Moderate Water Temperatures Research Articles

The modified artificial cohort method for three dominant pelagic copepods in the northern North Pacific revealed species-specific differences in the optimum temperature

The most concerning recent ocean changes in temperature issues are known as marine heat waves. Under these conditions, it is important to evaluate the effects of temperature on zooplankton. In this study, we investigated the growth rates of three dominant copepod species (Eucalanus bungii, Metridia pacifica, and Neocalanus plumchrus) in the northern North Pacific under three different temperature conditions (3, 7, and 11°C) using an artificial cohort method. Experimental conditions for 42 hour incubations were set to light intensity and photoperiod corresponding to 50 m depth. The dissolved oxygen solubility after rearing ranged from 69.2% to 102.1%, suggesting sufficient conditions for copepod growth. Chlorophyll a increased in 83% of the experiments, indicating that the food conditions were sufficient for the copepods. The mean proportion of dead specimens evaluated using neutral red was 10.2%, corresponding with the reported values in the field. Thus, it can be concluded that the laboratory-rearing conditions used in this study provided sufficient food, and the only effect evaluated would be that of the three different temperatures. Since the developmental time for each stage is longer than the rearing period, it is important to conduct experiments with a large number of individuals to obtain accurate growth rate results. The specific growth rates of E. bungii and M. pacifica increased with increasing temperature. In contrast, N. plumchrus showed the highest growth rate under moderate water temperature conditions. In terms of weight units (dry, carbon, and nitrogen), the carbon weight-specific growth rates were higher than those of the other two units, a common characteristic of the three species. This reflected lipid accumulation during the late copepodite stages. The interspecies differences in growth rate responses to water temperature reflect species-specific differences in temperature tolerance or the optimum temperature for each species. As E. bungii and M. pacifica reproduce near the surface layer through income breeding, their temperature tolerance or optimum temperature is expected to be high. However, because the reproduction of N. plumchrus occurs in the cold deep layer by using capital breeding, its temperature tolerance and optimum temperature would be lower than those of the former two species.

Lake surface and downstream river temperature response to the retreat of a lake‐terminating glacier

AbstractGlacier contributions to streamflow moderate summer water temperatures and help keep rivers cool during periods of hot, dry weather. As glaciers retreat, the length of channel exposed to solar radiation above a given point of interest would increase, which should ultimately result in higher water temperatures. However, formation of proglacial lakes may complicate river temperature response to glacier retreat. This study examined river and lake temperature response to the retreat of lake‐terminating Bridge Glacier, British Columbia, using a combination of manual spot and continuous river temperatures at a stream gauge, lake surface temperatures derived from Landsat imagery, and in situ lake temperatures made during a field campaign during summer 2013. Temperature data spanned the period from 1984 to 2022. Lake and river temperatures were relatively constant prior to and during a period of rapid retreat, but exhibited an upward trend following 2012, when iceberg density declined due to an apparent decrease in calving rate, resulting in an increase in lake surface area and river temperature of about 5°C even though the glacier remained lake terminating. In addition to providing the first longitudinal study of water temperature response to the retreat of a lake‐terminating glacier, this study adds to a body of literature that demonstrates that routine spot river temperatures, if collected in a consistent manner over a number of years, can provide valid information about river and stream temperature trends.

Long‐term survival of Atlantic salmon following catch and release: Considerations for anglers, scientists and resource managers

AbstractTo evaluate the scientific basis for catch and release as a management tool, a comprehensive 3‐year study compared long‐term survival of Atlantic salmon that were either angled, radio‐tagged and released, or trapped, radio‐tagged and released (control). Overall, the mean survival probability of angled salmon relative to the control group was between 0.94 and 0.98. At cool to moderate water temperatures (10–18°C) mean survival of angled salmon was between 0.96 and 0.98. Although the number of salmon caught and released above 21°C was low, catchability was slightly reduced at warm water temperatures (21–25°C) and the mean survival probability was between 0.43 and 0.69. Lastly, the number of fish that survived the spawning period did not differ between the angled group and the control group. However, the mean percentage of fish that overwintered and migrated downstream through a counting fence to sea was between 9% and 10% for those that were caught and released and between 13% and 19% for the control group. Results of this study suggest that mortality of caught and released Atlantic salmon can be delayed but remains low at cool to moderate water temperatures.

The Initial Oxidation of HfNiSn Half-Heusler Alloy by Oxygen and Water Vapor.

The MNiSn (M = Ti, Zr, Hf) n-type semiconductor half-Heusler alloys are leading candidates for the use as highly efficient waste heat recovery devices at elevated temperatures. For practical applications, it is crucial to consider also the environmental stability of the alloys at working conditions, and therefore it is required to characterize and understand their oxidation behavior. This work is focused on studying the surface composition and the initial oxidation of HfNiSn alloy by oxygen and water vapor at room temperature and at 1000 K by utilizing X-ray photoelectron spectroscopy. During heating in vacuum, Sn segregated to the surface, creating a sub-nanometer overlayer. Exposing the surface to both oxygen and water vapor resulted mainly in Hf oxidation to HfO2 and only minor oxidation of Sn, in accordance with the oxide formation enthalpy of the components. The alloy was more susceptible to oxidation by water vapor compared to oxygen. Long exposure of HfNiSn and ZrNiSn samples to moderate water vapor pressure and temperature, during system bakeout, resulted also in a formation of a thin SnO2 overlayer. Some comparison to the oxidation of TiNiSn and ZrNiSn, previously reported, is given.

Excitation-emission matrix fluorescence spectra of chromophoric dissolved organic matter reflected the composition and origination of dissolved organic carbon in Lijiang River, Southwest China

Aquatic photosynthesis transforms inorganic carbon to organic carbon (OC), which contributes to autochthonous organic carbon (AOC) in sediment and particulate organic carbon in surface karst aquatic systems. Aquatic plant and microbes are participated in autochthonous dissolved organic carbon (ADOC) formation in surface karst aquatic systems, but the composition and formation of ADOC remains little known, which leaves problem on calculation of organic carbon flux. In this study, the Lijiang River was chosen as typical surface karst river to identify the DOC composition and its origin, and to explore the environmental influencing factors. Samples were collected seasonally from the upper to lower reaches of the river to analyze hydrochemical parameters and the excitation-emission matrix (EEM) spectrum of chromophoricdissolved organic matter (CDOM). Three CDOM components were calculated by parallel factor analysis (PARAFAC) from EEM spectra, which were allochthonous soil-sourced DOC (SDOC), autochthonous aquatic plant-sourced DOC (APDOC), and microbial-sourced DOC (MDOC). Based on the DOC component concentrations, SDOC is induced by large amounts of precipitation causing soil erosion in summer. APDOC formation is encouraged by moderate water temperatures in spring and fall restricted by high water turbidity in summer. The significant positive linear correlations between APDOC and dissolved inorganic carbon (DIC) and MDOC indicate DIC fertilization effect in karst aquatic systems directly promotes APDOC formation and indirectly promotes MDOC. Our study develops a relatively simple way to calculate composition of karst aquatic DOC, which demonstrates the participation of aquatic plants and microbes in APDOC production and reiterate that autochthonous DOC should be considered when calculating the carbon sink in surface karst aquatic systems.

Effect of water level and water quality on small‐sized and juvenile fish assemblages in the littoral zones of the Zambezi/Chobe floodplain

AbstractThe effect of flooding phase and water quality on the littoral fish species of the Zambezi/Chobe floodplain was assessed between March 2017 and February 2018. Using the similarity percentage analyses (SIMPER), a 61.9% dissimilarity was detected in fish assemblages among the four flooding phases of the Zambezi/Chobe floodplain (rising, peak, recession and low flooding phase). Cichlids (63.1%) were the most dominant taxa during the peak flooding phase while cyprinids were dominant during the rising (40.7%), recession (45.3%) and low flooding phases (40.9%), respectively. Juveniles of the two commercially important species, Oreochromis andersonii and Coptodon rendalli, were among the four abundant species across the four flooding phases of the Zambezi/Chobe floodplain. Higher densities of these two species were in synchrony with the peak flooding phase, characterised by high levels of dissolved oxygen (5.7 ± 1.0 mg/L), neutral pH (7.9) and moderate water temperature (27.6 ± 1.1°C). During the flood recession phase, a severe decline in juvenile of the commercially important species (O. andersonii and C. rendalli) coincided with fish migration off the littoral zone into the main river at a mean size between 70 and 80 mm SL. Generally, the observed variations in the fish species composition during the different stages of flooding might reflect the influence of water quality and water volume to sustain large fish assemblages on the littoral zone of the Zambezi/Chobe floodplain. Any change in the natural flow and reduction in water volume of the Zambezi/Chobe floodplain might negatively affect the recruitment of juvenile fish into adult populations.

Toxic effects and mechanisms of Prymnesium parvum (Haptophyta) isolated from the Pearl River Estuary, China

Prymnesium (Haptophyta) species form toxic blooms throughout the world resulting in large fish-kills and economic losses. A culture of Prymnesium parvum JX12 was isolated and established from the Pearl River Estuary of China. The toxic characteristics of JX12 to aquatic animals were investigated, considering the effects of temperature, salinity, and nutrients. Cultures of JX12 exhibited significant lethal toxicity to the fish, Mugil sp., M. soiuy, M. cephalus, Ctenogobius sp. and Chrysiptera parasema, and the brine shrimp, Artemia salina, but no significant effects on the shellfish Ruditapes variegatus and the shrimp Penacus orientalis. The toxicity of JX12 to A. salina increased with growth of the culture. The decline phase displayed the strongest potency, followed by the stationary phase, exponential phase and lag phase. Also, there was a significant difference in toxicity among culture fractions of JX12 compared to whole-cell culture. For example, the toxicity of a cell-free culture filtrate on brine shrimp was reduced by 50% by the end of the experiment, while the sonicated and re-suspended cultures caused near 100% mortality. The toxicity of JX12 was also regulated by environmental factors such as temperature, salinity and nutrients. The strongest toxicities were at moderate water temperature (20–25 °C) and salinity (35 psu). The toxicity was reduced significantly at higher or lower temperatures and salinities. Furthermore, the toxicity of JX12 was greatly enhanced when ambient nutrients were deficient. Due to the potent toxicity of JX12 to multiple aquatic animals, especially fish and zooplankton, this species threatens the food web and trophic dynamics of coastal ecosystems. This study suggested that the ability to produce and release toxin(s) is an effective competition strategy for P. parvum to suppress predators and sympatric competitors and thus form blooms.

Aquatic macroinvertebrate richness and diversity associated with native submerged aquatic vegetation plantings increases in longer-managed and wetland-channeled effluent constructed urban wetlands

Macroinvertebrate community structure and assemblages associated with the planted, native submerged aquatic vegetation (SAV) species Heteranthera dubia (Jacq.) MacMillan and Potamogeton nodosus Poiret were examined in a series of constructed urban floodway wetlands, the Dallas Floodway Extension Lower Chain of Wetlands, Dallas, TX, USA. Macroinvertebrate community metrics, including abundance, richness, diversity, and evenness associated with SAV and three different wetlands of varying construction completion dates, water sources (direct or wetland-channeled wastewater effluent), and ecosystem management stage (established/reference or developing) were compared and analyzed. Assemblages at sampling sites were also classified and related to vegetation and wetland physicochemical parameters. Plant species affected only macroinvertebrate abundance, with the less-dissected P. nodosus supporting higher counts than H. dubia. Wetland age and water-effluent type had the most substantial effect on macroinvertebrate communities. The older, longer-managed wetland and wetland-channeled effluent habitat consistently demonstrated higher quality metrics and biodiversity than newly constructed, direct effluent wetland habitat. Increased vegetation cover and wetland age, coupled with moderate water temperature, pH, and DO levels were characteristics of more rich and diverse macroinvertebrate communities, including pollutant-sensitive taxa, such as Ephemeroptera and Trichoptera.

Coral reef ecosystem functioning: eight core processes and the role of biodiversity

Coral reefs are in global decline. Reversing this trend is a primary management objective but doing so depends on understanding what keeps reefs in desirable states (ie “functional”). Although there is evidence that coral reefs thrive under certain conditions (eg moderate water temperatures, limited fishing pressure), the dynamic processes that promote ecosystem functioning and its internal drivers (ie community structure) are poorly defined and explored. Specifically, despite decades of research suggesting a positive relationship between biodiversity and ecosystem functioning across biomes, few studies have explored this relationship in coral reef systems. We propose a practical definition of coral reef functioning, centered on eight complementary ecological processes: calcium carbonate production and bioerosion, primary production and herbivory, secondary production and predation, and nutrient uptake and release. Connecting research on species niches, functional diversity of communities, and rates of the eight key processes can provide a novel, quantitative understanding of reef functioning and its dependence on coral reef communities that will chart the transition of coral reefs in the Anthropocene. This will contribute urgently needed guidance for the management of these important ecosystems.

Movement and Home Range of the Smooth Softshell Turtle (Apalone mutica): Spatial Ecology of a River Specialist

Spatial ecological information is necessary to guide the conservation efforts of river turtles, but it is lacking for many species including the smooth softshell turtle (Apalone mutica). We investigated the spatial ecology of A. mutica in two reaches of the Kaskaskia River in Illinois, USA to determine variables influencing movement rates, the best estimate of home range, and variables influencing home range size. We radio-tracked 28 A. mutica from 2013 to 2014 and used an information theoretic approach to select the best models describing movement and home range estimates. Mean movement rate was 142.3 m/day and was highly variable with some movements >2 km/day. Movement peaked at moderate water temperatures early in the active season, increased at higher water levels for females, and was greater in the higher stream order. The sexes responded differently to environmental variation, with female movement higher in most but not all conditions. The most informative home range estimate was a 95% kernel density estimate using likelihood cross-validation (CVh) smoothing clipped to the river channel. The mean home range size was 18.1 hectares and increased with movement rate, number of radio-locations, and stream order. Most turtles had well-defined home ranges, though a few were possibly nomadic. Our methods also provide a framework for spatial ecological studies of other riverine species.

Role of riparian wetlands and hydrological connectivity in the dynamics of stream thermal regimes

AbstractStream temperature is a fundamental physical characteristic of rivers, influencing biological productivity and water quality. Given the implications of climate warming for stream thermal regimes, it is an important consideration in river management plans. Energy exchanges at the water–air interface, channel geomorphology, riparian vegetation and advective heat transport from the different sources of discharge can all influence stream temperature. A simple mixing equation was used to investigate heat transport and to estimate daily mean and maximum stream temperatures on the basis of mixing groundwater and near-surface flows from riparian wetlands as end-members in a peatland catchment. The resulting data were evaluated against energy balance components and saturation extent to investigate the importance of riparian wetlands in determining stream temperatures. Data fit was generally good in periods with extensive saturation and poorest in dry periods with less hydrological connectivity, when reduced saturation and low flows increased the relative influence of energy exchange at the stream–atmosphere interface. These findings have implications in terms of climate change and land management, where the planting of riparian buffer strips to moderate water temperatures may be less effective when saturation area is extensive and hydrological connectivity is high.

Effects of moss-dominated biological soil crusts on soil enzyme activities in water-wind erosion crisscross region on the Loess Plateau of China

The 30-year-old biological soil crusts dominated by mosses (hereafter moss crusts) and corresponding uncrusted soil (hereafter no crust) were sampled on loess soil and aeolian soil at 0-12 cm depth on the Loess Plateau of China. Afterwards, the hydrolase activities of the samples were measured, and their correlations with soil physicochemical properties were analyzed. Compared with no crust, the activities of urease, alkaline phosphatase, invertase, and protease of the moss crusts were 2.4, 7.6, 20.7, 2.4 times higher on loess soil, respectively; while they were 3.5, 22.2, 22.3, 2.0 times higher on aeolian soil, respectively. Compared with no crust, the soil water content of the moss crusts was decreased by 6.5% and 0.8% on loess soil and aeolian soil, and the soil temperature of the moss crusts was decreased by 0.8 and 2.5 ℃, respectively; the contents of soil organic matter, alkali-hydrolyzable nitrogen, and available phosphorus of the moss crusts were 2.5, 2.9 and 3.6 times higher on the loess soil, and they were 3.6, 3.0 and 6.6 times higher on the aeolian soil, respectively. The soil hydrolase activities were positively correlated with the soil nutrient content and negatively correlated with the soil water content. Soil temperature was positively correlated with the urease activity and negatively correlated with the protease activity. The moss crusts significantly improved soil nutrients and fertility through increasing soil enzyme activities on the Loess Plateau of China, and these effects were reasonably attributed to the moderate soil water content and temperature regulated by the moss crusts.

From Space to the Rocky Intertidal: Using NASA MODIS Sea Surface Temperature and NOAA Water Temperature to Predict Intertidal Logger Temperature

The development of satellite-derived datasets has greatly facilitated large-scale ecological studies, as in situ observations are spatially sparse and expensive undertakings. We tested the efficacy of using satellite sea surface temperature (SST) collected by NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) and local water temperature collected from NOAA buoys and onshore stations to estimate submerged intertidal mussel logger temperatures. Daily SST and local water temperatures were compared to mussel logger temperatures at five study sites located along the Oregon coastline. We found that satellite-derived SSTs and local water temperatures were similarly correlated to the submerged mussel logger temperatures. This finding suggests that satellite-derived SSTs may be used in conjunction with local water temperatures to understand the temporal and spatial variation of mussel logger temperatures. While there are limitations to using satellite-derived temperature for ecological studies, including issues with temporal and spatial resolution, our results are promising.

Water temperature and oxygen: The effect of triploidy on performance and metabolism in farmed Atlantic salmon (Salmo salar L.) post-smolts

The use of sterile triploids in Atlantic salmon aquaculture would mitigate the environmental risks associated with introgressive hybridization between escaped farmed and wild Atlantic salmon. However, production of farmed triploid salmon is limited due to reports of poorer growth and higher mortality when compared to diploids, in particular under sub-optimal environmental conditions. To address these concerns, we monitored triploid and diploid Atlantic salmon post-smolts at temperatures between 3 and 18°C and 100% oxygen saturation (O2 sat), and additional periods of 60% O2 sat (hypoxia) at 6 or 18°C, respectively. Feed intake and oxygen consumption rate were monitored throughout the experimental period. Muscle and blood samples were collected at 100 and 60% O2 sat at 6 and 18°C for analysis of white muscle energy phosphates (creatine phosphate, adenosine triphosphate) and carbohydrate fuels (glucose, glycogen) as well as blood clinical chemistry (whole blood: hematocrit; plasma: Na+, K+, Cl−, glucose, lactate, pH, triacylglycerol). Mortality was similar between ploidies, but higher in triploids compared to diploids during reduced O2 sat at 18°C. Compared to diploids, triploids had higher feed intake (% biomass) at ≤9°C, but lower feed intake at ≥15°C. Feed intake peaked at 12 and 15°C for triploids and diploids, respectively. Triploids progressively reduced feed intake with increasing temperature after peak feeding, indicating reduced scope for specific dynamic action with increasing water temperature. During hypoxia, triploids had lower feed intake than diploids at 6 and 18°C. The difference in feed intake was not associated with any ploidy effect on body weight gain or feed conversion ratio, but triploids had greater body length growth compared to diploids. At ≥15°C triploids consumed less oxygen than diploids. In the white musculature, the only observed difference between ploidies was a lower level of glycogen in triploids compared to diploids at 18°C and 100% O2 sat. In the blood plasma, the concentration of ions was lower and glucose level higher in triploids compared to diploids at 18°C and 60% O2 sat. The results of this study indicate that triploid Atlantic salmon post-smolts can substitute diploids, but are less tolerant to high seawater temperature and low O2 sat. For sea-cage farming of triploid salmon post-smolts, this would favour production areas with maximum temperatures of 15°C and sufficient oxygen. Statement of RelevanceThis study demonstrates that triploid Atlantic salmon post-smolts have lower temperature optima for feeding and growth than diploids, a similar physiological response to high temperatures, but higher mortality under suboptimal conditions. Consequently triploid Atlantic salmon post-smolts may be well suited for commercial farming in geographical regions with moderate water temperatures in the summer and autumn months.

The physiological adaptations and toxin profiles of the toxic Alexandrium fundyense on the eastern Bering Sea and Chukchi Sea shelves

Abundant cyst distributions of the toxic dinoflagellate Alexandrium fundyense (previous A. tamarense north American clade) were recently observed on the north Chukchi Sea shelf and on the eastern Bering Sea shelf, suggesting that A. fundyense is both highly adapted to the local environments in the high latitude areas and might cause toxin contamination of plankton feeders. However, little is known about the physiological characteristics and toxin profiles of A. fundyense in these areas, which are characterized by low water temperatures, weak sunlight, and more or less permanent ice cover during winter. To clarify the physiological characteristics of A. fundyense, the effects of water temperature and light intensity on the vegetative growth and toxin profiles of this species were examined using A. fundyense strains isolated from one sediment sample collected from each area. Using the same sediments samples, seasonal changes of the cyst germination in different water temperatures were investigated. Vegetative cells grew at temperatures as low as 5°C and survived at 1°C under relatively low light intensity. They also grew at moderate water temperatures (10–15°C). Their cysts could germinate at low temperatures (1°C) and have an endogenous dormancy period from late summer to early spring, and warmer water temperatures (5–15°C) increased germination success. These physiological characteristics suggest that A. fundyense in the Chukchi Sea and eastern Bering Sea is adapted to the environments of high latitude areas. In addition, the results suggest that in the study areas A. fundyense has the potential to germinate and grow when water temperatures increase. Cellular toxin amounts of A. fundyense strains from the eastern Bering Sea and Chukchi Sea were ranged from 7.2 to 38.2 fmol cell−1. These toxin amounts are comparable with A. fundyense strains isolated from other areas where PSP toxin contamination of bivalves occurs. The dominant toxin of the strains isolated from the Chukchi Sea was saxitoxin, while most A. fundyense strains from the eastern Bering Sea are dominated by the C2 toxin. Toxin profiles similar to those detected in Chukchi Sea have not been reported by any previous research. The dominance of a highly toxic PST variant in Chukchi A. fundyense suggests that presence of the species at low cell concentrations may cause toxin contamination of predators. This study revealed that abundant A. fundyense cysts deposited on the eastern Bering Sea and Chukchi Sea shelves potentially germinate and grow with PSP toxin contents in the local environments. In conclusion, a high risk of PSP occurrences exists on the eastern Bering Sea and Chukchi Sea shelves.

Spatiotemporal drivers of energy expenditure in a coastal marine fish.

Animal behavior and energy expenditure often vary significantly across the landscape, and quantifying energy expenditure over space and time provides mechanistic insight into ecological dynamics. Yet, spatiotemporal variability in energy expenditure has rarely been explored in fully aquatic species such as fish. Our objective was to quantify spatially explicit energy expenditure for a tropical marine teleost fish, bonefish (Albula vulpes), to examine how bonefish energetics vary across landscape features and temporal factors. Using a swim tunnel respirometer, we calibrated acoustic accelerometer transmitters implanted in bonefish to estimate their metabolic rates and energy expenditure, and applied this technology in situ using a fine-scale telemetry system on a heterogeneous reef flat in Puerto Rico. Bonefish energy expenditure varied most among habitats, with significant interactions between habitat and temporal factors (i.e., diel period, tide state, season). The energy expenditure was generally highest in shallow water habitats (i.e., seagrass and reef crest). Variation in activity levels was the main driver of these differences in energy expenditure, which in shallow, nearshore habitats is likely related to foraging. Bonefish moderate energy expenditure across seasonal fluctuations in temperature, by selectively using shallow nearshore habitats at moderate water temperatures that correspond with their scope for activity. Quantifying how animals expend energy in association with environmental and ecological factors can provide important insight into behavioral ecology, with implications for bioenergetics models.

The Eemian/Early Vistulian development of the Solniki paleolake (north-eastern Poland) as shown by subfossil Cladocera

<p>This work presents results of a paleolimnological study focussed on subfossil Cladocera analysis and on different aspects of the evolution of the Solniki paleolake during the Eemian/Early Vistulian period. The study aimed at the reconstruction of the long-term dynamics of this paleoecosystem and at defining the conditions (<em>e.g</em>., water level, trophic status and water temperature) of the ancient lake. Paleolacustrine deposits of ca. 10 m thickness were discovered at Solniki during cartographic works for the Trześcianka sheet of the Detailed Geological Map of Poland. This archives recorded one full-interglacial sequence (Eemian Interglacial), one interstadial warming (Brørup) and two stadial coolings (Herning and Rederstall) stages, which were confirmed by palynological analyses. The subfossil Cladocera fauna from the Solniki paleolake consisted in 17 species belonging to the families Bosminidae, Chydoridae, Sididae and Daphniidae. Littoral species were dominant (52%), the most frequent of which were <em>Alona affinis</em> and <em>Camptocercus rectirostris</em>. The most abundance pelagic species were <em>Eubosmina coregoni</em> and <em>Bosmina longirostris</em>. The sediment species composition was quite similar to that of contemporary Central European lakes. The early and the late stages of Eemian Interglacial were likely the most favourable periods for the Cladocera development in the paleolake, in relation to higher water level, moderate water temperature and the mesotrophic state of water. A further ecologically favourable period was the Brørup Interstadial. The highest species richness, abundance, and diversity during the whole paleolake existence were recorded during these three periods. Surprisingly, the middle of the Middle Eemian Interglacial climate optimum appeared as an unfavourable period for the Cladocera growth as it was associated with decreasing water level and pronounced climate fluctuations. This sequence was also recorded by other studies of Eemian lakes in Central Europe.</p>

Tea, coffee intakes and risk of oral squamous cell carcinoma: a case-control study

Objective: To evaluate the effects of tea and coffee intakes on oral squamous cell carcinoma (OSCC) stratified by milk intake. Methods: A case-control study involving 593 OSCC patients confirmed by pathological diagnoses and 1 128 gender-age frequency matched controls was conducted in Fujian province during September 2010-March 2016. Unconditional logistic regression was used to calculate adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CIs) to assess the effects of coffee, tea intakes and related variables on OSCC. Additive interaction was estimated by relative excess risk interaction (RERI), attributable proportions interaction (API) and synergy index (SI). Results: Tea intake was significantly associated with decreased risk of OSCC: the adjusted ORs were 0.54 for all subjects (95%CI: 0.41-0.71), 0.47 for milk consumers (95%CI: 0.31-0.71) and 0.57 for non-milk consumers (95%CI: 0.40-0.81). Moreover, starting tea drinking at age ≥25 years, moderate tea concentration and water temperature, drinking green tea and oolong tea showed effects to decrease the risk for OSCC in three groups. Additionally, there was a tendency of a reduced risk with increased daily tea drinking and longer tea-drinking period (all trend P<0.05). No significant association was observed between coffee intake and OSCC. A multiplicative but not additive interactions was found between tea drinking and milk intake. Additionally, we did not observe multiplicative and additive interaction between coffee drinking and milk intake. Conclusion: Tea drinking is a protective factor for OSCC, and there is a multiplicative interaction between tea drinking and milk intake. Therefore, tea drinking and increasing intake of milk can reduce the risk of OSCC at certain extent.

Evaluation of catch-and-release angling practices for the fat snook Centropomus parallelus in a Brazilian estuary

Recreational fisheries are developing for many iconic marine and estuarine fish species and are generating important social and economic returns in Brazil. Fat snook is the primary target species in southeastern Brazil and it supports a vibrant fisheries sector, including recreational fishing tournaments. To evaluate the impacts of recreational angling practices, we examined external hooking injuries, secondary physiological stress responses (i.e., blood glucose and lactate concentrations; N = 24), reflex impairment (N = 39), and overnight survival (N = 39) of fat snook angled with and without air exposure. We also examined physiological stress and reflex impairment of fat snook captured in a fishing tournament (N = 43) immediately post weigh-in and 1 h post weigh-in. Values were compared to baseline reflexes (N = 10) and physiology (N = 8) collected from minimally stressed fat snook. Fish captured by anglers infrequently had hooking injury but all angling and tournament treatments resulted in significantly elevated blood glucose and lactate, indicating a considerable physiological response to angling. Angling with air exposure and tournament weigh-in (in a dry container) resulted in the highest blood lactate values. The body flex reflex was occasionally impaired after angling or tournament practices, but this was consistent with baseline reflex actions, and the body flex reflex was therefore not a valuable indicator of fisheries stress or mortality in fat snook. Although angling and tournament practices caused a marked physiological stress response, low mortality of snook indicated that the species is resilient to brief bouts of angling at moderate water temperatures. However, high lactate values associated with air exposure suggest that handling practices be refined, particularly during tournament weigh-in. We recommend that anglers reduce air exposure intervals when handling snook prior to release and that recreational tournaments adopt wet weigh-in procedures to maximize the utility of catch-and-release in this fishery.

Probability-based classifications for spatially characterizing the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region, Taiwan.

Accurately classifying the spatial features of the water temperatures and discharge rates of hot springs is crucial for environmental resources use and management. This study spatially characterized classifications of the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region of Northern Taiwan by using indicator kriging (IK). The water temperatures and discharge rates of the springs were first assigned to high, moderate, and low categories according to the two thresholds of the proposed spring classification criteria. IK was then used to model the occurrence probabilities of the water temperatures and discharge rates of the springs and probabilistically determine their categories. Finally, nine combinations were acquired from the probability-based classifications for the spatial features of the water temperatures and discharge rates of the springs. Moreover, various combinations of spring water features were examined according to seven subzones of spring use in the study region. The research results reveal that probability-based classifications using IK provide practicable insights related to propagating the uncertainty of classifications according to the spatial features of the water temperatures and discharge rates of the springs. The springs in the Beitou (BT), Xingyi Road (XYR), Zhongshanlou (ZSL), and Lengshuikeng (LSK) subzones are suitable for supplying tourism hotels with a sufficient quantity of spring water because they have high or moderate discharge rates. Furthermore, natural hot springs in riverbeds and valleys should be developed in the Dingbeitou (DBT), ZSL, Xiayoukeng (XYK), and Macao (MC) subzones because of low discharge rates and low or moderate water temperatures.