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Effective water demand management is critical for adaptation during drought periods. However, drought planning is challenged by the lack of rigorous water demand‐integrated measures and the limited number of drought event samples based on instrumental data. We propose a Normalized Reservoir Drought Index (NRDI) and associated drought event metrics that can inform reservoir operations. Using NRDI, we analyzed the effectiveness of demand management and paleo streamflow data in assessing drought risks—the exposure related to meeting water demands during certain drought events. We explored reservoir drought risk analysis using data from seven reservoirs in the western United States. The NRDI was derived from inflow and estimated water demand and subsequently compared to observed reservoir storage. The NRDI and event metrics demonstrated responsiveness to observed storage. Comparative analysis of drought risk using paleo and instrumental inflow highlighted the importance of paleo inflow, providing larger drought event samples and broader extreme ranges. Sensitivity of drought risks was quantified under varying demand conditions. As expected, the sensitivity was more significant in extreme events than moderate events. This paper provides an effective and robust measure for reservoir managers to manage water releases during drought periods and a valuable tool to assess reservoir risk to drought by considering natural variability more broadly, and providing a deeper understanding on the sensitivity of drought risk to demand alterations.

Uncertainty exists regarding the interaction between the El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) where ENSO is normally expected to be the leading mode. Moreover, the effect of global warming on the relationship between these two modes remains unexplored. Therefore, we investigated the ENSO-IOD linkage for the years 1950-2014 using reanalysis data and high-resolution climate model simulations. The 1950-2014 period is of particular interest as rapid Indian Ocean warming since the 1950s has had a huge impact worldwide. Our results showed that the IOD had robust causal effects on ENSO, whereas the impact of ENSO on IOD exhibited lower confidence. All models demonstrated that the IOD was unlikely to have no causal effects on ENSO, whereas eight out of 15 studied models and the reanalysis data showed significant causal effects at the 10% significance level. The analyses provide new evidence that ENSO interannual variability might be forced by changes in Indo-Pacific Walker circulation induced by the IOD. Weak control of ENSO on the IOD is likely due to nonsignificant effects of ENSO on the western tropical Indian Ocean, implying that the rapid warming environment in the Indian Ocean may fundamentally modulate the relationship between the IOD and ENSO. We find high agreement between the models and reanalysis data in simulating the ENSO-IOD connection. These results indicate that the effects of the IOD on ENSO might be more significant than previously thought.

Heat stress has detrimental effects on livestock via diverse immune and physiological changes; heat-stressed animals are rendered susceptible to diverse diseases. However, there is relatively little information available regarding the altered immune responses of domestic animals in heat stress environments, particularly in cattle steers. This study aimed to determine the changes in the immune responses of Holstein and Jersey steers under heat stress. We assessed blood immune cells and their functions in the steers of two breeds under normal and heat stress conditions and found that immune cell proportions and functions were altered in response to different environmental conditions. Heat stress notably reduced the proportions of CD21⁺MHCII⁺ B cell populations in both breeds. We also observed breed-specific differences. Under heat stress, in Holstein steers, the expression of myeloperoxidase was reduced in the polymorphonuclear cells, whereas heat stress reduced the WC1⁺ γδ T cell populations in Jersey steers. Breed-specific changes were also detected based on gene expression. In response to heat stress, the expression of IL-10 and IL-17A increased in Holstein steers alone, whereas that of IL-6 increased in Jersey steers. Moreover, the mRNA expression pattern of heat shock protein genes such as Hsp70 and Hsp90 was significantly increased in only Holstein steers. Collectively, these results indicate that altered blood immunological profiles may provide a potential explanation for the enhanced susceptibility of heat-stressed steers to disease. The findings of this study provide important information that will contribute to developing new strategies to alleviate the detrimental effects of heat stress on steers.

Residual feed intake (RFI) is a widely used indicator of feed efficiency in cattle; however, its relationship with the fecal microbiota of Hanwoo, a Korean native cattle breed, has not yet been explored. This study aimed to examine the fecal microbiota composition of Hanwoo steers exhibiting divergent RFI at the fattening stage. Sixty-three Hanwoo steers were raised under the same dietary and environmental conditions and fed a total mixed ration. A 78-day feeding trial was conducted (from 19 to 21 months of age), during which growth performance was evaluated. Steers were ranked by RFI, and those with RFI values < − 0.6 or > 0.6 were selected to represent two extreme RFI phenotypes: low RFI (L-RFI; efficient; −0.96 ± 0.14, n  = 6) and high RFI (H-RFI; inefficient; 0.96 ± 0.48, n  = 5). Fecal samples were collected from both L-RFI and H-RFI steers at the end of the feeding trial for metataxonomic analysis using 16S rRNA amplicon sequencing and the QIIME2 pipeline. Average daily gain (ADG) and body weight were similar between the two groups, but dry matter intake (DMI) and RFI values were significantly higher in H-RFI steers. Bacterial alpha- or beta-diversity did not differ significantly between the two RFI groups. Linear Discriminant Analysis (LDA) coupled with Effect Size measurements (LEfSe) revealed that the phylum Verrucomicrobiota and its representative genus Akkermansia were the most abundant in the L-RFI group (LDA score > 2, P  < 0.05). In contrast, the genera Acetitomaculum and Kandleria were the most abundant in the H-RFI group (LDA score > 2, P  < 0.05). Functional analysis based on PICRUSt2 predictions revealed that H-RFI steers had higher abundances of genes associated with carbohydrate utilization and amino acid biosynthesis compared to L-RFI steers (LDA score > 2, P  < 0.05). The findings of this study demonstrate that feed efficiency is associated with the fecal microbial composition and functional features in Hanwoo steers, highlighting the importance of microbial characteristics in nutrient utilization and production efficiency.

Ozone in the troposphere is a greenhouse gas and a pollutant; hence, additional understanding of the drivers of tropospheric ozone evolution is essential. The El Niño–Southern Oscillation (ENSO) is a main climate mode and may contribute to the variations of tropospheric ozone. Nevertheless, there is uncertainty regarding the causal influences of ENSO on tropospheric ozone under a warming environment. Here, we investigated the links between ENSO and tropospheric ozone using Coupled Modeling Intercomparison Project Phase 6 (CMIP6) data over the period 1850–2014. Our results show that ENSO impacts on tropospheric ozone are primarily found over oceans, while the signature of ENSO over continents is largely nonsignificant. Springtime surface ozone is more sensitive to ENSO compared to other seasons. The response of ozone to ENSO may vary depending on specific air pressure levels in the troposphere. These responses are weak in the middle troposphere and are stronger in the upper and lower troposphere. There is high consistency across CMIP6 models in simulating the signature of ENSO on ozone over the lower, middle, and upper troposphere. While the response of tropical tropospheric ozone to ENSO is in agreement with previous works, our results suggest that ENSO impacts on tropospheric ozone over the northern North Pacific, American continent, and the midlatitude regions of the southern Pacific, Atlantic, and Indian oceans might be more significant than previously understood.

Objective: In this study, we investigated the effects of heat stress (HS) on rumen fermentation, blood parameters, and ruminal microbial communities in mid-lactating Holstein dairy cows in Korea.Methods: Our study involved 12 mid-lactation Holstein dairy cows aged 55.54 months with 2.5±0.65 parities and 100 to 200 days in milking (DIM), fed a total mixed ratio diet. Samples were collected during HS (temperature-humidity index [THI] = 81.69) and recovery (RC) period (THI 69.84). The samples were analyzed for rumen fermentation, blood parameters, heat shock proteins, and microbial communities in dairy cows.Results: The milk yield, milk fat, milk protein, and milk urea nitrogen levels differed significantly between two-time points (p<0.05). Rumen pH and volatile fatty acid concentrations, the pH was not significantly different (p = 0.619) between HS and RC periods; however, the ammonia nitrogen (NH3-N) levels increased during HS period ), however, there was no significant difference (p>0.05). Blood total protein significantly increased during HS period compared with that during RC period (p<0.05), while no significant differences were observed in other parameters between the two periods. HSP27, HSP70, and HSP90 increased in dairy cows under HS conditions compared with those during the RC period. Taxonomic classification revealed that Firmicutes and Bacteroidetes dominated the bacterial community. PERMANOVA and PERMDISP showed significant differences in rumen bacterial diversity between HS and RC periods, based on Unifrac metrics (p = 0.044 and p = 0.015, respectively), indicating taxonomic variations. Microbial networks with correlations of >0.8 (p<0.05) showed a complex structure with equal positive and negative connections, indicating Anaerohabdus furcosa and Ruminiclostridium cellobioparum as key species during the HS and RC periods respectively.Conclusion: HS significantly impacts Holstein dairy cows' physiological and metabolic processes, altering rumen fermentation, blood biochemistry, and gut microbiota during mid-lactation.

Burundi is susceptible to future water-related disasters, but examining the influence of climate change on regional hydroclimatic features is challenging due to a lack of local data and adaptation planning. This study investigated the influence of climate change on hydroclimate-focused changes in the climatology of heavy precipitation (and streamflow) means and extremes based on the multi-model ensemble mean of earth system models in the sixth phase of the Coupled Model Intercomparison Project (CMIP). For runoff analysis, hydrologic responses to future climate conditions were simulated using the Soil and Water Assessment Tool (SWAT) model over the Ruvubu River basin, Burundi. Temperature increases by 5.6 °C, with strong robustness, under future climate conditions. The mean annual precipitation (and runoff) undergoes large seasonal variations, with weak robustness. Precipitation (and streamflow) changes between the wet and dry seasons differ in signal and magnitude. However, alterations in both the amount and frequency of precipitation reveal the intensification of the water cycle due to anthropogenic climate change. Thus, the highest variability in the maximum daily streamflow is shown in months of long wet seasons, especially in the far future (2085). Without considering the regional climate characteristics and shared socioeconomic pathway (SSP) scenarios, this behavior is expected to be enhanced in 2085 (compared with 2045) and increase the severity of extreme precipitation and flood risk. Climate change will cause alterations in the magnitude and seasonal distributions of extreme precipitation (and streamflow). These findings could be important for flood planning and mitigation measures to cope with climate change in Burundi.

Korean native goats (Capra hircus coreanae) (KNG) and Hanwoo (Bos taurus coreanae) are indigenous breeds inhabiting Korea. This study compared the in vitro rumen fermentation characteristics, dry matter (DM) degradation, and ruminal microbial communities of Korean native goats and Hanwoo steers consuming rice hay (RH) and cotton fiber (CF). The pH, ammonia-nitrogen (NH3-N), and total volatile fatty acids (VFAs) production significantly differ (p < 0.05) across species in all incubation times. After 24 h, the pH, NH3-N, and total VFAs production were higher in Korean native goats than in Hanwoo steers. Total gas, molar proportion of propionate, and total VFAs were higher (p < 0.05) in RH than in CF for both ruminant species. DM digestibility of both substrates were higher (p < 0.05) in Hanwoo steers than in KNG. Both treatments in KNG produced higher (p < 0.01) microbial DNA copies of general bacteria than those in Hanwoo steers. Butyrivibrio fibrisolvens and Fibrobacter succinogenes had significantly higher DNA copies under RH and CF in Hanwoo steers than in Korean native goats. B. fibrisolvens, Ruminococcus albus, and Ruminococcus flavifaciens after 24 h of incubation had a higher abundance (p < 0.05) in RH than in CF. Overall results suggested that rumen bacteria had host-specific and substrate-specific action for fiber digestion and contribute to improving ruminal functions of forage utilization between ruminant species.

This study proposes an approach for the uncertainty quantification at each stage of a single hydrological process of water level predictions based on different sources of mean areal precipitation (MAP) forecasts by using an adaptive Bayesian Markov chain Monte Carlo (MCMC) approach. The MAP forecasts are derived from the McGill Algorithm for Precipitation Nowcasting by Lagrangian Extrapolation (MAPLE) system and a long short-term memory (LSTM) network. The predicted water levels at two stations in the Gangnam catchment, Seoul, South Korea, are processed with a coupled 1D/2D urban hydrological model (1D/2D-UHM) forced by MAPLE MAP forecasts and LSTM-corrected MAP forecasts of five heavy rainfall events. The proposed Bayesian approach using the delayed rejection and adaptive Metropolis (DRAM) algorithm was compared with the Metropolis-Hastings (MH) algorithm in the uncertainty estimation of Weibull distribution parameters. The uncertainty contributions of the stages and sources in the related process were analyzed, including quantitative precipitation estimation (QPE) inputs, MAP inputs and 1D/2D-UHM. The results indicate that the uncertainty contribution of the MAPLE MAP forecasting is the highest in the 3-hour forecasting time. The uncertainty contribution of the QPE input for MAPLE MAP forecasting is the smallest and that of two sources, including the LSTM-corrected MAP source, and MAP and the coupled model is more significant than that of the QPE input. This research showed that the adaptive Bayesian MCMC method using the DRAM algorithm might be a robust option in quantitative uncertainty analyses of a single hydrological process, especially for urban flood management.

Background This study investigated the effects of inorganic and organic minerals on physiological responses, oxidative stress reduction, and rumen microbiota in Holstein bull calves (123.81 ± 9.76 kg; 5 months old) during short-term heat stress (HS) and recovery periods. Eight Holstein calves were randomly assigned to four treatment groups: no mineral supplementation (Con), inorganic minerals (IM), organic minerals (OM), and high-concentration organic minerals (HOM) and two thermal environments (HS and recovery) using 4 × 2 factorial arrangement in a crossover design of four periods of 35 d. Calves were maintained in a temperature-controlled barn. The experimental period consisted of 14 d of HS, 14 d of recovery condititon, and a 7-d washing period. Results Body temperature and respiration rate were higher in HS than in the recovery conditions ( P  < 0.05). Selenium concentration in serum was high in the HOM-supplemented calves in both HS (90.38 μg/dL) and recovery periods (102.00 μg/dL) ( P  < 0.05). During the HS period, the serum cortisol was 20.26 ng/mL in the HOM group, which was 5.60 ng/mL lower than in the control group ( P  < 0.05). The total antioxidant status was the highest in the OM group (2.71 mmol Trolox equivalent/L), followed by the HOM group during HS, whereas it was highest in the HOM group (2.58 mmol Trolox equivalent/L) during the recovery period ( P  < 0.05). Plasma malondialdehyde and HSP70 levels were decreased by HOM supplementation during the HS and recovery periods, whereas SOD and GPX levels were not significantly affected ( P  > 0.05). The principal coordinate analysis represented that the overall rumen microbiota was not influenced by mineral supplementation; however, temperature-induced microbial structure shifts were indicated (PERMANOVA: P  < 0.05). At the phylum level, Firmicutes and Actinobacteria decreased, whereas Fibrobacteres, Spirochaetes, and Tenericutes increased ( P  < 0.05), under HS conditions. The genus Treponema increased under HS conditions, while Christensenella was higher in recovery conditions ( P  < 0.05). Conclusion HOM supplementation during HS reduced cortisol concentrations and increased total antioxidant status in Holstein bull calves, suggesting that high organic mineral supplementation may alleviate the adverse effects of HS.