Differences In Water Temperature Research Articles

Does Method of Field Preparation Affect Survival and Growth of Juvenile Chinook Salmon in Agricultural Floodplains?

ABSTRACTThere is growing interest to integrate conservation initiatives into agricultural practices using a reconciliation ecology framework. In California's Central Valley, one approach to improving crucial nursery habitat for threatened and endangered fish species is by re‐creating floodplain habitats through the inundation of agricultural fields during the non‐growing season. We conducted a series of field experiments in agricultural floodplains (winter‐flooded rice fields that historically were natural floodplains) to examine whether different field preparation methods enhanced growth and survival of floodplain‐dependent fish species. Approximately 8000 juvenile fall‐run Chinook Salmon (Oncorhynchus tshawytscha) were reared for at least 28 days on eight, 0.2 hectares (ha) experimental fields. Each experimental field represented one of four treatments (two replicates per treatment): addition of large wood, addition of in‐field canals, addition of both large wood and in‐field canals, and control. Controls fields received no additional field preparations beyond standard post‐growing practices: that is chopping rice into stubble, baling, and removing excess rice straw, and discing the field with a single pass by plowing rice straw into the ground to promote decomposition. We found no significant difference in water temperature, fish growth or fish survival among habitat treatments. Across treatments, survival ranged from 50.1% to 78.3% and averaged 65.75% (+/− 7.89% SE). These findings suggest agricultural floodplains require no additional modifications to promote fish growth and survival. Results illustrate the benefits of integrating working landscapes with conservation initiatives, as this approach creates more accessible and beneficial habitat for native fish species.

Study on the inverse problem of thin slab continuous casting mold based on fluid-solid coupled heat transfer

The thin slab continuous casting (TSCC) process employs a funnel-shaped mold, introducing increased complexity to both the structure and heat transfer of the mold, as well as the cooling water channels. This paper presents a three-dimensional fluid-solid coupled model for calculating the heat flux in a thin slab mold. The model is calculated and validated based on temperature data collected from molds and cooling water in the plant. The results show that the deviations of the wide face average heat flux and cooling water temperature difference from the measured values are 3.49 % and 1.1 %, respectively, demonstrating good agreement. Moreover, the influence of the thin slab mold geometry on heat transfer is explored. The heat flux values calculated in this model are approximately 13 % lower than those in the simplified model in the upper part of the original funnel area, and 2–7% lower in the lower part. Therefore, this model reflects the heat flux's three-dimensional characteristics of the funnel-shaped mold, offering a novel approach to calculating the heat flux of the thin slab mold.

Relationships between morphological factors and heat extraction from the upper arm using liquid cooling garment

Astronauts wear liquid perfused garments inside their outer spacesuits for regulating body temperature. The present study explored relationships between local heat production from the upper arm and body morphology while wearing liquid perfused sleeve. Heat extraction from the upper arm of 19 subjects (8 males and 11 females) during three different exercise modes (running at 6–8 km∙h−1, cycling at 40–55 W, and arm ergometer at 10–20 W) and rest has been investigated. The total body fat (27.5 ± 7.2%), body mass index (24.4 ± 2.7 kg·m−2), arm surface area (589 ± 90 cm2), and arm volume (1300 ± 300 mL) were considered as covariates. Subjects wore a liquid perfused sleeve over the upper arm (left) with the water inlet temperature of 24.0 ± 0.3 °C and the heat extraction was calculated using the water flow rate and temperature differences. Heat extraction from the upper arm showed no significant differences among the three exercises. During cycling, there was a negative relationship between heat extraction and total body fat (r = − 0.527, P < 0.05). Heat extraction was more related to the arm volume (P < 0.05) than the surface area of the upper arm, which was significant only for the male group in the cycling mode. For the female group, heat extraction was related to upper arm temperature in the cycling and arm exercise modes (for both exercises P < 0.05). These results can be applied to improve liquid cooling garments for astronauts, considering their body morphology and sex.

Integration of the WRF model and IoT sensors to develop an early cold snap warning system for inland fishponds

The cold weather-related economic losses in the aquaculture and fisheries industries are enormous and will only increase due to future climate change. Advancements in weather forecasting have increased the accuracy of predicting environmental factors like air temperature, solar radiation, and wind speed. However, the water temperature of fishponds, which affects the lives of fish, cannot be accurately predicted. As a result, fishermen are unable to implement early disaster mitigation and avoidance measures effectively. In this study, we developed an early warning system for extreme temperature events in fishponds by using a weather forecasting model in combination with local observations from a customized sensor placed in a pond. This system could provide water temperature forecasts with up to 120 h of lead time. A fishpond and multiple events were selected to assess the performance. Compared to the actual observations, the predicted water temperature difference had a root mean square error of <2 °C for up to 72 h of lead time. Furthermore, due to limited computational resources for weather forecasting models, the water temperature and depth data collected by the sensor improved the accuracy of temperature prediction specific to each pond. The results have confirmed that the integrated method can effectively predict the water temperature of farmed fishponds and assist fishermen in implementing precautionary measures in time.

Seasonal Dynamics of the Silica-Scaled Chrysophytes as Potential Markers of Climate Change in Natural Model: Deep Cold Lake–Shallow Warmer Reservoir

In the context of global climate changes, it is important to assess the sustainability perspective of aquatic ecosystems based on marker organisms. In this work, we analyzed seasonal dynamics of silica-scaled chrysophytes in freshwater communicating environments which have considerable differences in water temperature between two ecosystems: the deep and cold oligotrophic Lake Baikal versus the shallower and warmer downstream Irkutsk Reservoir having mesotrophic features. During three seasons of the open water period of 2023, 38 species of silica-scaled chrysophytes were observed at 17 stations using scanning and transmission microscopy. The distribution of silica-scaled chrysophytes was shown to correlate with the water temperature. The greatest species richness was observed in the spring season in a large bay of the Irkutsk Reservoir (23 species), the smallest in the cold spring waters of Southern Baikal (up to 7 species). Widespread species living in Southern Baikal continued to grow in warmer waters of the reservoir. Using the example of silica-scaled chrysophytes, the stability of the high-latitudinal freshwater ecosystems affected by climate change is discussed. Continuous increment of the water temperature can lead to an increased abundance of widespread species and the displacement of psychrophilic species, affecting the overall biodiversity in such ecosystems.

Characteristics of the fish food supply of the Uglich reservoir

The work on assessing the feed base of the Uglich Reservoir was carried out within the framework of annual monitoring studies by the Branch for Freshwater Fisheries of the Federal State Budgetary Scientific Institution “VNIRO” (VNIIPRH). Samples were taken in July 2021 and 2022 on three sections. During the year, 10 samples of zooplankton and benthic invertebrate communities were collected and processed. The purpose of the study is to evaluate the fish food supply of the Uglich Reservoir according to the indicators of zooplankton and benthic invertebrate communities in the period 2021–2022. The tasks of the study: to determine the number and biomass of zooplankton of the Uglich Reservoir in 2021–2022; to determine the number and biomass of benthic invertebrate communities of the Uglich Reservoir in 2021–2022. The Uglich Reservoir belongs to the Upper Volga cascade of hydro nodes. Located in the territory of two regions and having a length of more than a hundred kilometers, it has differences in water temperature and oxygen content in the water by reaches. Oxygen conditions in 2021 in the bottom layers, and in 2022 — both in the surface and in the bottom horizons, were unfavorable: deviations from the water quality standard were observed. The studies showed that the productivity of the Uglich Reservoir also varies by reaches. The maximum indicators of zooplankton development were observed in the channel part of the Upper reach of the reservoir. During the observation period (with incomplete determination), 21 taxa of planktonic organisms were recorded, including: Rotifera — 5, Cladocera — 12, Copepoda — 3 and Bivalvia — 1 species. In the composition of the plankton fauna, Cladocera dominated in number and biomass. The benthic invertebrate communities of the Uglich Reservoir is mainly represented by oligochaetes, chironomid larvae and bivalve molluscs. By the magnitude of the summer biomass of zooplankton and benthic invertebrate communities, in accordance with the generally accepted classification of Pidgayko (1968), the Uglich Reservoir in 2021 can be assessed as a high-feed reservoir, and in 2022 — as a medium-feed reservoir.

Response of wild aquatic insect communities to thermal variation through comparative landscape transcriptomics.

Fluctuations in temperature are recognized as a potent driver of selection pressure, fostering genomic variations that are crucial for the adaptation and survival of organisms under selection. Notably, water temperature is a pivotal factor influencing aquatic organism persistence. By comprehending how aquatic organisms respond to shifts in water temperature, we can understand their potential physiological adaptations to environmental change in one or multiple species. This, in turn, contributes to the formulation of biologically relevant guidelines for the landscape scale transcriptome profile of organisms in lotic systems. Here, we investigated the distinct responses of seven stream stonefly species, collected from four geographical regions across Japan, to variations in temperature, including atmospheric and water temperatures. We achieved this by assessing the differences in gene expression through RNA-sequencing within individual species and exploring the patterns of community-genes among different species. We identified 735 genes that exhibited differential expressions across the temperature gradient. Remarkably, the community displayed expression levels differences of respiration and metabolic genes. Additionally, the diversity in molecular functions appeared to be linked to spatial variation, with water temperature differences potentially contributing to the overall functional diversity of genes. We found 22 community-genes with consistent expression patterns among species in response to water temperature variations. These genes related to respiration, metabolism and development exhibited a clear gradient providing robust evidence of divergent adaptive responses to water temperature. Our findings underscore the differential adaptation of stonefly species to local environmental conditions, suggesting that shared responses in gene expression may occur across multiple species under similar environmental conditions. This study emphasizes the significance of considering various species when assessing the impacts of environmental changes on aquatic insect communities and understanding potential mechanisms to cope with such changes.

Evaluation of the impacts of turbidity on Gilgel-Gibe I reservoir storage, Omo-Gibe River Basin, Ethiopia

Quantity and quality of the water held in the reservoir fluctuates due to turbidity alterations. The influence of turbidity on the amount of the water held in a reservoir was described explicitly in this research. This study aimed to evaluate turbidity's impact on the Gilgel-Gibe I reservoir water. The samples were obtained by longitudinally stratifying the reservoir water throughout its course. Ten burrowed pools wrapped in transparent white plastic were used to retain water, for detection of the association between turbidity and surface water temperature, and to demonstrate the vertical variation in water temperature. The pan evaporation rate was measured using two Class A pans placed in the field to indicate the disparity in the amount of water evaporated from reservoir owing to reservoir turbidity variation. SPSS and MS Excel spreadsheet softwares were used to analyze the data. According to the results of this study, turbidity and water temperature have a significant direct relationship that is positive at 9:00 and 13:00 and negative at 17:00 observation hours. From the top layer of pool water to the bottom layer, the water temperature decreased vertically. Intensity of the light rays absorbed and scattered alters with turbidity variation and significant amounts of light rays was absorbed and scattered in the most turbid water. The reported water temperature differences between the top and bottom layers at 13:00 observation hour were 9.78 °C and 1.53 °C, for the most and least turbid pool water, respectively. Turbidity directly affects reservoir water by increasing both the water temperature and evaporation rates. Among all turbid-water samples, substantial quantity of water evaporated from the most turbid-water. For the most and least turbid water samples, the volume difference of the evaporated water from the reservoir was approximately 65.812 m3. According to these findings, if the reservoir water turbidity increases, the amount of water held in the reservoir significantly reduced due to substantial water loss.

Spatial and Temporal Variability of Ocean Thermal Energy Resource of the Pacific Islands

A lack of natural resources drives the oil dependency in Pacific Island Countries and Territories (PICTs), hampering energy security and imposing high electricity tariffs in the region. Nevertheless, the Western Equatorial Pacific is known for its large Sea Surface Temperature (SST) and deep-sea water (DSW) temperature difference favorable for harvesting thermal energy. In this study, we selected 18 PICTs in the western Equatorial Pacific to estimate Annual Energy Production (AEP) for a 1 MW class Ocean Thermal Energy Conversion (OTEC) plant. We combined the DSW temperature from the mean in situ Argo profiles and 1 km resolution satellite SST data to estimate the thermal energy resource resolving the fine features of the island coastline. Furthermore, the twenty-year-long SST dataset was used to analyze the SST variability. The analysis showed that Equatorial islands and Southern islands have the highest inter-annual variability due to El Nino Southern Oscillation (ENSO). The power density varied from 0.26 to 0.32 W/m2 among the islands, with the lowest values found for the southernmost islands near the South Equatorial Countercurrent. Islands within the South Equatorial Current, Equatorial Undercurrent, and North Equatorial Countercurrent showed the highest values for both power density and gross power. Considering a 1 MW class OTEC plant, Annual Energy Production (AEP) in 2022 varied from 7 GWh to 8 GWh, with relatively low variability among islands near the Equator and in low latitudes. Considering the three variables, AEP, SST variability, and distance from the shore, Nauru is a potential candidate for OTEC, with a net power of 1.14 MW within 1 km from the shore.

Temperature effects on ion migration and energy consumption during brackish water electrodialysis desalination

Electrodialysis (ED) is a well-established brackish water (BW) desalination technology based on the selective electro-transfer mechanism of ions for meeting freshwater demands in scarce water regions. While the influence laws of water temperature difference caused by changing seasons on the performance of BWED need to be clarified further. This study examined the effect of temperature on the desalination efficiency and energy consumption of BWED by controlling the water temperature with a constant temperature tank. Results showed that higher temperature significantly increased the current density and salt flux of BWED, but also caused a decrease and then an increase in energy consumption. The apparent activation energy of BWED system in low temperature range is about 40 % higher than that in high temperature range, indicating that higher temperature is contributed to reduce the ion transport resistance. While higher temperature increased ion diffusivity and membrane pore size, with a corresponding rise in LCD of ∼0.41 mA/cm2 and an increase in desalination ratio of ∼7.75 % for increment of every 10 °C, thus enhanced reverse salt diffusion. The running parameters of BWED system should be regularly regulated with the seasonal temperature based on the trade-off between desalination efficiency and energy consumption to ensure an efficient operation.

Experimental investigation of high-temperature heating in open-loop air cycle heat pump system utilizing compressed gas waste energy recovery

Recycling waste energy from compressed gases has consistently been a focal point in the field of energy conservation. This paper presents a novel open-loop air cycle heat pump system designed to recover waste energy from compressed gases. The system maintains stable operation and provide hot water above 80 °C even under extreme ambient temperatures (below −30 °C), thereby catering to diverse heating needs across a wide temperature spectrum. Experimental results show that, when the ambient temperature varies from 10 °C to −20 °C, the heating capacity and water temperature difference between inlet and outlet only decrease by 4.82% and 4.99% respectively, suggesting negligible impact. However, when water flow rate varies from 4 m3/h to 10 m3/h, the heating capacity marginally increases by 3.35% while the water temperature difference between inlet and outlet significantly decreases by 141.95%. Continuous increase of inlet water temperature Tw, in at 0.40 °C·min−1 results in an initial 10% decrease of heating capacity, following which the system automatically adjusts to another stable operational state of around 50 kW heating capacity. This transition has minimal effect on the water temperature difference between inlet and outlet and temperature rise rate of outlet water temperature. The expansion work recovery efficiency of turbine-compressor coupled module is approximately 90%.

The Effects of Algal Blooms on Oxygen Levels in Lakes Babati and Eyasi, Tanzania

Globally aquatic ecosystems are reportedly overwhelmed by algal blooms due to excessive deposition of nutrients which ultimately cause hypoxia, leading to massive fish death. This study aimed at assessing the relationship between algae contents and dissolved oxygen (DO) in Lake Babati which is threatened by anthropogenic activities, whereas Lake Eyasi was used as a control. Algae contents (chlorophyll a), DO and surface water temperature were measured using standard methods. Results revealed that the mean algae content was significantly higher (4.47±0.88 mg/L) in Lake Babati than in Lake Eyasi (1.6±0.45 mg/L) (P &lt; 0.05) and was beyond the standard permissible levels for domestic water supply and healthy ecosystem. Conversely, DO was significantly lower in Lake Babati than in Lake Eyasi (P &lt; 0.05). There was no significant difference in water temperature in the two lakes (P &gt; 0.05). Furthermore, there was an inverse relationship between algae content and DO in Lakes Eyasi and Babati (r = -0.88 and r = -0.30, respectively) suggesting that algal bloom is partly responsible for lowering DO. Responsible authorities are advised to enforce management policies and regulations to control unsustainable activities around these lakes that contribute to nutrient loading resulting into overgrowth of algae.

Zooplankton community structure and diel migration patterns vary over hours, days, and years in the pelagic and littoral zone of a eutrophic reservoir

Abstract Zooplankton play an integral role as indicators of water quality in freshwater ecosystems, but exhibit substantial variability in their density and community composition over space and time. This variability in zooplankton community structure may be driven by multiple factors, including taxon-specific migration behavior in response to environmental conditions. Many studies have highlighted substantial variability in zooplankton communities across spatial and temporal scales, but the relative importance of space vs. time in structuring zooplankton community dynamics is less understood. In this study, we quantified spatial (a littoral vs. a pelagic site) and temporal (hours to years) variability in zooplankton community structure in a eutrophic reservoir in southwestern Virginia, USA. We found that zooplankton community structure was more variable among sampling dates over 3 years than among sites or hours of the day, which was associated with differences in water temperature, chlorophyll a, and nutrient concentrations. Additionally, we observed high variability in zooplankton migration behavior, though a slightly greater magnitude of DHM vs. DVM during each sampling date, likely due to changing environmental conditions. Ultimately, our work underscores the need to continually integrate spatial and temporal monitoring to understand patterns of zooplankton community structure and behavior in freshwater ecosystems.

Study of metal–organic framework (MOF)/water pairs for adsorption heat transformer applications

Metal-organic framework (MOF), an advanced category of porous coordination polymers, has recently gained prominence as a novel class of adsorbent materials, captivating the attention of researchers worldwide engaged in diverse applications related to adsorption. An adsorption heat lifter or adsorption heat transformer (AdHT) plays a crucial role in elevating the temperature of a waste heat source. This is achieved by harnessing the adsorption enthalpy or isosteric heat of adsorption. The system performance of the AdHT system is affected by the working pairs, which leads to a possible application for MOF/water working pairs in such a system. In this study, 2-tank and 3-tank systems are invoked to investigate and compare the coefficient of performances (COPs) of three MOFs: MOF–801, aluminum fumarate, and MIL–100(Fe) paired with water while considering an atmospheric temperature of 308.15 K. With a waste heat source and cooling water temperature difference (TD) of 70 K in the 3-tank system, MOF–801/water outperforms aluminum fumarate and MIL-100(Fe). Considering a temperature driving force that explains the temperature change of heat transfer fluid during the flowing procedure inside pipes, ΔT = 5 K, the MOF–801/water pair can provide a gross temperature lift of around 30 K at a relatively good COP of 0.4867. There are very few articles that studied the MOFs/water pair for AdHT 2-tank and 3-tank system applications. Hence, the results of this study highlight their viability for designing environmentally friendly and energy-efficient heating systems.

The Effect of Location, Time, and Environmental Conditions on Fish Use of Southern Temperate Saltmarshes

Fish use of saltmarsh varies spatially, temporally, and with environmental conditions. The specific impact of these effects on fish assemblages in southern temperate Tasmania, Australia—the only mangrove-free Australian state—is as yet largely unknown. Seasonal variation in fish abundance, richness, diversity, and size was investigated in succulent saltmarshes in three estuaries (Marion Bay, Barilla Bay, and Ralphs Bay) in south-eastern Tasmania. All parameters varied between sampling locations. Greater numbers of fish were recorded at two sites (Marion Bay, mean density and standard error of 396.9 ± 71.3 individuals per 100 m2; Barilla Bay, mean density and standard error of 94.1 ± 30.1 individuals per 100 m2) than have been previously reported in Australian saltmarshes. Fish abundance was greatest in July–August (mean density and standard error of 200.2 ± 49.7 individuals per 100 m2) reflecting the breeding patterns of the numerically dominant Atherinosoma microstoma. Both abundance and species richness responded positively to water temperature in ordinal logistic regression models, and species richness and diversity increased with water depth in the models. It is likely that the strong differences between sampling locations are partly related to differences in water depth and water temperature between the estuaries. They may be also related to the habitat context of each estuary, especially the presence or absence of seagrass. The greater numbers of fish found in the present study relative to abundances reported in mainland Australia may relate to the absence of mangroves and the consequent differences in seascape habitat context, including greater water depths in marshes. Importantly, these results demonstrate that temperate southern hemisphere saltmarshes are year-round habitat for fish, thus emphasising their importance as a fish habitat.

The Effect of Uneven Metal Foam Distribution on Solar Compound Parabolic Trough Collector Receiver Thermal Performance

Solar energy is a key player among other renewable energies that reduce greenhouse gases and replace conventional fuel, i.e., to solve global warming and fossil fuel descending issues. However, the thermal solar systems’ performance should be enhanced to cope with intermittent solar radiation. Metal foam can be used as an enhancer in solar collectors’ receivers. However, metal foams are associated with pressure drop. To benefit from the metal foam as a thermal enhancer and overcome the pressure drop issue, the present study numerically and experimentally investigates a novel Compound Parabolic Solar Collector (CPC) receiver with innovative uneven metal foam inserts of varying thickness. Two pores per inch (PPI) Cu-foam inserts, PPI10 and PPI20, were tested. These inserts were strategically placed at three different positions along the receiver, with thicknesses of 3 cm, 2 cm, and 1 cm starting from the inlet side. In the experimental part, three tubular receivers were tested, empty, i.e., without metal foam, inserted with Cu-foam of PPI10, and inserted with Cu-foam of PPI20. The experiments were conducted from 09:00 AM to 04:00 PM. The investigation involved water volume flow rates from 0.2 to 0.6 l/min. The numerical part included solving the governing equations, i.e., mass, momentum, and energy conservation, simulating conditions similar to the experiments. The Brinckman model described the fluid flow through the metal foam. The thermal performance of the CPC system was evaluated using the Nusselt number (Nu), thermal efficiency, water bulk temperature, and water outlet-inlet temperature difference. Inserting Cu-foam of PPI20 resulted in the hourly maximum Nu and thermal efficiency compared to the empty and PPI10 cases. Experimentally, the hourly maximum Nu was 8.9, 8.4, and 7.9 for PPI20, PPI10, and empty receivers, respectively, at 0.6 l/min. The average thermal efficiency was 88.3, 85, and 81.9 for PPI20, PPI10, and empty receivers, respectively, at 0.6 l/min. As for the outlet-inlet water temperature difference, the highest values were at 0.2 l/min. Again, PPI20 recorded the best results, i.e., 23.3 K, 21.5 K, and 20.2 K for PPI20, PPI10, and empty cases, respectively.

The Role of Terroir on the Ripening Traits of V. vinifera cv 'Glera' in the Prosecco Area.

The grapevine (Vitis vinifera L.) is widely cultivated worldwide owing to the substantial commercial value of the grapes and other products derived from their processing, wines in particular. The grapevine is characterized by a remarkable phenotypic plasticity within the same variety, which shapes the final berry quality attributes hence reflecting the complex interactions between the plant and the environment leading to the expression of wine typicity. In this study, we explored the metabolomic and transcriptomic basis of the plasticity of Glera, a white berry grapevine variety particularly renowned for the production of wine Prosecco. The two selected vineyards varied for site altitude and pedoclimatic conditions. We highlighted that these environments determined different berry ripening dynamics at the level of both technological parameters and the total abundance and intrafamily distribution of phenolic compounds. Moreover, a clear impact on the grape aroma profile was observed. The genome-wide gene expression analysis of the berries revealed remarkable differences in the ripening transcriptomic program, reflecting the differences in water status, light exposure, and temperature experienced by the plants while growing at the two sites. Overall, this survey portrayed how the quality attributes of the cv 'Glera' grape berries may be affected by different environmental conditions within the typical area of Prosecco wine production.

Experimental investigation of a novel-designed inclined solar still with bio-wick under dynamic water flow

ABSTRACT This study experimentally investigates the inclined solar still (ISS) with the incorporation of fins and natural bio-jute cloth under dynamic flow. Experiments are conducted on bright sunny summer days in Coimbatore, Tamil Nadu, India. The newly developed ISS features greatly support passive solar desalination. An increase in mass flow rate (Mf) increases heat transfer meticulously pointing out 0.65, 0.8, and 1 kg/min case absorber, and the water temperature difference is within 3°C. An Mf of 0.285 kg/min is secure for the maximum water temperature reach and clean water yield of 70°C and 4.1 kg/m2, respectively, along with jute cloth, it was 1.6 kg/m2 more against without jute cloth. The presence of a jute cloth cumulative water yield of 2.5 kg/m2 at 0.635 kg/min is very close to the absence of a wick cumulative yield of 2.3 kg/m2 during 0.285 kg/min. From these results, the authors conclude higher Mf is feasible to increase the still performance and clean water yield. The implementation of a fully renewable passive solar still is strongly recommended to attain renewable and sustainable desalination.

A data compilation of antibiotic treatments in Canadian finfish aquaculture from 2016 to 2021 and the cumulative usage of antibiotics and antiparasitic drugs at marine sites

Antibiotics can be introduced from aquaculture facilities into marine sediments, where they may affect benthic communities and generate antimicrobial resistance (AMR). Antibiotics can be used in tandem with antiparasitics, and the effects of their combined usage could affect AMR patterns and transmit antibiotic resistance genes. This study compiles patterns of antibiotic and antiparasitic drug usage from 2016 to 2021 in British Columbia, New Brunswick, Newfoundland and Labrador, and Nova Scotia (Canada) and compares them internationally. There is an overall reduction in rates of antibiotic use per fish produced in Canadian aquaculture sites from 2016 to 2021. Compared to other salmon-producing countries, Canadian antibiotic rates per tonne of fish are lower than in Chile, but higher, on average, than in Norway and Scotland. Florfenicol (FLO) and oxytetracycline (OTC) are the prevalent antibiotics used in most salmon-producing countries, including Canada. We also note that &lt;30% of sites used two drugs per year and &lt;18% of sites used three drugs, with most of these sites using one antibiotic and one antiparasitic. There is an increase in FLO and a decrease use in OTC use in Canada, which could be positive environmentally considering FLO's lower dose and environmental persistence. The east and west coasts show comparable antibiotic rates, with an average rate of 78 mg/kg in BC and 76 mg/kg in the Atlantic provinces; however, they have differences in the type of antibiotic (average use of OTC: BC 38 mg/kg vs. Atlantic 214 mg/kg; average use of FLO: BC 40 mg/kg vs. Atlantic 10 mg/kg). Other distinctions between coasts include variation in the timing of treatments, with seasonal use in the Atlantic provinces (May–November) and year-round use in BC. This pattern is likely influenced by differences in water temperature and, subsequently, potential susceptibility to aquatic diseases. Disease prevalence and veterinarian choice/preferred treatments are factors that, we hypothesize, may impact treatment choice; however, additional information is required to adequately comment on this point. This data compilation includes spatial descriptions that could be used for area prioritization in future studies.

Sediment trap samples reveal regional differences in the population structure of Calanus hyperboreus from the Arctic Ocean

Abstract Calanus hyperboreus is one of the dominant copepod species in the Arctic zooplankton communities. The impact of climate change varies among regions within the Arctic, implying that C. hyperboreus populations may be differently affected at different locations, but knowledge on seasonal population dynamics in relation to biogeography is scarce. To fill this gap, we counted C. hyperboreus in samples from sediment traps that were moored from 2009 to 2014 in three regions of the Arctic Ocean (eastern Fram Strait, northern Chukchi Sea and MacKenzie Trough). The C. hyperboreus flux increased between April and May in all regions, likely associated with the ascent from overwintering depth to the surface. In the descent period, high fluxes were observed between July and September in the Fram Strait, between September and November in the northern Chukchi Sea, and between August and October in the MacKenzie Trough, suggesting that the timing of descent varied among the regions characterized by differences in light regime, phytoplankton development and water temperature. The copepodite stage composition in the eastern Fram Strait and the MacKenzie Trough varied with season, suggesting successful local reproduction while it was uniform in the northern Chukchi Sea, possibly because the population is fueled by advection.