 pandemic highlighting the global problem of air pollution through sustainable local and national policies for improving respiratory health and equity. Topics include air pollution exposure being associated with higher rates of hospitalizations and deaths from respiratory tract infections; and impairing the ability of macrophages to phagocytose reducing viral clearance and promoting infectivity.

Physiological features of species can determine the resilience and adaptation of organisms to the environment. Swimming capacity and metabolic traits are key factors for fish survival, mating and predator–prey interactions. Individuals of the same species can display high phenotypic variation often in response to varying environmental conditions. We investigated the effects of captive breeding conditions on swimming capacity, metabolic traits and morphology by comparing a captive population with a wild population of the endangered Spanish toothcarp (Aphanius iberus). We measured swimming capabilities and oxygen‐uptake rates simultaneously, the latter as a proxy for metabolic rate, using a swim tunnel respirometer. Results showed significant differences in standard metabolic rate (SMR), maximum metabolic rate (MMR) and absolute aerobic scope (AAS) between populations, as well as differences in morphological features between populations and sexes. In contrast, we did not find significant differences in critical swimming speed between populations or sexes. Differences in SMR between sexes were found in the captive population, and males showed nearly a twofold increase in SMR when compared with females. SMR, MMR and AAS were, on average, twofold lower for the captive population in comparison with the wild population. These differences in metabolic traits likely reflected captivity conditions, which were low food availability and the absence of predators, which in turn, may have influenced morphological traits, such as body and caudal peduncle shape and head size. At the same time, morphological traits also influenced metabolic traits of the populations. The lower SMR and MMR of captive individuals may be related to their deeper body shapes. Taken together, our results suggested that captive breeding conditions caused significant physiological and morphological changes in the endangered Spanish toothcarp. Reduced metabolic traits and changes in morphology may affect fitness‐related traits of the captive populations once reintroduced into the wild, thereby compromising conservation efforts. We therefore recommend to experimentally testing for the effects and consequences of captive breeding conditions before fish are released into the wild for successful conservation of them and other endangered species. [ABSTRACT FROM AUTHOR]

Background and Aims: Modern anesthetic practice utilizes low-flow anesthesia with evolving evidence on its pulmonary effects. Studies comparing measurement of vital capacity and inspiratory reserve volume using respirometer in both low-flow and high-flow anesthesia are sparse. We evaluated the effects of low-flow and high-flow anesthesia on postoperative pulmonary functions using respirometer. Material and Methods: This was a prospective randomized double blind study wherein One hundred and ten patients undergoing peripheral surgeries under general anesthesia were allocated into two groups Group I- Low-flow anesthesia with O2 + N2O + Sevoflurane (0.5L + 0.5L + 3.5%) and Group II- High-flow anesthesia with O2 + N2O + Sevoflurane (2L + 2L + 2%). The difference in vital capacity (VC), inspiratory reserve volume (IRV), and peak expiratory flow rates (PEFR) from the preoperative period were compared in both the groups postoperatively. Results: The difference in VC, IRV, and PEFR measured in both the groups between the preoperative and postoperative period were found to be similar and statistically insignificant (P - 0.173, 1.00 and 0.213 respectively). The difference in single breath count (SBC), breath holding time (BHT), and respiratory rates (RR) were also similar in both the groups (P – 0.101, 0.698, and 0.467) respectively. Conclusions: The pulmonary effects of low-flow anesthesia are comparable with the high-flow ones in patients undergoing elective surgeries under general anesthesia. [ABSTRACT FROM AUTHOR]

This study developed a portable, low‐cost field respirometer for measuring oxygen consumption rates of large‐bodied fishes. The respirometer performed well in laboratory tests and was used to measure the oxygen consumption rates (M˙O2) of bull sharks Carcharhinus leucas (mean: 249.21 ± 58.10 mg O2 kg−1 h−1 at 27.05°C). Interspecific comparisons and assessments of oxygen degradation curves indicated that the respirometer provided reliable measurements of M˙O2. This system presents a field‐based alternative to laboratory respirometers, opening opportunities for studies on species in remote localities, increasing the ability to validate physiological field studies. [ABSTRACT FROM AUTHOR]

Our aim was to develop a method to detect extramitochondrial Ca2+ movement and O2 fluxes simultaneously. Using High-Resolution FluoRespirometry, we also tested whether mitochondrial permeability transition pore (mPTP) inhibition or anoxia affects the mitochondrial Ca2+ flux. Ca2+ movement evoked by CaCl2 or anoxia was assessed with CaGreen-5N dye using Blue-Fluorescence-Sensor in isolated liver mitochondria, liver homogenates and duodenal biopsies. Exogenous CaCl2 (50 µM) resulted in an abrupt elevation in CaGreen-5N fluorescence followed by a decrease (Ca2+ uptake) with simultaneous elevation in O2 consumption in liver preparations. This was followed by a rapid increase in the fluorescence signal, reaching a higher intensity (Ca2+ efflux) than that of the initial CaCl2-induced elevation. Chelation of Ca2+ with EGTA completely abolished the fluorescence of the indicator. After pre-incubation with cyclosporin A, a marked delay in Ca2+ movement was observed, not only in isolated liver mitochondria, but also in tissue homogenates. In all samples, the transition to anoxia resulted in immediate increase in the level of extramitochondrial Ca2+. The results demonstrate that the CaGreen-5N method is suitable to monitor simultaneous O2 and Ca2+ fluxes, and the opening of mPTP in various biological samples. In this system the duration of stimulated Ca2+ fluxes may provide a novel parameter to evaluate the efficacy of mPTP blocker compounds. [ABSTRACT FROM AUTHOR]

In this study, swim‐tunnel respirometry was performed on Atlantic salmon Salmo salar post‐smolts in a 90 l respirometer on individuals and compared with groups or individuals of similar sizes tested in a 1905 l respirometer, to determine if differences between set‐ups and protocols exist. Standard metabolic rate (SMR) derived from the lowest oxygen uptake rate cycles over a 20 h period was statistically similar to SMR derived from back extrapolating to zero swim speed. However, maximum metabolic rate (MMR) estimates varied significantly between swimming at maximum speed, following an exhaustive chase protocol and during confinement stress. Most notably, the mean (±SE) MMR was 511 ± 15 mg O2 kg−1 h−1 in the swim test which was 52% higher compared with 337 ± 9 mg O2 kg−1 in the chase protocol, showing that the latter approach causes a substantial underestimation. Performing group respirometry in the larger swim tunnel provided statistically similar estimates of SMR and MMR as for individual fish tested in the smaller tunnel. While we hypothesised a larger swim section and swimming in groups would improve swimming performance, Ucrit was statistically similar between both set‐ups and statistically similar between swimming alone v. swimming in groups in the larger set‐up, suggesting that this species does not benefit hydrodynamically from swimming in a school in these conditions. Different methods and set‐ups have their own respective limitations and advantages depending on the questions being addressed, the time available, the number of replicates required and if supplementary samplings such as blood or gill tissues are needed. Hence, method choice should be carefully considered when planning experiments and when comparing previous studies. [ABSTRACT FROM AUTHOR]

Respirometry is a ubiquitous practice in experimental biology, but there is a lack of standard practices when analysing the resulting data, limiting transparency and reproducibility. As respirometry datasets become increasingly large and analytical approaches more complex, manipulating the data remains a challenge and often intractable with existing tools.Here we describe the respRR package, a collection of functions that implement a workflow‐based approach to automate the analysis and visualisation of respirometry data. The package can be used for closed, intermittent flow, flow‐through and open‐tank respirometry and uses well‐defined sets of rules to reliably and rapidly generate reproducible results.We demonstrate how respR uses novel computing methods such as rolling regressions and kernel density estimates to reliably detect maximum, minimum and most linear sections of the data, and critical oxygen tension, Pcrit.Although designed specifically with aquatic respirometry in mind, the object‐oriented approach of the package and the unit‐less nature of its analytical functions mean that parts of the package can easily be used to estimate linear relationships from a range of applications in many research disciplines. [ABSTRACT FROM AUTHOR]

This work proposes a miniaturized respiratory transducer array that utilizes the sharp temperature dependence of the resistivity characteristic of acrylate-based composites with a positive temperature coefficient. The proposed device employs an array configuration consisting of three sensing elements with the composites of different glass transition temperatures to achieve a wide operational temperature range. The temperature transient responses caused by different breathing conditions were clearly resolved by the device, and the corresponding respiration rates were easily extracted. The transducer array was characterized in a room temperature range from 23 °C to 29 °C. In addition, the device effectively detected the respiration rate up to a distance of 30 cm. It was also demonstrated that the device is capable of quantifying the breathing rate over a practical range of frequencies (from 0.1 Hz to 2 Hz). The respiration rates measured by the proposed device were also in good agreement with the results measured simultaneously by using a commercially available nasal pressure transducer. Comparison of the results demonstrated an excellent linear correlation (r = 0.953 and P < 0.001). The measured results suggest the feasibility of using this miniaturized device to monitor patients' respiration rates in clinical institutes and in other point-of-care applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Microalgae respiration increases due to photoinhibition and heat stress. • An empirical model was developed in order to describe this influence. • Five light-temperature models adopted from literature were compared. • Only one model described the complete range of experiments. • A previously developed model, upgraded with both models, was successfully validated. Abstract The influence of light and temperature on microalgae kinetics has been assessed extensively and many models have been developed. However, limited attention has been paid to the influence of light and temperature on microalgae respiration and growth under conditions inducing (strong) photoinhibition and no clear consensus has been made on which model to use. Based on experimental data collected using a combined respirometer-titrimeter, a previously developed microalgae model (Decostere et al., 2016b) was first extended with a respiration process (r = r min + δ μ). It was found that the dark respiration (r min) was depending on both light and temperature and increased at conditions inducing photoinhibition and heat stress. Furthermore, out of five models describing the influence of light and temperature on the microalgae growth rate, the model of Dermoun et al. (1992) was determined to be the best suited model. [ABSTRACT FROM AUTHOR]

Highlights • Sensor for measuring of respiratory gases (O 2 and CO 2) was developed. • Sensor was applied for real-time, non-invasive measurement of respiration rate. • Rapid measurement of respiration rate and RQ within 30 min. • Flushing and measuring of respiration rate under modified atmosphere was possible. • Developed respirometer was useful to measure respiration rate under in-situ condition. Abstract Monitoring respiration as rates of either O 2 consumption or CO 2 production is an important tool to optimise the design of packaging systems or to maintain optimal conditions inside storage systems for fruit and vegetables. Currently, respiration rates are mostly measured by gas chromatography or headspace gas analysers. Both these methods are manual and, for analysis, draw a considerable amount of gas from the system. Thus, they risk lowering the air pressure inside the storage and packaging volumes. In this study, a compact (free volume of 3.3 L) and modular respirometer based on a respiration measuring sphere (RMS88) was developed, which consisted of one O 2 (0–25%) and two CO 2 sensors (0–0.5% and 0–5%) for continuous real-time monitoring of gas concentrations and respiration rates of fresh produce. This system was tested under different conditions and respiration rates of strawberries were measured. At first, the system was tested without and with flushing of ambient air (every 6 h at 5 L/min) inside the respirometer at 10 °C. The system was further tested with strawberries stored under modified atmospheric conditions and flushing (every 5 h at 5 L/min) with stepwise reductions of O 2 from 21% to 16%, 8%, 4%, 2%, and 1% O 2 (balanced by nitrogen). Additionally, the developed system was tested under in-situ conditions for strawberries stored inside respirometer, kept in two separate controlled atmosphere (CA) metal chambers at 10 °C and 20 °C respectively. In addition, the respiratory quotient (RQ) of strawberries was calculated from the respective O 2 - and CO 2 -based respiration rates at all storage conditions. The modular respirometer proved to be a useful system for rapid, high accuracy and real-time measurement of respiration rates of fresh produce during time windows of several days. [ABSTRACT FROM AUTHOR]

Highlights • A three-electrode, Clark-type biosensor for mitochondrial respirometry in single oocytes and embryos is presented. • The sensor measured basal respiration, respiration associated with proton leak, and the maximal respiratory capacity. • The sensor can be used to analyze mitochondrial function in oocytes to determine the quality and viability of their development into embryos. Abstract This paper presents a disposable three-electrode, Clark-type biosensor suitable for mitochondrial respirometry in single oocytes and embryos. The biosensor was embedded in a PMMA (polymethyl methacrylate) micro-chamber to allow investigation of single oocytes/embryos immersed in up to 100 μl of respiration buffer. The micro-chamber was sealed to avoid oxygen exchange between the inside of the chamber and the atmosphere, while being maintained at a temperature of 38.5 °C to preserve cell viability. Using amperometry, the oxygen consumption of cells inside the micro-chamber was measured. The measurements from the sensor system revealed basal cell respiration supported by endogenous substrates, respiration associated with proton leak induced by inhibition of the adenosine triphosphate (ATP) synthase (complex V) with oligomycin, and the maximal non-coupled respiratory capacity revealed by carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) titration. Potential applications of this oxygen sensor system include evaluating effects of metabolic therapies on oocyte bioenergetics and monitoring mitochondrial function throughout oocyte maturation and blastocyst development to predict embryo viability to compliment assisted reproductive technologies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Extensive research effort has been devoted to the performance of the OSA system. Despite all studies focused on the assessment of observed sludge yield values, their explanations of the mechanisms causing sludge reduction remained highly speculative. RESULTS A laboratory‐scale OSA system fed with peptone mixture was operated together with a system consisting only of a sequencing batch reactor. The experimental program focused on the assessment of the nature and characteristics of all streams by calibrating an appropriate model by oxygen uptake rate profiles obtained under different conditions. Results indicated that the interchange stream contained a significant fraction of heterotrophic biomass. Therefore, interpretations of the microbial functions in the OSA/oxic reactor should account for active heterotrophic input through the interchange stream. As also justified by corresponding mass balance expressions, the OSA/oxic reactor sustained a substantially higher active biomass concentration as compared with the control reactor. In this way, the relative magnitude of the endogenous decay was significantly increased with respect to microbial growth and the observed experimental results totally accounting for the excess sludge reduction in the tested lab‐scale OSA system. CONCLUSION: The experimental results in this study provided conclusive proof that enhanced endogenous decay due to higher active biomass level sustained in the OSA/oxic reactor should be regarded as the major cause of excess sludge reduction in the OSA system. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article features several medical supplies including the Doboy CBS-D 750 M medical sealer from Syntegon Technology, the PicoScope 4000 A Series personal computer-based oscilloscopes from Pico Technology, and the Strathtox respirometer from Strathkelvin Instruments Ltd.

The article discusses the issues relating to the oxygen consumption measurements on air-breathers. It mentions the importance of low-cost electrochemical sensors such as the Clark polarographic O2 electrode and the zirconium sensor technology. It also mentions the need to prevent oxygen from entering the air-to-water respirometer via the air film during measurements.

Respirometric techniques are useful tools to evaluate bacterial activities in activated sludge processes due to their fast execution and the possibility to obtain several kinetic parameters from a single test. Using such techniques in microalgae-bacteria consortia treating wastewater could allow a better understanding of mutual interactions between the microbial populations as a function of environmental parameters. This work aims at developing and testing a novel experimental respirometric protocol to determine oxygen uptake rates and oxygen production rates by a microalgae-bacteria consortium. The defined protocol is characterized by alternating light/dark regimes and by dosing substrates/inhibitors to selectively activate/inactivate microalgal and bacterial metabolisms. The protocol was then applied on microalgal and bacterial consortia, which were grown on the liquid fraction of black water from biogas plants fed on agricultural and municipal waste sludge. Results elucidate the presence and activity of microalgae and nitrifying bacteria in the tested systems, suggesting that the respirometric tests could be included into monitoring procedures of photobioreactors/algal ponds. [ABSTRACT FROM AUTHOR]

This study reports on the metabolic rate of the blacktip shark Carcharhinus limbatus and the energetic costs of external tag attachment. Metabolic rates, swimming speed and tail‐beat (BT) frequency were measured in a static respirometer with untagged animals and animals equipped with a small data logger. Tagged sharks showed significantly higher routine oxygen consumption and lower swimming speeds than untagged animals, indicating that tagging significantly affected the swimming efficiency and energetic requirements in these small sharks, and that these effects must be accounted for when interpreting telemetry data from free‐ranging individuals. [ABSTRACT FROM AUTHOR]

Allylthiourea is a known specific inhibitor for ammonium oxidiser to suppress its oxygen uptake, and is commonly used for various kinds of batch respirometric tests to detect heterotrophic respiration in activated sludge. However, when high heterotrophs were present in the sample, it appeared the inhibitor was noticeably degraded and reached below the inhibition threshold after a couple of days, which resulted in overestimation of the heterotrophic respiration. The biological decomposition of the inhibitor was expressed with a Monod-type rate expression having a half-saturation coefficient of 980 mg-COD/L and maximum specific growth rate of 1.0 d-1. The developed kinetic model, including the growth and decay of the heterotrophs and nitrifiers, indicated that the ATU with about 90 mg-ATU/L which was initially dosed to the system would reach below the inhibition threshold of 1.0 mg-ATU/L after 10 days when 750 mg-COD/L of heterotrophs were present. From the kinetic model, an empirical formula to calculate a safe minimum ATU dose for the batch respirometric test was elaborated. The model also provided a modified experimental procedure to accurately estimate the initial heterotrophic biomass concentration in the sample and its specific decay rate based on IWA Activated Sludge Models. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the mechanisms, stoichiometry, and stability of 4-chlorophenol (4CP) biodegradation kinetics by phenol-acclimated activated sludge using open respirometry. While the removal of 4CP was higher than 98%, the removal of chemical oxygen demand (COD) ranged between 69 and 79% due to the accumulation of an intermediate metabolite. The value obtained from respirometric profiles for the stoichiometric ratio of O2 to 4CP (YO2/4CP) was 1.95 ± 0.04 mol of oxygen consumed per mol of 4CP removed. This YO2/4CP value reflected the action of the oxygenases responsible for the first steps of the aerobic oxidation of 4CP. The 4CP degradation activity decreased noticeably when successive pulses of 4CP were added to the respirometer. A mathematical model was developed to represent the aerobic biodegradation of 4CP. The fitted model adequately predicted the oxygen consumption rate, total phenols, and soluble COD concentrations as a function of time. The results presented could help to predict the dynamic of biodegradation of chlorophenols in a biological wastewater treatment system. [ABSTRACT FROM AUTHOR]

The evaluation of mitochondrial function provides the basis for the study of brain bioenergetics. However, analysis of brain mitochondrial respiration has been hindered by the low yield associated with mitochondria isolation procedures. Furthermore, isolating mitochondria or cells results in loss of the inherent complexity of the central nervous system. High-resolution respirometry (HRR), is a valuable tool to study mitochondrial function and has been used in diverse biological preparations ranging from isolated mitochondria to tissue homogenates and permeabilized tissue biopsies. Here we describe a novel methodology for evaluation of mitochondrial respiration using tissue preparations from the central nervous system, namely acute hippocampal slices from rodents, with HRR. By using acute intact hippocampal slices, tissue cytoarchitecture, intercellular communication and connectivity are preserved. Mitochondrial respiration was evaluated by using an adapted substrate-uncoupler-inhibitor titration (SUIT) protocol and the expected responses were observed. This methodology can be used to detect differences in mitochondrial function at the oxidative phosphorylation level and for studies with different brain oxidative substrates in physiological and neuropathological settings, by using a system that better represents the in vivo conditions than isolated mitochondria and/or cells. [ABSTRACT FROM AUTHOR]

Increasing evidence has shown that the energy use of ant colonies increases sublinearly with colony size so that large colonies consume less per capita energy than small colonies. It has been postulated that social environment (e.g., in the presence of queen and brood) is critical for the sublinear group energetics, and a few studies of ant workers isolated from queens and brood observed linear relationships between group energetics and size. In this paper,we hypothesize that the sublinear energetics arise from the heterogeneity of activity in ant groups, that is, large groups have relatively more inactive members than small groups. We further hypothesize that the energy use of ant worker groups that are allowed to move freely increases more slowly than the group size even if they are isolated from queen and brood. Previous studies only provided indirect evidence for these hypotheses due to technical difficulties. In this study, we applied the automated behavioral monitoring and respirometry simultaneously on isolated worker groups for long time periods, and analyzed the image with the state-of-the-art algorithms. Our results show that when activity was not confined, large groups had lower per capita energy use, a lower percentage of active members, and lower average walking speed than small groups; while locomotion was confined, however, the per capita energy use was a constant regardless of the group size. The quantitative analysis shows a direct link between variation in group energy use and the activity level of ant workers when isolated from queen and brood. [ABSTRACT FROM AUTHOR]

Fish swimming energetics are often measured in laboratory environments which attempt to minimize turbulence, though turbulent flows are common in the natural environment. To test whether the swimming energetics and kinematics of shiner perch, Cymatogaster aggregata (a labriform swimmer), were affected by turbulence, two flow conditions were constructed in a swim-tunnel respirometer. A low-turbulence flow was created using a common swim-tunnel respirometry setup with a flow straightener and finemesh grid to minimize velocity fluctuations. A high-turbulence flow condition was created by allowing large velocity fluctuations to persist without a flow straightener or fine grid. The two conditions were tested with particle image velocimetry to confirm significantly different turbulence properties throughout a range of mean flow speeds. Oxygen consumption rate of the swimming fish increased with swimming speed and pectoral fin beat frequency in both flow conditions. Higher turbulence also caused a greater positional variability in swimming individuals (versus low-turbulence flow) at medium and high speeds. Surprisingly, fish used less oxygen in high-turbulence compared with low-turbulence flow at medium and high swimming speeds. Simultaneous measurements of swimming kinematics indicated that these reductions in oxygen consumption could not be explained by specific known flow-adaptive behaviours such as Kaá rmaán gaiting or entraining. Therefore, fish in highturbulence flow may take advantage of the high variability in turbulent energy through time. These results suggest that swimming behaviour and energetics measured in the lab in straightened flow, typical of standard swimming respirometers, might differ from that of more turbulent, semi-natural flow conditions. [ABSTRACT FROM AUTHOR]

Introduction: The management of mechanically ventilated patients in the hyperbaric environment requires knowledge of how the physical properties of gases change under pressure and how this affects the operation of the ventilator. The primary objective of this study was to test the performance of the Dräger Oxylog 1000® ventilator in a hyperbaric environment. Methods: Each of two ventilators was connected to a mechanical test lung system with an in-built pressure gauge. We used a Wright's respirometer to measure the tidal volumes. The same ventilator settings were tested under varying environmental pressures from ambient (101.3 kPa) to 18 meters' sea water (284 kPa) in a multiplace hyperbaric chamber. Results: A decrease was found in tidal volume, decrease in airway pressure and increase in respiratory rate delivered by the Dräger Oxylog 1000 portable ventilator with increasing pressures to 284 kPa. Discussion: These findings can be explained by the operating principles of the Oxylog 1000, which is a time-controlled, constant-volume ventilator that functions as a flow chopper. Even between the two Oxylog 1000 ventilators tested there were different absolute changes in tidal volume, airway pressures and respiratory rates at various depths. Hence, the trend of changes in these variables is probably more important than absolute values. Conclusion: In summary, understanding the trend of changes in ventilator variables will allow clinicians to make appropriate corrections in ventilator settings and carefully monitor adequacy of ventilation to prevent adverse ventilator-associated events. The Dräger Oxylog 1000 portable ventilator is an adequate back-up ventilator for use with straight-forward, ventilatordependent patients undergoing hyperbaric treatment. [ABSTRACT FROM AUTHOR]

This review explores the conceptual and technological factors integral to the development of laboratory-based, automated real-time open-circuit mixing-chamber and breath-by-breath (B × B) gas-exchange systems, together with considerations of assumptions and limitations. Advances in sensor technology, signal analysis, and digital computation led to the emergence of these technologies in the mid-20th century, at a time when investigators were beginning to recognise the interpretational advantages of nonsteady-state physiological-system interrogation in understanding the aetiology of exercise (in)tolerance in health, sport, and disease. Key milestones include the 'Auchincloss' description of an off-line system to estimate alveolar O2 uptake B × B during exercise. This was followed by the first descriptions of real-time automated O2 uptake and CO2 output B × B measurement by Beaver and colleagues and by Linnarsson and Lindborg, and mixing-chamber measurement by Wilmore and colleagues. Challenges to both approaches soon emerged: e.g., the influence of mixing-chamber washout kinetics on mixed-expired gas concentration determination, and B × B alignment of gas-concentration signals with respired flow. The challenging algorithmic and technical refinements required for gas-exchange estimation at the alveolar level have also been extensively explored. In conclusion, while the technology (both hardware and software) underpinning real-time automated gas-exchange measurement has progressively advanced, there are still concerns regarding accuracy especially under the challenging conditions of changing metabolic rate. [ABSTRACT FROM AUTHOR]

In this paper we report on the metabolic rates and respiratory patterns measured from gregarious brown locusts, Locustana pardalina , collected from the Nama Karoo region in South Africa. All five instar hopper stages and adults were collected over a three year period when significant numbers of locust swarms were seen. Flow-through respirometry was used to measure the CO 2 emission from individual locusts from all the developmental stages and adults within a week of collection. Carbon dioxide emission scaled hypometrically with mass, 0.863 ± 0.026. Except in the 1st and 5th instar stage there was no difference in the mass specific rate of CO 2 emission ( V ̇ CO 2 < / ce : small - caps > ). These had significantly higher metabolic rates compared to the other stages which reflects their biology, with the 1st instar undergoing rapid growth and the 5th instar also undergoing rapid growth and development in preparation for becoming an adult. The 1st instars used a form of continuous gas exchange while all the other stages showed discontinuous gas exchange cycles. A clear burst phase and interburst periods could be seen. The 2nd and 3rd instars use mainly diffusion to expel CO 2 and so exhibited an open form of the burst phase. There was an increase in CO 2 volleys seen in the burst phase from the 4th instar stage onwards thus indicating an increased use of convection. There was no change in the duration or frequency of the discontinuous gas exchange cycles through the locust development or with body mass. [ABSTRACT FROM AUTHOR]

We explore a recent, innovative variation of closed-system respirometry for terrestrial organisms, whereby oxygen partial pressure (PO2) is repeatedly measured fluorometrically in a constant-volume chamber over multiple time points. We outline a protocol that aligns this technology with the broader literature on aerial respirometry, including the calculations required to accurately convert O2 depletion to metabolic rate (MR). We identify a series of assumptions and sources of error associated with this technique, including thresholds where O2 depletion becomes limiting, that impart errors to the calculation and interpretation of MR. Using these adjusted calculations, we found that the resting MR of five species of angiosperm seeds ranged from 0.011 to 0.640 ml g-1 h-1, consistent with published seed MR values. This innovative methodology greatly expands the lower size limit of terrestrial organisms that can be measured, and offers the potential for measuring MR changes over time as a result of physiological processes of the organism. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA), a well-known biodegradable and compostable polymer, was used in this study as a model system to determine if the addition of nanoclays affects its biodegradation in simulated composting conditions and whether the nanoclays impact the microbial population in a compost environment. Three different nanoclays were studied due to their different surface characteristics but similar chemistry: organo-modified montmorillonite (OMMT), Halloysite nanotubes (HNT), and Laponite® RD (LRD). Additionally, the organo-modifier of MMT, methyl, tallow, bis-2-hydroxyethyl, quaternary ammonium (QAC), was studied. PLA and PLA bio-nanocomposite (BNC) films were produced, characterized, and used for biodegradation evaluation with an in-house built direct measurement respirometer (DMR) following the analysis of evolved CO2 approach. A biofilm formation essay and scanning electron microscopy were used to evaluate microbial attachment on the surface of PLA and BNCs. The results obtained from four different biodegradation tests with PLA and its BNCs showed a significantly higher mineralization of the films containing nanoclay in comparison to the pristine PLA during the first three to four weeks of testing, mainly attributed to the reduction in the PLA lag time. The effect of the nanoclays on the initial molecular weight during processing played a crucial role in the evolution of CO2. PLA-LRD5 had the greatest microbial attachment on the surface as confirmed by the biofilm test and the SEM micrographs, while PLA-QAC0.4 had the lowest biofilm formation that may be attributed to the inhibitory effect also found during the biodegradation test when the QAC was tested by itself. [ABSTRACT FROM AUTHOR]

The main objective of this study is to demonstrate the importance of mixing conditions as a source of inconsistencies between half-saturation indices in comparable systems (e.g. conventional activated sludge, membrane bioreactor) when operated at different conditions or different scales. As proof-of-principle, an exemplary system consisting of the second vessel of a hybrid respirometer has been studied. The system has been modeled both using an integrated computational fluid dynamics (CFD)-biokinetic model (assumed to represent the physical system) and a tanks-in-series, completely stirred tank reactor biokinetic model (representing the applied model). The results show that different mixing conditions cause deviations in the half-saturation indices calculated when matching the applied model to the physical system performance. Additionally, sensor location has been shown to impact the calculation of half-saturation indices in the respirometric system. This will only become more pronounced at larger scales. Thus, mixing conditions clearly affect operation and design of wastewater treatment reactors operated at low substrate concentrations. Both operation and design can be improved with the development and application of integrated CFD-biokinetic or compartmental models. [ABSTRACT FROM AUTHOR]

Our goals were: (i) to determine whether sublethal concentrations of water-borne ammonia would prevent the formation of a dominance hierarchy, or alter its structure, in groups of 4 juvenile trout; (ii) to investigate the behavioral and physiological responses of individuals of different social rank exposed to a concentration of ammonia that still allowed hierarchy formation. Social hierarchies were created by using a technique in which a food delivery system that created competition also served to isolate individual fish for respirometry. Groups of 4 fish were exposed to elevated ammonia (NH 4 HCO 3 ) 12 h before first feeding; aggression was recorded by video camera during morning feedings. Experimental ammonia concentrations were 700, 1200 and 1500 μmol L −1 at pH 7.3, 12 °C (9.8, 16.8, and 21.0 mg L −1 as total ammonia-N, or 0.0515, 0.0884, and 0.1105 mg L −1 as NH 3 -N). Aggression was severely reduced by 1200 and abolished by 1500 μmol L −1 total ammonia, such that hierarchies did not form. However, groups exposed to 700 μmol L −1 total ammonia still formed stable hierarchies but displayed lower levels of aggression in comparison to control hierarchies. Exposure continued for 11 days. Physiological parameters were recorded on day 5 (end of period 1) and day 10 (end of period 2), while feeding and plasma cortisol were measured on day 11. In control hierarchies, dominant (rank 1) trout generally exhibited higher growth rates, greater increases in condition factor, higher food consumption, and lower cortisol levels than did fish of ranks 2, 3, and 4. In comparison to controls, the 700 μmol L −1 total ammonia hierarchies generally displayed lower growth, lower condition factor increases, lower O 2 consumption, lower cortisol levels, but similar feeding patterns, with smaller physiological differences amongst ranks during period 1. Effects attenuated during period 2, as aggression and physiological measures returned towards control levels, indicating both behavioral and physiological acclimation to ammonia. These disturbances in social behavior and associated physiology occurred at an ammonia concentration in the range of regulatory significance and relevance to aquaculture. [ABSTRACT FROM AUTHOR]

For over two centuries, scientists have measured gas exchange in animals and humans and linked this to energy expenditure of the body. The aim of this review is to provide a comprehensive overview of open-circuit diluted flow indirect calorimetry and to help researchers to make the optimal choice for a certain system and its application. A historical perspective shows that 'open circuit diluted flow' is a technique first used in the 19th century and applicable today for room calorimeters, ventilated hood systems, and facemasks. Room calorimeters are a classic example of an open-circuit diluted flow system. The broadly applied ventilated hood calorimeters follow the same principle and can be classified as a derivative of these room calorimeters. The basic principle is that the subject breathes freely in a passing airflow that is fully captured and analyzed. Oxygen and CO2 concentrations are measured in inlet ambient air and captured outlet air. The airflow, which is adapted depending on the application (e.g., rest versus exercise), is measured. For a room indirect calorimeter, the dilution in the large room volume is also taken into account, and this is the most complex application of this type of calorimeter. Validity of the systems can be tested by alcohol burns, gas infusions and by performing repeated measurements on subjects. Using the latter, the smallest CV (%) was found for repeated VO2max tests (1.2%) with an SD of approximately 1 kJ min-1. The smallest SD was found for sleeping metabolic rate (0.11 kJ min-1) with a CV (%) of 2.4%. [ABSTRACT FROM AUTHOR]

Microrespirometry is a recently developed method that combines classical respirometry and microreactor systems, for the characterization of microbial cultures. This method, which allows multiple simultaneous replicates from a single low-volume biomass sample, can improve and simplify the model calibration exercise by providing more and better experimental data. To follow up on the interest in microrespirometry, two model wastewater treatment processes were set up and used for model calibration: an aerobic degradation of 4-chlorophenol by acclimated sludge, and a synthetic wastewater treatment by activated sludge, which were well described by a Haldane model and a modified ASM3 model, respectively. For each process, the model parameters were estimated by model fitting, minimizing the objective function for each replicate independently, and minimizing the objective function for all replicates simultaneously (multiresponse approach). Parameter confidence intervals were determined for all parameter estimates, and the impacts of measurement errors, number of replicates, and parameter correlation were assessed. It was observed that the multiresponse approach presents several advantages, including single-step parameter estimation, independent of the number of replicates, and determination of confidence intervals that include the main sources of uncertainty. It was concluded that microrespirometry is a high-throughput and convenient method for model calibration. [ABSTRACT FROM AUTHOR]

For millennia, humans have focused their attention on the breath to develop mindfulness, but finding a scientific way to harness mindful breathing has proven elusive. Existing attempts to objectively measure and feedback on mindfulness have relied on specialist external hardware including electroencephalograms or respirometers that have been impractical for the majority of people learning to meditate. Consequently, training in the key skill of breath-awareness has lacked practical objective measures and guidance to enhance training. Here, we provide a brief technology report on an invention, The MindfulBreather r that addresses these issues. The technology is available to download embedded in a smartphone app that targets, measures and feedbacks on mindfulness of breathing in realtime to enhance training. The current article outlines only the technological concept with future studies quantifying efficacy, validity and reliability to be reported elsewhere. The MindfulBreather works by generating Motion Guided Mindfulness through interacting gyroscopic and touchscreen sensors in a three phase process: Mindfulness Induction (Phase I) gives standardized instruction to users to place their smartphone on their abdomen, breathe mindfully and to tap only at the peak of their inhalation. The smartphone's gyroscope detects periodic tilts during breathing to generate sinusoidal waveforms. Waveform-tap patterns are analyzed to determine whether the user is mindfully tapping only at the correct phase of the breathing cycle, indicating psychobiological synchronization. Mindfulness Maintenance (Phase II) provides reinforcing pleasant feedback sounds each time a breath is mindfully tapped at the right time, and the App records a mindful breath. Lastly, data-driven Insights are fed back to the user (Phase III), including the number of mindful breaths tapped and breathing rate reductions associated with parasympathetic engagement during meditation. The new MGM technology is then evaluated and contrasted with traditional mindfulness approaches and a novel Psychobiological Synchronization Model is proposed. In summary, unlike existing technology, the MindfulBreather requires no external hardware and repurposes regular smartphones to deliver app-embedded Motion-Guided Mindfulness. Technological applications include reducing mindwandering and down-regulation of the brain's default mode through enhanced mindful awareness. By objectively harnessing breath awareness, The MindfulBreather aims to realize the ancient human endeavor of mindfulness for the 21st century. [ABSTRACT FROM AUTHOR]

The NDHA model comprehensively describes nitrous oxide (N 2 O) producing pathways by both autotrophic ammonium oxidizing and heterotrophic bacteria. The model was calibrated via a set of targeted extant respirometric assays using enriched nitrifying biomass from a lab-scale reactor. Biomass response to ammonium, hydroxylamine, nitrite and N 2 O additions under aerobic and anaerobic conditions were tracked with continuous measurement of dissolved oxygen (DO) and N 2 O. The sequential addition of substrate pulses allowed the isolation of oxygen-consuming processes. The parameters to be estimated were determined by the information content of the datasets using identifiability analysis. Dynamic DO profiles were used to calibrate five parameters corresponding to endogenous, nitrite oxidation and ammonium oxidation processes. The subsequent N 2 O calibration was not significantly affected by the uncertainty propagated from the DO calibration because of the high accuracy of the estimates. Five parameters describing the individual contribution of three biological N 2 O pathways were estimated accurately (variance/mean < 10% for all estimated parameters). The NDHA model response was evaluated with statistical metrics (F-test, autocorrelation function). The 95% confidence intervals of DO and N 2 O predictions based on the uncertainty obtained during calibration are studied for the first time. The measured data fall within the 95% confidence interval of the predictions, indicating a good model description. Overall, accurate parameter estimation and identifiability analysis of ammonium removal significantly decreases the uncertainty propagated to N 2 O production, which is expected to benefit N 2 O model discrimination studies and reliable full scale applications. [ABSTRACT FROM AUTHOR]

The objective of this study is the evaluation of the performance of a large-scale respirometer (LSR) of 17.7 L in the determination of the methane generation rate constant (k) values. To achieve this objective, a comparison between anaerobic (GB21) and LSR tests was conducted. The data were modeled using a linear function, and the resulting correlation coefficient (R²) of the linear regression is 0.91. This result shows that despite the aerobic conditions, the biodegradability values that were obtained from the LSR test produced results that are similar to those from the GB21 test. In this respect, the LSR test can be an indicator of the anaerobic biodegradability for landfill waste. In addition, the results show the high repeatability of the tests with an average coefficient of variance (CV) that is lower than 10%; furthermore, the CV for the LSR is lower than that of the GB21, which indicates that the LSR-test method could provide a better representation of waste samples. Therefore, the LSR method allows for both the prediction of the long-term biodegradation potential in a shorter length of time and the reduction of the sampling errors that are caused by the heterogeneity of waste samples. The k values are 0.156 y-1 and 0.127 y-1 for the cumulative biogas production (GB21) and the cumulative oxygen uptake for the LSR, respectively. [ABSTRACT FROM AUTHOR]

This study evaluated odor generated during the first stage of the composting process in a dynamic respirometer using different raw materials such as the organic fraction of municipal solid waste (OFMSW), a mixture of this organic fraction with orange peel waste (OFMSW-OPW), sewage sludge with bulking agent (SL) and a mixture of strawberry extrudate, fish waste, sewage sludge and bulking agent (SFWSL). The combination of near infrared reflectance (NIR) spectroscopy and chemometric analysis is proposed to correlate the chemical composition and the operational variables of each raw material to odor generated during the composting process. The operational variables temperature, dynamic respirometric index (DRI), airflow (Q), odor concentration (OC) and odor emission rate (OER) were monitored. Adequate linear correlations were obtained between temperature and DRI for each compostable substrate within a confidence interval of 10% and 30%. Operational variables were statistically analyzed by principal component analysis with 87% of total variance explained and from which the substrates were clearly grouped. Near infrared reflectance spectroscopy provided the chemical composition of each raw material, and was found to be an advantageous technique to predict the relationship between odor emissions and absorption bands. Odor emissions were also predicted from the operational variables by multivariate regression, with temperature and DRI being the most influential variables. [ABSTRACT FROM AUTHOR]

Background: Shewanella baltica KB30 was isolated from seawater collected in Kandalaksha Bay, White Sea (Russia). This strain is known for its ability to grow on a pool of different substrates, including carbohydrates, carboxylic and amino acids, and lipids. However, no data are available on its metabolic efficiency in relation to the use of different carbon sources typologies. This work represents the first attempt to characterize S. baltica by its heterotrophic kinetic performance. Results: Growth and substrate consumption, during the biodegradation of sodium acetate, glucose, tween 80 and peptone, were analyzed through a respirometric method. To find the model best fitting the experimental data and to obtain the kinetic parameters, the equations of Monod, Moser, Contois and Tessier were applied. The kinetic behavior of S. baltica was fitted to Monod model for sodium acetate and tween 80, while it was adjusted to Contois model for glucose and peptone. In this regard, peptone was consumed faster than the other substrates, as indicated by the highest values of substrate degradation rate, which exceeded 60 mg O2 L-1h-1. Conclusions: Proteolytic metabolism was favored than lipidic and glucidic metabolism, which could contribute much more to mineralization and recycling of proteins than lipids and carbohydrates. [ABSTRACT FROM AUTHOR]

Methyl ester sulfonate (MES) is an anionic surfactant derived from palm oil through sulfonation of fatty acid methyl esters. Due to limited ecotoxicological data on MES, this study was initiated to evaluate the ecotoxicological properties of MES and its impact to the environment. The respirometric method (OECD 301F) was used to monitor the biodegradation of various homologues of MES over 28 days. The algae growth inhibition test (OECD 201) was conducted to assess the effects of palm-based MES towards green algae by exposing exponentially-growing cultures of Pseudokirchneriella subcapitata ( P. subcapitata) to five concentrations of MES with maximum concentrations of 100 mg/L. Results showed all MES samples were readily biodegradable, where the biodegradability of each homologue surpassed 60% within 28 days. It was also observed that the longer the carbon chain length of MES, the solubility and the biodegradability rate decreased. The ecotoxicity of C12 and C14 MES towards P. subcapitata after 72 h of experiment showed no inhibition of algae growth in C12 MES while, the growth of algae decreased as the concentration of C14 MES increases. The EC value for C14 MES and C16 MES towards green algae was >100 and >10 mg/L, respectively. It can be concluded that C12 and C14 MES were practically non-toxic towards P. subcapitata and the toxicity increased with an increase in chain length of the surfactant (EC value decreases). Therefore homologues of palm-based MES are not expected to cause environmental concern due to their biodegradability and low toxicity in the aquatic environment. [ABSTRACT FROM AUTHOR]

The standard metabolic rates of similarly sized juvenile diploid and triploid brook charr were estimated by using intermittent-flow respirometry to measure oxygen uptake over a 10-day fasting period. Initial oxygen uptake rates did not differ between ploidies, but the rate of decline was slower in triploids, resulting in higher final oxygen uptake rates and, therefore, higher estimated standard metabolic rates. Based on other studies that have shown no effect of triploidy on maximum metabolic rate, this implies reduced aerobic scope in triploids. [ABSTRACT FROM AUTHOR]

The article presents a study for discussing the effects of acoustic telemetry transmitters on gill ventilation rate and haematocrit levels of round goby Neogobius melanostomus. Topics include impact of invasive fish species on ecosystems and sustainable fisheries, preservation of round gobies in the National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund, and flushing of aerated ambient water for maintaining normoxic conditions inside the respirometer.

Mitochondria are the powerhouse of animal cells. They produce through oxidative phosphorylation more than 90% of the cellular energy (ATP) required for organism's growth, reproduction, and maintenance. Hence, information on mitochondrial function is expected to bring important insights in animal ecology and evolution. Unfortunately, the invasiveness of the procedures required to measure mitochondrial function (e.g. sampling of liver or muscles) has limited its study in wild vertebrate populations so far. Here, we capitalize on the fact that bird red blood cells (RBCs) possess functional mitochondria to describe a minimally invasive approach to study mitochondrial function, using blood samples., In the king penguin, we present a protocol, using a high-resolution respirometry system and specific agonists and antagonists enabling the assessment of mitochondrial function in RBCs. We evaluated the inter-assay repeatability of our measures of mitochondrial function, and tested the influence of sample storage and bird handling time on these measures. We also compared measures of mitochondrial function in RBCs and in the pectoral muscle obtained from the same individuals., Mitochondria from RBCs showed the expected responses to mitochondrial agonists and antagonists, and therefore the protocol presented allows computing effective measures of mitochondrial function. The different measures of RBC mitochondrial function were significantly repeatable, were not affected by the handling time of the bird prior to blood sampling (i.e. stress response), and only minimally affected by the storage time of the sample at 4 °C up to 24 h. Most notably, we showed that mitochondrial parameters measured in RBCs moderately correlated to those measured in the pectoral muscle., This study sheds light on the use of RBCs in birds as a valuable and minimally invasive source of information on mitochondrial function. This approach opens new opportunities to study mitochondrial function in free-living animals and could bring knowledge gains in ecology and evolution. Fish, amphibians and reptiles also possess mitochondria in their RBCs, and the approach presented here could also be applicable to these taxa. [ABSTRACT FROM AUTHOR]