Biogeochemistry of a glaciated fjord ecosystem: Glacier Bay National Park, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2015The burning of fossil fuels, coupled with land use and deforestation practices, has resulted in CO₂ being emitted into the atmosphere. As much as one third of the anthropogenic, or man-made, CO₂ that ends up in the atmosphere is absorbed by the oceans and has led to increases in marine dissolved inorganic carbon (DIC) concentrations and a decrease in ocean pH, a process referred to as ocean acidification (OA). Increased concentrations of DIC can reduce saturation states (Ω) with respect to biologically important calcium carbonate minerals, such as aragonite. However, CO₂ may not be the only factor in seasonal changes to calcium carbonate saturation states. With this project I was interested in understanding how glacial runoff impacts the seasonal changes to the marine biogeochemistry in a glaciated fjord. In addition to CO₂, glacial meltwater is low in alkalinity (TA) and may impact the seasonal biogeochemistry of the marine system, as well as how it influences the duration, extent, and severity of OA events in an Alaskan glacial fjord, Glacier Bay National Park (GLBA). Through this study, I found that glacial runoff heavily impacts aragonite saturation states, with the main drivers of Ω (DIC and TA) varying seasonally. In GLBA low Ω values were well correlated with the timing of maximum glacial discharge events and most prominent within the two regions where glacial discharge was highest. The influence of glaciers is not limited to just TA as runoff is also low in macronutrients due to a lack of leaching from the soil and rocky streambeds. This has the potential to greatly impact the efficiency and structure of the marine food web within GLBA, the lowest level of which can be estimated using net community production (NCP). Changes within the lowest level of the food web, as a result of seasonal OA events, may lead to bottom-up effects throughout the food web, though this project focused only on production and respiration signals within the lowest level. We estimated regional NCP values for each sampling season and found the highest NCP rates (~54 to ~81 mmoles C m⁻² d⁻¹) between the summer and fall of 2011, with the most marine influenced lower part of the bay experiencing the greatest production. As the climate continues to warm, further glacial volume loss will likely lead to additional modifications in the carbon biogeochemistry of GLBA. Understanding the dynamics that drive seasonal changes in Ω, NCP, and the associated air-sea CO₂ fluxes within glacially influenced Alaskan fjords can provide insights into how deglaciation may affect carbon budgets and production in similar fjords worldwide.1. General introduction -- 2. The dynamic controls on carbonate mineral saturation states and ocean acidification in a glacially dominated estuary -- 3. Assessing net community production in a glaciated Alaskan fjord -- 4. General conclusions

TRADITIONAL VS. HOME-BASED PHASE II CARDIAC REHABILITATION IN A RURAL SETTING: A RETROSPECTIVE STUDY

This dissertation addresses the following questions: 1) the impact of three environmental conditions (altitude, heat, and woodsmoke exposure) on the blood oxidative stress response to exercise; 2) the effect of exercise-based cardiac rehabilitation programs (home-based, HBCR; traditional, TCR) on health outcomes in those who have experienced a cardiovascular event and/or severe diagnosis resulting in referral to cardiac rehabilitation. Study 1: Examine effects of lab-simulated hypobaric and hypoxic conditions on oxidative stress during a 4-hour recovery period after 1-hour of cycling (70% watts max). Exercise increased markers of antioxidant status (TEAC, FRAP) and lipid damage (8-ISO) (p\u3c0.05). No effects of hypobaria and hypoxia were observed. Study 2: Compare the blood oxidative stress response to an exercise tolerance trial (1-hour, 50% Wpeak) in hot (33ºC) and room temperature (20ºC) environments following acclimation training (15 sessions). Exercise increased markers of antioxidant status (TEAC, FRAP) and lipid damage (LOOH) (p\u3c0.001). No effect of environmental temperature was observed. Study 3: Investigate the effect of woodsmoke exposure (200 μg·m-3) on variables of cardiovascular function (heart rate variability, HRV; pulse wave velocity PWV) and oxidative stress with 45-min of moderate intensity exercise (70% VO2max). Woodsmoke exposure did not reduce HRV, increase PWV, or increase oxidative stress (p\u3e0.05). Study 4: The final study was conducted to compare the effectiveness of TCR and HBCR as determined by improvements in exercise capacity (peak metabolic equivalents, peak METs), resting heart rate (RHR), resting systolic (SBP) and diastolic (DBP) blood pressure, body mass index (BMI), and depression outcomes (PHQ-9). Peak METs and PHQ-9 scores improved in both TCR and HBCR (p\u3c0.001); however, greater improvements in peak METs occurred with TCR (p=0.034). No association between intervention type and program completion was observed (p=0.172). The results of these investigations indicate 1) lab-simulated hypobaric and/or hypoxic conditions do not impact the oxidative stress response to exercise; 2) 15 sessions of acclimation training in a hot environment do not alter the oxidative stress response to an exercise tolerance trial; 3) Woodsmoke exposure (200 μg·m-3) with moderate intensity exercise did not negatively impact HRV, PWV or blood oxidative stress; 4) HBCR and TCR improve peak METs and PHQ-9 outcomes

Four weeks of trauma-informed yoga intervention and autonomic tone in female veteran and non-veteran college students

Introduction: Female college students (veteran and non-veteran) are exposed to cumulative stressors and trauma that may lead to an imbalanced autonomic nervous system. Yoga has emerged as an efficacious intervention for psychological and physical trauma; however, the therapeutic dose of intervening yoga is unknown. Additionally, the frequency, duration, and type of yoga needed to achieve a therapeutic dose appear to be population specific when applied to trauma victims. The purpose of the study was to examine whether a short-term trauma-informed yoga intervention altered metrics of autonomic tone as assessed by heart rate variability (HRV) in female veteran and non-veteran college students. Methods: Nine female college students (age: 33 years ± 11, veteran, n = 4, non-veteran, n = 5) engaged in trauma-informed yoga once per week for one-hour over a four-week intervention. Repeated measures ANOVA were performed on the HRV variables lnRMSSD, lnHF, lnLF, and LF:HF. Results: Findings indicated no effect of the intervention on HRV as measured by lnRMSSD (p = .116), lnHF (p = .073), lnLF (p = .316), and LF:HF (p = .131). Further, no acute alterations in HRV were observed following a single session of trauma-informed yoga (p > .05). Conclusion: The findings of the study revealed no significant effect of trauma-informed yoga on HRV following a single session or after a four-week yoga intervention

Determinants of the Scope and Strength of State Environmental Policy

Using bivariate crosstabulation and multivariate regression analysis this study attempted to measure the effects of political factors on the scope and strength of state environmental policy. Political variables included state political culture, interest group strength, partisanship, gubernatorial strength, legislative professionalism, and state innovativeness. Scope and strength of state environmental policy was measured by four dependent variables. The dependent variables measured state initiated policy, federally intitiated policy, per capita spending, and toxic substance control efforts. The dependent variables measuring state initiated and federally initiated policies are new attempts in measuring state environmental policy. They are indices that combine measured characteristics of states' environmental policies in different areas of environmental concern. Overall, the four dependent variables represent a comprehensive attempt to measure environmental policy in the fifty states.Political Scienc

Perceptions of Advertisers Regarding Attributes and Customer Services of Trade Magazines Featuring Activities of Agricultural Youth

Agricultural Education, Communications, and 4-H Youth Developmen

Health and fitness benefits using a heart rate intensity-based group fitness exercise regimen

Inactivity leads to morbidity and mortality, while novel and engaging approaches to fitness improve health outcomes. The current study examined an 8-week commercial group exercise regimen for high intensity interval training (HIIT) in order to examine comprehensive metrics of health and fitness. Aerobic fitness, body composition, resting metabolic rate, blood cholesterol and glucose, in addition to resting blood pressure were quantified in a laboratory setting independent of the training facilities. Exercise training utilized multimodal HIIT-based exercises and work intensity was gauged by real-time heart rate feedback. All participants completed the required two sessions per week. Pre-Post analyses indicate aerobic fitness (Pre VO2max = 36.8 ml•kg-1•min-1; Post VO2max = 40.8 ml•kg-1•min-1), % fat (Pre = 28.1%; Post = 27.0%), resting metabolic rate (Pre = 1557 kcals; Post = 1664 kcals), resting blood pressure (Pre = 128.8/78.1 mmHg; Post = 116.7/75.4 mmHg), and circulating triacylglycerol (Pre = 100.0 mg/dl; Post = 78.7 mg/dl) were significantly altered. This study quantified improvements in aerobic fitness, body composition, resting metabolic rate, resting blood pressure, and triacylglycerol after an 8-week HIIT regimen. The implications of heart rate (HR) monitoring within franchised group exercise with wearable technology serves as an unexplored scientific approach to understand novel exercise prescriptions on health-fitness outcomes. Future research should investigate sociological aspects of program adherence, while biological applications should examine the adaptive stimuli of HIIT training on health and fitness improvements.This work was supported by the Ultimate Fitness Group, LLC dba Orange Theory Fitness

A Comparison of Anaerobic Power Tests using Cycle Ergometry and Non-motorized Treadmill Ergometry at Optimized Loads

International Journal of Exercise Science 16(4): 1293-1305, 2023. The purpose of this study was to compare performance markers derived from a 30-second maximal bout on a cycle ergometer (CE) and non-motorized treadmill (NMT) under optimized loads. Recreationally active participants (n = 40) volunteered for the study. Force-velocity tests on the CE and NMT were used to determine optimal resistance for peak power (PP) production. The remaining visits were randomized and counterbalanced, with a single 30-second maximal test on CE or NMT to assess PP, mean power (MP), fatigue index (FI), over the course of the 30-second test, and maximum heart rate (HRmax) and blood lactate (BLa-) taken 1-minute post. Results were that PP and MP were higher (P\u3c0.05) on CE compared to NMT for both sexes. FI did not differ among males (P=0.201) whereas females showed higher FI (P=0.002) on the CE. HRmax and BLa- were higher (P\u3c0.05) after NMT for both sexes. There was no difference for optimal braking force on NMT between males (16.65±4.49%BW) and females (14.30±3.10%BW) (P=0.061). CE optimal torque factor was higher for males (0.78±0.16 Nm/kg) compared to females (0.62±0.14 Nm/kg) (P=0.001). Overall, CE produced higher power output using optimized loads in recreationally active males and females, while NMT test resulted in a higher HRmax andBLa- concentration. These tests for anaerobic power, when performed with optimized loads, produced different results for several variables, therefore these modalities should not be considered interchangeable. Practitioners should consider which modality best mimics the activities of the person being tested when selecting a protocol

Carbohydrate Rinse Fails to Enhance Cycling Performance or Alter Metabolic and Autonomic Recovery in Recreational Cyclists

The purpose of the study was to examine the effects of carbohydrate (CHO) mouth rinsing on autonomic and metabolic recovery as well as cycling performance. Ten male recreational cyclists (age = 30 ± 6 years, VO2peak = 54.5 ± 8.1 mL·kg-1·min-1) completed a randomized, double-blind, placebo-controlled, crossover designed study. A CHO or a placebo (PLA) rinse was administered every 12.5% of a work to completion trial (75%Wmax). Heart rate variability (lnRMSSD), the respiratory exchange ratio, and plasma epinephrine, norepinephrine, insulin, glucose, free fatty acids (FFA), and lactate were measured pre- and post-exercise. The CHO rinse did not improve time to completion of the test trial (CHO: 4108 ± 307 s, PLA: 4176 ± 374 s, p = 0.545). Further, the CHO rinse did not impact autonomic recovery, as measured by lnRMSSD (p = 0.787) and epinephrine (p = 0.132). Metabolic biomarkers were also unaffected by the CHO rinse, with no differences observed in responses of FFA (p = 0.064), lactate (p = 0.302), glucose (p = 0.113) or insulin (p = 0.408). Therefore, the CHO mouth rinse does not reduce the acute sympathetic response following strenuous exercise and does not result in improvements in cycling time to completion

The Effect of Dietary Carbohydrate and Fat Manipulation on the Metabolome and Markers of Glucose and Insulin Metabolism: A Randomised Parallel Trial.

From Europe PMC via Jisc Publications RouterHistory: ppub 2022-09-01, epub 2022-09-07Publication status: PublishedHigh carbohydrate, lower fat (HCLF) diets are recommended to reduce cardiometabolic disease (CMD) but low carbohydrate high fat (LCHF) diets can be just as effective. The effect of LCHF on novel insulin resistance biomarkers and the metabolome has not been fully explored. The aim of this study was to investigate the impact of an ad libitum 8-week LCHF diet compared with a HCLF diet on CMD markers, the metabolome, and insulin resistance markers. n = 16 adults were randomly assigned to either LCHF (n = 8, <50 g CHO p/day) or HCLF diet (n = 8) for 8 weeks. At weeks 0, 4 and 8, participants provided fasted blood samples, measures of body composition, blood pressure and dietary intake. Samples were analysed for markers of cardiometabolic disease and underwent non-targeted metabolomic profiling. Both a LCHF and HCLF diet significantly (p < 0.01) improved fasting insulin, HOMA IR, rQUICKI and leptin/adiponectin ratio (p < 0.05) levels. Metabolomic profiling detected 3489 metabolites with 78 metabolites being differentially regulated, for example, an upregulation in lipid metabolites following the LCHF diet may indicate an increase in lipid transport and oxidation, improving insulin sensitivity. In conclusion, both diets may reduce type 2 diabetes risk albeit, a LCHF diet may enhance insulin sensitivity by increasing lipid oxidation

Sarcoendoplasmic Reticulum Ca2+ ATPase. A Critical Target in Chlorine Inhalation–Induced Cardiotoxicity

Autopsy specimens from human victims or experimental animals that die due to acute chlorine gas exposure present features of cardiovascular pathology. We demonstrate acute chlorine inhalation–induced reduction in heart rate and oxygen saturation in rats. Chlorine inhalation elevated chlorine reactants, such as chlorotyrosine and chloramine, in blood plasma. Using heart tissue and primary cardiomyocytes, we demonstrated that acute high-concentration chlorine exposure in vivo (500 ppm for 30 min) caused decreased total ATP content and loss of sarcoendoplasmic reticulum calcium ATPase (SERCA) activity. Loss of SERCA activity was attributed to chlorination of tyrosine residues and oxidation of an important cysteine residue, cysteine-674, in SERCA, as demonstrated by immunoblots and mass spectrometry. Using cardiomyocytes, we found that chlorine-induced cell death and damage to SERCA could be decreased by thiocyanate, an important biological antioxidant, and by genetic SERCA2 overexpression. We also investigated a U.S. Food and Drug Administration–approved drug, ranolazine, used in treatment of cardiac diseases, and previously shown to stabilize SERCA in animal models of ischemia–reperfusion. Pretreatment with ranolazine or istaroxime, another SERCA activator, prevented chlorine-induced cardiomyocyte death. Further investigation of responsible mechanisms showed that ranolazine- and istaroxime-treated cells preserved mitochondrial membrane potential and ATP after chlorine exposure. Thus, these studies demonstrate a novel critical target for chlorine in the heart and identify potentially useful therapies to mitigate toxicity of acute chlorine exposure.This work was supported by the CounterACT Program, National Institutes of Health, Office of the Director, and the National Institute of Environmental Health Sciences grant U54 ES015678 (C.W.W.), and by Children’s Hospital of Colorado/Colorado School of Mines Pilot Award G0100394 and a Children’s Hospital of Colorado Research Institute’s Pilot Award (S.A.)