Comparative analysis of four stem taper models for Quercus glauca in Mount Halla,Jeju Island,South Korea

This study was conducted to fit the diameter-height data of Quercusglaucain Jeju Island, South Korea to the four commonly used stem taper equations andto evaluate the performance of the four stem taper models using four statistical criteria： Fit index （FI）, root mean square error （RMSE）, bias （）,and absolute mean difference （AMD）. Results showed that the Kozak02stem taper equation provided the best FI（0.9847）, RMSE（1.5745）,（-0.0030 cm） and AMD （1.0990 cm） whileMax and Burkhart model had the poorest performance among the four stem taper models based on the four evaluation statistics （FI ： 0.9793,RMSE ： 1.8272, ： 0.3040 cm and AMD ： 1.3060 cm）. These stem taper equations can serve as a useful tool for forest managers in estimating the diameter outside bark at any given height, merchantable stem volumes and total stem volumesof the standing trees of Quercusglaucain theGotjawal forests located in Mount Halla, Jeju Island, South Korea.     

The reproductive cycle of the humbug damselfish <Emphasis Type="Italic">Dascyllus aruanus</Emphasis> according to the changes in lunar phase in Micronesia

The moon is known to be an environmental factor that controls the reproductive cycle of fish, and fish have evolved a variety of reproduction patterns depending on the lunar phase. In this study, we examined the relationship between lunar phases and the reproductive cycle of the humbug damselfish Dascyllus aruanus inhabiting Weno Island, Chuuk Lagoon, Micronesia. We divided the one-month lunar cycle into eight phases, and measured the features of moonlight (peak wavelength and intensity) and indicators of fish maturity [gonadosomatic index (GSI) and sex hormones] in relation to the eight lunar phases. In addition, we investigated the daily rhythms of sex hormones in fish ovaries during the full moon phase. The results showed that the peak wavelength of moonlight was 430 nm (blue wavelength region) regardless of the lunar phase, and that moonlight intensity was highest during a full moon at 02:00. Furthermore, the GSI and sex hormones were both higher around the full moon phase. These findings support the hypothesis that humbug damselfish spawn once a month and that this event occurs at full moon, which is the phase of the moon with the strongest intensity. Based on these findings, we predict that blue wavelength, the dominant wavelength of moonlight, is one of the environmental factors influencing the monthly spawning of D. aruanus.     

Effect of different wavelengths of light on the antioxidant and immunity status of juvenile rock bream, <Emphasis Type="Italic">Oplegnathus fasciatus</Emphasis>, exposed to thermal stress

We investigated the effect of light wavelengths on antioxidant and immunity parameters in juvenile rock bream, Oplegnathus fasciatus, exposed to thermal stress (25 and 30°C). We exposed the fish to light emitting diodes (LEDs) emitting green (520 nm) and red light (630 nm) of 0.25 and 0.5 W/m² intensity, and measured the activity, and mRNA and protein expression levels of the antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase. We also determined the levels of plasma hydrogen peroxide (H₂O₂), melatonin, and lysozyme. Furthermore, the mRNA and protein levels of caspase-3 were measured and terminal transferase dUTP nick end labeling (TUNEL) assays were performed. We observed that mRNA expression and activities of antioxidant enzymes and plasma H₂O₂ levels were significantly higher after exposure to high temperatures. However, increases in these parameters were significantly lower after exposure to green LED light. The plasma melatonin and lysozyme levels were significantly lower in the different groups after exposure to high temperatures; however, in groups exposed to green LED light, their levels were significantly higher than those in the control group. The expression pattern of caspase-3 mRNA was similar to that of H₂O₂. The TUNEL assay showed that apoptosis was markedly higher at higher water temperatures than that at 20°C. These results indicate that high water temperatures induce oxidative stress and decrease the immunity in juvenile rock bream but green LED light inhibits the rise in oxidative stress and combats the decrease in immunity and should, thus, be useful in the culture of rock bream.     

Simulations of energy balance components at snow-dominated montane watershed by land surface models

The quantification of energy interactions among land surface, atmosphere, and surface vegetation is significant to comprehend the hydrological cycle in montane watersheds. Moreover, elevation change is an essential in causing variations in energy fluxes. Thus, estimating the major components of energy interactions is essential for better understanding of the hydrological process. The advanced land surface models (LSMs); the common land model (CLM) and variables infiltration capacity (VIC) are used to estimate accurate hydrometeorological variables. These hydrometeorological variables such as net radiation and sensible, latent, and ground heat fluxes were estimated using CLM and VIC at upper and lower meteorological stations in Sierra Nevada Mountain, California, USA. The estimated fluxes were compared with observations at each site. The estimated daily and monthly net radiation and sensible heat flux from both models showed good agreement with the observations (R ≥ 0.84). The CLM-modeled estimates showed lower trends during the rainfall periods, which occurred mainly during winter at both sites. In comparison, the estimated daily and monthly latent heat flux from CLM at both sites showed better results with lower RMSE and bias than that from VIC, which underestimated latent heat flux. Both models overestimated ground heat flux, and the variation trend was similar to observation. For sensitivity analysis, according to elevation change, all the estimated energy fluxes had slightly different values at the upper and lower met stations. In future studies, parameterization for the LSMs will be conducted for more robust estimations of hydrometeorological variables in montane watersheds.     

Effect of the North Atlantic Oscillation on the Thermal Characteristics of Lakes in Poland

This paper presents the effect of the North Atlantic Oscillation (NAO) on the thermal characteristics of lakes in Poland. In the analysis, the use was made of monthly air temperatures recorded at fifteen meteorological stations, water temperatures of twelve lakes, and Hurrell’s winter NAO indices. Over the study period (1971–2010), there was a marked increase in the temperatures of both, air and lake waters. Depending on the NAO phase, water temperatures were observed to depart from mean values, being markedly higher than average (even by 1°C) in the positive winter NAO phase. The differences in water temperatures were statistically significant in the winter-spring season. In turn, in the negative NAODJFM phase lake water temperatures in winter and spring were markedly lower than average (in March even by 1.0°C). The unique response of some lakes depends on their morphometric parameters, including their mean depth.     

Flow Characteristics of Microbubble Suspensions in Porous Media as an Oxygen Carrier

Microbubble suspensions were generated as an oxygen carrier for aerobic biodegradation, and their flow characteristics in porous media were investigated. Commercial surfactants including sodium dodecyl sulfate (SDS), and dodecylethyldimethylammonium bromide (DEDAB), saponin (a natural surfactant), and collagen (a protein hydrolysate) were examined as base materials for generating microbubble suspensions. Among them, 2×CMC (critical micellar concentration) of SDS, DEDAB, and saponin developed microbubble suspensions with the highest gas hold‐up and half‐drainage time. Visualization of the flow patterns in sand showed that the microbubble suspensions were separated into a liquid and gas phase directly after injection, showing much faster movement of liquid phase flow. The gas front of the microbubble suspensions flowed in a plug‐flow manner, particularly in cases of SDS and DEDAB. The experimental results from both homogeneous and heterogeneous cells confirmed that the microbubble flow could overcome the heterogeneity in porous media. However, the plug‐flow characteristics and flow propagation of the microbubble suspensions to the low‐permeability zone was accompanied by a large pressure drop, which needs to be considered for future field application.