Range Of Water Temperatures Research Articles

The Role of Water Temperature Modelling in the Development of a Release Strategy for Cyprinid Herpesvirus 3 (CyHV-3) for Common Carp Control in Southeastern Australia

The common carp (Cyprinus carpio) is an invasive species in the rivers and waterways of southeastern Australia, and it has been implicated in the serious decline of many native fish species. Over the past 50 years, various control options have been explored, and to date, these have been ineffective or cost-prohibitive. Most recently, cyprinid herpesvirus 3 (CyHV-3) has been proposed as a biocontrol agent because of its high specificity and mortality rate. However, the virus is known to be only effective in a permissive water temperature range of approximately 16–28 °C. To define when this occurs, we undertook a hydrological reconstruction of five diverse river catchments (>130,000 km2) of southeastern Australia over three decades. This confirmed, in the studied areas, that while water temperatures are permissive from spring through to autumn, the time of year that this starts and ends is highly variable, interannually, and with strong latitudinal and altitudinal gradients between and within catchments. The results show that the virus should be effective with respect to water temperature throughout the water temperature range that carp occur in most of southeastern Australia. However, detailed water temperature estimation would still be required to determine the exact week of the start of release in any given catchment. Referring to observations in wild carp populations, we point out the limitation of developing a “release strategy” based solely on water temperature modelling and the need to incorporate fish biology and ecology into this planning.

In vitro bioassay methods to test the efficacy of thermal treatment on the salmon louse, Lepeophtheirus salmonis

Salmon lice, Lepeophtheirus salmonis (Krøyer, 1837), are ectoparasites of the Atlantic salmon, their presence on the fish host is often linked to increased economic losses to the aquaculture industry in the northern hemisphere. Initial attempts to control parasite numbers primarily involved chemical treatment methods, however, there has been a gradual shift towards what are considered more environmentally friendly methods including thermal treatment. This method has been in use for several years; however, few studies have been conducted on its effect on the salmon lice. This study aimed to determine the effect of 2 min exposure to increased water temperature on the copepodid and pre-adult II stages from seven L. salmonis populations and develop in vitro bioassay methods for on-site testing. Seven geographically distinct populations (population A-G) originating from northern-, mid-, and southern-Norway were included in this study. Treatment temperatures were calculated as Δ°T, the difference between the maintenance temperature (12 °C) and treatment temperature. For each population, parasites were exposed for 2 min to a range of water temperatures (Δ°T, 18 ‐ 28°C), after which they were returned to 12 °C seawater. Parasites were observed and classified as unaffected/affected at two timepoints, immediately following exposure and 24 h post-treatment. Differences between populations were observed in the copepodid stage immediately following exposure. All copepodids in populations B and E were immobilised at Δ20°C, compared to population C with unaffected copepodids present at Δ26°C. However, 24 h later all populations exhibited normal behaviour at Δ22°C. Population A and E were all affected at Δ25°C, while unaffected copepodids were observed in population C (16.3%) at Δ26°C. The pre-adult II stage showed a similar trend when observed immediately following exposure, all parasites affected in population A and E at Δ19°C, whereas population C had 20% unaffected at Δ22°C. At the 24 h observation parasites had generally recovered from exposure to Δ23°C with the lowest being population F (33%) and the highest being population A (83.3%). This study illustrated that all stages of L. salmonis had an immediate reaction to thermal treatment, yet the majority recovered over time. Differences in baseline sensitivity were observed between populations, to ensure high treatment efficacy, routine in vitro bioassays to determine whether thermal treatment should be implemented.

Linking flow and upper thermal limits of freshwater mussels to inform environmental flow benchmarks

Abstract Freshwater ecosystems are experiencing shifts in the natural range and variation of water temperatures due to anthropogenic activity, and these shifts can negatively affect survival, growth, and reproduction of aquatic species. Among the groups most affected are freshwater mussels of the family Unionidae. Knowledge of sublethal and lethal effects on mussels from changes in water temperature are largely unknown, especially for species from arid and semi‐arid regions such as the south‐western U.S.A. This limits the ability to assess, forecast, and adaptively manage this threat for those species and to understand how temperature influences population performance and community structure. To determine the effects of elevated water temperature on mussels from the south‐western U.S.A., we evaluated the upper thermal tolerances of adults of three species (Amblema plicata, Cyclonaias necki, and Fusconaia mitchelli) from the Guadalupe River. Mussels were acclimated to 27°C and then tested across a range of experimental temperatures (30–39°C) in standard acute (96‐hr) and chronic (10‐day) laboratory tests. The acute and chronic thresholds identified in thermal tolerance testing were then related to in situ water temperature and flows using a uniform continuous above‐threshold analysis, which evaluates the duration and frequency of continuous events above a specified temperature threshold. Median lethal temperature in 96‐hr tests averaged 36.4°C and ranged from 33.7 to 37.5°C, while the chronic 10‐day tests averaged 35.9°C and ranged from 32.4 to 37.5°C. Thermal tolerances of F. mitchelli were significantly lower than both A. plicata and C. necki, and the uniform continuous above‐threshold analysis showed that temperature affecting 5% of the population thresholds were exceeded for F. mitchelli in the Guadalupe River at both acute (96‐hr) and chronic (10‐day) values (30.5 and 28.4°C, respectively). Findings from this study indicate that freshwater mussels from the arid and semi‐arid regions of the south‐west U.S.A. are already at risk from rising environmental temperatures and altered hydrology. However, by incorporating laboratory thermal tolerance estimates with in situ temperature and discharge data, we provide a range of hydrologic thresholds to inform environmental flow recommendations and potentially mitigate thermal stress occurring during periods of low flow. In addition, this method can be readily adapted to other arid regions to guide flow recommendations or assess whether flow standards are sufficient to protect freshwater mussel populations during severe droughts and low flow periods.

Performance enhancement and heat and mass transfer characteristics of direct evaporative building free cooling using corrugated cellulose papers

In hot and dry climatic zones, direct evaporative cooling (DEC) system is used as an economical and efficient alternative to traditional air conditioning systems. The present paper concerns comprehensive experimental investigations and analysis of heat and mass transfer characteristics and thermal performance parameters of a bee-hive construction of corrugated-cellulose papers as a new cooling pad material. The performance parameters used to evaluate the effectiveness of the cooling pad materials are the outlet air temperature and relative humidity, pressure drop, humidifier effectiveness, rate of the evaporated water, sensible cooling capacity, specific cooling capacity (SCC), coefficient of performance (COP), specific water consumption (SWC), and Nusselt and Sherwood numbers. The cooling pad performance was investigated for a wide range of air and water temperatures and flow rates and pad thicknesses. The results show the enhancements of heat and mass transfer coefficients and the performance parameters with rising air temperature and water flow rate to humidifier. High values of the performance parameters (hc = 45 W/m2oC and hm = 0.23 m/s, εhum = 0.85 and COP = 170) are obtained compared to the traditional pad materials. Experimental correlations for the evaporative cooler performance parameters in terms of air and water temperatures and flow rates pad thicknesses are presented.

Abundance of Pelagia noctiluca early life stages in the western Mediterranean Sea scales with surface chlorophyll

Pelagia noctiluca is the most successful and well-studied jellyfish in the Mediterranean Sea. This species tolerates a wide range of water temperatures and succeeds in low to medium food regimes, but factors driving its distribution and population dynamics remain poorly understood. Here we applied a multiscale analytical approach using survey data and a physical-biochemical coupled model to assess how environmental factors affect the 3-dimensional distribution and seasonal abundance of P. noctiluca early life stages. The surveys took place after the spring bloom, when warm water favors fecundity and growth, but food shortage limits the reproductive investment and early survival. We found that most early life stages of P. noctiluca remained above the shallow thermocline and upper mixed layer where temperature is warm. Their spatial distribution was positively correlated with surface chlorophyll concentration, and over 90% of the variation in interannual abundance was explained by basin-scale productivity in June. Warmer water during winter and spring seasons coupled with protracted spring blooms increase the population of P. noctiluca, and this explains the trend of increasing outbreaks observed in the western Mediterranean Sea over the past decades.

Parasite transmission in aquatic ecosystems under temperature change: effects of host activity and elimination of parasite larvae by filter‐feeders

A moderate increase in temperature is likely to enhance the impact of parasites on aquatic ecosystems. Thus, under higher temperatures, poikilothermic animals (e.g. fish) increase their activity, which can result in a more frequent encounter with parasites and higher infection risk. However, temperature increase may also trigger counteracting processes in ambient communities decreasing the risk of parasitic infections. For instance, the removal of free‐living stages of parasites by filter‐feeding organisms can increase with temperature and potentially mitigate the disease risk in ecosystems under temperature shift. We examined whether an enhanced parasite transmission under higher temperatures can be compensated by the increased removal of parasitic larvae by filter‐feeders. In addition, our study aimed to reveal the behavioral mechanism underlying the more successful transmission of the parasite at higher temperatures. We studied experimentally how temperature, behavior of fish hosts (rainbow trout), and presence of filter‐feeding mussels in the environment influence the infection success of trematode larvae (Diplostomum pseudospathaceum cercariae). We found that heating increased while the presence of filter‐feeding mussels in the environment decreased infection intensities in fish. However, the effect of mussel's presence was constant within the tested range of water temperatures (15–23°C), which suggests that it cannot compensate for the observed increased transmission of parasites with temperature increase. Fish activity before the exposure to parasites was positively related to the host's vulnerability to infection. However, fish activity only weakly correlated with temperature, therefore, it is unlikely to be the only factor influencing the infection success under warmer conditions. In general, we showed that the elimination of trematode larvae by filter‐feeders is unlikely to deter the potential effects of temperature increase on host–parasite interactions in temperate freshwater ecosystems.

Effects of temperature and hypoxia on respiration, photorespiration, and photosynthesis of seagrass leaves from contrasting temperature regimes

Abstract In near-future climate change scenarios, elevated ocean temperatures with higher and more frequent peaks are anticipated than at present. Moreover, increased eutrophication and higher primary and secondary productivity will affect the oxygen levels of shallow-water coastal ecosystems, creating hypoxic conditions that can be experienced regularly, especially in dense vegetated systems. These climate-related events may impose detrimental effects on the primary productivity of seagrass. To evaluate such effects, this study combined gas exchange measurements with pulse amplitude-modulated fluorometry to assess the impact of short-time exposure to a range of water temperatures at ambient and low-oxygen levels on mitochondrial respiration, chlorophyll fluorescence (based on the Fv/F0 ratio), photosynthetic oxygen evolution, and photorespiration in leaf segments of the temperate seagrass Zostera marina and the tropical seagrass Thalassia hemprichii. We found that mitochondrial respiration in both Z. marina and T. hemprichii increased with higher temperatures up to 40°C and that low O2 caused significantly reduced respiration rates, particularly in T. hemprichii. Elevated water temperature had a clear negative effect on the Fv/F0 of both seagrass species, indicating damage or inactivation of the photosynthetic apparatus, even when light is not present. Moreover, damage to the photosynthetic apparatus was observed as an effect of elevated temperature combined with low O2 during darkness, resulting in subsequent lower photosynthesis in light. Photorespiration was present, but not promoted by increased temperature alone and will thus not further contribute to productivity losses during warmer events (when not carbon limited). This study demonstrates the negative impact of hypoxic stress and elevated temperatures on seagrass productivity, which may influence the overall health of seagrass plants as well as oxygen and carbon fluxes of shallow-water coastal ecosystems in warmer climate scenarios.

ECG-based Identity Validation during Bathing in Different Water Temperature*.

This paper proposes a novel identity validation method using ECG signal measured during bathing at 5 different bathtub water temperature ranges, that are 37 ±0.5 °C, 38±0.5 °C, 39±0.5 °C, 40±0.5 °C and 41±0.5 °C, respectively. The experiment includes 5 male and 5 female subjects, each subject collects 2 ECG recordings at each bathtub water temperature range, one day one recording, 10 ECG recordings are collected from each subject, each ECG recording is 18 minutes long, the sampling rate is 200 Hz. During the data processing stage, we perform spectrum analysis, baseline wandering removal, 50 Hz electromagnetic interference removal, signal smoothing, R peaks detection, and QRS complex segmentation. During the classification stage, we perform identity validation using long short-term memory (LSTM) classification network. 5 classification models are trained based on different bathtub water temperature ranges and the cross-validation method is used. Preliminary validation results show that different bathtub water temperature has an important impact on the identity validation. In order to precisely and quickly perform identity validation at different bathtub water temperature ranges, the final classification model is trained based on the samples from 5 different bathtub water temperature ranges. The highest and average identity validation accuracies are 98.43% and 97.68%, respectively.

Temperature-Related Responses of an Invasive Mussel and 2 Unionid Mussels to Elevated Carbon Dioxide.

Zebra mussels (Dreissena polymorpha) have exacerbated the decline of native freshwater mussels (order Unionida) in North America since their arrival in the 1980s. Options for controlling invasive mussels, particularly in unionid mussel habitats, are limited. Previously, carbon dioxide (CO2) showed selective toxicity for zebra mussels, relative to unionids, when applied in cool water (12 °C). We first determined 96‐h lethal concentrations of CO2 at 5 and 20 °C to zebra mussels and responses of juvenile plain pocketbook (Lampsilis cardium). Next, we compared the time to lethality for zebra mussels at 5, 12, and 20 °C during exposure to partial pressure of CO2 (PCO2) values of 110 to 120 atm (1 atm = 101.325 kPa) and responses of juvenile plain pocketbook and fragile papershell (Leptodea fragilis). We found efficacious CO2 treatment regimens at each temperature that were minimally lethal to unionids. At 5 °C, plain pocketbook survived 96‐h exposure to the highest PCO2 treatment (139 atm). At 20 °C, the 96‐h lethal concentration to 10% of animals (LC10) for plain pocketbook (173 atm PCO2, 95% CI 147–198 atm) was higher than the LC99 for zebra mussels (118 atm PCO2, 95% CI 109–127 atm). Lethal time to 99% mortality (LT99) of zebra mussels in 110 to 120 atm PCO2 ranged from 100 h at 20 °C to 300 h at 5 °C. Mean survival of both plain pocketbook and fragile papershell juveniles exceeded 85% in LT99 CO2 treatments at all temperatures. Short‐term infusion of 100 to 200 atm PCO2 at a range of water temperatures could reduce biofouling by zebra mussels with limited adverse effects on unionid mussels. Environ Toxicol Chem 2020;39:1546–1557. Published 2020. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

External factors that regulate movement in the marine rotifer Brachionus plicatilis

There are two types of movement pattern in the Brachionidae (rotifers), swimming and attachment, although the factors that induce a shift between them have not been adequately clarified. This study investigated the effects of five external factors—food limitation, temperature, salinity, predator, and un-ionized ammonia—on movement in females of the euryhaline rotifer Brachionus plicatilis sensu stricto. Rotifers under periodic starvation showed increased swimming frequency (percentage of swimming rotifers) to about 50% on feeding compared to controls under continuous feeding (21%). Starved rotifers were further exposed to the following conditions for 2 days: a range of water temperature (15–25 °C), salinity (17–34 practical salinity units), a predator (or other rotifers)-conditioned medium, and un-ionized ammonia (NH3-N; 5–20 mg/l). Neither temperature nor predator conditioning significantly affected rotifer swimming frequency. However, rotifers transferred to a higher salinity or to a rotifer-conditioned medium ceased to exhibit swimming. All the tested ammonia levels caused vigorous swimming of rotifers during the initial experimental period. The results indicate that swimming in female rotifers can be classified as (1) an escape behavior induced by environmental stress, and (2) a response to higher viability under certain favorable environmental conditions.

Evidence of diverse movement strategies and habitat use by white sharks, Carcharodon carcharias, off southern Australia

Large endothermic pelagic sharks are highly migratory and use habitats spanning a broad range of coastal, neritic and oceanic areas. This study aimed to resolve the current lack of information on the movements and habitat use of white sharks, Carcharodon carcharias, between shelf, slope and oceanic areas located off southwestern Australia. Movement behaviours, spatial distribution patterns and vertical habitat use of juvenile, sub-adult and adult white sharks ranging in size from 1.9 to 5.7 m total length were examined using 43 satellite tags deployed over 15 years. Pop-up satellite archival tags and satellite-linked radio tags collected 3663 days and > 109,900 km of tracking data over periods of up to 381 days. We demonstrated sex-based differences in movement and distribution patterns of male (21) and female (19) white sharks. Female dispersal was broader and extended further offshore than males, which largely remained in neritic and gulf habitats. Female white sharks experienced a narrower range of water temperatures (F = 9.0–19.0 °C; M = 10.4–24.8 °C). Despite these subtle differences, both sexes showed an affinity to the Neptune Island Group and the shelf slope canyons of the eastern Great Australian Bight, which are productive and oceanographically complex regions that support known prey of white sharks. This study highlighted that the southern-western Australian population of white sharks use off-shelf habitat to a greater extent than previously identified. Findings have potential implications for: ecological risk assessments of fisheries that operate in these offshore habitats and for monitoring and managing marine protected areas.

3-D Printed Swastika-Shaped Ultrabroadband Water-Based Microwave Absorber

In this letter, a swastika-shaped ultrabroadband metamaterials absorber is proposed. The designed absorber can be fabricated with the polylactic acid by 3-D printing, and packaged after filling with water. The absorber can achieve greater than 90% absorption in the frequency band of 9.3–49.0 GHz, with a relative bandwidth of 136%, which has been well demonstrated in the microwave experiment. Moreover, it also performs well at wide angles of incidence and the absorption efficiency has almost no obvious changes over the water temperature range of 0 °C–100 °C. The absorber proposed in this letter benefits from ultrawideband absorption, low cost and environment-friendly materials, it can be applied in the fields of electromagnetic (EM) stealth and EM energy harvesting.

Identifikasi Kesesuaian Kawasan Wisata Panatai Saleo Kecamatan Waigeo Selatan Kampung Saonek Kabupaten Raja Ammpat

This study aims 1) to find out how the Ecological land condition of the Tourism area in Saleo Beach, South Waigeo District, Saonek Village, Raja Ampat Regency. 2) to find out the shape of the tourist area in Saleo Beach, South Waigeo District, Saonek Village, Raja Ampat Regency. Data collection is done by interviewing techniques and documentation. The analysis technique used is qualitative descriptive analysis. The results showed: Physical condition of Saleo Beach The physical condition at Saleo beach is the highest tide of 1.58cm. And the average tidal range obtained is 0.95 m. The average wave height ranges from 0.08m-0.43m. with a current speed of 0.2m / s. With 100% water brightness with a depth of 350 cm and water temperature range of 27 -29 C, the depth of the Saleo coast 0-25 m. slope drought has a flat condition. So that the value of the physical parameters of Saleo beach as much as 85.71% is in the range obtained from 90 -100% into the category of very feasible (S). infrastructure and accessibility. In this case it is still lacking the comfort conditions for visitors who come and even though there are places to stay and some places to relax or rest on the beach. Thus the feasibility of Saleo Beach is included in the quite feasible category with the feasibility value.

RELATIONSHIP OF ORGANIC MATERIAL WITH ABUNDANCE OF TOXIC BENTHIC DINOFLAGELLATA ON SEDIMENT IN WATERS OF TELUK BAKAU VILLAGE BINTAN REGENCY, RIAU ISLAND PROVINCE

Dinoflagellata was included in one of microalgae groups which are on waters of the sea and the river, it can be found on detritus floats, sediments, and also swim freely. This research done on May – June 2018 at waters of the mangrove bay village, Bintan Regency, Riau Island Province. The aims of this research was to know relationship between organic material concentration toward abundance of toxic benthic dinoflagellata on sediment. In addition, to analyzed organic material concentratin and amount of abundance of toxic benthic dinoflagellata on sediment in waters of Teluk Bakau. The method used was survey method which is the location of sampling is done by pursosive sampling. Measurement of water quality sampling done at any point, the surface water temperature range 31-33oC, 28-31 ‰ salinity, pH 8-9 and the current speed from 0.045 to 0.051 m / det.Perairan predominantly sandy gravel sediments, making an average of organic materials ditemukn at each station is 0.027%, 0.043%, 0.033%, 0.024%. The result of this research found 3 genus of toxic dinoflagellata, which are Prorocentrum, Gambierdiscus, and Ostreopsis. Poisonous dinoflagelatta can produced a several types of toxic that found the sea. The highest of abundance found at station 2 on 75,615 sel/m2 and the lowest found at station 1 on 35,176 sel/m2. the results of simple linear regression analysis the relationship between the concentration of organic material with the abundance of dinoflagellates has a positive relationship with the regression equation y = 32,913 + 556,13x

Morphometric Relationships of the Global Invader Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) from Papapouli Lagoon, NW Aegean Sea, Greece. with Notes on Its Ecological Preferences

Callinectes sapidus is native to the Atlantic coasts of the Americas. In the Mediterranean, it appeared around 1949 and though that it is established in East Mediterranean waters, relevant studies are limited. The aim of the present study is to report quantitative and qualitative data on the blue crab’s biology and ecology in its non-native range, that are indispensable for management purposes. Papapouli Lagoon is in Thermaikos Gulf and is ecologically impacted by the blue crabs. Fyke nets with a 20 mm mesh opening were soaked for 12 to 14 h during each survey. Abiotic environmental parameters were obtained. The length–weight relationships were expressed by the equation W = aLb. The species’ ecological preferences at Papapouli Lagoon were assessed with PERMANOVA analysis, using the abiotic parameters as factors. Student’s t-tests were used to assess the differences between sexes. The sex ratio of the blue crab’s population was assessed by a Chi-square (χ2) analysis. The sex ratio was found to be 1.28:1, in favour of males. The most dominant group size of male blue crabs was the 61–70 mm of CL and 130–139 mm of CW. Also, the dominant size group of female blue crabs was 60–69 mm of CL and 120–129 mm CW. The maximum abundance of blue crabs was recorded at a salinity range from 24‰ to 25‰ and the water temperature range was from 26 to 28 °C.

Acceleration-triggered animal-borne videos show a dominance of fish in the diet of female northern elephant seals.

Knowledge of the diet of marine mammals is fundamental to understanding their role in marine ecosystems and response to environmental change. Recently, animal-borne video cameras have revealed the diet of marine mammals that make short foraging trips. However, novel approaches that allocate video time to target prey capture events is required to obtain diet information for species that make long foraging trips over great distances. We combined satellite telemetry and depth recorders with newly developed date-/time-, depth- and acceleration-triggered animal-borne video cameras to examine the diet of female northern elephant seals during their foraging migrations across the eastern North Pacific. We obtained 48.2 h of underwater video, from cameras mounted on the head (n=12) and jaw (n=3) of seals. Fish dominated the diet (78% of 697 prey items recorded) across all foraging locations (range: 37-55°N, 122-152°W), diving depths (range: 238-1167 m) and water temperatures (range: 3.2-7.4°C), while squid comprised only 7% of the diet. Identified prey included fish such as myctophids, Merluccius sp. and Icosteus aenigmaticus, and squid such as Histioteuthis sp., Octopoteuthis sp. and Taningia danae Our results corroborate fatty acid analysis, which also found that fish are more important in the diet, and are in contrast to stomach content analyses that found cephalopods to be the most important component of the diet. Our work shows that in situ video observation is a useful method for studying the at-sea diet of long-ranging marine predators.

Photosynthesis and growth of Ulva ohnoi and Ulva pertusa (Ulvophyceae) under high light and high temperature conditions, and implications for green tide in Japan

SUMMARYThe macroalga Ulva ohnoi constitutes a considerable fraction of green tides in coastal areas of Japan, but little is known about the physiological characteristics of this species. To investigate the environmental factors that promote the formation of green tides, we tested the responses of U. ohnoi and another common Japanese species, Ulva pertusa, to various levels of irradiance at different water temperatures. Because the two species are morphologically similar, we identified them using the PCR‐restriction fragment length polymorphism method. Under laboratory conditions, we evaluated the photosynthetic, dark respiration, and relative growth rate at a range of water temperatures (5 to 35°C) and photosynthetically active radiation (0 to 1000 μmol photons m−2 s−1). The maximum gross photosynthetic rate of U. ohnoi was larger than that of U. pertusa. The dark respiration rates revealed no significant differences among the species and temperature conditions. At 500 μmol photons m−2 s−1, the relative growth rate of U. ohnoi was larger than that of U. pertusa in higher temperature and the difference was the largest at 20°C. The estimated compensation irradiance and estimated saturation irradiance of U. ohnoi and U. pertusa ranged from 0.709 to 5.510 and 40.530 to 58.674 μmol photons m−2 s−1, which were lower than those in other intertidal green macroalgae, from 6 to 11 and 50 to 82 μmol photons m−2 s−1, respectively. Thus, U. ohnoi which exists as free‐floating near the water surface and accumulating inside the green tide can survive extensively in the water column of the intertidal zone, furthermore, the species can maintain rapid growth in this situation. Therefore, as a result of this study, it is suggested that the ecological success of U. ohnoi in shallow waters such as the tidal flats, estuarine, and coasts of the inner bay in comparison with U. pertusa.

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

AbstractNylon 6 and 6,6 literature data are collected over a wide range of water concentrations and temperatures (0 ≤ [W]0 ≤ 40.8 wt%, 200 ≤ T ≤300 °C) and used to fit parameters in an updated batch reactor model. The resulting copolymerization model uses side reactions to account for the complex influence of water on kinetics and reaction equilibria. The proposed parameter estimates result in a significant improvement in the fit to the data, corresponding to a 73% reduction in the weighted‐least‐squares objective function compared to when the parameters of Arai et al. are used. Copolymerization simulations are conducted at industrially relevant conditions, shedding light on the complex influence of water and on the potential to include waste nylon 6 cyclic dimer in the feedstock. The model and parameter estimates will be helpful in future models of nylon 6/6,6 copolymerization in continuous reactor systems.

Predicting Corrosion rate in Chilled HVAC Pipe Network: Coupon vs Linear Polarisation Resistance method

Research has been undertaken to predict corrosion rate of conveyance pipes used in a Heating Ventilation and Air Conditioning (HVAC) system. This work focuses on comparing the performance of a conventional corrosion predicting technique known as the “coupon method” versus a relatively modern technique called Linear Polarisation Resistance (LPR). An experimental study has been conducted by designing a relatively modern rig that was representative of a typical HVAC system. It was found that both the coupon method and the LPR probe predicted similar corrosion rates with a difference of 8.3% which is insignificant in practical applications. Four highly important in-situ scenarios were simulated for a water temperature range of 12–32 °C, and it was found that an LPR probe with corroded electrodes over-predicted corrosion rate by 20% compared to a clean LPR probe. Also, a probe in use for 2 months over-predicted corrosion by 44% which is a significant error. A pipe network dosed with inhibitor was observed to reduce the rate of corrosion by 50% and 25% for water temperature of 12 °C and 32 °C respectively. It was also determined that one degree (oC) increase in water temperature will increase the corrosion rate by 3.5% on average. It has been identified that both coupon and LPR probes give similar results though both have limitations and continuous monitoring of corrosion is the way to insure a low maintenance HVAC pipe network.

Vertical heterogeneities of cyanobacteria and microcystin concentrations in lakes using a seasonal In situ monitoring station

A high frequency, high resolution, seasonal research station was deployed to quantify a wide range of local meteorological conditions, water temperature, and water chemistry, including phycocyanin, in two different eutrophic stratified Minnesota lakes. The monitoring effort was coupled with discrete weekly sampling measuring nutrients, cyanobacteria composition, and microcystin concentrations. Our objective was to describe the vertical and seasonal distributions of cyanobacteria biovolume (BV) and microcystin concentrations (MC) using physical lake variables. Two types of BV distributions were observed above the thermocline upward in the water column. The first distribution depicted BV uniformly distributed over the diurnal surface layer (hSL), and the second BV distribution displayed local BV maxima. A quantitative relationship was developed to determine the anticipation of observing a uniform distribution as a function of the surface layer Reynolds number (ReSL), the dimensionless ratio of inertial to viscous forces. The uniform distribution was observed systematically for ReSL > 50,000. MC was observed to accumulate above the thermocline and have a vertical distribution similar to BV, thus depending on ReSL. This is important for directing sampling efforts, because it narrows the range of BV and MC heterogeneity above the thermocline, and suggests a vertical sampling protocol to detect potential maxima and compute representative depth-average concentrations. We explored the temporal variability of the MC to BV ratio, spatially averaged in the epilimnion (MCep/BVep). The maximum MCep/BVep occurred before the maximum BVep and specifically, during the onset of significant biomass growth in both lakes. This observation is notable because the maximum MCep occurs before the visual signs of enhanced cyanobacterial accrual are less recognizable to the public and to monitoring efforts. Our findings could have important implications for predicting MC distribution and guiding monitoring strategies for quantifying MC concentrations in small stratified lakes.